| 摘要 |
1,265,449. Ratchet mechanisms. SIEMENS A.G. 22 June, 1970 [21 June, 1969], No. 30280/70. Heading F2Q. Intermittent stepped rotation of a rotor 3 is effected by pawls 5, 6 carried by a reciprocating driving member 9 in accordance with the relative angular position of a control rotor 2 located between the pawls 5, 6 and the rotor 3. The rotor 3 carries a continuous outer row of teeth 4, adapted to be engaged by pawl 6, and an interrupted inner row of teeth, adapted to be engaged by pawl 5. The control rotor 2 has a row of teeth 1 adapted to be engaged by both pawls 5, 6, a hole 10 through which both pawls 5, 6 are adapted to pass and holes 11, 12 through which only pawl 5 may pass. Thus the rotor 3 is driven only when pawl 5 passes through aperture 10, 11 or 12 to engage one of the teeth in the interrupted row, or when pawl 6 passes through aperture 10 to engage one of the teeth in the outer row 4. In a modification, a control rotor 2 carries pawls 13 ... 16, Figs. 3 and 6, which are adapted to engage teeth on a rotor 3 under the influence of cams 18 provided on a fixed member 17. The pawls 13 are hammer-shaped, made of resilient plastics material, and moulded on to the rotor 2. They are spring-loaded on both sides. In a modification, each pawl 19 is formed by stamping and is mounted on a pin 20, Fig. 8, the necessary biasing being effected by gravity. |
