Claims
- 1. A hydraulic circuit for selectively performing a first function at a first slower speed, at a second higher speed and not performing that function; and selectively for performing or not performing a second function, said circuit including:
- a first hydraulic pump;
- a first function motor;
- a first hydraulic path from said pump to said motor to carry fluid to drive said motor;
- said first path including a first function control valve;
- a second hydraulic pump;
- a second function motor;
- a second hydraulic path from said second pump to said second function motor to carry fluid to drive said second motor;
- said second path including in order from said second pump toward said second motor;
- a first function speed selector valve,
- an unloading valve, and
- a second function control valve; said speed selector valve being selectively operable:
- A. to form a part of said second path, and
- B. to block flow in said second path and to divert it to said first path to augment the output from said first pump to said first function control valve;
- said first function control valve being selectively operable:
- A. to form a part of said first path to permit fluid therein to pass to said first function motor to perform said first function, and
- B. to block flow in said first path to said first function motor and divert it to a first function control valve outlet line;
- said first function control valve outlet line opening to a one way check valve;
- said check valve opening to said second path between said unloading valve and said second function control valve;
- there being a pressure control line open from said first function control valve outlet passageway to said unloading valve;
- said unloading valve being operable responsive to the presence of a predetermined pressure in said pressure control line to divert flow of fluid from said second pump away from said second path;
- said second function control valve being selectively operable;
- A. to form a part of the second path to permit the passage of fluid therealong to operate said second function motor, and
- B. to block said second passageway to divert said hydraulic fluid from said second motor.
- 2. A fluid circuit including:
- first and second fluid pumps;
- first and second fluid motors;
- a first fluid path for delivering fluid from said first pump to said first motor, said first path including a first function control valve;
- a second fluid path for delivering fluid from said second pump to said second motor;
- speed selector means in said second path for selectively diverting fluid from said second pump into said first path;
- a third path open from said first function control valve to said second path;
- said first function control valve being selectively operable:
- A. to form a part of said first path to pass fluid therein to said first motor, and
- B. to divert fluid in said first path into said third path;
- second function control valve means in said second path selectively operable:
- A. to form a part of said second path to pass fluid therein to said second motor, and
- B. to divert fluid in said second path from said second motor.
- 3. The fluid circuit of claim 2 and one way valve at the junction of said third path and said second path for preventing flow of fluid from said second path along said third path when there is no flow of fluid from said first function control valve into said third path.
- 4. The circuit of claim 3 and unloading means in said second path for diverting the flow of fluid from said second pump away from said second motor responsive to the presence of at least a predetermined pressure in said third path.
- 5. The circuit of claim 4 and means for preventing reverse flow in said second path past said unloading means.
- 6. The circuit of claim 4 wherein said fluid is hydraulic liquid;
- a reservoir for storing said liquid; and wherein said circuit is comprised of a plurality of closed loops, at least some of which include said reservoir, intake conduits from said reservoir to said pumps, and conduits from said unloading means and said first and second function valves and opening to said reservoir.
- 7. A backhoe excavator having right and left crawler tracks, and a driveable boom, stick and bucket, said excavator including two circuits as set out in claim 6, said first function motors each driving one of said tracks, and said second function motors each driving at least one of said boom, stick and bucket.
- 8. A fluid circuit for selectively performing a first function at a first slower speed, at a second higher speed and not performing that function; and selectively for performing or not performing a second function, said circuit including:
- a first fluid pump;
- a first function motor;
- a first fluid path from said pump to said motor to carry fluid to drive said motor;
- said first path including a first function control valve;
- a second fluid pump;
- a second function motor;
- a second fluid path from said second pump to said second function motor to carry fluid to drive said second motor;
- said second path including in order from said second pump toward said second motor;
- a first function speed selector valve,
- an unloading valve, and
- a second function control valve;
- said speed selector valve being selectively operable:
- A. to form a part of said second path, and
- B. to block flow in said second path and to divert it to said first path to augment the output from said first pump to said first function control valve;
- said first function control valve being selectively operable:
- A. to form a part of said first path to permit fluid therein to pass to said first function motor to perform said first function, and
- B. to block flow in said first path to said first function motor and divert it to a first function control valve outlet line;
- said first function control valve outlet line opening to a one way check valve;
- said check valve opening to said second path between said unloading valve and said second function control valve;
- there being a pressure control line open from said first function control valve outlet passageway to said unloading valve;
- said unloading valve being operable responsive to the presence of a predetermined pressure in said pressure control line to divert flow of fluid from said second pump away from said second path;
- said second function control valve being selectively operable:
- A. to form a part of the second path to permit the passage of fluid therealong to operate said said function motor, and
- B. to block said second passageway to divert said hydraulic fluid from said second motor.
- 9. The circuit of claim 3 and unloading means in said second path for diverting the flow of fluid from said second pump away from said second motor responsive to the presence of at least a predetermined pressure in said third path.
- 10. The circuit of claim 1 wherein said first and second hydraulic pumps are of a fixed displacement type.
- 11. The fluid circuit of claim 1 wherein said first pump is a pressure compensated, variable displacement pump.
- 12. The hydraulic circuit of claim 11 wherein said first pump is pressure compensated in such a manner as to drastically limit its volumetric displacement only at a point where slightly less than the maximum allowable system pressure is achieved in the output of the pump.
- 13. In combination with a backhoe excavator having right and left crawler tracks, a driveable boom, stick and bucket, a first function motor for driving a first of said tracks, separate function motors for driving each of said boom, stick and bucket, and means for driving a second of said tracks; a hydraulic circuit including:
- a first hydraulic pump;
- said first track function motor;
- a first hydraulic path from said pump to said motor to carry fluid to drive said motor;
- said first path including a first track function control valve;
- a second hydraulic pump;
- at least one second function motor for driving one of said boom, stick and bucket;
- a second hydraulic path from said second pump to said second function motor to carry fluid to drive said second motor;
- said second path including in order from said second pump toward said second motor:
- a first function speed selector valve,
- an unloading valve, and
- a second function control valve;
- said speed selector valve being selectively operable:
- A. to form a part of said second path, and
- B. to block flow in said second path to divert it to said first path to augment the output from said first pump to said first function traction control valve;
- said first function control valve being selectively operable:
- A. to form a part of said first path to permit fluid therein to pass to said first function motor to perform said first function, and
- B. to block flow in said first path to said first function motor and to divert it to a first function control valve outlet line;
- said first function control valve outlet line opening to a one way check valve;
- said check valve opening to said second path between said unloading valve and said second function control valve;
- there being a pressure control line open from said first function control valve outlet passageway to said unloading valve;
- said unloading valve being operable responsive to the presence of at least a predetermined pressure in said pressure control line to divert flow from said second motor away from said second path; and
- said second function control valve being selectively operable:
- A. to form a part of the second path to permit the passage of fluid therealong to operate said second function motor, and
- B. to block said second passageay to divert said hydraulic fluid from said second motor.
- 14. The hydraulic circuit of claim 13 wherein said first and second hydraulic pumps are of a fixed displacement type.
- 15. The hydraulic circuit of claim 15 wherein said first pump is a pressure compensated, variable displacement pump.
- 16. The hydraulic circuit of claim 15 wherein said first pump is pressure compensated in such a manner as to drastically limit its volumetric displacement only at a point where slightly less than the maximum allowable system pressure is achieved in the output of the pump.
CROSS-REFERENCE TO RELATED APPLICATION:
This application is a continuation-in-part of my application Ser. No. 293,819, filed Oct. 2, 1972, now abandoned.
US Referenced Citations (5)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
293819 |
Oct 1972 |
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