Year: 1886

page_text: Date of Application, 2nd Sept., 1886.
Complete Left, 31st May, 1887.
Complete Accepted, 1st July, 1887.
I THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster Civil
Engineer do hereby declare the nature of this invention to be as follows:-
The object of this invention is to make a base fuze which is safe in handling and in
which the pressure of the gases in the bore of the gun frees the pellet which
nevertheless is not ready to come forward and burst the shell until after the shell has
left the muzzle of the gun.
I make the outside body of the fuze in steel or other suitable metal and line it with
a bush in gun metal or other suitable metal provided with a cannelure lengthways
from which starts a groove somewhat inclined and passing partly around the bush.
At the end of this groove a hole is drilled through the body of the fuze. The hole
also passes through a longitudinal bolt contained in a chamber formed to receive it in
the body of the fuze. This chamber is open at the base so that the pressure of the
gases may act directly on the bolt. There is a hole through the bolt corresponding
with the hole in the body of the fuze.
The pellet occupies the space within the bush; it is of gun metal or other suitable
material and has a lug on one side. The lug is received into the groove in the bush
and it is tapped in the centre to receive a screw which being inserted through the hole
in the side of the body and through the bolt retains the pellet until the gun is fired.
When the shell is fired in the gun the pressure of the gases acting on the bolt
thrusts it forward and cuts the screw which secures it to the pellet. The pellet is now
free to rotate but cannot come forward until the movement of the shot brings the lug
to the longitudinal cannelure.
The length and direction of the circular groove can be so regulated that the lug on
the pellet will not reach the end until the shell has left the muzzle.
When the lug is in the longitudinal cannelure the pellet is free to come forward
when the flight of the shell is checked by impact. The pellet has a recess on its top
filled with detonating composition which when the pellet comes forward strikes against
a needle point and so fires and bursts the shell.
The weight of the pellet can be so regulated as required. .
Dated this 2nd dov of Santambon 1006

page_text: I, THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster
Civil 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 :-
The invention relates to fuzes to be applied to the base of a projectile.
The improvements have mainly for their object to make an efficient fuze possessing
the following qualities
:-
1. That it shall be perfectly safe in handling so that no concussion or shaking
can set it into action.
2. That the pellet shall be set free by the pressure of the gases in the bore of
the gun.
3. That the pellet although set free shall be unable to come forward and burst the
shell until the shell has left the muzzle of the gun.
I obtain these results in the following manner :-I liberate the pellet at the time
when the projectile is fired from a gun by causing the pressure of the powder gases
to thrust forward a bolt to shear off a pin by which the pellet was previously held
fast. In addition I render it impossible for the pellet when so liberated to fly forwards
whilst the projectile is within the gun by forming the pellet with a side lug or
projection to lie in a groove which is at right angles or inclined to the longitudinal
axis of the projectile. As the projectile rotates the lug passes along this groove and
when the projectile has left the gun it enters a groove formed lengthwise of the body
of the fuze and is then free to fly forwards whenever the forward movement of the
projectile is arrested or checked.
The drawings hereunto annexed shew various views of a percussion fuze formed as
above described.
Figure 1 is a longitudinal section of the fuze ready for use. Figure 2 is a similar
section of the fuze at the time when the bolt has been forced forwards by the pressure
of the powder gases leaving the pellet free to turn but not to fly forwards.
Figures 3 and 4 show the fuze at the time when the projectile has left the gun and
the pellet is free to fly forwards. Figure 5 shows the fuze at the time when the flight
of the projectile has been arrested and the pellet thrown forwards and about to fire
the charge of the shell. Figure 6 is a transverse section through the line A B,
Figure 1. Figure 7 is a transverse section through the line CD Figures 3 and 4 and
Figure 8 a transverse section through the line E F Figure 5.
A is the body of the fuze in steel or brass or other suitable metal. B is a
cylindrical lining placed within the interior of the body and retained therein by a screw
ring C-this cylindrical lining I by preference form of steel. Through the lining is
formed a longitudinal slot D having a slot E branching from it this branch slot is
shewn to be inclined to the longitudinal axis of the fuze. F is the pellet formed with
a lug G projecting from its side to enter these slots. H is a pin passed through the
side of the body and screwed into the lug G. The pin H also passes through a steel
bolt I this bolt lies within a hole J formed longitudinally in the body A close to one
side of its hollow central chamber. The rear end of the hole J is open so that the
pressure of the powder gases may get to the rear end of the bolt and force it
forwards. Copper cups or lead washers or any other forms of gas checks K are

page_text: usel to prevent the powder gases from getting past the bolt. A single cup may be
used or a pair of cups one in rear of the other may be used as preferred.
When the powder gases force forwards the bolt I the bolt shears the pin H as
shown at Figure 2. Afterwards as the projectile rotates the lug G of the pellet passes
along the inclined slot E and into the longitudinal slot D as shown at Figures 2 and 3
so that the pellet may be free to fly forward when the flight of the projectile is
arrested.
The length and the disposition of the circular groove can be so regulated that the
lug G on the pellet will not reach the end of the slot E until the projectile has left the
muzzle of the gun. The pellet as usual carries a patch of fulminate L which detonates
when it comes against the point M.
It will be seen that the pellet can be made of any weight so that a shell of any
size can be made as sensitive as may be desired without in any way making the fuze
dangerous.
In the drawings I have only shown my improvements applied to percussion fuzes-
but a time fuze may be formed in a similar manner that is to say the lighting of the
fuze may be effected by a pellet which is liberated by the pressure of the powder gases
acting on the rear end of a bolt to force it forwards and by shearing a pin liberate
the pellet which however is not free to fly back and fire the fuze until the projectile
leaves the gun.
Such fuzes could also be made to act both as a time fuze and percussion fuze so that
in case of the failure of the time fuze or the flight of the projectile being arrested
before the time fuze has acted that the shell may be exploded immediately on its
encountering any obstacle.
The action of the percussion fuzes in igniting the charge of the shell may also be
delayed whenever it is desired that their action shall be comparatively slow by filling
part of the passage by which the flash from the patch of fulminate L passes to
the charge in the shell with powder highly compressed and which will burn
comparatively slowly. Two ways of effecting this are shown at Figures 9 and 10.
In Figure 9 the point M is as in the fuzes shown in the other figures carried by the
ring C. In Figure 10 the patch of fulminate L is carried by the ring and the point
is carried by the pellet. In each figure the block of highly compressed powder is
marked O. In this way the fuze can either be changed from a direct action fuze to a
delayed action fuze simply by changing from one form of the ring () to the other.
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 I claim is :-
1. A fuze in which the pellet has to be set free by the pressure of the powder gases
in the bore of the gun and is then unable to fly forwards and fire or ignite the fuze
until the shell has left the muzzle of the gun.
2. The combination of the body A, the cylindrical lining B having in it slots D
and E, the pellet F having a lug G projecting from it to enter the slots, the pin H
retaining the pellet, the bolt I through which the pin H passes and which has to be
pressed forwards by the pressure of the powder gases to cause it to shear the pin
substantially as described.
3. A fuze with the pellet retained by a bolt which works in a cavity formed
longitudinally in the body and with a cup or gas check in the mouth of this cavity to
prevent the powder gases from passing the bolt.
4. The construction of fuzes substantially as herein before described and illustrated
in the drawings annexed.