Improvements in or relating to Chain Gearing.
Year: 1898

page_text: Date of Application, 25th Jan., 1898--Accepted, 12th Mar., 1898
COMPLETE SPECIFICATION.
Improvements in or relating to Chain Gearing.
We, HARRY A. SCHRY, of Loreley, in the County of Baltimore, and State of
Maryland, and GEORGE KRUEGER and GEORGE WILD, both of Johnstown, in the
County of Cambria, and State of Pennsylvania, all in the United States of America,
Gentlemen, 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 drive chains and sprockets of the class which are especially
designed for use in bicycles or tricycles, but which may be used in any situation
where drive chains are applicable.
An object of this invention is to furnish a drive chain and sprocket which will
operate with the least possible friction, whereby there is less wear upon the mechanism
as well as the operator, and much less power is required.
A further object of this invention is to furnish a chain and sprocket in which the
wear incident to use is not concentrated at sharp points but is distributed över
smooth, somewhat extended, closely fitting curved surfaces, obviating all liability of
irregular wear or rattling of the parts.
With these objects in view, the invention consists in the improved construction,
arrangement and combination of parts hereinafter fully described and afterwards
specifically pointed out in the claims.
In the accompanying drawing-
Fig. 1 is a view of the improved chain and sprocket in side elevation, as practically
applied to a bicycle.
Fig. 2 is an enlarged detail view in side elevation, of one of the sprockets, with a
portion of a chain, the rest of the chain being broken away.
Fig. 3 is a central vertical sectional view through the devices illustrated in Figure 1,
except that the balls are shown in side elevation.
Fig. 4 is a perspective view of a sprocket wheel with the chain removed.
Fig. 5 is a detail perspective view showing a small section of chain.
Fig. 6 is a detail sectional view on a radial line, through a portion of the sprocket
and one of the balls of the chain and its sockets.
Fig. 7 is a detail perspective view showing the parts of which the chain is composed
detached from each other.
Fig. 8 is a fragmentary detail view in side elevation, showing a modified form of
sprocket and chain, and
Fig. 9 is a fragmentary detail view in perspective showing a small section of the
chain illustrated in Fig. 8.
Like letters of reference mark the same parts in all the figures of the
drawing.
Referring to the drawing by letters, A is a sprocket wheel, in this instance, see
Figure 1, shown as applied to a bicycle, although the invention, as before stated, is
applicable to any and all sprocket wheels and drive chains.

page_text: B is the chain, which encircles and connects the sprocket wheel with its fellow, to
transmit motion, in the usual manner, from one to the other.
The sprocket wheel A is provided with a hub C, which may be constructed in any
well known or approved form and while, in this instance, we show the wheel as being
of a single piece of metal, this is not obligatory, it being only requisite that it be pro-
vided with a suitable hub, a rim D, the construction of which will be described in
detail hereinafter, and a strong connection or support from the hub to the rim, which,
in the wheel we illustrate, consists of the portion E, of the solid piece of metal, of
which the wheel is made, although the rim and hub might be made of separate pieces,
one connected by a separate plate, or by spokes secured in any desired manner.
The rim D of the sprocket is provided with partially spherical sockets F, in its
periphery, separated by shallow curved notches G, and provided with waste escape
ducts or openings H, leading from the bottom of said sockets into openings I in the
body or plate of the sprocket, said openings also serving to lighten the weight of the
socket without detracting from its strength.
The chain B is composed of links, as is usual, each link consisting of two side
plates J, J connected together by pivotal rivets or screws K, and held at the proper
distance apart by thimbles, or short tubes L, around the pivots and between the
plates.
Centrally located in each plate, in its inner surface is formed a part M, of a spherical
socket, which part extends entirely through the plate, and when the two plates are
properly secured in place, these parts form portions of a single spherical socket, in
which is placed a bearing ball N, of steel or other suitable material, the sockets F, in
the periphery of the sprocket, forming parts of the same spherical sockets and receiv-
ing those portions of the balls which are between the link plates of the chain, when
the chain is on the wheel.
The separating thimbles or tubes L on the link pivots and between the link plates,
are fitted to rotate on said pivots and thus act as rollers, permitting the links to turn
freely on their pivots.
In Figures 8 and 9 we have shown a slightly modified form of chain and sprocket
wheel, in which the chain is formed of links of the same construction, but has the
ordinary connecting plate O, between the links, such construction necessitating the
widening of the curved notches G in the periphery of the socket.
It will be observed from the foregoing description that the balls carried by the
chains form teeth to enter the sockets in the wheels and they, while firmly held against
displacement or play in any direction, are perfectly free to turn in any and every
direction.
By reason of the provision of the waste escape ducts in the wheel, and the extension
of the sockets entirely through the link plates of the chain, any grease, dirt or other
foreign matter which may accumulate on the balls, or in the socket will be, as it
were, ground out through these openings.
The provision of the part sockets in the link plates extending entirely through the
plates is also advantageous in that it dispenses with considerable of the friction which
would be otherwise unavoidable, it being possible, with this construction, to make the
plates much thinner and lighter than it would be possible to make them were the
sockets not extended through them. The location of these openings will be best seen
by reference to Figure 6, which shows that while the balls are firmly held against
displacement by accident or otherwise, but a small portion of their surface is in actual
contact with other parts, thus dispensing with a large percentage of friction, wear,
and noise in operation.
The construction of chain and sprocket described gives absolute freedom to every
motion necessary to the proper transmission of power from one sprocket to another,
but at the same time absolutely prevents lost motion from slipping of parts on each
other and permits of the parts being made as light as possible with due regard to
strength. The link plates embrace the balls on both sides of their diameters, thus
assuring them against dropping out of the socket, which is substantially skeleton and
bringing the least possible surface contact between socket and ball. At the same

page_text: time the link plates overlap the sides of the sprocket immediately at the sockets and
prevent the balls jumping out of the wheel sockets should there be, at any time a
little lost motion due to slackness of the chain, or otherwise.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A drive chain link composed of two parallel link plates provided with suitable
end pivotal connections and separators, each plate having an opposite portion of a
spherical socket formed in its inner surface, and extended beyond said socket to
embrace or overlap the edges of the sprocket wheel when in use, a ball being seated in
said socket, substantially as set forth.
2. A drive chain link composed of two parallel link plates provided with suitable
end pivotal connections and separators, each plate having an opposite portion of a
spherical socket formed in its surface and extending through the plate, the plates
being extended beyond said sockets to embrace the overlapping edges of the sprocket
wheel when in use, a ball being seated in said socket, substantially as described.
3. The combination of a sprocket wheel provided with parts of ball sockets in its
rim, with a drive chain composed of links, each of which consists of two parallel plates
embracing the edge or rim of the sprocket wheel, each plate being provided with part
of a ball socket in its inner face, pivot pins connecting the links together, separators
to hold the link plates at a proper distance apart to cause the part sockets to register
with parts of one ball socket, and balls seated in the sockets of the links and engaging
in the rim sockets of the wheel, substantially as described.
1
BOULT & WADE,
Agents for the Applicants.