An Improvement in the Mechanism of Photographic Roller Blind Shutters for Obtaining both Time and Instantaneous Exposures.
Year: 1897

page_text: Date of Application, 10th Nov., 1897
Complete Specification Left, 10th Aug., 1898-Accepted, 22nd Oct., 1898
An Improvement in the Mechanism of Photographic Roller Blind
Shutters for Obtaining both Time and Instantaneous Exposures.
I, BENJAMIN WILLIAM HORTON, of Cold Harbour House, near Hythe, Kent,
Photographic Apparatus Maker, do hereby declare the nature of this invention to be
as follows
The object of my invention is to reduce the size and weight of a photo shutter and
at the same time to allow a liberal length of slot in the roller blind.
In order to make shutters compact and at the same time to allow a sufficiently
long slot in the blind, it is found necessary to make five or more coils of blind on
each roller. This does not affect the bottom or working roller containing the spring,
but the question arises how to allow the blind to unwind off the top or release roller
until the slot in the blind allows full aperture, and to hold it thus as long as required
for time exposures, and then by relaxing the pneumatic ball to allow the blind to
finish its unwinding and close the aperture.
In my improved shutter I propose to use a similar action of pneumatic release to
that in the well known Thornton Pickard shutter, that is to say press the ball to
release, and in the time exposure by relaxing the pressure on the ball, allowing the
aperture to close.
I also propose to change the shutter from time to instantaneous or vice versa by
moving a pointer similar to the above.
In my invention I fix to the end of release roller a disc having an annular groove
hereafter called the starting groove, on its face near its periphery, and running from
this groove I propose to have a spiral groove running towards the centre of the disc,
either terminating at its centre or after making the necessary number of turns to
run into another annular groove nearer the centre. The starting groove need not
necessarily be near the outer edge, the above order might be reversed; or to produce
exactly the same effect I could run the starting groove round a cylinder, connecting
it with a square thread screw of the desired length or terminating in another
circular groove.
I propose to have a release lever carrying a projection, hereafter called the runner,
fitting freely in the above grooves; I could also have a spring which would have a
tendency to keep the runner either in the starting groove or to guide it into
the spiral groove or thread, according to how it was previously set to an index. In
the starting groove I have a stud fixed to catch bottoin of runner when at its normal
depth in the groove, but from which it would escape when raised slightly in the
groove. I also have a second stud or stop over the spiral or thread, so arranged
that the release lever would catch it when raised as above, but would escape when
in its normal position. Or a stop might be fixed independent of the disc or cylinder
and so arranged as to arrest the lever as the runner causes it to travel along
and check the disc. In either case the second stop must be as many turns of
disc from the first one as will allow the slot in blind to uncover the aperture.
The action of working is as follows: the shutter being "set" the blind wound on
the release roller, the runner is in the starting groove and catches the stop and

page_text: prevents unwinding. Supposing an instantaneous exposure is required, the spring
inust be set so as to keep runner in starting groove, to set it off press the pneumatic
ball which will raise runner above the stud, and allow the roller to revolve until all
the bind is unwound. For time exposure: the spring must be set so as to press
runner toward the spiral or thread; then by pressing the ball as before, the roller will
revolve, the runner entering and travelling along the spiral or thread until arrested
by the second stop. Upon relaxing the ball the runner will fall into its normal
position, allowing the second stud to escape, the roller being set free again and the
aperture closed, the 'runner continuing its course in the remainder of the
groove.
Dated 16 10th day of Nwombo 1907
S. S. BROMHEAD,
Patent Agent, 171, Queen Victoria Street, London,
An Improvement in the Mechanism of Photographic Roller Blind
Shutters for Obtaining both Time and Instantaneous Exposures.
I, BENJAMIN WILLIAM HORTON, Cold Harbour House, near Hythe, Kent, Photo-
graphic Apparatus Maker, 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 object of my invention is to reduce the size and weight of a photo shutter
'and at the same to allow a liberal length of slot in the roller blind.
In order to make shutters compact and at the same time to allow a sufficient time
'for the slot in the blind it is found necessary to make five or more coils of blind on
each roller. This does not affect the bottom or working roller containing the spring,
but the question arises how to allow the blind to unwind off the top or release roller
until the slot in the blind allows full aperture, and to hold it thus as long as required
for time exposures, and then by relaxing the pneumatic ball to allow the blind to
finish its unwinding and close the aperture.
In my improved shutter I propose to use a similar action or pneumatic release to
that in the well known Thornton Pickard shutter, that is to say press the bail to
release and in the time exposure relax the pressure on the ball thereby allowing the
aperture to close.
I also propose to change the shutter from time to instantaneous or vice versû by
moving a pointer similar to that employed in the above.
In my invention I fix to the end of release roller a disc having an annular groove
hereafter called the starting groove, on its face near its periphery, and running
froin this groove I propose to have a spiral groove running towards the centre of the
disc, either terminating at its centre or after making the necessary number of turns
to run into another annular groove nearer the centre. The starting groove need not
necessarily be near the outer edge, the above order might be reversed or to produce
exactly the same effect I could run the starting groove round a cylinder, connecting
it with a square thread screw of the desired length or terminating in another circular
groove.
I propose to have a release lever carrying a projection, hereafter called the runner,
fitting freely in the above grooves; I could also have a spring which would have a
tendency to keep the runner either in the starting groove or to guide it into the
spiral groove or thread, according to how it was previously set to an index.
In the starting groove I have a stud or stop fixed so as to catch the bottom of
runner when at its normal depth in the groove, but from which it would escape when

page_text: raised slightly in the groove. I also have a second stud or stop over the spiral or
thread, so arranged that the release lever would catch it when raised as above, but
would escape when in its normal position. Or a stop might be fixed independent of
the disc or cylinder and so arranged as to arrest the lever as the runner causes it
to travel along and check the disc. In either case the second stop must be as
many turns of the disc from the first or as will allow the slot in the blind to
uncover the aperture.
The action or working is as follows:-
The shutter being "set" and the blind wound on the release roller, the runner is
in the starting groove and atches the stop and prevents unwinding.
Supposing an instants.eous exposure, is required the spring must be set so as to
keep the runner in starting groove, to release the disc and blind press the
pneumatic ball which will raise the runner above the stud, and allow the roller to
revolve until a one blind is unwound.
For time exposure: the spring must be set so as to press the runner towards the
spiral or thread; then by pressing the ball as before, the roller will revolve, the
runner entering and travelling along the spiral or thread until arrested by the second
or upper stop. Upon relaxing the ball the runner will fall into its normal position
allowing the second stud to pass, the roller being set free again and the aperture
closed, the-runner continuing its course in the remainder of the groove.
I will now describe my invention with reference to the accompanying drawings
in which
Fig. 1 shows a front elevation of the mechanism of the improved shutter.
Fig. 2, show a side elevation of Fig. 1.with cover removed so as to show
blind.
Fig. 3 shows an enlarged elevation of the release roller disc and shows also the
stop for instantaneous exposure.
Fig. 4 shows a section on line 1-2, Fig. 3; looking in the direction of the arrow.
Fig. 5 shows a side elevation. of release roller disc with release lever and runner in
the raised position in contact with the stop for time exposure.
The drawing shows..what is..called a "Behind. Lens Shutter," a is the casing
of the shutter, provided with a cover b in which is formed the usual lens hole.
The shutter contains the slotted blind b' wound on rollers at either end. The
roller c is a spring roller, and d is the release roller, rotated by the setting string e.
The spindle d¹ of the release roller is prolonged and projects outside the casing
and is supported by a bracket d². Attached to that part of the spindle d' pro-
jecting outside the casing is a shallow cup-like disc f, provided with an outer
ring forming the side and a spiral projection f2. By this means a groove which
I call the starting groove is formed and from this a spiral groove is projected
leading towards the centre of the release roller disc f. These grooves engage with a
runner projecting from a spring lever h fulcrumined at h¹ to a plate i attached
to the casing of the shutter. This plate i is arched as shown and beneath it is
placed the expanding end of a pneumatic tube ; provided at its other end with
the usual air bulb.
By this means the arched plate with lever hand runner g is caused to rise
and fall.
The under side of the arched plate i is provided with a projecting guide pin i¹
recessed in the casing of the shutter.
To obtain an instantaneous exposure the starting groove is provided with a stop k
and the lever h is caused to engage with the starting groove by means of the spring
arın 1, attached thereto, the other end of which is provided with a pin which
enters an orifice 12 in the plate i. Thus, when the blind b¹ is set by the setting
string e, the stop k prevents the rotation of the disc f attached to the release
roller d. But upon raising the plate i, lever h and runner by pressing the
pneumatic bulb the disc is released and the blind is unwound from the release
roller and is taken up by the spring roller c.
The slot in the blind as it travels
across the lens opening causes the exposure.

page_text: To obtain a time exposure the pin on the end of spring arm is caused to
enter the orifice 13 thus moving the lever h laterally so that the runner g will have
a tendency to pass into the inner or spiral groove made by the spiral projection f².
The blind is then set as above described. The stop k prevents the blind moving
until ready, and when the runner gis raised, the release roller is free and revolves,
until the corner of the lever h, which caused to travel towards the centre of
the disc by the spiral projection 2, stops tu rotation by contact with the stop m,
which projects from the spindle of the release roller d. In the meantime the slot
in the blind is brought opposite to the lens opening and held stationary. After
sufficient exposure the pneumatic bulb is then relad, which lowers the end of
lever out of contact with the stop m, and the blind is wound up.
o is an angular pin serving to keep the expanding end of the pneumatic tube in
place. p is a looped pin to keep the spring arm in place.
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. The improved photographic roller blind shutter substantially as shown and
described.
2. In an improved photographic roller blind shutter the discf with its ridges f¹, f²,
attached to the spindle d' of the release roller d, in combination with the stop k,
lever h, runner g, spring arm l, pin l, orifice 12 and arched plate i, for producing
an instantaneous exposure, substantially as shown and described.
3. In an improved photographic roller blind shutter, the combination of the
stop m projecting froin spindle d¹ and orifice 13, with the devices specified in
Claim 2 for producing a "time" exposure, substantially as shown and described.
Dated this 10th dow of Anunt 1000
S. S. BROMHEAD,
Patent Agent, 171, Queen Victoria Street, London.
S. S. BROMHEAD,
Patent Agent, 171, Queen Victoria Street, London.