Improvements in Camera Shutters used in Taking Photographs.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Camera Shutters used in Taking Photographs.
I, ROBERT MARTIN, of the Bazaar, Candleriggs Street, in the City of Glasgow,
Engineer, do hereby declare the nature of this invention to be as follows:-
The improvements which constitute my invention are specially adaptable to
what are known as rebounding shutters which in conjunction with photographic
cameras are used for taking photographs.
Besides the other possible parts which such shutters may comprehend, in the
commoner forms of rebounding shutters there are the body which fits on to the
camera lense & the shutter proper or moveable screen. When the screen is in
position, it excludes all light from the interior of the camera by resting in front
of the lense aperture in the body of the shutter. For the purpose of retaining
the moveable screen in this position there is a catch which may or may not be
withdrawn by means of a pneumatic arrangement. There are also two springs
or lengths of elastic for actuating the screen, one for displacing it & one for
replacing it. To set the shutter for giving an exposure, the displacing elastic
is stretched or distended & hooked on to a knob at the top of the screen. When
the catch retaining the screen is withdrawn, the displacing elastic draws the
screen away from in front of the lense aperture, making an exposure, & propells
the screen so that the knob on the screen comes against the replacing elastic
stretched across its path. Menanwhile the displacing elastic has disengaged from
the knob on the screen & the screen rebounds off the replacing elastic, back into
position, closing the aperture & completing an instantaneous exposure.
In my improved shutter hereinafter described, I employ as a means of opera-
tion, one pneumatic arrangement between the shutter & the hand of the operator.
The object of my invention is to effect improvements in what are known as
rebound or rebounding shutters, such similar camera shutters, by so con-
structing the shutter & its several parts that :-
--
First The shutter can be operated to give time exposures (as distinguished
from instantaneous exposures) as well as instantaneous exposures as distinguished
from time exposures.
Second-There is no difference between the setting of the shutter for a time
exposure & the setting of the shutter for an instantaneous exposure.
Third: When once the shutter has been set, either a time exposure or an
instantaneous exposure may be performed, as the operator may desire, according
to the manner in which the pneumatic ball is manipulated.
Fourth If the shutter has been set previously, the moveable screen will open
in answer to a slight compression of the ball & will not close again until the ball
has been compressed to its limit, thus making it unnecessary to sustain the com-
pression of the ball during the progress of time exposures.
Fifth If the the shutter has been previously set, by compressing the ball to
its limit the screen will open & shut instantaneously performing an instantaneous
exposure as in an ordinary rebounding shutter.
Sixth The Knob or point of application of the actuating elastics or springs is

page_text: at the bottom of the moveable screen instead of the top & the actuating elastics
or springs correspondingly lower allowing the body of the shutter to be cut off
much shorter, making a less clumsy & more compact instrument.
To accomplish the first, second, third, fourth & fifth aforesaid objects of my
invention, there are several modifications of the same principle which I may
employ.
I do not intend to confine or limit my claim to the one modification here-
inafter outlined but I merely describe it in illustration of the principle of my
invention because in my own opinion it has more to recommend it than the other
modifications.
In my improved shutter there are attached, two small springs of the long-flat
type & shape. The springs are fixed, the one being behind the other, on to and
parrallel with the back of the shutter & preferably behind one of the guides for
the screen.
The inner spring is set out from the back of the shutter to admit
of inserting the expansible balloon or tit of a simple pneumatic arrangement,
while the outer spring is set out still further to clear the working of the inner
spring. Both springs are reduced at the free ends & bent at right angles to pass
through a small hole in the body of the shutter, so that when the screen is shut,
the end of the inner spring projects through the body of the shutter just above
the top edge of the screen & the end of the outer spring presses lightly on the
screen just below the top edge. The end of the inner spring acts as a catch for
keeping the screen shut against the opening-strain of the actuating spring or
elastic & the end of the outer spring acts as a catch for keeping the screen open.
The springs are so adjusted that when the pneumatic ball is compressed to its
limit, both catches are withdrawn, & if the shutter has been previously set it acts
as an instantaneous shutter giving an instantaneous exposure. The catches,
however, are so set in relation to one another & to the screen that by a slight
compression of the pneumatic ball, the one catch only, which keeps the screen
shut, is withdrawn without withdrawing the other catch, so that when the screen
completely uncovers the lense aperture, the screen is caught by this latter catch
& detained in this open position as long as the operator may desire. Meanwhile
the pressure on the pneumatic ball may be relaxed or altogether removed, but
the screen will not close the lense aperture until by compressing the ball to its
limit, this latter detaining catch is withdrawn, the screen then closes by dropping
into position either because of its own weight or owing to the force exerted by
the aforementioned replacing elastic or spring.
Dated this Wounteanth der of Vavah 1900.
Improvements in Camera Shutters used in Taking Photographs.
I, ROBERT MARTIN, of the Bazaar, Candleriggs Street, Glasgow, Engineer, 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 improvements which I have effected, are in conjunction & connection with
what are known as rebounding or rebound shutters which are used with photo-
graphic cameras for making exposures in the taking of photographs. Such
rebound shutters are only capable of making instantaneous exposures without
the option of time exposures.
The object of my invention is to effect such improvements in the rebound shut-
ter, by so constructing it & its several parts that:

page_text: First. The shutter is capable of performing time exposures as well as instan-
taneous exposures.
Second. The shutter, before each exposure may be set in the same way as an
ordinary rebound shutter, by simply distending a stretch of elastic and hooking
it over a knob.
Third. The shutter may be operated by a pneumatic arrangement, consisting
of a compressible ball for the hand, connected by an air tube to an expansible tit
on the shutter.
Fourth. There is no difference between the setting of the shutter for a time
exposure, and the setting for an instantaneous exposure.
Fifth. After setting, the shutter may be operated to give a time exposure or
an instantaneous exposure according merely to the act of the operator.
Sixth. Time exposures may be protracted indefinitely, without necessitating
a sustained compression of the ball."
Referring to the accompanying sheet of drawings: Figures 1, 2, 3, 4, and 5
are respectively a side view, the front view, the plan, a section and the back view
of a common form of rebound shutter, embodying my improvements. Figures 6
and 7, are sections of modifications. In each figure similar letters refer to the
same individual part of the shutter. B. is a piece of wood forming the body of
the shutter and having a circular hole 0, cut through it in the lower end. A is
a piece of cork or other similar substance, fixed on to the body, and having a
hole, E, cut through to fit on to the front end of the camera lens Q. G, G, are
guides fixed on to the body. S, is a moveable screen fitted to slide freely up and
down in the guides. K, is a knob fixed into the screen. U, and L, are stretches
of an elastic band. P, is a screw passing through the front strip of one of the
guides and into the body. F, is a flat spring, fixed at the top end to the body
and reduced in width at the lower end, bent to a right angle, formin a catch C,
which passes through a free hole in the body and rests in a hole in the front strip
of the guide. T, is the expansible tit of a pneumatic arrangement, connected by
a flexible air tube to a compressible ball for the hand. H, is a cut taken out of
the screen, which is uniform in width, all its length, but varying in depth from
nothing at the bottom to about half the thickness of the screen at the top.
It will be seen that the elastic L, is so held as to intercept the knob. K, in its
path upwards, but the elastic U, is suspended so as to clear the knob in its motion
up or down. To set the shutter the elastic U, is distended and hooked on to the
knob. To operate the shutter for an instantaneous exposure, the air ball is
pressed to its limit and the following action takes place: The tit expands suffi-
ciently to withdraw the catch completely and the screen is immediately released,
and is consequently propelled upwards by the distended elastic U, which then
disengages with the knob. When the knob strikes against the elastic L, the
screen rebounds back into position, recovering the hole and terminating the
exposure instantaneously.
To operate the shutter for a time exposure. The shutter is set in the same way
as before. The air ball is just pressed sufficiently to release the screen, and the
following action takes place : The tit expands sufficiently to only partly with-
draw the catch. When the point of the catch has been withdrawn past the thin
edge of the screen, owing to the cutting H, the screen is released and rises, presses
the catch out till it passes it, the catch then slips in as far as the tit will allow
it, and holds the screen open as long as the operator may desire. It will be seen
that if the pressure on the ball is relaxed, the screen still remains un as the catch
only slips in further. To complete the exposure, the ball is compressed to its
limit & the screen drops down into position. In this case the elastics U, & L,
act in the same way as in an instantaneous exposure, the only difference is, that
when the screen rebounds from elastic L, it is caught & upheld by the catch until
the ball is pressed to its limit. In Figures 2 & 4 the lines dotted thus
show the position of the screen during the progress of time exposures.. Figures 6
&7 show two different modifications of the same principle as that shown in

page_text: Figure 4. These modifications differ only in construction, the method of setting
& operating being the same as before.
Referring to Figure 6: It will be seen that two spring catches similar to
spring F, are employed. The outer one is shown sprung out & pressing on the
screen, ready to slip in & keep it up when it rises. This outer spring only acts
in the case of time exposures. For instantaneous exposures & to terminate time
exposures, the increased deflection of the inner spring still further deflects the
outer spring & thus leaves a free passage for the screen to slide up or down.
Referring to Figure 7: The spring in this case terminates in a double catch,
the upper one to keep the screen shut as shown & the lower one to keep it open
as in the case of time exposures. To allow clearance for the catches a narrow
width of the screen is cut right out leaving only a small projecting part at the
top & bottom to engage with the catches. For instantaneous exposures or to
terminate time exposures, both catches are withdrawn clear of the screen.
for time exposures the upper catch only is withdrawn while owing to its extra
length the lower catch still projects. Consequently the bottom projecting part
of the screen, in the act of opening, has to press past it, thereafter rebounding
on to the top of it, where it rests until the exposure is terminated.
But
The screw P, as shewn acts in each case as a stop-pin upon which the screen
rests.
Having now particularly described & ascertained the nature of my said inven-
tion, & in what manner the same is to be performed, I declare that what I claim
is:-
1. The improved camera rebound shutter as herein before described & as illus-
trated by the accompanying sheet of drawings.
2. A camera rebound shutter which is capable of performing either time ex-
posures or instantaneous exposures, & in which there is no difference between
the setting for a time exposure & the setting for an instantaneous exposure.
3. The application of the pneumatic arrangement herein before described, to
operate the shutter only by compressions of the compressible ball & not by relax-
ations & to produce different results, depending upon the extent to which the
compressible ball is compressed.
Dated this 14th day of December 1899.