US20140096419A1

US20140096419A1 - Work tool coupler linkage

Info

Publication number: US20140096419A1
Application number: US13/661,814
Authority: US
Inventors: George Pinther; Sage Smith; John Salay; Florin Neamtu; Leigh Reeves
Original assignee: Caterpillar SARL
Current assignee: Caterpillar SARL
Priority date: 2012-10-08
Filing date: 2012-10-26
Publication date: 2014-04-10

Abstract

An electrically actuated coupling device for a machine and an implement is disclosed. The device includes a frame and an electric motor coupled to a drive shaft that extends between right and left ends of the frame. The motor causes the shaft to extend or retract from each end of the frame simultaneously. Each end of the frame includes a guide for receiving a latch. Each latch is pivotally coupled to a spring and each spring is pivotally coupled to a specially shaped lever which is pivotally coupled to the frame as well as an end of the shaft. The electric motor may be activated by the operator from within the cab.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 13/647,105, filed on Oct. 8, 2012.

TECHNICAL FIELD

This disclosure relates generally to a quick coupling device for a tool/implement for a machine and, more particularly, to a quick coupling device that may be actuated by the operator from the cab of the machine.

BACKGROUND

Machines frequently have lift arms with tools or implements disposed at the ends of the lift arms. The tools or implements may include as buckets, blades and the like. To simplify and expedite the exchanging or replacement of such tools, the lift arms are typically equipped with an attachment frame that includes coupling devices for quickly coupling and decoupling the various implements from the frame. Some of these coupling devices may also be power-operated to reduce the necessity for manual intervention and for ease of operation. Further, some coupling devices may be actuated from inside the cab of the machine.
In U.S. Pat. No. 6,866,467, a hydraulically-actuated quick coupling device includes an attachment frame. A pair of latch members is disposed at each end of the attachment frame and the latch members are movable between a latched position and an unlatched position. A link has first and second end portions with the first end portion of the link connected to the latch member. A pivot member has first and second end portions and a central portion with the first end portion pivotally connected on the attachment frame and the second end portion pivotally connected on the second end portion of the link. A cylinder has a head end connected to the attachment frame and a rod end connected to the central portion of the pivot member. The cylinder is operable for moving the latch member between the disengaged and engaged positions.
A low amount of force is required when the tool and coupler are very clean, but in dirty conditions or with a lack of scheduled lubrication or maintenance, the linkage can stick or jam, causing the operator to have to use a pry bar to force the linkage loose and engage/disengage the work tool.

