| 摘要 |
889,127. Change-speed control. FABBRICA ITALIANA MAGNETI MARELLI S.p.A. May 6, 1958 [May 6, 1957; Nov. 30, 1957], No. 14442/58. Class 80 (2). [Also in Group XXIX] In a gear shift for vehicles &c., wherein manual rotational and axial movement of a lever-operated rod A respectively effects, through arms 1, 3, 2, axial (cross-shift) and rotational (gear establishment) movement of a rod B, the said gear establishment only is assisted by a floating-lever, follow-up, pneumatic servomotor, comprising valves 6, 7 receiving compressed-air at A.C. and feeding a double-acting operating cylinder 12. When the rod A is axially moved, in either direction, e.g. in the direction f1, with the crossshift position M3, M4 predetermined, the arm 3 is rotated about a hinge 5 initially held stationary by the resistance of the rod B, to open a valve 11 feeding the end D of an operating cylinder 12, which moves a piston 15 rotating the arm 2 and the rod B in the direction f3 to establish a gear M3. The resultant rotation of the hinge 5 tends to close the valve 11 therefore pilot movement of the arm 3 by the rod A must be maintained until establishment is completed. In the event of pneumatic failure manual gear establishment is possible. Joints G1, G2 permit the removal or installation of the servomotor as a unit in an existing gear-casing. As shown, the rod B is centred at the M3, M4 cross-shift position by a spring. In Fig. 2, not shown, means to prevent unintentional servo-action by movement influenced by the inertia of the control members and the support elasticity comprises a prismatic coupling between the rod A and the arm 1 allowing spring-opposed axial lost-motion only. The female element fast on the arm 1 has three circumferential notches for engagement by a locating detent. |
