Improvements in Driving Mechanisms with Variable Gear, adapted for Velocipedes and other Vehicles.
Year: 1897

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by
the decision of the Chief Examiner. Of the 9th day of April 1898.
Improvements in Driving Mechanisms with Variable Gear, adapted
for Velocipedes and other Vehicles.
I, AXEL FREDRIK ABRAHAMSON ROXENDORFF, of 73, Avenue du Bois de
Boulogne, Paris, in the Republic of France, 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: -
This invention relates to improvements in such velocipedes and other vehicles,
the driving mechanism of which consists of oscillating treadles, to which are fixed
chains or ropes, running from ratchet couplings, which act upon the shaft of the
driving wheel. Hitherto the chain used to run directly to the treadle, which has
necessitated the placing of the treadle shaft at a rather great distance from the
centre of the ratchet coupling, which centre is, if possible, arranged to coincide
with the centre of the driving wheel, the coupling being mounted directly upon the
shaft of said wheel. On the contrary, according to this invention the centre of
the treadle coincides with or is situated close to the centre of the coupling, the
chain being guided angularly over a roller down to the treadle. Thereby the
velocipede obtains a more suitable form, besides which the gear can be made fit
for regulation by making the said roller movable.
On the accompanying drawing,
Fig. 1, shows a side elevation of a velocipede of the kind in question.
Fig. 2 shows the treadle in different positions,
Fig. 3 shows a modification and
Fig. 4 shows a cross section of some details.
The treadle A is pivotally mounted on the shaft C of the driving wheel B and
near its fore end it is connected to the chain D, passing over the disc E on its way
to the disc F which belongs to the ratchet coupling and onto which the chain is
wound and unwound in the usual manner. The disc E is mounted on a sliding
piece, consisting of a tube G which can slide within the stay H of the frame, this
stay being slotted on its lower side so as to permit the bracket of the roller and the

page_text: •
chain to pass out from the interior of the stay. As shown in Fig. 1, the chain runs
from the roller E to the disc F through the stay H. The tube. Gis caused to
slide in different manners, for instance by means of a lever I, connected to the
bar K which is fixed to the tube and situated within the stay H. For elucidating
the effect of the displacement of the disc there is a parallelogram of forces for
two different positions of the disc (see Fig. 1). If the disc is at A' and if
a represents the force, with which the treadle is pressed downwards, the tension in
the chain becomes equal to the force b. If the disc is moved to A2, the tension
in the chain becomes equal to the force 61, which is considerably greater than the
force b as clearly shown by the figure. In the former case the propelling force 1
becomes small, but the speed of the vehicle becomes great, and in the latter case
the propelling force becomes great, but the speed less. The described arrangement
may easily be modified and the same result yet be obtained. For instance instead
of mounting the disc on the stay H it may be mounted on the more upright stay H 1,
so that it can be movable along the same. The fixing point of the chain on the
treadle may also be movable along the treadle, for instance by means of a piece,
sliding along the treadle and to which the chain is connected at the same time as
the disc is movable. If now the disc is moved in one direction and the above
mentioned fixing point in the other, a rapid change of the gear is obtained without
considerably changing the angle, within which the treadle oscillates.
The or may plen he mounted on the trendle and the cuì of the chain
movably fixed to the stay H. This is shown in Fig. 3. The chain, running trom
the di-c F passes under the roller mounted on the treadle, and upwards to the
stay H, to which it is movably fixed, for instance by means of such a sliding piece G,
as described above. If the fixing point of the chain is at A¹ the tension on the
chain becomes equal to b, but if said point is moved to A2 the tension on the chain
increases and becomes equal to 6. By using a hollow treadle or by providing the
treadle with a longitudinal tube the chain can run through the treadle or the tube
to the disc F, thus being covered the greatest part of its length.
Another advantage of this invention consists therein that the chain (Fig. 1)
occupies the position producing the greatest tension on the same, when the leg of
the driver is most bent, thus exerting the least force for depressing the treadle.
This is shown in Fig. 2. When the treadle is lifted (position A 3), the chain forms
the small angled with the same, whereby the great tension el is produced on the
chain, but when the treadle is depressed (position A4), the chain and the treadle
form a greater angle d' and the tension c2 on the chain becomes less. When the
treadle is in the depressed position, however, the driver can exert a great pressure
on the treadle, as his leg is then stretched.
Fig. 2 also shows the employment of a link g¹ fixed to the stay H₁ and carrying
the roller E. For displacing the roller the same lever I and bar K, as shown in
Fig. 1, may be employed. For lifting the treadle, a spring, a chain running
over a roller i and connecting the treadles, or another known arrangement may be
employed. Each treadle is provided with two projections m and n, situated at
different distances from the centre of the treadle. By placing the foot on the one
or the other of these projections, a longer or shorter leverage can be obtained. In
the drawing the treadle is carried by the shaft C of the driving wheel, but as
already mentioned, it may evidently be mounted on a special pivot, situated at a
greater or smaller distance from the said shaft. still using the described system of
a driving chain or rope, running over a movable roller. If the roller is large, it
may have the shape of a sector, about which the chain runs to the treadle.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In velocipedes and other vehicles, the driving mechanism of which consists
of oscillating treadles, to which are fixed chains or ropes, running from ratchet
couplings, which actuate the shaft of the driving wheel, and wherein the chair

page_text: [] improvements In Living mechanisms wiin variable Gear.
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or rope (D) does not run directly to the treadle, but at an angle over a roller (E)
to the treadle the mounting of said roller movably so that the angle between the
chain and the treadle can be increased or decreased by displacing the roller, with
the view that the gear may be regulated.
2. The modification of the arrangement, whereby the end fastening of the chain
is not situated on the treadle but in a point, situated above the treadle on the frame,
while the roller round which the chain or rope runs to its coupling disc is mounted
on the treadle, the first mentioned fixing or bearing point of the chain being
movable in the longitudinal direction of the vehicle, so that the angle between the
chaia and the treadle can be increased or decreased in order to regulate the gear.
3 In velocipedes and other vehicles the arrangement that the fixing point of
the driving chain on the treadle is movable along the treadle at the same time as
the chain runs over such an adjustable roller (E) as stated in Claim 1 with the
view rapidly to increase or decrease the gear by moving the roller backwards and
the above mentioned fixing point forwards and vice versa.
HERBERT HADDAN
Co.,
18, Buckingham Street, Strand, London, Agents to Applicant.