Improvements in or relating to the Driving Gear of Bicycles and the like.
Year: 1898

page_text: Date of Application, 23rd Sept., 1898-Accepted, 5th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in or relating to the Driving Gear of Bicycles
and the like.
I, SAMUEL OTIS WILBOR, of Little Compton, in the County of Newport and
State of Rhode Island, United States of America, Farmer, 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 driving gear of bicycles and the like, and the
object thereof is to mount the driving cranks diametrically across the face of the
[sprocket wheels and secured thereto at or near the periphery thereof, whereby
increased power and steadier turning of the sprocket wheel is attained.
These and other objects and advantages will be hereinafter more fully described,
shown in the accompanying drawing, and particularly pointed out in the claim.
In the drawing
Figure 1 is a side elevation of my invention.
Figure 2 is a top plan view thereof.
Figure 3 is a detail perspective view of the crank.
0
Like numerals of reference designate corresponding parts in all the figures of
the drawing.
Referring to the drawing, 1 and 2 designate a pair of driving sprockets arranged
upon opposite ends of the driving shaft. Secured diametrically across the outside
face of each sprocket wheel is the driving crank 3. This crank is composed of
two integral arms or members 4 and 5, the arm 5 forming the attaching portion,
while the arm 4, carries a suitable pedal at its outer extremity through the hole 6
provided therein.
The crank is flattened and broadened intermediate its ends, as at 7, to provide
lobes or ears 8 extending at opposite sides of the crank. This flattened portion
is applied to the outer face of the sprocket wheel near its periphery with the arm 5
extending diametrically across the face of the sprocket to, or nearly to, the
periphery upon the opposite side thereof. The crank is secured in this position
by means of bolts or screws 9 passing through openings 10 in the ears 8 and by
a similar fastening 11 passing through an opening 12 in the outer extremity of
arm 5.
This method of attachment brings the pressure or force at opposite points upon
the periphery of the sprocket, thereby increasing the power and maintaining a
more even and steadier pressure than when the force is applied to the shaft at the
centre of the sprocket, as is the common method of attachment.
It will be noted that the arms 4 and 5 are not arranged in the same plane, but
are offset one from the other in parallel planes, the flattened portion 7 being in
the same plane with the arm 5 so as to attach the same evenly to the sprocket,
and the arm 4 in a plane outside that of the arm 5, so as to accommodate the
fastening of the pedal on the inside of the arm 4 and space the same away from
the chain so as not to interfere therewith in the turning of the sprocket. This
will be readily understood, for if both arms 4 and 5 were in the same plane flush

page_text: with the outside face of the sprocket wheel, the nut or fastening for the pedal
would extent inward from the hole 6 in the outer end of arm 4 and across the
plane of the sprocket. Therefore as the crank comes up from underneath, said
nut would strike the chain and could not pass the latter without breaking it.
Thus the offset feature of the arms of the crank is very important and provides
a useful and novel form of crank.
It is not essential to my invention that two sprocket wheels be used, as one
crank may be attached as herein described, and the other may be mounted in any
preferred-manner.
Changes in the form and minor details may be made without departing from
the spirit and scope or sacrificing any of the advantages of my invention, and
therefor I do not wish to be understood as limiting myself to the precise formation
and arrangement as herein described.
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
1. A drive crank comprising two arms extending in the opposite directions,
said arms being offset from each other and arranged in parallel planes, one of the
arms being adapted to be attached diametrically across the face of a drive wheel
or the like, substantially as shown and described.
2. A drive crank comprising two arms extending in opposite directions, said
arms being offset one from the other and arranged in parallel planes, and ears
formed at each side of the inner end of one of the arms, the latter arm being
arranged diametrically across the face of a drive wheel or the like with the ears
near the periphery of the wheel and the other end of the arm near the opposite
periphery thereof, and fastenings passing through said ears and the outer
extremity of the arm respectively, into the wheel, substantially as shown and
described.
3. A drive crank comprising two integral arms extending in opposite directions,
said arms, being offset one from the other and arranged in parallel planes, one of
the arms being broadened and flattened at its inner end forming ears at opposite
sides thereof, the said broadened portion connecting the arms together, substan-
tially as shown and described.
Dated
this 2nd day of September 1898.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.