Patent ID: 7004006

Claim:
A motor driven link press characterized by comprising a motor, a link mechanism that converts rotating operation transmitted by the motor via a drive transmitting system, into a linear operation, and a ram installed below said link mechanism to elevate and lower for press working on the basis of said linear operation, said link mechanism comprising a crank member having a crank shaft and an eccentric shaft portion, a pivoting link having a first to third connecting portions located at vertices of a triangle and which are used for rotatable connections, the first connecting portion being connected to the eccentric shaft portion of said crank member, a connecting rod having opposite ends connected to the second connecting portion and an upper end of said ram, respectively, and a restraining link having a proximal end rotationally movably connected to a frame and a leading end connected to the third connecting portion of said pivoting link, the restraining link restraining pivoting of said pivoting link so that a lowering operation of the ram is slower than an elevating operation of the ram when said crank shaft is rotated at a fixed speed in one direction, said drive transmitting system controlling rotation of the motor to transmit rotational driving effected by said motor to said crank shaft so that an elevating and lowering operations of the ram can be controlled, wherein said motor is a servomotor, and wherein said link press is a punch press, and that section of elevating and lowering stroke of said ram which is used to punch a plate material workpiece is an intermediate section of lowering process of said elevating and lowering stroke.