Improvements in Apparatus for Range Finding, applicable to other like uses.
Year: 1892

page_text: Date of Application, 15th Oct., 1892
Complete Specification Left, 14th Aug., 1893-Accepted, 15th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Range Finding, applicable to other
like uses.
We, PHILIP JOHN RIBTON CRAMPTON, Captain Royal Artillery, c/o
Messrs. Cox & Co., of Charing Cross, and WILLIAM OLIVER SMITH, Electrical
Engineer, of 101 St. Martin's Lane, both in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
For range finding we provide two or more observing stations and at each a
telescope is mounted upon a vertical axis.
Or in the place of the telescope an apparatus for directing a beam of light may
be substituted.
The telescope or other instrument is brought to bear upon the object by means
of a worm and worm wheel or like gearing actuated by a crank handle.
The crank handle also gives motion to a circuit closer which transmits intermittent
currents through a line wire.
The currents transmitted by the circuit closer change in sign with the direction
of motion of the handle.
The line wires from the two or more observing stations converge upon a station
which we will term the chart station where is a chart. The positions of the observing
stations are marked upon the chart by optical appliances whereby light is directed
by a lens or mirror on to the chart and gives rise to the appearance thereon of a
radial line either luminous or in shadow.
Preferably the optical appliance is arranged as follows:-The source of light is
situate beneath the chart table; a tube passes upwards through the table and is
supported so that it can be rotated freely.
The light ascends through the tube and meets with a lens therein. Above the
lens is a wire and over this at the top of the tube there is a prism. This optical
appliance projects the shadow of the wire upon the chart as a radial line which
may be sharply focussed when required by the adjustment of the lens up or down
in the tube.
By means which we will presently describe an axis which carries the optical
appliance round with it is made to rotate in unison with the corresponding
observing telescope and the line projected on to the chart then travels over its
face.
The intersection of these lines marks upon the chart the position of the object
upon which the observing telescopes are directed.
If the purpose be range finding the distance or distances of the object from any
gun or guns in the neighbourhood can at once be obtained by measurement upon
the chart.
But the utility of the invention is not confined to range finding; the same
arrangements may be employed in marine surveying, for example without any
alteration in the appliances the course of a boat taking soundings in a bay might
be followed and the soundings as signalled at once marked upon the chart.
Or substituting a blank sheet for the chart similar means may be employed in
making and plotting a survey the telescopes then would be directed successively
upon a series posts or land marks in salient positions and marks representing
these would be made upon the blank sheet which would thus rapidly become a
more or less complete map.
We prefer to arrange the mechanism as follows:-
The avis carrving the ontical appliance is driven by a clock train controlled by

page_text: the currents passing in the line wire and provided with reversing gear which
operates with the change in sign of the currents. It is also provided with zeroising
apparatus so arranged that a signal current sent by the observer sets the axis to
one or other of a series of prearranged zero points.
This instrument we call the receiver. In the receiver there are two electro-
magnets in the coils of which the intermittent currents transmitted by the circuit
closer at the observing station pass. The first of these magnets as each current
passes attracts its armature and the armature moves the escapement of a clock train
actuated by a wound spring. On the spring barrel are teeth which, when the
escapement permits, rotate a toothed wheel upon an axis furnished with two other
gear wheels of different sizes. Parallel to the axis is another with wheels also of
different sizes but mounted loosely upon it. The larger gear wheels engage the
one with the other but between the smaller an intermediate wheel is interposed.
The axis with the loose wheels also carries a sliding clutch; the clutch is between
the wheels and can be so placed as to render either one or other of them fast with
its axis. This axis consequently always revolves whilst the clock train is in move-
ment but the direction of rotation depends upon the position of the clutch. A like
result may be obtained by other combinations of gear wheels. The clutch axis
also has a worm upon it and this engages with a wheel having worm teeth which is
fixed upon the indicator axis, that is to say the axis which required to keep pace
with the telescope at the distant station. The other of the above mentioned
electro-magnets has its cores both magnetised by one pole of a permanent magnet
its armature tongue being magnetised by the other pole with which it is connected
at one end whilst its other end is free to play between the extremities of the
magnet cores. According to the direction of the current in the coils the arinature
tongue will move to one core or the other and there remain and in its movement it
shifts the clutch above mentioned to one side or the other.
In order to ensure unison between the telescope and the indicator axis the
observer from time to time places his telescope to one or other of a large number
of prearranged marks (say the degree marks) and sends a current in a given
direction to the other end of the line. This current passes in the coils of a polarized
relay which switches on a local current through the coils of a pair of electro
magnets which by attracting their armatures hold the clutch already mentioned in
a central position.
The same movement causes a local circuit to be closed through another electro
magnet which by attracting its armature gives motion to a zeroising slide. The
axis of the propelling worm has a heart shaped cam upon it and the slide pressing
against the cam turns it to a zero position, the worm having previously been set
free from the clock work by the movement of the clutch as above stated.
When the observer at the telescope wishes to inform the central station that he
is following the course of a target and that the cross wires of the telescope are
"he sends a current in an opposite direction (than as above) through the coils
of the above polarised relay and thus gives any convenient signal.
"
on
In place of being driven by a spring the clock train may be propelled by electric
or other impulses.
In the observing telescope the transmitting and traversing handle is attached to
the frame carrying the telescope while the tangent wheel is fixed to the base
contrary to the usual arrangement. This allows of the telescope being traversed
without the hand being occasionally placed in awkward positions for doing so.
The pivot round which the whole works is hollow to allow of the passage of
electric wires.
Dated this 14th day of October 1892
•
PHILIP J. R. CRAMPTON.
WILLIAM O. SMITH.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Range Finding, applicable to other
like uses.
We, PHILIP JOHN RIBTON CRAMPTON, Captain Royal Artillery, c/o
Messrs. Cox & Co. of Charing Cross, and WILLIAM OLIVER SMITH, Electrical
Engineer, of 101 St. Martin's Lane, both in the County of Middlesex, 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:-
For range finding we provide two or more observing stations and at each a
telescope is mounted upon a vertical axis.
Or in the place of the telescope an apparatus for directing a beam of light may
be substituted.
The telescope or other instrument is brought to bear upon the object by
means of a worm and worm wheel or like gearing actuated by a crank handle.
The crank handle also gives motion to a circuit closer which transmits intermittent
currents through one or more line wires.
The currents transmitted by the circuit closer either change in sign or are
switched on to a different wire according to the direction of motion of the
handle.
The line wires from the two or more observing stations converge upon a station
which we will term the chart station where is a chart. The positions of the
observing stations are marked upon the chart by optical appliances whereby light
is directed by a lens or mirror on to the chart and gives rise to the appearance
thereon of a radial line either luminous or in shadow.
By means which we will presently describe an axis which carries the optical
appliance round with it is made to rotate in unison with the corresponding
observing telescope and the line projected on to the chart then travels over
its face.
The intersection of these lines marks upon the chart the position of the object
upon which the observing telescopes are directed.
If the purpose be range finding the distance or distances of the object from any
gun or guns in the neighbourhood can at once be obtained by measurement upon
the chart.
But the utility of the invention is not confined to range finding; the same
arrangements may be employed in marine surveying, for example without any
alteration in the appliances the course of a boat taking soundings in a bay might
be followed and the soundings as signalled at once marked upon the chart.
Or substituting a blank sheet for the chart similar means may be employed in
making and plotting a survey the telescopes then would be directed successively
upon a series posts or land marks in salient positions and marks representing these
would be made upon the blank sheet which would thus rapidly become a more or
less complete map.
In order that our invention may be fully understood and readily carried into
effect we will proceed to describe the drawings annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of the observing instrument which is also the
transmitter it being connected with the chart station by an electric cable.
Figure 2 is a plan of the base of the observing instrument.
