IMPROVE- MENTS IN INCANDESCENT ELECTRIC LAMPS
Year: 1882

page_text: 10.
mis.
LETTERS PATENT to Lorentz Albert Groth, K.G.V. Civil Engineer and Managing
Director of The Universal Inventors and Patentees Financial Company
Limited 30 Finsbury Pavement London E.C for an Invention of "IMPROVE-
MENTS IN INCANDESCENT ELECTRIC LAMPS". Communicated to him from
abroad by Alex Bernstein, of Boston in the County of Suffolk and State of
Massachusetts, United States of America
€ 1
t:
PROVISIONAL SPECIFICATION left by the said Lorentz Albert Groth at
the Office of the Commissioners of Patents on the 20th December 1882.
LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Managing Director of the
Universal Inventors and Patentees Financial Company Limited, 30 Finsbury
Pavement London. E.C. "IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS'
A communication to me from abroad by Alex Bernstein, of Boston in the County
of Suffolk and State of Massachusetts United States of America
1.
J
more
This invention relates to improvements in Incandescent Electric Lamps and has
for its object the construction of an incandescent electric lamp which will be m
durable than those heretofore, in use and more economical in the production of
light by rendering the, light giving carbon capable of withstanding the action of
strong currents so as to avoid the disintegration which gradually takes place in
carbon filaments of high resistance. In order to obtain this desired effect, I make
use of a hollow carbon cylinder as the light giving part of the lamp, thereby
obtaining a large light, giving surface in proportion to a cross section of the carbon
and a large volume of light.
**
"
The success of, lamps of this kind does not only depend upon the way in
which the carbon cylinder is made, but also upon the arrangement of the
conducting wires and the proper construction of these wires themselves. The
invention consists of an incandescent electric lamp in which the light giving
part is made of a hollow cylindrical carbon or carbons, which are supported
by socket pieces of solid carbon. One of the conducting wires is rigidly applied

page_text: to one of the carbon socket pieces of the light giving part, while the other
conducting wire is made flexible, so as to provide for expansion or contraction
of the light giving carbon and admit the use of the strong currents without
detriment to the lamp. The lamps as well as the hollow light giving carbons
in the lamps may be arranged in different combinations, so that stronger out
door lights and small lights for indoor use may be conveniently arranged in the
same electric lighting circuit.
At the interior of a glass globe, which is evacuated by the usual approved
appliances, is arranged the light giving carbon which is made of a hollow cylinder
and supported at the ends of the socket-pieces, or blocks of solid carbon. The light
giving carbon as well as the conducting wires are secured to the carbon socket-
pieces and by means of suitable carbonaceous cement.
The conducting wires enter the globe either at one end through the neck of the
same, or at the opposite ends.
One of the conducting wires is made rigid, while the other conducting wire is
made flexible, by being composed of a large number of thin wires. This is the
essential feature which appears in every form of my, improved lamp, as thereby the
light giving carbon is enabled to expand and contract without being liable to
injury and breakage, so that a current of considerably greater strength, can be used
without endangering the lamp, than with incandescent lamps having carbon
filaments of high resistance. One or more light-giving carbons may be employed
in the same lamp and different depositions of the same be made.. By means of a
switch of a simple construction which connects the flexible conductor to one of the
main line, either one of the rigid conducting wires can be connected to the other
end of the main line, so as to graduate thereby the length of the light-giving
carbon and regulate the light consequently without the use of artificial assistance,
so that the light always corresponds to the power expended.
The light giving carbons may also be arranged in multiple arc, in which the
hollow carbons are made of the same length and supported on a larger carbon block
at one end and by smaller blocks at the other end, to which latter the flexible
conducting wires are applied.
It is evident that in lamps of this kind, the light emitted by application of the
same current will only depend on the length of the carbon, provided that the
resistance and the outside diameter of the hollow carbon are always the same.
Instead of using a lamp with a carbon one foot long, twenty four lamps with
carbons each half an inch long may be used in series, giving together the same
amount, of. light as the long carbon and thereby allowing an almost unlimited
division of the light.
The lamps are made with low resistance varying between 2 and 4 ohms when
cold, they requiring only small electro-motive force. This is a point of great
practical importance, as in the incandescent electric lamps of the construction
heretofore used, carbon filaments of high resistance were employed, which were
disintegrated by the action of the electro-motive force of the current required, even
if the filaments were not destroyed before by other constructive defects..
The low. electro-motive force employed in my improved lamps exerts no
disintegrating effect and consequently ensures a considerably longer duration of
the lamps..
A large number can be placed in series, a switch being provided with every
lamp, by which the lamps can be directly connected so as to extinguish the light.
Almost an endless variety of dispositions may be made, so that in. the same
electric lighting circuit, lamps of larger light giving power for out door lighting
and at the same time smaller lights for indoor lighting may be combined without
any practical difficulties..

