Abstract: A press for manufacturing helical gears having a punch with a cutting edge; a die with a cutting edge, one of the cutting edges being shaped as a helical gear and the other having a shape corresponding to the shape of the one cutting edge; and a bolster rotatable about an axis and provided with one of the die and the punch. The die and said punch are pressed together and the bolster is rotatably driven by a driving element in response to a lead of a helical gear to be manufactured. The stroke of the punch is detected and a desired rotation angle of a driving element is calculated and then signalled to the driving element.

Abstract: An inverting machine for inverting metal molds 180.degree. including a bed, a stationary table on the bed, a pair of portal uprights standing on the table's lateral sides, a pair of slide frames slidably movable along the uprights, an inverting table provided between the slide frames and having a fixed securing element for holding a metal mold to be inverted, the inverting table being arranged in opposition to the stationary table, and a central shaft being pivotally supported by the slide frames and extending from a center of the width of each side of the inverting table. The ends of the central shaft are pivoted to rotate the inverting table about the central shaft. The slide frames are moved vertically relatively to the uprights. Pivoting and vertical moving may be done concurrently.

Abstract: A punch is pressed on a blankpiece into a die. The die is filled with liquid therein, whereby hydraulic counterpressure is generated by said pressing. The pressed blankpiece is forcibly followed in shape around the punch by hydraulic counterpressure, while part of the hydraulic counterpressure is automatically supplied to an outer circumference of the blankpiece via bypath passage. In case, the blankpiece is a plate, said supplied hydraulic pressure serves as compression force from the outer circumference of the flange to the radius direction. In case, the blankpiece is a product formed by a first drawing, said pressure serves as pressing force toward axial direction of a side wall of the product. When the supplied hydraulic pressure flows out from a space between the punch and a blank holder, the liquid serves as lubrication on an upper and lower surfaces of the blankpiece.