IMPROVEMENTS IN THE MANUFACTURE OF CARBON CONDUCTORS FOR ELECTRIC-LAMPS AND IN APPARATUS THEREFOR
Year: 1882

page_text: LETTERS PATENT to William Robert Lake of the firm of Haseltine Lake
& Co Patent Agents, Southampton Buildings, London, for an invention of
"IMPROVEMENTS IN THE MANUFACTURE OF CARBON CONDUCTORS FOR
ELECTRIC-LAMPS AND IN APPARATUS THEREFOR."-A communication from
abroad by Hiram Stevens Maxim, of Brooklyn, New York United States of
America,
PROVISIONAL, SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 3rd April 1882.
WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake, & Co. Patent Agents,
Southampton Buildings, London "IMPROVEMENTS IN THE MANUFACTURE OF
CARBON
CONDUCTORS FOR ELECTRIC LAMPS AND IN APPARATUS TREREFOR
"
[A communication from abroad by Hiram Stevens Maxim, of Brooklyn, New York,
United States of America.]
This invention relates to the manufacture of carbon conductors available for use
in incandescent electric lamps. Such conductors, as is well known have a slender
thread-like stem with enlarged clamping ends. As it is desirable that these strips
should all be of exactly the same quality and size it has been usual to cut them by
a die from flat sheets of paper or wood in the form of flat strips with widened ends,
but when plastic carbonizable compounds are used for making the carbon, it is very
difficult to obtain any considerable number of strips of even approximately the
same size and resistance by any of the old methods employed, such as moulding and
then carbonizing, or by cutting out the strips from a hard mass of carbon.
This invention is designed to avoid these difficulties in the manufacture of carbon
conducting strips of an equal width or diameter from plastic compositions, and
consists in a continuous process of forming the said conducting strips, and in the
devices employed therein.
In carrying the said invention into practice I provide a stout frame-work
supporting a cylinder which is similar in many respects to that of the ordinary
pipe press, or the modified form of the same commonly used in the formation of

page_text: carbon pencils for arc-lamps; a plunger is connected with the piston and arranged
to work in the cylinder and there is a pipe or other opening for the introduction
into the cylinder of the plastic material used. I provide a nozzle through which
the material is forced. Attached to this nozzle is a die with an adjustable aperture
and consisting of a head with a screw-threaded portion and a flange, a rings fits
around the bead and is milled or provided with handles by which it may be readily
turned from side to side; crank-levers are pivoted to pins in the stationary head.
Plates are provided capable of a radial movement in dovetailed grooves in the
head. The crank-levers are slotted at both ends by which slots they are connected
with the ring and plates respectively by means of pins. The aperture of the die
or nozzle is directly in the centre of the head so that as the plates are caused to
slide in or out, the extent of the aperture is varied. The movement of the plates
is effected by turning to one side or the other the ring by which the levers are
turned and the position of the plate shifted.
The operation of the above described devices is as follows. A quantity of a
plastic carbonization compound of the desired kind is introduced under the plunger
in the cylinder through the pipe. The compound is kept hot and soft by any
convenient source of heat, such as a steam jacket or a burner. The ring is then
turned so that the die or nozzle is opened to its full extent and steam introduced
above the piston causing the plunger to force out the compound in the cylinder
through the die.
When a desired amount has been forced out the ring is turned
to reduce the size of the aperture in the die to its smallest area so that the mixture
now issues in a fine thread. When the length of this is equal to that desired for
the carbon strip, or slightly greater, the ring is again turned to enlarge the
aperture. By this means a continuous strip of the compound is produced having
enlargements at intervals. As this issues from the press it is cut up in lengths the
points of division being at the middle of the enlargements. The sections will thus
be composed each of a slender strip with enlarged ends and these may then be bent
into any desired shape, packed in sand or in a muffic and baked as in the usual
process of manufacturing carbon electrodes.
The materials ordinarily employed for making the carbons are finely powdered
graphite, or retort carbon, and a cohesive substance such as copal, or coal tar. The
ingredients and their proportions however may be greatly varied and other known
compounds employed with the sanie results.
I would also state that the means for enlarging or contracting the die, may also
be greatly varied the form described being only one of several which I contemplate
using.
Instead of turning the ring by hand, automatic devices may be employed to
regulate the size of the die, it being important to observe in the construction and
application of such devices, that the changes in size of the apertures shall be
sufficiently slow to form a gradual taper from the enlarged to the contracted
portions of the conducting strips.
It will be seen that by the above process homogeneous and efficient conductors
may be obtained in great numbers at a slight cost while the die which forms a part
of this invention, may be readily applied to the carbon presses now in use, without
making any important alterations therein.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Robert Lake in the Great Seal Patent Office on the
3rd October 1882.
WILLIAM ROBERT Lake; of the firm of Haseltine, Lake, & Co, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN THE MANUFACTURE' OF
CARBON CONDUCTORS FOR ELECTRIC-LAMPS, AND IN APPARATUS THEREFOR".
A communication from abroad by Hiram Stevens Maxim, of Brooklyn; New York,
United States of America,
This invention relates to the manufacture of carbon conductors for use in
incandescent electric lamps. Such conductors, as is well known, have a slender
thread-like illuminating portion with enlarged clamping ends. As it is desirable
that these strips should all be of exactly the same quality and size, it has been
usual to cut them by means of a die from sheets of paper or wood, in the form of
flat strips with widened ends, but when plastic carbonizable compounds are used for
making the carbon, it is very difficult to obtain any considerable number of strips
of even approximately the same size and resistance by any of the methods of
manufacture heretofore employed, such as moulding and then carbonizing, or by
cutting the strips from a hard mass of carbon.
This invention is designed to avoid the difficulties heretofore experienced in the
manufacture of carbon conducting strips of an equal width or diameter from plastic
compositions, and the said invention consists in a continuous process of forming the
said conducting strips, and in devices or apparatus therefor.
In the accompanying drawing is illustrated the improved apparatus for carrying
on the said process..
Figure 1 is an elevation partly in section of the said apparatus.
Figure 2 is a plan, drawn to an enlarged scale, of a device forming a part of the
said apparatus
Figure 3 is a side elevation of the saine
Figures 4 and 5 are illustrations of the carbon conducting strips. Figure 4 shews
two views of a portion of Figure 5 enlarged.
A is a strong frame. B is an ordinary hydraulic or steam press cylinder con-
taining the piston E and provided with ports or conduits C, D, for introducing
steam or water above and below the piston-G is a cylinder similar in many
respects to that of an ordinary pipe-press, or the modified form thereof commonly
used in the formation of carbon pencils for electric arc lamps, F is a plunger con-
nected with the piston E and arranged to work in the cylinder G. H is a pipe or
other passage for the introduction into the cylinder G of the plastic material to be
used for making the carbons K is a nozzle through which the material is forced.
Attached to this nozzle is a die, with an adjustable aperture; a convenient form of
this device is represented in Figures 2 and 3 and is constructed as follows, that is
to say, R is a head with a screw-threaded portion S and a flange 0.
L is a ring
fitting around the head the head R and milled or provided with handles by which
it may be readily turned in one direction or the other, M, M, are crank levers
pivoted to pins n in the stationary head R. N, N, are plates capable of a radial
movement in the dove-tail grooves in the head R. The crank levers M are slotted
at both ends and are connected with the ring L and plates N, N, respectively by
means of pins 1, 2, passing through their slots. The aperture of the die or nozzle
is directly in the centre of the head R so that by sliding the plates N in or out the
extent of this aperture is varied. The adjustment of the said plates is effected by
turning in one direction or the other the ring L, whereby the levers M are moved
around their pivots and the said plates are moved in or out according to the
direction in which the ring L is turned.
The operation of the above described devices or apparatus is as follows, that is to
say a quantity of a plastic carbonizable compound of the desired kind is intro-
duced under the plunger in the cylinder G through the pipe. H, this compound

