Panic stoplight system for automobiles using a fluid pressure switching device

A fluid pressure switching device in combination with a vehicle braking system for indicating panic braking, comprising:

• a fluid accumulator chamber, fluid supply means for supplying fluid to said accumulator chamber at variable rates for pressurizing said accumulator chamber, said fluid supply means including a fluid supply chamber communicating through a supply conduct with said accumulator chamber and volume reducing means for reducing the volume of said fluid supply chamber to force fluid therefrom into said accumulator chamber, a flow control check valve means in said supply conduit for preventing flow of fluid from said accumulator chamber to said fluid supply chamber, said vehicle braking system including a manually operated brake actuator and fluid conduit means through which pressure is applied by said brake actuator for applying the vehicle brakes, said brake actuator also being coupled via said fluid conduit means to supply pressure to said volume reducing means for operation of the latter in response to pressure in said fluid conduit means to reduce the volume of said fluid supply chamber for pressurizing said accumulator chamber at a rate proportional to the force applied to said brake actuator, a switch connected with signal lights of the vehicle, movable switch operating means responsive to a predetermined pressure in said accumulator chamber for operating said switch, a normally open bleed orifice in fluid communication with said accumulator chamber for passing fluid from the latter to relieve pressure therein at a predetermined rate, said orifice being of a size to preclude pressurization of said accumulator chamber in excess of such predetermined pressure when said fluid supply means supplies fluid to said accumulator chamber at or below such predetermined rate and to permit temporarily pressurization of said accumulator chamber in excess of such predetermined pressure when said fluid supply means supplies fluid to said accumulator chamber above such predetermined rate to effect movement of said switch operating means to operate said switch, the relationship of the size of said bleed orifice, the predetermined pressure at which said switch operating means operates said switch, and the fluid pressures in said fluid conduit means in response to operation of said brake actuator being such that said switch operating means is operative to operate said switch when said brake actuator has been operated for panic braking.