Improvements in Percussion Fuzes for Explosive Projectiles or Shells.
Year: 1896

page_text: Date of Application, 24th June, 1896
Complete Specification Left. 19th Feb., 1897-Accepted. 10th Apr., 1897
PROVISIONAL SPECIFICATION.
Improvements in Percussion Fuzes for Explosive Projectiles or
Shells.
We, FREDERICK MARTEN HALE, General Manager of The New Explosives
Company, Limited, of 75 Queen Victoria Street in the City of London, and
JOHN BRODIE REAVIL of 218, Woolwich Road, Charlton, in the County of
to be as
Kent, Engineer, do hereby declare the nature of this invention
follows:
.
This invention relates to improvements in percussion fuzes for explosive
projectiles or shells, the said fuzes being specially suitable for use with high
explosives.
According to our invention the fuze body is provided with an internal percussion
pellet having a detonator and with a movable portion or plunger likewise having a
detonator and carrying a transversely arranged bolt. This bolt is furnished with a
point or needle which normally occupies such a position that it lies out of the
path of the detonator in the percussion pellet. On shock of discharge the said
movable portion or plunger moves inwardly a sufficient distance to bring the end
of the said transverse bolt opposite a lateral recess in the wall of the. fuze body.
The shell in its flight and spin causes the said transverse bolt to shift radially under
the action. of centrifugal force and to enter the aforesaid lateral recess thereby
bringing the point or needle in alignment with the detonator on the percussion
pellet.
The shock of discharge also releases the percussion pellet so that on impact of
the shell the said pellet collides with the point or needle and explosion of the shell
ensues.
A spring controlled pin, or other suitable means, is provided for preventing the
said transverse bolt from shifting its position after it has entered the aforesaid
lateral recess.
The aforesaid plunger is normally retained in its outward position by an annular
guard or ferrule which rests at its lower or inner edge on a copper or other suitable
washer which offers sufficient resistance to prevent the plunger from accidentally
shifting inwardly. On shock of discharge the edge of this copper washer becomes
bent and allows the annular guard or ferrule and the said plunger to shift inward.
For releasing the percussion pellet we may employ conically pointed pins arranged
at right angles and with their points in proximity to one another. One of these
pins is situated longitudinally beneath the annular guard or ferrule and the other
pin engages with a recess in the said pellet. On shock of discharge the conical
point of the longitudinal pin is driven against the conical point of the other pin
whereby the latter (which is spring controlled) is caused to come out of engage-
ment with the aforesaid recess in the pellet whereby the said pellet is released
and is at liberty to fly forward against the firing point or needle on impact.
We may employ a spring for counteracting any tendency of the released
percussion pellet to strike the aforesaid firing point or needle under the influence
of gravity during the flight of the shell.
Our improved fuze may be applied to the explosive projectile or shell either
at its base or its

page_text: We may employ in conjunction with our fuze a primer of wet gun-cotton
when the said fuze is intended for use with shells containing a charge of wet
gun-cotton.
In some instances the detonator in the plunger may be dispensed with.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant
Improvements in Percussion Fuzes for Explosive Projectiles or
Shells.
We, FREDERICK MARTEN HALE, General Manager of The New Explosives
Company, Limited, of 7 Queen Victoria Street, in the City of Lonlon, and
JOHN BRODIE REAVIL, of 218 Woolwich Road, Charlton, in the County of
Kent, 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 relates to improvements in percussion fuzes for explosive
projectiles or shells, the said fuzes being specially suitable for use with high
explosives.
According to our invention the fuze body is provided with an internal percussion
pellet having a detonator and with a movable portion or plunger carrying a
transversely arranged bolt. This bolt is furnished with a firing point or needle
which normally occupies such a position that it lies out of the path of the detonator in
the percussion pellet. On shock of discharge the said movable portion or plunger
moves into a position to bring the end of the said transverse bolt opposite a lateral
recess in the wall of the fuze-body. The shell in its flight and spin causes the
said transverse bolt to shift radially under the action of centrifugal force and to
enter the aforesaid lateral recess, thereby bringing the point or needle in alignment
with the detonator in the percussion pellet. The shock of discharge also releases
the percussion pellet so that on impact of the shell the said pellet strikes the point
or needle and explosion of the shell ensues.
In order that our said invention may be clearly understood and readily carried
into effect we will describe the same more fully with reference to the accompanying
drawings, in which we have illustrated our improved fuze adapted to be applied to
the base of a shell charged with some high explosive such as gun-cotton.
Figure 1 is a central longitudinal section shewing the internal parts of the fuze
in an inactive position, that is to say in the position they occupy before the shell is
discbarged from a gun.
Figure 2 is a similar sectional view but shews the parts in the position they
occupy during the flight of the shell.
Figure 3 is a transverse section taken substantially on the line 1. 1. of Figure 2,
and
Figure 4.is a transverse section taken on the line 2. 2 of the same figure.
Figure 5 is an elevation of the percussion pellet.
In all these figures like letters of reference indicate similar parts.
A is the body of the fuze; B the percussion pellet; and Ċ the plunger. The
said body is provided with external screw threads to enable the fuze to be connected
to the shell in the ordinary manner, and when the fuze is intended for use with a
shell containing a charge of gun-cotton, we provide it with a cylindrical tube or
casing A containing a primer of dry gun-cotton. A is a felt disc or washer

