An Improved Shutter for Photographic Cameras.
Year: 1894

page_text: Date of Application, 25th July, 1894-Accepted, 1st Sept. 1894
COMPLETE SPECIFICATION
An Improved Shutter for Photographic Cameras.
I, DAVID MORGAN, of 76, Broad Quay, Bristol, Gas Fitter 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, which relates to shutters for photographic cameras, consists in the
provision in one continuous or endless piece, of an exposing and safety blind
arranged to run over rollers fitted to rotate in the shutter box towards the top and
bottom thereof respectively. The blind is composed of opaque flexible material
usually employed in photographic shutter blinds, as, for example, black macintosh.
It has two apertures by means of which, when the blind is adjusted or set with
that object, light is afforded unobstructed access to the camera lens. Similarly,
when the shutter is closed the blind affords a two-fold shield against the penetration
of light.
Towards each end of the lower roller, which is a spring roller, is attached a
cord, preferably of silk. One end of each cord is, after attachment, wound once
(or, if need be, twice) round the roller and is then carried up over the upper roller.
The other end of each cord is carried up from the opposite side of the lower
roller to meet the end conducted, as aforesaid, over the upper roller. The two
ends thus meeting are tied or otherwise connected together and are attached to the
blind.
Accordingly the blind being thus connected to the lower roller moves with
it in one direction when setting for focussing or exposure and with it also in the
reverse direction when released. A notched disc and spring trigger pawl are
adopted for retaining the blind when set, and the usual pneumatic ball and tube are
employed for release.
The shutter is arranged for making both "instantaneous" and "time"
exposures.
In the accompanying sheet of illustrative drawings,
Fig. 1 represents a view of my improved shutter as removed from the shutter
box and as seen from behind. The blind is shown as set for focussing. A piece
of the blind is removed at each side to shew the attachment of the cords to the
lower roller.
Fig. 2 is a central vertical section.
The blind a is a continuous or endless piece of opaque and flexible material
such as is usually adopted for shutter blinds, as, for example, black macintosh.
The blind a, which has two apertures a¹ oppositely situated, is extended over
a roller 6 at bottom and a roller c at top; both carried in bearings in side
plates d, d'.
The roller b, which is tubular and is preferably covered with india-rubber or like
substance, contains within it a spindle 6' about which is coiled a spring b² one end
of which engages with a slot in the tube, and the other end of which is attached
to the spindle. Firmly fixed to one end of the roller b, which is shewn in section
at Fig. 3, is a pinion e gearing with a stop wheelf loosely centred on the pin fl
fixed in the plate d¹. The blind setting handle e¹ is firmly connected to the pinione.
The handle e, pinion e and roller b rotate together.
Towards each end of the roller 6 there is attached thereto a cord g, preferably
of silk. Attachment of the cords g to the roller 6 may be made by passing the

page_text: cords through the india-rubber covering or by tying the cords around the roller. One
end of each cord g is, after attachment of the cord to the roller b, wound once (or,
if need be, twice) round the latter and then carried up and conducted over the
roller c.
The other end of each cord 9 is carried up from the opposite side of the
roller 6 to meet the end conducted, as aforesaid, over the roller c. The two ends
thus meeting aro tied or otherwise connected together and are attached to the
blind a as at g', Figs. 1 and 2. The blind a being thus connected to the roller b
and sufficient length of cord being provided to allow full play of the blind, the
latter moves over the two rollers b and c when the former is rotated either by the
handle e¹ in setting, or by the spring in closing the shutter.
The cords g are preferably passed through the blind so as to allow the blind to
lie below them at the upper roller c, as shewn.
To set the blind a, the handle e' is turned in the proper direction and the blind
is thereby raised at front to the required extent either for focussing or exposure.
It is retained in the position to which it is set by the spring trigger h pivotted at h
to the side plate and engaging at foot with notches provided for it at suitable
intervals in the rim of the notched disc i fixed on the setting handle e¹.
the blind a is set for exposure, light is excluded from the lens by the blind both at
front and back. The blind consequently constitutes a double screen against
penetration of the light.
