| 摘要 |
<p>1378850 Free-wheel back-pedalling brake hubs RALEIGH INDUSTRIES Ltd 22 Dec 1971 [8 Dec 1970] 58153/70 Heading B7E A back-pedal brake hub comprises a shell 10 mounted on ball-races 20, 22 for rotation about a spindle 12, a sprocket and driver assembly 14 at one end of the shell, the driver 40 having screw-threads engaging corresponding threads on a clutch member 18 such that forward movement of the pedals moves member 18 to the right to interengage teeth 46, 48 and drive the shell without applying axial load thereto. The teeth are each formed with a radially extending side and the other side disposed at an acute angle thereto, the radial sides interengaging to effect the drive. Back-pedalling moves the member 18 to disengage the teeth and apply braking force to the shell, again without applying axial load thereto. The braking force is applied by a brake assembly which may comprise interdigitated discs and pads as shown in Fig. 1, or may be formed as a radially expansible shoe 58, Fig. 5, expanded between a conical surface fixed relatively to the spindle, and a conical surface 62 on the clutch member 18. A drag spring is provided to urge the drive to disengage during free-wheeling.</p> |
