Improvement in Sprocket Chains.
Year: 1896

page_text: Date of Application, 20th Feb., 1896-Accepted, 21st Mar., 1896
COMPLETE SPECIFICATION.
Improvement in Sprocket Chains.
We, BENJAMIN FRANKLYN SPARR of 3, Centre Street in the City of Newark,.
County of Essex and State of New Jersey, United States of America, Engineer,
and FREDERICK KNOPP PARTRIC, of 616 Pavonia Avenue, Jersey City, in the
County of Hudson and State of New Jersey, United States of America, Machinist,
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 an improvement in chains for connecting sprocket
wheels, commonly formed of a series of central links having their adjacent ends
connected together on opposite sides by the overlapping ends of lateral links.
pivotted thereto by pins having their ends flanged or rivetted outside of such
lateral links so as to secure such parts permanently together, whereby intermediate
spaces are formed between the extremities of the adjacent central links for the
penetration of the sprocket teeth.
The object of our present invention is to provide a sprocket chain of which the
pivotal pins shall be detachable to permit individual links to be removed from.
the chain for renewal when their effectiveness becomes impaired by wear, or in
order that links may be added or removed to lengthen or shorten the chain when it.
is required to change the sprocket wheels connected thereby for varying their
relative speeds, as is sometimes desired in bicycles and similar vehicles propelled by
power transmitted by cranks.
We attain this object by employing, in sprocket chains of ordinary construction,.
pivotal pins of a length slightly exceeding the combined width of the lapped ends
of the adjacent links, forming in the projecting ends of said pins lateral nicks or
grooves and applying to such nicked or grooved ends of each pair of adjacent pins
thin flat spring plates notched in one edge at each end to fit the same and overlying.
the outer or lateral members of the chain. In order to prevent the accidental
displacement of such flat spring plates, each is provided upon its inner face.
intermediate to the ends with a projection, formed by punching or other means
which is adapted to enter and engage with the countersunk outer end of a hole-
drilled transversely in the contiguous outer or lateral link of the chain.
In the accompanying drawing which illustrates our invention :-
Figure 1 is a view in side elevation of a short length of chain.
Figure 2 is a view in plan thereof.
Figure 3 is a view in side elevation of one of the flat springs, and
Figure 4 is a view in plan thereof.
Figure 5 is a view in side elevation of a short length of chain showing a.
modification of the spring plate, and
Figure 6 is a view in side elevation of the plate alone.
Figure 7 is a view showing the pivotal pin, and
Figures 8 and 9 are views showing modifications thereof.
Throughout the views similar parts are marked with like letters of reference.
The central link A and the lateral link B are of the ordinary construction and
present no novel features with the exception that in the outer face of the lateral
links intermediate to their ends is drilled or formed a small hole b countersunk on.
the outer side.
The pivotal pins C are of such a length that they project beyond the combined
width of the lapped ends of the adjacent links and in such projecting ends are cut.

page_text: or formed grooves c with which the slots d of thin flat spring plates D engage and
thus secure the parts together. On the inner face of each of the spring plates D
is formed a projection d' adapted to engage with the countersunk hole 6 in the
link B and thus provide against the accidental displacement of the spring plates.
Instead of having open ended slots in the both ends of the spring plate D as
shown by Figure 3 a key hole slot may be formed in one end as shown by Figures 5
and 6, and instead of having circular grooves in the ends of the pins C as shown by
Figure 7, lateral notches or slots may be formed as shown by Figure 9, and further
the pins C may be formed with a head or shoulder c' on one end, in which case
only the opposite end would require to be locked from withdrawal by the spring
plate D.
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
(1.) The improvement in sprocket chains, substantially as herein before described
and illustrated by the accompanying drawing.
(2.) A sprocket chain consisting essentially of central links A, of lateral links B,
of pivotal pins C having grooves or slots c at one or both ends, and of slotted spring
plates D adapted to engage with the grooves or slots c in the pins C, as and for the
purpose set forth.
(3.) A sprocket chain consisting essentially of central links A, of lateral links B
having small holes 6 intermediate to their ends, of pivotal pins C having grooves
or slots cat one or both ends, and of spring plates D having slots d adapted to
engage with the grooves or slots c in the pins C and projections d adapted to
engage with the holes & in the links B, as and for the purpose set forth.
Dated this 20th day of February 1896.
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Agent for the Applicants.