Linkage arrangement for a multi-purpose vehicle

• US 5,188,502 A
• Filed: 12/24/1990
• Issued: 02/23/1993
• Est. Priority Date: 12/24/1990
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Hopkins, Michael F., Quant, Wilton E., Tonsor, Andrew J., Allen, William E., Hosseini, Javad
• Primary Examiner(s): Huppert, Michael S.
• Assistant Examiner(s): Underwood, Donald W.
• Application Number:
  US07/632,839
• Time in Patent Office: 792 Days
• Field of Search: 414/700, 414/701, 414/702, 414/699, 414/697
• US Class Current: 414/700
• CPC Class Codes: E02F 3/433 horizontal, e.g. self-levelling

Abstract

Construction vehicles of the type having a pair of lift arms extending from the frame to support a work implement, have generally been restricted to operating one specific tool. The attempt to combine the operation of several different work implements has been met with severe functional restrictions since some work implements have specific requirements not found in the operation of others. In order to provide a lift arm linkage arrangement that incorporates the functional requirements necessary to operate a plurality of work implements while maintaining a simple, yet efficient construction, an electronic controller has been included in the design. The electronic controller includes a plurality of sensors that are operatively associated with the lift and tilt linkage of the lift arm arrangement. The sensors enable the electronic controller to constantly monitor the current position of the lift arms and the work implement and compare them with a programmed sequence of movements. The electronic controller is further able to automatically adjust the position of the lift arms and the work implement in accordance with the programmed sequence.

Claims

1. A linkage arrangement adapted for connecting a work implement to a frame of a vehicle comprising:

a pair of lift arms having a first end portion connected to the vehicle frame and a second end portion connected to the work implement, said lift arms being positioned in spaced, parallel relation to each other on opposite sides of a longitudinal centerline defined by the vehicle;

a lifting means for providing movement of the lift arms about the first end portions thereof in a generally vertical plane, said lifting means being positioned in generally vertical alignment with each of the respective lift arms;

a pair of first tilt links having a first end portion pivotally mounted to the work implement and a second end portion, said first tilt links being positioned in substantially the same vertical plane as that of the respective lift arms;

a pair of second tilt links having a first end portion pivotally connected to the respective lift arms and a second end portion pivotally mounted to the first tilt links at a location that is intermediate the first and second end portions of the first tilt links, said second tilt links being positioned in substantially the same vertical plane as that of the respective lift arms;

a tilting means for providing rotation of the work implement about its mounting to the lift arms, said tilting means having a pair of fluid actuated cylinders pivotally connected directly between the respective second end portions of the first tilt links and the vehicle frame and positioned in substantially the same vertical plane as that of the respective lift arms; and

electronic control means for measuring the actual angular relationship of the work implement with respect to the lift arms, calculating the variance between said actual angular relationship of the work implement to that of a predetermined angular relationship of the work implement with respect to the vehicle and controlling the tilting means to achieve and maintain said predetermined angular relationship of the work implement throughout the movement of the lift arms.

2. The linkage arrangement as set forth in claim 1 wherein the lifting means includes a pair of fluid actuated cylinders having first and second end portions, said first end portions being connected to the vehicle frame at spaced locations that are generally in vertical alignment with and beneath the respective mountings of the first end portions of the lift arms and said second end portions being connected to the respective lift arms at a central portion thereof.

3. A linkage arrangement as set forth in claim 1 wherein the electronic control means includes a plurality of sensors to measure the amount of movement of the lift arms about the mounting of the first end portion thereof and the rotation of the work implement with respect to the lift arms.

4. The linkage arrangement as set forth in claim 3 wherein the electronic control means includes a plurality of displacement sensors that are positioned within the fluid actuated cylinders of the lifting and tilting means to determine the positions of the lift arms with respect to the frame and the work implement with respect to the lift arms.

5. The linkage arrangement as set forth in claim 3 wherein the electronic control means includes a plurality of rotational angle sensors to measure the amount of movement of the lift arms about the mounting of the first end portions thereof and the rotation of the work implement with respect to its mounting to the lift arms.

6. The linkage arrangement as set forth in claim 4 wherein the electronic control means further includes a controller that receives the output from the sensors to determine the current positions of the lift arms and work implement, compares the respective current positions with that of a preselected desired position for the respective components and produces an output that actuates an electro-hydraulic valve that is associated with the fluid actuation cylinders of the lift and tilt means to adjust their respective positions in accordance with the preselected positions of the lift arm and work implement.

