Patent GB-649712-A (GB)
Title: Toric-disc variable speed friction gear
IPC: F16H15/38
Filed: 1947-04-21
Abstract: 649,712. Variable-speed friction gear. PICANOL, J. April 21, 1947, No. 10533. Convention date, Nov. 16, 1946. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 21, 1947.] [Class 80(ii)] A precessional shift, effective for one only, or for both directions of rotation for a pair of mutually contacting friction rollers 3, 4 transmitting drive i r series between opposed driving and driven tori( discs 1, 2, comprises a roller-mounting so arranged that initial movement oj the shift-lever, e.g. 24, Fig. 6, produces in the mount ing a turning component about a central transverse axis NO through the common roller-contact point m which offsets the disc. roller contact points laterally in opposite directions resulting in a precessional shift which spirals the rollersradially in opposite directions over the disc faces to establish a new speed-ratio. The rollers 3 4 are mounted on rigidly connected spindles 5, 6 which, in the reversible form shown in Figs. 6 and 7, are secured to a shaft i having cranked ends 17 engaging slotted cranks 19 turning in fixed bearings 25 and secured to a U-shaped member 23, which carries the shift-lever 24. The axis of the cranks 17 passes through the common roller-contact point m, and initial turning movement of the slotted cranks 19 by the shift lever 24 rocks the crankshaft 7, turning the roller-mounting about the radial axis NO, producing the precessional offset, and shift in either direction continues until the shift-lever 24 is returned to the central position which may be effected automatically when the required ratio position is reached. In Figs. 1-4 (not shown), the crankshaft 7 is inclined instead of the U-member 23, in which case the control acts for only one direction of rotation, and the roller-offset is gradually automatically reduced to zero when the rollers precess to a new ratio-position cor responding to the set position of the shiftlever 24. The latter is then subject to torque-reaction which may be resiliently opposed to provide a torque-responsive automatic shift-control. The reversible embodiment shown in Figs. 8 and 9 uses a floating-lever follow-up to cancel the roller-offset for terminating precession when the ratio-position corresponding to the set position of the shift-lever is reached. Three contacting pairs of rollers are used and their spindle-pairs bear in housings 29, 30, 31, the ball-shaped adjacent ends 33, 34; 35, 36 and 37, 32 of which are socketed in pairs in members 38 carried in bearings in the fixed casing, one member 38 having an actuating crank 46, turning movement of which rocks two, 29, 31, of the rollerhousings about the transverse axis (e.g. NO in Fig. 6), for precessional shift, this movement being communicated equally to the third roller-housing 30 due to the provision of a common torque-anchored central sleeve 42 having radial sockets engaged by projections 41 on all the roller-housings. The precession-crank 46 is operated by turning a handle 61 or 62 to a set position corresponding to the ratio required, thereby turning a shaft 71, a worm on which rocks a segmentally-toothed lever 57, which, in addition to turning a scale 70 through teeth 60 to indicate the ratio-setting of the handle, displaces a pivot, the upper end 56 of which engages a block slidable transversely in a slot in the lever 57 whilst its lower end 55 engages a block 54 slidable transverstly in a groove in a floating-lever 52 which is pivoted at 51 to a longitudinally-guided slide 48, engaging the pin of the precession-crank 46. The outer end of the floating-lever 52 pivots on a projection 53 carried by one, 29, of the roller-housings, which, as shown in Fig. 12; produces a follow-up action whereby, after the control handle 61 or 62 has initiated precession by moving the pivot 55 to a position 55a, thus swinging the floating-lever about the initially stationary pivot 53 to move the precession-crank shift-pivot 51 to an operative position 51a, the consequent precessional roller-shift causes the roller-frame pivot 53 to move to a new setting position 53a thus swinging the floating-lever back about the now stationary pivot 55a to restore the precession-crank shift-pivot 51a to the idle position 52, whereupon precession ceases with the rollers in a new ratio position corresponding to the setting of the controlhandle. The Fig. 12 action is effective for only one direction of rotation and to provide similar action for both directions, the pivot point 55 of the floating-lever 52 is automatically moved to the opposite side of the pivot 51, as shown in Fig. 13, when rotation reverses. For. this purpose the pivots 55, 56 pass through an additional block 64, Fig. 8, sliding in a slotted changeover lever 65, which is turned to one end position or another, according to the direction of rotation, by a pin-wheel 68, slowly and constantly rotated by the driving shaft and engaging a spring-loaded pawl 67 on the change-over lever 65. The block 64 carrying the pivots 56, 55, thus slides the latter in the transverse slots of the levers 57, 52 to position the pivot 55 in the Fig.. 12 or 13 position as required by the direction of rotation. The gear is driven by a motor or multi-groove pulley and has a lubricating oil-pump. The Specification as open to inspection under Sect. 91 refers to Specification 649,711. This subject-matter does not appear in the Specification as accepted.