Improvements in Electric Arc Lamps.
Year: 1897

page_text: Date of Application, 8th July, 1897-Accepted, 4th Sept., 1897
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
I, SIGMUND BERGMANN, of 572, First Avenue, New York City, United States of
America, 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, more especially to lamps in which
the arc is maintained within a small inner globe.
I so construct the frame of the lamp that the inner and outer enclosing globes
can descend so far below the base of the lamp as to readily permit the introduction
of new carbons, which in such lamps is attended with considerable difficulty,
because the outer globe is in the way, and has to be removed. This is objectionable
even when the globe is suspended below the lamp, as it requires considerable time
to attach and replace it with risk of broakage. According to my improved
construction this difficulty is quite overcome, and the lamp can be readily trimmed
without removing any of the parts, and without danger of breaking either the outer
or the inner globe.
I provide also a removable and adjustable electric contact making holder for the
upper carbon. Usually the upper carbon holder consists of a rod provided with
a screw or some equivalent device at its lower end, by which the upper carbon
is secured. This arrangement requires the small inner globe to be placed a con-
siderable distance below the operating mechanism of the lamp, in order to permit
sufficient vertical movement of the carbon securing device, between the top of the
small inner globe and the base of the lamp frame. By my improved construction
the vertical length of the lamp is considerably reduced. I also avoid the use of
a flexible conductor for leading the current to the upper carbon.
I also provide the inner globe with a cap so constructed on its outer surface,
as to seat itself in a ring seat provided in the base of the upper portion of the lamp,
and in such a manner that the cylindrical opening in the cap is directly in line with
the carbon and carbon holder. In lamps where the inner globe is situated lower
down, it is necessary to provide a cap having a considerable play in the globe, or
to place a movable washer in the cap, in order to accommodate it to inequalities
of the upper carbon. This portion of my invention relates to the construction of
a hollow cap for the inner globe, which does not conduct much heat.
My invention relates, also, to providing a telescopic electrical connection between
the upper portion of the lamp and the lower carbon holder, and various details of
construction as I shall describe referring to the accompanying drawings in which
similar numerals indicate like parts.
Figure 1 is a vertical section.
Figure 2 is an elevation of the base of the lamp, and the outer globe partly
owered.
Figure 3 is an elevation shewing the outer globe quite lowered.
Figure 4 is an enlarged view partly in section of the removable and adjustable
electric contact making holder for the upper carbon, and of the tube in which it

page_text: Figure 5 is a side view of the same shewing the contact springs.
Figure 6 is a plan of the cap for the inner small globe.
Figure 7 is a side view of the pivotted links which support the base of the
lamp.
1 is the base of the lamp which supports above it the regulating mechanism and 5
below it the tubes 2. To enlarged portions at the lower ends of the tubes 2 are
pivotted links 3. Within the tubes 2 and passing through the plate 1, are
tubes 4 provided at their upper ends-with stops 5 and carrying at their lower ends
a supporting yoke 6. Between the stops 5 on the tubes 4, and the top of the
plate 1, are helical springs 7. Within the tubes 4 are wires 8 which are provided
at their upper ends with small keys not shewn and connected at their lower ends
to a ring 9 in which is secured' the boss of the saucer 10 carrying the outer globe 11.
12 is the inner globe; 13 its cap; 14 a ring carried on, but insulated from, the
plate 1; the inner circumference of this ring is bevelled and the upper surface of the
cap 13 has a similar bevel so that when the parts are in the position shewn in
Figure 1, the top of the cap is seated in the bevel of the ring 14. Thus the
opening 15 in the cap 13 is brought in line with the upper carbon 16 which is
held and fed by the clutch mechanism 17. The lower carbon is carried in the
tubular portion 19 of the plate 20, and secured by the screw 21 (Figure 2). The
plate 20 is carried by the yoke 6, which has offsets 22, engaging the pivotted:
links 3 when the parts are in thic position shewn in Figure 1.
Depending from and also insulated from the plate 1, is a tube 23, the upper end
of which is in electrical contact with the conductor 24. Within the tube 23 and
'making electrcal contact therewith is a wire 25 which is in contact at its lower end
with the supporting plate 20. This arrangement provides a telescopic electrical
connection between the base of the lamp and the conductor extending from it.
The saucer 10 and the outer globe 11 are supported by a rod 26 having lugs 27,
which normally rest in hollows 28 of the yoke 6. 29 is a nut securing the parts.
When it is desired to trim the lamp, the nut 29 at the base of the lamp, is first
rotated, this releases the hanging rod 26, which when rotated, permits the
lugs 27-27 to pass out of their seats 28, and through the yoke 6, and thereby
allow the outer globe to be carried down sufficiently far to clear the offsets 22-22
when in the position shown in Figure 1, and over which the pivoted links 3–3
take.
The links 3-3, are then moved by hand. This releases the yoke 6, and permits
the outer and inner globes and their supports, to descend to the positions shown
in Figure 3, leaving sufficient room between the top of the outer globe and the
door 30 in the tubular portion of the plate 20, to permit of the introduction of new
carbons.
The springs 7-7, surrounding the tubes 4-4, serve to cushion the downward
movement of both globes when the links 3-3 are released. After trimming, the
parts are first moved to the position shown in Figure 1, and the links 3-3 secured
by hand over the offsets 22-22, after which the outer globe and its support are
moved into position, and secured therein by rotating the nut 29.
Referring now to Figures 1, 4, and 5, 31 is a tube supported by a flange resting
upon and in electrical contact with the metallic spool 32, of the magnet 33.
Within this tube and freely movable therein and removable therefrom, is the
carbon holder 34 consisting of a cylindrical body portion 35 of sufficient size at it;
lower end 36 to receive the upper carbon 16. Within the tube 35 is pivotted a
dog 37 having its lower end 38 semi-cylindrical to fit on the carbon 16. The
upper end 39 is sloped to conform to the conical end 40 of an adjusting screw 41,
which has a milled head 42 and screws in a thread 43 cut in the body of the tube 35.
44 are contact springs arranged opposite to each other and secured to the tube 35 by
the screws 45, their lower ends have slotted holes 46 for screws 47. These springs
make contact with the tube 31.
In the normal use of the lamp, the circuit through the lamp is from conductor +

