Improvements in Lenses and Electric Lamps, more especially intended for Use for Theatrical Stage Purposes.
Year: 1894

page_text: Date of Application, 7th Sept., 1894
Complete Specification Left, 7th June, 1895-Accepted, 20th July, 1895
PROVISIONAL SPECIFICATION.
Improvements in Lenses and Electric Lamps, more especially
intended for Use for Theatrical Stage Purposes.
We
Walter PfeffeR DANDO of The Palace Theatre, Shaftesbury Avenue,
Stage Manager and JAMES EGLINTON ANDERSON GWYNNE of Brooke Street
Works, Holborn, both in the County of London, Engineer do hereby declare the
nature of our invention to be as follows:-
The object of this invention is to provide lenses and electric lamps more
especially intended for use for theatrical purposes the lamps being arranged so that
they can be readily manipulated and regulated by hand and lenses being provided
which give a better lighting effect than is obtainable with the ordinary lenses:
According to our invention we make the lamp with carbon holders capable of
being moved along a rod or support in either direction by means of a screw
provided with a hand wheel or its equivalent for turning it the said screw being
made with right and left handed portions, one portion engaging with a screw nut
carried by one carbon holder and the other portion engaging with a screw nut
carried by the other carbon holder so that when the screw is rotated by the hand
wheel or the like the two carbons are caused to approach towards, or recede from,
each other simultaneously. By differentiating the pitches of the two screwed
portions one carbon can be made to move at a different rate from the other if
desired. A pointer may be used on a fixed' part of the lamp to indicate the proper
position for the arc relatively to the lense. Means are also provided whereby one
of the carbons can be moved in striking the arc. This preferably consists of
a sleeve carrying the carbon and mounted so that it can be moved longitudinally in
the carbou holder proper a pin on the said sleeve projecting through a slot in the
holder proper and engaging with the slotted end of a lever centered to the carbon
holder the other end of the said lever constituting a handle by which the sleeve and
carbon can be moved longitudinally in the holder in striking the arc. Stops may
be provided to limit the movement of the lever or of the sleeve in each direction.
The lamp is set in a suitable box preferably in an inclined position so that the light
is presented to the lens in the most favourable position. The lamp is preferably
made so that it can be conveniently slidden into place in the box and removed
therefrom. This can be done by mounting the said lamp on a base which is fitted
to slide between undercut guides one of which is pivotted so that by ineans of
a screw at the exterior of the box it can be caused to clamp and unclamp the base
of the lamp, a slot and pin if necessary being provided to guide it in its movement.
The lense is mounted in an opening in the box. Ordinary lenses give objectionable
rings of light on the stage or other place whereonto the light is thrown. To obviate
this we obscure the lense or render it translucent from its edge or periphery to
some little distance inwards towards its centre, the degree of obscuring being
preferably reduced gradually as it approaches towards the centre. This can be
most conveniently done by painting or by silvering or by grinding the glass of the
lense at the said part or we may grind the periphery or edge of the lensé or make
it flat, and if necessary colour or silvering can be applied at this flattened or
ground down part. In order to overcome where necessary the whiteness of the
electric light we may tint the lense or an intervening glass so that the light may be
slightly tinged as desired.
Dated this 7th day of Sentember 1894

page_text: Improvements in Lenses and Electric Lamps, more especially
intended for Use for Theatrical Stage Purposes.
We, WALTER PFEFFER DandoO of The Palace Theatre, Shaftesbury Avenue,
Stage Manager and JAMES EGLINTON ANDERSON GWYNNE of Brooke Street
Works Holborn Civil Engineer both in the County of London 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 this invention is to provide lenses and electric lamps more
especially intended for use for theatrical purposes but applicable to other purposes
such for example as for use in magic lanterns and the like the said lamps being
arranged so that they can be readily manipulated and regulated by hand and lenses
being provided which give a better lighting effect than is obtainable with ordinary
lenses.
We will describe this invention with reference to the accompanying drawings
Figure 1 shewing a side elevation and Figure 2 a plan of a lamp arranged
according to this invention without its case.
Figures 3 and 4 are sections shewing the upper and lower carbon holders
respectively.
Figures 5 and 6 are back and front views of the lamp in its case.
Figure 7 shews in side view & section a modification as hereinafter described
and
Figures 8 and 9 illustrate the improvement in the lense.
According to our invention we make the lamp with carbon holders A and B
capable of being moved along a rod or support C in either direction by means of a
screw D provided with a hand wheel or its equivalent for turning it, such for
example as the milled head e on the rod E provided with a bevel wheel gearing
with bevel wheel d on the screw D, the said screw D being made with right and
left handed portions one portion engaging with a screw-nut a carried by the carbon
bolder A and the other portion engaging with a screw nut 6 carried by the other
carbon holder B so that when the screw D is rotated by the milled head e and
gearing or the like the two carbons x and y are caused to simultaneously approach,
or recede from, each other. By differentiating the pitches of the two screwed
portions of the screw D one carbon can if desired be made to move at a different
rate from that at which the other moves. A pointer or index may be used on a
fixed part of the lamp to indicate the proper position for the are relatively to the
lense. The movement of one of the carbons for striking the arc may be effected
by making the carbon slide easily in its holder and keeping it in position by means
of a ball situated in an opening in the side of the holder and pressed onto the
carbon by a spring which will allow of the carbon being moved by hand in its
holder or the carbon may be mounted in a sleeve g as shewn in Figure 7 sliding in
the carbon holder so that it can be moved longitudinally in the carbon holder
proper A, a pin h on the said sleeve projecting through a slot i in the holder proper
and engaging with the slotted end of a lever jcentred at ³ to the carbon holder the
other end of the said lever constituting a handle by which the sleeve and carbon
can be moved longitudinally in the holder in striking the arc. Stops may be
provided to limit the movement of the lever, or of the sleeve, in each direction.
The parts may be supported and the current be led to the carbons in any suitable
manner. We have shewn the rod C as being secured in a block on the base L
and the screw D as being carried in bearings in the said block and in a piece c
projecting from the upper end of the rod C. The electric connection to one carbon
may be made by a wire connected to the binding screw at q the current passing
thence through. the metal of the apparatus to the carbon. The connection for the

page_text: other carbon may be made by a wire connected to the binding screw the current
passing through the strips and wire t secured to the front portion of the carbon
holder which is insulated from the rear portion (which is in contact with the metal
of the apparatus) by means of mica, or other insulating material, as at u.
The lamp is set in a suitable box K preferably in an inclined position, as shewn,
so that the light is presented in the most favourable position. The said box can be
carried by trunnions, or screws, in a stand as shewn to allow of adjustment of its
position. The lamp is preferably made so that it can be conveniently slidden into
place in the box and removed therefrom. This can be done by making the base L
fitted to slide between undercut guides m, one of which is pivotted, so that, by
means of a screw n, at the exterior of the box K, it can be caused to turn on its
pivot, and clamp, or unclamp, the base of the lamp, as required a slot and pin
if necessary being provided to guide it in its movement. The lense P is mounted
in an opening in the box. Ordinary lenses give objectionable rings of light on the
stage or other place or object whereonto the light is thrown. To obviate this we
partially obscure the lense from its edge, or periphery, to some little distance
inwards towards its centre, the degree of obscuration being preferably reduced
gradually as it approaches towards the centre. This is illustrated by Figures 8
and 9 shewing a lense in front view and in section the partially obscured part being
This part may be partially obscured equally throughout but we
prefer to make the degree of obscuration less as it approaches towards the part w.
The partial obscuration can be most conveniently done by grinding the glass of the
lense at the said part, or it can be done by means of semi-opaque varnish. The
partial obscuration may be applied to both surfaces of the lense or to only one of
them. In order to overcome where necessary the whiteness of the electric light
we may tint the lense or use an intervening glass so that the light may be slightly
tinged as desired.
from v to 10.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. An electric lamp consisting of the arrangement and combination of parts
substantially as hereinbefore described and illustrated in Figures 1 and 2 of the
accompanying drawings.
2. In electric lamps carbon holders mounted upon a rod tube or slide and
provided with nuts engaging a reversely threaded screw provided with means for
rotating it so that the carbous can be simultaneously caused to approach, or recede
from, each other by the rotation of the said screw; substantially as herein before
described.
3. In combination with electric lamps arranged as claimed by the preceding
second claiming clause means for striking the arc substantially as herein before
described and illustrated in Figure 7 of the accompanying drawings.
4. A lense for the purpose described the said lense having a part of its surfaces,
or of one of its surfaces, from the edge inwards partially obscured substantially as
herein before described.
5. A lense for the purpose described the said lense having a part of its surfaces,
or of one of its surfaces from its edge inwards partially obscured the degree
of partial obscuration decreasing towards the centre of the lense substantially as
hereinbefore described.
Dated this 7th day of June 1895.
JOHNSONS & WILLCOX,
Agents.