Improvements in and relating to Electric Lamps or Lighting Apparatus.
Year: 1890

page_text: Date of Application, 8th Aug., 1890
Complete Specification Left, 8th June, 1891-Accepted, 8th Aug., 1891
Improvements in and relating to Electric Lamps or Lighting
Apparatus.
1, ALFRED LYSTER SHEPARD, of 8 West Kensington Gardens, in the County
of Middlesex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to electric arc lamps or lighting apparatus, and is designed
to improve the construction and working of the same.
The first part of my invention relates to that class of arc lamps known as motor
lamps, in which the operation of the carbons is effected by means of an electric
motor, the working of the motor being controlled by a relay which operates two or
more contact points, some of which are fixed and some movable, as for instance one
or more movable tongues working in combination with fixed points of contact. The
said contact points conduct a current to the motor and cause it to move the carbons
according to the requirements of the lamp. In order to save the above-mentioned
contact points from being burnt and worn away by continual.sparking on the same
spot, and to keep them clean, I so arrange them relatively to each other that the
contact points which before were stationary are now caused to move or revolve
as the motor works, thereby continually presenting fresh surfaces to the above-
mentioned movable tongue or tongues, The rubbing action which takes place
between the points of contact keeps them clean, thus preventing the wearing of
the platinum or other contacts and the consequent deterioration in the quality and
quantity of light furnished by the lamps. I prefer to form the said contact or
contacts on the revolving or reciprocating part of the motor; for instance I use
one or more discs of insulating material of suitable dimensions, the periphery of
which is covered with a strip of platinum or other refractory metal. The current
is conveyed to these strips by means of suitable brushes bearing lightly against
them. The current is then conveyed from the discs to the motor through other
brushes, the last named brushes being oscillated or moved by means of the relay so
as to make or break contact with the moving disc and consequently with the motor
according to the requirements of the lamp.
The second part of my said invention is more particularly designed for arc lamps
(of this description) for working with large currents, such as search lights for
military and other purposes. In this form of my improved lamp, I prefer to
employ a motor such as those of Gramme or Pacinotti, and to wind the field-
magnets of the motor with thick wire carrying the whole or a considerable
proportion of the main current and also with fine wire which carries a current
shunted from the arc, the armature being wound with small wire of suitable size.
The direction and duration of the current in the armature is controlled by a relay,
the regulating coil of which I prefer to wind as a shunt on the arc. The carbons are
carried in metal holders and can travel up and down a steel guide-rod fixed to the
base of the lamp and inclined at an angle of 20° to the vertical or other suitable
angle. I place parallel to this rod and in the same plane with it and the carbons,
a double threaded screw of the same length as the guide-rod. On the upper half
of this screw is a right hand thread and on the lower half a left hand thread (or
vice versa), by which the carbon-holders are caused to approach and to recede from
each other. This screw is constructed in such a manner that the upper half is
capable of being moved independently of the lower half, the latter being a tube
through which the upper half passes. Both carbon-holders are constructed so as
to be moved by hand on the guide-rod independently of the screw, when required.
The lower carbon-holder is, moreover, adapted to move in a lateral direction to

page_text: regulate the proper consumption of the carbon, by means of a small rack attached
to the sliding portion of the holder which carries the carbon, the said rack being
operated by a long pinion parallel to the screw and capable of being turned by hand
when required from outside the lamp by suitable means, such as a worm and wheel.
The current is conducted to the carbon-holders by flexible copper strips attached
thereto, the said carbon-holders being suitably insulated from the other parts of
the lamp.
The circuits and connections are so arranged that, when the carbons are apart,
a current flows through the fine wire on the field-magnets of the motor and also
through the relay, thus causing the tongue of the relay to make contact with one of
the stops or contact pieces so as to cause a portion of the current flowing through the
fine wire of the field, or through such portion or portious thereof as will afford
the required potential, to be deflected through the armature of the motor, in such a
manner that the said motor operates to bring the carbons together. As soon as the
carbons touch each other, the current flows through the thick wire of the field, and
the movable tongue being released by the short-circuiting of the relay, touches the
opposite contact, thus conveying a portion of the current flowing through the thick
wire of the field through the armature in the reverse direction, the poles of the field
still remaining the same; the armature therefore rotates in the reverse direction
and draws the carbons apart, thereby forming or striking the arc. When the arc
is of sufficient length, the current again flows through the relay, the tongue of
which is again moved so as to cause the motor to feed the carbons, and these
operations being repeated as required, effectually regulate the working of the lamp.
