NZ538212A - Quick hitch - Google Patents

Abstract

A hitch is provided for coupling an implement to a dipper arm of a machine. The hitch is comprised of a male component comprising a wedge portion having a pair of opposing edges with an elongate divergent face formed on each edge, a female component with opposing channel portions for receiving the edges of the male component. Each channel portion has a corresponding divergent face joining opposing inner surfaces of the channel portion whereby when coupled to the male component in a seated position, each correspondingly divergent face engages a respective divergent face of the male component with a wedge action whereby to prevent relative movement between the male and female components. A retaining means is provided to retain the male component in the seated position within the female component and to urge the male component toward the seated position. The hitch is also comprised of two connecting portions fixed to either the male component or the female component and configured for engaging opposing sides of the dipper arm. Both connecting portions have pin-receiving apertures for connecting to the dipper arm by means of a pair of transversely extending connecting pins, the longitudinal axes of the connecting pins lying in a central plane, wherein each divergent face on the component to which the connecting portions are fixed has an elongate dimension lying in a plane substantially parallel to the central plane and opposing sides of each edge are located for sliding between the opposing inner surfaces of each respective channel portion.

Description

53 8 2 Intellectual Property Office of N.Z. 1 1 FEB 2005 RECEIVED PATENTS FORM NO. 5 Fee No. 4: $250.00 ref.: 43191/24 PATENTS ACT 1953 COMPLETE SPECIFICATION QUICK HITCH We, Mark Stephen McConnell, a New Zealand citizen and Carmen Rosa McConnell, a German citizen, both of 651 Waotu Road, RD 1, Putaruru, New Zealand, 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 described in and by the following statement: 2 QUICK HITCH TECHNICAL FIELD The invention relates generally to machinery used for different tasks in construction 5 and civil engineering, and in particular to a hitch for quickly fixing an implement to such machinery.

BACKGROUND ART Machines such as hydraulically operated excavators, loaders, backhoes and the like, 10 should have the ability to utilise various implements (e.g. auxiliary tools such as buckets, breakers etc) during operation in order to complete a multitude of tasks. These machines have an articulated dipper arm on the end of which the implement is attached. The typical arrangement currently employed in the industry for connecting a machine to an implement is two parallel pins (one hinge pin and one link pin) 15 through a set of holes in the implement that can be aligned with corresponding holes in the dipper arm. The dipper arm is utilised to bear the major load of raising and lowering the implement, while an actuator is utilised to rotate the link pin about the hinge pin and hence to rotate the implement about an axis perpendicular to the dipper arm. Preferably the machine operator should be able to hitch or detach the 20 implement without leaving the cab of the machine, optionally the operator may be required to manually make and break a lock connection. The hitch should also be relatively compact, lightweight and able to take up wear in the contacting areas.

Various designs for quick hitches or couplers have been proposed, one part of which is effectively permanently connected by the hinge and link pins to the dipper arm. 25 Jaw-type quick hitches include latching jaws that releasably engage one or more mounting pins on the implement, but hitches of this type have a number of disadvantages for use in typical heavy industrial quick coupling. For example, the 3 pivoting jaw requires that the mouth of the hook be offset from the mounting two pins in order to permit rotation of the jaw for coupling an implement. This offset is further increased by the fact that the pivoting jaw must be relatively large to withstand the high bending load imposed upon it. Both of these factors tend to increase the 5 dimensions of the hitch (in particular the distance between the connection points on the dipper arm and those on the implement) and consequently to increase the loads imposed upon the hitch, its size and weight. By increasing this dimension the forces that may be applied to the implement by the dipper arm are also disadvantageously reduced, reducing for example the force that may be applied to break out a bucket 10 load. The relatively small contact area between the jaws and pins also results in high wear of these components.

