Improvements in Driving Mechanism for Bicycles, Tricycles, and the like.
Year: 1898

page_text: Complete Specification Left. 28th May, 1898-Accepted, 27th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in Driving Mechanism for Bicycles, Tricycles, and
the like.
We, HENRY ATWELL PURDON, Civil Engineer, and HARRY ERNEST WALTERS, Civil
Engineer, both of 2, Great George Street, Westminster, in the County of
Middlesex, 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:-
Our invention consists in improvements in the driving mechanism of bicycles,
tricycles and the like, propelled by foot power.
The objects of our invention are to increase the efficiency of the power transmitted
through the pedals in driving cycles and the like, (the pedals in our invention
travelling in a path that approximately forms an elipse instead of a circle) and to
provide a simple and efficient speeding mechanism or driving gear for chainless
cycles.
Hitherto in most instances the spindle of the sprocket or driving wheel of
cycles and the like has been supported in a bracket forming part of the frame,
from which the driving power is transmitted to the rear wheel or wheels by means
of an endless chain passing over and gearing into the sprocket or driving wheel and
pinion on the rear wheel and the required speeding has been determined by the
difference of the diameters and number of teeth of the driving and pinion
wheels.
We will now describe our invention, reference being made to the accompanying
drawings which illustrate our improved driving mechanism as applied to the rear
wheel of a bicycle.
Figure 1 is a side elevation of a bicycle fitted with our improved driving
mechanism, Figure 2 being a part sectional plan of the driving wheel showing our
improved driving mechanism.
Figures 3 and 4 are respectively a part side view and a plan of the driving
wheel showing a slightly modified form of the mechanism, comprising an
alternative method of providing the sliding fulcrum (hereinafter referred to) to
that shown in Figures 1 and 2.
The same letters refer to the same parts in the several figures.
Referring to Figure 2, the gear or cog wheel a is formed on or attached to a
circular box forming the hub of the driving wheel c of the machine, to which box
the lid d is attached; this lid d is shown screwed to the box and then securely
fastened. The speeding or driving mechanism and the spindle on which the driving
cranks are fixed are contained in this box or hub b. This speeding mechanism
consists of a casing h¹ having cranked arms e e¹ one of which arms el carries a
spindle on which are fixed toothed gearing wheels f1f2 the wheel gearing with
and driving toothed wheel a attached to the box or hub b. Toothed wheel or
pinion gears with toothed wheel g on the solid spindle g¹ to which the pedal
mechanism is attached. The spindles f and 9' are both provided with feathers or
keys and are passed through the driving wheel g and pinion f¹ respectively. When
the spindle g is rotated it drives the rear wheel of the cycle or the like, by means

page_text: devised for carrying the various parts of the mechanism of the speeding gear and
for the hub of the driving wheel to run upon.
We do not, therefore, claim an eliptical pedal path, per se, neither do we claim
per se a gearing box containing speeding mechanism for cycles, but having now
particularly described and ascertained the nature of our said invention and in
what manner the same is to be performed we declare that what we claim is :-
Driving mechanism for cycles and the like, consisting of the combination of a
pedal lever such as į pivotally connected to a crank arm on the driving axle or
spindle g', a pivoted counecting rod from an extension of said crank arm to a
swinging triangular frame such as on which is mounted an oscillating block or
friction wheel through or on which slides one end of a pedal lever such has j, a
toothed gear wheel g keyed on the driving axle or spindle g', pinion and gear
wheel mounted in a slotted arm or projection such as e¹ on a casing h¹ held fast
to the frame of the cycle said gear wheel engaging a gear a fixed to or formed on
the hub of the driving wheel, whereby motion is communicated to said driving
wheel, all arranged and operating substantially as herein described with reference
to the accompanying drawings.
Dated this 28th day of May 1808
JOHN P. O'DONNELL,
Fel. Chart. Inst. P.A., Agent.