Improvements in and relating to Stop-mechanism for Photographic Cameras, Projectors, and the like.
Year: 1899

page_text: Date of Application, 20th June, 1899-Accepted, 22nd July, 1899
COMPLETE SPECIFICATION.
Improvements in and relating to Stop-mechanism for Photographic
Cameras, Projectors, and the like.
We, WILLIAM STEVENS, of 419, Biddle Avenue, Wilkinsburg, Electrician, and
WINFIELD SCOTT BELL, of 433, Wood Street, Pittsburg, Merchant, both in
Pennsylvania, United States of America, 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 relates to an intermittent mechanical movement or 'ston-
mechanism, and as hereinshown as embodied in a camera or projector, in which
apparatus it is especially applicable for producing an intermittent feed of the
picture film, so that a prolonged stay or exposure of the picture and a quick
withdrawal of the same may be obtained, to thereby stop vibration on the screen
upon which the picture is projected, and which is painful to the eyes, and also
to avoid the rain effect now commonly produced on the said screens. This result
is obtained by a novel construction of feed movement for the picture film as will
be described.
Fig. 1 is a vertical section of one form of camera or projector embodying
this invention, the section being taken on the line 1-1, Fig. 2, looking toward
the right.
Fig. 2, a transverse section of the projector shown in Fig. 1 on the irregular
line 2-2,
Fig. 3, a detail of the feed movement to be referred to.
Fig. 4, a section on the line 4-4, Fig. 3 looking toward the left, showing
the parts in the position they occupy when the feed is about to take place.
Fig. 5, a view similar to Fig. 4, showing the parts in the position they
occupy during the progress of the feed.
Figs. 6 and 7, details to be referred to.
The movement which forms the essential feature of this invention, and which is
hereinshown as embodied in a camera or projector as the feed for the picture film,
comprises essentially two rotatable or movable members, which I prefer to
designate as the driving and driven members.
The driving member is preferably made as hereinshown, and consists of a
plate, ring or disc a provided with a central opening a¹, which fits over and
revolves upon a segmental journal, boss or projection a² having a re-entrant
portion 3, which imparts to the said journal approximately the form of a crescent
as shown in Figs. 4 and 5. The driven member consists of a substantially canoe-
shaped body or piece a, preferably of metal, and having its opposite faces 2, 3,
made in arcs of the same circle, namely, that of the circular opening a¹ in the
member a, the member as having its center within the opening a and adjacent
to the circumference of the circular opening a¹, and in order to permit the canoe-
shaped member a to turn on its center, the member a is provided with a recess
or opening as having one of its walls a made in the arc of a circle, which is
substantially the same as the circular sides 2, 3, of the driven member a for a
purpose as will be described.

page_text: The driven member a³ is provided with lugs or projecting arms a¹0 a13 extended
from its upper face substantially at right angles to the length of said members
and the said arms are adapted to be engaged by a pin, stud or projection a¹³ on
the driving member «, once for every revolution of said driving member.
The rotary movement of the driven member a is permitted by the opening a
in the driving member, which opening may and preferably will be of a width
equai to about one-ninth of the circumference of the circular opening a¹ in the
driving member, so that for eight-ninths of the circumference of said opening,
the driven member is locked against rotation. The driven member a is
turned one-half a revolution for each complete revolution of the driving member,
by the engagement of the pin or projection a³ with one of the arms a¹ a¹ and
by the end wall of the opening a
Referring to Fig. 4, the pin or projection a3 is shown as about to engage the
arm a of the driven member, the driving member a moving in the direction
indicated by the arrow 20.
As the driving member a is moved in the direction indicated by the arrow 20,
its pin or projection a engages the arm a¹0 and turns the member a about
its center and removes one circular side as 2 from engagement with the circum-
ferential wall of the circular opening a¹, bringing one pointed end of the
member a into the opening a8 as represented in Fig. 5, and at or about the time
the pin or projection a passes by or out of engagement with the arm a¹0, the
curved end wall of the opening 8, engages the opposite circular side 3 of
the driven member and continues the rotary movement of the driven member
until it has turned the latter one-half a revolution, at which time the circular
side 3 of the driven member is brought into engagement with the circumferential
wall of the opening and the driven member is thereby locked against rotary
movement, until the driving member has completed one revolution, and on the
second revolution of the driving member, the driven member is given another half
rotation by the pin at and wall a of the opening 8 engaging the other arm a¹ of
the driven member.
The mechanical movement hereindescribed is especially advantageous for use
with cameras or projectors as a feed movement for the film, and in Figs. 1 and 2,
I have shown the same adapted to a camera or projector consisting of a box or
casing, which contains two reels 13 mounted in suitable bearings in a frame-
work attached to a base 65, which latter supports uprights 66, 67, 68 (see Fig. 2).
The upright 6 suports in suitable bearings a rotary shaft 19 provided as shown
with a driving pulley 10 and with a disk 12 to which the driving member a
is suitably attached to revolve therewith about the segmental journal a secured
to or forming part of the upright 67. The upright forms a bearing for one
end of the shaft or pivot 4 for the driven member a, the other end of said shaft
being journaled in the upright 78. The shaft 4 has secured to it so as to form
practically a part thereof, a sleeve or hub 615 having at its opposite ends hubs or
projections 16, which form practically the teeth of a sprocket wheel, and which
are designed in practice to engage suitable holes or perforations at the opposite
sides of the picture film, not hereinshown, but which may be supposed to be
drawn off from the reel and wound upon the reel 2. The feed roll or
sprocket 15 has co-operating with it as hereinshown, suitable spring pressed
rolls 18, which hold the picture film in engagement with the feed roll.
The picture film is fed past an opening 20 in a lens box 21 containing suitable
lenses, 23, and is supported above the said lens box by a sprocket roll 2
with which co-operates spring actuated rolls 2. The sprocket roll 724 is rotated
in the same direction as the feed roll or sprocket by a gear 26 on the driving
shaft meshing with an intermediate pinion 627, which meshes with a gear 628 on
the shaft of the sprocket roll 24, the said gears being of the proper relative size
to regulate the speed of the sprocket roll 624 to the feed roll 615. The shaft
of the sprocket roll 24 is connected to the shaft 30 of the roll
wheels and a link chain
by sprocket

page_text: The picture film on its passage to the reel 2 may pass over a supporting
roller 0.
In practice the driving shaft 69 is designed to be revolved at a high rate of
speed, and consequently it will be seen, that the period of movement for the film,
which is preferably about one ninth the time it takes the shaft to make one
revolution, is substantially negligible, and, as a result, the pictures projected on
the screen are practically stationary, and the rain effect or vibration on the screen
is obviated, and the painful and injurious effect on the eyes of the spectator is
avoided, as the movement of the picture film across is imperceptible.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. A stop-mechanism, comprising a rotatable driving member having a circular
opening provided with a smooth circumferential wall, and a rotatable driven
member located within the said circular opening and having arc-shaped faces of
the same radius as the circular opening to engage said circumferential wall and
actuated by the driving member to make one-half a revolution while the driving
member is making a part of one revolution, and to remain locked for the
remaining portion of the revolution of the driving member, substantially as
described.
2. A stop-mechanism, comprising a rotatable driving member having a circular
opening to fit and turn upon a segmental journal or boss, and provided with an
opening as, and with a projection adjacent to the opening a³, and a rotatable
driven member consisting of a canoe-shaped body having circular sides 2, 3, of
substantially the same are as the circumferential wall of the circular opening
in the driving member, and provided with projecting arms which are engaged by
the projection on the driving member to turn the canoe-shaped body into the
opening, substantially as and for the purpose specified.
3. In a camera or projector, a main shaft, an intermittently locked feed-
mechanism for the picture-film operated by said main shaft and comprising a
rotatable driving member connected to the main shaft, a rotatable driven member
actuated by the driving member to make one-half a revolution while the driving
member is making a part of one revolution, and to remain locked for the
remaining portion of the revolution of the driving member, substantially as
described.
day of June 1899.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.