Coupling apparatus

Abstract

A coupling apparatus 1 for coupling an attachment to a dipper arm of a machine. The apparatus includes a coupler body 7, a first fixed engaging means 11 mounted on the coupler body for engaging a firs

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. The fixed engaging member usually includes a latch or other blocking member associated with it to retain the coupling pin m position, and the movable engaging member is usually hydraulically operated. When removing the accessory from the coupler, usually, the movable engaging member moves to disengage from the associated second coupling pin first, leaving the accessory essentially hanging from the fixed engaging member via the first coupling pin. At this point, any latch member associated with the fixed engaging member will have been moved to an unlatched position, leaving the accessory freely hanging. There is a risk associated with this in that as the dipper arm and / or coupler are angled to permit full removal of the first coupling pin, and hence the accessory, from the fixed engaging member, it could simply drop or otherwise suddenly fall from the fixed engaging member, which poses a serious risk to the safety of personnel nearby, and could cause damage to a surface on which it falls. There is therefore a need to provide a coupling apparatus which has improved safety features which prevents or substantially reduces the possibility of accidental or inadvertent release of accessories from the coupler. 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 first, fixed engaging means having an opening to receive the first coupling pin, in use, and a seat, located at a rearward point of the fixed engaging means at an opposing end from said opening; characterized in that said first, fixed engaging means further includes a recessed portion located between the seat, and a lip of the engaging means defining a distal end and / or opening thereof. Typically, said second, movable engaging means is movable between an engaged position wherein it engages the second coupling pin as the first, fixed engaging means engages the first coupling pin, in use, and a disengaged position. Preferably, the first, fixed engaging means is provided in the form of a front, fixed jaw. Typically, said fixed jaw has a jaw opening located at a front end, and a jaw seat located at an opposing rear end, arranged to receive the first coupling pin, in use. In one embodiment, the seat of the first, fixed engaging means is provided to be duabradiused, thereby permitting couplings pins of various diameters to sit therein, in use. Typically, the first, fixed engaging means includes an intermediate portion, located between the seat and the recessed portion. Preferably, said intermediate portion comprises a substantially flat interior surface. In some embodiments, said intermediate portion extends at least a length equal to a diameter of the first coupling pin received therein, in use. Preferably, the recessed portion has a profile shaped to match and / or complement an outer profile of the first coupling pin, in use. In one embodiment, the lip extends to a distal end of the first, fixed engaging means to a point substantially in line with the surface of the intermediate portion. Typically, the first, fixed engaging means does not narrow in width at the opening, that is to say, preferably, the distance between the lip of the first, fixed engaging means and a lower face of the coupler body which defines the opening, is at least equal to the distance between the interior surface of the intermediate portion and the lower face of the coupler body. Preferably, the coupling apparatus further includes a latch member associated with and pivotable with respect to the first, fixed engaging means between latched and unlatched positions. Typically, said latch member is biased to the latched position by biasing means. In one embodiment, said biasing means are provided as one or more torsion spring members. In one embodiment, said latch member is movable to the unlatched position upon movement of the second, movable engaging means to a disengaged position. In one embodiment, said second, movable engaging means includes an elongate finger portion, extending along the coupler body away from and engaging portion of the movable engaging means and towards the first, fixed engaging means. Typically, movement of the second, movable engaging means towards the first, fixed engaging means moves is to the disengaged position. Preferably, as the second, movable engaging means is moved to the disengaged position, the finger portion engages the latch member and urges it into the unlatched position, in use. Typically, the recessed portion acts, in use, to retain the first coupling pin within the first, fixed engaging means after a latch member of the first, fixed engaging means is moved to an unlatched position and the second, movable engaging means has been moved to a disengaged position, thereby releasing the second coupling pin. In one embodiment, said recessed portion is located in the first, fixed engaging means in a position which is forward of the latch member. That is to say, the recessed portion is located on the open-end side of the engaging means, with respect to the latch member, thus, if the latch member inadvertently moves to the latched position, the coupling pm, when resting in the recessed portion, is not trapped within the first, fixed engaging means. The present invention therefore has the advantage that the provision of the recessed portion in the first, fixed engaging means, or a front jaw of the coupling apparatus, allows the coupling pin to pivot therein while being safely removed, and without being prematurely and / or suddenly ejected therefrom. In one embodiment, the coupling apparatus is provided to be hydraulically operable. Typically, drive means are provided to affect movement of the movable engaging means. Preferably, said drive means are hydraulically operated. Embodiments of the present invention will now be described with reference to the accompanying figures, wherein: Figure 1 illustrates a side-on view of a coupling apparatus, in accordance with an embodiment of the present invention; Figures 2a-b illustrate side-on cross-sectional views of a coupling apparatus, in engaged and disengaged arrangements respectively, according to an embodiment of the present invention; Figure 3 illustrates a side-on view of a coupler body of a coupling apparatus, in accordance with an embodiment of the present invention; and Figures 4a-c illustrate step-by-step stages of a process to detach an accessory from a coupling apparatus and dipper arm, in accordance with an embodiment of the present invention. Referring now to the figures and firstly to Figure 1, 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 front jaw 11. The front 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 rear sliding jaw 15. The sliding jaw 15 is shown in more detail in Figures 2a-b, and includes a body portion 17 located and linearly movable in the coupler body 7. The jaw 15 extends down from the body 17 and is arranged to engage a second coupling pm 19 of the accessory 3, in use. The rear jaw 15 is slidably movable between a disengaged position, wherein it is moved to substantially abut a rear side of the front jaw 11, and an engaged position, wherein it is moved rearwardly along the coupler body 7 to a position spaced apart from the fixed front jaw 11. The engaged position is illustrated in Figure 2a and the disengaged position is illustrated m Figure 2b. The front jaw 11 includes a jaw opening 21 through which the first coupling pin 13 is received, and a jaw seat 23 located at a rearward point of the jaw 11 at an opposing end from the opening 21. When fully engaged, the first coupling pin 13 locates within the jaw seat 23 of the front jaw 11. The front jaw 11 further includes a recessed portion 25, which is located between the jaw seat 23 and a lip 27 of the jaw 11, the lip 27 defining the opening 21 of the jaw 11 at a distal end thereof. The recessed portion 25 is provided such that as the coupler 1 is moved into the disengaged position and the second coupling pin 19 is released from the sliding jaw 15, the first coupling pin 13 moves form the jaw seat 23 towards the opening 21, but is caught and at least temporarily retained in the recess 25. This prevents the pm 13 from freely and / or suddenly sliding fully out of the front jaw 11 and falling in an uncontrolled manner to the surface below, which could otherwise result in serious injury to personnel or cause damage to surrounding equipment. Instead, with the pin 13 retained in the recess 25, the accessory simply hangs in place and pivots about the pm / recess, allowing personnel to lower and release the accessory 3 in a controlled and safe manner. In some further embodiments of the invention, the jaw seat 23 is formed to be dual-radiused. That is to say, it is formed so as to be able to accommodate coupling pins of varying diameters. For example, the rearward-most point of the seat 23 is arranged to accommodate smaller pin diameters, and may be formed to have a radius of approximately 22.65mm, thereby accommodating pins having a 45mm diameter. A more forward point of the seat 23 may be formed to have a radius of approximately 25.15mm, thereby accommodating pins having up to a 50mm diameter. The front jaw 11 may further include an intermediate portion in the form of an extended, substantially flat interior surface 28. The intermediate portion 28 is located between the jaw seat 23 and the recessed portion 25, and forms a surface along which the first coupling pin 13 may travel as it locates with and moves away from the jaw seat 23. In some embodiments, the surface of the intermediate portion 28 extends a length at least equal to the diameter of the first coupling pin 13. In some embodiments, the surface 28 would extend a length at least equal to the radius of the first coupling pin 13. The recessed portion 25 itself is formed having a profile shaped to match and / or complement the outer profile of the first coupling pin 13. Typically, the profile is formed such that the arc created has a radius substantially equal to the larger radius provided for in the jaw seat 23, in order to be able to accommodate coupling pins of the larger diameter. Typically, the lip 27 extends to a distal end 31 of the jaw 11 to a point substantially in line with the surface of the intermediate portion 28, such that the jaw 11 is formed so as not to narrow in width at the opening 21. That is to say, preferably, the distance between the lip 27 and the lower face 9 of the coupler body 7 which defines the opening 21, is at least equal to the distance between the interior surface of the intermediate portion 28 and the lower face 9 of the coupler body 7. In order to retain the first coupling pin 13 within the front jaw 11 when engaged, the front jaw 11 further includes a latch 29 provided therewith. The latch 29 is pivotable in the front jaw 11 and thus movable between a latched position, shown in Figure 2a, wherein a distal end 31 extends down from the lower face 9 of the coupler body 7 and into the front jaw 11, and an unlatched position, shown in Figure 2b, wherein the latch 29 pivots such that it locates fully or almost fully within the coupler body 7. In the latched position, the distal end 31 of the latch 29 closes off the opening 21 by creating a substantially reduced gap between itself and the interior surface of the jaw 11, as compared with the interior surface of the jaw 11 and the lower face 9 of the coupler body 7, thereby preventing inadvertent removal of the first coupling pin 13 from the jaw 11. The latch 29 is pivotable about a pivot point 33 located within the coupler body 7, and biasing means in the form of one or more spring members 35 are provided to bias the latch 29 to the latched position. The latch 29 is movable to the unlatched position upon movement of the rear sliding jaw 15 form the engaged position to the disengaged position, shown in Figure 2b. The body portion 17 of the rear sliding jaw 15 includes an elongate portion in the form of a finger 37, which extends along the coupler body 7 and away from the opening of the jaw 15, towards the front jaw 11. As the rear, sliding jaw 15 moves from the engaged position towards the disengaged position, and thus towards the fixed front jaw 11, the finger 37 contacts a body portion 39 at a proximal end of the latch 29, located on the opposite side of the pivot point 33 from the distal end 31. Continued movement of the sliding jaw 15, and thus the finger 37 towards the front jaw 11 causes the latch 29 to be pivoted from the latched position, against the biasing force of the springs 35, to the unlatched position, thereby enabling the coupling pin 13 located on the jaw seat 23 to move therefrom and towards the recessed portion 25. The coupler 1, and in particular the rear sliding jaw 15 is provided to be hydraulically operable, and drive means in the form of one or more pistons 41 are provided to actuate the sliding, linear movement of the rear j aw 15. The subsequent stages of detachment of the accessory 3 form the coupler 1 are shown in Figures 4a-c. Once the coupler 1 is in the disengaged position, and the second coupling pm 19 has been released from the rear sliding jaw 15, the recessed portion 25 acts to retain the first coupling pin 13 in position within the front jaw 11. This enables the accessory 3 to be able to hang freely from the front jaw 11 as the dipper arm 5 gradually lowers it to the ground (Figure 4b) and subsequently released (Figure 4c). this action can be carried out in a safe and controlled manner thereby removing the risk of the accessory 3 falling out of the jaw 11 and from the coupler 1, potentially causing injury or damage to surrounding personnel or equipment. A further feature of the recessed portion 25 is that it is located in a position in the front jaw 11 which is forward of the latch 29. That is to say it is located closer to the opening 21 of the jaw 11 than the latch 29. Consequently, if the latch 29 were to inadvertently move to the latched position, for example due to failure of the hydraulic drive means 41, the coupling pin 13 would remain resting in the recessed portion 25 still able to be released therefrom, and not be trapped within the jaw 11. The present invention therefore provides an improved coupler 1, which has an additional safety feature preventing inadvertent release of the first coupling pin 13 and thus the accessory 3, potentially causing serious accident. The provision of the recessed portion 25 and its positioning within the front, fixed jaw 11, ensures that as the coupler 1 is moved to a disengaged position and the second coupling pin 19 is released from the rear, sliding jaw 15, the first coupling pin 13 may move from the jaw seat 23 but does not simply fall out form the front jaw 11; rather, it is retained in the recess for a controlled release by the dipper arm 5, and is also not in danger of being trapped within the front jaw 11 should there be a failure of the hydraulics 41 resulting in inadvertent movement of the latch 29 to the latched position.