Figure 3 is a plan of the upper part of the same instrument, the observing

page_text: Figures 4, 5, 6, 7 and 8 show separately parts of the mechanism.
The remaining figures relate to modifications and subsidiary arrangements.
1 is a base plate, it has a hole in the centre in which a screw thread is cut and
it is screwed on to a suitable support at the observing station, either permanent or
portable according to circumstances. 22 are screw legs on which a piece 3 stands.
44 are clamping screws for locking the piece 3 fast with the base when its position
has been adjusted. 5 is a worn wheel, it is fixed upon the hollow conical stem or
axis 6 which fits into a corresponding hole or socket in the middle of the piece 3.
The axis 6 has a retaining nut on its lower end; it also passes through a clamping
collar 7 in which for the purpose of adjustment it is free to turn but when the
adjustment is nearly complete the collar is clamped fast upon the axis by tightening
the binding screw 8. The clamp itself is connected with the piece 3 by a screw
When the instrument
and nut 9 by means of which the final adjustment is made.
is ready for use the worm wheel 5 is fast with the base plate 1 and its support.
10 is a turn table on which are the V standards 11 carrying the trunnions of the
telescope 12 as in a transit instrument.
The turn table 10 has a hollow axis 13 which fits within the axis 6 and is able
to turn freely; it has a retaining nut at its lower end. The turn table 10 carries
a horizontal axis 14 on which is a worm 15 engaged with the worm wheel 5.
16 is a toothed wheel on the axis 14, it is in gear with a pinion 17 on an axis 18
also carried by the turn table and provided with a handle 19. By turning the
handle 19 the telescope may be made to slowly follow the movement of an object
in the field of view. There are graduations upon the edge of the part 5 and a
vernier upon the part 10 by which the position of the telescope in azimuth may be
ascertained and adjusted. It is convenient that the speed of the gearing should be
such that one hundred and eighty revolutions of the worm 15 go to one complete
rotation of the turn table. On the axis 18 there is also a cam 20 which as the
cam revolves acts upon a roller carried by an armi 21. The arm is upon an axis 22
and a blade spring 23 resting against the flat base of the arm tends to retain the
arm in the central position in which it is represented in Figure 6 and to return it
to this position after it has been displaced by the cam. Thus the cam imparts a
rocking motion to the axis 22 and the motion takes place on one side or the other
of the central position according to the direction in which the handle 19 is turned.
The axis 22 also has on it a commutator consisting of a disc 24 of insulating
material with two metal sectors 25 and 26 fixed upon it. These sectors are
connected respectively with the positive and negative poles of a battery. The
connecting wires are led up through the hollow stem or axis 13 and are clamped by
screw terminals 27, 27. A three wire cable laid between the transmitting station
and the chart station is connected with the instrument by similar means.
Two contact springs 28 one of which is shown in Figure 5 connect the battery
terminals with the sectors 25 and 26. There are also two other springs 29 one on
either side (one is shown in Figure 5) which are in electrical connection with two
of the cable conductors; the ends of these springs when the instrument is at rest
are insulated and no current passes by the springs into the cable. But when by
the action of the cam 20 the arm 21 is caused to rock the springs 29 make
intermittent contacts with the sectors 25, 26 and a succession of electric impulses
or short currents pass through the cable; the direction of these currents being
dependent on the direction of rotation of the handle 19 and axis 18.
The turn table 10 is also provided with another axis 30 on which is a handle 31.
The handle is held in the position in which it is shown by a spring 32. By the
action of the spring the arm 33 upon the axis is pressed against the stop 34.
The spring however will allow the axis to be turned until the arm 33 comes up
to the stop 35 but immediately the axis is released it will return to its original
position. The axis has upon it another commutator disc similar to that already
described. This commutator is connected with the transınitting battery and with
two of the cable wires namely the wire unused at the other commutator and a
return wire which is common to both commutators. The current is normally

page_text: closed through the commutator controlled by the handle 31, the movement of the
handle reverses the direction of the current.
