Lucas Industries Public Limited Company

Lucas Industries Limited

Lucas Limited Public Limited Company

Lucas Industries Limited Company

Lucas Ind. Public Limited Co.

Roy Campbell

Anthony G Price

Andrew P Green

David Parry

Desmond H Reynolds

Graham J Gornall

Klaus Hillen

Sigma Micke

Eric Henson

Robert R Bishop

A compound disc brake comprises a pair of pressure plates with a ball and ramp camming mechanism, one of the plates comprises a driven plate keyed to a rotating axle shaft to be braked, and the other plate comprises an input plate carried from the driven plate by the camming mechanism. The input plate is of larger diameter than the driven plate with its radially outer region comprising a torque-transmitting mechanism which transmits torque applied to that region by primary braking device, which can be a spot brake, to the central region of the input plate. Retardation of the input plate by the primary braking device causes the pressure plates to separate axially and move into engagement with relatively stationary braking surfaces in a brake housing whereafter servo braking occurs. Various multi-plate embodiments are disclosed, including embodiments in which the torque-transmitting mechanism is a separate annular disc keyed to the outer peripheral edge of the servo plate. Other modifications of the pressure plates are also disclosed.

Self-energizing disc brakes

A rotatable member for a brake of the liquid cooled type comprises a disc provided on opposite sides with annular braking faces. The disc incorporates a plurality of angularly spaced liquid supply slots which extend through the material of the disc and radially outwards from a position inwardly of the inner peripheral edges of the braking faces. A portion at the inner end of each slot is of a circumferential length greater than the remainder of the slot. The member may comprise a braking member for the brake, or it may be separate from the brake and act as a pump member in the form of a turbo disc.

Vehicle disc brakes of the liquid cooled type

A pressure cylinder has a piston actuated by a force-input rod. An enlarged head of the rod is engaged by a washer and the assembly retained within the cylinder by a cup-shaped retainer press-fitted into the cylinder open end. An outer surface of the retainer is flush with the adjacent axially outermost surface of the cylinder and engages a support, to which the cylinder is fixed, in order to transmit to the support retraction forces sustained by the rod.

Pressure cylinder

A braking member for a brake of the liquid cooled type is provided on at least one side with an annular reservoir for cooling liquid, and passages are arranged to control the release of liquid from the reservoir to braking surfaces in response to centrifugal force.

A brake of the self-energising liquid cooled type incorporates a pump mechanism for pumping liquid from a sump to a braking member which is slidably keyed to a shaft to be braked. The pump mechanism incorporates one rotatable pump member which is driven from the shaft and may be housed within a pressure plate which forms a part of an actuating mechanism for the brake. Alternatively the pump may comprise a turbo-disc which is separate from the brake and is spaced from the stack of braking members.

In a self-energizing disc brake of the spreading type the actuator mechanism incorporates a restrictor in the form of a circumferentially extending discontinuous oil-seal which co-operates with radial faces on the two pressure plates. A secondary, or elevated, reservoir for liquid is therefore defined between said pressure plates by said oil-seal. Liquid can escape from this reservoir in order to enhance the cooling of the braking surfaces, defined by engagement of rotatable friction discs with end faces of a housing, pressure plates and a planar non-rotatable disc. In the brake shown in FIG. 6 two annular members act as seals on the ends of the outermost friction discs.

A piston and cylinder assembly for a vehicle hydraulic system has a retaining device comprising an insert acting between a piston and the cylinder bore in which it works, the insert having a releasable frictional engagement in the bore and acting as an abutment to hold the piston in its retracted position to maintain the effective length of the assembly at a predetermined value for installation, until the assembly is operated hydraulically. The assembly may be an actuator for a self-energizing disc brake, or a slave cylinder for a vehicle clutch system.

Hydraulic piston and cylinder assemblies

In a self-energizing disc brake of the spreading type, an intermediate metal plate located between the friction linings on an adjacent pair of rotatable friction discs includes portions which project radially with respect to the linings, and the portions include slots which define fins to facilitate cooling.

A self-energizing disc brake of the spreading type is disclosed. In the disc brake rotatable friction discs provided on opposite sides with linings are adapted to be brought into engagement with radial braking surfaces in a housing by an actuator assembly. The actuator assembly comprises pressure plates located between the discs and centered by pilot lugs, and balls located in oppositely inclined recesses in the adjacent faces of the pressure plates. At least the linings which engage with the pressure plates are separated into annular rings by an annular groove, and the groove is substantially coincident with a pitch circle of constant diameter upon which the recesses lie in an angularly spaced relationship. The groove increases the degree of cooling in the regions of the base of the recesses, thereby reducing the likelihood of hot spotting occurring in such regions.

Self energizing disc brakes

A disc brake of the spreading type is actuated by means of a 'Bowden' cable (20) which acts between radial lugs (25, 29) on the pressure plates (6, 7). The cable (20) is angled with respect to the plane of the plates (6, 7), preferably substantially to complement the helix motion of the balls or rollers (13) co-operating with the ramps in the recesses (14).

A self-energizing disc brake of the spreading type is adapted to be applied by a cable assembly. The cable assembly acts through a lever which is disposed in a plane lying between a pair of pressure plates in order to move the plates angularly in opposite directions.

Self-energizing disc brakes with cable assembly and cable casing therefor

In a disc brake of the spreading type, angular movement of the pressure plates to apply the brake is effected by a brake-applying member which co-operates with at least one of the balls comprising a rolling actuator body and located in complementary opposed recess in the two plates. The member may comprise a wedge disposed between a pair of balls and radially displaceable to separate the balls. Alternatively the balls may be received in openings in the inner ends of a pair of toggle links, or in a fitting or other member which can be withdrawn from the brake in a radial direction. In another construction a ball is received in an opening in a bell-crank lever of which one arm reacts against one of the pressure plates.

A spreading disc brake is actuated for parking or braking in an emergency by a brake-applying mechanism which comprises a pivotally mounted lever in the form of a bell-crank, and a pull-rod coupled to the lever. The inner end of the pull-rod is provided with an eye of which the inner side of the outermost end has a rocking and sliding engagement with a complementary arcuate face defining a notch in the innermost edge of the longer arm of the lever. The coupling between the pull-rod and the lever enables the pull-rod to adopt a substantially radial alignment with the brake center of rotation, even when brake lining wear progressively increases the brake forward to reverse articulation. The lever is pivotally mounted on one of the pressure plates by a pivot pin, and has a cranked nose which is received within the groove in the other pressure plate. In order to prevent the lever from twisting when the brake is applied, the lever reacts against reaction faces of which the face comprises a wall defining the outer side of the groove, and the face comprises a region on the pressure plate on the radially outermost side of the pin.

A self-energizing disc brake is disclosed. The brake is applied by moving a pair of pressure plates angularly to cause them to separate and clamp friction discs between themselves and braking faces at opposite ends of a housing. The angular movement of the plates is initiated by a brake-applying mechanism comprising a pair of links of different lengths, which are pivotally connected at their outer ends to respective lugs on the pressure plates, and a pull-rod which is connected to the inner ends of the links through a common pivot and is radially displaceable. This facilitates installations of the brake within asymmetrically arranged housings.

Self-energising disc brakes with links of different lengths

A pressure plate for a self-energizing disc brake of the spreading type is provided with angularly spaced integrally cast ears which project inwardly from the inner peripheral edge of the plate, and a recess or dimple is also cast integrally in each ear in the face of the ear adjacent to the braking face. A region of each ear outwardly of the recess or dimple defines an abutment face forming an anchorage for one end of an anchorage portion of a tension return spring with the recess or dimple accommodating the free end of the anchorage portion. In a modification each abutment face may be machined in the respective ear by turning down the ear over an arcuate area passing through the center of the recess or dimple and using the braking face as a datum.

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Worcestershire, United Kingdom

Roy Campbell