Abstract: A hydraulic circuit includes a pump driven by a motor, an inverter for controlling the motor, and an accumulator. The inverter controls rotational speed of the motor such that the pump always discharges hydraulic fluid at a fixed flow rate, which is the sum of an average necessary flow rate and an adjustment flow rate. The accumulator operates, when the fixed flow rate and a necessary flow rate differ, in order to accumulate or discharge the hydraulic fluid to thereby secure the necessary flow rate.

Abstract: A screw comprising a first member having a plurality of alternating first thread ridges and first thread grooves, a ridge width of the first thread ridges being larger than a groove width of the first thread grooves at a measurement diameter of the first member. The measurement diameter is determined by calculating a pitch diameter of a hypothetical member having a plurality of hypothetical thread grooves and hypothetical thread ridges, with the hypothetical thread grooves being identical to the first thread grooves, and with the hypothetical thread ridges and the hypothetical thread grooves having identical, but opposite, profiles, and with the measurement diameter being identical to the pitch diameter of the hypothetical member.

Abstract: An accumulator (ACC) in which a container main body (1) and a closure member (5) are screw-joined together. A reverse-buttress internal thread or an internal thread having an included angle of 90 degrees is used as an internal thread of the screw-joined portion. The reverse-buttress internal thread is formed in such a way that the inclination angle (?) of a clearance flank of the buttress internal thread is the inclination angle (?) of a reverse pressure flank (20A) receiving a load, the inclination angle (?) of a pressure flank is the inclination angle (?) of a reverse clearance flank (2B). The internal thread having an included angle of 90 degrees is formed in such a way that inclination angles (?),(?) of both flanks are equal and the included angle (?) is about 90 degrees.

Abstract: As to a weaker screw between the internal screw and the external screw, the width of a thread ridge of an internal screw and an external screw which mutually mesh in the position of its standard pitch diameter is formed greater than a width of a thread groove of a mating screw, thereby displacing the pitch diameter. This prevents failure of the weaker screw when under a load.

Abstract: A receiving portion (11) having a pressure receiving-surface (11F) is provided in the through hole (10) of a container body (1), wherein the pressure-receiving surface has a tapered pressure-receiving surface (11A) and an outer receiving-pressure-regulating R(rounded) surface (11B) continuous to the forward end of the tapered pressure-receiving surface (11A). A supply/discharge tube (13) being inserted into the through hole is provided with a flange portion (14) having a pressurizing surface (14F) which is provided with a tapered pressurizing surface (14A) coming into face-contact with the tapered pressure-receiving surface.

Abstract: A mounting flange is formed at the opening of the bladder formed into the shape of a bag from elastic material such as rubber; and a thin wall section is formed to prevent stress concentration near the base of the mounting flange.

Abstract: An O-ring mounting groove has a bottom surface, which is formed as a recess whose section has an arc-like configuration so as to prevent concentration of stress. A backup ring, which is to be fitted into this O-ring mounting groove, has a lower surface whose configuration is in conformity with the bottom surface of the O-ring mounting groove, so that, when an axial force is applied to the backup ring, it is pushed outwardly.

Abstract: An expansion-type fuse safety device for an accumulator has a fuse packing having a through hole of a diameter smaller than the outside diameter of a sealing portion of the flanged valve casing. The valve casing is inserted into the through hole of the fuse packing so as to project outward from a pressure vessel through a passage hole formed in the pressure vessel. A tightening nut is screwed to the projecting end of the valve casing so that the fuse packing is pressed between the inner surface of the pressure vessel and the flange of the valve casing.

Abstract: An apparatus for supporting a diaphragm of an accumulator comprises a support ring which has a sectional form with a circular arc-shaped inner edge and a linear outer edge and which has an elastic layer provided on the side of the outer edge, the support ring being fitted into a groove provided in a flange of the diaphragm and inserted into a container body until it is stopped by a stage portion thereof so that the gap between the support ring and the container body is sealed by the elastic layer.

Abstract: An internal-pressure-bearing female screw adapted to be applied with a varying composite load due to variation of an internal pressure, in which the thread contact heights of the female screw are formed so as to be successively lowered along the direction of an applied tensile load, whereby the bending moments per unit length at the bottom of valleys of the respective female screw threads are equalized to reduce the maximum bending moment and the bending moment amplitude.

