An Improved Variable Power Gear for Bicycles.
Year: 1896

page_text: Date of Application, 22nd Dec., 1896-Accepted, 27th Feb., 1897
COMPLETE SPECIFICATION.
An Improved Variable Power Gear for Bicycles.
I ALAN DE TATTON EGERTON of Rostherne Manor Knutsford in the County of
Cheshire, Member of Parliament do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
.
My improved variable power gear for bicycles has for its object the giving to
riders of these machines means whereby they can alter mechanically the power
required to work the driving wheel without varying the speed of the movements
of their legs, and also enables the power required for the bicycle to be adapted to
suit the varying conditions of the roads travelled over.
The improved variable power gear is constructed as follows:--To one side of
the hub of the driving wheel of the bicycle, outside the spokes, is attached a bevel
wheel, and geared into this is another bevel wheel, at right angles with the former,
secured to a hollow shaft (a) in a line with the centre of the driving wheel and the
centre of the treadle axle (b); this shaft works on and outside the frame and is
held in bearings (c) attached to the frame of the bicycle; on the treadle end of the
shaft is a bevel pinion wheel (d) which gears into a bevel wheel (e) of larger
diameter than itself; the larger bevel wheel is secured to the treadle axle (b)
which works in ball bearings; the outer casing hereinafter called the ball
socket (f) containing the balls is so shaped as to permit of its sliding simultaneously
in a horizontal and lateral direction within the treadle socket.
These two motions are obtained by providing the ends of the ball socket (f)
with parallel bevelled guides (9) working between wedges (h) attached to the ends
of a forked rod (i). There are four wedges in all, two embracing each end of the
ball socket, and by raising and lowering them lateral motion is obtained.
The fork just mentioned moves vertically in guides (o) on each end of and
forming part of the treadle socket, which constructed with a parallel sided semi-
circular ended opening within it, wherein the ball socket travels horizontally. The
faces of the parallel wedges of the fork are set at such angles that in their vertical
traverse they produce horizontal and end-way motion of the ball socket.
The rod (i) attached to the fork is carried up as a single bar until it meets the
top of the framing of the machine, supposing the framing to be of the ordinary
diamond pattern form, where it passes through a socket (k) and milled nut (1)
which is kept in position by being partly let into the socket and by being secured
in place by means of a garter (m) and pins (n). The upper part of the forked rod
is screwed, and the nut just spoken of is tapped to fit it. By turning the milled
nut (1), which can be moved in either a right hand or left hand direction, an up or
down vertical motion can be given to the forked rod (), and by means of the
wedges (h) at the ends, a horizontal and traversing motion of the ball socket (f)
is given.
This combined action of the wedges (h) at the lower ends of the forked rod (i)
causes the ball socket (f) and with it the treadle axle (b) and bevel wheel (e) to
travel in a horizontal direction more or less across the face of the small bevel
wheel or pinion (d) and the wheel (e) to keep in gear with it.
When the bevel pinion (d) on the hollow shaft (a) is situated near to the centre
of the treadle spindle, owing to the latter having been moved towards it, an
increase of hill climbing power will be obtained.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The apparatus hereinbefore described for varying by mechanical means the
power requisite for propelling toothed bevel wheel gear driven velocipedes.
2. The combination of a forked rod, working in guides, that has attached to it
four wedges, with two inclined faces to each at right angles to one another, and
working in guides on the treadle socket or bracket of a bicycle and bearing
against the inclined faces of a moveable socket holding the treadle axle which
socket is contained within an opening in the treadle socket or bracket and is
capable of sideway and endway movement at one and the same time; and a bevel
wheel fixed to the treadle axle for use with toothed bevel wheel gear driven
.bicycles.
Dated this 22nd day of December 1896
E. H. G. BREWSTER,
Agent for Applicant.