AU2021214412A1

AU2021214412A1 - Coupler for an excavator

Info

Publication number: AU2021214412A1
Application number: AU2021214412A
Authority: AU
Inventors: Zhengyu HE; Adrian MASON
Original assignee: Earthmoving Ind Engineering Pty Ltd
Current assignee: Earthmoving Industry Engineering Pty Ltd
Priority date: 2020-01-28
Filing date: 2021-01-27
Publication date: 2022-09-01
Also published as: AU2021107672A4; AU2021107672B4; KR20220002803U; CN214614271U; AU2024100026A4; AU2024100025A4; AU2021107672A9; AU2024100025B4; CN113250256A; WO2021151146A1; DE212021000303U1; JP3240613U

Abstract

An excavator coupler for coupling an excavator attachment to an arm of an excavator, the coupler includes a main body (11) having a first recess for engagement with a first pin of the attachment, a tongue member (15) moveable relative to the main body, the tongue member having a second recess (17) for engagement with a second pin of the attachment, a locking arm (19) pivotally mounted to the main body, and an actuator assembly (21) configured to i) move the tongue member relative to the main body to facilitate engagement and disengagement of the second recess with the second pin, and ii) pivot the locking arm to selectively block withdrawal of the first pin from the first recess. The actuator assembly includes a primary device configured to withdraw the locking arm from the first recess, and an auxiliary device for biasing the locking arm into the first recess. When the tongue member is retracted into abutment with a stop on the main body, the primary device can withdraw the locking arm from the first recess.

Description

COUPLER FOR AN EXCAVATOR

FIELD OF THE INVENTION

[0001] The present invention relates to an excavator coupler for coupling an excavator attachment, for example a bucket, to an arm of an excavator.

BACKGROUND TO THE INVENTION

[0002] An excavator coupler is used to connect an excavator with an excavator attachment, for example a bucket or other implements such as rippers, rocker breakers, grapples, rock saws, etc. For the sake of convenience, the invention will herein primarily be described with reference to an excavator bucket attachment. The coupler is attached to the arm of the excavator and is hydraulically operated to enable the operator of the excavator to change attachments quickly and easily, in most cases without the operator needing to move from the cab or operating position of the excavator. Attachments typically have a pair of parallel pins which engage with a pair of recesses formed in the coupler to connect the attachment.

[0003] Couplers typically include some form of mechanical lock to secure the attachment in the event of a hydraulic failure. In the past, couplers have relied on a manual safety pin to be fitted and removed each time the operator wanted to change an attachment. This required the operator to get off the excavator, remove the safety pin, then get back in the machine to release the hydraulic coupling and remove the existing attachment, pick-up the next selected attachment, then get down from the excavator to fit the safety pin, then get back into the excavator to operate. Due to this constant movement, many operators do not bother to fit the safety pin. Accordingly, if there is a malfunction in the hydraulics to the coupler, the attachment can fall off with potentially catastrophic results. [0004] It would be desirable to provide an excavator coupler of the above described general type which has one or more improved features.

[0005] Any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the invention. It should not be taken as an admission that any of the material formed part of the prior art base or the common general knowledge in the relevant art on or before the priority date of the claims herein.

SUMMARY OF THE INVENTION

[0006] In accordance with the present invention, there is provided an excavator coupler for coupling an excavator attachment to an arm of an excavator, the coupler including: a main body having a first recess for engagement with a first pin of the attachment, a tongue member moveable relative to the main body, the tongue member having a second recess for engagement with a second pin of the attachment, a locking arm pivotally mounted to the main body, and an actuator assembly configured to: i) move the tongue member relative to the main body to facilitate engagement and disengagement of the second recess with the second pin, and ii) pivot the locking arm to selectively block withdrawal of the first pin from the first recess.

[0007] The actuator assembly preferably includes a primary device mounted between the locking arm and the tongue member, and an auxiliary device for biasing the locking arm into the first recess, the primary device being configured to withdraw the locking arm from the first recess. The tongue member is in a fully retracted position when the tongue member is retracted into abutment with a stop on the main body. The primary device is preferably configured to withdraw the locking arm from the first recess once the tongue member is in the fully retracted position.

