AU2013206464A1 - A ratchet and pawl locking coupler for earth moving equipment - Google Patents

Abstract

A quick release coupler for earth moving equipment having a safety latch mechanism including a ratchet and pawl locking means which is deployed automatically and which must be positively deactivated by the coupler's hydraulic actuator before disengaging an implement. - 10 - If A

Description

A RATCHET AND PAWL LOCKING COUPLER FOR EARTH MOVING EQUIPMENT FIELD OF THE INVENTION: This invention relates to the earth moving, mining and construction industries, in particular but 5 not exclusively to a quick release safety coupler for earth moving equipment. The invention without limiting its scope explicitly concerns an automatic self deploying latch locking mechanism to prevent the operational, accidental or inadvertent detachment of hydraulic earth working implements. 10 BACKGROUND ART: The use of interchangeable tools or implements of earth moving equipment is known prior art. This generally involves the use of implement engaging couplers which are attached to the articulated operating arms of earth moving equipment such as back hoes, diggers, bulldozers and the like. 15 In most all cases it involves the use of couplers with hydraulic quick release latch assemblies adapted to engage universal standardised implement mount fittings. The implements or tools themselves are of significant mass and weight. Due to the rugged operational conditions and heavy wear and tear on equipment, accidental detachment of the implements can occur often 20 with disastrous consequences.. As the implements are generally of a great mass and weight there is a significant safety issue on construction sites. To alleviate the possibility of fatal accidents, various safety devices on prior art couplers have been developed. Among such safety devices are included manually inserted stop pins or locking bolts which rely on human effort and diligence for their successful implementation and operation. Furthermore, as these devices are 25 often one off workshop innovations and are often improvised to solve a particular problem, knowledge of their utilisation and implementation is often not relayed to successive operators. There is therefore a great need for inbuilt and/or automatically deployable safety mechanisms associated with such couplers. Ideally, such a device or apparatus would be automatically deployed when a coupler engages an implement and deactivated when the implement is to be 30 detached or replaced without the requirement of human intervention. In addition, as tools or implements from different manufacturers can have mounting bars of different spacing, the coupler must be adapted to accommodate these differences and deploy - 1 the safety mechanisms without significant modification or intervention. Any effort in having to manually adjust or apply safety mechanisms between implement changes which requires an operator to leave the cab of earth moving equipment, will no doubt have a high probability of non compliance and/or failure. 5 OBJECT OF THE INVENTION: It is an object of the invention to provide a novel and inventive solution to the limitations and disadvantages of the prior art. Specifically in a preferred embodiment , the invention relates to a quick release coupler for earth moving implements having a ratchet and pawl interacting 10 safety mechanism which is deployed automatically for a range of mounting bar spacing. Other aims and advantages of the invention may become apparent from the following description. 15 STATEMENT OF THE INVENTION In one aspect the invention resides in a safety coupler assembly for earth moving implements of various mounting bar distances or spacing including in combination: a frame adapted to be attached to an articulated arm of earth moving equipment; at least one of a pair of latches in pivoting connection with the frame for releasable 20 engagement with the mounting bars; an actuator to move a pivoting latch between an implement engaging and an implement disengaging position; the implement engaging position being the limit of travel of the latches on engaging the mounting bars under full extension of the actuator; ratchet and pawl locking means to lock the position of the pivoting latch; 25 wherein to couple the implement, the latches are moved by extension of the actuator to connect with the mounting bars; the locking means deploying automatically and independently, and wherein to decouple the implement, the locking means is deactivated by the retraction of the actuator before the latches are 30 disconnected from the mounting bars. Preferably, the actuator is a hydraulic actuator with a ram adapted to extend and retract in length under force of hydraulic fluid pressure. -2- Preferably, the ratchet and pawl latch locking means comprises a ratchet formed on the surface of a pivoting latch that is engaged by a pawl located on an adjacent pivot post. 5 In a preferred embodiment, the actuator pivots at one end about a captive sliding pin which is connected to a lever adapted to contact the pawl wherein retraction of the actuator causes the lever to rock the pawl on its pivot post and disengage the ratchet before any latches begin moving to the implement disengaging position. 10 Preferably, the lever additionally operates a mounting bar lock assembly via a linkage wherein extension of the actuator ram locks a mounting bar in a latch and wherein the retraction of the actuator releases the lock before the latches are moved to the implement disengaging position. Preferably, there is biasing means adapted to prevent the latches moving from the default and 15 implement engaging position to the implement disengaging position and to keep the pawl engaged with the ratchet in the absence of or low hydraulic fluid pressure or failure of the actuator. Preferably, the biasing means include torsion springs coiled around pivot posts of the pawl and 20 latches adapted to urge and retain the latches in a default implement engaging position and the pawl in contact with the ratchet wherein the torsion has to be overridden by the positive and intentional retraction of the actuator to disengage an implement. Preferably, there are projections or lugs associated with the frame adapted to function as stops 25 to limit the travel of the latches moving to the implement disengaging position or that of any other components in one or more directions. Preferably, the latches are semi-circular hook latches adapted to engage and disengage mounting bars of a cylindrical configuration. 