An Improvement in the Sprocket Wheel applied to Cycles.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
An Improvement in the Sprocket Wheel applied to Cycles.
I, HORATIO MARSH WARD, of Eleven, Lowe Street, in the County-Borough of
Saint Helens, Lancashire, Cutlery Grinder, &c., do hereby declare the nature of
this invention to be as follows:
My invention relates to an improvement in the sprocket wheel applied to cycles.
Unlike the present wheel, it is not circular, but is an ellipse wheel (again unlike
the former circular wheel) having two unequal diameters. When in motion the
rotation of the wheel is irregular, as will be understood when in connection with the
driving wheel of the cycle by means of a chain. The speed of the wheel will be
greatly increased when its transverse diameter becomes horizontal, or in a parallel
line with the chain, the cranks being attached at right angles with the transverse
diameter will pass this point quickly, but as the wheel revolves the conjugate
diameter will become horizontal & the transverse diameter vertical, thus the speed
of rotation will be greatly decreased, and the time for impulse will be prolonged,
less exertion will be required and a greater speed will be attained.
Dated this Twenty-fourth day of September 1897.
An Improvement in the Sprocket Wheel applied to Cycles.
I, HORATIO MARSH WARD, of 11, Lowe Street, in the County-Borough of
Saint Helens, Lancashire, Cutlery Grinder, &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:-
My invention relates to an improvement in the sprocket wheel applied to cycles.
Unlike the present wheel, it is not circular, but is an ellipse wheel, having two
unequal diameters, (again unlike the former circular wheel.) When in motion
the rotation of the wheel is irregular, as will be understood when in connection
with the driving wheel of the cycle by means of a chain.
The speed of the wheel will be greatly increased when its transverse diameter
becomes horizontal, or in a parallel line with the chain, the cranks being attached
at right angles with the transverse diameter, will pass this point quickly, but as the
wheel revolves the conjugate diameter will become horizontal and its transverse
diameter vertical, thus the speed of rotation will be greatly decreased and the
time for impulse will be prolonged, this will be clearly understood by the
annexed Fig. I.

page_text: A is the ellipse wheel having an even number of teeth or sprockets, B the crank,
CC the chain, and D the driving wheel. The crank is here shown horizontally or
in a position when the impulse is given with the foot, as the crank descends the
radius of the wheel A gradually diminishes and the circuit of the chain becomes
shorter, this would greatly relax the tension of the chain but for the intervention
of a sectional combination of protuberant links F which mesh with the teeth or
sprockets of the minor radii SS of the ellipse wheel A.
The chain as shown in Fig. II is composed of sections F and H which vary in
thickness successively but, being of the same breadth, as shown in Fig. III.
Sections H are composed of a thin series of links which fit on the major radii R R
of the wheel A Fig. I, the other sections F are composed of a thick or protuberant
series of links which fit on the minor radii S S of the wheel A Fig. I.
The chain may be graduated by a tapering or conical link j as shown in Fig. II
inserted at jj of each section F as shown in Fig. I.
The wheel A. as shown in Fig. I is covered by one of the sections F while the
small. rear wheel N will be covered by one of the thinner sections H, but if the
crank B be turned to the star K two of the sections F will be covering the wheel A
and a third section F will be covering the wheel N, a slight refraction having
taken place in the line of tension. The two wheels A and N alternately perform
this function working mutually with each other taking up the slack of the chain,
maintaining a uniform tension and producing alternately accelerated and retarded
circular motion. To maintain an alternate engagement of sections F and H on
the radii of the wheel A the teeth or sprockets must be arranged in an even number
as an uneven number will not perform this function. Fig. I shows the ellipse
wheel A with an even number of teeth or sprokets, any even number of teeth may
be used according to the gear required. The sideplates of the chain may be made
uniformly alike providing a protuberance of the blocks or rollers of the chain are,
sectionally arranged.
If the roller chain be used a protuberance of the rollers must be sectionally
arranged:
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:-
I. The ellipse wheel having an even number of teeth or sprockets.
II. In combination with the chain wheel claimed in Claim I a sectional arrange-
ment of protuberant links, blocks or rollers inserted in the chain which produce
a uniform tension.
III. Accelerated and retarded circular motion of the cranks.
Dated this Twenty-eighth day of September 1897