SUMMARY

In one aspect, an electrically actuated coupling device is disclosed. The disclosed device may include a frame having a right end and a left end. The disclosed device may also include an electric motor with a drive shaft extending between the right and left ends of the frame. The motor may be used to cause the shaft to expand outwards towards the right and left ends of the frame simultaneously and to retract the shaft inwards away from the left and right ends of the frame simultaneously. The right end of the frame may include a right guide for slidably receiving a right latch. The left end of the frame may include a left guide for slidably receiving a left latch. The right latch may be pivotally coupled to a right spring. The right spring may pivotally couple the right latch to a right lever at a first pivot point. The right lever may be pivotally connected to the frame at a second pivot point. The right lever may also be pivotally connected to the shaft at a third pivot point. Similarly, the left latch may be pivotally coupled to a left spring. The left spring may pivotally couple the left latch to a left lever at a fourth pivot point. The left lever may also be pivotally connected to the frame at a fifth pivot point. The left lever may also be pivotally connected to the shaft at a sixth pivot point. Further, an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points may range from greater than 20° to less than 35°, and, similarly, an angle between a third line extending through the fourth and fifth pivot points and a fourth line extending through the fifth and sixth pivot points may also ranges from greater than 20° to less than 35°.
In another aspect, a machine is disclosed that may include a cab. The machine may also include right and left lift arms that may be coupled to a frame having a right end and a left end. The machine may also include an electric motor with a drive shaft that extends between the right and left ends of the frame. The motor may cause the shaft to expand outwards towards the right and left ends of the frame simultaneously and retract inwards away from the left and right ends of the frame simultaneously. The right end of the frame may include a right guide for slidably receiving a right latch and the left end of the frame may include a left guide for slidably receiving a left latch. The right latch may be pivotally coupled to a right spring. The right spring may pivotally couple the right latch to a right lever at a first pivot point. The right lever may be pivotally connected to the frame at a second pivot point. The right lever may also be pivotally connected to the shaft at a third pivot point. The left latch may also be pivotally coupled to a left spring. The left spring may pivotally couple the left latch to a left lever at a fourth pivot point. The left lever may be pivotally connected to the frame at a fifth pivot point and the left lever may be pivotally connected to the shaft at a sixth pivot point. The machine may also include a control switch for controlling the motor wherein the control switch is disposed inside the cab. Further, the second and third pivot points are separated by a first length and the first and second pivot points are separated by a second length. The first length is greater than the second length. The fifth and sixth pivot points are separated by a third length and the fourth and fifth pivot points are separated by a fourth length. The third length is greater than the fourth length. A ratio of the first length to the second length ranges from greater than 1.31 to less than 1.75, and a ratio of the third length to the fourth length ranges from greater than 1.31 to less than 1.75.
In another aspect, a method for coupling and decoupling a tool to and from a machine having right and left lift arms is also disclosed. The method may include coupling a frame having a right end and a left end to the right and left lift arms. The frame may support an electric motor with a drive shaft extending between the right and left ends of the frame. The right end of the frame may include a right guide for slidably receiving a right latch and the left end of the frame may include a left guide for slidably receiving a left latch. The right latch may be pivotally coupled to a right spring and the right spring may pivotally couple the right latch to a right lever at a first pivot point. The right lever may also be pivotally connected to the frame at a second pivot point and to the shaft at a third pivot point. The left latch may be pivotally coupled to a left spring. The left spring may pivotally couple the left latch to a left lever at a fourth pivot point. The left lever may be pivotally connected to the frame at a fifth pivot point and to the shaft at a sixth pivot point. The method may include aligning the right and left latches with right and left openings in the tool. The method may further include activating the motor to expand the shaft outwards towards the right and left ends of the frame thereby causing the right and left latches to be received in the right and left openings of the tool. Further, the method may also include activating the motor to retract the shaft inwards away from the right and left ends of the frame thereby causing right and left latches to be withdrawn from right and left openings of the tool. Further, an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from about 13° to about 18° and an angle between a fourth line extending through the fifth and sixth pivot points and an axis of the shaft ranges from about 13° to about 18°.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a machine coupled to a bucket.

FIG. 2 is a plan view of a disclosed coupling device, with the latches in an intermediate position.

FIG. 3 is a perspective view of the disclosed coupling device, particularly illustrating the latches in an intermediate position.

FIG. 4 is a partial perspective view of the disclosed coupling device, particularly illustrating the right latch in an intermediate position.

FIG. 5 is a partial plan view of the disclosed coupling device, particularly illustrating the right latch in an intermediate position.

FIG. 6 is a partial plan view of the disclosed coupling device, particularly illustrating the left latch in an intermediate position.

FIGS. 7-8 are partial plan views showing the left latches and associated linkages in retracted and extended positions respectively.

FIG. 9 is another partial plan view of the disclosed coupling device, particularly illustrating the right latch in a retracted position and an angle defined by a line drawn through the first and second pivot points and a line drawn through the second and third pivot points as well as an angle defined by a line drawn through the third and second pivot points and an axis of the shaft; and

FIG. 10 is a plan view of the left lever of the disclosed coupling device.

