Improvements in the Percussion Fuzes of Explosive Shells.
Year: 1889

page_text: Date of Application, 11th Apr., 1889
Complete Specification Left, 8th Feb., 1890-Accepted, 8th Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Percussion Fuzes of Explosive Shells.
We, HENRY THOMAS ARBUTHNOT of Sutton Coldfield, Major-General in the Army
& GEORGE HOOкнAм of Nos. 7 & 8 New Bartholomew Street Birmingham, Manu-
facturer do hereby declare the nature of this invention to be as follows:-
Our improvements apply chiefly to the Hotchkiss percussion fuze. The "plug"
retaining the detonator in position as at present constructed is placed in the front
end of the cap. This plug has a cross-cut or nick in its head which is liable to
become clogged with the black-powder in the shell & may become unscrewed when
the fuze is removed; & the fulminate escaping, may lead, & is believed to have led
to accidents.
"
To obviate this, we make the front part of the " cap" solid with the " cap" not
formed by the "plug" as hitherto & we screw the plug into the back of the "cap
holding the detonator in position against the inside of the front of the cap. Hence
the detonator & the plug holding it in position are securely attached to, & the former
contained in, the cap; & should the cap by accident become unscrewed the fulminate
cannot escape, but is retained in the cap.
Or we may attain the same object by forming a thin metal thimble having a fire-hole
in its centre, which thimble fits over the end of the cap to a distance of say half an
inch down the cylindrical part of the cap.
DLL 1 CA: 1000
HENRY THOMAS ARBUTHNOT.
GEORGE HOOKHAM.
COMPLETE SPECIFICATION.
Improvements in the Percussion Fuzes of Explosive Shells.
We, HENRY THOMAS ARBUTHNOT, of Sutton Coldfield, Major General in the Army,
and GEORGE HOOKнAм, of Nos. 7 and 8 New Bartholomew Street, Birmingham,
Manufacturer, do hereby declare the nature of our invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
-
Our improvements apply chiefly to the Hotchkiss percussion fuze. The screw plug
retaining the detonator in position in the screw cap, as the said plug is at present
constructed, is placed in the front end of the said cap. This plug has a cross cut or
nick in its head which nick is liable to become clogged with the black powder in the
shell and the said plug may become unscrewed when the fuze is removed and the
fulminate escaping may lead, and is believed to have led, to accidents.
To obviate this we make the front part of the screw cap solid with the said cap,
that is, it is not formed by the screw plug as hitherto, and we screw the plug into the
back of the cap holding the detonator in position against the inside of the front of the
cap. Hence the detonator and the plug holding it in position are securely attached
to the cap and should the cap by accident become unscrewed the fulminate cannot
escape, but is retained in the cap.
Or we may attain the same object by forming a thin metal thimble having a fire
hole in its centre, which thimble fits over the end of the fuze to a distance of say about
half an inch down the cylindrical part of the cap.
Having explained the nature of our invention we will proceed to illustrate it in
connection with a percussion fuse of the Hotchkiss type.

page_text: Figure of the accompanying Drawing represents partly in vertical section and
partly in elevation, a percussion fuze for explosive shells constructed according to the
first part of our invention, Figure 2 represents in elevation and Figure 3 in vertical
section the screw cap and plug detached from the body of the fuze and Figure 4
represents the screw plug detached. Figure 5 represents partly in vertical section
and partly in elevation, a percussion fuze for explosive shells constructed according
to the second part of our invention and Figure 6 represents a portion of the same
detached.
In the Hotchkiss fuze as ordinarily constructed the screw plug which retains the
detonator in the screw cap constituting the front end of the fuze is screwed into the
front end of the said cap the said plug being exposed in the finished fuze (see
Figure 5). In order to prevent the possibility of the screw plug being accidentally
unscrewed from the cap when for any purpose the fuze is removed from the shell and
the detonator thereby so exposed that accidental detonation may occur, we make the
opening into the screw cap containing the detonator at the inside instead of at the
outer part of the said cap and after the insertion of the detonator and disc into
the said cap, we first screw the plug into the cap and afterwards screw the cap, thus
charged with the detonator and closed, into the body of the fuze. In the completed
fuze the screw plug, securing the detonator in the screw cap, is not exposed and
cannot be removed either by design or accident.
In the accompanying drawing, a represents the screw cap containing the detonator ;
6 represents the screw plug by which the said cap a is closed and c represents the
detonator and disc enclosed in the cap a.
In the second part of our invention, represented in Figures 5 and 6, we make the
screw cap containing the detonator and the plug screwed into the cap in the ordinary
way, the second part of our invention consisting of an addition to the ordinary
percussion fuze of the Hotchkiss type as hereinafter explained.
By comparing the respective parts a and b in Figures 1 and 5 the improvements in
the said parts a and b constituting the first part of our invention will be readily
understood. The opening in the screw cap a in the fuze represented in Figure 1, at
which opening the detonator and disc are introduced into the cap, is at the base of
the cap or in that part which in the finished fuze is within the body of the fuze. In
the ordinary fuze contained in Figure 5 the opening in the cap a at which the
detonator and disc are introduced into the cap is in the finished fuze external. The
plug b, by which, according to the first part of our invention, we secure the detonator
in its place in the cap a is in the finished fuze in the interior of the body of the
fuze. Hence when the fuze is unscrewed for any purpose from the explosive shell,
in which has been screwed, even should the cap a be accidentally unscrewed from
the body of the fuze, the detonator is not exposed and the risk of accident herein-
before referred to is obviated..
The second part of our invention is illustrated in Figures 5 and 6 in connection
with a Hotchkiss fuze. This part of our invention consists of a light metallic
thimble or tubular covering d slightly elastic and fitting with friction on the upper
end of the fuze covering the end of the screw cap a in which the plug 6 for securing
the detonator in the said cap is screwed. The said thimble or tubular covering d has
a perforation e at top through which the fire or flash from the fuze passes to the
powder in the shell. In unscrewing a fuze of this kind from the shell if by the
caking of the powder in the shell or the corrosion of the exterior of the thimble d
any resistance to the removal of the thimble occurs the fuze in being unscrewed
from the shell leaves the said thimble behind and there is no risk of the plug being
unscrewed from the body of the fuze and the possibility of accident hereinbefore
referred to is obviated.
The application of our improvements to the percussion fuzes of explosive shells
other than those of the Hotchkiss type differs in no essential respect from its
application to the percussion fuzes of the Hotchkiss type as hereinbefore described.

page_text: Having now particularly described the nature of our invention and the manner in
which the same is to be performed we declare that we claim as our invention of
Improvements in the percussion fuzes of explosive shells,”
«
"
First. Making the opening at which the detonator is introduced into the screw cap
of the fuze and into which cap, the screw plug for retaining the detonator in position
in the said cap, is screwed, at the inner end of the said cap or that end which in the
finished fuze is situated in the body of the said fuze for the purpose and substantially
as herein before described and illustrated in Figures 1, 2, 3 and 4 of the accompanying
Drawing.
Secondly. The adaptation to or combination with a percussion fuze of the Hotchkiss
or other like type, of a light perforated metallic thimble or tubular covering which
prevents the accidental removal of the screw plug when the fuze is uncrewed from the
explosive shell substantially as hereinbefore described and illustrated in Figures 5
and 6 of the accompanying Drawing.
Dated this 7th day of Fahrn 1800
W. T. WHITEMAN,
Agent for the Applicants.