AU2013211448A1 - A safety coupler for earth moving equipment using an internal locking actuator - Google Patents

Abstract

A safety coupler assembly for earth moving implements using a fluid actuator having an internal safety locking mechanism including inter alia cooperative locking means between the actuator's 5 piston and the actuator's cylinder adapted to lock and unlock the piston in an extended and retracted position. - 10 -

Description

A SAFETY COUPLER FOR EARTH MOVING EQUIPMENT USING AN INTERNAL LOCKING ACTUATOR FIELD OF THE INVENTION: 5 This invention relates to the earth moving, mining and construction industries, in particular but not exclusively to a quick release coupler using a safety locking actuator for earth moving equipment. The invention without limiting its scope concerns prevention of 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 with a hydraulic actuator having an internal 10 safety mechanism. Other aims and advantages of the invention may become apparent from the following description. STATEMENT OF THE INVENTION In one aspect, the invention resides in a safety coupler assembly for earth moving implements 15 having an internally locking actuator for 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 engagement with the mounting bars; 20 an actuator to move a pivoting latch between an implement engaging position 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; the actuator having an actuator piston extendible and retractable from an actuator cylinder; cooperative locking means between the piston and the cylinder adapted to lock and 25 unlock the piston in an extended and a retracted position; wherein to couple the implement, hydraulic pressure in a first circuit extends the piston whereby the latches are moved to connect with the mounting bars, and the piston is locked in the implement engaging position; wherein to decouple the implement, 30 hydraulic pressure in a second circuit unlocks and retracts the piston to the implement disengaging position to disconnect the latches from the mounting bars. -2- Preferably, the cooperative locking means between the piston and the cylinder adapted to lock and unlock the piston in an extended and a retracted position comprises: one or more circumferential raised projections on the surface of the piston forming a backstop or a ratchet, respectively; 5 a gland to seal the piston with the cylinder; the gland including one or more spring biased spools or pins adapted to engage the backstop or ratchet to lock the piston in an extended position; fluid pressure in a first circuit to extend the piston wherein the spools or pins are overridden by the backstop or a ratchet until they engage a projection at the end of the piston's 10 extension, and fluid pressure in a second circuit to overcome the spring bias of and withdraw the spools or pins and to retract the piston. Preferably, the actuator of the coupler further operates a mounting bar lock wherein extension 15 of the actuator locks a mounting bar in a latch and wherein the retraction of the actuator releases the mounting bar lock before the implement can be disengaged. Preferably, the coupler has spring safety means adapted to urge and retain the latches under constant spring tension to prevent the latches moving from a default implement engaging 20 position to an implement disengaging position and/ or to keep the mounting bar lock engaged with a mounting bar in the absence of or low hydraulic fluid pressure or failure of the actuator. Preferably, the spring safety means comprises one or more tension springs. 25 In the alternative, the spring safety means comprises one or more torsion springs. Preferably, the spring safety means must be positively overridden by intentional retraction of the actuator to disengage an implement. 30 Preferably, the latches are semi-circular hook latches adapted to engage and disengage mounting bars of a cylindrical configuration. -3- Preferably, 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. In one example, the coupler is specially adapted to be connected to a swivel device or apparatus 5 between the coupler and the articulated arm of the earth moving equipment to enable the coupler to swivel in a side to side motion. 10 BRIEF DESCRIPTION OF DRAWINGS: 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 cross sectional views of a preferred actuator of the 15 invention. Figure 1C shows a perspective view of the preferred actuator of the invention. Figure 2A and Figure 2B, show a perspective view and a cross sectional view of a coupler using the actuator of Figure 1. 20 Figure 3A , Figure 3B and Figure 3C show various perspective views of the actuator and spring safety means. Figure 4 shows a perspective view of an actuator piston. 25 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. 30 Referring to Figure 1A and Figure 11, there is shown cross sectional views of a preferred actuator 1 in the extended and the retracted positions, respectively. Figure IC shows a perspective view of the preferred actuator of the invention. -4- Actuator piston 2 is extendible and retractable from actuator cylinder 3 and is in sealing connection with the internal wall of actuator cylinder 3a. Actuator piston rod 2a has one or more circumferential raised projections 4, 5 on its surface 5 comprising a ratchet. Actuator cylinder has a gland 6 with one or more spring biased spools or pins 7, 8 adapted to engage ratchet to lock the piston in an extended position. Hydraulic pressure in a first circuit 9a extends piston wherein the ratchet overrides the spring biased spools or pins. Hydraulic pressure in a second circuit 9b retracts piston on first withdrawing the spools or pins from the ratchet. 10 Referring to Figure 2A and Figure 2B, there is shown a cross sectional view and perspective view of a preferred coupler 10 in the implement engaging position. The coupler's frame comprises side walls 12, 14 adapted to be attached to an articulated arm of earth moving equipment (not 15 shown). In the example the front and rear latches 16, 18 are semi-circular hook latches adapted to engage and disengage mounting bars of a cylindrical configuration (not shown). The actuator 20 moves rear pivoting latch 18 relative to front fixed latch 16 between the implement engaging position as shown and the implement disengaging position (not shown). 20 Hydraulic pressure in a first circuit 9a extends the piston assembly 2 wherein the ratchet 23 overrides the spring biased spools or pins 7, Sand the latches are moved to connect with the mounting bars, and the piston locked in the implement engaging position. Actuator 20 pivots at one end about sliding pin 22 which is connected to mounting bar lock 24. 25 Hydraulic pressure in a second circuit withdraws the spools or pins from the ratchet before retracting the piston to the implement disengaging position to disconnect the latches from the mounting bars. Retraction of the actuator 20 causes lock 24 to retract away from and disengage a front mounting bar (not shown) and latch 18 to move to the implement disengaging position. Extension of the actuator 20 causes mounting bar lock 24 to engage and lock a 30 mounting bar(not shown) in front latch whereas retraction of the actuator 20 withdraws the mounting bar lock 24. The ratchet 23 and the spools or pins 7, 8 when engaged retain actuator piston 2 in the extended position thereby preventing latches 16, 18 moving from the default and implement engaging position to the implement disengaging position in the absence of or low -5hydraulic fluid pressure or failure of the actuator. Front and rear latches 16, 18 are semi-circular hook latches adapted to engage and disengage mounting bars of a cylindrical 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 5 coupler and any attached implement to swivel in a side to side motion in addition to the articulations of the arm. Referring to Figures 3A to 3C, there is shown a various perspective views of the actuator and the spring safety means. In the example the rear latch 18 is a semi-circular pivoting hook latch 10 adapted to engage and disengage a rear mounting bar (not shown).To release an implement, actuator 20 retracts pivoting latch 18 to the implement disengaging position. Actuator 20 additionally operates mounting bar lock 24 associated with front latch (not shown).wherein the retraction of the actuator ram 22 withdraws the mounting bar lock 24 as rear latch 18 is pivoted to the implement disengaging position. Tension springs 26,28 and 30,32, comprising the spring 15 safety means are adapted to urge and retain the latch 18 and lock 24 under constant spring tension in a default implement engaging position independently but cooperating with actuator 20. The springs' tension is only overridden by positive and intentional retraction of the actuator ram 22 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 20 latches moving to the implement disengaging position. Figure 4 shows a perspective view of an actuator piston assembly 2 with circumferential raised projections 4, 5 on its surface which comprise the ratchet. 25 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. 30 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 -6variations on the terms "comprising" and "containing" such as "comprise", "comprises", "contain" and "contains". - 7-

