Abstract: Production and utilization of model mouse, in which human hematopoietic tumor cells can be grown, expressing symptom of human hematopoietic tumor, and can be used in the screening of anticancer drugs for human hematopoietic tumor. The invention provides a new method to produce model mouse for human hematopoietic tumor, including engraftment of human hematopoietic tumor cells into NOG (NOD/Shi-scid, IL-2R? KO) mice.

Abstract: A pressure device control apparatus including a pressure source having a pump, and an accumulator connected to the pump and a pressure device, and a pressure detector for detecting the pressure in the accumulator; a normally-closed type solenoid valve interposed between the pressure device and the accumulator or a fluid tank; and a control unit having a drive control device for outputting a driving signal indicative of a command to operate the pump in response to a detection pressure detected in the pressure detector becoming equal to or less than a first predetermined pressure and a drive stopping signal indicative of a command for stopping the operation of the pump in response to the detection pressure becoming equal to or more than a second predetermined pressure which is higher than the first predetermined pressure.

Abstract: In an accumulator in which a peripheral edge of a bladder dividing the interior of a shell into a gas chamber and a liquid chamber is attached to the shell, the radius of curvature of an inner wall of the shell defining the gas chamber is larger than that of an inner wall of the shell defining the liquid chamber. This construction ensures that the diameter of the bladder can be relatively increased, the deflection of the bladder with a variation in pressure in the gas chamber and in the liquid chamber can be increased, and the radius of curvature of a curved portion of the peripheral edge of the bladder can be increased, there by contributing to an overall improvement in the durability of the bladder.

Abstract: A hydraulic braking pressure control device which includes a bottomed cylindrically-shaped cylinder body, a free piston slidably received in the cylinder body to define a first control chamber leading to a first brake device between the free piston and a closed end of the cylinder body, a control piston slidably received in the cylinder body to define a second control chamber leading to a second brake device between the control chamber and the free piston, and a positioning control device capable of controlling the axial position of the control piston. The first and second control chambers are independently connected to first and second hydraulic braking pressure supply systems through cutoff valves capable of being switched-over between a connecting state and a disconnecting state.

Abstract: A bladder-type accumulator includes a hollow housing having an inner wall surface including a cylindrical surface of a predetermined width, a sheet-like elastically flexible bladder disposed in the hollow housing and dividing an interior space of the hollow housing into a first fluid chamber and a second fluid chamber and a holder which holds a peripheral edge of the bladder against the cylindrical surface of the hollow housing. The peripheral edge of the bladder is shaped such that a relatively large pressure will be applied to at least a partial annular area, having a predetermined width, of the bladder along the peripheral edge thereof.

Abstract: A fluid pressure booster device includes a booster body, a control piston in the booster body for forward and rearward movements to define a boosting chamber between the control piston and a rear surface of a master piston of a master cylinder, a valve piston in the control piston for forward and rearward movements and communicating at its front face with the boosting chamber, a reaction piston in the control piston for forward and rearward movements and connected to an operating member, the reaction piston defining a reaction chamber between itself and a rear face of the valve piston, a stroke accumulator having an accumulation chamber connected to the reaction chamber, an inlet valve disposed between the control piston and the valve piston and interposed in a flow passage extending between the boosting chamber and a fluid pressure source, the inlet valve being closed when the valve piston is retracted and opening when the valve piston advances, and an outlet valve disposed between the control piston and the

Abstract: A hydraulic booster for a master cylinder in which an inlet valve is interposed between an output pressure chamber at the back of the booster piston and an input pressure chamber connected to a pressure source. Advance of the valve piston opens the inlet valve. An outlet valve between the output chamber and an outlet chamber connected to an oil tank closes at advance of the valve piston relative to the booster piston. The booster chamber is exposed to a rear of a master cylinder operation piston. The valve piston oil feed passage connects input pressure chamber with booster chamber at opening of the outlet valve. The reaction chamber at the front surface of the booster piston is reduced in volume with the advancing movement and is connected to an accumulator making it possible to smooth initial operation of the master cylinder and reduce booster system size.

Abstract: In a hydraulic pressure booster comprising a booster piston slidably fitted in a booster cylinder coupled to a rear end of a master cylinder, the piston having at a leading end thereof an output rod abutting against a rear end of a master piston slidably fitted in the master cylinder, an inlet valve interposed between an output hydraulic oil chamber defined to face a back surface of the booster piston and an input hydraulic oil chamber leading to a hydraulic pressure supply source, the inlet valve being opened in response to an advancing movement, relative to the booster piston, of a valve piston connected to an operating member and slidably fitted in the booster piston, an outlet valve interposed between the output hydraulic oil chamber and an outlet chamber leading to an oil tank, said outlet valve being adapted to be closed in response to the advancing movement of the valve piston relative to the booster piston, and a reaction mechanism provided between the valve piston and the output rod for transmitting

Abstract: A hydraulic booster device comprises a booster cylinder coupled with a rear end of a cylinder body of a master cylinder, a booster piston slidably received in a piston guide mounted in the booster cylinder and spring-biased in a retreating direction, a valve piston connected to an operating member and slidably received in the booster piston, an output hydraulic pressure chamber defined to face a back of the booster piston, an input hydraulic pressure chamber leading to a hydraulic pressure supply source, an inlet valve interposed between the input and output hydraulic pressure chambers and opened in response to the advancing operation of the valve piston relative to the booster piston, an outlet valve interposed between the output hydraulic pressure chamber and an outlet chamber leading to an oil reservoir and closed in response to the advancing operation of the valve piston relative to the booster piston, and a booster chamber facing a back of the operating piston and defined between the operating piston and

Abstract: A pressure switch wherein the interior of a casing is divided by a partition into a fluid chamber fed with a fluid the pressure of which is to be detected, and a working chamber in which a switch mechanism is housed. A rod extends slidably through the partition, provided at its one end with a pressure-receiving portion which is adapted to receive a fluid pressure in the fluid chamber, and projecting at the other end portion thereof into the working chamber so as to change the switching mode of the switch mechanism in accordance with displacement, which occurs due to a fluid pressure applied to the pressure-receiving portion, of the rod to the end thereof which is on the side of the switch mechanism. Springs urge the rod towards the fluid chamber. The fluid chamber is further provided therein with a first spring member the force of which constitutes a part of the desired force of the rod-urging spring.

