IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS OR LIGHTING APPARATUS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Alfred Shedlock at the
Office of the Commissioners of Patents on the 8th May 1883.
ALFRED SHEDLOCK, of the City and State of New-York, United States of
America, "IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS OR LIGHTING
APPARATUS ,,
The improvements in electric lamps forming the subject of this invention
comprise a new clutch or clamp for holding and releasing the upper carbon holding
rod, an electro-magnetic device for controlling the same, a new style of globe and
method of securing the same to the lamp, and a simple and effective means for
holding the lamp securely in position and for forming perfect connection between
the lead wires and the terminals of the lamp.
In the class of electric arc lamp having a smooth rod carrying the upper carbon
and by which the regulation of the arc is produce 1 by moving the upper carbon
only, it is essential to the perfect working of such lamps that the clutch or clamp
which holds the smooth rod should free the same at the right time gradually and
when the rod is at rest as regards longitudinal movement. To this end I utilize
the gripping properties of a spiral spring on a smooth rod, either by making the
springs smaller than the rod, thereby causing it to grip the rod by its resilience,
and releasing the rod by increasing the internal diameter of the coils of the spring,
by turning one or both of its ends which is or are free thus loosening the grip of
its various coils on the rod gradually until the weight of the rod and carbon is
just sufficient to overcome the clamping friction of the coils; or the spiral spring
may be made so that its action is reversed, that is, its resilience frees the rod, the
diameters of the coils when the spring is in its normal condition being larger than
the rod, it being caused to grip the rod by moving its end or ends in direction at
right angles to its axis thereby reducing the internal diameters of the coils.
"

page_text: To obviate the cause for the sudden changes in the arc, and the jumping of the
upper carbon in this class of lamp due to the movement imparted to the upper
carbon rod during the time the clutch or clamp is being opened to free the rod, I
so construct the actuating electro-magnet mechanism which carries and controls
the clutch, that the distance through which its armature moves greatly exceeds
that of the upper carbon, and that no perceptible movement is imparted to the rod
from the armature at the time the clutch is being opened to free the rod. To
accomplish this, the armature is suspended below the electro-magnet by means of
three or more links, and at its centre is secured the spiral spring clutch through
which the smooth rod passes. The armature acted upon by the magnet is caused
to partly rotate which compels the links to assume angular positions thereby
raising the armature and the rod a distance equal to the versed sine of the angle
assumed by the links; this raising of the armature separates the upper from the
lower carbon-and the spring clutch is opened when the armature is moving back
into its lowest position, that is, when the links are nearly vertical, so that the
upper carbon is virtually at rest when it is released to feed down towards the
lower carbon to keep the arc normal.
The globe is spherical with one opening only at its upper side, and to it is
secured a metal sleeve provided with bayonet slots adapted to slip over pins
provided therefor on the side bars of the lamp which support the lower carbon.
The whole of the. lower part of the frame is inside the globe, and is made of three
thin flat bars of metal to obstruct as little as possible the light rays.
L
The holder from which the lamp is suspended consists of a light frame adapted
to be secured firmly to the ceiling or otherwise, and provided with two pulleys and
two peculiarly shaped books into which pass two blocks which project from the
sides of the lamp and which form the terminals thereof. To the hooks are secured
the ends of the lead wires, and they may be joined together by a short circuit wire
and a closing spring, by means of which connection between them is broken when
the lamp is hung in position.
The lamp is fastened to the ends of cords which pass over the pulleys, and the
pulleys are so arranged that when the lamp is raised by means of the cords the
tops of the terminal blocks first come in contact with the forwardly inclined
bottoms of the hooks, and slide up the same until they come opposite openings in
the sides, into which they pass and fall down slots having inclined sides, thereby
forming perfect contacts between the hooks and the terminals of the lamp, upon
the strain of the cords being released. To remove the lamp for renewal of carbons
or for other purposes all that is necessary to do, is to pull on the cords to raise the
lamp until the terminal blocks pass over the extreme upper ends of the hooks when
upon lowering the lamp the blocks pass down the rearwardly inclined tops and
down the back sides of the hooks entirely clear of the same. By this arrangement
no current passes through the lamp when it is lowered, and all strain is removed
from the cords except when the lamp is being raised and lowered.
The lamp may be used without the holder, and be suspended and connected to
the lead wires in the ordinary manner-and the holder is also adapted to be used
with any other form of arc lamp.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Shedlock in the Great Seal Patent Office on the 7th November
1883.
ALFRED SHEDLOCK, of the City and State of New York; United States of
America "IMPROVEMENTS IN AND RELATING TO ELECTRIC LAMPS OR LIGHTING
APPARATUS "
.
My invention relates to electric lamps or lighting apparatus
In electric lamps of that class in which a smooth rod carries the upper carbon
and in which the regulation of the arc is produced by moving the upper carbon
only, it is essential to the proper working of the said lamps that the clutch or
clamp which holds the said smooth rod should free the same at the right time and
when the rod is at rest as regards longitudinal movement. To this end I utilize
the gripping properties of a spiral spring on a smooth rod, either by making the
spring smaller than the rod, thereby.causing the said spring to grip the rod by its
resilience the rod in this case being released by increasing the internal diameter
of the coils of the spring by turning one or both of its ends which is or are free,
thus loosening the grip of its various coils on the rod gradually until the weight
of the rod and carbon is just sufficient to overcome the clamping friction of the
remaining coils; or by making the spring so that its action is reversed, that is to
say, so that its resilience frees the rod, the diameter of the coils when the spring
is in its normal condition being larger than the rod, the spring in this latter case
being caused to grip the rod by bringing its ends nearer together to reduce the
internal diameter of the said spring.
To obviate the cause for the sudden changes in the arc, and the jumping of the
upper carbon, in this class of lamp, due to the movement imparted to the upper
carbon during the time that the clutch or clamp which holds the smooth rod is
being opened to free the rod, I so construct the actuating electro-magnetic
mechanism which carries and controls the clutch, that the distance through which
its armature moves greatly exceeds the movement of the upper carbon, and that
during the part of the movement of the armature when the clutch is being opened
to release the smooth rod, no perceptible vertical movement of the rod is caused
by the movement of the armature.
To accomplish this result the armature is carried by a plate which also carries
the spiral spring clutch or clamp through which the smooth rod passes; the said
plate is caused to move helically by suspending it by means of three links and the
armature is so acted upon by the electro-magnet as to cause the plate to partly
rotate on its centre, the said rotation causing the links to assume angular positions,
consequently the plate is raised equal to the versed sines of the angles, assumed
by the links. This raising of the plate separates the upper carbon from the lower
and the spring clutch or clamp opens when the plate is moving back into its lowest
position.
Considerable movement of the plate is required to free the smooth rod; the
actuation of the clutch, as will be readily seen, occurs when the hanging links
are moving a few degrees to or from the vertical, as the versed sine of such angular
movement is so small that no practical vertical movement is imparted to the upper
carbon.
My invention comprises other improvements in the construction of the lamp,
and also an improved holder adapted to hold the lamp securely in position and to

page_text: form perfect connection between the conducting wires and the terminals of the
lamp, all of which improvements will be hereinafter described.
In the accompanying drawings
Figure 1 is a vertical section of a lamp and holder constructed according to my
invention.
Figure 2 is a transverse section looking towards the electro-magnet on the line
xx Figure 1.
Figure 3 is a similar section looking towards the armature..
Figure, 4 is a side view of the upper part of the lamp partly in section.'
Figure 5 is a transverse section on the line y y Figure 1.
Figure 6 is a view of the upper carbon holder detached.
Figure 7 is a view of the spiral spring clamp and part of the upper carbon
holding rod detached and drawn to an enlarged scale.
