An Improved Instantaneous and Time Shutter for Photographic Lenses.
Year: 1891

page_text: Date of Application, 4th Aug., 1891
Complete Specification Left, 1st Apr., 1892-Accepted, 7th May, 1892
PROVISIONAL
SPECIFICATION.
An Improved Instantaneous and Time Shutter for Photographic
Lenses.
I, THOMAS FURNELL of 72, Lordship Lane East Dulwich London S.E. in the
County of Surrey, Civil Engineer, do hereby declare the nature of this invention
to be as follows:-
The shutter is formed of a combined lower metal sheath, and an upper metal
case; the lower sheath goes into the slot of the lens-tube and contains two thin
metal diaphragmatic slide plates of different forms, one passing over the other, and
forming an opening similar to the stop of the lens; but opening and closing in the
centre; these diaphragmatic plates are connected to, and actuated by, a balance-
rocker in the upper metal case above the lens-tube the balance-rocker causes one
plate to rise while the other is depressed; the balance-rocker is attached by a
connecting rod to a rocking metal-plate of suitable form having a curved slot up
its centre; this also is in the upper metal case above the lens-tube, and actuated by
a circular travelling disc running on a centre-pin fixed outside the front plate of
upper case, the disc in its circumference has a pin passing through the front plate
of upper case and actuates the rocking metal plate by means of the curved
slot above mentioned. The circular disc is actuated by a pneumatic cylinder con-
taining a partly spherical formed piston, which allows of a rocking motion without
loss of air force, the rod of 'which is attached by a screw pin to the above
mentioned travelling disc, a loose pawl being placed over the travelling disc, allows
it as required, to be stopped at full open of the diaphragmatic plates or to travel
on and open and close the diaphragmatic plates, at one pressure of the pneumatic
ball; and thus cause an instantaneous exposure. The pneumatic is the only motive
power used or required to work the shutter; and allows of any exposure, either
short, or prolonged, at the will of the operator.
It must be understood, that the details above mentioned may be modified,
without departing from the main features, or principles, of this invention.
Dated this 3rd day of August 1891
THOMAS FURNELL.
COMPLETE SPECIFICATION.
An Improved Instantaneous and Time Shutter for Photographic
Lenses.
I, THOMAS FURNELL of 72, Lordship Lane, East Dulwich London, S.E., in
the County of Surrey, Civil Engineer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :—
The shutter is formed of a combined lower metal sheath and an upper metal
case; the lower sheath goes into the slot of the lens-tube, and contains; two thin
metal diaphragmatic slide plates of different forms; one passing over the other,
and forming an opening similar to the stop of the lens, but opening and closing in
the centre; these diaphragmatic plates are connected to, and actuated by, a
balance-rocker, in the upper metal case above the lens-tube. The balance-rocker
causes one plate to rise, while the other is depressed; the balance-rocker is
attached by a connecting rod to a rocking metal plate of suitable form having a
curved slot up its centre, this also is in the upper metal case above the lens-tube,

