An Electric Pendulum for Firing Ships' Guns.
Year: 1890

page_text: Date of Application, 8th Aug., 1890-Accepted, 29th Nov., 1890
COMPLETE SPECIFICATION.
An Electric Pendulum for Firing Ships' Guns.
1, JOHANN JENC, of Verudastrasso, 2 Villa Jan, Pola, in the Austrian Empire,
Naval Artillerist, 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:―
My invention relates to improvements in devices or apparatus for firing ships' guns;
and has more particular reference to means for effecting the discharge of a ship's guns
at the proper moment for making a hit in spite of the presence, immediately in front
of the gunner, of the smoke from guns worked from another, or the same, level, but
more especially from machine guns up in the rigging.
The difficulty of taking a good aim in spite of the smoke is in itself great enough,
but it is frequently increased by either the ship rolling, or by her course being changed
at the moment of firing. Under such circumstances it is practically impossible to
mark the water line of the enemy's ship from even the bridge, or other equivalent
level, because the mast heads or, at the best, the funnels only will then be in the
gunner's line of sight.
In order that the invention, and the means of carrying it into practical effect, may
be thoroughly understood, I will now proceed to describe them in detail, referring in
so doing to the accompanying figures which are to be taken as part of this Specification
and read therewith.
Fig. 1. is a front elevation partly in section. The pendulum rods are broken away
in part.
Fig. 2 is a vertical section on the line a-b of Figs. 1 and 3.
Fig. 3 is, as to one half of it, a plan; and, as to the other half, a horizontal section
on the line CD of Fig. 2.
Fig. 4 is a half front elevation of the back plate.
Fig. 5 is a detail of the outer pendulum rod.
Fig. 6 is a vertical section of the upper end of the outer pendulum rod on the
line of Fig. 5, looking at it in the direction of the arrow e.
Fig. 7 is a vertical section of the same upper end on the line g―h of Fig. 5.
Fig. 8 is a vertical section on the line j-k of Fig. 3.
Fig. 9 is an inverted plan of the contact device.
Fig. 10 is a front elevation of the standard of the apparatus.
Fig. 11 is a part side view partly in section.
Fig. 12 is a half plan of Fig. 10.
Fig. 13 is a vertical section on the line m-m of Figs. 11 and 12.
Fig. 14 is a transverse section on the line n-o of Fig. 11.
Fig. 15 is a transverse section on the line p-q of Fig. 13.
Fig. 16 is a plan of the firing device.
Fig. 17 is a transverse section on the line -s of Fig. 16.
Fig. 18 is a front elevation.
Fig. 19, a side elevation; and
Fig. 20, a plan of the apparatus and standard, with a diopter attached.
Fig. 21 is a diagram illustrating the current distribution.
Referring to Figs. 1 to 9,
g is the bob of the inner pendulum; s, its red; and, z, a pivots. The rod s is continued
upward above its pivots, and carries at its extremity a contact-wheel p.
The pivots z, z, work in anti-friction bearings in the top of the tube A, which,
with the tube B, forms the rod of the outer pendulum. These two tubes are shewn
as connected by screwing the bottom of the portion of the tube B on to a threaded
collar upon the portion of the tube A.

page_text: The top of the tube B is expanded into a strong collar into which are screwed a
pair of pivots. The front one (by preference) is perforated for the purpose of
admitting the conductor into the interior of the tube B. Either or both collars
may he perforated.
The pivots, have provided for them roller bearings in or upon the top of a
bracket P which is jointed by pivots ; upon, or to, the back plate L.¸ u is an
adjusting screw upon the bottom of the back plate, by means of which the axis through
the pivots, may be always kept truly horizontal.
n is a
The hollow pendulum-bob 13 is shewn as made of two shells joined together by
screws, (the top shell being a continuation of the above mentioned portion ¹), and
terminates in an extension (. m, m is a frame supported upon the bottom of the
bracket P and is at such a height that the extension can beat within it.
clamping screw adapted to clamp the said extension in any desired position with
reference to the frame. The front face m¹ of the frame is graduated by half degrees
up to 3° on each side of the vertical centre or zero. e is a vernier carried by the
pendulum bob B¹.
The upper end of the rod B is closed by a cover which is shewn as held in position
by means of screws; and it is in this cover that the electric contact device is fitted so
as to rotate freely about its axis therein. This contact device consists of the following
parts. V is a cylinder pendant from the cover by the collar o. It is continued
upwards as a screw which carries the contact button K. c is an index projecting from
the button, and adapted thereby to move over a circular scale upon the cover d. This
scale runs up to 90° by divisions of 5°.
His a piston capable of a to-and-fro motion within the cylinder V. The piston
consists of an ivory centre inside a metal cap ¹, the latter being an expansion, or
continuation, of the piston rod.
(see Fig. 9) is a strip of platinum on the face of the piston opposite to the
index c, and is electrically connected with the cap ' and its rod. The latter moves in
an ivory tube 1, so that the piston is completely insulated. G is a spiral spring
adapted to impart elasticity to the motion of the piston, and to establish electric
communication between it, or the platinum strip, J, and the cylinder, V. An adjusting
screw i is also provided to limit the travel of the piston in either direction. The piston
is always in contact with the wheel upon the pendulum-rod 8.
.
T (Fig. 2) is an air port adapted to admit of the circulation of air.
The above described contact from K to J is capable of a common rotary motion
about an axis common to all the several parts composing it.
E is an S-shaped metal finger the tip of which bears upon the cylinder V. The
root of the finger is secured to, but insulated from, the inner face of the tube B. Jis
a conductor clamped to one of the holding screws of the finger E. It is led out
through the perforated trunnion to an insulated clamp L. Next to the latter is
placed a second clamp L which is in contact with the apparatus; and its object is-to
pass the return current through the apparatus if the return be not otherwise provided
for. This feature is explained more fully further on.
The axes of the pivots of both pendulums and the zeroes of the scales upon both
the frame m and the cover dare in the same vertical plane; and the said axes are also
at right angles with the back plate of the bracket P.
F, F are a pair of tension springs screwed on opposite sides, respectively, of the
upward continuation of the pendulum-rod 8. 19 are a pair of adjusting screws.
These engage the said springs F, F, respectively, for the purpose of limiting the
oscillation of the inner pendulum; and a second pair of springs on the inner surface
of the hollow bob of the outer pendulum, are provided for a similar purpose. Only
one of these is shewn, i. in Fig. 3.
Suitable levels are provided which, being adjusted to absolute accuracy or
shore, serve as true guides for the erection and maintenance of the apparatus in
position.
Referring to Figs. 10 to 20,
M is the hollow standard, made preferably of cast iron; and N, a tubular ‘caŝing

page_text: embracing, and firmly secured to, the upper part of it. The front of this casing is
enlarged so as to provide a backing of the same contour as, and to receive, the back
plate M (illustrated in Figs. 1 and 2 and described therewith), which is to be securely
bolted to the said backing.
NI (Figs. 18 and 19) is a horizontal plate fixed upon the top of the casing N, and
adapted to serve as the base of the diopter which is fixed to it by three adjustable
screws ¹, s, s. The diopter consists of a frame d' upon which are engraved lines
representing the pointings of the guns. is a pivot upon the frame d'. " is a bar
having the hinged front sight d and the hinged back sight d³. Across the orifice
of the latter a fine wire is stretched in the plane of sight. № is a clamping
screw.
T is the firing device fixed upon the casing N. It is made of ebonite or ivory.
is a push piece, and 2, its returning spring. ³, are a pair of spring contacts in
electrical contact with the clamping screws to, to, respectively.
It has already been pointed out that in the operation of my invention there is a
choice of route for the return current. Now if the vessel be used for it, then-
referring to Fig. 21-a conductor is taken from the positive pole of the battery B to
an insulated distributor bar, Y; and, from the latter, branches FFF, are led to
the respective guns G¹, (or to incandescent priming wires thereupon), from which the
current passes to the ship E'.
From the negative pole of the battery, the conductor is taken to one of the clamping
screws or of the firing device, and from the other of them to the insulated
clamping screw L (Fig. 8) on the apparatus. From there, the conductor J is taken
through the front hollow trunnion to either the insulated finger E or to the
cylinder V. The current will then flow through the spiral spring G to the platinum
strip J, and on through the contact roller p to the ship again.
But if, on the other hand, the ship is not used as the return conductor, then the guns
must be placed in circuit from which a conductor is taken to the non-insulated wire
clamping screw L'. The current will then flow on as above described.
My invention is applied and used as follows:-
The apparatus is mounted in the conning tower, on the bridge, or in any other
suitable position, but so that the plane of oscillation of its pendulum shall be at right
angles with the line of the keel, and the vertical axis of the outer pendulum, when
the latter is at 0°, stand truly perpendicular when the ship is in a normal
position.
Inasmuch as during the rolling of a vessel, the angular velocity increases with the
angle, and has its maximum as the ship passes its normal position, this co sideration
must receive due attention (apart from the interval of time which elapses from the
moment of firing to that of the emergence of the projectile from the muzzle), that is
to say, the firing must be effected before the line of sight passes the mark.
If the
roll is not more than, say, 5°, the time of rolling being about 6 or 7 seconds, as
generally happens, it will not count for much; but the case is different when the
pitch amcunts to 10, 15 or 20°, or if the period of oscillation is under 4 seconds.
Suppose the contact button K (Figs. 1 and 2) of the apparatus be set with its
index at 0°, the platinum strip J of the contact device is at right angles with the
plane of the pendulum's oscillation, and the contact wheel pis, during the pitching
inotion of the ship, in contact therewith for the shortest possible time.
Suppose the contact button be moved from its normal position through any angle to
the left or right, then the direction of the platinum strip forms a corresponding
angle with the plane of the pendulum's oscillation, and the contact wheel p slides
diagonally over the said strip as the ship pitches. Suppose the contact button is set
at 90°, then the plane of the pendulum's oscillation is coincident with the direction
of the platinum strip and the contact wheel rolls along it in any position of
the ship.
If the circuit is closed by the firing device, then the current passes through the
apparatus and conductors as long as the contact wheel is in contact with the
platinum strip.

