Patent GB-191211494-A (GB)
Title: Improvements in or relating to Variable Speed Gearing.
Inventor: TARRISSE MATHURIN
IPC: F16H15/10
Filed: 1911-06-13
Granted: 1913-07-14
Abstract: 11,494. Tarrisse, M. June 13, 1911, [Convention date]. Automatic Speed or p o w e r c o n t r o l; governors, applications of.-Relates to variablespeed and reversing friction-disk gearing for motor-vehicles, of the kind in which the driven roller is caused to slide on its shaft to vary the speed ratio by displacing the shaft in relation to the axis of the driving disk, or conversely; and comprises a n arrangement i n which such displacement is effected automatically under the control of a speed governor on the motor shaft. The action of the disk and roller is shown diagrammatically in Fig. 2. A roller 3, situated in the quadrant I of a disk rotating in the direction of the arrow F, is subjected to a rotative force and also to an axial force tending to displace it along its shaft towards the periphery of the disk. In the quadrant II, the rotative force is in the same direction, but the axial force tends to displace the roller towards the diameter B, B<1> of the disk. The action is similar in the quadrants III and IV, but the direction of rotation of the roller is reversed. An embodiment of the device in the variable-speed gear of a motor-vehicle is shown in Figs. 4 and 7. The roller 12, in engagement with the disk 1 driven by the motor 2, is slidably mounted upon a shaft 11, which is raised or lowered in a plane parallel to the disk 1 by the action of a centrifugal governor 3 rotating with the motor-shaft 2. The adjustment of the shaft 11 varies the position of the roller in relation to the disk as described with reference to Fig. 2, such displacement from the neutral position causing the roller to slide along its shaft towards or away from the periphery of the disk, thereby varying the speed ratio. The effect of the arrangement is that a fall in the motor speed causes the roller 12 to travel towards the centre of the disk 1, reducing the gear ratio to permit the motor to regain its normal speed. The shaft 11 is mounted in slide guides, and is pressed towards the disk 1 by springs. Its position is adjusted by means of a member 24, at each end, provided with ball-mounted rollers 25 engaging a cam-shaped aperture 25<1> in a slidable plate or frame 23 guided by rollers 27. The frames 23 are moved to raise or lower the shaft 11 by means of links 22 connected to crank arms 21 on shafts 20, each shaft 20 having opposite crank arms 18, 19 connected to pivoted links 8, 9, the hooked ends 10<a>, 11<a> of which are adapted to engage respectively with pins 6, 7 formed on lateral extensions of a collar 5 sliding on the motor shaft 2 and connected to the centrifugal governor 3. The links 8, 9 are guided by a transverse frame 16 pressed by means of springs 17 against a slidable adjusting- member 33, connected to an actuating-lever 32 and having surfaces 34, 35, which determine the engagement of the hooked ends 10<a>, 11<a> with the pins 6, 7 respectively, the position shown in Fig. 7 corresponding to forward drive. Positive actuation of the roller 12 may be effected by means of the lever 32, which is free to follow the automatic movements of the roller and is connected thereto by a link 71 and bell-crank 72. In effecting reversal, the lever raises the frame 16 by means of the raised part 35 of the member 33, thereby disconnecting the links 9 and connecting the links 8 to the pins 6 on the governor-operated collar 5. This renders the device, responsive to automatic governor control while driving in the reverse direction. In order to raise the shaft 11 into the ' neutral ' position corresponding to that indicated in quadrant IV, Fig. 2, the pins 6 are so disposed that, to effect engagement, a slight tilt of the crank-arms 18 is necessary, this causing the guide-frames 23 to be moved sufficiently to raise the shaft 11 into the required position. In order to prevent the roller 12 from automatically passing across the centre of the disk 1, a spring stop 54 is provided which detains the lever 32 until such lever is positively actuated. In order to ensure a vertical disposition of the crank-arms 18, 19 while effecting reversal, a foot pedal 31, which, through a crank-arm 65 and link 66, relieves the pressure of the roller 12 against the disk, also acts through an adjustable stop link 36 and lever 38 upon a grooved sleeve 4 to forcibly bring the governor running at a low speed to the required position, corresponding to normal speed, in which the crank arms are vertical. The device may be modified by rendering the disk the adjustable member or the roller the driving-member.