초록 ▼

Disclosed herein is a fluid control system for varying the power available to a fluid powered tool, a hydraulically driven impact wrench. The system disclosed herein varies power available to the tool by use of a bypass mechanism that is downstream of a directional control valve spool. Among other t

Disclosed herein is a fluid control system for varying the power available to a fluid powered tool, a hydraulically driven impact wrench. The system disclosed herein varies power available to the tool by use of a bypass mechanism that is downstream of a directional control valve spool. Among other things, the advantageous placement of the bypass valve limits the thermal burden in the hydraulic circuit.

대표청구항 ▼

1. A power limiting system for a fluid driven tool, the power limiting system disposed upstream of a work unit and within the tool, the power limiting system comprising:an inlet port for receiving an inlet flow comprising fluid from a supply; a direction control valve downstream of the inlet port fo

1. A power limiting system for a fluid driven tool, the power limiting system disposed upstream of a work unit and within the tool, the power limiting system comprising:an inlet port for receiving an inlet flow comprising fluid from a supply; a direction control valve downstream of the inlet port for controlling the flow to the work unit; a bypass valve which is disposed downstream of the direction control valve; and a motor reversing valve disposed downstream of the direction control valve and upstream of the bypass valve, wherein the bypass valve comprises a movable bypass member with a valveless conduit, wherein the valveless conduit is adapted for diverting a portion of the inlet flow from entering the work unit directly to a return flow from the work unit, wherein the bypass valve is movable about an axis generally orthogonal to an axis of movement of the motor reversing valve. 2. A power limiting system as in claim 1, wherein the motor reversing valve is adapted for redirecting the inlet flow to a reversing circuit to cause reverse operation of the work unit.3. A power limiting system as in claim 2, wherein the motor reversing valve is reconfigured by lateral movement thereof.4. A power limiting system as in claim 1, wherein the movable bypass member diverts the portion of the inlet flow upon rotation of the bypass valve.5. A power limiting system as in claim 1, wherein the work unit comprises a gerotor motor.6. A power limiting system as in claim 1, wherein the work unit comprises a gear driven motor.7. A power limiting system as in claim 1, wherein the portion of the inlet flow is about fifty percent of the inlet flow.8. A power limiting system as in claim 1, wherein the portion of the inlet flow is about zero percent of inlet flow.9. A power limiting system as in claim 1, wherein the portion of the inlet flow ranges from about zero percent to about one hundred percent of the inlet flow.10. A power limiting system as in claim 1, wherein the direction control valve is adapted for operating in the idle state to interrupt the inlet flow to the work unit.11. A power limiting system as in claim 1, wherein the direction control valve is adapted for operating in the idle state to divert the inlet flow from the work unit.12. A hydraulically driven tool comprising:a work unit within the tool for completing work; a fluid control system disposed within the tool upstream of the work unit, the fluid control system comprising an inlet port for receiving a flow comprising hydraulic fluid from a supply, a direction control valve downstream of the inlet port for controlling the flow to the work unit, a bypass valve which is disposed downstream of the direction control valve, and a motor reversing valve disposed downstream of the direction control valve and upstream of the bypass valve, wherein the bypass valve comprises a bypass adapted for diverting a portion of the flow from entering the work unit, wherein the bypass valve is movable about an axis generally orthogonal to an axis of movement of the motor reversing valve; and, an outlet for returning the hydraulic fluid to the supply. 13. A hydraulically driven tool as in claim 12, wherein the tool comprises a variable torque impact wrench.14. A hydraulically driven tool as in claim 12, wherein the tool comprises a wrench.15. A hydraulically driven tool as in claim 12, wherein the tool comprises a grinder.16. A hydraulically driven tool as in claim 12, wherein the tool comprises a drill.17. A hydraulically driven tool comprising:a work unit comprising a gerotor motor; a fluid control system operably coupled to the work unit, the fluid control system comprising an inlet port for receiving a flow comprising hydraulic fluid from a supply, a direction control valve downstream of the inlet port for controlling the flow to the work unit, a bypass valve which is disposed downstream of the direction control valve, and a motor reversing valve disposed downstream of the direction control valve, wherein the bypass valve comprises a rotatable valveless bypass member having a bypass hole adapted for diverting a portion of the flow from entering the work unit directly into a return flow from the work unit, wherein the bypass valve is movable about an axis generally orthogonal to an axis of movement of the motor reversing valve; and an outlet for returning the hydraulic fluid to the supply.