An Improvement in Velocipedes.
Year: 1889

page_text: Date of Application, 12th Nov., 1889
Complete Specification Left. 1st Aug.. 1890-Accepted. 6th Sept. 1890
PROVISIONAL SPECIFICATION.
An Improvement in Velocipedes.
I, BEWICKE BLACKBURN, of 12 Calverley Park, Tunbridge Wells, in the County of
Kent, do hereby declare the nature of this invention to be as follows:-
In working the pedals of a velocipede, the leg of the rider exerts comparatively little
strain when the crank is beginning its descending stroke, the leg being then consider-
ably bent, but as the crank descends the leg in straightening itself, for a time delivers
a greater strain which again becomes less as the crank approaches the end of its down
stroke.
The object of my invention is to equalise to a certain extent the strain conveyed
from the crank shaft through chain gearing to the driving axle or wheel. For this
purpose, instead of using circular chain wheels I employ wheels of a quasi elliptical
form, fixing the wheels with their longer axes in such positions that when the pedal
begins its descent the crank wheel acts with considerable leverage, as the wheel revolves
this leverage becomes less and less until it reaches its minimum and after this the
leverage is again increased, until the half revolution resulting from the descent of the
pedal is completed.
Dated this 12th day of November 1889.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Velocipedes.
I, BEWICKE BLACKBURN, of 12 Calverley Park, Tunbridge Wells, in the County of
Kent, 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:-
In working the pedals of a velocipede, the leg of the rider exerts comparatively little
strain when the crank is beginning its descending stroke the leg being then consider-
ably bent, but as the crank descends the leg in straightening itself, for a time delivers
a greater strain which again becomes less as the crank approaches the end of its down
stroke.
The object of my invention is to equalise to a certain extent the strain conveyed
from the crank shaft through chain gearing to the driving axle or wheel. For this
purpose, instead of using circular chain wheels I employ wheels of a quasi elliptical
form, fixing the wheels with their longer axes in such positions that when the pedal
begins its descent the crank wheel acts with considerable leverage, as the wheel revolves
this leverage becomes less and less until it reaches its minimum and after this the
leverage is again increased, until the half revolution resulting from the descent of the
pedal is completed.
The accompanying drawing is a side view of a quasi elliptical chain wheel according
to my invention, with chain pulley driven from it, shewing the position of the pedal
crank in relation to the wheel and pulley. A is the chain wheel with its teeth a
arranged at equal intervals as usual, and B is the toothed chain pulley driven from it.
The pedal crank C is nearly in line with the minor axis of the wheel A. Although
there is a slight difference in the length of chain engaged in different positions of the
wheel A, this difference is not more than can be allowed for by the elasticity of the
Lahain

page_text: 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 :-
The use in a velocipede of a quasi elliptical chain wheel on the pedal ax., sub-
stantially as and for the purpose set forth.
Dated this 1st day of August 1890.