| 摘要 |
<p>PURPOSE:To discharge air naturally without impeding pump performance by boring an air vent hole opened to the displacement chamber of an oil hydraulic pump used for the lifting cylinder of a driver's stand. CONSTITUTION:Bore holes 3f, 3g provided to extract the air in a displacement chamber 3d are connected to the periphery of a piston 3c through the piston lower end face 3e adjacent to the displacement chamber 3d. The portion of the bore hole 3g opened to this periphery is opened to the upper section of said piston 3c at its bottom dead point in contact with the inlet section 3h of a cylinder 3a. The air flowed into the displacement chamber 3d is naturally discharged through the bore holes 3f, 3g when the piston 3c is at its bottom dead point.</p> |
