Abstract: To insure that no air bubbles are included in a pump of an anti-locking system, the pump is placed into the master brake conduit, thereby causing it to be scavenged by manual brake operation. Once a brake pressure of about 5 bar is attained, a switch-over valve (28) is switched-over, causing the master brake conduit in the pressure build-up direction to be blocked. Additionally pressure fluid is supplied to the secondary conduit (26) and a pressure opening valve (27). The pressure decrease is effected through the direct conduit (13). In the event of a brake slip control, the pump takes in pressure fluid from the reservoir (25) through the suction valve (22).

Abstract: A brake pressure control apparatus for automotive vehicles with an anti-locking control system (ABS) and/or with a traction slip control system (TSS) is presented. In the inlet line to the wheel cylinder an inlet valve is provided which affords a change-over from an orifice function into a flow limiting valve function at a predetermined wheel cylinder pressure. Flow is initially through an orifice (6) in a control slide valve piston (20), held in its initial position by a prestressing spring (23) acting through an auxiliary piston in engagement with control slide valve piston (20). An increase in pressure in the wheel cylinder (13), also exerted in the wheel cylinder pressure chamber (9), to a predetermined level, causes the auxiliary piston (27) to disengage from the control slide valve piston (20), preventing the force of the prestressing spring (23) from acting on the control slide valve piston (20).

Abstract: A hydraulic anti-locking brake unit is presented in which the brake line is shut off by an isolating valve 20 during a control action. For the reduction of the pressure, the outlet valve 7 is opened, so that the pump 14 delivers hydraulic fluid out of the wheel brake into the high-pressure accumulator 19. For a renewed pressure build-up, the inlet valve 6 is opened, so that hydraulic fluid flow is directed out of the high pressure accumulator 19 to the wheel brake. In order to be able to utilize a high pressure accumulator having a low receiving capacity, various valving arrangements are disclosed to direct excess flow from the pump either to the master cylinder or a low pressure accumulator.

Abstract: An anti-lock-controlled brake system for automotive vehicles is described, with a braking pressure generator (6), connected via a main pressure line (5) to a wheel brake (1) with an auxiliary hydraulic pressure pump (2) connected to an auxiliary pressure line (12), and a pressure medium accumulator (19) connected to a pressure limiting valve (3) control-lable in dependence on the hydraulic pressure of the wheel brake (1). A control of the accumulator pressure and volume within a closed hydraulic system is thereby provided which will take place in dependence on the wheel brake pressure to be in conformity with actual requirements.

Abstract: In brake systems with a large boosting factor, relatively high pressures in the tandem master cylinder during an anti-lock control operation caused by start-up of a pump are prevented by an adjusting member which is controlled in response to the wheel braking pressure, to act upon a pressure-reducing valve inserted upstream of a power booster, so as to limit the booster pressure.

Abstract: A process for adjusting the travel sensor for a brake power booster movable wall is disclosed to compensate for tolerance variations, in which a fixed stop is installed to engage the output member upon applying a predetermined input force to shift the movable wall to a test location. The distance to the test location of the movable wall from a booster housing reference surface is measured with a measuring instrument installed temporarily in the booster housing opening normally receiving the travel sensor. The tips of the travel sensor is positioned at the test location with the travel sensor in the corresponding signal condition either by using an appropriately dimensioned replaceable tip or sensor holder, or by use of an adjustable length sensor holder.

Abstract: A hydraulic anti-locking brake unit is presented in which the brake line is shut off by an isolating valve (20) during a control action. For the reduction of the pressure, the outlet valve (7) is opened, so that the pump (14) delivers hydraulic fluid out of the wheel brake into the high-pressure accumulator (19). For a renewed pressure build up, the inlet valve (6) is opened, so that hydraulic fluid flow is directed out of the high-pressure accumulator (19) back to the wheel brake. In order to be able to utilize a high-pressure accumulator having a low receiving capacity, various valving arrangements are disclosed to direct excess flow from the pump either to the master cylinder or a low pressure accumulator.

