Improvements in the Manufacture of Explosive Projectiles.
Year: 1891

page_text: Date of Application, 3rd Oct., 1991
Complete Specification Left, 4th July, 1892-Accepted, 6th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Explosive Projectiles.
We, HUBERT HENRY GRENFELL, Captain Royal Navy, of 18 Ashburn Place
in the County of Middlesex, and JAMES GEORGE ACCLES of Holford Works,
Perry Barr, in the County of Stafford Mechanical Engineer do hereby declare the
nature of this invention to be as follows :-
:-
Our invention relates to improvements in the manufacture of explosive projectiles
or shells for ordnance and chiefly to projectiles of that class in which the body of
the projectile is first forged or otherwise formed with its rear end open and is then
provided with a separately formed base or plug inserted and secured in the aperture
existing in the said open end.
Heretofore in the manufacture of such projectiles it has been customary to secure
the base or plug in the shell body by screwing it into the said aperture and in the
Specification of a recent Patent No. 11616 Å.D. 1890 it is proposed to close the
end of the shell body down over a screw ring or bushing. The method of attach-
ment by screw threads is however objectionable for the reason that the surfaces of
the screw threads form inclines or wedges which by the pressure exerted on the
base in the discharge of the gun act to open or expand the rear portion of the
circumferential wall of the projectile. The deformation caused by such expansion
gives rise to undue friction between the surfaces of the projectile and the bore of
the gun and imperfect centreing of the projectile therein the result being more or
less inaccuracy in the shooting. Moreover the said wedging and expanding action
is increased when the shell strikes an object, such as an armour plate for instance
and shells frequently break in the armour by reason of the excessive friction of the
expanded and enlarged base or rear end and therefore fail to completely perforate
the plate and to burst effectively behind it.
Now according to our invention we obviate this difficulty and greatly improve
the manufacture of such projectiles as follows, that is to say instead of using a
screwed ring or bush and securing the same by screwing it into the end of the shell
body and closing the end of the shell body over it we make the aperture and the
base or bushing plain or smooth and secure the said base or bushing in the said
aperture in such a manner that there will be no wedging or expansive action of the
plug upon the body of the projectile. We form the said aperture of somewhat
larger diameter than the cavity in the body of the projectile so that at the inner
end of the said cavity there is a circular ledge or shoulder whereon the said base
bushing or plug is supported. We prefer to form the said plug or bushing with
its rear or outer end somewhat curved or rounded and to form across its outer end
shallow grooves or nicks. When the same is inserted in the aperture the end of
the cylindrical wall of the shell body will extend beyond the end of the base or
plug and we close or force down the extended or surplus portion over the said plug.
Some portion of the metal forced down enters the said shallow grooves or nicks
and the plug is thereby very firmly and solidly secured in its place. The said
grooves moreover prevent any twisting or turning of the base or plug while being
screwed to receive the fuse.
This method of manufacture not only ensures freedom from any tendency to
expansion and deformation of the shell body when the gun is fired and when the
shell strikes an object but it ensures great regularity and accuracy in respect of
the dimensions and weight of the completed projectile.
DL
1001

