IMPROVEMENTS IN INSTANTANEOUS SHUTTERS FOR PHOTOGRAPHIC PURPOSES
Year: 1885

page_text: I, GEORGE SYLVESTER GRIMSTON of N° 3 Mycenae Villas, Mycenae Road,
Westcombe Park, Greenwich S.E. in the County of Kent, Engineer. do hereby
declare the nature of my invention for IMPROVEMENTS IN INSTANTANEOUS
SHUTTERS FOR PHOTOGRAPHIC PURPOSES to be as follows:-
My invention relates to Improvements in Instantaneous Shutters for Photographic
purposes, and has for its object the construction of an instantaneous Shutter in
such a manner that the ordinary diaphragm slit in photographic lenses can be used
for inserting the said shutter, no alteration or cutting of the original lens mounting
being required.
In order to attain this object I construct the instrument with a sliding plate or
shutter and a case to contain and guide it, these are made of such thin material
that they will fit into the slit used for the ordinary diaphragms, as for instance
those of the "Waterhouse" type.
That portion of the said case which enters the diaphragm slit is pierced with a
hole, which will correspond to the hole in the ordinary diaphragm, this hole
(when the apparatus is in use) being rapidly opened and closed by the said sliding
shutter.
That portion of the case which projects outside the diaphragm slit has attached
to it a mechanical device for rapidly lifting and depressing the sliding shutter, thus
opening and closing the hole.
This device is preferably a small crank, actuated by an adjustable spring
enclosed in a protecting case, the crank pin being directly connected to the said
sliding shutter.
In use this crank is held by a catch (the said spring being in tension) and
the sliding shutter being in such a position that the hole corresponding to the
diaphragm hole is closed. Upon the crank being released from the catch it makes

page_text: one revolution, thus lifting and depressing the said shutter, stopping against a stud
provided for the purpose. The rapidity of this operation being controlled by the
degree of tension of the spring.
I preferably cause the catch to be actuated by a pneumatic releasing apparatus,
such apparatus may, consist of a small cylinder and piston, the air to work it
being conveyed by a flexible tube connected to a hollow ball to be compressed by
the hand.
I do not limit myself to the arrangement of crank and spring for actuating the
said shutter, any device for attaining the same end may be used, as for instance a
pneumatic cylinder.

page_text: COMPLETE SPECIFICATION.
!
Improvements in Instantaneous Shutters for Photographic
Purposes.
I GEORGE SYLVESTER GRIMSTON of No 3 Mycenae Villas, Mycenae Road,
Westcombe Park, Greenwich, S.E. in the County of Kent, Engineer, do hereby
declare the nature of my invention for IMPROVEMENTS IN INSTANTANEOUS
SHUTTERS FOR PHOTOGRAPHIC PURPOSES 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 Instantaneous Shutters for Photographic
purposes, and has for its object the construction of an Instantaneous Shutter in
such a manner that the ordinary diaphragm slit in photographic lenses can be used
for inserting the said shutter, no alteration or cutting of the original lens mounting
being required.
In order to attain this object I construct the instrument with a sliding plate or
shutter and preferably a case to contain and guide it, these are made of such thin
material that they will fit into the slit used for inserting the ordinary diaphragins,
as for instance those of the "Waterhouse" type.
One mode of carrying my invention into practice is illustrated by way of
example in the accompanying drawing, in which
Fig. 1. represents a front elevation of an Instantaneous Shutter constructed
according to my invention.
Fig. 2. is a side elevation of the same, with the pump removed for greater
clearness.
The letters of reference are the same in both figures.
a is a sliding shutter and b is a case which guides it, these are made of such thin
material that they will fit into the slit used for inserting the ordinary diaphragms
in photographic lenses, as for instance those of the "Waterhouse" type.
That portion of the said case b which enters the diaphragm slit is pierced with
a hole c which will correspond to the hole in the ordinary diaphragm, this hole
(when the apparatus is in use) being rapidly opened and closed by the said sliding
shutter a.
The case 6 can be made interchangeable so that if a different opening c
is required a case with the desired opening can be used. That portion of the case b
which projects outside the diaphragm slit is made so that it will entirely cover the
said slit when the shutter is inserted in the lens tube, and has attached to it a
mechanical device for rapidly lifting and depressing the sliding shutter a, thus
opening and closing the hole c. This device is preferably a small crank d, actuated
by an adjustable spring enclosed in a protecting case e, the crank pin f being
directly connected to the said sliding shutter a, and in order to connect the crank
directly to the sliding shutter (without the. intervention of a separate connecting
rod, slot in the sliding shutter a or any similar device) I construct the lower portion
of the sliding shutter a as shewn, so that the angular motion caused by the crank
will not interfere with its up and down motion in the case b.

page_text: :
In use the crank is held by a catch g (the said spring being in tension) and the
sliding shutter a being in such a position that the hole c corresponding to the
diaphragm bole is closed, upon the crank being released from the catch g it makes
one revolution, thus lifting and depressing the said shutter a, stopping against a
spring stud h provided for the purpose, the rapidity of this operation being
controlled by the degree of tension of the spring in the case e. But I do not limit
myself to the adjustable spring. for controlling the rapidity of the working of the
shutter, any device for attaining this end may be used, as for instance an air pump
or brake, consisting of a small cylinder and piston worked from the other end of
the crank spindle, so as to retard the crank when at its highest position.
I preferably cause the catch ġ to be actuated by a pneumatic releasing apparatus,
such apparatus may consist of a small cylinder or pump and piston i, the air to
work it being conveyed by a flexible tube k connected to a hollow ball to be
compressed by the hand.
5
.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
n
1st. The construction of an instantaneous or time shutter for photographic
purposes so that it will fit into the ordinary diaphragm slit in photographic lenses,
such slit being that used for inserting ordinary diaphragms as for instance those of
the "Waterhouse" type, without in any way cutting or altering the original lens
mounting.
1
2nd The utilisation of the ordinary diaphragm slit in photographic lenses for
inserting an instantaneous or time shutter, such slit being that used for inserting
ordinary diaphragms as for instance those of the "Waterhouse" type, without in
any way cutting or altering the original lens mounting.
3rd In instantaneous or time shutters for photographic purposes the construction
and combination of a crank and sliding shutter as described and shewn by the
accompanying drawings, so that the crank can be directly connected to the sliding
shutter without the intervention of a separate connecting rod, slot in the sliding
shutter, or similar device.
4th My instantaneous shutter as described and shown by the accompanying
drawings.