By these means I am enabled to effect the reversals of the motor with the aid of
only two contact points.
I sometimes place the relay or regulating coil and the contact in a box separate
from the lamp, being merely connected thereto by the necessary wires; this I do in
order to secure the said relay from shocks and jars which are likely to impair the
proper working of the lamp.
Dated this 8th day of Avanst 1800
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Lamps or Lighting
Apparatus.
I, ALFRED LYSTER SHEPARD, of 8, West Kensington Gardens, in the County
of Middlesex, 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 :-
My invention relates to electric arc lamps or lighting apparatus, and is designed
to improve the construction and working of the same.
The first part of my invention relates to that class of are lamps known as motor
lamps, that is to say, lamps in which the operation of the carbons is effected by
means of an electric motor, the working of the motor being controlled by a relay
which operates two or more contact points, some of which are fixed and some
movable, as, for instance, one or more movable tongues working in combination
with fixed points of contact. The said contact points conduct a current to the
motor and cause it to move the carbons according to the requirements of the lamp.
In order to save the above mentioned contact points from being burnt and worn
away by continual sparking on the same spot and to keep them clean, 1 so
construct them and arrange them relatively to each other that the contact points
which before were stationary, are now caused to move or revolve as the motor
works, thereby continually presenting fresh surfaces to the above mentioned
movable tongue or tongues. The rubbing action which takes place between the

page_text: Search
(of this description) for working with large currents, such as
military and other purposes, and comprises the improveinents hereinafter set
forth.
In the accompanying drawings I have shown how my said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a side elevation showing my improved device for controlling the
action of the motor for feeding the carbons.
Figure 2 is a diagram showing the electrical connections with the said motor.
Figure 3 is a side elevation,
Figure 4 a front elevation, and
Figure 5 an underside view, showing one form of my improved arc lamp.
Figure 6 is a vertical central section, drawn to an enlarged scale, showing details
of construction.
Figure 7 is a vertical central section, also drawn to an enlarged scale, showing a
slight modification of my invention.
Figures 8 and 9 are diagrams illustrating different arrangements of the electrical
connections, and
Figure 10 is a sectional elevation showing details of construction.
A is the frame which supports the lamp-mechanism; B is the motor; C is the
commutator; D, D' are the brushes.
Referring to Figures 1 and 2, E is a revolving disc or contact, which is fixed
upon the armature-shaft B' of the motor B; F is a movable or oscillating tongue,
which is pivoted at F to a bracket A' attached to the frame A, and which is
provided with the contact springs G, G. H is an electro-magnet included in the
main circuit of the lamp, and Jis an electro-magnet included in a shunt upon the
arc. K is a flexible conductor or brush, which bears against the rotary contact E
and serves to conduct the current to the brush D.
The revolving contact or disc E is preferably constructed of insulating material,
the periphery thereof being covered with platinum or other refractory metal. The
contacts G, G¹ of the movable tongue F are so arranged that one or other of them
will be caused to bear lightly against the periphery of the revolving contact E
when the tongue F is attracted by the corresponding magnet H or J. The current
will then flow in one or the other direction through the armature of the motor,
being conveyed through the brush D, the conductor K, the platinum or other metal
upon the disc E and the contact G or Gas the case may be. The tongue F will
be oscillated by the action of the magnets H, J so as to make contact between the
moving disc E, and one or other of the pieces G, G' according to whether the
magnet in the main circuit or that in the shunt is energized, thus regulating or
controlling the direction and duration of the current through the motor according
to the requirements of the lamp.
Referring to Figures 3 to 9, L, L' are the carbons which are supported in
holders M, MN is the regulating coil of a relay for controlling the working of
the motor. N is the tongue and N, N are the contacts of the said relay.
