Proportioning brake control device with bypass

A device for a dual brake system including a master cylinder and front and rear brake actuators,

• said device being located in said system between said master cylinder and said rear brake actuator and including,
• a housing having a fluid inlet adapted to receive fluid from said master cylinder and a fluid outlet through which fluid is adapted to be displaced to said rear brake actuator,
• a first modulating valve assembly having an inlet communicable with said fluid inlet and an outlet communicable with said fluid outlet,
• said first valve assembly being adapted for movement in response to fluid pressure at said fluid inlet for decreasing the transmission of fluid pressure from said fluid inlet to said fluid outlet,
• a second modulating valve assembly having a valve member with a first area exposed to the fluid pressure at said outlet of said first valve assembly and a second area exposed to the fluid pressure at the inlet of said first valve assembly,
• means defining a first flow path from said fluid inlet to the inlet of said first valve assembly and from the outlet of said first valve assembly through said second valve assembly and finally from said second valve assembly to said fluid outlet,
• said valve member of said second modulating valve assembly being actuatable in response to a predetermined fluid pressure differential between said inlet and outlet of said first valve assembly to provide a second flow path at least partially different from said first flow path for communicating fluid directly from said fluid inlet to said fluid outlet, and
• bypass means for sensing a predetermined pressure condition in an ancillary brake system for providing a direct flow path from said fluid inlet to said fluid outlet and bypassing said first and second valve assemblies.

A device for a dual brake system including a master cylinder and front and rear brake actuators,

• said device being located in said system between said master cylinder and said rear brake actuator and including,
• a housing having a central longitudinal bore and a second bore different from said central bore,
• said housing having a fluid inlet and a fluid outlet, said inlet adapted to receive fluid from said master cylinder and being communicable with one portion of said central bore, and said outlet adapted to displace fluid to said rear brake actuator and being communicable with a second portion of said central bore,
• first proportioning valve means actuatable in response to fluid pressure at said inlet in excess of a first predetermined pressure for decreasing the transmission of fluid pressure from said inlet to said outlet,
• said first proportioning valve means being disposed in said second bore and being movable longitudinally therein,
• second proportioning valve means being disposed in said central bore and being movable longitudinally therein,
• means defining a first flow path from said fluid inlet to the inlet of the first proportioning valve means and from the outlet of said first proportioning valve means through at least part of said second proportioning valve means and finally to said fluid outlet,
• said second proportioning valve means actuatable in response to a predetermined pressure differential between said inlet and said outlet to provide a second flow path at least partially different from said first flow path and circumventing said first proportioning valve means and permitting fluid to flow directly from said inlet to said outlet,
• bypass means for sensing a predetermined pressure condition in an ancillary brake system for providing a direct flow path from said fluid inlet to said fluid outlet and bypassing said first and second proportioning valve means, and
• said bypass means being disposed in said central bore and being movable longitudinally therein in substantial coaxial relationship with said second proportioning valve means.