Improvements in Variable Speed Gear for Cycles and the like.
Year: 1898

page_text: Date of Application, 14th Jan., 1898—Accepted, 26th Mar., 1898
COM LEIM
Improvements in Variable Speed Gear for Cycles and the like.
I, JOSEF CERVA, of 40, Schlossergässchen, Reichenberg, Bohemia, in the Empire of
Austria, Butler, 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 arrangement of variable speed gear which has for its
object to enable the ratio of transfer in bicycles and the like to be altered whilst
running, thereby placing the rider in a position to travel under the most favorable
conditions of gear according to the actual conditions of the ground, as for instance a
lower gear when climbing a hill and a higher gear when descending.
The invention is shown in the accompanying drawings, in which,
Figure 1 is a side view of a bicycle fitted with this arrangement;
Figure 2, a section on an enlarged scale of the arrangement;
Figure 3, a bottom plan of Figure 2; and
Figure 4, a section of the arrangement on the line x x of Figure 3.
A tube bis mounted on the axle a on which the pedal cranks are keyed in the
ordinary way, which tube is firmly connected with the axle a and is revolubly
mounted in a second tube c on ball bearings. Two wedge grooves a¹ (Figures 2
and 3) are formed in the axle a in which grooves there are movably arranged
two wedges or keys e e¹ which are formed or provided near one end with a
disc d.
Two sprocket wheels f and F of different diameters are loosely mounted on the
axle a said sprocket wheels having their hubs provided with two grooves or key
ways F1 corresponding to the grooves a¹ on the axle a.
On the axle of the back wheel there are arranged of course two small sprocket
wheels 2, Figure 1.
The tube b encasing the axle a is provided with two slots &' in the end facing
the sprocket wheelf through which slots there extend the parts connecting the
wedges e e¹ with the disc d. The disc d is always pressed in one direction (in the
drawing to the right) by means of a spiral spring g connected with a ring h screwed
on the tube b, in which position the wedges or keys e e¹ engage in the grooves F¹
of the sprocket wheel F, Figure 2, so that this wheel must revolve with the axle a,
that is to say they must travel with the higher gear.
In order to enable the gear to be altered whilst running, a bar adjustable in
two loop pieces m m¹ is mounted on the under side of the bearing c, a small
wheel of vulcanite, wood or the like being revolubly mounted in the forked shaped
end of the said bar l.
If a levert mounted on the handle bar of the cycle be then pressed in the
direction shown by the arrow in Figure 1, the movement of the lever will be
conveyed to the aforesaid bar by means of links and levers 8 q¹q and an elbow
lever o which is pivoted on a pin p and connected with the bar at the point n
(Figure 3). By this means the bar and roller k are moved forwards (to the
left in the drawing in Figure 3) and the roller presses on the disc d and moves
the latter also forwards against the action of the spiral spring g. The wedges e e¹

page_text: moving with the disc d then quit the grooves F1 of the sprocket wheel F at
which moment both sprocket wheels are released from the axle a. The next
moment however the wedges e el engage with their other ends in the grooves f¹ of
the sprocket wheelf whereby the latter is firmly connected with the axle a and the
lower gear or ratio of transfer fz is established. When the condition of the ground 5
admits of a higher gear being employed, the lever t is released and the disc d is
thereby returned to its original position by the spiral spring g and the lever mechanism
is returned by means of the spring r connected with the pin p, that is to say the
former gear or ratio of transfer is again created.
Having now particularly described and ascertained the nature of my said 1
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. An arrangement for altering the gear of cycles whilst running, characterised by
wedges or keys (e e¹) being movably mounted in grooves or key ways (a') in the pedal
axle (a) and connected with a disc (d) by parts passing through slots (61) formed in 1
a tube (6) firmly connected with the axle, which wedges each time of their adjustment
whilst the machine is running (preferably from the handle bar of the cycle) are
adapted to firmly connect the axle (a) with one of two sprocket wheels (f and F)
loosely mounted on the ends of the axle (a) and connected with the back wheel of
'the cycle substantially as herein before set forth.
2
2. In the arrangement described for altering the gear of cycles whilst running,
the mechanism for adjusting or shifting the wedges or keys (e e¹) from the handle
bar, consisting of a bar (1) adjustably mounted on the support or bearing (c) of the
pedal axle and connected with one arm of an elbow lever (o) pivoting on a pin (p)
and connected with a lever (t) pivoted on the handle bar by means of links and 2
levers (q q¹ and s), which elbow lever on the lever of the handle bar being operated
adjusts or moves the disc (d) provided with the keys or wedges (e e¹) by means of a
roller (k) mounted in the forked end (¹) of the said bar (1) which overcomes the
resistance of a spring (g) and which after the release of the handle lever is returned
to its normal position by means of the springs (g and r) with the object of firmly 3
connecting with the axle (a) in the first case the one sprocket wheel (f) and in the
second case the other sprocket wheel (F) substantially as herein before described.
Dated this 13th day of January 1898.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.