Closed tooling for hot pressing of watch cases - has hydraulic pressure increased as punch descends and released at preset safety value

摘要

The tooling comprises a top portion (1) containing a chamber (12) filled with hydraulic fluid and a piston (2). Its lower face is extended through a sealing plate (8). Guide rods (7, 10) align the top portion in the die (4). The rods also guide a mobile punch plate(9). Pressure is obtained by contacting the piston lower face. The hot slug (5) is placed in a die cavity (11) and a punch (3) descends to shape the part. The pressure increases the hydraulic pressure in the chamber and this is released (14) at a preset safety value to prevent tooling damage.