Improvements in Shutters for Photographic Cameras.
Year: 1891

page_text: Date of Application, 25th June, 1891
Complete Specification Left, 28th Aug., 1891-Accepted, 3rd Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
I, Jous KERSHAW of Spring Gardens, Buxton Derbyshire Photographer do
hereby declare the nature of this invention to be as follows:--
The improvements which are the subject of this invention relate to the means
employed for opening and closing the spring blind in the shutter of a photographic
camera, and the object of this invention is to construct a shutter that may be used
either as an instantaneous or a time shutter, without concussion or shocks, caused
by toothed wheels or like gearing where such are employed for the purpose of
opening or closing the spring blind.
In this invention for the purposes as herein above set forth, I construct a shutter
in which is a spring blind with an aperture therein for exposure of light to sensitive
plate, said blind being attached to liberating and receiving rollers contained in the
usual manner within the shutter.
At one side of the shutter and on one end of the liberating roller, I attach a
pulley. I connect to this pulley a cord, and at a prearranged part of said cord I
place a stop either by means of a knot formed in the cord or an attachment. To
the side of the shutter I connect a flat steel spring, said spring being caused to fit
against the face of aforesaid pulley, with a space under the pulley and between the
spring and side of shutter for a pneumatic bulb which is actuated through a tube
by means of a like bulb connected thereto and held by the operator. I place a stud
or stop on the face of aforesaid pulley, and a like stop on the inside of the flat steel
spring herein before described. I also attach a guide or guides in a suitable position
on the inside of spring and also to the shutter through which to pass the cord that
is attached to pulley on liberating roller.
In order to take a picture instantaneously by means of a shutter_constructed
according to this invention, 1 pass the blind from the receiving or tension roller on
to the liberating roller by means of aforesaid cord that is connected to and wound
on the pulley attached to end of liberating roller, by pulling said cord until it is
wound from the pulley when the stop or stud on face of pulley engages with the
stop or stud on inside of the flat steel spring herein before described, and prevents
the blind rewinding on to the tension or receiving roller.
When exposure is required, the operator presses by the hand the aforesaid
pneumatic bulb at the end of tube when the pneumatic bulb that is placed between
the side of shutter and the flat steel spring causes said spring to open outwards and
thereby release the liberating roller, by these means permitting the blind to be
rewound on tension roller, the aperture in blind having passed the aperture in
shutter in the interval.
"
When time exposure is required I turn a lever that is attached to shutter against
the guide through which the cord passes connected to inside of spring and the
same operation is performed as hercin last described, but the knot or attachment in
the cord is retained when passing between the aforesaid guide and lever, and
thus keeps the aperture in blind opposite the aperture in shutter until released by a
second pressure of the pneumatic bulb in the hand of the operator, when the shutter
is thereby closed.
In order to indicate the tension on the receiving or tension roller I form a worm
on the end of said roller. I attach to the side of shutter a worm wheel on which
figures are marked, the space between each figure corresponding to one turn of the
tension roller.
By these means the tension put on aforesaid roller is indicated by the figures

