Improvements in Electric Arc Lamps.
Year: 1895

page_text: Date of Application, 1st May, 1895
Complete Specification Left, 3rd Feb., 1896-Accepted, 7th Mar., 1896
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
I ROOKES EVELYN BELL CROMPTON, of Mansion House Buildings, in the
City of London Engineer, and EDMUND ARTHUR NORMAN POCHIN of Arc
Works, Chelmsford in the County of Essex, Engineer do hereby declare the
nature of this invention to be as follows:-
Our invention relates to various improvements in electric arc lamps and to new
combinations of details by which the construction of the lamps simplified and
cheapened and its durability and working improved.
The improvements relate chiefly to that class of lamp in which the movements of
the upper and lower carbon holders are controlled by various forms of chains,
bands or cords of a flexible nature and which we hereafter for convenience call
flexible connectors.
One form of our improved lamp consists of a foundation plate in which electro
magnetic mechanism in the form of a pair of electro magnets or of two pairs of
electro magnets or of a pair of solenoids arranged and placed so as to move a
vibrating lever carrying a brake. This brake controls the rotation of a drum or
pulley wheel on which are coiled a pair of flexible connectors one of which is
attached to the descending and the other to the ascending carbon holder so that
the rotation of this drum in one direction or the other controls the movements of
approach or the drawing apart of the carbons.
In connection with this combination we use various improved forms of details.
The guides by which the carbon holders and carbons are guided in line may consist
of two or more tubes open at one side so that the guiding part of one carbon
holder may slide and be guided within the slot in the tube and the other carbon be
guided by the external surface of the tube. In some cases we insulate these two
surfaces by covering the tube with vitreous enamel. In some cases we make
contact between the carbon holder and the internal surface of the tube by sliding
connections of a springy form similar to the tube scrapers used for cleaning the
tubes of boilers. In other cases we secure the same object by employing a bunch
of springy wire twisted like a mop head and forced within the tube.
We sometimes find it advisable in order to use tubes of small diameter which
thus cast smaller shadows to stiffen them at their half length by a framework
which conveniently takes the form of a diaphragm made either of metal enamelled
on its lower surface and through which the upper carbon passes or in some cases it
may be made of porcelain or glass or other transparent or partly transparent
material. For purposes of economising the consumption of carbon we sometimes
shape out the lower surface of this diaphragm immediately surrounding the hole
through which the carbon passes, in the form of a bell like cavity so as to hinder
the access of currents of air to the incandescent cone of the upper carbon. In
order to simplify the guiding arrangements for facilitating the removal for
cleaning purposes of lantern or globe and for giving access for the renewal of
carbons, we mount the lantern or protecting globe on a pair of guides fixed
parallel to and immediately outside the guide tubes above mentioned and we
arrange and place these tubes so that they can not only serve as a guide for the
globe or lantern but also for the cover which protects the working parts of the

page_text: lamp. It is sometimes found a great convenience to the lamp cleaner to be able to
release the catches which hold the globe up in position and then cause the globe or
lantern to descend without removing the hand from the catches. This we effect
by making the catches in two parts, the inner part having slotted keyhole shaped
apertures which hang on to suitably shaped pins, the outer part taking the form of
a pair of curved ears or handles and which serve the double purpose of locking the
inner portion in position on its pins.
Referring to the vibrating brake lever before mentioned we find in some cases it
permits of a more convenient and compact arrangement of the mechanism if we
make the axis of fibration of this brake lever at right angles to the axes of the
pulleys which the brake controls, instead of following the older practice in the
Patent granted to one of us No. 3339 of 1882 and to Crompton & Crabb No. 8063
of 1884, of making these axes parallel to one another.
One form of brake arrangement which we find it convenient to adopt consisting
of one turn of a flexible band round the brake cylinder having one end attached
to the above mentioned lever and having a weight attached to its free end, this
weight being so placed that when it is desired to allow of free movement of the
cylinder within the band, that end of the band which is attached to the lever is
lowered until the weight rests on a fixed part of the framework of the lamp, thus
the band is slackened and the brake cylinder released.
