Improved Driving Gear for Velocipedes and the like, and for Vehicles to be used on Land or Water.
Year: 1898

page_text: Date of Application, 19th Sept., 1898-Accepted, 3rd Dec., 1898
COMPLETE SPECIFICATION.
Improved Driving Gear for Velocipedes and the like, and for
Vehicles to be used on Land or Water.
I, WILHELM BACKES, of 48, Seelenpfad, Remagen-on-the-Rhine, Germany,
Merchant, 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 improved driving gear intended principally for
velocipedes but suitable for use in all cases in which a vehicle to be used on land or
water is to be propelled by human power. The peculiar characteristic of the
improved gear is that, within certain limits, the vehicle can be driven with a
variable power without requiring the operator to dismount whilst propelling the
vehicle to alter the gear. Only when the power is to be materially altered, will it
be found desirable to alter the adjustment, this, however, can be easily effected
even during a run.
The invention is illustrated on the accompanying drawings, in which,
Fig. 1 is a side elevation of a vehicle fitted with the improved gear.
Fig. 2 is a sectional detail view through the gear properly so called.
Fig. 3 is a horizontal section corresponding with Fig. 2.
Fig. 4 is a modification of the gear; and
Fig. 5 is a diagram serving for the theoretical explanation of the operation of the
arrangement.
In the drawings a, b, indicate an angle lever, of which the arm, a, serves as the
crank and carries a pedal, c, of the usual kind. One such angle lever is provided on
each side of the vehicle. The pedal levers are mounted on fixed pins, d, (Fig. 3) and
are free to rotate in the direction of the arrow, e, (Fig. 1) when operated by the
foot. The free ends of the arms, b, of the pedal levers are jointed, so as to transmit
power to cords, f, which pass over rollers, g, one of which is provided on each side
of the vehicle, corresponding to the pedal levers; the two rollers being connected
with the hub, h, of the rear wheel, i, by any suitable clutch-gearing.
In Figs. 2, and 3, is shown a ball clutch arrangement which is suitable for such
purpose. A spring, k, has oue end firmly attached to the non-rotating rear
spindle, l, at m, (Fig. 3) its other end being attached by a pin at m¹, to the
roller, g, so as to transmit power. This connection constantly pulls the roller, g, in
the direction indicated by the arrow, n, (Fig. 2) so that the cord, f, always remains
In lieu of the spring, k, a weight or the like may be used for automatically
winding up the cord, f.
taut.
From the foregoing, and from Figs. 1, and 2, it is clear that when the pedal
levers, a, b, are left to themselves, the pull of the cords, f, passes through the
geometrical axis of the pin, d. When the velocipede or vehicle is at rest and
power is exerted on one of the pedals, c, the arm, b, of the pedal which is being
depressed will move upwards, and as the main line of motion of the point of
connection, o, of the arm, b and cord, f, at the commencement of the motion is at
right angles to the pull of the rope or cord, the initial movement of the cord (in the
direction of its own length) will be infinitesimally small, and theoretically, its

