Improvements relating to Explosive Projectiles or Shells and Torpedoes, and to Cartridges or Charges for Use therein.
Year: 1895

page_text: Date of Application, 5th Dec., 1895
Complete Specification Left, 4th Sept., 1896-Accepted, 10th Oct.,
1896
PROVISIONAL SPECIFICATION.
Improvements relating to Explosive Projectiles or Shells and
Torpedoes, and to Cartridges or Charges for Use therein.
I, HENRY JACKSON WELLS DAM, of The Lindens, Abbey Road, London,
N.W., Dramatic Author, do hereby declare the nature of this invention to be as
follows:-
The object of my invention is to provide in a more efficient manner than
heretofore for the safe use of nitro-glycerine and other high explosives in armour-
piercing and other explosive projectiles or shells and torpedoes.
It is well known that the great objection to the use of high explosives in shells
is their liability to be accidentally exploded either by the shock or concussion due
to the impulse imparted to the projectile when the powder-charge is fired, or by
that due to the sudden rotation of the projectile when it enters the rifling of the
gun, or, in the case of armour-piercing shells, by the shock or concussion due to
impact. And various improvements have been devised to overcome this objection,
but without any very satisfactory results.
Now according to my invention I provide in a very simple and effectual manner
for preventing the transmission of any dangerous shock or concussion to the
explosive material or charge of the projectile or shell either while the said
projectile or shell is being discharged from a gun, or, in the case of armour-
piercing shells, upon impact. And I also, by my invention, diminish the liability
to accidental explosion of such projectiles or charges during storage, handling or
transport.
For this purpose I enclose the explosive charge in a case or receptacle of metal
or other suitable material and I enclose this case or receptacle in a series of
protective cases or tubes of metal, wood or other suitable material, each case or
tube being of so much greater length than the one it encloses as to leave a suitable
air-space between them at either end.
These cases are so constructed that, when the projectile is driven forward or
when it strikes an object, the said cases will slide one within the other in alternately
opposite directions. Each case is open at one end and is closed (air-tight) at the
other and in any two adjoining cases the closed ends are at opposite ends of the
cartridge. The result is that the backward movement of the outermost case
instantly causes a forward movement of the next case which in turn causes &
backward movement of the next case and so on, thus constituting a series of air-
cushions between the case containing the explosive charge and the outer protective
case, and also an air-cushion at either end of the innermost case.
In this
The said cases are fitted closely one within another, and between the said cases
I insert a suitable packing or lubricating material such as grease of some kind, or
blacklead, or I provide other suitable means whereby an approximately air-tight
joint will be formed between each case and the case which it encloses.
manner I ensure that the inertia of the charge shall be very gradually overcome
both when the projectile or shell is discharged from the gun and upon impact, as
the movement of either of the enclosed cases in either direction relatively to the
case in which it is enclosed, causes a compression of the series of air-cushions and a
rarefaction of the air in one end of the outermost case.
I can, if desired, close the several protective cases at both ends; I prefer
however to close them at one end only as above mentioned.

page_text: I also provide for preventing rotation of the charge with the projectile or shell
when the latter enters the rifling, or for ensuring that the inertia of the charge
shall be very gradually overcome when the projectile or shell is rotated. For this
purpose I sometimes make the exterior protective case with a conical, pointed or
other suitable pivot or bearing at each end whereby it is supported at its ends
centrally in the projectile or shell in such a manner that it is free to rotate
relatively thereto, and is out of contact with the inner wall of the projectile or
shell.
I sometimes surround the outermost or any of the other cases with suitable
non-conducting material to prevent the transmission of heat to the charge.
My improvements are applicable in a similar manner to torpedoes.
Dated the 5th day of December 1895.
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.Ċ.,
Agents for the Applicant.
Improvements relating to Explosive Projectiles or Shells and
Torpedoes, and to Cartridges or Charges for Use therein.
