Patent ID: 6260400
Filing Date: 2001-07-17
Classification: B21J

Abstract:
A fully enclosed forging apparatus comprising:a construction in which an upper die holder and a lower die holder are respectively disposed so as to face each other in a press machine, the upper die holder being composed of an upper holder main body holding an upper die and an upper holder base attached to the press machine, the lower die holder being composed of a lower holder main body holding a lower die and a lower holder base attached to the press machine, the upper and lower holder main bodies respectively attached to the upper and lower holder bases through plural spring mechanisms with an aperture as an interference of the spring mechanisms such that an upper punch proceeds into the upper die and a lower punch proceeds into the lower die after the upper die held by the upper die holder and the lower die held by the lower die holder contact; anda punch uniform movement mechanism, which closes a lower end of the upper punch and an upper end of the lower punch to approach a mating face position of the upper and lower die, with an approach speed of the upper punch toward the mating face position being equal to an approach speed of the lower punch toward the mating face position,the punch uniform movement mechanism comprising a cam disposed in a vacant chamber formed in the holder main body of the lower die holder, a cam holding member, which allows free rotation of the cam, the lower end of which is attached to the lower holder base of the lower die holder and the upper end of which is inserted into the vacant chamber, a sliding member fixed in the vacant chamber so as to contact a first sliding portion of the cam, and a push rod, the upper end of which is attached to the upper holder base of the upper die holder and the lower end of which is inserted into the vacant chamber through the holder main body and touching a second sliding portion of the cam, anda ratio of, a distance from a rotational center position of the cam to a first contact position of the first sliding portion and the sliding member, to, a distance from the rotational center position of the cam to a second contact position of the second sliding portion and the push rod, being set to be 1:2.