IMPROVEMENTS IN ELECTRIC-LIGHTING APPARATUS.
Year: 1880

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 ELECTRIC-LIGHTING APPARATUS.". A communication from.
abroad by Hiram Stevens Maxim, of Brooklyn, New York, United States of
America
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 23rd November 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. " IMPROVEMENTS IN ELECTRIC-LIGHTING
APPARATUS." A communication from abroad by Hiram Stevens Maxim, of
Brooklyn, New York, United States of America.
This Invention relates to improvements in electric lamps or lighting apparatus,
and is carried into practice as hereinafter described.
DESCRIPTION OF THE DRAWING,
Figure 1 is a side elevation of a lamp constructed in accordance with my.
Invention.
Figure 2 is a vertical section of the same taken near the centre, and
Figures 3, 4, 5, and 6 are enlarged views of detached parts. Similar letters of
reference indicate like parts in each Figure.
A is a case made of wood or other non-conducting material containing the:
mechanism for regulating the feeding of the carbons; B is a glass cylinder or
enclosing device surrounding the focus, and hereinafter referred to as the globe;
C is a thin flat bar of metal supporting the globe. This bar is so arranged as to
move freely up and down in slots cut in the arms a, a, attached to the case A, and
is supported at any desired position by the dog c.engaging with teeth in its edge..
D is the upper carbon-carrier, and E is the lower carbon-carrier.. The construction
of the clamp holding the lower carbon is best shown in Figure 6.
2.7
:
The two sides d, d¹, are made in separate pieces, and are held together by the.
screw b; at one end they embrace the head of a horizontal pin g attached to the.
D

page_text: lower carbon-carrier, and at the other end bear two semicylindrical jaws e of
suitable size to hold the lower end of the carbon. The carbon and clamp may be
adjusted to any desired position, and fixed by turning the screw b. F is a bar
rigidly attached to the case A. G is a flat bar supporting the lower carbon-carrier.
His a link pivoted to the bar F, and also to the bar G. The form of the link is 5
best shown in Figures 3 and 4. I is a flexible flat strip of metal attached at one
end to the case A, and at the other end to the bar G. J is a lever, which I term
an armature-lever, pivoted to the case A at h, and to the bar G at j by means of the
connecting rod K. L is an axial magnet placed in the lamp-circuit, and M is its
core. The upper end of the core passes through and is firmly attached to the head 1
of an inverted cylindrical box q which fits over the upper head of the helix, and
acts as a dash-pot or controlling chamber for preventing sudden movements of the
regulating mechanism. The end of the lever J works in a recess in the side of
the core M. N is an adjusting screw for limiting the downward movement of the
core M. O is a train of gearing working in a rack P on the side of the upper 1
carbon-carrier, and controlling its downward movement. A detent m upon the
lever J is so arranged as to come. into contact with a star-wheel upon the most
rapidly moving shaft of the gearing when the lever is depressed. Qis a rod passing
through the lower carbon-carrier, and suspended from the case A by means of the
spring R. S is an adjusting nut for regulating the tension of the spring R. T is a
rod attached to the bar G by means of the brackets t, t¹, through which it has a
free movement longitudinally. V is a spiral spring attached to the rod T, and
bearing against the bracket t¹. The rod T has a shoulder x so arranged as to bear
against the case A when it is thrust up by the spring V, and at its lower end passes
through the lower carbon-carrier and terminates in a forked head W, so arranged :
that it may be made to straddle the carbon-carrier, as shown in Figure 5, or when
turned a quarter of a revolution, to stand upon its lower surface. In the former
position the shoulder x bears against the lower surface of the case, and in the
latter it is drawn down away from it.
The lamp is suspended by means of the tubular support Y enclosing the upper
carbon-carrier, and the current is admitted to the upper carbon-carrier through a
binding post, not shown in the Drawings, electrically connected with the spring ✗
and to the lower carbon-carrier through the binding post Z and spring I.
The operation of this lamp is as follows, that is to say:-
The forked head W is drawn down and turned around until its legs stand upon
the lower surface of the carbon-carrier E, when the spring R raises the bar G and
lever J, until the detent m is raised from the escapement-wheel of the gearing O..
The upper carbon-carrier descends by its own weight until the points of the
carbons come into contact, when the circuit is completed, and a strong current
passing excites the coil L, and draws down its core M, at the same time depressing
When the arc
the lower carbon and arresting the descent of the upper carbon.
becomes long, the coil L becomes too weak to overcome the tension of the spring R,
and the lower carbon is gradually raised and the detent m is withdrawn, allowing
the upper carbon to descend until equilibrium is again restored. The length of
the arc may be regulated by adjusting the tension of the spring R, and the lamp
may be stopped at any time by turning the head W, until it straddles the lower
carbon-carrier E, when the spring V obtaining a bearing point against the case A
at the shoulder x, overcomes the tension of the spring R, and keeps the lower
carbon depressed. .:
It will be observed that the weight of the upper or positive carbon has no.
influence upon the operation of the regulating device, which is a material advantage,.
as the negative electrode is consumed only half as rapidly as the positive one.
Where the spring regulating the length of the arc has to support the upper carbon,
as in lamps of the ordinary form, it is frequently necessary to readjust its tension
during the burning of a pencil of considerable length, on account of the diminution,
of its load, but this difficulty is greatly reduced by applying the adjusting device to
the negative carbon. At the same time the arrangement above described secures

page_text: all the advantages of having the regulating mechanism above the focus where it
does not obstruct the light.
The pivoted link H and the flexible strip I hold the bar G in place horizontally
free froin frictional contact with all other parts of the lamp, so that the regulator is
very sensitive to changes in the current, and susceptible of nice adjustment.
It will also be observed that all the supports, both for the lower carbon-carrier
and for the globe, are placed on the same side of the focus, and in a line with each
other, and they are made flat with their edges turned toward the focus, so that they
cast very little shadow, and that only in one direction.
It is obvious also that the globe B may be lowered by raising the dog c without
disturbing the other parts of the lamp. This is a valuable feature of the said lamp,
as it is frequently desirable to remove or replace the globe when carbons of full
length are in position without interfering with their adjustment, and in such lamps
as ordinarily constructed this cannot be conveniently done.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. In an electric lamp or lighting apparatus, a gravitating carrier for the
upper carbon, and a train of gearing controlling its descent, in combination with an
electro-magnet and armature-lever operating a detent engaging with said gearing,
and a carrier for the lower carbon suspended from said lever, substantially as above
described.
Second. In an electric lamp or lighting apparatus, an electro-magnet and
mechanism for controlling the feeding of the upper carbon located above the focus,
in combination with a carrier for the lower carbon, movable vertically and
connected with the armature-lever of said electro-magnet, substantially as herein
described.
Third. In an electric lamp or lighting apparatus, an electro-magnet controlling
the feeding mechanism, in combination with a dash pot or controlling-chamber
fixed to the armature or core of the electro-magnet and surrounding its head,
substantially as above described.
Fourth. In an electric lamp or lighting apparatus, the combination of a lower
carbon-carrier and a globe surrounding the focus with thin flat supports for said
carrier and globe, placed edge to edge upon the same side of the focus, and in the
same vertical plane with it, substantially as above set forth.
Fifth. The carbon-carrier E in combination with the bar G, the link H, and
flexible strip I, substantially as herein described.
Sixth. The carbon-carrier E in combination with the adjustable spring R, the
spring V, rod T, and forked head W, substantially as above described.
Seventh. The side pieces d, d', in combination with the screw b, pin g, and
jaws e, substantially as above described.
Eighth. The combination of the globe B with the support C and dog c, substan-
tially as above specified.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty third day of November, in the year of our
Lord One thousand eight hundred and eighty.
WM. ROBT. LAKE. (L.S.)