IMPROVEMENTS IN MEANS OR APPARATUS TO BE EMPLOYED IN THE MANU- An Canning AD VULCANITE OR OTHER ANALOGOUS MATERIAL
Year: 1874

page_text: LETTERS PATENT to George Henry Roberts, of River Street, Devon's
Road, Bow, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN MEANS OR APPARATUS TO BE EMPLOYED IN THE MANU-
An Canning AD VULCANITE OR OTHER ANALOGOUS MATERIAL."
Sealed the 28th August 1874, and dated the 24th June 1874.
PROVISIONAL SPECIFICATION left by the said George Henry Roberts
at the Office of the Commissioners of Patents, with his Petition,
on the 24th June 1874.
I, GEORGE HENRY ROBERTS, of River Street, Devon's Road, Bow,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MEANS OR APPARATUS TO BE EMPLOYED IN
THE MANUFACTURE OF SCREWS OF VULCANITE OR OTHER ANALOGOUS MATERIAL," to
be
as follows: :-
↑ . I
The Invention has for its object improvements in means or apparatus
to be employed in the manufacture of screws of vulcanite or other
analogous material. For this purpose I employ a mould formed of a
number of pieces or cores of metal to form the threads of the screw,

page_text: each piece or core being in the form of the space between two adjacent
threads or worms, and having a projecting rim or flange running along
one side thereof. These pieces or cores are cut off at one end at a
right angle to the direction of the worms or threads, and at the other
end at a right angle to the axis of the screw. These pieces or cores
are arranged inside a cylindrical mould box in such manner as to form
a complete mould of the screw required; they fit against each other and
are received at their lower ends on a piece of metal shaped to fit. The
top and bottom of the cylinder are formed in separate pieces capable
with the cylinder of being readily put together and taken apart. The
bottom of the cylinder is formed with a projection to fit and pass a
little way into the cylinder, and has formed in the centre thereof a
small projection, which serves to indicate the centre of the desired
screw, to assist in centreing it in a lathe for drilling and otherwise
working it. The top of the cylinder is formed with an annular pro-
jection of the shape required for the boss and with a projection to form
the centre of the screw.
When the parts are all put together, with the exception of the top,
the rubber or composition to form the screw. is placed in the mould in
bulk sufficient to let it stand somewhat above the mould; the top of
the cylinder is then placed on the top of the rubber or other analogous
material, when it is forced down, preferably by screw or hydraulic
pressure, so as to force the rubber or other material into the spaces
between the cores or separate pieces to form the screw. The mould
with the screw therein is then submitted to heat for a sufficient time to
cure the screw, after which the top and bottom of the cylinder aro
removed and the screw with the cores pushed out of the mould, after
which each separate core is screwed out of the screw.
According to my Invention I form these cores of tin or other readily
fusible metal capable of withstanding the heat required to "
"
cure the
screws, and these cores are cast in moulds of the form required, but if
desired they may be made of other metal.
If a hollow screw is required, I in some cases fill the mould with
rubber or other material and then cause a central plunger to descend,
which in addition to forming the hollow required also at the same time
forces the material into the spaces of the mould.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Henry Roberts in the Great Seal Patent
Office on the 23rd December 1874..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HENRY ROBERTS, of River Street, Devon's Road, Bow, in the County
of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of June, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-eighth year of Her reign, did,. for Herself, Her heirs and
successors, give and grant unto me, the said George Henry Roberts,
Her special license that I, the said George Henry Roberts, my exe-
cutors, administrators, and assigns, or such others as I, the said George
Henry Roberts, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times.
thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for " 'IMPROVEMENTS IN MEANS OR APPARATUS TO BE EMPLOYED IN
THE MANUFACTURE OF SCREWS OF VULCANITE OR OTHER ANALOGOUS MATERIAL,
upon the condition (amongst others) that I, the said George Henry
Roberts, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
"
NOW KNOW YE, that I, the said George Henry Roberts, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained.
in and by the following statement thereof, that is to say :-
The Invention has for its object improvements in means or apparatus
to be employed in the manufacture of screws of vulcanite or other
analogous material. For this purpose I employ a mould formed of a
number of pieces, cores, or spiral segments of metal to form the
threads of the screw, each piece, core, or spiral segment being in the

page_text: orm of the space between two adjacent threads or worms and having
a projecting rim or flange running along one side thereof. These
pieces, cores, or spiral segments are cut off at one end at a right angle
to the direction of the worms or threads, and at the other end at a
right angle to the axis of the screw. These pieces, cores, or spiral
segments are arranged inside a cylindrical mould box in such manner
as to form a complete mould of the screw required; they fit against
each other, and are received at their lower ends on a piece of metal
shaped to fit. The top and bottom of the cylinder are formed in
separate pieces capable with the cylinder of being readily put together
and taken apart. One end of the cylinder is formed with a projection
to fit and pass a little way into the cylinder, and has formed in the
centre thereof a small projection, which serves to indicate the centre
of the desired screw; to assist in centreing it in a lathe for drilling and
otherwise working it. The other end of the cylinder is formed with
an annular projection of the shape required for the boss and with a
projection to form the centre of the screw.
When the parts are all put together, with the exception of the top,
the rubber or composition to form the screw is placed in the mould in
bulk sufficient to let it stand somewhat above the mould; the top of
the cylinder is then placed on the top of the rubber or other analogous
material, when it is forced down, preferably by screw or hydraulic
pressure, so as to force the rubber or other material into the spaces
between the separate pieces, cores, or spiral segments to form the
screw. The mould with the screw therein is then submitted to heat
for a sufficient time to cure the screw, after which the top and bottom
of the cylinder are removed and the screw with the cores or spiral
segments pushed out of the mould box, after which each separate core
or spiral segment is screwed out of the screw.
According to my Invention I form these cores or spiral segments of
tin or other readily fusible metal capable of withstanding the heat
required to "cure" the screws, and these cores or spiral segments are
cast in moulds of the form required, but if desired they may be made
of other metal.
If a hollow screw is required, I in some cases fill the mould with
rubber or other material and then cause a central plunger to descend,
which in addition to forming the hollow required, also at the same time
'forces the material into the spaces of thic mould;