The carbon-holders M, M' are arranged to travel up and down a guide-rod Q
(preferably of steel) firmly secured to the base or frame A of the lamp, and
inclined at an angle of about twenty degrees to the vertical or at any other suitable
angle or the said guide-rod and the carbons may be arranged horizontally or
vertically if desired.
what term a
For effecting the feeding of the carbons by means of the motor B, I provide
"double-threaded" screw, that is to say, a screw having a right
hand thread on one part thereof and a left hand thread on the other part thereof,
so that, when it is rotated about its axis in one or the other direction, it will move
the carbons simultaneously towards or away from each other. This feed-screw is

page_text: arranged parallel to the guide-rod O and in the same plane with it and with the
carbons L, L. The said screw comprises an inner screw-threaded rod P which is
supported at its upper end in a bearing O secured to the upper extremity of the
guide-rod O, and which is further supported in a piece or block Q secured to the
said guide-rod O at or near the centre thereof. The said feed-screw also comprises
a hollow rod or tube R, which is provided with an external screw-thread and is
supported in suitable bearings on the frame A, and through which extends the
lower part of the rod P', the said rod P being so arranged that it can be moved
endwise independently of the tube R for the purpose hereinafter specified. The
tube R is provided with a right hand screw-thread and the rod P with a left hand
screw-thread as shown (or vice versa). The tube R is preferably supported by
means of a ball-bearing R', more clearly shown in Figure 10, upon the top of the
frame A, so as to diminish the friction and consequently the power required to
rotate the feed-screw. The screw-threaded rod P and the screw-threaded tube R
work in half-nuts M (Figure 6) in the upper and lower carbon-holders respectively.
A worm-wheel S is firmly fixed upon the said tube R, and is geared with a worm S¹
fixed upon the armature-shaft B₁ of the motor B. The said rod P is, moreover,
connected with the tube R by means of a clutch T (or in any other convenient
manner) to ensure their rotation together, whilst permitting their disconnection
when necessary, so that either of them can be rotated separately to alter the
position of or "focus" the arc. The half-nuts M² can be thrown into and out of
engagement with the screw-threads on the rod P and tube R by means of cams or
excentrics as shown in Figure 6 (or in any other convenient manner) to permit the
movement of the carbon-holders by hand on the guide-rod O independently of the
feed-screw when required. Anti-friction rollers 02 are mounted upon the carbon-
holders M, M and are adapted to bear against the guide-rod O so as to facilitate
the movements of the said carbon-holders thereon. In some instances, I use, in
place of the said wheels, suitable balls held in recesses in the inner surface of the
carbon-holders and running in grooves in the guide-rod.
The feed-screw P, R is, as above stated, so constructed that the upper half
thereof, that is to say, the rod P, is capable of being moved independently of the
lower half or tube K, the said rod, which is passed through the tube R, is connected
therewith by a pin or stud P₁ fixed in the said rod, and extending through an
elongated slot in one part of the clutch T, so that the rod P can move
longitudinally or endwise relatively to the tube R, but, when connected therewith
by the clutch, must participate in any rotary movement thereof. This capability of
independent movement of the upper portion of the screw, permits of the raising
of the upper carbon L, without the aid of the motor B, and the consequent striking
of the are in a more expeditious manner than is practicable by the movement of the
carbons under the action of the motor. For effecting the striking of the arc when
the carbons come into contact with each other, prefer to employ an electro-
maguct U, and I find it advantageous to secure this magnet to the underside of the
frame A, and to attach its armature to one end of a bent lever U pivoted at U² to
a bracket A' attached to the said frame. To the other end of this lever is attached
one end of a spring U³, the other end of which is attached to the frame A. The
rod P rests at its lower end in a recess in the end of a setting-up screw U provided
with a lock-nut U³. The coil of the magnet U is included in the main circuit, so
that, as soon as the carbons touch each other, the said magnet will turn the lever U
about its pivot and thus raise the rod P and form the arc. The feeding of the
carbons by the motor will then be effected as required.
I sometimes so arrange the armature of the electro-magnet U relatively to the
poles thereof that, with the normal current, the armature is not fully attracted;
therefore any excess of current will cause the armature to approach more closely
and thereby increase the length of the arc. I may, if desired, employ, in place of
the electro-magnet U, a solenoid having a movable core which is suitably connected
with the lever U.
The above described arrangement of electro-magnet or solenoid is intended for

page_text: In the
use in cases where the field-magnets are wound either wholly with fine wire as
hereinafter mentioned with reference to Figure 9, or partly with thick wire and
partly with fine wire as hereinafter mentioned with reference to Figure 8.
latter case,
1 sometimes utilize the current in the thick wire of the field-magnets
for effecting the striking of the arc. For this purpose, I may employ a movable
yoke actuated by the said magnets substantially in the manner described in the
Specification of Letters Patent dated 13th July A.D. 1888, No. 10,209, the said
movable yoke being connected in any convenient manner with the inner rod P. I
prefer, however, to place the whole or a portion of the thick wire beneath the lamp
and to utilize the current flowing through it for actuating a lever as above
described with reference to the drawings.
