Improvements in Variable Speed Gear for Velocipedes.
Year: 1896

page_text: Date of Application, 10th June, 1896
Complete Specification Left. 14th Sept., 1896-Accepted, 7th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements in Variable Speed Gear for Velocipedes.
I, JEAN dit JULES TRUCHOT of 73. Rue des Moines, Paris, France, Artisan, do
hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in variable speed gear for velocipedes
whereby to enable the steepest hills to be climbed without fatigue while on a level
or a down grade very high speed may be attained with ease, hence economy of
power and increase of speed. The change from one speed to the other is effected
by shifting the axial position of the ball bearing casing of the pedal crank axle
and the invention consists in the combination of a crank axle mounted in a ball
bearing casing which is externally eccentric to the crank axle and is movable
circularly in a stationary shell having an eccentric flange formning a ball bearing
path upon which the sprocket wheel revolves the sprocket wheel being driven at
two different speeds according as it is connected directly with the pedal cranks or
driven through toothed gearing from the crank axle, the toothed gear being thrown
in and out of engagement by shifting the axial position of the crank axle ball
bearing box.
The invention is illustrated by way of example in the accompanying drawings
wherein
Figure 1 is an elevation of the change gear at the sprocket wheel side.
Figure 2 an axial section and
Figure 3 is a view at the opposite side to Figure 1.
Figure 4 represents a longitudinal section and Figure 5 a part sectional end view
of a modified arrangement of the apparatus.
Figure 6 is an inside face view of the pedal crank shewing internal toothed
wheel.
The same letters of reference denote like parts in all the figures.
The apparatus essentially comprises the ball bearing casing a in which is mounted
the axle carrying the pedal cranks c d. The ball bearing a is externally eccentric
to the crank axle 6 and is circularly adjustable within a stationary shell e being
retained by a spring latch f engaged in slots g in the shell e corresponding to the
two positions which the crauk axle & should occupy. The spring latch fis disengaged
by means of a lever i pivoted thereto and taking a fulcrum on one or other of two
studs upon the ball bearing casing d so as to thereby turn the latter in the
one or other direction for the purpose of shifting the position of the pedal crank
axle the locking of it in position for high or low speed taking place merely by
the release of the lever i. Upon an eccentric flange of the shell e forming a ball
hearing surface revolves a ring k carrying the chain sprocket wheel said ring
having an internal circle of teeth with which gears a pinion n keyed on the crank
axle & when the latter is shifted to its other position. The direct connection of
the crank c with the ring k is effected by means of a self-engaging spring bolt o
mounted in the crank arm and engaging in a recess p. The lever is actuated
through any suitable means and in high speed the crank drives the ring k by
direct engagement therewith of bolt o the axle b and ring k revolving about a
common axis, the change of speed being effected by shifting the ball bearing box
and crank axle 6 so as to throw the pinion n into engagement with the internal
gear wheel m on ring the extent of movement being such that the bolt o is

page_text: disengaged from the ring k before pinion n engages with the teeth of m. When
changing from one speed to the other the pedals may remain stationary but without
raising the feet off thein.
Figures 45 and 6 shew an arrangement in which the ring k carries the pinion m'
which gears when the axial position of the axle b is shifted, with the internal wheel n¹
on the disc-shaped head of pedal crank c. In this case at low speed the crank c
engages the sprocket wheel directly by bolt o the change to a high speed being
effected by shifting the axial position of the ball bearing box a so as to throw the
internal ring n into gear with the pinion m¹, the bolt o quitting ring k before the
engagement of n' with m¹ is effected.
Dated this 10th day of June 1896.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Variable Speed Gear for Velocipedes.
I, JEAN dit JULES TRUCHOT of 73 Rue des Moines, Paris, France, Artisan, 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 improved two-speed gear for velocipedes whereby to
enable steep hills to be easily climbed and high speed to be attained on a level road.
The change from one speed to the other is effected by shifting the axial position
of the ball bearing casing of the crank axle and the invention consists in the
combination of a crank axle mounted in a ball bearing casing which is externally
eccentric to the crank axle and is movable circularly in a stationary shell having an
eccentric flange forming a ball bearing path upon which the sprocket wheel revolves
the sprocket wheel revolving at different speeds according as it is connected directly
with the pedal cranks or is driven through toothed gearing from the crank axle,
the toothed gear being thrown in and out of engagement by shifting the axial
position of the crank axle by partially rotating its eccentric ball bearing box.
The invention is illustrated by way of example in the accompanying drawings and
also in Sheet 2 of the drawings left with the l'rovisional Specification wherein
Figure 1 is an elevation of the change gear at the sprocket wheel side.
Figure 2 an axial section and
Figure 3 is a view at the opposite side to Figure 1.
Figure 4 represents a longitudinal section and Figure 5 a part sectional end view
of a modified arrangement of the apparatus.
Figure 6 is an inside face view of the pedal crank shewing internal toothed
wheel.
The same letters of reference denote like parts in all the figures.
The apparatus essentially comprises the ball bearing casing a in which is mounted the
axle 6 of the pedal cranks c d. The ball bearing casing a is externally eccentric to
the crank axle 6 and is circularly adjustable within a stationary shell e fixed in
or forming part of the bottom bracket of the machine frame, the casing a being
retained in the one or other position by a locking spring bolt f which engages in
one or other of two slots g g in the shell e which respectively correspond to the
two positions which the crank axle b should occupy. The spring bolt fis disengaged
by means of a lever i pivoted thereto and taking a fulcrum against one or other
of two studs fixed to the end of the casing a so as to thereby first disengage the
locking bolt from the slot g in which it is engaged and then turn the eccentric
casing a within the shell e through an arc of a circle equal to the space between the

page_text: The-
two stops g g' for the purpose of shifting the axial position of the crank axle.
lever i is operated through a connecting rod by a hand lever within convenient reach
of the rider and the locking of the casing a in position for high or low speed takes
place by the release of the lever i allowing the bolt f to engage in the notch q
Upon an eccentric flange of the shell e forming a ball bearing path revolves a ring
to which is fixed the chain sprocket wheel said ring having an in ernal circle of
teeth m with which a pinion n keyed on the crank axle gears when the axial
position of the crank axle is shifted to its other position so that the bolt f is engaged
in the slot g', the eccentricity of the ball bearing path of the ring k with regard to the
shell e being such that it is concentric with the crank shaft when the latter is
concentric with the internal ring of teeth m. The direct connection of the crank c
with the ring k is effected by means of a self-engaging spring bolt o mounted in the
crank arm and engaging in one of a circle of recesses p when the pinion n is out of
gear and occupies the concentric position shewn within the internal ring m.
In high
speed the crank therefore drives the ring k by this direct engagement therewith of
bolt o the axle 6 and ring k revolving about a common axis and the change of speed!
is effected by shifting the axial position of the crank axle b so as to throw the pinion n.
into engagement with the internal gear wheel m. The effect of this movement is to-
first cause the bevelled end of the bolt o to slide up the correspondingly bevelled end
of the notch pin which it is engaged and so cause the bolt o to be disengaged from the-
ring before the pinion n engages with the teeth of m. In this disengaged position the
end of the bolt o bears against the flat surface of the ring k and its orbit of revolution
is then eccentric to the circle of notches p; the bolt a will then slide over without
becoming engaged in them. As soon however as the crank shaft is returned to.
the axial position shewn, by the reverse action of the lever i the bolu o becomes.
re-engaged and drives direct for high speed. When changing from one speed
to the other the pedals may remain stationary but without raising the feet off
them.
Figures 45 and 6 shew an arrangement in which the ring carries the pinion m¹
with which gears the internal wheel n' on the disc-shaped head of pedal crank c
when the axial position of the axle band consequently of the internal wheel n¹ is.
shifted as shewn in dot-and-dash lines in Figure 5. At low speed the crank c
engages the sprocket wheel directly by bolt o, the change to a high speed being
effected by shifting the axial position of the crank shaft b so as to throw the internal
ring n' into gear with the pinion m', the bolt o being disengaged from ring k before.
the engagement of n' with m' is effected.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The herein described arrangements of two-speed gear for cycles wherein the
change of speed is effected by shifting the axial position of the crank axle, the
parts being constructed, combined, and arranged to operate substantially as herein.
described and illustrated in the respective figures of the drawings.
2. In a two-speed gear for cycles wherein the change of speed is effected by
shifting the axial position of the crank axle and wherein the crank axle is mounted
to rotate in a ball bearing casing which is externally eccentric to the crank axle
and is mounted to turn through an arc within a stationary shell, the ring carrying
the sprocket wheel mounted to revolve upon a ball bearing path eccentric to the
stationary shell, said ring having an internal ring of teeth with which a pinion on
the crank shaft may be caused to gear and having a circle of notches with which a
self-engaging and self-disengaging bolt on the crank may engage when the pinion
is out of gear with the internal ring substantially as specified.
3. The combination, with the herein described two-speed gear constructed to
operate as specified in Claim 2, of the herein described locking bolt for fixing the
gear in the one or other position and of the means whereby it may be disengaged

page_text: and the partial rotation of the eccentric bearing of the crank axle effected sub-
stantially as specified.
4. The combination, with the herein described two-speed gear, of the spring bolt
on the pedal crank and the circle of notches in the sprocket wheel, the bolt being
self-engaging and disengaging by the shifting of the axial position of the crank shaft
substantially as specified.
Dated this 31st day of August 1896.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents..