Abstract: A vacuum servo brake has an input member by which a valve arrangement may be acted upon at an input force to connect a working chamber selectively to the outside or to a vacuum chamber (separated from the working chamber by a piston which may be brought into operative connection with a main cylinder via an output member to generate a braking pressure). Provided on the piston is an elastomeric reaction member through which a reaction force may be applied to the input member. The output member has a stop which, with a predetermined input force, abuts against the working piston to alter an amplification ratio of the brake. Arranged adjacent to the reaction member is at least one volume take-up means into which part of the reaction member may be displaced in the event of the vacuum servo brake being actuated. Furthermore, the stop is preferably of resilient construction.

Abstract: A switch adapted to be positioned on the pushrod of a hydraulic cylinder assembly and including a housing adapted to be positioned against an end of the hydraulic cylinder assembly and including a plurality of axially spaced electrical contacts, and a plunger mounted for axial sliding movement in the housing and adapted to be fitted over the pushrod with a driving connection between the pushrod and the plunger whereby the plunger is moved slidably forwardly in the housing in response to forward movement of the pushrod for selective coaction between the contacts to selectively generate a plurality of control signals. The driving connection between the plunger and the pushrod includes a notch opening in a rear face of the plunger and a lug formed as an eccentricity on the pushrod and fitted in the notch. A shoulder on the pushrod proximate the lug presses against a bottom surface of the notch to provide the driving connection between the pushrod and the plunger.

Abstract: An expansion reservoir is disclosed, which has a fluid chamber defined by a reservoir bottom and a flexible reservoir top movable relative to the reservoir bottom as a function of the reservoir filling level, wherein a hydraulic connection to a master cylinder is provided at the reservoir bottom while the reservoir top comprises a substantially liquid-tight but air-permeable connection to the atmosphere, in order to allow pressure compensation between an air volume left in the filled fluid chamber and the atmosphere. The hydraulic connection to the master cylinder comprises an extension protruding into the fluid chamber, which extension defines a predetermined volume V in the fluid chamber which is larger than the air volume left in the filled fluid chamber. In addition thereto, the reservoir top may take the form of a rolling lobe bellows, which comprises a plurality of wall portions substantially concentric at least in the undeformed state.

Abstract: A diaphragm assembly for use with a hydraulic apparatus. The diaphragm assembly includes a cap formed of a rigid material and a diaphragm formed of an elastomeric material. The diaphragm is generally tubular and includes an upper annular collar portion defining an open upper end of the diaphragm and a main body portion extending downwardly from the collar portion, defining a closed lower end of the diaphragm, and including, in cross-section, a plurality of hollow radially extending circumferentially spaced arms.

Abstract: A hydraulic piston-and-cylinder arrangement has a piston to which a signal element is assigned and which is accepted movably in a longitudinal direction in a cylinder housing, at which a position sensor is secured, by means of which an axial position of the signal element and therefore of the piston in the cylinder housing can be sensed. The signal element is fitted to the piston by means of a holding cap. As a result, a hydraulic piston-and-cylinder arrangement with a device for sensing the piston position is created, in which the signal element of the sensing device, which signal element operates in conjunction with the position sensor on the cylinder housing, can be fixed in a simple manner on the piston, which also permits a sizing of the signal element largely independent of the piston geometry.

Abstract: A central release device (10) is disclosed having a cylinder housing (12), with a cylindrical wall (14), and a guide sleeve (16), which is arranged concentrically therewith and on which an annular piston (18), which can be operatively connected to a clutch and can be hydraulically actuated by way of a pressure chamber (20) defined by the cylindrical wall and the guide sleeve, is displaceably guided. At its end the guide sleeve has an annular flange (22) with an end face (24) facing away from the annular piston and a radially outer circumferential surface (26), by way of which flange the guide sleeve is fixed to an end face (28) of the cylinder housing.

Abstract: A device for articulated connection between a control element and a control rod having a ball head comprising a main body attachable to the control element. The main body envelops a locating section providing positive location for the ball head and has an opening area through which the control rod extends when the device is assembled. According to the invention, the locating section is in two parts whereby the main body forms a part into which the ball head can be introduced through a joint duct located outside the opening, while a molding insertable into the joint duct forms the other part of the locating section. As a result, a simple device is created, guaranteeing connection between the control element and the control rod which is backlash-free or has little backlash.

Abstract: A device is disclosed for the optional engaging and disengaging of a friction clutch for motor vehicles with a preferably hydraulic actuating mechanism, such as a central disengaging device, which, in order to apply an actuating force, is operatively connected with the friction clutch via at least one actuating force transmission member, such as a release bearing, which is pre-stressed in the disengaging direction by means of a spring. The device also has a sensor device with a sensor for sensing a variable representative of the engaging respectively disengaging state of and/or the state of wear on the friction clutch. According to the invention, the force of the spring for pre-stressing the actuating force transmission member or of a spring arranged in parallel with it can be sensed using the sensor, as a variable representative of the disengaging and engaging state of and/or the state of wear on the friction clutch.

Abstract: A hydraulic piston-and-cylinder arrangement, in particular for a hydraulic clutch control for motor vehicles, has a piston to which a signal element is assigned and which is accepted movably in a longitudinal direction in a cylinder housing, at which a position sensor is secured, by means of which an axial position of the signal element and therefore of the piston in the cylinder housing can be sensed. The signal element is fitted to the piston by means of a holding cap. As a result, a hydraulic piston-and-cylinder arrangement with a device for sensing the piston position is created, in which the signal element of the sensing device, which signal element operates in conjunction with the position sensor on the cylinder housing, can be fixed in a simple manner on the piston, which also permits a sizing of the signal element largely independent of the piston geometry.