30 BRIEF DESCRIPTION OF DRAWINGS: - 3- In order that the invention be more readily understood and put into practical effect, reference will now be made to the accompanying drawings wherein: Figure 1A and Figure 1B, show an end elevation and a cross sectional view of a preferred 5 coupler in the implement engaging position, respectively. Figure 2A and Figure 2B show a cross sectional view of the coupler in the implement disengaging position, respectively, and 10 Figure 3 shows a perspective representation of the coupler of the invention. Figure 4 shows detail of the lever. Figures 5, 5A and 5B show an alternative ratchet, pawl and lever arrangement. -4 - DETAILED DESCRIPTION OF THE INVENTION: In the interest of clarity and consistency, identical parts and components in the following drawings have been labelled with the same numbers. 5 Referring to Figure 1A and Figure 1B, there is shown a cross sectional view and end elevation of a preferred coupler 10 in the implement engaging position, respectively. The coupler's frame comprises side walls 12, 14 adapted to be attached to an articulated arm of earth moving equipment (not shown). In the example the latches 16, 18 are semi-circular hook latches 10 adapted to engage and disengage mounting bars 20, 22 of a cylindrical configuration. The actuator 24 moves pivoting latch 16 relative to fixed latch 18 between the implement engaging position as shown and the implement disengaging position ( shown by Figure 2). The ratchet and pawl latch locking means comprises a ratchet 26 formed on the surface of pivoting latch 16 that is engaged by pawl 30 located on an adjacent pivot post 32. 15 Actuator 24 pivots at one end about captive sliding pin 36 which is connected to lever 38 and wherein retraction of the ram 40 of the actuator operates the lever 38 to cause the pawl 30 to rock on its pivot post 32 away from and disengage ratchet 26 before any latches 16,18 begin moving to the implement disengaging position (as shown in Figure 2).Lever 38 additionally operates a mounting bar lock 42 associated with fixed latch 18 via a linkage 44 wherein 20 extension of the actuator ram 40 causes the mounting bar lock 42 to lock a mounting bar 20 in latch 18 and wherein the retraction of the actuator ram 40 via the linkage 44 withdraws the mounting bar lock 42 before all latches 16,18 are moved. There is biasing means in the form of torsion springs 46,48 adapted to prevent the latches 16,18 inadvertently or accidentally moving from the implement engaging to the implement disengaging position and 50 to keep pawl 30 25 engaged with ratchet 26 in the absence of or low hydraulic fluid pressure or failure of the actuator 24. Torsion springs 50, 46, 48 coiled around pivot posts 32,52,54 of pawl 30 and latches 16,18, respectively are adapted to urge and retain the latches in a default implement engaging position and the pawl 30 in contact with the ratchet 26 independently of the actuator 24 and wherein the torsion is only overridden by positive and intentional retraction of the actuator ram 30 40 on moving the latches 16,18 when disengaging implements. Preferably, there are projections or lugs (not shown) associated with the frame of the coupler adapted to function as stops to limit the travel of the latches 16,18 moving to the implement disengaging position. Latches 16,18 are semi-circular hook latches adapted to engage and disengage mounting bars 20,22 of a -5cylindrical configuration. Preferably, the coupler is also specially adapted to be connected to a swivel device or apparatus between the coupler and the articulated arm of the earth moving equipment to enable the coupler and any attached implement to swivel in a side to side motion in addition to the articulations of the arm. 5 Referring to Figure 2A and Figure 2B, there is shown a cross sectional view and end elevation of a preferred coupler 10 in the implement disengaging position, respectively. The frame of the coupler has side walls 12,14 adapted to be attached to an articulated arm of earth moving equipment (not shown). In the example the latches 16, 18 are semi-circular hook latches 10 adapted to engage and disengage mounting bars (not shown).The actuator 24 retracts pivoting latch 16 as shown to the implement disengaging position. The ratchet is released from pawl by retraction of actuator 34 pivoting about captive sliding pin 36 wherein retraction of the ram 40 of the actuator advances lever 38 to contact and push pawl 30 causing it to rock on its pivot post 32 away from and disengage ratchet 26 before latches 16,18 begin moving to the 15 implement disengaging position. Lever 38 additionally operates mounting bar lock 42 associated with latch 18 via a linkage 44 wherein the retraction of the actuator ram 40 via lever 38 and linkage 44 withdraws the mounting bar lock 42 as latches 16,18 are moved to the implement disengaging position. 20 Figure 3 shows a perspective representation of the coupler 10. The frame comprises side walls 12, 14 adapted to be attached to an articulated arm of earth moving equipment (not shown). This view shows the fixed front latch 18 and the rear pivoting latch 16 adapted to engage implement mounting bars of variable spacing (not shown). 25 Figure 4 shows detail of the lever 38 which connects through hole 38a with the captive sliding pin of the pawl (not shown) and through hole 38b with the linkages of the mounting bar lock (not shown). The lever 38 has a contact face 38c which engages the pawl or a boss of the pawl to rock the pawl away from and disengage the ratchet (not shown). 30 Figures 5, 5A and 5B show another cross sectional and perspective view of a ratchet 64, pawl 60 and lever 38. Pawl 60 is mounted in block 62 and driven against ratchet 64 by compression springs 66, 68 instead of a torsion spring arrangement. Lever 38 engages pawl 60 via contact end 38c. -6- It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth. 5 In addition, throughout the specification the terms "comprising" and "containing" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to 10 variations on the terms "comprising" and "containing" such as "comprise", "comprises", "contain" and "contains". 15 -7 -

