Camp Projection and poses.
Year: 1897

page_text: Camp Projection and poses.
GEORGE DAVENPORT, 19, John Street, Strand, London, W.C., Clerk, do
hereby declare the nature of this invention to be as follows:-
This invention consists of an arrangement or combination of parts for holding,
adjusting, and feeding together or separating, mechanically, by hand, the carbons
of an electric arc lamp, in such a way that they shall approach each other at about
the same rate as that of the consumption of the carbons.
This I accomplish by fixing rackwork to two flat or rectangular metal bars, to
one end of each of which is attached, at right angles, an arm with a carbon holder.
The other ends of the bars pass through guides in a metal box attached to a standard
or upright support which, by means of a joint, is capable of inclination. Into the
box a rod is inserted carrying two pinions of unequal diameter which gear into the
racks of the bars. This rod ends in a milled head wheel, the turning of which
enables the racked bars to be worked, and so causes the carbons to approach each
other or recede at a pre-arranged rate, (say one and a half to one), the diameter of
the carbons employed being so selected that the rate of feeding together of the
carbons is approximately equal to their consumption, and the position of the arc
is thus maintained at as nearly as possible the same centre during the time the
lamp is in use. A rackwork adjustment is also provided for moving the top arm
and carbon holder backwards or forwards so that the position of the top carbon may
be adjusted relative to the lower carbon.
Other adjustments for moving the arc lamp vertically on the pillar or standard
are provided, as well as rotary or lateral adjustments, so that, when used for optical
projections, a definite centre can be obtained and preserved at any time by a slight
adjustment of these rackwork or other movements.
Dated this 12th day of August 1897
An Improved Electric Arc Lamp for Projection and other Purposes.
GEORGE DAVENPORT, 19, John Street, Strand, London, W.C., Clerk, do hereby
declare the nature of this invention and in what manner the same is to be per-
[Price 8d.1

page_text: formed, to be particularly described and ascertained in and by the following
statement:—
This invention consists of an arrangement of parts for holding, adjusting, and
feeding together or separating, mechanically, by hand, the carbons of an electric
arc lamp, as described below, and illustrated by the accompanying drawing.
Two Hat or rectangular metal bars, A, and B, carry the arms, C and D, of the
carbon holders, H and J.
These bars are arranged to slide opposite each other in a metal box, E, which is
fitted with guide pieces, F and G, on the upper and lower ends of the box.
Other arrangements of guides may be employed if desired.
A toothed rack is attached, longitudinally, along the inner face of each of the
bars, A and B, and a rod, carrying two pinions of unequal diameter, and working
in bearings on the top of the box, E, or other suitable position, is arranged so that
each pinion gears into one of the racks. On turning the pinions by means of the
rod, I, the bars, A and B, are raised or lowered at dissimilar rates, in opposite
directions, at the same time.
The proportions between racks and pinions are preferably arranged so that the
upper bar, B, is moved at one and a half times the rate of the lower bar, A, though
other proportions may be employed, and the sizes of the carbons are so proportioned
that the rate of feeding of the two bars is approximately equal to the rate of the
consumption of the carbons. By this means the burning points of the carbons are
maintained at approximately the same centre during the time the lamp is in use.
The carbon holders, H and J, consist of a form of vice, the jaws of which are
adjustable by a pair of parallel screws, so that they will hold various sizes of
carbons and permit of lateral adjustment of such carbons.
The arm, C, carrying the carbon holder, H, is connected to the lower end of the
bar, A, by screws or other suitable means, but is insulated from the bar by vul-
canized fibre, mica, or other insulating substance. The upper end of the bar, B, is
provided with a guide box in which the arm, D, carrying the carbon holder, J,
works. Along the upper side of the arm, D, a toothed rack is fixed. A rod, work-
ing in bearings at the upper part of the guide box, carries a pinion which gears in
this rack so that, by the turning of the milled head, K, of the rod carrying the
pinion, the arm D), is moved backwards or forwards so as to allow of adjustment of
the upper carbon relative to the lower one.
Instead of the rack and pinion movement the arm, D, can be shifted backwards
or forwards by a sliding adjustment and fixed at the desired position by a clamp-
ing screw.
The metal box, E, containing the above combination of parts, is supported on an
adjustable stand.
This stand consists of the tube, L, which is attached by a foot to a base plate, M,
but is preferably insulated from it. In the tube, L, a tube, N, slides. This tube
has a toothed rack fixed to it along part of its length, which slides in a slot cut in
the tube, L. The tube, N, is raised or lowered by means of a rod and pinion, O,
working in bearings attached to the tube, L. In the tube, N, is another tube, P,
which is capable of rotation in the tube, N, and which can be fixed in position by
the clamping screw, Q.
The tube, P, is provided with a head piece to which the box, E, by means of an
arm or projecting piece at its back, can be attached and clamped vertically or at
an angle by the screw, R.
The arrangement of parts described above forms an electric arc lamp, worked by
hand, having a combination of movements by means of which the carbons can be
fed together or separated, directly, by the turning of one rod, at rates proportional
to the relative sizes of racks and pinions, the carbons themselves adjusted relative
to each other, the angle of the lamp and carbons varied, and the lamp raised,
lowered, or rotated, as described.

page_text: Having
110 W
particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:
110 W
Having particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
CLAIM.
The arrangement and combination of parts, substantially as described above, for
1.
particularly described and ascertamed the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
CLAIM.
The arrangement and combination of parts, substantially as described above, for
holding, adjusting, centring, and feeding together or separating, mechanically, by
hand, the carbons of an electric arc lamp.