| 摘要 |
<p>A shutoff valve (36, 136) includes nozzle (28), adapted to be moved relative to a hot runner assembly (50), and operable to communicate with the hot runner assembly (50) when in a forward position. The nozzle (28) includes a melt channel (30) having a first narrow portion (70), a second narrow portion (72), and a wider portion (74) located therebetween. A ball (76) is located within the wider portion (74) of the melt channel (30), and adapted to close the shutoff valve (36, 136) when abutting against one of the first narrow portion (70) and the second narrow portion (72), and open the shutoff valve ( 136) when displaced away from the one of the first narrow portion (70) and the second narrow portion (72). An anvil (92, 192) is mounted to the molding assembly (50). The ball (76) is urged towards its closed position by melt pressure. Moving the nozzle (28) into the forward position causes the anvil (92, 192) to move the ball (76) from the closed position into its open position.</p> |
