IE49030B1 - Hook for coupling trailer - Google Patents

Abstract

This device comprising a support fixed to the tractor and a hook like tying piece is characterized in that said support is a vertical plate and that said hook-like piece is integral of a carriage, slider or slide which can move reciprocatingly in a vertical rectilinear translation with respect to said vertical plate. This device allows the tying of tractor-drawn vehicles and farming tools.

Description

The invention relates to a new type of coupling device fixed to the rear part of a tractor vehicle for the purpose of coupling the shaft of a single-axle or two-axle trailer, of an agricultural machine or civil engineering machine, or of a borne implement, this device being of the type in which the hook member is displaced along a vertical trajectory so as to pass from the position of engagement of the shackle of said shaft to the coupling position (such as that which is described in Patent Publication DE-B-1059297, DE-B-1065281 or GB-A-875270).

The invention not only aims to provide a universal device enabling the automatic coupling of the coupling to be achieved either directly or through the medium of an oscillating bar of known type, but also, and principally, the invention completes coupling devices of the type in question by means of a safety member entering into action automatically and preventing all accidental uncoupling.

In general, the particular regulations of different countries impose locking measure precautions for elements cooperating in their coupling position.

In order to obtain locking in the upper position DE-B-1059297 proposes a semi-cylindrical bolt turning about a horizontal axis in a circular catch adapted for cooperation with a slot of the same shape provided 25 horizontally on the vertical tenon penetrating the catch in the coupling position. The turning bolt is held in the locking position by means of a spring and is disengaged by the action of a steering gear (cable).

Thus the operator can synchronise two manoeuvres, that of raising the shaft pick-up member and that of opening the catch. - 3 It is obvious that this synchronism is uncertain, in particular, by virtue of the fact that the coupling device is out of the view of the operator.

GB-A-875270 also describes a coupling of the type in question including on the one hand a slide integral with the tractor and carrying a vertical locking tenon and on the other hand a carriage vertically displaceable with respect to said slide by means of a jack, the carriage of which is integral with the catch before cooperation with the tenon.

The locking of the slide and carriage in the coupling position is obtained by a lever including a pin articulated on the slide and thrust towards a carriage slot by a compression spring; unlocking being achieved by a reversing bell-cranking lever.

Accordingly, locking is only achieved therefore if the pin is appropriately engaged in the slot, which supposes a precise and non-opposed descent of the carriage in the slide.

In other respects, such a locking is less reliable, the spring being capable of being decompressed for example by a jolt or shock received by one of the vehicles and more particularly by the trailer.

The security device according to the present invention is devised in such a way that renders its entry into action automatic, without the necessity of any precision in the coupling manoeuvre. - 4 Accordingly, the invention provides a coupling device enabling the automatic coupling of the shackle terminating the shaft of a trailer to a towing vehicle said device conprising a hook elenent integral with a movable element which is alternately displaced in vertical translation in directions which are rectilinear with respect to a fixed portion supported by the towing vehicle from a low position in which the shackle is engaged, to a high coupling position for the purposes of which a counter-element closes the shackle in said hook element, inadvertent lowering of the hook element being prevented by a bolt comprising a hook pivoting in a vertical plane about a horizontal axis supported by the said fixed portion and engaging in the locking position with a member supported by the vertically movable element, said member being a horizontal catch engaging in the high position with the hook whose internal curved profile ensures locking and whose external profile in the form of a cam causes the automatic retraction of the hook from contact with the vertically rising catch at the moment preceding coupling.

Other features and advantages will emerge in the course of the description and claims given below, which, in conjunction with the accompanying drawings given as an example of embodiment, will make it understood how the present invention can be put into practice. - 5 Figure 1 is a diagram showing the device forming the object of the invention in the bottom engagement position.

Figure 2 is a profile view in section of this device.

Figures 3 and 4 show two alternatives for the operation of the safety bolt preventing accidental uncoupling.

As can be seen in Figures 1 and 2, the device in question comprises a plate 1 fixed to the rear part 2 of the tractor, and a carriage or slide 3 ending at its bottom end in a hooked part, which is here in the form of a base 4 carrying a vertical stud 5 intended to be inserted into the ring or shackle 6 of the shaft 7 of the towed vehicle.

The carriage or slide 3 can make vertical movements of rectilinear translation relative to the plate 1 through the action of the conventional lifting arms provided on most tractors (and not shown in the drawing), or better still with the aid of hydraulic or pneumatic jacks such as 8b (Figure 2), disposed laterally.

Because of this translation, the stud 5 is displaced (Figure 2) from the bottom position A of engagement of the shackle 6 to a top towing position B.

As can be seen in Figure 1, in these two end positions the stud 5 remains visible to the driver, even - 6 if the latter is provided with a cab, because in that case a bottom window is always provided which enables him to see the ground in the zone immediately adjacent to the wheels .

In a preferred embodiment the plate 1 fixed to the tractor forms a kind of slide guide in which a movable part (carriage, cursor, or slide) 3 can slide vertically.

