Back to results
US 4,486,152 AGranted
Pump with spring loaded valve
AssigneeHydro Rene Leduc
InventorLouis-Claude Porel
Life of this patent
Estimating the term…
Abstract
A hydraulic pump having spring loaded valves utilizes a spring providing a constant spring force and a spring providing a varying spring force. The varying spring force depending upon the position of the pump piston. The pump suction valve opens after a variable delay relative to the beginning of the piston suction phase when the pressure prevailing in the pump's dead chamber falls below a predetermined value. Abrupt decompression to the dead chamber is therefore avoided resulting in reduced energy consumption and noise level.
Claims8
A hydraulic pump comprising:
- at least one moveable piston means;
- means for moving said piston means;
- suction valve means in communication with said piston for permitting flow of hydraulic fluid into said pump during a suction phase of said piston movement;
- delivery valve means in communication with each of said piston means, for permitting the flow of hydraulic fluid out of said pump during a compression phase of said piston movement;
- first spring coupled to said suction valve for providing a first substantially constant force urging said suction valve closed;
- a moveable cam;
- shaft means coupled to said piston moving means and coupled to said cam for moving said cam in synchronism with the cycle of said pump;
- second spring bearing against said cam and opposing said first spring coupled to said suction valve for providing in a direction opposite to said first force a counterforce from said second spring varying in synchronism with said pump cycle, said counterforce being smaller than said first force during said pump delivery phase and higher than said first force during at least part of said suction phase, said valve opening only when pump residual pressure has fallen below a predetermined value.
5 more elements
Dependencies are inferred from the claim text.