DE202014101769U1 - Thermal switching element and contact element - Google Patents

Abstract

Thermal switching device, in particular temperature controller, temperature limiter, temperature monitor or temperature fuse, for connection to a heating device (14) of a utility object, wherein the thermal switching device is in thermal contact with the heating device (14), with a first and second connection (5, 6), Preferably plug-in connection, for connecting the thermal switching device to an electrical circuit, a temperature-responsive functional element, preferably a bimetallic element or a fusible element, to ensure a temperature-dependent switching function of the thermal switching device for interrupting the electrical circuit, characterized in that at least one terminal (5 , 6) a resilient contact extension (8, 9) is provided.

Description

The present invention relates to a thermal switching device according to the preamble of claim 1 and a contact element for use in a thermal switching element.

Technological background

Thermal switching devices of the type of interest are, in particular, temperature regulators, temperature limiters, temperature monitors or temperature protectors, which are in thermal contact with the heating device of a consumer product and automatically execute a switching operation when a predetermined temperature threshold value is exceeded. In particular, such thermal switching devices are commonly used in commodities, e.g. Kettle, water heater, coffee machines, washing machines, dishwashers, steamer, iron and the like used.

In the case of temperature regulators, the active component used here is usually a bimetallic snap disk which assumes two stable snap positions (deflections) as a function of temperature (bistable snap-action bimetal disc) and depending on their respective deflection, opens or closes a circuit. In a thermal fuse is used as the active component instead of the bimetallic snap a melting device z. B. enamel pellet, by means of which when a temperature is exceeded, a circuit can be interrupted.

A corresponding thermal switching device in the form of a thermal temperature controller and a thermal thermal fuse is for example from DE 197 06 316 C2 seen.

Nowadays, so-called thick-film heaters are increasingly being used as heaters. This heating cables are on a substrate z. As a substrate made of metal or ceramic, printed. Such a thick film heater can e.g. be used as a hotplate for a kitchen mixer or the like. Thick film heaters have the advantage of a small footprint, above all. Due to their usually high heating speed, they require particularly good thermally connected, rapidly reacting control and safety components. A particularly good thermal connection of the active components of thermal switching devices of the aforementioned type to such a thick-film heating is therefore a new challenge. Internal experiments have shown that the production of a fixed connection of the contact of a thermal switching device with a contact of the thick-film heating by soldering problematic is because due to the introduced in the operation of temperature fluctuations mechanical stresses may occur that the solder joints solve and thus no longer sufficient temperature control or thermal fuse can be done.

Object of the present invention

The object of the present invention is to provide a novel thermal switching device of the generic type and a contact element suitable for this purpose, which permanently ensure reliable contact of the thermal switching device for thick-film heating even when occurring during operation temperature fluctuations.

Solution of the task

The above object is achieved in the generic thermal switching device in that at least at one terminal, preferably at both terminals, in addition a resilient contact extension is provided. The resilient contact extension makes it possible to contact the respective terminal of the thermal switching device, which is usually a laterally positioned on the thermal switching device outwardly projecting flat contact of a metallic contact material without spring action, by pressing against the open contacts of a thick film heater. As a result, a permanently reliable connection of the thermal switching device to the thick-film heater is made possible even at considerable temperature-implicated voltages. At the same time, the invention also makes it possible to retrofit conventional thermal switching devices in a simple manner with the resilient contact extension.

The contact extension is preferably oriented from the electrical connection of the thermal switching device down in the direction of the bearing surface of the housing of the thermal switching device and bridges in this way the distance between two contact terminals located on the underside of the thermal switching device thick film heater. This allows conventional thermal switching devices to be readily used for use in conjunction with thick film heating.

Due to the fact that the contact extension projects beyond the underside of the thermal switching device or its bearing surface, a contact pressure of the thermal switch device can be applied to the thick-film heating during assembly Contact extension can be generated on the top side, open contacts of the thick film heater. Due to this contact pressure, an effective contact is permanently achieved even when temperature-induced voltage occurs.

According to an expedient embodiment of the present invention, the contact extension at the bottom of the terminal, for example, by a laser welding connection, electric welding connection, solder connection, permanently attached.

Alternatively, the contact extension can also be detachably connected, in particular attachable, to the free end of the connection.

For example, this may be provided on the contact extension plug-in shoe in the manner of a cable lug, so that corresponding contact extensions can also be attached to finished components later.

The plug-in shoe can be connected to the cable extension via a welded connection, for example via laser welding points.

Conveniently, the contact extension is designed as a leaf spring. Through the flat upper portion, which is preferably positioned at the bottom of the terminal, the total thickness of the terminal is only slightly increased, which brings with it the advantage that a conventional plug-in shoe for electrical contact can still be plugged. Further, a leaf spring has the advantage of being able to produce the contact extension in a simple manner by flat material is folded in the desired manner.

In the case of a leaf spring, moreover, a plug connection in the manner of a cable lug can be realized in a particularly simple manner by receiving channels which are bent laterally at the upper region.

According to an alternative embodiment may be used as a contact extension and a spring contact pin.

According to a further alternative embodiment, the contact extension can be fixed in its position in that the latter is inserted into a housing or housing part which engages over the connection. As a result, even a loose contact element can be used as a contact extension, which is positioned simultaneously on the thick film heater only by the assembly of the thermal switching device or its housing part.

The bulge at the end region of the contact extension, where the contact extension comes into electrical contact with the open contact of the thick film heater, ensures the advantage that even at temperature-induced voltages the contact can make a rolling movement over the contour of the bulge.

Appropriately, the bulge is realized by an impression. As a result, for example, a spherical segment bulge can be achieved.

The invention mentioned above is achieved in the contact element according to the preamble of claim 13, characterized in that the contact element is designed as a resilient contact extension for the connection of the thermal switching device.

Preferably, the resilient contact extension is designed as a leaf spring. According to an expedient embodiment of the contact element according to the invention, the resilient contact extension has a first angled contact region, which is intended to come into contact with the open contact on the thick film heater.

Conveniently, the resilient contact extension may preferably have a bulge in the first angled contact area, which allows a rolling behavior of the contact at the occurrence of temperature-induced voltages.

In order to simplify a fixation of the contact element to the connection of the thermal switching device, a second angled region is provided, which is preferably formed flat. This allows a permanent connection, such as welding by laser welding or arc welding or the like. The contact element then has an open, C-like shape.

Alternatively, the contact element may also have a closed shape, namely when the top-side connection region is formed by both free ends of the contact element. The contact element then has a closed in the bridging region, Ω-like shape.

The upper-side connection region is preferably dimensioned such that it does not protrude beyond the connection of the thermal switching device laterally and / or at its free end, or at least approximately terminates flush with the connection. It can thereby conventional Plug can be used without this requires an adjustment.

Likewise, a second angled end portion of the contact extension, the contact element may be equipped with the plug-in receptacle or a plug-in shoe, which allows a plug connection of the contact extension with the connection of the thermal switching device.

If the resilient contact extension is merely inserted into a housing and a contact is ensured at both end regions of the contact extension due to the contact pressure of the resilient contact extension, it is expedient if the second angled region also has a bulge.

The fact that the contact extension has at least one, preferably a plurality of holding projections, the latter can be securely positioned, especially if the contact extension is loosely inserted into a housing part and the contact takes place exclusively by a contact pressure both at one end and at the other end of the contact extension ,

Conveniently, the retaining projections are retaining wings, which can be formed from the leaf spring by a simple punching operation and slightly angled.

