US 5,181,835 AGranted

Hydraulic pump

AssigneeCook Manufacturing Corporation

InventorGregory D. Cook

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Abstract

A hydraulic pump having a pump body formed by stacked plates mounted end-to-end. First and second ports for delivery and return of hydraulic fluid are formed through a port plate that is surmounted by a valve plate through which first and second main valve passages, each aligned with the first and second ports respectively, are formed. The valve plate is surmounted by a manifold plate in which first and second fluid distribution chambers, fluidly communicated with the first and second main valve passages respectively, are formed. A pump plate atop the manifold plate contains a gear assembly in a pumping chamber formed in the ends of the pump and manifold plates that draws fluid from one fluid distribution chamber and discharges it to the other. Each main valve passage contains a main pump valve that is biased for movement toward a sealing position that blocks fluid flow from through the main valve passage and each main pump valve is engaged by pistons in piston chambers that intersect the main valve passage in which the valve is disposed and opens to the fluid distribution chamber communicated with the other main valve passage.

Claims7

Dependent claims

A hydraulic pump, comprising:

a pump body wherein are formed first and second ports for delivery of hydraulic fluid from one port and return of hydraulic fluid to the other port, first and second fluid distribution chambers, and first and second main valve passages, the first main valve passage fluidly communicating the first fluid distribution chamber with the first port and the second main valve passage fluidly communicating the second fluid distribution chamber with the second port;
pumping means in the pump body operable for drawing hydraulic fluid from one fluid distribution chamber and discharging hydraulic fluid to the other fluid distribution chamber;
a first main pump valve disposed in the first main valve passage for movement to a sealing position wherein the first main pump valve seals the first main valve passage against fluid flow:
means for biasing the first main valve toward the sealing position thereof;
a second main pump valve disposed in the second main valve passage for movement to a sealing position wherein the first second pump valve seals the second main valve passage against fluid flow:
means for biasing the second main valve toward the sealing position thereof;
means fluidly communicated with the first fluid distribution chamber and responsive to fluid pressure therein for forcing the second main pump valve away from the sealing position thereof at such times that the pumping means is operated to draw hydraulic fluid from the second fluid distribution chamber and discharge hydraulic fluid into the first fluid distribution chamber;
and
means fluidly communicated with the second fluid distribution chamber and responsive to fluid pressure therein for forcing the first main pump valve away from the sealing position thereof at such times that the pumping means is operated to draw hydraulic fluid from the first fluid distribution chamber and discharge hydraulic fluid into the second fluid distribution chamber.

6 more elements

In a hydraulic pump of the type including a pump body wherein are formed first and second ports for delivering fluid from the pump from one of the first and second ports and receiving fluid returned to the pump at the other of the first and second ports, a plurality of chambers and passages containing pumping means for selectively forcing fluid into the first port while receiving fluid form the second port and alternatively forcing fluid into the first port while receiving fluid from the first port, and fluid control means for controlling the flow of fluid between the pumping means and the ports, the improvement wherein the pump body is comprised of a plurality of plates, each characterized as having a first end and an opposite second end, wherein said plates are connected end to end to form the pump body, wherein the chambers are formed in the ends of the plates, and wherein the ports and flow passages are formed through the plates to intersect the ends thereof.

Dependencies are inferred from the claim text.