GB2330060A

GB2330060A - Actuating device for a coupling hook of a tractor

Info

Publication number: GB2330060A
Application number: GB9821327A
Authority: GB
Inventors: Herbert Coenen; Joachim Laubner; Juergen Vollmer; Kurt Kirschbaum
Original assignee: GKN Walterscheid GmbH
Current assignee: Walterscheid GmbH
Priority date: 1997-10-09
Filing date: 1998-10-02
Publication date: 1999-04-14
Anticipated expiration: 2018-10-02
Also published as: ATA155298A; ITMI982099A1; IT1302297B1; GB9821327D0; FR2769461A1; GB2330060A8; AT410743B; DE19744479C1; GB2330060B; FR2769461B1; NL1010121C2

Abstract

The invention relates to an actuating device for a coupling hook (6) of a lower link (7) of a tractor (1). The cable connected at one end to the actuating element (7) of the coupling hook (6) for the purpose of actuating the coupling hook (6) to is secured at its other end to a fixing point (9) of the tractor (1). To prevent the cable in the unloaded condition from getting entangled or damaged at other components, it is loaded by a tension spring (10) which transfers the cable (8) into a defined position. In this way it is ensured that the cable length required for operational purposes can be provided in order to prevent unintentional opening of the coupling hook and to achieve the required guiding conditions. By introducing a force, the amount of force required for lengthening the tension spring is kept small.

Description

2330060 t Title: ACTUATING DEVICE FOR A COUPLING HOOK OF A LOWER LINK

Description of Invention

The invention relates to an actuating device for a coupling hook of a lower link of an implement-attachment linkage of a tractor, with the lower link being displaceable by a lifting strut which acts on said lower link; which actuating device comprises a cable means which, at one end, is secured to an actuating element of the coupling hook and whose other end is guided in the direction of a driver's scat of the tractor to a fixing point and which, when subjected to tension, acts directly on the actuating element.

Such an actuating element is described in DE-2917556-Al, For actuating the two coupling hooks, there is provided a common cable which, at both ends, is suspended in the actuating elements of the coupling hooks. The central region of the cable is guided towards the driver's cab and accessible from the driver's seat. To provide the cable with definite guiding conditions, the first two portions of the cable are each guided through an eye made of wire or the like and secured at the lifting rod. To prevent excessive sagging towards the lower steering arms, stops whose diameter is greater than that of the respective eyes are secured to the two cable ends above the eyes. When the lower links and the lifting struts of such assemblies are raised, the cable ends are also raised beyond the eyes and the stops, as a result of which excessive sagging is limited. Furthermore, the cable ends are provided with reinforcements to limit the degree of sagging.

It also has to be taken into account that, when the coupling hook is in the lowered position and when the lifting strut has its maximum length, the cable is not tensioned so that the coupling hook cannot open unintentionally.

2 This means that in the raised position of the coupling hook, the cable is too long; it sags and assumes an undefined position. This may mean that it cannot be avoided that the cable gets entangled and damaged. This is the reason why the above-described cable guiding means in the form of rings, eyes or the like are attached in the region of the lifting strut. Said guiding elements result in the deflection of the cable and thus generate higher tensile forces. Almost the same applies if a chain is used as a tensioning element.

DE-OS-1457670 describes a three-point coupling having a coupling hook associated with each lower link. Each coupling hook is provided with an actuating element which is connected to a lever which extends parallel to the lower link towards the rear of the tractor. The levers of both coupling hooks are connected to one another by a transverse piece. For jointly operating the coupling hooks, there is provided a chain one end of which is suspended in a fixing point at the tractor and which, with a tension spring arranged in between, engages a tensioning element extending between the ends of the transverse piece.

It is the object of the invention to improve the guiding conditions of a cable used for actuating a coupling hook, in order to achieve a reduction in the actuating force.

In accordance with the invention, there is provided an element which generates a tensile force in one direction, which, at its first end, is secured to the tractor or to a component connected thereto, and which, by means of its second end, with a loading element connected therebet-ween, loads the cable means with a tensile force in a transverse direction, and which element, between the fixing point for the cable means near the driver's seat and the fixing means of the cable means at the actuating element, acts on the cable means and permits a return of the cable means when under tension from the position deflected by the tensile force towards the position wherein the cable means extends in a straight line.