Figure 8 is a view of the lower part of the lamp with the protecting globe.
Figure 9 is a front elevation of the lamp holder..
Figure 10 is a central section of the same..
Figure 11 is a perspective view shewing the manner in which the lamp is raised
to or lowered from the lamp holder.
The actuating, electro-magnet comprises a hollow core a, and a base-plate a¹ to
which are secured the three polar projections a² a² a², whose ends are inclined as
shewn at Figure 4.. Two insulated wire bobbins are placed on the core a the
one 'b of coarse wire being included in the arc circuit, and the other 6' of fine wire
in a derived circuit around the arc. The armature consists of a three-arm piece
of iron C provided with an internally threaded boss and set screw c¹ by means of
which it is secured to, and set in, the desired position (relatively to the polar
projections a a a²) on the frame c². This frame c² is suspended by means of three
links cc3c3 whose upper ends are connected to the base-plate a¹. The links have
ball bearings at their ends to allow the frames c³ to have a free helical movement
when the armature c is attracted by the poles of the electro-magnet.
Through the centre of the frame c* and the core of the magnet passes the upper
carbon-carrying rod or tube d provided with an adjustable ball-chuck d¹ for
holding the upper carbon d². In a recess in the centre of the frame c² is placed
the spiral spring clamp e formed simply of steel wire, which may be either round,
square, or flat coiled in a spiral so as to allow the rod d to slide, through it when
in its normal condition. The ends of the spring e project out radially as shewn at
ele Figure 7, and the sides of the recess in which the spring is placed in the
frame care cut away for the reception of the said ends of the spring, and a screw
cap c holds the spring in the recess. The end e¹ is held in its cut in the recess
so as to always move with the frame c², but the other end e² has considerable play
in its cut in the recess and passes through a hole in the arm f adjustably secured
to one of the polar projections a³, so that as the frame c³ moves, the spring e is
caused to grip the rod d and raise it and the carbon d² with it. This end e² is
provided with a few coils e³ to make it sufficiently flexible not to interfere with
the movement of the frame c³ after the spring clamp e has gripped the rod d.
To control the movement of the frame c the latter has two stops c³ c which
come in contact with the arm f. In most cases the weight of the parts just
mentioned with the resilience of the spring e e³ is sufficient to oppose the attraction
of the magnet on the armature e, when the current is normal to cause the lamp to
work properly, but, if desired, an extra regulating spring may be used to assist in
forcing the armature c and frame e into their lowest position.
It is evident that by simple modifications of construction the spring clamp may
be caused to grip the rod d when in its normal condition, and to release the rod
when the armature and frame c² are in the lowest position
The electro-magnet is inverted as shewn, and its base-plate a¹ is secured to, the
plate g of the frame of the lamp; this plate g is of insulating material and is
secured to the ring h which is connected to the side bars h¹ h¹ hand is provided
with a projection h² forming the negative terminal of the lamp. To the lower

page_text: ends of the side bars h¹ h' h' is secured the ring h³, and the lower carbon d³ is held
in a chuck hat the lower end of the bent bracket arm h³ which is held to the
ring hs by means of a bolt and thumb screw he, the said bolt being much smaller
than the hole. through which. it passes to allow the lower carbon 'd³ to be set
vertically under the upper carbon d²
The improved method I employ for supporting the globe i which has only one
opening, consists of the metal ring fitting in the said opening and the wire
netting connected to the lower end of the ring by the ends of the wire being
fastened in holes made in the ring i¹. The globe i is supported principally by the
netting which entirely surrounds it with the exception of the opening, the whole
being held up by means of bayonet slots is formed in the upper edge of the ring i¹.
and pins projecting from the ring h³ of the frame. To ensure perfect fitting of
the wire netting on the globe, and to produce perfect and more intimate contact
between the glass and the wire, the netting may be first made and placed in a
suitable mould or former and the glass globe blown therein.
The positive terininal of the lamp consists of a block secured. to the plate gand-
having a projection ; diametrically opposite to the negative terminal h. In the
body of the plate g is placed a spring k secured to the terminal h² and having its
free end above the terminal ; when in its normal position. A flange k¹ on the top
of the tube & comes in contact with an insulated plug on the spring / when the
tube is in its lowest position and before the chuck d¹ comes sufficiently close to
the chuck h for the arc to pass between them, thereby forcing the free end of the
spring k on to the terminal.; and thus short circuiting the lamp...This short
circuiting spring k may also be closed by means of the thumb screw k³ if it is.
desired to cut out the lamp for any purpose when in working position.
5.
The lamp is suspended by the terminals h² and j'in the holder; which consists of
a suitable frame-work composed of the top piece of wood and side pieces ¹ of
metal tubing. To the top are secured the two pulleys over which pass the
cords fastened to the rings h and which screw respectively into the
terminals h and j. When it is desired to use the lamp without the holder. the
main conducting wires may be secured to these rings h and j. At the lower. ends
of the side pieces are securely fastened the two similarly shaped metal
catches mm; these catches are each formed as shewn at figure 10, that is to say,
with a vertical back m', a forwardly inclined bottom and front 'm² with 'an
opening ms, a central slot m* with tapering sides, and with a rearwardly inclined
top m³.
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:
The pulleys 12 are so arranged that when the lamp is raised into position by
the cords 13 13 the projections h³ and j first come in contact with the forwardly
inclined bottoms m² as shewn by the dotted circle z; Figure 10, and then slide up
the fronts until they reach the openings m³ when they swing therein and fall down
the slots m; upon the strain on the cords 13 13 being released, as shewn by the
dotted circle they wedge into the tapering sides of the slots m' and the weight
of the lamp ensures perfect electrical connection between the catches m m.and the
terminal projections h² and j. When it is desired to lower: the lamp it is first
raised up by the cords ³ ³ until the projections h² and j pass over the extreme
upper ends of the catches m m, then upou lowering the lamp the projections pass
down the rearwardly inclined tops as shewn by the dotted circle 22, and finally
down the vertical backs m¹³ clear of the catches m'm.
To complete the circuit when the lamp is removed from the holder, the positive
end of the conducting wire is fastened to one of the side pieces, and this by
means of the insulated wire n passing down the other side piece is connected to
the spring n' placed in the catch m and forms perfect electrical connection-there-
with when the lamp is out of the holder, but it is pushed away therefrom, by the
end of the projection h³ striking the insulated plug n² as shewn at Figure 1 thus
causing the current to pass through the lamp when the latter is placed in the
holder. The current leaves the holder by the negative end of the conducting wire
connected to this side piece U. The wire n may include a resistance equal to that

page_text: of the lamp so that the resistance in the main circuit remains constant whether the
lamp is in or out of the holder.
'
na n³ are braces for holding the 'catches m m the proper distance apart.
The electric current enters the lamp by the projection j; passes through the coil b
one end b² of which joins j, and leaves the coil by the other end 63 which is fastened
to the flange of the tube o; it then passes up this tube. and down the rod o¹ and
from this rod by the metallic brush of which rubs against the inside of the tube d
it passes to the upper carbon d³ from thence to the lower carbon d³ up the side
bars h' of the frame, and out by the negative terminal projection h². The rod o!
may be insulated from the tube o and the end 65 carried up the tube o and
connected to the top of the rod o³ if it is desirable not to have the enclosing tube
included in the circuit. .The.object of making the sliding electrical connection in
the inside of the tube d by means of the brush o³ is to preserve the outside of the
tube smooth so as not to interfere with the proper working of the spring-clamp e
Heretofore it has been the practice to use spring rubbers against the outside of the
tube, which causes the same to be roughened by the small arcs often formed between
such sliding connections.
