Shock absorber to reduce sudden jolts when starting and stopping a two color injection machine changeover mechanism has a valve slide actuated by roller contact with ramps on a cam rail fixed to an operating cylinder

摘要

A control valve(13) mounted on one cylinder(324) of a pair, which operate racks(321,322) of the changeover mechanism, has a valve slide(132) held in its fully open position by a spring. A control valve(13) mounted on one cylinder(324) of a pair, which operate racks(321,322) of the changeover mechanism, has a valve slide(132) held in its fully open position by a spring. A cam rail(14) parallel to the cylinders is fixed to a part moved by a second cylinder and has rising ramps(12) at both ends. A small gap exists between a guide roller(131) of the valve slide and cam rail when a working cylinder is fully loaded. On stopping and starting of the changeover system the roller contacts one ramp and the valve slide is pressed into the valve housing against the spring to open the valve. Each ramp(11,12) has either a flat, an upward concave or an upward convex inclined face. The cam rail(14) is fixed onto the rear end of a piston rod operating a rack(321,322) or is mounted on one of the racks.