Improvements in Driving Gear for Velocipedes and other Vehicles
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after Amend-
ment (under Section 11 of the Patents, &c. Act, 1883) as required by the
decision of the Chief Examiner of the 19th day of March 1898.
Date of Application, 27th Nov., 1896
tinn Loft 27th Cont 4007
10th Nan
4007
PROVISIONAL SPECIFICATION.
Improvements in Driving Gear for Velocipedes and other Vehicles
We, WILLIAM NASCH, of 251, Whitechapel Road, Engineer, and HENRY ELLIS
HARRIS, of 64, Finsbury Pavement, Dentist, both in the County of London, do
hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in driving gear, for velocipedes and other
vehicles of the kind wherein the driving cranks are mounted on separate axles and
wherein the cranks move with variable velocity so as to overcome the effect of the
dead points in their revolution, the object of the invention being to provide more
simple mechanism than heretofore for transmitting the motion of the axles to the
chain wheel or the like.
In carrying out our invention we advantageously form one of the crank axles
hollow and adapted to receive the other axle and we connect each of the said
axles with a chain or sprocket wheel or ring mounted eccentrically to the crank
axles by a suitable combination of links so arranged that the crank axles are caused
to rotate with a varying velocity, that is to say, so that they make a quick return
movement.
A suitable arrangement of mechanism for transmitting the motion of the crank
axles consists of a crank mounted on each of the axles and connected with the
chain or sprocket wheel or ring by means of a connecting rod.
Or we may employ an arrangement of slotted links in which work pins or rollers
in connection with the crank axles.
In some cases we employ a cam or cams and an arrangement of links for trans-
mitting the motion of the crank axles.
Dated the 27th day of November 1896.

page_text: 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 driving gear, for velocipedes and other
vehicles, of the kind wherein the driving cranks inove with variable velocity so as
to overcome the effect of the dead points in their revolution, the object of the
invention being to provide more simple mechanism than heretofore for trans-
mitting the motion of the axles to the chain wheel or the like.
In carrying out our invention we advantageously form the driving axle in two
parts one of which is hollow and adapted to receive the other, and we connect each
of the said parts with a chain or sprocket wheel or ring mounted eccentrically to
the driving or crank axle by a suitable combination of links so arranged that the
two parts of the axle are caused to rotate with a varying velocity, that is to say,
so that they make a quick return movement.
A suitable arrangement of mechanism for transmitting the motion of the crank
axle consists of a crank mounted on each of the axle parts and connected with the
chain or sprocket wheel or ring by means of a connecting rod.
To enable our invention to be fully understood we will describe it by reference
to the accompanying drawings, in which:-
Figure 1 is a side elevation of bicycle driving gear made according to our
invention:
Figure 2 is a longitudinal section of the same on the line 2-2 Figure 1:
Figures 3 and 4 are detail views drawn to a larger scale of one of the connecting
rods or links.
a is the bottom bracket of the bicycle, is the hollow axle part mounted in ball
bearings therein and e is the solid axle part which is arranged to rotate inside the
hollow part band is supported in ball bearings d at each end as clearly shewn.
e, f are the cranks mounted upon the axle parts b and c and g is the chain or
sprocket wheel by means of which the motion of the cranks is transmitted to the
driving wheel of the bicycle. This chain or sprocket wheel or ring 9 is mounted
eccentrically to the divided axle and runs upon balls arranged around the inner
periphery of a dise A rigidly secured to the bottom bracket a. i, i are the connect-
ing rods or links which connect the axle parts b and c with the chain wheel g.
These connecting rods i, i are preferably of the construction shewn in detail in
Figures 3 and 4, that is to say, one end of each link is forked so as to embrace a
lug 6 (or ) upon the axle part b (or c) and the other end is provided with a
screw which passes through a hole in a lug g' on the chain wheel g.
The lugs g, g are arranged diametrically opposite to one another and the con-
necting rods i, i are made of the same length so that as the axle parts b, c are
eccentric to the chain wheel g it will be obvious that the two cranks e, f are not
at the dead points simultaneously. With this construction, therefore, as the cranks
are rotated by the rider they, on the completion of their downward stroke and on
passing the lower dead point, move upwards with greater velocity than they
possess whilst making their downward stroke owing to the eccentricity of the
chain wheel which varies the leverage of the cranks upon the chain wheel during
the revolution. It will thus be obvious that each crank, when it has made its
downward or operative stroke, is pulled upwards so as to again come into the
operative position before the other crank has reached the lower dead point thereby
enabling power to be continuously applied to the chain wheel by one or other of
the cranks.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we wish it to be under-
stood that we are aware of the Specification of James Cottrell No. 468 of 1889, and
we do not claim anything described and claimed therein, and we declare that what
we claim is:
The combination and arrangement of parts forming the improved driving

page_text: gear for cycles herein before described and illustrated in Figures 1, 2, 3 and 4 of
the accompanying drawings.
Dated this 27th day of September 1897.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.