FI72688C - TRACTOR DRAGKROK. - Google Patents

Description

1 72688

Tractor towbar - Traktorns dragkrok

The invention relates to a tractor towbar according to the preamble of claim 1.

FI patent publication 45637 discloses a telescopic towbar for a tractor. This towbar consists of a boom device 5 comprising a rigid guide rail and a slide piece arranged to move back and forth on it. The guide rail and slide piece are located below the tractor body. A double-acting piston-cylinder device is arranged between the guide rail and the slide piece, which is driven by the tractor's own hydraulics. Either the 0 guide rail or the slide piece is arranged on the pivot shaft to be supported on the tractor frame. The towbar can be turned with the tractor's lifting device, which is connected to the towbar with separate bars. The piston-cylinder device is controlled by a valve located in the tractor cab. When lifting and lowering a towbar according to FI patent 45637, two movements have to be controlled and adjusted simultaneously, i.e. the vertical movement of the lifting arms and the associated rods and the piston-cylinder blade device. This is particularly disadvantageous when it is desired to disconnect the tractor from the coupling to the trailer so that the distance between the tractor and the trailer is not changed. However, the solution according to FI patent publication 45637 provides a limited operating range in the longitudinal vertical plane of the tractor.

FI patents 54776 and 58741 disclose towing hook solutions in which, in addition to vertical movement, the hook performs a longitudinal, forced steering movement of the tractor during coupling and uncoupling of the trailer. Said hook structures, as well as the solution according to FI patent publication 45637, provide the advantage that the driver can see the hook well in the coupling position.

The object of the present invention is to combine a known, practically proven longitudinal movement of a tractor with a longitudinal movement 2 72688 with a solution which can simply implement a limited operating range of the towing hook in the longitudinal vertical plane of the tractor.

To achieve this object, the tractor-5 towbar according to the invention is mainly characterized by what is set forth in the characterizing part of claim 1. In this towbar solution, the vertical movement of the tractor's lifting arms is the only steering movement. The limited operating range is provided by the articulation mechanism according to claim 1 together with the horizontal forces acting between the tractor 10 and the trailer or the like. In this case, the advantage of a simple steering movement is that, especially during the uncoupling of the tractor and the trailer or the like, the distance between the tractor and the trailer or the like does not have to be changed, but the towbar structure 1.5 selects a suitable uncoupling path. In many practical situations, where uncoupling takes place, for example, on a sloping or soft surface and the trailer's load compartment is full, this operation is very advantageous, since the tractor and trailer do not have to be moved relative to each other and the uncoupling control is not complicated. The fact that the towbar can in principle operate in a certain vertical and longitudinal operating range of the tractor thus has the advantage that the towbar functions always take place using the most favorable trajectory. When uncoupling the trailer from the tractor, the towing hook lowers almost vertically. Correspondingly, in the coupling situation, the towbar is in the lowered position in its rearmost position, whereby the visibility of the towbar from the tractor cab is good. The limited rotation between the second articulated arm and the towbar body allows the hook in its upper-50 position to always be in the locking position. Namely, at the end of the coupling position, the movement of the second articulated arm and the drawbar body with respect to each other, limited by the stop, allows a sufficient force to be transmitted in the longitudinal direction of the hook body to move it to the locking position. In addition, the> 5 tractor towing hook according to the invention has the advantage that if the trailer and / or the tractor inadvertently or intentionally

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3 72688 move relative to each other during coupling or uncoupling, the hook is able to compensate for such movements within a limited operating range. This avoids the large stresses that may occur on the towbar in such situations.

The invention is further illustrated in the following description with reference to the accompanying schematic drawings, in which Figures 1-3 show different extreme positions of the hook and Figure 4 schematically shows the operating area seen from the side.

Figure 1 shows a schematic side view of a towbar according to the invention in the locking position, while Figure 2 shows it in the initial phase of coupling and Figure 3 in the disengagement phase.

.5 The towbar according to the invention is attached to the rear of the tractor body 1. The hook 2 is attached to the towbar body 3, which in the locking position is in a horizontal position below the rear of the tractor body 1. The towbar body 3 is located in the guide 4, which is articulated to the tractor body 1 by a joint.5. The body 3 of the towbar is able to move in the guide 4 in its longitudinal direction mainly in the longitudinal direction of the tractor when the guide 4 rotates in a vertical plane, when other forces acting on the towbar allow the body to move relative to the guide.

