Abstract: A hydraulic cylinder, in particular a master cylinder for a hydraulic clutch actuation system for motor vehicles, has a housing having a cylinder wall, in which a piston is slidably received to seal off the pressure chamber, whereas the pressure chamber in a rest position of the piston is connected to an after-running region by equalization grooves of an after-running device. The cylinder wall of the housing is provided with profiled cut-outs on its piston-side end at least in a lower region in the installed position of the cylinder, which cut-outs each have an upper boundary surface which in the installed position of the cylinder rises up to the equalization grooves of the after-running device.

Abstract: A piston arrangement for master and/or slave cylinders of a hydraulic actuating device for clutch and/or brake systems on motor vehicles is disclosed. An insert is inserted into a recess of the piston up to a first stop, the insert having a ball seat and an expandable insertion sleeve which is undercut with respect to the ball seat and protrudes with its expandable region. A ram is pushed into the sleeve with its ball end until it snaps into the ball seat. As the ram is further pressed axially, the insert slides over the first stop, is firmly pressed into a narrow hole section of the recess and strikes a second stop at the inner end of the recess. The insertion sleeve is then tightly enclosed by the piston wall and can no longer expand even in the event of very high pull-out forces, i.e. cannot release the ball end of the ram.

Abstract: A device (16) for sensing the axial position, in relation to the other component, of one of two components mobile relative to each other, in particular a piston (12) in relation to a cylinder housing (14), which device has a magnetic signal element (18) arranged on the one component and a magnetic-flux-sensitive sensor (20, 20?) arranged on the other component, of which the axial relative position of the signal element to the sensor can be detected. One flux guide element (22, 22?) is allocated to the sensor stationary in relation to the sensor, which extends on the other component at least over the area to be detected of the axial relative positions of the signal element to the sensor and comprises a plate section of a magnetizable material, wherein the sensor is arranged at one longitudinal end of the flux guide element outside the area to be detected of axial relative positions.

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 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 mounting is disclosed for a pressure line, in particular a brake line, which comprises a pipe part connected with a hose portion by means of a connector, which pipe part may be connected to a pressure connection of a housing, in particular of a brake caliper, by means of a fitting. A retaining clip is provided which has a first portion, by means of which the pressure line may be supported at the connector or the pipe part, and comprises a second portion connected rigidly with the first portion, by means of which second portion the retaining clip may be fixed to the housing via the fitting. Thus, a mounting of simple design is provided for the pressure line, which assists or ensures secure and reliable connection of the pressure line to the pressure connection.

Abstract: A hydraulic control device operates a sliding selector shaft, in particular a gearbox for motor vehicles, with a bore made in a wall of a gearbox housing for accommodating a plastic piston. The piston is actively connected to the sliding selector shaft and delimits a pressure chamber and, under hydraulic pressure, radially guides and axially displaces the sliding selector shaft. The piston has a body and a guide section consisting of plastic. The piston is guided directly at the bore, designed as a non-reinforced and unlined cylinder bore, in the wall of the gearbox housing, consisting of a light metal alloy. This creates control device, which is of a much simpler, and more compact design compared with prior art.

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: 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. According to the invention, 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 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.

Abstract: A device is disclosed to reduce vibrations in a hydraulic force transfer system which has a master cylinder and a slave cylinder connected with this via a fluid column. The device has a housing and a membrane attached by its edge to the housing. The housing and the membrane delimit a chamber which can be connected via a connection with the master cylinder and via a further connection with the slave cylinder so that the membrane can be hydraulically pressurized by the fluid column between the master cylinder and slave cylinder. According to the invention the membrane is pressed, at least in the rest state of the hydraulic force transfer system, by means of a spring element against the direction of the hydraulic pressure on the membrane against a chamber-side support surface. The result is a simply constructed device to reduce vibrations in a hydraulic force transfer system.

Abstract: A piston for the variable delimitation of a pressure chamber in a housing of a hydraulic cylinder, in particular a clutch master cylinder for motor vehicles, has a main section on which a running surface is provided for a sealing element on the housing side. The sealing element seals a pressure chamber in an operating position of the piston. The piston also has an after-running device, which, in a normal position of the piston, connects the pressure chamber to an after-running area. The after-running device is made separately from the main section and is connected without play to the main section to form the piston. As a result, a piston that is easy to manufacture is created and which, with reference to the after-running device, has an improved functionality compared with prior art.

Abstract: A device for actuating a clutch, more particularly for motor vehicles, is disclosed, which has an operating lever pivoted on a bearing point, the operating lever being effectively connected to a master cylinder for the production of actuating pressure. The device also has a top dead center spring pivoted on a bearing point, which is articulated with the operating lever is in a position between dead center and an end position it exerts a force on the operating lever in the direction of this end position. According to the invention, both the bearing point for the top dead center spring and also the bearing point for the operating lever are provided on the master cylinder. An actuating device of simple design is thus created which can easily be mounted at the respective place of assembly, for example on the stationary pedal frame of a motor vehicle.

Abstract: A device is disclosed to reduce vibrations in a hydraulic force transfer system which has a master cylinder and a slave cylinder connected with this via a fluid column. The device has a housing and a membrane attached by its edge to the housing. The housing and the membrane delimit a chamber which can be connected via a connection with the master cylinder and via a further connection with the slave cylinder so that the membrane can be hydraulically pressurized by the fluid column between the master cylinder and slave cylinder. According to the invention the membrane is pressed, at least in the rest state of the hydraulic force transfer system, by means of a spring element against the direction of the hydraulic pressure on the membrane against a chamber-side support surface. The result is a simply constructed device to reduce vibrations in a hydraulic force transfer system which can easily be adapted in respect of response behavior and volume increase to the requirements in each case.