Abstract: An object of the present invention is to provide a semiconductor wafer having a front and a back surfaces polished so as to have different glossiness from each other, yet with a lower cost. The glossiness of the front surface and the back surface can be selected arbitrarily. In a double-sided polisher with no sun gear, silicon wafers W are inserted in respective holding holes 11a of a carrier plate 11. The wafers W are placed with their back surfaces facing up. An expanded urethane foam pad 14 is pressed against the back surfaces of the wafers W and a non-woven fabric pad 15 is pressed against the front surfaces of the wafers W. A carrier holder 20 and thus the carrier plate 11 are then driven to make a circular motion associated with no rotation on their own axes within a horizontal plane while supplying a slurry to the wafers W from an upper surface plate 12 side.

Abstract: A pneumatic booster includes a valve mechanism for introducing atmospheric air into a variable-pressure chamber in accordance with the movement of a plunger, propelling a power piston due to differential pressure generated between the variable-pressure chamber and a constant-pressure chamber and transmitting force by which the power piston is propelled through a valve body to an output shaft. The valve mechanism includes a poppet valve mechanism including a seal surface capable of abutting against an annular atmospheric valve seat formed in the plunger and a seal surface capable of abutting against an annular negative pressure valve seat formed on an inner surface of the valve body. The annular atmospheric valve seat of the plunger is located in a position forward in a direction of propelling of the power piston relative to the negative pressure valve seat and is substantially aligned with the negative pressure valve seat in an axial direction.

Abstract: A pressure differential operated brake booster includes a housing, a diaphragm assembly adapted to divide the interior of the housing into a constant pressure chamber and a variable pressure chamber, a valve body carried by the diaphragm assembly, a valve mechanism arranged within the valve body and including a plunger connected to an input rod, and a reaction assembly disposed between the plunger and an output rod. The valve mechanism is operable to develop a pressure differential across the diaphragm assembly to transmit its movement to the output rod and feed part of the resulting reaction force back to the input rod through the reaction assembly and the plunger. The reaction assembly includes a front reaction disk and a separate rear reaction disk having a diameter less than that of the front reaction disk and greater than that of the plunger. The front reaction disk is disposed between the valve body and the output rod. The valve body has at its front end a recess to receive the rear reaction disk.

Abstract: A brake booster includes a housing, a partition adapted to divide the interior of the housing into two chambers, and two diaphragms adapted to divide the two chambers into constant and variable pressure chambers. A control valve includes a valve body carried by the diaphragms, and a plunger slidably received in the valve body. The control valve is operatively connected to the variable pressure chambers to develop a pressure differential across the diaphragms to cause the diaphragms to move in response to actuation of an input rod. A reaction disk is disposed between an output rod and the valve body to transmit the reaction of movement of the output rod to the input rod. An adjusting mechanism is disposed between the plunger and the reaction disk and compressible so as to develop a greater degree of pressure differential when a force applied by the input rod exceeds a predetermined level.

Abstract: A booster apparatus of a vacuum type for a brake device has a housing including therein a chamber, a diaphragm for dividing the chamber of the housing into a constant pressure chamber and a variable pressure chamber, an input shaft including a distal end, an output shaft including a proximal end, a plunger which is engageable with the distal end of the input shaft for transmitting force from the input shaft to the output shaft, a reaction disk disposed between the plunger and the proximal end of the output shaft for transmitting reaction from the output shaft to the plunger, and a valve body mounted on the diaphragm. The valve body includes a hole for slidably receiving the plunger, a recess for fixedly receiving the reaction disk and the proximal end of the output shaft which recess is larger than the plunger hole in inner diameter, and an intermediate hole portion disposed between the plunger hole and the recess.

Abstract: A tandem pneumatic booster having a shell body, the inside of which is divided into two, front and rear, chambers by a center shell. Each chamber includes a negative pressure chamber and a working pressure chamber. A valve body is slidably fitted in the shell body and the center shell with seal members therebetween. The valve body is provided with an air passage for communication between the front and rear working pressure chambers. A valve mechanism is actuated in association with an input shaft to introduce atmospheric air into the front and rear working pressure chambers through the air passage so as to apply thrust to front and rear power pistons. The diaphragm of the front power piston has a bead on an inner periphery thereof. The valve body has a groove on an outer periphery thereof. A portion of the air passage which leads to the front working pressure chamber has a main passage portion extending axially in the valve body, and a bypass extending radially outward from the main passage portion.

Abstract: A plunger moved with an input shaft is movably fitted in an axial bore of a valve body made of resin, and a valve mechanism selectively establishes and cuts off communication in a negative pressure passage and an atmosphere passage formed in the valve body according to the movement of the plunger. Also, a pair of radial holes formed to have a circular cross section are provided in the valve body by drilling work, and a plate type stop key formed in a fork shape having two claw branches is mounted by loosely inserting the branches in the radial holes. The stop key limits a movement range of the plunger. Also, a guide portion is formed on an outer circumference of the valve body to guide side surfaces of the stop key. The movement of the stop key is restricted by the guide portion and a step formed in the axial bore of the valve body. Therefore, a smooth operation of the pneumatic booster can be guaranteed.

Abstract: A pneumatic booster for use, for example, in a brake system of a vehicle, and designed so that the overall axial length is reduced without interfering with the operation thereof. The booster comprises a valve body which is movable back and forth between first and second positions in a housing that is divided by a diaphragm with a power piston into front and rear chambers communicated with respective pressure sources, a valve which allows at least one of the front and rear chambers to selectively communicate with the pressure sources which differ from each other in the level of pressure, and a guide which slidably fits on the outer periphery of the valve body. The valve body has a passage one end of which opens on the outer periphery thereof to connect one of the front and rear chambers to the associated pressure source, the opening of the passage being positioned in the axial direction of the valve body so that the guide overlaps the opening when the valve body is at either the first or second position.

