Abstract: A damper for a hydraulic pilot valve having a valve body in which a plurality of pressure reducing valves, a rotational shaft, an operation member attached to the rotational shaft and a handling member rotating the rotational shaft are provided. The pressure reducing valves are operated through the operation member by rotating the rotational shaft by the handling member, and the damper is disposed in the valve body and is adapted to apply an operational resistance to the operation member due to a viscous resistance of a fluid having high viscosity.

Abstract: A reverse rotation preventing apparatus for a hydraulic actuator includes a hydraulic actuator for driving an inertia member, a main valve which is switched to a driving position in which a pressure oil is supplied to one of first and second ports of the hydraulic actuator and another one thereof is communicated with a tank and to a neutral position in which the first and second ports are shut off, a relief valve adapted to flow out a pressure oil in the first or second port to the tank at a time when a pressure on the side of the first or second port is higher than a set high pressure, a suction valve adapted to suck the pressure oil to the first or second port at a time when the pressure on the side of the first or second port is negative, and a reverse rotation preventing valve adapted to communicate the first and second port sides with the tanks respectively at a time when the pressure on the sides of the first and second ports is higher than a set pressure which is a pressure lower than the set high pres

Abstract: A damper for a hydraulic pilot valve having a valve body in which a plurality of pressure reducing valves, a rotational shaft, an operation member attached to the rotational shaft and a handling member rotating the rotational shaft are provided. The pressure reducing valves are operated through the operation member, by rotating the rotational shaft by the handling member, and the damper is disposed in the valve body and is adapted to apply an operational resistance to the operation member due to a viscous resistance of a fluid having high viscosity.

Abstract: A hydraulic pilot valve includes a valve body, first, second, third and fourth pressure reduction valves formed in the valve body and respectively having, outlet ports, inlet ports and spools for establishing and blocking communication between the ports, and an operation lever pivotally mounted on the valve body and being movable between a neutral position, a first position and a second position. When the operation lever is in the neutral position, the respective spools of the second and third pressure reduction valves are placed at positions establishing communication between the respective inlet port and outlet port. When the operation lever is in the first position, the respective spools of the first and third pressure reduction valves are placed at positions establishing communication between the respective inlet port and outlet port, and in conjunction therewith, the respective spools of the second and fourth pressure reduction valves block communication between the respective inlet port and outlet port.

Abstract: The object of the present invention is to provide a reversible heat sensitive recording material capable of formation and erasion of images with a clear contrast and capable of retaining stable images with time under the conditions of daily living. A reversible heat sensitive recording material comprising a support and, provided thereon, a normally colorless or light colored dye precursor and a reversible color developer which causes reversible change of color tone in the dye precursor due to the difference in cooling rate after heating, characterized in that said reversible heat sensitive recording material contains at least one specific color erasion accelerator containing a long chain alkyl group.

Abstract: A multiple valve includes first and second valve units respectively having first and second valve bodies. The first and second valve bodies have respective spool bores therein; and a respective spool is inserted in the spool bore of each of the first and second valve bodies. The first and second valve bodies of the first and second valve units also have inlet ports, tank ports, and first and second blocks having mounting holes, the blocks and a respective valve body being fixedly coupled together by means of stud bolts. The first block has a first threaded hole on one side surface thereof for receiving the stud bolt, and a second threaded hole on another side surface thereof for receiving a cover bolt. A pump passage, a main passage and a tank passage extend between the one side surface and the another side surface of the first block, and a stud bolt extends through the second block and is engaged with the first threaded hole.

Abstract: A holder is provided for a remote controller of a karaoke machine. The holder causes the remote controller to be removably held to a handle of a microphone. The holder comprises a portion of an elastic material, such that the portion can tightly fit an outer surface of the handle of the microphone. Further, the holder comprises an approximately C-shaped portion or an approximately ring-shaped portion which matches an outer shape of the handle of the microphone. The remote controller comprises infrared-ray-emitting diodes for emitting a signal in response to a user operating the control buttons to the karaoke machine. A signal-receiving means receives the signal emitted by the signal-emitting means, the signal-receiving means then outputting a relevant signal to the karaoke machine for amplifying a voice input through the microphone, adding accompaniment to the thus-amplified voice and outputting a resulting sound.

Abstract: A hydraulic pilot valve consisting of a pair of pressure-reducing valves, wherein a stopper which can freely adjust maximum control inputs of operating levers (23, 24) of the hydraulic pilot valve is provided to make maximum pilot pressures output from the pair of pressure-reducing valves freely adjustable. Furthermore, in the hydraulic pilot valve, a stopper member for limiting a maximum control input of an operating lever is fixed to the operating levers (23, 24), so that an operating force during a maximum operation of an operating lever is received by the stopper member. Furthermore, in the hydraulic pilot valve, an erroneous operation due to vibrations and the like is prevented by a damper mechanism (50) interposed between a lever fixed to each of the operating levers (23, 24) and a main body (1) of the valve.

Abstract: A pressurized fluid supply system, in which a plurality of pressure compensation valves are connected to a pump discharge line of a hydraulic pump in parallel, and direction control valves are provided at the outlet side of each pressure compensation valve to supply a discharged pressurized fluid from the hydraulic pump to a plurality of actuators. The pressure compensation valves include a check valve portion establishing and blocking communication between the pump discharge line and the inlet port of the direction control valve, and a pressure reduction valve portion for supplying a reduced pressure from the pump discharge line. The check valve portion shifts in a valve opening direction in response to an inlet pressure and shifts in a valve closing direction in response to an outlet pressure. The pressure reduction valve portion has a first and a second pressure chamber.

Abstract: Disclosed is a reversible heat-sensitive recording material comprising a substrate and a recording layer formed thereon, said recording layer comprising a colorless or light-colored, electron-donating dye precursor and a specific electron-accepting compound capable of causing a reversible color tone change of the dye precursor on heating.

Abstract: An operating valve device for supplying fluid under pressure to an actuator comprises: a first hole (3) and a second hole (4) for allowing fluid under pressure supplied by a pump (P) into an inlet port (2) connected with the pump to selectively flow into pressure chambers (B.sub.1, B.sub.

Abstract: A hydraulic valve assembly comprises a valve body defining first and second valve receptacle bores, a fluid pump, a first fluid passage communicated with the fluid pump, a second fluid passage communicated with a hydraulic load, and a third fluid passage communicated with a fluid reservoir. A first valve sub-assembly including a sleeve enclosing a first valve mechanism therein is disposed within the first valve receptacle body for selectively permitting and blocking introduction of the pressurized working fluid. Also, a second valve sub-assembly including a sleeve enclosing a second valve mechanism therein is disposed within the second valve receptacle bore for selectively establishing and blocking fluid communication between the second and third fluid passage means.

Abstract: A hydraulic pilot valve unit constructed with an aim of controlling the flow rate of fluid under pressure in proportion to the stroke of the operating lever, irrespective of the speed of operation of the lever, and adapted for use in supply of pilot fluid under pressure by a pilot fluid actuated type changeover valve or the like arranged to be actuated for switch-over by pilot fluid under pressure. This hydraulic pilot valve unit includes valve spools 23 each being slidably movable between a first position where the pilot fluid under pressure supplied by a pilot pressurized fluid supply pump (27) is allowed to flow into outlet ports (26) formed in the valve body (1), and a second position where the outlet ports are allowed to communicate with a reservoir port (30) formed for drainage purposes.

Abstract: The object of the inventioin is to provide a pilot valve which is compact, prevents erroneous operation, and is inexpensive to manufacture. The pilot valve includes a valve body (1), inlet port (2) and outlet ports (3) formed in the valve body, spools (4) operable to interrupt/establish communication between the inlet port (2) and the outlet port (3), pistons (8) for slidably moving the spools (4), a lever (15), and a disk (14) adapted to transmit movement of the lever (15) and having a downwardly directed spherical recess (23). The valve body has a spherical projection (20) pivotably received in the spherical recess (23). A lever mounting shaft (13) is prevented from rotating about its own axis during operation of the lever.

Abstract: In a pressure control valve having a valve body (1), a pilot poppet (7) is so mounted in the body (1) as to permit/prevent communication between a low-pressure relief port (12) and a back-pressure chamber (5), while moderated and stabilized in its opening operation so as to realize a steady relief flow of the valve, which flow depends on relief-flow properties of a relief poppet (4) so provided as to permit/prevent communication between: a pressure supply port (2); and a relief port (3). A piston poppet (8) is slidably mounted in the relief poppet (4) to extend to the back-pressure chamber (5). A cross-sectional area of the piston poppet (8) is larger than an opening area of a seat portion (6a) of a passage (6) in which the pilot poppet (7) is inserted.

Abstract: A self-excited inverter circuit primarily includes a main transformer two switching elements e.g. the first and second (FET) switching elements, wherein capacitors at both ends of said first FET are charged during a time T.sub.1 -T.sub.2 when said first FET is turned off, and the voltage V.sub.g1 across said first FET is clamped by a charge voltage V.sub.c1 and then, a voltage V.sub.gs is applied across the gate and the source of said second FET for electrical continuity to cause the voltage to be clamped. The clamped state is maintained from T.sub.1 to T.sub.2, the saturation reactor is saturated at time T.sub.3, and V.sub.gs, which has been negative, starts to change toward O, thereby causing the first FET to change to ON; V.sub.q falls towards VPi at TP3 and further towards zero point. Thus, the voltage V.sub.q2 changes to zero to cause V.sub.gs of the second FET to become zero and the second FET to be shut off. When said voltage V.sub.q2 is clamped to a fixed value, a high -V.sub.