Abstract: A preparatory working device by which a work piece to be fed to a rack bar forging device is obtained. The device is provided with a die sets for obtaining a diameter reduction at a location of a blank pipe, which becomes a toothed part of a rack bar, while the wall thickness being substantially unchanged or slightly increased. The device is further provided with a die set for reducing a wall thickness at a location of the blank pipe, which becomes a connection part of the rack bar. The wall thickness reduction is one half of the initial thickness, which causes the length of the work piece to be elongated. Then a rack bar forging by a die set is done.

Abstract: Method and apparatus for producing a thin walled tubular product with thickened flange. A first stage metalworking (drawing) of a circular plate material A is done by using a first die set 22 having a conical die 24 and a drawing punch 26 is done in a manner that the end of the blank plate is remained on the conical surface 24-1 of the die, so that a semi-finished tubular product A1 with a inclined flange A1-1 is obtained. Then, a second stage metalworking (drawing) of the semi-finished tubular product A1 is done by a second die set 32 having a shaping punch 34 and a restraint die 36. The semi-finished tubular product A1 is held by the restraint die 36 and the shaping punch 34 is introduced into the semi-finished tubular product A1 for effecting a wall thickness reduction under ironing principle while forming a stepped portion.

Abstract: A system for forging a rack bar from a blank pipe. A blank pipe 1 is held between dies 2 and 3. Stockers 7L and 7R are arranged on respective sides of the die set. In the stockers 7L and 7R, left-handed shuttles 6L1, 6L2, 6L3, . . . 6Ln and right-handed shuttles 6R1, 6R2, 6R3 . . . 6Rn are stored. First, a left-handed presser rod 5L inserts the shuttles 6L1 to the blank pipe from the left-handed stocker 7L. Then, a right-handed presser rod 5R inserts the shuttles 6R1 to the blank pipe from the right-handed stocker 7R, causing the shuttles 6L1 to be entrained and returned to the left-handed stocker 7L. Vertical shift movement is alternately executed between the left-handed and right-handed stockers 7L and 7R, so that a shuttle of step-likely increased working height is selected for executing a working process.

Abstract: A system for forging a rack bar from a blank pipe. A blank pipe 1 is held between dies 2 and 3. Stockers 7L and 7R are arranged on respective sides of the die set. In the stockers 7L and 7R, left-handed shuttles 6L1, 6L2, 6L3, . . . 6Ln and right-handed shuttles 6R1, 6R2, 6R3 . . . 6Rn are stored. First, a left-handed presser rod 5L inserts the shuttles 6L1 to the blank pipe from the left-handed stocker 7L. Then, a right-handed presser rod 5R inserts the shuttles 6R1 to the blank pipe from the right-handed stocker 7R, causing the shuttles 6L1 to be entrained and returned to the left-handed stocker 7L. Vertical shift movement is alternately executed between the left-handed and right-handed stockers 7L and 7R, so that a shuttle of step-likely increased working height is selected for executing a working process.

Abstract: Method and apparatus for producing a thin walled tubular product with thickened flange. A first stage metalworking (drawing) of a circular plate material A is done by using a first die set 22 having a conical die 24 and a drawing punch 26 is done in a manner that the end of the blank plate is remained on the conical surface 24-1 of the die, so that a semi-finished tubular product A1 with a inclined flange A1-1 is obtained. Then, a second stage metalworking (drawing) of the semi-finished tubular product A1 is done by a second die set 32 having a shaping punch 34 and a restraint die 36. The semi-finished tubular product A1 is held by the restraint die 36 and the shaping punch 34 is introduced into the semi-finished tubular product A1 for effecting a wall thickness reduction under ironing principle while forming a stepped portion.

Abstract: A method for producing a rack bar for a steering mechanism in an automobile. A blank pipe is held in a die, which has, at its inner surface, linear tooted portions. Mandrels are inserted repeatedly to the blank pipe while the direction of the insertion is alternately changed, while the insertion of the mandrel on one side of the blank pipe and the withdrawal of the mandrel on the other side are overlapped. Furthermore, lubrication is controlled so that an increased temperature of the work around 200° C. as generated under the plastic deformation of the metal is kept. An increased efficiency as well as reduced cost are obtained.

Abstract: A method for producing a rack bar for a steering mechanism in an automobile. A blank pipe is held in a die, which has, at its inner surface, linear tooted portions. Mandrels are inserted repeatedly to the blank pipe while the direction of the insertion is alternately changed, while the insertion of the mandrel on one side of the blank pipe and the withdrawal of the mandrel on the other side are overlapped. Furthermore, lubrication is controlled so that an increased temperature of the work around 200° C. as generated under the plastic deformation of the metal is kept. An increased efficiency as well as reduced cost are obtained.

Abstract: A method of manufacturing a ball valve element includes a recess forming step in which a press die is used to form two stem recesses in an outer peripheral surface of pipe material cut to a prescribed size, the stem recesses being formed at positions that are symmetrical with respect to the center axis of the pipe material, and a ball-shaped element forming step in which the pipe material in which the stem recesses have been formed is placed in a split die having substantially spherical forming surfaces, with the openings in the pipe material facing the spherical forming surfaces of the split die, and pressure is exerted by the split die to uniformly and symmetrically deform the pipe material into a sphere.

Abstract: A boost valve device is described which comprises a valve body formed therein with three check valves and hydraulic circuit including the check valves, which circuit functions to recirculate oil discharged from one side of a cylinder during no load operation to the other side of the cylinder to thereby boost the operation velocity of the cylinder under no load operation and to return the discharge oil to an oil tank during load operation. The valve body has an upper surface provided with ports corresponding to ports of a directional control valve and a lower surface provided with ports corresponding to ports of a manifold and is sandwiched between the directional control valve and the manifold with the ports in alignment.

Abstract: In a press which comprises an upper frame provided at the forward end thereof with a main cylinder, a lower frame opposed to said upper frame across a vertical spacing and a shank frame attached integrally to the ends of said upper and lower frames so as to provide support therefor and which is adapted to produce pressure for required fabrication by hydraulically actuating said main cylinder, an auxiliary cylinder is incorporated parallel to the main cylinder of the upper frame between the main cylinder and the shank frame and the forward end of the piston of said auxiliary cylinder is fastened onto the lower frame by the medium of a tension bar. The hydraulic actuating fluid is delivered to the auxiliary cylinder through a flow path which branches off from the flow path of said hydraulic fluid to the main cylinder, and the direction in which said fluid is delivered to the auxiliary cylinder is opposite that in which the fluid flows to the main cylinder.

Abstract: In a press for forming a long and narrow plate or strip of metal or synthetic resin into an elongated beam having an L-shaped section, of the type having a lower fixed frame provided with a female die on the top thereof and a hydraulically operated upper movable frame provided with a male die on the bottom thereof, a long space adjacent and parallel to the lower surface of the movable frame is provided in the movable frame. In the space are provided a plurality of small hydraulic deflection cylinders with pressure-fluid paths connected to the pressure-fluid paths of the main hydraulic cylinders to drive the movable frame. The space provided with a plurality of the small hydraulic deflection cylinders is so located that the center portion of the lower part of the movable frame is deflected counter to the deflection of the movable frame under press-forming load.