This plate 1 is substantially U-shaped and composed of a plate la rigidly fixed to the vehicle and secured to two lateral side-pieces lb, angles lc being welded to the plate la in some cases and to the sidepieces lb in the other cases, so as to form a slide guide on each side of the plate 1.

The carriage, cursor, or slide 3 is formed of two vertical lateral flat bars connected together by the horizontal base 4 supporting the coupling stud 5. Each flat bar slides in one of the slide guides previously defined.

Various modifications of this arrangement can 2o obviously be conceived. For example, the carriage could be provided with rollers rolling inside each slide guide.

Also as an example, the hook-shaped part could be formed by replacing the assembly 4/5 by a conventional hook, but this solution would be less satisfactory because the device forming the object of the invention - 7 would be deprived of some of its capability of universal use, since it could no longer be fitted with an oscillating bar of conventional type.

In the solution which has just been described 5 with reference to Figure 2, the base 4 carries in fact on its bottom face on the one hand a pin 8 at its front end and on the other hand a runner 9 at its rear end.

This runner 9 is formed between a sector 10, fastened laterally to the base 4, and the said base.

The oscillating bar 0 shown in chain-dotted lines in Figure 2. is introduced into the runner 9 and rests on sector 10, to which it may be joined in conventional manner by a pin, while its judiciously shaped eye 0a receives the pin 8 passing through it and is supported by the head 8a of the pin 8.

Near the base 4 the carriage 3 is provided on each side with an operating shaft 11 on which is fitted either the end of the conventional lifting arms or the end of the rod 8c of the piston of a jack 8b whose cylinder is fastened to the side-pieces lb of the fixed plate 1.

In principle, only raising is effected by means of the lifting arm or jack, the carriage being lowered by gravity.

Safety rules require that the hook-shaped part should be locked positively during the towing period. - 8 According to the invention in order to conform to this rule, the carriage 3, or more precisely its base 4, is provided with at least one lateral pin 12 intended to cooperate with a hook 13 oscillating on a shaft 14 journalled in the side-pieces lb.

This hook 13 is held in the position in which it engages the pin 12, for example, by means of a spring 15 acting on a lever 16 fastened to the shaft 14 or to the hook 13.

This hook 13 can be retracted by swivelling on the shaft 14 at the moment preceding engagement of the hook, when the pin 12 rising with the carriage 3 and the base 4 encounters the outer profile of the said hook, which forms a cam.

This retraction can also be effected when it is desired that the carriage should redescend by gravity, either in order to release the shackle 6 or to permit the coupling of another trailer shaft.

Figure 3 illustrates an embodiment in which the 2o hook 13 is fastened to one end of a lever 17, the other end of which can be operated by a control, for example a Bowden cable 18.

It will readily be understood that traction applied to this cable will rock the lever 17 about the shaft 14 and consequently swivel the hook 13, thus enabling it to free the pin 12. - 9 In the embodiment shown in Figure 4, the core of an electromagnet 19 is articulated to the end of a lever 20 secured to the shaft 14 or to the hook 13.

The energisation of the coil of this electromagnet brings about the rocking of this lever 20 and consequently the swivelling of the hook in the retraction direction, thus freeing the pin 12. A spring counteracts this electromagnet in order to return the hook to the locking position.

Without it being necessary to give a fuller description or to provide an additional Figure, it can readily be understood that the electromagnet could be replaced by a pneumatic or hydraulic jack.

The apparatus is advantageously provided with a locking device of the kind described for each of its sides, thus forming a double safety device preventing accidental uncoupling.

Moreover, since the hooks 13 are oh the outside of the arrangement, they constitute the visible refer20 ence indicator required by certain regulations, permitting verification of the operative position of the hooks.

The invention is more particularly applicable to agricultural or civil engineering tractors.

Claims (4)

1. A coupling device enabling the automatic coupling of the shackle terminating the shaft of a trailer to a towing vehicle, said device conprising a hook element integral with 5 a movable element which is alternately displaced in vertical translation, in directions which are rectilinear with respect to a fixed portion supported by the towing vehicle from a low position in which the shackle is engaged, to a high coupling position for the purposes 10 of which a counter-element closes the shackle in the said hook element, inadvertent lowering of the hook element being prevented by a bolt comprising a hook pivoting in a vertical plane about a horizontal axis supported by the said fixed portion and engaging in the locking 15 position with a member supported by the vertically movable element, said member being a horizontal catch engaging in the high position with the hook whose internal curved profile ensures locking and whose external profile in the form of a cam causes the automatic 20 retraction of the hook from contact with the vertically rising catch at the moment preceding coupling.

2. A coupling device as claimed in claim 1, in which the hook element is constituted by a vertical stud supported by a base integral with the vertically 25 moving element, said base supporting the horizontal locking catch on its upper face.

3. A coupling device as claimed in claim 2, comprising means for the instantaneous fastening of a vehicle shaft, the fastening means being constituted, on one hand, by 30 a vertical pin disposed below the base at its front end and, on the other hand, at its rear end by a slide formed between a perforated sector integral laterally with the base, and the said base.

4. -9030 - 11 4. A coupling device according to claim 1, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.