Improvements in and relating to the Driving Mechanism of Velocipedes.
Year: 1899

page_text: Date of Application, 10th Jan., 1899
Complete Specification Left, 10th Oct., 1893-Accepted, 11th Nov., 1893
Improvements in and relating to the Driving Mechanism of
Velocipedes.
I, JOSEPH ROE PARK, of Mount Pleasant, Norwich, in the County of Norfolk,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
This invention relates to an improved construction of crank and pedal for
velocipedes whereby the length of the crank is automatically increased.
"
According to this invention, I rigidly form on or attach to the pedal pin or
crank a cam, and I arrange the pedal or its equivalent with which- the rider's
foot engages so that it rests on the said cam. The pedal is connected to the
crank by means of one or more links or their equivalents pivotally attached both
to the pedal or its equivalent and to the crank or pedal pin. These supports are
preferably so arranged as to only allow the said pedal or its equivalent a move-
ment sufficient to enable the eccentric or cam to pass as the crank revolves.
It will be understood that the eccentric or cam is so shaped or arranged on
the crank or pedal pin that the effective leverage of the crank is increased during
a certain part of each revolution.
Improvements in and relating to the Driving Mechanism of
Velocipedes.
1, JOSEPH ROE PARK, of Mount Pleasant, Norwich, in the County of Norfolk,
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:-
..
This invention relates to 'an improved pedal-crank driving gear for velocipedes,
and it has for its object automatically increasing the effective throw of the crank
during a part of each revolution so as to obtain an increased leverage during
the operative part of the stroke.
In the accompanying drawing which illustrates one method of carrying this
invention into practice: -Figure 1 is a view in side elevation, Figure 2 is a view
in front elevation partly in section on line, », Figure 1 Figures 3 and 5 are
views showing modifications, and Figure 4 is a diagramatic view showing the
approximate positions of the pedal during a complete rotation of the crank.
Throughout the views similar parts are marked with like letters of reference.

page_text: On the end of each of the cranks A which are of the ordinary type is fixed
a pin B on which is rigidly mounted a cam C forming an extension of the crank.
On the pin B are pivotted-preferably by means of ball bearings as shown-
a pair of arms or links D, D, which are pivotally attached directly at their other
ends d to a plate E forming the pedal as shown by Figures 1, 2, 3, and 4 or
indirectly attached to said plate E by a second pair of arms or links D' as shown
by Figure 5. This plate is provided with side guides e, a rear toothed plate e¹
and front toe guard. The pedal plate E takes a hearing and rests on the cam C
or on a renewable plate so fixed on the underside of the said plate that it
may be renewed when worn.
1 find that hard wood is a satisfactory material for the cam E, but it will be
obvious that it may be made of other material without departing from the
spirit and scope of my invention.
With a view to decreasing the friction between the pedal plate E and the
cam C I may substitute three or more rollers C' for the said cam as shown by
Figure 3.
Although in the construction hereinbefore described and illustrated in the
accompanying drawing I employ one cam and two or more links for connecting
the pedal the arrangement may be reversed, the pedal being connected by one
or more links centrally arranged and supported by a pair of cams mounted on
the pin C one on each side of the said link or links.
It will be seen from Figure 4 that at the beginning of the operative part of
the stroke the pedal plate E bears on the cam C in such a position as to give
the greatest leverage of the crank, and that at the end of the effective part of the
stroke the said pedal plate is bearing on the cam so as to give the least leverage
of the crank, the intermediate positions being gradually obtained by reason of
the curved parts of the cam between these two points.
It will be obvious that the exact position of the cam with respect to the crank
will vary according to the increased amount of leverage desired during the
operative part of the stroke of the crank and also that the exact shape of the
cam will require to be varied according to the amount of ankle action employed
by the rider. In the diagram shown by Figure 4, the pedal plate is shown in
the approximate positions it will assume if the rider uses his ankle action most
effectually.
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-crank driving gear consisting of a pair of cranks of the usual
kind each carrying a cam at its outer end forming an extension thereof, of a
pedal pivotally connected to the end of the crank by one or more links so that
it takes a bearing on the periphery of the cam, as and for the purpose set forth.
(2) In combination, a crank for velocipedes, a cam-like extension thereof, and
a pedal connected directly or indirectly to the end of the crank by means of one
or more links, the arrangement being such that the pedal rests or seats itself
upon the cam-like extension of the crank, as and for the purpose set forth.
(3) The combination of parts herein before described and illustrated by the
accompanying drawing forming my improved pedal-crank driving gear for
valesinadas
Dated this 10th day of October 1899.
ROBERT E. PHILLIPS, Assoc. M. Inst. C.E., M. I. Mech. E.,
Chartered Patent Agent,
70, Chancery Lane, London, W.C., Agent for the Applicant.