Year: 1895

page_text: I, MARK GREEN, of Victoria Road, Middlesbrough-on-Tees, in the County
of York, Joiner, do hereby declare the nature of this invention to be as
follows:-
This invention relates to the pedal leverage of cycles, and is intended to effect
an improvement in the direction of increased leverage effected through the pedal
crank.
Pedal cranks are usually secured as fixtures to the pedal crank shaft or to the
boss of the pedal crank shaft wheel, extending therefrom as a radial arm, the
leverage of which over the chain wheel varies of course with the length of the said
radial arm.
By my invention I provide a lever mounted on the pedal crank shaft as a
fulcrum, the short arm of which is pivoted to the web or arm of the chain wheel,
whilst the longer arm extends radially from the pedal crank shaft as before.
In this way I combine a double armed lever with the chain wheel, the shaft of
which is the fulcrum of the lever, as a means of driving the cycle, the mechanical
advantage of which arrangement is due in the first place to the relative lengths of
the two arms of the crank lever.
Dated this 11th day of Februare 1895.
G. J. CLARKSON,
Chartered Patent Agent,
Stockton-on-Tees, Agent for the Applicant.
I, MARK GREEN, of Victoria Road, Middlesbrough-on-Tees, in the County
of York, Joiner, 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 the pedal leverage of cycles and is intended to effect
an improvement in the direction of increased leverage effected through the pedal
crank.
Pedal cranks are usually secured as fixtures to the pedal crank shaft or to the
boss of the pedal crank shaft chain wheel extending therefrom as a radial arm the
leverage of which over the chain wheel varies of course with the length of the said
radial arm.
By my invention I provide levers mounted on the pedal crank shaft as a
fulcrum, the short arm of which is pivotted to the web arm or equivalent part of
the chain wheel, whilst the longer arm extends radially from the pedal crank shatt
as before. In this way I combine double armed leverage with the chain wheel,
the shaft of which is the fulcrum of the lever, as a means of driving the cycle, the
mechanical advantage of which arrangement is due in the first place to the relative
lengths of the two arms of the crank lever and the same improvement is applied to
the leverage of the opposite pedal in the manner hereinafter described.

page_text: And in order that my invention may be fully understood and readily carried into
effect, I will now proceed to describe the same with reference to the drawing
hereto annexed in which Figure 1 illustrates in front elevation on the chain wheel
side the improved pedal leverage constructed according to my invention and
Figure 2 is a corresponding part sectional view thereof taken practically along
line ax in Figure 1.
In the drawing a is the pedal crank shaft onto which is mounted as its fulcrum
the lever, the short arm of which is pivotted at a to the web or arm of the
chain wheel d or to an intermediate position as shown by means of the cross-piece e,
whilst the longer arm b extends radially from the pedal crauk shaft as before. In
like manner at the opposite end of the pedal crank shaft is mounted another similar
double armed lever ff the short arm of which is pivotted to the radial arm g by
means of the pin h, the said radial arm extending from the shaft a to which it is rigidly
secured, whilst the longer arm fextends radially from the pedal crank shaft as
before. This mode of construction ensures symmetry of parts for working each
pedal. In order to tighten up the crank levers and ff and so prevent
"sagging" or side play I furnish conical bearings or bushes tapped and screwed
onto each end of the pedal crank shaft, the said bearings being also flanged in the
manner shown and accurately fitted into corresponding recesses formed in the levers
to receive them as shown more particularly in Figure 2 it being understood that
the said bushes jj share the rotation of the pedal crank shaft a and not that of the
double armed levers. But this particular device is only to be taken as a suitable
and convenient way of effecting the purpose for which it is used and not as
essential features of my invention. In this way I combine the two double armed
levers and ff' with the chain wheel, the shaft of which is the fulcrum of each
lever, as a means of driving the cycle, the mechanical advantage of which
arrangement is due in the first place to the relative lengths of the two arms of the
said crank levers and I find in practice that about 6 to 2 is a suitable ratio to
apply to the arms for the purpose of my invention but I do not of course restrict
myself rigidly to this particular ratio.
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 :-
In the driving mechanism of cycles the use in combination with the chain wheel
of such driving mechanism of double armed pedal levers mounted on the pedal
crank shaft of the chain wheel as their fulcrum, constructed, arranged and operating
as an improved means of driving the cycle, substantially as hereinbefore described
with reference to the accompanying drawing.
Dated this 4th day of November 1895
G. J. CLARKSON,
Chartered Patent Agent,
Stockton-on-Tees, Agent for the Applicant.
G. J. CLARKSON,
Chartered Patent Agent,
Stockton-on-Tees, Agent for the Applicant.