Abstract: A method for functional testing of an electromechanical fill level monitoring device. In order to test the plausibility of a signal emitted by a fill level monitoring device of a first pressure medium chamber, a forced actuation of this fill level monitoring device is carried from time to time. This forced actuation is carried out in that a pressure medium delivery unit in a pressure medium circuit having the first pressure medium chamber is activated for a predefined period. This delivers the pressure medium fill level monitoring device into a second pressure medium chamber via a pressure medium connection. On the basis of the signal profile output by the fill level monitoring device, the proper operation of the fill level monitoring device is inferred in the electronic control unit.

Abstract: An integrated power brake unit (20) includes an input rod (30) operable to receive a driver braking input force, a booster operable to boost the driver braking input force, a master cylinder, a pump operable to provide pressurized fluid for braking, in lieu of the master cylinder, in response to the driver braking input force, and a fluid reservoir (36) defining a main chamber. The fluid reservoir (36) has first and second outlet ports (P1, P2) in fluid communication to supply the master cylinder, and a third outlet port (P3) in fluid communication to supply the pump, each of the first, second, and third outlet ports (P1, P2, P3) being provided in a bottom wall (48) of the fluid reservoir (36). The fluid reservoir (36) includes a sub-chamber (42) within the main chamber, the sub-chamber (42) covering the third outlet port (P3), and defining an opening (56) to the main chamber at a forward-most end of the sub-chamber (42).

Abstract: The present invention relates to a liquid reservoir for a vehicle that is subjected in service to inclinations in at least two different directions, the reservoir comprising a float well which delimits a bowl containing a float that is able to move depending on the level of liquid in the reservoir. The reservoir is characterized in that the float well comprises at least two retention means positioned successively along a flow path of the liquid as far as the bowl, from the outside toward the inside of the float well, each retention means keeping liquid in the float well if the reservoir is inclined in a set of directions specific to this retention means. The invention also relates to a motor vehicle system comprising such a liquid reservoir and means for binary detection of the level of liquid in the reservoir.

Abstract: A hydraulic operating apparatus for a small vehicle, including a bicycle, comprises a housing, a piston, a mounting assembly, a lever, and a fluid reservoir tank. The housing includes a cylinder bore extending along a cylinder axis. The piston is movably disposed within the cylinder bore. The mounting assembly is configured to mount the housing to a handlebar of the small vehicle. The mounting assembly defines a handlebar mounting axis that is not perpendicular to the cylinder axis in a mounted state where the housing is mounted to the handlebar. The lever is pivotally mounted to the housing and configured to move the piston within the cylinder bore in response to a movement of the lever. The fluid reservoir tank has a lid opening. The lid opening is configured to face a center plane that passes through a geometric center of the handlebar and that is perpendicular to the handlebar mounting axis, in the mounted state.

Abstract: The present invention relates to a pumping device for delivering and metering fluids, in particular medical fluids such as dialysis fluids, with a piston unit having a driving device and a piston and with a membrane unit which has a membrane and a first chamber bordered by the membrane. The pumping device also has a hydraulic unit which has a space to accommodate a hydraulic fluid which is connected to the piston of the piston unit and to the first chamber of the membrane unit. The reliability of metering by such a pumping device is increased by providing a control unit for guaranteeing a predefinable metering rate and/or quantity and also providing a measuring device by means of which the axial position of the piston unit can be determined directly and which can be connected to the control unit.

Abstract: A tube-line pressure sensor of a medical-appliance driving apparatus detects the interior pressure of a tube line. If the pressure detected by a tube-line pressure sensor is equal to or less than a predetermined value, a first solenoid valve is closed, while a second solenoid valve is opened, whereby a gas is supplied from a secondary gas tank to the tube line. The amount of gas supplied to the tube line is calculated based on a pressure change in the tank detected by a tank pressure sensor. In actual use, natural gas leakage during normal operation can be clearly distinguished from abnormal gas leakage due to an accident. The interior pressure of the tube line is detected at a time when the balloon is about to inflate from the deflated state, and a gas supply system supplies the driving gas to the tube line so that the detected pressure becomes a preset pressure value. A controller can change the preset pressure value.