page_text: When the vessel stands upon an even keel, the outer pendulum being then at 0°,
the said pendulum is suspended centrally in the apparatus, and its contact wheel
contacts with the middle of the platinum strip no matter what position the contact
button K may occupy. If, therefore, the push piece of the firing device T¹ be
then pressed, the closing of the current and the firing of the gun will be
effected.
The same will be effecied when the contact button is set at 90°, no matter whether
the ship stands on an even keel, or whether the outer pendulum be set at 0°
or not.
Besides, when the contact button is set at 0° and the outer pendulum at 50, to the
left, or port, for instance, and the push pressed down, the wheel p will only contact
with the platinum strip when the ship is heeled 5° over to the left, or rice versa. If
the outer pendulum had been set as many degrees to the right (starboard), then the
close of the current would be effected only when the ship had heeled 5° to
starboard.
Finally, as to the vertical prepointing. To repeat, inasmuch as during the rolling
of a vessel the angular velocity increases with the angle, and has its maximum as the
ship passes its normal position, and as also the amount of the vertical prepointing or
pre-levelling is proportional to the said angular velocity, it follows that the breadth of
the platinum strip J must be large enough, with reference to the different periods of
rolling, in order to bring the contact wheel sooner or later in contact with the said
strip, accordingly as the ship pitches more or less slowly.
Experiments have shewn that heelings of 10, 15 and 21.° correspond with the
motion of the contact button K of about 5, 10, and 20°. These data are for ships
with a rolling period of between 5 and 6 seconds.
In ships with other periods of rolling, the above numbers will vary somewhat, but
the degree of variation may, however, be easily and accurately calculated; and a
constant for the particular ship be so obtained.
For instance, suppose the enemy's ship is at a distance of 8-10 yards and your ship
pitches 15° each way, the mast heads only of the other being visible: In such a case
the guns are elevated accordingly and trained. The diopter is set according to the
training, the outer pendulum is set at 0° the contact screw upon 60°, and as soon as
the sight of the diopter bears between the masts, the firing device is operated and the
fire delivered.
When the ship pitches to one side only, and does not pass the normal position in the
other direction, then the outer pendulum is set free from its adjusting screw and
fixed, about in the middle of its throw, which indicates the minimum and maximum
rolling. The elevation of the guns to be fired must then be corrected by the angle of
rolling as ascertained. The other operations are as described above.
1 proceed in a similar case when the ship is over on one side only, or on an
even keel, for then the angle of inclination will be accurately indicated, and the
elevation of the gun can be corrected accordingly.
When the ship rolls uniformly from port to starboard, and when the distances
of the objects to be fired at change very quickly, it will be best when the required
angle of elevation does not exceed the maximum angle of rolling, to lay the gun
horizontally, and to leave the question of elevation to be decided by the scale.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. For the purpose of preventing the return beat of an inner peudulum suspended
on shipboard, enclosing the bob of the said pendulum in an outer one, or case,
surrounding it, and from centres fixed to the ship.
2. For the purpose of increasing the sensitiveness of the inner pendulum. referred
to in the previous claim, applying tension springs (FF) to its rod above the point
of suspension, and springs (Fi F¹) to the bob.
3. The combination of contact button K and strip J capable of a common rotary

page_text: motion about their common axis, whereby the commencement duration and termination
of the electric contact of said strip J may be regulated at will.
4. The tube A forming part of the hollow rod of the outer pendulum and sur-
rounding the rod of the inner one adapted to render electric contact possible only in
a definite inclined position of the said outer pendulum in consequence of the
suspension of the latter and the combination therewith of the double scale and
vernier.
Dated this oh ay ang
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.