Improvements in and relating to Percussion-fuses.
Year: 1888

page_text: Date of Application, 1st Nov., 1888
Complete Specification Left, 23rd July, 1889-Accepted. 24th Aug.. 1889
PROVISIONAL SPECIFICATION.
Improvements in and relating to Percussion-fuses.
1, MAURICE DELMARD, of 11 Victoria Road, Old Charlton, in the County of Kent,
Gentleman, do hereby declare the nature of this invention to be as follows:-
My invention relates to percussion-fuses, and its main object is to provide an
improved base-fuse which will be simple in construction and will not be liable to
accidental explosion by concussion in the handling or transport of the projectile or
shell in which it is fixed. My improved fuse can, however, he adapted for use in the
point or head of a projectile or shell if desired.
An important feature of my said invention is the utilization of the inertia of the
charge or contents of the shell for effecting the adjustment of the parts relatively to
each other, when the shell is discharged from a gun, so that the needle or striker,
which is, under ordinary conditions, held or kept out of reach of the detonator, will,
when the parts are thus adjusted, be free to strike and explode the said detonator
upon the impact of the shell against an object.
My said invention is conveniently and advantageously carried into practice as
hereinafter described, that is to say:-The outer chamber or casing which contains
the movable parts is made in the form of a hollow cylinder closed at one end, and is
provided with an external screw-thread for securing it in the projectile or shell. In
this cylinder is arranged a discharging-plunger in which is fixed the needle or striker.
In the open end of the said cylinder is inserted a hollow movable plug or plunger
which contains the detonator and a charge of powder. This plug or plunger is
retained in the said cylinder by means of a screw-threaded ring or collar and set-
screw, or in any other convenient manner, and is so fitted in the cylinder that, when
the shell is discharged from a gun, the backward pressure exerted upon the said plug
or plunger, due to the inertia of the charge or contents of the shell, will force the said
plug or plunger inward towards the discharging-plunger. To provide for limiting
this inward movement, the said plug or plunger is formed with one or more shoulders
adapted to engage with corresponding shoulders on the interior of the cylinder. In
some instances, the said plug or plunger is made with one or more conical or taper
portions or is otherwise so constructed as to increase its resistance to such inward
movement or adjustinent, and hold it firmly in position when adjusted.
The discharging-plunger has applied to one end thereof a plate or disc which fits
into a recess or cavity in the said plug and bears against a shoulder therein, so that
the operation of the needle or striker is effectually prevented. The said plate or disc
is made of such strength that it is capable of resisting deformation by the shocks or
concussion to which the fuse is liable to be subjected in handling and transport, but
will yield to the pressure exerted upon it by the said plug when the projectile or shell
is discharged from a gun, so that it will be cupped or sheared and forced into the
hollow plug. The discharging-plunger of the fuse will thereby be liberated, so that,
on the impact of the shell against an object, the said plunger will continue to move
forward and thus cause the explosion of the said shell.
The aforesaid retaining plate or disc is, in some instances, secured to the dis-
charging-plunger by means of a screw which has the needle or striker formed
herewith.
The movable plug is formed with a chamber for the powder-charge, which chamber
s closed by a screw-cap baving an aperture for communication between the said
hamber and the powder-chamber of the shell.
If desired I combine, with the discharging-plunger, a spiral or other spring
which tends to hold the same against the closed and of the chamber or casing.

page_text: I sometimes substitute for the aforesaid retaining plate or disc, other suitable means
for keeping the needle or striker out of reach of the detonator until the said plug is
forced inward as above described.
In adapting my invention to a fuse for insertion in the point or head of a projectilo
or shell, sometimes so arrange the movable plug that its own inertia and the
resistance of the air will be sufficient to force inward the said plug for the purpose
above specified.
Dated this 1st day of November 1888.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Percussion-fuses.
I, MAURICE DELMARD, of 11, Victoria Road, Old Charlton in the County of Kent,
Gentleman, 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:―
My invention relates to percussion-fuses for explosive projectiles or shells and its
main object is to provide an improved base-fuse of simple construction and not liable
to accidental explosion by reason of any shock or concussion to which it may be
subjected in the handling or transport of the projectile or shell.
My improved fuse is so constructed that the striker is held out of reach of the
primer or detonator until the relative position of these parts is changed by the dis-
charge of the shell from a gun, and the primer or detonator is thus brought within
reach of the striker so that it will be exploded thereby, upon the impact of the shell
against an object.
An important feature of my said invention is the utilization of the inertia of the
charge or contents of the shell for effecting this adjustment or change of position of
the parts, when the said shell is discharged from a gun.
In the accompanying drawing, I have shown how my said invention may be con-
veniently and advantageously carried into practice.
Figure 1 is a longitudinal central section of one form of my improved fuse, the
parts being shown in the position which they occupy relatively to each other, when
the fuse is ready for use.
Figure 2 is a longitudinal central section of part of a shell with the said fuse fixed
in the base thereof, the parts being shown in the position which they occupy
relatively to each other, after the shell has been discharged from a gun, but before
impact of the said shell.
Figures 3 and 4 are similar views to Figures 1 and 2, illustrating another form or
modification of my improved fuse.
Figure 5 is a longitudinal central section illustrating a further modification of my
invention.
Like letters indicate corresponding parts throughout the drawing.
A is the shell; B is the bursting-charge thereof; C is the chamber or casing of the
fuse.
The said chamber or casing C is made in the form of a hollow cylinder closed at
one end, and is provided with an external screw-thread a for securing it in the base of
the shell. In the said chamber or casing C is arranged a discharging-plunger bin
which is fixed the needle or striker c. In the open end of the said chamber or
casing C is inserted a hollow movable plug or plunger d in which are arranged the
detonatore and a magazine f containing a charge 9 of powder or other suitable
explosive material. is a screw-threaded cover which is provided with a vent-hole h',
and by which the upper end of the said magazine is closed after the explosive
inaterial has been inserted therein. The movable plug d carrying the detonator is
retained in the chamber or casing (by means of screw-threaded rings or collars

page_text: which may be locked in position by a set-screw; or in any other convenient manner.
The plug d is so fitted in the chamber or casing C that, when the shell is discharged
from a gun, the backward pressure exerted upon the said plug d by reason of the
inertia of the charge or contents of the shell will force the said plug inwards towards
the discharging-plunger b and striker c. To limit this inward movement of the plug,
the said plug is formed with shoulders d' adapted to engage with or bear against
corresponding shoulders C on the interior of the chamber or casing () as shown in
Figures 2 and 4. In some instances, the said plug d is made with one or more
conical or taper portions as in Figure
or is otherwise so constructed as to increase
its resistance to such inward movement or adjustment and ensure its being held
firmly in position when so adjusted.
The discharging-plunger has applied to one end thereof a plate or disc j, which,
in the fuse shown in Figures 1 and 2, is secured in position upon the said plunger by
means of the needle or striker c which is screwed into the upper end of the said
plunger b, a square, hexagonal or other suitably shaped collar, e¹, being formed on
the said needle or striker to facilitate the operation of screwing it into the plunger.
A set-screw c² is provided for firmly retaining the needle or striker in position in the
plunger. The plate or discj fits into a recess or cavity in the lower end of the
movable plug d and bears against a shoulder therein so that the operation of
the needle or striker c is effectually prevented until the plunger b is released as
hereinafter described. The plate or disc j is made of such strength that it will resist
deformation by reason of any shock or concussion to which the fuse is liable to be
subjected in handling and transport, but will yield to the pressure exerted on it by
the said plug d when the projectile or shell is discharged from a gun, so that it will be
cupped or sheared and forced into the hollow plug as shown in Figure 2. The dis-
charging-plunger of the fuse will thereby be liberated, so that, on the impact of the
shell against an object, the said plunger will, by reason of the momentum imparted
to it, continue to move forward and thus cause the explosion of the detonator and
the consequent bursting of the shell.
