Improvements in Driving Mechanism for Velocipedes and other Vehicles with Variable Gear.
Year: 1897

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Date of Application (in United Kingdom), 10th Mar., 1897
Complete Specification Left, 10th Mar., 1897-Accepted, 1st May, 1897
COMPLETE SPECIFICATION.
Improvements in Driving Mechanism for Velocipedes and other
Vehicles with Variable Gear.
1, 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 :-
The driving mechanism consists of oscillating treadles, chains or ropes and
ratchet couplings, the latter, which act upon the shaft of the driving wheel directly
or indirectly, connected to the treadles by means of the chains or ropes. The
novelty consists therein, that the fulcrum of the treadle is movable, whereby the
angle between the chain and the treadle and thus the gear becomes variable.
The fulcrum of the treadle can be situated below or above the shaft of the disc, on
to which the chain is alternately wound and unwound. The former case is
shown in Fig. 1 and the latter case in Fig. 2 of the accompanying drawing.
The treadle A is fixed to an arm B, descending from the frame and along which
the fulcrum of the treadle can be moved. The chain or rope C is fixed to the
other end of the treadle and runs directly to the disc D, on to which it is alternately
wound and unwound. If the fulcrum of the treadle is moved upwards, the angle
between the chain and the treadle decreases and the tension on the chain increases
and vice versa.
If the parallelogram of forces is drawn and the angle is a; the
tension is equal to a, but if the angle is for instance a' which is less than a and
which is obtained, when the treadle is moved to N, the greater tension a' is
obtained. The treadle may be mounted on the arm B, which is somewhat bent, in
different manners, for instance by means of a sliding piece, movable along the arm
and to which the treadle shaft is fixed, or thereby that the arm is provided with a
longitudinal slit, through which the treadle shaft passes. The readjustment can
take place by means of a thin bar E, connected to said sliding piece or to the shaft
and ascending along the arın B and the stay F, this bar being above connected to
a bell crank lever G or the like serving to move the same. Each of the treadles
which are situated on each side of the wheel H, is, of course, fixed to its arm B
with corresponding bars E. The bars E are above connected by the bell crank
lever G. The treadles are connected one with another by the chain K, running
over a disc L and by means of which the one treadle is pulled upwards by
the other.
If the fulcrum of the treadle is transferred above the disc D (Fig. 2), it may be
fixed directly to the stay F, which preferably is somewhat curved, in order that the
treadle, when moved along the stay, may not move in the longitudinal direction of

page_text: the velocipede. However the manner of mounting the treadle shaft, as well as the
device for readjusting the treadle, may be similar to those, described above. When
moving upwards, the treadle tends to stretch the chain and must therefore be
actuated by the chain K and the other treadle which is depressed. If the fulcrum
of the treadle is moved downwards, the angle between the treadle and the chain is
decreased, but if the fulcrum is moved upwards, said angle is increased, whereby
the gear is increased and decreased respectively. The forces a 2 a 3 represent the
different tensions on the chain at two different positions M and N of the treadle.
It may also be supposed that the two constructions (Figs. 1 and 2), are put
together in a single one, the stay F (Fig. 2) being prolonged downwards for
forming an arm B, so that the treadle can be moved along the whole bow between
the extreme positions, shown in Figs. 1 and 2.
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, chains or ropes and ratchet couplings, acting on the driving
wheel and connected directly or indirectly to the treadles, by means of the chains
or ropes, the arrangement that the fulcrum of the treadle is movable, so that it can
be placed at a greater or shorter distance from the centre of the disc, on which the
chain is
1 with the view that the angle between the
treadle and the chain and the the might be id
2. In the arrangement stated in Claim 1 the arrangement of
(B)
descending from the frame and to which the treadle is fixed in such a mannor, that
it can be moved along the same.
3. Velocipedes and other vehicles, provided with the arrangement stated in
Claim 1, and which have the treadle movably mounted on that stay of the frame,
which passes between the centre of the driving wheel and the upper part of the
frame, in such a manner that the treadle can be moved along said stay.
Dated this 10th day of March 1897.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, London, Agents to Applicant.