Improved Crank Mechanism for Cycles and the like.
Year: 1898

page_text: Date of Application, 30th Nov., 1898
Improved Crank Mechanism for Cycles and the like.
ALFRED KERFOOT, Fitter, Main Street, Cappoquin, County Waterford, Ireland,
and JOHN JAMES KERR, Patternmaker, Mass Lane, Cappoquin, County Water-
ford, Ireland, do hereby declare the nature of this invention to be as follows:-
A method, whereby that part of the crank, to which the pedal is attached;
is caused to slide from the crank centre in the downward throw, thereby gaining
more leverage. This action is caused by means of a cam, or an eccentric, attached
to the bottom bracket, or, by a spring contained in the crank.
In the case where a spring is used that part of the crank to which the pedal
is attached, can slide in that part of the crank which is fixed to the crank centre,
but is held back by a spiral spring, but when pressure is brought to bear on
the pedal; the spring is compressed, by the pedal end of crank, sliding from
crank centre; but resumes its former position when pressure ceases.
Dated this 3rd day of January 1899.
Signed,
ALFRED KERFOOT,
JOHN JAMES KERR.
ALFRED KERFOOT, Fitter, 104, Butt's Bridge, Leigh, Lancashire, and JOHN
JAMES KERR, Patternmaker, 33, Manchester Road, Leigh, Lancashire, "late of'
Main Street, Cappoquin, County Waterford, Ireland, and Mass Lane, Cappoquin,
County Waterford, Ireland, respectively, 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:-
A method whereby that part of the crank to which the pedal is attached, is
caused to slide from the crank centre, in the downward stroke thereby gaining
more leverage.
The invention as shewn in the accompanying drawings, is, as applied to a
cycle. The crank is a compound crank, being composed of two parts. One part
is a casting of such a shape so as to be securely attached to the crank axle, and
also shaped at one end to contain rollers, in which the other part of the crank,
(being the pedal end part) reciprocates; and shaped at the other end to form
slots for the rollers on the tee piece to run in the said tee piece to be securely
attached to the pedal part of crank; the said rollers and said tee piece to prevent
the pedal part of crank from twisting. The tee piece aforesaid also has a pro-
jection on the inner end to take a roller to run in the cam.

page_text: The two cams have a race cast or cut in a somewhat heart shaped fashion,
and are so shaped that the pedal part of crank during the greater portion of
the downward stroke does not slide; therefore the pedal in the downward stroke
will describe an arc, during the time that pressure is brought to bear on said
pedal for propelling the cycle. The cams can be secured to the frame with bolts,
or in any manner that will properly secure them to the frame. All rollers can
be made to run on balls so as to be adjustable. To more fully describe the
invention reference is made to the accompanying drawings, in which like letters,
represent similar parts:-
Fig. 1, is elevation shewing crank at its longest length.
Fig. 2, is cross section shewing details and connections.
Fig. 3, is elevation shewing crank at its shortest length.
Fig. 4, is enlarged section through line R S, shewing crank rollers.
Fig. 5, is enlarged section through line T U, shewing tee piece and rollers.
Fig. 6, is elevation of cam.
A is the cam. B is the race. C the crank axle. D pedal end of crank.
E crank axle end of crank. F grooved rollers. G tee piece rollers. G¹ tee
piece. H cam rollers. I chain wheel. J dotted line shewing sweep of pedal.
K bolts to fasten cams to frame.
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. In pedal cranks of cycles the combination of a cam having a heart shaped
or approximately heart shaped race, a crank sliding in the direction of its length,
and a roller attached to the crank which roller travels in the race and actuates
the crank for the purposes described and substantially as illustrated.
2. In a cycle crank with the throw actuated by a cam with a heart shaped or
approximately heart shaped race, the said race being of such a shape that the
throw of the crank, does not vary but describes an arc radial with the crank axle
centre in the downward stroke.
Dated this 29th day of August 1899.