7. In a vehicle having a frame and being adapted to utilize a plurality of work implements, a linkage arrangement adapted to attach said implements to said frame, comprising:

a pair of lift arms having first and second end portions, said lift arms being mounted in spaced, parallel relation to one another with the first end portions thereof being pivotally mounted to the frame and the second end portion thereof being pivotally mounted to one of said work implements;

a tilt linkage associated with each lift arm having a first tilt link having a first end portion pivotally mounted to the work implement and second end portion, and a second tilt link having a first end portion pivotally connected to the lift arm and a second end portion pivotally mounted to the first tilt link at a location that is intermediate the end portions of the first tilt link, said tilt linkage being positioned in generally vertical alignment with the respective lift arms and being sufficient to provide rotational movement of the work implement about its mounting with the lift arms;

a first fluid actuator pivotally connected directly between the vehicle frame and each of the respective lift arms to provide movement of the lift arms in a generally vertical plane, each of said first fluid actuators being positioned to be generally in vertical alignment with the respective lift arm and its mounting to the vehicle frame;

a second fluid actuator pivotally connected between each tilt linkage and the vehicle frame, said fluid actuator being positioned so as to be generally in vertical alignment with the respective lift arms and tilt linkage; and

means for sensing the current position of the respective lift arms with respect to the vehicle, and the work implement with respect to the lift arms and providing coordinated manipulation of the first and second fluid actuators to move the lift arms and the work implement through a preselected sequence of maneuvers to a preselected position.

8. The linkage arrangement as set forth in claim 7 wherein the first and second fluid actuators are hydraulic cylinders that further include:

a first end portion attached to the frame;

a second end portion that extends from the first end portion and is attached to one of the respective lift arms and tilt linkages, said second end portions being moveable with respect to the first end portions to cause pivotal movement of the respective lift arms and work implements; and

a displacement sensor positioned within the first end portion to determine the amount of movement between the first and second end portions thereof.

9. The linkage arrangement as set forth in claim 7 wherein rotation angle sensor is connected to selected pivotal mountings of the lift arms, tilt linkage and work implement to determine the joint angle measurements of the lift arms and work implement relative to their respective mountings.

10. The linkage arrangement as set forth in claim 7 wherein a controller is in communication with the output of one of the sensing means to determine the actual position of the work implement and the lift arms and compare the actual position thereof with preselected positions of the lift arms and work implement that have been programmed therewithin.

11. The linkage arrangement as set forth in claim 10 wherein an electro-hydraulic actuator is in communication with the first and second fluid actuators and is responsive to an output from the controller to control the movement of the first end portion of the fluid actuators with respect to the second end portions thereof, to provide automatic operation of the fluid actuators.

12. In a vehicle having a frame and being of a construction sufficient for manipulating a plurality of work implements, a linkage arrangement adapted to mount the work implement to the vehicle comprising:

a pair of lift arms, each having a first end portion pivotally mounted to the frame and a second end portion pivotally mounted to the work implement, said lift arms being spaced from one another on

a lift cylinder operatively associated with each lift arm, said lift cylinders having a first end portion pivotally mounted to the frame, and a second end portion pivotally mounted to one of the respective lift arms, said lift cylinders being positioned in general alignment with the respective lift arms and being operable for moving the lift arms in a generally vertical plane about the mounting of the first end portion of the lift arms;

a first tilt link operatively associated with each lift arm and having a first and second end portion, said first end portion being pivotally mounted to the work implement in spaced, generally vertical alignment with the mounting of the second end portion of each lift arm;

a pair of second tilt links operatively associated with each lift arm, each having a first end portion pivotally connected to the lift arm on opposite sides thereof and a second end portion pivotally mounted to the first tilt link on opposite sides thereof at a location that is intermediate the first and second end portions of the first tilt link to form an extension between the point of attachment between the first and second tilt links;

a tilt cylinder operatively associated with each lift arm and having a first end portion mounted directly to the frame and a second end portion mounted to the second end portion of each first tilt link, said tilt cylinder being positioned to be spaced vertically above and in general vertical alignment with each of the respective lift arms; and

electronic control means for sensing the actual position of the lift arms with respect to the vehicle frame and the work implement with respect to the lift arms, calculating the variance between the respective actual positions and that of one of a plurality of preselected, programmable positions, and actuating the lift and tilt cylinders to reuse the movement of the lift arms and work implement in accordance with the preselected positions.

