| 摘要 |
1,178,788. Ratchet mechanism. INTERNATIONAL STANDARD ELECTRIC CORP. 30 Oct., 1968 [3 Nov., 1967], No. 51489/68. Heading F2Q. In a stepping mechanism of the type comprising a rotatable star wheel 1 and a forkshaped pivoted pawl 3 having arms 7, 8 whose ends 9, 10 comprise pairs of surfaces 13, 11 and 15, 14, adapted to engage the flanks of teeth on the wheel, the surfaces 13, 15 each comprise between one fourth and three fourths of the surface of the tooth flank, and the surfaces 11, 14 are at least equal to one fourth of the surface of the tooth flank. Preferably the surfaces 13, 15 are each substantially equal to half the surface of the tooth flank. The pawl 3 is rocked about an axle 6 by an electromagnet 4 co-operating with an armature 5 and a return spring. Preferably the wheel 1 and pawl 3 are made of plastics material. |