Abstract: A hydraulic pressure source device for supplying an actuating hydraulic pressure to an automotive booster, having an accumulator and a hydraulic pump, the pump being interposed in a low-pressure oil passage leading from the control valve of a hydraulic power steering device to an oil tank. In the oil passage is also interposed an electromagnetic valve which is adapted to be opened and closed under control of an intermittent actuator which intermittently energizes the electromagnetic valve when sensing a pressure in the accumulator below a preset level. The pump is actuated by the hydraulic oil which is discharged into the low-pressure oil passage after having actuated the control valve through intermittent opening and closing operation of the electromagnetic valve to replenish the accumulator with the hydraulic pressure.

Abstract: An antilock braking system and associated method for a four wheel automotive vehicle having front left and right wheels and rear left and right wheels with a determined weight distribution of the vehicle on the front and rear wheels, each wheel having a respective brake cylinder adapted for applying braking pressure to the wheel in response to pressure fluid supplied from a master cylinder. The supply of pressure fluid from the master cylinder to the brake cylinders during a braking operation is controlled in accordance with the weight distribution of the vehicle on the wheels to enable the front and rear wheels normally to undergo incipient wheel slip at substantially the same time. A fluid pressure regulating unit relieves the fluid pressure transmitted to the respective brake cylinders of the four wheels of the vehicle all at the same time when one of the two front wheels rotates at a higher circumferential speed than the other front wheel and indicates incipient wheel slip.

Abstract: A braking oil pressure control device for a hydraulically operated anti-skid brake system comprising a pair of serially aligned first and second cylinder chambers defined in a cylinder body on the opposite sides of a partition wall. The first cylinder chamber is divided by a brake piston on the opposite sides thereof into a first brake chamber communicating with a brake master cylinder and a second brake chamber communicating with a wheel brake such that when the pressure in the first brake chamber is pressurized under the action of the master cylinder, the brake piston is moved to pressurize the second brake chamber for actuation of the wheel brake. A control piston is slidably received in the second cylinder chamber and cooperates with the partition wall to define a control chamber communicating with an anti-skid brake control hydraulic circuit.

Abstract: A master cylinder apparatus of a type of wherein a master cylinder which is in communication through a connecting port with an oil reservoir on its upper side. A piston is provided having at its front and rear surfaces respective elastic cups, whereby the piston may be pushed to advance against the action of a spring on its front side by a push rod. The piston comprises a front main piston and a rear subsidiary piston connected thereto, and is further defined by an axially extending return port communicating between front and rear oil chambers and with a check valve interposed in the return port arranged to be closed by the action of a releasable spring supported by a stopper at the rear surface, during advance motion of the piston.

Abstract: A skid prevention method for reducing braking torque during a wheel lock while braking, using a main control system of an anti-skid brake device regardless of the brake input by the driver. When wheel lock is overcome, reduction of braking torque ceases. When wheel lock lasts more than a preset period without reduction in breaking torque, even when wheel lock results from failure of the main control system, the braking torque is reduced for a preset period through an auxiliary system. If the main control system reduces the braking torque for a period longer than a preset time, braking torque reduction by the main control system may be nullified, and when wheel lock lasts longer than a preset period, the braking torque may be reduced by the auxiliary control system for the preset period. An anti-skid device for carrying out this method has a brake for applying the braking torque to the wheels, a main control system for controlling the brake to reduce braking torque in case of wheel lock.

Abstract: A vehicular anti-skid brake device comprising a hydraulically-operated braking device, an anti-skid hydraulic system for automatically controlling the braking force of the braking device relative to the wheels, and a valve responsive to brake oil pressure for annulling malfunction of the anti-skid hydraulic system when braking is not applied. The braking device comprises a brake oil chamber for generating a braking force and a control oil chamber for generating an anti-braking force against the braking force when the latter is excessive. The control oil chamber receives control oil pressure generated by a control oil pressure generating source and is under control of the anti-skid hydraulic system when braking is applied.

Abstract: An anti-skid braking system for a vehicle comprising a brake unit actuated by pressure generated in a master cylinder by driver actuation and a hydraulic control circuit for hydraulically controlling the actuation of the brake unit to reduce the braking action of the brake unit when an excessive braking force is applied by the brake unit to the brakes of the vehicle wheels. The hydraulic control circuit includes an output section to which a safety valve is connected for releasing the oil pressure when the pressure in the hydraulic control circuit is supplied for a period exceeding a predetermined time.

Abstract: A device for detecting angular acceleration of wheels comprising a first member integrally rotating with a wheel, a second member mounted on the first member through a resilient member so that the second member may be rotated relative to the first member. A mechanism is provided for detecting relative rotation between the first member and the second member. A control mechanism is provided for the wheel for controlling the relative rotation between the first member and the second member so as not to actuate the relative rotation detecting mechanism when the magnitude of angular acceleration of the wheel in one direction or the other is less than a predetermined magnitude.