AN INSTANTANEOUS SHUTTER FOR USE IN OBTAINING PHOTOGRAPHIC PICTURES
Year: 1884

page_text: I, WILLIAM HEATH 24 George Street, Plymouth Optician and Mathematical
Instrument Maker do hereby declare the nature of my invention for AN
INSTANTANEOUS SHUTTER FOR USE IN OBTAINING PHOTOGRAPHIC PICTURES, to be
as follows:
By this invention the surface of a lens employed in obtaining photographic
pictures is exposed for unequal periods of time in its upper and lower portions,
thus admitting a larger quantity of light from the foreground than from the
distance proportionately. The plans for obtaining this result being shewn in
detail in the drawings and description which accompany this paper.
Fig 1. Shews the appearance of the front of the shutter when closed: it is a
wooden box of the size shewn, about 3/4" deep and is to be attached to the lens by
a sliding tube in the usual manner. The mill'd-bead by which the shutter is set is
also shewn.
Fig 2. Shews the means by which the movement is effected. The two sliding
plates being (as now shewn) coincident, allow the entire aperture of the lens to be
uncovered.
Fig: 3 Shews the form of the plates and of the apertures in the same, the
passage of which across each other in direct parallel movement permits of the
prolonged exposure of one portion of the lens in comparison with the other portion
of the same (which might be termed respectively the upper and the lower portions)
a result that is not attainable by plates with circular, square or rectangular
apertures, but which we do obtain by the triangular form here shewn, with or
without the point of the triangle cut off.
The sliding plates of the formn shewn in Figs: 2 and 3 are made to slide over
one another by means of a pin C attached to the upper plate, and travelling up
and down the slot in D, and a corresponding pin and slot for the movement of the
lower plate in the opposite direction.
E and F are bars connecting the arm D and the corresponding arm underneath
it with the spring box G and thus communicating the movement from the spring
in G at the same moment to the two shutter plates, but in opposite directions.
H is a brake for regulating speed.
I is a trigger for starting shutter.

page_text: WILLIAM HEATH 24 George Street Plymouth Optician, do hereby declare the
nature of my invention for A PHOTOGRAPHIC SHUTTER and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
For use in obtaining photographic pictures by means of which a longer exposure
of the foreground than of the distance is obtainable.
My method of doing this is exhibited in the diagrams which accompanied my
provisional specification, which I now refer to.
:
Fig. 1 Shews the appearance of the front of the Shutter when closed, being a
wooden box of the size shewn and about 3/4" deep it is to be attached to the lens
by a short sliding tube in the usual manner: the milld-head by which the shutter
is set, is also shewn.
Fig. 2. Shews the means by which the movement is effected: the two plates
being now coincident, allow the entire aperture of the lens to be uncovered.
Fig 3. Shews the form of the plates, the passage of which across each other
permits of a prolonged exposure of the upper portion of the lens, in comparison
with the other portion, a result that is not obtainable by circular square or other
form of aperture in plates, than the non-rectangular one, here shewn.
Fig. 2. Two metal (or other material) plates, of the form here shewn and made
to slide over one another by means of pin C attached to upper plate travelling
up & down the slot in D and a corresponding pin and slot for the movement of
the lower plate in the opposite direction.
E. and are bars connecting the arm D and the corresponding arm underneath
it, with the spring box G, and thus communicating the movement from the spring
in G, at the same moment and by the same movement.
H. is a brake for regulating speed.
I is a trigger for starting shutter.
Fig; 3. Shews the form & arrangement of the two parallel plates B B with an
aperture in each of the form of a triangle or portion of a triangle, the passage of
which across each other, produces an exposure for unequal periods of time of
different portions of the lens.
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 peculiar form of the shutter-plates the apertures in these being other
than circular or rectangular.
2. The application of the parallel motion to the shutter-plates.