Improvements in or connected with Crank Mechanism for Velocipedes.
Year: 1894

page_text: Date of Application, 16th Mar., 1894
Complete Specification Left, 17th Dec., 1894-Accepted, 19th Jan., 1895
PROVISIONAL SPECIFICATION.
Improvements in or connected with Crank Mechanism for
Velocipedes.
I, AUBREY FREDERICK SPENCER, of 20 Montpelier Crescent, Brighton, in the
County of Sussex, Brewer, do hereby declare the nature of this invention to be as
follows:-
:-
The invention has for its object improvements in, or connected with, crank
mechanism for velocipedes, with a view to obtaining greater leverage on the down
stroke without increasing the diameter of the circle travelled by the foot and
pedal.
For this purpose I employ an ordinary crank out, instead of mounting the pedal
on the outer end thereof as heretofore, I mount, in a bearing carried by the outer
end of the crank, an axis carrying a lever, the outer end of which carries the pedal.
In order to control this lever to retain a generally horizontal position during the
revolution of the crank, I fix a chain wheel rigidly on the bearing or frame carrying
the crank axle and another chain wheel on the axle mounted in the end of the crank
and carrying the pedal lever, and I pass around such chain wheels, a chain, which,
whilst permitting the free rotation of the crank, controls the pedal lever and causes
it to move in a parallel direction and retain its horizontal position.
In lieu of the chain and chain wheels, ordinary toothed wheels may be substituted
for such chain wheels and a loose intermediate wheel carried by the crank may be
substituted for the chain.
By the above construction of parts the pedal lever will, at the centre of the down
stroke, be extended in a line passing centrally through the crank, thereby giving
the leverage of both crank and pedal lever combined, whilst in travelling through
the remainder of the circle, the pedal will gradually approach the crank axle and
then gradually extend away therefrom.
Dated this 16th day of March 1894.
Improvements in or connected with Crank Mechanism for
Velocipedes.
I, AUBREY FREDERICK SPENCER, of 20 Montpelier Crescent, Brighton, in the
County of Sussex, Brewer, 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 invention has for its object improvements in, or connected with, crank
mechanism for velocipedes with a view to obtaining greater leverage on the down
stroke without increasing the diameter of the circle travelled by the foot and
pedal.

page_text: My invention is illustrated in the accompanying drawings, in which :-
Figs. 1, 2 and 3 are side elevations of my improved velocipede crank mechanism
fitted with chain gear and showing the parts in three different positions, and
Figs. 4 and 5 are respectively a side elevation and an edge view of such crank
mechanism fitted with toothed gear.
According to my invention 1 employ an ordinary crank a¹ fixed on the crank
axle a but, instead of mounting the pedal c on the outer end thereof as heretofore,
I adjustably mount, in a bearing a² carried by the outer end of the crank a', an axis a³
carrying a lever b, the outer end of which carries the pedal.
In order to control this lever b to retain a generally horizontal position during the
revolution of the crank a', I fix, as shown at Figs. 1, 2, 3, a chain wheel d rigidly
on the bearing or frame carrying the crank axle a and another chain wheel e on the
axle a³ mounted in the end of the crank a¹ and carrying the pedal lever b, and I
pass around such chain wheels d e, a chain f, which, whilst permitting the free
rotation of the crank a', controls the pedal lever band causes it to move in a
parallel direction and retain its horizontal position.
'
In lieu of the chain and chain wheels de, ordinary toothed wheels_d* e as
shown at Figs. 4 and 5, may be substituted for such chain wheels, and a loose'
intermediate wheel carried by the crank a', may be substituted for the
chain f.
By the above construction of parts the pedal lever will, at the centre of the
down stroke, be extended, as shown at Figs. 1, 4 and 5, in a line passing centrally
through the crank a', thereby giving the leverage of both crank a¹ and pedal lever b
combined, whilst in travelling through the remainder of the circle, the pedal c will
gradually approach the crank axle a as shown at Fig. 2, and then gradually extend
away therefrom as shown at Fig. 3.
C
Having now particularly described and ascertained the nature of my aid inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The improved construction of crank mechanism for velocipedes substantially
as herein shown and described.
2. A crank mechanism for velocipedes consisting of a crank a' fixed rigidly to the
crank axle a, a toothed wheel d fixed rigidly to the bearing or frame of the machine,
an axle a³ adjustably mounted at the outer end of the crank a', a toothed wheel e
loosely mounted on the axle a³ and rigidly connected to the pedal lever b, and a
chain passing around the two chain wheels de, substantially as herein shown and
described and for the purpose stated.
3. A crank mechanism for velocipedes consisting of a crank a¹ fixed rigidly to
the crank axle a, a toothed wheel d* fixed rigidly to the bearing or frame of the
machine, an axle a³ mounted at the outer end of the crank a', a toothed wheel e*
loosely mounted on the axle a³ and rigidly connected to the pedal lever b, and an
intermediate pinion f* gearing with the two wheels d*, e*, substantially as herein
shown and described and for the purpose stated.
Dated this 17th day of December 1894.
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.