There is however a press button like that of an ordinary electric bell, but
which is not shown in the drawing. This press button is near to the eye piece of
the telescope so that it can conveniently be pressed whilst observing; when it is
not so pressed it opens the circuit of the second commutator.
It will thus be seen that the rotation of the handle 19 moves the telescope 12
around a vertical axis and also transmits through one of the cable circuits
intermittent currents of a sign dependent on the direction of rotation of the
handle.
Pressure upon the contact button mounted on the telescope transmits a current
through the second cable circuit and the sign of this current depends on the
position of the handle 31.
These currents are utilised in the receiving instrument at the chart station and
this instrument 1 will now proceed to describe.
Figure 9 is a plan partly in section of the instrument at the chart station.
Figures 10 and 11 are transverse vertical sections of portions of the same.
Figures 13 and 14 are opposite side views of the instrument. Figures 15 and
16 are vertical sections of the light projecting appliance. These sections are taken
in planes at right angles the one to the other.
32, 32 are wheels of a clock train, which as is usual is actuated by a wound
spring and is controlled by an anchor escapement 33. The axis 34 has mounted
loosely on it two pinions and fixed to these pinions are the clutch discs 35, 35.
The pinions are so geared with the clock train that they rotate at the same speed
but in opposite directions. The anchor escapement 33 is upon an axis 36 which
has an arm 37 connected by a link with the armature 38 of an electro-magnet 39.
The electric impulses produced by the rotation of the handle 19 in the trans-
mitting instrument and which pass through one of the cable circuits traverse the
coils of the electro magnet 39. So the anchor escapement receives the oscillatory
movement necessary to permit the clock train to run. 40 is a long lever having a
fulcrum at 41; at its other end it is forked and embraces the neck of the toothed
clutch 42. This clutch can slide on the axis 34 but when the clutch revolves it
carries the axis round with it. The lever 40 also is or carries a permanent magnet
with a pole situate between the pole pieces 43, 43, of the electro magnet 44. The
same electric impulses which control the escapement anchor 33 also pass in the
coils of the magnet 44 with the result that one or other pole piece 43 attracts the
lever 40 according to the direction of the electric impulse passing in the circuit or
in other words according to the direction in which the handle 19 of the transmitter
is turned. The lever 40 according to the side to which it is attracted causes the
clutch 42 to engage one or other of the clutch discs 35 and the axis 34 is rotated
by the clock train. The axis 34 has upon it a worm 45 which is engaged with a
worm wheel 46. So it is arranged that the worm wheel 46 shall rotate in unison
with the turn table 10 of the transmitting instrument.
"
The axis 47 of the worm wheel 46 is pivotted at its lower end, and its upper end
projects through the upper plate of the frame and is tapered and squared so that
the light projector may fit accurately upon it. 48 is a coiled spring connected at
one end to the axis and at the other end to the frame to give to the axis 47 a
tendency in one direction to prevent "backlash when the direction of rotation is
changed. The light projector consists of a tubular metal frame 49 closed at its
lower end and open at the top. Above the open top of the frame is an incandescent
electric lamp not shown in the drawings; it shines downwards into the open end of
the tubular frame and from other directions the light is shaded.
Within the frame is a slide 50 carrying a convex lens and beneath the lens a fine
wire strained horizontally. The lens is of such power that the light after passing
through it is parallel or nearly so. Beneath the lens and the wire is a glass prism 51 ;
the light enters this prism, is totally reflected by the inclined side and emerges at

page_text: the front by a window or aperture 52 formed in the frame. The face of the prism
is convex and of such curvature that the light is brought to a focus and an image
of the wire is projected on to the surface of the chart table which extends for
several feet in front of the light projector. The image of the wire can be rendered
sharp for any distance from the projector by the adjustment of the slide 50 a short
distance up or down in the frame 49. The prism 51 is mounted on trunnions so
that it can be tipped slightly about a horizontal axis; thus the beam of light issuing
from the window of the projector may be made to strike the table surface in the
manner most convenient.
The further mechanism which I will now describe is intended from time to time
to disconnect the axis 34 from the driving train and bring it to a starting point or
zero position so as to start the telescope and projector in exact accord and also to
test from time to time so that if the escapement should have failed any loss or gain
may be corrected.
These objects are accomplished by currents passing in the second cable circuit,
which currents it will be remembered are determined by the use of the press button
mounted on the telescope of the transmitter and depend as to their direction on the
position of the handle 31. These currents come to a polarised relay at the chart
station which closes one or other of two local battery circuits. One of these is the
circuit of the incandescent lamp so that the lamp burns at such times as the
observer making use of the telescope desires and when the light shines the attendant
at the chart station will infer that the telescope is laid on the object to be observed.
The other of the two local circuits is used for "zeroising" that is to say for insuring
that the transmitter and the receiver are in unison and correcting any error which
may have arisen. When the observer at the telescope station considers the adjust-
ment to zero to be necessary he brings the worm 15 which turns his telescope
exactly to a zero position (say by setting the vernier to read 0 degrees or 4 degrees
or 8 degrees or other multiple of 4) he then holds over the handle 31 and pushes in
the press button. A current is thus sent through the cable which influences the
polarised relay and the circuit of a local battery is closed through the coils of the
magnet 53. The magnet 53 has two armatures 54, 54 hinged to a support and
provided with jaws 55, 55.
When the armatures are attracted springs 56, 56 in connection with them are
overcome they rise and their jaws close on the lever 40 bringing it to a central position
and there holding it. The clutch 42 is then disengaged. The armatures 54, 54 in
rising close another local battery circuit by coming against the contact springs 57,57
and the current flows in the coils of the magnet 58. The armature 59 of the magnet
being attracted, it, by means of levers and links as shown, gives motion to a slide 60.
The axis 34 has upon it an ordinary heart shaped cam 61 which is not clearly seen
in the drawing and when the slide 60 advances its nose 62 comes against the cam.
The cam is then compelled to yield by the turning of the axis 34 until at the zero
point the smallest radius of the cam comes round to the nose 62 which then is just
able to pass beneath the axis. This use of a heart cam is a well known means of
bringing an axis to a zero point. As soon as the current ceases to flow in the cable
circuit and in the local circuit a spring causes the return of the slide 60 and the
axis 34 is set free and the instruments are again ready for work.
There are two or more light projectors at the chart station cach working in
connection with a corresponding observing and transmitting station. These light
projectors are positioned in relation to the lines of the chart as the observing stations
are positioned in relation to the actual landscape.
For example if the chart be upon a scale of 50 inches to the mile and a mile be
the distance between two observing stations, then there will be a distance of
50 inches between the corresponding light projectors, measuring from centre to
centre. Likewise any object which is a mile distant from an observing station will
be indicated on the chart at a distance of 50 inches from the corresponding light
projector.

page_text: The mechanism which we employ in carrying out our invention may be much
varied; thus simple sights may be substituted for the telescope or for use at night
the telescope may be replaced by a search light.
The electrical appliances admit also of modification, for example, another form
of instrument suitable for use at the chart station is shewn by the Figures 17
to 23.
Figure 17 is a plan. Figure 18 is a longitudinal section on the line a a in
Figure 17 omitting some of the parts. Figure 19 is a transverse section on the
line in Figure 17. Figures 20, 21 and 22 are horizontal sections of the light
projector and Figure 23 is a plan of a portion thereof. In this case the light
projector is illumined by an electric lamp beneath the table. The light passes
upwards through convex lens at 63 where also immediately above the lens is a wire
strained diametrically across it. 64 is a prism which reflects the light and focusses
an image of the wire upon the surface of the table up through which the light
projector protrudes. The lens, wire and prism are all contained in a frame 65
which is suspended by a pivot 66 at its upper end from the top of a stationary outer
frame 67. The rotating frame 65 is held also near its lower end between guide
rollers 68. The lens and wire are on a carrier 69 seen separately in plan at
Figure 23; it can move up and down within the frame 65 on three guide wires
which pass through the arms of the carrier. The carrier has upon its arms
rollers 70 as is seen in Figure 23. The rollers 70 rest upon a guide ring 71 which
can be raised and lowered in the stationary frame 67. Upon the pivotted frame 65
there is fixed the spur wheel 72 and this gears with another spur wheel 73. To
prevent "backlash "this wheel is made in two parts, an upper and a lower one part
only is fixed to the axis 74 and a spring connected with each is lodged in a cavity
between the two parts. Thus no free space is left between the teeth of this
compound wheel 73 and the teeth of the wheel 72 which it drives.
