Improvements in Electric Search Light Apparatus.
Year: 1893

page_text: Date of Application, 5th June, 1893
Complete Specification Left, 5th Mar., 1894-Accepted, 5th May, 1894
Improvements in Electric Search Light Apparatus.
I, GASTON SCIAMA Manager of the Firm of Bréguet, of 19, Rue Didot, Paris,
France, Electrical Engineer, do hereby declare the nature of this invention to be
as follows:-
-
This invention relates to improvements in electric search light apparatus capable
of being manipulated electrically from a distance or directly by hand.
The apparatus comprises the optical part or projector; the operative mechanism;
the mechanism for distributing the electric current; and the lamp; and it is
illustrated in the accompanying drawings, forming part of this Specification,
wherein
Figures 1 and 2 are vertical sectional elevations of the optical part or projector
and its operative mechanism; Figure 3 is a diagram, and Figures 4 and 4 are
sectional elevations and Figures 5 and 54 a plan and horizontal section on line c, c
Figure 4, of the manipulator; whilst Figures 6 and 7 are sectional elevations, and
Figure 8 a diagram, of the lamp mechanism.
The optical part comprises a parabolic crystal mirror differing essentially from
the spherical mirror or from the aplanatic mirror with spherical surfaces of unequal
radii heretofore used. The spherical mirror might be substituted for the
parabolic mirror, if constituted by a thin segment of a sphere of large
radius, but in this case the focal length being equal to the radius is very
great and as the luminous intensity of an object lighted diminishes as the
square of the distance of the source of light from the reflector, it is highly
important to bring the focus as near as possible to the mirror. The aplanatic
mirror enables the focal distance to be diminished but involves a mirror of great
thickness especially at the edges and consequently of great weight and a loss of light
due to the double refraction which the luminous ray must undergo in order to be
brought parallel to the axis of the mirror. Moreover the focal length of an aplanatic
mirror is always greater than that of a parabolic mirror of the same aperture. The
parabolic mirror is, therefore, far superior to the others as regards thickness,
weight, and power of illumination. Having found that, especially with horizontal
carbons, the central zone of the mirror is practically useless, a central aperture is
made in the mirror with a view to render more efficacious the ventilation of the
silvered surface and enable the luminous intensity to be very much augmented, to
facilitate the manufacture of the mirror, and enable the reflector the better to resist
the air pressures due to the discharge of cannon. The parabolic mirror whether
apertured or not, throws a luminous beam which is truly parallel to the optical axis
when the source of light is placed at its focus. In certain circumstances it may be
desirable to spread the beam in a given plane and this result is obtained by the
interposition in the path of the beam of a series of diverging plano-convex lenses
fixed in a frame arranged in the manner hereafter described whereby to spread the
beam in any direction desired.
In Figures 1 and 2 of the drawings, the mirror i fitted in a carrier d and covered
with a cap is attached to the hood a of the projector by cars e so as to be easily
dismounted. The hood is closed at front by a plane glass j carried by a hinged
bezel. Four supports formed on the flange k of the hood serve to receive the
diverging lens carrier whose octagonal form adapts it to be attached in any
direction. To the underside of the hood is attached the box containing the lamp
mechanism, the arrangement being such as to admit of the lamp being adjusted in
the direction parallel to the optical axis without interrupting the current, this

page_text: adjustment being effected by a screw turned by a hand wheel v. A polished prism me
whose surface on the side of the incident rays is convex and on that of the emergent
rays concave, throws the image of the arc on a ground glass screen and enables the
variations of the arc to be followed without opening the hood. A shutter operated
from the outside by a handle ¹ is provided for the emission of optical signals.
The hood a is supported by trunnions 6 in standards e rising from a plate o running
on four rollers and guided by a central hub that enters a socket in the top p of the
pedestal g. Au arrangement consisting essentially of a right-angled prism mounted
on one of the trunnions b permits of throwing upon a voltmeter a small beam of
light in whatever position the hood a may be and notwithstanding that the voltmeter
is fixed, the trunnion being for this purpose bored axially so that the ray of light
passing through it may fall on the prism and be thence transmitted to the
voltmeter.
