IES950416A2 - A quick-release hitch - Google Patents

Abstract

A quick-release hitch for attachment to the arm of an excavator for retaining an implement provided with a pair of parallel transversely extending spaced pins 40, 50 includes a fixed reces 16 for accommodating oen of the pins 50 and a recess 35 formed in a member 18 for accommodating the other pin 40. The member 18 is rotatable in a circular recess 18 from an unlocked position (figure 1) wherein the mouth of the recess 35 faces down in alignment with the mouth of the recess 18 to allow the pin 40 to be inserted in the recess 35, to a locked position seen in figure 2. <Figure 2>

Description

Technical Field The present invention relates to a quick-release hitch for attachment to the arm of an excavator.

In the present Specification, the term excavator will be understood to have a wide meaning covering all machines, hydraulic or otherwise, utilising an implement mounted at the end of an arm, and therefore includes not only hydraulic excavators as such but also backhoes and the like.

Background Art A wide variety of implements may be used with a hydraulic excavator, for example a bucket, auger, drill, tamper, ribbing tooth, hydraulic drill, grater blade or other implement. Such implements are conventionally provided with a pair of pins extending through pin holes and the hitch of the present invention is designed to co-operate with these pins without requiring any permanent modifications.

A number of hitches are known in the prior art; however, these have a number of disadvantages including being both complex to manufacture and operate and somewhat dangerous in the event of a hydraulic failure.

Disclosure of the Invention According to the present invention there is provided a quick-release hitch for attachment to the arm of an excavator for retaining an implement provided with a pair of parallel transversely extending spaced pins, the hitch comprising a fixed recess having an open mouth for accommodating one of the pins and a hydraulically powered securing means for releasably securing the other pin.

OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 JNL. No....n??55........OF.^.r.2-2Brief Description of the Drawings An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevation in partial cross-section of a hitch according to the invention in an unlocked position; Figure 2 is a view of the hitch of Figure 1 in a locked position; and Figure 3 is a front view of the hitch of Figure 1.

Description of Preferred Embodiment Referring now to the drawings wherein similar numerals have been used to indicate like parts, a quick-release hitch generally indicated at 10 comprises a pair of laterally spaced upper flanges 11 interconnected by means of a laterally extending member 12 welded thereto. A pair of laterally spaced lower flanges 13 are welded to the undersides of the upper flanges 11.

Each upper flange 11 has a forward hole 14 and a rear hole 15 each for receiving a respective pin so as to connect the hitch 10 to an excavator arm (not shown) as is known in the art. Each lower flange 13 is provided with a fixed front hook in the form of a forwardly-facing *U' shaped recess 16. The recess 16 is intended for accommodating one of the two parallel transverse pins 50 on, for example, a bucket (not shown).

A hydraulically operable securing means comprises a pair of laterally spaced hook members 18 (only one shown) with respective U-shaped recesses 35. The members 18 are attached to the operating arm 19 of a double acting hydraulic ram 20 by a respective bracket 21. The hydraulic ram 20 is mounted to a bracket 22 fixed relative to the fixed hooks 16. The hydraulic ram 20 is controlled by hydraulic fluid provided via pipes 23 connected to the hydraulic system of, for example, an excavator (not shown).

As shown in Figures 1 and 2, each hook member 18 is rotatably mounted -3within a generally circular recess 24 in a housing 25 which substantially encloses the space between the flanges 13. Each recess 24 has a downwardly-facing opening or mouth 26 at the lower end 27 for receiving the other pin 40 of, for example, the bucket or other implement.

The operation of the quick-release hitch 10 is as follows. First the hitch 10 is fitted to an excavator arm by means of pins which engage in holes 14, 15 in conventional manner, and the pipes 23 of the hydraulic ram 23 are then connected to the hydraulic system of the excavator. Now an implement is fitted to the hitch 10 in the following manner, the implement being fitted with pins 40, 50 on its hanger arm.

First the forwardly facing recesses 16 are engaged around one of the implement pins 50 by suitably maneuvering the excavator arm generally in a sideways direction. Then, with the member 18 in an unlocked position, i.e. with the mouth of the recess 35 in the member 18 facing downwardly substantially in alignment with the mouth 26 in the circular recess 24, the member 18 is engaged over the other implement pin 40 by lowering the hitch. The hydraulic ram 20 is now actuated and as the operating arm 19 is retracted into the hydraulic ram 20 the member 18 is caused to rotate through about 90 degrees until it moves to the position shown in Figure 2 wherein the mouth of the recess 35 is closed by the wall of the circular recess 24 so that the implement pin 40 is now locked in the recess 35. The implement is now securely connected to the end of the excavator arm.

It will be appreciated that even if the hydraulic system should fail, for example by an hydraulic leak or for another reason, this particular construction is extremely safe. The main reason is that, referring to Figures 1 and 2, the weight of the bucket or other implement is carried by the pins 40, 50 and the force which this exerts on the hook member 18 is downwards. As the hook member 18 in its locked position in Figure 2 has an arm 30 which extends across the opening 26 and any downward force acting on this arm tends to urge the arm 30 against the lower wall parts 31 of the circular recess 24. Thus, there is no tendency for the hook member 18 to rotate to the position of Figure 1 and thus to free the pin 40. This is highly advantageous from a safety point of view and would allow an 9^0416 -4excavator operator to take appropriate action in the event of a hydraulic failure before the bucket would free itself from the hitch 10. 950416.

Claims (5)

1. A quick-release hitch for attachment to the arm of an excavator for retaining an implement provided with a pair of parallel transversely extending spaced pins, the hitch comprising a fixed recess having an open mouth for accommodating one of the pins and a hydraulically powered securing means for releasably securing the other pin.

2. A quick-release hitch as claimed in claim 1, wherein the securing means comprises a member having a further recess for accommodating the other pin, the member being mounted in a support means for movement between a first position wherein the mouth of the recess is open for reception of a pin and a second position wherein the mouth of the recess is closed to lock a pin in the recess.

3. A quick-release hitch as claimed in claim 2, wherein the said member is rotatably mounted in a generally circular recess for rotation between the said first position wherein the mouth of the further recess is substantially aligned with the mouth of the circular recess and the said second position wherein the mouth of the further recess is rotated out of alignment with the mouth of the circular recess.

4. A quick-release hitch as claimed in claim 3, wherein the fixed recess and the circular recess face in respective directions approximately 90 degrees apart such that the hitch can be maneuvered generally sideways into engagement with one pin and then lowered downwardly onto the other pin.

5. A quick-release hitch as claimed in claim 2, 3 or 4, wherein the said member is movable by a double acting hydraulic ram.