Abstract: A slide drive device for a press changes a slide stroke without a changing either a top or bottom dead center position of a slide. The slide drive device allows stroke adjustment without a loss of left-right balance in the slide drive device. An adjusting mechanism is driven by an eccentric part and a crank shaft. The adjusting mechanism is adaptable to fix either the top or bottom dead center position. A linear guide mechanism, is driven by the adjusting mechanism, and transfers adjustments in slope angle into changes in stroke relative to either the top or bottom dead center position without requiring a change in the dead center position. Alternate embodiments allow positioning and adjustment for convenience and economy.

Abstract: A slide-type pressing machine has a stroke length adjustment mechanism in which: changing of the stroke length does not effect the bottom dead center position of the press, adjustment is simplified, and the press is suitable for high speed pressing operations. The slide-type pressing machine has an eccentric section of a crank shaft which causes a slider to move up and down. An arm extends past a fixed pivot of an upper toggle link. One end of the arm is connected to the slider by a connecting link. A drive link and a drive connecting link are connected by a connecting pivot. A worm wheel is disposed on a frame, and is concentric with the connecting pivot when the slide is at bottom dead center. The worm wheel is arranged so that its rotation angle can be adjusted. A second arm is disposed in a radial direction from the axis of the worm wheel. A second pin is located at an end of the second arm. The second pin is connected to the connecting pivot via a third link.

Abstract: A slide drive device for a press drives a slide without employing a horizontal slide guide mechanism. Connecting rods move in a linear-type motion level with a balanced crank shaft to minimize vibration. A dynamic balance mechanism further reduces vibration and a slide height adjustment mechanism enables simple top and bottom dead center slide adjustment from a central location. The connecting rods transmit force from the crank shaft to upper links, and through middle and lower links to the slide. A fixed fulcrum pin on the upper link is vertically aligned with a slider pin on the middle link. A center fulcrum pin connects the upper and middle links at a fixed relationship. The slide drive device provides a lower slide speed for increased force adjacent the bottom dead center position and higher slide speed adjacent the top dead center position for speedier return.

Abstract: A slide drive device for a press changes a slide stroke without a changing either a top or bottom dead center position of a slide. The slide drive device allows stroke adjustment without a loss of left-right balance in the slide drive device. An adjusting mechanism is driven by an eccentric part and a crank shaft. The adjusting mechanism is adaptable to fix either the top or bottom dead center position. A linear guide mechanism, is driven by the adjusting mechanism, and transfers adjustments in slope angle into changes in stroke relative to either the top or bottom dead center position without requiring a change in the dead center position. Alternate embodiments allow positioning and adjustment for convenience and economy.

Abstract: A link mechanism for driving a slide in a machine press has a pivot pin with an adjustable position for varying the die height and the stroke length of the slide. A first link of the link mechanism is connected to a sliding member which is restricted to vertical movement in a groove. Another end of the first link is pivotally connected to a second link and a third link. Another end of the second link is pivotally connected to the pivot pin. Another end of the third link is connected to a plunger which is connected to the slide. The plunger is movably held in the machine press and restricted to vertical movement. The up and down motion of the sliding member is translated through the first link, second link, and third link into the up and down movement of the plunger and the slide.

Abstract: A transfer press provided with a three-dimensional transfer system and a moving bolster. In the press, there are provided one each of four corners of the bolster an advancing/returning unit for performing an advancing/returning operation on a workpiece, a clamping/unclamping unit for performing a clamping/unclamping operation on the workpiece and a lifting/lowering unit for performing a lifting/lowering operation on the workpiece. The units include motors that make it possible for the bolster to carry a pair of feed bars thereon and permit the units to perform their operations even when the bolster is outside the press.

Abstract: An apparatus for operating feed bars to move a workpiece between stages of a pressing machine includes cylinder devices. Each of the cylinder devices serves to move the feed bars linearly and each has a respective absolute encoder. The cylinder devices include a feed cylinder device which is responsive to hydraulic pressure to linearly advance and return the feed bars. First and second clamp cylinder devices are responsive to hydraulic pressure to move the feed bars linearly so as to clamp and unclamp the workpiece between the feed bars A hydraulic pressure supply circuit is connected commonly to each of the cylinder devices. Hydraulic pressure is applied to the cylinder devices through respective servo valves of a hydraulic valve arrangement.

Abstract: A crankshaft mechanism for use with a press having a slide member, which includes an eccentric crankshaft. In one form of the mechanism, the crankshaft has a cylindrical eccentric portion. An eccentric sheave is rotatably mounted on the circumference of the eccentric portion so that its center is displaced radially from the center of the eccentric portion. A connecting member is rotatably mounted on the circumference of the sheave. The eccentric portion, sheave, and connecting member have pin-receiving bores whose axes intersect the crankshaft axis. The bores in the crankshaft and connecting rod are both aligned with the sheave bores when the crankshaft and the sheave are in predetermined angular positions. Lock pins in the eccentric portion bore are selectively engageable with the sheave bores to fix the sheave to the eccentric portion. Lock pins in the connecting rod bore are selectively engageable with the sheave bores to fix the sheave to the connecting member.

Abstract: An apparatus for use with a press which corrects the spacing between an upper die and a lower die when the press is at bottom dead center. The apparatus includes a detector which is operative during each cycle of reciprocal movement of the press slide to detect the spacing between the upper and lower dies, a comparator which compares the detected spacing during each cycle with a prior spacing, an axially expansible/contractible piezoelectric actuator mounted on the press so that its axial length affects the spacing between the upper and lower dies when the press is at bottom dead center, and a drive circuit which is responsive to a deviation signal from the comparator to drive the actuator with a high voltage so as to expand or contract its axial length according to the difference between the detected and prior spacing of the dies.

