The present invention relates to a coupling arrangement for a device for steering an axle or axles on a trailed implement and in particular to a coupling arrangement for connecting the steering device to a towing vehicle, such as, for example but not limited thereto, a tractor.

Various hitches, including automatic pick up hitches are known for connecting a towing vehicle, such as a tractor to a trailed implement, such as a trailer. The connection between the hitch and the implement normally includes an articulated joint to enable the implement to follow the vehicle around bends and over uneven terrain. One such pick up hitch is described in GB 2429195 B. However, a separate steering device is usually provided for steering one or more axles of the implement to follow the path of the towing vehicle.

One such known steering arrangement comprises a signal arm provided between the trailed implement and the pick up hitch which is mounted on the vehicle. One end of the arm is connected to one or more axles and the other end is connected to the hitch via an articulated coupling, such as for example a coupling known as a "ball and spoon" coupling, i.e. a ball mounted on the hitch and a spoon placed over the ball and manually clipped or otherwise securely connected to the ball. Manual intervention is also required to disconnect the ball and the spoon.

An improvement to the above system provided an automatic locking function whereby a locking member would be automatically forced into a locked position over the coupling to prevent the coupling from disengaging. However, manual intervention is still required to unlock the locking member and to disengage the coupled members of the coupling.

It is an object of the present invention to provide a coupling arrangement for a device for steering an axle on a trailed implement having an automatic locking and unlocking functionality.

Accordingly, the present invention provides a coupling arrangement for a device for steering an axle on a trailed implement, the coupling arrangement comprising

a first coupling member mountable on a base body mountable on a towing vehicle, the first coupling member being releasably engageable with a second coupling member to form an articulated joint for controlling the axle in accordance with movements of the towing vehicle, the second coupling member being mountable on a device for steering an axle on a trailed implement; and

a latching means arranged to cooperate with the first and the second coupling members for releasably locking the first and the second coupling members in their engagement, wherein the latching means is operable between a fastening mode and a release mode; and

the latching means comprises a catch member positionable by the latching means adjacent the first and second coupling members in a coupling engaging mode so as to prevent the first and the second coupling members from disengaging from each other and the catch member is also positionable by the latching means in a position away from the first and the second coupling members in a coupling release mode to enable disengagement of the first and the second coupling members.

Preferably, the latching means comprises a bias means and the catch member is normally biased into the coupling engaging mode, the catch member being movable into the coupling release mode by application of a force to the latching means so as to overcome the bias force of the bias means wherein the bias means is configured to return latching means together with the catch member into the coupling engaging mode upon withdrawal of the force.

Preferably, the latching means comprises a primary catch member for releasably locking a primary coupling member mountable on the base body with a corresponding connecting member of a trailed implement to form an articulated towing joint, wherein the latching means is movable between the fastening mode and the release mode upon application of a force to the primary catch member and wherein the catch member of the coupling arrangement of the invention is connected with the latching means so as to be moved between the coupling engaging mode and the coupling release mode by the latching means when the latching means is being operated upon by the primary catch member.

Preferably, the catch member is provided in the form of an extension to the primary catch member or to the latching means. Further preferably, the catch member is mounted on an extension arm extending from the latching means or from the primary catch member. Preferably, the first coupling member is provided on an extension to the base body or the primary coupling member. Further preferably, the first coupling member is mounted on an extension arm extending from the base body or from the primary coupling member. Preferably, the coupling arrangement of the invention comprises a pair of catch members, preferably, provided at opposing sides of the primary catch member.

Preferably, the coupling arrangement of the invention comprises a pair of first coupling members, preferably, provided at either side of the primary coupling member.

In one arrangement, the coupling arrangement of the invention is mountable on a pick-up hitch of a towing vehicle via the base body. Preferably, the base body comprises a mounting bar. In another variation, the base body comprises a pick-up hitch of a vehicle.

Preferably, the biasing means is connected between the latching means and the base body. In one variation, the biasing means comprises first and second ends and is connected to the base body at each end and to the latching means at a portion intermediate the ends. In another variation, the biasing means comprises first and second ends and is connected to the latching means at one end and to the base body at the other end.

