Patent ID: 11958177
Assignee: MILWAUKEE ELECTRIC TOOL CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC B  F  H | IPC B  F  H

Claim 0:
1. A hydraulic pump, comprising:
a work port configured to couple to a fluid supply line of a hydraulic tool;
a high-flow piston configured to supply fluid along a first flow path to the work port;
a plurality of high-pressure pistons configured to supply the fluid along a second flow path to the work port; and
an unloading valve fluidly coupled to the first flow path and the second flow path, wherein the unloading valve is actuatable between an open state and a closed state, wherein the unloading valve is configured to permit the fluid to flow from the high-flow piston to the work port in the open state, wherein the unloading valve is configured to inhibit the fluid from flowing from the high-flow piston to the work port in the closed state, wherein the unloading valve is configured to actuate from the open state to the closed state when a pressure level of the fluid in the second flow path exceeds a first threshold pressure,
wherein the unloading valve comprises:
a first chamber fluidly coupled to the first flow path;
a movable ball disposed in the first chamber;
a second chamber comprising a plunger configured to move the movable ball from a seated position to an unseated position, wherein the second chamber is fluidly coupled to a hydraulic fluid tank, and wherein the plunger is configured to be subjected to the fluid in the second flow path; and
a spring in the first chamber and biasing the movable ball toward the seated position at which the movable ball is configured to block fluid communication between the first chamber and the second chamber,
wherein when the pressure level of the fluid in the second flow path exceeds the first threshold pressure, the plunger applies a force to the movable ball that overcomes a biasing force of the spring and moves the movable ball to the unseated position, and
wherein when the movable ball is in the unseated position, the first chamber is fluidly coupled to the hydraulic fluid tank via the second chamber.