Improvements in Cranks for Safety-bicycles and other Velocipedes.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in Cranks for Safety-bicycles and other Velocipedes.
I THOMAS KNOWLES of Norwood Road, Southport in the County of Lancaster,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to cranks for safety-bicycles and other velocipedes and has
for its object to increase the efficiency of such cranks as means for transmitting to
the axles on which they are mounted the force applied to such cranks by the riders
of the machines in which they are employed.
According to my invention I form each crank of a safety-bicycle or other
velocipede so that the pedal mounted upon it and consequently the foot of the rider
when propelling the machine may describe a circle of smaller diameter than that
which is described by a part of the crank which I cause to extend further from
the crank-shaft or axle on which it is mounted. Upon the part of the crank so
extended and at a suitable angle thereto I mount or form another part which
carries the pedal so that through the part so mounted or formed the thrust applied
to the pedal is conveyed to the part of the crank furthest extended from the
crank shaft or axle. The difference between the diameter of the circle which is
described by the pin or axle of the pedal and the part of the crank which is
furthest extended from the crank-shaft or axle may be made as great as may be
considered desirable. I also propose to so form the said crank that when it is
being revolved in the direction in which it is revolved to propel the machine in
which it is employed forwards the axis of the pin or axle of the pedal mounted
upon such crank shall not pass through a plane containing the axis of the crank-
shaft or axle on which the said crank is mounted until after the axis or central
line of the part of the said crank which is upon or adjacent to the axis of the said
.crank-shaft or axle has passed through the said plane.
1 Dated this Seventeenth day of December 1895.
HOWARD CHEETHAM,
Manchester, Agent to the Applicant..
I, THOMAS KNOWLES, of Norwood Road, Southport, in the County of Lancaster,
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 :-
:
My invention relates to cranks for safety-bicycles and other velocipedes and has
for its object to increase the efficiency of such cranks as means for transmitting to
the axles on which they are mounted, the force applied to such cranks by the
riders of the machines in which they are employed.
According to my invention I form each crank of a safety-bicycle or other
velocipede so that the pedal mounted upon it and consequently the foot of the rider
when propelling the machine may describe a circle of smaller diameter than that

page_text: .
which is described by a part of the crank which I cause to extend further from
the crank-shaft or axle on which it is mounted. Upon the part of the crank so
extended and at a suitable angle thereto I mount or form another part which
carries the pedal so that through the part so mounted or formed the thrust applied
to the pedal is conveyed to the part of the crank furthest extended from the
crank-shaft or axle. The difference between the diameter of the circle which is
described by the pin or axle of the pedal and the part of the crank which is
furthest extended from the crank-shaft or axle may be made as great as may be
considered desirable. I also propose to so form the said crank that when it is
being revolved in the direction in which it is revolved to propel the machine, in
which it is employed, forwards the axis of the pin or axle of the pedal mounted
upon such crank shall not pass through a plane containing the axis of the crank-
shaft or axle on which the said crank is mounted until after the axis or central
line of the part of the said crank which is upon or adjacent to the axis of the said
crank-shaft or axle has passed through the said plane.
A crank formed according to my invention is illustrated in side elevation in the
accompanying drawing. In the crank illustrated in the accompanying drawing,
(a) is the part of the crank which extends further from the centre about which
the crank is caused to revolve than the pedal mounted upon such crank, and (b) is
the part formed upon the extended part (a) to carry the pedal, the pin or centre of
which is intended to be mounted in the hole formed in the terminal part (6') of the
part (b) of the crank. From the accompanying drawing in which the arcs drawn
in dotted lines are portions of circles, the centres of which are at (A) that is to
say in a line corresponding to the position intended to be occupied by the axis of
the shaft or axle upon which the crank would be mounted when in use, it is obvious
that in the rotation of the crank, the part (a) thereof will describe a circle larger
than that described by the axis or centre of the pedal mounted upon such crank
and that the difference between the circles described by the part (a) of the crank
and by the axis or centre of the pedal may be made greater or less according as
the part (a) of the crank and the part (b) thereof are made of greater or less
length. So long as the distance from the part (a) of the crank to the axis of the
shaft or axle on which the crank is mounted when in use is made greater than
the distance from the axis of such shaft or axle to the axis or centre of the pedal
mounted upon the said crank, the inclination of the part (b) of such crank to the
part (a) thereof may be made different in different cranks but I prefer to form
the part (6) of the crank of the size and inclination in relation to the part (a)
thereof, which are illustrated in the accompanying drawing. In the accompanying
drawing the arrow (B) indicates the direction in which the crank is caused to revolve
when in use.
Cranks formed according to my invention may be formed or provided
with any suitable devices or parts to enable them to he readily mounted upon or
secured to the crank-shafts or chain-wheels to which it may be requisite to apply
them.
The employment of a crank constructed according to my invention causes the
.pressure or force which is applied to the pedal mounted upon such crank when in
use in a velocipede by the rider of such velocipede to be transmitted from the pedal
to the axle or shaft upon which the crank is mounted through a part which is
further from the axis of the axle or shaft upon which such crank is mounted than
the centre or axis of the pedal and so causes such pressure or force to be more
advantageously applied to such axle or shaft than it would be if transmitted thereto
by means of a crank of the forni hitherto customary.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
For use in a safety-bicycle or other velocipede a crank so formed for the
purposes and substantially in the manner herein before described, that the axis of
the pedal mounted upon it shall when in use describe a circle smaller than that

page_text: which is described by a part of the said crank which is made to extend further
from the crank-shaft or axle on which such crank is mounted than the axis of such
pedal and that the said pedal is mounted upon a part mounted or formed at a
suitable angle to the part so made to extend."
Dated this Seventeenth day of September 1896.
HOWARD
CHEETHAM,
Manchester, Agent to the Applicant.