Year: 1886

page_text: Date of Application, 8th Nov., 1886.
Complete Left, 27th Apr., 1887.
Complete Accepted, 27th May, 1887.
RESE
JOHN THOMAS MAYFIELD, and JOSEPH TORR TODMAN, both of 41 Queen Victoria
Street, in the city of London, Electricians do hereby declare the nature of this
invention to be as follows:-
Our Invention consists in an improved photographic shutter, and method of actuating
the saine, and is carried out as follows. A piece of metal tube is selected of suitable
size to fit the nose of the Camera lens, to which it is fastened by screwing, or in any
other manner.
A diaphragm is fitted inside this piece of tube, the hole in its centre being of
sufficient area to admit the requisite amount of light. Upon the front side of the
diaphragm are fastened two strips, so formed as to provide a channel in which the
shutter can slide freely. The shutter consists of a piece of metal sufficiently long to
cover the hole in the diaghragm when in its normal position; the lower end of the
shutter is perforated; the hole being of the same area as that in the diaphragm, and to
the bottom of the shutter is fastened a piece of wire which terminates in a small
plunger, or piston, sliding freely in a cylinder formed of metal tubo, which cylinder
is fastened to the exterior of the ring fitted to the nose of the lens at one end, but is
open at the other end; so that an india rubber tube terminating in a ball may be
attached to it, this ball being filled with air, or other fluid capable of operating the
piston when pressure is exerted upon it.
The action is as follows-
The metal ring being adjusted to the lens in the manner described, the shutter will
cover the hole in the diaphragm through which the light is admitted. Upon pressing
the ball containing the air, or other fluid, the piston carrying the shutter will be
driven upwards; and light admitted through the hole in its lower end.
By maintaining the pressure any duration of exposure can be obtained; and upon
releasing the pressure the expansion of the ball sucks back the piston, and the shutter
returns to its normal position. To avoid shock, the shutter is made in rising to strike
against a small india rubber buffer, which is fastened by a screw, or by other means,
to the top of the ring immediately above it.

page_text: employed.
Fig. 8, Plan of same.
Fig. 9, General view of camera, with shutter in working position.
Fig. 10, Section of piston sometimes employed with arrangement shewn in Fig. 1.
A piece of metal tube or ring a, Fig. 1 and Fig. 9, is selected of suitable size to
fit the nose of the camera lens a, to which it is fastened by screwing, or in any other
manner.
A diaphragm b, is fitted inside this piece of tube, the hole in its centre c, being of
sufficient area to admit the requisite amount of light. Upon the front side of the
diaphragm b, are fastened two strips e e, so formed as to provide a channel in which
the shutter, can slide freely, see section on line Y Z, Fig. 3.
The shutter, consists of a piece of metal sufficiently long to cover the hole in
the diaphragm b, when in its normal position, the lower end of the shutter f, is
perforated the hole being of the same area as that in the diaphragın b, and to the
bottom of the shutter is fastened a piece of wire g, which terminates in a small
plunger, or piston h, see Fig. 10, sliding freely in a cylinder i, formed of metal tube
which cylinder is preferably fastened to the exterior of the tube, or ring a, fitted to
nose of lens, at one end, but is open at the other end, so that an india rubber tube,
terminating in a ball, or other shaped compressor J, may be attached to it; this ball,

page_text: or other shaped compressor being filled with any fluid capable of operating the
plunger, or piston h, when pressure is exerted upon it. We prefer however to fill
the compressor with water, oil, glycerine, or other fluid having similar characteristics.
The action is as follows.
The metal tube, or ring a, being adjusted to the lens æ, see Fig. 9. in the manner
described the shutter f, will cover the hole in the centre of the diaphragm b, through
which the light is admitted.
Sometimes we prefer to mount the ring a, containing the shutter, between the
glasses forming the lens.
Upon pressing the ball, or other shaped compressor J, containing the suitable fluid
as described, the plunger or piston 4, carrying tho shutter f, will be driven upwards,
and light admitted to the lens, through the hole in its lower end. By maintaining tho
pressure any duration of exposure can be obtained; and upon releasing the pressure
the expansion of the ball sucks back the piston, or plunger, and the shutter returns to
its normal position.
To avoid shock the shutter is made in rising to strike against a small indiarubber
buffer m, which is fastened by a screw, or by other means to the top of the tube,
or ring a.
Fig. 4. Is a modification of our improved photographic shutter; in which the
cylinder i, containing the plunger or piston h, which by means of the wire 9, actuates
the shutter, is fastened to the side of the tube or ring a, screwed or otherwise
fastened to the nose of the camera, the holo or aperture c, is here shown open: we
sometimes employ a piece of tube 4, in placo of the solid plunger or piston, so fitted
as to prevent the escape of any fluid employed, but having perfectly free motion
within the cylinder i, to which the tube and condensor J, aro fastened as already
described for Fig. 1.
Upon compressing the hall or other shaped compressing vessel J, the tube or plunger,
is driven upwards and light admitted; and upon releasing the pressure the shutter f
Talls, closing the aperaturo c, see also section Fig. 6.
Fig. 5, Is a side view of cylinder i, plunger, and wire g..
Fig. 6, A vertical section upon line A B Fig. 4, shewing the position of the shutter
when the aperature c, is closed.
Fig. 7, Shews a vertical section of a form of plunger, or piston, having cup
leathers k. k, fitted on both sides of the piston h, having vent holo n,.for permitting
the escape of air or fluid. We find this most effective when the compressor is charged
with water, oil, glycerine, or other similar fluid, the packing always remaining tight,
and preventing its escape.
Fig. Plan of cylinder showing vent holo n.
Fig. 10, Shews another form of plunger, or piston, we sometimes employ, it can
be made of brass or other suitable substance; and if desired the groove l, can be
packed.
Having now particularly described, and ascertained, the nature of our said invention,
and in what manner the same is to be performed, we would wish it understood that
we are aware that shutters have been made actuated by levers, catches, and locking
gear, for the purpose of obtaining photographic portraits, or pictures, but to these we
fay no claim; neither do we confine ourselves in carrying our our invention to the
exact detail described and shewn, as such may be varied without deparnig from its
essential features. What we believe to be novel, and desire to secure by Letters
Patent is:
--
1st. A direct-acting sliding shutter for photographic purposes, consisting of shee
or ring a, mounted in any suitable manner upon the nose of the camera, cylinder i,
plunger, or piston h, working in same, the rod g, fastened to shutter f, buffer m, tho
shutter, being forced upwards or downwards by compressing the vessel J, which is
filled with any fluid suitable for actuating the piston or plunger h, substantially as
described for Fig. 1 and heroin set forth.

page_text: 2nd. The combination in a sliding shutter for photographic purposes shewn in
Fig. 4, consisting of ring, or tube a, screwed or otherwise suitably constructed for
fastening to the nose of camera lens, or between the two or more glasses forming the
lens, or to the tube carrying the lens; the cylinder i, being fastened to either side of
said ring or tube, its lower end being fastened to the compressing vessel which is
filled with any suitable fluid, with water, oil, or glycerine for actuating the plunger or
piston, the particular form of tube, plunger or piston h, and wire g, attached to the
top of shutter, all combined and operating together for the purposes set forth.
3rd. The combination in a sliding shutter for photographic purposes, of the
cylinder, having piston or plunger h, fitted with cupleathers k, k and vent hole n,
in cap; all combined and operating together for admitting and closing the aperture c,
by means of the sliding shutter f.