Patent GB-522323-A (GB)
Title: Improvements in variable speed and motion transmitting mechanism
IPC: F16H29/00
Filed: 1939-01-03
Abstract: 522,323. Variable-speed gearing. BARBER, F. Jan. 3, 1939, No. 193. [Class 80 (ii)] In power transmission mechanism controlled at will or automatically and operable in reverse at a speed ratio variable from zero to a maximum, most of the motion of the driving shaft is imparted as rotation to the driven shaft and the mechanism is operated by the intermediate translation of a small part only of the rotary motion of the driving shaft into uniform straight line motion of radially-oscillating members carried by a rotatable frame, intermittent clutches transmitting the linear and angular motions of the members. Coaxial driving and driven shafts A, B are connected together through eccentric 2<1> on the shaft A, which forms a bearing for a pinion 2 connected by arms k and cranked coupling links K to the shaft B to rotate therewith, the pinion 2 meshing with an internally toothed ring 3 carried by a frame X rotatably mounted on the shafts A, B. The frame X is thus rotated by the shaft A at a speed dependent upon the relative speeds of the shafts A, B. A second frame D is rotated about the shaft B by a " reduction mechanism comprising a stationary eccentric 12<1> forming a bearing for a toothed ring 12 which rotates with the shaft B and meshes with an internally toothed ring 13 on the frame D. At its opposite side, the frame D carries a tubular extension D<1> concentric with the shaft B and supporting a pinion P located in the framing X. Power received by the frame X is transmitted to a sleeve shaft C, rotatable on the tubular extension. D<1>, through pivoted links p, q of which the links q are pivoted to arms 4 on the sleeve C. The links p are connected by cranks to small pinions Q engaging the pinion P and the opening and closing of the toggle formed by the links p, q imparts a non-uniform motion to the sleeve C. An eccentric ring E disposed around the sleeve C is pivotally mounted through a rigid arm on the end of an arm 5 secured tangentially to the sleeve C and its position is determined by a link 33 connected to an arm forming part of a speed-control mechanism. This mechanism comprises twin gear trains 30, 40, 50 and 31, 41, 51, the outside gears in a train being of equal size but the gear 30 which is secured to the sleeve C being smaller than the gear 31 which is rotatable on the sleeve. The axis 42 of the intermediate gears is fixed in the casing 1 of the whole mechanism and that of the upper gears 50, 51 in a quadrant 43 rotatable about the axis 42 by a hand-wheel 45 to displace the gear 31 relatively to the gear 30 and thereby displace an arm (not shown) which is secured to the gear 31. The ring E is balanced by an identical ring E' and each ring is pivoted at i to a link m forming the intermediate member of a three-part linkage l ... n, the ends of which are pivoted to the spokes of the framing D. Pivoted to the intermediate link m is an oval O, and the line joining the pivots i, j is perpendicular to the line joining the pivot points on the link m. The uniform rotation of the framing D combines with the non-uniform rotation of the pivot i about the shaft B to give the pivot a straight-line radial movement, the displacement of the oval O also being rectilinear. Links 28 connect the oval O to clutch rings 8 ... 11 which surround links F, G on the shaft B and by rotating forwardly at alternately faster and slower speeds in successive quadrants of the rotation of the eccentric rings E cause continuous rotation of the shaft B, the rotation being uniform since the pivots of the links 28 on the oval, which actuate the clutch arms 8 ... 11 are offset from a radial line parallel to other movement by a distance equal to 1.345 times the radius of the clutch arm, the link having a length of 1.749 times that radius.