| 摘要 |
<p>This invention relates to an improved hydraulic actuator such as those used to reciprocate the valve pin in an injection molding system. A small diameter hole (18) is provided through the piston (13). This allows a limited flow of hydraulic fluid from one side of the cylinder (12) to the other, but yet enables the piston to control the valve pin or other mechanism in the manner necessary. This small flow of hydraulic fluid provides for the escape of trapped air, relieves stagnation and excessive temperature build up in the fluid, and avoids the accumulation of sediment and corrosion.</p> |
