| 摘要 |
1286269 Variable ratio gearing A B SAVIDGE 30 Sept 1971 32559/69 Heading F2D [Also in Division G1] In a speed or ratio measuring and/or controlling device comprising a measuring disc 9, which engages a screw thread on a measuring shaft 10, is in rolling, frictional engagement with a rotatable member 7 and indicates speed or a ratio by its translation along its rotational axis, the pitch angle of the screw thread can be selected to assist transfer of rotational effort from the member 7 to the shaft 10 in a proportion suitable for a particular application of the device by constructing the disc 9, shaft 10 and appended parts in modular form, the interchangeable modules providing different screw thread pitch angles. An indicator provides readings proportional to the movement of the disc 9 from a reference position and may comprise a dial rotatable with respect to a fiduciary mark by a gear train operated by a rack translated by the disc 9 which may be provided with a tyre 12. Limit switches may be provided for remote indication or for retroactive control of the speed or ratio. The speed of any shaft that can frictionally drive a measuring wheel and thence the shaft 10 can be measured if the member 7 is positively driven at a known speed. Applications suggested include miles-pergallon indication when the member 7 may be vehicle driven and the energy transmitted through the disc 9 to the shaft 10 can be made to reinforce the fuel pump drive thereto by using a course pitch thread; yarn-to-machine production rate when the use of a fine pitch thread reduces the risk of breaking the fibre by transmitting too great a tension thereto. The disc 9 may be made of hardened steel. A conical tip 8 of member 7 may be made of urethane and a cone angle of 60 degrees provides a linear relationship of axial translation of disc 9 to diameter of cone section. |
