Improvements in Electric Lamps.
Year: 1889

page_text: Date of Application, 4th July, 1889
Complete Specification Left, 10th Mar., 1890-Accepted, 12th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in Electric Lamps.
I, HENRI PIEPER fils, Electrician, residing at No. 12, Rue des Bayards, Liege,
kingdom of Belgium, do hereby declare the nature of this invention to be as
follows:-
My invention relates to electric lamps in which the light is produced by means of
a carbon-rod being at one end in contact with two electrodes, so that, when the latter
are excited, the current will pass transversely through the carbon, i.e. vertically to its
length. The improvements are as follows.
Firstly, the electrodes are made movable and they are pressed independently of
each other against the carbon, in order to keep them in certain contact with the
same in case the carbon should burn away on one side more than on the other.
Secondly, the electrodes are made in the form of tubes open at both ends and
placed at an incline, so that a current of air will pass through them when they
become heated by the carbon, the said air-current preventing the electrodes from
being heated excessively.
Thirdly, the lamp is provided with means for switching it out of circuit automatically,
without interruption of the current, when the carbon is consumed, the said means
consisting in two contact pieces, one of which is located above the positive electrode
and electrically connected to the negative pole of the lamp, while the other is
arranged above the negative electrode and electrically connected to the positive
pole.
Fourthly, the carbon-rod is so formed or constituted that its central portion or
strip presents greater resistance to the passage of the current than the portions being
in contact with the electrodes; the purpose of this disposition being to obtain a
uniform temperature upon the whole path of the current through the carbon.
Dated 4th July 1889
J. H. JOHNSON & Co.,
Agents.
COMPLETE SPECIFICATION.
Improvements in Electric Lamps.
I, HENRI PIEPER fils, Electrician, residing at No. 12, Rue des Bayards, Liege,
kingdom of Belgium, 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 lamps in which the light is produced by means of
an electric circuit, a carbon-rod and two or more electrodes being in contact with
one end-surface of the said rod, so that when the electrodes are excited, the current
will pass transversely through the carbon, i.e. vertically to its length. The improve-
ments are as follows.
•
First. One or more of the electrodes is or are arranged to be capable of moving
with its or their points of contact lengthwise to the carbon, and it is, or they are
pressed (each separately if more than one is movable) against the end-surface of the
carbon, in order to keep the latter in certain contact with the electrodes in case it
should not burn away uniformly at all its points of contact.
Second. The electrodes, or any of them, are made in the form of tubes open at
both ends and placed at an incline, so that a current of air will pass through them
when they become heated by the carbon, the said air-current preventing the electrodes
from being heated excessively.

page_text: Third. The lamp having a movable electrode or electrodes, is provided with means
for switching it out of circuit automatically, without interruption of the current,
when the carbon is consumed, or if any portion of the same should break, the said
means consisting in contact-surfaces on the movable electrode or electrodes and other
contact surfaces arranged opposite thereto and each of which is conductively connected
to the pole of the lamp being of different denomination from that to which the
corresponding movable electrode is connected.
In the annexed drawings
Fig. 1 is a sectional elevation of a lamp having two electrodes and comprising
my improvements.
Fig. 2 is a section and fig. 2° an elevation of the carbon-rod used in the same.
Fig. 3 is a sectional view of a lamp with three electrodes, the central one being
vertical and stationary, the lateral ones horizontal and movable.
Fig. 4 shows in elevation and in section the carbon-rod for this lamp drawn to a
larger scale.
Fig. 5 is a skeleton view of a lamp with three electrodes whereof the central one
is vertical and movable, while the lateral ones are horizontal and stationary.
Figs. 6 and 7 are plans of modifications of the latter, comprising respectively three
and four horizontal and stationary electrodes.
Fig. 8 represents in plan an arrangement with two combined pairs of electrodes
which are all horizontal.