1, HENRY JACKSON WELLS DAM, of The Lindens, Abbey Road, London,
N.W., Dramatic Author, do hereby declare the nature of this invention and in what
manner the same to be performed, to be particularly described and ascertained
in and by the following statement :—
The object of my invention is to provide in a more efficient manner than
heretofore for the safe and successful firing, from service rifled and smooth-bore
guns with service charges of powder, of high explosives, such as blasting-gelatine,
in armour-piercing and other shells.
By my said invention, however, I also provide for the safe storage, transport and
handling of high explosive charges for such shells.
It is well known that the great objection to the use of high explosives in shells
is their liability to prematurely explode.
The causes of premature explosion when such shells are shot from service
ordnance with service charges are as follows:-
1. The shock or concussion due to the forward impulse imparted to the shell
when the powder-charge is fired.
2. The sudden rotation of the projectile when it enters the rifling of the gun,
and its rotation during flight.
3. Lateral vibration of the shell in the gun, and
4. In the case of armour-piercing shells, the shock or concussion due to impact,
whereby the shell is exploded before it can pierce the armour.
Various improvements have been devised to obviate the liability to premature
explosion from these causes, but, as far as I know, without any very satisfactory
results.
Now according to my invention I accomplish the desired object in a very simple
and effectual manner as hereinafter described.
I obviate the first and fourth of these causes of accidental explosion, viz. :-
shock and impact, as follows:-I enclose the explosive charge in a cylindrical case
having very thin walls, which case is the innermost of a series of thin concentric
sliding cases. These cases slide upon one another in alternately opposite directions
or in other words telescope together. This telescoping is caused by the successive
compressions of air in air-tight spaces left at both ends of each case. The shock
of firing is thus received on a series of air-cushions and largely absorbed in friction

page_text: and compression before it reaches the explosive charge, which in addition has air-
cushions at either end. And, as will be seen from the drawing (Figure 1), the
explosive charge when fired from the gun is so far removed from shock that it
remains practically in statu quo with relation to the shell itself, the series of cases
enclosing it alone moving backward and forward around it in succession and
receiving and absorbing so much of the concussion that the remainder ceases to be
an element of danger. Similarly upon impact against armour the series of cushions
will act in the same way in the opposite direction.
The second cause of premature explosion, viz. :-rotation, I obviate by preventing
the rotation of the explosive charge. This is done by enclosing the series of
telescoping cases in an outer case which is supported in the shell by central pivots
at its ends so that the said outer case is out of contact with the shell except at the
pivots. The shell when rotated will thus very slowly and imperfectly, if at all,
impart rotation to the charge-case. When it is necessary to prevent even such
imperfect rotation of the charge-case, I make spiral grooves on the interior of the
shell-walls and also on the outer surface of the outer case so that the rotation of
the shell in one direction will, through the action of the air, prevent rotation of the
said case with the shell or impart a very slight rotation to the said case in the
opposite direction.
The third cause, viz.:-lateral vibration of the shell when being driven out of
the gun, I obviate by placing a cushion or cushions of air or of india-rubber
between the bearings on which the pivots turn and the shell itself, which cushions
will diminish the jarring from lateral vibration to a point where it becomes
negligeable and will also reduce the rigidity with which the case is held in position
and thus diminish the rotatory friction on the pivots. I also place a ring of soft
india-rubber on the pivots to neutralize any possible vibration which may be
imparted by contact of the said pivots with the sides of the bearings.
The said cases are made to fit closely one within another, and between the said
cases I insert, if necessary, a suitable packing or lubricating material such as
grease, or black-lead, or I provide other suitable means, such as greased packing,
whereby an approximately air-tight joint will be formed between each case and the
case which it encloses. The friction produced by the cases sliding on one another
is the lowest amount consistent with keeping the joints reasonably air-tight. In
this manner I ensure that the inertia of the charge shall be very gradually
overcome both when the projectile or shell is discharged from the gun and upon
impact, since the movements of the enclosed cases in either direction cause a
compression of the series of air-cushions and a rarefaction of the air in one end of
either the outermost or innermost case.
In the accompanying drawing
-
Figure 1 is a longitudinal central section of a common forged steel shell having
my improvements applied thereto.
