Patent GB-191120335-A (GB)
Title: Improvements in Variable Speed Gearing.
Inventor: FELLOWS HUGH WILLIAM
IPC: F16H29/08
Filed: 1911-09-13
Granted: 1912-09-13
Abstract: 20,335. Fellows, H. W. Sept. 13. Variable-speed ratchet gearing. - Relates to variable-speed gearing of the kind in which the engine-shaft may drive a driven shaft either through a countershaft and an adjustablethrow ratchet gear, or alternatively at a single higher speed by means directly connecting it to the driven shaft, and comprises primarily means for adjusting the ratchet gear and for automatically operating a clutch when the maximum degree of oscillation is produced, so that the direct high speed gear is thrown in and the ratchet gear is thrown out of operation. Specification 15,313/09 is referred to. The shaft 2 to be driven is connected by a variable ratchet gear to a countershaft 3, and also by a bevelpinion 7 to a loosely-mounted pinion 5 on the driving-shaft 1. The countershaft is similarly connected by bevel-pinions 4, 6 to the driving- shaft 1. By means of a clutch 8, 11, the drive may be transmitted through the countershaft and the variable ratchet gear, while a direct drive at a higher speed may be effected through the pinions 5, 7 by means of a clutch 9, 12. The slidable clutch parts 11, 12 carry pivoted bell-cranks 13, the arms 15 of which bear against thrust pins 16 carried by a sleeve 17, which is held from end movement by a collar 18 secured to the shaft 1 by a taper pin 19. The bellcranks are tilted to force the clutch parts into engagement by means of a slidable sleeve 20, the parts being so proportioned that in shifting the sleeve 20 both clutches are momentarily in engagement at the same time to prevent any interruption in the drive. The variable ratchet gear between the countershaft 3 and the driven shaft 2 comprises three sets of pawl-carrying members on the shaft 2 oscillated by corresponding sets of adjustable linkages from cranks 21 on the shaft 3. V-grooved disks 37 on the shaft 2 are intermittently driven by pawls 41 carried by transverse spindles 39 mounted in oscillatory disks 24. The pawls are formed with convex wedging surfaces 44 and are secured to squared portions of the spindles 39 by means of plates 43, as shown in Fig. 6. At one end of the spindles 39, collets 47 formed with concavities 49 are secured and co-operate with spring- pressed plungers 48 carried by a shift ring 45 to hold the spindles 39 in such positions that the pawls 41 are in mid-position (disengaged) or tilted so as to drive in either direction. Each shift ring 45 is formed with a toothed segment 50 engaged by a gear 51 on a short shaft 52 mounted in a bearing carried by the adjacent oscillatory disk 24 and provided with a crank arm 53 riding in a groove 55 in a normally stationary member 56. The grooved members 56 are carried by a rod 57 slidable in bearings 58 on the main frame 30. By end movement of the rod 57, the shift rings 45 are moved relatively to the oscillatory disks 24 and rock the pawl spindles 39 for the purposes indicated above. The oscillatory driving-movements of the disks 24 are effected by the cranks 21 on the shaft 3 through links 22, 23, the links 23 being connected at 25 to radius levers 26 pivoted at 27 to an adjustable frame or bracket 28 which itself is pivoted at 29 to the main frame 30. The effective stroke of the link 23 is determined by the position of the fulcrum 27 of the constraining-lever 26, the minimum stroke position being indicated in Fig. 2. As the bracket 28 is rocked to the right, the stroke of the link 23 and the corresponding speed of the driven shaft 2 increase. The bracket 28 is connected by a link 31 to an operating-lever 36, by means of which its position may be adjusted. The lever 36 is also connected by a slotted link 34' and a pivoted lever 65 to a pivoted forked lever 62, 63, by means of which movement of the clutchoperating sleeve 20 is effected. The parts are so arranged that the sleeve 20. is automatically shifted to throw the direct drive into operation when the bracket 28 reaches the position in which the maximum stroke of the ratchet device is obtained. To prevent reversal of the pawl elements 41 except in the minimum stroke position of the ratchet driving device, movement of the shift rod 57 is normally prevented by a pivoted catch 59 which is released from a notch 61 in the rod by means of a suitable projection (not shown) on the frame 28 only when the latter has been moved to its lowest position.