The present invention relates to a control circuit. More particularly, the present invention relates to a control circuit for an attachment mounting device.
Attachment mounting devices or implement couplers are carried on the front of a loader arm and are used for quickly attaching and detaching various accessories or tools, such as buckets, pallet forks, augers, etc. Attachment mounting devices have been used extensively by Bobcat Company, a business unit of, Ingersoll-Rand Company, and sold under the mark Bobtachâ„¢. These quick attachment devices have been utilized quite extensively for the ease of changing between attachments on a loader.
More recently, attachment mounting devices utilize power actuators to automatically power operate the attachment and detachment of the various implements or tools for a loader. In one example, a power actuator is connected to manual levers for power operating movable wedge members that are used for locking an attachment in place onto the attachment mounting device. The wedge members are movable from a retracted position, in which an attachment can be slipped onto the attachment mounting device, to a latched position, in which the wedge members are forced through an opening on a bracket on the implement to positively lock the implement to the quick attachment device. The power actuator is operated through a hydraulic circuit.
Attachment mounting devices incorporate various features. One such feature includes a portion of the hydraulic circuit that automatically enables the attachment mounting device into a closed position regardless of the last commanded motion. For example, if an operator commands the attachment mounting device to latch an implement to the loader arm by actuating the attachment mounting device into a closed position, the hydraulic circuit automatically keeps the attachment mounting device in a closed position. If an operator commands the attachment mounting device to unlock an attachment device by actuating the attachment mounting device into an open position, the hydraulic circuit can automatically close the quick attachment device after the command to open. The above-describe feature is undesirable when trying to change attachments efficiently and quickly. Occasionally the feature facilitates attachment mounting device closings that are of a nuisance.
The present invention provides a control circuit for an attachment mounting device. The attachment mounting device has a closed position for securing an implement to a loader arm and an opened position for releasing the implement from the loader arm. The control circuit includes at least one hydraulic actuator configured to actuate the attachment mounting device into the closed position and into the opened position. The control circuit also includes a control valve. The control valve has at least a first energized position and a second energized position. The first energized position applies pressurized fluid to the at least one hydraulic actuator to actuate the attachment mounting device into the closed position. The second energized position applies pressurized fluid to the at least one hydraulic actuator to actuate the attachment mounting device into the opened position. The control circuit also includes an auto-close feature. The auto-close feature is configured to be activated after the control valve is in the first energized position. The auto-close feature is also configured to be deactivated after the control valve is in the second energized position. The activated auto-close feature applies pressurized fluid to at least one hydraulic actuator to keep or revert the attachment mounting device into the closed position.
The present invention also provides an attachment mounting device for attaching an implement to a loader. The attachment mounting device has a closed position for securing the implement and an opened position for releasing the implement. The attachment mounting device includes a pair of wedges configured in an extendable position when the implement is attached to the attachment mounting device and configured in a retractable position when the implement is detached from the attachment mounting device. The attachment mounting device also includes at least one hydraulic actuator configured to actuate the pair of wedges from the extendable position to the retractable position. An auto-close feature is configured to keep the pair of wedges extended when activated and configured to keep the pair of wedges retracted when deactivated.
Lift arm assembly 22 includes a pair of lift arms 26 on left and right sides of loader 10 and depending forearms 27 fixed to the forward or distal ends of lift arms 26. Lift arm assembly 22 is raised and lowered by pivoting the lift arm assembly about pivots 24 with actuators 25. Actuators 25 have base end pivots 27 connected to frame plates 20 and rod ends connected at pivots 28. Lift actuators 25 are extended and retracted by operator control in cooperation with the engine, pump and valve block located in the hydraulic power system.
Depending forearms 27 are connected to each other at pivot joint 30 and attachment mounting device 29 is coupled to depending forearms 27 at pivot joint 30. The tilting and mounting of implement 36 to attachment mounting device 29 is controlled by an actuator, the extendible and retractable rod of which is shown at 32 and attached to a suitable bracket 34. Attachment mounting device 29 is configured to mount or attach any of a variety of implements, such as implement 36, or attachments for temporary or permanent mounting. As depicted in
Attachment mounting device 29 is configured to latch or lock implement 36 to a work vehicle with sliding wedges 48. Attachment mounting device 29 includes left and right wedges 48 that are slidable in suitable guides for vertical movement between latched and unlatched positions. Each wedge 48 is moved by a link 58 connected to an upper end of the respective wedge 48 at 59. Each link 58 is connected to a bell crank. One of the links 58 is connected to a right bell crank 60 with a pivot pin 62 and the other of the links 58 is connected to a left bell crank 61 with a pivot pin 63. Right bell crank 60 is integrally formed with lever 66 and left bell crank 61 is integrally formed with lever 68. Levers 66 and 68 allow attachment mounting device 29 to mount to an implement manually or hydraulically.
Pivot pins 62 and 63 are also used for mounting the opposite ends of a power actuator 54 that actuates wedges 48. Power actuator 54 can be a hydraulic type actuator. As illustrated in
In general, control circuits for attachment mounting devices, similar to the ones illustrated in
Those skilled in the art should recognize that other actuator plumbing configurations for actuators 402, 502 and 503 are possible. In
Referring to
When electrical coil 410 becomes energized, a first energized position 413 of control valve 408 results. First energized position 413 allows hydraulic flow from pump 420 (or other source of pressurized flow), to be connected to hydraulic passage 422 and pilot signal passage 426. Pressure in pilot signal passage 426 is directed to dump valve 424 which builds sufficient pressure across control valve 408, into hydraulic passage 422, and to base end 406 of hydraulic actuator 402. Such a process configures attachment mounting device 29 (
When electrical coil 411 becomes energized, a second energized position 415 of control valve 408 results. Second energized position 415 allows hydraulic fluid, pressurized by pump 420, to be applied to rod end 404 of hydraulic actuator 402 and through hydraulic passage 436, thereby configuring attachment mounting device 29 to be actuated into an open position. In other embodiments, however, hydraulic passage 436 can couple to a base end of the actuator. In second energized position 415, hydraulic fluid from rod end 406 is allowed to drain through tank port 414 and through drain passage 418 to the hydraulic tank. After attachment mounting device 29 is actuated into an open position, electrical coil 411 is de-energized (by the operator) and control valve 408 reverts back to its neutral state.