DESCRIPTION

FIG. 1 illustrates a machine 10 that may be equipped with the quick coupling device 11 shown in FIG. 2. In the example shown, the machine 10 is a skid steer loader. The machine 10 includes a frame 16 that is supported above ground by a plurality of ground engaging elements 13. While the ground engaging elements 13 are wheels, in the example shown, this disclosure is also applicable to track-type machines as well. The machine 10 also includes a pair of spaced apart lift arms 14 and an implement 15, in the form of a bucket that may be coupled to the lift arms 14. The machine 10 may be used with a variety of implements, other than the bucket shown at 15. To quickly and easily disconnect or decouple the implement 15 from the machine 10, it would be advantageous to include a quick coupling/decoupling device like that shown at 11 in FIG. 2.
Turning to FIG. 2, the coupling device 11 includes a frame 16 with a right end 17 and a left end 18. The frame supports a motor 19 that drives an expandable and retractable shaft assembly 21. As will be apparent to those skilled in the art, the motor 19/shaft assembly 21 combination may be replaced by a hydraulic cylinder or another type of actuator and extendable member. The shaft assembly 21 includes a right end 22 and a left end 23. The right and left end 22, 23 of the shaft assembly 21 are coupled to right and left levers 24, 25 respectively. As will be explained in greater detail below, the right and left levers 24, 25 pivot when the shaft assembly 21 is expanded or retracted. For example, when the shaft assembly 21 is retracted, upward bias is imposed upon the right and left springs 26, 27 respectively. The right and left springs 26, 27, as explained in greater detail below, are coupled to right and left latches 28, 29 at the pivot points 20, 30 respectively. The right and left latches 28, 29 are used to couple the frame 16 to the implement 15 as shown in FIG. 1. Also shown in FIG. 2 are right and left guides 31, 32 which slidably receive the latches 28, 29 respectively.
Turning to FIG. 3, the right and left latches 28 are also shown in extended positions. To retract the latches 28, 29, the shaft assembly 21 is retracted inwardly, that is, both the right end 22 and the left end 23 are retracted inwards or away from the right and left ends 17, 18 of the frame 16. The right spring 26 may be pivotally coupled to the lever 24 at a first pivot point 33. The right lever 24 may be pivotally coupled to the right end 17 of the frame 16 at a second pivot point 34. Further, the right lever 24 may be pivotally coupled to the right end 22 of the shaft assembly 21 at a third pivot point 35. Similarly, the left lever 25 may be pivotally coupled to the left spring at a fourth pivot point 36. The left lever 25 may also be pivotally coupled to the left end 18 of the frame 16 at a fifth pivot point 37, and the left lever 25 may be pivotally coupled to the left end 23 of the shaft assembly 21 at a sixth pivot point 38.
Turning to FIG. 4, the right lever 24 includes a front plate 41 coupled to a rear plate 42. The plates 41, 42 may be welded together, connected together in some other fashion or may be a unitary structure. As shown in FIG. 4, the right end 22 of the shaft assembly 21 has been moved to the left in the orientation of FIG. 4 thereby biasing the third pivot point 35 to the left. This causes the right lever 24 to pivot about the second pivot point 34 in a downward direction as indicated by the arrow 43. Movement of the right lever 24 in the direction of the arrow 43 causes the first pivot point 33 to move downward thereby compressing the right spring 26. The right spring 26 which is pivotally coupled to the right latch 28 at the pivot point 20 presses the right latch 28 downward through the right guide 31 to the latching or coupling position shown in FIG. 4.
A plan view of the position shown in FIG. 4 is also shown in FIG. 5 and a plan view of the left side 18 of the frame in the coupled or extended position is shown in FIG. 6. Also shown in FIGS. 5-6 are shaped opening 44, 57 which can receive a tool in the event the coupling device 11 becomes stuck or jammed. Further, FIGS. 5-6 also illustrates the outwardly extending tabs 45, 47 of the front and rear plates 41, 42 and 141, 142 of the right and left levers 24, 25 respectively. The tabs 45, 47 are visible to the operator in the cab 46 of the machine 10 so the operator has a visual indication that the coupling device 11 is in the coupled or latched position shown in FIGS. 4-6. As shown in FIG. 9, the tab 45 is obscured and not clearly visible to the operator, thereby indicating to the operator that the coupling device 11 is in the decoupled or detached position shown in FIG. 3.
FIGS. 7-8 illustrate the retraction and extension of the left latch 29, which may operate in the same fashion as the right latch 28. In FIG. 7, the shaft assembly 21 has been retracted, or moved to the left in the orientation of FIGS. 7-8. The pivot point 38 of the lever 25 has been moved to the left and upwards, thereby causing the pivot point 36 to pull upward on the spring 27, which causes the left latch 29 to retract upward into the guide 32. Conversely, in FIG. 8, the shaft assembly 21 has been extended, or moved to the right in the orientation of FIGS. 7-8. The pivot point 38 of the lever 25 has been moved to the right and downwards, thereby causing the pivot point 36 to bias the spring 27 downwards, which causes the left latch 29 to outward from the guide 32.
FIG. 9 illustrates geometrically the improved performance of the coupling device 11. Specifically, the lever 24 includes three pivot points including the first pivot point 33, which pivotally couples the lever 24 to the spring 26. The lever 24 also includes a second pivot point 34 which may pivotally couple the lever 24 to the frame 16. Finally, the lever 24 includes a third pivot point 35 which may pivotally couple the lever 24 to the right end 22 of the shaft assembly 21. It has been found that an angle 51 defined by a first line 52 that extends through the first pivot point 33 and the second pivot point 34 and a second line 53 that extends through the second pivot point 34 and the third pivot point 35 may be greater than 20° and less than 35° for optimal operation. While the angle 51 may range from greater than 20° to less than 35°, a narrower range of from about 27° to about 31° may provide even better performance. In one example, the angle 51 may be about 29°. Similarly, another angle 54 has surprisingly been found to have an effect on the performance on the coupling device 11. The angle 54 is defined by the line 53 that extends through the second and third pivot points 34, 35 and the axis 55 of the shaft assembly 21. The angle 54 may range from greater than 10° to less than 25°. While the angle 54 may range from greater than 10° to less than 25°, a narrower range of from about 13° to about 18° may provide a more optimal performance. In one example, the angle 54 is about 16°.
The dimensions of the levers 24, 25 have also been surprisingly found to be useful in optimizing the performance of the coupling device 11. The left lever 25 is illustrated in FIG. 7. It also includes a shaped opening 57 for receiving a tool in the event the coupling device 11 becomes stuck or jammed. The fourth, fifth and sixth pivot points are shown at 36, 37, 38 respectively and they correspond to the first, second and third pivot points 33, 34, 35 of the right lever 24. The distance between the fourth and fifth pivot points is shown at 61. The distance between the fifth and sixth pivot points is shown at 62. It has been surprisingly found that the ratio of these two distances affects the performance of the coupling device 11. First, the length or length 62 is greater than the length or length 61. Further, a ratio of the length 62 to the length 61, for effective operation of the coupling device 11, may range from greater than 1 to about 1.5. While the ratio of the length 62:length 61 may range from greater than 1 to about 1.5, and more optimal performance may be found using a ratio falling within the range of from about 1.32 to about 1.45. In one embodiment, the ratio of the length 62 to the length 61 is about 1.4. It has been found that using two pivot points 36, 38 instead of a single pivot point coupling the lever 25 to both the left spring 27 and the shaft assembly 21 permits the coupling device 11 to have a higher engagement force, which enables the coupling device 11 to operate effectively in non-optimal conditions such as where corrosion may exist, debris or dirt may have infested the linkage, maintenance or lubrication may be required, etc.