page_text: and actuated by a circular travelling disc running on a centre-pin fixed outside the
front plate of upper case; the disc in its circumference has a pin passing through a
curved slot in the front plate of upper case and actuates the rocking metal plate
by means of the curved slot above mentioned; the circular disc is actuated by a
pneumatic cylinder, containing a partly spherical formed piston, which allows of a
rocking motion without loss of air force the rod of which is attached by a screw
pin to the above mentioned travelling disc. A loose pawl being placed over the
travelling disc allows it as required, to be stopped at full open of the diaphragmatic
plates, or to travel on and open and close the diaphragmatic plates at one pressure
of the pneumatic ball; and thus cause an instantaneous exposure; the pneumatic
is the only motive power used or required to work the shutter; and allows of
any exposure, either short or prolonged at the will of the operator.
It must be understood; the details above mentioned may be modified without
departing from the main features or principles of this invention;-for instance ;-
by slightly altering the form of rocking plate M, as shown in Fig. 5. of the
illustrations, altering the position of pneumatic cylinder, and adding a trigger W,
as shown in Fig. 6; the shutter can be operated with an elastic band Y; otherwise
all the details are identical with Figs. 1 to 4.-and by adding a short tube U, to
the back plate I, the shutter can be placed on the front of lens, as shown in
Fig. 9. and by adding two pieces of tube (one each side) the shutter can be
screwed into, or onto, the lens-mount, forming one body with the lens, as shown in
Fig. 10 of the illustrations, without in any way departing from the main features or
principles of this invention as all details are identical.
In the accompanying drawings, the same reference letters agree throughout.
Fig. 1. represents a front elevation of shutter,--A, the front plate ;-B, balance
weight on disc, C, the side of upper metal case,-D, the travelling disc, to
which is affixed the pin F, carrying the piston rod.-G, the pneumatic cylinder.―
E, the loose pawl,-P, the pneumatic tube.-J & K, diaphragmatic_slides,-all
within the dotted circle X is the sheath portion fitting into the slot of lens-tube.
Fig. 2. represents a back elevation of shutter.-H, the cover plate of upper
case enclosing the mechanism, I, the cover plate of sheath, enclosing the dia-
phragmatic slides.-E, pawl,-G nozzle of cylinder, all within the dotted
circle X, goes into the lens-tube and denominated the sheath.
Fig. 3. cover plates removed, showing details of mechanism with the slides at
full open C, the casing of upper portion,-L, the balance-rocker to which are
attached the two slides J & K.-N, the connecting rod, connecting the balance-
rocker to the rocking plate M,-R, the pin attached to the travelling disc D. and
passing through the curve slot of front plate A, and working the rocking
plate M, O & O', the guides to the slides.
Fig. 4. same as Fig. 3. but with the slides closed, and showing the position of
pin R in the slot.
Fig. 5. same detail as Fig. 3. but with a slight difference in form of rocking
plate M.
Fig. 6. front elevation of Fig. 5. showing, that by a slight alteration of position
of cylinder G, and the addition of trigger W, an elastic band Y, can be used as a
motive power.-D the same travelling disc as the others, only a larger boss, to
carry the elastic band; all other details are the same as Figs. 1 to 4.
Fig. 7. side elevation.-E, the pawl,-B, balance weight on travelling disc.-
F, pin connecting the piston rod to disc.-G, pneumatic cylinder.-T the sheath
portion in the lens-tube.-X the lens-tube shown in dotted lines.
Fig. 8. section of Fig. 7.-D travelling disc,-R, pin in disc passing through front
plate A. O. guide to slide-plates fixed to A.
Fig. 9. side elevation shows that by the addition of a short tube U, the shutter
is pushed onto the lens-tube X, and used in front, instead of in the slot, all other
details are identical.
Fig. 10. side elevation, shows that by the addition of two short pieces of
tube V & V', the shutter can be screwed into, or onto, portions of the lens-

page_text: mount X, X, and form one body, and used as a mid-lens shutter, all other details
are identical with Figs. 1 to 9.
Fig. 11. J & K, forms, and sections, of the diaphragmatic slide plates.
Fig. 12. an enlarged section of pneumatic cylinder G, and the partly spherical
formed piston Q.
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 form and manner of so constructing the combined upper and lower
portions of shutter which enables the sheath portion to pass into the slot of lens-
tube and contain the diaphragmatic slides to act as the exposing and closing of the
lens substantially as herein described; and illustrated in the accompanying
drawings.
2. The forms of all the members, or parts of mechanism, acting in the upper
case, and combined lower sheath, including the diaphragmatic slides and the manner
of actuating same from the outside portion of upper case, substantially as described,
and illustrated in accompanying drawings.
3. The form and use of the travelling disc, and the manner of actuating same
by the partly spherical form of the piston and connection with disc, and position
of pneumatic cylinder, enabling it to be so actuated; substantially as and for the
purpose herein described and illustrated.
4. The whole arrangement of the shutter the forms and uses of the different
members or working parts, substantially as and for the purposes herein described,
and illustrated, in the accompanying drawings.
Dated this 31st day of March 1892.
THOMAS FURNELL.