Improvements in Portable Electric Safety Lamps.
Year: 1889

page_text: Date of Application, 21st May, 1889-Accepted, 13th July, 1889
COMPLETE SPECIFICATION.
Improvements in Portable Electric Safety Lamps.
I, LARS BRISTOL, of Acacia Villa, Park End, Bromley, in the County of Kent,
Electrical Engineer, 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 certain improvements in the construction arrangement and
combination together of parts forming portable electric safety lamps such as miner's
and reading lamps, the object being to provide a handy safe convenient and inexpensive
article for the purpose.
Two typical lamps constructed according to my invention are illustrated in the
accompanying drawings. Figure 1 is a front elevation of a portable safety miners
lamp, Figure 2 a sectional elevation thereof, and Figure 3 a full size view of the
circuit arrangement.
Within a strong casing A of wood metal or suitable material a closed secondary
battery B, such for example as is described in the specification accompanying my
application for Letters Patent No. 9845 A.D. 1888, is fixed and connected so as to be
charged by the prime generator at the terminals a a". I may use any number of
cells from two to six but I find three or four most suitable.
The case A is enclosed by a strong lid A' of brass or other suitable metal provided
with a handle a¹ and having a raised channel a² open at its end for escape of gases
from the electrolyte through any suitable gas plug such as b. The lid A¹ has a small
lug a³ covering the terminal a to prevent tampering and is secured by a lock device
upon the enlarged end or boss of a similar lug a This consists of a screwed
spindle a with squared head for usual key which is held in the boss at by a screw
ring a as illustrated.
The screw a engages threaded hole a in an extension of the back plate C
containing the circuit arrangements and upon which is cut a male screw thread for
receiving the female screw in the metal rim d carrying the hollow lens or bulls-eye
glass D. Upon the rim a pin d' is fixed which when the rim is screwed tight fits
a corresponding hole as in the boss a', so that when the lid is shut and locked the
cap D cannot be unscrewed: Inside rim d a plain disc d is fitted as a reflector upon
which is fixed the spring holder d³ for the bottom of the glow lamp L whose terminals
are retained upon a couple of spring holders having hooked ends splayed outwards
sufficiently to secure the lamp L firmly yet easily removable. The holders
attached the one to the positive terminal P of the battery and the other to
an independent plate n between which and the negative terminal N of the battery,
circuit is made and broken by the spring sliding switch S passing through a groove
behind the plate C and limited in movement by the stops sl. The negative .battery
terminal a may be arranged in the switch S as illustrated or it may be arranged
similarly to the positive terminal a³ and covered by a similar lug projecting from the
lid. The back plate C may conveniently be cast with the projections NH s¹ as
illustrated.
are
Figure illustrates a general view of a portable safety reading or drawing room
lamp, Figure 5 shows a modified arrangement of the parts illustrated in figure 3, and
Figure 6 is a cross sectional view thereof.
The arrangements are similar to those above described for the miners lamp and the
same reference letters are used..
In this case the plate C is covered by a plain screw cap d and the glow lamp L is
affixed to an ornamental metal standard T with usual shade such as illustrated.
The standard T carries an insulating block t having affixed the spring contact
maker t¹. The standard is detachably fitted into a corresponding hole in plate C
D
077

page_text: and takes the position shown in figure 5. Contact is made between the pole P and
standard foot T by switch S and the current passes up through the standard and lamp,
returning by an insulated wire w and connection t¹ to pole N.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. The arrangement and combination of parts forming portable safety electric lamps
substantially as described and illustrated in the drawings hereto annexed.
2. The provision in combination with the lid of a portable electric lamp such as is
hereinabove set forth of a lug or lugs a³ covering one or both terminals of the battery
and a bossed lug at containing a lock constructed as described and illustrated and with
or without a gas escape piece a².
3. In a portable electric lamp such as specified the combination with the battery B
casing A and lid constructed as described and claimed in (2) of plate C lamp L screw
rim with pin d¹ bulls eye glass D and circuit arrangements as and for the purpose
setforth.
4. The specific contact and circuit arrangements for the portable electric lamp
described in reference to figures 4, 5 and 6 as setforth.
Dated this 21st day of May 1889.
J. C. CHAPMAN, Fel. Inst. Patent Agents,
70, Chancery Lane, London, W.C., Agent for Applicant.