Although in some cases as flexible connectors we use metallic cords, chains or
thin metal bands all of which can act as conductors, in other cases we find it
necessary to use flexible connectors which are at the same time insulators. We
find that ordinary cords made of vegetable fibre gut, silk or such like materials are
liable to be attacked and become rotten by the action of the acid fumes of the arc.
For our improved flexible connectors when these are required to be conductors, we
use wires or bands and cover them with plaited asbestos or spun glass. In other
cases we make the flexible connector consist entirely of a flat plait made of
asbestos fibres or of spun glass. For metal connectors we use nickel or an alloy
of nickel with other metals which resists the oxidising action of the arc.
Dated the 1st dov of Mar 1905
R. E. B. CROMPTON.
Wm. Brookes & Son,
55 & 56 Chancery Lane, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
We ROOKES EVELYN BILL CROMPTON of Mansion House Buildings in the
City of London, Engineer, and EDMUND ARTHUR NORMAN Poems of Ara
Works, Chelmsford in the County of Essex, 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:-
Our invention relates to various improvements in electric are lamps and to new
combinations of details by which the construction of the lamps is simplified and
cheapened and its durability and working improved.
The improvements relate chiefly to that class of lamps in which the movements
of the upper and lower carbon holders are controlled by various forms of chains,
bands of cords of a flexible nature and which we hereafter for convenience call
Mexible connectors.
Que form of our inproved lamp consists of a foundation plate in which electro
magnetic mechanism in the form of a pair of electromagnets or of two pair of
cietro mugnets or of a pair of selenoids arranged and placed on to move s
vibrating lever carrying d brake. This bake mirul, the rotation of a drum or

page_text: pulley wheel on which are coiled a pair of flexible connectors one of which is
attached to the descending and the other to the ascending carbon holder so that
the rotation of this drum in one direction or the other controls the movements of
approach or the drawing apart of the carbons.
In connection with this combination we use various improved forms of details.
The guides by which the carbon holders and carbons are guided in line may
consist of two or more tubes open at one side so that the guiding part of one
carbon holder may slide and be guided within the slot in the tube and the other
carbon be guided by the external surface of the tube. In some cases we insulate
In some cases we
these two surfaces by covering the tube with vitreous enamel.
make contact between the carbon holder and the interual surface of the tube by
sliding connections of a springy form similar to the tube scrapers used for
cleaning the tubes of boilers. In other cases we secure the same object by
employing a bunch of springy wire twisted like a mop heal and forced within the
tube.
In
We sometimes find it advisable in order to use tubes of small diameter which
thus cast smaller shadows to stiffen them at their half length by a framework
which conveniently takes the form of a diaphragm made either of metal enamelled
on its lower surface and through which the upper carbon passes or in some cases it
may be made of porcelain or glass or other transparent or partly transparent
material. For purposes of economising the consumption of carbon we sometimes
shape out the lower surface of this diaphragm immediately surrounding the hole
through which the carbon passes, in the form of a bell like cavity so as to hinder
the access of currents of air to the incandescent cone of the upper carbon.
order to simplify the guiding arrangements for facilitating the removal for
cleaning purposes of lantern or globe and for giving access for the renewal of
carbons, we mount the lantern or protecting globe on a pair of guides fixed parallel
to and immediately outside the guide tubes above mentioned and we arrange and
place these tubes so that they can not only serve as a guide for the globe or
lantern but also for the cover which protects the working parts of the lamp. It is
sometimes found a great convenience to the lamp cleaner to be able to release
the catches which hold the globe up in position and then cause the globe or lantern
to descend without removing the hand from the catches.
This we effect by making the catches in two parts, the iuner part having slotted
keyhole shaped apertures which hang on to suitably shaped pins, the outer part
taking the form of a pair of curved ears or handles and which serve the double
purpose of locking the inner portion in position on its pins. Referring to the
vibrating brake lever before mentioned we find in some cases it permits of a more
convenient and compact arrangement of the mechanism if we make the axis of
vibration of this brake lever at right angles to the axes of the pulleys which the
brake controls, instead of following the older practice in the Patent granted to one
of us No. 3339 of 1882 and to Crompton & Crabb No. 8063 of 1884, of making
these axes parallel to one another.
One form of brake arrangement which we find it convenient to adopt consisting
of oue turn of a flexible band round the brake cylinder having one end attached
to the above mentioned lever and having a weight attached to its free end, this
weight being so placed that when it is desired to allow of free movement of the
cylinder within the band, that end of the band which is attached to the lever is
lowered until the weight rests on a fixed part of the frame-work of the lamp, thus
the band is slackened and the brake cylinder released.
Although in some cases as flexible connectors we use metallic cords, chains or
thin metal bands all of which can act as conductors, in other cases we find it
necessary to use flexible connectors which are at the same time insulators. We
find that ordinary cords made of vegetable fibre, gut, silk or such like materials
are liable to be attacked and become rotten by the action of the acid fumes of the
For our improved flexible connectors when these are required to be con-
ductors, we use wires or bands and cover them with plaited asbestos or spun glass.
Arc.

page_text: In other cases we make the flexible connector consist entirely of a flat
plait made of asbestos fibres or of spun glass.
For metal connectors we use
nickel or an alloy of nickel with other metals which resists the oxidising action of
the arc.
Figures 1 and 2 show side and end sectional views of a lamp. A and B are the 5
top and bottom plates which are framed together and held in position by 3 or 4
pillars or stays 2 of which are shewn at A' A². CC are the tubular guides
which serve to guide the upper and lower carbon holders c and c¹; these are
guided and held so that the carbons remain in correct alignment throughout the
whole of the travel of the carbon holders by having attached to one end of each 1
of them a prolongation d and d¹ the upper carbon holder e having the prolongation d¹
pointing downwards and fitted so as to be accurately guided within the tubular
guide C the prolongation being attached to the carbon holder by a narrow arm
which can slide within a slot in the side of the tubular guide C. The other
end of the carbon holder c, i.e. that shown to the right in the drawing is formed as 1
a fork so as to slide on and be guided by the outside of the tubular guide C on the
right hand side. Similarly the lower carbon holder c' is guided, the position of
the parts however being reversed, its prolongation within the tube being to
the right and its forked end embracing the other tubular guide being to the left,
see Fig. 7.
These two carbon holders are held and connected up to flexible cords or con-
nectors m m³, that which suspends the upper carbon holder being attached and
passing over from the left hand side of a pulley f, m' by which the lower carbon
holder is suspended passing up from the right hand side to a pulley e; these two
pulleys are secured to the same spindle and in cases where the flexible connector
is not insulated they must be insulated from one another; in this case the current
is led into the pulleys and hence to the carbons through the flexible connectors
As the
and the carbon holders by means of 2 springy rubbing contacts g g.
two connectors m and m' are attached to their respective pulley wheels on opposite
sides of the same axis it follows that a motion of rotation of these wheels
in one direction tends to separate the carbons and in the other direction
tends to bring them together. The upper carbon holder c is weighted to a
sufficient extent to supply the propelling power which tends to bring the
carbons into contact unless they are purposely held apart by the controlling
mechanism.
This controlling mechanism here consists of a band or cord brake consisting of
one turn of a cord one end of which is attached to a vibrating lever i at the
point; the band then passes, makes one or more complete turns round a brake
wheel R fixed to the same axis as the two pulley wheels e and f and is strained
by having a weight attached to its free end. This weight is shown at 1. This
weight is so adjusted on the cord that when the point of the vibrating lever
is in its lowest position or in that position at which it is intended that the cord
should cease to have a braking action on the wheel, the weight then rests on the
bottom plate but when the lever is in such a position that the point being raised
the weight is suspended, then the tension of the cord on the brake wheel i
sufficient to prevent the latter from revolving. The vibrating movement of th
lever is actuated by a pair of solenoids D D¹ which are provided with th
The winding
cores or armatures h h attached to the two ends of the lever i.
the solenoid or electromagnet D¹ to the right is arranged in series circuit with th
arc, whereas that on the left is in shunt circuit with the arc as will be well unde
stood by those accustomed to this class of arc lamp mechanism.
wound solenoid is shown on the drawing to the right and its core h¹
remote from the point so th
attached to that end of the lever most
when its core is drawn down the point is raised; this has the effect, first
lifting the weight in the dashpot and thus tightening the cord and as the moti
proceeds the tightened cord causes the brake wheel to revolve and carries with
the two pulley wheels and thus raising the suspension and carbon holder e c
This seri

page_text: lowering the lower carbon holder c¹. This separates the carbons and strikes the
arc. As the arc burns and the difference of potential between the two sides of
the arc increases the current through the shunt solenoid D causes its core and
corresponding end of the lever to be gradually depressed until a point is reached at
which the cord is slackened by the weight coming to the bottom of its dashpot and
hence a feed movement can take place.
Hitherto in arranging this class of mechanism, more especially in the inventions
for which Letters Patent were granted to both of us No. 15840 dated September 3rd
1892 it has been usual to arrange the vibrating lever with its axis parallel to the
axis of the rotating pulleys and rotating brake wheel, but in this case we adopt a
different arrangement and as will be seen in the plan view Figure 3 we arrange the
vibrating lever with its axis at right angles to the axis of our brake wheels. In
this way we are able to arrange our parts so as to make them much more accessible
and without overcrowding them are able to get them into a smaller diameter.
In the case which we illustrate the flexible connectors that we use act as
conductors and in this case it is necessary to insulate one of them at the point
where it passes through the lower foundation plate A but in some cases we prefer
to use flexible connectors which are at the same time insulators and in this case it is
unnecessary to insulate the two pulleys ef from one another and from the spindle,
but the current is conducted to the carbon holders through the tubular guides C C.
In this case the inner ends of the prolongations which pass inside the tubular
holders are formed with a sliding connection of a springy form consisting of a pair
of half tubes or four quarter tubes which spring outwards and press lightly against
the inner polished surface of the tubular guide, or we mount on one end of these
same prolongations a bunch or tuft of wires somewhat similar to those used on the
ends of the cleaning rods of guns or rifles. E shows a diaphragm plate which
serves the double purpose of connecting together and stiffening at the point very
near to the arc the two tubular guides which also can serve as a guide to the upper
carbon holder and as a means of preventing the excessive consumption of carbon by
limiting the excess of air to the incandescent surface of the upper carbon. This
we carry out by forming a portion of this diaphragm (as shown in Figures 45
and 6) into a bell like cavity the concave side facing downwards. This enables
the lower surface of our diaphragm E to be so placed as to be almost in a line with
the crater of the upper carbon or at a very slight distance the line of the surface
of the crater. The coned portion of the incandescent surface of the upper carbon
is therefore within the bell like cavity and only a limited supply of air can obtain
access to it. The lower surface of the diaphragm E is also in the best possible
position for acting as a reflector for throwing down such of the rays of light from
the arc as are directed towards the upper hemisphere and this is of great
importance when carbons of small diameter or when alternating currents are used.
This diaphragm E may be made of porcelain or other refractory insulating
material having a good reflecting surface or it may be made of enamelled metal
and in the latter case it is sometimes necessary to insert a bush of refractory
material in the aperture E¹ through which the carbon passes in the dished guide E
through which the carbon is guided with a sufficiently close fit to prevent access
of air.
In order to simplify the guiding arrangements for facilitating the removal of
the lantern or globe and for giving access to the lamp for the renewal of carbons,
we mount the globe II on a pair of guides G G which are fixed parallel to and in
the same line with the tubular guides C. C. As these guides are connected at the
top to the same foundation plate A and at the bottom to the same cross piece F
they tend to truss and stiffen the tubular guides and thus allow them to be made of
much smaller diameter than would be the case if this stiffening action did not
exist. This is of importance as it enables the diameter of C C to be reduced and
thus the shadow cast by them is reduced in size. The globe His arranged to
slide down the guides G G and when raised to its highest position is suspended and
held there by compound catches O O shown enlarged in drawing, Fig. 8. These

page_text: atches consist of two parts O and O¹ which can slide on one another to
xtent. These upper portions of the catches are provided with holes the lower
ortion of which is a circle and the upper portion is formed also as a part of a circle
f somewhat smaller diameter. The projecting pins p on which these catches rest
when the globe is raised are made of such size that the lower portion O¹ of the 5
catches can easily slide over the cylindrical portion of the pin p but a groove is
formed in the pin p in such a place that when the upper portion of the catch O is
pressed down the smaller part of the holder in the catch is pressed into a groove in
the pin p and thus serves to lock the catch; but it will be seen that the mere
action of raising the globe by lifting it by the two curved ears attached to 10
the upper portion of the catches, of itself unlocks the globe and enables the catches
to be pulled outwards and thus the globe can be allowed to slide down the guides G G,
until it rests upon the lower cross piece F.
It will be seen that the above described construction of lamp
the following features in combination :
characterised by
Carbons suspended by flexible suspenders pressing around pulleys mounted on
the same axis as the brake wheel which controls their movement.
This brake is characterised by its frictional bands slackening whenever a
suspended weight otherwise held up by it rests on a support provided for it.
Tubular guides for the carbon holders provided slotted on one side.
Carbon holders guided in said holders and kept in line by means of prolongations
set at right angles to one end of each holder and passing within the slot the other
end clasping the other guide.
An arrangement of vibrating leverage with its axis at right angles to that of
brake wheel and suspending pulley.
A diaphragm at or near arc serving the purposes of,
1. Stiffening the tubular guides.
2. Guiding lower end of upper carbon.
3. Acting as reflector.
4. Economising consumption of carbon.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In electric are regulator lamps the construction and combination or arrange
ment of parts substantially as herein described and shown in the drawings.
2. In are lamps in which the propelling force is gravity the combination o
flexible connectors with a feed mechanism consisting of a pair or sut of electro
magnets or solenoids actuating a vibrating lever the axis of which is at right angle
to the axis of the brake wheel on which it acts, substantially as and for the purpos
set forth and shewn by the drawings.
3. In are lamps in which the propelling power is gravity the use of flexib
connectors in combination with carbon holders guided in slotted tubular guid
substantially as herein described.
4. In arc lamps the use of locking clips for the globes or lanterns in which t
two parts are so arranged that the globe can be unlocked, detached and lower
by a single movement of the hands lifting the upper part of the clips substantia
as herein described.
5. In lamps in which gravity is the means of propulsion and the carbon hold
are suspended by flexible suspenders the use of prolonged holding parts gui
within tubular and slotted guides substantially as described and shown in
drawings Fig. 1 and Fig. 7.
6. The construction and combination of an arrangement of electro magnets
solenoids actuating a vibratory lever device the axis of which is at right angle
the axis of the brake wheel controlled by it, with suspending means pas
downwards and through tubular guides and so as to be protected thereby as

page_text: 7. The construction and use of a reflecting diaphragm placed above the level of
the arc but close to said level and so formed and hollowed out that it acts the
triple purpose of
a) Of a carbon guide.
b) A stiffener for the side rods.
c) A reflector and economiser of consumption of carbon substantially as and
for the purposes set forth and shown by the drawings.
Dated the 1st day of February 1896.
a) Of a carbon guide.
b) A stiffener for the side rods.
c) A reflector and economiser of consumption of carbon substantially as and
for the purposes set forth and shown by the drawings.
Dated the 1st day of February 1896.
WM. BROOKES & SON,
55 & 56 Chancery Lane, London, Agents for the Applicants.