3 The advantage of this embodiment is that, as a result of the tensile force applied transversely to the cable means, the cable means assumes a specific position. When the driver applies a force to the cable means for actuating the coupling hook, the cable means is tensioned. In a preferred embodiment, the element generating the tensile force is a tension spring. However, said element may alternatively be a weight which, around its first end, carries out a pivot movement as a result of the pivot force and which, in the process, by means of its second end, applies a force acting transversely to the cable means. While such a force is applied to the cable means, the tension spring, too, is tensioned until the cable means extends in a straight line, so that a direct tension occurs in the cable. In the embodiment according to the invention, the cable length between the fixing point at the tractor and the fixing means at the actuating element of the tractor is such that, in the non-actuated condition, the cable means assumes a defined position in which it cannot get entangled.

In a first embodiment, the tension spring is provided with an eye which constitutes the loading element for the cable means, which is formed on at the second end of said tension spring and which loosely embraces the cable means. In an alternative embodiment, there is provided a loading element in the form of a lug which loosely encloses the cable means. At its second end, the tension spring can be provided with an eye which is suspended in the lug To prevent the cable means from slipping through in the untensioned condition, it is proposed according to a further embodiment of the invention that the relative movement of the loading element towards the cable means may be limited by a stop secured to the cable means, away from the actuating element towards the fixing point at the tractor. However, the loading element is preferably movable between two stops secured to the cable means. The fixing point for the first end of the tension spring is the lifting strut acting on the lower link.

4 If necessary, the cable means may be associated with a plurality of such tension springs, in order to achieve advantageous guiding conditions.

Preferred embodiments of the invention are diagrammatically illustrated in the drawings, wherein:

Figure 1 is a diagrammatic side view of a tractor having a lower link, with the cable being in the untensioned condition; Figure 2 is a side view corresponding to Figure 1, but with the cable means being actuated manually, i.e. with a tensioned cable means; Figure 3 shows a detail regarding the design of the loading element and the guidance of same between two stops of the cable means; Figure 4 shows an alternative regarding the design of the loading element; and Figure 5 shows an assembly similar to that shown in Figure 3, but having only one stop element.

Figure 1 shows part of the tractor in outline. For the driver of the tractor 1 there is provided a driver's seat 2 which is arranged towards the rear of the tractor. The rear of the tractor 1 is provided with a three-point attaching device of which only one lower link is visible. One end of the lower link 3 is articulatably secured to the rear of the tractor. The coupling hook 6 is connected to an implement to be able to receive same. At the tractor rear 2, two such lower links 3 are arranged in parallel relative to one another. The lower link 3 is connected to a power arm 4 by means of a lifting strut 5, so that it can be pivoted around the articulation point at the tractor rear. This means that the coupling hook 6 is made to approach the ground to a greater or lesser extent or is raised therefrom. Furthermore, the lifting strut 5 also makes provision for changing the basic position, i.e. the height of the coupling hook relative to the ground can be set to meet the respective requirements. The three-point attaching dev-.-e also includes a top link which, however, is not shown. The purpose of the coupling hook 6 at the lower link 3 is to provide a 0 connection with the attachable implement or to disconnect the implement from the tractor without the driver having to leave the tractor seat 2. For actuating the coupling hook 6, there is provided an actuating element 7 which sets a bolt of the coupling hook 6. The one end of a cable means in the form of a cable 8 is secured to the actuating element 7, and the other end of the cable 8 is either secured directly at a fixing point 9 of the tractor 1 near the driver's seat 2 or it is at least held by a fixing point 9. Between the actuating element 7 and the fixing point 9, the cable 8 is associated with a tension spring 10 which, by means of a fixing eye 11, is secured to a suspension element 12 which is attached to the lifting strut. The tension spring 10 is associated with the cable 8 in the vicinity of the actuating element 7. The second end of the tension spring 10 comprises an eye 13 through which the cable 8 passes. In this way, the cable 8 is divided into two portions, i.e. the portion 8' and the portion W. Figure 1 shows that the cable 8, as a result of the effect of the spring 10, is deflected from a straight connection between the actuating element 7 and the fixing point 9.

If the cable 8 is subjected manually, by the driver, to a tensile force in the region of the fixing point 9 for the purpose of actuating the coupling hook 6, the cable 8 tightens until it extends in a straight line, as can be seen in Figure 2. Figure 2 also shows that the spring 10 is tensioned, whereas in Figure 1 it is substantially untensioned.

There are several possibilities for associating the second end of the tension spring 10 with the cable 8. It has already been explained in connection with Figures 1 and 2 that the second end of the tension spn'ne, 10 comprises an eye 13. Such an embodiment is shown in Figures 3 and 5. Figure 3 shows that the second end of the tension spring 10 loosely embraces the cable 8 by means of the eye 13 which is formed on at the second end of the tension spring. In addition there are provided stops 14, 15 on each side of the eye 13 or - if transferred to the orientation of the cable 8 according to Figures 1 and 2 - above 6 and below the eye 13. Said stops 14, 15 limit the movement of the cable 8 relative to the eye 13 and thus relative to the tension spring 10, so that the maximum and minimum length of the portion W' is delimited, as can be seen in Figures 1 and 2. In the untensioned condition, the stops 14, 15 prevent the cable Erom slipping through. Alternatively, it is possible to delimit only the maximum length of the cable portion W by providing only one stop 14, as illustrated in Figure 5.