The operative mechanism has for its object to enable the beam of light to be
projected in every direction for sweeping the horizon and it is designed to enable
these movements to be produced either directly by hand or from a distance and
either rapidly or gradually. The movement in altitude or of inclination, may be
effected directly by worm gear applied to one of the trunnions of the hood and
rendered fast or loose by a clutch so as to enable a slow or a sudden movement of
inclination as required. The projector is operated from a distance by means of an
electric motor through the medium of a spindler passing through the hub of
plate o and engaging by collars at its upper end with a stud on a lever wy one of
whose arms is graduated to enable an initial upward or downward inclination of a
certain number of degrees to be given to the projector. The arm y is connected to
the hood a by a rod z and when 0 and y are rigidly connected by tightening a
key the vertical motion of spindle causes a corresponding motion of the
projector or by loosening the key a the projector may be moved freely in any
direction by hand. The spindler is screw-threaded and traverses a nut in a skew-
wheels in gear with another skew-wheel on a spindle u provided with a hand wheel.
If an electric motor a actuating the spindle u be arranged within the base, move-
ments in altitude may be effected from a distance it being only necessary to provide
a device whereby to break the circuit when the spindler has attained either of its
extreme positions and avoid the burning of the motor which would occur were the
current in the same direction to be continued indefinitely. For this purpose two
lugs are provided at the lower end of rod that engage with the bell-crank lever g¹
which a spring tends to hold in one of its extreme positions. The axis of this
lever carries a switch which according to the position of the lever bears on one or
other of the contact levers d¹ and breaks the circuit of the electro-motor a¹ every
time that the projector reaches one of its extreme positions at the same time that
the current for working in the opposite direction is established, the two contact
levers being connected by an insulated spring.
The mechanism for imparting the movement in azimuth comprises a worm wheel i¹
capable of being made fast or loose on the hub of the movable plate o. When loose,
the plate o and consequently the whole projector can be turned freely; when fast,
the plate can be turned gradually by the operation of a worm shaft u gearing with
wheel, the operation from a distance being effected by an electro-motor m" geared
by an endless chain with the shaft u¹.
The distribution of the current in the projector is effected as follows:-The main
leads or cables for the conveyance of the current are attached to the terminals n
and in connection the one directly, and the other through the medium of a switch,
with two brass rings fixed on a wooden base o¹ screwed to the pedestal top p.
The current passes, through the medium of the brushes r¹ in contact with rings p',
to the two biuding screws s¹ fixed on the plate o and connected, by flexible cables,
either to the terminals of the lamp-box or of the lamp itself.
When the projector is to be controlled from a distance a manipulator is provided
whereby the current for the motors a¹ and m¹¹ is controlled, the connections between
the source of the current, the manipulator, and the two motors being indicated

page_text: 66
diagrammatically in Figure 3 whilst Figures 4 and 4^ show sections & Figures 5 & 5^
plan and horizontal section of the manipulator. The manipulator comprises twelve
keys, a circuit-closer or switch, and resistances suitably connected to the keys, its
principle of action being as follows:-When a current is about to be sent through
the motors by the closing of the circuit at the manipulator, the current passes
directly through the field maguets whilst it only passes through the armatures
through the medium of resistances which are sufficient to prevent the setting of the
motors in motion. When, however, one or more of these resistances are short
circuited, the motors rotate more or less rapidly. For this purpose there is
provided a plug switch S, two terminals B B for connection with the source of the
current, knobs labelled "Upwards," "Downwards,"
," "Left quickly," "Left slowly,"
Right quickly," "Right slowly," or distinguished by equivalent expressions and
