Improved Driving Gear for Cycles.
Year: 1892

page_text: Date of Application, 10th Aug., 1892
Complete Specification Left, 8th May, 1893-Accepted, 17th June, 1893
PROVISIONAL SPECIFICATION.
Improved Driving Gear for Cycles.
WILLIAM THOMAS SHAW Director, and ARTHUR SYDENHAM Works Manager
of The Crypto Cycle Company Limited of No. 64, City Road London, E.C. do
hereby declare the nature of this invention to be as follows:-
:-
Our invention consists in an improved driving gear for cycles whereby the
movement imparted to the axle of a wheel is caused to rotate the wheel itself at an
increased velocity. Our improved means of effecting this end may be described as
follows:-
The driving wheel of a bicycle or tricycle is not built as one connected piece,
but is made up of the following distinct parts, viz. The hub proper, with its
attached spokes, rim and tyre; the axle, with its cranks and pedals; and a train
of wheels connecting the hub and axle so contrived as to give a different velocity
ratio of the one to the other. When it is desired that one revolution of the
crank-axle shall cause two revolutions of the hub, the construction is as follows.
The hub at one end carries a flange of the ordinary form for the reception of the
spokes, and the fork-end on this side of the wheel is also of the usual construction.
The continuation of the hub towards the other side of the wheel takes the form of
a short tube ending in a broad annular disc, at right angles to the short tube. The
disc at its periphery bends over and forms a broad flange terminated at the side
next the opposite fork by a narrow projecting flange carrying the spokes on that
side. The enlargement of the hub just described forms, it will be seen a cylindrical
gear-box, which is closed in on the side next the fork by a circular lid or cover.
This box contains the mechanism connecting the axle with the hub, as follows: The
hub-disc on the inside carries a spur-wheel supported by a ball-bearing on the axle, the
width of the spur-wheel being about one-third of the total width of the cylindrical
gear-box. Projecting into the latter, and formed in one piece with the fork-end
bearing on that side, is a fixed spur-wheel of the same size and thickness as the one
previously mentioned. These two spur-wheels, the one fixed to the fork, the other
in one piece with the hub, are separated by a space equal to the width of the spur-
wheels respectively; and the axle, which passes through them centrally, at the
part lying between them is enlarged into a circular web of the same diameter as
the two spur-wheels. At its outer periphery this web carries a cylindrical double
flange sailing over the spur-wheels on either side, and cut away to the necessary
extent to admit of the engagement of the driving pinions with the spur-wheels as
explained below:-The double flange is terminated by annular discs projecting
outwards towards the cylindrical portion of the gear-box. These annular dises or
walls carry two pairs of broad pinions, called by us driving pinions, constructed as
follows. Each pinion is made of a width twice as great as that of the spur-wheels
first described. Consequently, a driving pinion gearing with the fixed spur-wheel
has half its width disengaged. This is caused to gear with the disengaged half of
a similar driving pinion the other half of which engages with the spur-wheel fixed
to the hub. In order to divide and balance the strains, we place a similar pair of
driving pinions on the opposite side of the fixed and hub spur wheels; and for the
purpose of diminishing friction ball-races are interposed between the driving pinions
and their respective spindles at either end. The effect of a train of wheels
constructed and mounted as herein described is that when the crank axle is rotated
the driving pinions are carried round therewith and rotate the hub of the road
wheel in the proportion of two revolutions of the latter to one revolution of the

