LAM
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Lewis Thompson Wright at
the Office of the Commissioners of Patents on the 7th February 1883.
LEWIS THOMPSON WRIGHT of Beckton in the county of Essex,
IN SAFETY LAMPS
"
"IMPROVEMENTS
My invention relates to improved means whereby, firstly, the flashing of the
flame through the wire gauze of safety lamps is more or less prevented, and,
secondly, whereby the heating of the wire gauze, to a certain degree, automatically
effects the enclosure of the same so as to prevent access of the fire-damp thereto.
For these purposes, I, in the first place, employ in place of the ordinary wire
gauze, such as is now used for Davy and other lamps, a wire gauze woven after
the manner of basket work, that is to say, wherein the wires in one direction are
kept perfectly straight, while the wires in the other direction are woven in and
out of the former. By this means I am enabled, while using wire of a com-
paratively large gauge, and thus presenting a large body of metal for absorbing
heat, to weave the wires so closely together as practically to present no direct
openings through the gauze, but only comparatively small oblique or tortuous
openings, through which flame could not find its way except under considerable
pressure, greatly exceeding that which can occur in mines.
Wire gauze of this description however does not readily bend over in one
direction so as to form the folding joint ordinarily employed, and consequently, in
order to fix the circular cap forming the top of the cage to the cylindrical or
tapering part thereof, I employ a ring shaped clamp, of Ū section, which fits over
the meeting edges of the cylindrical part and cap, and is then beaten down close
upon them so as to form a tight joint.
In order to cut off the access of the fire damp to the gauze cage of the above
described or other forms of lamps when they become heated to a certain degree, I
surround the cage with a guard baving openings, which are provided with doors
or slides that are connected to a spring which, in its turn, is connected by a fusible
plug or connection to the cage of the lamp, so that when the cage becomes heated
to such a degree as to fuse the plug, the spring being released will close the doors
or slides, and thus shut off the access of the gases to the lamp. Or the guard may
be made in sections which are ordinarily expanded so as to leave openings between
them, and are caused to collapse so as to close these openings by the action of the
spring on the heating of the cage as described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lewis Thompson Wright in the Great Seal Patent Office on the
28th July 1883.
LEWIS THOMPSON WRIGHT of Beckton in the County of Essex
IN SAFETY LAMPS
13
"IMPROVEMENTS
My invention relates to improved means whereby the flashing of flame through
the wire gauze of Safety Lamps is prevented. For this purpose, I employ, instead
of the ordinary wire gauze, which, if fine in the mesh, is proportionally less
massive, and therefore less effective in cooling, a wire fabric woven after the
manner of basket work, as shewn in Fig. 1 of the accompanying drawings, which
represents a piece of the fabric of natural size, and in the magnified view and
section Figs. 2 and 3. The wires a running in the one direction are of strong
material and are kept quite straight, while the light and more flexible cross
wires b are woven in and out of the former. By this means, I am enabled, while
using wires of comparatively large gauge presenting a large body of metal for
absorbing heat, to weave the cross wires so closely together as practically to
present no direct openings, but only comparatively narrow oblique and tortuous
passages through the fabric, so that flame cannot find its way through from one
side of the fabric to the other, except under considerable pressure, greatly exceeding
that which can occur.in mines.
As wire fabric thus woven does not readily bend over so as to form the folded
joints usually employed for wire gauze, I fix the circular top of the cage to the
cylindrical side as shewn in Fig. 1, where the cylindrical fabric c is turned out at
the top to form a small lip or flange and a ring d of U section is fitted over the
edge of this flange and of the circular top and pressed or beaten down closely upon
them, so as to form a tight joint.
Having thus described the nature of my invention and in what manner the
same is to be performed, I claim :—
The use in Safety Lamps of a wire fabric woven like basket work, substantially
as and for the purpose herein set forth.
In Witness whereof I the said Lewis Thompson Wright have hereunto set my
hand and seal this twenty fifth day of July in the year of Our Lord One Thousand
eight hundred and eighty three
LEWIS THOMPSON WRICHM Gal
LEWIS THOMPSON WRICHT
(L.C.)