US 5,470,137 AGranted

Copy valve for an anti-lock brake system

AssigneeKelsey-Hayes Company

InventorsPeter Every, Gerald Sivulka, Edward M. Fuller

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Abstract

A copy valve for an anti-lock brake system. The copy valve has a housing enclosing four chambers. A first and fourth chamber of the enclosed four chambers receives pressurized fluid directly from the first and second cylinders of a dual master brake cylinder. The third chamber receives the pressure of the controlled brake actuator while the second chamber is connectable to the uncontrolled brake actuator. In one embodiment, a single piston is enclosed in the housing and the first and second chambers are disposed at the opposite ends of the piston. The piston has an enlarged collar intermediate the two ends which is received in an annular recess provided in the housing. The third chamber is formed between a first face of the piston's enlarged collar and the annular recesses while the fourth chamber is formed between the opposite face of the piston's enlarged collar and the adjacent face of the housing. A throughbore is provided through the piston connecting the first and second chambers. A valve disposed in the throughbore is open when the piston is in the second chamber and closed when the piston is displaced from the second chamber.

Claims10

Dependent claims

A copy valve comprising:

a housing having four internal chambers;
a first input port provided through said housing for transmitting a first pressurized fluid received from a first external source to a first of said four internal chambers;
an output port provided through said housing for transmitting a second pressurized fluid from a second of said four internal chambers external to said housing;
a second input port provided through said housing for transmitting a third pressurized fluid received from a second external source to a third of said four internal chambers;
a third input port provided through said housing for transmitting a fourth pressurized fluid received from a third external source to a fourth of said four internal chambers;
and
means responsive to the pressure of said first, second and third pressurized fluids being substantially equal for providing an unobstructed fluid path between said first chamber and said second chamber, said means further responsive to the pressure of said third pressurized fluid in said third chamber being less than the pressure of said first and fourth pressurized fluids for blocking said unobstructed path between said first and second chambers and reducing the pressure in said second chamber to be substantially equal to the pressure in said third chamber, and further responsive to the pressure of said fourth pressurized fluid being less than the pressure of said first pressurized fluid, independent of the pressure of said third pressurized fluid to provide an unobstructed fluid path between said first and second chambers.

4 more elements

A copy valve in an anti-lock brake system for an automotive vehicle, said anti-lock brake system having a dual master brake cylinder, and an electronic control controlling the fluid pressure applied to a brake actuator associated with one of the rear wheels of the vehicle, said copy valve comprising:

a housing having four internal chambers;
a first port associated with a first of said four internal chambers, said first inlet port connectable to one cylinder of said dual master brake cylinder;
a second port associated with a second of said four internal chambers, said outlet port connectable to a brake actuator of a brake actuator associated with said second wheel of said vehicle;
a third port associated with a third of said four internal chambers, said third port connectable to the brake actuator associated with said one of said rear wheels of said vehicle;
a fourth port associated with a fourth of said four internal chambers, said fourth port connectable to a second cylinder of said dual master cylinder;
a first piston disposed in said third chamber displaceable from a second position to a first position in response to receiving a pressurized fluid through said third port and displaceable from said first position to said second position in response to the pressure of a fluid received through said first port being greater than the pressure of a fluid received into said second chamber through said second port;
a valve attached to said first piston having an open state permitting a fluid flow from said first chamber to said third chamber when said first piston is in said first position, and a closed state prohibiting a fluid flow from said first chamber to said third chamber in response to said piston being displaced from said first position;
a fluid passageway connecting said third chamber to said fourth chamber;
a second piston disposed in said fourth chamber displaceable from a second position to a first position in response to receiving a fluid pressure on one side of said second piston being substantially equal to the fluid pressure on the reverse side of said second piston and displaceable from said first position to said second position in response to said fluid pressure on one side of said second piston being less than said fluid pressure on said reverse side;
and
a dual valve attached to said second piston, said dual valve prohibiting a fluid flow from said first chamber to said second chamber and permitting a fluid flow from said fourth chamber to said second chamber when said second piston is in said first position and permitting a fluid flow from said first chamber to said second chamber and prohibiting a fluid flow from said chamber to said second chamber when said second piston is in its second position.

8 more elements

Dependencies are inferred from the claim text.