Brake booster operated also by solenoid

Claim 1

A brake booster comprising: (a) a body with a large chamber and a small chamber linked to each other, (b) a power piston movably positioned in the large chamber so as to divide it into a control chamber and a vacuum chamber, (c) means for providing communication between said vacuum chamber and a vacuum source, (d) a hydraulic piston provided in said small chamber to divide it into an oil pressure control chamber and a high pressure chamber, said hydraulic piston operatively coupled to move with the power piston, (e) means for providing communication between said high pressure chamber which communicates with a fluid operated vehicle braking mechanism, (f) a relay valve cylinder with one end exposed to the atmosphere and the other end communicating with a source of vacuum, means to permit communication between the source of vacuum and the control chamber via a control pipe, (g) atmospheric air valve means and vaccum valve means provided in the relay valve cylinder and operable in response to brake operation to change the position of the cylinder vacuum valve means to permit communication between the control pipe and the vacuum chamber, each said valve means having valve seats, said relay valve cylinder including a valve piston connected to said atmospheric air valve means and said vacuum valve means, (h) relay valve piston means for linking the atmospheric air valve means and the vacuum valve means, (i) a solenoid having a movable solenoid plunger; and (j) lever means interconnecting said solenoid plunger and said relay valve piston means, said lever means pivotable about a fulcrum.