Year: 1895

page_text: Date of Application, 19th Mar., 1895-Accepted, 27th Apr., 1895
I, GEORGE ROBERT MACINTIRE, of No. 413 West 25th Street, in the City of
New York, and County and State of New York, United States of America.
Mechanical 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 :-
Arc lamps, as ordinarily constructed, are open to various objections. By reason
of the complicated mechanism which has been thought to be necessary for feeding
or regulating the feed of the carbons they are not only heavy but require consider-
able space, so that for many locations, particularly where the ceiling is low, they
are not available. Moreover the frame-work which supports the carbons and the
feeding mechanism is commonly so constructed as to intercept the rays of light from
the arc at different points. Still again the feeding mechanism is usually so
arranged that the carbon is fed by gravity or a spring under the control of
regulating mechanism, in which case the corrosion of oxidation of the moving parts
not infrequently prevents the proper feed of the carbon. The object which was
primarily in view in this invention was the production of an arc lamp which should
be exceedingly compact and therefore available for use more generally than the
are lamps heretofore constructed. At the same time in making the lamp compact
it has also been made of less weight than other lamps and it has been possible to
reduce very much the area of obstructive parts and to dispense altogether with
some portions of the supporting frame-work which have heretofore been considered
necessary. At the same time the strength and durability of the structure have
not been decreased but on the contrary have been increased. A further object has
been to so arrange the feeding mechanism that it shall act positively and at the
same time shall permit the carbons to be advanced by gravity or by spring
pressure. Incidentally to these main objects various other features of improvement
have been devised all of which will be fully described hereinafter.
In the accompanying drawings:
Figure 1 is a side elevation of a lamp embodying the several improvements
herein referred to, the casing about the feeding mechanism being shown in section,
the globe holder being represented as broken out, a globe being shown in part and
some other parts being broken out to save space :
Figure 2 is a horizontal section. on the line - of Figure 1:
Figure 3 is a detail view in vertical section on the line y-y of Figure 2, with a
portion of the series coil and its jacket broken out :
Figure 4 is a detail view in horizontal section on the line - of Figure 1:
Figure 5 is a detail view in elevation of a portion of the feeding mechanism:
The feeding mechanism and other parts of the lamp are supported upon or by a
plate A which has cast with it or otherwise formed upon it an enclosed casing A'
which projects above the upper surface of the plate, being open beneath. A
stud A is secured or attached to the top of this casing to receive a hook A³ by
which the lamp may be suspended. Upon the plate A are secured the various
parts of the feed controlling mechanism, hereinafter more particularly referred to,
and these are covered and protected by a shell B. The mechanism referred to is
thus completely enclosed and guarded from access of dust or moisture. To the
under side of the plate A, and insulated therefrom, is secured a rod or post C upon

page_text: which is mounted the globe-holding ring D by means of an arm d and sleeve d',
the ring D encompassing the rod C. A second but shorter rod or post C¹ is also
secured to the under side of the plate A, being insulated therefrom, and is adapted
to receive a sleeve d' which is attached to the globe-holding ring D, a latch C' being
secured to said post C¹ and adapted to engage the sleeve d² to maintain the globe-
holder in its normal and elevated position. The globe E may be secured to the
ring D by set-screws c, c, or any other suitable means. When the sleeve d² is
released from the post C¹ the globe may be lowered below the extremity of the
lower carbon holder until the sleeve d¹ rests upon a shoulder c¹ on the post C,
when the globe-holder can be swung to one side to permit it to be cleaned or the
carbons to be attended to and yet will not be disconnected from the lamp. The
lower carbon holder F is also supported by the rod or post C through an arm F.
To the plate A is also secured radially in line with the rod C a sleeve or tube G
which has a slot extending from end to end. The lower end of the sleeve is
steadied by the arm F¹, but is insulated therefrom. Within this sleeve or tube is
mounted a shaft H having a shallow spiral groove h, of steep pitch, formed thereon.
This shaft finds a bearing for its lower end in the cap G' which closes the lower
end of the sleeve G, and extends through the plate A and for a short distance
above it. Upon the shaft H is mounted a travelling nut H¹ which is formed of a
sheet of metal embracing the shaft and having its edges brought together to form
an arm or web h¹ which projects through the slot g and connects the nut, by means of
screws ², with a carriage I which encircles and is guided by the sleeve G and
supports, through an arm i, the upper carbon holder J. The pitch of the spiral
groove h of the shaft H is such that the shaft might be rotated by the weight of
the driving nut and carriage and therefore the action of gravity would effect the
movement of the upper carbon toward the lower carbon. The carriage I is also
constructed in such a manner as to prevent interference with its free descent by
binding upon the tube or shaft and to prevent any movement of the upper carbon
out of line with the lower carbon, being in effect a long sleeve embracing the tube
and having a steady pin which engages a groove g' formed in the tube G opposite
the slot g to guide and steady the carriage and prevent oscillation thereof on the
tube. In this manner the carriage can be made to balance itself as nearly as
possible without causing any binding on either tube or shaft while at the same time
the alignment of the carbons is maintained, the weight of the lamp reduced and
the cost of construction diminished. As suggested herein before, however, the
action of gravity is not alone relied upon but means are provided for effecting the
positive rotation of the shaft. For this purpose the shaft has fixed upon its upper
end a fine toothed ratchet wheel K which is adapted to be engaged and actuated
by a spring-pressed pawl m carried by a sliding bar M which is pressed backward
by a spring m' and forward by the armature M' of the shunt magnet M², the
armature being pivoted as at m² to an extension m³ from the core of the magnet.
The shunt wire is connected to the main line at any convenient point and thence to
a back contact m* carried by an insulated post m³. An insulated contact point m
is carried by the armature M' in position to complete the circuit from the back
contact m and is connected to the coils of the shunt magnet M². From thence
connection is made to the other side of the main circuit.
A forked lever N, which is pivoted upon a suitable supporting post, embraces
the shaft H just below the ratchet wheel K and at its other end is connected to
the armature N' of the series magnet N2, the latter being preferably of the variety
known commonly as the iron-clad, the coils 'being enclosed by a jacket n² which is
connected to the core of the magnet. By means of the lever N the shaft H is
lifted bodily when the current is completed through the series magnet and the
carbons are thereby separated sufficiently for the formation of the arc.
A short shaft is mounted in a suitable bearing supported by the plate A,
being provided at its lower end, below the plate A, with a thumb-piece O¹ and at
its upper end with an arm O2 having a tooth 03. The shaft is acted upon by a
spring O to hold the tooth 03 in engagement with the ratchet wheel K and thus

page_text: to constitute a hold-pawl to prevent backward movement of said ratchet-wheel..
By a partial rotation of the shaft O, by means of the thumb-piece O¹, the
tooth 03 may be made to engage the pawl m and disengage the same from the
ratchet-wheel to permit the free rotation of the shaft H when the carriage I is.
raised by hand.
The connection of the main line to the series coil might be made in any
convenient manner but I prefer to establish such connection through a resistance
coil of peculiar construction which is supported within the upper end of the shell B.
upon a plate or diaphragm B'. This resistance coil P is formed by crimping a
wire, as indicated at p, the crimps lying in the same plane to constitute a ribbon.
which is subsequently coiled spirally about the axis parallel with the plane of the
ribbon with insulating material pl between the convolutions. This arrangement
gives a great extent of resistance wire in an extremely compact and convenient
shape.
From the resistance coil P connection is established to the sleeve G and thence
to the carriage I and upper carbon holder J. From the lower carbon holder
connection is made to the rod C to which the out-going leg of the circuit may be
connected.
The operation of the lamp herein described is in general the same as that of
other lamps of like character and need not be set forth in detail herein. It will
be observed that there is but one supporting rod C in line with the arc and that
the sleeve G stands in the same plane with the carbons and said rod, whereby
there is but a single lateral obstruction for the rays of light. Moreover there is
no cap or other metal piece of large area below the light to cut off any considerable
number of the rays of light. It will be observed also that the carriage I and
arm i with the upper carbon holder J may be raised above the plate A by reason
of the casing A with the open bottom, and a longer carbon thus be used than
would otherwise be possible.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is.
1. In an electric lamp, the combination of a supporting plate, carbon holders
supported by said plate, a single long rod secured to said plate, a globe-holder
and a latch whereby the holder may be secured to said plate, and an arm secured
to said globe-holder and having a sleeve to encircle said single rod, whereby the
globe-holder may be released from the plate and lowered upon the long rod and
swung laterally thereon, substantially as shown and described.
2. In an electric lamp, the combination of a supporting plate, a single rod
depending from said plate, an arm at the lower end of said rod, a carbon holder
supported by said arm, a slotted tube fixed to said plate radially in line with said
rod and to said arm but insulated from the latter, a shaft mounted within said
tube and having a spiral groove of steep pitch, means to rotate said shaft, a
travelling nut mounted on said shaft, a long, sleeve-like carriage mounted on said
tube and connected with said nut, said carriage and tube being formed for
engagement in a line opposite the slot to guide and steady the carriage and prevent
oscillation thereof on the tube, a carbon holder fixed to said carriage and
supported wholly thereby, and independent electrical connections to said rod and
tube, substantially as shown and described.
3. In an electric lamp, the combination of a supporting plate, a rod depending
from said plate and supporting a carbon holder, a slotted tube also depending from
said plate, a shaft mounted within said tube and having a spiral groove, means
supported by said plate to rotate said shaft, a sheet of metal embracing said shaft
to form a nut and having its edges brought together to form an arm projecting
through the slot in the tube, a carriage encircling said tube and connected to said
arm, and a carbon holder fixed to said carriage, substantially as shown and
described.

page_text: a
4. In an electric lamp, the combination of a supporting plate, a shaft having
spiral groove supported by said plate, a travelling nut mounted on said shaft, a
carbon holder connected to said nut, a ratchet wheel fixed to said shaft, a pawl and
means to actuate the same, a short shaft supported by said plate and having an
arm with a tooth to engage said ratchet wheel as a hold pawl and also to disengage
the actuating pawl from said wheel, substantially as shown and described.
5. In an electric lamp, the combination of a supporting plate, having a casing
extending upwardly with an open bottom, carbon feeding mechanism mounted on
said plate around said casing, a shell enclosing said mechanism, a carbon holder, a
carriage therefor, a guide for said carriage fixed to the top of said casing,
whereby the carriage and holder may enter within said casing, and intermediate
means to impart motion from said feeding mechanism to said carriage, substantially
as shown and described.
Dated the 18th day of March 1895.
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.