US patent number 6 499 904 describes a quick hitch which uses two wedges to connect the two parts thereof, and which provides an increased contact area compared to the jaw-type hitches. One wedge is fixed to each of the two connecting 15 plates that are fixed to the dipper arm by means of the transversely extending hinge and link pins. The tapered faces of the wedges are parallel and extend outwardly and transversely, tapering between the hinge and link pins. Because of this arrangement, the maximum thickness of the wedge limits how closely the wedges may be positioned to the hinge and link pins. This geometry thus tends to disadvantageously 20 increase the distance between the connection points on the dipper arm and those on the implement. Moreover, the retaining mechanism is located on an outer side of the hitch and is thus vulnerable to damage.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference 25 constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency 4 of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed 10 components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to 15 provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a hitch for coupling an implement to a dipper arm of a machine, the hitch comprising: a male component comprising a wedge portion having a pair of opposing edges with elongate divergent faces formed on each edge; a female component with opposing channel portions for receiving the edges of the 25 male component such that, when coupled to the male component in a seated position, a correspondingly divergent face of each channel portion engages each divergent face of the male component with a wedge action whereby to prevent relative movement between the male and female components; retaining means to retain the male component in the seated position within the female component and to urge the male component toward the seated position; two connecting portions fixed to either the male component or the female component and configured for engaging opposing sides of the dipper arm, both connecting portions having pin-receiving apertures for connection to the dipper arm by means of a pair of transversely extending connecting pins, the longitudinal axes of the connecting pins lying in a central plane, wherein each divergent face on the 10 component to which the connecting portions are fixed has an elongate dimension lying in a plane substantially parallel to the central plane. it will be understood that this arrangement advantageously reduces the distance between the connection points on the dipper arm (i.e. the connecting pins) and those on the implement (i.e. the inter-engaging divergent faces on the wedge portion and 15 the corresponding faces on the female component) compared to the prior art. This reduces the loads imposed upon the hitch, its size and weight and allows higher forces to be applied to the implement by the dipper arm.

Preferably each edge of the wedge portion projects outwardly in a transverse direction from opposing sides of each connecting portion. Preferably the divergent 20 faces are substantially planar. Each divergent face preferably lies at an acute angle to an axis between the centres of the connecting pins.

Preferably the two connecting portions are two parallel plates. The connecting portions are preferably fixed to the male component. The wedge portion is preferably a plate welded to the two connecting plates, the diverging faces extending adjacent 25 to, and at an acute angle to, the connecting plates. 6 The female component preferably includes a base plate with bars releasably fixed along two opposing edges thereof, a recess being provided in an edge of the bars to form the channel portions for receiving the edges of the male component.

In a preferred embodiment the implement is a bucket. The female component may 5 be fixed to the bucket (e.g. by welding) and is preferably aligned such that when the bucket is being filled by drawing it toward the machine, the load applied to the bucket forces the male component toward the seated position. Accordingly, the alignment of the female component with respect to the bucket may vary with design of the bucket and dipper arm, but the correspondingly divergent faces are preferably 10 elongated perpendicular to a leading edge of the bucket.

The retaining means preferably includes at least one locking member mounted to one of the male and female components for extension into an aperture in the other of the male and female components to retain the male component in the seated position within the female component and to urge the male component toward the seated 15 position. Preferably the locking member or the cooperating aperture is substantially centrally positioned between the divergent faces and between the opposing ends of the diverging faces. The locking member is preferably resiliently biased to urge the male component toward the seated position.

In another aspect the invention provides a method of coupling an implement to a 20 dipper arm of a machine, including: providing a hitch as claimed in any one of the preceding claims wherein one of the male and female components is fixed by the connecting portions to the dipper arm of the machine; sliding the male component into the female component to the seated position, and 7 actuating the retaining means to retain the male component in the seated position within the female component and to urge the male component toward the seated position.

This invention provides a quick hitch which is effective and efficient in operational 5 use, it is compact and secure, may be economically constructed and has an overall simple design which minimizes manufacturing costs and maximizes performance.

