Vehicle brake indicator system

Claim 1

An automotive alarm circuit comprising a first brake switch (10) closable in response to depression of a brake pedal: a lamp alarm system (40R, 40L) at the rear end of a vehicle; a second switch (12) responsive to vehicle deceleration associated with an abnormally high rate of depression of the brake pedal; a flasher 36; and circuit connections between the lamp alarm system and the flasher and the switches, whereby the lamp alarm system provides the following vehicle with one visible signal when the brake pedal is lightly depressed, and a second visible signal when the brake pedal is depressed at an abnormally high rate; said flasher and said second switch being in electrical parallelism with one another; said flasher and said second switch being in series between the first brake switch and said lamp system, whereby the flasher controls the lamp system when the second switch is open, and the second switch controls the lamp system when the second switch is closed; said second switch being a liquid pressure-responsive switch having an operating connection with the vehicle brake line, whereby a step increase in brake line pressure is required to operate said second switch; said second switch comprising a cup-shaped housing (18) having an end wall and an open mouth portion, with said mouth portion being sealably connected to the brake line, a piston (14) slidably mounted within said housing for movement toward or away from the brake line, a compression coil spring (24) biasing said piston toward the brake line, and two deflectable switch arms (25, 26) extending through the end wall of the housing into the space circumscribed by the coil spring; said piston being aligned with said switch arms to deflect said arms when the piston is moved away from the brake line.