Preferably, the primary latching means comprises a latching member. In one arrangement, the latching member is pivotally mounted with respect to the primary coupling member. In another arrangement the latching member is slidably mounted with respect to the primary coupling member.

Preferably, latching member comprises a base body mountable portion and a free portion.

In one arrangement, the latching member comprises a generally inverted U-shaped or Ω- shaped member pivotally attached to the base body at its ends to define a free portion spaced apart from the base body mounted ends. Preferably, the primary catch member is provided about the free portion of the latching member.

Preferably, the biasing means comprises a biasing member comprising first and second ends, e.g. a spring, and the biasing member is connected to the base body at one end and to the latching member between the base body mounted portion and the free end portion of the latching member.

In use, the latching member is moved into the releasing mode by a counterforce acting on the primary catch member from the connecting member of the trailed implement as the primary catch member is being pushed into contact with the connecting member laterally and/or upwardly in relation to the connecting member, thereby providing a clearance for the connecting member to enable engagement of the primary coupling member with the connecting member and, simultaneously, of the first coupling member with the second coupling member. Upon completion of engagement of the primary coupling member with the connecting member and of the first coupling member with the second coupling member, the primary catch member becomes disengaged from the connecting member and, accordingly, the latching member returns into the fastening mode by the bias means, whereby the primary catch member and the catch member are moved back into the coupling engaging mode, whereby the primary coupling member is retained in an engagement with the connecting member by the primary catch member and the first coupling member is retained in an engagement with the second coupling member by the catch member. In one optional arrangement, the latching member is movable into the releasing mode by pulling a release cord connected about the free portion of latching member thus overcoming the bias force of the bias means and moving the primary catch member away from the primary coupling member and the catch member from the first coupling member. Preferably, the catch member and the primary catch member are positioned in the coupling engaging mode in relation to the respective first coupling member and the primary coupling member so that upon a downward or downwardly lateral movement of the coupling arrangement with respect to the connecting member, the connecting member applies an upward or upwardly lateral counterforce to the primary catch member thereby moving the latching member into the release mode and thereby providing a clearance for the connecting member to enable lateral and/or upward withdrawal of the connecting member from its engagement with the primary coupling member or lateral and/or downward withdrawal of the primary coupling member from its engagement with the connecting member; and, at the same time, lateral and/or upward withdrawal of the second coupling member from its engagement with the first coupling member or lateral and/or downward withdrawal of the first coupling member from its engagement with the second coupling member.

Preferably, the catch member is positioned substantially above the first coupling member in the coupling engaging mode. Likewise, preferably, the primary catch member is positioned substantially above the primary coupling member in the coupling engaging mode.

In use, the connecting member and the coupling arrangement of the invention mounted on a pick-up hitch of a drawbar are first aligned at a substantially the same level above the ground. Then, the vehicle together with the drawbar is driven towards the connecting member so that the connecting member pushes the primary catch member laterally and/or upwardly away from primary coupling member. Simultaneously, the catch member is moved laterally and/or upwardly away from the first coupling member. Once the primary catch member is pushed sufficiently away from the primary coupling member to provide a clearance for the connecting member to enter into engagement with the primary coupling member, the connecting member and the primary coupling member snap into engagement and at the same time the connecting member becomes disengaged from the primary catch member so that the latching member snaps back into the fastening mode whereby the primary catch member locks the primary coupling member and the connecting member in their engagement. Simultaneously, the second coupling member and the first coupling member snap into engagement and the catch member is moved by the latching means into the coupling engaging mode and locks the first and second coupling members in their engagement. In order to decouple the first coupling member from the second coupling member and the primary coupling member from the connecting member, the pick-up hitch is lowered, whereby the connecting member applies an upward and/or lateral force to the primary catch member whereby the latching member is moved into the release mode. When the primary catch member is sufficiently moved away from the primary coupling member to provide a clearance for the connecting member to disengage from the primary coupling member, the vehicle is driven away from the connecting member whereby the primary coupling member is withdrawn laterally and/or downwardly from the engagement with the connecting member and, simultaneously, the first coupling member is withdrawn laterally and/or downwardly from the engagement with the second coupling member. Optionally, the latching member may be movable into the release mode by pulling a release cord connected to the latch member thereby overcoming the bias force of the bias means and moving the primary catch member away from the primary coupling member.