In the embodiment according to Figure 4, the loading element is provided in the form of a lug 16. Said lug encloses the cable 8, so that an area contact occurs. The lug 16 is provided with a bore, with the spring 10, by means of an eye 13' provided at its second end, being suspended in the bore and thus loading the lug 16.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forTns thereof.

7

Claims

1. An actuating device for a coupling hook of a lower link of an implement-attachment linkage of a tractor, with the lower link being displaceable by a lifting strut which acts on said lower link; which actuating device comprises a cable means which, at one end, is secured to an actuating element of the coupling hook and whose other end is guided in the direction of a driver's seat of the tractor to a fixing point and which, when subjected to tension, acts directly on the actuating element; wherein there is provided an element which generates a tensile force in one direction, which, at its first end, is secured to the tractor or to a component connected thereto and which, by means of its second end, with a loading element connected therebetween, loads the cable means with a tensile force in a transverse direction and which element, between the fixing point for the cable means near the driver's seat and the fixing means of the cable means at the actuating element, acts on the cable means and permits a return of the cable means when under tension from the position deflected by the tensile force towards a position where the cable means extends in a straight line,

2. An actuating device according to Claim 1, wherein the element for c) generating the tensile force comprises a tension spring.

3. An actuating device according to Claim 2, wherein the tension spring is c provided with an eye which constitutes the loading element, which is formed on at the second end of said tension spring and which loosely embraces the cable means.

4. An actuating device according to Claim 2, wherein the loading element 0 is provided in the form of a lug which loosely encloses the cable means and c) 8 which is suspended in the tension spring by means of an eye formed at the second end thereof.

5. An actuating device according to any one of Claims 1 to 4, wherein the relative movement of the loading element towards the cable means is limited by a stop secured to the cable means, away from the actuating element towards the fixing point at the tractor.

6. An actuating device according to any one of Claims 1 to 4, wherein the loadinc, element is movable bet-ween two stops secured to the cable means.

0 -

7. An actuatin. device accordin- to Claim 2, wherein the tension spring is 0 0 c secured at its first end to the liftin. strut actina on the lower link..

C> 0 An actuating device substantially as hereinbefore described with c) reference to the accompanying drawings.

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6. An actuating device according to any one of Claims 1 to 4, wherein the loading element is movable between two stops secured to the cable means.

7. An actuating device according to Claim 2, wherein the tension spring is secured at its first end to the lifting strut acting on the lower link.

b

8. An actuating device substantially as hereinbefore described with reference to the accompanying drawings.

9. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.

9 Amendments to the claims have been filed as follows An actuatinc device for a coupling hook of a lower link of an 0 implement- attac hm c nt linkage of a tractor, with the lower link be' 0 1 1 in.g displaceable by a lifting strut which acts on said lower link; which actuatincy 0 0 device comprises a cable means which, at one end, is secured to an actuating element of the coupling hook and whose other end extends towards a driver's seat of the tractor to a fixing point and which, when subjected to tension, acts directly. on the actuating.element; wherein there is provided an element which generates a tensile force in one direction, which, at its first end, is secured to the tractor or to a component connected thereto and which, by means of its second end, with a loadina element connected therebetween, loads the cable means with a tensile force in a direction transverse to the cable means and which element, bet-ween the fixing point foi- the cable means near the driver's scat and the fixing means of the cable means at the actuatinc, element, acts on the cable means and permits a return of the cable means when under tension from the position deflected by the tensile force towards a position where the cable means extends in a stral-ht line.

0 2. An actuatin. device accordin. to Claim 1, wherein the element foieveneratina the tensile force comprises a tension spring 0 0 0 An actuat ne, device according to Claim 2, wherein the tension spring is with an eve which constitutes the load'ii(, element. which is formed provi 1 1 1 1 1 0 on at the second end of said tension spi-ln(..,, and which loosely, embraces the cable means.

4. An actuatin, device accord-n- to CIa'm 2, wherein the loading element the form of a lue which loosely; encloses the cable means and is provi 1 'n C which is suspended in the tension spring by means of an eye formed at the second end thereof.

5. An actuatina device according to any one of Claims 1 to 4, wherein the 0 0 relative movement of the loadina element towards the cable means is limited by c a stop secured to the cable means, away from the actuating element towards the C1 fixing point at the tractor.