Improvements in and relating to Velocipedes.
Year: 1890

page_text: Date of Application, 10th Apr., 1890
Complete Specification Left, 10th Jan., 1891-Accepted, 14th Feb., 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to Velocipedes.
I, WILLIAM CRAMPIN, of 24, Upper Thames Street, in the City and County of
London, Mechanic, do hereby declare the nature of this invention to be as follows:-
My invention relates to a device for giving increased leverage on the pedal crank
without increasing the throw of the crank or varying the radius of the path of
motion of the pedal, and it has for its object increased power and consequently a
saving of labour in propelling velocipedes.
I attain this object in the following manner;-I mount the pedal crank axle in
bearings in the usual manner, and I also mount cranks on the said axle and pedals
on the ends of the said cranks in the usual manner, but instead of mounting the
driving chain wheel on the pedal crank axle I mount it loosely on a disc fixed to
the frame of the machine eccentric with the pedal crank axle. I prefer to place
balls between the wearing faces of the disc and chain wheel forming a ball bearing,
and therefore reducing the friction between these parts. On the chain wheel is
formed or fixed a crank having at its free end a long slot adapted to receive a roller
carried by the crank fixed to the pedal crank axle. The disc carrying the chain wheel
is so fixed to the frame of the machine in relation to the pedal crank axle, that the
effective length of the pedal crank is gradually increased from the top of the stroke
to mid-stroke and from thence decreased to the bottom of the stroke, the increased
effective length being equal to the distance between the centres of rotation of the
pedal crank axle and chain wheel respectively.
Dated this 10th do of Al 1000
ROBT. E. PHILLIPS, M.I.M.E.,
Consulting Engineer and Patent Agent,
Royal Courts Chambers, 70-72, Chancery Lane, London, W.C.,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Velocipedes.
I, WILLIAM CRAMPIN, of 24, Upper Thames Street, in the City and County of
London, Mechanic, 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 a device for giving increased leverage on the pedal crank
axle, without increasing the throw of the cranks, or varying the radius of the paths
of motion of the pedals, and it has for its object increased power and consequently
a saving of labor in propelling velocipedes.
I attain this object in the manner illustrated in the accompanying drawing in
which Figure 1 is a view in side elevation of my device, and Figure 2 is a view in
plan thereof partly in section. Throughout the figures similar parts are marked
with like letters of reference.
I mount the pedal crank axle A in bearings carried by the frame in the usual
manner, and on each end of the said axle I key cranks B and B₁ both pointing in
the same direction, and not in diametrically opposite directions. On a prolongation
of the pedal crank axle-outside the crank B is loosely mounted another crank B2,
which is made of the same length as the crank B and is adapted-as is the crank B-
at its free end to receive a pedal in the usual manner.
These cranks B¹ and B2
are the driving cranks. The driving chain wheel C instead of being keyed on to the

page_text: pedal crank axle. A is loosely mounted on a disc D fixed to and carried by any
convenient part of the frame X of the machine immediately inside the crank B
and eccentric the pedal crank axle A. I prefer to place balls between the wearing
faces of the disc D and chain wheel C forming a ball bearing and thereby reducing
the friction between these parts. On to the chain wheel C is formed or fixed--on
each side thereof-a crank C each having formed therein a longitudinal slot c the
one adapted to receive a roller b' carried by the crank B' and the other adapted to
receive a rollér 62 carried by the crank B2.
It will be seen that the disc D carrying the chain wheel C is so fixed to the
frame X of the machine in relation to the pedal crank axle A that the effective
lengths of the pedal cranks B and B are gradually increased from the top of the
stroke to mid stroke, and from thence decreased to the bottom of the stroke, the
increased effective length being equal to the distance between the centres of rotation
of the pedal crank axle and chain wheel respectively.
I wish it to be particularly understood that I do not limit myself to the precise
details of construction herein before described and illustrated by the accompanying
drawing, but hold myself at liberty to make such changes and alterations as fairly
come within the spirit and scope of my invention.
I am aware that it is not new to use eccentrics for the purpose of increasing the
leverage of cranks and I therefore do not broadly claim such, but
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1st. The improved device for operating the driving chain wheel of a velocipede,
substantially as and for the purpose set forth.
2nd. In a velocipede, mounting the driving chain wheel loosely on a disc fixed to
and carried by the main frame so that the centre of its rotation is eccentric with the
centre of the pedal crank axle, and communicating motion to the said chain wheel
by means of three cranks mounted on the pedal crank axle, and two cranks mounted
on or carried by the chain wheel, as and for the purpose set forth.
3rd. In a velocipede, the combination with the pedal crank axle, of the crank B
fixed to one end of the axle and adapted to carry one of the pedals; of the crank B₁
fixed near to the other end of the axle and adapted to carry at its free end a
suitable stud pin on which is mounted a roller b'; of the crank B² mounted loosely
on the end of the axle outside the crank B', adapted to carry the other pedal, and
having a suitable stud pin on which is mounted a roller 2; of the disc D fixed to
and carried by the main frame of the machine; of the chain wheel C mounted on the
said disc so that it is free to rotate thereon; and of the cranks or arms ce formed
on or fixed to the said chain wheel and having longitudinal slots c. c to receive the
rollers and 2 carried by the cranks B' and B2 respectively; all combined,
arranged and operating as and for the purpose set forth.
Dated this 10th day of January 1890.
ROBT. ED. PHILLIPS, M.I.M.E., ETC.,
Consulting Engineer & Patent Agent,
Royal Courts Chambers, 70-72, Chancery Lane, London, W.C.,
Agent for the Applicant.