page_text: marked in the face of the worm wheel which is operated by the worm on end of
tension roller.
For the purpose of protecting the mechanism herein before described from injury,
hinge or otherwise attach a cover of sheet metal which may be thrown back for
inspection of mechanism or with apertures in said cover by which to obtain access
to any particular part.
Dated this 24th day of June 1891.
THOMAS PRESCOTT,
53, Arcade Chambers, St. Mary's Gate, Manchester,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Shutters for Photographic Cameras.
1, JOHN KERSHAW of Spring Gardens Buxton, in the County of Derbyshire
Photographer 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 improvements which are the subject of this invention relate to the means
employed for opening and closing the spring blind in the shutter of a photographic
camera, and the object of this invention is to construct a shutter that may be used
either as an instantaneous or a time shutter without concussion or shocks caused by
toothed wheels or like gearing where such are employed for the purpose of opening
or closing the spring blind.
I attain the object herein above set forth by mechanism illustrated in the
accompanying sheet of drawings, in which
Fig. 1. is a front view, and Fig. 2. a side view of a shutter for a photographic
camera, constructed according to my invention.
In these and other views shown on drawings to which I hereinafter refer, similar
letters refer to similar parts.
In this invention for the purposes as herein set forth, I construct a shutter b in
which is a spring blind e with an aperture therein for exposure of light to sensitive
plate, said blind being attached to liberating and receiving rollers e and f contained
in the usual manner within the shutter b.
At one side of the shutter and on one end of the liberating roller e I attach a
pulley connect to this pulley a cord h, and at a prearranged part of said
cord place a stop either by means of a knot formed in the cord, or an
attachment.
To the side of the shutter I connect a flat steel spring j said spring being caused
to fit against the face of aforesaid pulley g with a space under the pulley and
between the spring and side of shutter for a pneumatic bulb which is actuated
through a tube by means of a bulb 2 connected thereto and held by the operator.
1 place a stud or studs on the face of aforesaid pulley g and like studs or stops m
on the inside of the flat steel spring herein before described. I also attach a
guide in a suitable position on the inside of spring or to the shutter & through
which to pass the cord that is attached to pulley on liberating roller e.
In order to take a picture instantaneously by means of a shutter constructed
according to this invention, I pass the blind e from the receiving or tension roller
on to the liberating roller e by means of aforesaid cord that is connected to and
wound on the pulley 9 attached to end of liberating rollere by pulling said cord
until it is unwound from the pulley, when the stop or stud on face of pulley y
engages with the stop or stud m on inside of the flat steel spring herein before
described and prevents the blind rewinding on to the tension or receiving roller f
When exposure is required, the operator presses by the hand the aforesaid pneumatic
bulb at the end of the tube when the pneumatic bulb & that is placed between
the side of shutter b and the flat steel spring causes said spring to open outwards

page_text: as shown in Fig. 3. and thereby release the liberating roller e, by these means
permitting the blind c to be rewound on tension roller, the aperture in blind c
having passed the aperture in shutter in the interval.
R
When time exposure is required I turn a lever p that is attached to shutter b so
as to come against the guide as shown in Fig. 4. the cord 4 passing through the
guide a which is connected to the inside of spring j. When the operator presses
the pneumatic bulb & the liberating roller is released in the manner herein before
described, but the knot or attachment in the cord his retained when passing
between the aforesaid guide n and lever p as shown in Fig. 5. and thus keeps the
aperture in blind opposite the aperture in shutter until the liberating roller is again
released by a second pressure of the pneumatic bulb k² in the hand of the operator
and the shutter is thereby closed.
Fig. 6. represents a modification of the aforesaid lever and the guide n
both said lever and guide being formed of flat metal with a corresponding hole
in each.
When the spring is at rest these holes will come over each other, but when said
spring is pressed out taking the guiden with it, the hole in the lever P will be
partly covered by the guide n and made too small for the knot or stop in the
cord to pass through until released in the manner herein before described.
The lever p may occupy other positions on the side of the shutter than those
shown on drawings while acting in combination with the guide for the purpose of
checking the cord when time exposure is required.
In order to indicate the tension on the receiving or tension roller I form a
worm on the end of said roller. I attach to the side of shutter a wheel on
which figures are marked, the space between each figure corresponding to one turn
of the tension roller f. By these means the tension put on the aforesaid roller f
is indicated by the figures f³ marked on the face of the worm wheel which is
operated by the worm on end of tension roller f
For the purpose of protecting the mechanism herein before described, I hinge
or otherwise attach a covert of sheet metal which may be thrown back or taken
off for inspection of mechanism or with apertures in said cover by which to obtain
access to any particular part.
I desire that it should be understood I do not claim the use of a cord for operating
the spring blind in the shutter of a photographic camera but,
Having now particularly described and ascertained the nature of this my said
invention I declare that what I claim is
1st. In the shutter of a photographic camera for the purpose of obtaining
prolonged exposure the use of a cord in which a knot or stop at any prearranged
part of said cord and in combination therewith the lever p or other equivalent
attached to side of shutter and the guide, n attached to a spring, said spring being
arranged so as to control the liberating roller in the manner substantially as herein
before described.
2nd. In the shutter of a photographic camera the use of a worm wheel in
combination with a worm formed on the end of tension roller, said worm wheel
having mumerals marked thereon in order to indicate the tension placed on the
tension roller by the number of revolutions given to said roller in the manner
substantially as herein before described.
3rd. In the shutter of a photographic camera the combination and general
arrangement of parts as shown on the drawings for the purpose and in the manner
substantially as herein before described.
Dated this 27th day of August 1801
THOMAS PRESCOTT.
53, Arcade Chambers, St. Mary's Gate, Manchester,
Agent for Applicant.