| 摘要 |
<p>PURPOSE:To facilitate the change-over between the transmission and isolation of torque of a gear mechanism with a small force, by providing a means for moving a primary gear in the direction parallel to the rotary shaft of the gear, and by forming projections on a part of teeth of a primary gear, which are projected laterally of the gear. CONSTITUTION:Projections 4a are formed on a gear 4 so that the gear 4 may be surely meshed with the associated gear 2a even by a small spring force when the gear 4 is depressed downward by the force of a spring 19 and therefore it meshes with the gear 2a. The projections 4a formed on the gear 4 are arranged at intervals such that the number of them is less than the number of meshing teeth of the drive gear 2a. With this arrangement, even if teeth of two gears are not yet meshed, the gear 2a always abuts against one of the projections 4a so that the gear 4 is initiated to rotate, and therefore normal meshing may be at once made.</p> |
