Coupling apparatus

Abstract

A coupling apparatus for coupling an attachment to a dipper arm. The apparatus includes a coupler body 7; a fixed engaging means 11 mounted on the coupler body for engaging a first coupling pin of the

Description

The invention to which this application relates is a coupling apparatus. Coupling apparatus for use in attaching a dipper arm of an excavator to various accessories are well known. The couplers are used to attach buckets of various sizes, or other construction implements, to the dipper arm for subsequent use. The couplers are usually provided to be detachably attachable to both the dipper arm and the accessory which is to be used. Usually, the coupler remains on the dipper arm and the various accessories are attached, detached, interchanged as required. The attachment between the coupler and the accessory typically involves the provision of a pair or parallel coupling pins fixed on the accessory, which then connect or otherwise engage with respective engaging members on the coupler. In most common configurations, a pair of engaging members is provided on the coupler, one of which is fixed in place with the other being movable. The fixed engaging member usually contacts one of the coupling pins first, in an engaging position, and subsequently the second engaging member will then move into position engaging the second coupling pin and securing the accessory to the coupler. Couplers can be hydraulically operated or manually operated. In manually operated couplers, the movable engaging member is often biased to a closed position and is required to be moved manually to an open position to allow the coupling pin to access the opening and then be retained in place. The movable engaging member is normally biased to a closed position via a die spring or similar such member provided to the rear of the member, and a user essentially moves the member against the biasing force of the spring to create an opening for the coupler pin to engage. The die spring is usually held in placed via the provision of a pair of spigots being formed at opposing ends: one on the rear of the moveable member; and another formed in the body of the coupler, and in which the ends of the die spring rest. However, problems arise in that the spring may not be fully supported by the spigots, and they may inadvertently pop out under pressure, which is of course undesirable and could present a safety hazard. To address this, manufacturers may provide a rod in the coupler body, around which the die spring locates. The rod is pivotably fixed to the rear of the movable member, and as the member is moved to the open position, the spring is compressed and the rod extends further into the body of the coupler. However, this too has inherent problems as it requires the size of the coupler body to be extended in order to accommodate the rod as it moves through the body. The increased size of the coupler body increases the cost of manufacture and also the overall weight, consequently limiting the amount of load the accessory attached to the coupler can accommodate. Further, support pins which may be provided to retain the rod can be placed under increasing pressure as the spring compresses, leading to breakages. There is therefore a need to provide a coupling apparatus which addresses these issues while providing a cost and weight efficient coupler body. It is therefore an aim of the present invention to provide an improved coupling apparatus which overcomes the aforementioned problems associated with the prior art. According to a first aspect of the invention there is provided a coupling apparatus for coupling an attachment to a dipper arm of a machine, the apparatus including: a coupler body; a first, fixed engaging means mounted on the coupler body for engaging a first coupling pin of the attachment, in use; a second, movable engaging means mounted on the coupler body for engaging a second coupling pin of the attachment, in use; the second, movable engaging means being movable between open and closed configurations, and biased to the closed configuration by biasing means, said biasing means comprising a die spring member located around an elongate rod member, characterized in that the movable engaging means comprises a channel located therethrough from a rearward side to a forward side; and said rod member is provided to be fixed within the coupler body at a first end thereof, and a second end thereof extends towards the rearward side of the movable engaging means, and wherein when the movable engaging means is moved to the open configuration, the second end of the rod member extends through the channel thereof. Typically, said movable engaging means is provided to be pivotable about a pivot point, between the open and closed configurations. In one embodiment, said channel is tapered to allow for pivoting movement of the movable engaging means and to permit the rod member to extend therethrough as the movable engaging means is moved to the open configuration. In one embodiment, when the movable engaging means is in the closed configuration, the second end of the rod member may extend at least partially into the channel. Typically, the first end of the rod member comprises a head portion having a channel extending therethrough. Further typically, the channel in the head portion is arranged to be perpendicular to a longitudinal axis of the rod member, and parallel to longitudinal axes of the first and second coupling pins, when attached to the coupling apparatus. Preferably, a support pin member is provided, extending through the channel of the head portion. Typically, said support pin member is fixed at first and second opposing ends thereof within the coupler body. Typically, the first and second ends of said support pin member rest in seats provided on opposing sides of the coupler body. Preferably, said die spring member is located around the rod member and a first end of the die spring member abuts against a head portion of the rod member. Typically, a second end of the die spring member abuts against abutment means provided associated with said movable engaging means. In one embodiment, said abutments means may be provided as a pin member having first and second opposing ends located in the movable engaging means, and extending across the channel thereof. Typically, the first and second ends of the abutment pin member rest in seats provided on opposing sides of the movable engaging means. Preferably, the abutment pin member has a centrally located aperture formed therethrough, and through which the second end of the rod