page_text: coil of magnet 3, conductor 33ª, metallic spool 32, tube 31, carbon holder 34,
through the intervening contact springs 44, carbon 16, carbon 18, plate 20, rod 25,
conductor 24, conductor
When the parts are in the position shewn in Figure 3, and the door 30 open,
the lower carbon can be removed through the door on releasing the screw 21. The
upper carbon follows the lower carbon downward, carrying with it the carbon
holder 34, which passes the clutch and reaches the position indicated at X, Figure 2;
that is, between the bottom of the plate 1 and the top of the cap 13, when the
inner globe is in its second position. At this point the carbon holder is taken in
the left hand and the screw 42 turned by the right hand, releasing the upper
carbon which descends through the door 30. A new upper carbon is now introduced
through the door 30, into the carbon holder and secured therein by turning
the screw 42 to clamp it. The holder then is pushed up into the tube 31,
past the clutch 17; at the same time a new lower carbon is passed through
the door 30, and the door is closed. The parts are then brought to the
position shewn in Figure 1. The carbon holder 34 is thus seen to be removable,
adjustable relatively to the carbon which it carries and also relatively to the
tube 31 by means of the adjustable contact springs 44, which may be considered
adjustable as they can be readily bent to exert more or less spring pressure as
desired.
In Figure 1 the cap 13 of the inner globe is shewn seated in the plate 14, but in
Figure 2 the cap is shewn in the second position. By this construction and that
of the upper carbon holder, I am enabled to produce a very short lamp, about
2 feet long, which is of considerable importance, as a short lamp can be used in
places where a long lamp, as commonly made, would not be suitable. I am also
enabled to dispense with a cap having lateral play in the top of the inner globe
or a floating washer. A cap with lateral play is objectionable, when it has too
much play the requisite atmosphere cannot be maintained in the globe, and when
a floating washer is used it is apt to jam. In the construction described there is
only sufficient play between the cap and the globe to permit the expansion of the
metal of the cap when it is heated. The cap consists essentially of a hollow
body 48, the air in which acts as a non-conductor; its flange 49, rests on top of
the globe 12. It is bevelled at 50 (Figure 2) to conform to the bevel 51 in the
plate 14. The construction of the cap 13, or of the plate 14 may be varied provided
that the cap seats itself in the plate 14, and preserves the allignment of the carbon,
and the opening for the carbon through the cap.
The drawings shew various other parts of the lamp, as for instance, the parts
relating to the clutch mechanism, the connection of the inner globe, etc., etc., to
none of which do I make any claim.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim in respect of an electric arc lamp is:-
1. A chamber enclosing the arc and having its top seated in that portion of the
lamp which supports the carbon feeding and regulating mechanism, this top
having an opening for the passage of the upper carbon, substantially as described."
2. The combination of an inner globe enclosing the arc, its hollow cap, having
its top valve-shaped, and a ring having a seat for the cap, substantially as
described.
3. In combination with the supporting frame of the lamp, a telescopic support
for the outer globe, a telescopic support for the inner globe and means of fixing
the supports, substantially as described.
4. in combination with the upper carbon and its directing tube, a carbon holder
comprising a cylindrical tube provided with means for securing the carbon, and
with adjustable springs for ensuring electrical contact between the directing tube
and the carbon holder, substantially as described.
•
5. In combination with the supporting frame, a pair of tubes having links

page_text: pivotted on their ends, a pair of tubes within the former, carrying a yoke provided
with offsets with which the links engage, and spring buffers on the inner tubes,
substantially as described.
6. In combination with the inner tubes referred to in the preceding claim, a
pair of wires within them carrying a support for the outer globe, and a releasing
device for the support, substantially as described.
7. The construction of electric arc lamp substantially as described and illustrated
by the drawings.