| 摘要 |
PURPOSE:To obtain the captioned apparatus in thin and simple form by installing a lever which has the engagement parts consisting of the engagement surface with the first gear and the engagement surface forming an acute angle with said engagement surface, at two positions, and in which the engagement surface is shifted for the pitch of the first gear at nearly equal intervals from the center of turning. CONSTITUTION:The angles theta1 and theta2 which the tooth tip part 1a and the dedendum part 1b of the first gear 1 form with respect to the center of the gear and the angles theta3 and theta4 which the engagement surface 2a of a lever 2 and the pitch between two engagement surfaces 2a form with respect to the center of the first gear 1 are set as follows: theta4 (2n+1)(theta1+theta3). A lever shaft 5 is arranged nearly at equal distance from two engagement surfaces 2b and 2c of the lever 2, and said both engagement surfaces 2b and 2c are arranged, shifted for the pitch of the first gear 1. Therefore, when the reverse transmission revolution is transmitted to the first gear 1, the engagement surface 1c of the first gear 1 is engaged with the engagement surfaces 2b and 2c of the lever 2, and the reverse transmission revolution of the first gear 1 is prevented.
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