Caliper disc brake or the like

Apparatus for controlling torque applied to a rotor mounted for rotation comprising:

• friction means on each side of the rotor;
• means mounting each of said friction means for movement relative to said rotor between a position engaging said rotor and a release position disengaged from said rotor by a gap of predetermined size;
• resilient means operatively connected to said friction means for applying a force sufficient to urge said friction means into one of said positions;
• a main piston and cylinder assembly for moving said friction means to the other of said positions when a predetermined volume of headspace fluid is forced into said cylinder under a pressure sufficient to overcome the resilient force;
• and power means operatively connected to said main piston and cylinder assembly for applying said predetermined volume of fluid to said main piston assembly during each pressure applying actuation of said assembly regardless of variations in the headspace capacity of said main piston and cylinder assembly;
• said power means including a master cylinder unit comprising a cylinder chamber communicating with said main piston and cylinder assembly, a plunger mounted for reciprocation in said chamber, a hydraulic reservoir communicating with said cylinder through passage defining means, means connected to said plunger for reciprocating said plunger within said chamber through a predetermined stroke between a position permitting flow of fluid between said reservoir and said chamber and a position preventing flow between said reservoir and said chamber, means for establishing a fluid seal between said chamber and said plunger at a point in said pressure applying stroke which occurs after flow communication between said chamber and said reservoir has been blocked for thereafter pumping said predetermined volume of high pressure fluid into said main piston and cylinder means, piston means in said reservoir, and means urging said piston means against the hydraulic fluid in said reservoir thereby permitting said reservoir to be positioned in a plurality of different attitudes.

A disc brake for applying a torque resisting force to a rotatable shaft having a disc brake rotor thereon comprising:

• rotation resisting friction means on each side of said rotor;
• means mounting each of said friction means for movement between a position engaging said rotor and a position disengaged from said rotor by a gap of predetermined size, resilient means operatively connected to said friction means to urge said friction means into torque resisting engagement with said rotor;
• hydraulic brake piston and cylinder means operatively connected to said friction means for moving said friction means to said disengaged position;
• a master cylinder including a cylinder wall defining a cylinder chamber, conduit means connecting said chamber to said brake cylinder, a plunger mounted for reciprocable movement in said master cylinder through a predetermined stroke, a fluid reservoir, passage defining means solely within said cylindrical wall communicating with said chamber when said plunger is in a fully extended brake engaging position;
• power means for moving said plunger in a fluid pumping stroke in said chamber from a fully extended to a retracted position to first block said passage thereby sealing said reservoir from said chamber and for thereafter pumping a predetermined volume of hydraulic fluid from said chamber into said brake cylinder for moving each of said friction means to said disengaged position spaced from the rotor by said gap.

In a brake system or the like, wear compensating apparatus for maintaining a predetermined gap between the planar friction surfaces of relatively movable friction elements when the elements are in their released position comprising;

• means for moving at least one of said elements relative to the other in a direction parallel to said planar surfaces;
• resilient means for normally urging said friction elements into engagement with each other for terminating said parallel relative movement between said friction elements;
• hydraulic piston and cylinder means operatively connected to said friction elements for overcoming said resilient means and moving said elements through said predetermined gap to said released position, said piston and cylinder means having a headspace which gradually reduces in volume in response to wear of said friction elements, power means for directing a predetermined volume of hydraulic fluid into said hydraulic piston and cylinder means during each movement of said friction element to said released position, said power means including a master cylinder having a cylinder wall defining a cylinder chamber and a plunger mounted for reciprocable movement in said cylinder chamber, a hydraulic reservoir, and passage defining means disposed solely within said cylinder walls, said power means also including means for moving said plunger between a position out of engagement with said passage defining means for receiving any excess hydraulic fluid from said diminishing headspace that is due to frictional wear of said elements and a position closing said conduit means and thereafter directing said predetermined volume of hydraulic fluid into said hydraulic piston and cylinder means for moving the elements to their released positions.

In a brake system or the like, wear compensating apparatus for maintaining a predetermined gap between the planar friction surfaces of relatively movable friction elements when the elements are in their released positions comprising;

• means for moving at least one of said elements relative to the other in a direction parallel to said planar surfaces;
• pressure applying means for normally urging said friction elements into engagement with each other for terminating said parallel relative movement between said friction elements, hydraulic piston and cylinder means operatively connected to said friction elements for overcoming said pressure applying means and moving said elements through said predetermined gap to said released position, said piston and cylinder means having a headspace which gradually reduces in volume in response to wear of said friction elements, means for directing a predetermined volume of hydraulic fluid into said hydraulic piston and cylinder means during each movement of said friction element to said released position, and reservoir means for receiving any excess hydraulic fluid from said diminishing headspace that is due to frictional wear of said elements prior to moving the elements to their released positions, piston means in said reservoir, and means urging said piston means against the hydraulic fluid in said reservoir thereby permitting said reservoir to be positioned in a plurality of different attitudes.