Improvements in Arc Lamps for Projection and for Laboratory or like Purposes.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Arc Lamps for Projection and for Laboratory or like
Purposes.
We, JOHN STUART, Managing Director of Ross Limited, of 111, New Bond
Street, in the County of London, and JOHN HENRY BARTON, of the same place,
Optical Assistant, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object to improve and simplify the construction of
arc lamps used for projection.
According to this invention a support for the lamp is secured to the foot
piece which is laterally adjustable on the base, or bed plate. This securing is
preferably effected by a joint and binding by means of which the lamp can be
adjusted at any suitable angle or vertically. This support consists of a piece
with guides near the sides to receive a long slider which may be guided also by
screws passed through long slots in the support and screwed into the slider.
The slider is provided with rearward extensions at top and bottom in which is
mounted a double screw (provided with a milled head or other means of turning
it) on the respective portions of which (which are reversely threaded) are carried
the nuts which carry the arms by which the carbon holders are supported. These
arms pass at one side of the support to the front of the lamp and are guided by
a guide on the support. The said arms are provided with insulating material
for insulating the forward parts of the arms from the rearward parts. The
upper carbon holder is made adjustable forward and backward by means of a
guide and screw or other equivalent arrangement by which the part of the arm
carrying the carbon can be adjusted. The slider is moved up and down for
vertical adjustment of the carbons by means of a rack on the slider and a
pinion on a shaft mounted in a bearing carried by the support so that by turning
the pinion in one direction the slider is lowered and by turning it in the other
direction the slider is raised. The line wires are connected to the forward parts
of the arms carrying the carbon holders so that the support and slider and all
parts of the lamp except the forward parts of the arms the carbon holders and
the carbons are insulated from the current.
Dated this 14th day of October 1898
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Arc Lamps for Projection and for Laboratory or like
Purposes.
We, JOHN STUART, Managing Director of Ross Limited, of 111, New Bond
Street, in the County of London, and JOHN HENRY BARTON, of the same place,
Optical Assistant, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
This invention has for its object to improve and simplify the construction of
arc lamps used for projection and for laboratory work or like purposes.
We will describe the invention with reference 'to the accompanying drawings.
Figures 1 and 2 being elevations at opposite sides. Figure 3 a back elevation
(with the lamp in a vertical position) and Figure 4 a horizontal section on the
line 1, 2, Figure 1 (also with the lamp in a vertical position).
According to this invention a support C, for the lamp is secured to the foot-
piece A which is laterally adjustable on the base or bed plate B. The securing
of the support to the footpiece is preferably effected by a joint c and binding
screw c by means of which the lamp can be adjusted at any suitable angle or
vertically. The construction and operation of the centering motion of the lamp
by moving the foot-piece A on the bed-plate B is preferably like that described
in the Specification of Letters Patent No. 30,247 of A.D. 1897. The said sup-
port C consists of a piece with guides c2 near the sides to receive a long slider D
which is secured to the support C, by screws & passed through long slots c³ in the
said support C and screwed in the slider D. The said slider D is provided with
rearward extensions ³ at top and bottom in which is mounted a double
screw E (provided with a milled head e or with other means for turning it) on
the respective portions of which (which are reversely threaded) are carried the
nuts which carry the arms F F by which the carbon holders off are sup-
ported. By rotating this milled head e and consequently the double screw E
the nuts are caused to approach or recede from each other and consequently
the like movement is conveyed to the carbons. These arms F F pass at one
side of the support C, to the front of the lamp and are guided by a guide on
the support C, the arms being each provided with a spring plate screwed to
the rear part of the arm to engage the guide. The said arms FF2 are provided
with insulating material at f³ for insulating the forward parts of the arms from
the rearward parts. The upper carbon holder is made adjustable forward and
backward by means of a guide and screw or other equivalent arrangement by
which the part of the arm carrying the carbon can be adjusted. This is shewn
as being effected by making the rear part of the arm in two portions f* f³ capable
of sliding in guides upon each other and held together by a screw 9 passing
through a slot in the part f and screwed into the part f The part fis
adjusted on the part f by means of a screw / working in the part f and pro-
vided with a collar h² engaging in a recess in the part f4 so that by rotating
the screw in one or other direction the upper carbon can be moved backwards
or forwards for adjustment. The slider D is moved up and down for vertical
adjustment of the carbons by means of a rack on the slider and a pinion i on
a shaft I mounted in a bearing carried by the support C, so that by turning
the pinion in one direction the slider D is lowered and by turning it in the
other direction the said slider is raised. The line wires are connected at 7 and k
to the forward parts of the arms carrying the carbon holders so that the sup-

page_text: port C, and slider D and all parts of the lamp except the forward parts of the
arms the carbon holders and the carbons are insulated from the current.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that
what we claim is :-
1. In arc lamps for projection, laboratory work or the like the combination
with a hinged support and a slider vertically adjustable on the support of arms
for the carbon holders, guided at one side of the support as described, and means
for adjusting the upper carbon holder by backward and forward movement of
one part of the arm upon the other substantially as hereinbefore described.
2. An arc lamp for projection, laboratory work or the like, constructed or
arranged; substantially as herein before described and illustrated in the accom-
panying drawings.
Datal thi 14th 1... £ T1 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.