Abstract: A thread joint to be subjected to the fluctuating load having a thread to be subjected to the tensile load from which a thread crest contact surface is cut off from the threads thereof in the direction of the tensile load, and the contact height of the same is lowered with respect to the other portion. Therefore, the maximum bending moment per unit area generated at the root of the threads is uniformed and the peak bending moment per unit area is reduced.

Abstract: A guide projecting into a bladder is provided on a plug of a vessel body. A cup-shaped sensor is slidably provided on the guide, and an element for actuating a switch is provided on the cup-shaped sensor. The cup-shaped sensor is caused to slide along the guide by the bladder deformable in accordance with change in the pressure of liquid within the accumulator, so as to actuate the switch.

Abstract: An accumulator of the type that an interior of a vessel main body provided with a feed/discharge port or ports is partitioned into a gas chamber and a liquid chamber by means of a bladder, an inner tube having communication holes is disposed between the feed/discharge port or ports and the bladder, and valve bodies for opening and closing the communication holes are provided on the inside of the inner tube; the communication holes are inclined with respect to the axis of the vessel main body so that liquid passing through the communication holes may collide obliquely against the valve bodies.

Abstract: An accumulator provided with an insert, in which a vessel main body having a feed/discharge port or ports is partitioned into a gas chamber and a liquid chamber by means of a bladder, and an insert projecting into the bladder is disposed, whereby a volume of the gas chamber is reduced.

Abstract: In a bladder supporting device in an accumulator of the type that a flange of a bladder is pinched by a vessel main body having a step formed on its inner wall surface and a hook-shaped press edge of a lid member, and a support ring fitted in an annular groove on the outside of the flange is engaged with the step; the support ring is formed by folding back an inside half of an annular sheet metal under an outside half thereof so that an inner circumferential surface of the support ring may be of circular arc shape in vertical cross-section.

Abstract: A bladder is disposed coaxially within a cylindrical container main body, a holder projecting into the bladder is provided on a top wall plate of the container main body, a sensor opposed to a bottom portion of the bladder and positioned within a moving locus region of the bottom portion or a deformable portion of the bladder is disposed at the bottom portion of the holder, and thereby, when the bladder deforms in response to variation of a liquid pressure the bottom portion of the bladder or the deformable portion of the bladder would actuate the sensor.

Abstract: In an NC-lathe comprising a thread touch sensor provided with a touch portion to be brought into contact with an effective radius/diameter portion of a screw thread, an automatic measuring device electrically connected to the thread touch sensor, and an automatic correction device connected to the automatic measuring device; an effective radius or diameter of a screw thread is measured by bringing the touch portion of the thread touch sensor into contact with an effective radius/diameter portion of the screw thread, the measured dimension is compared with a desired dimension, and when a difference is produced between the respective dimensions, the NC-lathe is controlled by correcting an amount of machining by means of the automatic correction device.

Abstract: A temperature responsive fusible packing is inserted in a ring shaped space defined between the lower face of a bolt head and the bottom face of a recessed portion formed on the supply port of a gas chamber of an accumulator and then the bolt is tightened, so that the fusible packing can act as a packing which blocks both the gas passage and the inner passage formed through the shank of the bolt. In the event where, the temperature responsive fusible packing should melt due to a fire or the like, since the thus fused packing is expelled outside the device through a gap formed between the wall face of the recessed portion and the outer periphery of the bolt head, a vacant space would be formed there to expose the inner passage to an open air and allows the gas in the gas chamber to be discharged outside.

Abstract: In an in-line type accumulator of the type that on the inside of a pressure vessel there are provided a cylindrical isolating member and an inner tube having communication holes in succession in a concentric manner, a diameter of a central portion of the isolating member is made larger than a diameter of the portions on the opposite sides of the central portion, and thereby constricted portions having a U-shaped longitudinal cross-section are formed on the opposite sides of the central portion.

Abstract: In a pulsation absorbing device which comprises inside its cylindrical pressure vessel, a cylindrical resilient diaphragm, an inner cylinder formed with a plurality of communicating holes on the outer surface thereof, and the resilient diaphragm and the inner cylinder are disposed being concentrical with the cylindrical pressure vessel, in addition, one or more resilient valve shoes of arched shape in its transverse cross section disposed along the outer surface of the inner cylinder and at the location corresponding to the communicating holes and is capable of being placed in a raised or lowered position, the improvement resides in that the resilient valve shoes are composed of a plurality of thin membranes laminated with each other, so that the valve shoes not only can be readily deformed elastically responsive to any possible pressure variation, but also can secure strength sufficient to withstand the fluid pressure when they are positioned to cover and close the aforesaid communicating holes.