Improvements in Electric Arc Lamps.
Year: 1892

page_text: Date of Application, 3rd Sept., 1892
Complete Specification Left, 2nd June, 1893-Accepted, 22nd July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Electric Arc Lamps.
We 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:-
This invention relates to are regulator lamp apparatus and consists of improve-
ments in the Patent taken out by one of us-Rookes Evelyn Bell Crompton-and
the late Tom Crabb of Arc Works Chelmsford, and described in the Specification
of our Letters Patent dated May 22nd 1883 No. 2539. In our present invention
we control the movements of our vibrating lever in respect of the two bare points
described in the aforesaid Specification and therein referred to as indicated by
letters a y, by a pair of solenoids placed side by side symmetrically on either side
of the central vertical line of the lamp. One of these solenoids is series wound in
the main lamp circuit and the other is shunt wound connected across the are in the
usual manner. These solenoids are provided with iron cores which cause the
vibrating motion of the lever and hence control its movements in a more perfect.
manner than was the case in the Specification above referred to.
Among the
advantages are 1st, that it is possible and easy to make all moving parts
symmetrical and balanced as regards their mass to such as extent that any motion
applied to the lamp by an external blow or other cause has no tendency to cause
the parts to change their position due to their momentum. This fact is of great.
importance when lamps have to be used in exposed situations or are subject to a.
sudden shock. Another advantage of the parts being so balanced is that we may
entirely avoid the use of springs and the variations in regulating power which
they entail due either to the varying strength or weakening of these springs by the .
action of heat, corrosion or otherwise.
In carrying out our invention we sometimes prefer to make the series wound
solenoid coil namely that wound in the main circuit, somewhat shorter than the
other and mount on the top of it a dashpot so as to bring it to the same length.
when viewed externally as the shunt solenoid. The piston of this dashpot is
mounted direct on the top of the core and in some cases we place in this piston a
small valve opening upwards as described in the invention of one of us-Rookes.
Evelyn Bell Crompton and John Westbeech Kempster, in our Specification
No. 67 of 4th January 1883 the object of this being to allow of a rapid movement.
of the carbons when approaching one another and a slower movement when they
are being separated.
For double carbon lamps we use the same arrangement of a single pair of
solenoids but the vibrating lever is contrived to be double so as to support a rack-
rod with its escapement mechanism on either side of the centre line of the lamp..
For such double carbon lamps we prefer to support the negative carbon by a single
vertical rod as shown in the first Specification above referred to; for non-focussing
lamps the lower carbons being fixed by the usual holders to a T head provided at the
lower end of this rod, but for focussing lamps we shape this rod in such manner.
that the lower carbons can be mounted or L shaped frames free to slide up and.
down it. For single carbon non-focussing lamps we prefer to carry the lower-
carbon by a pair of side rods carrying a bottom cross head and carbon holder, but
for focussing lamps the lower carbon is mounted on au L shaped frame as in the
double lamp, which is free to slide on one of the slide rods. In both cases the
focussing movement is obtained by the L shaped frames being attached by means.
of a light chain passing over a pulley and then attached to the upper carbon

page_text: In all
holder so that the descent of the latter causes the negative carbon to rise.
cases the negative carbon supports are insulated from the main body of the lamp.
We prefer to make our improved lamps with the framework, the bottom of
which can be turned in a lathe to a cone which can drop into a seating in the lamp
case and be insulated therefrom by a conical packing ring of mica, asbestos or
other suitable material.
To protect these lamps from the weather we prefer to use the following
arrangement. We screw into the conical base ring of the case a pair of vertical
tubes placed symmetrically on either side of it. The top of the cover is made of
cast iron or suitable material and is provided with two light metal rods which can
enter into and are free to slide up and down in these two tubes. The lower ends
of these rods are fitted with spring catches similar to those in the stem of an
umbrella which engage into notches placed close to the top of the two tubes and
are so contrived that by pressing on these catches the metal rods and cover can
be raised, the rods sliding telescopically within the tubes, the catches and their
corresponding, notches are arranged so that the rods can be fixed by them at two
positions, namely right home and nearly out, or the rods can be withdrawn entirely
from the tubes. If we wish to close the lamp, the lamp is closed by a suitable
metal cylinder being slipped over it between the two tubes, the two rods of the
cover are then entered into the tubes and it is; slid down until the notches engage
in the home position a groove in the cover of the disc protecting the upper edge
of the metal cylinder. To re-open it, in order to obtain access to the parts, by
pressing on the catches the cover ring and rods may be raised and. allowed to stand
in the upper, position the cylindrical part of the cover can then be removed. The
cables conveying the current are brought into the lamp through bent tubes situated
in the upper part of the cover plate above described. Instead however of com-
municating directly with the terminals of the lamp they are connected to 2 cylindro-
conoidal spikes mounted on the cable but insulated from the cover. The terminals
proper of the lamp consist of a pair of split tubes which are mounted in such a
position that when the lamp is closed the above spikes. enter into. trumpet mouths
and thus form the connection; the advantages of this arrangement being that the
act of opening the lamp disconnects it from its circuit and thus enables the parts
to be handled without the least danger. Also one lamp can be taken down from
the circuit and another one substituted without disconnecting or cutting away any
joints.
i.
In some cases we make the side rods of the lamps which support the lower
carbon holder in order that rods may slide. telescopically within. them and support
the globe or lantern.
Dated th211
1
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for.the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lamps.
We 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 and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention relates to are regulator lamp apparatus and consists of improve-
ments in the Patent taken out by one of us Rookes Evelyn Bell Crompton and the
late Tom Crabb of Arc Works Chelmsford, and described in the Specification of
their Letters Patent dated May 22nd 1883 No. 2539. In our present invention we
control the movements of our vibrating leyer in respect of the two bare points

page_text: described in the aforesaid Specification and therein referred to as indicated by
letters y, by a pair of solenoids placed side by side symmetrically on either side of
the centre vertical line of the lamp.
One of these solenoids is series wound' in the main lamp circuit and the other' is
shunt wound connected across the arc in the usual manner. These solenoids are
provided with iron cores which cause the vibrating motion of the lever and hence
control its movements in a more perfect manner than was the case in the
Specification above referred to. Among the advantages we claim are first that it
is possible and easy to make all moving parts symmetrical and balanced as regards
their mass to such an extent that any motion applied to the lamp by an external
blow or other cause has no tendency to cause the parts to change their position due
to their momentum. This fact is of great importance when lamps have to be used
in exposed situations or arc subject to a sudden shock. Another advantage of the
parts being so balanced is that we may entirely avoid the use of springs and the
variations in regulating power which they entail due either to the varying strength
or weakening of these springs by the action of heat, corrosion or otherwise.
In carrying out our invention we sometimes prefer to make the series wound
solenoid coil namely that wound in the main circuit, somewhat shorter than the
other and mount on the top of it a dash-pot so as to bring it to the same length
when viewed' externally as the shunt solenoid. The piston of this daslipót is
mounted direct on the top of the core and in some cases we place in this piston a
small valve opening upwards as described in the invention of one of us Rookes
Evelyn Bell Crompton and John Westbeech Kempster, in our Specification No. 67
of 4th January, 1883 the object of this being to allow of a rapid movement of the
carbons when approaching one another and a slower movement when they are
being separated. For double carbon lamps we use the same arrangement of a
single pair of solenoids but the vibrating lever is contrived to be double so as to
support a rack rod with its escapement mechanism on either side of the centre line
of the lamp. For such double carbon lamps we prefer to support the negative
carbon by a single vertical rod as shewn in our Specification above referred to;
for non-focussing lamps the lower carbons being fixed by the usual holders to, a
Thead provided at the lower end of this rod, but for focussing lamps we shape this
rod in such manner that the lower carbons can be mounted on L shaped frames
free to slide up and down it.
a
For single carbon non focussing lamps we prefer to carry the, lower carbon by
pair of side rods' carrying a bottom cross head and carbon holder, but for focussing
lamps the lower carbon is mounted on an L shaped frame as in the double lamp,
which is free to slide on one of the side rods. In both cases the focussing movement
is obtained by the, L shaped frames being attached by means of a light, chain
passing over a pulley and then attached to the upper carbon holder so that the
descent' of the latter' causes the negative carbon to rise. In all cases the negative
carbon supports are insulated from the main body of the lamp. We prefer to
make our improved lamps with the framework, the bottom of which can be turned
in a lathe to a cone which can drop into a seating in the lamp case and be
insulated therefrom" by a conical' packing' ring of mica asbestos or other suitable
materiál
"
"
To protect these lamps from the weather we prefer to use the following
arrangement. We screw into the conical base ring of the case a pair of vertical
tubes placed symmetrically on either side of it. The top of the cover is made of
cast iron or suitable material 'and is provided with two light metal rods which can
enter into and are free to slide up and down in these two tubes. The lower ends
of these rods are fitted with spring catches similar to those in the stem of an
umbrella which engage into notches placed close to the top of the two tubes and
are so contrived that by pressing on these catches the metal rods and cover can be
raised the rods sliding telescopically within the tubes, the catches and their
corresponding notches are arranged so that the rods can be fixed. by them at two
positions, namely right home and nearly out, or the rods can be withdrawn entirely