In a preferred embodiment, the first coupling member comprises a ball member. Preferably, the primary coupling member also comprises a primary ball member.

Preferably, the second coupling member defines a recess configured for receiving the ball and includes a surface enabling a substantially spherical surface contact with the ball. Preferably, the second coupling member is substantially spoon shaped. Preferably, the connecting member also defines a recess configured for receiving the primary ball and includes a surface enabling a substantially spherical surface contact with the primary ball. Preferably, the connecting member is also substantially spoon shaped.

The invention will now be described with reference to the accompanying drawings which exemplify an embodiment of a coupling arrangement for a device for steering an axle on a trailed implement of the invention. In the drawings:

Figures 1 to 3 are respectively a rear view, a plan view, a perspective view and a side view of a coupling arrangement of the invention showing a latching means in a fastening mode; and

Figures 4 to 8 are respectively a side view, a rear view, a plan view and a perspective view of the coupling arrangement of the invention showing the latching means in a release mode.

A coupling arrangement for a coupling arrangement for a device for steering an axle on a trailed implement is indicated in the drawings by reference numeral 1.

The coupling arrangement 1 comprises a pair of substantially ball shaped first coupling members 10 mountable on a base body provided in the present embodiment in the form of a mounting bar 50 (although it will be appreciated that other forms of a base body are possible), which in turn is in use mounted on a pick-up hitch 51 , typically a pick up hitch of a drawbar of towing vehicle. The first coupling member 10 is reteasably engageable with a respective second coupling member 20 (Figures 1 and 6) to form an articulated joint for controlling the axle of the trailed implement in accordance with movements of the towing vehicle. The second coupling member 20 is mountable on a device for steering an axle on a trailed implement (not shown), which typically comprises a control rod connected to the axle. The second coupling member 20 is substantially spoon shaped and defines a recess (not shown) configured for receiving the substantially ball shaped first coupling member 10 and includes a surface enabling a substantially spherical surface contact with the first coupling member 10.

A latching means indicated generally 60 is arranged to cooperate with the first and the second coupling members 10, 20 for releasably locking the first and the second coupling members 10, 20 in their engagement. The latching means is operable between a fastening mode shown in Figures 1 to 4 and a release mode shown in Figures 5 to 8.

The latching means 60 comprises a catch member 30 positionable by the latching means 60 adjacent the first and second coupling members 10, 20 in a coupling engaging mode so as to prevent the first and the second coupling members 10, 20 from disengaging from each other. The catch member 30 is also positionable by the latching means 60 in a position away from the first and the second coupling members 10, 20 in a coupling release mode to enable disengagement of the first and the second coupling members 10, 20.

The latching means 60 comprises a bias means in the form of springs 40 in the present embodiment and the catch member 30 is normally biased into the coupling engaging mode by the latching means 60. The catch member 30 being movable by the latching means 60 into the coupling release mode by application of a force (indicated by arrow A in Figure 4) to the latching means 60 so as to overcome the bias force of spring 40. The spring 40 returns the latching means 60 together with the catch member 30 into the coupling engaging mode upon withdrawal of the force (the direction of the return is indicated by arrow B in Figures 5). The latching means 60 in the presently describe embodiment comprises an Ω-shaped latching member 62 pivotally mounted on the mounting bar 50 by ends 65 of the Ω- shaped latching member 62 so that the latching member 62 defines a free portion 63. The latching member 62 comprises a primary catch member 61 provided about the free portion 63 of the latching member 62. The primary catch member 61 operates to releasably lock a substantially ball shaped primary coupling member 64 mounted on the mounting bar 50 with a corresponding connecting member 70 (Figure 5) of a trailed implement to form an articulated towing joint. The latching member 62 is movable between the fastening mode and the release mode upon application of a force (indicated by arrow A in Figure 4) to the primary catch member 61.

The connecting member 70 is substantially spoon shaped and defines a recess configured for receiving the substantially ball shaped primary coupling member 64 and includes a surface enabling a substantially spherical surface contact with the primary coupling member 64.