page_text: COMPLETE, SPECIFICATION.
Improvements in the Manufacture of. Explosive Projectiles.
We, HUBERT HENRY GRENFELL, Captain, Royal Navy, of 18 Ashburn Place
in the County of Middlesex, and JAMES GEORGE ACOLES, of Holford Works,
Perry Barr, in the County of Stafford, Mechanical Engineer, do hereby declare
the nature of this invention and in what manner the same is to be performed. to
be particularly described and ascertained in and by the following statement:-
Our invention relates to improvements in the manufacture of hollow projectiles
or shells for ordnance and chiefly to projectiles of that class in which the body is
first forged or otherwise formed with its rear end open and is then provided with a
separately formed base or plug inserted and secured in the aperture existing in the
said open end.
Heretofore in the manufacture of such projectiles it has been customary to secure
the base or plug in the shell body by screwing it into the said aperture and in the
Specification of a recent Patent, No. 11616 A.D. 1890 it is proposed to close the
end of the shell body down over a screw ring or bushing. The method of attach-
ment by screw threads is however objectionable for the reason that the surfaces of
the screw threads form inclines or wedges which by the pressure exerted on the
base in the discharge of the gun, act to open or expand the rear portion of the
circumferential wall of the projectile. The deformation caused by such expansion
gives rise to undue friction between the surfaces of the projectile and the bore of
the gun and to imperfect centreing of the projectile therein, the result being more
or less inaccuracy in the shooting. Moreover the said wedging and expanding
action is increased when the shell strikes an object, such as an armour plate, for
instance, and shells. frequently break in the armour by reason of the excessive
friction of the expanded and enlarged base or rear end and therefore fail to com-
pletely perforate the armour plate and to burst effectively behind it.
Now according to our invention we obviate this difficulty and greatly improve
the manufacture of such projectiles as follows, that is to say, instead of using a
screwed ring or bush and securing the same by screwing it into the end of the shell
body and closing the end of the shell body over it we make the aperture and the
plug or bushing plain or smooth and secure the said plug, or bushing in the said
aperture in such a manner that there will be no wedging or expansive action of the
plug upon the body of the projectile.
In order that our invention may be clearly understood we will now proceed to
describe with reference to the accompanying drawings the manner in which we
carry it into effect..
Figure 1 shews, in transverse section the rear end of a projectile ready for the
insertion of the base or bushing according to our invention.
Figure 2 represents a longitudinal central section of a finished projectile, with
the base, or bushing in place therein.
Figure 3 is a longitudinal central section of the plug or bushing apart from the
projectile, and.
Figure 4 shows the outer face of the bushing:.
Similar letters of reference indicate. corresponding parts in all the figures.
A.is the shell body.. B.is an. aperture in the rear end of the said shell body of
somewhat larger diameter than the cavity C therein so that at the inner end of the
said cavity there is a circular, ledge. or shoulder D whereon the base, bushing or
plug. E is supported.. The sides of the aperture forming its. circumference are
parallel.as are the corresponding sides of the plug E which come into contact
therewith. F is a seating formed upon the plug. E. to fit closely, to the said ledge
or shoulder D. The surface of the said ledge or shelf is at right angles with the
principal axis of the projectile or is inclined from the side of the aperture B
towards the said axis and the rear of the projectile.. G G are shallow grooves or
nicks formed in the outer: face of the plug. His a screw threaded opening formed

page_text: in the plug E and the base of the projectile to receive a fuze. I is a driving
ring and gas check.
We preferably form the plug or bushing E with its rear or outer end somewhat
curved or rounded as shown.
The grooves or nicks G are provided upon the said bush or plug in order that
when the same is inserted in the aperture B the end of the shell body, which
extends beyond the end of the base or plug may be closed down or forced down
over the said base or plug into the position in which it is shown in Figure 2. Some
portion of the metal thus forced down will enter the shallow grooves or nicks G,
and the plug is thereby very firmly and solidly secured in its place. The said
grooves moreover prevent any twisting or turning of the base or plug E while being
screwed to receive the fuze.
This method of manufacture not only ensures freedom from any tendency to
expansion and deformation of the shell body when the gun is fired and when the
shell strikes an object but it ensures great regularity and accuracy in respect of
the dimensions and weight of the completed projectile.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. In the manufacture of a hollow projectile the herein described method of
plugging or bushing the rear end thereof for the purposes specified.
2. A hollow projectile having at its rear end an enlarged cylindrical or parallel
sided aperture and a plain or unthreaded plug or bushing such as that herein
described fitted and secured therein substantially as shewn in Figure 2 and for the
purpose specified.
3. The provision of the grooves or nicks in the rear face of the said plug substan-
tially as and for the purpose specified.
Dat
Dated GIS ZUR uay UI JULY LOD
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.