Improved Means of Automatically Locking Shutters of Photographic Dark Slides.
Year: 1893

page_text: Date of Application, 15th May, 1893
Complete Specification Left, 15th Feb., 1894-Accepted, 14th Apr., 1894
PROVISIONAL SPECIFICATION.
Improved Means of Automatically Locking Shutters of
Photographic Dark Slides.
WILLIAM FREDERICK FLETCHER 60 Stanmore Road, Edgbaston, Bir-
mingham, Gas Engineer, ELISHA JOHN BRYANT DANKS, 1 Trafalgar Place,
St. Marks Street Birmingham, Gas Engineer, do hereby declare the nature of this
invention to be as follows
An improved means for automatically locking shutters of photographic dark
slides, so as to prevent any risk of exposing the plate a second time. It consists of
two portions, the one, being fitted to the body of the dark slide, & the other, to
the shutter. The portion screwed to the body consists of, a plate of metal, cut in
such a shape as will allow a small arm being bent at an angle that will allow of it
being parallel with the shutter of the dark slide, a loose arm, and coil spring, fitted
on a rivet, in a manner best suited for the said spring to act on the loose arm, so
that it will throw it forward when riveted to the small arm of the plate, herein-
before described. The said loose arm, is cut in such a shape as to form two
openings (on one side) of the most suitable description, for the purposes hereinafter
mentioned, the lower one being used for setting the lock, and the upper one for
catching over the pin, on the portion which is attached to the shutter.
The said second portion consisting of a plate from which a pin projects. The
whole is made use of in the following manner, when placing a plate in the dark
slide the shutter is slightly raised and the loose arm pulled right back, the shutter
is then pushed back and the pin attached to same, falls into the lower groove which
is now held uppermost and thereby holding back the said loose arm, it is now ready
for use and acts in the following manner, viz. :-On raising the shutter to expose
the plate (when fixed in camera) the pin attached to shutter is drawn out of the
lower groove thereby releasing the said loose arm, which, acted upon by the spring,
is thrown forward into position, so that on again closing the shutter, the pin is
forced into the second and upper groove, which is so formed that it acts as a lock
and thereby prevents the exposure of the plate a second time.
Dated this Thirteenth day of May 1893.
WM. F. FLETCHER.
E. J. B. DANKS.
COMPLETE SPECIFICATION.
Improved Means of Automatically Locking Shutters of
Photographic Dark Slides.
WILLIAM FREDERICK FLETCHER 60 Stanmore Road, Edgbaston, Bir-
mingham ELISHA JOHN BRYANT DANKS, 20 Bridge Road, Gravelly Hill, near
Birmingham, formerly of 1 Trafalgar Place St. Marks Street Birmingham, Gas
Engineers, 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 consists of improvements in automatically locking shutters of dark
slides after operating, thereby preventing a double exposure and the objects of
this invention are to simplify the construction of the said photographic dark slide
shutter lock, and to render it more reliable and effective.

page_text: We will now more particularly describe our invention, in the following manner,
which will be better understood by referring to the accompanying drawings in
which the same letters of reference indicate corresponding parts in all the
figures.
The plate F in which are three holes G, H, and L, Fig. 4, is fastened on the
body of dark slide with two screws passing through holes G & H.
The said plate being cut in such a shape as will allow a small arm being bent at
an angle, to bring it when fixed parallel with the shutter of dark slide. "A loose
arm E, Fig. 3, and coil spring K Fig. 5 being fitted on a rivet J Fig. 6 in a manner
best suited for the said spring to act on the loose arm so that it will throw it
forward when rivetted to the small arm of the plate F herein before described, the
said loose arm E is cut in such a shape as to form two openings, B and C, of the
most suitable description for the purpose hereinafter mentioned, the lower one, C,
being used for setting the lock and the upper one B for catching over or locking
the pin or small screw A. Fig. 7, on the opposite side to the openings, a piece of
metal is bent over to form a thumb bit D and in the centre of plate a hole M is
pierced to allow of rivet J being passed through.
The whole is made use of in the following manner; when placing a plate or plates
in the dark slide, the shutter is slightly raised and the loose arm E pulled right
back the shutter is then pushed down and the pin attached to same falls into the
lower groove C which is now held uppermost, thereby holding back the said loose
arm, Fig. 1. It is now ready for use and acts in the following manner, on raising
the shutter to expose the plate, the pin A attached to the shutter is drawn out of
the lower groove C, thereby releasing the said loose arm E, which, acted on by the
spring K is thrown forward into position so that on again closing the shutter the
pin A is forced against the incline N on arm E which guides pin A into the upper
groove B the said groove being so formed that it acts as a lock, Fig. 2, and thereby
prevents the exposure of the plate a second time. The drawings shew what we
consider to be the best way for carrying our invention into effect but it is to be
understood that our said invention is not limited to the precise details illustrated.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is
1. In automatic locks for dark slides, the employment of means for automatically
locking the shutter after exposure, substantially as hereinbefore described and
illustrated in accompanying drawings.
.
2. The formation of incline on loose arm or bolt E at an angle suitable for a
guide, to direct the pin or screw A. into the slot which acts as a lock to the shutter
as hereinbefore described and illustrated in accompanying drawings.
3. The combination and arrangement of parts forming the automatic lock for
photographic dark slides as herein before described and illustrated in the
accompanying drawings.
W. F. FLETCHER.
E. J. B. DANKS.