| 摘要 |
PURPOSE:To improve durability and obtain safety by attaching an intermediate lock clutch onto a projection formed on an arm having a receiving metal when the arm is at an intermediate position and locking the arm by attaching an upper limit lock clutch under pressure onto the stepped part of the arm when the arm is at the upper limit position. CONSTITUTION:A projection 57 for stopper is installed onto an arm 16 connected to a receiving metal board 17, and a stepped part 16f is formed on the undersurface of the base edge part of the arm 16. A rotary shaft 49 is installed rotatably onto a shaft 48 fixed onto the side plate 2 of a jack body 1, and an intermediate lock clutch 51 and an upper limit lock clutch 50 are installed onto the rotary shaft 49. Both clutches 50 and 51 are urged by a spring 52, and one clutch 51 contacts with the projection 57 when the arm 16 turns to an intermediate position. The other clutch 50 contacts with the stepped part 16f when the arm 16 is turned to the upper limit position, and the arm 16 is locked at each position. Therefore, the lock of the arm 16 is released by shifting a lock and unlock bar 53 leftward.
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