The towbar comprises a first articulated arm 6 and a second articulated arm 7. The first articulated arm 6 is articulated in a vertical plane for rotation about its attachment point 8 located in the tractor frame. According to Fig. 1, in the locking position, the first articulated arm is in an almost vertical position, so that the attachment point 8 of the tractor body and the first articulated arm 6 is lower than the articulation point 9 between the first articulated arm 6 and the second articulated arm 7. The second articulated arm 7 is _____ - TT- 4 72688 9, in turn, is articulated to the towbar body 3 by a joint 10. As shown in Figure 1, the second articulated arm 7 is also in a nearly vertical position in the locking position. A stop 11 is arranged in the towbar body 3, which prevents relative rotation of the towbar body 5 and the second articulated arm after the stopper 11 corresponds to the second articulated arm 7. Thus, especially in the coupling situation, a rigid connection is formed between the towbar body 3 and the second articulated arm 7. The angle between the body 3 of the towbar and the second articulated arm 7, where the stop 11 corresponds to the second articulated arm 7, can be e.g. about 90 °. Coupling and uncoupling of the towbar can advantageously be effected by means of the lifting arms of the tractor, which act on either the first articulated arm 6 or the second articulated arm 7.

Figure 2 shows the towbar at the beginning of the coupling situation. In this case, by acting on the drawbar of the tractor's lifting arms, the towing hook performs the trajectory shown by the broken line 12 in the locking position.

The trajectory 12 is almost vertical at the beginning and at the end of the trajectory the towbar 2 moves forward in the longitudinal direction 20 of the tractor. The second articulated arm 7 corresponds to the limiter 11 in the coupling situation, whereby there is a rigid joint between the second articulated arm 7 and the towbar body 3 in the lifting situation. The towbar body 3, in turn, has moved backwards in the guide 4 the distance (dimension L) allowed by the stop 11.

Figure 3, on the other hand, shows a detachment step in which forces, in particular horizontal forces, are applied to the towbar from the tractor body and the trailer or the like connected to the towbar, which can be used to detach the towbar using the vertical or nearly vertical path 13 shown in broken lines. In this case, the second articulated arm 7 is detached from the stop and the towbar body in the guide 4 rotates vertically in its forward position or almost in the forward position in the vertical plane.

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Figure 4 is a schematic side view of the operating range of the towbar 14. Depending on the forces acting on the towbar, different trajectories can be created in the operating range during uncoupling and coupling. The front movement path 15 of the operating area 14 is a situation in which the hook performs a circular arc-shaped movement determined by the length of the towbar body around its articulation point 5 (dimension R). However, if, for example, during uncoupling the distance between the tractor and the trailer connected to it by means of the towing hook is not changed, the towbar body 3 If the trailer and / or the tractor inadvertently or intentionally move relative to each other during coupling or uncoupling 15, the hook is able to compensate for such movements within the operating range 14 by moving, for example, to trajectory 16 from trajectory 13, whereby the towbar body 3 moves in guide 4. possibly in situations like this 20 large burdens arise.

The longitudinal movement of the towbar body can also be realized differently from that shown in the figures, e.g. so that the body end 3 is located mainly in the longitudinal guide of the tractor body. In a manner known per se, the body of the towbar can be bifurcated, in which case there are likewise possibly two guides 4 or the like and the towbar 2 is fastened to a transverse beam connecting the run-up arms. In this case, of course, it is also possible to place two articulated arms 6 and 7 on the hook in pairs for each lifting arm.

Claims (1)

A tractor towbar for releasably attaching a trailer or the like to a tractor, the towbar being operated by means of tractor lifting arms, the towbar comprising a vertically rotating hook body (3) below the tractor body (1) having a limited, mainly longitudinal length of the tractor the possibility of movement in a guide (4) attached to the tractor body when the forces acting between the tractor and the trailer or the like enable this and the articulation mechanism with the first articulated arm (6) between the tractor lifting arms, the tractor body (1) and the hook body (3), articulated in a vertical plane for rotation about its attachment point (8) in the tractor body (1), characterized in that the articulation mechanism comprises a second articulated arm (7) articulated to provide a limited operating range (14) known per se in the longitudinal vertical plane of the tractor. (9) the first articulated arm (6 ) and the towbar body (3) for rotation in a vertical plane and the rotation of which with respect to the towbar body (3) is limited by a stop (11) for guiding the towbar to the 0 locked position. Towbar according to claim 1, characterized in that the stop (11) is arranged between the second articulated arm (7) and the towbar body, preferably on the towbar body (3) and in that the second articulated arm (7) corresponds to the stop (11) on the towbar body (11). 3) and the angle between the second articulated arm (7) is approx. 90 °.