page_text: $.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lorentz. Albert Groth in the Great Seal Patent Office on the.
20th June 1883.
LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Managing Director of The
Universal Inventors and Patentees Financial Company Limited 30 Finsbury
Pavement London E.C. "IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS"
A communication to me from abroad by Alex Bernstein, of Boston in the County
of Suffolk, and State of Massachusetts, United States of America.
This invention relates to improvements in Incandescent Electric Lamps and has
for its objects the construction of an incandescent electric lamp which will be more
durable than those heretofore in use and more economical in the production of
light by rendering the light giving carbon capable of withstanding the action of
strong, currents so as to avoid the disintegration which gradually takes place in
carbon filaments of high resistance. In order to obtain this desired effect, I make
use of a hollow carbon cylinder as the light giving part of the lamp, thereby
obtaining a large light giving surface in proportion to the cross section of the
carbon and a large volume of light
.
The success of lamps of this kind does not only depend upon the way in which
the carbon cylinder is made, but also upon the arrangement of the conducting
wires and the proper construction of these wires themselves.
The invention consists of an incandescent electric lamp in which the light giving
part is made of a hollow cylindrical carbon or carbons, which are supported by
socket pieces of solid carbon. One of the conducting wires is rigidly applied to
one of the carbon socket pieces of the light giving part, while the other conducting
wire is made flexible, so as to provide for expansion or contraction of the light
giving carbon and admit the use of strong currents without detriment to the lamp.
The lamp as well as the hollow light giving carbons in the lamps may be arranged
in different combinations, so that stronger outdoor lights and small lights for
indoor use may be conveniently arranged in the same electric lighting circuit.
In the accompanying drawings which fully illustrate the invention
Fig. 1. represents a vertical central section of the improved incandescent electric
lamp
Figs. 2. 3. and 4 are vertical central sections of modified constructions of the
same.
+
Figs. 5 and 6 are horizontal section's respectively on lines x x and y. y. Figs 1
and 3
Fig. 7 shows the disposition of different sizes of lamps in one éléctric lighting
circuit
Similar letters of reference indicate corresponding parts
A in the drawings represents a glass bulb or globe which is évacuated by the
usual approved appliances.
At the interior of the glass globe A is arranged the light giving carbon B which
is made of a hollow cylinder and supported at the ends by the socket pieces or
blocks of solid carbon C and D. The light giving carbon B as well as the
conducting wires E and F are secured to the carbon socket pieces C and D by
means of suitable carbonaceous cement
The conducting wires E and F enter the globe A either at one end through the
neck of the same as shown in Fig 1 or at the opposite ends of the globe as shown in
Figs 2, 3, and 4,
One of the conducting wires E is made rigid while the other conducting wire F
is made flexible by being composed of a large number of thin wires. This is the

