A Lamp for Projection and others.
Year: 1896

page_text: Date of Application, 28th Dec., 1896-Accepted, 20th Feb., 1897
A Lamp for Projection and others.
1, BENJAMIN JOSEPH BARNARD MILLS, of 23 Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from Léo Boulade, Antonin Boulade and Francisque
Pascal, all of 8 Place des Jacobins, Lyons, in the Republic of France, Mechanical
Opticians) and in what mauner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The new arrangement of are lamp forming the subject of the present application
is applicable in all cases where it is required to obtain a luminous point capable of
easy regulation and remaining substantially fixed notwithstanding the wear of the
carbons.
It has for its object to facilitate the regulation and replacing of the carbons by
placing at a distance from the arc, and from the parts of the apparatus which may
become heated, all the operating and fixing parts.
The accompanying drawing represents this arrangement, in which
Fig. 1 is an elevation, Fig. 2 a back view of the support, and Fig. 3 a plan of
the saine.
The carbons C C' are carried by two arms B B crossing each other lengthwise
and jointed at the two ends to a cross head A, which is itself jointed to a vertical
pivot D. The support D can in its turn pivot upon the carriage E, which can
move in the direction of the arc by sliding upon the fixed plate F. The arms B, B',
are insulated from each other and from the rest of the mechanism.
The carriage E is fitted with a dovetail in the plate F, and it is moved along
this plate by hand; a plate spring G interposed between the two pieces retains it
in the position which may be given to it. The support D rests upon the carriage
with a circular base furnished with an arm H, upon which the end of the regulating
screw I acts in opposition to a spring J. The contact of the support and the
carriage is secured by a spring K held by the axis L, upon which the support
pivots.
The cross head A is jointed at O to the top of the support D; it rests by its
weight and that of the arms B B' upon a cam M the axis of which is provided
with a milled head N, by which it can be operated by hand.
Lastly, the arms B B are fixed to the axles P P' carrying, in the interior of the
cross head A, toothed segments QQ operated by a single endless screw R. The
longitudinal play of this screw is obviated by an abutment spring S; other
springs T T push the bearings U U, which are of insulating material, towards
the centre and retain the endless screw in contact with the seginents.
The arrangement above described, by obviating all play between the parts,
enables the luminous point to he moved in any direction with the greatest precision;
it now remains to ensure the fixing of the carbons and their exact agreement with
each other by mechanism removed from the heat, which is obtained in the following
manner.
Each of the arms B B is tubular and has in the interior a rod 6 pressed by a
spring a against the carbon placed in the socket d. This rod, by pressing against
the carbon by its concave end, fixes it without the help of screws. At its opposite
end the rod 5 carries a pin e passing through a slot in the arm; it is only necessary
to move this pin backwards, aided by another pin f fixed in the arin, to release

page_text: the carbon, which falls by itself, and to introduce a new carbon which will be fixed
as soon as the pin e is released.
If the points of the carbons, brought to the desired distance apart by the
operation of the endless screw R, do not agree, they are regulated, on the one
hand in a longitudinal direction, by elongating or shortening the arm B' by
means of the screw V which causes it to slide upon an interior tube, and on the
other hand in a transverse direction, by inclining to the right or to the left the
arm B, which is hinged at X and carries in the fixed part an eccentric Y, which
acts upon the elongated arm of the hinge. The conductors Z, conveying the
current to the arms B B', are fixed by screw nuts Z see Fig. 2.
The crossing of the arms B B has an essential object which it is important to
state. It renders the moving of the luminous pointless considerable for the
same wear of the carbons. Suppose in effect the carbons at their maximum
wear, such as that indicated in dotted lines, in approaching each other, the
luminous point will come to y, whilst it would come to z if the common joint of
the arms were placed at the middle of P P¹..
I would have it understood that the details of construction of the apparatus
may be somewhat varied without departing from the peculiar character of the
invention.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In arc lamps, the arrangement of, apparatus substantially, as herein described
and for the purpose stated.
2. In arc lamps, the crossing of the arms carrying the carbons, their operation
by a single endless screw-to, regulate the distance apart of the carbons, their
mobility in both transverse and longitudinal direction for the correct adjustment
of the carbons in agreement with each other, and lastly the mode of fixing and
regulating the carbons by mechanism removed from the heat, substantially as
herein shown and described.
Dated this 28th day of December 1896.
HARRIS & MILLS,
23 Southampton Buildings, London, W.C.,, Agents.