Figure 2 is a longitudinal central section showing a shell constructed according
to my invention for use with a smooth bore gun, and
Figure 3 is a section on the line x, 2, Figure 2.
A is the shell which is provided with a removable base A' and with a removable
cap or plug A2 at its apex. B is a case of metal or other suitable material, which
is filled with blasting-gelatine or other high explosive suitable for the purpose of
my invention, preferably in such a manner as to ensure the exclusion of air from
the said case.
This charge-case is closed at both ends and is enclosed in a series
of protective cases C, D, E and F, which, with the exception of the outermost
one F, are closed at one end and open at the other, and are arranged with their
open ends alternately at either end of the shell. The outermost protective
case F is closed at both ends and is supported within the shell A by
pivots f,f¹ at its ends so that it and the shell can rotate freely relatively to each
other.
1
The charge-case B is fitted in the case C so that it can slide longitudinally
therein, and the cases C, D and E are similarly fitted in the cases D, E and F

page_text: respectively, suitable packing being provided, if necessary, to prevent or control
the passage of air between the said cases from one end to the other. An air-
space a is left between the forward end of the case B and the forward end of the
case C, and an air-space 6 between the rear ends of the cases B and C and the rear
end of the case D. In a similar manner an air-space c is left between the forward
ends of the cases C and D and the forward end of the case E, and an air-space d
between the rear ends of the cases D and E and the rear end of the case F. One
end of the outermost case F is screwed in or otherwise made removable so that the
inner cases can be introduced into the said outermost case.
It will be seen that, by the arrangement above described, a series of successive
air-cushions is provided so that, when the shell is driven forward by the powder-
charge, relatively to the case E, the air in the spaces b and d will be compressed
and a partial vacuum will be formed between the forward end of the case E and
the forward end of the case F, and also between the innermost case B and the
forward end of the case C. The compression of the air in d will cause the case D
and its contents to rebound or move forward in the case E and thus compress the
air in the space c, which compression will in turn cause the case C and its contents
to move backward in the case D. The air in b will be further compressed by such
backward movement and will cause the charge-case B to rebound or move
forward in the case C and thus compress the air in a. A very efficient
cushioning of the explosive charge is thus ensured, obviating all liability to
explosion of the said charge by the shock or concussion due to the sudden
forward movement of the shell and the inertia of the enclosed charge and its
protective tubes or cases.
I can use any suitable fuse, primer or detonator for effecting the explosion of
the bursting-charge at the proper time.
In the drawing I have shown a revolver-cartridge e inserted in a tube g attached
to the case F, with its bullet-end towards the bursting-charge in the case B, and
held securely in place by means of an inner tube g¹, the pivot f¹ being prolonged
as at 2 to form a firing-pin or striker, and being retained in position by means of a
nut of lead or other suitable material. Upon impact, the case F and its contents,
being driven forward relatively to the shell by their momentum, strip the thread
from the nut and cause the priming of the cartridge e to strike the firing-pin f²,
so that the bullet of the said cartridge is shot into the bursting-charge of the shell
and causes the explosion thereof.
To diminish the jarring due to vibration of the shell, I mount the pivot-pins f, f¹
in bearings, which are supported by soft india-rubber cushions 2, 3; and I also
place a ring of soft india-rubber around each of the said pivot-pins so as to form
a cushion between it and the sides of the metal bearing to prevent their touching
each other.
To more effectually prevent rotation of the case F and its contents with the
shell, I sometimes form spiral ribs, grooves or corrugations on the interior of the
wall of the shell and on the exterior periphery of the case F in such a manner
that the rotation of the shell about its axis in one direction will, through the
action of the air Letween the said case and the shell, tend to prevent rotation of
the case For to cause it to rotate slowly in the reverse direction.
