Abstract: A piston slidably inserted into a cylinder is reciprocated by fluid pressure such as pneumatic pressure and hydraulic oil and a spring is used to ascend the piston. A spool-shaped pilot valve element is provided to allow a supply-discharge valve disc to take supply and discharge positions, thus fluid pressure being supplied to and discharged from the cylinder. When the supply-discharge disc is actuated to take the supply position from the discharge position, the actuated force (supply position and discharge position) becomes stronger while the supply-discharge valve disc is in operation. When the supply-discharge valve disc is actuated to take the discharge position from the supply position, the back pressure resistance applied to the supply-discharge valve disc become weaker while the supply-discharge valve disc is in operation.

Abstract: In a knockout device which is mounted in a press-machine in order to knock out a punched work plate such as a printed board and the likes from punches through a knockout actuation-plate, cylinder chambers as an oil hydraulic knockout cylinder is formed in the upper portion of a base plate fixedly secured to the underside of a slide and an actuation-plate guide hole is formed in the lower portion of the base plate respectively. The cylinder chambers are disposed at the eccentric positions offset toward the periphery of the actuation-plate hole respectively. The knockout actuation-plate provided in the actuation-plate guide hole is adapted to be driven downwardly protrusively by the pistons provided in the cylinder chambers, and to be linearly guided by the peripheral surfaces of the knockout actuation-plate and of the linear guide boss protruded upwardly from the central portion of the knockout actuation-plate.

Abstract: The present invention relates to a transferring device for dies of presses and work pallets of machine tools and the like. A die transfer car is movable on two parallel rails, one side of the car is provided flanged wheels and the other side of which is provided plain wheels. When the car is stopped by a stopper having a stopper pin provided at the plain wheel side, through a stopping control device, the car is frictionally stopped by the flanges of the wheels and the side face of rails due to rotation caused by the inertia force around the stopper pin.

Abstract: An apparatus for positioning and clamping a transferrable work-clamp pallet on the movable table of a machine tool of vertical or horizontal type. The pallet clamping device is composed of a bed plate on the movable table of the machine tool having transfer rails, guide rails, pallet supporting blocks, positioning devices and clamping devices. The work-clamp pallet is transferred onto the bed plate by its castors rolling on the transfer rails and guided by the guide rails. After high-precision positioning by the positioning devices, the pallet is clamped onto the supporting blocks. Devices are also provided for confirming proper positioning and clamping of the work-clamp pallet and for blowing off chips deposited on the supporting blocks.

Abstract: The present invention relates to a work-clamp pallet used to clamp workpieces on a table of a machine tool to improve the working efficiency of the machine tool. This is achieved by shortening the time for exchanging workpieces on the table and for positioning workpieces on the table along both X and Y axes. A large number of workpieces are positioned on a work-clamp pallet along the Y-axis by the aid of a standard frame secured to a base block and along the X-axis by the aid of positioning stoppers projecting from the standard frame. The workpieces are clamped against the standard frame by clamping devices disposed at least on one side of the standard frame. The positioning and clamping a large number of workpieces on the base block is done outside the machine and, when the machine has stopped a machining over, a work-clamp pallet is transferred onto the table in exchange for that with finished workpieces which is removed.

Abstract: An improved pneumatic-hydraulic driving device for the knockout mechanism associated with the slide of a press-machine wherein the device serves to actuate the knockout mechanism in a controlled manner to provide cushioning motion during punching of the work, and knocking out motion after punching to permit removal of the punched work by a transfer machine, with the device being particularly useful in the fabrication of printed circuit plates wherein the device serves to decrease cycle-time of fabrication and increase quantity of production.

Abstract: A retracting clamp suited for clamping a die or a workpiece, a die of an injection molding machine in particular, is disclosed, wherein a hydraulic cylinder is provided in the rear part of a clamp housing, a clamp block is carried slidably by a gently tapered underside of the front part of its piston rod, and the clamp block is urged forward by a spring so as to drive it for clamping at its extruded position and, when clamping is over, the clamp block is retracted to its retracted position and a piston is urged toward the clamping position as necessary by a spring, and the position of the clamp block is detectable by means of limit switches.

