Improvements in connection with the Forging of Pedal Cranks for Cycles.
Year: 1894

page_text: Date of Application, 1st Mar., 1894
Complete Specification Left, 1st Jan., 1395-Accepted, 2nd Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in connection with the Forging of Pedal Cranks
for Cycles.
I, HENRY PATTERSON BOYD, of Manor Cottage, Bittern Road, Southampton,
in the County of Hampshire, Engineer do hereby declare the nature of this
invention to be as follows:-
My invention relates to improvements in the construction or manufacture of
pedal cranks, as used for the propulsion of bicycles, tricycles and similar manumotive
machines, and has for its object to cheapen the cost of manufacture by the
employment of mechanical means for effecting that which has hitherto been done by
hand, and by a system of forging to produce cranks of greater strength relatively to
their dimensions, and the weight of metal employed, than has been possible by the
systems of casting these, or punching or pressing them from sheet metal as
hitherto.
I carry my invention into effect by first producing, from any suitable metal
or alloy of metals, or phosphor bronze, by casting or otherwise, a crank blank, the
length of which, in this condition, may be one or more inches less than the length
it is desired the finished crank shall be, and having the shank and eye already
formed thereon.
The said blank would then be heated and placed between a pair of steel dies, in
each of which a tapered recess or recesses is or are formed, preferably simi circular
or thereabouts in cross section, and in such a manner that the recess or recesses in
the one, coincide with that or those in the other, when the said dies are brought
together face to face, the length of the said recess or recesses being such as not to
exceed the distance between the shank and eye of the heated blank. One of said
dies would be fixed or held stationery, preferably the bottom one, while the other
would be operated by some suitable power, such for instance as a mechanical
hammer, actuated by steam, hydraulic or other means, and the said moving die
would be so formed that this may be easily connected to the said hammer head,
constructed to receive the same, such attachment being effected by the employment
of cotters, pins, screws or other suitable means.
The cross sectional diameter of the heated blank, would, in all cases be greater
than the cross sectional diameter of the tapered recess or recesses formed by the
junction of the two dies, and I may arrange (where more than one recess is formed
n each die) that the said recesses may be of different diameters so that the heated
blank may be first operated upon by the larger recess and afterwards by the
maller, the operation being, that by rotating the heated blank to and fro between
he meeting of the dies the cross sectional diameter of the blank would be gradually
essened while its length would be extended, and by this means the molecules of the
netal would be pressed closer together, and the strength of the crank be enhanced
hereby, and I find in practice that when the said crank has been sufficiently
longated by this means, this upon leaving the dies is perfectly smooth and needs
ut little filing except at the shank and eye to render it in a finished condition.
Dated this lot doz of Mauch 1804
GEO. THOS. HYDE,
4, Moorfields, Fore Street, London, E.C., Agent for the Applicant.

page_text: r
Improvements in connection with the Forging of Pedal Cranks
for Cycles.
I, HENRY PATTERSON BOYD, of Manor Cottage, Bittern Road, Southampton,
in the County of Hampshire, Engineer 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 improvements in the construction or manufacture of
pedal cranks as used for the propulsion of bicycles, tricycles, and similar manumotive
imachines, and has for its object, to cheapen the cost of manufacture, by the
employment of mechanical means for forging the said cranks instead of effecting
this by hand as hitherto, and by this means to produce cranks of greater strength
relatively to their dimensions, and the weight of metal employed, than has
been possible by casting these, or punching or pressing them from sheet metal
heretofore.
In order that my invention and the manner of carrying the same into effect may
be clearly understood reference is herein made to the accompanying sheet of
drawings, of which,
Fig. 1 is a view of a crank first produced by casting or other means before being
treated according to my invention.
Fig. 2 is a view of same in a finished state, after being treated according to my
invention.
Figs. 3 and 4 are face views of the form of die or block I employ in converting
Fig. 1 into Fig. 2 as hereinafter explained.
Fig. 5 and 6 are end views of Figs. 3 and 4 in pairs, as they would appear if
viewed from bottom to top.
Fig. 7 is a face view of a triple grooved die or block such, as I may employ as
hereinafter explained.
Fig. 8 is an end view of a pair of such dies or blocks as Fig. 7, as they would
appear when viewed from bottom to top.
1 carry my invention into effect by first producing from any suitable metal, or
alloy of metals, such for instance as those known as "Bulls metal," "bell metal,"
or phosphor bronze, by casting or otherwise, a crank blank such as A Fig. 1, the
length of which, when in this condition, would, by preference, be one or more inches
less than the length it is desired the finished crank shall be, and having the usual
shank and eye already formed therein, and this when heated I subject to the
following treatment:
I cast or otherwise produce from suitable metal, preferably hardened steel,
a pair or any number of pairs of dies or blocks C, D, such as Fig. 3, the
length of which would be, preferably, not in excess of the distance between the
shank and eye of Fig. 1, and in each of these I form a tapered recess or groove B,
in such a manner, that that in C perfectly coincides or registers with that in D
when C and D are placed together face to face, as indicated by Fig. 5. I prefer
that each of the said recesses or grooves shall be slightly less than a perfect
semicircle, that is to say, if a distance equal to 16 or 3 of an inch separates the
faces of C and D, their combined recesses or grooves would form a perfect circle,
slightly less in diameter than that of the blank A, Fig. 1.
One of said dies or blocks would be held stationary, preferably the lower one D,
while the other would be operated by some suitable power, such for instance as a
mechanical hammer, actuated by steam, hydraulic or foot power, and to effect this
the lower die D may be provided with a dovetail or other shaped tongue E, capable
of fitting into a like shaped recess in the base of the hammer, while a like or other

page_text: shaped tongue F may be formed upon the upper die C, engaging with a like shaped
recess in the hammer head, and both may be retained in position by the means of
cotters, pius, screws or their equivalents.
The heated blank A, held by suitable pliers, would be laid within the recess or
groove in D, when the upper die C would, by whatever power employed, be caused
to descend with force upon A, and by reason of the diameter of this being in excess
of the diameter of the said recesses or grooves B, would, if rotated to and fro
between the meeting dies C and D, be gradually reduced in thickness and extended
in length, until this became as at Fig. 2, or the required length that the crank
should be, and by this means the molecules of the metal A would be pressed closer
together, and the strength of the crank be enhanced thereby.
1 may find it convenient, or where the pair of dies Figs. 3 and 5 do not reduce
the diameter of the blank A to that required, to employ a second pair of dies,
having a tapered groove or recess B of lesser diameter, as shewn at Figs. 4 and 6,
which may be connected to the same hammer head and base, and in the same
manner as the first pair, so as to operate simultaneously therewith, which provides,
that when then the blank A has been sufficiently treated by the first pair of dies,
it may be transferred to, and be finished by the second pair, or a third pair having
still narrower recesses or grooves B if required, which may if practicable, be fitted
to the same hammer and base.
Or I may employ a pair of dies CD in which three grooves or tapered recesses B
are formed of different diameters, as at Figs. 7 and 8, so that the blank A may be
first treated and partly forged by the widest or left hand groove, and then by the
next widest or right hand groove, and ultimately be transferred to and finished by
the narrowest or centre groove, which may if necessary be longer than the others
as shewn.
I find in practice, that when the blank A has been forged in this manner, and
sufficiently elongated to produce the pedal crank Fig. 2, that this, upon leaving the
dies, is perfectly smooth in every part except the shank and eye, which require
slight treatment with the file or emery wheel to render the whole in perfect
condition for mounting upon the machine, or to be enamelled or electro plated
if desired.
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 herein described method of forging pedal cranks for cycles, from any
suitable metal or alloy of metals, by the means of a pair or any number of pairs of
dies, such as C, D, each provided with a tapered recess or recesses or groove or
grooves such as B, and tongues or extensions such as E, F, for attaching them to
the head and base of any suitable type of mechanical hammer, connected combined
and operating substantially as and for the purposes herein described and shewn.
Dated this 31st day of December 1894.
GEO. THOS. HYDE,
1, Broad Street Buildings, London, E.C., Agent for the Applicant.