Improvements in or relating to Photographic Roller Blind Shutters or the like.
Year: 1895

page_text: Date of Application, 8th Apr., 1895
Complete Specification Left, 8th Feb., 1896-Accepted, 4th Apr., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Photographic Roller Blind Shutters
or the like.
JOHN BELL IRVING Blackhall House near Carlisle Gentleman do hereby
declare the nature of this invention to be as follows:-.
This invention constitutes an improvement or improvements in photographic
roller blind shutters or the like. Its effect is that on winding up the shutter by
drawing a cord or the like instead of the cord being left projecting until the shutter
is released so as to risk impeding the accurate working of the shutter the cord
withdraws immediately to its original position; also that the manipulation of the
shutter from the face or back is easily accomplished. The bobbin or piece on
which the setting cord is wound is made free from the tube or roller on which the
The bobbin is
blind is wound acting upon it only while the blind is being set.
attached directly or indirectly to a spring or the like which rewinds the cord when
released. A cord may be employed for altering the tension of the main spring of
the shutter. Catches or the like may be worked from the face or back for holding
& releasing the various parts.
Dated this Second day of April 1895
Figure 5, a back elevation; anu
Figures 6 and 7, detail views.
In these, A is the box or frame in which the rollers or barrels B and C are
mounted having holes a the size of the lens cut in the front and back thereof. In
he drawings, the front is removed for clearness. The bobbin or pulley D on
which the setting cord d is wound is made separate from the barrel B on which the

page_text: blind is wound, the said bobbin acting upon it only while the blind is being set.
As shown clearly in the drawings, the bobbin D is provided with teeth d¹ which
are adapted to engage with teeth 6 on the end of the barrel B but is normally held
from engagement therewith by spring E. A spring F which for convenience is
placed inside the blind roller B but has no connection with the blind, operates to
rewind the setting.cord d on the bobbin D, and for this purpose is fixed at one end
to a collar F on the spindle F, its other end being attached to a fixed lug G.
The bobbin D is fixed on the spindle F. H is a disc on the end of spindle F
having inclined projections f which on the rotation of the bobbin D engage with
similar projections f¹ fixed to the framework, thereby causing the bobbin to
engage with the barrel B and to rotate the same. I is a toothed wheel on the end
of the barrel B and J a spring pawl engaging therewith. K is a push rod which
when pressed upwards disengages the pawl J from the barrel B, thereby freeing
the latter and making the exposure, but it will be obvious that various other
mechanical devices may be substituted for this. Referring to the barrel C, L is
the main spring of the shutter, one end of such spring being fixed to the barrel at 1,
its other end being fixed to the bobbin or pulley M, and N is a cord wound round
the latter and passing through a hole n to the outside, which cord serves for
regulating the tension of the main spring. O is an ordinary spring pawl device for
retaining the spring in tension and P an arm for raising the pawl so as to reduce or
take off the tension.
The mode of action is as follows:-
To set the blind, the cord d which operates the top winding bobbin B and passes
through an arm of the disc H and through the frame to the outside as shown, is
pulled, thereby causing the bobbin D to rotate, and also the projections on the
disc H to engage with the fixed projections f¹, thus pressing the winding bobbin
inwards, causing it to engage with the barrel B and to rotate it. When the
winding is completed, the cord is released and the bobbin under the action of the
spring F returns to its original position and rewinds the cord while at the same
time the blind remains set, the disengagement being brought about by the inclined
projections returning to their normal positions and the spring F which always
tends to force the bobbin outwards.
The shutter being now ready for work, the push rod K which is on the outside
of the frame as shown is pressed upwards and raises the spring pawl J, thereby
freeing the barrel B on which the blind is wound. The latter is then drawn down
by the action of the main spring 'L and the exposure is made, the time of exposure
of course corresponding to the amount of tension given to the main spring by
means of the cord N. It will be observed that the mechanism for holding or
releasing the various parts can be worked from the face or back of the apparatus
and the winding up cord always returns to its wound up position as shown in
Figure 3, so as not to interfere with the accurate working of the shutter which is
the main feature of the invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
::
1. The improvements in or relating to photographic roller blind shutters or the
like, which consists in forming the winding bobbin separate from the roller on
which the blind is wound, but capable of engagement therewith for the purpose
of winding or setting the blind, such bobbin on the completion of the winding or
setting returning to its original position, thus rewinding the cord or the like on
the bobbin, so as not to interfere with the working of the shutter, while the blind
remains set or in its wound up position substantially as described.
2. In connection with a roller blind shutter such as described, the means whereby
the tension of the main spring of the shutter may be regulated and the holding and
releasing of the various parts accomplished from the outside of the box or casing
of the shutter.
.

page_text: 3. The general construction and arrangement of parts of the improved roller
blind shutter, substantially as and for the purposes described.
Dated this 7th day of February 1896.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Birmingham, and London, Patent Agents.