When
The blind is released and closed by means of the usual pneumatic ball ; and
tube j.
At Fig. 4 is shewn an end view of the shutter frame, and the blind restraining
and releasing apparatus. At Fig. 5 is shown the stop-wheel for controlling the
setting and closing of the blind. On the ball ; being squeezed, as is well under-
stood, the trigger is moved out of engagement with the particular notch in the
disc at which it was set. The blind a then returns to the normal position at a
speed depending on the tension of the spring b². In this way "instantaneous
exposures are made.
"
c
The blind, in closing, is prevented from moving beyond the requisite extent for
closing by the stop-wheel which is furnished with a stop-tooth which, when
the blind is closed after exposure, comes into contact with a tooth of the pinion
and prevents further rotation of the roller b in the direction for closing the
shutter. Similarly, the stop wheel controls the extent to which the blind can be
raised.
The tension of the spring 62, which is always sufficient to work the blind, is
increased at will, and the interval of exposure is shortened by winding the button
or knob k which rotates a pinion centred on the spindle b and gearing with the
toothed wheel on which is provided a stop tooth which, after contact with the
pinion as the blind closes, prevents the wheel from rotating further in the direction
for closing the shutter. By numerals, engraved or otherwise made to appear
on the speed indicator plate m, the duration of "instantaneous exposures is
shown.
"
The speed indicator and tension regulator does not constitute a part of my
invention; such devices being usual in photographic shutters.
The shutter is adapted for making time exposures. For this purpose a shelf n
is provided on the shaft of the setting handle e', as shown at Figs. 4 and 7 of
bich the latter is a view opposite to the view shown at Fig. 1. When it is
desired to make a time exposure the trigger h is first moved on its pivot so that its
foot is brought nearer the shaft of the setting handle e' than is required for
instantaneous exposures. When the ball; is squeezed, the trigger foot engages
with the top of the shelf n and arrests the blind when the apertures a¹ therein are
opposite the lens. The blind remains in this position as long as the squeezing of
the ball is maintained. Relaxation of pressure on the ball allows the trigger h to
rebound towards the plate d² clear of the shelf n. The shutter then closes.
For time exposures the tension of the spring of the roller b should be at the
minimum.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a photographic camera shutter, a blind constituting, in one endless or
continuous piece of black macintosh or other suitably opaque and flexible material,
an exposing and safety blind and so arranged as to afford when set as for exposure
a double or two-fold shield for exclusion of light from the lens.
2. In a photographic camera shutter, a continuous or endless blind such as a with
apertures a¹ oppositely placed; said blind being passed at top over a roller such as c
and secured by cords such as 9 (or the equivalents thereof) to a
spring roller
such as b about which latter roller the said cords are wound and below which roller
the blind is passed; the arrangement being such that the blind moves as the spring
roller is rotated, substantially as hereinbefore described with reference to the
accompanying sheet of illustrative drawings.
3. In conjunction with a photographic camera shutter, means for retaining the
blind to any position at which it is set; said means consisting of a notched disc
such as rigidly secured upon the axis of the spring roller b, and spring trigger h
pivotted to the shutter frame and adapted to engage with the said notched
disc, substantially as hereinbefore described with reference to the appended
drawings.
4. In connection with a photographic camera shutter, means for governing the
range of travel of the blind; said means consisting of the stop wheel f, with
stop tooth f, gearing with a pinion such as e fixed on the axis of the spring roller b,
as herein before set forth and shown in the accompanying drawings.
5. The provision in the shaft of the blind setting handle, of a ledge such as n
for engagement with the foot of the spring trigger when the latter is so moved
on its pivot as to cause the trigger foot to approach sufficiently near the said shaft
of the blind setting handle, and thus to cause arrest of the blind for making "time
exposures, as hereinbefore set forth.
Dated this 24th day of July 1894.
"
NICHOLAS WATTS,
Chartered Patent Agent, Bristol.