GB1575164A

GB1575164A - Coupling device

Info

Publication number: GB1575164A
Application number: GB1158578A
Authority: GB
Original assignee: Amazonen Werke H Dreyer SE and Co KG
Current assignee: Amazonen Werke H Dreyer SE and Co KG
Priority date: 1977-03-24
Filing date: 1978-03-23
Publication date: 1980-09-17
Also published as: CA1093372A; DE2712960C3; DE2712960A1; DE2712960B2

Description

(54) COUPLING DEVICE (71) We, AMAZONEN-WERKE H.

DREYER, G.m.b.H., & Co., KG, Am Amazonenwerk, 4507 Hasbergen-Gaste, Federal Republic of Germany, a German Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly dei scribed in and by the following state ment: - The present invention relates to a coupling device which is particularly suitable for coupling agricultural attachments to, for example, a tractor.

A tow bar which is fitted with a coupling element and which can be displaced both longitudinally and transversely within certain limits is known. Such a device can be locked in its central position.

One such device of this type has an elongate trapezoidal frame member pivotally mounted on the attachment about a vertical axis, which frame member is traversed by a longitudinally extending tow bar. A guide device is provided for the tow bar. In its simplest form, this guide device comprises two guide tracks located within the frame and a guide member which is rotatably mounted on the front end of the frame and is provided with guide rollers. The tow bar can be locked in its central position by means of a locking device located on the rear of the frame.

Such a device is intended to facilitate the coupling of an attachment to a traction vehicle. The tractor need only be driven generally towards the coupling device until the attachment is located in the area of movement of the coupling element of the coupling device. This can be easily achieved even if neither the coupling element of the tractor nor the coupling device of the attachment are visible from the driving seat of the tractor.

However, such an arrangement is a complicated, and therefore costly, structure.

Moreover, the elongate frame of the coupling device, if used with certain attachments such as seed drills, prevents the attachment and tractor being located close together. This disadvantage can be overcome by using a tow bar which only projects slightly beyond the front of the frame.

However, this increases the turning circle of the tractor in such a manner that the tractor has a very wide turning circle at the ends of the field which means that parts of the field may remain untreated.

The present invention seeks to provide a coupling device which is simpler in construction and easier to use than known devices.

In accordance with the present invention there is provided a coupling device suitable for an agricultural attachment comprising a tow bar provided at one end with a coupling element for connection to a towing device, a guide device for permitting longitudinal and transverse displacement of the tow bar within predetermined limits, the tow bar being lockable in a central position, wherein the guide device comprises a guide member rigidly connected to the tow bar and projecting laterally therefrom and a support member one end of which is pivotally mounted on one end of the guide member and the other end of which is pivotally mounted on a frame part of the attachment, the support member, in the locked position of the tow bar, projecting on either side of the tow bar.

By so doing, the dimension of the frame of the coupling device in the direction of travel may be kept very short and may even be a simple cross-support comprising a single support member pivotally mounted on the frame of the attachment.

Moreover, if the attachment is of the single-axle type, no frame whatsoever is required for the coupling device. Instead the frame section on which the support for the guide device is pivotally mounted form part of the frame of the implement. A narrow turning circle of the tractor and attachment is thus obtained, the radius of the turning circle being dependant only on the length of the tow bar.

In a preferred embodiment of the in vention, a locking member is provided on lhe "tow bar and at least one displaceable locking lever is pivotally mounted on the frame part, the lever having a projecting portion which co-operates with the locking -mernber, the locking lever being connected to a resilient element acting in a direction towards the locking member whereby the pivotal movement of the locking lever is limited in a forward direction by a stop member against the tension of the resilient element projecting portion of the locking lever having a frontal surface which ex tends diagonally. Thus, in a simple man ner, the tow bar may be locked securely in position so that the driver only has to -leave the tractor to effect the actual coupling operation, that is to say, to connect the coupling element of the tractor to the coupling device of the implement.

If the coupling element of the tow bar, in its locked position, is located along the medial line drawn between the two pivotal mountings for the support member, the tow bar is reliably guided into its locked position, after the coupling has been effec ted by reversing the tractor. This guidance is further improved if a stop member is provided for preventing the support from pivoting through an angle of more than 60 relative to its locked starting position.

By providing such an -arrangement, the support, even if acted upon by a force tending to diagonally push it outwardly during reversing of the tractor, cannot be pivoted into a position in which the tow bar cannot be locked. If the tractor is reversed diagonally to the implement to be coupled thereto, then after the coupling has been effected, the tractor need only be driven forwardly a short distance to cause support of the coupling device to abut against the stop. In this position, both the coupling element of the tow bar and the bearing of the guide member assume posi tions in front of the central region of the coupling device and, because of this, during further reversing, is reliably moved into its locking position.