which it is only necessary to depress in order to impart corresponding motions to
the luminous beam. The sectional and plan views shew the twelve keys a', a³, a³,
to a¹, of which one extremity is mounted to oscillate freely on the rod t. At the
other extremity of the keys is fixed a contact-screw and an attachment for a spiral
spring c connected at its other end to a fixed point which serves also for the con-
nection of the wires, as shewn in the cross-section. Below the contact-screws of the
keys are arranged flat contact springs 1, 2, 3, 5, 7, 77, 78, 70, 11, 12, the screws
by which these springs are fixed serving also as binding screws for the conducting
wires. It will be seen that the keys at and a have no contact spring beneath
them but a contact-screw fixed in the top of the box, the object of these two keys
being to short-circuit the corresponding armature. At starting, it is necessary to
commence by breaking the short circuit of an armature and short-circuiting a part
of the resistance. With this object the keys a¹ a² a a7 a³ and a¹, are provided
with arms which bear at the same time on the keys a³, a, a, and a³, a¹º, a
Referring to the diagram, Figure 3, it will be seen that by pressing, for example,
the knob No. 1 ("Left quickly" in Figure 5) before the contact is established at
the spring r¹, the arm of key a¹ will carry with it the key a and break the short
circuit The current is then free to pass through the armature of the motor for
producing the movement in azimuth by following the path b, c, d, e, f, g, h, i, k, l, m,
but the movement will not yet take place by reason of the resistances d, e, and l, k;
but immediately on the breaking of the short circuit 4, the key a³ which also
partakes in the movement of a¹ comes in contact with the spring and thereby
short circuits the resistance l, k, and the armature is thereupon put in motion.
In short, as soon as the key a¹ bears on the spring (and these three motions
although successive are nearly instantaneous) the resistance de will also be short
circuited and the motor will run at its highest speed. By pressing on the knob
No. 2 it will be easily seen that the same action will occur except that instead
of ultimately short-circuiting the resistance de, the portion s e only will be short-
circuited and the action will be slower. By pressing on the knobs 3 and 4 the
operation is similar, except that a current is sent in the opposite direction
through the motor. By means of the knobs 5 and 6 the motor by which the
movements in azimuth are effected, is set in motion in the one or other direction.
It will be evident that both the electro-motors may be set in action simultaneously
by pressing the knob 5 or 6 and at same time on one of the four others.
The lamp whether operated electrically from a distance or directly by hand is an
electric regulator with continuous current and horizontal carbons although the
system is equally applicable to a regulator with vertical or inclined carbons.
The lamp is illustrated in Figures 6, 7, and 8, and comprises the positive and
negative carbon holder, an electric motor, a spring barrel, and a relay.
The
positive carbon holder is a standard a provided at top with a jointed clip b. It is
adjusted for height by a cam on a spindle c turned by a hand wheel so as to regulate
its position with regard to the negative carbon. The carbon holder is mounted on
a carrier d running on four rollers e and this carrier is provided with a rack f with
which gears an insulated toothed wheel g fixed on a vertical spindle h. Another
rack with ratchet teeth is provided within the carrier, with which engages a spring i

page_text: furnished with a knob k. At each side of the carrier are fixed the rails which
receive the positive current through the terminal T, the band o, and the screw p,
and transmit it to the carrier by means of two copper brushes m.
The negative
carbon bolder is formed by the standard q fixed upon the carrier which, like the
other, also runs on four friction rollers. The rack's fixed to the carrier gears with
the wheel t at the opposite side to the rack f of carrier d. The wheel t is fixed on
the same insulator and on the same spindle has the wheel g so that the carbons
are brought together or separated according as this spindle is turned in the one
or other direction. The carrier runs on the two rails u which are in electrical
connection with the carrier by the brushes v, fixed at either side of the carrier.
