Improvements in Variable Oranks.
Year: 1894

page_text: 3'
Date of Application, 22nd May, 1894 Accepted, 23rd June, 1894
CUMI LEIE DIEVITTUATION.
Improvements in Variable Oranks.
We CHARLES HENRY DAVIDS of 877 Gates Avenue, Brooklyn in the County
of Kings and State of New York, United States of America, Mechanical Engineer,
and JOHN STEWART of 374 Canal Street, New York in the County and State of
New York, United States of America, Manufacturer, 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 :-
Our invention relates to improvements in variable cranks in which provision is
made for changing the length of the crank by a rotary movement of it relatively to
its support upon the axle.
It is particularly well adapted to use in connection with the drive shaft of a
velocipede, for purposes of increasing the leverage; in driving the velocipede up
inclines, and decreasing the leverage when on a level, thereby rendering it practicable
to gear the velocipede to a higher rate than would otherwise be feasible.
For purposes of illustrating, the practical use of the crank, we have shown it as
applied to the drive shaft of a bicycle.
In the accompanying drawings:-
Fig. 1 shows the crank as it appears in side elevation, looking toward" the
wheel..
Fig. 2 is an edge or plan view of the same.
Fig. 3 is an inside view in elevation, a portion of the rim being broken to
away, t
show the locking dog, and the crank being located in its extended adjustment
relative to the drive shaft.
Fig. 4 is a similar view, showing the crank in its shortened adjustment relative
to the drive shaft; and
change
Fig. 5 is a face view, in detail, of the disc to which the crank is swung to cha
its position relative to the drive shaft.
A represents the drive shaft. To it a circular bearing B is keyed or otherwise
secured; in the present instance, we have shown it as keyed to the shaft by a key b,
which extends through a hub b' extending laterally from the disc B, near the
margin thereof, the bore for the reception of the drive shaft A extending through
the disc B and the hub 3¹. For purposes of saving weight, and at the same time
rendering the disc B sufficiently strong, we have made it of skeleton form, and in
its periphery we have located, at suitable intervals, notches 6³, for the reception of
the nose of a locking dog carried by the crank. In the present instance we have
shown the notches so located as to permit the crank to be adjusted on the side
of the disc nearest to the drive shaft, on the side of the disc furthest from the
drive shaft, and at points intermediate of these positions. It is obvious, however,
that, by increasing or diminishing the number of notches, the adjustments may be
increased or diminished, as may be found expedient.
The shank of the crank is denoted by C, and at its end, where it is connected
with the disc B, it is widened and hollowed out to form a housing for and fitted
with an easy rotary movement over the outer side periphery of the disc B. Such
widened portion of the crank, which covers the outer side of the disc B is denoted
by c and the rim which surrounds the periphery of the disc B is denoted by o'. The
crank C is pivotally secured at the centre of the disc B, as, for example, by a
pivotal stud bolt D, so that, when released, it may be swung around the disc B on
the pivot D. The crank is also hollowed out, forming a chamber for the
reception of the locking dog E, the nose e of which is fitted to enter the notches 6*
in the disc. The dog E is pivotted, as at e¹, within the chamber c³, and is extended

page_text: through to the outside of the chamber, and provided with an operating pedal or
hand piece e, which preferably projects over the rim of the crank, into convenient
position to be pressed upon by the heel of the rider, to rock the dog out of engage-
ment with the disc B. The nose of the dog is pressed normally toward the disc B
by a spring F, seated within the chamber between the back of the dog and the
wall of the chamber.
In operation, when it is desired to change the crank from its extended adjustment
-shown in Fig. 3-to its shortened adjustment, shown in Fig. 4, the dog E may be
released from the disc B, and the crank may then be swung around a half revolution,
or the disc B, keyed to the drive shaft, may be turned a half revolution while the
crank is held against turning, either of which operations will serve to adjust the
crank from its position on the disc B furthest from the drive shaft, into its position
thereon nearest to the drive shaft. In case it is desirable to adjust the crank to
the position intermediate of its most extended and shortened positions, such
adjustment may be effected by permitting the dog E to engage one of the notches
intermediate of those which lock it in its extreme adjustments.
It is obvious that slight changes might be made in the construction and arrange-
ment of the several parts, without departing from the spirit and scope of our
invention; hence we do not wish to limit ourselves strictly to the construction and
arrangement herein set forth, but what we claim is :-
1. The combination with a velocipede crank, of a circular bearing on the axial
line of which the crank is pivotted, the said bearing being provided with a plurality
of notches along its periphery, a spring actuated locking dog pivotted to the crank
with its operating arm accessible to the foot of the rider, the locking dog having
an engagement with the notches on the said bearing, to lock the crank positively to
the bearing, and means for securing the bearing excentrically to the drive shait of
a velocipede, substantially as set forth.
2. The combination with a crank provided with a recess, of a circular bearing
adapted to seat within said recess, means for pivotting the crank to the bearing on
the axial line of the latter, a spring-actuated dog pivotted to the crank in position
to engage the bearing, the said dog having an operating arm extended to the
exterior of the crank, and means for securing the bearing to a shaft, substantially
as set forth.
Dated this 22nd day of May 1894.
NEWTON & SON,
Agents for the Applicants.