| 摘要 |
PURPOSE:To decrease the length of an operation grip part and to reduce an operating turning stroke by providing a cam mechanism between the lower end part of an operation lever and a turning arm to lock the resetting turning to the neutral position with a contact with the tip part of the operation lever. CONSTITUTION:When an operation lever 2 is set at a neutral position (a), a stopper part 28 has a contact with a shaft 1 with turning cams 3 and 4. Then tension pulleys 17 and 18 are separated from a belt, and the tip part 5 of the lever 2 is held between cams 3 and 4 at the front and rear sides. Thus the part 5 is kept at a position (a). Then the lever 2 is turned to a low-speed position (b) and therefore a sloping edge 14 of the cam 3 is pushed outside by the part 5 and turned round a shaft 11. Thus the pulley 17 stretches a low-speed belt 26. In this case, the cam 3 is stretched toward 1 by a spring 22 and therefore a bridge function is produced between the cam 3 and the part 5. Thus the lever 2 is prevented from returning to the position (a). However the lever 2 can be reset to the position (a) with a forcible operation. The part 5 is reset to its original position after sliding the edge 14 against the tension of the spring 22. Then the lever 2 is set at a high-speed position (c), the pulley stretches a high-speed belt 27 in the same way as the pulley 18. |
