Patent GB-562170-A (GB)
Title: Bicycle locks
IPC: B62H5/06
Filed: 1942-08-07
Abstract: 562,170. Locking cycle steering-stems. SCHWINN, F.W. Aug. 7, 1942, No. 11099. Convention date, July 31, 1941. [Classes 79 (iii) and 136 (iii)] The handle-bar stem 30 and front fork extension 14 can be locked against rotation in the steering head 10 of a cycle by means of a slidable bolt 57 controlled by a lock 63 and key 69 and having three positions, in one of which it locks the stem 30 and fork 14 against rotation relatively to the steering head, in another it is partly retracted and allows the stem and fork to rotate in the head but prevents the stem from being withdrawn from the fork to allow access to the lock, and in the third position the bolt is completely retracted and allows the stem to be withdrawn from the fork either to allow the height of the handle-bars to be adjusted or to give access to the lock. In the construction shown, the handle-bar stem 30 is slidable in the fork extension 14 and is secured in position at different heights by means of a two-part ring 40, Fig. 10, which is adapted to be inserted in any one of a number of grooves 37 in the stem and is provided with tongues 41 which lie in longitudinal grooves 38 connecting the grooves 37. The ring 40 is gripped in place by a cap 45 screwed on to the upper end of the fork extension 14. A sleeve 48 is screwed on external threads of the cap 45 and clamps a plate 50 to the top of a bearing cone 28 of the upper ball bearing 29 for the fork in the steering head, the plate 50 carrying the upper ends of the fork braces 52. The handle-bar 33 is adjustably clamped at 34 to the head 32 of the stem 30. A cylinder lock 63 is mounted in the stem 30 and is provided with tumblers 64 sliding in the plug 65 which can rotate in the stem but is prevented from axial movement therein by a cross-pin 66 in the stem associated with a groove 67 in the plug. The tumblers are normally projected into grooves 71, Fig. 12, by springs 70, thus locking the plug 65 against rotation in the stem 30. When the key 69 is inserted in the lock the tumblers 64 are reciprocated by the profile of the key and their ends extend into and out of grooves 71, 71<1> until the key is fully home, the tumblers then being flush with the surface of the plug 65 as shown. The key can now rotate the plug 65, and an eccentric pin 68 on the lower end of the latter working in a transverse groove 59, Fig. 4, in the bolt 57 moves it outwardly from the normal position shown in Fig. 2. If the key and plug are turned 90 degrees, the bolt passes into a vertical slot 23 in a sleeve 22 fixed to the steering head, so that the fork and stem are locked to the steering head with the fork and front wheel in the straight-ahead positions. Other slots 24 and 25 are provided in the sleeve 22 so that the front wheel and fork can be locked at an angle of about 60 degrees either right or left of the straight-ahead position. The slots 23, 24, 25 permit the vertical adjustment of the stem 30 ; if this is not required, holes the size of the bolt 57 are provided. To allow the vertical adjustment of the stem, the key is inserted in the lock and is turned a few degrees counterclockwise to move the bolt slightly to the right from the position shown in Fig. 2 ; this retracts the bolt from a vertical slot 61 in the fork extension 14 until it is wholly within the contour of the plug 65, so that by removing the two-part ring 40 the stem 30 can be withdrawn from or adjusted in the extension 14.