GB2227151A

GB2227151A - Releasable coupling device for trailed agricultural implement

Info

Publication number: GB2227151A
Application number: GB8921291A
Authority: GB
Inventors: Magne Skjaeveland
Original assignee: Kverneland AS
Current assignee: Kverneland AS
Priority date: 1989-01-19
Filing date: 1989-09-20
Publication date: 1990-07-25
Anticipated expiration: 2009-09-20
Also published as: GB8921291D0; GB2227151B; SE8900191L; SE8900191D0; SE462886B; DE4001267A1; DE4001267C2; FR2641666A1

Description

RELEASABLE COUPLING DEVICE FOR TRAILED AGRICULTURAL IMPLEMENT This

invention relates to a releasable coupling device for coupling a first trailed agricultural implement behind a second trailed agricultural implement which is int.ended to be drawn behind a tractor.

The invention has been developed particularly, though not exclusively, with a view to providing a releasable coupling device which can couple an agricultural implement behind a tractordrawn plough, and especially a reversible plough.

It is often desirable to connect several tractor-drawn agricultural implements together e.g. to couple-up a trailed implement behind a plough, so that several different working operations can be carried out during one pass of the tractor and combination. However, this may be difficult to accomplish when an implement is to be connected to a reversible plough, since the plough has to be lifted out of the ground at the end of each furrow. reversed and then positioned again for ploughing in the opposite direction. Prior to the reversal of the plough, the connection between the plough and the following implement must be released, and when the reversal of the plough has been effected, the trailed implement has to be connected to the plough again.

It is known to arrange at each end of the trailed implement a pull or drawbar having a hook adapted to be connected to a reversible plough, and in which the hook is adapted to engage a carrier arm equipped with catch dogs and attached to the reversible plough. However, as yet it has not been possible to construct a releasable coupling device which can release the hook from the carrier arm in a simple manner again. and in which the coupling device is small, simple and functionally reliable in all circumstances.

2 The invention therefore seeks to provide a releasable coupling device having improved operation over the known devices.

According to the invention there is provided a releasable coupling device for coupling a first trailed agricultural implement behind a second trailed agricultural implement which is to be drawn behind a tractor, said coupling device comprising:

a connector link having a first end which is adapted for coupling with the second implement and a second end which is adapted to be coupled with a draw hitch provided on the first implement; and, a releasable coupling provided at said second end of the connector link which comprises:

a coupler having a forwardly facing V-shaped guide engageable with the draw hitch to couple the first implement with the connector link; a receiving slot provided in the coupler and arranged to receive the draw hitch as it is guided thereto by the guide; ' a rocker pivotally mounted on the coupler for movement between an arresting position in which it extends across the receiving slot so as to be engageable with the draw hitch in order to transmit traction from the connector link to the first implement when the hitch is coupled with the connector link, and a withdrawn position which permits the draw hitch to move along the slot in order to release the coupling of the first implement from the connector link; and.

means for moving the rocker between its two positions.

Preferably. the coupler is formed by a pair of dogs which define a Vshape, as seen in side view, and which converges towards the receiving slot which extends rearwardly therefrom through the middle of the coupler. At least one of the dogs may be substantially U-shaped or channel-shaped in form. with the open part of this form ( k 3 facing rearwardly with respect to the direction of traction.

The means to operate the rocker may be mounted in said one dog, and may take the form of a fluid pressure operated cylinder which is operable to move the rocker to the withdrawn position, or in fact this cylinder may be double acting so that it is capable of moving the rocker to and fro between the withdrawn position and the arresting position. In the case in which the cylinder is only operable to move the rocker to the withdrawn position. said means may include a spring which is coupled with the rocker and which is arranged to bias the rocker towards the arresting position.

Conveniently, the dogs are each secured to one end of a respective one of a pair of parallel mounting plates which are secured to the rear end of the connector link so as to form one limb of an angle of which the link forms the other limb. The mounting plates may be spaced apart so as to define a rear part of said receiving slot.

Conveniently. the rocker has a stop which is engageable with an abuttment provided on the coupler in order to define the arresting position.

In one preferred use of the releasable coupling device of the invention, the first end of the connector link can be pivotally connected to a swing arm of a reversible plough which forms said second agricultural implement, and the second end of the connector link can be coupled with a towing hitch e.g. a book at the forward end of a drawbar coupled with a packer. A fluid pressure cylinder may be provided to vary the inclination of the connector link to the swing arm by pivoting about its pivotal connection thereto.

The packer may be provided with a pair of drawbars, one at each side thereof. to enable the direction in which the packer is pulled to be reversed with each reversal of the plough.

1 4 One embodiment of releasable coupling device according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a top plan view of a releasable coupling device according to the invention being used to coup3e together two separate agricultural implements which are drawn behind a tractor; Figure 2 is a plan view. to a larger scale, showing a connector link of a coupler which forms part of the coupling device; and, Figure 3 is a side view. as viewed on the arrows A-A in Figure 2, to further enlarged scale, showing the coupling and uncoupling operation of the device.

Referring now to the drawings. Figure 1 shows a top plan view of a reversible plough connected to a tractor. in which the upwardly directed plough bodies are omitted for the sake of clarity. and in which a socalled packer is connected to the reversible plough by means of a connector link in the form of a carrier arm equipped with catch dogs and an uncoupling arrangement. and which is pivotally connected at its forward end to the reversible plough. and at its rear end to a hitch of a forwardly projecting drawbar attached to a packer. In Figure 3. the connector link is omitted for ease of understanding.

In the drawings, reference numeral 1 denoted a tractor to which a reversible plough 2 is connected. A packer 3 is connected to the reversible plough 2 by means of a pull arm or drawbar 4 pivotally attached to the packer and having a hook 5, and a connector link in the form of a carrier arm 8 equipped with catch dogs 6, 6' and a disconnection device 7. By means of a bolt 9. the carrier arm 8 is pivotally attached to an arm 10 fastened to the reversible plough 2. By means of an adjusting means, e.g. a hydraulic cylinder 11. the carrier arm 8 can be brought to pivot about the bolt 9 in order to be rotated inwards against the reversible plough 2 before reversal of the same, and in order to arrive in the correct position for being connected to the hook 5 on the pull arm 4 of the packer 3.

In addition to the already mentioned pull arm 4 having a hook 5 and being fastened to one end of the packer 3, a second pull arm 4' having a hook 5' is attached correspondingly at the opposite end of the packer and becoming active whenever the reversible plough 2 has been reversed and as to be connected to the packer 3 again for driving in the opposite direction. The pull arms 4, 4' are formed telescopically, so that their length may be varied. The pull arms 4, 4' are mutually connected by means of a wire 12 guided through a guide 13 along one side of the packer 3, so that the inactive pull arm turns towards the guide 13 whenever the hook on the other pull arm engages the carrier arm 8, whereby the connected pull arm is rotated out in the driving direction, as shown in Figure 1.

The catch dogs 6. 6' form in front a V-shape (as seen in side view) throughgoing slot 14 in the bottom, so as to form a guide for the hook 5 or 5' respectively, which can be caught easily during the connection of packer 3 to the plough and automatically guided into the slot 14 to rest against one side of a rocker arm 15 pivotally supported on a shaft 16 attached to the catch dog 6'.

The pull arms 4, 4' of the packer 3 and the carrier arm 8 of the reversible plough 2 must be properly adjusted in relation to plough size and ploughing width. The packer 3 is alternately pulled by the first or second pull arm 4, 4'.

Each of the catch dogs 6, 6' is made from steel plate being bent into Ushape having parallel side portions, and wherein the open part of the Ushape faces backwards in relation to the driving direction. Further, each of the two catch dogs 6. 6' are welded to one end of its associated one of two parallel plate parts, 17 and 18, respectively. The other end of the plate parts 17, 18 is 6 pivotally attached to the outer end of the carrier arm 8. so that they form one leg of an outwards directed open angle wherein the carrier arm 8 forms the other leg. The plate parts 17, 18 form the rearmost end of the slot 14 between the catch dogs 6 and 6'.

The shaft 16 about which the rocker arm 15 rotates. is attached to the two side portions of the catch dog 6', and the rocker arm is positioned between said side portions. The other end of the rocker arm 15 is attached to one end -of a spring 19, the other end of which is attached to a bolt 20 fastened between the side portions of the catch dog 6'. The spring 19 normally keeps the rocker arm 15 in closed position, as shown in Figure 3. A power transmitter in the form of a single-acting hydraulic cylinder 21 is pivotally attached to a second bolt 22 also fastened between the side portions of the catch dog 6', and the free end of the piston rod 23 of the hydraulic cylinder 21 is attached to the other side of the rocker arm 15. The other side of the rocker arm 15 is provided with a stop lug 24 which, when the rocker arm 15 occupies the closed position, is adapted to rest against a third bolt 25 fastened between the side portions of the catch dog 6.

