WO2008060935A2

WO2008060935A2 - Liquid dispensing apparatus

Info

Publication number: WO2008060935A2
Application number: PCT/US2007/084042
Authority: WO
Inventors: Paul S. Frates
Original assignee: Nordson Corporation
Priority date: 2006-11-15
Filing date: 2007-11-08
Publication date: 2008-05-22
Also published as: WO2008060935A3

Abstract

An apparatus (10) for dispensing an adhesive generally comprises a dispensing module (16), a liquid supply component (12), an actuating assembiy (42), and an attachment member (20). The actuating assembly (42) includes a three-way solenoid valve (24) that controls a flow of pressurized air to a piston (44), which in turn actuates a pivot arm (120) coupled to a valve element (112) within the dispensing module (16). The dispensing module (16) is coupled to the liquid supply component (12) by a clamping force applied by the attachment member (20).

Description

LIQUID DISPENSING APPARATUS

Cross-Reference to Related Applications

[0001] This application claims the priority of U.S. Application Serial No.

11/935,770, filed November s, 2007 {pending), U.S. Application Serial No.

1 1 /928,650, filed October 30, 2007 (pending) and U.S. Provisional Patent

Application Serial No. 60/865,886, filed November 15, 2006 (pending), the disclosures of which are fully incorporated by reference.

Technical Field

[0002] The present invention relates generally to liquid dispensers, and more specifically to hot melt adhesive dispensers having a dispensing module attached to a liquid supply component.

Background

[0003] A typical apparatus for dispensing a heated liquid, such as hot melt adhesive, generally includes a dispensing module having a valve element that opens and closes a dispensing outlet. The valve element is positioned within a passage supplied with pressurized liquid and contacts a valve seat to prevent the adhesive from flowing to the outlet. To dispense the adhesive, an actuator, such as an electrically and/or pneumatically operated actuator, causes the valve element to move away from the valve seat and allows the adhesive to flow from the passage to the outlet. A biasing mechanism, such as a spring, or the same actuator may then cause the valve element to move back toward the valve seat to close the outlet. [0004] Various arrangements have been developed for heated liquid dispensers. For example, U.S. Application Serial Nos. 10/975,227 ("the '227 application") and 10/907,514 ("the '514 application"), the disclosures of which are fully incorporated herein by reference, relate to dispensers in which a pivot arm operatively connects the valve element in a dispensing module to a piston in an adjacent housing. The piston is maintained in a first position within the housing by a spring or air pressure so that the pivot arm forces the valve element against a valve seat. A liquid supply component, such as a manifold, is coupled to the dispensing module on an opposite side from the housing and supplies heated liquid to a fluid passage around the valve eiement. Thus, when the piston member moves down, the pivot arm causes the valve element to move away from the valve seat so that the liquid within the fluid passage flows to an outlet.

[0005] Various areas for improvement exist, such as reducing complexity and increasing reliability of the actuating portion of the dispensing apparatus and reducing the size of the apparatus.

Summary

[0006] An apparatus for dispensing a heated liquid, such as hot melt adhesive, is provided. The apparatus generally includes a pivot arm that serves as a pivot actuator and an actuating assembly having a three-way solenoid valve for controlling the operation of the pivot actuator. The apparatus also provides an attachment system for coupling a dispensing module to a liquid supply component. Both the actuating assembly and attachment system allow the apparatus to be designed with a relatively small width. [0007] To this end, one embodiment of an actuating assembly includes a housing having a piston chamber, a piston configured to reciprocate within the piston chamber along a piston axis, and an opening extending into the piston chamber. The opening is configured to receive a portion of a pivot arm so that the piston may be coupled to a first end of the pivot arm. This enables the piston to drive a valve element coupled to a second end of the pivot arm within a dispensing module. A three-way solenoid valve is operatively coupled to the housing and includes an inlet port for receiving pressurized air, a first outlet port communicating with the inlet port, a second outlet port selectively communicating with the inlet port, and an exhaust port selectively communicating with the second outlet port. The solenoid valve may be coupled to the housing along the piston axis.

[0008] The solenoid valve may further include a poppet movable between a first position and a second position, in one embodiment, pressurized air always passes from the inlet port to the first outlet port and selectively passes from the inlet port to the second outlet port. More specifically, when the poppet is in the first position, the first outlet port communicates with the inlet port and the second outlet port communicates with the exhaust port. When the poppet is in the second position, both the first and second outlet ports communicate with the inlet port. The piston further includes a piston head sealingly engaging the piston chamber, and the first and second outlet ports of the solenoid valve direct pressurized air at respective top and bottom surfaces of the piston head to operate the piston. [0009] The actuating assembly may also include a thermal isolator positioned between the solenoid valve and housing. In such an embodiment, the thermal isolator includes a first passage extending from the first outlet port to a portion of the piston chamber communicating with the bottom surface of the piston head, a second passage extending from the second outlet port to a portion of the piston chamber communicating with the top surface of the piston head, and a third passage configured to direct pressurized air from the exhaust port to outside the thermal isolator. The thermal isolator may be formed from a thermaily insulating material to reduce heat transfer from the housing to the solenoid valve.

[0010] The actuating assembly may be incorporated into a wide variety of liquid dispensing apparatuses. In one illustrative embodiment, an adhesive dispensing apparatus includes a dispensing module and the actuating assembly, with the housing of the actuating assembly being positioned proximate the dispensing moduie. The dispensing module includes a liquid inlet, a liquid passage in communication with the liquid inlet, an outlet in communication with the liquid passage, and a valve element movable within the liquid passage to selectively allow and prevent flow of the adhesive through the outlet. A pivot arm extending into the dispensing module operatively couples the piston of the actuating assembly to the valve element within the dispensing module.

[0011] In a further embodiment, the apparatus also includes a liquid supply component, such as a manifold or service block, coupled to the dispensing module and having a supply passage for directing adhesive to the liquid inlet. The housing of the actuating assembly may be at least partially received in the liquid supply component and may include a reduced diameter section defining a portion of the supply passage. To this end, adhesive may flow around the housing between the reduced diameter section and the liquid supply component. [0012] In another illustrative embodiment, an adhesive dispensing apparatus includes a plurality of the dispensing modules coupled to a liquid supply component. A plurality of pivot arms each extend into a corresponding one of the dispensing modules and are each coupled to a valve element within the corresponding dispensing module. The apparatus aiso includes a plurality of actuating assemblies corresponding to the plurality of dispensing modules. To this end, each actuating assembly includes a housing at ieast partially received in the liquid supply component and a piston configured to reciprocate within a piston chamber of the housing, with the piston being operatively coupled to a corresponding one of the valve elements by one of the pivot arms. The actuating assemblies also include a three-way solenoid valve for operating the piston in the manner briefly discussed above and explained in further detail below.

[0013] Each dispensing module may be coupled to the liquid supply component using one of the attachment systems such that conventional fasteners do not need to be inserted through each dispensing module. If desired, however, the attachment systems may be combined with conventional fastening techniques to couple the dispensing modules to the liquid supply component.

[0014] To this end, one embodiment of such an attachment system generally comprises a stationary component and an attachment member. The attachment member includes a first portion configured to be pivotaliy coupled to the stationary component and a second portion configured to apply a clamping force to a dispensing module to couple the dispensing module to the stationary component. The stationary component may be, for example, a portion of the liquid supply component or a separate component secured to the liquid supply component.

[0015] In an adhesive dispensing apparatus including a dispensing module and the attachment system, the dispensing module may include, for example: a liquid inlet, an internal passage communicating with the liquid inlet, an outlet communicating with the internal passage, and a valve element movable within the internal passage to selectively allow and prevent flow of adhesive through the outlet. Additionally, the attachment member in the attachment system may include an opening extending through the first portion and may be movable between a first position in which it applies the damping force and a second position in which it allows the dispensing module to be moved away from the stationary component. The stationary component may include a hole configured to engage a fastener after the fastener is inserted through the opening in the attachment member when the attachment member is in the first position.

[0016] In another embodiment, the adhesive dispensing apparatus further includes a liquid supply component, such as a manifold or service block. Again, the stationary component in the attachment system may be an integral part of the liquid supply component or may be a separate component secured to the liquid supply component to form an assembly.

