CONTROL CIRCUIT FOR FRONT END LOADER

• US 3,726,428 A
• Filed: 02/04/1971
• Issued: 04/10/1973
• Est. Priority Date: 02/04/1971
• Status: Expired due to Term

• Current Assignee: Komatsu Dresser Company E Sunnyside 7TH St Libertyville IL A General Partnership Under The Uniform Partnership Act of The State of de
• Original Assignee: Arthur J. Howells Jr, Marvin D. Jennings, Wayne W. Lark
• Inventors: Lark, Wayne W., Jennings, Marvin D., Howells, Arthur J. Jr.
• Primary Examiner(s): Forlenza, Gerald M.
• Assistant Examiner(s): Mannix, John
• Application Number:
  US05/112,537
• Time in Patent Office: 796 Days
• Field of Search: 214/762,763,764,138,771,132,1CM
• US Class Current: 414/700
• CPC Class Codes: E02F 3/432 for keeping the bucket in a predetermined position or attitude
• CPC Class Codes: E02F 3/434 providing automatic sequences of movements, e.g. automatic dumping or loading, automatic return-to-dig

Abstract

There is disclosed a control circuit for actuating a hydraulically actuated boom and a hydraulically actuated implement associated with an earth-working mechanism whereby the actuation of the boom and the implement may be initiated solely by the closing of an electrical switch thereby enabling the operator of the earth-working mechanism to retain both hands on the steering wheel except for the short period of time when the switch is actuated. The control circuit comprises a first electrical circuit for automatically raising the boom and the implement, a second electrical circuit for automatically and continuously orienting the implement in a predetermined relationship with the boom, a third electrical circuit for automatically rotating the implement from a first position to a second position and wherein the third electrical circuit includes means for maintaining the implement in the second position for a preselected period of time and then automatically returning the implement to the first position, a fourth electrical circuit for lowering the boom and the implement, a fifth electrical circuit for automatically orienting the implement in a preselected angular relationship with the surface upon which the earthworking mechanism is located, and a sixth electrical circuit adapted to enable the boom and the implement to follow the surface upon which the earth-working mechanism is located. Each of these electrical circuits may be enabled in a preselected sequence by merely closing a switch which is located within easy access to the operator of the earth-working mechanism and in addition, a manual override control is available so that the operator may manually operate the boom and the implement in a conventional manner.

Claims

1. In a vehicle having an earth working mechanism including a hydraulically actuated boom and hydraulically actuated implement, a control circuit for actuating said boom and said implement comprising:

a first electrical circuit means, including a command means, first comparator means, and first, second and third variable impedances, for automatically raising said boom and said implement;

said command means including an electrical switch means and an electrical source wherein said actuation of said electrical switch means produces a signal adapted to automatically cause said boom to raise;

said first variable impedance associated with said boom and adapted to provide a first feedback signal indicative of the boom'"'"''"'"'s position;

said second variable impedance associated with said boom and adapted to effectuate movement of said boom in response to said first electrical signal;

said first comparator means interconnected between said first variable impedance, said second variable impedance and said command means for detecting and amplifying an impedance unbalance between said first and second impedances in response to said actuation of said electrical switch, wherein said resultant unbalance produces said first electrical signal which effectuates the movement of said boom and wherein movement of said boom causes a chanGe in said first feedback signal, thereby eliminating said unbalance;

said third variable impedance interconnected to said first comparator means wherein said boom may be raised to a first preselected height determined by the impedance of said third variable impedance; and

a second electrical circuit means for automatically and continuously orienting said implement in a preditermined relationship with said vehicle during the raising thereof.

2. The apparatus of claim 1 wherein said second electrical circuit means comprises:

a fourth variable impedance associated with said boom and adapted to provide a second feedback signal indicative of the position of said boom;

a fifth variable impedance associated with said implement and adapted to provide a third feedback signal indicative of the position of said implement;

a sixth variable impedance associated with said implement and adapted to effectuate a movement of said implement in response to a second electrical signal;

second comparator means interconnected between said fourth, fifth and sixth variable impedances for detecting and amplifying an impedance unbalance between said fourth, fifth and sixth variable impedances in response to the movement of said boom wherein said resultant unbalance produces said second electrical signal which effectuates the movement of said implement and wherein movement of said implement effectuates a change in said third feedback signal thereby eliminating said unbalance and continuously orienting said implement in a predetermined relationship with said boom.

3. The apparatus of claim 2 wherein each of said variable resistance comprises a potentiometer:

wherein the resistance of said first potentiometer and said fourth potentiometer is varied by the movement of said boom;

wherein the resistance of said fifth potentiometer is varied by the movement of said implement;

wherein the resistance of said second potentiometer is varied by the movement of a first hydraulic valve means associated with said boom; and

wherein the resistance of said sixth potentiometer is varied by the movement of a second hydraulic valve means associated with said implement.

4. The apparatus of claim 3 wherein said control circuit further comprises:

a third electrical circuit means for automatically rotating said implement from a first position to a second position and wherein said third electrical circuit means includes means for maintaining said implement in said second position for a preselected period of time and then automatically returning said implement to said first position.

5. The apparatus of claim 4 wherein said third electrical circuit means comprises means for electrically disconnecting said sixth potentiometer from said second comparator means for a preselected period of time wherein an unbalance signal occurs from said second comparator means when said sixth potentiometer is disconnected thereby causing said implement to move from said first position to said second position and return to said first position when said sixth potentiometer is reconnected to said second comparator means thereby eliminating said unbalance signal.

6. The apparatus of claim 5 wherein said control circuit further comprises:

a fourth electrical circuit means for lowering said boom and said implement to a second preselected height, and wherein said fourth electrical circuit includes a seventh potentiometer interconnected to said comparator means and means for disconnecting said third potentiometer from said first comparator means whereby said boom may be lowered to said second preselected height determined by the impedance of said seventh potentiometer.

7. The apparatus of claim 6 wherein said control circuit further comprises:

a fifth electrical circuit means for automatically disabling said second electrical circuit means when said boom reaches a third preselected height and wherein said fifth electrical circuit means automatically orients said impLement in a preselectable angular relationship with the surface upon which said earthworking mechanism is located.

8. The apparatus of claim 7 wherein said fifth electrical circuit means comprises:

an eighth potentiometer interconnected with said second comparator means; and

means for disconnecting said fourth potentiometer from said second comparator means whereby an unbalance signal is developed which causes the movement of said implement to a position determined solely by the impedance of said eighth potentiometer thereby establishing said preselectable relationship of said implement.

9. The apparatus of claim 8 wherein said control circuit further comprises:

a sixth electrical circuit means adapted to enable said boom and said implement to follow the contour of the surface upon which said earth-working mechanism is located, and wherein said sixth electrical circuit means includes a means for short circuiting said first comparator means whereby an uncorrectable unbalance signal results thereby enabling said boom and said implement to follow said contour.

10. The apparatus of claim 9 wherein said control circuit further comprises:

a first manual means for controlling the raising and lowering of said boom and said implement; and

a second manual means for controlling the position of said implement.