Abstract: An assisted braking device comprises a master cylinder and piston for applying the brakes. Depression of a brake pedal is arranged to move the master piston and to control brake assisting means to assist in the movement of the master piston. The assisted braking device is arranged such that if the brake assisting means is defective a driver can still effectively displace the master piston by applying the brake pedal. In this respect a safety rod is connected between a pedal lever of the brake pedal and the master piston independently of the brake assisting means and is arranged to be actuated if the assisting means break down.

Abstract: A servo-assisted hydraulic master cylinder has a variable ratio effect so that brake fluid is initially displaced to the brakes at a high rate with respect to driver pedal movement and then at a low rate when an appropriate pressure has developed. A stepped piston assembly comprising a first piston slidable in a second piston defines a first chamber which is directly connected to the brakes and a second chamber in which a variable pressure is developed. The first piston is operated directly by the pedal through the servo valve and is subject only to brake pressure in the first chamber so that brake pressure is proportional to driver effort during normal operation. The second piston is operated by the servo diaphragm through the servo valve housing.

Abstract: An assisted braking device comprises a master cylinder and piston assembly the piston of which is connected to the piston of an assisting jack by an axially aligned interconnecting element. A brake pedal is adapted to operate the interconnecting element by a thrust member and a lever which is articulated to the interconnecting element and connected at one end to the thrust member; the other end of the lever acts on a distributor which can direct hydraulic fluid under pressure to the existing jack. A force on the brake pedal is transmitted via the thrust member and the lever to the interconnecting element to displace the master piston, and the end of the lever acting on the distributor simultaneously energizes the assisting jack. Safety abutment means which operate in the event of failure of the assisting hydraulic pressure allow displacement of the master piston by the force directly applied through the thrust member.

Abstract: In a brake system, the addition of an auxiliary cylinder or booster cylinder for use in conjunction with a master cylinder and brake lever to increase force.

Abstract: An installation for the servo-assist of actuating devices in motor vehicles, especially of a hydraulic brake system, in which a control member, such as the brake pedal, acts on an actuating device, such as a master cylinder of a two-circuit brake system by way of a servo-member; a hydraulically actuatable servo-unit is thereby arranged between the control member and the actuating device whose first part is supported at the control member and whose second part is connected with the actuating device; the actuation of the servo-unit is controllable from a hydraulic pressure medium source in the manner of a follower control by means of a control device connected with the control member.

Abstract: A servo brake system with at least two circuits, equipped with a tandem master cylinder, in which two working pistons are arranged coaxially one behind the other; a transmission shifting device thereby automatically shifts in case of failure of the servo installation to a larger pedal travel with a mechanically applied brake pressure that is reduced within permissive limits; the working piston of the actuating side thereby includes a bore coaxial to the other working piston, in which a plunger piston is guided which is actuatable by the input piston.

Abstract: A control valve assembly for a vehicle dual hydraulic braking system in which hydraulic fluid from a distributor chamber can be supplied to one or both of a pair of outlets for connection to brakes on opposite sides of a vehicle. The assembly incorporates a pressure control valve operable to supply fluid under pressure to the chamber from an outlet for connection to a pressure source, irrespective of whether one or both of two separate brake-applying valves are to be operated, and a one-way valve is located on the upstream side of the pressure control valve to prevent flow in a reverse direction. A back-up piston works in a bore in communication with the chamber, and is provided to pressurize fluid in the chamber after an exhaust valve has closed and a pressure control valve has opened.

Abstract: For the hydraulic brake system of a vehicle such as a farm or industrial tractor having brakes on the right and left rear wheels for both braking and steering, flow control means operatively interconnecting a source of hydraulic pressure available when the vehicle is operating, a hydraulic fluid reservoir and a manually actuated brake applicator means such as a brake pedal, so as to provide power braking. The flow control means also provides for manual braking when hydraulic pressure is not available. A separate relatively large fill piston and small pressurizing piston used in manual braking are in combination with the power brake valve. An unloading valve is provided for cooperation with the fill piston during both the power and manual modes.

Abstract: A servo-assisted hydraulic master cylinder has a variable ratio effect so that brake fluid is initially displaced to the brakes at a high rate with respect to driver pedal movement and then at a low rate when an appropriate pressure has developed. A stepped piston assembly comprising a first piston slidable in a second piston defines a first chamber which is directly connected to the brakes and a second chamber in which a variable pressure is developed. The first piston is operated directly by the pedal through the servo valve and is subject only to brake pressure in the first chamber so that brake pressure is proportional to driver effort during normal operation. The second piston is operated by the servo diaphragm through the servo valve housing.

Abstract: A closed-center brake system and brake valve are disclosed. A closed-center variable displacement pressure compensated pump delivers fluid pressure to a valve inlet which carries a normally closed check valve. When a valve operating rod is partially withdrawn from the valve, the check valve opens to admit fluid to a valve chamber; fluid pressure and flow are directed from the chamber to ports leading to a vehicle left-hand brake and a vehicle right-hand brake. Should fluid pressure be lost in upstream portions of the system, further pulling action on the valve rod will collapse the chamber and manually deliver pressurized fluid to the brakes. Another brake valve outlet port, located just downstream of the inlet check valve, provides for delivery of pressure compensated fluid back to the pump to cause the pump to operate with desired characteristics.

Abstract: A power brake valve and a related braking system are disclosed. The valve comprises a housing defining a first bore of large diameter and a second bore of smaller diameter, and annular pistons are slidably disposed within each bore. A biended rod, also slidable within the bores, carries reaction pistons which are radially extended to cover the annular flow space of the adjacent, associated annular pistons. When the rod is pulled in a power mode of operation, each annular piston moves toward the associated annular piston to restrict and halt the normal flow of fluid through the annular piston and create a movable end wall. As pressure rises within the chambers, pressurized fluid is discharged from the valve to brake units to cause braking action. In a manual mode of operation, pulling action on the rod causes a relatively large quantity of relatively low pressure fluid to be discharged from the first chamber so as to quickly and effectively take up systemic clearances within the brake system.

Abstract: A booster operated master cylinder piston for use in an anti-skid braking system includes a modulator piston located between the master cylinder piston and the booster valve assembly. In the event of a skid the pressure of booster fluid acting on the modulator piston is equalized across the modulator piston.

Abstract: A vehicle brake booster and master cylinder assembly has a vacuum suspended booster section and a hydraulic booster section in series, and a master cylinder unit in series with the booster sections. During normal operation the vehicle operator obtains boosted brake actuating pressures from the master cylinder by operation of the hydraulic booster section throughout the normal stroke of both booster sections without operating the vacuum booster section. If additional brake actuating pressure is required after the hydraulic booster has reached its run-out condition, the master cylinder is actuated normally through mechanical force transmitting elements which are parts of the booster sections. If there is no hydraulic pressure available for hydraulic booster operation, the control valves of the booster sections move from the first range of operation which normally controls the hydraulic booster section to a second range of operation which actuates the vacuum booster section.

Abstract: A motor vehicle fluid power circuit is provided with a constant displacement pump, a control valve, an open center steering valve, and a brake booster with a spring type ratio changer. The brake booster includes an input rod which is connected to a brake pedal of the vehicle and an output rod which is connected to the brake master cylinder of the vehicle. One predetermined ratio of input rod movement to output rod movement is established under normal operating conditions, and a one-to-one ratio is established under emergency conditions when sufficient pressure from the pump is not available for the brake booster.

Abstract: A brake force booster installation with a mechanical, pneumatic or hydraulic actuating mechanism acting on a servo- and adjusting-unit, which in turn acts on the master cylinder, with filling devices and with control- and shifting-devices; the filling devices and the actuating mechanism are thereby actuated by movement of the brake pedal lever pivotally connected at two connecting points to the piston rods of an actuating piston and of a filling piston while the filling devices and the actuating devices are so arranged separated from one another and are so connected with the control and shifting devices that the brake pedal lever during its idle path is actuated with one lever ratio by holding fast one piston rod and thereupon the working effect is realized by automatically shifting to a different translation ratio.

Abstract: A brake booster and master cylinder assembly operates the front wheels of a vehicle and a slave booster and master cylinder assembly operates the rear wheels of the vehicle. A solenoid controlled valve in a conduit connecting the variable pressure sides of the booster units normally permits free air passage. When energized for wheel lock control purposes, it blocks the flow of air between the two boosters, admitting engine vacuum to the high pressure side of the slave booster. This decreases rear brake actuating pressure under control of a logic system.

Abstract: The invention relates to a hydraulic servomotor comprising a housing provided with a bore slidably receiving two pistons separating an actuating chamber from an utilization chamber, said pistons including an annular outer piston and an inner piston received within the annular piston. Releasable coupling means are provided between both pistons to permit said pistons to move in unison when high pressure fluid is available in the actuating chamber and to permit the inner piston to be moved alone by the push rod in the event of a high pressure failure in the actuating chamber. The motion of the outer piston towards the interior of the actuating chamber is limited by an abutment fixed to the housing.

Abstract: A hydraulic transmission is provided between the booster piston and the master cylinder piston which is automatically interrupted if the booster power is not present. In this arrangement, when booster power is not present, a sufficient pressure can be generated with brake pedal effort alone, making use of the full permissible pedal travel.

Abstract: The brake force regulator of this invention provides for genuine dual circuit control so that in the event of failure of one of the intact brake circuits, control of the other can be continued at an increased switching point pressure. The brake force regulator of this invention includes a pair of axially displaceable stepped pistons which make fluid connections to both brake circuits in the same manner. A control chamber is defined by both stepped pistons on the one hand and a control piston to which is applied to control force on the other. A fluid connection is provided between thecontrol chamber and the brake circuit controlled by each stepped piston which is opened when the control piston approaches either of the stepped pistons. The faces of the stepped pistons to which is applied the pressure in the control chamber is smaller than the face of the control piston upon which the pressure in the control chamber acts in the opposite direction.

Abstract: The invention relates to a brake control device including, a pump driven by an engine, a brake pedal actuated by a vehicle driver, wheel brake cylinders, manual operating means operatively connected with the brake pedal, pressure control valve means having a hollow seat member provided with a normally open-passage therein and a valve seat thereon and conrolling the hydraulic fluid to the pump according to the actuation of the manual operating means, flow regulating valve means having a variable orifice and a fixed orifice and supplying the hydraulic fluid to the passage of the pressure control valve means through the fixed orifice, power piston means actuated according to the actuation of the pressure control valve means, and master cylinders operatively connected with the power piston means for supplying the fluid pressure to the wheel brake cylinders.

Abstract: A booster operated master cylinder piston for use in an anti-skid braking system includes a modulator piston located between the master cylinder piston and the booster valve assembly. In the event of a skid the pressure of booster fluid acting on the modulator piston is equalized across the modulator piston.

Abstract: A master cylinder assembly for a vehicle hydraulic braking system comprises a pedal-operated valve assembly for controlling a supply of fluid under pressure to a power chamber in a housing on the opposite side of a piston to a pressure space which has an outlet for connection to a wheel brake, and a second piston is adapted to be applied by the pedal to generate fluid pressure in said pressure space.