13. The linkage arrangement as set forth in claim 12 wherein the lift and tilt cylinders each include a cylinder body and a rod member that is reciprocally mounted within the cylinder body for movement between an extended and retracted position.

14. The linkage arrangement as set forth in claim 13 wherein the electronic control means includes a position sensor in the form of a displacement sensor that is positioned within each of the lift and tilt cylinders to determine the amount of extension of the rod member with respect to the cylinder body.

15. The linkage arrangement as set forth in claim 14 wherein the electronic control means includes a position sensing means in the form of a rotational angle sensor one of which is positioned about the pivotal connections between the lift arms and the frame and another of which is positioned about one of the pivotal mountings of the work implement or tilt linkage associated therewith, said rotational angle sensing means being of a construction sufficient for measuring the variance in angles between the selected relatively rotating components.

16. The linkage arrangement as set forth in claim 15 wherein the electronic control means includes a controller that receives the input from the sensing means and compares them to a preselected programmed position for the lift arms and the work implement contained within the controller and provides an output for manipulating the lift and tilt cylinders to position the lift arms and work implement in accordance with the preselected positions.

17. The linkage arrangement as set forth in claim 12 wherein the lift and tilt cylinders are in communication with an electro-hydraulic actuator that receives an output from the electronic control means and hydraulically actuates the lift and tilt cylinders in response thereto.

18. A linkage arrangement adapted for connecting a work implement to the frame of a vehicle comprising:

a pair of lift arms having a first end portion connected to the vehicle frame and a second end portion connected to the work implement, said lift arms being positioned in spaced, parallel relation to each other on opposite sides of a longitudinal centerline (X) defined by the vehicle;

a pair of lift cylinders having first and second end portions, said first end portions being connected to the vehicle frame at spaced locations that are generally in vertical alignment with and beneath the respective mountings of the first end portions of the lift arms and said second end portions being connected to the respective lift arm at a central portion thereof, said lift cylinders being so constructed and adapted to provide rotational movement of said lift arms about said first end portions, said movement being in a substantially vertical plane;

a pair of first links having first and second end portions, said first links being laterally spaced from one another and positioned in generally vertical alignment with the lift arms, said first end portion of each first link being pivotally connected to said work implement;

a pair of second links having first and second end portions, each of said second links being associated with opposing ones of the lift arms and the first links so as to be laterally spaced from one another in generally vertical alignment with the lift arms said first end portion of each second link being pivotally connected to the respective lift arm, said second end portion of each second link being pivotally connected to the respective first link at a point that is intermediate it end portions

a pair of tilt cylinders having first and second end portions, said first end portion being pivotally connected directly to said frame, said second end portion of each tilt cylinder being pivotally connected to the second end portion of the respective first link, said tilt cylinders being positioned in generally vertical alignment with the lift arms in a manner sufficient to provide rotational movement of said work implement about said lift arms;

means for sensing the actual position of the lift arm with respect to the frame and responsively producing a first position signal;

means for sensing the actual position of the work implement with respect to the lift arm and responsively producing a second position signal; and

electronic control means receiving said first and second position signals and responsively actuating said lift cylinder and said tilt cylinder in accordance with a set of predetermined steps.

19. A linkage arrangement, as set forth in claim 18, wherein said lift arm position sensing means and said work implement position sensing means each include a rotation angle sensor.

20. A linkage arrangement, as set forth in claim 18, wherein said lift arm position sensing means and said work implement position sensing means each include a cylinder extension sensor.

21. A linkage arrangement, as set forth in claim 18, wherein said electronic control means includes a programmable microprocessor.

22. A linkage arrangement, as set forth in claim 18, wherein said electronic control means implements a position feedback control.

23. A linkage arrangement, as set forth in claim 18, including:

a first control lever movable in two directions along an axis and responsively producing a first control signal;

a second control lever movable in two directions along an axis and responsively producing a second control signal;

wherein said electronic control means includes means for receiving said first control signal and responsively actuating said lift cylinders and for receiving said second control signal and responsively actuating said tilt cylinders.

24. A linkage arrangement, as set forth in claim 23, wherein said electronic control means includes means for determining an angular relationship of said work implement with respect to said work vehicle and for maintaining said angular relationship during movement of said lift arm.

25. A linkage arrangement, as set forth in claim 23, wherein said electronic control means includes means for positioning said work implement at a plurality of predetermined positions through actuation of said lift and tilt cylinders.