WO2002066360A1

WO2002066360A1 - Loader

Info

Publication number: WO2002066360A1
Application number: PCT/FI2002/000142
Authority: WO
Inventors: Risto Heikkilä
Original assignee: Heikkilae Risto
Priority date: 2001-02-22
Filing date: 2002-02-21
Publication date: 2002-08-29
Also published as: WO2002066360A8; FI20010346A0

Abstract

The present invention relates to a loader to be primarily used in logging machines. The loader comprises a turntable (2) for connecting the loader to a base machine (1) and arms consisting of a primary arm (3) and a transfer arm (4) that are interconnected in an articulated manner. A lifting cylinder (5) and a transferring cylinder (6) that are attached by means of a connecting plate (9) to the arms are arranged to control the arms. The transferring cylinder is thus attached directly to the connecting plate in connection with the primary arm and the control movement of the lifting cylinder is in turn transmitted thereto trough a stabilizer bar (10) and a lower link plate (11). The lifting cylinder and the transferring cylinder controlling the arms are thus arranged one on top of the other, on the same shear plane, so that the loader has narrow and low structure.

Description

LOADER

FIELD OF THE INVENTION

[0001] The present invention relates to a loader in accordance with the preamble of claim 1. [0002] This loader is primarily employed as a loader in logging machines. Various timber handling apparatuses, such as a cutting head, i.e. a harvester part, or a feller head, an energy wood grapple or a timber handling grapple, are generally mounted on one end of the loader. Thanks to its reach and movement path, this loader enables treating and felling of trees, either in a selective manner, in which case a forest is thinned, or as a final felling, in which case a forest is harvested on a clearfell basis. In general, the loaders are mounted on a base provided by a logging machine by means of a so-called turntable platform.

BACKGROUND OF THE INVENTION [0003] It is previously known to use in logging machines a timber loader that comprises separate lift and secondary arms, each with specific movement paths and hydraulic cylinders that control them, so that the hydraulic cylinders and the arms have no common movement paths. Thus, the movement paths of the lift arm and the secondary arm are not interconnected. When the arms of the loader are used, it is necessary to make two separate motions simultaneously in order to provide a horizontal motion with the end of the secondary arm within the range of the arm.

[0004] The individually actuated arms of the known loaders make the movement path consist of jerky, reciprocated up and down motions, when the loader head is controlled to a horizontal motion, and not direct and smooth motion which would be advantageous for a load or an actuator. Uneven movement path of this kind increases energy consumption of the loader, and stresses acting on the arms become disadvantageously high.

[0005] In apparatuses, in which the actuating cylinder of the lift arm is located below the lift arm, the cylinder is often at risk, because it is exposed to impacts from tree trunks to be handled with the loader. In addition, when the loader is in the vertical position, it often occurs that the end of the secondary arm, or the device mounted on the end thereof, hits the unprotected lifting cylinder. [0006] On one hand, so-called movement path loaders are also known, in which the motions of the arms are interconnected so as to achieve easier controllability. However, in these solutions the placing of actuating cylinders, in particular of the lifting cylinder, has posed problems. Thus, in the known solutions the arms must have been placed on the turntable platform by means of a relatively high pillar-like arrangement, and consequently the mass centre of the loader, and therewith that of the whole machine, becomes very disadvantageous and makes the smooth use of the loader difficult.

[0007] On the other hand, if the pillar-like arrangements are avoided, the lifting cylinder is arranged in a position intersecting with the primary arm, either beside it or penetrating the arm. However, the structure either weakens the structure of the primary arm or requires the turntable platform to have a larger slewing ring than conventionally for connecting the loader thereto. The solution is not satisfactory either, because it makes it difficult to guide the necessary pressure media pipes, or the like, from the base machine to the loader.

[0008] The previous solutions have thus involved several problems. So, it has been difficult to guide the arms, because it has been necessary to control two, even three, separate, independent motions. Also, the placing of the actuating cylinders has subjected them to damage during use. Moreover, the placing of the actuating cylinders has caused problems to the stability of the working machine and to other installation work necessary for the machine.

BRIEF DESCRIPTION OF THE INVENTION

[0009] The object of the present invention is to provide a solution, by which the drawbacks of the prior art could be mainly avoided, and a novel, durable, simple and reliable loader would be achieved.

[0010] This is achieved with a loader having the characteristics defined in the claims of the present invention. More precisely, the device of the invention is mainly characterized by what is set forth in the characterizing part of claim 1.

[0011] The preferred embodiments of the invention are disclosed in the dependent claims.

[0012] Considerable advantages are achieved by means of the invention. The loader of the invention comprises actuators, i.e. a lifting cylinder and a transferring cylinder, that control the arms and are arranged superim- posed in connection with the primary arm of the arms, advantageously in the same shear plane. At the same time, this actuator placement allows them to be designed as advantageous in size as possible.

[0013] The placement of the lifting cylinder in accordance with the invention further makes the loader structure low and narrow, and the mass centre of the working machine is located very low. The advantageous location of the mass centre, in turn, enables use of a less costly slewing ring having more advantageous structure for securing the loader to the base machine. Because of the low structure, the visual field of the machine operator is also more open than in the prior art apparatuses.

[0014] In the present loader, both of the actuators are also located close to the base machine, where they are protected as the logging machine moves in the terrain. As the actuators are behind the primary arm during use, in view of the load to be handled therewith, the actuators are also well pro- tected against the secondary arm or impacts from devices and their loads arranged therein.

[0015] The movement path of the loader according to the invention is ideal, because the horizontal transfer movement throughout its range is performed using only one cylinder, i.e. the transferring cylinder, whereby the loader moves very smoothly. The angles of the primary arm and the secondary arm with respect to the vertical plane remain substantially the same throughout the range of the arms, and consequently the mass centre of the loader is always optimally as close to the attachment point and the base machine as possible.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following, preferred embodiments of the invention will be examined with reference to the attached drawing, wherein

Figure 1 is a schematic side view of a first preferred embodiment of a loader according to the invention; Figure 2 shows a detail of the loader in Figure 1 , protrusion of a lifting cylinder piston being at its lowest;

Figure 3 shows a detail of the loader in Figure 1 , protrusion of a lifting cylinder piston being at its highest;

Figure 4 is a schematic side view of a second preferred embodiment of the loader according to the invention; and Figure 5 is a schematic side view of a third preferred embodiment of the loader according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE LOADER [0017] In the following, some preferred embodiments of the present loader are described with reference to the above-mentioned figures. Thus the loader comprises structural parts indicated in the figures by reference numerals, which correspond to those used in this specification.

[0018] The loader of Figures 1 to 3 thus comprises a tilting turntable 2 arranged in a logging machine frame, i.e. a base machine 1 , by means of a turntable platform known per se, for instance. Loader arms comprising a primary arm 3 and a secondary arm 4, interlinked in an articulated manner, are arranged in the turntable, the primary arm being rotatably attached to the turntable at the base end. The distance between the attachment point of the pri- mary arm of the loader and the base machine 1 is small, whereby the total structure of the loader is low and the mass centre of the device is close to the base machine.

[0019] Two advantageously pressure-medium-operated actuators, i.e. a lifting cylinder 5 and a transferring cylinder 6, are arranged to control the movements of the arms in the loader. In the embodiment of the figures, the transferring cylinder is substantially parallel to the primary arm and arranged at a first end, i.e. cylinder end, substantially to the base end of the primary arm 3 on the side of the turntable 2. Advantageously, the transferring cylinder is then rotatably attached to the primary arm, by means of a mounting piece 7. This mounting piece 7 is arranged to link the primary arm with the turntable through a mounting plate 8. However, both the transferring cylinder and the primary arm can be attached, each separately, with common or separate mounting plates to the turntable. The lifting cylinder is also advantageously attached at its first end, i.e. cylinder end, to the same mounting plates in the turntable, but the turntable may also have specific securing means for the lifting cylinder. However, the lifting cylinder is arranged at an angle with the primary arm, the angle being 45 ° to 135 °, preferably about 90 °. The lifting cylinder thus projects outwardly in a direction above the securing point of the primary arm in the normal use of the loader. [0020] The control movements produced by the actuators are arranged such that they are transmitted to the arms through a connecting plate 9 in the loader. This connecting plate is arranged to receive control movements produced by a piston of the transferring cylinder 6, opposite the turntable. At the same time, the same connecting plate is arranged to receive the control movements produced by the lifting cylinder 5 and the piston thereof, the lifting cylinder being almost at a right angle to the transferring cylinder. The movements of the lifting cylinder piston are thus transmitted to the connecting plate through a stabilizer bar 10 that communicates with the connecting plate. The substantially rigid stabilizer bar is arranged at a first end to the connecting plate and at a second end to an elongated lower link plate 11 controlled by the lifting cylinder. Thus the other end of the lifting cylinder, opposing the turntable, i.e. the piston end, is rotatably attached to the lower link plate, which in turn is arranged to the turntable through mounting plates 8, for instance. [0021] The stabilizer bar 10 movement and the structure of devices and means controlling the arms will be particularly advantageous if the lower link plate 11 and the primary arm 3 are arranged to have a common link point. This structure provides the loader with a rigid supporting triangle consisting of the stabilizer bar, the lower link plate and the transferring cylinder, whereby troubles in the stabilizer bar or the primary arm movement can be avoided.

[0022] The transfer movement of the piston in the lifting cylinder can be utilized particularly efficiently, when a torque arm is arranged between the connecting points of the lifting cylinder and the stabilizer bar 10 in the lower link plate in accordance with the figures. The loader is then controllable with an advantageous small-sized cylinder. In accordance with the figures, the link point between the lifting cylinder 5 and the lower link plate is in this embodiment further away from the connecting point between the mounting plate 8 and the lower link plate than the link point between the stabilizer bar and the lower link plate. At the same time, the line A connecting the link point between the lifting cylinder and the mounting plate with the link point between the stabilizer bar and the lower link plate, as well as the line B that connects the both ends of the lifting cylinder, i.e. the longitudinal axis of the lifting cylinder, are arranged to intersect. Thus an angle α, which is wider than 0°, advantageously 0° to 20°, is provided between the lines. To provide the angle between the lines ensures that the lifting cylinder has no blind angle as the loader is in the horizontal position but there will always be a sufficient lifting moment for con- trolling the loader. In this embodiment of the loader the lower link plate is curved or polygonal in shape.

[0023] In the embodiment of Figures 1 to 3, the movement path of the loader is controlled with wide-angle links 12 in the connecting area of the primary and secondary arms as shown in Figure 1. These wide-angle links are controlled with an auxiliary arm 13 extending from the connecting plate 9. As the wide-angle links assist in producing the control movement, an auxiliary yoke 14 that is rotatably arranged in the primary arm 3 and in the connecting plate is also arranged to control the movements of the connecting plate. [0024] In a second embodiment according to Figure 4, the loader is arranged to be controllable by means of a transferring cylinder 6 and a stabilizer bar 10 extended to the connecting area of the primary and the secondary arms. The stabilizer bar and the transferring cylinder are arranged to the connecting plate 9, which is rotatably attached to the base portion projecting from the secondary arm 4. Additionally, in this loader embodiment, there is an auxiliary yoke 14 arranged to control the movements of the connecting plate, linking the connecting plate with the primary arm and arranged to be rotatable with respect thereto.

[0025] A third embodiment of the loader is shown in Figure 5. At the simplest, the connecting plate 9 is here attached rigidly to the base of the secondary arm 4, the connecting plate thus receiving and transmitting the control movements of the transferring cylinder 6 and the stabilizer bar 10, directly attached to said connecting plate, to the secondary arm.

[0026] In the present loader the lifting cylinder 5 and the transferring cylinder 6 can be arranged to be substantially on the same shear plane with the primary arm 3, which permits the apparatus to have an advantageous, narrow structure. The lift and transferring cylinders being located close to the base machine 1 in accordance with the figures, they are at the same time well protected when the loader moves. Moreover, as the actuating means are posi- tioned on the opposite side of the secondary arm 4, articulated to the primary arm, they are protected against possible impacts from the secondary arm or an actuator 15 connected thereto.

[0027] When the loader is used, the arms can be straightened or retracted with one control movement. The transferring cylinder 6 is then arranged to control a polygon produced in the loader such that when a transfer force, in the direction of the longitudinal axis of the transferring cylinder, is directed to the polygon with the transferring cylinder, the angles of the polygon are changed, which results in substantially simultaneous and equal, i.e. synchronized, movements of the primary arm 3 and the secondary arm 4. This produces a substantially linear movement path for the outer end of the secondary arm in the working space. For instance, when the length of the lifting cylinder 5 is not changed but the piston of the transferring cylinder is retracted into the cylinder, thus reducing the total length of the cylinder, the primary arm is provided with a rotating movement towards the base machine. This rotating movement is transmitted to the secondary arm, forcing it to rotate an angle β, which equals the rotation angle β of the primary arm. The primary arm and the secondary arm thus rotate in proportion, the loader thus extending outwardly.

[0028] By positioning the lifting cylinder 5 between the base machine and the lower link plate, it is possible to provide the loader with a lower and more controllable movement than conventionally. In accordance with Fig- ures 2 and 3, even the lifting cylinder having a very short stroke can provide the necessary rotation of the primary arm 3, whereby the movement is fast and yet easily controllable. A change in the protrusion of the lifting cylinder piston affects the height value of the outer end of the secondary arm 4 in a manner known per se. Thus, with a movement in the direction of the longitudinal axis the lifting cylinder piston makes the primary arm rotate with respect to its base through the lower link plate 11 and the stabilizer bar 10 attached thereto. So the shift in the outer end of the primary arm, together with the movement of the link bar, lifts or lowers the outer end of the secondary arm. The movement path of the arms and the height of the outer end of the secondary arm from the base, e.g. from the ground, are selected in this manner.

[0029] It should be understood that the above description and the relating figures are only intended to illustrate the embodiments of the present loader. So, the structure of the loader is not restricted to what is described in the above or to the embodiments defined in the claims, but it will be apparent to persons skilled in the art that the invention can be varied and modified in a variety of ways within the scope of the inventive idea disclosed in the accompanying claims.

Claims

1. A loader comprising a turntable (2) for connecting the loader to a base machine (1) and a primary arm (3) and a secondary arm (4) that are interconnected in an articulated manner, the primary arm being arranged in con- nection with the turntable, whereby pressure-medium-operated actuators, a transferring cylinder (6) and a lifting cylinder (5), are arranged to control these arms, the transferring cylinder being arranged from its first end to the end of the primary arm on the side of the turntable, and from its second end to a connecting plate (9) transmitting the control movements together with a stabilizer bar (10) also controlling the arm movements, and the lifting cylinder being arranged from its first end in connection with the turntable and from its second end to a lower link plate (11) transmitting the lifting cylinder movements to the stabilizer bar, characterized in that the lifting cylinder (5), the primary arm (3) and the lower link plate (11) are rotatably arranged in at least one mounting plate (8) in connection with the turntable (2) such that the lower link plate is arranged to transmit the control movements of the lifting cylinder to the stabilizer bar (10).

2. A loader as claimed in claim 1, characterized in that the primary arm (3) and the lower link plate (11) are connected to the same link point in the mounting plate (8).

3. A loader as claimed in claim 1 or 2, characterized in that the link point between the lifting cylinder (5) and the lower link plate (11) is arranged to be further away from the connecting point of the mounting plate (8) and the primary arm (3) than the link point between the stabilizer bar( ιrj and the lower link plate.

4. A loader as claimed in claim 3, characterized in that the longitudinal axis (B) of the lifting cylinder and the line (A) connecting the connecting point of the lifting cylinder and the mounting plate (8) and the connect- ing point of the lower link plate (11) and the stabilizer bar (10) are arranged to intersect, forming an angle α of 0° to 20° between them.

5. A loader as claimed in any one of the preceding claims, characterized in that the connecting plate (9) is arranged rotatably to the secondary arm (4), and the connecting plate is further attached to the primary arm (3) with an auxiliary yoke (14) that is rotatably arranged from both ends to the connecting plate and the primary arm.

6. A loader as claimed in claim 5, characterized in that the connecting plate (9) is arranged in the secondary arm (4) with an auxiliary bar (13) that is rigid with respect to the connecting plate.

7. A loader as claimed in claim 6, characterized in that the auxiliary bar (13) is arranged, at the end opposite the connecting plate (9), to a wide-angle link mechanism (12) in the secondary arm.

8. A loader as claimed in any one of claims 1 to4, character- i z e d in that the connecting plate (9) is arranged rigidly to the secondary arm

(4).