Claims (10)

1. A safety coupler assembly for earth moving implements having an internally locking actuator 5 for 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 engagement with the mounting bars; an actuator to move a pivoting latch between an implement engaging position and an 10 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; the actuator having an actuator piston extendible and retractable from an actuator cylinder; cooperative locking means between the piston and the cylinder adapted to lock and unlock the piston in an extended and a retracted position; 15 wherein to couple the implement, hydraulic pressure in a first circuit extends the piston whereby the latches are moved to connect with the mounting bars, and the piston is locked in the implement engaging position; wherein to decouple the implement, hydraulic pressure in a second circuit unlocks and retracts the piston to the implement 20 disengaging position to disconnect the latches from the mounting bars.

2. The coupler of Claim 1 wherein the cooperative locking means comprises: one or more circumferential raised projections on the surface of the piston forming a backstop or a ratchet, respectively; 25 a gland to seal the piston with the cylinder; the gland including one or more spring biased spools or pins adapted to engage the backstop or ratchet to lock the piston in an extended position; fluid pressure in a first circuit to extend the piston wherein the spools or pins are overridden by the backstop or a ratchet until they engage a projection at the end of the piston's 30 extension, and fluid pressure in a second circuit to overcome the spring bias of and withdraw the spools or pins and to retract the piston. -8-

3. The coupler of Claim 1 or Claim 2 wherein the actuator further operates a mounting bar lock wherein extension of the actuator locks a mounting bar in a latch and wherein the retraction of the actuator releases the mounting bar lock before the implement can be disengaged. 5

4. The coupler of Claim 3 wherein there is spring safety means adapted to urge and retain the latches under constant spring tension to prevent the latches moving from a default implement engaging position to an implement disengaging position and/or to keep the mounting bar lock engaged with a mounting bar in the absence of or low hydraulic fluid pressure or failure of the 10 actuator.

5. The coupler of Claim 4 wherein the spring safety means must be positively overridden by intentional retraction of the actuator to disengage an implement. 15

6. The coupler of Claim 4 wherein the spring safety means comprises one or more tension springs.

7. The coupler of Claim 4 wherein the spring safety means comprises one or more torsion springs. 20

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

9. The coupler of any one of the above claims wherein there are projections or lugs associated 25 with the frame adapted to function as stops to limit the travel of the latches or any other components in one or more directions.

10. The coupler of any one 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 30 equipment to enable the coupler to swivel in a side to side motion. -9-