Improvements in Optical Lanterns.
Year: 1893

page_text: Date of Application, 23rd May, 1893
Complete Specification Left, 23rd Feb., 1894-Accepted, 21st Apr., 1894
Improvements in Optical Lanterns.
I, LAMBERT MATTHEWS of Strafford House, Hadley Green, Barnet, in the
County of Middlesex, Gentleman, do hereby declare the nature of this invention to
be as follows:-
My invention relates to improvements in the construction of optical lanterns
used for the projection upon a screen of photographic and other pictures, and the
invention has for its object to enable the apparatus to be so lightly constructed and
to be packed in such a small compass as to be easily portable and yet when erected
for use to possess the strength and stability of the heavy and cumbrous apparatus
now employed.
The framework of the apparatus on which the objective, the condenser, the
slide carrier stage, and the burner, are carried consists of two base blocks or feet
held at the proper distance apart by longitudinal tubular rods fitted to slide
through the base blocks so as to be readily detachable therefrom and upon which
the rear base block carrying the condenser and slide carrier stage is adjustable in
the fore and aft direction to suit the focal length of the objective. Upon each
base block is erected a pair of tubular pillars acting as distance pieces for tie rods
passing up loosely through the base blocks and pillars and provided with heads at
the lower, and tightening nuts at the upper, ends, the pillars being braced at top by
cross and longitudinal bars secured by the same nuts, the longitudinal bars being
slotted to permit of the fore and aft adjustment above referred to.
The front on
which the objective lens carrier is mounted has grooved edges fitting between the
front pair of pillars and the condenser is clamped in a hoop which as well as the
slide carrier stage is supported by sockets fitting tightly on the rear pair of pillars
and capable of sliding thereon to permit the independent vertical adjustment of the
condenser and slide carrier stage. All the parts of this framework are readily
separable for transport and are readily put together for erection, it being only
necessary to throw a cloth over the frame to prevent dispersion of the light when
the lantern is in use.
The burner is supported on a carrier provided with sockets fitting on the rear
ends of the main tubular longitudinal rods which project behind the rear base block
and upon which the burner carrier is adjustable in the fore and aft direction, the
burner being fitted to slide laterally upon a part of the carrier which is itself
supported by adjusting screws, provision being thus made for the fore and aft,
lateral, and vertical adjustment of the burner. The burner is enclosed in a lantern
body whose four sides are hinged together, so that they may be collapsed diamond-
wise and are rigidly held in the expanded square form when erected for use by the
tep of the body engaging with two opposite sides either by means of guide grooves
if the top be fitted to slide or by the top being hinged to one side and engaging
with the opposite side or with one of the adjacent sides, the front side of the body
being provided with a flanged aperture fitting on the condenser mount whereby the
lantern body is supported.
The slide carrier frame is fixed upon its stage by means of a dovetailed plate on
the one fitting between corresponding gibs on the other whereby a firm and secure
connection is effected without the use of springs, whereby fixity of the luminous

page_text: disc on the screen is ensured and coincidence of the discs when two lanterns are
used is readily obtained.
Dated this 23rd day of May 1893.
L. MATTHEWS,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Optical Lanterns.
I, LAMBERT MATTHEWS, of Strafford House, Hadley Green, Barnet, in the
County of Middlesex, Gentleman, 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 :-
My invention relates to improvements in the construction of optical lanterns
used for the projection upon a screen of photographic and other pictures, and the
invention has for its object to enable the apparatus to be so lightly constructed and
to be packed in such a small compass as to be easily portable and yet when erected
for use to possess the strength and stability of the heavy and cumbrous apparatus
now employed.
The invention will be described with reference to the accompanying drawings,
forming part of this Specification wherein
Figure 1 is a side elevation of the apparatus erected for use; Figure 2 is a plan
of the same;
Figure 3 is a cross-section, on line 3-3 Figure 2, shewing the slide carrier and
its stage in elevation ;
Figure 4 is a vertical section of the carrier and its stage, on line 4-4
Figure 3;
Figure 5 is a cross-section, on line 5-5 Figure 2, shewing the condenser and its
base block in elevation ;
Figure 6 is a cross-section, on line 6-6 Figure 2, shewing the adjustments of
the burner stage;
Figure 7 shews a plan of the collapsible lantern body as arranged for use.
Figure 8 is a top view with the cover removed and the sides partially collapsed.
The framework of the lantern consists of two base blocks or feet A, B, and of
a pair of longitudinal tubular rods C each constructed of two members fitted to
slide telescopically the one in the other, the members c' of smaller diameter being
rigidly fixed in the front base block A whilst the members of large diameter
are free to slide through the rear base block B. The objective carrier or front D
has grooved edges which slide between a pair of channelled pillars E fixed to and
rising from the front block A whilst the rear block B forms a cradle in which
the condenser G is firmly held by a partially-encircling band H' fixed to the
block B permanently at one end and at the other by a binding screw and slot
admitting of the band being released, as shewn in dotted lines, in order to replace
the condenser in case of need.
A third block H is supported on the members c² of the pair of telescopic rods C
on which it is free to slide. This block H carries the stage I to which the slide
carrier frame K is fixed by means of the projecting edges of a plate k fixed to its
underside, fitting firmly between corresponding gibs i formed by thin brass plates
fixed to the two faces of the stage I whereby a firm and secure connection is
obtained without the use of springs, and fixity of the luminous disc on the screen
is ensured. The plate k is slightly tapered in width towards the ends to admit of
its being easily introduced between the gibst and slid transversely until properly
adjusted in a central position. The stage I is connected to its base block H by

page_text: slotted end plates and binding screws L which enable the stage to be raised to
the proper level to suit the size of slide, without the use of loose packing slips as
usually employed. Springs S are also fixed to the stage I for use with chroma-
tropes or other framed slides.
The burner is supported on a carrier or stage M provided with sockets m fitting
on the rear members of the longitudinal tubes C which project beyond the rear
base block B and upon which the burner carrier is adjustable in the fore and aft
direction. The burner N is of the usual construction employed for the oxy-
hydrogen light, n¹ n² being the gas tubes, n³ the lime block spindle, and n' the
gear for revolving it. This burner is carried by a cross-piece O supported so as
to be capable of vertical adjustment by nuts P upon screw pillars p fixed to the
carrier M, provision being made for the lateral or transverse adjustment of the
burner by the ends of the cross-piece O having slots o for the pillars p to pass
through and being clamped rigidly in position, by binding nuts 9, so that the
burner cannot be accidentally moved aside as may happen when the burner is
pivoted as usual. The burner may be enclosed in a sheet metal hood R of any
ordinary kind, held in clips r fixed to the condenser carrier.
Or a hood or lantern body, such as shewn in Figure 7, may be employed. The
four sides T of the body are of sheet metal hinged together at t so that they may
be collapsed diamond-wise and are rigidly held in the expanded form when erected
for use by the top U engaging with two opposite sides either by means of U shaped
guide grooves u (Figure 7) if the top be fitted to slide or by the top being
hinged to one side and engaging with the opposite side or with one of the adjacent
sides, the front side of the body having an aperture with flanges fitting in the
clips on the condenser carrier.
By means of the various sliding motions of the base blocks or carriers afforded
by the tubes C perfect adjustment to suit the focal length of the objective and the
necessary distance of the illuminant from the condenser and its adjustment
vertically and laterally in relation thereto may be readily obtained whilst the
apparatus may be packed in a small compass so as to be easily portable.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described construction of the adjustable frame supporting the
objective, the condenser, the slide carrier stage, and the burner, with capability of
longitudinal sliding adjustment, consisting of a pair of telescopic tubular rods
passing through base blocks or carriers, as specified.
2. The cradle-like support for the condenser, in combination with a band
passing over the top of the condenser to secure it therein, as specified.
3. The combination, with the slide carrier, of its stage or support capable of
independent vertical adjustment and the means of connecting the two together,
substantially as specified.
4. The burner carrier constructed to afford adjustment of the burner in the
longitudinal, vertical, and transverse directions, substantially as specified.
5. The collapsible lantern body or hood substantially as specified.
L. MATTHEWS,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.