| 摘要 |
PURPOSE:To prevent production of noises and friction, by holding the reciprocating rof of a pump near a position of its maximum stroke when the pressure produced by the pump is higher than a prescribed value, and thereby preventing impulsive contact between a rocker arm and the reciprocating rod. CONSTITUTION:When a reciprocating rod 8 comes to the position of its maximum stroke, a solenoid valve 25 is closed. At the position of the maximum stroke of the reciprocating rod 8, i.e., when the volume of chamber 14 is minimum, the suction side is closed by the solenoid valve 25, and a diaphragm 10 is attacted downward by the negative pressure in the chamber 14. Resultantly, the reciprocating rod 8 is held at the position of its maximum stroke, so that operation of a vacuum pump 7 is stopped and moreover the rod 8 does not come into contact with a rocker arm 4 that is moved by a cam 2. Therefore, it is enabled to prevent the production of mechanical noises and friction or the like due to impulsive contact of mechanical parts. |
