| 摘要 |
<p>1,261,955. Brush holders for dynamo-electric machines. INTERNATIONAL BUSINESS MACHINES CORP. 7 Nov., 1969 [18 Nov., 1968], No. 54612/69. Heading H2A. The current collecting brush 36 in a rotary electrical machine is pivotally coupled to a leaf spring 44 which biases the brush towards the cylindrical current-collecting surface 26. In Fig. 4 the silver graphite brush 36 is coupled to leaf spring 44 by a ball-and-socket joint comprising a steel ball-bearing 40 glued into a cavity 42 in the brush and a concave depression 46 in the spring 44. Disengagement of the ball from the socket is prevented by a member 48 which has a portion 50 formed with flanges 52 (Fig. 3, not shown) crimped to the brush and a portion 56 which restricts relative movement of the brush and the leaf spring by engaging the depression 46. Further projections 60, 64 of the member 48 limit the relative movement in other directions. In another embodiment (Fig. 5, not shown) a hemispherical projection on the leaf spring constitutes the "ball" and engages a corresponding depression in the brush. The ball- and-socket joint is disposed at the centre of the brush if the electrical machine rotor is adapted for bidirectional rotation, and nearer the trailing edge of the brush if the rotor rotates in one direction only. The leaf spring 44 is secured at its fixed end in a moulded phenolic body (68). Current is conducted to the brush via the leaf spring and a flexible braided conductor (66) interconnecting the leaf spring and member 48. The brush is shown in use in a motor, Fig. 1, having a low-inertia rotor 16 comprising a thinwalled tube of epoxy filled glass fibre with printed conductors on both its inner and outer surfaces, a portion 26 of these conductors constituting the commutator. The stator comprises permanent magnets 18, with poles 20, supported by a collar 22 mounted on frame 12. The rotor includes an extension 16a supporting a capstan 34 which drives a flexible web, e.g. a magnetic tape or a belt, the whole rotating assembly being mounted on bearings on a fixed shaft 28.</p> |
