Patent GB-447643-A (GB)
Title: Improvements in or relating to free wheel hubs with back pedalling brake
IPC: B62L5/02
Filed: 1935-07-20
Abstract: 447,643. Coaster hubs. LINDLAU, (nee DAHMEN), C., 16, Friesenplatz, Cologne, Germany. July 20, 1935, No. 20712. [Class 136 (ii)] In a free-wheel hub with back pedalling brake, the axially moving member which couples to the drive or to the brake-means according to the direction of pedalling, is formed in two parts, viz. a ring 18 which couples the chain wheel 10 to a ring 8 screwed on to the hub casing 2, and thereby effects the drive ; and a brake ring 23 which with the drive ring 18 is mounted upon a guide ring 17 revoluble and slidable on the ring 8. The ring 17 is grooved helically in two opposite hands to receive helical projections 20, 24 on the rings 18, 23 respectively, the projections being of opposite hands to correspond with the grooves in the ring 17. The ring 18 has peripheral helical teeth to engage helical grooves in the inner surface of the wheel 10, the hand of these teeth and grooves being opposite to that of the teeth 20. The rings 8 and 18 have teeth on their opposed faces through which the drive is effected when the rings 18, 23 move to the right. The ring 8 has tongues 15 which project through a cross-shaped opening in a split expandable conical brake disc 31 which is thereby entrained, the disc 31 being normally kept away from the conical braking surface on the cover 33 by a spring 37. When forward pedalling commences, the helical disposition of the grooves and projections on the chain wheel 10 and rings 18, 23, 17, moves the rings 18, 23 to the right and the teeth on the rings 8, 18 are thereby engaged. The movement to the right is ensured by the slight frictional drag of the ring 17 and the opposite hands of the grooves therein ensure that the rings 18, 23 will be pressed tightly against each other. When the drive connection is established, all the parts of the hub, except the shaft 1 and the cover 33 rotate together. When freewheeling, the rings 18, 23 move to the left and the ring 8 only rotates with the hub. When back pedalling commences, the rings 18, 23 move further to the left, the brake disc 31 being forced against the braking surface on the cover 33. Additional braking is obtained by the opposite side of the disc 31 engaging in a conical groove in the ring 23. The ring 23 is formed with teeth facing grooves 35 in the cover 33. A spring 28 embracing the ring 23 has an outturned nose which first engages a groove 35 and positions the ring 23 for registration of the teeth thereon with the grooves when the rings 18, 23, under further backpedalling effort, move further to the left. The ring 8 and the flange 3 of the hub casing have opposed projections 9 which are coupled. by a star-shaped member 5, with radiating arms, which is normally kept against the ring 8 by a spring 6. When the ring 8 is being screwed upon thread of the hub, the member 8 is pushed towards the flange 3, leaving the ring 8 free to rotate. When the member 8 is released, it moves towards the ring 8 which is thereby locked to the flange 3. If desired, the other end of the hub may be arranged, as shown, as a fixed wheel.