The negative current passes through the rails u, the screw w, the copper band,
and the terminal T, the rails u being fixed on insulating plates z and insulated
from the rails . Screws passing horizontally through the insulators z fix the
rails and other screws traversing the insulators vertically fix the rails 1, the
same screws securing the whole to the top plate a¹. 6' is a contact plate screwed
upon one of the rails u and serving to establish the current in the lamp imme-
diately the latter is placed in position in the projector where it rubs upon a copper
contact spring. The electric motor g arranged in a shunt, rotates the vertical
shaft h in one direction only, through a pinion c¹ fast on the vertical shaft of the
armature of the motor, then through a wheel d³, pinion e¹, and wheel f', the latter
being fixed on the shaft h, so that by this means a slight motion of the carriers
will correspond to a considerable movement of the armature. The spring barrel h'
gears with a toothed part of carrier r and tends to separate the carbons. On the
axis of the barrel is mounted the worm wheel together with the worm kl
whereby to regulate and maintain the tension of the spring. To the insulated
bracket is also fixed, besides the barrel and its worm, the hand motion consisting
of two bars m¹ connected together on the one hand by a cross-piece and on the
other by an axis about which the bars can pivot, these bars serving to support a
second worm n' which may be turned by hand by means of the insulated hand
wheel o. Beneath these two bars is mounted a spindle furnished with a detent pl
by turning which, by means of the handle q', it is caused to engage beneath one of
the two bars m¹ and so hold the worm n' in gear with the spring barrel at the
same time that the small point fixed in the cross-piece is separated from the
contact plates and thus breaks the current passing to the motor. By now turning
the hand wheel o' the separation of the carbons may be regulated by hand, but
when the detent p¹ is turned downwards the two bars m¹ together with worm n
fall by their own weight or are 'pulled down by a spring, whereupon the point pl
bears on the plate s¹ and the current is established in the motor, so that the
movement is rendered automatic. The relay t¹ is an electro-magnet in a shunt
and whose armature u is held back by a spring capable of being regulated for a
given electrical tension. It has for its object to send the current to the electric
motor g', or to short-circuit its armature according to the variations of tension.
All these parts are contained in a box ». Upon the positive carrier d is fixed a
rod carrying a tray w¹ to catch any ash and particles of carbon that may fall down
during the working of the lamp.
The operation of the lamp is as follows: The cables being attached to the
terminals T and T₁ the main current passes directly to the carbons, the electric
motor and the relay being placed in shunts, as illustrated in the diagram Figure 8.
When the carbons cease to touch each other, the tension is at a maximum, the
relay attracts its armature thereby establishing the current through the motor by
breaking the short circuit of its armature which thereupon revolves and brings the
carbons together until they touch, but the tension having then become very weak
the relay immediately ceases to attract its armature which falls back on the
contact a¹, thus short-circuiting the armature of the motor. At the same moment
the spring of the barrel ¹ acts in the contrary direction to the motion of the motor,
separates the carbons, and lights them, at the same time that the tension increases
up to, say, forty-six volts, for example, the relay being adjusted to attract at above

page_text: forty-six volts. Consequently at the smallest increase of tension the relay comes
into action, causes the motor to revolve and feed up the carbons a little, and then
immediately afterwards the relay lets go its armature, thereby stopping the motor,
at the same time that the spring barrel, which tends to separate the carbons, comes
into action. It will thus be seen that there is a continuous play to and fro of the
carbons, which is scarcely visible at the luminous centre, whilst the motor oscillates
slightly to and fro. Immediately the lamp is extinguished by the breaking of the
current, the spring barrel separates the carbons to the extent of a tooth of the
ratchet-toothed rack of the carrier d before referred to. When the carbons are
to be renewed, the carbon carriers should occupy their extreme positions that is to
say the negative carrier should be moved up to the stop y' by pressing on the
knob k of the detent spring i and so releasing the carriers. Another stop z¹ limits
the motion in the direction of their approach.
Dated this 5th day of June 1802
Improvements in Electric Search Light Apparatus.
I GASTON SCIAMA, Manager of the Firm of Bréguet of 19 Rue Didot Paris,
France, Electrical Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to improvements in electric search light apparatus, capable
of being manipulated electrically from a distance or directly by hand.
The apparatus comprises the optical part or projector; the operative mechanism;
the mechanism for distributing the electric current; and the lamp; and it is
illustrated in the drawings accompanying my Provisional Specification, wherein
Figures 1 and 2 are vertical sectional elevations of the optical part or projector and
its operative mechanism; Figure 3 is a diagram and Figures 4 and 4 are sectional
elevations and Figures 5 and 5A a plan and horizontal section on line c, c Figure 4 of
the manipulator; whilst Figures 6 and 7 are sectional elevations and Figure 8 a
diagram of the lamp mechanism.
The optical part comprises a parabolic crystal mirror differing essentially from
the spherical mirror or from the aplanatic mirror with spherical surfaces of unequal
radii heretofore used. The spherical mirror might be substituted for the parabolic
mirror, if constituted by a thin segment of a sphere of large radius, but in this case
the focal length being equal to the radius is very great and as the luminous intensity
of an object lighted diminishes as the square of the distance of the source of light
from the reflector, it is highly important to bring the focus as near as possible to
the mirror. The aplanatic mirror enables the focal distance to be diminished but
involves a mirror of great thickness especially at the edges and consequently of
great weight and a loss of light due to the double refraction which the luminous
ray must undergo in order to be brought parallel to the axis of the mirror.
Moreover the focal length of an aplanatic mirror is always greater than that of a
parabolic mirror of the same aperture. The parabolic mirror is, therefore, far
superior to the others as regards thickness, weight, and power of illumination.
Having found that, especially with horizontal carbons, the central zone of the
mirror is practically useless, a central aperture is made in the mirror with a view
to render more efficacious the ventilation of the silvered surface and enable the
luminous intensity to be very much augmented, to facilitate the manufacture of
the mirror, and enable the reflector the better to resist the air pressures due to the

page_text: discharge of cannon. The parabolic mirror whether apertured or not, throws a
luminous beam which is truly parallel to the optical axis when the source of light
is placed at its focus. In certain circumstances it may be desirable to spread the
beam in a given plane and this result is obtained by the interposition in the path
of the beam of a series of diverging plano-convex lenses fixed in a frame arranged
in the manner hereafter described whereby to spread the beam in any direction
-desired.
In Figures 1 and 2 of the drawings, the mirror i fitted in a carrier d and covered
with a cap is attached to the hood a of the projector by ears e so as to be easily
dismounted. The hood is closed at front by a plane glass j carried by a hinged
bezel. Four supports formed on the flange k of the hood serve to receive the
diverging lens carrier whose octagonal form adapts it to be attached in any
direction. To the underside of the hood is attached the box f containing the lamp
mechanism, the arrangement being such as to admit of the lamp being adjusted in
the direction parallel to the optical axis without interrupting the current, this
adjustment being effected by a screw turned by a hand wheel v. A polished
prism m whose surface on the side of the incident rays is convex and on that of the
emergent rays concave, throws the image of the arc on a ground glass screen and
enables the variations of the arc to be followed without opening the hood. A
shutter operated from the outside by a handle is provided for the emission of
optical signals. The hood a is supported by trunnions bin standards c rising from
a plate o running on four rollers and guided by a central hub that enters a socket
in the top of the pedestal q. An arrangement consisting essentially of a right-
angled prism mounted on one of the trunnions 6 permits of throwing upon a
voltmeter a small beam of light in whatever position the hood a may be and
notwithstanding that the voltmeter is fixed, the trunnion being for this purpose
bored axially so that the ray of light passing through it may fall on the prism and
be thence transmitted to the voltmeter.
The operative mechanism has for its object to enable the beam of light to be
projected in every direction for sweeping the horizon and it is designed to enable
these movements to be produced either directly by hand or from a distance and
either rapidly or gradually. The movement in altitude or of inclination, may be
effected directly by worm gear applied to one of the trunnions of the hood and
rendered fast or loose by a clutch so as to enable a slow or a sudden movement of
inclination as required. The projector is operated from a distance by means of an
electric motor through the medium of a spindle passing through the hub of
plate o and engaging by collars at its upper end with a stud on a lever w, y one of
whose arms is graduated to enable an initial upward or downward inclination of a
certain number of degrees to be given to the projector. The arm y is connected to
the hood a by a rod z and when w and y are rigidly connected by tightening a
key & the vertical motion of spindler causes a corresponding motion of the projector
or by loosening the key r the projector may be moved freely in any direction by
hand. The spindle is screw-threaded and traverses a nut in a skew-wheels in
gear with another skew-wheel on a spindle u provided with a hand-wheel. If an
electric motor a¹ actuating the spindle u be arranged within the base, movements
in altitude may be effected from a distance it being only necessary to provide a
device whereby to break the circuit when the spindler has attained either of its
extreme positions and avoid the burning of the motor which would occur were the
current in the same direction to be continued indefinitely. For this purpose two lugs
are provided at the lower end of rod that engage with the bell-crank lever g¹ which
a spring tends to hold in one of its extreme positions. The axis of this lever
carries a switch which according to the position of the lever bears on one or other
of the contact levers d¹ and breaks the circuit of the electro-motor a¹ every time
that the projector reaches one of its extreme positions at the same time that the
current for working in the opposite direction is established, the two contact levers
being connected by an insulated spring.