Abstract: A brake system (10) having a proportioning device (18) through which a first fluid pressure is communicated to a first brake circuit and a second fluid pressure is communicated to a second brake circuit. The proportioning device (18) has a housing (90) with a first bore (204) connected with a first passage (98) for receiving the first fluid pressure and with a second passage (100) for receiving the second fluid pressure. A first piston (210) located in the first bore (204) of the housing (90) separates the first passage (98) from the second passage (100). The first piston (210) responds to a higher fluid pressure of the first and second fluid pressures by moving in the first bore (204) to providing additional fluid pressure to a lower fluid pressure of the first and second fluid pressures to substantially equalize the first and second fluid pressures supplied to the first and second brakes circuits for effecting said brake application.

Abstract: An actuating unit for a hydraulic brake system for automotive vehicles which operates by a precisely defined change-over pressure and with lost travel independent of the speed of actuation. The actuating unit includes a pneumatic brake power booster and a master brake cylinder connected downstream of the pneumatic brake power booster. The master brake cylinder contains a primary piston coupled with an annular piston of larger diameter. The annular piston confines a filling chamber which may be connected to the hydraulic pressure chamber. The annular piston is adapted to uncouple from the primary piston when the pressure acting on the annular piston reaches a predetermined amount. Thus, the displacement of the filling volume by the annular piston does not require an entire stroke of the master brake cylinder.

Abstract: A hydraulic dual-circuit brake system has brake booster with a first output pressure chamber allocated to the front-axle brake circuit I and a second output pressure chamber allocated to the rear-axle brake circuit II. The chambers are movably delimited by master cylinder pistons, to each of which is allocated a position sensor. An electronic control device is provided to process the output signals of the position sensors and to emit control signals for a valve arrangement by which a brake circuit which is poorly bled or leaking is blocked off from its master brake line.

Abstract: A vacuum brake power booster is presented in which the vacuum control valve (81) is arranged parallel to the master cylinder (55). The housing (92) of the booster is used as a carrier element for actuating members, such as the brake pedal (60, 8) and the clutch pedal (11) as well as for other elements. A twin master cylinder is employed. A short overall axial length and a space-saving design of the assembly as a whole, enabling efficient incorporation of the overall assembly at the assembly line of the vehicle manufacturer, are achieved by the selection and arrangement of the components of the brake power booster and of the master cylinder, as well as of the actuating members.

Abstract: A brake pedal travel warning system for use in an automotive vehicle includes a brake pedal and a master cylinder associated with the brake pedal through a connecting link. The master cylinder includes a fluid reservoir containing brake fluid and a housing including an internal bore communicating with the fluid reservoir through a reservoir port, the bore defining a primary chamber and a second chamber. A primary piston is slidably disposed in a primary chamber and reciprocally moves therein. A secondary piston is slidably disposed in the secondary chamber. The master cylinder further includes a signal generation means associated with the primary piston for generating a warning signal in response to excessive piston travel in the primary chamber.

Abstract: A master cylinder (12) having a switch (70) which is activated by either a magnet (78) carried by a float (76) in a reservoir (40) or a pin (66) moved by a differential area piston (52). The switch (70) had a first blade (82) connected a source of electrical current (106) through an indicator light (124) and a second blade (88) connected to an electrical ground (114). A reed switch (100) is connected to the first (82) and second (88) blades and responds to the magnet to close an electrical circuit to operate the indicator light (124) if a low fluid level is present in the reservoir (40). A first contact (96) on the first blade (82) is positioned in switch 70 by a non-electrical conductive actuation pin (66) that extends through the housing (22) of the master cylinder (12).

Abstract: A master cylinder having a housing with a first bore therein for retaining a pair of pistons which move in response to an input force and develop fluid pressure to effect a brake application. A second bore in the housing carries a differential area piston connected to the pressure chambers. A reed switch retained in the housing is aligned with a first magnet located on a float in a reservoir and a second magnet is attached to the differential area piston. A ferromagnetic shield located between the reed switch and second magnet has first and second openings located in a plane on either side of the reed switch. Should a failure occur in either pressure chamber, the differential area piston moves to allow magnetic field to pass through the openings in the shield and activate the reed switch to develop a warning signal and inform an operator of a failure mode condition in the master cylinder.

Abstract: A process and apparatus for monitoring and controlling an anti-locking automotive brake system comprising a tandem master cylinder and an auxiliary pressure source, from which, in the event of anti-lock regulation, pressure fluid is supplied to the working chambers of the master cylinder. Auxiliary pressure regulation is performed with the aid of central valves and the auxiliary pressure source is turned on and off in response to the advance of the primary piston, a maximum distance being preset between the primary and the secondary piston. Once this space is exceeded, the central valve disposed in the primary piston, opens resulting in another advance of the primary piston and a switch-on of the auxiliary pressure source. If the primary piston after the auxiliary pressure source having been turned on, is not restored within the predetermined time interval, an error signal will be generated.

Abstract: A brake failure warning system for a dual hydraulic master cylinder for use with a motor vehicle. The warning system employs a pair of Hall Effect magnetic sensors which are positioned on the exterior of a plastic cylinder in association with the two pistons mounted within the bore of the cylinder. The pistons have ferrous frustoconical portions which coact with the respective sensors to generate position signals that vary as the pistons move in the bore past the respective sensors. The two position signals are fed to a logic board which compares the signals and generates an error or warning signal in the event that the difference between the two signals exceeds a predetermined amount indicative of failure of one of the two braking systems of the vehicle.

Abstract: In a brake fluid container for hydraulic motor vehicle brake systems having a housing with a fill connector a container cap closing off the fill connector, a filling filter suspended in the fill connector and protruding into the housing interior, and a level switch secured to the container cap for indicating a minimum allowable fill level in the housing in order to attain extensive damping of a float of the level switch with respect to fluid fluctuations caused by vehicle behavior, the filling filter is embodied as a closed float chamber, extending to below the minimum allowable fill level in the housing with guides for the float. On its lower end, the filling filter is provided with a throttle bore located near the minimum allowable fill level and in a region near the maximum fill level, it is provided with filter windows for the sake of rapid filling of the housing with fluid.

Abstract: A brake system which has a brake booster, a brake pedal which acts via a travel simulator device upon the brake booster, at least one anti-skid valve, two sensors (S.sub.p, S.sub.I) and a pulse emitter. One of the sensors measures braking pressures. The other sensor (S.sub.I) measures the displacement distances of a piston, which is displaced in the brake booster to effect braking. A comparator connected to the sensors (S.sub.p, S.sub.I) switches the pulse emitter on whenever the piston travels a longer displacement distance than is permissible at a predetermined braking pressure. The pulse emitter controls the anti-skid valve such that a driver who actuates the brake system perceives changes in braking acceleration, and these changes are intended to emphatically cause him to seek a repair facility.

Abstract: The invention is a hydraulic failure compensating switch which incorporates a differential pressure valve which responds to a hydraulic failure in one of a pair of vehicle braking circuits and altering the pressure reducing function of the braking system proportioning valve(s) in response thereto to increase braking torque at the vehicle's rear wheels.

Abstract: A hydraulic multiple-circuit brake system is proposed, the brake amplifier of which has a multiple-chambered refill container. With an intake connection of its pump, an energy supply apparatus comprising a pump and a reservoir is connected at a predetermined fill level (h/2) to the refill chamber which is intended for the supply of an open brake circuit (II). In this manner, it is attained that if there is an energy failure, the open brake circuit will be capable, as a closed brake circuit, of continuing to function.

Abstract: A master cylinder assembly of the type that a current quantity of operating fluid in the interior of a reservoir is detected by function of a float means, wherein the float means has an extension extending with its center of buoyancy disposed near the center line of the reservoir.

Abstract: A braking pressure generator for slip-controlled brake systems of automotive vehicles comprises dynamic (III) and static (I, II) pressure fluid circuits into which pressure fluid from the dynamic circuit (III) is metered during braking with slip control. A differential pressure pilot valve (4) is provided which compares the pressure in a booster chamber (15) of the hydraulic circuit (III) with the pressure in a prechamber (5) into which pressure is metered during braking with slip control. The differential pressure pilot valve (4) is connected to an alarm switch (9). The switching position of this alarm switch is logically combined with the switching position of a brake-actuating switch (8) and with the brake slip control signal (10) and an error signal is derived therefrom.

Abstract: A reservoir (20) for a master cylinder (16) has a body (22) with an end member (82) attached thereto by tangs (92, 92' . . . 92.sup.N) that engage a surface (69) on a flange (70). A shoulder (86) concentric to peripheral lip (84) on the end member (82) retains a seal (96). A projection (90) that extends from the end member (82) acts as a stop to assure that a pin (52) on a lever (54) that carries a magnet (60) remains attached to arms (44) extending from the body (22). While motion may move the fluid in compartments (34 and 36) toward flange 70, shoulder (86) acts a first barrier and seal (96) acts as a second barrier to prevent fluid from leaking through the mechanically formed joint. If fluid is lost from the compartments (34 and 36) a float (58) tracks the fluid level and moves magnet (60) toward sensor (64) to inform an operator of the change in fluid level.

Abstract: A hydraulic reservoir in a tandem master cylinder includes a main portion defining a fluid reservoir chamber for reserving brake fluid, two fluid supply portions defining fluid paths under the main portion, the fluid supply portions being contiguous with the main portion and an opening formed at the top, the two fluid supply portions being connected to two fluid connection portions of a tandem master cylinder body.

Abstract: A master cylinder includes a housing movably supporting a pair of pistons and carrying a fluid reservoir assembly. The fluid reservoir assembly carries a differential area piston and a float which cooperate to activate a single reed switch, thereby generating a warning signal for a vehicle operator.

Abstract: A diaphragm assembly is designed to follow a drop in the level of a working fluid filled in a reservoir used with a master cylinder for the purpose of cutting off the communication between the working fluid and the outside air. The diaphragm includes a pair of opposite lower steps in the axial direction. Each of the steps comprises an upright flat portion and an upper flat portion which form parts of the bottom wall and side wall of the diaphragm, when the level of the working fluid in the reservoir reaches a predetermined lower limit. The upper flat portions of the steps are inclined to at a given angle to the horizontal, thus forming an air passage.

Abstract: In a dual master cylinder assembly comprising two independently and simultaneously operable master cylinders, primary pressure spaces between primary and secondary pistons are interconnected by a pipe-line, and secondary spaces between the secondary piston and adjacent ends of the master cylinders are connected to a common auxiliary braking system through a pipe-line. Each secondary piston is provided with an arrangement of passages in communication at all times with a reservoir for fluid, and normally open primary and secondary recuperation valves provide communication between the passages and the respective pressure spaces when the pistons are in their retracted positions. Simultaneous operation of both master cylinders causes both pairs of primary and secondary recuperation valves to close followed by pressurization of the fluid in both pairs of primary and secondary pressure spaces, whereby to apply simultaneously the brakes on opposite sides of the vehicle and to operate the auxiliary braking system.

Abstract: A plastic compensating reservoir for hydraulic brake systems, such as for brake systems of automotive vehicles, is provided with two interconnected brake fluid chambers which are in communication each other over one port for connection to each one pressure chamber of a tandem master cylinder. To enable manufacture of a like compensating reservoir by one single injection molding process, there is provided a tube which extends transversely to the reservoir's vertical axis and which projects from one of the brake fluid chambers, the said projecting end being adapted to be closed.

Abstract: A hydraulic fluid reservoir for automobile including a plurality of fluid chambers separated by a partition, the fluid chambers being communicated with hydraulic systems in the automobile respectively, and a baffle plate between the upper end of the partition and an inlet at the upper portion of a reservoir body to define openings of the respective fluid chambers at predetermined ratios which define the flow rates of fluid into respective fluid chambers.

Abstract: A fluid reservoir for use with a tandem master cylinder is divided into two compartments by a partition wall with one of the two compartments being directly connected to a first outlet port connected to the master cylinder and the other of the two compartments being connected to a second outlet port connected to the master cylinder disposed in the one of the two compartments by a channel formed within the reservoir extending from the other of the two compartments through the partition wall to the second outlet port. This construction ensures the freest possible arrangement of the first and second ports at the bottom of the reservoir.

Abstract: A fluid reservoir for a tandem master cylinder. The fluid reservoir is of a type having therein, as one unit body, two chambers each for supplying hydraulic fluid to each of two pistons of the tandem master cylinder. These two chambers are separated into the right and left sides in the reservoir by at least one partition wall extending longitudinally of the cylinder. The bottom of each chamber is inclined to slope down longitudinally of the cylinder and its fluid outlet communicating with the cylinder is formed at the lowest part of the bottom. A fluid warning device and fluid passages connecting the two chambers are located near a vertical plane passing through the center of mass of the hydraulic fluid in the reservoir and extending laterally of the cylinder.

Abstract: In a fluid reservoir for a brake master cylinder, a cap member of elastic material is coupled over the upper opening of a casing, and a diaphragm seal member is coupled within the cap member to subdivide the interior space of the casing into upper and lower chambers. The seal member is provided at its outer periphery with an inlet check valve assembly and at its inner periphery with an outlet check valve assembly. The inlet check valve assembly is characterized by an annular valve seat in the form of a lower stepped portion in the cap member, a cylindrical retainer secured to the outer periphery of the seal member and having an annular flange facing to an upper stepped portion in the cap member, an annular lip of elastic material integral with the flange of the retainer, and a spring loading the retainer toward the upper stepped portion.

Abstract: The tandem master cylinder is provided with an equalizer device comprising a plunger mounted intermediate two chambers which are respectively connected to the two cavities of the master cylinder. At least one of the ducts connecting the master cylinder and the equalizer device is formed with a constriction slowing down the flow of brake fluid so as to permit a pressure buildup in one of the braking circuits, in case of failure of the other circuit, since the very start of the pedal stroke.

Abstract: An improved electro-pneumatic monitor for double safety valves controlled by solenoid-operated pilot valves. The monitor comprises a relatively short spool centrally held by oppositely disposed captive springs. The sensing passages are provided with relatively small orifices which help to de-sensitize the monitor. The resulting construction is resistant to shifting in response to minor double valve irregularities which otherwise could create undesired lockout conditions.

Abstract: In a fluid reservoir for a brake master cylinder, a cap is coupled over the upper opening of a reservoir casing, and an extendable diaphragm seal member is coupled in a fluid-tight manner within the casing to subdivide the interior space of the casing into upper and lower chambers. The cap is provided at its center with a vertical rod extending into the casing and having a pair of axially spaced recesses at its intermediate portion, the seal member is provided at its inner periphery with an annular valve part movable along the intermediate portion of the rod and cooperating with the recesses to permit the flow of air to and from the lower chamber, and the valve part is normally retained between the recesses to close the lower chamber.

Abstract: In the gas shortage detection device of a piston-type hydropneumatic accumulator, a control rod slidably mounted in the cylinder head on the gas side is displaced under the action of the thrust exerted by the piston when this latter comes closer to the cylinder head than a predetermined distance. A flexible motion-reversal coupling element such as an inextensible cord which works in traction and has a predetermined dead range of travel is placed between the piston and the sliding rod.Correct performance of the detection device can thus be checked by partial draining of the oil compartment, the detection device being triggered into operation when the piston comes close to the bottom end of the cylinder.

Abstract: A sealed type fluid reservoir in which a valve member is incorporated in a main cap which is coupled with an upper end of a casing. The pressure in the interior of the casing is maintained at atmospheric level by the valve member despite pressure variation in the interior of the casing.

Abstract: A resilient seal cap is coupled over an upper opening of a reservoir casing to define an interior air space with the upper surface of brake fluid in the casing. The seal cap is formed integral with a first annular lip co-operating with the inner wall of the casing to provide an inlet check valve permitting the flow of air into the interior air space and with a second annular lip co-operating with a valve plate secured to the center of the casing to provide an outlet check valve permitting the flow of air out from the interior air space to the exterior.

Abstract: A device comprising two oil reservoir tanks communicating with the two respective oil-hydraulic chambers of a tandem type master cylinder and also with each other through an upper and a lower interconnecting oil passage. One of the two tanks has a top opening for oil filling use and normally closed with a vented cap while the other tank is closed at the top and provided therein with an oil level detector means which comprises a stationary reed switch connected with an appropriate external alarm circuit and a permanent magnet vertically movable with the oil level in the tank to close the reed switch as the volume of oil stored is reduced to a predetermined minimum. With the device, even if one of the two oil-hydraulic lines connected with the master cylinder fails to function due to oil leakage, the other line can properly function without any pressure failure as, in the associated tank, a predetermined minimum volume of oil remains on account of the height of the lower oil passage.

Abstract: In a sealed fluid reservoir for a hydraulic brake master cylinder, inlet and outlet check valves are compactly assembled with a reservoir cap to constantly seal brake fluid stored in the reservoir against the surrounding air. The inlet and outlet check valves are selectively opened in response to rise or drop of the level of fluid in the reservoir to ensure smooth fluid supply to the brake master cylinder.

Abstract: A master cylinder having an indicator activated by either a low level fluid condition in a reservoir or any operational pressure imbalance between first and second fluid distribution systems of a master cylinder to inform an operator of an adverse condition which could affect braking.

Abstract: A fluid motor having a housing with a stepped bore for retaining a first piston and a second piston. A sleeve is located in the stepped bore to permit the first piston and the second piston to be of substantially the same diameter. A plug attached to the housing holds the sleeve in the stepped bore. A spring attached to the sleeve holds the first piston against a stop. The spring acts on the sleeve to create a gap with a shoulder in the stepped bore. The second piston which is connected to the first piston through a linkage mechanism carries a concentric shuttle piston. The shuttle piston is subjected to a first hydraulic pressure created by the first piston and to a second hydraulic pressure created by the second piston. An indicator is connected to the shuttle piston and remains inactive when the first and second hydraulic pressures are substantially equal.

Abstract: A two-circuit master cylinder unit for brakes includes first and second cylinders and first and second pistons slidably received in the first and second cylinders, respectively. The first piston is actuated by an external force for pressurizing hydraulic fluid in the first cylinder. The second piston is exposed to a pressure which depends upon the pressure generated in the first cylinder. A shackle device which couples the first and second pistons to one another, allows a relative axial displacement of predetermined magnitude between the first and second pistons. A switching device is operatively connected to the shackle device and is actuated when the predetermined magnitude of relative displacement between the pistons is reached. A warning device is operatively connected to the switching device and responds when the switching device is actuated.

Abstract: In a hydraulic brake system, a housing includes a brake master cylinder and a reservoir formed therein for containing a supply of brake fluid. A sensor piston in contact with the pressure in the brake master cylinder is connected to an indicator piston. The indicator piston is coaxial with a blind cylindrical indicator bore. The blind bore and indicator piston are in communication with the reservoir at a level below which the brake fluid should not be allowed to recede. When the brake is operated, brake master cylinder pressure urges the sensor piston outward. The connected indicator piston is urged toward the blind bore. If the reservoir contains fluid, the blind bore is filled with the fluid. Fluid lock of the indicator piston therefore occurs before any appreciable indicator piston motion into the blind indicator bore. On the other hand, if the reservoir, and the communicating indicator bore, are empty, the indicator piston is enabled to enter the indicator bore by compressing air therein.

Abstract: A device usable in a brake system including two independent hydraulic lines extending from a dual brake master cylinder to front and rear wheel brakes, respectively. The device is arranged across the two hydraulic lines midway thereof to serve the purposes of adjusting the fluid pressure ratio between the front and rear wheel brakes with a change in ratio of the vehicle load bearing on the front wheels to that on the rear wheels thereby to maximize the overall braking efficiency particularly in hard braking operations and of enabling the brake system to operate even with some fluid leakage, possibly occurring in either of the two hydraulic lines, to brake the vehicle effectively enough while at the same time warning the driver of the fluid trouble. The essential component parts, including a number of cooperating pistons and a valve associated therewith, are accommodated in a single cylinder casing and this structure renders the whole device particularly compact in size and simple in construction.

Abstract: A dual brake system is provided with a master cylinder unit, a pressure regulator valve unit and at least one wheel brake unit. Each unit has two hydraulically independent chambers therein and one chamber of each unit is connected with one chamber of each of the other units to define two independent hydraulic brake units. The ratio between the chamber of one unit to the chamber of the other unit in each unit is identical and is other than unity. An indicator or alarm is operatively connected to the pressure regulator valve unit.

Abstract: A master cylinder for a dual hydraulic braking system has two pistons arranged end-to-end in respective bore sections, each piston having sealing valves which close off communication between front and rear brake circuits and respective reservoirs when displaced by operation of a brake pedal to cause pressurization of respective compression chambers connected to the brake circuits. This invention provides two seals in the inner piston between the two compression chambers and an auxiliary chamber defined between these seals into which small quantities of brake fluid escape in the event of leakage from either compression chamber to give visual warning of such leakage.