page_text: essential feature, which appears in every form of my improved lamp as thereby the
light giving carbon is enabled to expand and contract without being liable to
injury and breakage, so that a current of considerably greater strength can be used
without endangering the lamp than with incandescent lamps having carbon
filaments of high resistance. One or more light giving carbons B may be
employed in the same lamp and different dispositions of the same be made
In Fig. 4 the different light giving carbons are placed in series and supported
by solid intermediate carbon blocks C¹ D' The flexible conducting wire F
is connected to the socket piece D at one end while rigid conducting wires are
connected to the remaining carbon blocks. By means of a switch of simple con-
struction which connects the flexible conductor to one end of the main line, either
one of the rigid conducting wires can be connected to the other end of the main
line, so as to graduate thereby the length of the light giving carbon and regulate
the light consequently without the use of artificial assistance, so that the light
always corresponds to the power expended. The light giving carbons may also be
arranged in multiple arc as shown in Fig. 3. in which the hollow carbons are made
of the same length and supported on a larger carbon block at one end and by
smaller blocks at the other end, to which latter the flexible conducting wires are
applied
L
It is evident that in lamps of this kind the light emitted by application of
the same current will only depend on the length of the carbons provided that the
resistance and the outside diameter of the hollow carbon are always the same.
Instead of using a lamp with a carbon one foot long twenty four lamps 'with
carbons each half an inch long may be used in series giving together the same.
amount of light as the long carbon and thereby allowing an almost unlimited
division of the light.
The lamps are made with low resistance, varying between 2 and 4 ohms when
cold' they requiring only small electro motive force. This is a point of great
practical importance, as in the incandescent electric lamps of the construction
heretofore used carbon filaments of high resistance were employed which were
disintegrated by the action of the electro motive force of the current required, even
if the filaments were not destroyed before by other constructive defects.
The low electro motive force employed in these improved lamps exerts no
disintegrating effect and consequently, ensures a considerably longer duration of the
lamps
717
A large number can be placed in series, a switch being provided with every
lamp by which the lamps can be directly connected so as to extinguish the lights
The diagram Fig 7 represents the arrangement of different lamps in one electric
lighting circuit, of which N° 1 represents a lamp with three light giving carbons in
multiple are which lainp is of large light' giving power, while N° 2 shows the
division of the light into three lamps connected in multiple arc. No 3 a con-
centration of the action of the current on two lamps having long carbons, and
No 4 shows a division by replacing each lamp by two lamps having each a carbon
of one half the length as that of the lamps in N° 3.
In this manner almost an endless variety of dispositions may be made so that'
in the same electric lighting circuit lamps of larger light giving power for outdoor
lighting, and at the same time smaller lights for indoor lighting may be combined
without any practical difficulties
Having now described the nature of the said invention and the manner in which.
the same is to or may be carried into effect I would have it understood that what I
claim as 'new and desire to be secured by the within in part recited Letters
Patent is:
"L
"
First In incandescent electric lamps the combination of an evacuated glass bulb
or globe with a light giving part formed of a hollow cylindrical carbon and with
solid supporting carbon socket pieces to which the conducting wires are attached t
substantially as set forth.
"Second In 'incandescent electric lamps the combination with an enclosing glass.
** 10
DE

page_text: globe, of one or more hollow light giving carbons, of solid carbon socket pieces
supporting the light giving carbons and conducting wires applied to the socket
pieces, one of the conducting wires being rigid, the other flexible to provide for the
unequal expansion and contraction of the light giving carbon tubes substantially
as set forth.
Third-In incandescent electric lamps the combination with an enclosing glass
globe of hollow cylindrical carbons supported by solid carbon socket pieces and
combined in series or multiple arc substantially as described:
Fourth In incandescent electric lamps the combination of an enclosing glass
globe with a number of hollow carbon tubes arranged in series, said tubes being
supported by solid carbon socket pieces at each end connected to a flexible
conducting wire and to rigid conducting wires respectively substantially as
specified.
Fifth An electric lighting circuit in which a number of incandescent electric
lamps having hollow light giving carbon tubes, are arranged either in series or
multiple arc and in such a manner as to concentrate the force of the current in one
lamp or divide it in a number of lamps substantially as specified
In witness whereof. I the said Lorentz Albert Groth have hereunto set my
hand and seal this nineteenth day of June in the year of Our Lord One
thousand eight hundred and eighty three.