page_text: Figure 1 is a vertical section of a mould box and parts connected
therewith, constructed according to my Invention, but showing only
one of the spiral segments or cores in position; Figure 2 is a section of
the mould box on the line 1, 1, of Figure 1, with all the spiral segments
or cores removed therefrom.
Figure 3 is a plan of the mould box with the cover removed, but
showing the spiral segments or cores in position.
Figure 4 is a cross section of one of the spiral segments or cores
taken at right angles thereto; and Figures 5 and 6 are respectively a
plan and edge view of support for the spiral segments or cores.
a are the spiral segments or cores of metal, of which as many are
employed as there are threads to the screw. These spiral segments, or
cores a are cachi formed of a corresponding shape to that of the space
between two adjacent threads or worms, and they are each provided
with a projecting rim, web, or flange a² running along one side thereof.
These spiral segments or cores are cut off at the end a² at or about a
right angle to the direction of the worms or threads, and at the other
end a³ at a right angle to the axis of the screw. These spiral segments
or cores a are arranged inside a cylindrical mould box 6 in such
manner as to form a complete mould of the screw required; they fit
against each other at their rims, webs, or flanges a¹, as shown in plan
at Figure 3, and are received at their lower ends on a piece of metal c:
shaped to fit. The top 6¹ and bottom 62 of the cylinder are formed in
separate pieces to fit the cylinder, with plain cylindrical surfaces
capable of being readily placed in position and taken apart from the
cylinder. The top 6₁ of the cylinder is formed with a projection to fit
and pass a little way into the cylinder, and has formed at the centre
thereof a small projection 6³, which serves to form a depression in the
desired screw, and thereby indicate the centre thereof to assist in
centreing it in a lathe for drilling and otherwise working it. The
bottom of the cylinder is formed with an annular projection 6 of

page_text: the shape required for the boss of the screw, and with a projection 65
to indicate the centre of the screw. The piece c fits around the
projection 6 and occupies the space between it and the cylinder b.
When the parts are all put together, with the exception of the top b',
the composition of caoutchouc or other analogous composition to form
the screw is placed in the mould in quantity sufficient to let it stand
somewhat above the mould 6; the top b' is then placed on the top of the
composition of caoutchouc or other analogous material, when it is forced
down, preferably by screw or hydraulic pressure, so as to force the
material into the spaces between the spiral segments or cores a to form
the screw.
The mould with the screw therein is then submitted to
heat for a sufficient time to " cure the material forming the screw,
after which the top 6¹ and bottom b² are removed and the screw with
the cores a pushed out of the cylinder or mould box, after which each
separate core a is pushed or screwed out of the screw.
The screw
may then be finished and mounted on a stud or axis as will be well
understood.
"
According to my Invention I form the spiral segments or cores a
of tin or other readily fusible metal capable of withstanding the heat
required to cure the screws, and these cores are cast in metal moulds
of the form required, but if desired the cores a may be otherwise made
of other metal or alloy.
If a hollow screw is required the mould may be filled with caoutchouc
or other analogous composition, and then a central plunger may be
caused to descend, which in addition to forming the hollow required,
also at the same time forces the material into the spaces of the mould.
Having thus described the nature of my said Invention, and the
mode in which I carry the same into effect, I would here remark that
I am aware that spiral segments a have before been employed in the
manufacture of similar screws, but in such case the spiral segments
were formed without the rims, webs, or flanges a¹ and were kept in
position by means of end pieces, through which screws were passed,
one into each spiral segment, and such spiral segments were formed at
their ends, so that when in position those parts met together, and
around the outer sides of such segments portions of screw threads were
formed, so that they might together form a complete screw on to which
caps were screwed, such caps meeting together and completing the shell

page_text: of the mould; I do not therefore claim the employment of spiral
segments generally for the purpose described, but what I claim is,―
First. The employment in the manufacture of screws of vulcanite or other
analogous material, of moulds consisting of a number of spiral segments
or cores a formed with rims, webs, or flanges a¹, by which they mutually
support each other, such spiral segments or cores à being carried by a
piece of metal c suitably shaped to receive them, and placed inside a
mould box b having a removeable top 6' and bottom 62, all constructed
and arranged in manner substantially as shown and described.
Secondly. I claim the forming the spiral segments or cores a with
rims, webs, or flanges a¹ and without screws or segments of screws
formed thereon, but of a like section from end to end thereof, in
manner and for the purpose substantially as herein shewn and
described.
Thirdly. I claim the mode of forming the spiral segments or cores a
of tin or other readily fusible metal by casting them in moulds, as
herein described.
And Fourthly. I claim the mode of constructing moulds of spiral
segments a, whereby I dispense with the use of screws in putting the
parts of the mould together, in manner and for the purpose substantially
as herein shown and described.
In witness whereof, I, the said George Henry Roberts, have here-
unto set my hand and seal, this Nineteenth day of December,
in the year of our Lord One thousand eight hundred and seventy-
four.
ARA
TO