Improvements in or relating to Driving Cranks. for Cycles, Mechanically Propelled Vehicles, and the like.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Driving Cranks. for Cycles,
Mechanically Propelled Vehicles, and the like.
I, WALTER HYSLOP, of 57, Marlborough Street, Seaham Harbour, in the
County of Durham, Accountant, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in the driving cranks of bicycles,
tricycles, and the like, and can also be adapted to mechanically propelled
vehicles. The improvements consist in means for automatically changing the
length of the crank in such a manner that the power or pressure exerted by the
rider (in the case of cycles) will act at the greatest leverage when the crank is
descending.
Two discs or wheels are fixed to the cycle frame one on each side thereof and
are situated between the frame and the cranks. The crank axle passes through
each disc behind its centre, the centres of the axle and discs being preferably
in a horizontal plane. A strap or band encircles each eccentric disc, a suitable
recess being provided in the periphery of each of the discs so as to keen the
These
straps in position and to guide them in their movement on the same.
straps are each connected by means of pins or bolts or by other suitable means
to its respective crank. It is evident that the distance between the crank axle
and its respective strap pin will vary during the revolution of the said crank,
therefore each crank arm is made in two pieces, the outer one of which slides in or
on the inner one to a certain extent. The inner piece of the crank is fixed on the
crank axle. The extreme travel of the outer or sliding portion of the crank will
be twice the throw of the eccentric disc, that is, twice the distance between
the disc centre and the axle centre, and this will be the amount that the leverage
of the crank will vary. The rider when propelling his machine forward will
exert pressure at the long leverage, and the upward resistance to the crank will
act at the short leverage.
By exerting the same power a rider will thus be able with this improved
crank gear to work a machine much higher geared than can be used with the
ordinary crank. "In order to reduce friction, balls or rollers may be arranged
between the straps and the peripheries of the discs, as also in the sliding con-
nections between the segments of the respective crank arms, suitable forms of
grooves or guides in each case being provided.
Instead of straps or bands being arranged on the eccentric discs the pins for
guiding the movable arms of the cranks may have their ends shaped, or they
may be fitted with shaped pieces to work in suitably formed grooves in the
peripheries of the discs; or rollers of the pins may work in grooves in the face
of the discs.
thi 21 day of June 1908
HERBERT HADDAN & Co.,
Agents to Applicant
18, Buckingham Street, Strand, W.C., London,

page_text: Improvements in or relating to Driving Cranks for Cycles,
Mechanically Propelled Vehicles, and the like.
I, WALTER HYSLOP, of 57, Marlborough Street. Seaham Harbour, in the
County of Durham, Accountant, 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 improvements in the driving cranks of bicycles
tricycles and the like and can also be adapted to mechanically propelled
vehicles. The improvements consist in means for automatically changing the
length of the crank in such a manner that the power or pressure exerted by the
rider (in the case of cycles) will act at the greatest leverage when the crank is
descending.
The accompanying drawings illustrate means for automatically changing the
length of a crank consisting of two parts one sliding upon the other. Fig. 1 is
a side elevation, and, Fig. 2 a plan view of the said mechanism. Fig. 3 is a
longitudinal section of the crank and Fig. 4 a cross section on line 4-4 of
Fig. 3, these two last mentioned figures being on a larger scale.
The crank is made in two pieces A, B of which the outer piece encases and
is made to slide upon the inner piece in the direction of its length. The outer
piece A which may be formed of a three sided part a and a cover part a¹ secured
thereto by screws a² is solid at one end where it is provided with a hole afor
attachment of the pedal pin and is open at the other end at a. At a suitable
place, near the open end at by preference, the outer part A carries the axles
of rollers as for the frictionless guiding of the inner part B which is preferably
grooved at b b in the direction of its length to accommodate the said rollers a³.
At a suitable place on the inner part preferably near the end thereof protrud-
ing into part A are also the axles of other rollers which similarly guide
the outer part A by means of grooves as a in the sides of part A. In part B
is a prismatic hole 62 by means of which the part B is fastened on the crank
shaft C, and in the part A is a slot a allowing the part A to slide without
hindrance from the said axle C.
It will be obvious that the crank so made may be extended and contracted
radially from the axle C and that if means are provided for automatically
extending the crank shaft at the proper time, its leverage will be increased.
On the part A is a projecting pin 1 which may have an antifriction roller on it
in the well known manner, and surrounding the axle C is a cam or excentric
course giving to the pin D the necessary outward and inward movements.
In the drawing there are illustrated two circular rings E forming circular
ring grooves for the pins D respectively of the two pedal cranks. A convenient
means of securing these rings excentrically of the axis of the pedal crank shaft,
consists of the lugs e e e e¹ of which the three lugs e e e can be fastened by
bolts to strengthening pieces brazed upon the cycle frame tubes F F1 F2
respectively, and the lug e¹ can be fastened to the corresponding lug e of the
other ring E by a cross bar e2 and nuts e³ e³. I do not however confine myself
to this method of securing the ring that guides the pin D since it is obvious
that various means can be used for this purpose both upon cycle frames or other
places where my improved automatically extensible and contractible crank may
be used.

page_text: Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:
1. A driving crank for cycles, mechanically propelled vehicles and the like
consisting of parts one sliding upon another so as to be extensible and con-
tractible in the line of said crank, in combination with means for automatically
increasing the length and decreasing the same for the purpose set forth.
2. A driving crank for cycles, mechanically propelled vehicles and the like
constructed substantially as herein described for the purpose set forth.
3. The combination of an extensible driving crank formed of sliding parts as
described with a grooved ring fixed excentrically of the axle forming in effect
a cam engaging a projection of one of the parts of the crank to automatically
change the length of the same as it moves on its axis.
Dated this 2nd day of March 1899.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, W.C., London,
Agents to Applicant.