Brake booster
AssigneeLucas Industries Limited
InventorIvan Mortimer
Life of this patent
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Abstract
A brake booster having a fluid actuated piston in the form of a diaphragm (5) to which the supply of fluid is controlled by a valve mechanism (8A, 14A, 17), actuated by a driver-operated force input member (16) which acts via a reaction element (19) on an output member (10) providing power assisted input to a master cylinder. The booster includes a force transmission assembly (14,8) providing surfaces through which force is transmitted between the input and output members (16,10). A spring (24) is arranged to yield under a predetermined force to permit relative movement between parts (14) and (8) such as to change the ratio of the operative surface areas and thereby increase the boost ratio.
Claims17
A brake booster comprising a fluid-actuated servo piston to which the supply of working fluid is controlled by a valve mechanism actuated under the influence of a driver-operated force input member, the input member acting via a force transmission assembly on an output member arranged, in use, to provide power assisted input to a master cylinder, the force transmission assembly including a reaction element and providing surfaces through which force is transmitted between the input and output members and of which operative input and output areas define a boost ratio, and yieldable means arranged to yield under a predetermined transmitted force to permit movement of at least one part of the force transmission assembly in order to cause a change in the ratio of the operative surface areas in a manner to increase the boost ratio.
Dependencies are inferred from the claim text.