IMPROVEMENTS IN GAS CHECKS
Year: 1877

page_text: LETTERS PATENT to Robert Hadfield, of Sheffield, in the County of York,
Manufacturer, for the Invention of "IMPROVEMENTS IN GAS CHECKS."
the 26th February 1878, and dated the 30th August 1877.
PROVISIONAL SPECIFICATION left by the said Robert Hadfield at the Office
of the Commissioners of Patents on the 30th August 1877.
86
ROBERT HADFIELD, of Sheffield, in the County of York, Manufacturer. IM-
PROVEMENTS IN GAS CHECKS."
In the Specification of my Patent, No. 904, of the 6th of March 1877, I have
described an improved method of casting external, radial, or circumferential grooves
or projections in or on the base end of my improved hollow cast-steel projectiles, for
the purpose of such projectiles being rotated by means of suitable metal gas checks
applied thereto and thus facilitating their flight.
Now my improvements in gas checks consist in making the same of a suitable
and convenient shape, according to the form of the groove or projection formed in
or on the base of the projectile itself, so that the gas check will adapt itself more
readily to the base of the projectile.
My improved gas check may be attached to the projectile either mechanically
or by preference automatically, by allowing the pressure of the gas generated by
the explosion of the gun to force the gas check in or on the before-mentioned
external, circumferential, or radial grooves or projections cast on the base end of
the projectile, thus making the attachment more secure than if such gas check
were affixed to the base of the shell by means of screws or other mechanical
appliances, and thus avoiding the cost and labour attendant upon the use of bolts
or other fastenings.
I also take care to make my improved gas check of such a form as is most suitable
to receive the gas evolved from the combustion of the gunpowder used in muzzle-
loading guns.
Gas checks manufactured upon my improved principles give to the projectile the

page_text: proper amount of rotation due to the rifling of the gun. Such gas checks may be
made either of brass or copper, or of any other suitable metal or material.
One of the principal advantages of my improved gas checks is that by their
use much difficult machine labour is saved, as they dispense with all necessity for
boring stud holes and inserting studs, or cutting and turning the grooves as now
practised on forged steel and other shells.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Hadfield in the Great Seal Patent Office on the 28th
February 1878.
"IM-
ROBERT HADFIELD, of Sheffield, in the County of York, Manufacturer.
PROVEMENTS IN GAS CHECKS."
This Invention has for its object an improved automatic gas check for the pur-
pose of rotating shot or shell in muzzle or breech-loading ordnance. Such improved
gas check may be applied to shot or shell, cast either in chilled iron or in steel, or
in a compound of both, and having a reduced base made slightly taper, at the
bottom of which I form an undercut groove, and on the outer part of which base
I cast suitable projections as described in the Specification of my Patent No. 904,
of 6th March 1877.
I cast my improved automatic gas check in any suitable metal, such as yellow
brass, or by preference copper, with a tongue or projection thereon. The peculiar
form and construction of such gas check will be better understood by reference
to Figure 1 of the accompanying Drawings, which is a sectional view, shewing the
gas check A, placed on the base of a shot or shell Z, with the tongue B of the gas
check partly filling the undercut groove F, formed on such base, whilst the under
side of the gas check rests on the top of the projections E, Figure 2, cast externally
on the base of the shell as before mentioned.
The operation of the gas check is as follows:--The instant the powder forming
the charge of the gun explodes, the soft metallic gas check A is driven forward with
tremendous force, causing the tongue thereof, B, to be forced into and fill the before-
mentioned undercut groove F, thus firmly attaching the gas check to the projectile,
and effectually precluding all risk of its being prematurely detached therefrom,
whilst its bottom is forced in between the projections cast on the base of the
shell. The external surface of the gas check readily adapts or moulds itself to the
rifling of the gun whatever shape or pattern it may be, and it thus effectually
assists in rotating the shot or shell when discharged.
I would here observe that the following are some of the principal advantages
which I claim for my improved automatic gas check-
First. Such gas check being automatic in its action instantaneously attaches
itself firmly to the base of the projectile immediately the powder explodes, thereby
avoiding the great risk to which all fixed gas checks have hitherto been liable in
transit of being bruised or otherwise injured.
Secondly. The use of my improved gas check effectually dispenses with the
present defective system of weakening projectiles by cutting away or boring the
sides of the same to provide for the reception of studs or other fastenings.

page_text: And, thirdly. By the use thereof great economy is effected, as the heavy cost
in time and labour hitherto involved in boring and studding is entirely dispensed
with.
In order that my present Invention may be more readily understood, I have
shewn at Figure 2 of the accompanying Drawings a plan view of the bottom of a
shell manufactured on my improved patented principles, wherein C indicates the
charging hole E, the projections cast on the bottom thereof for the purpose of
rotating the same; and the dotted line F, the undercut groove for the reception of
the tongue of the gas check.
Having now particularly described and ascertained the nature of my said Invention
and the manner of carrying the same into effect, I would have it understood that
what I claim and desire to secure by the herein-before in part recited Letters
Patent is, the casting an automatic gas check in any soft metallic substance (prefer-
ably in copper or yellow brass) in the form shewn at A, B, Figure 1, of the accom-
panying Drawings, whereby, when applied to shot or shell made upon my improved
patented principles, as described in the Specification of my Patent, No. 904, of
6th March 1877, such gas check, immediately upon the explosion of the powder,
becomes instantaneously, automatically, and firmly attached to the base of the
projectile, thus effectually rotating the same, and so entirely dispensing with the
present vicious system of weakening the shot or shell by cutting or boring, as
herein-before mentioned, and saving the enormous labour and cost consequent
thereon.
In witness whereof, I, the said Robert Hadfield, have hereunto set my hand
and seal, this Twenty-seventh day of February, in the year of our Lord One
thousand eight hundred and seventy-eight.
ROBERT HADFIELD. (L.S.)