IMPROVEMENTS IN THE CONSTRUCTION AND MANUFACTURE OF ORDNANCE, AND IN APPARATUS TO BE USED FOR THE SAME
Year: 1885

page_text: I, JAMES ATKINSON LONGRIDGE of 15 Great George Street in the City of
Westminster, Civil Engineer, do hereby declare the nature of my invention for
IMPROVEMENTS IN THE CONSTRUCTION AND MANUFACTURE OF ORDNANCE, AND
IN APPARATUS TO BE USED FOR THE SAME, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The first part of my Invention of Improvements relates to the construction of
the barrel of a wire gun.
•
Instead of the steel core or tube generally used on which the wire is coiled,
I employ a core or tube of cast iron or other material having a low modulus of
elasticity, but in order to carry the rifling and to protect the core from abrasion
by the gases, and also in order to render the repairs of the gun easy and
inexpensive when the rifle grooves are too much worn to be renewable, I introduce
a thin lining inside the core, which lining is made either of hard steel or very hard
cast-iron. This tube is put in with a slight amount of shrinkage, and when it has
to be replaced this is done by heating the outside of the gun when the expansion
of the core allows the lining to be withdrawn and replaced by a new one.
I do not claim the introduction of a thin lining into guns generally, but only in
the case of wire guns made with a soft and yielding core and the object is two-fold,
first to facilitate the repairs of the gun when worn, but mainly to enable a greater
force of compression to be given by the coil than could otherwise be done, the thin
inner tube or lining which has a high modulus of elasticity taking on itself the
extreme compression which would otherwise come upon the inner surface of
the core.
Also when the gun is under fire the maximum tension which would otherwise
come upon the inner surface of the core is borne by the thin lining which has
a high modulus of elasticity and elastic limit, and thus a stronger gun can be made
with the same weight of material than could otherwise be done.
My second improvement relates to and has for its object the better provision for
and equalization of the strains and especially the longitudinal strains in that part
of a piece of ordnance situated behind or to the rear of the Trunnions or in lack
of Trunnions, the saddle, whereby the core is connected with its bed or carriage.

page_text: transmitted through the Chase or Jacket to the Trunnions thus inducing a
longitudinal strain in that part of the Chase or Jacket; but this strain is not, in
guns as now constructed uniformly distributed over the sectional area of the
material, it is greatest in that portion which is nearest the longitudinal axis of the
gun and gradually decreases as the distance from the same increases, consequently
the longitudinal and the transverse strains are both combined at their respective
maxima to rupture the gun.
The object of this improvement is to relieve the inner portions of the Chase or
Jacket from longitudinal strains to such extent as may be desirable, throwing at
the same time such strain on such portions of it as may be desirable on the outer
material, and this I do by putting such outer material into a state of initial
longitudinal tension, at the same time that the inner material is put into a state of
initial longitudinal compression. By the terms "initial" I denote the state of the
material at rest, that is to say, when not under fire.
The method by which this is accomplished is best explained by reference to the
following drawings Sheet N° I.
Fig. I represents a portion of a muzzle loading gun either solid or built up
in rings.
A. A are the Trunnions.
B. the inner hoop or tube in a built up gun.
C. the outer hoop or tube.
H. is the barrel of a solid gun.
D. is a steel ring or hoop, the portion of it E. F. has an internal screw cut in it,
which takes the external screw cut upon the outer hoop C, and it abuts at G upon
the inner hoop B of the built up gun, and in the solid parts of the breech of a
solid gun as shewn in the lower half of the figure at G. By screwing up the ring
or hoop D it is evident that the outer part of the Chase C, will be put into tension
and the inner part B, into compression between D and the Trunnions.
Fig. 2 represents a half section of a built up Breech-loading gun in which B is
the inner tube, C the outer Hoop or Jacket and D the straining hoop, by screwing
which up B is thrown into initial compression and C into initial tension. The
arrangement shewn in Fig. 2 is also applicable to a wire gun in which the Hoops or
Rings between B and C are replaced by wire coils, but in wire guns I prefer the
arrangement shewn in Fig. 3 in which there is absolutely no longitudinal strain in
the inner tube B.
In this case an internal steel ring K in which the breech plug works is screwed
internally to the outer, tube or casing C and this straining ring or loop D bears
upon it at K. In this way the inner surface of C is placed in initial compression
and the outer surface in initial tension.
7
The functions of the ring D may be put into action either by the mechanical act
of screwing it up, or by simultaneously heating the outer surface of C and
cooling the inner surface of B and then screwing on the ring D and letting the
structure cool.
°
My third improvement relates to that part of the gun which constitutes the
inner tube which I call the core of a built up or coil gun.
It is well known that in such guns the core is put into a state of compression
by the grip of the outer tubes or coils when the gun is completed and at rest.
Now in some cases the amount of this compression would be so great that it
would exceed the elastic limit of the material, and in such cases permanent set
would take place and the calculations of the strains be vitiated and the proper
amount of abrinkage in Hooped or Laying on tension in coiled guns, rendered
difficult of determination.
The object of this part of my invention is to provide against these difficulties,
and this I do by submitting the inner tube or core to compression previously
to the outer tubes being shrunk on, or the wire coil applied. The amount of
such compression depends upon and ought to be at least equal to the maximum

page_text: compression to which the material will be subjected by the subsequent action of
'the superimposed Tubes or Coils, and this may be ascertained in each case by the
rules given in my Treatise on the Application of Wire to the Construction of
Ordnance published by E. & F. N. Spon, London and New York, 1884.
By this preliminary compression the core obtains its permanent set before being
operated on by the tubes or coils exterior to it, and the effect of such previous
compression is to extend the limit of elasticity, a phenomenon which is designated
by some writers "Special elasticity.
There are several methods by which this preliminary compression may be given
but the one which I prefer is to give it by coiling steel wire on to the core under
a considerable tension in one or more coils. In order to give any required definite
compression to the core, the number of coils to be so coiled on and their respective
tensions or strains of laying on, are to be determined by the rules and formulae
contained in my Treatise above referred to.
After the due amount of compression has been obtained these temporary coils
are taken off and the core is then ready for receiving its permanent covering of
tubes or wire coils.
My fourth improvement refers to the method of supporting the end of the wire
coil and fixing the end of the wire at the Breech end of the gun which I proceed
to describe by drawings.
Fig. 4 represents a half section of the end of the tube or core.
Fig. 5 an end view of the same.
.
In Fig. 4, A is the end of the tube or core, B is the ring or Hoop which supports
the wire coil.
•
Now if A and B were in one piece or if B were shrunk on, or screwed on to A
dangerous strains would arise both from coiling on the wire and from the action of
the powder gases.
In the former case the tube to the right of A would be
compressed by the whole force of the coil, whilst to the left of A it would not be
compressed at all, but would be reinforced by the whole strength of the ring
or hoop B.
In the latter case the Core to the right of A would be expanded by the powder
gases, whilst to the left, being behind the obturation, it would be free from their
action, and would be reinforced as before by B. In either case the tendency would
be to shear the core or tube at its junction with the Hoop or ring B.
In order to avoid this injurious action I make the ring B with a square headed
internal screw thread and on the tube A I make a corresponding square external
screw thread, making the diameter of the former somewhat greater than the
internal diameter of the latter and vice versa so that there is sufficient space for
radial expansion and contraction between the two which thus provides against the
injurious effects above described. In order to fix the ends of the coil the ring B is
under-cut at the point to the breadth of the wire at C and to a gradually
decreasing breadth round the circumference until it runs out to nothing when it
makes a complete turn.. At the point C'this under cutting is deepened in a radial
direction so as to receive the Gib or Head which is formed in the end of the wire
as shewn at C Fig. 5. Consequently the wire at this point is entirely under the
ring B, and as it is coiled on it gradually emerges until in one revolution it is clear
of the ring, and the succeeding coil abutting against it effectually prevents it
coming loose. In order to fix the other end of the wire, that is to say the end of
the last coil, the outer circumference of the ring B is partially cut away to the
depth of the thickness of the wire and to three or four times its breadth as shewn
at D, E, Fig. 4. When the last coil has reached the ring it is coiled two or three
times round the ring on the part thus cut away, and finally the end of the wire,
bent down at right angles, is inserted in a radial hole and fixed. by driving in a
key or wedge F, Fig. 5.
4
°
My fifth Improvement relates to the apparatus for coiling on the wire, in wire
guns, which I will proceed to describe.
↑

page_text: The core or inner tube on which the wire is to be coiled is supported by two or
three standards which are connected together at fixed distances from each other
and which are free to slide on a bed or frame fixed firmly to the ground, similar to
a lathe bed. The tube or core is free to revolve in these standards and it is
carried backwards or forwards by them in the line of its axis.