Whenever the packer 3 is to be released from the reversible plough 2 prior to the latter being lifted up from the ground and reversed, the hydraulic cylinder 21 is activated and causes the rocker arm 15 to rotate about the shaft against the force of the spring 19. The stop lug 24 of the rocker arm 15 is thereby caused to be rotated away from its resting position against the third bolt 25, and the end of the rocker arm 15 extending up into the slot 14 between the catch dogs 6, 6' and engaging the hook 5 or 5', respectively, of the pull arm 4 or 4', respectively, is caused to rotate out of engagement with the hook 5 or 5', respectively. and down between the side portions of the catch dog 6'. Thereby, the slot 14 becomes entirely open, and the hook 5 or 5', respectively. may unimpeded slide out (1 1 7 from the slot 14 when the tractor 1 together with the plough 2 drives further forwards, whereby there no longer exists any connection between the plough 2 and the packer 3. When the hydraulic cylinder 21 no longer is activated, the spring 19 pulls the rocker arm 15 and the piston rod 23 of the hydraulic cylinder 21 back into the original position, as shown in Figure 3.

The disclosed embodiment of releasable coupling device according to the invention offers great advantages in relation to previously known devices. When the pull arm 4 or 4', respectively, of the packer 3 during connection is being caught and kept in place in the carrier arm 8 of the reversible plough 2, as shown in Figure 3, no force from the hydraulic cylinder 21 or the spring 19 is required for keeping the hook 5 or 5', respectively, on the pull arm 4 or 4', respectively, on the packer, in place in its engagement with the rocker arm 15 of the carrier arm 8. This engagement will be maintained as long as the tractor does not reverse, and until the rocker arm 15 is rotated out of said engagement by means of the hydraulic cylinder 21.

Other advantages are that no accurate bearings suspensions are required, and between parts movable in relation to each other one may use so large clearances that wedging can not occur in any position.

Further advantages are that only the spring force 19 and the friction forces have to be overcome through the force of the force transmitter 21 whenever the rocker arm 15 is to be rotated out of its engagement with the hook 5 or S' respectively, whereby only a small force transmitter 21 is needed requiring a minor space between the side portions of the catch dog 6'. Furthermore, the small volume occupied by the operating components of the device enables it to be well protected between the side portions of the catch dog 6.

8

Claims

1. A releasable coupling device for coupling a first trailed agricultural implement behind a second trailed agricultural implement which is to be drawn behind a tractor, said coupling device comprising:

a coupler having a forwardly facing V-shaped guide engageable with the draw hitch to couple the first implement with the connector link; a receiving slot provided in the coupler and arranged to receive the draw hitch as it is guided thereto by the guide; a rocker pivotally mounted on the coupler for movement between an arresting position in which it extends across the receiving slot so as to be engageable with the draw hitch in order to transmit traction from the connector link to the first implement when the hitch is coupled with the connector link, and a withdrawn position which permits the draw hitch to move along the slot in order to release the coupling of the first implement from the connector link: and, means for moving the rocker between its two positions.

2. A releasable coupling device according to Claims 1. in which the coupler is formed by a pair of dogs which define a V-shape, as seen in side view, and which converge towards said receiving slot which extends rearwardly therefrom through the middle of the coupler.

3. A releasable coupling device according to Claim 2, in which at least one of the dogs has a substantially Ushaped or channelshaped form, with the open part of this 9 form facing rearwardly with respect to the direction of traction.

4. A releasable coupling device according to Claim 3, in which means for operating said rocker is mounted in said one dog.

5. A releasable coupling device according to any one of Claims 2 to 4, in which the dogs are each secured to one end of a respective one of a pair of parallel mounting plates which are secured to the rear end of said connector link so as to form one limb of an angle of which the connector link forms the other limb.

6. A releasable coupling device according to Claim 5, in which the mounting plates are spaced apart so as to define a rear part of said receiving slot.

7. A releasable coupling device according to any one of the preceding Claims, in which the rocker has a stop engageable with an abuttment provided on the coupler in order to define the arresting position.

8. A releasable coupling device according to any one of the preceding Claims, in which said means for moving the rocker comprises a fluid pressure operated cylinder which is operable to move the rocker to the withdrawn position.

9. A releasable coupling device according to Claim 8, in which said means includes a spring coupled with the rocker and arranged to bias the rocker towards the arresting position.

10. A releasable coupling device according to Claim 8, in which the cylinder is double acting so as to be operable to move the rocker to and fro between the arresting position and the withdrawn position.

11. A releasable coupling device according to any one of the preceding Claims, in which the first end of the connector link is adapted to be pivotally connected to a swing arm of a reversible plough, and includes a fluid pressure cylinder operable to vary the inclination of the connector link to the swing arm.

1 4

12. A releasable coupling device according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

4 Published 1990 atThePatentOffice, State House, 66.71 High Holborn, LondonWC1R4TP. Further copies maybe obtainedfrom The Patent Office Sales Branch. St Mary Cray. OrpingLon, Kent BR5 3RD- Printed by Multiplex techniques ltd. St Mary Cray, Kent, Con. 1,87