[0017] The attachment system may be incorporated into a wide variety of liquid dispensing apparatuses having one or more dispensing modules and one or more liquid supply components. In one illustrative embodiment, an adhesive dispensing apparatus includes a plurality of dispensing modules and a plurality of attachment systems, which may correspond to the plurality of dispensing modules. The attachment member in each attachment system includes a first portion pivotally coupied to a respective stationary component or a common stationary component, such as a liquid supply component that supplies the adhesive to the plurality of dispensing modules. Aiso, the attachment members may each include a second portion configured to apply a clamping force to a corresponding one of the pluraiity of dispensing modules or to several of the dispensing modules.

[0018] In another embodiment, a dispensing module comprises a body having a top surface, a front surface, an iniet surface opposite the front surface, a liquid inlet on the inlet surface, an internal passage communicating with the liquid inlet, an outlet communicating with the internal passage, and a valve element movable within the internal passage to selectively allow and prevent flow of the adhesive through the outlet. A recess defined in the front surface of the body includes a first section extending downwardly from the top surface, the first section being shaped to accommodate an elongate section of an attachment member, and a second section shaped to accommodate a head section of the attachment member. Additionally, at least a portion of the first section may have a first depth relative to the front surface and at least a portion of the second section may have a second depth greater than the first depth so as to define an overhang in the recess.

[0019] When a liquid dispensing apparatus incorporates an attachment member according to one embodiment of the invention, the dispensing module may be easily coupled to the liquid supply component. For example, one method of releasably attaching a dispensing module to a liquid supply component comprises moving the attachment member from a first position to a second position, the attachment member being pivotally coupled to the liquid supply component. The dispensing module is then positioned in a desired position relative to the liquid supply component. Once the dispensing module is positioned, the attachment member is moved from the second position to the first position to retain the dispensing moduie in the desired position. [0020] Another method of releasabiy attaching a dispensing module to a liquid supply component comprises positioning the dispensing module in a desired position relative the liquid supply component and positioning an attachment member relative to the dispensing moduie and the liquid supply component. The attachment member includes a first portion configured to confront the liquid supply component, an opening extending through the first portion, and a second portion configured to confront the dispensing module. A fastener is inserted through the opening in the attachment member and into a hole provided in the liquid supply component. The fastener is then rotated in a first direction to engage internal threads in the hole of the liquid supply component. Because the fastener includes a head retained against the attachment member, the second portion of the attachment member applies a clamping force to the dispensing module when the fastener is sufficiently rotated .

[0021] In a further aspect or embodiment of this illustrative method, the first portion of the attachment member is pivotaily coupled to the liquid supply component and the attachment member is movable from a first position to a second position. To position the attachment member relative to the dispensing module and the liquid supply component, the attachment member is rotated from the second position to the first position. The attachment member may initially retain the dispensing moduie in the desired position when rotated into the first position so that the steps involving the fastener may then be performed without having to stabilize or hold the dispensing module with one or more hands. However, the dispensing module may still be stabilized or held if desired.

Brief Description of the Drawings

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention.

[0023] Fig. 1 is a perspective view of an apparatus for dispensing heated liquid, such as hot melt adhesive, according to one illustrative embodiment.

[0024] Fig. 2 is a side elevationa! view of the apparatus of Fig. 1.

[0025] Fig. 3 is a perspective view of an actuating assembly incorporated into the apparatus of Fig. 1.

[0026] Fig. 4 is a front elevationa! view of the actuating assembly shown in Fig. 3.

[0027] Fig. 5 is a side elevational view of the actuating assembly shown in Fig. 3.

[0028] Fig. 5A is a side elevational view of an actuating assembly according to an alternative embodiment.

[0029] Fig. 6 is a cross-sectional side view of the actuating assembly shown Fig. 3.

[0030] Fig. 7 is a cross-sectional side view of the apparatus of Fig. 1 .

[0031] Fig. 8 is a perspective view of an apparatus for dispensing heated liquid according to another illustrative embodiment.

[0032] Fig. 9 is a perspective view of an apparatus for dispensing heated liquid according to yet another illustrative embodiment. [0033] Fig. 10 is a perspective view of the apparatus of Fig. 9, showing a dispensing module disassembled from a liquid supply component.

[0034] Fig. 1 1 is a perspective view of the dispensing module of Fig. 10.

[0035] Fig. 12 is a partial cross-sectional view of the apparatus of Fig. 9, showing an attachment member in a position operative to allow the dispensing module to be moved away from the liquid supply component.

[0036] Fig. 13 is a partial cross-sectional view similar to Fig. 12, showing an attachment member in a position operative to securely retain the dispensing module relative to the liquid supply component.

[0037] Fig. 14 is a schematic cross-sectional view of the apparatus of

Rg. 9.

[0038] Fig. 15 is a perspective view of an apparatus for dispensing heated liquid according to another illustrative embodiment.

[0039] Figs. 16A and 16B are perspective views of a portion of an attachment member according to one iliustrative embodiment being used with a conventional dispensing module.

[0040] Fig. 17 is a perspective view of an attachment member according to another iliustrative embodiment being used with two dispensing modules.

Detailed Description of the Drawings

[0041] Figs. 1 and 2 show one illustrative embodiment of an apparatus

10 for dispensing a liquid, such as an adhesive. Furthermore, the liquid may be a heated liquid, such as hot melt adhesive. The apparatus 10 generally includes a liquid supply component 12 (sometimes referred to as a manifold or service block) adapted to receive adhesive from a hose 14 and a dispensing module 16 in fluid communication with the liquid supply component 12. The dispensing module 16 is adapted to dispense the liquid through a nozzle 18 and may be coupled to the liquid supply component 12 by an attachment member 20, as will be described in greater detail below. [0042] In one embodiment, the apparatus 10 further includes a housing

22 proximate the dispensing module 16 and a solenoid valve 24 operatively coupled to the housing 22. The solenoid valve 24 and housing 22 may be secured together as a part of an actuating assembly 42 (Fig. 3) and positioned within a portion of the liquid supply component 12 as shown. Although the solenoid valve 24 and housing 22 are shown as being arranged in a generally linear and/or vertical manner substantially along a piston axis 66 (Fig. 6), other configurations are possible. For example, the housing 22 may alternatively be positioned on an opposite side of the dispensing module 16 than the liquid supply component 12 and the solenoid valve 24 may be operativeiy coupled to the housing 22 in a side-by-side arrangement.

[0043] With reference to Figs. 3-6, the actuating assembly 42 is shown in further detail. The solenoid valve 24 may be a three-way, poppet-type valve having an inlet port 26, a first outlet port 28, a second outlet port 30, and an exhaust port 32. For example, the solenoid valve 24 may be a modified Series 33A valve distributed by Mac Valves, Inc., located in Wixam, Michigan. The modifications may include a larger outer body 34 having fins 36 to help dissipate heat, a jacketed or reinforced cable 38 protecting electrical wires (not shown) that supply electrical current to the solenoid valve 24, and arranging the ports 26, 28, 30, 32 in the manner shown in Fig. 6. Because the internal components of the solenoid valve 24 operate in substantially the same manner as the Series 33A valves commercially available from Mac Valves, only a general overview of their operation is described below. [0044] A constant source of pressurized fluid or gas, such as air, is supplied to the inlet port 26 and directed to the first outlet port 28. In one embodiment, the first outlet port 28 communicates with the inlet port 26 at ail times. In this initial position, a poppet (not shown) within the body 34 allows the second outlet port 30 to communicate with the exhaust port 32. When the solenoid valve 24 receives electrical current from the wires within the cable 38, an electrical field is created that moves an armature {not shown) within the body 34 from a first position to a second position. The poppet is coupled to the armature by a push pin 40 and moves with the armature along an axis 41 , which may be generally transverse to the piston axis 66. In the second position, the poppet allows communication between the inlet port 26 and the second outlet port 30. As a result, the inlet port 26 simultaneously directs pressurized air to both the first and second outlet ports 28, 30. The solenoid valve 24 is then de-energized and a spring (not shown) within the body 34 returns the armature and poppet to their initial positions. Pressurized air that was supplied to the second outlet port 30 may be released through the exhaust port 32 when the poppet returns to its initial position. [0045] The housing 22 includes a piston chamber 46 and a piston 44 mounted for reciprocation within the piston chamber 46 along piston axis 66. More specifically, the housing 22 includes a piston 44 having a piston head 48, an intermediate portion 50, and a piston shaft 52. At least one O-ring or other seal 54 is provided around the piston head 48 to seal off a first portion 56 of piston chamber 46 communicating with a top surface 58 of piston head 48 from a second portion 60 of piston chamber 46 communicating with a bottom surface 62 of piston head 48. The intermediate portion 50 includes at least one O-ring or seal 64 as well so that the second portion 60 is sealed off from a remainder of the piston chamber 46, The seals 54, 64 may be hat seais that engage corresponding seal surfaces 55, 65 (Fig. 6) within the piston chamber 46. Providing this type of seal may help minimize seal friction that resists movement of the piston 44 within the piston chamber 46. As a result, less air pressure may be required to move the piston 44. Additionally, hat seals typically operate well at high temperatures and reduce wear so as to enable longer seal life.