[0008] When the first recess is in engagement with the first pin and the primary device of the actuator assembly moves the second recess of the tongue member towards engagement with the second pin to couple the attachment to the arm, force applied by the primary device of the actuator assembly to move said tongue member, preferably pivots the locking arm into a locked position in which a portion of the locking arm locates in the first recess to block the first pin from withdrawal.

[0009] Said portion of the locking arm is preferably an end region which protrudes into the first recess at an acute angle relative to a wall of the first recess when said locking arm is in the locked position. Further, the end region of the locking arm preferably includes a bottom wall surface which abuts the first pin in said locked position. The bottom wall surface, in said locked position, may wedge into the first pin to prevent the first pin from withdrawing from the first recess.

[0010] The force applied by the primary device of the actuator assembly to move said tongue member and pivot the locking arm into the locked position is preferably provided in normal operation by a hydraulic actuator of the primary device.

[0011 ] The primary device of the actuator assembly may further include a secondary mechanism to maintain said coupling and pivot the locking arm into the locked position. More specifically, the secondary mechanism preferably continues to maintain said coupling and pivot the locking arm into the locked position in the event of a failure in the operation of the hydraulic actuator.

[0012] The hydraulic actuator preferably includes a cylinder body and a piston for extending and retracting the tongue member relative to the main body to thereby adjust the spacing between the first recess and the second recess. Preferably, the cylinder body is connected to the locking arm and the piston is connected to the tongue member with the connection of the cylinder body to the locking arm being below the pivotal mounting of the locking arm to the main body.

[0013] The secondary mechanism is preferably a biasing member which biases the tongue member and locking arm away from each other. The biasing member may be mounted between the cylinder body and the tongue member. More preferably, the biasing member is in the form of a compression spring mounted around the cylinder body. The hydraulic actuator is able to act against the compression spring during normal operation to move the tongue member towards the locking arm.

[0014] In one embodiment, the auxiliary device is mounted between the main body and the cylinder body. The auxiliary device functioning to provide a force to bias the cylinder body to maintain the locking arm in the locked position.

[0015] In a more preferred embodiment, the auxiliary device is mounted directly between the main body and the locking arm. The auxiliary device functioning to provide a force directly to the locking arm to bias the locking arm to maintain a locked position.

[0016] In one embodiment, the auxiliary device may include at least one compression spring supported at a lower end on a holder bar of the auxiliary device. The holder bar may include an upwardly projecting stub over which the lower end of the compression spring is seated. The holder bar may further include a cross member from which the stub projects. The cross member having a passageway therein through which a supporting pin can be located to mount the holder bar to the main body. The auxiliary device may further include a cap member which seats over an upper end of the compression spring. The cap member having an aperture therein to facilitate mounting of the cap member to the locking arm via a cap member pin which passes through the aperture in the cap member. The locking arm may include a pair of opposing tabs between which an upper end of the cap member is positioned. The opposing tabs each having an aperture therein to support opposite ends of the cap member pin.

[0017] In another embodiment, the auxiliary device may include a pair of torsion springs mounted on a pivot point of the locking arm adjacent opposing side flanges of the locking arm. Each opposing side flange may include an indentation upon which one end of the torsion spring is seated. An opposing end of each torsion spring preferably abutting with a downwardly projecting front portion of the main body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a perspective view of an excavator coupler in accordance with an embodiment of the invention attached to an arm of an excavator, the excavator coupler being in the process of coupling with an excavator attachment;

[0019] Figure 2 is a side perspective view of an excavator coupler in accordance with a first embodiment;

[0020] Figure 3 is an exploded view detail the components of the excavator coupler of the first embodiment illustrated in Figure 2;

[0021 ] Figure 4 is a side view of the excavator coupler of the first embodiment illustrated in Figure 2 showing the coupler securely engaged with the front and rear pins of an excavator attachment with the locking arm in a locked position;

[0022] Figure 5 is a side view of the excavator coupler of the first embodiment illustrated in Figure 2, showing the coupler in position in which the tongue member is fully retracted and disengaged with the rear pin, and the locking arm in a locked position in which the locking arm protrudes into the front recess to prevent release of the front pin; [0023] Figure 6 is a side view of the excavator coupler of the first embodiment illustrated in Figure 2, showing the coupler in a release position in which the tongue member is fully retracted and disengaged with the rear pin, and the locking arm in a retracted unlocked position clear of the front recess and front pin;