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 first, fixed engaging means having an opening to receive the first coupling pin, in use, and a seat, located at a rearward point of the fixed engaging means at an opposing end from said opening;characterized in that said first, fixed engaging means further includes a recessed portion located between the seat, and a lip of the engaging means defining a distal end and / or opening thereof.

2. A coupling apparatus according to claim 1, wherein said second, movable engaging means is movable between an engaged position wherein it engages the second coupling pin as the first, fixed engaging means engages the first coupling pin, in use, and a disengaged position.

3. A coupling apparatus according to claim 1, wherein the first, fixed engaging means is provided in the form of a front, fixed jaw.

4. A coupling apparatus according to claim 3, wherein said fixed jaw has a jaw opening located at a front end, and a jaw seat located at an opposing rear end, arranged to receive the first coupling pin, in use.

5. A coupling apparatus according to claim 4, wherein the seat of the first, fixed engaging means is provided to be dual-radiused, thereby permitting coupling pins of various diameters to sit therein, m use.

6. A coupling apparatus according to claim 1, wherein the first, fixed engaging means includes an intermediate portion, located between the seat and the recessed portion.

7. A coupling apparatus according to claim 6, wherein said intermediate portion comprises a substantially flat interior surface.

8. A coupling apparatus according to claim 6, wherein said intermediate portion extends at least a length equal to a diameter of the first coupling pin received therein, in use.

9. A coupling apparatus according to claim 1, wherein the recessed portion has a profile shaped to match and / or complement an outer profile of the first coupling pin, in use.

10. A coupling apparatus according to claim 1, wherein the lip extends to a distal end of the first, fixed engaging means to a point substantially in line with the surface of the intermediate portion.

11. A coupling apparatus according to claim 6, wherein the first, fixed engaging means does not narrow in width at the opening, that is to say, the distance between the lip of the first, fixed engaging means and a lower face of the coupler body which defines the opening, is at least equal to the distance between the interior surface of the intermediate portion and the lower face of the coupler body.

12. A coupling apparatus according to claim 1, wherein the coupling apparatus further includes a latch member associated with and pivotable with respect to the first, fixed engaging means between latched and unlatched positions.

13. A coupling apparatus according to claim 12, wherein said latch member is biased to the latched position by biasing means.

14. A coupling apparatus according to claim 13, wherein said biasing means are provided as one or more torsion spring members.

15. A coupling apparatus according to claim 1, wherein said latch member is movable to the unlatched position upon movement of the second, movable engaging means to a disengaged position.

16. A coupling apparatus according to claim 1, wherein said second, movable engaging means includes an elongate finger portion, extending along the coupler body away from an engaging portion of the movable engaging means and towards the first, fixed engaging means.

17. A coupling apparatus according to claim 1, wherein movement of the second, movable engaging means towards the first, fixed engaging means moves is to the disengaged position.

18. A coupling apparatus according to claim 17, wherein as the second, movable engaging means is moved to the disengaged position, the finger portion engages the latch member and urges it into the unlatched position, in use.

19. A coupling apparatus according to claim 1, wherein the recessed portion acts, in use, to retain the first coupling pin within the first, fixed engaging means after a latch member of the first, fixed engaging means is moved to an unlatched position and the second, movable engaging means has been moved to a disengaged position, thereby releasing the second coupling pin.

20. A coupling apparatus according to claim 12, wherein said recessed portion is located in the first, fixed engaging means in a position which is forward of the latch member.

21. A coupling apparatus according to claim 1, wherein the coupling apparatus is provided to be hydraulically operable.

22. A coupling apparatus according to claim 1, wherein drive means are provided to affect movement of the movable engaging means.

23. A coupling apparatus according to claim 22, wherein said drive means are hydraulically operated.

Images