[0046] The design of the piston chamber 46 may also contribute to ionger seal life. In particular, the piston chamber 46 may further include a bearing surface 68 (Fig, 6) designed to guide the piston shaft 52 during its movement relative to the piston chamber 46. The bearing surface 68 may define a continuous through-bore through a portion of the housing 22. Additionally, the bearing surface 68 and first and second seal surfaces 55, 65 may be aϋgned along the piston axis 66. Such an arrangement helps reduce side loads on the seals 54, 64 and the piston head 48, which leads to a reduction in overall wear and increases the life of the components. [0047] Although the housing 20 is shown as a single component, it will be appreciated that the actuating assembly 42 may alternatively include a housing constructed from two or more components. For example, Fig. 5A shows a two-piece housing 22' defined by a first housing component 67 and a second housing component 69. The first and second housing components 67, 69 may be received in the liquid supply component 12 (Fig. 1 ) so that a space or gap 70 is maintained therebetween.

[0048] Still referring to Figs. 3-6, a thermal isolator 72 may be positioned between the solenoid valve 24 and housing 22. The thermal isolator 72 is formed from a thermally insulating material to reduce heat transfer from the housing 22 to the soienoid valve 24. In addition to this function, the thermal isolator 72 includes various passages for directing pressurized air from the ports of the solenoid valve 24 to the housing 22. Specificalϊy, a first passage 74 is configured to extend from the first outlet port 28 of solenoid valve 24 to an inlet passage 76 of housing 22, which in turn communicates with the second portion 60 of piston chamber 46. The first passage 74 therefore allows pressurized air to be directed from the first outlet port 28 to the bottom surface 62 of piston head 48. An O-ring or other seal 78 may be provided around the first passage 74 at the interface between the thermal isolator 72 and housing 22 to prevent leakage.

[0049] A second passage 80 within the thermal isolator 72 is similarly configured to extend from the second outlet port 30 to the first portion 56 of piston chamber 46. An O-ring or other seal 82 may be provided between the piston chamber 46 and a lower portion 84 of thermal isolator 72 extending into the piston chamber 46 to seal off the first portion 56 of piston chamber 46. Thus, the second passage 80 is configured to direct pressurized air to the first portion 56 and at the top surface 58 of piston head 48. A third passage 86 in the thermal isolator 72 is configured to direct air from the exhaust port 32 of solenoid valve 24 to an area outside the thermal isolator 72. [0050] The components of the actuating assembly 42 may be secured together using conventional fastening techniques. For example, bolts 88 may be used to secure the thermal isolator 72 to the housing 22. By arranging the components along the piston axis 66, the actuating assembly 42 may be designed to have a very small width. In one embodiment, the actuating assembly 42 is approximately 16 mm wide. Such a configuration reduces the amount of space occupied by the apparatus 10, which may be helpful when designing a larger system to include the apparatus 10. [0051] Fig. 7 shows the actuating assembly 42 incorporated into the apparatus 10. The housing 22 may be positioned within a corresponding slot, bore, or other recess 90 in the liquid supply component 12 between the dispensing module 16 and hose 14. To supply adhesive to the dispensing module 16, a supply passage 92 extends from the hose 14, around the housing 22, and to a liquid inlet 94 in the dispensing module 16. Thus, an outer surface 96 {Figs. 3-6) of housing 22 and the recess 90 cooperate to define a portion 98 of supply passage 92. In one embodiment, the outer surface 96 includes a reduced diameter section 100 between two seals 102, 104 (e.g., O-rings) to help define the portion 98. Such an arrangement increases the size of the portion 98 and allows a greater amount of adhesive to flow around the housing 22 (increased flow capability).

[0052] The dispensing module 16 may be coupled to the liquid supply component 12 by the attachment member 20 (discussed in further detail below) or by conventional fasteners (not shown) extending through the dispensing module 16. In addition to the liquid inlet 94, the dispensing module 16 further includes a liquid passage 108 communicating with the liquid inlet 94 and an outlet 110 communicating with the liquid passage 108. A valve element 112 situated within the dispensing module 16 is adapted to move (e.g., reciprocate) within the liquid passage 108 to selectively prevent and allow the flow of adhesive through the outlet 110. More specifically, the valve element 1 12 includes a valve tip 1 14 configured to selectively engage a valve seat 116 within the dispensing module 16. The engagement between the valve tip 1 14 and the valve seat 116 cuts off fluid communication between the liquid passage 108 and outlet 1 10, thus preventing the adhesive from flowing out of the dispensing module 16. When the valve tip 1 14 is moved away from the valve seat 116, adhesive within the liquid passage 108 flows to the outlet 1 10 and exits the dispensing module 16. As described in greater detail below, pressurized air within the second portion 60 of piston chamber 46 and, if necessary, a spring or other biasing element 1 18 return the vaive element 112 to its initial position against the valve seat 1 16 to once again cut off fluid communication between the liquid passage 108 and outlet 1 10. [0053] The vaive element 1 12 is operatively coupled to the piston 44 by a pivot arm 120. The pivot arm 120 includes a first end 122 that couples to the piston shaft 52. For example, in the embodiment shown in Fig. 7, the first end 122 is a ball that is configured to be received within a bore 124 machined or otherwise formed in the piston shaft 52. The bore 124 may have an elongate, oval-iike cross-section so that it can receive the first end 122 even if there is some misalignment between the parts. A second end 126 of pivot arm 120 couples to the valve element 1 12 in a similar manner. Thus, the pivot arm 120 extends through both an opening 128 in housing 22 and a flexible seal 130 in dispensing module 16 so that the second end 126 is received in a through-bore 132 machined in the valve element 112. The pivot arm 120 pivots about a pin 134 coupled to the dispensing module 16 so that, as viewed in Fig. 7, downward motion of the piston 44 results in upward motion of the valve element 1 12. Conversely, upward motion of the piston 44 results in downward motion of the valve element 112. The flexible seal 130 prevents pressurized adhesive within the liquid passage 108 from leaking out of the dispensing module 16 at ail times (i.e., when the pivot arm 120 is stationary and when the pivot arm 120 pivots about the pin 134). [0054] In use, heated liquid, such as hot meit adhesive, is supplied to the liquid supply component 12 under controlled pressure by the hose 14. The adhesive is directed through a filter 136 (Fig. 7) and into the supply passage 92, where it flows around the housing 22 (via the portion 98 of supply passage 92) and to the liquid inlet 94 of dispensing module 16. The adhesive then travels into the liquid passage 108 to occupy the space around the vaive element 1 12 and valve seat 116.

[0055] Additionally, air is supplied to the inlet port 26 of solenoid vaive 24 under controlled pressure. In one embodiment, the pressurized air is always directed to the first outlet port 28, through the first passage 74 in thermal isolator 72, and into the second portion 60 of piston chamber 46 via the inlet passage 76. Thus, pressurized air occupies the second portion 60 and exerts pressure against the bottom surface 62 of piston head 48. This pressure maintains the piston 44 in an upward position so that the pivot arm 120 pushes downwardly on the valve element 112. The vaive tip 114 engages the valve seat 1 16 in this initial position so that the adhesive within the liquid passage 108 is prevented from flowing to the outlet 1 10.

