| 摘要 |
<p>The pre-punching tool is for the production of seamless rings from rod cutoffs and eliminates the use of bottom dies for centering the blanks. The circular cutoffs are placed by a coordinate-controlled manipulator onto one of the three operation stages comprising upsetting, pre-punching and piercing. The two punches are coaxially oppositely fitted in respective holders on the table and ram. Each punch is provided with a yielding support plate, with a hole through which the punches project during operation. The axial movement of the plates takes place against the hydraulic pressure of pistons sliding in cylindrical bores fed with pressurised fluid-cum-coolant through the inlet.</p> |
