Improvements in Driving Chains for Velocipedes, and for other purposes.
Year: 1894

page_text: Date of Application, 19th Apr., 1894
Complete Specification Left, 18th Jan., 1895-Accepted, 9th Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in Driving Chains for Velocipedes, and for other
purposes.
1, JEAN BARDET, of 54 and 56 Avenue de la République, Paris, in the Republic
of France, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to a chain for transmitting motion, which is especially
applicable to velocipedes, but may also advantageously be employed for transmitting
rotary motion in machines in general.
The distinctive features of this chain are the mode of gearing the chain with the
pinions, and the particular form of the articulation, constituted by the straight
or curved knife edge of the link in the interior of a spring for connecting the
links.
This improved chain comprises links made in the form of a rectangle provided
with three rectangular apertures separated by cross pieces or bars connecting the
two long sides of the rectangle.
These links may also present other forms, for instance they may have lateral
recesses and two apertures, their short sides being rounded or formed with a knife
edge interiorly.
I also use links which are provided with lugs or projections at their four corners
and are hollowed out in their middle, their short sides being formed interiorly
with knife edges or simply rounded.
Instead of presenting lugs or projections at each of their corners the links may
have only two lateral lugs or projections arranged in the middle of the long sides,
or four lugs or projections arranged at equal distances from the corners.
Besides the kind of links before described my chain comprises spiral springs of
round or oval form which serve only to connect together the rectangular links.
These springs are made of wire of rectangular square or other suitable section and
their convolutions touch each other.
To form the chain I place the ends of two rectangular links close together and
put the spring over the side of these links by opening the first convolution and
then turning the spring so as to pass it entirely into the links.
In this way I connect the third and every following link to the last one, the
chain being finally closed by introducing the end links into the same ring.
The various forms of links hereinbefore described have for their object to
impart motion by means of these links themselves, while the springs serve only as
connecting parts and must never touch the teeth of the wheels or pinions geared
together by the chain.
During the movement of the chain round the pinions there will be no sliding of
the knife edges of the links upon the interior periphery of the springs, the tractive
force always tending to maintain the points of contact of two consecutive links at
the extremities of a diameter of the spring which connects them.
The pinions may engage with the chain links either interiorly or exteriorly. In
the latter case the pinions are double with a tooth on each side for the pitch except
in the case of chain links having four lugs or projections arranged at equal distances
from the corners as hereinbefore set forth, for which the pinions have two teeth on
each side for each chain nitch

page_text: Of great importance is the curved profile which I give interiorly to the short
sides of the links instead of forming them with knife edges. This curved profile
is more especially designed for links connected by round springs and for this
purpose the curvature in question has a radius equal to the interior radius of the
spring. The exterior plane of the link practically passes through the axis of the
spring or slightly above the same when the chain is stretched in a straight line;
moreover the corner formed by the curvature and the exterior face of the link is
slightly rounded in order to obviate rapid wear of this corner. In the movement
of the chain round. the pinions only one point of the curved part of the link
beats upon the spring and constitutes the edge upon which the oscillation takes
place.
This arrangement which gives to the parts of the chain a maximum surface of
contact has for its object to reduce to a minimum the flattening of the parts
in consequence of excessive strains; and if despite this precaution a flattening
should take place the curved surface and also the pitch of the chain remain
intact.
With links shaped interiorly to a definite curvature instead of being formed with
a knife edge, the movement of the chain round the pinion can take place only in
one direction without sliding and with articulation of the link.
On each side of the teeth are preferably provided, upon the pinions or gear
wheels, faces upon which bear the internal faces of the long sides of the links during
the movement of the latter.
Dated this 19th day of Auril 1894
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Driving Chains for Velocipedes, and for other
purposes.
I, JEAN BARDET, of 54 and 56 Avenue de la République, Paris, in the Republic
of France, Civil 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 :-
My invention relates to a chain for transmitting motion, which is especially
applicable to velocipedes, but may also advantageously be employed for transmitting
rotary motion in machines in general.
The distinctive features of this chain are the mode of gearing the chain with the
pinions, and the particular form of the articulation, coustituted by the straight
or curved knife edge of the link in the interior of a spring for connecting the
links.
In the accompanying drawings
Figure 1 is a sectional elevation of a chain mounted upon a pinion.
Figure 2 is a plan of Figure 1.
Figures 3 and 4 are respectively an elevation and plan of a modification of my
chain likewise mounted upon a pinion.
Figures 5 to 12 are details.
Figures 13 and 14 are respectively
modification.
a sectional elevation and a plan of a
This improved chain comprises links a made in the form of a rectangle provided
with three rectangular apertures a', a³, a³ separated by cross pieces or bars bb
connecting the two long sides of the rectangle (Figures 1 to 4).
These links may also be made of other forms. Figures 5 and 6 represent a link

page_text: having lateral recesses c c and two apertures c¹ c¹ their short sides being rounded or
formed with a knife eilge interiorly as shown in Figure 6.
Figures 7 and 8 represent links which are provided with lugs or projections d d
at their four corners and are hollowed out in their middle, their short sides being
formed interiorly with knife edges or simply rounded.
Instead of providing lugs or projections at each of their corners the links may
have only two lateral lugs or projections d' d', as shown in Figures 9 and 10
arranged at about the middle of the long sides or the link may have four lugs
or projections dd, as in Figures 11 and 12 arranged at equal distances from the
corners.
Besides the links hereinbefore described my chain comprises spiral springs e of
round form as shown in Figures 1 and 2, or of oval form as in Figures 3 and 4
which serve only to connect together the rectangular links. These springs e e are
made of wire of rectangular, square or other suitable section the convolutions of
which touch each other.
To form the chain I place the ends of two rectangular links close together and
put the spring e over the side of these links by opening the first convolution and
then turning the spring so as to pass it entirely into the links in a manner similar
to that in which a key is introduced into a split ring.
In this way I connect the third and every following link to the last one, the
chain being finally closed by introducing the two end links into the same ring.
The various forms of links hereinbefore described have for their object to impart
motion by means of these links themselves, while the springs e, e serve only as
connecting parts and must never touch the teeth of the wheels or pinions geared
together by the chain.
During the movement of the chain round the pinions there will be no sliding of
the knife edges of the links upon the interior periphery of the springs, the tractive
force always tending to maintain the points of contact of two consecutive links.
at the extremities of a diameter of the spring which connects them. (Figures 1
and 2.)
The pinions gearing with the links represented in Figures 5 to 11 are constructed or
the same principle as those of Figures 1 to 4. It should be observed however that.
in the foriner links, the gearing being exterior, the pinions are double, with a tooth
on each side for the pitch except in the case of chain links having four lugs or
projections arranged at equal distances from the corners as shown in Figure 11 for
which the pinions have two teeth on each side for each chain pitch.
The curved profile which I give to the short sides of the links instead of forming
them with knife edges is of great importance. This curved profile is more
especially designed for links connected by round springs and for this purpose the
curvature in question has a radius equal to the interior radius of the spring c..
The exterior plane of the link (Figure 1) practically passes through the axis of
the spring e or slightly above the same when the chain is stretched in a straight line ;.
moveover the corners m, n formed by the curvature and the exterior faces of the link
is slightly rounded in order to obviate rapid wear of this corner. In the movement
of the chain round the pinions only one point m of the curved part of the link
bears upon the spring and constitutes the edge upon which the oscillation takes
place.
This arrangement which gives to the parts of the chain a maximum surface of
contact has for its object to reduce to a minimum the flattening of the parts.
in consequence of excessive strains, and if despite this precaution a flattening
should take place the curved surface m n and also the pitch of the chain remain.
intact.
With links shaped interiorly to a definite curvature instead of being formed with
a knife edge, the movement of the chain round the pinion can take place only in
one direction without sliding and with articulation of the link, indicated in
Figure 1.
On each side of the teeth are preferably provided, upon the pinions or gear

page_text: wheels, faces ƒ ƒ upon which bear the internal faces of the long sides of the links
during the movement of the latter.
As shown in Figures 13 and 14 I may unite the adjoining links a a by means of
two springs e e¹ separated by longitudinal bars o o¹. This arrangement of the
chain with a double spring is designed for mechanical applications such as for the
transmission of motive power in automobile carriages and the like, that is to say,
where the power to be transmitted is comparatively great.
The chain may also be made with several links arranged laterally.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what 1
claim is :-
1st. An endless chain for transmitting motion, composed of links of rectangular
form and rings or links forming spiral springs of oval or circular shape the
convolutions of which touch each other and which are wound round the short
sides of the links having the form of a rounded knife edge for connecting two
consecutive links, the rectangular links being provided with internal or external
appendices by which the said links may bear flat upon corresponding flat parts of
the pinion or wheel which the chain connects substantially as hereinbefore
described and represented in the drawings.
2nd. An endless chain for transmitting power composed of links of rectangular
form connected with each other two and two by two rings forming spiral springs,
separated by longitudinal bars, substantially as hereinbefore described and
represented in the drawings..
1905
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.