GB722363A - Change speed gear of the chain shifting type for bicycles and the like vehicles - Google Patents

Abstract

722,363. Chain shift change speed gearing. JUY, L. C. H. July 2, 1952 [Aug. 24,. 1951], No. 16670/52. Class 80 (2). Chain shift change speed gearing of the type described in Specification 622,249 for bicycles &c., comprises a carrier arm 6, Fig. 1, pivotally secured to a plate 1 on the bicycle &c., frame 2, its free end carrying a device controlling the to-and-fro movement of the chain 8, while a spring 11, Figs. 2, 5. exerts on the carrier arm an adjustable thrust urging it rearwardly with respect to the frame, the device controlling the to-and-fro movement being constituted by a sleeve 15, Fig. 3, screwed into the carrier arm and within which is slidable and revolvable a spindle 16, the outer end of which is secured to a chain tensioning arm 7 carrying at each of its ends a roller 9, 10. The spindle. 16 is connected with a control cable 19 and surrounded by a coil spring 17 under tension between the carrier and tensioning arms, a washer 24, Figs. 3, 6, being provided for angularly shifting the sleeve 15 independently of the drawing action of the cable 19 upon it, to permit transverse adjustment of the chain tensioning arm and the rollers in the plane of the sprockets selectively engaged by the chain. The washer 24 has two flat internal surfaces 24<SP>1</SP>, Fig. 6, engaging corresponding surfaces on the sleeve 15 so that, the sleeve having threaded engagement with the carrier arm 6, rotation of the washer turns the sleeve which moves axially with respect to the arm. The parts are locked together by a nut 20 through a hole in which passes a small chain 18 connected between the spindle 16 and cable 19. The spindle and slseve are surrounded by a protective spring guard 23 and the ends ot the spring .17 are attached to cup-shaped members 21, 25, a projection 17', Fig. 2, at the end of the spring engaging in one of a number of notches in the cup-member 21 to enable the tension of the spring to be adjusted. The other end of the spring 17 is connected to a cable 26 varying its tension concomitantly with change of speed, substantially as described in Specification 684,211, so that the tension in the slack part of driving chain 8 is constant and independent of the driving sprocket engaged. The means for adjusting the tension in the spring 11, coaxial with the pivot of the plate 1, consists of a cylindrical member 14, Fig. 5, having a diametral bore through which one end of the spring is passed, its other end 11', Fig. 2, resting against the arm 6, the cylindrical member 14 being rotated to adjust the tension and then locked in position by a screw 13 passing through the unthreaded bore of a spindle 1<SP>2</SP> threaded into the plate 1. A stop 31, Fig. 2, or the like, is provided on the arm 6 to prevent its rearward movement when changing a wheel &c. Specification 618,348 also is referred to.