Improvements in Pedal Oranks, and the Crank Shafts of Steam and other Engines.
Year: 1891

page_text: Date of Application, 22nd Oct., 1891-Accepted. 28th Nov., 1891
COMPLETE SPECIFICATION.
Improvements in Pedal Oranks, and the Crank Shafts of Steam and
other Engines.
We, WILLIAM PARFREY of 36 Richardson Street, Cycle Manufacturer and
WILLIAM DRURY of 13 William Street, Cutler, both of Swansea in the County
of Glamorganshire 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 the construction of cranks, by means of
which a greater leverage is obtained and more influence brought to bear upon the
revolving of the shaft or spindle, whereby a greater amount of work is derived
from the same initial motive power as compared with such cranks as hitherto made
and used.
Our invention consists, Firstly of a method of constructing the pedal cranks of
bicycles, tricycles and velocipedes generally, or fixing or attaching to the pedal
cranks of velocipedes as at present used, supplementary pieces or extensions so that
a forward throw, and extra leverage and power may be given to said cranks
without extending the distance between said pedals and the seat of the rider or
riders, and also of a special method of attaching said cranks to the driving spindle,
and Secondly of the application of the same principle in the construction of the
crank shafts of steam and other engines by forming a bend or curve in the cranks
thereof, so that these radiate from the shaft in a more or less crescent form instead
of in a straight line as at present made and used, and this applies equally whether
said cranks are formed integrally with the shaft, or keyed or otherwise fixed
thereto.
In order that our invention and the application thereof may be fully understood
we have appended hereunto a sheet of drawings in which
Fig. 1 is a side view of a pedal crank for velocipedes constructed according to
our invention.
Fig. 2 is a cross section of Fig. 1 taken anywhere centrally of its length.
Fig. 3 is a plan view, and Fig 4 is a side view of a curved supplementary piece
for attaching to ordinary straight cranks.
Fig. 5 is a plan view of a straight supplementary piece, the side view of which
would be similar to that of Fig. 4.
Fig. 6 is a view shewing the method of attaching Fig. 5 to an ordinary straight
pedal crank, Fig. 3 when employed in lieu of Fig. 5 would be connected thereto in
exactly the same manner.
Fig. 7 is a perspective view of one throw of the crank shaft of a steam or other
engine according to our invention.
Fig. 8 is a side view of an attachable crank for use in connection with such
shafts as Fig. 7, when the cranks are not formed integrally therewith.
We will first describe the application of our invention in connection with
velocipedes.
In carrying our invention into effect we construct of any suitable metal a pedal
crank A, which may be solid or hollow, and any desired shape in cross section, but
if solid, preferably that shewn by Fig. 2. Said crank is bent or curved at right
angles to any extent relatively to the driving spindle, but preferably not exceeding
that shewn by the dotted outline Fig. 1, or about 45°. The outward end of A
may be formed with a slot a for carrying the pedal in the usual way, the inner or
spindle ena is provided with a circular opening for the reception of the spindle and
formed with two jaws b and c so that A may be fitted to any size spindle, and may
be provided internally with a keyway, or with a key d as in Fig. 1. The jawe b

page_text: and c may be bored and tapped to receive a set screw. or bored plain to receive a
bolt and nut as at e Fig. 1, so that the drawing together of b and c retains A
firmly upon the spindle and easily and quickly removed when desired, and adaptable
for being fixed to either end. The crank A is by this means capable of being fixed
upon the spindle with the curve or bend thereof pointing in the same or opposite
direction to that of the rotation of the spindle, according to the nature of the
driving mechanism of the machine, but for machines propelled by a forward motion.
of the pedals, said curve or bend would be in the direction of the travel of the
machine. By this means a forward throw is provided which enables the rider or
riders to utilize the whole of the downward pressure of the foot without loss
occurring by dead centres.
In order that a forward throw may be obtained by the form of crank in general
use such as shewn by B Fig. 6, we may construct supplementary pieces, capable of
being attached thereto, either curved as at C Fig. 3, or straight as at D Fig. 5.
The former method C, may be of any degree of curvature not in excess of 45° and
is provided with a projection upon which is formed a screw thread g so that
when is placed within the sloth on B, a nut i may be screwed upon g to retain it
in position. When a forward throw of 45° is required the supplementary piece D
may be employed this also being provided with projection f and screw 9 for attach-
ment to B in the same manner as C, the only difference being that on D, the
projection f is crosswise wise, while that on C is lengthwise, a slot m is formed in
both C and D for the reception of the pedal. By this means we are enabled to
adapt the principle of our invention to the form of crank in general use, without
materially adding to the cost of the machine.
In adapting the principle of our invention to the crank shafts of steam and other
engines, we have found in practice that no definite rule can be given for the angle
of the curve or bend of the crank employed, this being governed by the surrounding
circumstances, but substantially that shewn by Figs. 7 and 8 or thereabouts. Fig. 7
shews the manner in which we prefer to construct said shaft when the cranks are
cast or otherwise formed integrally therewith. Fig. 8 is a side view. of said crank
when constructed separate from the shaft, and to which it may be attached by any
suitable means, either by that of a key engaging with a keyway formed in both the
crank E and the shaft F, or a keyway formed in E, and a key on F, or a keyway
formed in F and a key on E, or by means of screws passing through E into F, or
by shrinking, or any other way most suited to the size of the shaft being treated.
In Fig. 7 we have shewn only one throw, but it is obvious that the same principle
may be employed upon two or three throw shafts, and the throw of the cranks
constructed according to our invention would preferably be in the direction of the
rotation of the shaft when the most work was being performed.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we déclare that what we
claim is
for
1st. For improvements in cranks as applied to the pedals of velocipedes, the
construction and use of a solid or hollow crank A, of any shape in cross section,
provided at its lower end with jaws and c, carrying a bolt or screw e,
attaching A to the crank spindle with a key or keyway d in A engaging with a
key or keyway in the spindle and bent or curved at its upper end to any angle, and
provided with a slot a for the attachment of the pedals thereto, substantially as
and for the purposes herein described and shewn by Fig. 1 of the appended
drawings.
2nd. For improvements in the pedal cranks of velocipedes the construction and
use of strait or curved supplementary extension pieces D and C, provided with a
projection f, and screw, for attaching them to the straight ordinary pedal cranks
in general use for converting them in'o throw cranks substantially as and for
the purposes set forth and shewn by Figs. 3, 4, 5, and 6 of the accompanying
drawings.

page_text: 3rd. For improvements in the crank shafts of steam and other engines, the
employment of curved cranks, cast or otherwise formed integrally therewith or
attached thereto by means of a key and keyway or by any other suitable means,
substantially as described and shewn by Figs. 7 and 8 of the drawings hereunto
annexed.
4th. The application of curved or bent cranks to any form of revolving engine
shaft, or velocipede spindle substantially as and for the purposes herein set forth.
Dated this 21st day of October 1891.
GEO. THOS. HYDE,
4, Moorfields, Fore Street, London, E.C., Agent for the Applicants.