Back to results
US 3,934,481 AGranted
Automatic friction drive transmission
OwnerDonald A. Fosterinventor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerDonald A. Fosterinventor
Estimating the term…
A transmission for a pedal-propelled vehicle has a drive shaft rotated by a crankset and disposed radially with respect to the driving wheel of the vehicle. A friction wheel is slidably connected to the shaft by a one-way clutch and is in engagement with a friction member connected to the driving wheel to rotate therewith. The friction wheel includes a tubular shaft through which the drive shaft extends. A shifting unit is connected to the friction wheel by means of the tubular shaft to slide along the drive shaft therewith but is held against turning. The shifting unit includes a gear train having a pinion in mesh with a fixed rack parallel to the drive shaft. First and second normally inoperative connections between the tubular shaft and the gear train are provided, the first to drive the gear train to rotate the pinion to shift the unit and the friction wheel towards the axis of the friction member and the second to drive the gear train to shift the unit and friction wheel towards the periphery thereof. The connections are made by a control including means responsive to the speed of the tubular shaft and means, adjustable by the operator, resiliently opposing the speed responsive means. When the speed responsive means is dominant, the first connection is rendered operative, when the resilient means is dominant, the second connection is rendered operative, and when neither means is dominant, a neutral is established with neither connection operative, the transmission thereby effecting ratio changes in relation to the wanted rate of pedalling or cadence that is established by the resilient means.
A transmission for a vehicle of the type having a wheel to which power is to be applied to rotate it and a drive to provide wheel-turning power, said transmission including a friction member coaxially mounted with respect to said wheel to rotate therewith, a drive shaft disposed close to and radially with respect to the friction member and connected to said drive, a unit slidably mounted on said shaft with said shaft rotatable independently thereof, a friction wheel, means connecting said friction wheel to said shaft to slide therealong and to rotate therewith when the shaft is rotated in a direction to advance the vehicle, said friction wheel and said unit connected to move together along said shaft, the periphery of the friction wheel in engagement with said friction member, the ratio of revolution between the shaft and the friction member dependent on the radial position of the friction wheel relative to the friction member, said unit including means operable to shift said friction wheel and said unit along said shaft and having first and second connections with said friction wheel, the first operable to cause said shifting means to move said friction wheel and said unit in a direction to increase said ratio and the second operable to cause said shifting means to move said friction wheel and said unit in the opposite direction to decrease said ratio, said unit also including a control to actuate said shifting means to maintain the rotation of the shaft substantially constant at a predetermined rate, said control including first means responsive to the speed of the friction wheel and second means providing predetermined yieldable opposition to the first control means, said first and second control means coacting to actuate said shifting means to render said first connection operative if the friction wheel speed is above said predetermined rate thereby to permit a decrease in shaft speed until it reaches said predetermined rate and to render said second connection operative if the friction wheel speed drops below said rate thereby to permit a higher shaft speed appropriate for the slower rate at which said vehicle wheel turns.
Dependencies are inferred from the claim text.