Auto-close feature 428 includes a sequence valve 430, a hydraulic passage 432 and a port passage 429. Port passage 429 includes a first end 437 that couples to passage 421. Hydraulic passage 432 connects sequence valve 430 to end 435 that couples to hydraulic passage 422. However, in other embodiments hydraulic passage 422 can couple to a passage connected to a rod end of the actuator.
Sequence valve 430 has two positions (first position 433 and second position 431). Sequence valve 430 is actuated by two pilot signal passages (444 and 446). Pilot signal passage 444 connects passage 432 to the first end of sequence valve 430 and acts to move sequence valve 430 into first position 433. Pilot signal 446 connects passage 436 to the second end of sequence valve 430 and acts to move sequence valve 430 into second position 431.
When sequence valve 430 is in first position 433, the auto-close feature 428 is activated. When sequence valve 430 is in second position 431, the auto-close feature 428 is de-activated. In second position 431, sequence valve 430 prevents flow in passage 429 from passage 432, thus disabling the auto-close feature 428.
In addition, sequence valve 430 of auto-close feature 428 also includes a detent 438. Detent 438 acts to hold sequence valve 430 into first position 433 or second position 431. When detent 438 is in a first detent position, sequence valve 430 is held in its first position 433 and auto-close feature 428 is activated, which connects passage 429 to passage 432 and can provide flow to hydraulic actuator 402 to configure attachment mounting device 29 into a closed position. When detent 438 is in a second detent position sequence valve 430 is held in its second position 431 and auto-close feature 428 is de-activated, thus preventing pressurized fluid from automatically actuating hydraulic actuator 402 into a closed position.
Hydraulic circuit 400 includes other features such as pressure compensation flow controls 440 and 441 and non-return valve 442. Flow controls 440 and 441 provide some control as to the amount of pressure supplied to hydraulic actuator 402, while non-return valve 442 prevents fluid from draining towards passage 421.
Referring to
When electrical coil 510 becomes energized, a first energized position 513 of control valve 508 results. First energized position 513 allows hydraulic flow from pump 520 (or other source of pressurized flow), to be connected to hydraulic passage 522 and pilot signal passage 526. Pressure in pilot signal passage 526 is directed to dump valve 524 which builds sufficient pressure across control valve 508 into passage 522 to rod ends 506 and 507 of hydraulic actuators 502 and 503, thereby configuring attachment mounting device 29 (
When electrical coil 511 becomes energized, a second energized position 515 of control valve 508 results. Second energized position 515 allows hydraulic fluid, pressurized by pump 520, to be applied to base ends 504 and 505 of hydraulic actuators 502 and 503 through base end hydraulic passage 536, thereby configuring attachment mounting device 29 to be actuated into an open position. In other embodiments, however, hydraulic passage 536 can couple to a rod end of an actuator. In second energized position 515, hydraulic fluid from rod ends 505 and 507 are allowed to drain through tank port 514 and through drain passage 518 to the hydraulic tank. After attachment mounting device 29 is actuated into an open position, electrical coil 511 is de-energized (by the operator) and control valve 508 reverts back to its neutral state.
Auto-close feature 528 includes a sequence valve 530, a hydraulic passage 532 and a port passage 529. Port passage includes a first end 537 that couples to passage 521. Hydraulic passage 532 connects sequence valve 530 to end 535 that couples to hydraulic passage 522. In other embodiments, however, passage 532 can couple to a base end of an actuator.
Sequence valve 530 has two positions (first position 533 and second position 531). Sequence valve 530 is actuated by two pilot signal passages (544 and 546). Pilot signal passage 544 connects passage 532 to the first end of sequence valve 530 and acts to move sequence valve 530 into first position 533. Pilot signal 546 connects passage 536 to the second end of sequence valve 530 and acts to move sequence valve 530 into second position 531.
When sequence valve 530 is in first position 533, the auto-close feature 528 is activated. When sequence valve is in second position 531, the auto-close feature 528 is de-activated. In second position 531, sequence valve 530 prevent flow in passage 529 from passage 532, thus disabling auto-close feature 528.
In addition, sequence valve 530 of auto-close feature 528 includes a detent 538. Detent 538 acts to hold sequence valve 530 into first position 533 or second position 531. When detent 538 is in a first detent position, sequence valve 530 is held in its first position 533 and auto-close feature 528 is activated, which connects passage 532 to passage 529 and can provide flow to hydraulic actuators 502 and 503 to configure attachment mounting device 29 into a closed position. When detent 538 is in a second detent position, sequence valve 530 is held in its second position 531 and the auto-close feature 528 is activated, thus preventing pressurized fluid to automatically actuate hydraulic actuators 502 and 503 into a closed position.
Hydraulic circuit 500 includes other features such as pressure compensation flow controls 540 and 541 and non-return valve 542. Flow controls 540 and 541 provide some control as to the amount of pressure supplied to hydraulic actuators 502 and 503, while non-return valve 542 prevents fluid from draining towards passage 521.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.