PURPOSE: To improve a forming accuracy and product yield by providing an offset cylinder between a punch and punch cylinder and providing an oil pressure control device controlling this offset cylinder.
CONSTITUTION: A billet 1 is interposed between forming dies 2, 3 and between a punch 7 and an anvil 8 and a press oil is fed from the upper port of an offset cylinder 24 simultaneously with descending a crosshead 15. A precompression stage is executed with a cylinder main body 24A being ascended, the punch 7 holding a step state and the billet 1 being compressed with cradles 13, 14 being moved to the opposed inner part by the descent of the crosshead 15. In succession, the press oil is fed from the lower port of the cylinder main body 24A by switching to an oil feeding pipe 30 by operating a solenoid valve 31, and the cylinder main body 24A is descended. The forming stage forming a pin part 6 and arm parts 9, 10 is performed with the punch 7 being descended.
SAKAMOTO SHIRO
ANDO YASUO
| JPS4924337A | 1974-03-04 |
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