| 摘要 |
PURPOSE:To improve responsibility of a cam when changed over according to an operating condition of an engine, said cam driving intake and exhaust valves open and closed, by joining and connecting a cam piece with a plunger which slides by the force of compressed air. CONSTITUTION:Under the state where a rocker arm 9 is rocked by the low speed revolution cam 5 of a cam piece 3 to open and close intake and exhaust valves, if changeover of said cam to high speed revolution cam 6 is needed due to increase in engine speed, a change-over valve not illustrated is changed over, whereby sending high pressure air into a pressure chamber 43 via a pipe 47. A plunger 29 is then forced to the right and the flange-like member 8 of a timing mechanism 10 is turned until the small diameter part thereof is engaged with a piston 22 so as to permit a retaining part 24 to be released from a retaining hole 25. The plunger 25 is then moved to the right. The timing mechanism 19 is engaged in the second retaining hole 26 and the cam 6 of the cam piece 3 which is moved to the right coincidently with the engagement may engage the rocker arm 9. |