To keep the sliding cases in their proper position relatively to the enclosing
case F until the shell is fired from the gun, I affix to the inner wall of the case F,
by means of glue or shellac or the like, supports of india-rubber or other suitable
material, which will hold the cases D and E in position but will break off, leaving
a smooth surface, when the case F is driven forward with the shell-body relatively
to the enclosed cases upon firing. Or I provide other suitable devices for
accomplishing this result. The inner cases will be held in their proper relative
position through friction and the elasticity of the air, until the air-cushions are
compressed as above described.
My improvements are applicable in a substantially similar manner to torpedoes
carrying a very sensitive explosive.

page_text: In applying my improvements to armour-piercing shells, I provide the shen wich
a suitable time and percussion fuse so that the said fuse will be set in action upon
impact but will not operate to cause the bursting of the shell until a predetermined
period has elapsed, thus allowing time for the shell to penetrate or pass through
the armour before it is burst. I can, if desired, adapt for this purpose a fuse such
as that shown in the drawing by making a part of its charge from slow-burning
instead of from quick-burning powder.
In making an explosive projectile or shell in accordance with my invention for
use with a smooth bore gun, I make the same very long in proportion to its diameter
as shown, for example, in Figure 2. In this case, as there is no rotation of the
shell, I dispense with the outer pivoted case and arrange the outer longitudinally
sliding case E within a suitable cavity in the shell A. Moreover I provide the
shell with four or any other suitable number of ribs or fins k formed by making
longitudinal grooves in the shell-body, so as to leave a rib between two grooves as
shown in Figure 3. These ribs or fins ensure steadiness and accuracy of flight.
In the shell shown, the exploding device consists of a small-arm cartridge e held in
a cavity in the base A¹ of the shell and arranged to be fired, upon impact, by a
plunger having a firing-pin or striker and held back, under ordinary circum-
stances, by a pin m, which, upon impact, is broken off by reason of the momentum
of the plunger l.
Having now particularly described and ascertained the nature of my said inven-
tion, I wish it to be understood that I am aware that it is not new to construct a
shell with a separate longitudinally sliding case or receptacle for the bursting-
charge so arranged in the said shell that there is, between the rear end of the said
case and the base of the shell, a cushiou of air which will absorb some of the force
of the shock or concussion produced when the shell is driven forward in a gun, and
will thus diminish the force of the shock imparted to the charge-case; and I make
no claim to such form of construction. I am also aware that it has been.
proposed to make a shell with a longitudinally sliding case having within it a
receptacle for the bursting-charge which is free to turn about its longitudinal
axis; and I make no claim to a shell so constructed. But I declare that what I
claim is :-
1. An explosive projectile or shell or torpedo wherein the bursting-charge is
enclosed in a tube or case which is itself enclosed in sliding protective tubes or
cases arranged one within another with a series of air-cushions between the inner-
most and the outermost cases at the ends thereof, substantially as herein before.
described and for the purpose specified.
2. An explosive projectile or shell in which the bursting-charge is enclosed with
air-cushions at its ends in a case which is pivotally supported in the shell, its wall
or periphery being out of contact therewith, substantially as herein before described
and for the purposes specified.
3. The combination, with a shell, of a case supported therein by pivots at its.
ends, its wall or periphery being out of contact therewith, and longitudinally
sliding cases contained in the said pivoted case and enclosed one within another,
the innermost sliding case containing the bursting charge, for the purposes above
specified.
4. An explosive projectile or shell or torpedo, comprising longitudinally sliding
protective tubes or cases open at one end and closed at the other end, arranged
one within another, and a longitudinally sliding charge-case enclosed in the inner-
most protective case, all being so arranged as to leave air-cushions between the
ends of the several cases, substantially as hereinbefore described and for the
purposes specified.
5. A burster-case for an explosive projectile or shell or torpedo, provided with.
central end-pivots, longitudinally sliding protective tubes or cases arranged one
within another and enclosed in said burster-case, and a longitudinally sliding
charge-case enclosed in the innermost protective case, air-cushions being provided

page_text: at the ends between said cases, substantially as hereinbefore described and for the
purposes specified.
Dated the 4th day of Sentember 1896.
H. J. W. DAM.
D. Young & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicant.