An Improvement relating to Photographers' Roll-holders.
Year: 1892

page_text: Date of Application, 5th May, 1892
Complete Specification Left, 2nd Feb., 1893-Accepted, 22nd Apr.,
1893
PROVISIONAL SPECIFICATION.
An Improvement relating to Photographers' Roll-holders.
I, DAVID ROY, of 6 Holyrood Place, Plymouth, in the County of Devon,
Merchant, do hereby declare the nature of this invention to be as follows:-
This invention, which relates to photographers' roll-holders or slides, has for its
object to provide a check against more than one exposure of the same length of
film and consequent spoiling of pictures.
The invention consists in providing that the shutter, when replaced after
exposure of a length of film, is locked and is not free to be again withdrawn until
a fresh length of film has been unwound from the feed drum or roller.
Locking and unlocking are effected by means of a lever catch pivotted to the
body of the roll-holder. This lever catch, which is acted upon at its inner end by
a spring, is shaped at the opposite or outer end to form a wedge-shaped hook
which, when the shutter is locked, engages with a fixed stop provided on the
shutter. When a proper length of film has been unwound from the feed roller, an
arm attached to the winding indicator passes under a lug formed on the lever
aforesaid, and the latter is thereby raised, causing its catch end to become clear of
the stop on the shutter. The shutter is thus unlocked and made free to be
withdrawn.
In replacing the shutter, after exposure of the film the hooked end of the lever
is acted upon by a tongue pivotted to the shutter, and by this means the lever is
turned on its pivot to a sufficient degree to withdraw the arm aforesaid out of
engagement with the lug. The lever catch then falls and re-engages with the
fixed stop on the shutter. The latter is now locked and is not again free to be
withdrawn until a fresh length of film has been unwound from the feed roller.
ה'תנים
110M-1000
NICHOLAS WATTS,
Bristol Bank Buildings, Bristol, Chartered Patent Agent.
COMPLETE SPECIFICATION.
An Improvement relating to Photographers' Roll-holders.
I, DAVID ROY, of 6 Holyrood Place, Plymouth, in the County of Devons
Merchant, 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 :-
This invention, which relates to photographers' roll-bolders or slides, has for its
object to provide a check against more than one exposure of the same length of film
and consequent spoiling of pictures.
The invention consists in providing means whereby the shutter, when replaced
after exposure of a length of film, is locked and is not free to be again withdrawn
until a fresh length of film has been unwound from the feed drum or roller.
Locking and unlocking are effected by means of a lever catch pivotted to the
body of the roll-holder. This lever catch, which is acted upon at its inner end
by a spring, is shaped at the opposite or outer end to form a wedge-shaped hook
which, when the shutter is locked, engages with a fixed stop provided on the
shutter. When a proper length of film has been unwound from the feed roller, an
arm attached to the winding indicator cam passes under a lug formed on the lever
aforesaid, and the latter is thereby raised, causing its catch end to become clear of

page_text: the stop on the shutter. The shutter is thus unlocked and made free to be
withdrawn.
In replacing the shutter after exposure of the film, the nose of a tongue pivotted
to the shutter is pressed against the outer and inclined or curved end of the lever
which is thereby tilted upwards on its pivot to an extent which carries the lug
beyond the upper end of the arm aforesaid.
The lever catch then falls and re-engages with the fixed stop on the shutter.
The latter is now locked and is not again free to be withdrawn until a fresh length
of filin has been unwound from the feed roller.
In the accompanying sheet of illustrative drawings, Fig. 1 represents a side view
of a photographers roll-holder having applied thereto the catch in which this
invention consists. The shutter is shown closed but not locked. Fig. 2 is a view
as seen from the underside of the front of the shutter when closed and locked.
Pivotted at a to the body b of the roll-holder is a flat lever c which normally
lies in contact throughout with the body b. By the action of a spring d fixed at d'
and engaging at d with the lever c the latter is, in the absence of any counteracting
influence, tilted on its pivot a in such manner as, to maintain engagement between
its hooked forward end and a stop or tooth e rigidly fixed to the shutter f. Below
the stop or tooth e is a tongue g loosely pivotted at g' to the shutter f. The
tongue g is slotted at g² in order to receive the stop y³ and thus to control the limits
within which the tongue a is capable of swinging on its pivot g². Above the
winding indicator cam is a lug i provided on the lever c. This lug partially
overhangs the lever c. On the winding indicator cam h is an arm rigidly fixed
thereto and accordingly rotated therewith.
I
The upper face of the arm is above the level of the greater part of the lug i
on the lever c and the position of the arm h¹ on the indicator cam is so regulated
that at the close of winding off for exposure a proper length of film the upper end
of the arm passes below the top or roof of the lug which is turned up at one end to
permit the introduction of the arm which latter is bevelled at the introduced end
from the full height down to a knife edge for the same purpose.
The arm having thus been introduced into the lug i bears on the underside of
the overhanging part thereof and thus forces the hook of the lever c out of contact
with the side of the box (the said lever being able to spring to the necessary extent)
beyond the extremity of the stop or tooth e fixed as aforesaid to the shutter f which
is then free to be withdrawn. Withdrawal of the shutter f by the tab fl, or other-
wise, causes the loose tongue y to tilt on its pivot g', as seen at Fig. 3 and thus no
obstruction is thereby offered to withdrawal of the shutter.
After exposure of the film the shutter is replaced and on being pressed home the
front of the nose 9 of the tongue g is brought into contact with the outer and
inclined or curved face of the hook of the lever . The tongue g being prevented
by the stop g³ from swinging is thus made rigid, and the continued pressure of the
nose g against the hook causes the lever c to tilt upwards on its pivot a and thus to
carry the lug beyond the upper extremity of the arm on the indicator cam.
The lever e being thus released springs back to its normal position, that is to say,
flat throughout against the body of the roll-holder and in engagement with the
stop or tooth e fixed on the shutter. The latter cannot be again withdrawn until
a fresh and proper length of filin has been once more wound off.
Accordingly, two exposures on the same length of film cannot be made.
Having now particularly described and ascertained the nature of this invention,
and in what manner the same is to be performed, I would have it understood that
my invention is limited to the provision of a lock for the shutter of a roll-holder
and does not extend to the indicator cam per se but comprises the arm h¹ fixed
thereto and the conjoint action thereof, and I declare that what I claim is :-
1. In a photographers' roll-holder, the provision of a lock or catch whereby
the shutter when locked after exposure of a length of film cannot be withdrawn
until a fresh length of film is unwound from the feed drum or roller.

page_text: 2. A locking device for locking the shutters of photographers' roll-holders,
consisting of a hooked lever c pivotted to the body of the holder as at b and
carrying a lug i, a spring such as d acting on the said lever, a tooth or shoulder e
rigidly fixed to the shutter, a tongue or tappet g loosely pivotted to the shutter,
and an arm ' carried on the winding indicator cam; all constructed, arranged and
operating, substantially as hereinbefore described with reference to the accom-
panying sheet of drawings and for the purpose specified.
Dated this 25th day of January 1893.
NICHOLAS WATTS,
Chartered Patent Agent.