[0056] To dispense the adhesive, electric current supplied through the cable 38 energizes the solenoid valve 24. The current creates an electrical field that causes the poppet within the solenoid valve 24 to shift from a first position to a second position in which the second outlet port 30 is placed in communication with the inlet port 26. As a result, the iniet port 26 now directs pressurized air to both the first and second outlet ports 28, 30. The pressure of the air within the first passage 74 of the thermal isolator 72 and the second portion 60 of piston chamber 46 is maintained in these areas. [0057] Meanwhile, as pressurized air supplied to the second outlet port

30 flows through the second passage 80 in thermal isolator 72 and into the first portion 56 of piston chamber 46, it exerts pressure against the top surface 58 of piston head 48. Although the pressure of the air in the first portion 56 is the same as the pressure of the air in the second portion 60, the top surface 58 has a greater amount of area exposed to the air than the bottom surface 62. Thus, a greater total force is applied to the piston head 48 by the pressurized air in the first portion 56 than by the pressurized air in the second portion 60. The result is a net downward force sufficient to overcome any seal friction and resistance to movement created by the spring 1 18 via the valve element 112 and pivot arm 120. This force drives the piston 44 downwardly in the piston chamber 46, causing the pivot arm 120 to pivot about the pin 134 so that the second end 126 moves the valve element 112 upward within the liquid passage 108 and away from the valve seat 116. The adhesive then flows from the liquid passage 108 to the outlet 1 10, where it is dispensed from the apparatus 10. [0058] When current is no longer supplied to the solenoid valve 24, the poppet returns to its initial position so that the second outlet port 30 does not communicate with the inlet port 26 and instead communicates with the exhaust port 32. Pressurized air is still supplied to the second portion 60 of piston chamber 46 via the first outlet port 28 such that an upward force is maintained against the bottom surface 62 of the piston head 48. As a result, the piston 44 moves upwardly within the piston chamber 46 and the pressurized air previously supplied to the first portion 56 is exhausted through the exhaust port 32 and out of the third passage 86. The upward movement of the piston 44 causes the pivot arm 120 to drive the valve element 112 downward until the valve tip 114 engages the valve seat 116. The spring 118 also exerts forces against the vaive element 112 to facilitate this movement. Advantageously, the spring 118 may serve as a back up to the pressurized air in the piston chamber 46. in other words, the spring 1 18 may help ensure that the valve element 1 12 returns to its initial position against the valve seat 1 16 in case pressurized air is not maintained in the second portion 60 or is not consistently supplied to the first outlet port 28. When the piston 44 returns to its upward, initial position, the valve element 112 once again prevents the adhesive from being dispensed from the outlet 110.

[0059] At this point current may be supplied to the solenoid valve 24 to begin a second dispensing cycle. The apparatus 10 may be operated at very rapid speeds because of its efficient design. For example, the apparatus 10 may dispense adhesive at speeds of approximates 10,000 cycles per minute. The apparatus 10 may dispense the adhesive as beads or in a stitched pattern. [0060] Additionally, the use of a three-way solenoid valve to operate the apparatus 10 has many advantages. In particular, three-way solenoid valves are typically more forgiving of contaminants and cheaper in cost than four-way solenoids and other types of valves. The reliability of three-way solenoid valves helps ensure that the apparatus 10 is able to operate for many dispensing cycles without failure. For example, the solenoid valve 24 in the apparatus 10 may be capable of operating for 100 million total cycles under normal operating conditions.

[0061] Three-way solenoid valves also have relatively simple designs and can be designed to fit in small spaces. As noted above, the actuating assembly 42 incorporating the solenoid valve 24 may be approximately 16 mm wide. Because solenoid valves of this magnitude (small in size) typically have limited flow capacities, the volume of air moved through the valves must typically be kept to a minimum. Additionally, relatively smali pistons, such as piston 44, can require relatively high pressures to operate (typically 70 psig). The mechanical advantage provided by the pivot arm ratio (the distance from the pin 134 to the first end 122 of pivot arm 120 divided by the distance from the pin 134 to the second end 126 of pivot arm 120) helps ensure that this pressure is sufficient to operate the valve element 1 12 within the dispensing module 16. Greater ratios require less air pressure to move the valve element 1 12 away from the valve seat 116.

[0062] Increasing the pivot arm ratio increases the distance the piston 44 must travel to move the valve element 1 12 a particular distance. As a result, the first and second portions 56, 60 of the piston chamber 46 become larger such that a greater volume of air is required to operate the piston 44. In one embodiment, the pivot arm ratio and the ratio between the exposed areas of the top and bottom surfaces 58, 62 of piston head 48 are optimized so that when operated by air supplied at 70 psig or iess, the dispensing time of the apparatus 10 (i.e., the time that the valve element 1 12 is retracted from the valve seat 116 so liquid adhesive flows through the outlet 1 10) is approximately 2.5 milliseconds or less and the time between cycles (i.e., the time that the valve element 1 12 is in contact with the valve seat 116) is approximately 6 milliseconds or less. In such an embodiment the pivot arm ratio may be approximately 1 .42— with the distance from the pin 134 to the first end 122 being approximately 0.475" and the distance from the pin 134 to the second end 126 being approximately 0.335" — and the ratio between exposed areas of the top and bottom surfaces 58, 62 may be approximately 2.54 — with the diameter of the piston head 48 being approximately 0.56" and the diameter of the intermediate portion 50 being approximately 0.436". in another embodiment, the ratio between exposed areas of the top and bottom surfaces 58, 62 is approximately 2.28, with the diameter of the piston head 48 being approximately 0.5" and the diameter of the intermediate portion 50 being approximately 0.375".

[0063] Fig. 8 illustrates an adhesive dispensing apparatus 210 according to another embodiment, with like reference numbers being used to refer to like structure from the embodiment shown in Figs. 1-7. The apparatus 210 includes a liquid supply component 212, such as a manifold or service block, that supplies hot melt adhesive to a plurality of the dispensing modules 16. To this end, the apparatus 210 also includes a plurality of actuating assemblies 42 each at ieast partially received in the liquid supply component 212. Each actuating assembly 42 may be received, for example, in a corresponding slot, bore, or other recess 90 (Fig. 7) provided in the liquid supply component 212. The piston in each actuating assembly 42 is operatively coupled to a valve element in a corresponding one of the dispensing modules 16 by a corresponding pivot arm (not shown). Because each actuating assembly 42 may be designed with a relatively small width, the liquid supply component 212 may receive a relatively large number of actuating assemblies 42 across its length. And because the number of dispensing modules 16 may correspond to the number of actuating assemblies 42, the dispensing modules 16 are designed with a relatively small width as well. The attachment members 20 allow for such a design.

[0064] In particular, the attachment members 20 are each configured to apply a clamping force to a corresponding one of the dispensing modules 16. Because the clamping forces secure the dispensing modules 16 relative to the liquid supply component 212, the dispensing modules 16 need not include holes for receiving fasteners (not shown), which would otherwise be required to couple the dispensing modules 16 to the liquid supply component 212. Thus, the space concerns typically created by the need to accommodate such fasteners (without interfering with the internal passages and structures shown in Fig. 7 within each dispensing module 16) may be reduced or eliminated by the attachment members 20.

[0065] The structure and operation of the attachment members 20 will be described with reference to Figs. 9-15, which illustrate an apparatus 310 for dispensing heated liquid according to an alternative embodiment. Like reference numbers are used in Figs. 9-15 to refer to like structure from the embodiments shown Figs. 1 -8. The apparatus 310 therefore includes one of the dispensing modules 16 and an attachment member 20, along with a liquid supply component 312 similar to the liquid supply component 12 (Fig. 1 ). Only a brief description of the liquid supply component 312 will be provided below because the attachment member 20 operates upon the same principles in both embodiments. Indeed, those skilled in the art will appreciate that the attachment member 20 may be incorporated into many different types of liquid dispensing apparatuses, such as electric guns and other dispensing apparatuses that do not include the actuating assembly 42 (Fig. 3). [0066] In one embodiment, the apparatus 310 is a gun and the liquid supply component 312 is a manifold that supplies adhesive to the dispensing module 16. For example, Figs. 1 1 and 14 show the dispensing module 16 including a dispensing module body 316 having an inlet surface 318 provided with the liquid inlet 94 for receiving the adhesive. The liquid inlet 94 communicates with the liquid passage 108 within the dispensing module body 316, which in turn communicates with the outlet. A hole or opening 320 may also be provided on the inlet surface 318 to accommodate the pivot arm 120 and flexible seal 130. As discussed above, the pivot arm 120 actuates the valve element 112 within the liquid passage 108.

[0067] Now referring to Figs, 10 and 1 1 , the liquid supply component 312 includes a main body portion 324 having a front surface 326 and a front body portion 328 extending from the main body portion 324 above the front surface 326. The front body portion 328 defines a channel 330 and includes opposed pin holes 332a, 332b for accommodating a pivot pin 334 that extends through the channel 330. Because adhesive is transferred between the liquid supply component 312 and the dispensing moduie 16, the liquid supply component 312 may further include a number of additional features on the front surface 326 to accurately interface with the dispensing module 16 and to prevent leakage. For example, when the liquid supply component 312 and the dispensing moduie 16 are assembled, the pivot arm 120 may enter an opening 336 provided in the front surface 326. Additionally, a flow dam 340 extending from the front surface 326 may register with a similarly-shaped channel 342 formed in the dispensing module 16, so that together the flow dam 340 and channel 342 can divert any leaking adhesive away from the pivot arm 120. Although the flow dam 340 and channel 342 are shown as having an arcuate configuration, these components may alternatively have a circular configuration. Alignment may be aided by dowel pins 346, a dowel hole 348, and a dowel slot 350, although a variety of other alignment devices may be used to accurately align the dispensing module 16 and liquid supply component 312. The number of alignment devices may also vary (e.g., only one dowel pin may be used in some embodiments). [0068] The attachment member 20 is movable from a first position in which it couples the dispensing module 16 to the liquid supply component 312 and a second position in which it allows the dispensing module 16 to be moved away from the liquid supply component 312, as will be described below. Those skilled in the art will appreciate that the attachment member 20 may be any type of lever, latch, handle, or other structure configured to be coupled to the liquid supply component 312 and configured to apply a clamping force to the dispensing module 16 to secure the dispensing module 16 relative to the liquid supply component 312.

[0069] For example, with reference to Figs. 10 and 14, the attachment member 20 may include a first portion 352 pivotally coupled to the front body portion 328 of liquid supply component 312 and a second portion 354 extending from the first portion 352. More specifically, the first portion 352 is received in the channel 330 and may include a pivot hole 356 for receiving the pivot pin 334 so as to be rotatably supported thereby. The second portion 354 may include an elongate section 358 and a head section 360, with the head section 360 having a bottom surface 362 configured to confront (i.e., face) the dispensing module 16. A projection 364 extends outwardly from the bottom surface 362 and terminates in a clamping surface 366. [0070] The attachment member 20 may further include an opening, such as a fastener hole 368, through which a fastener 370 passes. In the illustrative embodiment shown in Figs. 10 and 14, the fastener hole 368 is located in the first portion 352 between the between pivot hole 356 and the second portion 354. The first portion 352 has a greater thickness than the second portion 354 to strengthen the attachment member 20 in the area surrounding the fastener hole 368 so that greater forces may be exerted by a head 372 of the fastener 370, as will be described in greater detail below. Because of the different thicknesses in the attachment member 20, the elongate section 358 may decrease in thickness as it extends from the first portion 352 to the head section 360. The thicknesses, shapes, and spatial relationships between the first portion 352, second portion 354, pivot hole 356, and fastener hole 368 are not meant to be limiting, as other combinations of these features, if properiy arranged, wiil also work.

[0071] The second portion 354 of attachment member 20 is configured to be received into a recess 374 defined in a front surface 376 of the dispensing module body 316. The recess 374 may include: 1 ) a first section 378 extending downwardly from a top surface 380 of the dispensing module body 316 and shaped to accommodate the elongate section 358, and 2) a second section 382 shaped to accommodate the head section 360. To this end, the first section 378 may be tapered so as to decrease in depth (relative to the front surface 376) as the first section 378 extends downwardly from the top surface 380, much like the elongate section 358 of the attachment member 20. [0072] In one embodiment, at least a portion of the first section 378 has a first depth and at least a portion of the second section 382 has a second depth greater than the first depth so as to define an overhang in the recess 374. For example, the second section 382 may include a socket 384 defined by a substantially cylindrical surface 386 extending from a bottom surface 388 to a contact surface 390 located at the second depth. The head section 360 of the attachment member 20 may have a shape substantially corresponding to that of the socket 384, with the clamping surface 366 configured to contact the contact surface 390. Additionally, the socket 384 may be substantially aligned along a common axis 392 with the opening 320 on the inlet surface 318 so that clamping forces are applied by the clamping surface 366 substantially opposite the pivot arm 120. As will be described in greater detail below, these clamping forces may counteract opposing forces from adhesive pressure and pivot arm action that tend to force the dispensing module 16 and liquid supply component 312 apart. However, those skilled in the art will appreciate that attachment member 20 and/or recess 374 may be designed so that the clamping force is applied at any desired location along dispensing module body 316. Additionally, those skilled in the art will appreciate that attachment member 20 may be designed to apply the clamping force directly to the front surface 376 of dispensing module body 316. To this end, the dispensing module body 316 may or may not be designed with the recess 374.

[0073] As shown in Fig. 12, fastener 370 includes a shaft 394 extending through the fastener hole 368 and a head 372 configured to be retained against a seating surface 396 on the attachment member 20. A threaded insert 398 having female threads 400 configured to receive and engage male threads 402 on the shaft 394 is secured in the main body portion 324 of liquid supply component 312. The threaded insert 398 may be formed from a material stronger than that of the main body portion 324. For example, when the main body portion 324 is formed from aluminum, the threaded insert 398 may be formed from steel. Such an arrangement helps prevent deformation of the female threads 400, especially at elevated temperatures. The installation of the threaded insert 398 may be made possible by arcuate portions 404 (Fig. 10), which may be machined by a counter-boring process or otherwise formed in the channel 330. Additionally, the arcuate portions 404 may provide clearance for the head 372 of fastener 370, depending on which type of fastener is used. [0074] In alternative embodiments, female threads (not shown) could be directly formed, such as by tapping, into the main body portion 324 to receive and engage the male threads 402, if material properties and service requirements indicated that the female threads would perform satisfactorily. [0075] Referring to Figs. 9, 10, 12, and 13, one embodiment of an assembly and disassembly process and certain functional aspects of structural features previously described will now be explained.

[0076] Starting with Fig. 9, showing the dispensing module 16 assembled to the liquid suppiy component 312 and the attachment member 20 in a first position, and proceeding to Fig. 10, the fastener 370 is loosened so that the male threads 402 are disengaged from the female threads 400 in the liquid supply component 312. To provide rotational clearance, the fastener 370 is fully or partially removed from the attachment member 20, and the attachment member 20 is rotated about the pivot pin 334 to the second position. The dispensing module 16 may then be pulled away from the liquid supply component 312,

[0077] Referring to Fig. 12, the dispensing module 16 and the liquid supply component 312 are shown brought together with the fastener 370 retracted from the attachment member 20 in preparation for rotating the attachment member 20 into the recess 374. When the attachment member 20 is rotated to bring the projection 364 into engagement with the socket 384, the projection 364 may initially retain the dispensing module 16 in the proper position until the male threads 402 of the fastener 370 are brought into engagement with the female threads 400 of the threaded insert 398. Alternatively, the design of a protrusion and a socket may be reversed, with the attachment member 20 having a socket, and the dispensing module 16 having a protrusion, or any similar physical interaction of shapes couSd be used. Conventional dispensing modules and liquid supply components, without an attachment member, typically require the dispensing module 16 to be held while inserting a screw or other fastener through the dispensing module 16 to the liquid supply component 312.

[00783 Referring to Fig. 13, the attachment member 20 has been rotated into position, and the fastener 370 has been placed in tension to bring the head 372 into contact with the seating surface 396. The tension force in the fastener 370 is transformed by the head 372 and attachment member 20 into a compressive clamping force applied to the inlet surface 318 and front surface 326. Advantageously, applying the compressive clamping force substantially perpendicularly to the inlet surface 318 and front surface 326, and not laterally, heips evenly compress seals — such as a liquid iniet seal 406 {Fig. 11 ) around the liquid inlet 94 and the flexible seal 130 (Fig. 11 ) around the pivot arm 120— to maintain proper contact between the dispensing module 16 and liquid supply component 312. Failure to apply substantially perpendicular compressive forces may allow leakage, or may decrease the life of the liquid inlet seal 406 or the flexible seal 130. Furthermore, when the force is applied perpendicularly, it can best counteract the opposing forces from adhesive pressure and pivot arm action that tend to force apart the front surface 326 and the inlet surface 318. In this embodiment, to allow forceful contact between the clamping surface 366 and contact surface 390, other nearby surfaces, such as a bottom surface 408 of elongate section 358 and the bottom surface 362 of head section 360 do not contact the dispensing module body 316. It is appreciated by one skilled in the art that other designs could utilize intentional contact at the bottom surface 408 and/or bottom surface 362. [0079] As an alternative to the particular fastener system described in the embodiment of Figures 9-15, other simiiar fastener systems could be used. Examples of other systems include, without limitation: a stud with a nut or finger knob, a clamp, or any other structure that can apply a force to the attachment member 20 in a similar manner as the fastener 370. Additionally, rather than being pivotally coupied to the liquid supply component 312, the attachment member 20 may simply be coupled by the fastener 370 alone or in combination with another coupling technique.

[0080] With reference to Fig. 14, a cross-section of the apparatus 310 is shown. This figure shows an example of the many internal passages that are avoided by not having fasteners passing through dispensing module 16 (i.e., from front surface 376 to the inlet surface 318) and into liquid supply component 312. Indeed, the dispensing module body 316 need not include any holes extending from the front surface 376 to the inlet surface 318 for receiving a fastener.

[0081] With reference to Fig. 15, another embodiment of a dispensing apparatus 510 includes a dispensing module 516 coupled to a liquid supply component 512. The dispensing module 516 may be coupled to the liquid supply component 512 by the attachment member 20 in the same manner as the dispensing module 16 and the liquid supply component 312, respectively. Accordingly, like reference numbers will be used to refer to like structure from Figs. 9-14. In the dispensing apparatus 510, however, an adapter plate 518 is positioned between the dispensing module 516 and the liquid supply component 512. The adapter plate 518 may be removed simultaneously with dispensing module 516 when the attachment member 20 is in the appropriate position. As a result, the adapter plate 518 maintains the flexible seal 130 (Fig. 11 ) fully seated within the opening 320 during removal to prevent leakage between the dispensing module 516 and flexible sea! 130. The attachment member 20 may accommodate the adapter plate 518 by making appropriate design changes in the position of pivot pin 334, clamping surface 366 {Figs. 12- 14), or contact surface 390 (Figs. 12-14) so that the compressive damping forces remain substantially perpendicular to the inlet surface 318. However, even without exact accommodations, a proportion of clamping forces sufficient for the seals to function properly may still be available. [0082] Figs. 16A and 16B illustrate a dispensing module 616 and attachment member 620 according to another embodiment. The dispensing module 616 may be a conventional dispensing module having one or more holes 622 extending therethrough. The holes 622 are designed to accommodate fasteners (not shown) typically used to couple the dispensing module 616 to a liquid supply component (not shown). Normaily such fasteners include a head retained within a recess 642 and against a bottom surface 646 of the recess 642. However, rather than inserting such fasteners through the dispensing module 616, the attachment member 620 may be used to apply a clamping force to the dispensing module 616 in a manner similar to the attachment member 20 (Fig. 9).

[0083] For example, the attachment member 620 may be pivotally coupled to a liquid supply component in a manner similar to the attachment member 20. Because reference can be made to the description of attachment member 20 and liquid supply component 312 for a more complete understanding of such a coupling arrangement, a first portion of attachment member 620 and a liquid supply component are not shown in Figs. 16A and 16B. A second portion 626 of attachment member 620 may include an elongate section 628 and head section 630 arranged to provide the second portion 626 with a substantially T-shaped configuration, although other configurations are also possible. The elongate section 628 and head section 630 may have substantially the same thickness as shown, or may have different thicknesses ϋke the elongate section 358 and head section 360 of attachment member 20 (Figs. 10 and 12-14).

[0084] A bottom surface 632 defined by both the elongate section 628 and head section 630 confronts the dispensing module 616 when the attachment member 620 is moved into a position to apply the clamping force to the dispensing module 616. In some embodiments, the attachment member 620 may further include projections 640 extending from the bottom surface 632. The projections 640 may be received in the recess 642, which is defined across a front surface 644 of dispensing module 616, and the head section 630 may be shaped to substantially cover the recess 642. The projections 640 may be sized and shaped to contact the bottom surface 646 when the attachment member 620 is in the position shown in Fig. 16B.

[0085] Those skilled in the art will appreciate that there may be some embodiments in which the holes 622 include a counterbore (not shown) to accommodate the heads of the fasteners typically used to secure the dispensing module 616. The recess 642 may or may not be defined in the front surface 644 of dispensing module 616 in such embodiments. Additionally, the projections 640 may be sized and shaped to at least partially extend into the holes 622. For example, the projections 640 may be retained within the counterbores much like the heads of the fasteners typically used to secure the dispensing module 616. The number of projections 640 may therefore correspond to the number of holes 622 in the dispensing module 616. [0086] Fig. 17 illustrates an attachment member 720 according to yet another embodiment, with like reference numbers being used to refer to like structure from the embodiment in Figs. 16A and 16B. The attachment member 720 may be used to couple two or more of the dispensing modules 616 to a liquid supply component (not shown) in the form of a manifold or service block. Again, because a first portion of the attachment member 720 may be coupled to a liquid supply component in a manner similar to the attachment member 20, only a second portion 726 of attachment member 720 is shown. [0087] The second portion 726 may include an elongate section 728 and a head section 730 configured to extend across at least a portion of two or more of the dispensing modules 616. For example, the second portion 726 may have a T-shaped configuration with the head section 730 covering the recesses 642 and the elongate section 728 extending over the front surfaces 644 at an interface 734 between the dispensing modules 616. The attachment member 720 may also include projections 740 extending from a bottom surface 732 in a manner similar to the attachment member 620. Accordingly, the discussion above with respect to the projections 640 (Figs. 16A and 16B) applies equally to the projections 740,

[0088] While the invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, the attachment member 20 may alternatively include the fastener hole 368 in a portion extending beyond the pivot hole 356, thus making the pivot pin 334 into a fulcrum on which the attachment member 20 pivots, in such an example (not shown), a fastener or other device could be used in compression, rather than tension, to create a force at the clamping surface 366 that wouid push the dispensing module 16 against the liquid supply component 312. [0089] Additionally, although the attachment member 20 is shown as being coupled to the front body portion 328 of liquid supply component 312, other arrangements are possible in which the attachment member 20 may be coupied to a separate component (not shown) mounted on, attached, or otherwise secured to the liquid supply component 312. Such an arrangement allows conventional liquid supply components to be modified to utilize the attachment members 20, 620, and 720 regardless of whether liquid supply components are designed with front body portion 328. To this end, those skilled in the art will appreciate that the attachment members described above may be part of an attachment system that includes a stationary component, which may be a portion of a liquid supply component {such as the front body portion 328 of liquid supply component 312) or a separate component secured to a liquid supply component to form an assembly.

[0090] Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept. What is claimed is:

Claims

1. An actuating assembly for a liquid dispensing apparatus, comprising: a housing including a piston chamber, a piston configured to reciprocate within said piston chamber along a piston axis, and an opening extending into said piston chamber and configured to receive a portion of a pivot arm, said piston configured to be coupled to a first end of the pivot arm so that said piston can drive a valve element coupled to a second end of the pivot arm within a dispensing module; and a three-way solenoid valve operatively coupled to said housing and having an inlet port for receiving pressurized air, a first outlet port communicating with said inlet port, a second outlet port selectively communicating with said inlet port, and an exhaust port selectively communicating with said second outlet port.

2. The actuating assembly of claim 1 wherein said solenoid valve is operatively coupled to said housing along said piston axis.

3. The actuating assembly of claim 1 wherein said solenoid valve further includes a poppet movable between a first position and a second position, said first outlet port communicating with said inlet port when said poppet is in said first position and said second position, said second outlet port communicating with said inlet port when said poppet is in said second position, and said exhaust port communicating with said second outlet port when said poppet is in said first position.

4. The actuating assembly of claim 3 wherein said poppet of said solenoid valve Is movable along an axis generally transverse to said piston axis.

5. The actuating assembly of claim 1 wherein said piston further includes a piston head seaiingly engaging said piston chamber, said piston head having a top surface and a bottom surface, said first outlet port being configured to direct pressurized air to said bottom surface, and said solenoid valve being configured to selectively direct pressurized air through said second outlet port and to said top surface to operate said piston.

6. The actuating assembly of claim 5, further comprising: a thermal isolator positioned between said solenoid valve and said housing, said thermal isolator being formed from a thermally insulating material to reduce heat transfer from said housing to said solenoid valve.

7. The actuating assembly of claim 6 wherein said thermal isolator further includes a first passage extending from said first outlet port of said solenoid valve to a portion of said piston chamber communicating with said bottom surface of said piston head, a second passage extending from said second outlet port of said solenoid valve to a portion of said piston chamber communicating with said top surface of said piston head, and a third passage configured to direct pressurized air from said exhaust port of said solenoid valve to outside said thermal isolator.

8. The actuating assembly of claim 1 wherein said solenoid valve further includes an outer body having fins configured to dissipate heat transferred to said solenoid vatve.

9. The actuating assembly of claim 1 wherein said piston within said housing comprises a piston head, an intermediate portion extending from said piston head, and a piston shaft extending from said intermediate portion, said piston head and said intermediate portion each having a seal adapted to sealingly engage said piston chamber, said piston chamber having a bearing surface adapted to guide said piston shaft as said piston moves within said piston chamber.

10. An apparatus for dispensing an adhesive, comprising: a dispensing module having a liquid inlet, a liquid passage in communication with said liquid inlet, an outlet in communication with said liquid passage, and a valve element movable within said liquid passage to selectively allow and prevent flow of the adhesive through said outlet; a pivot arm extending into said dispensing module and coupled to said valve element; and an actuating assembly, comprising: a housing proximate said dispensing module, said housing including a piston chamber and a piston configured to reciprocate within said piston chamber along a piston axis, said housing having an opening configured to receive a portion of said pivot arm, said piston being operatively coupled to said valve element by said pivot arm; and a three-way solenoid valve operatively coupled to said housing and configured to operate said piston, said solenoid valve having an inlet port for receiving pressurized air, a first outlet port communicating with said inlet port, a second outlet port selectively communicating with said inlet port, and an exhaust port selectively communicating with said second outlet port.

1 1 . The apparatus of claim 10 wherein said solenoid valve is operativeiy coupled to said housing along said piston axis.

12. The apparatus of claim 10 wherein said solenoid valve further includes a poppet movabie between a first position and a second position, said first outlet port communicating with said inlet port when said poppet is in said first position and said second position, said second outlet port communicating with said inlet port when said poppet is in said second position, and said exhaust port communicating with said second outlet port when said poppet is in said first position.

13. The apparatus of claim 12 wherein said poppet of said solenoid valve is movabie along an axis generally transverse to said piston axis.

14. The apparatus of claim 10 wherein said piston further includes a piston head sealingiy engaging said piston chamber, said piston head having a top surface and a bottom surface, said first outlet port being configured to direct pressurized air to said bottom surface, and said solenoid valve being configured to selectively direct pressurized air through said second outlet port and to said top surface to operate said piston.

15. The apparatus of claim 14, further comprising: a thermal isolator positioned between said solenoid valve and said housing, said thermal isolator being formed from a thermally insulating materia! to reduce heat transfer from said housing and said dispensing module to said solenoid valve.

16. The apparatus of claim 15 wherein said thermal isolator further includes a first passage extending from said first outlet port of said solenoid valve to a portion of said piston chamber communicating with said bottom surface of said piston head, a second passage extending from said second outlet port of said solenoid valve to a portion of said piston chamber communicating with said top surface of said piston head, and a third passage configured to direct pressurized air from said exhaust port of said solenoid valve to outside said thermal isolator.

17. The apparatus of claim 10 wherein said solenoid valve further includes an outer body having fins configured to dissipate heat transferred to said solenoid valve.

18. The apparatus of claim 10 wherein said piston within said housing comprises a piston head, an intermediate portion extending from said piston head, and a piston shaft extending from said intermediate portion, said piston head and said intermediate portion each having a seal adapted to sealingly engage said piston chamber, said piston chamber having a bearing surface adapted to guide said piston shaft as said piston moves within said piston chamber.

19. An apparatus for dispensing an adhesive, comprising: a dispensing module having a liquid inlet, a liquid passage in communication with said liquid inlet, and an outlet in communication with said liquid passage, said dispensing module further including a valve element movable within said liquid passage to selectively allow and prevent flow of the adhesive through said outlet; a liquid supply component coupled to said dispensing module and having a supply passage for directing adhesive to said liquid inlet; a pivot arm extending into said dispensing module and coupled to said valve element; and an actuating assembly, comprising: a housing at least partially received in said liquid supply component, said housing including a piston chamber and a piston configured to reciprocate within said piston chamber along a piston axis, said housing having an opening configured to receive a portion of said pivot arm, said piston being operatively coupled to said valve element by said pivot arm; and a three-way solenoid valve operatively coupled to said housing along said piston axis and configured to operate said piston, said solenoid vaive having an inlet port for receiving pressurized air, a first outlet port communicating with said inlet port, a second outlet port selectively communicating with said inlet port, and an exhaust port selectively communicating with said second outlet port.

20. The apparatus of claim 19 wherein said liquid supply component defines a recess and said housing is at least partially received within said recess.

21. The apparatus of claim 20 wherein said housing including a reduced diameter section defining a portion of said supply passage so that adhesive can fiow around said housing between said reduced diameter section and said liquid supply component.

22. The apparatus of claim 19, further comprising: a plurality of said dispensing modules each coupied to said liquid supply component, said liquid supply component having a plurality of supply passages for directing adhesive to said plurality of dispensing modules; a plurality of said pivot arms corresponding to said plurality of dispensing modules; and a plurality of said actuating assemblies corresponding to said plurality of dispensing modules and said plurality of pivot arms.

23. The apparatus of claim 22 wherein at least one of said housings includes a reduced diameter section defining a portion of one of said supply passages so that adhesive can flow around said at least one housing between said reduced diameter section and said liquid supply component.

24. An apparatus for dispensing an adhesive, comprising: a dispensing module having a liquid inlet, an internal passage communicating with said liquid inlet, an outlet communicating with said internal passage, and a valve element movable within said internal passage to selectively allow and prevent flow of adhesive through said outlet; and an attachment system, including: a stationary component; and an attachment member having a first portion pivotally coupled to said stationary component and a second portion configured to apply a clamping force to said dispensing module to couple said dispensing module to said stationary component.

25. The apparatus of claim 24 wherein said attachment member further includes an opening extending through said first portion and said attachment member is movable between a first position in which said attachment member applies the clamping force and a second position in which said attachment member allows said dispensing module to be moved away from said stationary component, said stationary component including a hole configured to engage a fastener after the fastener is inserted through said opening of said attachment member when said attachment member is in said first position.

