Improvements in Incandescence Electric Lamps.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Incandescence Electric Lamps.
FREDERICK JAMES SATCHWELL 4 Crescent Villas Crescent Road South
Woodford Essex Electrician, do hereby declare the nature of this invention to be
as follows:-
An invention for a high or low voltage electric incandescent lamp principally
high voltage the filament of which is either spiral or zig-zag form in horizontal or
vertical position through the centre of which runs a glass mica or other suitable
tube or solid piece the end of which falls in the seal off or other suitable place thus
keeping it firm. The terminals of the leading in wires may be one at each end of the
lamp or both at one end. The inside tube is either silvered or transparent. One
leading in wire may pass down the inside of the tube which I prefer it to do.
Dated this 14th day of October 1896..
FREDERICK JAMES SATCHWELL.
I FREDERICK JAMES SATCHWELL of 4 Crescent Villas Crescent Road South
Woodford in the County of Essex, Electrician 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 :--
This invention relates to electric incandescence lamps and particularly to high
voltage lamps and has for its chief object the provision of means for supporting
the filament in such a manner as to prevent contact of the coils or convolutions
thereof with the bulb and so as to prevent excessive vibration of the said filament
while allowing of the long slender filament required in a high voltage lamp.
In high voltage lamps the filament is necessarily very long and very slender, and
in practice it is usually formed in coils or in a gridiron or zigzag shape or two
filaments are joined in series. Now with such a construction the filament is liable
to bend and touch the sides of the bulb when the latter is held in a horizontal
position so that when the current is passing, the glass is liable to be fractured and
the lamp thus destroyed; or one filament is liable to touch the other, or one coil
or convolution of the filanient to touch another coil or convolution and so produce a
short-circuiting and destruction of the filament. Moreover owing to the thinness
of the filament and the amplitude of the vibrations it is possible for it to make in
the bulb, the filament is very liable to break at its junction with the leading-in
wires where the leverage is greatest; therefore very great care is required in
effecting the transit of high voltage lamps, as well as in the use of such lamps and
many lamps are rendered useless by the breakage of the filaments during transit
however carefully the transit has been effected. A further objection to such lamps
constructed as heretofore is that they produce flat lights.
By my invention I overcome all of these objections without diminishing the
efficiency of the lamp.

page_text: Referring to the accompanying drawings,
Figure 1 is a side elevation of an electric incandescence lamp constructed
according to my invention,
Figure 2 is a section of one form of tube I sometimes employ in the lamp for
supporting the filament, and
Figure 3 illustrates a modification hereinafter described.
Like letters of reference denote corresponding parts in the several figures.
A is the bulb, B, B are the leading-in wires, C is the filament which is shown
possessing a spiral formation but it may have a gridiron or zigzag shape arranged
in two main branches. D is a rod or tube of glass, mica or other suitable material
extending through the spiral filament and supported within the bulb in any suitable
manner, for example it may be sealed to the bulb or held by wires, or one end of
the rod or tube may be arranged to rest in the seal-off of the bulb, the other end
being attached to the leading-in wires as shown. The leading-in wires may both
enter the bulb at one end or one may enter the bulb at one end and the other at
the other end. In the former case one leading-in wire extends either down the
interior of the tube D and out through a hole at the side or along a longitudinal
groove d in the side of the rod or tube D and is then united to the remote end of
the filament. By these means the possibility of short-circuiting the filament is
avoided. The above construction allows of the attainment of ample length of
filament for high voltage lamps and at the same time ensures that the vibrations
of the filament in transit and at other times shall be so limited as not to endanger
the filament by causing excessive strain at the junction thereof with the leading-in
wires. Moreover it is obvious that there is no risk of cracking the bulb by contact
therewith of the incandescent filament since the movements of the latter are limited
by the inner rod or tube. The said rod or tube may be trausparent or it may be
silvered to act as a reflector.
The filament may if desired be arranged across the bulb instead of longitudinally
therein.
In lieu of the internal rod or tube D within the coil if it is spiral or between the
two main branches of the filament if it is made of zigzag shape, I may use a tube E
of glass or mica or other similar material around and enclosing the filament as
indicated in Figure 3, one leading-in wire being preferably arranged outside the
tube to avoid short-circuiting. This method answers very well for supporting the
filament but otherwise it is not so good as the method first described inasmuch as
the outer tube absorbs a portion of the light.
The convolutions of the filament are widely separated and not liable to short
circuit however the lamp may be held; moreover the light emitted by them is
equally diffused throughout the bulb no flat side being presented as in ordinary
lamps heretofore made.
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 :-
1. In an electric incandescence lamp a rod or tube extending through or between
the coils or branches of the filament, or a tube enclosing the filament, for the
purposes specified.
2. An electric incandescence lamp constructed substantially as described with
reference to Figure 1 or to Figure 3 of the accompanying drawing, for the purposes
specified.
Dated this 0th den
100
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.