| 摘要 |
This invention relates to mechanical double acting mechanism for actuating valve pins in a valve gated injection molding system. A number of valve gate units are aligned with a pneumatically driven toothed rack member. The rack member engages a hollow rotatable pinion member which is secured in each unit against transverse movement. The driven end of the valve pin is fixed in a bushing which extends through the pinion member and threadably engages it. The valve pin is actuated between the open and closed positions by longitudinally driving the rack member which rotates the pinion member and the bushing. In addition to providing a reliable and relatively inexpensive actuating mechanism, provision is made for relative axial adjustment of the valve pins prior to the commencement of operation which provides accurate valve seating without unduly high manufacturing tolerances. |
