Brake linkage for vehicle friction brakes

Brake linkage for vehicle friction brake having an adjustable length vent play regulator (10) arranged between two brake linkage elements (4) and loaded by means of a brake power motor (6) with brake clamping force, said vent play regulator having adjustment means (17, 33, 34) for reducing vent play to the desired value and being driven by an auxiliary motor (14) when said desired value is exceeded, comprising

• (a) means for actuating said auxiliary motor (14) before said brake power motor (6) at the start of braking;
• (b) said auxiliary motor (14) changing the length of said vent play regulator (10) so as to diminish vent play upon its actuation through said adjustment means (17, 33, 34) until said friction brake is applied;
• (c) said brake power motor (6) subsequently upon its actuation tightly clamping said vehicle friction brake;
• (d) said auxiliary motor (14), at the end of braking upon decay of the actuation of said brake power motor (6), and upon decay of its own activation, readjusting the length of said vent play regulator (10) by means of said adjustment means (17, 33, 34) in the venting direction of said vehicle friction brake until the desired vent play is attained;
• (e) said adjustment means comprising a screw drive having as a first component a threaded spindle (17) and as a second component at least one nut (33, 34) in screw engagement therewith, one of said components being rotatably controlled by said auxiliary motor (14) by way of a one-way coupling (24) and being rotatably and axially power transmittingly articulated to one of said brake linkage elements, while the other of said components is non-rotatably controlled and is non-rotatably and axial power transmittingly articulated to the other of said brake linkage elements;
• (f) said auxiliary motor (14) engaging a turn lever (12) rotatably supported on said rotatably controlled component and coupled thereto by way of a first one-way coupling (24) blocking in the direction of brake applicaton and a first friction coupling (24) overlapping said first one-way coupling;
• (g) said rotatable component being coupled with an element (33) retained against rotation by way of a second one-way coupling (37) blocking brake venting in the direction of rotation of said rotatable component and by way of a second friction coupling (37) overlapping said second one-way coupling, and in series therewith by way of a play-containing rotational stop (41, 42), each of said friction couplings being stronger than the idling resistance in unlocking direction of the respective one-way coupling not overlapped thereby, said play (x) of said rotational stop (41, 42) corresponding to a pitch of said screw drive (17, 33, 34) which corresponds to the desired vent play;
• (h) said first one-way coupling and said first friction coupling sharing a first helical spring (24) wound to be substantially free of play, said turn lever (12) and said threaded spindle (17) having cylindrical surfaces (19, 22) on which said spring is seated to the extent of substantially at least one-half its length, said spring (24) being radially pre-stressed to abut against said cylinder surfaces, the winding direction of said spring being selected so as to cause an increase in its radial pressure against said cylinder surfaces (19, 22) upon rotation of said turn lever (12) in the direction of brake application.