The wheel 73 carries the axis of the bevelled wheel 75 which engages with two
other bevelled wheels 76, 77, loose on the axis 74. The bevelled wheels 76 and 77
are likewise compounded in the manner already described with a view to avoid
backlash. There are in this instrument two clock trains one arranged to drive the
bevelled wheel 76 by means of spur teeth upon it and the other to drive in like
manner the bevelled wheel 77, 78 and 79 are the spring barrels and 80, 81, are the
fuzees of these two clock trains. The fuzee 80 it will be seen has upon its axis,
connected in the usual way, a spur wheel engaged with the spur teeth of the
wheel 76. The wheel 76 drives a pinion 82 and the bevelled wheel 83 on the same
axis drives the pinion 84 on the axis of the escapement wheel 85, 86 is the
escapement anchor, on the same axis is an arm 87 connected by a link with the
armature 88 of an electro magnet 89. The two clock trains it will be seen are
entirely distinct and are controlled by separate electro magnets 89, 89. These
magnets are either on separate cable circuits or there may be a polarised relay to
receive the currents arriving through the cable and to translate them according to
their sign into currents in one or other of two local battery circuits in which the
two magnets 89, 89 are respectively included. 90 is the zeroising magnet, it may
be so arranged that it receives current as already described from the transmitter
and it then attracts its armature 91 and rocks the axis 92. This causes two claws
to be brought into the path of pins projecting from the sides of the escapement
wheels 85, 85. When the pins come against the claws the escapement wheels are
stopped each at its zero position.
When the escapement magnets 89, 89 are placed in separate cable circuits we
employ in the transmitting instrument at the observers station a commutator such
as is shown by Figure 24. In this instrument the axis 18 (which is turned by a
crank handle as already described in respect to Figures 3, 4, 5 and 6) has upon it
cam like projections 20 which, as before, act upon a roller 21 to impart a vibrating
motion to an axis 22. The axis 22 has upon it an arm 93 and this arm makes and
breaks contact with one or other of the spring fingers 94 according as the rotation
of the axis 18 is in one direction or the other. The fingers 94 are mounted with

page_text: suitable insulation and are connected with the terminals 95 and 96 where two of the
line wires of the connecting cable are clamped. These line wires as well as another
line wire mentioned further on are connected in parallel with one of the poles of a
battery at the chart station: the other part of the battery is connected with the
metallic sheathing of the cable which answers the purpose of an earth.
The contacts on the arm 93 are in electrical connection with the sheathing of the
cable the metal of the framework of the observing instrument forming the conductor
and a wire from the sheathing being connected up with terminal 101 which is
attached to the said framework.
The other line wire of the connecting cable is clamped to the terminal 98. The
terminals 98 and 100 are connected electrically through a resistance coil 99. The
terminal 100 is connected electrically to the key on the telescope 12 which as
already stated is to be pressed by the observer when the telescope is laid on
the mark.
When this key is pressed into contact with the metal casing of the telescope a
current goes to line through the resistance coil 99 it proceeds from the battery r at
the chart station to the observing station through the resistance coil 99 then and
thence through the metal of the observing instrument into the sheathing which is
equivalent to an earth. At the chart station this current passes through an
ordinary relay (not shewn in sketch) and also through the electro magnet 90. In
consequence of the resistance coil 99 introduced into the circuit the current is not
strong enough to cause the electro magnet 90 to attract its armature but it is strong
enough to cause the relay to close the local circuit of the electric lamp which
illuminates the light projector.