A portion of the current passes through the fine wire coil b¹, which forms a
branch circuit around the arc and acts on the well known differential principle
A case surrounds the working parts of the lamp to exclude dust and the like
consisting of a bottom piece p secured to the side bars h' and a cylindrical body p'
which is adapted to slide down out of the way when it is desired to manipulate
any of the working parts. The hole in the bottom p is much larger than the tube d
and a washer of leather or other suitable material p³ just fits the tube d to allow it
to slide freely therethrough, this washer is held against the bottom p by the guard p³
but is free to move laterally with the tube so as not to interfere with the free
working of the same.
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I claim :-
:
First. The combination, with a round rod, of a spiral spring-clamp surrounding
the same, having its coils closely wound and its free ends projecting at right angles
to its axis, and means substantially as described, whereby the free end or ends of
the spring are moved transversely to the axis, and its coils thereby caused to
contract to firmly grip the rod, and to expand to release the same, as set forth.
Second. In combination, a spiral spring-clamp, a carrying plate for the same
adapted to move helically, a smooth.rod or tube passed through, and upheld by, the
spring, and a stop to close the spring to grip the rod when the plate commences to
move, substantially as set forth.
Third. In combination, an inverted electro-magnet, an armature attached to a
frame supported by hanging links, a smooth carbon-carrying rod or tube passing
through the frame and magnet, and a clamp carried by the armature plate adapted
to uphold the rod or tube by coming in contact with a stop, but to release the same
when the frame is in its lowest position, substantially as set forth.
Fourth. In combination, the spring-clamp e el e², the tube d, the frame c³
adapted to be moved in a helical path, and the adjustable stop f, substantially as
set forth.
Fifth. In combination, the electro-magnet a a¹ a² b b', the armature c, the frame c²,
and the links c³ c³ c³, substantially as set forth.
Sixth. In combination, the frame c³ provided with an opened side recess, the
spring clamp e, the rod or tube d, the screw cap cand the stop f, substantially as
set forth.
Seventh. In combination, the electro-magnet a a¹ a³ 6 b¹, the armature c, the
frame c², the links c³ ³ c³, the spring clamp e, the rod or tube d, and the stop f
substantially as set forth.
Eighth. In a frame for arc lamps, the combination of the ring h, the side bars
hhh, the lower ring h³ and the adjustable bracket arm h³ provided with the
chuck h* for holding the lower carbon d³, substantially as set forth.

page_text: Ninth. In combination, the globe i, the wire netting. supporting the globe, the
ring provided with the bayonet slot ³ ³ ³ and the pins on the ring h³ of
the frame, substantially as set forth.
Tenth. In combination, the terminals h³ and j, the spring k provided with the
insulating pin k², and the rod or tube d provided with the flange k¹, substantially
as set forth.
Eleventh. In combination, the tube d, the rod o' provided with the connection
brush o³ and the enclosing tube o, or insulated conductor 66, substantially as set
forth.
Twelfth. The spring clamp e having the bent end e¹ and the end e² provided with
the spring coil ea, in combination with the smooth rod or tube d, substantially as
set forth.
Thirteenth. An electric lamp-holder consisting of insulated pieces of metal
forming the terminals of the circuit wires, each having a straight side and a central
slot with an opening at the other side, into which the terminal projections on the
lamp enter when the lamp is raised to a certain height, and guide-points over
which the terminal projections pass to allow them to pass down the straight sides
when the lamp is raised to a greater height, substantially as set forth.
Fourteenth. In combination, the catches mm, the wire n, the spring n¹, the
terminal projections h³ and j of an electric lamp, and the raising cords 13 13, substan-
tially as set forth.
In witness Whereof I the said Alfred Shedlock have hereunto set my hand
and seal this Third day of September in the year of Our Lord one thousand eight
hundred and eighty three.
חות IT
ATTNDONE
ALFRED SHEDLOCK.
L.B.)