Patent GB-704679-A (GB)
Title: Improvements in continuously variable speed gears of the frictional type
IPC: F16H15/40
Filed: 1951-03-06
Abstract: 704,679. Variable-speed gearing. SOC. ANON. GEOFFROY-DELORE. March 6, 1951 [March 7, 1950], No. 5357/51. Class 80 (2) A continuously, variable speed gear comprises spaced coaxial driving and driven discs 3, 4, Fig. 2; a ball 5 tangent thereto at "first points" which define "first radii " of the ball which form, a "first angle" in a "first plane", rollers 6, 7 tangent to the ball at "second points" which define " second radii " of the ball which form a "second angle" in a "second plane" the roller axes being normal to the second radii said first plane being normal to said second plane and said first angle being substantially equal to said second angle and having a bisectrix common therewith each roller being mounted for pivotal movement about its respective second radius, and means for imparting predetermined equal and opposite angular displacements to the rollers about their respective second radii to vary the velocity ratio. When the axes of rollers 6, 7, are parallel the ball 5 rotates about an axis parallel to the axis of discs 3, 4 and the velocity ratio' is unity. On angular displacement of the rollers about the second radii their axes meet at a point P and the ball is constrained to rotate about an axis passing through its centre and that point thus allowing any, velocity ratio tg be obtained between +α and -α depending on the position of P. Figs. 4-6 (not shown) illustrate, simple practical embodiment. In a further embodiment, . Figs. 8, 9, stated to be applicable to motor vehicles, a plurality of ball members transmit the drive. Eight balls 26 are arranged with their centres at the apices of two squares lying in spaced parallel: planes. Each ball contacts a driving member 30 and one of two driven members 28, 29 which rare urged together by a:device 35. Eight rollers 31 are disposedbetween the balls. 26 which they contact at points lying on lines joining the ball centres. Each roller may rotate about its axis and is carried in a cage 32 journalled on ball bearings 33 in a fixed block 27. Gear teeth 34 on each cage 32 engage teeth 38 on a cylindrical member 37 which may be displaced longitudinally by means of a control lever 39 working in a gate 48, to angularly displace the rollers 31. An automatic device arranged to maintain constant the speed of the driving member independent of the torque on the driven member comprises an intermediate member 43 having longitudinal and helical grooves in its inner and outer surfaces respeclively, balls engaging those grooves and complementary grooves in an engine driven member 42 and in the gear driving member 30, centrifugal weights 44 on bell cranks 47 pivoted to the member 43 at 46, and connection between the member 43 and the roller orientation control rod 36. The centrifugal-weight speed responsive device may be replaced by means actuated by the engine lubricating oil pump, the pressure generated thereby being approximately proportional to the speed. The gate 48 has three slots Fig. 11, (not shown) one allowing free-movement of the lever 39 in response to movements of the automatic control device -and the others maintaining the lever in either the zero output speed position or in a fixed reverse speed position.