Improvements in Percussion Fuses.
Year: 1890

page_text: Date of Application, 2nd July, 18901
Complete Specification Left, 1st Apr., 1891-Accepted, 2nd May, 1891
PROVISIONAL SPECIFICATION.
Improvements in Percussion Fuses.
I, KARL KUNO MALMSTRÖM, of 32 Victoria Street, in the City of Westminster,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention has for its object improvements in percussion fuses.
I make these fuses in such manner that they are "armed or rendered active by
the pressure of the powder gases on the base of the fuse whilst the same is in the
gun; this pressure bends the metal of which the base of the fuse is composed and
by so doing liberates a pellet which by its forward movement when the projectile
strikes fires the bursting charge.
According to one arrangement I form a cylindrical cavity in the rear of the pellet
and fit within it a hollow or tubular stud fixed to the fuse body. A wire passes
through this stud and its ends enter holes in the pellet. A pin abuts on this wire
and also upon the base of the fuse. When the gun is fired the pressure in the gun
bends inwards the metal forming the base of the fuse, the pin is thus thrust forward
the wire is displaced and the pellet is liberated ready for action. The flexible
bottom may be part of the base body or may be screwed fast into it so as to remain
immoveable when in action except in so far as it is bent or deformed by the
pressure.
Sometimes in place of the wire and pin I employ catches to take hold of a stem
projecting from the pellet. These catches are upon a piece which is thrust
forward by the base of the fuse when it becomes bent and so the catches are
brought against inclines within the fuse which cause them to release their hold of
the stem.
Or I may arrange the catches in such manner that the pressure of a pin moved
by the flexible base of the fuse upon a part in connection with the catches causes
them to spring apart and release the pellet.
Or I may form a head upon the pin and cause this to be received into a cavity
within the pellet. This pin so long as it retains the position in which it is originally
placed, locks the pellet fast within the fuse body but when the base of the fuse body
is bent by the pressure of the powder gases upon it the pin is driven forward and its
head no longer prevents the pellet moving so far as to bring its point into contact with
the patch of fulminate by which the bursting charge of the projectile is ignited.
Dated this 1st day of July 1890.
KARL KUNO MALMSTRÖM.
COMPLETE SPECIFICATION.
Improvements in Percussion Fuses.
I, KARL KUNO MALMSTRÖM, of 32 Victoria Street, in the City of Westminster,
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:-
This invention has for its object improvements in percussion fuses.
I make these fuses in such manner that they are "armed or rendered active by
the pressure of the powder gases on the base of the fuse whilst the same is in the
gun; this pressure bends or deforms the metal of which the base of the fuse is
composed and by so doing liberates a pellet which by its forward movement when
the projectile strikes fires the bursting charge.

page_text: According to one arrangement I form a cylindrical cavity in the rear of the
pellet and fit within it a hollow or tubular stud fixed to the fuse body. A wire
passes through this stud and its ends enter holes in the pellet. A pin abuts on this
wire and also upon the base of the fuse. When the gun is fired the pressure in the
gun bends inwards the metal forming the base of the fuse, the pin is thus thrust
forward the wire is displaced and the pellet is liberated ready for action.
This arrangement is represented in longitudinal section by Figure 1 of the
annexed drawings. a is the fuse body usually of brass and adapted to be screwed
into the base of the projectile. is a cap screwed in to close the body a in front.
c is a patch of fulminate lodged in a recess in the cap and protected in the usual
manner. d is the pellet it is armed in front with the point d to strike and explode
the fulminate. e is a stud piece of hard metal screwed into the fuse body and
carrying the tubular stud e f is a soft metal wire inserted through holes in the
pellet and in the stud and then bent to the form shown; it locks the pellet fast to
the stud. g is a steel pin passing through a hole in the stud piece and abutting at
one end upon the flexible base of the fuse body and at the other end on the wire f.
When the gun is fired the base of the fuse case is deformed and the pin thrusts
the wire into the interior of the hollow stud e¹ and frees the pellet. When the
projectile strikes, the pellet goes forward and fires the bursting charge in the usual
way. The flexible bottom may be part of the base body as in Figure 1 or may be
screwed fast into it as in Figure 2 so as to remain immoveable when in action except
in so far as it is bent or deformed by the pressure.
g
In this arrangement the cap is dispensed with, the fulminate patch being set in
a recess in the body a. The body is closed in rear by a base plug a' screwed in.
The base plug is deformed when the gun is fired and the operation is the same as
in Figure 1.
This
Sometimes in place of the wire and pin I employ catches to take hold of a stem
projecting from the pellet. These catches are upon a piece which is thrust forward
by the base of the fuse when it becomes bent and so the catches are brought against
inclines within the fuse which cause them to release their hold of the stem.
arrangement is illustrated by Figure 3. The pellet d has a stem dx projecting from
it rearwards through a central hole in the piece e. The base plug a¹ has a spring
clip riveted or otherwise fixed to it; shown in plan by Figure 34. The clip has
arms which tend inward, they terminate in claws which take hold of a head upon
the stem d*. When the gun is fired and the base plug is deformed the clip is
thrust against inclines e² e² on the piece e and these open the clip and release the
pellet.
Or I may arrange the catches in such manner that the pressure of a pin moved
by the flexible base of the fuse upon a part in connection with the catches causes
them to spring apart and release the pellet. This arrangement is illustrated by
Figure 4; here the cap bis provided with a cross piece on which the pellet dis
seated and it is held down upon its seat by a clip which in this case consists of a
narrow steel band bent twice at right angles it passes beneath the cross piece and
has claws at its end which rest upon the front of the pellet. When the head g¹ of
the ping thrusts upon the centre part of the clip its arms separate and release the
pellet. Or according to another arrangement illustrated by Figure 5 I form a
head upon the pin y and cause this to be received into a cavity within the pellet d.
This pin g so long as it retains the position in which it is originally placed, locks
the pellet fast within the fuse body but when the base of the fuse body is bent by
the pressure of the powder gases upon it the pin is driven forward and its head g' no
longer prevents the pellet moving so far as to bring its point d'into contact with
the patch of fulminate c by which the bursting charge of the projectile is
ignited.
Figure 6 shows a modification of Figure 5. In this case there is a screw nut at
the inner end of the pin g. After the nut is screwed on, the end of the pin is
opened out so that it will not unscrew.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I would state that I am
aware that fuses have before been made in which the release of the pellet has been
obtained by the pressure of the powder gases in the gun chamber causing the move-
ment of a plug in a cavity into which it is fitted but with this arrangement there is
always some danger of the passage of the powder gases into the interior of the fuse;
and the fuse case not being hermetically closed is in other respects objectionable,
what I claim is :-
1. A fuse armed or rendered active substantially as described by the bending or
deformation of the fuse case or base of the fuse resulting from the pressure of
the powder gases thereon when the gun is fired.
2. A fuse in which the bending or deformation of the fuse case or base of the fuse
displaces a wire by which the pellet is retained substantially as described in respect
to the Figures 1 and 2.
3. A fuse in which the bending or deformation of the fuse case or base of the fuse,
causes a spring clip to open and thereby releases the pellet substantially as described
in respect to the Figures 3 and 4.
4. A fuse in which a part attached to the fuse case or base of the fuse is moved
away from the pellet and the pellet is so set free when the fuse case or base of the
fuse is bent or deformed by the pressure of the powder gases substantially as
described in respect to Figure 5.
Dated this 20th day of March 1891
K. K. MALMSTRÖM.