IMPROVE- MENTS IN ELECTRIC LAMPS
Year: 1881

page_text: LETTERS PATENT to Richard Harrison, of Grainger Street West, Newcastle-
upon-Tyne, in the County of Northumberland, for an Invention of "IMPROVE-
MENTS IN ELECTRIC LAMPS."
PROVISIONAL SPECIFICATION left by the said Richard Harrison at the
Office of the Commissioners of Patents on the 14th October 1881.
RICHARD HARRISON, of Grainger Street West, Newcastle upon Tyne, in the
County of Northumberland. "IMPROVEMENTS IN ELECTRIC LAMPS."
My Invention relates to the construction and method of making and mounting
the carbonaceous filaments used for incandescent electric lamps, and to the provision
of means for automatically shunting the electric current from one to another of
these in case of failure of one, these means being applicable also to arc or other
kinds of electric lamps.
In preparing carbonaceous filaments for incandescent lamps I punch them out of
suitable cardboard or thick paper, using a punch having in its face a V-shaped
hollow so as to present two cutting edges. By the use of this punch I produce a
filament of triangular section much condensed by the punching pressure. The
filament is punched in curved form with its two ends widened out and having
eylet holes punched through them, and I prefer to punch it with a connecting
piece between these two ends so as to prevent the filament from being deformed in
its subsequent treatment, this connection being broken away after the filament is
carbonised and mounted. Into the cylet holes above mentioned I insert metallic
eylets such as are used for boot-laco holes and rivet them in, inserting under their
shoulders on both sides of the filament washers of soft paper or card. It is to the
metallic eylets thus inserted that after carbonising the filament I attach the
metallic connections, which may be strips of thin metal pinned to the eyelets, and
bent in trough form or corrugated to give them lateral stiffness. When these
strips have to be joined to platinum wires I bend the ends of the strips to
tubular form, insert the wires therein, and secure them by brazing or hard
soldering.

page_text: In order to provide for one light taking the place of another in case of extinction
of the latter, I provide the carbons in duplicate, and arrange in connection with
them a shunting apparatus of the following kind-I coil a few turns of the wire
for each carbon or set of carbons round an iron corc, so as to constitute for each
light a small electromagnet. In front of the poles of these magnets I mount an
armature so that it can be attracted to either and away from the other; and to
this armature I attach a spring which in the middle position of the armature bears
slightly against two contacts, one for each carbon or set of carbons. When either
has the greater part of the electric current passing through it, the electro-magnet
in that circuit being excited attracts the armature so that its spring makes a firm
contact for that circuit, but is taken out of contact for the other circuit. If then
this light should become extinguished its electromagnet loses its attractive power,
the elasticity of the spring causes the armature to move past its middle position,
and contact being thus made for the other circuit, the electromagnet belonging to
that circuit becomes excited and holds the armature and contact spring in the
position, making contact for that circuit and breaking it for the other.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Harrison in the Great Seal Patent Office on the 12th April
1882.
RICHARD HARRISON, of Grainger Street West, Newcastle-upon-Tyne, in the
County of Northumberland. "IMPROVEMENTS IN ELECTRIC LAMPS."
My Invention relates to the construction and method of making and mounting
the carbonaceous filaments used for incandescent electric lamps, and to the provision
of means for automatically shunting the electric current from one to another of
these in case of failure of one, these means being applicable also to arc or other
kinds of electric lamps.
In preparing carbonaceous filaments for incandescent lamps I punch them out of
suitable cardboard or thick paper, preferably such as is made from wood pulp,
using a punch having in its face a V shaped hollow so as to present two cutting
edges. By the use of this punch I produce a filament of triangular section much
condensed by the punching pressure. The filament is punched in curved form with
its two ends widened out and having eylet holes punched through them, and I
prefer to punch it with a connecting piece between these two ends so as to prevent
the filameut from being deformed in its subsequent treatment, this connection being
broken away after the filament is carbonized and mounted. Into the eylet holes
above mentioned I insert metallic eylets such as are used for boot lace holes and
rivet them in, inserting under their shoulders on both sides of the filament washers
of soft paper or card. It is to the metallic eylets thus inserted that after
carbonizing the filament I attach the metallic connections, which may be strips of
thin metal pinned to the cylets and bent in trough form or corrugated to give
them lateral stiffness. When these strips have to be joined to platinum wires I
bend the ends of the strips to tubular form, insert the wires therein, and secure
them by brazing or hard soldering.
In order to provide for one light taking the place of another in case of extinction
of the latter I provide the carbons in duplicate, and arrange in connection with
them a shunting apparatus of the following kind :-I coil a few turns of the wire
for each carbon or set of carbons round an iron core so as to constitute for each
light a small electro-magnet. In front of the poles of these magnets I mount an
armature so that it can be attracted to either and away from the other, and to this
armature I attach a spring which in the middle position of the armature bears
slightly against two contacts, one for each carbon or set of carbons. When either
has the greater part of the electric current passing through it, the electro-magnet
in that circuit being excited attracts the armature so that its spring makes a firm
contact for that circuit, but is taken out of contact for the other circuit. If then
this light should become extinguished its electro-magnet loses its attractive power,
the elasticity of the spring causes the armature to move past its middle position,
and contact being thus made for the other circuit, the electro-magnet belonging to
that circuit becomes excited and holds the armaturo and contact spring in the
position making contact for that circuit and breaking it for the other.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a section to an enlarged scale of the punch which I employ as above
described, the filament punched by it taking the triangular form, shown at a, a,

page_text: shews diagrammatically the shunting arrangement with carbons in duplicate; L,
L', are the line wires; L connects to a spring A which carries a spring B having on it
an iron armature M, and extending both ways so as to be lightly in contact with two
contact points D, D'. From these wires lead to the coils of two electro-
magnets E, E¹, and thence to the two carbon filaments C, C', which are both
connected at their other ends to the line L'. One of the magnets E is coiled with
wire somewhat larger and longer than the other so that it is a little more powerful,
causing the armature M to be attracted towards it. Thus the one carbon C being
in action, but C' not in action, the electrical current passing by the course L, A, B,
D, E, C, L', and exciting the magnet E, causes the armature M to be powerfully
attracted to the right, pressing one end of the spring B forcibly on the contact D,
while the other end of the spring is separated from the other contact D¹. If now
the carbon C should give way then the electrical current being arrested the
magnet E ceases to attract the armature M, whereupon the springs A and B recoiling
contact is broken at D and made at D¹, and the current now passes by the
course L, A, B, D¹, E¹, C¹, L¹, rendering the second carbon C¹ incandescent, and by
exciting the magnet El keeping the spring B forcibly in contact with D¹. The
wires from the magnets E, E', instead of being led directly to separate lamps may
cach bo led like the wire L to a similar shunting arrangement, thus connecting
to four lamps, as shewn diagrammatically at Fig. 4. Or again, by introducing
intermediate shunting arrangements connections may be thus made to 8, 10, or a
greater number of lamps.
It is obvious that the shunting arrangement, shewn in Fig. 3, as applied to
duplicate incandescent lamps might be applied to are or to other electric lamps
arranged in duplicate .
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
First. The construction and method of making and mounting carbonaceous
filaments for use in incandescent electric lamps, as herein described.
Second. The arrangement, substantially as herein described with reference to
Fig. 3, for automatically shunting the electric current from one electric lamp to a
second electric lamp in case of the failure of the former.
In witness whereof, I, the said Richard Harrison, have hereunto set my hand
and seal, this Twelfth day of April, in the year of our Lord One thousand
eight hundred and eighty two.
נד
HLADDISON