US Patent 7765848 Press working method and press working apparatus

In a press working apparatus 10, while a servo motor 24 is acting, an upper die 38 is made to come close to a lower die 52 and press working of the first time is conducted on a steel plate 12. A slider 32 is raised to a movable punch preparation position. A movable punch 90 is protruded from a die face 38a of the upper die 38 by width H and locked by a mechanical lock 94. The upper die 38 is made to come close to the lower die 52 again and the steel plate 12 is pushed with the upper die 38 and at the same time an additional worked portion 12a is pushed and deformed with the movable punch 90 so as to conduct press working of the second time. After the movable punch 90 has been retracted, the slider 32 is raised.