Improvements in Chain Gearing for Cycles, and for Mechanism generally.
Year: 1898

page_text: Date of Application, 5th Oct., 1898-Accepted, 19th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Chain Gearing for Cycles, and for Mechanism
generally.
I, HERBERT SAMUEL DINGLE, of Beauvoir House, Higher Erith Road, Torquay,
Devonshire, Mechanical 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 for improvements in chain gearing for cycles and for mechanism
generally, has for its object an improved construction of the chain and sprocket
wheels whereby they are simplified, while at the same time the gearing of the
chain therewith is facilitated and friction is reduced. Furthermore, by this inven-
tion the life of the chain is lengthened, as it may be so arranged that each link
of the chain is only in gear with the wheel at every second or third passage of the
chain round the wheel.
According to this invention, the chain and sprocket wheels are not provided with
teeth on the whole of their peripheries but at intervals of three times the pitch of
the chain employed, so that in effect, every third tooth of an ordinary gear wheel
is allowed to remain the intermediate teeth being removed. By this arrangement
it is found that the chain gears with the wheels quite as efficiently as when all
the teeth are present, while friction is greatly reduced. Also owing to there being
several unengaged links between each tooth the chain is enabled to adjust itself
to allow for small inaccuracies of pitch consequent on wear and other causes. By
arranging the chain with a number of links not a multiple of three, it will be
seen that on each passage of the chain round the wheels the links to engage with
the teeth are changed thus reducing the wear of the chain and increasing its life.
It will of course be understood, that the teeth may be arranged at intervals of
twice or four times the pitch instead of at three times as above described, but
three is found to answer best in practice.
In order that this invention may be more readily understood reference is had
to the accompanying sheet of drawings which illustrates a bicycle gearing having
the chain and sprocket wheels constructed according to this invention.
The chain wheel A is provided with teeth a upon its periphery arranged at three
times the pitch apart so that as there are 6 teeth the wheel is equal to one of
ordinary construction having 18 teeth. The sprocket wheel B is provided with
teeth upon its periphery at twice the pitch apart so that, as there are four teeth,
the wheel is equal to one of ordinary construction having 8 teeth, and the gear
ratio, with a 28 inch driving wheel is equal to a 63 inch wheel, and a saving of
16 teeth upon the two wheels A and B is effected thus simplifying them and greatly
lessening the cost of production. The chain C is of ordinary construction, and as
will be at once seen every third link only engages with the teeth a of the wheel A
and every second link only with the teeth b of the sprocket wheel B. By arranging
the chain C with a number of links which is neither a multiple of three nor two,
such for instance as 47, each link will only engage with the teeth a of the wheel A
once on every third passage of the chain Cround the wheel A and with the teeth b
077

page_text: of the wheel B once on every second passage of the chain C thus greatly reducing
the wear of each link and increasing the life of the chain. Further, as several
unengaged links lie between each engaged link the chain is enabled to adjust
itself to a small extent to allow for slight inaccuracies of pitch resulting from wear
and other causes.
The construction of the wheels A B is in other respects the same as the wheels
at present in use.
Also, though this invention has been described with reference to cycle gearing,
it may also be applied for mechanism generally wherever chain gear is employed.
It will of course be understood that the teeth of the chain and sprocket wheels
may be arranged otherwise than at two or three times the pitch, for instance, the
chain wheel may have teeth at four times the pitch apart and the sprocket wheel
at two or three times. Or one wheel only may be constructed in this manner, the
other wheel having a complete set of teeth, without departing from this invention.
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:-
(1) In chain gearing for cycles and for mechanism generally, arranging the
teeth upon the chain and sprocket wheels so that they are two, three or more times
the pitch apart and all the links of the chain are consequently not in gear there-
with, substantially as described and for the purposes specified.
(2) In chain gearing for cycles and for mechanism generally, arranging the
teeth upon the chain and sprocket wheels so that they are two, three or more times
the pitch apart and all the links of the chain are consequently not in gear there-
with, the chain being also arranged so that each link is only in gear with the teeth
of the chain and sprocket wheels once in every second or third passage of the
chain round the wheels, substantially as described and for the purposes specified.
(3) In chain gearing for cycles and for mechanism generally the wheel A having
its teeth a arranged at three times the pitch apart, the wheel B having its teeth >>
arranged at twice the pitch apart and the chain C having a number of links which
is neither a multiple of two nor three, substantially as described and for the pur-
poses specified.
(4) Improvements in chain gearing for cycles and for mechanism generally
substantially as described and for the purposes specified.
Dated this 30th day of September 1898.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.