The catch member 30 is mounted on an extension arm 31 extending from the latching member 62 so as to be moved between the coupling engaging mode and the coupling release mode by the latching member 62 when the latching member 62 is being operated upon by the primary catch member 61.

The first coupling member 10 is mounted on an extension arm 32 extending from the mounting bar 50.

The spring 40 has ends 41 and 42 and is connected to the mounting bar 50 by the ends 41 , 42 and by an intermediate portion to the respective end 65 of the latching member 62.

The catch member 30 is positioned substantially above the respective first coupling member 10 (and the respective second coupling member 20, when the first and second coupling members 10, 20 are engaged) in the coupling engaging mode. Likewise, the primary catch member 61 is positioned substantially above the primary coupling member 64 (and the connecting member 70, when the primary coupling member 64 and the connecting member 70 are engaged) in the coupling engaging mode. In use, the connecting member 70 and the coupling arrangement of the invention mounted on a pick-up hitch 51 of a drawbar are first aligned at a substantially the same level above the ground. Then, the vehicle together with the drawbar is driven towards the connecting member 70 so that the connecting member 70 pushes the primary catch member 61 laterally and upwardly (arrow A in Figure 4) away from primary coupling member 64. Simultaneously, the catch member 30 is moved laterally and upwardly (arrow A in Figure 4) away from the respective first coupling member 10. Once the primary catch member 61 is pushed sufficiently away from the primary coupling member 64 to provide a clearance for the connecting member 71 to enter into engagement with the primary coupling member 64, the connecting member 70 and the primary coupling member 64 snap into engagement and at the same time the connecting member 70 becomes disengaged from the primary catch member 61. The latching member 62 snaps back into the fastening mode whereby the primary catch member 61 locks the primary coupling member 64 and the connecting member 70 in their engagement. Simultaneously, the respective second coupling member 20 and the first coupling member 10 snap into engagement and the respective catch member 30 is moved by the latching member 62 into the coupling engaging mode and locks the first and second coupling members 10, 20 in their engagement. Preferably, the catch members 20 and the primary catch member 61 are positioned in the coupling engaging mode in relation to the respective first coupling members 10 and the primary coupling member 64 so that upon a downward or downwardly lateral movement of the coupling arrangement with respect to the connecting member 70, the connecting member 70 applies an upward or upwardly lateral counterforce to the primary catch member 61 thereby moving the latching member 62 into the release mode (arrow A in Figure 4) and thereby providing a clearance for the connecting member 70 to enable lateral and/or upward withdrawal of the connecting member 70 from its engagement with the primary coupling member 64 or lateral and/or downward withdrawal of the primary coupling member 64 from its engagement with the connecting member 70; and, at the same time, lateral and or upward withdrawal of the second coupling member 20 from its engagement with the first coupling member 10 or lateral and/or downward withdrawal of the first coupling member 10 from its engagement with the second coupling member 20.

In order to decouple the first coupling member 10 from the respective second coupling member 20 and the primary coupling member 64 from the connecting member 70, the pick up hitch 51 is lowered whereby the connecting member 70 applies an upward and lateral force (arrow A in Figure 4) to the primary catch member 61 thereby moving the latching member 72 is moved into the release mode. Simultaneously, the catch members 30 are moved away from the respective first coupling members 10 to provide a clearance for the second coupling members 20 to disengage from the first coupling member. When the primary catch member 61 is sufficiently moved away from the primary coupling member 64 to provide a clearance for the connecting member 70 to disengage from the primary coupling member 64, the vehicle is driven away from the connecting member 70 whereby the primary coupling member 64 is withdrawn laterally and/or downwardly from the engagement with the connecting member 70. Simultaneously, the first coupling member 10 is withdrawn laterally and/or downwardly from the engagement with the respective second coupling member 20.

Additionally, the latching member 62 may be movable into the release mode by pulling a release cord (not shown) connected to the latch member 62 thereby overcoming the bias force of the spring 40 and moving the primary catch member 61 away from the primary coupling member 64 and the first coupling member 10 from the respective second coupling member 20. The foregoing description of the preferred embodiments being provided merely for the purpose of illustration of the disclosure. Persons skilled in the art will appreciate that various modifications of the above-described embodiments not explicitly described herein are possible.