Liquid pressure control device for anti-lock brake system

Claim 1

A liquid pressure control device for an anti-lock brake system, comprising: (a) control valve means intermittently interrupting the liquid pressure feed from master cylinder means to wheel cylinder means; (b) a liquid pressure control piston which shifts to control the liquid pressure to the said wheel cylinder means; (c) a differential pressure-responding member which causes the closing action of the said control valve means and the movement of the said liquid pressure control piston, in response to forward motion of the differential pressure-responding member; (d) a gas pressure chamber charged with gas which returns the said differential pressure-responding member to its initial position during the non-braking and normal braking condition; (e) a liquid chamber, wherein the controlling liquid pressure acts against the gas pressure in the said gas pressure chamber during the anti-lock action, so as to make the said differential pressure-responding member move forwards; (f) on-off valve means which inputs the controlling liquid pressure into the liquid chamber during the anti-lock action and dissipates the controlling liquid pressure in the liquid chamber during the non-braking and normal braking condition; (g) a stopper arranged engageably to the said differential pressure-responding member located in its initial position; and (h) engagement control means, which maintains the differential pressure-responding member in its initial position by causing the stopper to engage with the differential pressure-responding member during non-braking and normal braking condition and disengages the stopper from the differential pressure-responding member during anti-lock action so as to allow the latter to have forward motion.