An Improved Pedal Crank for Cycles.
Year: 1895

page_text: Date of Application, 26th Sept., '1895
Complete Specification Left, 25th July, 1896-Accepted, 29th Aug., 1896
An Improved Pedal Crank for Cycles.
I, CHARLES HUNT, of Oakley Road, Redditch, in the County of Worcester,
Needle Scourer, do hereby declare the nature of this invention to be as follows :—
By means of this, my invention, the foot of the cyclist when in action, instead
of taking a circular motion, takes an elliptic, or ovoid one, which approaches more
nearly the action of the foot in walking, and this movement of the foot in an
ellipse, or ovoid, I obtain by constructing the crank shaft of the cycle in such a
manner that when the downward pressure of the foot is exerted upon the pedal
the crank shaft is elongated so far as the stroke extends, and when this pressure is
taken off and the crank shaft is resuming its position for the next downward
pressure of the foot, it becomes shortened, so that the foot of the cyclist has a
more direct movement towards this position than it could have if it had to follow
a circular movement. Thus as the downward pressure is exerted the crank shaft,
by my invention, is lengthened and a greater leverage is obtained, and on the foot
of the cyclist returning towards the point of pressure again, the shaft of the crank
is shortened so that the foot of the rider has a shorter distance to travel and a
more direct return than it could have were it obliged to follow a purely circular
movement.
And I accomplish this by making what I have called the shaft of the crank, of
two pieces of metal, (denoted by A. and B. respectively in the accompanying
drawings) the shorter one A being attached in the usual manner to the crank. axle
at C., and the longer one B carrying the pedal D. D. which is attached to the
pedal axle E., running upon ball bearings in the usual manner, in the nearly
circular extremity of the part B.
These two parts A. and B. of the crank shaft are connected by pieces of
metal F: F. working 'freely upon pivots at each extremity of each in the same
manner as do the connections of a parallel ruler; while to the lower extremity of
the part A. of the crank shaft, I attach in the same manner the connection 'G. the
opposite end of this connection working in a similar manner upon a pivot near the
circumference of the disc H. H. H. fixed upon the axle E. of the pedal D. D.
which axle passes through and revolves within a central opening in the nearly
circular extremity I. I. of the part B of the crank shaft.
And in both of the accompanying drawings the same parts of my improved
pedal crank are denoted by 'the same letters of reference, and Fig. 1. represents
the pedal crank at the shortest point of.its revolution, and Fig. 2 its appearance at
the point of its greatest elongation; and the pedal crank can be adjusted. on its
axle in such a manner that the"" throw" or "stroke" shall suit the position of the
rider.
And though in the drawings I have represented the part B. of the crank shaft
as straight, I may if I prefer to do so; curve the lower extremity terminating in I. I.
so that the nearly circular part of this and the "dise H. H. H. which it carries,
shall be in a direct line with the part A of the crank shaft, while the disc H.HH.
may be provided with ball bearings for the purpose of diminishing friction between
this and the part I: I.
And a 'crank made in accordance with my invention is an improved one, inasmuch as
when the pressure of the 'rider's foot is most exerted in the act of pedalling, the
crank'shaft is elongated under this and the greater power is gained, while where

page_text: this pressure has to be no longer applied, the crank shaft shortens and the distance
over which the foot has to travel is diminished, and the result is less fatigue to
the rider than would be the case if his foot had to continue a perfectly circular
motion.
Deted 24th September 1905
An improved Pedal Crank for Cycles..
1, CHARLES HUNT, of Oakley Road, Redditch, in the County of Worcester,
Needle Scourer, do hereby declare the nature of this invention and in what mauner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
By means, of this my invention the foot of the cyclist when in action instead of
taking a circular motion, takes an elliptic, or ovoid one, which approaches more
nearly the action of the foot in walking and this movement of the foot in an
elliptic, or ovoid, I obtain by constructing the crank shaft of the cycle in such a
manner that when the downward pressure of the foot is exerted upon the pedal
the crank shaft is elongated so far as the stroke extends, and when this pressure is
taken off and the crank shaft is resuming its position for the next downward
pressure of the foot, it becomes shortened, so that the foot of the cyclist has a more
direct movement towards this position than it could have if it had to follow a
circular movement. Thus as the downward pressure is exerted the crank shaft,
by my invention lengthened and a greater leverage is obtained, and on the foot
of the cyclist returning towards the point of pressure again, the shaft of the crank
is shortened so that the foot of the rider has a shorter distance to travel and a
more direct return than it could have were it obliged to follow a purely circular
movement.
In order to more particularly explain this my invention I have appended here-
unto illustrative sheets of drawings upon which are figures and numbers of
reference, similar numbers referring throughout the several views to the same thing
or part.
Fig. 1 shows this my invention as it would appear when travelling in the upward
direction.
Fig. 2 shows the invention as seen in the downward direction, and at its longest
point.
Fig. 3 is a plan view of Fig. 1.
Fig. 4 is a sectional view of a pedal with its connection to the crank shaft.
Fig. 5 shows a modified manner of coupling the two parts of the crank shaft.
I make the shaft of the crank of two pieces of metal (denoted by 8 and 8*
respectively in accompanying drawings) the shorter one 8 being attached in the
usual manner to the crank axle at 9, and the longer one 8 carrying the pedal 10
which is rigidly attached to the pedal axle 11.
This rigid attachment may be made in any suitable manner, although I have
shown it so made by the bolts 12 12 passing right through the pedal barrel 13 and
also through the spindle. The spindle 11 is further carried upon the shaft piece 8*
by any suitable arrangement of ball bearing or bearings. I have shown one way
in which this may be done as will be seen in Fig. 4.in which at the one end of the
spindle 11 is formed the crank disc 14 having a ball race for balls 15. Coincident
with this ball race is a similar ball race in the shaft piece 8*. A sliding plate 16
is now passed on the spindle 11 having a similar ball race for balls 17. Behind
this comes the pedal 10 which may be lengthwise adjusted by the lockouts at 18 to
regulate the bearings at 15 and 17, that is the pedal 10 and the spindle 11 are
carried as one in the said bearings at 15 and 17. These two parts 8 and 8* of the

page_text: crank shaft are connected by links 18, working freely upon pivots at 19 in the
same manner as do the connections of a parallel ruler; while to the lower extremity
at 20 of the part 8 of the crank shaft, I attach the connecting rod 21; the
opposite end of this rod 21 working in a similar manner upon a crank pivot 22
near the circumference of the disc 14.
And though in the drawings I have represented the part 8 of the crank as.
straight, I may if I prefer to do so, curve it so that the centres of the bearings.
and of the main crank 9 shall be in a direct line.
In Fig. 5 as before intimated I have shown how I may dispense with the
links 18, 18 by making the part 8 to slide within the box sleeve part 23, which.
said sleeve would be preferably made as long as possible both for strength and
steadiness of motion. If desired balls may be employed between the rubbing
surfaces within the said sleeve.
Thus it will be seen that when the pressure of the riders foot is most exerted in
the act of pedalling as seen in Fig. 2 the crank shaft is elongated and the greater
power is gained, whilst in the return or upward stroke as seen in Fig. 1 where the
pressure has to be no longer applied the crank shaft shortens and the distance over
which the foot has to travel is diminished, and the result is less fatigue to the rider
than would be the case if his foot has to continue a perfectly circular motion.
Having now particularly described and ascertained the nature of this my said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination in a pedal crank of the two parts 8, and 8" connected.
respectively to the main crank spindle and the pedal, with the rod 21 and crank
pin 22 carried from pedal spindle 11 constructed and operating substantially as set.
forth and illustrated upon the drawings.
Dated this 24th day of July 1896.
CHARLES T. POWELL,
Applicant's Agent.