BRIEF DESCRIPTION OF THE DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the 10 accompanying drawings in which: Figure 1a is a side elevation of the quick hitch of the present invention, showing the two components separated; Figure 1b is a side elevation of Fig. 1a, showing the two components connected; Figure 2 is a plan view corresponding to Fig. 1a; Figure 3 is an end elevation of the male component and locking member of the hitch of Fig. 1a; Figure 4 is a side elevation corresponding to Fig. 3; Figure 5 is a plan view of the female component and locking member of the hitch of Fig. 1a; Figure 6 is an end elevation corresponding to Fig. 5, and Figure 7 is a scrap section through the retaining mechanism of the hitch of Fig. 1a. 8 BEST MODES FOR CARRYING OUT THE INVENTION Referring to Figs 1a, 1b and 2, the quick hitch of the present invention is adapted to be mounted to the dipper arm 2 (shown in dashed outline in Fig. 1a) of a machine for releasably connecting an implement such as a bucket 1. The male component 3 is 5 pivotably fixed to the dipper arm 2 by two transversely extending connecting pins (not shown) through the parallel inner and outer apertures 6 and 7 respectively. The male component 3 includes two parallel upright connecting portions or connecting plates 8, 9 which are joined by a wedge portion or wedge plate 10 extending generally perpendicular thereto. The wedge plate 10 has a lower planar face 11 and opposing 10 edges 12,13 each projecting outwardly in a transverse direction from opposing sides of the connecting plates 8, 9.

Elongate faces 14, 15 are formed on each edge 12,13 and diverge outwardly. The longitudinal axes 50, 51 of the apertures 6, 7 and the connecting pins lie in a central plane 52 and the divergent faces 14, 15 have an elongate dimension lying in a plane 15 53 substantially parallel to the central plane P. Each divergent face 14, 15 lies at an acute angle 54 to the connecting plates 8, 9 and to an axis between the centres of the apertures 6, 7 and the connecting pins.

Bushes 21 are fixed to the connecting plates 8, 9 for supporting and fastening the pins. The male component 3 is preferably fabricated as a weldment, but may be 20 formed from one or more cast components.

The female component 4 generally comprises a socket for receiving the wedge plate 10. The female component 4 includes a base plate 19 extending between two upright divergent edge portions 21. Opposing the base plate 19 is a lip portion 20, configured so that the base plate 19 and lip portions 20 form the sides of a channel to 25 retain the wedge plate 10 therebetween for sliding movement until the divergent faces 14,15 of the wedge plate 10 seat against the correspondingly divergent faces 22 on 9 the inner side of each channel portion 17,18. The correspondingly divergent faces 22 are elongated perpendicular to a leading edge 41 of the bucket 1 and thus the load applied to the bucket when it is being filled by drawing it toward the machine, forces the wedge plate 10 toward the seated position.

Referring to Figs 3 and 4, the preferred retaining means includes a locking member 25 which projects from the wedge plate 10 into a recess in the female component 4 to retain the wedge plate 10 in the seated position within the female component 4. Two parallel upright flanges 27, 28 are fixed substantially centrally on the wedge plate 10, on the same side as the connecting plates 8, 9 and on either side of two rectangular 10 apertures 29, 30. The locking member 25 includes two tongues 31, 32 which are supported for sliding between the flanges 27, 28 to project through the apertures 29, 30, the tapered ends 26 on each tongue engaging a corresponding tapered tongue-engaging face 35 (Fig. 4) fixed to the female component 4. The locking member 25 is biased (e.g. by a spring - Fig. 6) to thereby urge the female component 4 toward 15 the seated position and taking up any wear in the contacting faces 14, 15 and 22.

The tapered ends 26 of the locking member 25 project into an opening 34 in the base portion 19 of the female component 4, shown in Fig. 4. The tongue-engaging faces 35 are provided on a replaceable plate 36 fixed to an edge of the opening 34 by a central fastener 37 and prevented from rotating by two pins 38 received in holes (not 20 shown )in the plate 36.

As shown in Fig. 6, the channels 17, 18 are formed by securing bars 40 by screw fasteners (not shown) to the edges of the base plate 19 and is itself fixed (e.g. by welding) to the bucket 1. A recess is formed in an edge of the bars 40 to define both the top portion 20 and divergent faces 22. Each divergent face 22 joins the opposing 25 inner surfaces 45, 46. Opposing sides of each edge 12, 13 are located for sliding between the inner surfaces 45, 46 of each channel 17, 18. : f " • * .

The manner of operation of the retaining means is illustrated in Fig 7 which shows locking member 25 biased downward by the compression spring 41 to bring the tapered faces 26 and 35 into contact and thus urge the wedge plate 10 into its seated position within the female component 4. The locking member 25 may be extended 5 and retracted by a screw fastener, linear actuator, or the like.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. 1.

Claims (14)

11 What we claim is:

1. A hitch for coupling an implement to a dipper arm of a machine, the hitch comprising: a male component comprising a wedge portion having a pair of opposing edges with an elongate divergent face formed on each edge; a female component with opposing channel portions for receiving the edges of the male component, each channel portion having a corresponding divergent face joining opposing inner surfaces of the channel portion whereby when coupled to the male component in a seated position, each correspondingly divergent face engages a respective divergent face of the male component with a wedge action whereby to prevent relative movement between the male and female components; retaining means to retain the male component in the seated position within the female component and to urge the male component toward the seated position; two connecting portions fixed to either the male component or the female component and configured for engaging opposing sides of the dipper arm, both connecting portions having pin-receiving apertures for connection to the dipper arm by means of a pair of transversely extending connecting pins, the longitudinal axes of the connecting pins lying in a central plane, wherein each divergent face on the component to which the connecting portions are fixed has an elongate dimension lying in a plane substantially parallel to the central plane and opposing sides of each edge are located for sliding between the opposing inner surfaces of each respective channel portion. 12

2. The hitch of claim 1 wherein each edge of the wedge portion projects outwardly in a transverse direction from opposing sides of each connecting portion.

3. The hitch of claim 1 or claim 2 wherein the divergent faces are substantially planar and diverge in their elongate direction.

4. The hitch of any one of the preceding claims wherein each divergent face lies at an acute angle to an axis between the centres of the connecting pins.

5. The hitch of any one of the preceding claims wherein the two connecting portions are two parallel plates.

6. The hitch of claim 5 wherein the wedge portion is a plate welded to the two connecting plates, the diverging faces extending adjacent to, and at an acute angle to, the connecting plates.

7. The hitch of any one of the preceding claims wherein the female component includes a base plate with bars releasably fixed along two opposing edges thereof, a recess being provided in an edge of the bars to form the channel portions for receiving the edges of the male component. 13

8. The hitch of any one of the preceding claims wherein the correspondingly divergent faces of the female component are elongated perpendicular to a leading edge of the bucket.

9. The hitch of any one of the preceding claims wherein the retaining means includes at least one locking member mounted to one of the male and female components for extension into an aperture in the other of the male and female components to retain the male component in the seated position within the female component and to urge the male component toward the seated position.

10. The hitch of any one of the preceding claims wherein the locking member or the cooperating aperture is substantially centrally positioned between the divergent faces and between the opposing ends of the diverging faces.

11. The hitch of any one of the preceding claims wherein the locking member is resiliently biased to urge the male component toward the seated position.

12. The hitch of any one of the preceding claims wherein the connecting portions are fixed to the male component. 14

13. A method of coupling an implement to a dipper arm of a machine, including: providing a hitch as claimed in any one of the preceding claims wherein one of the male and female components is fixed by the connecting portions to the dipper arm of the machine; sliding the male component into the female component to the seated position, and actuating the retaining means to retain the male component in the seated position within the female component and to urge the male component toward the seated position.

14. A hitch substantially as hereinbefore described and illustrated in the accompanying drawings. MARK STEPHEN McCONNELL and CARMEN ROSA McCONNELL JAMES & WELLS per: