IMPROVEMENTS IN ARC ELECTRIC LAMPS
Year: 1882

page_text: LETTERS PATENT to Alfred James Jarman, of 10, Glenarm Road, Hackney,
London, E., Electrician, for an Invention of "IMPROVEMENTS IN ARC
ELECTRIC LAMPS."
PROVISIONAL SPECIFICATION left by the said Alfred James Jarman at the
Office of the Commissioners of Patents on the 6th February 1882.
ALFRED JAMES JARMAN, of 10, Glenarm Road, Hackney, London, E., Electrician.
"IMPROVEMENTS IN ARC ELECTRIC LAMPS."
My Invention relates to improvements in arc electric lamps. A solenoid or
electro magnet is mounted in such a manner as to be adjustable with regard to its
core or armature, so that the desired amount of attraction may be obtained in
either the coro or armature for the current flowing round the coil or coils. The coro
or armature is provided with lugs carrying pins or rollers, upon which slide cross-
bars pinned at their centres or crossing points, the opposite ends of these cross bars
resting when no current passes through the lamp upon a bedplate which keeps thein
extended like the letter X, and causes the reverso end to that resting upon the
bedplate to press upon the pins or rollers fixed in the lugs of the core or armature
above referred to. Near the bedplate end the crossbars are pivoted to two clutch
blocks or gripping pieces accurately fitted, so as to e brace the rod carrying the
upper or positive carbon, which when no current pas rests upon the lower or
negative one and completes the circuit. Upon a current flowing through the coil
or coils of the solenoid or electro magnet, the core or armature is drawn into or
towards it, first causing the cross arms to straighten and force the clutch or
gripping picces against the rod carrying the upper carbon, and then lifting it and
establishing the arc. By means of the crossbars a perfectly parallel motion is
imparted to the clutch pieces, so that they grip the rod firmly compelling it to
obey the use of the core or armature. The slightest decrease in the magnetization
of the core or armature causes the cross arms to extend, releasing the rod and
shortening the arc. I provide a shunt arrangement whereby the lamp is cut out
of circuit should it fail, and also means for regulating the arc to any strength of
current. By reversing the position of the solenoid or electro magnet with its core
or armature, the arrangement is applicable to a lamp working as a shunt.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred James Jarman in the Great Seal Patent Office on tho
6th May 1882.
ALFRED JAMES JARMAN, 10, Glenarm Road, Hackney, London, E., Electrician.
"IMPROVEMENTS IN ARC ELECTRIC LAMPS."
My Invention relates to improvements in arc electric lamps. A solenoid or
electro magnet is mounted in such a manner as to be adjustable with regard to its
core or armature, so that the desired amount of attractive influence may be exerted
upon the sliding core or arinature for the current flowing round the coil or coils of
the solenoid or electro magnet. The base of the core or armature is provided with
lugs carrying pins, or rollers may be substituted for pins upon which slide or rub
crossbars pinned at their centres or crossing points, the opposite ends of these
crossbars to that bearing upon the pins or rollers before mentioned resting when no
current passes through the lamp upon a bedplate, which keeps them extended like
the letter X, the upper or reverse end to that resting upon the bedplate being
forced against the pius or rollers fixed in the lugs aforo mentioned. The crossbars
near their bedplate end are pivoted to two clutch blocks or gripping pieces,
accurately fitted so as to embrace the rod carrying the upper or positive carbon,
which it will be seen passes through the solenoid and sliding core, and when no
current passes rests upon the lower or negative one and completes the circuit. The
clutch block having considerable surface embraces the rod firmly, and all scoring or
indentation of the rod is obviated. Upon a current flowing through the coil or
coils of the electro magnet or solenoid, the core or armaturo is drawn towards
or into it, first causing the cross arms to straighten and force the clutch or gripping
picces against the rod carrying the upper carbon, and then lifting it and
establishing the arc. By means of the cross bars a parallel motion is imparted
to the clutch pieces so that they grip the rod firmly, compelling it to obey the rise
of the core or armature. The slightest decrease in the inagnetization of the core or
armature causes the cross arms to touch the bedplate, extending them, releasing
the rod, and shortening the arc. I provide a shunt arrangement whereby the lamp
is cut out of circuit should the resistance of the are become too great from any
cause. I also provide means for regulating the length of the are and adjusting the
lamp to the amount of current passing. By reversing the position of the solenoid
or electro magnet with its core or armature, the arrangement is applicable to a
lamp working as a shunt.
Having now generally described my Invention, I will proceed to do so more
particularly by means of the Drawing. Fig. 1 and Fig. 2 represent front and side
views of my improvements in are electric lamps; A is the solenoid which may be
replaced by an electro magnet, as shewn in Fig. 6, to which reference will be made
hereafter; B, B', are two side pillars or standards screwed or otherwise fastened
into a wood or other suitable base. At their upper ends they are screwed to
receive the brass plate or strip O carrying the solenoid A to which it is fastened in
any suitable manner, the plate C carrying the solenoid being adjustable by
means of the locknuts y, y; D is the sliding or sucking core or armature; E, E', are
the two lugs carrying the pins or rollers F, F¹, against which rest the crossbars,
their opposite ends resting upon the bedplate G; near the bedplate end of the
crossbars will be seen the clutch or gripping picces H, H', which are pinned or
otherwise fastened to the crossbars, and are pressed together by the spring I
attached to the pins in crossbars and clutch blocks; Fig. 4 shews a plan or top
view of these clutch blocks with the spring I. Upon the pillars B, B', will be seen

page_text: two small blocks carrying springs J, J, which press upon the armature or sucking
core and force it down. In the plato forming the base of the core or armature is a
screw K, which regulates the travel of the core or armature. Upon a current from
a battery or other suitable source of clectricity flowing round the coil or coils of
wire surrounding the solenoid or electro magnet, the coro D is drawn up, over-
coming the resistance of the springs J, J, and causing the crossbars to force the
clutch pieces H, H', against the rod L, which it will be seen carries the upper or
positive carbon and then lift it, establishing the arc, the length of which can be
regulated by lowering the solenoid A by means of the set screws Y, Y,
upon the
pillars B, B, and by turning the screw K so that the rise of the armature or
sucking core D is kept within desired limits. The current is led into the lamp by
the two binding screws M, M', flowing from the terminal M' round the coil to the
blocks N, which are adjusted by the screw O to exert such pressure against the
rod L as shall prevent its too sudden descent when the current ceases, and also to
ensure good electrical contact with the rod L, thence the current flows through tho
are and bottom carbon to the post P and so out to the terminal M; Fig. 5 shews
a sectional view of the solenoid A. In the sido view, Fig. 2, part of the rod B¹ is
removed, and also the screw K that the spring J and side view of the cross arms
may be clearly seen.
I have hitherto described my lamp for working singly only when under ordinary
working conditions, no governing or regulating means beyond that shewn in Fig. 1
and Fig. 2 is needed; when howover two or more lamps are required to work in
series, it is necessary that each lamp should be controlled and regulated inde-
pendently, or great irregularity in working results. To effect this I use a novel
shunt coil or regulator, which is shewn in Figure 3. As before, A represents the
solenoid or electro magnet O, the plato or strip to which it is fastened to the left
of A will be seen in section, a small solenoid of peculiar construction. It is wound
to a high resistance and forms a shunt to the leading wires of the lamp, sec E, E', 80
that a proportion of the current is always flowing round its coils, a very small
amount however to that flowing through the arc when its resistance is normal.
When however the resistance of the arc is from any cause increased, sufficient
current flows through the fine wire of the coil to overcome the resistance of the
spiral spring, shewn in the interior of the solenoid, by which the shunt coil is
regulated; tho contact bar F is pulled down and the current diverted through the
independent coil K, which attracts the flattened or disc shaped end O of the core P,
the contact bar F is thus held firmly against the insulated contact piece J, and so
short circuits the lamp by the wire Ĺ which it will be seen proceeds directly to tho
terminal M; the core or plunger is slotted through its centre in order to allow
the contact bar F to pass through.
Fig. 6 shews ny lamp worked by an electro magnet, the armature being
adjusted by means of the set screws A, A, and springs B, B, for the current flowing.
Fig. 7 shews the position of the solenoid reversed, the spring forcing the bottom
carbon against the upper or positive one when no current passes where the current
is allowed to flow, the cross arms force the clutch pieces against the rod, drawing
down the rod and establishing the arc.
Having now particularly described my Invention, I would have it understood
that I do not confine myself to the precise details shewn aud described in the
Drawings, as they may be varied or modified in many ways without departing
from the main features of my Invention, but what I consider as novel and original,
and therefore claim as secured to me by these Letters Patent is,-
Firstly. A solenoid or electro magnet fitted with a sucking core or an armature
mounted in such a manner as to be adjustable for the amount of current passing
round the coils, substantially as shewn and described.
Secondly. The crossbar and clutch block arrangement attached to the sucking
core or electro magnet in such a manner as to firmly grip the rod in a parallel grip
when the core or armature is attracted.
Thirdly. The arrangement of pins, lugs, and rollers attached to or forming part

page_text: of the core of the solenoid, or part of the armature of the electro magnet, as shewn
and described.
Fourthly. The gripping blocks or pieces for conveying the current to the upper
carbon with a spring or set screw clamp for controlling tho descent of the rod.
Fifthly. The shunt arrangement consisting of an independent solenoid and
electro-magnet, or two independent solenoids, together with contact bar, sucking
core, and adjustment, substantially as shewn and described.
In witness whereof, I, the said Alfred James Jarman, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One
thousand eight hundred and eighty two.
Witness,
FRANCIS M. ROGERS,
Engineer,
21, Finsbury Pavt.,
E.C.
ALFRED JAMES JARMAN. (L.S.)