IMPROVEMENTS IN THE FORKS OF BICYCLES AND OTHER VELOCIPEDES, AND IN THE MANUFACTURE OF THE SAME."
Year: 1881

page_text: LETTERS PATENT to Samuel Armstrong, of Birmingham, in the County of
Warwick, for an Invention of "IMPROVEMENTS IN THE FORKS OF BICYCLES
AND OTHER VELOCIPEDES, AND IN THE MANUFACTURE OF THE SAME."
PROVISIONAL SPECIFICATION left by the said Samuel Armstrong at the
Office of the Commissioners of Patents on the 7th November 1881.
SAMUEL ARMSTRONG, of Birmingham, in the County of Warwick. IMPROVE-
MENTS IN THE FORKS OF BICYCLES AND OTHER VELOCIPEDES, AND IN THE
MANUFACTURE OF THE SAME."
"
My Invention has for its object improvements in the forks of bicycles and other
velocipedes and in the manufacture of the same, by which I am enabled to produce
a lighter and stronger fork which is also more accurate in its important parts.
I am also enabled by my improved mode of manufacture to produce these forks at
cheaper rate than hitherto.
The back forks of bicycles have hitherto been generally made as follows:-
1st. A blank is cut from a sheet of metal.
2nd. The sides are fullered or hollowed.
3rd. The crown is raised by a series of processes or blows.
4th. Making the junction shank which properly forms a part of the back fork.
5th. Brazing the junction shank in the crown of the back fork.
:-
Forks so made have the following disadvantages:-
1st. They are often weak around the base of the crown because the dies have a
tendency to draw the sheet metal out thinner during the process.
2nd. The pivot ends are often out of truth with each other when finished
because the centre has to be raised after the legs are shaped.
3rd. The junction shank is very liable to work loose, which is most inconvenient
and dangerous.
Now according to my Invention these weaknesses are almost entirely avoided in
the following manner :-
First. I take a solid bar of metal of almost any section, but preferably of an oblong
section, which I hammer down in suitable dies with the legs perfectly opened out

page_text: .
until the forging is complete in such a manner that a considerable substance of
metal is forced down into the female or lower die at the crown or centre part by
the upper or male die where it is formed into the desired shape, and by the same
process and at the same time the legs of the fork are worked to the desired shape
and section. The legs of the fork are then bent up into the desired position, and
from the fact that they have been worked out to section in a horizontal or nearly
horizontal position, both ends of the legs bear the proper relation as regards
distance to the crown or junction piece.
The cross section of the several parts of my forks may be thus much more easily
varied when made by my new process, and the waste of material is less than in the
case of stamping from sheet metal, and the shoulder or base of the crown is more
homogeneous and less liable to crack. But perhaps the greatest advantage is the
fact that by my improvements I am enabled to form the junction piece at the top
of the crown at the same time in one process and in one piece with the fork, which
could not be commercially done by the old method. All my forks too, are exact
duplicates one of the other, which is no small inatter.
Though I have only explained my Invention as applied to the back fork of a
bicycle, it will be evident that a similar fork might be so made for any other
velocipede.

page_text: by the said Samuel Armstrong in the Great Seal Patent Office on the
6th May 1882.
SAMUEL ARMSTRONG, of Birmingham, in the County of Warwick.
"IMPROVE-
MENTS IN THE FORKS OF BICYCLES AND OTHER VELOCIPEDES AND IN THE
MANUFACTURE OF THE SAME."
My Invention has for its object improvements in the forks of bicycles and other
velocipedes and in the manufacture of the same, by which I am enabled to produco
a lighter and stronger fork which is also more accurate in its important parts. I am
also enabled by my improved mode of manufacture to produce these forks at a
cheaper rate than hitherto.
The back forks of bicycles have hitherto been generally made as follows:-
1st. A blank is cut from a sheet of metal.
2nd. The sides are fullered or hollowed.
3rd. The crown is raised by a series of processes or blows.
4th. Making the junction shank which properly forms a part of the back fork.
5th. Brazing the junction shank into the crown of the back fork.
Forks so made have the following disadvantages :—
1st. They are often weak around the base of the crown because the dies have a
tendency to draw the sheet metal out thinner during the process.
2nd. The pivot ends are often out of truth with each other when bent up
because the centre has to be raised after the legs are shaped.
3rd. The junction shank is very liable to work loose, which is most inconvenient
and dangerous.
Now according to my Invention these weaknesses are almost entirely avoided
in the following manner :-
First. I take a solid bar of metal of almost any section, but preferably of oblong
section, which I hammer down in suitable dies with the legs opened out until the
forging is complete in such a manner that a considerable substance of metal is
forced down into the female or lower die or upper die at the crown or centre part
by the upper or male die where it is formed into the desired shape, and by the
same process and at the same time the legs of the fork are worked to the desired
shape and section. The legs of the fork are then bent up into the desired position
and from the fact that they have been worked out to section in a horizontal or
nearly horizontal position, both ends of the legs bear the proper relation as regards
distance to the crown or junction piece.
The cross section of the several parts of my forks may be thus much more easily
varied when made by my new process, and the waste of material is less than in the
case of stamping from sheet metal, and the shoulder or base of the crown is more
hoinogeneous and less liable to crack. But perhaps the greatest advantage is the
fact that by my improvements I am enabled to form the junction piece at the top
of the crown at the same time in one process and in one piece with the fork, which
could not be commercially done by the old method. All my forks too are exact
duplicates one of the other, which is no small matter.
Though I have only explained my Invention as applied to the back fork of a
bicycle it will be evident that a similar fork might be so made for any other
velocipede.
I will now explain my Invention by the assistance of the accompanying Sheet of
Drawings.
The usual mode of making the back forks of bicycles is illustrated by Figure 4,
where A is the junction shank which is brazed or otherwise fastened into the
fork B. The fork B is usually made as before described from sheet metal.

page_text: Figure 1 represents the solid bar of metal roughly bent up. The view shown is
just half the length, and the section might be of almost any kind which contained
enough, metal to make the fork, but, say, 13 inches wide by inch thick.
This bent bar is then placed upon the bottom die D, D, D, and is hammered out
by the top die E, E, half of which is only shown until the desired shape is obtained,
as seen in section at h, h. h, and in side elevation at k, k, k. It will be noticed
that the fork is forged in a partly horizontal position, i.e., with the legs of the
fork bent at W, W, which is essential, as without this bend practical success cannot
be attained. I then straighten out the legs, as shown by Figure 2 front elevation
and Figure 3 side elevation. Thus it will be clearly seen that my forks are
provided with a suitable provision M for joining to the backbone without brazing
or otherwise joining the separate junction piece A, as shown by Figure 4.
I am thus enabled to avoid any liability of the part A working loose, and the
crown of the fork or part n is stronger, than when joined up separately. There is
also the further advantage in making forks according to my Invention that I am
enabled without difficulty to vary the section or thickness at various parts of the
length, such as for instance the part 1 may be thinner than part 2, and part 2
may be thinner than part 3. There is also less strain upon the metal by my process
than when raised from sheet metal, because I ain enabled, to keep a sufficiency of
substance at the centre to gradually work down into the upper part of the legs
which could not be done with sheet metal.
Having now described my said Invention of improvements in the forks of bicycles
and other velocipedes,, and in the manufacture of the same, I would have it
understood that what I claim as my Invention is,―
The-new-solid fork, as shown by Figures 2 and 3, made-substantially_in_the
manner and for the purpose herein set forth with modifications of the same.
In witness whereof, I, the said Samuel Armstrong, have hereunto set my
hand and seal, this Fourth day of May, in the year of our Lord One
thousand eight hundred and eighty two.
SANTIET
ADSTRONG