Fifteen speed variable radius bicycle transmission
AssigneeExeter Granddiorite Trust
InventorJames F. Pritchard
Life of this patent
Estimating the term…
Abstract
A fifteen speed bicycle transmissiion wholly located on the rear driving wheel except for a manual control mounted elsewhere, e.g. on the handle bar, and including two closely arranged circular co-axial plates on the hub, one plate being a drive plate with radial slots and the other plate being a cam plate with curved slots, and sprocket elements each located in a combined curved and straight slot for radial adjustment upon rotary motion between plates, and locking member including notches and pawls on the plates at the peripheries thereof and actuated to unlock the plates by the control.
Claims15
A bicycle transmission for a bicycle having a drive wheel and a chain to drive it, comprising a drive plate fixed with relation to the drive wheel, a cam plate in parallel side by side co-axial relation to the drive plate, radial mutually spaced slots in the drive wheel, corresponding curved cam slots in the cam plate, sliders, said radial slots and cam slots cooperating in pairs to accommodate a slider in each pair of slots whereby relative rotational motion of the plates causes the sliders to be moved radially, chain engaging sprockets on two only diametrically opposed sliders, the chain being engaged with one sprocketted the slider and trained over the other sliders,
- notches at the periphery of the cam plate, said notches being mutually spaced, a locking pawl on the drive plate in position to lock the plates together by engagement with a notch, means to temporarily disengage the pawl from the notch, means normally urging the pawls toward plate locking position,
- and means to cause relative rotation of cam plate and drive plate while the pawl is disengaged.
A bicycle transmission for a bicycle having a drive wheel and a drive chain therefor, comprising
- a circular co-planar series of elements over which the chain is arranged, said elements being radially adjustable relative to the drive wheel, and means connecting the elements to the drive wheel to drive the latter under influence of the chain regardless of the radial adjusted positions of the elements,
- means to releasably secure the elements in selected radial positions of adjustment relative to the drive wheel,
- sprocket teeth to engage the chain on at least one of said elements, the remainder of the elements being free of such teeth, the elements being arranged to allow interengagement of but one element having sprocket teeth with the chain.
A bicycle transmission for a bicycle having a drive wheel, a bicycle drive chain to drive it, and a hub on the wheel,
- said transmission comprising a drive plate fixed with relation to the hub, a cam plate on the hub but free thereof, said plates being closely adjacent, flat, and co-axial,
- a spring connecting said plates to cause relative rotation thereof and means to lock the plates together preventing such rotation, manually actuated means to release the locking means, and spring means normally urging the locking means toward locked position,
- a series of mutually spaced radial slots in the drive plate and cooperating similarly curved slots in the cam plate, each cam plate slot being intersected by a drive plate slot,
- a slider in each pair of cooperating cam and plate slots, the sliders being equally moved radially by relative motion of the plates, the chain being trained over said sliders for approximately one-half a circle defined by the sliders as a group, chain engaging sprockets on only two of said sliders, the latter being diametrically opposed so that the chain can engage only one slider at a time,
- the locking means comprising a series of notches on one plate and a pair of diametrically opposed notch-engaging pivoted pawls on the other plate, the notches equaling in number the number of speeds the transmission has,
- and said notches extending about the peripheral area of the plate they are on.
Dependencies are inferred from the claim text.