Brake pressure modulator

Claim 1

A pressure modulator for controlling the fluid pressure in a braking system comprising; a housing having an internal bore terminating in an enclosure; a plunger slidably mounted in said internal bore, said plunger having an operating end portion forming a brake fluid receiving chamber in said bore, said plunger being movable for varying fluid pressure in said chamber, said plunger forming a longitudinally extending bore terminating in a wall internally thereof and adjacent to said chamber; a diaphragm assembly reciprocably mounted in said enclosure; means for reciprocating said diaphragm assembly in response to the generation of control signals, and an operating rod coupled to said diaphragm assembly and having a free end portion, said operating rod being slidably received by said bore of said plunger for movement independently thereof with the free end portion thereof adapted to contact said wall for extending said plunger in a direction in said internal bore tending to increase said fluid pressure in said chamber and being movable in the opposite direction to separate from said wall for movement of said diaphragm assembly a greater distance than said operating end portion.

Claim 9

An apparatus for controlling the rate of application of fluid pressure in a brake system comprising; a housing having an internal bore terminating in an enclosure; a plunger slidably disposed within said bore and having an operating portion for controlling said fluid pressure; a diaphragm assembly reciprocably mounted in said enclosure and operatively coupled to said plunger for controlling the movement thereof in said bore; said diaphragm assembly partitioning said enclosure into first and second pressure chambers; means for reciprocating said diaphragm assembly in said enclosure in response to the generation of control signals, said reciprocating means including a vacuum source, means for normally communicating said first and second pressure chambers to said vacuum source and compound valve means for venting said first pressure chamber to ambient fluid pressure and interrupting communication between said first pressure chamber and said vacuum source in response to the generation of at least one of said control signals; an expansion chamber in fluid communication with said first pressure chamber; and a flow restricting member for providing fluid communication between said expansion chamber and said second pressure chamber, said flow restricting member having a flow orifice for providing a variable flow rate which decreases as the pressure differential across said member increases.

Claim 10

An apparatus for controlling the rate of application of fluid pressure in a brake system comprising; a housing having an internal bore terminating in an enclosure; a plunger slidably disposed within said bore and having an operating portion for controlling said fluid pressure; a diaphragm assembly reciprocably mounted in said enclosure and operatively coupled to said plunger for controlling the movement thereof in said bore; said diaphragm assembly partitioning said enclosure into first and second pressure chambers; means for reciprocating said diaphragm assembly in said enclosure in response to the generation of control signals, said reciprocating means including a vacuum source, means for normally communicating said first and second pressure chambers to said vacuum source and compound valve means for venting said first pressure chamber to ambient fluid pressure and interrupting communication between said first pressure chamber and said vacuum source in response to the generation of at least one of said control signals; an expansion chamber in fluid communication with said first pressure chamber; and a flow restricting member for providing fluid communication between said expansion chamber and said second pressure chamber, said flow restricting member having a flow orifice for providing a variable flow rate which decreases as the pressure differential across said member increases.