To provide for retaining or holding the discharging-plunger 6 in position against
the rear end of the chamber or casing (, and thus preventing rebound of the said
plunger when the disc j has been cupped or sheared as above mentioned. a spring bl
is arranged between the said plunger and the plug d. In some instances, morcover,
I
insert a disc 62 of lead, or other suitable material into the lower end of the dis-
charging-plunger b.
f
I prefer to arrange in the lower end of the magazine fa dome-shaped perforated
plate and to place a disc of paper or other suitable material between this plate and
the powder g.
By these means, I obviate any liability to accidental explosion of the
detonator, when the shell is discharged from the gun, by reason of the inertia of the
powder in the magazine f.
When the discharging-plunger and striker and the detonator occupy the relative
positions shown in Figure 1, with the plate or discj between them, it is obvious that
the said detonator cannot be accidentally exploded. When, however, the shell is
fired from a gun, the plug d carrying the detonator will be moved towards the said
plunger and striker by the backward pressure exerted upon the said plug by reason
of the inertia of the charge or contents of the shell, and the said plate or disc will be
cupped or sheared, so that, when the shell strikes an object, the plunger b and
striker c will by the momentum imparted thereto be driven forward and will strike the
detonator, thereby causing the bursting of the shell.
Figures 3 and 4 illustrate a modification of my invention wherein a hollow
cylinder or tubular guard k is held between the plug d and the plate or disc; and
surrounds the needle or striker c and spring b¹. The plate or disc j is, in this instance,
secured in position upon the discharging-plunger b by means of a nut 6³ fitted upon a
correspondingly screw-threaded portion of the said discharging-plunger. And the
said discharging-plunger is made with a conical or taper portion for the purpose
hereinafter specified. In this arrangement, moreover, the needle or striker c is forined
in one piece with the said discharging-plunger b.

page_text: On the shell being discharged from the gun, the plug d is forced inward by the
inertia of the charge, in the manner hereinbefore described, carrying with it the
tubular guard and cupping the disc j as shown in Figuro 4 or shearing the said
disc.
After the said disc is cupped or sheared, the momentum imparted to the said
tubular guard k causes it to assume the position shown in Figure 4 and to, bind
tightly upon the conical part 65 of the discharging-plunger b. During this movement
of the tubular guard k, the cupped disc j scrapes against the inside of the said guard
and prevents any rebound of the same or of the discharging-plunger. On the impact
of the shell against an object, the discharging-plunger and tubular guard kare by
their momentum moved forward together with the needle or striker e which is thus
caused to explode the detonator.
I sometimes substitute for the retaining plate or disc j, other suitable means for
keeping the needle or striker and the detonator apart until the said plug is forced
inward as above described.
It may be advantageous to arrange the movable plug d as shown in Figure 5 so
that, when moved inward by the powder in the shell, it will be flush with the forward
end of the casing C.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
First. A percussion-fuse wherein the primer or detonator is held out of reach of
the needle or striker but will, upon the discharge of the shell from a gun, be moved
towards the said striker, for the purpose above specified.
Second. A percussion-fuse wherein the inertia of the charge or contents of the
shell is utilized for changing the relative positions of the primer or detonator and
striker when the shell is discharged from a gun, for the purpose above specified.
Third. The combination, with the discharging-plunger and the striker, of a inovable
plug carrying the primer or detonator, and a plate or disc or other suitable device
which will retain the said plug in position but will permit the inward or backward
movement thereof when the shell is discharged from a gun, for the purpose above
specified.
Fourth. The combination, with the discharging plunger, the striker and the
movable plug carrying the primer or detonator, of the tubular guard and the plate or
disc, substantially as, and for the purpose, set forth.
Fifth. The improved percussion-fuse constructed substantially as described with
reference to either of the forms or modifications illustrated in the accompanying
drawing and operating in the manner hereinbefore specified.
Dated: thi. 19th dov of Túl. 1000
Datad this 19th J
th day of July
1000
M. DELMARD.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.