page_text: being kept hot and soft by a steam jacket or by a burner p or by other convenient
means. The ring L is then turned so that the die or nozzle is opened to its full
extent and steam or water is introduced above the piston E and the pressure on
this piston causes the plunger F to force the compound in the cylinder G through
the said die. When the desired amount of this compound has been forced out, the
ring L is turned to reduce the size of the aperture in the die to its smallest area
so that the mixture now issues in a fine thread. When the length of this is equal
to that desired for the carbon strip or slightly greater, the ring L is again turned
to enlarge the said aperture. By these means a continuous strip of the compound
is produced having enlargements at regular intervals as illustrated in Figure 5. As
this strip issues from the press, it is cut into lengths, the points of division being
at the centre of the said enlargements. Each section will thus be composed of a
slender strip with enlarged ends, and these sections may then be bent into any
desired shape, packed in sand or in a muffle and baked as in the usual process of
manufacturing carbon electrodes.
The materials ordinarily employed for making the carbons according to the said
invention are finely powdered graphite or retort carbon and a cohesive substance,
such as copal or coal tar. The ingredients and their proportions however may be
greatly varied; moreover the means described for enlarging or contracting the die
may be considerably varied, for example, instead of turning the ring L by hand,
automatic devices may be employed to regulate the size of the aperture in the said
die, but in the construction and application of such devices care must be taken that
the changes in size of the apertures shall be sufficiently slow to form a gradual
taper from the enlarged to the contracted portions of the conducting strips.
It will be seen that, by the above process homogeneous and efficient conductors
may be rapidly produced at a slight cost, and the die which forms a part of this
invention may be readily applied or adapted to the carbon presses now in use
without making any important alterations therein.
Having thus fully described the said invention and shown in what manner the
same may be conveniently and advantageously carried into practice I wish it
understood that I claim-
First. The improved process or method of manufacturing carbon conductors for
incandescent lamps from plastic carbonizable substances, which process or method
consists in forming a continuous strip of alternately enlarged and slender portions,
dividing the said strip into equal lengths each of which lengths has enlargements
at its ends, and carbonizing these lengths or pieces, substantially as set forth.
Second. The combination, with a carbon press-cylinder, of a nozzle or die having
a variable aperture, substantially as above set forth and for the purpose specified.
Third. The combination of a carbon press, cylinder, a nozzle or die, and means
for varying the aperture of the said die, whereby a continuous strip of plastic
material whose cross sectional area is different at different parts thereof may
be expelled from the press, substantially as set forth and for the purpose
specified.
Fourth. The combination with a carbon press cylinder, of a die composed of a
centrally perforated stationary block and adjustable plates or slides, arranged to
vary the size of the aperture through which the material is expelled, substantially
as set forth and for the purpose specified.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Third day of October in the year of our Lord One
thousand eight hundred and sighty trea