When driving at speed over uneven ground, the locking lever may become acci dentally detached from the locking mem ber. To prevent this happening the inven tion provides, in a desired embodiment, a locking pin for locking the locking lever in position with respect to the support mem ber and to the tow bar. It is preferred if - a locking lever is located above the support member and tow bar and is non-rotatably connected to an identical locking lever loca ted below the support and tow bar, the locking member in such a case, projecting through the tow bar.

If - the locking lever located above the support and the tow bar has a freely upwardly projecting handle member mounted thereon, actuation of the locking lever or levers during the uncoupling of the attachment is made easier.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which Fig. 1 is a plan view of a coupling device in accordance with the present invention, the device being shown in its locked state; Fig. 2 is a sectional view taken along the line A-B of Fig. 1; and Fig. 3 is a plan view of the coupling de -vice shown in Figs. 1 and 2 in its unlocked state.

A coupling device as shown in Figs. 1 to 3 includes a tow bar 1 which, at one end, is provided with a coupling element 2 for connection to, for example, a tractor. At its other end, the tow bar 1 is connected to a guide device 3. This guide device comprises a bifurcated guide member 4 which is welded to the tow bar 1 and projects laterally therefrom, and a support member 5, one end of which is pivotally mounted on the free end of the guide member 4 by means of a bearing 6. In the locked position shown in Fig. 1, the mounting 6 for the support member 5 is located on one side of the tow bar 1 and the member 5 extends beyond the tow bar 1. The other end of the member 5 is pivotally mounted, by means of a bearing 7, to a frame part 8 which is connected in any suitable manner to an attachment (not shown) to be coupled to the tractor. Bl the position shown in Fig. 1, the coupling element 2 is accurately located on the medial line 10, forwardly in the direction of travel shown by the arrow 9, drawn between the two bearings 6 and 7 for ti support member 5.

Moreover, a locking member 11 is provided on the tow bar 1 which projects from the tow bar on both its upper and lower faces. In the retracted position of the device, the member ]1 is located adjacent to the support member 5, so that the tow bar 1 cannot be pivoted rearwardly beyond the support member 5. On the frame part 8, that is to say, rearwardly of the tow bar 1, a pin 12 is rotatably mounted, the ends of this pin 12 projecting from both the upper and lower surfaces of the frame part 8. A forwardly extending locking lever 13 is secured to each end of the pin 12. Each locking lever 13, at its front end, has a projecting portion 14 which can be pivoted around the projecting portions of the lock ing member 11. To prevent the locking levers 13 from being pivoted from their forwardly projecting position towards the bearing 7 for the support member 5, the levers 13 are interconnected by a stop member 15 located adjacent the frame part B. The ends of this member 15 project above and below the part 8 and a resilient element 16 is connected to each such end.

The !other end of each resilient element 16 is retained on the frame part 8, and the elements 16 therefore each exert a force on the locking levers 13 in the direction of their abutment with the locking member 11 or with the stop member 15.

To obtain an automatic retraction of the locking lever 13 against the force of the resilient element 16 during the locking operation, the projecting portion 14 of each locking lever 13 is provided with a diagonally extending forward edge 17. An upwardly projecting handle member 18 is mounted on the upper locking lever 13.

For ensuring the security of the tow bar 1 in its locked position, the lower portion of the tow bar 1, the central region of the support member 5 and the locking levers 13 have bores 19 formed therein which, in the locked position of the device, are aligned and through which in the locking position of a locking pin 20 can be inserted. When the locking pin 20 is not in use, it may be inserted in a sleeve member 21 welded to the frame part 8. Finally, a stop member 22 is provided forwardly of the bearing 7 on the frame part 8 which stop member 22 prevents the support member 5 from being pivoted from its locked position through an angle a greater than 60".

The coupling of an attachment to a tractor will now be described. Firstly, the tractor is driven towards the coupling device to such an extent until its coupling elements are located within the limits 23, shown in broken lines in Fig. 2 of movement of the coupling element 2. Since this is a substantial area, the tractor driver is able to sufficiently accurately position his vehicle even if he is una'ole to see the coupling device.

The locking pin 20 is then removed from the bores 19, the upper locking lever 13 is pivoted rearwardly until its projecting portion 14, and the projecting portion 14 of the lower locking lever 13, become detached from the locking member 11. The tow bar 1 is drawn forward to such an extent that the coupling element 2 can be coupled to the coupling elements of the tractor. It is relatively rare, in practice, that the tractor is accurately centrally aligned with the coupling device, it is generally necessary once the tractor has had the attachment connected thereto, for the tractor to be driven forwardly in a straight line until the coupling device assumes the extended position shown in Fig.

3. In this position, the support member 5 abuts against the stop member 22, whilst the bearing 6 for the member 5 and the coupling element 2 are both located.accura- tely on the medial line 10.

The tractor is then reversed which.causes -the tow bar 1 and the guide member 4 :to be pivoted inwardly in the direction of the arrow 24, and the support member 5 to be pivoted in the direction of the arrow 25.

During the latter part of such pivotal movement, the stop member 11 strikes against the inclined surfaces 17 of the locking levers 13 and urges them against the action of the resilient elements 17, back until the locking member 11 is located in front of the slot in the projecting portion 14. The levers 13 are then drawn, by the resilient elements 16, into the locked position shown in Fig. 1. The locking pin 20 may then be re-inserted into the aligned bores 19.

1. A coupling device suitable for an agricultural attachment comprising a tow bar provided at one end with a coupling element for connection to a towing device, a guide device for permitting longitudinal and transverse displacement of the tow bar within pre-determined limits, the tow bar being lockable in a central position, wherein the guide device comprises a guide member rigidly connected to the tow bar and projecting laterally therefrom and a support member, one end of which is pivotally mounted on a frame part of the attachment, the support member, in the locked position of the tow bar, projecting on either side of the tow bar.

2. A coupling device as claimed in claim 1 wherein a locking member is provided on the tow bar and at least one displaceable locking lever is pivotally mounted on the frame part, the lever having a projecting portion which co-operates with the locking member, the locking lever being connected to a resilient element acting in a direction towards the locking member, whereby the pivotal movement of the locking lever is limited in a forward direction by a stop member against the tension of the resilient element, the projecting portion of the locking lever having a frontal surface which extends diagonally.

3. A coupling device as claimed in claim 1 or 2 wherein the coupling element of the tow bar for connection to the towing device is located on the medial line drawn forwardly in the direction of travel between the two pivotal mountings of the support member in the locked position of the tow bar.

4. A coupling device as claimed in any one of claims 1 to 3 wherein a stop member is provided for limiting the pivotal movement of the support member to an angle of 60 relative to its position in the locked position of the device.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. B. The ends of this member 15 project above and below the part 8 and a resilient element 16 is connected to each such end. The !other end of each resilient element 16 is retained on the frame part 8, and the elements 16 therefore each exert a force on the locking levers 13 in the direction of their abutment with the locking member 11 or with the stop member 15. To obtain an automatic retraction of the locking lever 13 against the force of the resilient element 16 during the locking operation, the projecting portion 14 of each locking lever 13 is provided with a diagonally extending forward edge 17. An upwardly projecting handle member 18 is mounted on the upper locking lever 13. For ensuring the security of the tow bar 1 in its locked position, the lower portion of the tow bar 1, the central region of the support member 5 and the locking levers 13 have bores 19 formed therein which, in the locked position of the device, are aligned and through which in the locking position of a locking pin 20 can be inserted. When the locking pin 20 is not in use, it may be inserted in a sleeve member 21 welded to the frame part 8. Finally, a stop member 22 is provided forwardly of the bearing 7 on the frame part 8 which stop member 22 prevents the support member 5 from being pivoted from its locked position through an angle a greater than 60". The coupling of an attachment to a tractor will now be described. Firstly, the tractor is driven towards the coupling device to such an extent until its coupling elements are located within the limits 23, shown in broken lines in Fig. 2 of movement of the coupling element 2. Since this is a substantial area, the tractor driver is able to sufficiently accurately position his vehicle even if he is una'ole to see the coupling device. The locking pin 20 is then removed from the bores 19, the upper locking lever 13 is pivoted rearwardly until its projecting portion 14, and the projecting portion 14 of the lower locking lever 13, become detached from the locking member 11. The tow bar 1 is drawn forward to such an extent that the coupling element 2 can be coupled to the coupling elements of the tractor. It is relatively rare, in practice, that the tractor is accurately centrally aligned with the coupling device, it is generally necessary once the tractor has had the attachment connected thereto, for the tractor to be driven forwardly in a straight line until the coupling device assumes the extended position shown in Fig. 3. In this position, the support member 5 abuts against the stop member 22, whilst the bearing 6 for the member 5 and the coupling element 2 are both located.accura- tely on the medial line 10. The tractor is then reversed which.causes -the tow bar 1 and the guide member 4 :to be pivoted inwardly in the direction of the arrow 24, and the support member 5 to be pivoted in the direction of the arrow 25. During the latter part of such pivotal movement, the stop member 11 strikes against the inclined surfaces 17 of the locking levers 13 and urges them against the action of the resilient elements 17, back until the locking member 11 is located in front of the slot in the projecting portion 14. The levers 13 are then drawn, by the resilient elements 16, into the locked position shown in Fig. 1. The locking pin 20 may then be re-inserted into the aligned bores 19.

5. A coupling device as claimed in any

preceding claim wherein the locking lever, in the locked position of the tow bar, is additionally lockable to the support member and to the tow bar by a locking pin.

6. A coupling device as claimed in any preceding claim wherein one locking lever is located above the support and tow bar and is non-rotatably connected to a second locking lever located below the support member and tow bar, the locking member projecting through the tow bar.

7. A coupling device as claimed in claim 6 wherein a freely upwardly projecting handle member is mounted on the lock.

ing lever located above the support and tow bar.

8. A coupling device constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.