Dual fluid supply circuit for a power steering and a hydraulic power brake

Claim 2

A dual fluid supply circuit for a fluid recirculating mechanism having a fluid inlet and outlet, comprising, a main normally driven pump and an auxiliary normally at rest pump each having a fluid discharge and return line, means connecting said discharge lines to said inlet, and said return lines to said outlet of said mechanism, first control means in said lines blocking the flow of fluid between said pumps, and means including flow sensing means, in said main pump''s discharge line, being operably connected to said auxiliary pump, for automatically activating said auxiliary pump in response to a predetermined decay in the fluid flow discharge of said main pump.

Claim 3

A dual fluid supply circuit as in claim 1, said flow sensing means comprising; a switch housing defining a fluid flow passage, a first, flexible, electrically conductive member supported by said switch housing at one end, and having its other end exposed to a fluid flow passing through said fluid flow passage, said flexible member making and breaking an electrical contact with a second electrically conductive member in response to variations of said fluid flow.

Claim 4

A dual fluid supply circuit as in claim 1 where said first control means comprise a shuttle valve.

Claim 5

A dual fluid supply circuit as in claim 1 where said first control means comprise a plurality of check valves.

Claim 6

A fluid supply circuit as in claim 1, said first control means comprising a check valve in said discharge line of said auxiliary pump, and a flow switch-check valve combination in the discharge line of said main pump, said flow switch-check valve combination which also serve as said flow sensing means, comprising; a switch housing defining a fluid flow passage, said fluid flow passage containing a sealing element for allowing flow through said fluid flow passage in one direction only, said sealing element causing making or breaking an electrical coNtact in response to the flow rate through said fluid flow passage.

Claim 7

A dual fluid supply circuit as in claim 1 where said fluid recirculating mechanism is a hydraulic power brake.

Claim 8

A dual fluid supply circuit as in claim 1 where said fluid recirculating mechanism is a power steering.

Claim 9

A dual fluid supply circuit for a hydraulic power brake and a power steering comprising; a main, normally driven pump for normally supplying fluid to said hydraulic power brake and said power steering, an auxiliary normally at rest pump for supplying fluid to said hydraulic power brake and said power steering upon failure of said main pump, lines for hydraulically connecting said main and auxiliary pumps to said hydraulic power brake and said power steering, first control means in said lines blocking the flow of fluid between said pumps, and means including flow sensing means, in said discharge line of said main pump operably connected to said auxiliary pump, for automatically activating said auxiliary pump in response to a predetermined decay in the flow discharged by said main pump.

Claim 10

A dual fluid supply circuit for a hydraulic power brake and a power steering comprising; a main, normally driven pump for normally supplying fluid to said hydraulic power brake and said power steering, an auxiliary normally at rest pump for supplying fluid to said hydraulic power brake and said power steering upon failure of said main pump, lines for hydraulically connecting said main and auxiliary pumps to said hydraulic power brake and said power steering, first control means in said lines blocking the flow of fluid between said pumps, and means including flow sensing means, in said discharge line of said main pump operably connected to said auxiliary pump, for automatically activating said auxiliary pump in response to a predetermined decay in the flow discharged by said main pump.