Year: 1897

page_text: We, BERNARD MERVYN DRAKE and JOHN MARSILALL GORHAM (trading as
Messrs. Drake & Gorham), 66, Victoria Street, Westminster, London, S.W., Elec
trical Engineers, do hereby declare the nature of this invention to be as follows:-
-
The object of our invention is to enable a longer life to be obtained than is
possible with the ordinary arrangement of bottom carbon fixed in the inner globe.
In such case when the carbon is of full length the arc is at the top of the inner
globe, and when burned out it is at the bottom, the life being limited by the
length of the inner globe itself.
By our arrangement we place two gas checks on the inner globe, one at the
bottom and the other at the top and we support the inner globe preferably by
the lower gas check, the carbons then feeding through both ends both downwards
and upwards in the ordinary way adopted in open arc lamps.
11
The central portion of the bottom gas check is made with some lateral play to
the sanhana
We, BERNARD MERVYN DRAKE and JOHN MARSHALL GORHAM (trading as
Drake and Gorham), both of No. 66, Victoria Street, Westminster, Electrical
Engineers, 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:-
The object of our invention is to enable a longer life to be obtained than is
possible with the ordinary arrangement of bottom carbon fixed in the inner globe.
In such case, when the carbon is of full length the arc is at the top of the inner
globe and when burned out it is at the bottom, the life being limited by the
length of the inner globe itself.
By our arrangement we place two gas checks on the inner globe, one at the
top and the other at the bottom, and we support the inner globe preferably by
the lower gas check, the carbons then feeding through both ends both downwards
and upwards in the ordinary way adopted in open arc lamps.
The central portion of the gas check is made with some lateral play to allow of
the centering of the carbons.
The annexed drawings and the following description set forth the mechanical

page_text: details embodied in the principle of the invention. Change may be made in the
same provided the principles of construction hereinafter referred to are employed.
In the said drawing the figure represents a vertical section of one form of
the improved device, shewing the carbons feeding through both ends, both
upwards and downwards, of the inner globe or cylinder.
In the drawing A and A¹ represent the top and bottom carbons
respectively and B, B¹, the two gas checks fitted on the globe or
cylinder C. The lower gas check B', supporting the globe C, is fixed
by any suitable means to a cross bar D, clamped or otherwise fastened to the two
guide rods E on which the carbon holders slide. Both gas checks have one or
more metallic diaphragms b, 61, closely fitting round the carbons and loosely fixed
centrally with them by means of screws or any other convenient manner, so
that they will adjust themselves to any slight variation from the central position
without causing the carbons to stick. The diaphragms have bevelled recesses
as shewn, their object being to retard the escape of gases from the inner globe,
at the same time causing as little friction as possible to the carbons.
Having now particularly described and ascertained the nature of our said in-
vention, and in what manner the same is to be performed, we declare that what
we claim is:-
In an enclosed arc lamp the use of an arc enclosing chamber with gas checks
both top and bottom through which the carbons may freely work...
Dated this 26th day of February 1898
B. M. DRAKE,
JOHN MARSHALL GORHAM..