Improvements in Electric Lighting Appliances for Photographic and other Purposes.
Year: 1890

page_text: Date of Application, 24th Nov., 1890
Complete Specification Left, 24th Aug., 1891-Accepted, 3rd Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electric Lighting Appliances for Photographic and
other Purposes.
I FRANCIS LAUDER MUIRHEAD, of No. 3 Elm Court, Temple, E.C. in the
City of London, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in appliances used in photographing by
means of the electric light and for other purposes. It consists of a parabolical or
other suitable reflector made of thin metal, papier, maché, or other suitable material
coated internally with some white pigment or the reflector may be made of white
paper strained on a light framework. The reflector is fitted with a system of cords
and pulleys to enable it to be raised and lowered and also to be tilted backwards
and forwards.
The electric lamp I use in connection with the reflector consists of two arms
shaped like a pair of tongs and pivotted at the centre of the reflector at the back;
the two longer branches project through the reflector and carry the carbon holders.
The longer branches are of sufficient length to enable the arc of the electric lamp
to be in or near the focus of the reflector. The shorter branches of the lamp
project behind the reflector and are kept apart by means of a right and left handed
screw carried by a rigid attachment to the reflector. In the case when continuous
current is used one thread of the above mentioned right and left handed screw is
made double the pitch of the other so that on turning the screw one arm moves
through double the arc of the other. When the current used is alternating the
pitch of the thread is the same in both screws and the arms feed the carbons at
equal rates.
N
mbo 1900
A. F. SPOONER,
9, Warwick Court, High Holborn, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electric Lighting Appliances for Photographic and
other Purposes.
I, FRANCIS LAUDER MOIRHEAD, of No. 3 Elm Court, Temple, E.C. in the
City of London, 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 :-
My invention relates to improvements in appliances used in photographing by
means of the electric light and for other purposes. It consists of a parabolical or
other suitable reflector made of thin metal, papier maché or other suitable material
coated internally with some white pigment or the reflector may be made of white
paper strained on a light framework. The reflector is fitted with a system of cords
and pulleys to enable it to be raised and lowered and also to be tilted backwards
and forwards.
The electric lamp I use in connection with the reflector is illustrated in the
annexed drawing. It consists of two arms, a, and, b, pivotted at the point, c, at
the back of the reflector in its centre line. These two arms are kept apart by
a right and left handed screw, d, carried in the jaws, e, of a rigid attachment, f, to
the reflector and threading through attachments at the extremities of the two
arms, a, and, b, which are slotted so as to allow the screw to work vertically while
the arms describe the arc of a circle. The pivotted ends of the arms are provided

page_text: respectively with extensions, g, and, . Two longer arms, i, and, k, preferably
tubular in form, fix on to the extensions, g, and, h, and are for the purpose of
carrying the carbon-holders. These are shown broken in the annexed drawing but
in carrying out iny invention they are of sufficient length to enable the arc of the
lamp to be in or near the focus of the reflector. The insulated electric conductors
are preferably carried along inside the tubes, i, and, k, for the greater portion of
their length making connection with the carbons by means of the collars, 1, insulated
by a layer of mica or other suitable substance, m, and insulating washers around
'the screws, n. The carbon-holders are pivotted at, p, and, r, gravitation being
*sufficient to maintain the upper one in a vertical position and the lower one being
kept vertical by' the counterweight,...
It will be seen that upon the screw, d, being turned the carbons will feed. When
a continuous current is employed one thread of the screw is made double the pitch
of the other so that on turning it one arm moves through double the arc of the
other. When the current is an alternating one.the pitch of the thread is the same
in both portions of the screw and the arms feed the carbons at an equal rate.
.
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
The arrangement and combination of parts constituting my improvements in
electric lighting appliances for photographic and other purposes substantially as
hereinbefore described.
A. F. SPOONER,
124, Chancery Lane, W.C., Agent for the Applicant.