INDUSTRIAL APPLICABILITY

The coupling device 11 has been described above. It may be used to quickly and easily change implements 15 on the machine 10 and the activation of the coupling device 11 may be performed by the operator in the cab 46. All that is required is that the right and left latches 28, 29 be aligned with corresponding openings in the tool or implement 15. Then the operator activates the motor 19 (or hydraulic system or actuator) to extend the shaft assembly 21 (or cylinder or extendable member) outward which results in the right and left latches 28, 29 extending downward through their respective guides into the openings of the tool or implement 15. Disengagement of the tool or implement 15 from the frame 16 is also easily accomplished by activating the motor and retracting the shaft assembly 21 laterally inwards away from the right and left ends 17, 18 of the frame 16.

Claims

1. An electrically actuated coupling device, comprising:

a frame having a right end and a left end;

an actuator or extendable member extending between the right and left ends of the frame, the actuator causing the extendable member to expand outwards towards the right and left ends of the frame simultaneously and to retract inwards away from the left and right ends of the frame simultaneously;

the right end of the frame including a right guide for slidably receiving a right latch, the left end of the frame including a left guide for slidably receiving a left latch;

the right latch pivotally coupled to a right spring, the right spring pivotally coupling the right latch to a right lever at a first pivot point, the right lever being pivotally connected to the frame at a second pivot point, the right lever being pivotally connected to the shaft at a third pivot point;

the left latch pivotally coupled to a left spring, the left spring pivotally coupling the left latch to a left lever at a fourth pivot point, the left lever being pivotally connected to the frame at a fifth pivot point, the left lever being pivotally connected to the shaft at a sixth pivot point;

wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from greater than 20° to less than 35°; and

wherein an angle between a third line extending through the fourth and fifth pivot points and a fourth line extending through the fifth and sixth pivot points ranges from greater than 20° to less than 35°.

2. The coupling device of claim 1 wherein the second and third pivot points are separated by a first length, the first and second pivot points are separated by a second length and the first length is greater than the second length; and

wherein the fifth and sixth pivot points are separated by a third length, the fourth and fifth pivot points are separated by a fourth length and the third length is greater than the fourth length.

3. The coupling device of claim 2 wherein a ratio of the first length to the second length ranges from greater than 1 to about 1.75; and

a ratio of the third length to the fourth length ranges from greater than 1 to about 1.75.

