Improvements in Velocipedes, also Applicable to other Machines Worked by Cranks or Pedals.
Year: 1887

page_text: TRUVIDIONAL
Improvements in Velocipedes, also Applicable to other Machines
Worked by Cranks or Pedals.
I WILLIAM GIFFARD of 23 New Bailey Street Salford in the County of Lancaster
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention consists in increasing the length of the crank or cranks, in such
manner that the crank or cranks shall be longer on the downward stroke and shall be
shorter on the upward or return stroke or half revolution.
To effect this one method is to form the crank or cranks each in two parts, one
part sliding into or on the other, the said sliding part carrying on the one side the
pedal or foot part of the crank or cranks, and on the other an antifriction bowl or
bowls working in a cam path or paths or their equivalent, attatched to the framing
of the machine, the said cam or cams or their equivalent causing the crank or cranks
to be longer on the downward stroke and shorter on the upward or return stroke
or half revolution. The same result being obtained by any other convenient
arrangement.
1007
WILLIAM GIFFARD.

page_text: COMPLETE SPECIFICATION.
Improvements in Velocipedes, also Applicable to other Machines
Worked by Cranks or Pedals.
1 WILLIAM GIFFARD of 23 New Bailey Street, Salford, in the County of Lancaster,
Engineer, 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 :-
My invention relates to pedal mechanism more especially for working velocipedes
but is applicable to other machines to be operated by the feet of the driver and its
object is to give increased leverage in the descending half of the rotation of each
crank when the pressure of the foot is operative in propelling and reduced leverage
in the ascending half of the rotation when the foot is lifted and at the same time to
cause the feet to describe in driving the crank a nearly. circular course or one but
slightly elliptical.
One mode of carrying out my invention consists in forming the arm of each crank
with a sleeve. or part that can slide to and fro on the crank arm, the pedal swivel for
the foot to press upon being carried upon the sleeve or sliding part which can thus
move to and from the axis of the crank, this movement being governed by one or
more bowls or studs, secured in the frame of the sleeve or sliding part which bowl or
bowls work in a circular path formed upon or fixed to the framing of the machine,
this circular path being excentric to the crank shaft so as to bring the pedal swivel
away from the crank axis and lengthen the crank arm for the downward stroke, and
vice versa for the upward stroke of the pedal.
According to another modification the object of my invention is carried into effect
by jointing the crank pin with a lever having two arms one arm being short extending
forward and being in an oblique position in relation to the other long arm of the lever
extending backwards, the end of which is jointed with one end of a radius rod the
fulcrum end of which rod is jointed to the framing-This arrangement gives increased
leverage upon the crank at the pedal swivel end of the lever for the downward push
of the feet, the motion of the pedal swivel being nearly circular.
-
Fig is a side elevation of part of a Bicycle having my improved pedal mechanism.
applied thereto and fig. 2 is a transverse sectional elevation of the pedal mechanism
detached showing one crank at its highest position when being pushed down by the
foot and the other at its lowest position when the foot is about to ascend.
a is the arm from the crank axle ', of the driving wheel b; upon the crank arm a,
a sleeve d¹ is fitted to slide upon the arm a, to and from the crank axle 6¹ this sleeve
forms one corner or part of a frame d, having three studs secured in it for three
bowls d' which bowls enter a box e having an annular slot in front for the studs to
pass through, the box being circular and is secured to or forms part of the framing of
the Bicycle There is one circular box pathe on each side of the driving wheel b,
one for each crank and placed excentric to its axle b¹.

page_text: It will be seen that as the crank arm a rotates, the pedal swivel d³ which is on a
stud projecting from the side of the frame d will move to and from the crank
axle b¹.
In the position in which it is shown in fig. 1 one pedal swivel d³ is at its greatest
leverage for the downward stroke and the other at its least leverage for the ascending
stroke.
Fig. 3 is a side elevation illustrating the second modification of my invention as
applied to a well known construction of Bicycle, and fig. 4 is a plan view of the pedal
mechanism detached, d is a lever jointed to the pin a¹ of the crank arm a, the long
arm of this lever d is jointed to a radius rod g the fulcrum end of which is jointed to
the boss for the bearing of the driving wheel bor to a stud on the framing.
The short arm d' of the lever d is bent to an oblique position in relation to the long
arm d and has a slot in it for the stud d of the pedal swivel d³.
Each crank has the same arrangement of lever d and rod and thus it will be seen
that each foot has increased leverage in the descending propelling push.
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. The combination of pedal mechanism with velocipedes and other pedal driven
machines where the leverage is increased for the descending push of the foot,
substantially as hereinbefore described and illustrated by figs. 1 and 2 of the drawings
and by figs. 3 and 4 of the drawings.
2. The arrangement and combination of mechanism with velocipedes substantially
as hereinbefore described and illustrated by figs. 3 and 4 of the drawings.
WILLIAM GIFFARD,
Applicant.