An Improved Crank for Velocipedes.
Year: 1894

page_text: Date of Application, 8th Aug., 1894
Complete Specification Left, 8th May, 1895-Accepted, 15th June, 1895
An Improved Crank for Velocipedes.
AUGUSTINE CAMPBELL DAVISON of 531 Holloway Road in the County of
London Civil Engineer, and HARRY LUCAS of Little King Street in the City of
Birmingham, Lamp Manufacturer do hereby declare the nature of this invention
to be as follows:-
The object of this invention is to make an improved built up hollow crank for
velocipedes, which by the arrangement of and description of metal it is possible to
use, shall be stronger weight for weight than any solid crank or hollow crank as
previously constructed, and which shall not depend for its strength upon the brass
used in soldering it.
We are aware that hollow cranks have been made of ordinary weldless steel
tube, but such cranks owing to the softness of the metal necessary to enable it to
be drawn into tube, are not so strong as a solid crank of equal weight made of
harder steel; and we are also aware that cranks have been formed of tubes built
up with sheet steel coiled with solid bosses placed over the ends of the said tube
and brazed on but such cranks obviously depend entirely upon the strength of the
brass attaching the solid bosses in some positions of the crank.
To avoid these defects we construct the crank as follows-We make a rect-
angular tube of thin but very strong sheet steel bent round a form and lapped over
and brazed along the lapped part. We make this tube of such width & thickness
at the crauk spindle end that two holes may be drilled through it, the one through
the sides for the crank spindle and the other at right angles to it through the top
and bottom for the attaching cotter, leaving a fair margin of metal round them.
We reduce the dimensions of the tube towards the pedal end, tapering it gradually
to the point of attachment of the pedal pin where it may be just wide enough to
allow a hole to be drilled through the sides for the attachment of the pedal pin
leaving a fair margin of metal round it.
Into each end of the tube as above described and preferably before the holes
have been drilled we drive & braze in a solid end, and then drill the holes right
through both the tube and the said solid end at once; or instead of driving the
solid ends into the tube and drilling them we may use tubular pieces passed through
from side to side and top to bottom for attaching the crank to the spindle or to the
pedal pin and thereby save a little in weight.
By this construction both the attaching cotter at the crank spindle end and the
pedal pin at the other end pass through and bear on the solid metal of the tube
and do not depend entirely upon the brazing of the ends for their strength of
attachment.
In order to keep the width and thickness of the crank small for appearance sake
we prefer to drive on a collar of weldless steel tube over the built up tube at the
spindle end and braze it on, so as to leave a fair margin of metal where pierced
by the holes without making the tube so large, but if the crank be made of
sufficient width and thickness such collar is not absolutely essential to the
construction.
Dated this the 7th day of August 1894.
AUGUSTINE CAMPBELL DAVISON.
HARRY LUCAS.

page_text: AUGUSTINE CAMPBELL DAVISON of 531 Holloway Road in the County of
London Civil Engineer, and HARRY LUCAS of Little King Street in the City of
Birmingham Lamp 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 :-
The object of this invention is to make an improved built up hollow crank for
velocipedes which by the arrangement of & description of metal it is possible to
use shall be stronger weight for weight than any solid crank or hollow crank as
previously constructed and which shall not depend for its strength upon the brass
used in soldering it.
We are aware that hollow cranks have been made of ordinary weldless steel tube
but such cranks owing to the softness of the metal necessary to enable it to be
drawn into tube are not so strong as a solid crank of equal weight made of harder
steel, & we are also aware that cranks have been formed of tubes built up with
sheet steel coiled, with solid bosses placed over the ends of the said tube & brazed
on but such cranks obviously depend entirely upon the strength of the brass
attaching the solid boss in some positions of the crank.
To avoid these defects we construct the crank as follows-We make a rect
angular tube of thin but very strong sheet steel bent round a form & lapped over
& brazed along the lapped part. We make this tube of such width & thickness at
the crank spindle end that two holes may be drilled through it, one through the
sides for the crank spindle & the other at right angles to it through the top &
bottom for the attaching cotter leaving a fair margin of metal round them.
reduce the dimensions of the tube towards the pedal end, tapering it gradually to
the point of attachment of the pedal pin where it may be just wide enough to
allow a hole to be drilled through the sides for the attachment of the pedal pin,
leaving a fair margin of metal round it.
We
Into each end of the tube as above described and preferably before the holes
have been drilled we drive & braze in a solid end & then drill the holes right
through both the tube and the solid end at once.
But instead of driving the sclid ends into the tube & drilling them we may use
tubular pieces passed through from side to side & from top to bottom for attaching
the crank to the spindle or to the pedal pin & thereby save a little in weight.
By this construction both the attaching cotter at the crank spindle end & the
pedal pin at the other end pass through & bear on the solid metal of the tube
and do not depend entirely upon the brazing of the ends for their strength of
attachment.
In order to keep the width & thickness of the crank small for appearance sake
we prefer to drive on a collar of weldless steel tube over the built up tube at the
spindle end & braze it on so as to leave a fair margin of netal where pierced by
the holes without making the tube so large, but if the crank be made of sufficient
width & thickness such collar is not absolutely essential to the construction.
The invention is more particularly described by the aid of the accompanying
drawings.
In all the figures like parts are indicated by similar letters of reference.
Figure 1 is a view in longitudinal section through the crank.
Figure 2 is a view in plan of the crank & Figure 3 is a section through Figure 1
on the line e. f.
The rectangular tube A is made from sheet steel, preferably of high grade
crucible cast steel, and of any desired thickness.
This sheet steel is bent round a form to the section shown in Figure 3 & brazed

page_text: along the joint. The rectangular tube is made of such dimensions at the end C
that the two holes one for the spindle & the other for the cotter D may be drilled
through it at right angles for attaching it to the spindle leaving a fair margin of
metal round them.
The dimensions of the rectangular tube may be reduced towards the pedal end E
where it may be just wide enough to allow a hole to be drilled through the sides
for the attachment of the pedal pin, leaving a fair margin of metal round
the hole.
Into the end C of the beforementioned tube & preferably before the holes are
drilled we drive the solid end B & braze it in. But instead of the solid end we
may drive two short pieces of tube the one for the cotter & the other for the
spindle & thereby save a little in weight.
Into the small end we drive a solid piece E but this is only to prevent that end
of the tube being squeezed out of shape by tightening the pedal pin.
By the before described method of construction we get the cotter D at the
spindle end to pass through & bear on the solid metal A composing the crank &
similarly the pedal pin at the other end bears on the solid metal, and the strength
of the crank does not depend entirely upon the brazing of the ends.
In order to keep the crank small for appearance sake we prefer to drive on a
collar C preferably of weldless steel tube over the built up tube at the spindle end
& braze it on so as to give a larger margin of metal round the holes without
making the tube A so large, but if the crank be made of sufficient width &
thickness such collar is not absolutely necessary.
Having now particularly described & ascertained the nature of our said inven-
sion & in what manner the same is to be performed we declare that what we
claim is
1. A built up crank for velocipedes consisting of a brazed or otherwise joined
rectangular tube with solid ends placed within it, substantially as described.
2. A built up crank for velocipedes consisting of a brazed or otherwise joined
rectangular tube with solid ends placed within it & with a collar outside at one or
both ends.
3. The improvements in the construction of hollow cranks substantially as
described.
Dated this 7th day of May 1895.
AUGUSTINE CAMPBELL DAVISON.
HARRY LUCAS.