4. The coupling device of claim 3 wherein the ratios range from greater than 1.31 to about 1.45.

5. The coupling device of claim 1 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from greater than 20° to less than 35°; and

6. The coupling device of claim 1 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from greater than 27° to less than 31°; and

wherein an angle between a third line extending through the fourth and fifth pivot points and a fourth line extending through the fifth and sixth pivot points ranges from greater than 27° to less than 31°.

7. The coupling device of claim 1 wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from greater than 10° to less than 25°; and

wherein an angle between a fourth line extending through the fourth and fifth pivot points and an axis of the shaft ranges from greater than 10° to less than 25°.

8. The coupling device of claim 1 wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from about 13° to about 18°; and

wherein an angle between a fourth line extending through the fifth and sixth pivot points and an axis of the shaft ranges from about 13° to about 18°.

9. A machine comprising:

a cab;

right and left lift arms coupled to a frame having a right end and a left end;

an actuator with an extendable member extending between the right and left ends of the frame, the actuator causing the extendable member to expand outwards towards the right and left ends of the frame simultaneously and to retract inwards away from the left and right ends of the frame simultaneously;

the left latch pivotally coupled to a left spring, the left spring pivotally coupling the left latch to a left lever at a fourth pivot point, the left lever being pivotally connected to the frame at a fifth pivot point, the left lever being pivotally connected to the shaft at a sixth pivot point; and

wherein the second and third pivot points are separated by a first length, the first and second pivot points are separated by a second length and the first length is greater than the second length;

wherein the fifth and sixth pivot points are separated by a third length, the fourth and fifth pivot points are separated by a fourth length and the third length is greater than the fourth length; and

wherein a ratio of the first length to the second length ranges from greater than 1.31 to less than 1.75, and a ratio of the third length to the fourth length ranges from greater than 1.31 to less than 1.75.

10. The machine of claim 9 wherein the ratios range from greater than 1.31 to about 1.45.

11. The machine of claim 9 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from greater than 20° to less than 35°; and

12. The machine of claim 9 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from about 27° to about 31°; and

wherein an angle between a third line extending through the fourth and fifth pivot points and a fourth line extending through the fifth and sixth pivot points ranges from about 27° to about 31°.

13. The machine of claim 9 wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from greater than 10° to less than 25°; and

14. The machine of claim 9 wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from about 13° to about 18°; and

15. A method for coupling and decoupling a tool to and from a machine having right and left lift arms, the method comprising:

coupling a frame having a right end and a left end to the right and left lift arms, the frame supporting an actuator with an extendable member extending between the right and left ends of the frame, the right end of the frame including a right guide for slidably receiving a right latch, the left end of the frame including a left guide for slidably receiving a left latch, the right latch pivotally coupled to a right spring, the right spring pivotally coupling the right latch to a right lever at a first pivot point, the right lever being pivotally connected to the frame at a second pivot point, the right lever being pivotally connected to the shaft at a third pivot point, and the left latch pivotally coupled to a left spring, the left spring pivotally coupling the left latch to a left lever at a fourth pivot point, the left lever being pivotally connected to the frame at a fifth pivot point, the left lever being pivotally connected to the shaft at a sixth pivot point;

aligning the right and left latches with right and left openings in the tool;

activating the actuator to extend the extendable member outwards towards the right and left ends of the frame thereby causing the right and left latches to be received in the right and left openings of the tool; and

activating the actuator to retract the extendable member inwards away from the right and left ends of the frame thereby causing the right and left latches to be withdrawn from the right and left openings of the tool;

wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from about 13° to about 18° and wherein an angle between a fourth line extending through the fifth and sixth pivot points and an axis of the shaft ranges from about 13° to about 18°.

16. The method of claim 15 wherein the second and third pivot points are separated by a first length, the first and second pivot points are separated by a second length;

wherein the fifth and sixth pivot points are separated by a third length, the fourth and fifth pivot points are separated by a fourth length; and

wherein ratios of the first length to the second length and the third length to the second length range from greater than 1.31 to less than 1.75.

17. The method of claim 15 wherein the second and third pivot points are separated by a first length, the first and second pivot points are separated by a second length;

wherein ratios of the first length to the second length and the third length to the second length range from greater than 1.32 to about 1.40.

18. The method of claim 15 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from greater than 20° to less than 35°; and

19. The method of claim 15 wherein an angle between a first line extending through the first and second pivot points and a second line extending through the second and third pivot points ranges from about 27° to about 31°; and

20. The method of claim 17 wherein an angle between a second line extending through the second and third pivot points and an axis of the shaft ranges from about 13° to about 18°; and