In the same line and in the same frame is a fixed headstock with such gearing
as may be required. The mandril of this headstock terminates in a face plate, or
chuck, to which is fixed a long shaft, one end of which reaches a little beyond the
first moveable standard and enters into the bore of the core or tube. Upon this
shaft is a moveable collar which has a key-way, fitting to a longitudinal key or
rib in the shaft, so that it is driven by the shaft and is at the same time free to
slide along it. This collar is attached to the core of the gun which consequently
revolves with it.
The moveable standard nearest to the fixed headstock is traversed along its bed
by means of a horizontal screw driven by change wheels from the mandril of the
fixed headstock, so arranged as to move the moveable standards the breadth of the
wire for each revolution of the gun tube.
The motion of this screw can be
reversed by the ordinary reversing gear so as to travel the standards backwards
or forwards as required. In this way the wire is laid on in a close coil or spiral,.
in either direction.
The wire, after leaving the original coil, passes several times backwards and
forwards over two drums which may be either plain or grooved, it then passes
over a Dynamometer pulley and from thence to the core or tube on which it is to
be coiled.
In order to give the proper amount of tension brakes are applied to the axes of
the Drums round which the wire passes. I prefer the brakes known as Appollo
brakes but other brakes, such as Prony or Deprez may be used.
The dynamometer pulley is so arranged as to vary the action of the brakes as
will be more fully explained by the drawings.
My sixth Improvement consists of a method by which the requisite laying on
Tension is obtained by the friction of the wire itself without the use of friction
brakes.
This is done by passing the wire between the original coil and the dynamometer
pulley several times round a cone, on which is cut a spiral groove in which the
wire lies. In order to give a uniform pressure of the wire on the cone and con-
sequently a uniform friction, this groove should be so cut as always to preserve the
same angle to the axis of the cone.
In this way the tension is always proportional to the length of wire in contact
with the coue, and this may be varied at will by rotating the cone round its
vertical axis.
After leaving the cone the wire passes over the dynamometer pulley and then on
to the revolving core or tube of the gun, which is carried as above described.
In all cases it is important that there shall be no reversal of the original bend of
the wire and this is provided for in both the apparatus above described.
In order that the above methods of coiling on the wire may be more clearly
.understood I now proceed to explain the drawings Sheet II which accompany this
Specification.
Fig. I is a general elevation of the gun core mounted in three moveable standards
on the bed plate which also carries the fixed Headstock and driving gear.
Fig. 2 is a ground plan of the same, shewing also the gun tubes in section.
Fig. 3 is an end elevation of one of the moveable standards on its bed with the
gun blocked in the same.
..
Fig. 4, is an end elevation of the fixed Headstock.
The same letters refer to each figure.
A A is the bed plate on which is fixed the Headstock B B carrying the ordinary
driving gear and which also naming the instable todada

page_text: DD D'is the gun core or tube, round the part of which between the first two
moveable standards the wire is to be coiled. This tube is supported in the first
standard by its flange a. a Fig. 2 which exactly fits into recesses in the guide
blocks b. b in which it 'revolves. It is also supported by and revolves in similar
guide blocks in the other moveable standards, and all these blocks are truly
adjusted to the axis of the gun.
The distance between the moveable standards depends upon the form of the gun
and when the gun is in its place, they are bolted together longitudinally so as to
preserve their distances invariable whilst the whole combination is traversed
backwards or forwards in the sliding bed.
'This traversing motion is given by the screw E E, which is connected with the
first moveable standard by a proper nut fixed to the standard through which it
passes. And the prolongation of this screw passes also through the second
standard to which it may when desirable be similarly connected. This screw is
actuated by the change wheels shewn at the left hand side of the fixed Headstock
and is also provided with the usual reversing gear for reversing its motion.
I will now describe the connection between the driving mandril of the fixed
Headstock and the gun.
a
On the end of the mandril g, is fixed a chuck or face plate, d. To this is fixed
hollow driving shaft e e also shewn in section in Fig. 2. This shaft is turned
quite true externally and is provided with a key or rib c c which acts as a driver
to the collar f & which is furnished with a corresponding groove and is turned to
the same internal diameter as the shaft; or the groove may be on the shaft and
the key on the collar. In either case the collar can slide along the shaft, and is
caused to rotate with it.
