IMPROVEMENTS IN THE MANUFACTURE OF GUNS OR HEAVY ORDNANCE OF CAST METAL
Year: 1866

page_text: LETTERS PATENT to Jaques Hermann Auguste Gruson, of Buckau, in
the Kingdom of Prussia, Engineer, but at present residing at the
Westminster Palace Hotel, in the City of Westminster, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF GUNS OR HEAVY ORDNANCE OF
CAST METAL."
Sealed the 14th May 1867, and dated the 20th November 1866.
PROVISIONAL SPECIFICATION left by the said Jaques Hermann Auguste
Gruson at the Office of the Commissioners of Patents, with his Petition,
on the 20th November 1866.
I, JAQUES HERMANN AUGUSTE GRUSON, of Buckan, in the Kingdom of
Prussia, Engineer, but at present residing at the Westminster Palace Hotel,
in the City of Westminster, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF GUNS OR HEAVY ORDNANCE OF CAST
METAL," to be as follows:-
This Invention has for its object to produce guns of cast metal of greatly
increased strength so that the gun will be enabled to resist the concussion
and strain to which it will be subjected on being fired with heavy charges of
powder. To this end I employ a mixture of white and best grey charcoal
iron, and which I denominate Gruson metal; this metal must be refined and
freed from all impurities such as sulphur, silica, phosphorus, and copper, and
when cast in an iron mould it is chilled on the surface, and its strength
and tenacity greatly increased. I also heat the back of the iron mould by

page_text: pouring in molten cast iron which will prevent the casting from cooling too
rapidly.
In casting guns with the Gruson metal I place the mould upright so as to
cast the gun on end, and the molten metal is supplied or run into the
mould at the lower end, a vertical channel extending from the top to the
bottom of the-mould-having been prepared for the purpose. An air hole is
made at the upper end to allow the air to escape from the interior of the
mould, and as the metal rises gradually in the mould in consequence of the
supply of molten metal from beneath, it follows that there is less risk of air
bubbles, flaws, or defects in the casting than when articles are cast in the
ordinary manner. A greater density of metal and consequently a stronger
breech and after part of the gun will also be thereby produced.
"SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
'by the said Jaques Hermann Auguste Gruson in the Great Seal. Patent
Office on the 17th May. 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAQUES
HERMANN AUGUSTE GRUSON, of Buckau, in the Kingdom of Prussia, Engineer,
but at present residing at the Westminster Palace Hotel, in the City of
Westminster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date. the Twentieth day of November, in the year of our
"Lord One thousand eight hundred and sixty-six, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the 'said Jaques Hermann Auguste Gruson, Her special licence that I,
the said Jaques Hermann Auguste Gruson, my executors, administrators, and
assigns, or 'such others as I, the said Jaques Hermann Auguste Gruson, 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 för "IMPROVEMENTS IN THE MANUFACTURE OF GUNS
OR HEAVY ORDNANCE OF "CAST METAL," upon the condition (amongst others)
that I, 'the said Jaques 'Hermann Auguste Gruson, my executors or admini-
"strators, 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

page_text: cause the same to be filed in the Great Seal Patent Office within six calendár
inonths next and immediately after the date of the said Letters Patent.
i
NOW KNOW YE, that I, the said Jaques Hermann Auguste Gruson,
'do hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained in
and by the following statement, reference being had to the Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to say)
This Invention has for its object to produce guns of cast metal of greatly
increased strength, so that the gun will be enabled to resist the concussion and
strain to which it will be subjected on being fired with heavy charges of
powder. To this end I employ a mixture of white and best grey charcoal
iron, and which I denominate "Gruson metal; " this metal must be refined
and freed from all impurities, such as sulphur, silica, phosphorous, copper, &c.,
'and 'when cast in an iron mould it is chilled on the surface, and its strength
and tenacity greatly increased; I also heat the back of the iron mould by
pouring in molten cast iron which will prevent the casting from cooling too
rapidly.
In casting guns with the Gruson metal I place the mould upright so as to
cast the gun on end, as shewn in the accompanying Drawing, which represents
a longitudinal vertical section of a mould constructed and arranged to cast a
piece of ordnance according to my improvements.
The molten metal is supplied or run into the metal mould a, a, through a
gate or gates b, b, and down a vertical channel or passage c, which conducts
it to the lower end of the mould. The vertical channel c.extends from the
top or gate.6 to the bottom of the mould, and consequently considerable
pressure is given to the molten metal in the mould. An air hole is made at
the upper end to allow the air to escape from the interior of the mould, and as
the metal rises gradually in the mould a, in consequence of the supply of
molten metal from beneath, it follows that there is less risk of air bubbles,
flaws, or defects in the casting than when articles are cast in the ordinary
manner. A greater density of metal and consequently a stronger breech and
after part of the gun will also be thereby produced. The metal having risen
in the mould up to the level of the muzzle of the gun is allowed to run over
through the lateral openings d, d, into and down a space e, e, constructed at the
back of the metal mould a, which is thus kept from cooling too fast; the
molten metal is continued to be poured into the gates b, b, until not only
the mould but also the space e is fully charged, and until it runs over into
the spout f. By this means the molten metal in the mould is cooled gradually
and consequently in very fine crystals, which will indicate greater strength

page_text: than usual. When the casting is removed from the mould all the superfluous
metal may be removed and made to serve for another casting.
Having now described my Invention of "Improvements in the Manufacture
of Guns or Heavy Ordnance of Cast Metal," and having explained the manner
of carrying the same into effect, I would have it understood that I do not
claim the use of the mixture I have termed "Gruson's metal," except when
used in casting a gun as herein described, nor do I claim the use of any
particular proportions of white and best grey charcoal iron, as these proportions
must be varied according to the quality of the two kinds of iron respectively,
and the purity in which they can be obtained. A manufacturer from experience
and by examining the quality of his mixture of the two kinds of iron will be
able readily to ascertain whether more of one metal or of the other is required
in order to give to the mixture the requisite hardness, toughness, and strength.
Although I recommend the use of the mixture of metals which I have described,
I do not confine myself thereto; but what I claim as my Invention is the
manufacture of guns of cast metal cast in the manner and by means of
moulding apparatus substantially as herein described.
In witness whereof, I, the said Jaques Hermann Auguste. Gruson,
have hereunto set my hand and seal, the Thirteenth day of May, in
the year of our Lord One thousand eight hundred and sixty-seven..