[0024] Figure 7 is a side perspective view of an excavator coupler in accordance with a second embodiment;

[0025] Figure 8 is an exploded view detail the components of the excavator coupler of the second embodiment illustrated in Figure 7;

[0026] Figure 9 is a side view of the excavator coupler of the second embodiment illustrated in Figure 7 showing the coupler in position in which the tongue member is fully retracted and disengaged with the rear pin, and the locking arm in a locked position in which the locking arm protrudes into the front recess to prevent release of the front pin, and

[0027] Figure 10 is a side view of an excavator coupler in accordance with a third embodiment, illustrating the position of the tongue member and locking arm in the event of a failure in the operation of the hydraulic actuator.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] With reference to the accompanying drawings, there is shown an excavator coupler 1 for coupling an excavator attachment 3, for example an excavator bucket to an arm 5 of an excavator. The attachment 3 includes a first, front pin 7 and a second, rear pin 9. The excavator coupler 1 is mounted at an end of the excavator arm 5 and is used to interconnect with and change various attachments 3, including excavator buckets, without the need for the operator to leave the cabin or operating position of the excavator. [0029] The excavator coupler 1 includes a main body 11 having a first, front recess 13, which may be in the form of a horizontal opening yoke, into which the front pin 7 of the attachment 3 can be engaged. The coupler 1 further includes a tongue member 15 which is movable relative to the main body 11. In this regard, the tongue member 15 is preferably able to slide back and forth along rails built into an underside of the main body 11. The tongue member 15 includes a second, rear recess 17 which is configured to engage with the second, rear pin 9 of the attachment 3.

[0030] The excavator coupler 1 further includes a locking arm 19 which is pivotally mounted to the main body 11 about a fix pivot point 12 above the front recess 13. The locking arm 19 is designed to lock the front pin 7 into the front recess 13 unless the coupler 1 is deliberately and hydraulically operated to release the front pin 7. More specifically, the locking arm 19 functions to restrain the front pin 7 from falling out of the front recess 13 in the event of a hydraulic failure such that the attachment 3 cannot inadvertently separate from the coupler 1 and compromise the safety of nearby workers.

[0031] The excavator coupler 1 further includes an actuator assembly configured to (i) slide the tongue member 15 along rails of the main body 11 to facilitate engagement and disengagement of the rear recess 17 with the rear pin 9 of the attachment 3, and (ii) pivot the locking arm 19 to selectively block withdrawal of the front pin 7 from the front recess 13. The actuator assembly includes a primary device 21 mounted between the locking arm 19 and the tongue member 15, and an auxiliary device 35 for biasing the locking arm 19 into the front recess 13.

[0032] As best illustrated in Figure 10, the primary device 21 preferably includes a hydraulic actuator having a cylinder body 23 and a piston/rod 25 for extending and retracting the tongue member 15 relative to the main body 11 , to thereby adjust the spacing between the front recess 13 and the rear recess 17. The cylinder body 23 has a base end 27 which is connected to the locking arm 19 via a pin 29 below the fixed pivot point 12 of the locking arm 19 on the main body 11. At the opposite end of the hydraulic actuator, the piston 25 is connected to the tongue member 15 via a mounting pin 31 or the like. In this regard, as illustrated in Figures 3 and 8, a mounting aperture 26 is provided at the end of the piston 25 and the tongue member 15 includes a pair of upstanding members 28 each having a bore 30. The end of the piston 25 locates between the upstanding members 28 such that the aperture 26 is in alignment with the bores 30. The mounting pin 31 is positioned through the bores 30 and the mounting aperture 26 to fasten the primary device 21 of the actuator assembly to the tongue member 15.

[0033] The primary device 21 further includes a secondary, fail-safe mechanism which biases the tongue member 15 and the locking arm 19 away from each other enabling the locking arm 19 to restrain the front pin 7 within the front recess 13 in the event of a hydraulic failure. In this regard, the secondary mechanism is a mechanical biasing member which is preferably in the form of a compression spring 33 which is mounted around the cylinder body 23 and piston/rod 25 of the hydraulic actuator.

[0034] The auxiliary device 35 of the actuator assembly functions to keep pressure on the locking arm 19 to maintain a locked position, as illustrated in Figures 4, 5, 9 and 10, in which the locking arm 19 protrudes downwardly into the first recess 13.

[0035] In a first embodiment of the excavator coupler illustrated in Figures 2 to 6, the auxiliary device 35 is mounted between the locking arm 19 and the main body 11. The auxiliary device 35 includes at least one high force compression spring, for example a die spring 36, which is supported at a lower end on a holder bar 38 of the auxiliary device 35. In this regard, the holder bar 38 includes a centrally located upwardly projecting stub over which the lower end of the die spring 36 is seated. The holder bar 38 further includes a tubular cross member from which the stub projects. The tubular cross member has a passageway therein through which a supporting pin 40 is located to mount the holder bar 38 to the main body 11. The auxiliary device 35 further includes a cap member 42 which seats over an upper end of the die spring 36. The cap member 42 has an aperture therein to facilitate mounting of the cap member 42 to the locking arm 19 via a cap member pin 44 which passes through the aperture in the cap member 42. The locking arm 19 includes a pair of forwardly projecting opposing tabs 46 between which an upper end of the cap member 42 is positioned. The opposing tabs 46 each have an aperture therein to support the ends of the cap member pin 44. The excavator coupler of this embodiment is particularly suitable for use with 4, 6 and 8 Tonne excavators. For larger excavators, for example, 14, 20, 25, 30 and 40 Tonne excavators, the auxiliary device 35 may utilize two die springs instead of one in the same manner as described above.

[0036] In the second embodiment of the excavator coupler illustrated in Figures 7 to 9, the auxiliary device 35 is mounted between the locking arm 19 and the main body 11. The auxiliary device 35 of this embodiment includes a pair of torsion springs 48 which are mounted on the fixed pivot point 12 of the locking arm 19 next to opposing side flanges of the locking arm 9. Each opposing side flange in this embodiment includes an indentation 50 upon which one end of the torsion spring 48 is seated. An opposing end of each torsion spring 48 abuts with a downwardly projecting front portion of the main body 11. The pressure applied by the torsion springs 48 biases the locking arm 9 in an anticlockwise direction when viewed side on as illustrated in Figure 9. The excavator coupler of this embodiment is particularly suitable for use with 2 Tonne excavators.

[0037] In the third embodiment of the excavator coupler illustrated in Figure 10, the auxiliary device 35 of the actuator assembly is positioned above the primary device with one end 52 of a compression spring connected to the main body 11 and an opposite end 54 connected to the cylinder body 23. The compression spring in this embodiment is designed to keep pressure on the base 27 of the cylinder body 23 which in turns keeps pressure on the locking arm 19 to bias the locking arm 19 in an anticlockwise direction when viewed as shown in Figure 10.

[0038] The excavator coupler 1 is preferably operated by an electric switch located in the cabin of the excavator. The switch preferably has a spring return as a fail-safe which automatically releases the switch when pressure on the switch is removed by the operator. The switch is preferably located in a position in the cabin where it cannot be unintentionally operated and ideally has an audible alarm when in operation. The switch functions to operate the hydraulic actuator to retract and extend the piston 25 relative to the cylinder body 23, as illustrated in Figure 6. When the tongue member 15 is disengaged with the rear pin and fully retracted into abutment with a stop 37 on the main body 11 , the locking arm 19 will still be in a locked position in which the locking arm 19 protrudes into the front recess 13 as illustrated in Figures 5 and 6. As the tongue member 15 is not able to retract any further due to engagement with the stop 37, further retraction of the piston 25 into the cylinder body 23 results in the cylinder body 23 being pulled rearwardly with the locking arm 19 in-turn being pulled causing the locking arm 19 to pivot clockwise, when viewed as shown in Figures 4 - 6. As the locking arm 19 pivots in the clockwise direction, it begins to retract from the front recess 13 until the excavator coupler 1 is in a fully retracted position in which the locking arm 19 is pivoted clockwise to a retracted unlocked position clear of the front recess 13 and front pin 7, as illustrated in Figure 6.

[0039] In order to couple an attachment 3 to the excavator, the tongue member 15 and locking arm 19 are firstly moved to the fully retracted position shown in Figure 6. The excavator arm 5 is then suitably maneuvered and the associated coupler 1 tilted downwards at the front so that the front pin 7 of the attachment 3 can be positioned into the front recess 13. Once the front pin 7 is in the front recess 13, the coupler 1 is then titled downwards at the rear until the main body 11 rests on the rear pin 9 of the attachment 3. The switch inside of the cabin is then released to automatically extend the hydraulic actuator. The hydraulic actuator of the coupler 1 is then extended such that the tongue member 15 moves rearwardly in a direction away from the front pin 9 and into engagement with the rear pin 9 of the attachment 3, as illustrated in Figure 4. The hydraulic actuator preferably applies full hydraulic pressure onto the rear pin 9 which ensures that the two pins 7, 9 are held hydraulically and cannot be disengaged.

In addition to the force provided by the positive pressure of the hydraulic actuator maintaining the engagement of the front pin 7 in the front recess 13 and the rear pin 9 in the rear recess 17, the force applied by the hydraulic actuator also pivots the locking arm 19 downwardly anticlockwise into a locked position, as illustrated in Figure 4, in which a portion of the locking arm 19 moves into the front recess 13 to block the front pin 7 from being withdrawn from the front recess 13. In this regard, the portion of the locking arm 19 which moves into the front recess 13 is preferably an end region which protrudes about 10mm down into the front recess 13 at an acute angle relative to an upper wall 39 of the front recess 13. The end region of the locking arm 19 may include a bottom wall surface which can abut the front pin 7 when the locking arm 19 is in the locked position. The bottom wall surface may include a stepped or V-shaped portion which, in said locked position, wedges down into the front pin 7 to prevent the front pin 7 from withdrawal. The positive pressure of the hydraulic actuator is maintained during normal operation with the force applied maintaining the engagement of the front pin 7 with the front recess 13 and the rear pin 9 with the rear recess 17, with the locking arm 19 being also held in the locked position. In order to release the pins 7, 9 from the coupler 1 , the switch inside of the excavator cabin is activated to retract the piston 25 into the hydraulic cylinder body 23 and thereby compress the compression spring 33. The locking arm 19 will not disengage with the front pin 7 until the tongue member 15 is fully retracted to abut with the stop 37.

[0040] As mentioned previously, a secondary, fail-safe mechanism in the form of compression spring 33 is provided around the cylinder body 23. The compression spring 33 is designed such that maximum pressure is provided on full extension of the hydraulic actuator. Accordingly, if a hydraulic failure occurs due to a malfunction, the compression spring 33 continues to maintain the pressure of the tongue member 15 on the rear pin 9 of the attachment 3 thereby ensuring that the attachment 3 cannot disconnect from the coupler 1. [0041] As illustrated in Figure 10, the rear recess 17 may include a secondary belly 45 into which the rear pin 9 may drop down in the event of a failure of the hydraulic actuator. In this regard, the compression spring 33 may permit a slight retraction of the tongue member 15 in the event of a failure of the hydraulic actuator. This in turn enables the coupler 1 and associated attachment 3 to slightly rotate about the front pin 7 such that weight is transferred from the rear pin 9 to the front pin 7. Due to the orientation of the coupler 1 , further pressure is put onto the locking arm 19 such that the arm 19 continues to prevent withdrawal of the front pin 7 from the front recess 13.

The present invention advantageously avoids the need for a safety pin to be manually fitted and removed each time an operator wants to change an attachment. Further, if there is a malfunction in the hydraulics to the coupler, the attachment can still not fall off due to the locking arm 19 being biased to a default position by the auxiliary device 35 in which the locking arm 19 protrudes into the first recess 13 to prevent the front pin 7 of the attachment from being removed.

Claims

CLAIMS:

1. An excavator coupler for coupling an excavator attachment to an arm of an excavator, the coupler including: a main body having a first recess for engagement with a first pin of the attachment, a tongue member moveable relative to the main body, the tongue member having a second recess for engagement with a second pin of the attachment, a locking arm pivotally mounted to the main body, and an actuator assembly configured to: i) move the tongue member relative to the main body to facilitate engagement and disengagement of the second recess with the second pin, and ii) pivot the locking arm to selectively block withdrawal of the first pin from the first recess.