In fig. 1, A is the carbon and B C are the two electrodes. These are pivoted at b
and c to the respective posts G and H, which are fixed to the plate D, but insulated
therefrom. The post G is provided with the binding-screw E, and the post H with
the binding-screw F. The electrodes are drawn by springs r and against the end
of the carbon-rod, which in turn presses by gravity or, in addition thereto, by means
of a weight a against the latter. A current introduced at E will consequently pass
through the post G and the electrode B to the carbon A, and, after having traversed
the carbon, as indicated by the arrow 1, it flows through the electrode C and the
post H to the binding-screw F, the carbon being, in consequence, caused to become
incandescent at its end. In order to avoid the transmission of the current through
the pivots b and c, it is advantageous to connect the posts G and H with the respective
electrodes B, C by means of wires 9, h.
If with this arrangement the carbon is consumed unequally at its points of contact
with the electrodes, so that it becomes on one side shorter than on the other, the
electrode which is opposite to the point of greater consumption, will rise at its
contact-making end and thus remain in contact with the carbon, in whichsoever
position the opposite electrode may be at the time. By these means the formation
of sparks and the consequent burning of the electrodes, heretofore a great inconvenience
in lamps of this kind; is completely avoided.
For the purpose of keeping the ends de of the electrodes cool, the said electrodes
are perforated throughout their length so that they form tubes, and they are arranged
to be normally somewhat inclined upward from their point of contact. In consequence,
as soon as the electrodes become hot, an air current will arise in the perforation,
which produces refrigeration.
*
In view of causing the lamp to be switched out of circuit automatically, it is
provided with the contact-screws i k, carried by the respective insulated brackets i² k²,
and the ends whereof are opposite to the contact-points 6' c¹ of the electrodes and so
adjusted, that either electrode, on rising to a certain extent, will touch the corre-
sponding screw. The screw i being above the positive electrode B, is connected by a
wire with the post H and through the same with the negative pole of the lamp,
while from the other screw, k, a wire k¹ is conducted to the post G, which is in
connection with the positive pole. As long as the lamp is burning, the carbon keeps
the electrodes out of contact with the screws i and k. But if one of the carbon-parts,
for instance the part bearing on the electrode C, should break on a considerable
length, the spring puts the said electrode in contact with the screw. k, the current.
passes from the binding-screw E through the post G, the wire k¹, the screw k, the

page_text: electrode C and the post H to the screw F, the lamp being consequently switched
out of circuit. If the other part of the carbon breaks, the wire i¹ and the screw i
cause the switching out. A like effect is brought about by either shunt or by both
together, if the carbon is consumed or checked in its descent.
The carbon-rod A is made at the sides thicker than in the middle, as shown by
fig. 2. The said sides which are in contact with the electrodes when the lamp is
burning, consequently present less resistance to the current than the intermediate
part, the carbon becomes uniformly incandescent upon the entire portion acted upon
by the current, and a light of greater power is produced than by a carbon having
uniform resistance transversely. A like effect may be obtained if the carbon rod is
composed of three strips of carbon, the outer ones whereof are more conductive than
the middle one, and in this case the rod may be made of equal thickness at the sides
and in the middle.
The lamp represented by fig. 3 has the stationary electrode L and the two movable
electrodes CC, which are pressed against the carbon by weights n n'. The electrode L
supported by, and conductively connected to the plate D by the bows d, while the
electrodes C C¹ are pivoted to the respective posts H and H', which are screwed by
means of flanges m m³ to the plate D with interposition of insulating material and
connected together by a conductive bar m². To the plate D is conductively attached
the binding-screw E, and to the flange m the binding-screw F, which is insulated
from the plate D. A current entering at E will consequently pass through the
plate D, the bows d and the electrode L to the central part of the carbon, which
rests on the said electrode; at this point the current will divide into two branches,
one passing through the left-hand portion of the carbon, the electrode C and the
post H to the binding-screw F, while the other branch passes through the right-hand
portion of the carbon, the electrode C₁, the post H' and the bar m² to the flange m,
and ultimately also to the screw F. The carbon will consequently be exposed to the
current in a similar manner as in the first case, except that each half thereof is
acted upon by a branch of the said current, the purpose thereof being to obtain a
better utilization of the current especially in lamps which are to have great lighting
power.
