SPECIAL HYDRAULIC PRESS FOR DEEP DRAWING OF HOLLOW PRODUCTS Russian patent published in 1995 - IPC

FIELD: metal pressure forming. SUBSTANCE: special hydraulic press for deep drawing of hollow products includes punches of first and second transitions, being in the form of hollow pistons of hydraulic cylinders of double-action type, and a punch of third transition, being in the form of movable hydraulic cylinder of double-action type with an outer diameter, equal to an inner diameter of a ready product. The third transition punch is inserted coaxially into the punch of second transition and forms an annular cavity together with a rod, rigidly joined with the second transition punch. Values of working stroke of the punches pistons of second and third transitions are restricted by a length of respective annular cavities of hydraulic cylinders in such a way, that between the first transition punch and a second transition die and also between the second transition punch and the third transition die a normalized gap is provided. A value of that gap is equal to a thickness of a bottom of a blank. The dies of second and third transitions are mounted in the holder with possibility of fine adjustment of their position along an axial of the press. EFFECT: accurate centering of tools of the press, providing enhanced quality of products, low dimensions of the press, simplified structure of the press and therefore lowered cost of the whole equipment. 3 cl, 1 dwg