The mechanism for imparting the movement in azimuth comprises a worm

page_text: wheel capable of being made fast or loose on the hub of the movable plate o..
When loose, the plate o and consequently the whole projector can be turned
freely; when fast, the plate can be turned gradually by the operation of a worm
shaft u gearing with wheel, the operation from a distance being effected by an
electro-motor m" geared by an endless chain with the shaft u'.
The distribution of the current in the projector is effected as follows:-The main
leads or cables for the conveyance of the current are attached to the terminals n'
and in connection the one directly, and the other through the medium of a switch,.
with two brass rings p' fixed on a wooden base o' screwed to the pedestal top p.
The current passes, through the medium of the brushes in contact with rings pl,.
to the two binding screws s' fixed on the plate o and connected, by flexible cables,
either to the terminals of the lamp-box or of the lamp itself.
66
64
When the projector is to be controlled from a distance a manipulator is provided
whereby the current for the motors a' and m¹¹ is controlled, the connections between.
the source of the current, the manipulator, and the two motors being indicated
diagrammatically in Figure 3 whilst Figures 4 & 4ª show sections and Figures 5 & 5ª
plan and horizontal section of the manipulator. The manipulator comprises
iwelve keys, a circuit closer or switch, and resistances suitably connected to the
keys, its principle of action being as follows -When a current is about to be sent
through the motors by the closing of the circuit at the manipulator, the current.
passes directly through the field magnets whilst it only passes through the armatures
through the medium of resistances which are sufficient to prevent the setting of the
motors in motion. When, however, one or more of these resistances are short.
circuited, the notors rotate more or less rapidly. For this purpose there is
provided a plug switch S, two terminals B, B' for connection with the source of the
current, knobs labelled Upwards,' Downwards," "Left quickly," "Left
slowly," " Right quickly," "Right slowly," or distinguished by equivalent expres-
sions and which it is only necessary to depress in order to impart corresponding
motions to the luminous beam. The sectional and plan views shew the twelve keys
a1, a2, a³, to a¹, of which one extremity is mounted to oscillate freely on the rod t.
At the other extremity of the keys is fixed a contact-screw and an attachment.for
a spiral spring c connected at its other end to a fixed point which serves also for
the connection of the wires, as shewn in the cross-section. Below the contact-
screws of the keys are arranged flat contact springs 1, 2, 3, 7.0, 700, 207, 208, 200, 2.11, 2012,
the screws by which these springs are fixed serving also as binding screws for the
conducting wires. It will be seen that the keys a³ and a¹0 have no contact spring
beneath them but a contact-screw fixed in the top of the box, the object of these
two keys being to short-circuit the corresponding armature. At starting, it is
necessary to commence by breaking the short circuit of an armature and short-
circuiting a part of the resistance. With this object the keys a¹ a² a a7 a8 and a12,.
are provided with arms which bear at the same time on the keys a³, a*, a³, and
a³, al, all
Referring to the diagram, Figure 3, it will be seen that by pressing, for example,
the knob No. 1 ("Left quickly" in Figure 5) before the contact is established at
the spring, the arm of key a¹ will carry with it the key a and break the short
circuit. The current is then free to pass through the armature of the motor for
producing the movement in azimuth by following the path b, c, d, e, f, g, h, i, k l, m,
but the movement will not yet take place by reason of the resistances d, e, and k;
but immediately on the breaking of the short circuit, the key a³ which also partakes.
in the movement of a¹ comes in contact with the spring and thereby short circuits
In short, as soon
the resistance l, k, and the armature is thereupon put in motion.
as the key a¹ bears on the spring r¹ (and these three motions although successive
are nearly instantaneous) the resistance de will also be short circuited and the motor
will run at its highest speed. By pressing on the knob No. 2 it will be easily seen
that the same action will occur except that instead of ultimately short-circuiting
the resistance de, the portion se only will be short-circuited aud the action will
be slower. By pressing on the knobs 3 and 4 the operation is similar, except

page_text: that a current is sent in the opposite direction through the motor. By means of the
knobs 5 and 6 the motor by which the movements in azimuth are effected, is set in
motion in the one or other direction. It will be evident that both the electro-motors
may be set in action simultaneously by pressing the knob 5 or 6 and at same time
on one of the four others.
The lamp whether operated electrically from a distance or directly by hand is an
electric regulator with continuous current and horizontal carbons although the
system is equally applicable to a regulator with vertical or inclined carbons.
The lamp is illustrated in Figures 6, 7, and 8, and comprises the positive and
negative carbon holder, an electric motor, a spring barrel, and a relay. The
positive carbon holder is a standard a provided at top with a jointed clip b. It is
adjusted for height by a cam on a spindle c turned by a hand wheel so as to regulate
its position with regard to the negative carbon. The carbon holder is mounted on
a carrier d running on four rollers e and this carrier is provided with a rack f with
which gears an insulated toothed wheel g fixed on a vertical spindle h. Another
rack with ratchet teeth is provided within the carrier, with which engages a spring i
furnished with a knob k. At each side of the carrier are fixed the rails which
receive the positive current through the terminal T, the band o, and the screw p, and
transmit it to the carrier by means of two copper brushes m. The negative carbon
holder is formed by the standard 9 fixed upon the carrier r which, like the other,
also runs on four friction rollers. The racks fixed to the carrier gears with the
wheel t at the opposite side to the rack f of carrier d. The wheel t is fixed on the
same insulator and on the same spindle has the wheel g so that the carbons are
brought together or separated according as this spindle is turned in the one or
other direction. The carrier r runs on the two rails u which are in electrical con-
nection with the carrier by the brushes v fixed at either side of the carrier. The
negative current passes through the rails u, the screw w, the copper band a, and
the terminal T¹, the rails u being fixed on insulating plates z and insulated from the
rails l. Screws passing horizontally through the insulators z fix the rails u and
other screws traversing the insulators vertically fix the rails 1, the same screws
securing the whole to the top plate a'. is a contact plate screwed upon one of
the rails u and serving to establish the current in the lamp immediately the latter
is placed in position in the projector where it rubs upon a copper contact spring.
The electric motor g₁ arranged in a shunt, rotates the vertical shaft h in one
direction only, through a pinion c¹ fast on the vertical shaft of the armature
of the motor, then through a wheel d', pinion e¹, and wheel f', the latter being
fixed on the shaft h, so that by this means a slight motion of the carriers
will correspond to a considerable movement of the armature. The spring barrel h¹
gears with a toothed part of carrier and tends to separate the carbons. On the
axis of the barrel is mounted the worm wheel i¹ together with the worm k¹ whereby
to regulate and maintain the tension of the spring. To the insulated bracket lis
also fixed, besides the barrel and its worm, the hand motion consisting of two bars m²
connected together on the one hand by a cross-piece and on the other by an axis
about which the bars can pivot, these bars serving to support a second worm n¹
which may be turned by hand by means of the insulated hand wheel o'. Beneath
these two bars is mounted a spindle furnished with a detent p¹ by turning which,
by means of the handle q', it is caused to engage beneath one of the two bars m¹
and so hold the worm n' in gear with the spring barrel at the same time that the
small point fixed in the cross-piece is separated from the contact plate s¹ and thus
breaks the current passing to the motor. By now turning the hand wheel of the
separation of the carbons may be regulated by hand, but when the detent p¹ is
turned downwards the two bars m together with worm n' fall by their own weight
or are pulled down by a spring, whereupon the point r bears on the plate s¹ and the
current is established in the motor, so that the movement is rendered automatic.
