Abstract: A sealing boot of elastomeric material for hermetically closing an annular opening between support and movable members in relatively reciprocable relationship, the sealing boot including a tubular bellows portion which is integrally formed at the opposite ends thereof with a pair of cylindrical sealing portions respectively attached to the support and movable members, and wherein one of the cylindrical sealing portions is formed with a cylindrical sealing surface to be tightly in contact with the outer circumference of either the support or movable member and is further formed at its inner end with an annular flank which is curved radially away from the cylindrical sealing surface.

Abstract: A hydraulic pressure control valve for a dual-circuit brake system of a vehicle. In this control valve a pair of valve pistons for controlling the braking hydraulic pressure delivered to each of rear wheel brakes are disposed in a housing parallelly and imparted with biasing force directed inwards of the housing by one biasing device. The biasing device is assembled or set within a cover of cup-shape such that the biasing device has been given a preload substantially equal to a biasing force necessary for the control valve before the cover is fixed to the valve housing. The biasing device includes a swingable guide rod attached at one end thereof to the cover with a pivot pin, a sliding member slidably fitted on the guide rod, and a compression spring disposed between the sliding member and a free end of the guide rod for biasing the sliding member toward the pivoted end of the guide rod.

Abstract: A brake booster of the stroke-enlarging type which includes a power piston disposed in a casing for being actuated by a difference in pressure on opposite sides thereof. The brake booster includes a transmission device in the form of a ball and ball retainer which are biased by a spring while the ball is retained between a surface of the power piston and a control piston. The ball and ball retainer are limited in movement by a stopper coupled to the power piston. The ball and ball retainer forming the transmission device are advanced in response to the spring bias by the power piston and are operated such that when a brake clearance has been extinguished and a reactionary force from the output member becomes larger than the preload of the spring, the reactionary force blocks the advance of the ball and ball retainer so that the reaction force is partly transmitted to the control piston with a resultant reduction of the reactionary force transmitted to the power piston.

Abstract: A brake booster of stroke-enlarging type which includes a casing, a power piston so disposed as to divide the interior of the casing into two chambers for being actuated by the difference of pressure in the two chambers, a control piston, containing therein a valve mechanism for controlling the difference of pressure in the two chambers and a transmission mechanism for transmitting an input of an input member to an output member, being coaxially fitted into a central bore of the power piston relatively movably thereto and a reaction lever, which is abutted at an output portion in the middle thereof by the output member, receiving output of the transmission mechanism and output of the power piston respectively as an input at a first input portion and a second input portion thereof located on either side of said output portion in the middle, whereby a greater stroke can be obtained at the output member than a stroke input at the input member.

Abstract: A brake booster of stroke-enlarging type which includes a power piston disposed in a casing for being actuated by a difference in pressure on opposite sides thereof, a control piston, having therein a control valve for controlling the difference in pressure, being coaxially fitted into a central bore of the power piston relatively movable thereto and a reaction lever, which is abutted at an output portion in the middle thereof by an output member, receiving the output force of the power piston and the output force of the transmission mechanism respectively as an input force at a first input portion and a second input portion thereof located on either side of said output portion, whereby a greater stroke can be obtained at the output member than a stroke applied at an input member.

Abstract: A brake booster of stroke-enlarging type which includes a power piston moved in accordance with the difference of pressure on opposite sides thereof, a control piston having therein a control valve for controlling the pressure difference and slidably fitted in a central bore of the power piston, an anti-backdown transmission mechanism disposed between the two pistons, a reaction lever abutted at an output portion thereof on an output member and, at a pair of input portions located on opposite sides of the output portion, on the control piston and the anti-backdown transmission mechanism respectively, and a return spring backwardly biasing the power piston.

Abstract: A brake booster of stroke-enlarging type wherein the brake feeling is improved. The brake booster includes a casing, a power piston disposed in said casing so as to divide the interior of the casing into two chambers for being actuated by the pressure difference in the two chambers, and a control piston having a built-in control valve for controlling the pressure difference due to the operation of an input member. The power piston is so disposed as to be relatively movable for a predetermined distance with respect to the control piston and able to be advanced at the initial stage of the braking operation relative to the control piston at a stroke, independently of the amount of advancement of the input member, for the predetermined distance in order to give an output member a larger output stroke than stroke input.

Abstract: A disc brake of ventilated disc rotor type wherein air is positively introduced into the air passages formed in the disc rotor. In the dust cover of this type disc brake an air introducing hole is formed. On the outside of the dust cover an air collector is disposed for positively collecting and introducing the air flowing in the vicinity of the dust cover. On the inside of the dust cover an air guide is disposed for guiding the air taken through the air introducing hole as far as the entrance of the air passages in the disc rotor.

Abstract: A brake booster of the stroke enlarging type wherein a power piston operated by the pressure difference existing on opposite sides thereof is moveable relative to a control piston provided with a control valve for controlling the difference of the pressure, and the power piston and the control piston are engageable to be immovable relative to each other by means of a locking member after the pressure difference has reached a predetermined value. The power piston is so constructed as to be able to advance a larger distance than the control piston, while the pressure difference is small, to move the output member by a larger amount in comparison to a small amount of advancement of the input member of the booster.

Abstract: A braking hydraulic pressure control unit for a motor vehicle including a differential-acting piston having a plurality of pressure bearing portions facing an inlet compartment and an outlet compartment communicating with a master cylinder and rear wheel cylinders, respectively, of a vehicle braking system. The differential-acting piston is formed with shoe clearance compensating piston segments operative to reduce an inflow of a braking fluid into a spherical valve chamber at initial stages of brake application whereby unfavorable influences which would otherwise be exerted by the size of shoe clearances on a spherical valve at initial stages of brake application can be prevented.

Abstract: A disc brake used in a car wherein a friction pad is urged onto the disc surface to restrain the movement of the disc, which disc brake, for facitating the mounting of the friction pad, is provided with (1) a backing plate of the friction pad having a notch sandwiched by two projection portions, an upper, and a lower which is smaller than the upper in projected length, on opposite upper end corners of the pad for being fitted into by a guide rail formed on a stationary member in order to allow the friction pad to slidably move in a normal direction to the disc surface; (2) a guide rail having a recess on one part thereof for allowing the lower projection portion formed smaller on the lower side of the notch to pass in a normal direction to the guide rail but not allowing the upper projection portion formed larger on the upper side of the notch to pass in the same direction; and (3) an anti-rattle spring comprising a flat body portion, an upper holding down pawl, a flange portion extending perpendicularly from

Abstract: A drum brake used in a vehicle generally includes a backing plate secured to a non-rotatable member of a wheel shaft; a pair of brake shoes slidably attached to the backing plate; a wheel cylinder disposed between each end portion of the brake shoes where they are closely positioned to each other; and a substantially U-shaped return spring to be engaged with each web portion of the brake shoes at the extreme ends thereof for biasing both in a mutually approaching direction. The U-shaped return spring in this invention is characteristically provided with, at each end portion thereof, where the same is engaged with each web portion of the shoes, a notch whereinto the web portion is to be fitted for securely positioning the return spring.

Abstract: Fluid pressure operated disc brakes of a vehicle of the kind having a stationary member adapted to be secured to a non-rotatable part of a wheel assembly, a movable member on the stationary member, fluid pressure operated brake actuator incorporated into the movable member, a brake pad on one side of the friction disc slidably guided by the stationary member and directly responsive to the fluid pressure operated brake actuator, and a second friction pad on the opposite side of the fraction disc. A deformable resilient spacer is interposed between the stationary member and the movable member for resiliently mounting the movable member on the stationary member in restorably and axially shiftable relation to the stationary member due to the deformation of the resilient spacer.

Abstract: A dual fluid reservoir for a tandem master cylinder includes front and rear fluid chambers communicated to each other and comprises a lateral partition provided within the casing of the reservoir to block free fluid communication between the two chambers after the fluid level within the chambers drops below a lowest level defined by the lateral partition, and an annular partition provided on the lateral partition to form a float chamber therein, the annular partition being higher than the lateral partition in a predetermined length and including a pair of recessed portions corresponding to the lateral partition to permit fluid flow from the two fluid chambers into the float chamber. Thus, a magnetically operable switch device is mounted on the casing between the two chambers to actuate a warning device and a float is disposed within the float chamber for vertical movement and operatively connected to the switch.

Abstract: A fluid reservoir is partitioned by a diaphragm into a liquid phase portion and a vapor phase portion with the diaphragm being moved in accordance with the liquid level in the liquid phase portion of the reservoir. An operating rod mounted to move with the diaphragm is engaged by sensing means which operate to produce a signal indicative of liquid level in response to the position of the operating rod. The operating rod may be composed partially of electrically conductive material and partially of electrically nonconductive material in order to open and close an external electrical signal circuit in accordance with its position relative to the level of liquid within the reservoir.