Abstract: A retracting clamp for dies or workpieces, especially for the die of the injection molding machine, whose clamp arm is installed in the chamber of the clamp housing so as to shift its position between an extended position and retracted position. The clamp arm is driven with a wedge connected to the piston-rod of the hydraulic cylinder. A spring enables clamp arm to hold the clamping force in case of hydraulic oil leakage. There is also provided means for retracting the wedge without failure and means for detecting the positions of the clamp arm.

Abstract: A device for exchanging dies for a machine using dies is disclosed, wherein a pair of carriage cars are adapted to be movable in front of a die mounting space between a stationary plate and a movable plate of the machine to which the dies are clamped, transfer means for exchanging the dies between the die mounting space and the carriage car are provided, a main unit of a push-pull device is provided in front of the carriage car independently thereof so that the dies can be changed by this push-pull device between the carriage car and the die mounting space.

Abstract: An auxiliary die conveyor includes a metal support jointed to a bolster and a die carrier including a pair of side plates, the carrier further including a hanging means in its upper tail section, the support metal including a depression adapted to interlock with the hanging means in such a manner as to allow the carrier to rotate in the depression while a lower part of the carrier comes into abutment with the support metal, thereby preventing the carrier from lowering below the level of the bolster.

Abstract: A gas-inlet attachment includes an air-tightly sealed pressure differentiator in the mouthpiece of a gas charger, wherein the pressure differentiator includes a valve-opener slidably and air-tightly connectable to the check valve in the cock with a pressure differentiating space interposed therebetween, thereby enabling the check valve to be biased in its opening direction under the differentiated pressure provided by the pressure differentiator.

Abstract: A die lifter unit comprises a rolled metal section of inverted open-topped rectangular shape which is floatably supported on heavy duty springs in a groove extending along the top surface of the bolster, the section carrying a roller for supporting the die.

Abstract: The bolster of a pressing or punching machine is provided with a hydraulic die lifter unit having a hydraulic system in itself, the die lifter unit including rollers adapted to allow a die to transport smoothly thereon, and being floatably fitted in a groove on the top surface of the bolster.

Abstract: A pressure-responsive valve unit is received in the cavity of a valve assembly housing, the inner end of the cavity being connected with a fluid container. The valve unit includes a main body having a chamber containing a check valve body that is movable toward and away from engagement with a valve seat on the main body, the valve seat facing the check valve body and the inlet end of the cavity, and the main body having passage means communicating fluid from the container to the front end portion of the check valve body. The check valve body is biased into engagement with the valve seat by a spring, the force of which is adjustable with a plug threaded into the inner end of the main body chamber. An outlet bore extends from the outer end of the main body to the valve seat, and the check valve body is engageable by a push rod inserted through said outlet bore.

Abstract: An overload protector for mechanical press comprises a cylinder chamber formed in the mechanical actuating chain of the press, and filled with incompressible fluid; a safety valve which relieves the fluid from the chamber when the chain receives an overload, and which includes a relief route containing a pilot valve part and main valve part in series. The pilot valve part is arranged to close the route at the outlet of the passage penetrating the valve member of the main valve part therethrough, and to be opened by the pressure of the fluid when above the setting pressure for relief. The valve member of the main valve part is arranged to be moved for opening the route by the difference between the pressures acting thereon from both sides connected by the passage when the pilot valve part is opened.

Abstract: A pressure fluid engine of single acting cylinder type has a directional control valve and a master valve with a spool and two valve seats. The spool is formed on a piston rod extending from a piston in the cylinder, the rod passing through a cylindrical disc of the directional control valve. One of the valve seats is provided in the disc to unseal the pilot operating fluid when it cooperates with the spool at a dead point. Another valve seat for the spool is provided in one of the valve chambers of the directional control valve to unseal the pilot operating fluid when it cooperates with the spool at the other dead point. The directional control valve is actuated by means of directional control of a pilot operating fluid with the master valve, in order to reverse the direction of the piston when the piston reaches one of the dead points.

Abstract: A hand-operable takeout valve for temporary attachment to a fluid pressurized container, including a hand-operable main valve and a check valve operable in response to a fluid pressure, wherein the check valve is additionally controllable by hand for co-working with the operation of the main valve.