The relay t' is an electro-magnet in a shunt and whose armature u' is held back by
a spring capable of being regulated for a given electrical tension. It has for its
object to send the current to the electric motor g¹ or to short-circuit its armature

page_text: according to the variations of tension. All these parts are contained in a box v¹.
Upon the positive carrier d is fixed a rod carrying a tray w¹ to catch any ash and
particles of carbon that may fall down during the working of the lamp.
The operation of the lamp is as follows: The cables being attached to the
terminals T and T¹ the main current passes directly to the carbons, the electric
motor and the relay being placed in shunts, as illustrated in the diagram Figure 8.
When the carbons cease to touch each other, the tension is at a maximum, the relay
attracts its armature thereby establishing the current through the motor by
breaking the short circuit of its armature which thereupon revolves and brings the
carbons together until they touch, but the tension having then become very weak
the relay immediately ceases to attract its armature which falls back on the
contact, thus short-circuiting the armature of the motor. At the same moment
the spring of the barrel h' acts in the contrary direction to the motion of the motor,
separates the carbons, and lights them, at the same time that the tension increases
up to, say, forty-six volts, for example, the relay being adjusted to attract at above
forty-six volts. Consequently at the smallest increase of tension the relay comes
into action, causes the motor to revolve and feed up the carbons a little, and then
immediately afterwards the relay lets go its armature, thereby stopping the motor,
at the same time that the spring barrel, which tends to separate the carbons, coines
into action. It will thus be seen that there is a continuous play to and fro of the
carbons, which is scarcely visible at the luminous centre, whilst the motor oscillates
slightly to and fro. Immediately the lamp is extinguished by the breaking of the
current, the spring barrel separates the carbons to the extent of a tooth of the
ratchet-toothed rack of the carrier d before referred to. When the carbons are to
be renewed, the carbon carriers should occupy their extreme positions, that is to
say the negative carrier should be moved up to the stop y' by pressing on the
knob k of the detent spring i and so releasing the carriers. Another stop z limits
the motion in the direction of their approach.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
=
1st. The combination and arrangement of parts of the projector with parabolic
mirror and means for operating the same as herein described and illustrated in
Figures 1 and 2 of the drawings.
2nd. In the optical part of a photo-electric apparatus, the employment of a
reflector apertured at the centre or other suitable point, and also an octagonal
diverging lens carrier for enabling the luminous beam to be spread in any direction
desired.
3rd. The arrangement within the fixed and revolving parts of the mounting of
all the parts for conveying the current to the lamp and for producing the two
movements in altitude and in azimuth, substantially as specified, so as to make the
projector independent of its base.
4th. In the herein described apparatus, the means for establishing electrical
communication between the fixed and revolving parts, consisting of brushes and
peripheral rings arranged as described.
5th. The arrangements herein described for transmitting motion from the motors
to the hood of the projector.
6th. In the herein described apparatus, the lever constructed of two adjustable
members for transmitting the movement in altitude.
7th. The automatic device for breaking the circuit of the motor imparting
the movement in altitude, whenever the projector reaches either of its extreme
positions.
8th. The herein described arrangement comprising a reflecting prism in com-
bination with an axially-bored trunnion for illuminating a volt-meter in any position
of the hood.

page_text: 9th. The hereinbefore described manipulating mechanism operating and con-
trolling the projector from a distance, substantially as specified.
10th. The mechanism constituting the lamp, consisting of the electro-motor, the
relay, and the spring barrel, in combination with carbon holder carriers arranged
and operated as described.
11th. The carbon holder carriers constructed and arranged to be operated as
described, and the means for limiting their motion, substantially as specified.
12th. The herein described arrangements for enabling the lamp to be operated
by hand in lieu of automatically.
Dated this 5th day of March 1894
By A. M. & Wm. Clark,
G. SCIAMA,
53, Chancery Lane, London, Chartered Patent Agents.