Claims (10)

1. A safety coupler assembly for earth moving implements of various mounting bar distances or 5 spacing including in combination: a frame adapted to be attached to an articulated arm of earth moving equipment; at least one of a pair of latches in pivoting connection with the frame for releasable engagement with the mounting bars; an actuator to move a pivoting latch between an implement engaging and an implement 10 disengaging position; the implement engaging position being the limit of travel of the latches on engaging the mounting bars under full extension of the actuator; ratchet and pawl locking means to lock the position of the pivoting latch; wherein to couple the implement, the latches are moved by extension of the actuator to connect with the mounting bars; 15 the locking means deploying automatically and independently, and wherein to decouple the implement, the locking means is deactivated by the retraction of the actuator before the latches are disconnected from the mounting bars. 20

2. The coupler of Claim 1 wherein the actuator is a hydraulic actuator with a ram adapted to extend and retract in length under force of hydraulic fluid pressure.

3. The coupler of Claim 1 or Claim 2 wherein the ratchet and pawl latch locking means comprises 25 a ratchet formed on the surface of a pivoting latch that is engaged by a pawl located on an adjacent pivot post.

4. The coupler of any of the above claims wherein the actuator pivots at one end about a captive sliding pin which is connected to a lever adapted to contact the pawl wherein retraction 30 of the actuator causes the lever to rock the pawl on its pivot post and disengage the ratchet. -8-

5. The coupler of Claim 4 wherein the lever additionally operates a mounting bar lock assembly via a linkage wherein extension of the actuator locks a mounting bar in a latch and wherein the retraction of the actuator releases the lock. 5

6. The coupler of any of the above claims wherein there is biasing means adapted to urge and retain the latches in the implement engaging position as the default position and to keep the pawl engaged with the ratchet in the absence of or low hydraulic fluid pressure or failure of the actuator. 10

7. The coupler of Claim 6 wherein the biasing means comprise torsion springs coiled around pivot posts of the pawl and the latches wherein the force of the springs must be positively overridden by the intentional retraction of the actuator to disengage an implement.

8. The coupler of any of the above claims wherein the latches are semi-circular hook latches 15 adapted to engage and disengage mounting bars of a cylindrical configuration.

9. The coupler of any of the above claims wherein there are projections or lugs associated with the frame adapted to function as stops to limit the travel of the latches or any other components in one or more directions. 20

10. The coupler of any of the above claims specially adapted to be connected to a swivel device or apparatus between the coupler and the articulated arm of the earth moving equipment to enable the coupler to swivel in a side to side motion. -9-