Improvements in Portable Electric Lamps, More Especially Intended for Miners' Use.
Year: 1890

page_text: Date of Application, 22nd Aug., 1890-Accepted, 11th Oct., 1890
COMPLETE
SPECIFICATION.
Improvements in Portable Electric Lamps, More Especially Intended
for Miners' Use.
We THE MINING AND GENERAL ELECTRIC LAMP COMPANY LIMITED of
11 Abchurch Lane in the City of London and WILLIAM MOSCROP of 64 Milbank
Street in the City of Westminster Mechanical 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 improvements upon electric lamps such as are described in
the Specification of the Application for Letters Patent No. 3094 dated 26th February
1890.
According to the present invention we make the incandescence lamp bulb itself or
the protecting glass which covers it or both of them so that they are held in their
protruding position by a spring or springs which on a blow or pressure upon either or
both of them occurring will allow either or both of them to yield and so prevent their
fracture or render them less liable to fracture than would otherwise be the case.
This may
be effected by placing behind the protecting glass or behind the reflector
through which the bulb protrudes the spring or springs so that the said glass can
retreat to within its casing on the occurrence of a blow or of undue pressure.
To allow of the bulb yielding we may attach it to flexible leads and secure it to an
annulus or perforated plate situated in the casing of the protecting glass and forced for-
ward by the spring or springs whereby the bulb is protruded through the opening in the
reflector so that it will retreat into the recess behind it on the occurrence of a blow or
undue pressure.
When a sliding lid for the body of the lamp is used provided with
a handle we add to the handle a projection which when the lid is slidden into place
and the handle is turned up engages with the body part of the lamp so that the lid is
not liable to be accidently slidden off if it should have been left unlocked.
The elements may be of any desired kind but they are preferably of what is known
as "lithanode" and the connections to the peroxide element may consist of a washer
or washers of platinum pressed into close contact with the plates by means of elastic
washers and bolts and nuts. A platinum wire may form the connection of the
element with a leaden strip which is used to conduct the current to outside the cell.
The accompanying drawing represents a vertical section of a miner's lamp with the
present improvements combined therewith. In this drawing the protecting glass and
the bulb are both shewn capable of being moved back on the occurrence of a blow or
pressure which would otherwise be liable to break them but it is to be understood
that they may both be so arranged or if desired either the protecting glass or the bulb
alone may be so arranged.
A is the bulb of the lamp which is attached to the flexible leads a from the battery
of the lamp. The bulb A is secured to and protrudes through a central opening in
the insulating disc b. D is the protecting glass which is held in the casing e the front
edge of which is turned inwards or so formed as to retain the glass Ď. f is the
reffector. Between the disc b and the lamp casing the spring c is interposed.
On the occurrence of any blow or undue pressure upon the glass D the spring c
will yield and the glass D will retreat to within the casing e. If this glass should be
broken then any blow or pressure upon the bulb will also cause the spring c to yield
and the bulb will retreat.'
If the bulb only is to be made capable of retreating on the occurrence of a blow or
undue pressure if the glass D be broken then it will simply be necessary to secure the
glass and reflector rigidly in the casing e.
The handle H of the lamp is attached to the sliding lid I and one of the uprights /
provided with a piece h² projecting beyond one of the centres ³ on which the uprights
When the lid is slidden into place and the handle is turned up the projection h³
Gurn.

page_text: takes up such a position (as shewn) that it forms a stop bearing on the lamp body to
prevent the lid I from being slidden off until the handle is turned down thus
preventing the lid accidentally coming off if the lock i which secures the lid in
place be not fastened.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is --
I
1. In portable electric lamps the combination with the protecting glass or with the
bulb or with both of them of a yielding device which will allow of them or either of
them retreating on the occurrence of a blow or undue pressure substantially as
herein before described.
'
2. In portable electric lamps having a sliding lid provided with a handle centered
thereto a projection or stop such as h² for preventing the lid from accidentally becoming
detached substantially as herein before described.
Dated this gond lan
1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents