Year: 1897

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by
the decision of the Comptroller General of the 18th day of January 1898.
Date of Application, 6th Mar., 1897-Accepted, 10th Apr., 1897
I, SAMUEL SIDNEY BROMHEAD, of 97, Newgate Street, London, Patent Agent,
(a communication) 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:--
My invention relates to photographic cameras employed for taking a rapid
succession of views of objects in motion, from which the movements of said objects
may be reproduced to the eye, by means of a suitable apparatus.
Cameras heretofore devised for the taking of rapid successions of views or moving
objects have been defective in that they have been incapable of taking pictures as
large as is desirable, or of giving sufficiently long exposure to each picture to
enable photographs to be taken under ordinary conditions of illumination. In
these cameras, photographs are taken on a long, flexible, sensitive film, successive
portions of which are moved into the field of a lens and held stationary_while_a
shutter is opened to permit light passing through the lens to act upon the film. In
order that the ordinary movements of objects may be satisfactorily reproduced, it
is necessary that the series of views from which these movements are reproduced
shall have been taken at about the rate of 40 a second. While the shutter is open
and the light is acting upon the film the portion of the film exposed to the light
must be stationary, so that it is necessary to feed the film intermittently. If, in
order to produce the desired intermittent feeding of the film, the movement of the
entire film carrying and feeding mechanism be checked for each exposure, the
vibration set up in the camera by the sudden stoppage of the rapidly moving parts
of the mechanism prevents a distinct picture from being obtained, or makes it
necessary that the shutter shall be opened, each time, for so brief a time that
adequate exposure of the film is not obtained. If the spools from which the
unexposed film is unwound and upon which the exposed film is wound are permitted
to revolve continuously, while other mechanism which feeds and guides the film
across the field of the lens is caused to move intermittently, stopping each time
before the shutter is opened and commencing to move again after the shutter is
closed, although by this means the weight of the intermittently moving parts
is greatly reduced, it is still found that the sudden starting and stopping of these

page_text: parts of the mechanism causes troublesome vibrations which reduce greatly the time
during which the shutter may be open, and also that the intermittently moving film
feeding mechanism is incapable of moving with sufficient rapidity and of feeding
the film sufficiently rapidly to bring more than a very short length of fresh film.
into the field of the lens, without setting up excessive vibration.
These difficulties I have overcome in the camera herein described, by causing all
of the parts of the film-feeding mechanism to revolve continuously and uniformly,
a catch being used to hold the film stationary while the shutter is open, and the film
feeding rolls being permitted to slip over the film while the film is held by the
catch. This catch is extremely light and easily moved, and its operation causes no
vibration. All of the parts of the mechanism which carry or feed the film revolve
continuously and uniformly and therefore their operation causes no jar or vibration
of the camera.
The above constitutes a most important feature and advantage of my camera,
and is its most characteristic feature. Other advantages I will hereinafter
point out.
My invention consists in the novel means employed for intermittently feeding the
film across the field of the lens, in the novel means employed for rendering
the feeding of the film uniform, in the novel means employed for marking the film
to permit exact registry of prints made therefrom, in the novel means employed for.
reeling up the film after exposure and preventing the accumulation of unreeled film
in the camera, and in the novel combination, construction, and arrangement of the
parts of the apparatus.
The objects of my invention are, first, to provide a camera for taking a rapid
succession of views of moving objects, which shall be capable of taking larger
views, and of giving longer exposures, than the devices for similar purposes
heretofore used; second, to provide a film or strip feeding mechanism capable of
the intermittent feeding of longer lengths of film than has been practicable with
the film feeding mechanism heretofore used, and which shall be free from jar and
vibration in its operation; third, to provide a film or strip feeding mechanism which
shall not require previous perforation or other special preparation of the film, and
which shall not be liable to failure in operation owing to the slipping of the film;
fourth, to provide a film or strip feeding mechanism which shall not wear, tear or
otherwise injure the film; sixth, to provide means for marking the film at the time
and place of each exposure, to facilitate the bringing into registry of prints made
from the film, when the different views are to be mounted separately; seventh, to
provide means for reeling up the film which shall prevent accumulation of loose
film within the camera; and eighth, to make the camera simple in construction,
compact, portable and easy of operation.
These objects are attained in the camera herein described and illustrated in the
drawings which accompany and form a part of this application, in which the same
reference numerals indicate the same or corresponding parts and in which:-
:—
Fig. 1 is a side view of the camera, the side of the enclosing case having been
removed;
Fig. 2 is a plan view of the camera, the top of the enclosing case having been
removed; and
Fig. 3 is a front view of the camera, the front of the enclosing case having been
removed and a portion of the shutter disc having been broken away.
In the drawing, 1 is the enclosing case of the camera; 2 is the lens attached to
the front of the case 1; and 3 is a vertical frame plate, secured at the bottom
to the bottom of the case 1, which supports the film carrying and feeding
mechanism.
4 is the driving shaft of the camera. It is mounted in bearings in the case 1,
and one end projects outside of the case and carries a pulley 5, by which it may be
driven from a motor or other source of power.
6 is a spool carrying the strip of sensitive film upon which the photographs are
to be taken. It is mounted to revolve upon a spindle 7 projecting from the frame

page_text: plate 3, and a spool from which the film has been unwound may be removed and a
loaded spool placed on the spindle by removing the cotter pin 8. 9 is a spool upon
which the exposed film is wound. It is mounted upon a shaft 10, which is
revolvably mounted in a bearing within a boss 11 of the frame plate 3, and is driven
from the driving shaft 4 by bevel gears 12 and 13. The spool 9 and shaft 10 are
rotatably connected by a friction device hereinafter described.
14 is the main film feeding drum. It is secured to a shaft 15 having a bearing in
a boss 16 of the frame plate 3, and is driven from the shaft 4 by a worm wheel 17
and worm 18. Two small idler rollers, 19 and 20, are mounted upon spindles 21.
and 22, with their surfaces in contact with or in close proximity to the surface of
the drum 14. These rollers are loose upon their spindles, and are driven only by.
friction with the drum 14 or the film strip interposed between the rollers and the
drum. They serve to hold the film in contact with the surface of the drum. They
are preferably composed of, or have their surfaces covered with, some yielding and
elastic substance, so that possible injury to the film may be avoided.
23 is a plate secured to and projecting at right angles to the frame plate 3, and
located in the focal plane of the lens, which forms a support for the film during
exposure, and while the film is being punched as hereinafter described. 24 and 25
are auxiliary film feeding rolls, the function of which is to remove the exposed.
section of film and bring a fresh portion of the film into the field of the lens after.
each exposure. They are geared to revolve together at the same rate of speed, and
roller 24 is mounted upon a shaft 26, having its bearing in the frame plate 3,
and driven by bevel gears from the driving shaft 4. These rolls feed the film
forward intermittently, the film being held and prevented from feeding across the
plate 23, during about one half of the revolution of the shutter disc, by the catch
hereinafter mentioned, during which time the rolls slip idly over the film. Since
they act only intermittently, and must during the time of their action feed forward
as much film as has been fed forward by the drum 14 and roller 19 during a com-
plete revolution of the shutter disc, they are arranged to revolve at twice or more
than twice the peripheral speed of the disc 14.
27 is a flat spring, secured at one end to the frame plate 3, the other end being
arranged to press the film strip against the top of the backing plate 23. This
spring forms the catch by which the film is held stationary in the field of the lens
during exposure. Its free end is upturned, and is provided with a slot 28, in which
works a pin 29, secured to a revolvably mounted rock shaft 30, having its bearings
in the frame plate 3. The rock shaft projects through the frame plate, and upon
the rear side thereof carries an arm 31, which is directly over the shaft 4. Upon
the shaft 4 is an eccentric 32, and the eccentric strap 33 is connected to the arm 31
by an eccentric rod 34, having a hinged connection with the eccentric strap and a
universal joint connection with the arm 31. When the shaft 4 revolves the rock
shaft 30 is caused to vibrate. The amplitude of this vibration is sufficient to cause
the pin 29 to engage with the outer edge of the slot 28, each time, and lift the
spring 27 clear of the film and hold it so during the time the shutter of the camera
is closed.
35 is the shutter disc, by which the admission of light to the film is controlled.
It is a thin disc mounted upon and secured to the driving shaft 4, and situated just
in rear of the lens. A portion of its periphery is cut away, so as to leave the lens
uncovered during a portion of the revolution of the disc and thus to permit the
passage of light to the film. When the different views or prints made from the
negative strip produced by this camera are to be mounted separately, it is necessary
that some means shall be used for marking the position of each view on the strip
or film accurately, so that the views of the prints made from the strip may be
registered accurately when subsequently mounted separately. The marking of the
film for this purpose I effect by punching two holes in the film each time a new
length of film is fed forward. Upon the rock shaft 30, upon either side of the
pin 29, is mounted an arm 36, carrying a punch 37, which is arranged to punch a
hole through the film each time the shaft 30 vibrates. The plate 23 is perforated

page_text: to permit the punchings to escape. The holes thus punched are punched each time
at the instant when the exposure is made, and are always in precisely the same
position with respect to the center of the view. In printing from the negative
strip made in the camera after the pictures thereon have been developed, a sensi-
tized strip upon which the positives are to be printed is first run through the camera
or through a similar punching mechanism, so as to have the holes punched at the
same distance as are the holes in the negative strip. When the positive and negative
strips are placed in the printing frame for printing the registration holes are kept
in registry while printing is going on by means of dowels or other similar devices.
In preparing the camera for operation, a strip of film is first placed in position,
by opening the side of the case 1, which exposes to view the mechanism, placing a
spool of film on the spindle 7, and carrying the end of the film between the drum 14
and roller 19, over the plate 23 and under the catch 27, between the auxiliary feed
rolls 24 and 25, between the drum 14 and roller 20, and to the winding spool 9, to
which it is secured. The side of the case 1 is then closed, a loop being left between
rollers 24 and 25 and rollers 14 and 20, and the camera is in readiness for
operation.
In the drawings, the parts of the mechanism are shown in the position occupied
when the shutter is open and the exposure half completed. The spring or stop 27
is holding the film stationary against the top of the backing plate 23. The drum 14
is rotating in the direction of the arrow shown in Fig. 1, drawing film from the
spool which collects in a loop between the drum and the plate 23, since the film is
not being fed forward across the plate 23. A loop of exposed film which has
previously been formed, as will be seen hereafter, between the auxiliary feed rolls 24
and 25 and the drum 14, is being taken up through the feeding forward of the film
by the drum 14 and roller 20, and the film thus fed forward is wound upon the
rotating spool 9.
As the shaft 4 rotates, the edge of the shutter disc 35 cuts off light from the
lens. At the instant light is cut off the pin 29, moving upward, lifts the spring 27,
thus releasing the film. The auxiliary feed rolls 24 and 25 during the time that
the shutter is open simply slip over the film but are unable to feed it forward,
because it is held by the spring 27. But when this spring has released the film,
the rolls 24 and 25 instantly feed it forward. These rolls move at twice the
peripheral speed of the drum 14, as above stated. Therefore during the time the
light is cut off, they feed as much film across the plate 23 as has been fed into
the loop between the drum 14 and plate 23 during a complete revolution of the
shutter. The loop of film between the drum 14 and plate 23 is taken up, therefore,
during the time that the shutter is closed, the extra film in this loop corresponding
to the length of film required for a new exposure.
At the same time another and
corresponding loop is formed between the auxiliary feed rolls 24 and 25 and the
drum 14, since the film is fed forward much faster by the rolls 24 and 25 than it
is taken up by the drum 14 and roll 20.
Further rotation of the shaft 4 causes the shutter to open. Just before the
shutter opens the spring 27, which has been descending with the pin 29, touches
the film and holds it stationary against the plate 23. The auxiliary feed rolls,
being no longer able to move the film, slip over its surface. As soon as the shutter
opens, exposure begins and continues as long as the shutter is open, that is, during
about half the revolution of the shutter disc.