When it is desired to zeroise, the resistance coil 99 is cut out of the circuit by con-
necting the terminals 98 and 101 and thus the resistance in circuit is sufficiently reduced
to permit a sufficiently powerful current to pass. Each of the binding screws 98, 101
is electrically connected with a contact spring and these bear against a barrel 102
which is partly metallic and partly of insulating material. This barrel is on an
axis 30 which can be turned partly round by means of a handle 31 as already
explained.
In making use of this zeroising apparatus the operator at the transmitting station
puts over the handle 31. He then turns the handle 19 so as to carry his telescope
two degrees beyond the nearest zero point of his scale and then comes back
accurately to this point. Then on releasing the handle the instruments are ready
to recommence work.
Figure 26 illustrates the circuit arrangements suitable for a fortress. One
observing station is shown and one chart station with the adjacent gun battery
which it directs. Also a central station is shown which receives a cable from each
observing station and from each chart station.
The attendants at the central station control the connections between cable and
cable so that the information supplied by any observer may be forwarded to any
chart station or stations which have need of it.
At the
In addition to the wires already referred to every cable contains a pair of
wires reserved for telephonic communication. In the figure the observer at the
observing station is shown with receiving telephones a secured by bands to his
head and a transmitting telephone T attached to the telescope and at a suitable
distance from his mouth. The telephones may be of any ordinary sort.
lower part of the figure the extremities of six cables are seen; they are led in
from as many observing stations but any number of observing stations may be
provided. In each case the three cable wires which control the mechanism are
brought to insulated terminals at c and the telephone wires to similar terminals
at d d. On each telephone line a drop shutter may be provided as indicated by the
numbered discs so that the observers may have the means of calling the attention
of the central station when necessary.
In Figure 26 e e show two cables led in from two different chart stations and
in like manner every chart station would be provided for. These cables contain

page_text: a considerable number of insulated wires, in the drawing three sets with three
wires in each set are shown. They are led to insulated terminals ff and by
plugs connected by flexible conductors such as g inserted at c and through
communication between the observing station and the chart station can be
established. When at work at least two observing stations are thus connected
with each chart station. The cable from each chart station also contains two
other pairs of wires; one pair for telephonic use is brought to terminals h h and
by plugs and cord conductors these can be coupled with the terminals d to establish
ordinary telephonic communication between the observing station and the chart
station. The object of the pair of wires i connecting the chart station with the
central station is to convey automatic clock signals and other information as herein-
after described.
k is a clock which every half minute closes a local circuit in which a battery is
included. The current passes through the primary coil of each of the induction
bobbins one for each chart station. A second winding on the bobbin 7 is in the
circuit ; an induced current the result of the action of the clock consequently
passes in this circuit; it rings a bell at the chart station. The circuit i in each
case has also a coil on the corresponding induction bobbin m and on the same
bobbin there is a secondary coil which by plug connections can be made part of
the telephone circuit leading to either of the observing stations, and the current
can by the arrangements indicated be put through several of the observers tele-
phones in series. In this way each observer whilst he is at work is supplied with
time signals; it is his duty at each half minute to align his telescope correctly;
this is easier for him than it would be to maintain the correct alignment continuously.
The secondary coils of the bobbins m m can be connected in series by plugs and a
flexible conductor n. The central station by means of a portable or other telephone
can carry on conversation with any observing station and any battery.
o o indicate
plug connections by which the chart stations may be coupled in parallel so that
two or more chart stations may be influenced by operative currents controlled by
one and the same observing station.
At the chart station p is the plotting board with the chart upon it and standing
properly placed with respect to this chart are three light projectors qqq although
two only need be employed. Each light projector is connected through the
cable with its corresponding observing station. The main battery is shown at r;
one of its poles is connected with the sheathing of the cable; the other is
connected through the light relay and the magnet 90 with one of the line wires.
The two other line wires are connected respectively with the windings of the
magnets 89; at their other ends these windings are connected with the terminals 95
and 96. Thus when the distant end of one of the battery connected line wires is
coupled with the sheathing of the cable a current flows through the corresponding
magnet coils 89.
Also when the distant end of the third battery line wire is
connected with the sheathing of the cable a current of greater or less strength
passes through the magnet 90 and the light relay. By means of these currents as
already fully explained intersecting rays of light are projected across the chart
and when firing at a moving target it is the duty of an attendant at every half
minute to strike pins into the plotting board at the points of intersection. These
pins show successive positions of the object or target. The officer in command of
the battery being in the chart station from the information thus derived directs
the elevation and training of his guns. The chart station is arranged as close to the
guns as circumstances admit and orders are transmitted by word of mouth or by
speaking pipes.
The guns themselves may be completely masked so that the object cannot be
seen from the firing point.
s is the bell at the chart station which sounds the half minute, it is in the
circuit i and so is also one of the coils of the induction bobbin t. u is the telephone
by which the chart station speaks with any other station with which the central
station may couple it. When at work however the observers telephones are

page_text: otherwise occupied and the induction bobbin t affords the means of sending Morse
signals without interfering with the time signals. is the signalling key, when
depressed it completes the circuit of one cell of the main battery through the
primary winding of the induction bobbin t; the result is that each observer hears
a buzz in his telephone and such buzzes being arranged according to the Morse
code information is conveyed. wis a firing key which is depressed by the officer
in the chart station when the gun or guns are to be fired. x indicates the gun
and y a switch in the immediate neighbourhood of the gun which only allows it to
be fired when set for the purpose. The firing circuit may be traced from the
battery through the key w, through the electric tube in the breech of the gun,
through the contacts of the switch y and so back to the battery.
When the switch y is put over so that the handle rests against the stop pin on
the left side the contact springs of the switch rest on insulating segments upon
the handle or moveable part of the switch and no current can pass even if the
firing key be pressed.
Another circuit may also be traced when the switch y is in the position shewn
in the figure; it includes one cell of the battery and the current passes thence
through the spring contacts of the switch y and the primary coil of the induction
bobbin t. In this circuit there is also a vibrator not shewn in the drawings but
such as is common in electric bells. The vibrator continually opens and closes
the circuit so long as the connection through the switch y continues. The vibrator
emits a sound which announces in the chart station that the gun is ready to be
fired and this sound is repeated by the telephones of both or all the observers
connected on to the circuit wires and lets these observers also know that their
gun is ready to be fired and that especial care on their part is necessary in
following the moving target in order that the gun may be fired precisely when it
arrives at the position upon which the gun has been laid.
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. The apparatus substantially as described consisting of two or more observing
telescopes or equivalent instruments at observing stations and electrically connected
with indicators at a chart or receiving station, the whole so arranged that the
telescopes and indicators move in unison and the indicators will at any time point
out on a chart or receiving surface a position corresponding to that occupied
by an object upon which the two telescopes are simultaneously directed as herein
set forth.
2. Observing apparatus substantially as described consisting of a telescope or its
equivalent so arranged that by the rotation of a handle it can be moved in
azimuth whilst also by the rotation of the handle electric impulses differing
according to the direction of rotation are transmitted through the cable; also
receiving apparatus substantially as described in which an indicator controlled by
the electric currents received from the observing apparatus rotates in unison
therewith, the two moving through equal arcs in similar directions as herein
set forth.
3. Receiving apparatus substantially as described furnished with light projectors
rotated electrically in unison with an observing telescope or its equivalent and
serving to throw an indicating ray over a chart or other receiving surface
announcing the direction in which the observing telescope is directed.
4. The several instruments herein described and represented by the Figures 1
to 25 of the drawings.
PHILIP J. R. CRAMPTON.
WILLIAM O. SMITH.