26. The apparatus of claim 24 wherein said dispensing module includes a recess configured to at least partially receive said second portion of said attachment member.

27. The apparatus of claim 26 wherein said second portion of said attachment member includes an elongate section and a head section, said head section defining a bottom surface and at least one projection extending from said bottom surface, said at least one projection having a clamping surface configured to contact the dispensing module.

28. The apparatus of claim 27 wherein said recess includes a first section shaped to accommodate said eiongate section of said attachment member and a second section shaped to accommodate said head section of said attachment member.

29. The apparatus of claim 27 wherein said elongate section and said head section are configured to provide said second portion with a substantially T-shaped configuration, said dispensing module including a front face with said recess extending across said front face, and said head section being configured to cover at least a portion of said recess.

30. The apparatus of claim 24 wherein said dispensing module includes at least one hole normally configured to receive a fastener and said second portion of said attachment member includes a bottom surface and at ieast one projection extending from said bottom surface, said at least one projection configured to at ieast partially extend into said at least one hole when said attachment member applies the clamping force to said dispensing module.

31. The apparatus of claim 24, further comprising: a liquid supply component configured to supply the adhesive to said liquid inlet, wherein said stationary component is secured to said liquid supply component to form an assembly.

32. The apparatus of claim 24, further comprising: a liquid supply component configured to supply the adhesive to said liquid inlet, wherein said stationary component is formed integrally with said liquid supply component.

33. The apparatus of claim 32, further comprising: an adapter plate positioned between said dispensing module and said liquid supply component, said attachment member being configured to securely retain said dispensing module against said adapter plate.

34. The apparatus of claim 24 wherein said liquid inlet is located on an inlet surface of said dispensing module, said attachment member being configured to apply the clamping force to said dispensing module in a direction substantially perpendicular to said inlet surface.

35. The apparatus of claim 24, further comprising: at least one additional dispensing module; and at least one additional attachment system corresponding to said at least one additional dispensing module.

36. The apparatus of 24, further comprising: at least one additional dispensing module, said second portion of said attachment member configured to extend across portions of at least two of said dispensing modules so that said attachment member is configured to apply a clamping force to said at least two dispensing modules.

37. The apparatus of claim 36 wherein said second portion of said attachment member includes an elongate section and a head section configured to provide said second section with a substantially T-shaped configuration, said head section being configured to extend across said at least two dispensing modules.

38. An apparatus for dispensing an adhesive, comprising: a dispensing module; a liquid supply component configured to supply the adhesive to said dispensing module; and an attachment system, including: a stationary component; and an attachment member having a first portion pivotally coupled to said stationary component, an opening extending through said first portion and configured to receive a fastener, and a second portion configured to apply a clamping force to said dispensing module to couple said dispensing module to said stationary component.

39. The apparatus of claim 38 wherein said stationary component is formed integrally with said liquid supply component.

40. An attachment system for a liquid dispensing apparatus, comprising: a stationary component; and an attachment member having a first portion pivotally coupled to said stationary component, an opening extending through said first portion and configured to receive a fastener, and a second portion configured to apply a damping force to a dispensing module to couple the dispensing moduϊe to said stationary component.

41. The attachment system claim 40 wherein said attachment member is movable between a first position in which said attachment member appiies the clamping force and a second position in which said attachment member allows the dispensing module to be moved away from said stationary component, said stationary component including a hole configured to engage the fastener after the fastener is inserted through said opening of said attachment member when said attachment member is in said first position.

42. The attachment system of claim 40 wherein said second portion of said attachment member includes an elongate section and a head section, said head section defining a bottom surface and at least one projection extending from said bottom surface, said at least one projection having a clamping surface configured to contact the dispensing module.

43. The attachment system of claim 42 wherein said elongate section and said head section form a substantially T-shaped configuration.

44. A dispensing module for dispensing an adhesive, wherein the dispensing module is configured to be coupled to a liquid supply component by an attachment member having a head section and an elongate section, the dispensing module comprising: a body having a top surface, a front surface, an inlet surface opposite said front surface, a liquid inlet on said inlet surface, an internal passage communicating with said liquid inlet, an outlet communicating with said internal passage, and a valve element movable within said internal passage to selectively allow and prevent flow of the adhesive through said outlet, said front surface defining a recess including a first section extending downwardly from said top surface and shaped to accommodate the elongate section of the attachment member and a second section shaped to accommodate the head section of the attachment member.

45. The dispensing module of claim 44 wherein at least a portion of said first section of said recess has a first depth relative to said front surface and at least a portion of said second section has a second depth greater than said first depth so as to define an overhang in said recess.

46. The dispensing module of claim 45 wherein said first section of said recess is tapered so as to decrease in depth in a direction extending downwardly from said top surface.

47. The dispensing moduie of ciaim 46 wherein said second section of said recess includes a socket defined by a substantially cylindrical surface extending to a contact surface located at said second depth.

48. The dispensing module of claim 44 wherein said body further includes at least one of: (a) an opening on said inlet surface configured to receive a pivot arm for actuating said valve element in said interna! passage, said second section of said recess and said opening being substantially aligned along a common axis; or (b) a channel defined in said inlet surface and configured to register with a similarly shaped projection on the liquid supply component.

49. A method of releasably attaching a dispensing module to a liquid supply component, comprising: moving an attachment member from a first position to a second position, the attachment member being pivotally coupled to the liquid supply component; positioning the dispensing module in a desired position relative to the liquid supply component when the attachment member is in the second position, the dispensing module having a liquid inlet, an internal passage communicating with the liquid inlet, an outlet communicating with the internal passage, and a valve element movable within the internal passage; and moving the attachment member from the second position to the first position to retain the dispensing module in the desired position.

50. The method of claim 49 wherein the attachment member includes a first portion pivotally coupled to the liquid supply component and a second portion configured to apply a clamping force to the dispensing module, and wherein moving the attachment member from the second position to the first position comprises: rotating the second portion of the attachment member into a recess defined in a front surface of the dispensing module.

51 . The method of claim 49, further comprising: inserting a fastener through an opening in the attachment member and into a hole in the liquid supply component, wherein the fastener includes a head larger than a diameter of the opening so as to be retained by the attachment member; and rotating the fastener to engage internal threads in the hole of the liquid supply component and thereby cause the attachment member to apply a clamping force to the dispensing module.

52. The method of ciaim 49 wherein the dispensing module has an iniet surface configured to be positioned proximate the liquid supply component, the method further comprising: applying a clamping force to the dispensing module with the attachment member in a direction substantially perpendicular to the inlet surface.

53, The method of claim 49, further comprising: supplying adhesive to the dispensing module from the liquid supply component; dispensing the adhesive from the dispensing module; moving the attachment member from the first position to the second position after the adhesive has been dispensed; and moving the dispensing module away from the liquid supply component.

54, A method of releasably attaching a dispensing module to a liquid supply component, comprising: positioning the dispensing module in a desired position relative to the liquid supply component; positioning an attachment member relative to the dispensing module and the liquid supply component, the attachment member including a first portion configured to confront the liquid supply component, an opening extending through the first portion, and a second portion configured to confront the dispensing module; inserting a fastener through the opening in the attachment member and into a hole provided in the liquid supply component; and rotating the fastener in a first direction to engage internal threads in the hole of the liquid supply component, the fastener including a head retained against the attachment member so that the second portion of the attachment member applies a clamping force to the dispensing module when the fastener is sufficiently rotated.

55. The method of claim 54 wherein the first portion of the attachment member is pivotaliy coupied to the liquid supply component, the attachment member being movable from a first position to a second position, and wherein positioning the attachment member relative to the dispensing module and the liquid supply component comprises: rotating the attachment member from the second position to the first position.

56. The method of claim 55 wherein rotating the attachment member from the second position to the first position comprises: rotating the second portion of the attachment member into a recess defined in the dispensing module.

57. The method of claim 55 wherein the attachment member initially retains the dispensing module in the desired position when rotated into the first position.

58. The method of claim 55, further comprising: rotating the fastener in a second direction to disengage the internal threads from the hole of the liquid supply component; rotating the attachment member from the first position to the second position; and moving the dispensing module away from the liquid supply component.