Year: 1886

page_text: Date of Application, 27th May, 1886.
Complete Left, 17th Feb., 1887.
Complete Accepted, 18th Mar., 1887.
BESEDVE
I ARTHUR SAMUEL NEWMAN of 87 Evershot Road Finsbury Park in the County of
Middlesex Electrician do hereby declare the nature of this invention to be as
follows
1
My invention relates to improvements in the means and apparatus employed for
opening and closing photographic shutters and in regulating the time of exposure of
the photographic plate or surface on which the image is cast.
According to my improvements the time of exposure can be varied from the fraction
of a second to a few seconds or for any time according to the will of the operator.
For this purpose in carrying out my invention the shutter (which may be of the
ordinary kind used for rapid work) is connected to a loosely fitting piston moving up
and down in a metal cylinder into which the air enters and the time of exposure is
governed by the rate at which the air is forced out and re-enters the cylinder. This
is effected by means of a series of perforations of graduated size in the top of the
cylinder over which a cover revolves so as to cover or to expose the whole or only a part
of such perforations, the larger the extent of the perforations exposed the more rapid
is the action of the shutter and the shorter the exposure.
A slot or aperture of graduated size may be cut in the top of the cylinder in place
of a series of holes.
The actuating mechanism consists of a convolute wire spring or watch spring which
is wound up by an axis or stud on the frame of the shutter one end of the spring being
attached to the rotating stud and the other to the fixed plate or frame. A bar is
fixed on the end of the rotating stud one end of the bar being connected by a link or
rod to the piston and by which it is moved up and down in the cylinder when the stud
is turned. When the stud is turned half a revolution a projection on the end of the
arm engages with a catch on the letting off lever and retains the shutter wide open for
focusing another half revolution acting to close the shutter again the spring at the
same time being wound up and retained by a projection on the other end of the bar
engaging with the same lever catch as before.

page_text: When it is desired to give an open exposure all or nearly all of the apertures are
closed the shutter is raised and retained by the catch until released at the will of the
operator.
It will thus be seen that the time of exposure can be regulated to any period
required and repeated any number of times or at any interval and can be set again
after other periods of exposure have been used, the resulting speed being always the
same, with the same setting.
The shutter may be arranged to act in the diaphragm slot without alteration to lens
in any way.
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Photographic Shutters.
I, ARTHUR SAMUEL NEWMAN of 87 Evershot Road Finsbury Park in the County
of Middlesex Electrician 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:-
My Invention relates to improvements in the means and apparatus employed for
opening and closing photographic shutters and in regulating the time of exposure of 2
the photographic plate or surface on which the image is cast."
According to my improvements the time of exposure can be varied from the fraction
of a second to a few seconds or for any time required according to the will of the
operator.
For this purpose in carrying out my invention the shutter (which may be of the 2
ordinary kind used for rapid work) is connected to a loosely fitting piston moving up
and down in a metal cylinder into which the air enters and the time of exposure is
governed by the rate at which the air is forced out and re-enters the cylinder. This
is effected by means of perforations of graduated size in the top of the cylinder over
which a cover revolves so as to cover or to expose the whole or only a part of such
perforations, the larger the extent of the perforations exposed the more rapid is the
action of the shutter and the shorter the exposure.
A slot or aperture of graduated size may be cut in the top of the cylinder in place
of a series of holes.

page_text: step or catch on the letting off lever fin order to retain the shutter wide open whilst
focusing another half revolution acting to close the shutter again the spring e' being
wound up and retained by a projection on the other end of the bar es engaging with
the catch on the lever as before. One end of the lever is connected by a pin joint
to the casing of the apparatus the other end passing through a slot into a recess in the
piston which moves up and down in the tube g' to which an elastic tube and hollow
bulb is attached which on being compressed by the hand of the operator causes the
pressure of air to raise the piston g and with it the end of the lover to release the
end of the lover arm e³ from the catch on the lever f the reaction of the spring e¹
thus raising and lowering the piston' a² and shutter a quickly or slowly as previously
described.
g
his a hinged lever and spring clip to fix and secure the shutter and apparatus on to
the lens tube the shutter acting in the diaphragm slot the guide ring i keeping the
apparatus in its proper position. For some purposes the position of the shutter a and
apparatus combined therewith is reversed as shown by Figure 8 the arrangement of
the letting off lever being modified to suit this arrangement which will be readily
understood as all the parts are marked with corresponding letters of reforence to those
previously described.
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 improved arrangement and combination of mechanism for raising and
lowering the shutters of photographic cameras automatically substantially in the
manner and for the purpose hereinbefore described and represented in the drawings
hereto annexed.
2. I claim the improved means and apparatus employed for regulating and governing
the time of exposure and the discharge of the air from the cylinder b, and its entrance
thereto substantially in the manner hereinbefore described and represented in the
drawings hereto annexed.
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Patentee.