Improvements in and connected with Cranks for Velocipedes and other Machines Driven by the Feet.
Year: 1896

page_text: Date of Application, 9th June, 1896
Complete Specification left, 30 h July, 1896-Accepted, 17th Oct., 1896
PROVISIONAL SPECIFICATION.
Improvements in and connected with Cranks for Velocipedes and
other Machines Driven by the Feet.
I JOHN HUTSON of 55, Holborn Viaduct, London, in the County of Middlesex,
do hereby declare the nature of this invention to be as follows:-
The object of this invention is to construct cranks for velocipedes and other
machines driven by the feet with a variable throw the crank arm gradually
lengthening during its downward movement and shortening as the crank rises or
by rotating the pedal half a revolution the crank arm may be lengthened while
ascending and shortened while descending thus enabling the rider when "back
pedalling" to bring his machine to rest in a shorter time than he could do with the
ordinary cranks.
Now according to this invention I form the cranks for velocipedes and other
machines driven by the feet in two portions one portion sliding in or on the
other.
One portion of the crank is secured to the crank shaft or axle and the other
portion to the pedal pin. To the pedal I attach an excentric cam or sheave which
cam or sheave revolves in a strap attached to a rod, the other end of which rod is
pivotted to the other portion of the crank at any suitable distance from the crank
shaft.
As the centre of the excentric sheave does not coincide with the pedal pin it
follows that as the crank rotates if the pedal is prevented from turning the crank
will be gradually lengthened and shortened, the crank being lengthened during the
downward movement of the pedal, thus enabling the power applied to the pedal to
be transmitted to the crank axle at an increasing leverage as the crank approaches
its horizontal position or other position of maximum mechanical advantage.
If, however, the pedal is rotated half a revolution on the pedal pin the crank
will be lengthened as the pedal ascends and shortened as it descends thus giving
the person operating the cranks more control over the machine wben back pedalling
than can be obtained with ordinary cranks. The difference between the maximum
and minimum lengths of crank arm may be so adjusted that the foot of the rider
travels in a circle or other curve no larger than at present.
The excentrics and straps and sliding portions of the cranks may be fitted with
ball bearings if desired.
Dated this 8th day of June 1896.
Improvements in and connected with Cranks for Velocipedes and
other Machines Driven by the Feet.
I, JOHN HUTSON, of 55 Holborn Viaduct, in the County of Middlesex, 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 cranks so constructed that the leverage or effective

page_text: length thereof is automatically and constantly changed as the crank is rotated from a
maximum at one part of the revolution to a minimum at another part of the revolution
the object being to so arrange that without unduly increasing the diameter of the circle
described by the crank pin, or pedal in the case of a pedal crank, great leverage
shall be obtainable at that part of the revolution where the power can be most
effectively applied. The chief feature of my invention is the construction whereby
the pedal is mounted on an eccentric sheave in the crank. My improvements are
intended more especially for application to velocipede pedal cranks but they can
be applied to other cranks whether driven by the foot or otherwise. The chief
advantage of my improved pedal cranks as applied to velocipedes is that while
retaining the circular movement of the pedal to which cyclists are used and without
increasing the throw of the pedal, and consequently the up and down movement of
the foot, a greatly increased leverage and therefore more power to propel the
machine is obtained when the crank is descending. Another advantage of my
improved pedal is that it affords means for instantly effecting a change when back
pedalling is required so that the increased leverage of the crank coincides with the
upward movement of the crank instead of with the downward movement.
and
Referring to the accompanying drawings
Figure 1 is a side view of a pedal crank constructed according to my invention,
Figure 2 is a sectional plan on the line a, a, Figure 1.
Like letters denote corresponding parts in both figures.
The crank proper A is constructed at A¹ with any ordinary or suitable means
for securing it to the crank axle, and is enlarged at its other end to receive a
circular frame, ring or eccentric sheave B which carries the pedal. The said
ring B is perfectly free to turn in the crank and is preferably supported by balls b
as seen in Figure 2 to reduce the friction to a minimum. The pedal C instead of
being mounted loosely on the pedal pin C¹ as in ordinary pedal cranks is rigidly
fixed to said pin which in its turn is secured to a block D that is supported in a
slot or channel B formed in the frame or ring B. The block D is placed at one
or the other end of the slot B according as the pedal crank is to be used for
forward pedalling or for back pedalling. Any suitable catch may be provided to
prevent accidental displacement of the block after it has been adjusted at either
end of the slot. In the construction shown in the drawing the catches consist
of balls E E, carried by spring plates E', E', secured at their middle to the ring.
These balls project into the slot B and bear against the edge of the block D.
When it is desired to move the pedal along the slot all that it is necessary to do is to
push or draw it in the proper direction by the hand or foot, the balls being thereby
raised or separated to allow the block D to pass between them after which they
close in again and retain the block in its new position.
When pedalling with this crank the foot operates to maintain the pedal
substantially horizontal except for the slight oscillation due to the action of the
ankle, the result is that the ring or frame B is prevented from rotation and con-
sequently during one half the revolution of the crank the pin C¹ is on the side of
the centre of the ring B remote from the crank axle and during the other half of
the revolution the pin C' is on the axle side of the centre of the ring, and the
effective length of the crank gradually varies from a maximum equal to the length
from the axle to the centre of the ring B plus the distance from the centre of the
said ring to the pin C¹ to a minimum which is equal to the distance from the axle
to the centre of the ring B less an amount equal to the distance from the centre
of the said ring to the pin C. For forward pedalling the maximum length of the
crank is arranged to coincide with about the middle of the down stroke and the
minimum length with about the middle of the up stroke of the pedal and vice versa
for back pedalling. The change is effected by simply sliding the block D along
the slot B¹ or if desired by turning the ring 1 through half a revolution. A heel
piece may be provided on the pedal to facilitate the moving of the pedal in the
slot when required by means of the foot and for affording greater leverage for

page_text: keeping the pedal horizontal. The extent of the up and down movement of the
foot is only the same as it would be with an ordinary crank equal in length to the
distance between the axle and the centre of the ring B while it is obvious that
the effective length of the crank during the down stroke for forward pedalling or
during the up stroke for back pedalling is considerably augmented and therefore-
greater propelling or retarding power as the case may be is obtained.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. A pedal or other crank having its pedal or crank pin mounted eccentrically in
a ring which can turn in the crank, substantially as and for the purposes specified.
2. In the pedal crank referred to in the preceding claiming clause the pedal pin
secured to a block which can slide in a slot in the ring but cannot turn therein,
substantially as and for the purpose specified.
3. A pedal crank constructed substantially as described with reference to the-
accompanying drawings and operating as and for the purposes specified.
Dated this 30th dox of July 1896
JNO. HUTSON,
55 Holborn Viaduct, W.C..