Improvements in the Construction of Electrical Vent Sealing Tubes for Firing Ordnance.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Electrical Vent Sealing Tubes
for Firing Ordnance.
HENRY CAPEL LOFFT HOLDEN Captain, Royal Artillery Royal Arsenal
Woolwich London S.E. 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 :-
For the purpose of preventing the escape of gas, gaseous fluid or products of
combustion from the vent of the gun from the failure of the internal portion of the
vent sealing tube, I use a conical metal plug which has an external screw thread or
screw threads cut on it for the purpose of containing the insulated conductor or
conductors leading to what is known as the bridge of the tube, which latter may be
conveniently arranged on the base of the conical plug above mentioned. This
conical plug fits into the shell of the tube which is suitably bored to take it and
the insulated conductor or conductors pass out through a suitable aperture in the
head of the tube shell.
On firing the tube in the ordinary manner, the pressure exerted within it by the
combustion of the charge forces back the conical plug tightly into the portion of
the shell which is bored for it and crushing up the screw threads and insulated
conductors forms a gas tight joint, which effectually prevents any escape past the
conical plug and through the head of the tube.
In order that my said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the figures
on the annexed sheet of drawings, the same letters of reference indicating
corresponding parts in both figures.
Fig. 1 represents in section a vent-sealing tube of the two wire description
for firing ordnance. A is the conical metal plug having a double screw thread
cut on its exterior; and in these two threads lie the insulated wires or conductors C;
the one ends of these wires lead to the usual bridge D which is imbedded in
guncotton or other suitable substance whose ignition fires the gunpowder H with
which the other portion of the tube is filled, and thus ignites the charge of the gun;
the other ends of these wires pass through the head of the tube E and are connected
to the firing wires.
"
Fig. 2 similarly represents a section of a single wire or so called "wireless
tube; in this case only a single screw thread is cut on the conical plug A. and in
this the insulated wire or conductor C is laid leading to one end of the bridge D,
the other end of the bridge being connected to the metal of the conical plug and of
the tube.
The other end of the insulated wire or conductor C passes through the head of
the tube E and is fastened to the metal disc G, which itself is insulated from the
tube by means of the layer of insulating material F.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed I declare that what
1 claim is:
The use in a vent sealing tube for firing ordnance, of a conical metal plug or its
equivalent substantially as and for the purpose herein before described.
Dated this 11th (eleventh) day of May 1891.
HENRY CAPEL LOFFT HOLDEN,
Captain Royal Artillery.