| 摘要 |
A mechanical transmission system for transferring rotational motion between shafts comprising juxtaposed drums mounted on said shafts and a cable mechanically linking the drums. Each end of the cable is attached to the surface of one of the drums, and the cable is wound partly around each drum and maintained under tension. Preferably, the surfaces of the drums are continuously grooved, and the cable follows in the grooves. The cable is mounted such that as the cable is wound onto one drum it is unwound from the other drum. The drums can be of varying diameter through their lengths to continuously vary the ratio of angular velocities. In a preferred embodiment, the mechanical transmission system is used in tensioning and transferring a flat web, such as magnetic recording tape, between two reels. Each of the reels is mechanically coupled to one of the drums, and the drums are frustoconical in shape and helically grooved. The drums are mounted inversely to each other such that the wide end of each drum is juxtaposed with the narrow end of the other, and the cable is attached near the wider end of each drum. The ratio of the radius of the narrow end of each drum to that of its wide end equals the ratio of the radius of its associated reel when empty to that of the reel when fully wound. The tape can be moved at constant speed by driving the cable at constant speed.
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