page_text: which is interposed between the gun cotton in the said primer and the plunger C
of the fuze.
The aforesaid plunger C is formed with a neck e which is made hollow to contain
a detonator c and is provided with a removable cap e for enabling the said
detonator to be inserted in place. This cap is perforated to enable the flame from
the detonator e' to reach the primer. Situated transversely within the plunger is
a bolt C¹ having a weighted end or head C and carrying a point or needle C
which normally occupies an excentric position relatively to the longitudinal axis of
the fuze, as shewn in Figure 1. Formed in the wall of the fuze-body is a lateral
recess a which is so arranged that when the plunger moves toward the base of the
shell on shock of discharge, the head of the transverse bolt comes opposite the
lateral recess and enters this recess under the action of centrifugal force to which
the said bolt is subjected by the spin of the shell. This movement of the bolt Cr
brings the needle C in alignment with the detonator carried by the percussion
pellet B, as shewn in Figure 2. In order to prevent the said bolt C' from shifting
its position after moving transversely as above stated, we provide a pin C which
is located in a hole at right angles to the tail of the bolt C, towards which it is
kept constantly pressed by a spring. Between the lower end of the said pin and
the bolt (we interpose a steel ball C* so that the friction between the bolt and
the pin C is reduced to a minimum and the movement of the said bolt retarded as
little as possible. When therefore the tail of the said bolt is removed from
proximity to this pin and ball, the latter promptly move into the space behind the
said tail and firmly lock the bolt in its new po sition. (Figure 2.)
Immediately in rear of the plunger C is an annular ferrule or guard D which
surrounds the front portion of the percussion pellet B and rests against an annular
flexible washer or collapsible diaphragm 6 advantageously composed of copper.
This washer or diaphragm is firmly connected to the pellet B at its inner circum-
ference, but its outer circumference is free and unsupported and covers an annular
cavity or recess a¹ in the fuze body (see Figure 1). The said washer or diaphragm
is of sufficient strength to prevent the plunger C and ferrule D from shifting
longitudinally under ordinary circumstances, but on shock of discharge it collapses.
and bends around the shoulder 6x on the pellet B, as shewn at Figure 2, and
thereby allows the said ferrule and plunger to shift into the position indicated in
this figure. It will be observed that the edge d of the ferrule is somewhat.
increased in thickness, so that when this thickened edge passes the bent washer or
diaphragm, the edge of the latter will aid in preventing the ferrule from rebounding
and driving the plunger into its forward position again, before the bolt C¹ has time
to enter its reces- a. To further reduce the tendency of the ferrule to rebound,
we provide at the bottom of the cavity a' a lead washer a³ against which the end d
of the ferrule will strike.
The base of the aforesaid pellet B has a transverse slot 6' therein and the fuze-
body is provided with a transverse pin a' which fits the said slot 6'. This pin has
a bead as and the end of the slot that lies contiguous thereto, is recessed to
receive this head a³. A spiral spring a acts upon the pin a' and normally tends
to keep it in the position represented in Figure 1, that is to say with its head
in engagement with the recessed end 62 of the slot. So long as the pin is in this
position the percussion pellet remains firmly locked to the base of the fuze-body.
When, however, the aforesaid plunger C and ferrule D shift, on shock of discharge.
as above stated, a pin a' is displaced in a direction at right angles to the axis of
the said pin a. The contiguous ends of these pins a' a' are conically formed, and
therefore as the pin a' performs its movement, it drives the pin a' out of its path
and in so doing causes the head as of the pin a to be disengaged from the recessed
end of the pellet (see Figure 2). The pellet is thus disconnected from the fuze-
body and is only kept from striking against the needle C3 by a spring D', interposed
between the pellet B and the plunger C. On impact, the momentum of the pellet
overcomes the resistance of this spring and the detonator therefore strikes the
aforesaid needle and explodes. The flame thereby produced passes, by the