page_text: Figure 2 indicates a section taken at right angles to Fig. 1.
Figure 3 is a detail of parts drawn to an enlarged scale.
Figures 4 and 5 indicate two forms of valves that may be used to control the
inlet to the dashpot.
The improved lamp consists essentially of two solenoids A and B of which A is
in series with the main current, and B in shunt across the arc. These solenoids
actuate the two iron cores C and D, which in their turn rock the lever E, E¹ about
its middle joint E' at which it is pivotted to the frame E3 E³.
This lever E E' controls the escapement which consists of a brake wheel b sleeve F
and rack rod G substantially as in the Specification of Patent No. 2539 of 1883
already referred to.
The core C is fitted with a plunger C at its upper end and moves in the
dashpot C².
:
This plunger or piston C₁ is provided with a light valve C³ the effect of the
intervention of which is to allow the carbons to come together rapidly, but to be
drawn apart slowly.
To the frame E³ E³ but insulated from it, aré fastened the two guide rods K K'
on which slides the shaped negative carbon bracket K
This is connected to the rack rod G by a light chain 61 or flexible connection
passing over the pulley G2 as shewn in Fig. 2 and is thus raised by the descent of
the rack rod G. This action of these parts coupled with a proper selection of
suitable carbons renders the lamp substantially exactly focussing.
The double carbon lamp is operated in exactly the same manner as that
previously described for a single lamp as far as the principal of arrangement is
concerned,
Fig. 6 is a sectional side view of a double carbon lamp and
Fig. 7 indicates a section taken at right angles to Fig. 6.
The details shown on Figures 3, 4 and 5 and the previous description of these
details applies also to the double lamp. It will be seen that the double lamp
differs from the single lamp only in that the lever E E' is made wider when seen in
plan view so that it can carry two rack rods with their respective brake wheels and

page_text: sleeves, the arrangement of the regulating solenoids being the same as in the single.
lamp.
In place of the guide rods K and K of the single lamp, in this case we use one.
centre guide rod K which may be formed of H or other convenient section so that.
the two lower carbon holders K' can slide past one another without interference.
This is clearly shown in Fig. 7. Both the single and double lamps as above
described are fitted to their cases c but insulated therefrom by a ring seating of
asbestos, or other suitable material shown at a.
is a cast iron base into which are screwed two tubes N N'.
N2 is a cast iron cover, into which are screwed two rods M and M' which slide
in the, said tubes N,N'.
The lower ends of these rods are fitted with catches n (like those of an
umbrella) which engage in notches n' at either pair of points or may be drawn out
altogether.
Now suppose it is desired to close the lamp a plain zinc cylinder is slipped over-
it and between the rods N N¹.
The base is then pushed upwards, till the cover N2 comes against the top of
this cylinder at which point the catches are arranged to engage with the lower ends.
of the tubes.
To open the lamp the base k is grasped by both hands the catches n pushed back
with the thumbs, and the lamp lowered to the position shown in the Fig. 1 by
dotted lines where the catches n will hold it (whilst it is being cleaned).
On pressing the catches n again when in this position, the lamp is once more.
released and may be entirely withdrawn.
The cable is brought into the lamp in the usual way through bent tubes d in the
cover N'
Instead however of communicating immediately with the terminals of the lamp
the cable is fastened into a metal spike L mounted on an insulating bracket L.
On closing the lamp in the manner described, this spike L fits into a split tube L²
which forms one of the terminals.
There are of course two spikes, cables, terminals and other parts, one set positive
and the other negative.
The advantages of this arrangement of mechanism are that the act of opening
the lamp disconnects it from circuit, and enables one to handle it without the least.
danger.
Also that the lamp can be taken down from the pole and another one substituted
without disconnecting or cutting away joints; as must be done with lamps.
commonly used.
The parts of these lamps are arranged to balance one another so as to render
them unaffected by shocks and enable them to burn steadily on board ship or in
similar places.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what.
we claim is :-
1. The arrangement or combination of parts forming improvements in electric.
are lamps constructed on the principle described in the Specification of Rookes
Evelyn Bell Crompton and Tom Crabb's Patent No. 2539 of 1883 whereby the
act of removing the lamp from its holding parts causes disconnection of it from
circuit and consequent discontinuance of current through it thereby enabling it to
be manipulated with safety also that the lamp may be removed from its supports.
and replaced or another substituted therefor without necessitating any discon-
nection or cutting of joints or the like substantially as set forth and shown by the
drawing.
2. The arrangement or combination and use in electric arc lamps of the type
described, of a vibrating lever co-operating with solenoid devices having iron cores
which cause the vibrating motion of the lever and control its movements so that all

page_text: the moving parts can readily be made symmetrical and balanced as regards their
mass to such an extent that any motion imparted to the lamp by an external blow
or other cause will have no tendency to cause the operative parts to change their
position owing to such momentum at the same time avoiding the use of springs
all substantially as and for the purpose hereinbefore set forth and shewn in the
drawings.
3. The arrangement or combination of parts in an electric arc lamp of the type
described forming the double lamp substantially as herein described and shown on
Figures 6 and 7.
4. In an electric arc lamp the combination or arrangement of parts for con-
trolling and regulating the movements relatively of the carbons for maintaining
the arc substantially as and for the purpose set forth.
5. In an electric arc lamp the arrangement of insulating ring a substantially as
described and shown in Figures 1, 2, 6 and 7 as and for the purpose set forth.
Dated the 1st day of June 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicants.