| 摘要 |
PURPOSE:To improve safety, by providing a piston for controlling the amount of lift of a check valve in confrontation with a check valve for opening and closing a high pressure chamber in a tappet between a cam and a push rod for obtaining its maximum lift amount when the pressure of supplied operating fluid drops. CONSTITUTION:A tappet 4 comprising an inner cylinder 14 having a piston 16 therein and an outer cylinder 12 housing the inner cylinder is interposed between a cam 2 and a push rod 3. Lubricating oil enters into an upper chamber 20 from a passage 11 through pores 17, 19, into a lower chamber 22 through a pore 23, and further into a high pressure chamber 18 through a check value, respectively. When the cam 2 pushes upwardly, the oil in the high pressure chamber 18 is closed by a check valve 12 for thereby moving the push rod 3 upwardly. When the pressure of operating fluid supplied from the passage 11 drops, the inner cylinder 14 is moved upwardly by a spring 24 and the a sufficient amount of the oil is stored in the high pressure chamber 18. As a result, the maximum amount of lift is held at all times, whereby preventing the tappet from being out of oil.
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