Description of the invention with reference to embodiments

Advantageous embodiments of the present invention will be explained in more detail with reference to embodiments. Show it:

1 a first embodiment of a thermal switching device according to the present invention in the form of a temperature fuse in a simplified perspective view with a view obliquely from above;

2 a simplified perspective view of the thermal switching device according to 1 with view obliquely from below;

3 a further embodiment of a thermal switching device according to the present invention in the form of a temperature controller in a simplified side view;

4A a greatly simplified perspective view of a thermal switching device according to the invention in a built-up with a thick-film heating state with two spring terminals;

4B a greatly simplified perspective view of a thermal switching device according to the invention in a built-up with a thick-film heating state, each with a single spring connection;

5A a simplified perspective view of an expedient embodiment of a contact element according to the present invention;

5B a simplified perspective view of another useful embodiment of a contact element according to the present invention;

6 a simplified perspective view of another expedient embodiment of a contact element according to the present invention for retrofitting conventional thermal switching devices;

7 a further embodiment of a contact element for retrofitting conventional thermal switching devices;

8th a further embodiment of a contact element for retrofitting conventional thermal switching devices;

9 an exemplary embodiment of a thermal switching device with a retaining clip and a common housing addition and

10 a further exemplary embodiment of a thermal switching device with a contact element with a closed shape.

1 shows a thermal switching device according to the present invention in the form of a thermal fuse 1 , The temperature fuse 1 includes a housing 3 , preferably ceramic housing, and a plate-shaped carrier 7 that's the case 3 wearing. Inside the case 3 there is a melting pill 4 , which ensures a break in the electrical connection when a certain predetermined temperature is exceeded.

At the top of the case 3 For example, there are two electrical connections 5 . 6 which serve to integrate the thermal switching device in an electrical circuit. Depending on whether the fuse has switched, the circuit is either closed or open. The temperature fuse 1 , which is usually located in the range of a heater or a medium to be heated, has a special switching characteristic for protection.

According to the invention has temperature fuse 1 at least in the region of a connection, preferably in the region of both connections 5 . 6 , a resilient contact extension 8th . 9 on. The contact extension 8th . 9 is at the in 1 shown representation down to the support surface A of the thermal fuse 1 oriented and thus bridges the distance between the respective contact connection 5 respectively. 6 and the top of the support surface A of the thermal fuse 1 ,

At the in 1 illustrated embodiment is the resilient contact extension 8th . 9 configured as a double-angled leaf spring. It has an upper end area as connection area 19 . 20 on, which is parallel to the respective connection 5 . 6 is oriented. The the top end area 19 . 20 opposite lower end region is also formed as an area of contact angled and serves with an open contact of a thick-film heater (see. 4A or 4B ) to contact. The lower end portion may be angled to the central region at an angle greater than 90 ° to ensure a spring-induced contact pressure.

In the lower part of the contact extension 8th . 9 may suitably a bulge 13 . 14 be provided, which serves to facilitate a lighter rolling movement of the contact to the opposite contact surface of the thick film heater at temperature-induced voltages. The bulge 13 . 14 preferably has a spherical segmental shape. In a contact extension consisting of a leaf spring 8th . 9 This can be imprinted in a simple manner. Between the lower part of the contact extension 8th . 9 and the perpendicular center portion thereof has a radius of curvature greater than the radius of curvature between the top end portion 19 and 20 and the vertical portion of the contact extension 8th . 9 ,

Conveniently, the contact extension in the connection area so in the upper end 19 . 20 dimensioned so that the latter does not exceed the outer edge area of the terminal 5 . 6 outward and / or forward protrudes. This can be at the in 1 illustrated embodiment of the thermal switching device in a simple manner a conventional electrical plug-in element on the respective connection 5 . 6 be plugged. Thus, conventional plugs can be used without the need for adaptation.

As in 2 the respective contact extension can be seen 8th . 9 dimensioned so that the contact area so the lower portion thereof slightly above the support surface A of the thermal switching device 1 survives, whereby an advantageous Anpresscharakteristik is created as soon as the thermal switching device rests immovably mounted on the surface of a thick film heater. How out 2 also can be seen, the respective contact extension 8th . 9 with the respective connection 5 . 6 the thermal switching device be permanently connected. This can be done for example by means of a laser spot welding z. B. done in the form of one or more welds. An attachment point of the laser spot welding is in the 2 by way of example schematically 15 respectively. 16 characterized.

3 shows a thermal switching device according to the invention, in which instead of a thermal fuse 1 a temperature controller 2 each with a corresponding contact extension 8th . 9 Is provided. The temperature controller 2 also includes, analogous to the thermal fuse 1 , z. B. two connections 5 . 6 , on the underside of which the respective contact extension 8th and 9 is attached in the manner described. With regard to the design and dimensioning of the contact extension 8th and 9 can be made to the above statements. The temperature controller 2 owns instead of the enamel pill 4 the temperature fuse 1 from 1 respectively. 2 a bimetal functional part 18 18 for example, in the form of a bimetallic disc, which has two stable snap points depending on the ambient temperature. As with the temperature controller 2 an immediate switching is to occur upon reaching the fixed predetermined temperature is at the bottom of the controller 2 only a carrier 7 provided in the form of a very thin plate. In a recess of this plate is the bimetallic disc. The bimetal disc is thus in direct contact with the thick-film heating, which causes a particularly rapid thermal switching behavior.

4A shows in a highly simplified schematic representation of a temperature controller 2 on a thick film heater 10 , which has a plate-shaped substrate, for example made of metal (provided with an electrically insulating intermediate layer, eg enamel or screen-printed glass ceramic) or ceramic or the like, on the individual Heizleiterbahnen 11 applied, preferably printed. The heating conductors 11 are each via a connecting wire 12 contacted with a (not shown) electrical power supply. At the for the regulator 1 or the fuse 2 provided point are in this embodiment of thick-film heating the Heizleiterbahnen 11 interrupted to a regulator 1 or a fuse 2 to be able to switch on in the conductor track circle. For this purpose, the temperature controller 1 or the temperature fuse 2 on the thick film heater 10 positioned, for example by a (not shown) holding device and the two terminals 5 . 6 about the contact extensions 8th . 9 with the open Contact points of the heating conductor 11 connected. Here are the lower end portions of the contact extensions 8th . 9 loose on the open contacts of the heating conductor and ensure bridging the otherwise open electrical current path. The embodiment has the advantage that nonetheless a durable active contacting and thus a reliable operation can be ensured when temperature-induced fluctuations occur.

The attachment of the thermal switching device on the thick film heater 10 For example, by a in 4A not shown holding part, by means of which the thermal switching device on the support surface to the top of the thick film heater 20 pressed and held in a non-moving position done.

For thick film heating 10 to 4B is the respective end of the heating conductor 11 each with a thermal switching element z. B. in the form of a temperature controller 2 connected. As a result, there is only one connection each 5 the relevant temperature controller 2 via a contact extension 8th with the end of the heating conductor 11 in contact, whereas the further connection 6 of the temperature controller 2 an electrical contact with the respective connecting wire 12 guaranteed. Thus, in this arrangement can be dispensed with an additional contact terminal for power connection. This in turn can reduce the susceptibility of the electrical contact connection to failure.

Alternatively to the representations in the 4A such as 4B The Heizleiterbahnen can also run under the thermally sensitive parts of the respective thermal switching device. As a result, the response times or trip times can be greatly reduced.

The representation after 5A shows the contact extension 8th in the state before mounting on the connector 5 the thermal switching device 1 respectively. 2 the embodiments according to 1 - 3 , The contact element is made from a leaf spring made of metal (spring steel), bent at two positions and preferably by an embossing process with a bulge 13 in the lower, the contact area forming end portion of the contact extension 8th Mistake. The upper end area 19 . 20 is flat, so that it is flat at the bottom of the respective connection 5 . 6 can be created and connected to the latter there.

When in the 5B illustrated variant of a resilient contact extension is a contact element variant also made of a leaf spring material, which closed in the lower area and at the top two mutually oriented connection areas for attachment to the respective connection 5 respectively. 6 the thermal switching device 1 respectively. 2 having. In the lower area can also be a bulge 13 be provided. This variant of the contact element ensures increased spring action due to its closed state in the assembled state. Also, this contact spring is preferably in the state attached to the thermal switching element on mental extension of the horizontal support surface A (see, eg 1 ) down over. This embodiment of the contact element has a closed shape in which the two open end portions of the contact extension to form a butt joint 28 the top contact area with the connector 5 respectively. 6 form.

In the embodiment according to 6 is the upper end area 19 the contact element preferably integrally on both sides with receiving channels 21 Mistake. The upper end area 19 thus forms a kind of plug-in shoe. The recording channels 21 can be particularly easily introduced in a leaf spring material by a kind of flanging.

In the embodiment according to 7 Alternatively, as a contact extension is a resilient contact pin 25 used. This can with a corresponding upper part as with 6 be connected.

The 8C shows a further embodiment of a resilient contact extension 9 in the form of a contact element according to the present invention. The contact element is constructed from a leaf spring and comprises both at the top and at the bottom depending on a contact area with a bulge 13 , Both contact areas only contact by contact pressure, one contact area contacts the terminal of the thermal switching element, the other contact area contacts the open contact of the heat conductor track of the thick film heater (see, for example, US Pat. 4a such as 4b ). The holder of the contact element ensures the housing 3 or a housing addition 25 , the or the contact element, see. Bottom view with contact element according to 8B , at least partially encloses and thereby holds in position. The contact element is prior to assembly, see. Bottom view without contact element 8A from below, in through the housing 3 or housing part 25 as well as the connection 6 formed bag 26 inserted and then held on fixing the thermal switching device on the support surface in position. For fixing the contact element, this two laterally arranged retaining wings 23 . 24 have, z. B. on housing webs 17 of the housing or housing part 25 attack.

The 9A such as 9B show a possibility of fixing a thermal Switching element according to the present invention on a in 9A respectively. 9B Thick film heater, not shown. In the embodiment, for example, two temperature controllers 2 in a common additional housing 25 accommodated, which means z. B. a strap 27 is attached to the top of the thick film heater. The coat hanger 27 For this purpose, for example, welded at its two ends on the top of the thick film heater. The two temperature controllers are connected to their terminals 6 with one in each 9A respectively. 9B Not shown connecting wire according to the embodiment of 4B connected. In the two in the area of the opposite connections 5 located bags 26 be (in 9A respectively. 9B not shown) resilient contact extensions of the kind as in 8C are shown, inserted and over the mounted additional housing 25 kept in position.

The 10A such as 10B show the use of a contact element with a closed shape, as in 5B is shown. Again, as in the embodiment of the 9A such as 9B for example, two temperature controllers 2 in a common additional housing 25 are housed, which by means of a bracket 27 is mounted on the top of a thick film heater, not shown. In this embodiment of the common additional housing 25 The latter only covers the upper-side area of the two temperature controllers 2 from. The coat hanger 27 is designed here as a circumferential frame. The resilient contact elements 8th are with their two open ends in the connection area with the connection 5 forming a contact joint 28 attached. The respective contact element thereby has a closed, Ω-like shape. Again, bulges can 13 be provided to improve the Abrollvorgangs in the contact area on the thick film heater.

LIST OF REFERENCE NUMBERS

1

 Thermal fuse

2

 thermostat

3

 casing

4

 melting pill

5

 connection

6

 connection

7

 carrier

8th

 contact spring

9

 contact spring

10

 Thick film heating

11

 conductor path

12

 Lead wire

13

 bulge

14

 bulge

15

 attachment point

16

 attachment point

17

 housing web

18

 Bimetallfunktionsteil

19

 End area above

20

 End area above

21

 receiving channel

22

 housing part

23

 retaining wings

24

 retaining wings

25

 additional housing

26

 bag

27

 hanger

28

 butt joint

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19706316 C2 [0004]

Claims (25)

Thermal switching device, in particular temperature controller, temperature limiter, temperature monitor or temperature fuse, for connection to a heating device ( 14 ) of an article of daily use, wherein the thermal switching device with the heating device ( 14 ) is in thermal contact with first and second terminals ( 5 . 6 ), preferably plug-in connection, for connecting the thermal switching device to an electrical circuit, a temperature-responsive functional element, preferably a bimetallic element or a fusible element, to ensure a temperature-dependent switching function of the thermal switching device for interrupting the electrical circuit, characterized in that at least one connection ( 5 . 6 ) a resilient contact extension ( 8th . 9 ) is provided. Thermal switching device according to claim 1, characterized in that the contact extension ( 8th . 9 ) down in the direction of support surface A of the housing ( 3 ) and the distance between connection ( 5 respectively. 6 ) and bearing surface A bridged. Thermal switching device according to claim 1 or 2, characterized in that the contact extension ( 8th . 9 ) beyond the mental extension of the horizontal bearing surface A also protrudes downwards. Thermal switching device according to at least one of the preceding claims, characterized in that the contact extension ( 8th . 9 ) at least one upper-side end region ( 19 . 20 ) parallel to the terminal ( 5 . 6 ) runs. Thermal switching device according to at least one of the preceding claims, characterized in that the contact extension ( 8th . 9 ), at the bottom of the connector ( 5 respectively. 6 ) is permanently attached. Thermal switching device according to at least one of claims 1 to 4, characterized in that the contact extension ( 8th . 9 ) with the free end of the terminal ( 5 respectively. 6 ) is releasably connected. Thermal switching device according to at least one of the preceding claims, characterized in that the contact extension ( 8th . 9 ) is designed as a leaf spring. Thermal switching device according to at least one of claims 1 to 4, characterized in that the contact extension ( 8th . 9 ) on the free end of the connection ( 5 respectively. 6 ) can be plugged. Thermal switching device according to claim 8, characterized in that the contact extension ( 8th . 9 ) bent-up receiving channels ( 21 ) having. Thermal switching device according to at least one of claims 1 to 9, characterized in that the contact extension ( 8th . 9 ) has an open C-like shape or closed shape along its vertical extent. Thermal switching device according to at least one of claims 1 to 4, characterized in that the contact extension ( 8th . 9 ) loosely rests on both the upper and lower sides and by means of a housing part ( 22 ) is preferably fixed in position without additional mounting step. Thermal switching device according to at least one of the preceding claims, characterized in that the contact extension at its opposite end portion of the terminal a bulge ( 13 ) having. Thermal switching device according to at least one of claims 1 to 6 and 8 to 12, characterized in that the contact extension ( 8th . 9 ) is designed as a spring contact pin. Contact element for a thermal switching device, in particular temperature controller, temperature limiter, temperature monitor or temperature fuse, for connection to a heating device ( 14 ) of an article of daily use, wherein the thermal switching device with the heating device ( 14 ) is in a thermal contact, characterized in that the contact element as a resilient contact extension ( 8th . 9 ) for the connection ( 5 . 6 ) of the thermal switching device is formed. Contact element according to claim 14, characterized in that the resilient contact extension is formed as a leaf spring. Contact element according to claim 14 or 15, characterized in that the contact extension ( 8th . 9 ) at least one preferably planar trained mounting area for attachment of the contact extension ( 8th . 9 ) has at the connection of the thermal switching device. Contact element according to claim 16, characterized in that the mounting region is equipped with a plug-in receptacle. Contact element according to claim 19, characterized in that in the mounting area bent receiving channels ( 21 ) are provided. Contact element according to claim 13 to 18, characterized in that the contact extension ( 8th . 9 ) has a contact region for contacting the thick film heater. Contact element according to claim 19, characterized in that the contact region of the contact extension ( 8th . 9 ) a bulge ( 13 . 14 ) having. Contact element according to claim 14 to 20, characterized in that the contact extension ( 8th . 9 ) has an open shape in that one end portion of the contact extension forms the mounting portion and the other end portion forms the contact portion. Contact element according to claim 14 to 20, characterized in that the contact extension ( 8th . 9 ) has a closed shape in that the two open end portions of the contact extension form the contact area. Contact element according to claim 14 to 22, characterized in that the contact extension ( 8th . 9 ) has at least one preferably a plurality of holding projections. Contact element according to claim 23, characterized in that as a holding projection provided on the leaf spring between the angled areas, angularly oriented to leaf spring retaining wing ( 23 . 24 ) is provided. Contact element according to claim 14, characterized in that the resilient contact extension is designed as a spring contact pin.

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