Abstract: A pneumatic booster has a housing which includes a forward shell and a rearward shell, and a diaphragm which is installed inside the housing and secured at the outer peripheral portion thereof to the housing. The diaphragm has a bead formed on the outer peripheral portion thereof. The rearward shell has a bead retaining portion which has a bead retaining groove that opens radially outward. The forward shell has an outer peripheral portion. The bead is received into the bead retaining groove across one edge portion of the bead retaining groove and clamped between the groove and the outer peripheral portion of the forward shell. The dimensions of the bead and the bead retaining portion are set so that the inner diameter of the bead is greater than the outer diameter of the edge portion of the bead retaining groove. Thus, the rearward shell and the diaphragm can be assembled together without the need to bend the diaphragm in advance, and the assembly process is correspondingly facilitated.

Abstract: A pneumatic booster comprising a housing, a power piston separating the inside of the housing into a constant pressure chamber and a variable pressure chamber, a valve body attached to the power piston, an output shaft, a plunger slidably received in a bore in the valve body, an input shaft and a valve mechanism in the bore for selectively communicating the variable pressure chamber with a negative pressure source or the atmospheric pressure, the valve mechanism including a valve member mounted on the inner wall of the bore, a first valve seat formed on the inner wall of the bore and a second valve seat formed on the plunger.

Abstract: A pneumatic booster includes a casing, a diaphragm secured to the casing to partition the inside of the casing into a front chamber which is communicated with a negative-pressure source and a rear chamber, a valve body secured to the inner peripheral portion of the diaphragm, a vacuum valve provided in the valve body to allow the front and rear chambers to be selectively communicated with and cut off from each other, an atmospheric valve provided in the valve body to allow the rear chamber to be selectively communicated with and cut off from the atmosphere, an input rod for actuating the vacuum and atmospheric valves, and an output rod adapted to receive the force of displacement of the diaphragm. The atmospheric valve is composed of first and second valve portions provided in series along a communicating passage between the rear chamber and the atmosphere. The first and second valve portions are closed successively in the mentioned order when the atmospheric valve is closed.

Abstract: A pneumatic booster including a housing, a power piston partitioning the interior of the housing into a front chamber and a rear chamber, with the front chamber being connected permanently to a source of a first reference pressure, the rear chamber being selectively communicated with the front chamber and a source of second reference pressure which is higher than the first reference pressure through a valve mechanism, an output shaft receiving the output force from the power piston, and an input shaft receiving an input force for actuating said valve mechanism and receiving a reaction force of the output force. There are provided a device between the output shaft and the power piston for changing the reaction force with respect to the output force on the output shaft, a mechanism for rotating the output shaft around the axis thereof, and a device for preventing the rotation of the power piston relative to the housing at least at the non-actuated condition of the pneumatic booster.

Abstract: A tandem pneumatic pressure booster in a braking apparatus for a motor vehicle, comprising a housing; front and rear movable walls; a center plate; the housing being hermetically closed by front and rear shells; front and rear variable pressure chambers; front and rear referential pressure chambers; a valve body having a control valve therein; a reaction disc containing case; a cylindrical passage member adapted to fit over the barrel of said case; the front movable wall being fixed to the case-passage member assembly, said passage member being provided with a referential pressure chamber communicating passage; and a variable pressure chamber communicating passage, whereby these parts may be formed into a configuration suitable for die casting and for improving mass productivity without deteriorating the differential pressure.

Abstract: A pneumatic booster of the type including a housing, a power piston partitioning the interior of the housing into a constant pressure front chamber and a variable pressure rear chamber, a return spring disposed in the front chamber and biasing the power piston rearwards, a reaction disc mounted on the power piston, an output shaft disposed frontwards of the reaction disc, an input shaft disposed rearwards of the reaction disc, and a valve mechanism associated with the input shaft and controlling the pressure in the rear chamber. A lever is mounted on the front surface of the power piston with radially outer end thereof being biasing against the front surface of the power piston by the return spring and the radially inner end thereof being engageable with the output shaft to transmit at least a part of the output force of the booster from the power piston to the output shaft.

Abstract: A pneumatic booster including a housing, a power piston partitioning the interior of the housing into a front chamber and a rear chamber, with the front chamber being connected permanently to a source of a first reference pressure, the rear chamber being selectively communicated with the front chamber and a source of second reference pressure which is higher than the first reference pressure through a valve mechanism, an output shaft receiving the output force from the power piston, and an input shaft receiving an input force for actuating said valve mechanism and receiving a reaction force of the output force. There are provided a device between the output shaft and the power piston for changing the reaction force with respect to the output force on the output shaft, a mechanism for rotating the output shaft around the axis thereof, and a device for preventing the rotation of the power piston relative to the housing at least at the non-actuated condition of the pneumatic booster.

Abstract: A pneumatic booster of the type including a power piston partitioning the interior of a casing into a front chamber and a rear chamber, a reinforcing rod connected to the casing and extending through the front chamber, the power piston and the rear chamber, and a poppet valve for introducing atmospheric air into the rear chamber and actuated by an input shaft which is slidably mounted on the power piston and extends rearwards out of the casing. A passage is formed in the reinforcing rod with one end communicating permanently with a space into which atmospheric air is introduced through the poppet valve when it is actuated, a cut-off valve is provided for communicating or cutting off the passage in the reinforcing rod, and an air introducing device for introducing atmospheric air into the rear chamber is provided independently of the poppet valve.