The rock shaft 30 still continues to move after the spring 27 has reached the
film on the plate 23, and by its further movement causes the punches 37 to punch
holes through the film as-above explained. These punches are withdrawn by the
backward movement of the rock shaft 30 before the pin 29 lifts the spring 27 and
releases the film.
It will be noted that all of the parts of the mechanism except the spring 27 and
the rock shaft 30 and parts connected therewith have a continuous, uniform, rotary
motion and therefore no jar or vibration results from their motion. The spring 27
and the rock shaft 30 and the parts connected therewith are so small and light,

page_text: have such small amplitudes of movement, and are so firmly supported that no jar
results from their movement.
The drum 14 and roller 19 are placed as close as possible to the plate 23, as are
the auxiliary feed rolls 24 and 25, so that the length of film set in motion by the
rolls 24 and 25 may be as small as possible. This done so that the film may,
start to feed across the plate 23 promptly, when released by the spring 27, and also
to avoid the danger of tearing of the film which results when a considerable length
of film is started into motion suddenly.
In practice, in order to avoid any danger of the gradual accumulation of film in
the loop between the drum 14 and the plate 23, due to possible slipping of the film
between the auxiliary feed rolls 24 and 25, I gear these rolls to revolve somewhat
faster than would be theoretically required, that is, in the machine shown in the
drawings, to revolve with somewhat more than twice the peripheral speed of the
drum 14, so that each time that the film is fed forward by the rolls 24 and 25
the loop between the plate 23 and the drum 14 is entirely taken up. In order to
provide for the gradual increase in diameter of the spool 9, upon which the exposed
film is wound, which tends to cause the spool to take up the film more and more
rapidly, the spool is not directly connected to its shaft 10, but is mounted loosely,
upon it, while the legs of a tripod shaped spring washer 38, itself so secured to the
shaft 10 as to be caused to revolve therewith, press against the spool 9 and cause
it is revolve by frictional contact. When the film between the spool 9 and the
drum 14 is tight, however, the spool will slip somewhat with respect to the shaft 10
and washer 38. All of the feeding rolls revolve continuously and uniformly and
therefore when the film is to be fed across the field of the lens it is never necessary
to overcome the inertia of any of the parts of the apparatus, only the inertia of a
very short section of the film requiring to be overcome. It is therefore possible
to feed a considerable length of film across the plate 23 in a brief time allotted for
that purpose. As shown in the drawings the shutter disc is arranged to admit light
during nearly one-half of its revolution. If desired the shutter may be arranged
to be open a much greater portion of the revolution than one-half, all that is
required being the cutting away of a greater portion of the periphery of the shutter,
a proportionate increase in the peripheral speed of the auxiliary feed rolls 24
and 25 with respect to the speed of the drum 14, and an adjustment of the amplitude
of movement and of position of the pin 29, so that the spring 27 may, be released
and lifted at the proper time. And because of the lightness of the parts and of the
fact that all of the parts which have directly to do with the feeding of the film move
continuously, as does the great body of the film, a much higher speed of the rolls 24
and 25 is well within the limits of the machine. In this manner the time allowed
for each exposure may be considerably increased.
It will be noted that the greater portion of the work of feeding the film, viz., the
drawing of the film from the roll 6, is done by the drum 14, and that the rolls 24
and 25 are required to feed only a very short and loosely. held length of film, so
that their hold on the film is very light and no injury results to the film because of
the slipping of these rolls upon it.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is;-
1. In a camera, a strip feeding mechanism, consisting of continuously moving
feeding devices acting upon the strip, and an intermittently operating catch
arranged to grasp the strip intermittently, thereby momentarily preventing the
feeding of the strip, substantially as described and shown in the accompanying
drawings.
2. In a camera, the combination, with a lens, and continuously moving film
feeding devices arranged to feed a strip of sensitive film across the field of the lens,
of an intermittently operating catch arranged to grasp the film intermittently,
thereby momentarily preventing the feeding of the film across the field of the lens,

page_text: a shutter arranged to cut off light from the film while the same is moving in the
field of the lens, and means for synchronously operating the shutter and catch,
substantially as described.