| 摘要 |
PURPOSE:To ensure to prevent backlash, by providing projections with either one surface of opposing arm metals and device frame, providing pushing out piece giving the pushing out force transversally to the metal arm with another surface so that the pushing force can effectively be operated to a given direction. CONSTITUTION:In the device frame B, a push-button device fitting the push-button 11 to one end of the linking piece 12 is provided, and this is supported to the device frame B freely slidably. Further, another end of the linking piece 12 is engaged to the operating member 6, projections 17, 17' are provided to either one surface of the metal arm 1 and the device frame B, and the pushing piece 20 which gives the pushing force transversal to the arm 1 in operation with the projections 17, 17' when the metal arm 1 slides forward is horizontally fitted. Thus, the pressing force exerted between the pressing piece 20 and the projections 17, 17' is effectively operated to a given direction at all times, allowing to ensure to prevent the backlash. |
