FI67514C - LUNNGRIPARE - Google Patents

Description

6751 4

Juontokoura

Lunngripare

The invention relates to a skidder for attachment to a 3-point lifting device for a tractor, such as an agricultural tractor, the skidder comprising a frame structure, scissor members and a hydraulic actuator adapted to move the scissor members to the open position and the tractor to the closed position, respectively. the body portion of the side frame structure is adapted to pivotally pass through the drawbeam.

The currently known plotters operate as follows. The agricultural-10 tractor is used to drive the felled trees close enough so that the felled trees can be lifted and transported to the desired location with the help of a loader, eg to a felling site. If necessary, stacking is carried out at the county seat using a grapple. When working in the field, the grapple grabs a bundle of wood on either side of the agricultural tractor and when the load is straight in 15 countries, the grapple frame is locked so that the grapple cannot turn sideways. The load is then lifted into the air with a grapple and driven off-road. The disadvantage of the known grapple is that often quite heavy loads when driving in difficult terrain conditions tend to swing and cause stresses to the agricultural tractor. Correspondingly, the agricultural tractor also tends to oscillate in difficult terrain conditions, and this oscillation results in stresses on the grapple and often part of the timber bundle can become detached from the grip of the grapple.

With regard to the state of the art, reference is made to FI patent No. 50670. This known traction and gripping device for 25 tree trunks comprises a front frame part which can be attached to a tractor or other basic machine and a second frame part articulated to the front frame part and to which are articulated transverse, underlying and clamp-like gripping arms for gripping the traceable trees 30. The front body is a rigid assembly. The front body portion and the second body portion are, in combination, rigid in a substantially vertical plane 2,67514. The front body part is connected with its mounting fork or the like below the rear axle line of the basic machine, preferably also to the front side. The front frame part is connected to the basic machine by power devices only for weight transfer and / or gripping the load.

5

It is an object of the invention to provide an improvement over the currently known plot-to-grapples. It is a more detailed object of the invention to provide a skewer which avoids the above-mentioned disadvantages.

The objects of the invention are achieved by a skein, characterized in that the lateral oscillation of the load in the grapple formed by the scissor members with respect to the pivot axis is adapted to cause the push arm attachment point to pivot laterally, causing the push arm to cause the load

According to claim 2, the pivoting axis of the grapple is known per se to be arranged obliquely obliquely, the pivoting axis being adapted to cause a self-centering torque on the plow.

20

The invention will be explained in detail with reference to a preferred embodiment of the invention shown in the figures of the accompanying drawing, to which, however, the invention is not intended to be exclusively limited.

Figure 1 shows an axonometric view of a preferred embodiment of a plotter according to the invention.

Fig. 2 shows the plotter of Fig. 1 in a side view.

In the embodiment according to Figures 1 and 2, the trowel according to the invention is generally indicated by reference numeral 10. The trowel comprises a frame structure 11,11a, scissor members 12 and 13 and a hydraulic cylinder 14 adapted to move the scissor members 12,13 to the open position and the closed position, respectively. . In this embodiment, the body portion 11a on the side of the tractor-35 not shown is adapted to rotatably pass through the drawbeam 15, and the body portion 11a acts as a pivot shaft 20 of the skid 10. The skeleton structure 11,11a of the plow 10 can be locked by the drawbar 15 locking device 16. , whereby the skein 10 cannot turn around the pivot axis 20.

The plow 10 according to the invention is, as is known per se, fastened to the tractor's 3-point lifting devices, the push arm 17 being fitted to the fastening point 17a and the drawbars 18 to the fastening points 18a, respectively. According to Fig. 1, in this embodiment, the attachment point 17a of the push rod 17 is formed by a pin attachment. Reference numeral 19 in Fig. 2 denotes the timber load to be lifted by the loader 10.

The operation of the plotter 10 according to the invention is as follows. When the load 19 is in the grapple formed by the scissor members 12,13 of the skid 10, the load 19 causes a moment on the attachment points 18a of the drawbars 18, because the frame structure 11,11a of the skid 10 is pivotally fixed, i.e. the locking device 16 does not form a lock. The load 19 is kept in balance by a push arm 17 with a tensile stress due to the load 19. When, for example, an agricultural tractor drives a load completely in the air with a load 19, the load 19 can oscillate laterally with respect to the pivot axis 20 20. Due to this, at the same time, the attachment point 17a of the push arm 17 in the skid 10 also turns to the side, whereby the push arm 17 forces the load 19 to rise slightly. Since, in accordance with the laws of nature, the aim is always to reach the minimum energy, this effect of the push rod 17 becomes the moment of restoring or concentrating the load 19.

25

According to a preferred embodiment of the invention, the pivot shaft 20 is arranged obliquely backwards, whereby such a pivot shaft 20 automatically causes a centering torque.

When the tractor is driven on public roads with a load 19, the skid 10 is locked to the drawbeam 15 by a locking device 16 so that, for safety reasons, the skid 10 cannot swing laterally with respect to the pivot axis 20. In the solution according to the invention, it is generally sufficient that the rotation of the drawbeam 15 is limited to a certain limit value 35, such as e.g. + 30 °.

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4,67514

Only one preferred embodiment of the invention has been described above, and it will be clear to a person skilled in the art that numerous modifications can be made to it within the scope of the inventive idea set out in the appended claims.

Claims (2)

6751 4 Pa ten 11 ivaa t atus A grapple for attachment to a 3-point linkage (17,18) of a tractor, such as an agricultural tractor, the stack (10) comprising a frame structure (11,11a), scissor members (12,13) and a hydraulic actuator (14) adapted to move the scissor members 5 (12,13) to the open position and to the closed position, respectively, and in which the frame part (11a) of the tractor-side frame structure (11, 11a) is adapted to pivot in an accessible manner to go to the drawbar ( 15), characterized in that the lateral oscillation of the load (19) in the grapple formed by the sex members (12, 13) with respect to the pivot axis (20) is adapted to cause the attachment point (17a) of the push arm (17) to turn laterally, the push arm (17) cause the load (19) to rise slightly upwards, resulting in a torque restoring and centering the load (19). A grapple according to claim 1, characterized in that the pivot shaft (20) is, as is known per se, arranged backwards obliquely, the pivot shaft (20) being adapted to cause a self-centering torque on the plotter (10).