member may extend. Typically, the abutment pin member may be rotatable about a longitudinal axis thereof as the movable engaging means moves between the open and closed configurations, in use. The present invention thus provides an improved coupling apparatus, wherein the rod member around which the die spring locates, remains fixed in position and more securely supported in the coupler body by the support pin. By ensuring the rod member remains fixed in position, this means the height and thus weight of the coupling apparatus can be kept compact and to a minimum, thereby reducing costs and increasing load capabilities. Forming a channel in the movable engaging means enables the orientation of the rod member effectively to be reversed, allowing it to be fixed in position and its second end does not encroach on the receiving area for the second coupling pin once the movable engaging means has been moved to the open configuration. Embodiments of the present invention will now be described with reference to the accompanying figures, wherein: Figure 1 illustrates a cross-sectional view of a coupling apparatus in accordance with an embodiment of the present invention; Figure 2 illustrates a cross-sectional view of a coupling apparatus attached to a dipper arm and engaging coupling pins of an attachment, in accordance with an embodiment of the present invention; Figure 3 illustrates a cut-away view of a coupling apparatus along line A-A of Figure 1, in accordance with an embodiment of the present invention; and Figure 4 illustrates a reverse view of the interior of a coupling apparatus in accordance with an embodiment of the present invention. Referring now to the figures and firstly to Figures 1 and 2, there is shown a quick hitch coupler 1 provided for attaching an accessory, excavator bucket 3 or the like to a dipper arm 5 of an excavator. The coupler 1 comprises a coupler body 7, having a lower face 9, down from which extends a first, fixed engaging member in the form of a fixed jaw 11. The fixed jaw 11 is arranged to receive and engage a first coupling pin 13 of the accessory 3, in use. The coupler 1 further includes a second, movable engaging member in the form of a pivoting jaw 15. The pivoting jaw 15 is pivotably movable between open and closed configurations and when in the open configuration the coupler 1 is arranged to receive a second coupling pin 17 of the accessory 3 in the jaw opening 19. The pivoting jaw 15 is biased to the closed configuration via the provision of biasing means, provided in the form of a die spring 21 which is located around an elongate rod 23. The rod 23 has a first end 25 which is fixed in position in the coupler body 7 and a second, opposing end 27 which extends towards the pivoting jaw 15. The pivoting jaw 15 further includes a channel 29 located therethrough from a rearward side to a forward side, allowing the second end 27 of the rod 23 to extend into the channel 29. As the pivoting jaw 15 is moved from the closed configuration to the open configuration in the direction of Arrow B and via a pivoting movement about pivot point 31, the second end 27 of the rod 23 extends further through the channel and thus the pivoting jaw 15. In order to receive the second end 27 of the rod 23 as the jaw 15 is pivoting to the open configuration, the channel 29 is formed to be tapered or funnelled; this is best shown when the jaw 15 is in the closed configuration in Figure 1, and then in the open configuration in Figure 2. As referred to above, the rod 23 is fixed in the coupler body 7 at a first end 25 thereof. In preferred embodiments of the invention, the first end 25 comprises a head portion of the rod 23. The head portion serves two main functions. Firstly, a channel or aperture is formed therethrough in a direction perpendicular to the longitudinal axis of the rod 23 and parallel with the longitudinal axes of the coupling pins 13, 17 of the accessory 3, when attached to the coupler 1. A support pin 33 is located through the aperture of the head portion and is fixed at first and second opposing ends thereof within the coupler body 7. The fixings may be provided in the form of seats, recesses or other such receiving portions for the pin 33. The second function of the head portion at the first end 25 of the rod 23 is to act as an abutment face for a first end of the die spring 21. A second end of the die spring 21 is provided to abut against abutment means in the form of an abutment pin 35 located with the pivoting jaw 15. The abutment pin 35 is located receiving portions in the form of seats, recesses or the like at first and second opposing ends thereof within the body of the pivoting jaw 15 and it extends across the channel 29 of the jaw 15. The pin 35 further includes a centrally located aperture formed therethrough, and through which the second end 27 of the rod 23 may extend. Consequently, as the pivoting jaw 15 is moved to the open configuration, the abutment pin 35 serves to compress the die spring 21 against the abutment face of the head portion at the opposing end 25 of the rod 23. As the jaw 15 moves, the rod 23 itself remains substantially fixed in position and the aperture of the abutment pin 35 slides along the rod 23 such that the end 27 of the rod 23 extends into the channel 29. Just as the channel 29 is tapered or funnelled to accommodate the rod 23 through the pivoting movement of the jaw 15, the pin 35 is provided to be free to rotate in its fixings through the same pivoting movement of the jaw 15. Consequently, the present invention provides a novel and improved coupler 1, which has essentially reversed the orientation of the rod 23, allowing it to remain substantially fixed in position and more securely supported in the coupler body 7 by the support pin 33. This means the height and weight of the coupler 1 can be kept compact and to a minimum, thereby reducing costs and increasing load capabilities. The channel 29 in the pivoting jaw 15 enables the jaw to operate and move as before, without being hindered by the presence of the rod 23, which itself does not encroach on the receiving area or jaw opening 19 for the second coupling pin 17 once in the open configuration. Furthermore, the abutment pin 35 is reduced in length when compared to pins used in previous models located in the coupler body (in examples where the rod moves with the moving jaw). This ensures that the unsupported length of the pin 35 is shorter and thus the structural integrity of the pin 35 as the die spring 21 abuts against it, under increasing pressure when moving to the open configuration, is greatly improved.

Claims

1. A coupling apparatus for coupling an attachment to a dipper arm of a machine, the apparatus including:a coupler body;a first, fixed engaging means mounted on the coupler body for engaging a first coupling pin of the attachment, in use;a second, movable engaging means mounted on the coupler body for engaging a second coupling pin of the attachment, in use;the second, movable engaging means being movable between open and closed configurations, and biased to the closed configuration by biasing means, said biasing means comprising a die spring member located around an elongate rod member,characterized in that the movable engaging means comprises a channel located therethrough from a rearward side to a forward side; andsaid rod member is provided to be fixed within the coupler body at a first end thereof, and a second end thereof extends towards the rearward side of the movable engaging means,and wherein when the movable engaging means is moved to the open configuration, the second end of the rod member extends through the channel thereof.

2. A coupling apparatus according to claim 1, wherein said movable engaging means is provided to be pivotable about a pivot point, between the open and closed configurations.

3. A coupling apparatus according to claim 1, wherein said channel is tapered to allow for pivoting movement of the movable engaging means and to permit the rod member to extend therethrough as the movable engaging means is moved to the open configuration.

4. A coupling apparatus according to claim 1, wherein when the movable engaging means is in the closed configuration, the second end of the rod member extends at least partially into the channel.

5. A coupling apparatus according to claim 1, wherein the first end of the rod member comprises a head portion having a channel extending therethrough.

6. A coupling apparatus according to claim 5, wherein the channel in the head portion is arranged to be perpendicular to a longitudinal axis of the rod member, and parallel to longitudinal axes of the first and second coupling pins, when attached to the coupling apparatus.

7. A coupling apparatus according to claim 6, wherein a support pin member is provided, extending through the channel of the head portion.

8. A coupling apparatus according to claim 7, wherein said support pin member is fixed at first and second opposing ends thereof within the coupler body.

9. A coupling apparatus according to claim 8, wherein the first and second ends of said support pin member rest in seats provided on opposing sides of the coupler body.

10. A coupling apparatus according to claim 1, wherein said die spring member is located around the rod member and a first end of the die spring member abuts against a head portion of the rod member.

11. A coupling apparatus according to claim 10, wherein a second end of the die spring member abuts against abutment means provided associated with said movable engaging means.

12. A coupling apparatus according to claim 11, wherein said abutment means are provided as a pin member having first and second opposing ends located in the movable engaging means, and extending across the channel thereof.

13. A coupling apparatus according to claim 12, wherein the first and second ends of the abutment pin member rest in seats provided on opposing sides of the movable engaging means.

14. A coupling apparatus according to claim 12, wherein the abutment pin member has a centrally located aperture formed therethrough, and through which the second end of the rod member extends.

15. A coupling apparatus according to claim 14, wherein the abutment pin member is rotatable about a longitudinal axis thereof as the movable engaging means moves between the open and closed configurations, in use.A

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