Improvements in the Construction of Sprocket Wheel and Chain Gearing.
Year: 1895

page_text: Date of Application, 4th Nov., 1895
Complete Specification Left, 31st July, 1896-Accepted, 19th Sept., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Sprocket Wheel and Chain
Gearing.
WILLIAM ANDREWS and HENRY PATTMAN TRUEMAN both of Victoria Cycle Works,
21 Victoria Road, Aston, Birmingham, Engineers, do hereby declare the nature of
this invention to be as follows:-
Our invention relates to the construction and adjustment of sprocket wheels,
commonly used in conjunction with a link chain for the purpose of communicating
motion or work from one place to another, and consists of means whereby the pitch
line of the sprocket wheels and the distance between the driving and driven shafts
can be adjusted to compensate for the increasing pitch of the chain due to the natural
wear of the links.
We have found by calculations and experiment, that the pitch lines of the wheels
have to be increased in proportion to their diameter, and that the distance between
the shafts has also to be increased in proportion to the length of the chain running
thereon.
One method of carrying our invention into effect is to provide an adjustable flange
on each side of the teeth of a sprocket wheel, for the purpose of forming a bed for the
chain to lay upon while the spaces between the links engage with the teeth of the
said sprocket wheel.
These flanges have inclines formed on their edges, so that when adjustment is
made by turning the flanges, the effect is to increase or reduce the diameter of the
pitch line of the wheels. The flanges are or may be graduated to indicate the
diameter to which they may be set. The teeth of the sprocket wheels are or may
be made to take up wear by constructing the body of the teeth in half sections which
can be moved upon each other as required. We prefer in such cases to make the
edges of the sections overlap each other so as to present the full width of tooth bearing,
which will be in contact with the chain.
The shafts carrying the sprocket wheels are or may be provided with a graduated
scale by means of which the shafts may be set wider apart or closer together, to suit
the proportionate wear of each tooth multiplied by the number of links in the chain
not in contact with the sprocket wheels.
Our invention is applicable to all kinds of chain and sprocket wheel gearing, but is
specially applicable to chains of small pitch such as used for cycles and road carriages.
Dated this 2nd day of November 1895.
Improvements in the Construction of Sprocket Wheel and Chain
Gearing.
.
WILLIAM ANDREWS and HENRY PATTMAN TRUEMAN both of Victoria Cycle Works,
21 Victoria Road, Aston, Birmingham, Engineers, 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 relates to the construction and adjustment of sprocket wheels,

page_text: commonly used in conjunction with a link chain for the purpose of communicating
motion or work from one place to another, and consists of means whereby the pitch
line of the sprocket wheels and the distance between the driving and driven shafts
can be adjusted to compensate for the increasing pitch of the chain due to the
natural wear of the links.
We have found by calculations and experiment, that the pitch lines of the wheels
have to be increased in proportion to their diameter, and that the distance between
the shafts has also to be increased in proportion to the length of the chain running
thereon.
One method of carrying our invention into effect is to provide an adjustable flunge
on each side of the teeth of a sprocket wheel, for the purpose of forming a bed for
the chain to lay upon while the spaces between the links engage with the teeth of the
said sprocket wheel.
These flanges have inclines formed on their edges, so that when adjustment is made
by turning the flanges, the effect is to increase or reduce the diameter of the pitch
line of the wheels. The flanges are or may be graduated to indicate the diameter to
which they may be set. The teeth of the sprocket wheels are or may be made to take
up wear by constructing the body of the teeth in half sections which can be moved
upon each other as required. We prefer in such cases to make the edges of the
sections overlap each other so as to present the full width of tooth bearing, which will
be in contact with the chain.
The shafts carrying the sprocket wheels are or may be provided with a graduated
scale by means of which the shafts may be set wider apart or closer together, to suit
the proportionate wear of each tooth multiplied by the number of links in the chain
not in contact with the sprocket wheels.
Our invention is applicable to all kinds of chain and sprocket wheel gearing, but
is specially applicable to chains of small pitch such as used for cycles and road
carriages.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is an elevation of a pair of sprocket wheels and chain constructed according
to this invention.
Fig. 2 is a section of the large sprocket wheel C.
Fig. 3 is an enlarged view of a segment of a sprocket wheel shewing the chain link
resting on the minor pitch line and one link on the major pitch line.
Similar letters and figures refer to the same parts throughout the drawings.
In Figs. 1 & 2 C is the sprocket wheel, D D are two flanges having serrated edges e.
The two flanges are preferably annular and rest upon shoulders F formed on the arms
of the wheel C. The two flanges D D are connected by shouldered rivets 9-
preferably passing through a slot in the arms of rim of the sprocket wheel C. At h
Fig. 1. are shewn a series of holes in the flanges and in the rim. The hole h 1 in
the flanges coincides with the hole in the rim. The hole 2 in the rim is about
one fifth (of the whole movement required) to the left of the hole 2 of the flange.
h3 is ths h45 to the left of the 5th hole in the flange. The plates or side
links k of the chain are preferably formed with inclines agreeing with the serrated
edges of the flanges D D. The blocks M-are or may be formed with similar inclines
on their under surface when it is desired that the said block M should rest on the
inclined edges of the serrated flanges D D.
Fig. 1 shews an adjustable back fork end of a cycle adapted to carry the axle
of the small sprocket wheel T shewn in Fig. 1.
By turning the nut N the axle is moved a distance indicated by the graduated
scale P Fig. 14 shewn in the drawing.
The scale P is preferably adjustable by means of the differential holos R¹ R2 R³.
We will now describe the method of operating the devices which form the subject
of this our invention. Assuming the chain to be exactly 1' pitch when new; the
serrated flanges are set in the position shewn in Fig. 1; by placing a screw in the
hole 1 of each sprocket wheel. The axle of the small sprocket wheel would also be

page_text: adjusted fixing the graduated scale by a screw fixed in the hole R1 and the index
made to read zero. If the chain connecting the sprockets consist of 50 one inch links,
a total lengthening due to wear of one inch of the chain would represent an increase
in pitch of of an inch. To produce this increased pitch line the serrated flanges
would be moved round and fixed by the screw being placed in the holes 5 of both
sprocket wheels. The chain links would then occupy the major pitch line of
1 + 3 = 13 of an inch, as shewn at S Fig. 3. The increased pitch of th for
each link not being in contact with the sprocket wheels would be taken up by moving
the axles further apart by the screw N shewn in Fig. 1. The exact amount is ascertained
by inspecting the graduations P. The said graduations are preferably numbered to
agree with the holes h1 to h 5 of the wheels. If it is desired to widen the teeth of the
sprocket wheels to take up any "back lash" which may exist the sprocket wheels are
or may be made in halves, but we make no claim for novelty as to this part of our
invention, save only when used in conjunction with the serrated flanges herein
described and illustrated.
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 :-
:-
1st. The device of a toothed sprocket or chain wheel having serrated flanges adapted
to increase the pitch line of a chain working thereon; substantially as herein described
and illustrated.
2nd. The construction and use of graduated scales or stepped holes (whereby the
exact distance required between the axes of chain wheels can be determined) in
combination with the wheels described in the foregoing claim.
3rd. The construction and use of a chain having blocks or having links adapted to
engage with inclines formed on adjustable flanges, substantially as herein described
and illustrated.
Dadth: 20th dow of T1, 1906
HENRY PATTMAN TRUEMAN.
WILLIAM ANDREWS.