Abstract: There is presented a method for assembling a tandem master cylinder and a vacuum brake power booster of a hydraulic brake system for automotive vehicles. Air is injected via the pressure connections (19, 36) of the pressure chambers (11, 18) associated with the pistons (2, 3). Simultaneously, the pistons (2, 3) are moved in the direction away from the brake pedal. The pressure increase in the pressure chamber (18) is measured during the movement of the pistons (2, 3) and thus during the movement of the central valve (14) accommodated in the floating piston (3). The air pressure in chamber (18) will rise as soon as the closing member (15) of the central valve (14) has moved to sit on the valve seat (16) and the central valve is closed thereby. A trigger point which determines a measured distance on the abscissa of the diagram is fixed in the curve of the diagram "Pressures as a function of the travel of the central valve", the said curve indicating the pressure increase.

Abstract: In an anti-lock brake system, a differential pressure limiter (8) is connected in front of the inlet valve (6). This causes a defined pressure gradient to always prevail at the inlet valve (6), what appreciably reduces the noise emission of the valve during an anti-lock braking operation. Since the inlet valve (6) has a slight throttling effect in its opened position, it may occur that on brake operation with cold brake fluid a pressure gradient is generated at the inlet valve (6) which results in the differential pressure limiter closing. It is therefore suggested to arrange a bimetal spring (20) in parallel to the control spring (15) of the differential pressure limiter (8), which bimetal spring expands at low temperatures and cases a force in addition to the spring force of the control spring (15) to act on the control piston.

Abstract: A brake pressure control for use with an automotive anti-locking control system (ABS) and/or a traction slip control system (ARS) is provided. The control comprises a pressure modulator for varying the hydraulic pressure in the wheel cylinder (13) during the brake pressure control mode, with the pressure modulator exhibiting at least one inlet valve and at least one outlet valve (21) associated with the wheel cylinder (13), at least one motor-driven pump (6) for generating a hydraulic pressure, and an electronic controller. The inlet valve is pressure actuated and comprises a piston-cylinder assembly including a piston (7) forcing, upon application of the brake pressure, a filling volume (14) into the wheel cylinder (13), followed by a throttled rise in pressure caused by a throttling flow restriction (16) defined through the piston.

Abstract: A brake pressure control apparatus for automotive vehicles with an anti-locking control system (ABS) and/or with a traction slip control system (TSS) is presented. In the inlet line to the wheel cylinder an inlet valve is provided which affords a change-over from an orifice function into a flow limiting valve function at a predetermined wheel cylinder pressure. Flow is initially through an orifice (6) in a control slide valve piston (20), held in its initial position by a prestressing spring (23) acting through an auxiliary piston in engagement with control slide valve piston (20). An increase in pressure in the wheel cylinder (13), also exerted in the wheel cylinder pressure chamber (9), to a predetermined level, causes the auxiliary piston (27) to disengage from the control slide valve piston (20), preventing the force of the prestressing spring (23) from acting on the control slide valve piston (20).

Abstract: In an anti-lock brake control system having a vacuum brake power booster and a tandem master cylinder, in which the brake pedal is controlled to be positioned forwardly of the initial return position during the anti-lock control mode. This is achieved by variation of the rate of delivery of an auxiliary pump as by switching the pump motor on and off by a switch actuated by the diaphragm of the power booster to provide a signal of the pedal position at the start of an anti-lock control phase. Various switching arrangements described include a Bowden-cable pulled by the diaphragm, a mechanical or an optical switch actuated by the rolling lip of the diaphragm, or an approach switch detecting the approach of the diaphragm and cam-assembly. The core (53) of the Bowden cable (54) is connected with the diaphragm plate (52) of the vacuum brake power booster. The core (53) moves the trigger cam (64). The switch (18) is actuated by the movement of the trigger cam (64).

Abstract: A travel sensor for measuring mechanical quantities of motion, in particular for determining the brake pedal position, comprising a transmission unit axially slidable in a housing and comprising a measuring apparatus for generating an electric signal representative of the travel of the transmission unit. The transmission unit is formed of two mechanical transmissions elements (12, 13 and 3, 6, respectively) corresponding with each other and effecting a reduction of the introduced quantity of motions that the test signal is tapped by a reduced test travel. This provides a travel sensor of particularly short dimensions which permits to use of Hall-effect sensors.

Abstract: A tandem master cylinder for hydraulic brake systems for automotive vehicles, with the brake systems comprising a brake pressure control means, in particular, an anti-locking control means. The tandem master cylinder has a push rod piston (7) and a floating piston (8), with each piston having a central valve. The valve closure member (13) of the central valve in the push rod piston (7) can be controlled both by a pin (16) directly or indirectly abutting the housing of the tandem master cylinder and by a pin (17) coupled to the floating piston.

Abstract: A tandem master cylinder (1) with central valves (12, 37) positioned in the secondary piston (15), separate from the latter at the end of the cylinder bore (2) and arranged with filter elements (27, 28, 48, 49) upstream of the central valves (12, 37) so as to protect the latter from dirt. In order to be able simultaneously to reduce the total overall axial length, hydraulic fluid flows radially through the filter elements (27, 49) which become effective in the event of a backflow of hydraulic fluid and said filter elements (27, 49) are positioned on the pedal side in respect of the second stop (14) of the secondary piston (15), respectively radially aside the closing spring (46) of the second central valve (37).

Abstract: To control the pressure at the outlet of a pump and to position the pedal during a brake slip control action, an additional arrangement is provided to an existing master brake cylinder which arrangement comprises a transmission piston (5) as well as a shut-off valve (30). The closure member of the shut-off valve is loaded by way of a valve piston (28) and by the pressure in the brake line (18') in opposition to the pressure at the outlet of the pump. The valve closure member is thus pressure-balanced so that no forces are transmitted onto the tappet (37). Therefore, the ramp (40) at the transition piston (5) need not be separately hardened during the manufacturing process.

Abstract: A method is suggested for assembling a tandem master cylinder and a vacuum brake booster of a hydraulic brake system for automotive vehicles. Air is injected via the pressure connection (19) of the pressure chamber (18) associated with the push-rod piston (2). Simultaneously, the push-rod piston (2) is moved in the direction pointing away from the brake pedal. The pressure increase in pressure chamber (18) is measured during the movement of the push-rod piston and, thus, during the movement of the central valve (6) accommodated in the push-rod piston. As soon as the closure member (5) of the central valve is seated on the valve seat (4), thus the central valve being closed, the air pressure will increase in the chamber (18). In the curve of the "pressure-against-central-valve-travel" diagram, which curve indicates the pressure increase, a trigger point is established which determines a measured distance on the abscissa of the diagram.

Abstract: A tandem master cylinder for hydraulic brake systems of automotive vehicles. The push-rod piston (29) and the floating piston (34) both are provided with a central valve. The central valve of the push-rod piston is coupled to the floating piston. The length of the bore (28) of the central valve in the push-rod piston (29) is dimensioned to allow the valve closure member (27) of the central valve in the push-rod piston to travel a distance within the bore of the central valve at least equal to the stroke of the floating piston (34).

Abstract: An anti-lock hydraulic brake system comprising a separating valve (14) and a regulating valve (19). A combined arrangement is provided wherein the valves are connected into each other. The movability (play s) of the piston (30) affords the event that a compensating volume for the control action in the event that the output of the pump is insufficient in specific situations requiring a large amount of fluid for control.

Abstract: A tandem master cylinder for a hydraulic brake unit with slip control. In the housing of the brake unit a primary piston pre-loaded by a first return spring and a secondary piston pre-loaded by a second return spring define a primary and a secondary pressure chamber within a longitudinal bore. The pressure chambers are connected to a fluid reservoir and are associated with a first and a second control valve which release or shut off a second connection between the pressure chambers and the fluid reservoir depending on an actuating force. In order to reduce the overall axial length of the tandem master cylinder, the control valves (10, 11) are arranged outside the pistons (6, 7) and are actuated linearly by the pistons (6, 7).