Opposite to the points or contact-surfaces c¹ c³ of the electrodes C C₁ are arranged
the screws kk', screwed through the plate D, so as to be in conductive connection
therewith, and opposite to the points or contact-surfaces c³ and c¹ of the said electrodes
the electrode L is provided with the arms 112, the screws k k¹ and the arms 1112
being adjusted at a short distance from the respective contact-surfaces of the
electrodes C C when these are in their normal position. The result attained by this
arrangement is this: If the left hand corner of the carbon should break, the
electrode C will be brought into contact with the screw k by means of the weight n.
The entire current will consequently pass from the plate D through the parts k, C, H, m
to the binding-screw F, the lamp being thereby switched out of circuit. Á like
effect is produced by means of the electrode C and the screw k¹ if the right-hand
corner of the carbon should break. If the central part of the carbon should from
any reason become too short, the carbon will press the electrodes C C³ into contact
with the arms 11 12 of the electrode L, whereby the lamp is also short-circuited.
When, finally, the carbon is consumed, both electrodes C and C¹ will touch against
the screws kk and thus produce the short circuit.
As shown by fig. 4 the carbon-rod for this lamp has a thick strip in the middle,
designed to receive the current from the electrode L, and a thick strip or bead at
each side from which the two branch currents pass to the electrodes C C¹, the purpose
of this form being the same as that set forth relatively to the form of the carbon
of the lamp described above. But in this case also the lower resistance of the
portions of the carbon-rod being in contact with the electrodes may be attained by
making the central and the lateral strips of any kind of carbon which is in a
higher degree conductive than the carbon of which the intermediate portions are
formed.
The lamp represented in a skeleton view by fig. 5, differs substantially from the

page_text: foregoing one only in this that the electrode L is made movable and pressed by a
spring o against the central portion of the carbon-rod A, while the electrodes C°C¹
are stationary. The means for short-circuiting the lamp when the carbon is consumed,
or if a portion thereof breaks, consist in the arms p p extending from the electrodes C
and C downward and towards the electrode L, and in the arms fixed to the latter.
The cooperation of these parts will be obvious from the foregoing description.
Although in this lamp but one of the three electrodes is movable, the consumption
of carbon is quite regular because, as soon as the consumption begins to become less
on one side, the resistance opposed to the current at this side increases, and a greater
portion of the current passes over to the other side, the consumption being thereby
equalized again immediately.
It is evident that, instead of two electrodes C C¹, figs. 3 and 4, there may be three
or more, provided the carbon-rod be made with as many strips of low resistance as
there are electrodes. Thus fig. 6 shows in plan three electrodes C C C², connected
together by a ring M, and a carbon-rod composed of a thick central strip and three
ribs with thick strips or beads at their outer edges. Fig. 7 is a plan of four
electrodes C C¹ C² C³ connected together by a ring M, the carbon being made with
four ribs.
Fig. 8 finally shows in plan four electrodes connected in pairs to the positive and
the negative pole, the electrodes C and C¹ being united by the annular segment M³,
to which is attached the positive conductor, and the electrodes C2 C3 by the segment M²
connected with the negative conductor. The carbon in this case forms a cross with
thick strips or beads at the outer edges, but without such strip in the middle, as there
is no central electrode.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In an electric lamp, the combination of a carbon-rod, an electric circuit, two or
more electrodes in contact with one end surface of said rod, one or more of the said
electrodes being movable with its, or their, contact point or points lengthwise to the
rod and means for pressing the movable electrode or electrodes against the end-surface
of the same, substantially as described.
2. In an electric lamp, the combination of a carbon-rod, an electric circuit and
two or more electrodes in contact with one end of the said rod, o. e or more of the
said electrodes being tubular and inclined upward from their points of contact with
the carbon, substantially as specified.
3. In an electric lamp, the combination of a carbon-rod, an electric circuit, two
or more electrodes in contact with one end of the said rod, one or more of the said
electrodes being movable, means for pressing the movable elec' rode or electrodes
against the carbon-rod, contact-surfaces on the movable electrode or electrodes, other
contact surfaces arranged opposite thereto and each of which is conductively con-
nected to the pole of the lamp being of different denomination from that to which
the corresponding movable electrode is connected, substantially as hereinbefore set
'forth.
Dated the 10th dose of Mount 1000