page_text: driving power, infinitely large; consequently, the wheel will be pushed from its
position of rest without shock and with great force. The further the lever arm, b,
moves upwards, the less obtuse will be the angle formed by the cord, f, and the
arm, b, it being 180° at first, and, the power remaining uniform, at the point, o, the
pull in the cord, f, will decrease, and when b, has rotated so far as to be at right
angles to the cord, f, the tension in the latter is exactly equal to the tangential
power acting in point o.
The diagram Fig. 5, illustrates the diminution of power in the cord corresponding
to the advance in movement of the lever arm, b. When the arm, b, is at right
angles to the cord, f, (Fig. 5) the cord will be unrolled with the velocity of the
point, o. Moreover, as in the original position of the lever, b, the latter moves in a
direction at right angles to the pull of the cord, f, the unrolling of the cord is also
equal to zero. It follows that the velocity at which the cord is unrolled during the
progress of the lever from the zero-position to that in which the angle enclosed
between, b, and f, is 90°, must constantly increase, which, in other words, means
that, the pressure on the pedal retaining the same, and the velocity of the
pedal during the down-stroke being also assumed to remain the same, the latter
will, nevertheless, unroll the cord, f, from its roller, g, with a constantly increasing
velocity, so that the ball clutch, g, h, will also drive the wheel, i, with increasing
velocity.
This effect becomes particularly noticeable in starting. Whilst running at full
speed on a level road, the speed of the wheel varies within very narrow limits only,
so that the advantage of gradual increase in velocity does not become so apparent.
When travelling over a very undulating road or on steep ascents, the advantage of
this driving gear becomes more noticeable.
With reference to Fig. 5, it has already been mentioned that the power acting in
the cord during the upward motion of the lever-arm, b, varies considerably, viz.:
notably diminishes. During that part of the stroke of the lever during which it
makes an angle of not much less than 180° with the cord, the driving power is
much greater than that exerted at right angles to the lever, the latter must be
taken as the constant power, whilst, when the angle between f, and b, approaches
more nearly to 90°, the power exerted in the cord differs but little from that
assumed to be the constant power, dependent on the pressure on the pedal, and, in
Fig. 5, taken to be 50 kilos., by way of example. From this, it follows, however,
that the mean power in the cord, when the lever departs only 25° from the
extended position shown on Fig. 2, will be materially greater than when, by further
depression, the lever is swung through say 50°. It further follows that, when a
steep rise in the road is to be overcome, the pedals are to be depressed rapidly, but
through a small angle only, so that, in this manner, the progress may be at a less
rate of speed but with greater power, whilst, on a horizontal level road, the utmost
stroke is to be given to the pedal to correspond with the very much diminished
resistance of the wheel, so as to increase the rapidity with which the cord is
unwound. The driving gear herein described has, it will thus be seen, the very
important characteristic referred to in the beginning of this description, namely,
that with rapid pedalling and a short stroke great resistances can be overcome, for
instance, heavy gradients, whilst slower pedalling with a greater stroke corre-
sponding to the lesser resistance of a good level road will permit very rapid travel
without requiring the rider to leave the saddle.
In order not to be dependent on the pedalling movement alone, when it is desired
either to overcome exceptionally steep gradients or to attain exceptionally high
speed on level roads, it may prove desirable to vary the length of the lever, b.
Figs. 1, 2, 3, show a construction that will admit of this. In this construction, the
lever, b, is made hollow, and within it is fitted a rod, 61, capable of being fixed in
position by a set screw, p, Fig. 2. Now is 6', is pulled out beyond what is required
to allow of its being, as it were, solid with the lever, b, the path through which the
cord, f, passes, for a given stroke of the pedal, c, is considerably increased, and
correspondingly the speed also. The particularly high gear of course pre-supposes

page_text: a very good road, or a very level track. If 61, is pushed inward in b, then the
unrolling of the cord for a given stroke of the pedal will correspondingly diminish,
and so the travel of the wheel per stroke of the pedal will be proportionately less.
To this much decreased velocity corresponds highly increased traction in the cord, f,
so that very uneven roads or very steep gradients may be overcome without undue
exertion.
Fig. 4, represents a modification of the driving gear also capable of imparting
high speed to the wheel. On the free end of the lever, b, is mounted a roller, q,
over which the cord passes, thence going over a fixed roller on to the rear fork,
and then over another roller, t, on the lever, b. From t, the cord passes back to a
point of attachment, ut, on the fork, r. The roller, t, may also be omitted, and the
point of attachment, u, may be provided directly on the lever, b. On the other
hand, a further roller may be provided at u, and the point of attachment be pro-
vided on b next to t. With this construction, when the pedal, c, is depressed, the
rollers, q, t, s, will act after the manner of a pulley-block, that is to say, a small
movement of the lever, b, will unwind several times as much of the cord, so that
though the pedals are depressed very slowly, the wheel will travel very fast. The
levers, a, b, on each side of the machine can be independent of one another, as the
spring k, Fig. 3, will always rewind the unwound cord so soon as the pressure on
the pedal ceases.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is :-
1. A driving gear for vehicles and machines driven by human power, characterized
by a lever, b, whose free end is connected with a device for transmitting motion to
the wheel, i, by means of a clutch gearing, h, g, or the like, which lever, in its
position of rest is in a straight or approximately straight line passing through the
point of rotation d, with the cord, f, or its equivalent, and, as soon as caused to
swing by the rider, causes the pulling or transmitting device, f, to be unrolled, the
latter being by a spring, weight or the like automatically wound up again when the
power ceases to actuate the lever, b, as set forth.
2. A driving mechanism such as referred to in Claim 1, characterized by having
the point of engagement between the pulling or transmitting device, f, and the
lever, b, adjustable, by lengthening or shortening the latter, for the purpose of
materially altering the speed at which the machine can travel, as set forth.
3. A driving gear such as referred to in Claim 1, characterized by having one or
more loose rollers provided on the lever, b, as well as on a fixed part of the machine
over which rollers the pulling device, f, passes in the manner of a pulley-block for
the purpose of varying the transmission of power.
Dated this 17th day of September 1898.
DAY, DAVIES & HUNT,
Chartered Patent Agents, 321, High Holborn, London, W.C.,
Agents for the Applicant.