page_text: passage C, to the detonator c¹ which in its turn explodes and ignites the gun-
cotton in the primer A' and explosion of the entire charge in the shell ensues.
The aforesaid spring acts to prevent the percussion pellet from prematurely
striking the firing needle after the release of the said pellet.
A3 A3 (Figure 3) are transverse pins which pass through the fuze body and
enter longitudinal slots formed in the plunger. Rotary movement of the plunger
is thereby prevented and the extent of its longitudinal movement is limited by the
length of such slots, so that a correct coincidence of the head of the transverse
bolt with the recess a is ensured when the plunger shifts longitudinally on shock of
discharge.
It will be evident that by constructing a fuze in accordance with our invention,
not only must the plunger shift a sufficient distance to bring the transverse bolt
opposite the recess a and release the percussion pellet, but the said transverse bolt
must also shift laterally to bring its firing needle in the path of the detonator in
the pellet, and furthermore the resistance of the spring D' must be overcome
before the said detonator can strike the said firing needle. Consequently the
liability of the fuze to be unintentionally rendered active is very remote,
as the aforesaid movements can only be performed by discharging the shell
from a gun.
Although we have illustrated a fuze adapted to be applied to the base of an
explosive projectile or shell, it will be apparent that we can by making obvious
alterations apply it to the nose of a shell.
When the shell does not contain a gun-cotton charge, we may dispense with the
primer A' and the detonator c', and depend on the flash produced by the detonator 6³
alone for exploding the shell.
For the purpose of overcoming the difficulty that would arise in the event of the
transverse bolt C¹ not promptly entering the recess to lock the plunger in its
shifted position immediately the said plunger moves on shock of discharge, we may
provide, in the wall of the fuze body, holes or recesses C, and in the plunger,
spring controlled pins C' as shewn at Figure 3, so that as soon as these parts come
opposite each other the pins will instantly snap into the holes and lock the plunger.
Or instead of these pins we may locate a light spring at the tail end of the
transverse bolt which spring would serve to force the bolt into the recess a
irrespective of centrifugal force.
Without these pins or the said spring, the spiral spring D', when compressed
by the moving plunger on shock of discharge, might have time enough to re-act
and return the plunger to its original position before the shell had received
sufficient spin to enable the centrifugal force to drive the transverse bolt into the
recess a.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. A percussion fuze in which the firing point or needle lies out of the path of
the detonator in the percussion pellet until acted upon, by the shock of discharge
and centrifugal force or a spring, substantially as described.
2. In a percussion fuze, a movable portion or plunger provided with a transverse
bolt carrying a firing point or needle, the said bolt being so arranged that on shock
of discharge its head arrives opposite a recess in the wall of the fuze-body into
which the said head enters under the action of centrifugal force during the flight
of the shell substantially as described and for the purpose specified.
3. The combination with the transverse bolt of a spring controlled pin and ball
for locking the bolt in its outward position substantially as described.
4. The combination with the movable portion or plunger and its transversely
moving bolt of a percussiou pellet which remains locked to the fuze-body until
released by the movement of the aforesaid plunger on shock of discharge
substantially as described.

page_text: 5. The flexible washer or collapsible diaphragm acting substantially as described
and for the purpose specified.
6. A percussion fuze constructed substantially as described with reference to the
accompanying drawings, so that its action depends upon the longitudinal movement
of a plunger, the transverse movement of a bolt carrying a firing needle, the
collapse of a flexible diaphragm, the release of a percussion pellet carrying a
detonator and the compression of a spring.
Dated this 19th day of February 1897.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.