GB2218890A

GB2218890A - Tractor towing hitch

Info

Publication number: GB2218890A
Application number: GB8812770A
Authority: GB
Inventors: David John Cooper
Original assignee: Agricultural Requisites & Mech
Current assignee: Agricultural Requisites & Mech
Priority date: 1988-05-28
Filing date: 1988-05-28
Publication date: 1989-11-29
Anticipated expiration: 2008-05-28
Also published as: GB2218890B; GB8812770D0

Abstract

A tractor towing hitch has a support arm 1 having a towing element 2 including a hook 3. The hook 3 is disposed externally of the arm 1, whilst a root portion 4 of the element 2 extends into the arm 1 and is connected to the piston rod 6 of a hydraulic ram 5. The arm 1 and cylinder 7 of ram 5 are pivotally connected through a horizontal pivot 8 extending transversely of the tractor. The lifting hydraulics of the tractor are connected with bracket 10 for pivoting the arm 1 and ram 5 about the axis of pivot 8. Operation of the ram 5 slides the hook 3 in or out relative to the arm 1. <IMAGE>

Description

HITCHES This invention relates to towing hitches for vehicles, e.g. agricultural tractors, and is more particularly concerned with so-called "pick-up hitches in which the tow arm of a trailer is engaged by a movable draw bar of the hitch and is lifted from an unhitched or rest position on or near the ground by the vehicle hydraulics into a position for towing.

Various types of pick-up hitch have been previously proposed, see for example EP-A-0138519, US Patent 3863955, GB-A-2042316, US 3450220, US 3421779, US 2725243, SE-312730 and FR-A-2573360. However, such pick-up hitches have a relatively large number of points of articulation and so are susceptible to wear and tear. Some of these previously proposed pick-up hitches are designed with the intention of moving the hook or other towing element rearwardly and downwardly into an unhitched or rest position; in practice it is found that the towing element does not move rearwardly of the tractor by a sufficient distance to ensure that all sizes of driver can retain vision.Additionally, in certain of the previously proposed pick-up hitches, the hook or other towing element is not presented in a favourable juxta position to the tow arm of the trailer if the size, pressure or degree of wear of the tractor tyre is varied. Futhermore, with some of the previously proposed systems, it is not possible to dig the hook or other towing element into the ground if the tow arm of the trailer has sunk into the ground.

Additionally, the hook or towing eye can sway away from obstructions.

It is an object of the present invention to obviate or mitigate the above mentioned disadvantages.

According to the present invention, there is provided a towing hitch having a towing element (eg a hook or towing eye) which is mounted on a support through the intermediary of a piston and cylinder device, the support being adapted to be pivotally mounted on a tractor or other towing vehicle for pivotal movement in an upright plane, the arrangement being such that the distance between the towing element and the pivotal attachment of the support to the tractor can be varied by operation of the piston and cylinder device.

The support is preferably provided with a formation thereon disposed in spaced relationship from the axis of the pivot, said formation being attachable to means for pivoting the support about said pivot. Said means preferably takes the form of existing hydraulics on the towing vehicle.

The support preferably takes the form of an arm from a pivot-remote end of which the towing element extends.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing which is a schematic side view of a pick-up hitch according to the present invention.

Referring to the drawing, the pick-up hitch comprises a support arm 1 having a towing element 2 extending from one end thereof. The towing element 2 includes a hook 3 disposed externally of the support arm 1 and a root portion 4 which extends into the support arm 1. The towing element 2 is slidable longitudinally relative to the support arm 1 and is mounted therein through the intermediary of a hydraulic ram 5. The piston rod 6 of the ram 5 is attached to the root portion 4, whilst the cylinder 7 of the ram is fixed relative to the support arm 1. The support arm 1 and the cylinder 7 are pivotally connected through a horizontal pivot 8 extending transversely of the towing vehicle. The pivot 8 serves to mount the pick-up hitch 1 on a fixed part 9 which is secured at a convenient location to the towing vehicle.A bracket 10 fixed to the support arm 1 at a location remote from the pivot 8 projects upwardly for attachment in a manner known per se with the lifting hydraulics of the towing vehicle. The lifting hydraulics of the towing vehicle can therefore be used to pivot the pick-up hitch in a vertical plane between a lowered position as illustrated in the drawing and a raised or towing position in which the support arm 1 extends horizontally with the hook 3 being disposed rearwardly of the pivot 8 relative to the forward direction of the towing vehicle. A manually operable, remotely-controlled latch (not shown) may be provided for retaining the support arm 1 in the towing position. An example of such a latch is disclosed in EP-A-0138519. Such latch or a separate latch may be adapted to lock the towing element 2 mechanically relative to the support arm 1. This prevents towing forces from being applied to the ram 5.

The ram 5 is double-acting and is connected into the towing hydraulics to enable it to be operated by the driver of the vehicle. Extension of the ram 5 when the hitch is in its lowered position can be effected to the desired extent to enable the driver to retain a good vision of the hook and to place it in the best position having regard to factors such as tyre wear, size and pressure. Additionally, the ram 5 can be extended to dig the hook 3 into the ground for picking up a trailer arm which has become embedded in the ground.

Claims

CLAIMS:

1. A towing hitch having a towing element which is mounted on a support through the intermediary of a piston and cylinder device, the support being adapted to be pivotally mounted on a tractor or other towing vehicle for pivotal movement in an upright plane, the arrangement being such that the distance between the towing element and the pivotal attachment of the support to the tractor can be varied by operation of the piston and cylinder device.

2. A towing hitch as claimed in claim 1, wherein the support is provided with a formation thereon disposed in spaced relationship from the axis of the pivot, said formation being attachable to means for pivoting the support about said pivot.

3. A towing hitch as claimed in claim 2, wherein said means takes the form of existing hydraulics on the towing vehicle.

4. A towing hitch as claimed in claim 1, 2 or 3, wherein the support takes the form of an arm from a pivot-remote end of which the towing element extends.

5 < A towing hitch substantially as hereinbefore described with reference to the accompanying drawing.