In this case,
can utilize the volts lost
in this winding, to furnish current for the armature as hereinafter mentioned with
reference to Figure 8.
To enable the lower carbon-holder M' to be moved or adjusted laterally to
regulate the burning of the carbons, so as to ensure the proper consumption of the
same, construct the said holder in two parts, one of which (M) is arranged to
slide freely up and down upon the guide-rod O, the portion M of the said carbon-
holder, which carries the lower carbon L', being free to move laterally to and fro
on the part M. A small rack V is attached to the said sliding portion M' of the
holder, and a long pinion or pinion-wire V₁, supported in suitable bearings, is
geared with the said rack. A worm-wheel V2 is firmly fixed upon the said pinion-
wire V at or near its lower extremity, and is geared with a worm Vs formed on or
firmly secured to a spindle V supported in suitable bearings in the frame A. This
spindle is provided with a milled wheel by means of which it can be turned by
hand from the outside of the lamp to move the part M in either direction through
the said worm V³, worm-wheel V2, pinion V₁, and rack V, and thus effect the
lateral adjustment of the lower carbon.
The carbon-holders are suitably insulated from the other parts of the lamp, and
the current is conducted thereto by means of flexible copper strips W, W.
I show in Figure 7, a different arrangement in which I connect the screw-
threaded rods P and R by means of a clutch arranged within the block Q and
composed of two sleeves T', T2 adapted to engage with each other, and connected
by pins T, T with the said rods P, R respectively. The upper sleeve T is formed
with slots T to receive the pin T³, so that the said sleeve can be moved up and
down relatively to the rod P for the purpose of disconnecting it from, and
connecting it with the sleeve T. For moving the said sleeve for this purpose,
I employ a lever Y pivoted at Y to the block and connected with the sleeve Ti
by a pin working in a slot in the said block. It is evident that, with this
arrangement, I can, if desired, employ an electro-magnet included in the main
circuit and arranged in any well-known or suitable manner so that, when the carbons
touch each other, it will raise the rod P and strike the arc.
In the form of my improved lamp shown in Figures 3 to 6, I prefer to employ a
motor such as those of Gramme or Pacinotti; and I sometimes wind the field-
magnets of the motor with a thick wire a, Figure 8, carrying the whole or a
fine wire b, Figure 8,
considerable proportion of the main current, and also with
which carries a current shunted from the are, the armature being wound with small
wire of suitable size. The direction and duration of the current in the armature
are controlled by a relay, the regulating coil N of which I prefer to wind as a shunt
on the arc. In the diagram shown in Figure 8, the regulating coil N is arranged on
one side of the tongue N1, and a regulating coil Z, included in the main circuit, is
arranged on the other side thereof.
The circuits and connections are 50 arranged that, when the carbons are apart,
a current flows through the fine wire on the field-magnets of the motor, and
also through the regulating coil N, thus causing the tongue N' of the relay to
make contact with the stop or contact-piece N, so as to cause a portion of the
current flowing through such portion or portions of the fine wire b as will afford the
required potential, to be deflected through the armature of the motor, in such a

page_text: manner that the said motor operates to bring the carbons together. As soon as the
carbons touch cach other, the current flows through the thick wire a of the
field-magnets, and the striking of the arc is effected either by the movement of
one part of the feed-screw independently of the other part thereof as above
described, or, in cases where no provision is made for such independent movement
of the upper half of the feed-screw, the arc is formed as follows, viz. :-The
current flows through the coil Z, and the movable tongue N' being released by
the short-circuiting of the regulating coil N, and being attracted by the coil Z,
touches the opposite contact N³, thus causing a portion of the current flowing
through the thick-wire a of the field to pass through the armature in the reverse
direction, the poles of the field still remaining the same; the armature, therefore,
rotates in the reverse direction and draws the carbons apart, thereby forming or
striking the arc. When the length of the are has increased sufficiently, the
current again flows through the coil N of the relay, the tongue N of which is
again moved so as to cause the motor to feed the carbons, and these operations
being repented as required, effectually regulate the working of the lamp. By
these merus, Į am enabled to effect the reversals of the motor with the aid of
only two contact points. It is evident that, if desired, the coil Z may be
dispensed with, and the tongue N be held by its spring in contact with the
piece N³, as shown in Figure 9, except when the said tongue is attracted to
the contact N by the coil N.
In some instances, I wind the field-magnets as indicated at b, b, Figure 9, with
fine wire included in a shunt on the arc, in which case I make use of the arrangement
for striking the are by a magnet in the main circuit as above described. When the
carbons are apart, the current flows through the coil N, which draws the tongue N'
up to the contact N2, so that a portion of the current flowing through the field is
diverted through the armature of the motor, which is thus caused to feed the
carbons towards each other. When the carbons touch each other, the main current
hen strikes the arc, the tongue N' being released, leaves the contact N2, and, should
the are not be sufficiently long, touches the contact N³, a portion of the current
flowing through the field is thus caused to pass in the reverse direction through the
armature, and the motor, being reversed, draws the carbons still further away from
each other. The motor is thus reversed as often as required, and the working of the
lamp properly regulated.
The lamp shown in Figures 3 to 6 is provided with a long bracket X of gun-
metal or other suitable material, to which is firmly secured the block or piece Q for
supporting the feed-screw, and through which the current is conducted to the upper
carbon. I find it advantageous to combine, with this bracket, or with a copper rod
or other suitable conductor in the lamp, a current indicator, whereby the strength
of the current can, at any time be readily ascertained. This indicator is conveniently
and advantageously constructed with a small magnetic needle which is suitably
pivoted so that its axis is parallel to the said conductor. The said needle, when no
current is flowing, is retained in the zero position by a small hair spring.
I sometimes place the controlling relay and the contacts in a box separate from
the lamp, being merely connected thereto by the necessary wires; this I do in order
to protect the said relay against violent shocks or jars which are likely to impair
the proper working of the lamp.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it understood that
I 'claim -
First. The combination, in a motor are kamp, of one or more movable contacts or
tongues controlled by an electro-magnet included in a shunt upon the arc, or by
electro-magnets included in the main and shunt circuits respectively, and a disc or
other contact-piece which is rotated or otherwise kept in motion by the motor so as
to continually present fresh surfaces to the said movable tongue or tongues,
substantially as hereinbefore described and for the purposes specified.

page_text: Second. In an electric arc lamp, an electric motor wherein the field-magnets are
wound partly with thick wire included in the main circuit and partly with fine wire
included in a shunt on the arc, or wholly with fine wirei ncluded in a shunt on the
arc, and wherein the direction and duration of the current in the armature are
controlled by a regulating coil included in another shunt on the arc, or partly by
such coil and partly by a regulating coil included in the main circuit, substantially
as hereinbefore described and for the purposes specified.
Third. The combination, with suitably guided carbon-holders, of a screw having
right and left hand screw-threads adapted to engage respectively therewith or
with nuts therein, and an electric motor for rotating the said screw in either
direction, controlled by a relay, substantially as, and for the purposes, above
specified.
Fourth. A feed-screw for an electric are lamp, having right and left hand screw-
threads and formed in two parts movable independently of each other, for the
purposes above specified.
Fifth. The combination, with a motor for feeding the carbons, of a screw-
threaded tube geared with the said motor and carrying one of the carbon-holders,
and a screw-threaded rod which carries the other carbon-holder and which extends
through the said tube and is movable independently thereof, for the purposes above
specified.
Sixth. The combination, with the motor, of the feed-screw geared therewith and
formed in two parts one of which is movable independently of the other, and an
electro-magnet or solenoid for moving this part of the said screw relatively to the
other, substantially as hereinbefore described and for the purpose specified.
Seventh. The modification of my invention, wherein I provide for utilizing the
current in the thick wire of the field-magnets for effecting the movement of one part
of the feed-screw relatively to the other part thereof, substantially as, and for the
purpose, above specified.
Eighth. The combination, with the motor for feeding the carbons, of the screw-
threaded rods, and the clutch for connecting the same so that they may be readily
disconnected to permit their relative adjustment for the purpose of altering the
position of the arc, substantially as hereinbefore described.
Ninth. The carbon-holder formed in two parts one of which is movable relatively
to the other to permit lateral adjustment of the corresponding carbon, and the other
of which is fitted upon a guide-rod, substantially as, and for the purposes, above
specified.
Tenth. The combination, with one of the conductors in an are lamp such as I
have hereinabove described, of a current indicator, substantially as, and for the
purpose, set forth.
Eleventh. The improved electric arc lamp constructed substantially as described
with reference to the accompanying drawings and operating as above specified.
Daud this 8th.
1001
LARS QUILT UT DUC LOU
A. L. SHEPARD.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.