2. An excavator coupler as claimed in claim 1 wherein the actuator assembly includes a primary device mounted between the locking arm and the tongue member, and an auxiliary device for biasing the locking arm into the first recess, the primary device being configured to withdraw the locking arm from the first recess.

3. An excavator coupler as claimed in claim 2 wherein the tongue member is in a fully retracted position when the tongue member is retracted into abutment with a stop on the main body, the primary device being configured to withdraw the locking arm from the first recess once the tongue member is in the fully retracted position.

4. An excavator as claimed in claims 2 or 3 wherein when the first recess is in engagement with the first pin and the primary device of the actuator assembly moves the second recess of the tongue member towards engagement with the second pin to couple the attachment to the arm, force applied by the primary device of the actuator assembly to move said tongue member, pivots the locking arm into a locked position in which a portion of the locking arm locates in the first recess to block the first pin from withdrawal.

5. An excavator coupler as claimed in claim 4 wherein said portion of the locking arm is an end region which protrudes into the first recess at an acute angle relative to a wall of the first recess when said locking arm is in the locked position.

6. An excavator coupler as claimed in claim 5 wherein the end region of the locking arm includes a bottom wall surface which abuts the first pin in said locked position.

7. An excavator coupler as claimed in claim 6 wherein the bottom wall surface, in said locked position, wedges into the first pin to prevent the first pin from withdrawing from the first recess.

8. An excavator coupler as claimed in any one of claims 3-7 wherein the force applied by the primary device of the actuator assembly to move said tongue member and pivot the locking arm into the locked position is provided in normal operation by a hydraulic actuator of the primary device.

9. An excavator coupler as claimed in claim 8 wherein the primary device of the actuator assembly further includes a secondary mechanism to maintain said coupling and pivot the locking arm into the locked position.

10. An excavator coupler as claimed in claim 9 wherein the secondary mechanism continues to maintain said coupling and pivot the locking arm into the locked position in the event of a failure in the operation of the hydraulic actuator.

11. An excavator coupler as claimed in any one of claims 7-10 wherein the hydraulic actuator includes a cylinder body and a piston for extending and retracting the tongue member relative to the main body to thereby adjust the spacing between the first recess and the second recess.

12. An excavator as claimed in claim 11 wherein the cylinder body is connected to the locking arm and the piston is connected to the tongue member, the connection of the cylinder body to the locking arm being below the pivotal mounting of the locking arm to the main body.

13. An excavator coupler as claimed in any one of claims 8-12 wherein the secondary mechanism is a biasing member which biases the tongue member and locking arm away from each other, the biasing member being mounted between the cylinder body and the tongue member.

14. An excavator coupler as claimed in claim 13 wherein the biasing member is in the form of a compression spring mounted around the cylinder body.

15. An excavator coupler as claimed in claim 14 wherein the hydraulic actuator is able to act against the compression spring during normal operation to move the tongue member towards the locking arm.

16. An excavator coupler as claimed in any one of claims 1 -15 wherein the auxiliary device is mounted between the main body and the locking arm, the auxiliary device providing a force directly to the locking arm to bias the locking arm to maintain a locked position.

17. An excavator coupler as claimed in claim 16 wherein the auxiliary device includes at least one compression spring supported at a lower end on a holder bar of the auxiliary device, the holder bar including an upwardly projecting stub over which the lower end of the compression spring is seated.

18. An excavator coupler as claimed in claim 17 wherein the holder bar further includes a cross member from which the stub projects, the cross member having a passageway therein through which a supporting pin is located to mount the holder bar to the main body.

19. An excavator coupler as claimed in claim 18 wherein the auxiliary device further includes a cap member which seats over an upper end of the compression spring, the cap member having an aperture therein to facilitate mounting of the cap member to the locking arm via a cap member pin which passes through the aperture in the cap member.

20. An excavator coupler as claimed in claim 19 wherein the locking arm includes a pair of opposing tabs between which an upper end of the cap member is positioned, the opposing tabs each having an aperture therein to support opposite ends of the cap member pin.

21. An excavator coupler as claimed in claim 16 wherein the auxiliary device includes a pair of torsion springs mounted on a pivot point of the locking arm adjacent opposing side flanges of the locking arm, each opposing side flange includes an indentation upon which one end of the torsion spring is seated, an opposing end of each torsion spring abutting with a downwardly projecting front portion of the main body.