The collar is flanged at the end and exactly fits to the guide blocks b b. And it
is also fixed by screws or driving pins to the flange a, a, Fig. 2, of the gun tube.
Consequently, when the machine is in action, the gun tube is caused to revolve
with the collar on the shaft e, e, and at the same time is free to move in the
direction of its own axis backwards or forwards with its supporting standards
actuated by the screw E. The length of the shaft e, e, depends of course on the
length of coil which is to be put on the gun. As the gun tube approaches the
fixed Headstock the hollow shaft passes into the bore of the gun.
I now proceed to describe the apparatus for guiding the wire and giving the due
initial tension of laying on. And I will first describe the apparatus when this
tension is given by friction brakes.
Fig. 5 is an elevation and Fig: 6 a ground plan of this arrangement. The wire W
coming from the original coil passes several times over and under the drums A A
Fig. 5. It then passes over the dynamometer pulley B and so to the gun core or
tubes; to the axes of the drums A A are fixed friction sheaves S, S, and brakes,
and though various brakes may be used I prefer that known as Appollo's and which
is shown in Fig. 5, and which is too well known to require further description.
The amount of Tension is regulated by the weight at C Fig. 5, and the weight of
the dynamometer is adjusted to correspond. The dynamometer pully block F is
connected by levers and rods with the lever D D, so that if the friction of the
brakes should from any cause increase, the pulley block descends and the lever D is
drawn forward and relieves the weight on the Brake levers and vice versa.
G, G, Fig. 5, are water cylinders in which work Pistons connected with the Pulley
Block F and the weight C respectively so as to mitigate any sudden irregularities
of action.
The apparatus as above described is fixed a little to the rear of and at right
angles to the axis of the gun and about opposite to the centre of the coil; and it
will be seen that there is no reversal of the original bend of the wire.
I now proceed to describe the drawing Fig. 6, Sheet I, which illustrates the
sixth part of my invention. The gun tube or core is fixed in the same apparatus
as before and the wire passes over the dynamometer pulley in the same way, but
instead of passing over the drums between the original coil and the dynamometer

page_text: .
it passes round the vertical cone A A Fig. 6 in a spiral groove, and the friction of
the wire against the cone gives the required tension which depends for its amount
upon the length of wire in contact with the cone. The cone can revolve about its
vertical axis, but is fixed in any position by the worm wheel B, and the worm or
screw C which takes into its teeth. This worm is actuated by a handle so that the
attendant can by working it wind or unwind the wire on to the cone. Should the
dynamometer indicate too great a strain the attendant can at once relieve it by
rotating the cone so as to cast off part of the wire and vice versa.
The cone is kept cool by a current of water passing through it.
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. The application to wire guns with a soft or yielding core of a thin lining of
hard material such as steel or hard cast iron substantially as and for the purpose
above described.
2. The method of adjusting or equalizing the longitudinal strains arising from
the powder pressure on the breech, in that part of the Chase or Jacket which lies
between the Breech and the Trunnions or the saddle which replaces the Trunnions,
when these are not used, by means of a straining ring or Hoop screwed on substan-
tially as above described so as to put the outer material into initial tension, and
the inner into initial compression.
3. I claim the submitting the inner tube or core of a gun to a preliminary
compression force so as to give the inner portion of the material a permanent set
and thereby increase its elastic limit previously to the outer tube or wire coil being
put on, substantially as and for the purpose above described.
4. The method of fixing the supporting ring of the coil at the Breech end so as
to avoid shearing strains in the core and the method of fixing the ends of the core
to the same, substantially as above described.
5. I claim the arrangement whereby the gun core or tube is made to revolve
whilst at the same time it travels in either direction to right or left of the line of
wire which is being coiled on, such transverse motion being regulated so that the
distance traversed in each revolution is exactly equal to the width or breadth of
the wire, whilst the proper tension of the wire is obtained by friction or by friction
brakes and regulated by a Dynamometer pulley substantially as above described.
. 6. The arrangement whereby the required tension is given by the friction of the
wire passing round a spiral groove or guide in or on a cone, which cone can be
made to rotate round its own axis so as to take up or throw off more or less of the
wire and thereby increase or decrease the friction and consequently the tension of
the wire.
This improvement can be used in combination with the improvements described
in my 4th claim or it can be used in other cases when the gun does not move in the
direction of its axes, by giving the motion of translation to the paying-out cone and
dynamometer frame.
: