IMPROVEMENTS IN SCREWS AND IN THE METHOD OF CASTING THE SAME
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at. the
Office of the Commissioners of Patents, with his Petition, on the
1st October 1869.-A communication from abroad by William
Allen Ingalls, of Chicago, Illinois, United States of America.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN SCREWS AND IN THE METHOD OF CASTING THE
SAME, a communication to me from abroad by William Allen Ingalls, of
Chicago, Illinois, United States of America, to be as follows:―
This Invention relates to an improved screw, and method of casting
the same, suitable for stools, chairs, presses, vices, and other purposes,
and consists in producing cast screws by casting them without seams or
scars by an improved method or mode, so as to produce screws without
seams or scars from the imperfect joining of the parts of the patterns
and of the flasks or moulds, which has heretofore been found impossible
in casting screws of any considerable size and length.
By the use of this improved method screws of almost any size and
adapted to almost all purposes for which such screws are used can be...

page_text: cheaply and expeditiously made, as all filing and fitting are rendered
unnecessary.
In preparing the mould for casting a screw with its head intended for
a music stool, for example, the patterns for the head are secured to a
plank or other suitable support, into which, if of wood, a metallic block
is inserted, which with the pattern when properly prepared forms a
guide, through which the patterns of the screw are turned when being
withdrawn out of the mould. Through the pattern and the metallic
block there is cut a female screw whose diameter and threads correspond
exactly with the diameter of and threads upon the screw patterns.
These patterns are then screwed in through the female screw. When
the patterns are thus arranged a mould box is placed upon the plank
and packed or tamped with any suitable moulding sand round and upon
the patterns, so as to leave distinct and accurate impressions thereof in
the sand when the screw patterns are removed. After the sand has
been properly packed the patterns are turned or screwed out from the
sand through the guide nut formed by the block and pattern for the
head, the operator being thus enabled to withdraw the pattern from
the mould without destroying or injuring the threads in the moulds.
The screw herein-before described is provided with a head cast with
four lugs or arms, whereby it may be attached to a seat for stools or
other purposes, but screws may be cast in this manner whether provided
with such a head or not, or without any head, and the threads may be
formed with square shoulders or with any desired angle or curve.
The screw patterns may be of iron or any other suitable material, and
may be turned out of the mould by inserting a pin in a hole near the
collar, or by a wrench, or in any other suitable manner. When the
patterns are withdrawn the plank with the patterns is removed, and
the moulds are then backed by a surface of moulding sand contained
in a separate box, which is hooked to the mould box or otherwise
suitably secured thereto.
The moulds are filled by pouring the metal into a hole provided with
gates leading into the moulds near or at the bottom thereof to prevent
"washing" or injury to the mould while the metal is being poured.