page_text: axle whilst, obviously by adopting different proportions for the several components
of the train of wheels, the velocity-ratio may be varied in a corresponding degree.
Dated this Tenth day of August 1892.
WM. THOS. SHAW.
ARTHUR SYDENHAM.
COMPLETE SPECIFICATION.
Improved Driving Gear for Cycles.
WILLIAM THOMAS SHAW Director, and ARTHUR SYDENHAM, Works Manager,
of The Crypto Cycle Company Limited of No. 64 City Road, London E.C. 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 an improved driving gear for cycles whereby the
movement imparted to the axle of a wheel is caused to rotate the wheel itself at
an increased velocity. Our improved means of effecting this end may be described
as follows: The driving wheel of a bicycle or tricycle is not built as one
connected piece, but is made up of the following distinct parts, vi. The hub
proper, with its attached spokes, rim and tyre; the axle with its cranks and pedals;
and a train of wheels connecting the hub and axle so contrived as to give a different
velocity ratio of the one to the other. When it is desired that one revolution of
the crank-axle shall cause two revolutions of the hub, the construction is as
follows: The hub H at one end carries a flange of the ordinary form for the
reception of the spokes, and the fork-end K on this side of the wheel as also the
ball bearings, are of the usual construction. The continuation of the hub towards
the other side of the wheel takes the form of a short tube T ending in a broad
annular disc, C, at right angles to the short tube. The disc C at its periphery
bends over and forms a broad flange L terminated at the side next the opposite
fork K by a narrow projecting flange on hub H carrying the spokes on that side.
The enlargement of the hub just described forms, it will be seen, a cylindrical gear
box, which is closed in on the side next the fork K' by the annular disc N described
below. This box contains the mechanism connecting the axle A with the hub H
as follows. The hub-disc C on the inside carries a spur-wheel D supported by a
ball-bearing B on the axle, the width of the spur wheel being nearly one-third of
the total width of the cylindrical gear-box. Projecting into the latter, and formed
in one piece with the fork-end bearing K¹ on that side, is a fixed spur-wheel F of
the same size and thickness as the one previously mentioned. These two spur-
wheels, the one fixed to the fork, the other in one piece with the hub, are separated
by a space slightly exceeding the width of the spur-wheels respectively; and the
axle A which passes through them centrally at the part lying between them is
enlarged into a circular web W of the same diameter as the two spur wheels F
and D.
At its outer periphery this web carries a cylindrical double flange Y sailing
over the spur-wheels on either side and cut away to the necessary extent at M
Fig. 11 to admit of the engagement of the driving pinious P with the spur-
wheels F and D as explained below. The double flange Y is terminated by
annular discs N and N₁ projecting outwards towards the cylindrical portion of the
gear-box. These annular dises or walls N and N¹ carry the spindles S of two
pairs of broad pinions P as shown by dotted lines Fig. 11 and Fig. III called by
us driving pinions constructed as follows:-Each pinion is made of a width twice
as great as that of the spur-wheels first described. Consequently a driving pinion
gearing with the fixed spur wheel F has half its width disengaged. This is caused
to gear with the disengaged half of a similar driving pinion, the other half of
which engages with the spur-wheel D fixed to the hub." In order to divide and
balance the strains, we place a similar pair of driving pinions on the opposite side

page_text: of the fixed and hub spur-wheels as shown in Fig. III and for the purpose of
diminishing friction, ball-races B' are interposed between the driving pinions and
their respective spindles at either end. The effect of a train of wheels con-
structed and mounted as herein described is that when the crank axle is rotated
the driving pinions are carried round therewith and rotate the hub of the road
wheel in the proportion of two revolutions of the latter to one revolution of the
axle, whilst, obviously by adopting different proportions for the several com-
ponents of the train of wheels, the velocity ratio may be varied in a corresponding
degree.
Fig. III (Sheet II) for example, shows a train of wheels by means of
which one revolution of the axle gives 1-9 revolutions (nearly) of the hub of road-
wheel. The same parts are indicated by the same letters as on Sheet I. The
spur wheels F and D are of equal diameter but their respective pinions are
unequal, the one which gears with F having 14 teeth and the one gearing with D
13 teeth; whilst both pinions where they gear with each other carry 13 teeth.
Suppose these pinions to be reversed, end for end, and interchanged, the velocity
ratio of the axle and the hub of road-wheel becomes altered and one revolution of
the axle gives 2.1 revolutions of the road-wheel. Different ratios may also be
obtained by making the fixed and hub spur-wheels differing from one another as to
the number of teeth instead of their being equal as in the combinations given
above, the pinions in that case being also varied as to the number of their teeth, in
accordance with the well-known rules of computation applicable in such cases.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed we declare that what we
claim is
An improved driving gear constructed and applied substantially in the manner
and for the purposes herein illustrated and described.
Dated this 3rd day of December 1892.
WM. THOS. SHAW.
ARTHUR
SYDENHAM.