Improvements in Chain Wheels.
Year: 1897

page_text: Improvements in Chain Wheels.
GEORGE HERBERT ALLISON, Dene Works, Fulwell, Sunderland, Engineer, do
hereby declare the nature of this invention to be as follows:-
A chain wheel for use on cycles & other machinery on which the chain bears at
centre of blocks by means of intermediate teeth or, raised parts as shown at (A)
on drawing. Also at centres of each link by means of a ledge projecting from
each side of each tooth, as shown on drawing at (G). The under parts of blocks
at ends & the ends of links being free from contact with the wheel. Thus reducing
the friction between chain & wheel to a minimum. In the ordinary way it is
the reverse.
I, GEORGE HERBERT ALLISON, of Dene Works, Fulwell, Sunderland, Engineer,
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:
This invention relates to improvements in chain wheels and has for its object to
construct the wheel in such a manner that the friction of the chain thereon is
reduced to a minimum, consequently enabling the pitch of the wheels to be
correctly maintained for a much longer time than has been found possible with
wheels as constructed hitherto.
The pitching of chain wheels is a matter that requires great care and is of
the utmost importance in ensuring the smooth and proper working of the chain
and it is to prevent the reducing of the body of the wheel by friction of the chain
and the grinding action caused by the presence of dirt, that my wheel has been
devised.
But in order that my invention may be more readily understood and easily
carried into effect I will proceed to describe the same with reference to the accom-
panying drawing which illustrates the rear chain wheel of a cycle constructed in
accordance with my invention, the chain being shewn with the side links on the
front side removed for the sake of clearness.
Referring to the said drawing I provide at each side of the teeth A of the
wheel B a step or projection C so arranged that the side links D of the chain can

page_text: rest thereon. The body of the wheel B is provided, in the spaces between the
teeth, with curved or other shaped projections E upon which the blocks F of the
chain bear.
It will thus be seen that the surface upon which the chain rests is large and well
divided, giving a good support to the chain and that there is also a free way for
the dirt which cannot possibly affect the working or increase the friction.
My said improved wheel gives a dead bearing and causes each block and link
to be laid on the part it bears, not ground on as is the case with ordinary wheels
in which the chain bears on them at circular or working parts of blocks (and
links if a shroud is employed).
With wheels constructed in accordance with my invention, by reason of their
not being materially affected by dirt, friction is considerably reduced; being pro-
portionately saved the greater the driving pressure upon the chain.
The chain will also work freely on to the wheels when quite tight, will run
with half the noise, will not get out of pitch so soon and will last much longer.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
The improved construction of chain wheel for driving cycles or for other driving
purposes, substantially as and for the purposes herein before described and shewn
in the accompanying drawings.
Dated this 21st 1 of t
100%
JOHNSONS,
Applicant's Agents, 115, St. Vincent Street, Glasgow.