| 摘要 |
<p>329,433. Della Riccia, A. March 16, 1929. Controllers, actuating; controlling motors by varying terminal voltage. -The controller is automatically operated, one notch at a time, by a reversible electromagnetic ratchet-andpawl arranged to receive current through a polarized relay responsive to the difference between two voltages, one depending on the actual speed of the vehicle and the other depending on the calculated mean speed corresponding to the actual notch at which the controller is standing. In the arrangement shown in Fig. 3<a>, a small generator E, driven by the vehicle is connected to oppose its voltage to that of a stepped potentiometer R2 which gives a voltage depending on the position of a contact K moving in correspondence with the notches of the controller (not shown). The resultant voltage energizes a polarized relay W to close contacts a or r when the difference reaches a given positive or negative value, and thus directs current from the same or another source to a torque-motor F which operates the ratchet. The effect is that the controller is notched up or notched back according as the actual speed is less than or greater than the calculated mean speed at the particular notch, during starting, accelerating, or braking; In a modified arrangement, the stepped voltages are derived from a small motor-generator having its field varied in steps corresponding to the controller notches. The ratchet-and-pawl mechanism may take the form shown in Fig. 5a, where a pivoted lever L, operated by the torque-motor of Fig. 3a, has a lost-motion connection to a lever M carrying the pawl A, and is also joined to the pawl by a link T; the effect being that a downward swing of the lever L brings the pawl on the ratchet teeth before the lost motion is taken up, and that the continued movement then moves the lever M and the pawl with it through one tooth. A selfinterrupter S ensures a sharp return of the mechanism.</p> |