Abstract: A Slide driving apparatus of press machine, wherein a main gear 3 as a rotational drive member and a lever member 10 as a driven member are opposed to one another in a eccentric state which an axes O.sub.1 and O.sub.2 are separated, the main gear 3 and the lever member 10 being connected to one another by a connecting member 13 consisting of a pin member 11 and a bush member 12. A drive rotation locus A which can be traced, round the axis O.sub.1, by a movement of a connecting center O.sub.5 where the main gear 3 and the connecting member 13 are connected, and a driven rotation locus B which can be traced, round the axis O.sub.2, by a movement of a connecting center O.sub.4 where the lever member 10 and the connecting member 13 are connected, intersect one another at points of C and D. A slide of the press machine is connected, by the connecting rod, to an eccentric portion 8A of the crankshaft 8 where the lever member 10 is fixed.

Abstract: A mechanism for guiding a slide of a press machine is disclosed. The slide is connected to a crank shaft extending laterally through connecting rods. The press further includes a bolster supporting a bottom die and a top die attached to the slide. An upper guide arrangement is provided between the slide and columns extending upward from a press machine bed for maintaining the slide parallel to the bolster by guiding a vertical stroke of the slide via contact at laterally spaced positions on front and rear sides of the slide. A lower guide is provided for horizontally adjusting the horizontal position of at least one of a first vertical structure including the slide and the press machine bed or of a second vertical structure including the top die and the bottom die to accurately set the dies.

Abstract: A double acting hydraulic cylinder is a die cushion for a press, with an upper and a lower chamber in communication with each other and with a differential pressure between the two chambers automatically controlled by a valve mechanism. With the differential pressure controlled according to one of several desired curves, the die cushion capability during press operation can be changed and adjusted to a valve suitable for the product to be processed and so a wide variety of products can be produced in high quality and high efficiency.

Abstract: A crank driving device for a press designed in serial type eccentric structure. An eccentric element of crankshaft connected to a connecting rod, and an eccentric mechanism to provide a second eccentricity, are separated in the axial direction of the crankshaft. The opposite ends of crankshaft are provided, in respective eccentric holes in a pair of rotatable bodies which rotate synchronously on a basic axial line. The crankshaft is axially displaceable between a position in which it rotates in synchronism with the rotatable bodies and a position in which the crankshaft and the pair of rotatable bodies can be rotated relative to each other. The eccentricity of the device is adjusted by rotating crankshaft and pair of rotatable bodies, relative to each other, and then maintaining the relative angle of the crankshaft and the pair of rotatable bodies at constant value by connecting means after adjustment.

Abstract: A closed type cylinder unit, instead of the open-to-atmosphere type cylinder unit of conventional equipment forms part of the die cushion apparatus. Based on the principle that the die cushion capability by the closed type cylinder unit is determined by the differential pressure between the lower chamber pressure and the upper chamber pressure, the differential pressure is controlled in such manner that the lower chamber and the upper chamber communicate with each other through a check valve, which is opened when the differential pressure exceeds a preset differential pressure value. As the upper and lower chambers communicate through a shut-off valve, which hinders the excessive increase of the upper chamber pressure when the piston goes up. Further, the form of the check valve is changed for conveniently changing and adjusting the die cushion apparatus during press fabrication.

Abstract: A dynamic balancing device for a press having a crankshaft, a connecting rod mounted on an eccentric portion of the crankshaft and connected to a slide at its free end. The balancing device has links mounted on the eccentric portion of the crankshaft and extending in the direction opposite the direction in which the connecting rod extends, a pair of balancing weights provided on opposite sides of the crankshaft and vertically movable; and a pair of levers having their one ends pivotally attached to the upper ends of corresponding balancing weights and having the other ends of corresponding balancing weights and having the other ends overlapped and pivotally connected with the links, the levers being pivoted on the press at their respective mid-portions.

Abstract: A dynamic balancing device for a press is provided for balancing the inertia forces generated by the reciprocating parts of the press using balancing weights. A connecting rod is mounted around the crank of the drive shaft and has one end pivotally connected to the slide and the other end pivotally connected to a link. The link is connected to a pair of levers extending in opposite directions. The levers are used to move a respective pair of balancing weights 17 in opposite directions to the direction of movement of the reciprocating members of the press. The balancing weights are guided by guide pins 18 received in bores extending through the balancing weights.

Abstract: In a transfer press having feed bars and a press drive, an improved feed bar driving apparatus has a vertical rod reciprocally movable in association with the press drive and having a threaded portion, a drive means to the vertical rod means for rotating the vertical rod means in opposite directions, a feed screw device connected to the threaded portion of the vertical rod for being rotated by the vertical rod in opposite directions by rotation and reciprocation of the vertical rod, a pair of feed bar receptacles slidably supporting the feed bars and connected to the feed screw device for being moved toward and away from each other when the feed screw device is rotated in respective opposite directions for moving the feed bars in a clamping and unclamping movement, a cam rotatable in assocation with the press drive, a lever mounted on a fulcrum and connected to the vertical rod and in contact with the cam for being pivoted around the fulcrum by the cam for moving the vertical rod through a stroke, and a strok

Abstract: A balancing device for a press of the type in which a slide moves up and down with respect to a bolster, the balancing device having an upward urging device mounted on the press and engageable with the slide to urge the slide upwardly when the die height clearance is adjusted and to be disengageable from the slide when the slide is moving up and down during operation of the press.