US1467812A - Fire-preventing device for motion-picture machines - Google Patents

Description

Sept. 11, 1923.

N. POWER FIRE PREVENTING DEVICE FOR MOTION PICTURE MACHINES Original Filed May 17, 1915 2'Sheots-Shoot 1 Witt om 3 mm wto'a faw m N. POWER FIRE PREVENTING DEVICE FOR MOTION PICTURE MACHINES Sept. 11, 1923.

Original Filed Hay 1'7, 1915 2 Sheets-Shoot Z Mew 5km wimme/a 1 My/f;

Patented Sept. 11, 1923.

UNITED, STATES PATENT OFFICE.

' NICHOLAS POWER, OF BROOKLYN, NEW YORK, ASSIGNOR T NICHOLAS POWER COM- PANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

FIRE-PREVENTING DEVICE FOR MOTION-FICTURE MACHINES.

Application filed May 17, 1913, Serial No. 768,210. Renewed December 17, 1919. Serial No. 345,583.

To all whom it may concern:

Be it known that I, NICHOLAS POWER, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and State of New York, have invented new and useful Improvements in Fire-Preventing Devices for Motion-Picture Machines, of which the following is a specification.

This invention relates to safety mechanisms for moving picture projecting machines and particularly to mechanisms for preventing the ignition of the film from the heat of the projecting are or lamp. In motion picture projecting machines as now generally constructed the essential elements comprise an electric are or other powerful and intense light with lenses for condensing the same on a picture and projecting the picture on the screen, a frame having an aplo erture correspl onding in size and shape to the individual; pictures on the strip, and a feed mechanism for intermittently feeding the successive pictures into registration with the aperture upon which the rays of light are condensed. The picture strips are composed of celluloid and are highly inflammable, so much so that-if the picture remains stationary in the path of the rays of light for an appreciable time it will be ignited by the intense heat of the light and perhaps cause a serious catastrophe, for even though the utmost care be employed in the matter of safeguards such as fire proof booths for the operators, the odor of the burnin film will often cause a panic in crowde theatres when the loss from the fire itself is most be later described. Flg. 6 1s a sectional View trivial.

To protect the film from the heat of the projecting lamp the projecting machines are 40 provided with screens which at all times cover the face of the film toward the light save the particular picture opposite the projection aperture, and when the machine is not in operation this portion of the. stri is covered by a door or fire shield w ich automatically closes the moment the rotation of the driving shaft ceases.

1t son'ietimes happens however that the v upper feed sprocket 5.

film will break below the projection aperture 5 leaving a portion of the film stationary in the projection aperture even though the rotation of the driving sprocket be continued, or it may happen that the film feeding devices slip or otherwise fail to feed the film so that it will remain stationary in line with the pro- ]B 0l31OI1 aperture long enough to become ignlted, and it is the object of my present inventlon to provide means operating automatically upon the breaking of the film or any failure of the feed mechanism to cut off the light from the projection aperture and thereby prevent the. film becoming ignited whether or not the driving shaft be continued in operation.

In theaccompanying drawings I have illustrated a preferred embodiment of my inventionwherein I accomplish the above mentioned results by means of a novel device op erating to close the automatic fire shield and also stop the feeding of the film from the magazine upon a departure of the film from its normal path of movement, such as would be caused by a breakage of the film or a portion of the feeding mechanism. It will of course be understood that other mechanisms than the one disclosed may be employed for the purpose, and also that other forms of safety devices may be operated in place of or in addition to the fire shield and that my invention is not therefore limited to the construction shown and described, but instead covers all such modifications thereof as fall within the scope of the appended claims.

In the accompanying drawings Figure I is a'side elevation partly in section of a portion of a moving picture machine equipped with my improved safety mechanisms;

Fig. 2 is a plan view of the mechanisms shown in Figure 1 and Figs. 3 to 5 are sect onal details which will of a modification.

Referring now to the drawings in which like parts are indicated by like characters throughout the several views, 1 indicates the frame of a projecting machine in which the film feeding mechanism is supported. Rotatably mounted in the frame 1 is a drivin shaft 2 which may be operated by a cranl; handle or power motor as desired. On top of the? frame 1 a bracket 3 is provided in whichis rotatably mounted a shaft 4 for the The sprocket 5 is continuously rotated as will be hereinafter described to feed the film 6 from an upper magazine not shown. From the sprocket 5 the film passes downward past the projection aperture 7 in the rear Wall of the frame ceivin v to the point of ignition.

1 into engagement with a sprocket 8'which is intermittently rotated from the main shaft 2 by suitable intermediate gearing.9 to successively feed the pictures on the strip into registration withthe aperture. The intermittent sprocket 8 remains stationary during the interval that the shutter of the machine is open while the picture is being projected, and then while the shutter is closed is given a partial rotation to feed the picture strip a sufficient distance to bring the next picture into registration with .the aperture. After leaving the intermittent sprocket 8 the film passes downward over a lower continuously operated sprocket 9 and thence into a remagazine where it is wound on a suitab e reel.

It will of course be understood that the interval that any one 'picture is stationary in the normal operation of the machine is not sufficient for the film to become heated Fer holding the film in engagement with the upper sprocket 5 I preferably provide an idler 10 movably mounted in any suitable manner to permit easy threading of the mahine. The idler l0 directs the film in an upward direction so that it turns and forms a loop as shown in full lines at 11 in Figure '3 before it reaches the guide-springs adjacent the projection aperture.- The machine is prefera 1y threaded up with a loop of about the s1'ze shown which will be maintained about the same size throughout the operation of the machine varying merely the amount fed at each single operation of the intermittent sprocket. The guide-springs 12 are mounted on the inner face of the rear door 13 of the machine which is closed against the film so that the springs hold the filmin proper alignment with the projection aperture. The door 13 is provided with apertures'15 of the same size and shape as the aperture 7, and covering the apertures 15 is a fire shield 16 which is hinged on a rod 17 extending across the rear face of the door above the aperture.

For operating the door 16 an arm 18 is attached to the rod 17 at one end which projects slightly beyond the side wall of the frame or head 1. When the door is closed the arm 18 extends rearwardly and upwardly from the rod as shown in full lines in Figure 1 and lies beneath a pin 19 in the side of .a link 20 which is pivotally mounted at its lower end to a lever 20 fulcrumed on a pin 20 in the side wall of the casing. The lever 20 is connected at its other end by a suitable pivot to the casing 21 of a centrifugal clutch 22 carried by a shaft 23 driven at high speed from the shaft 4 by means of a gear 30 and suitable connections. 'When' the machine is being operated with sufficient speed for the centrifugal clutch members to engage their casing 21, the lever 20 will turn on its pivot thereby depressing the pin 19 and the arm 18 and opening the fire shield. As the fire shield is'very easy to op-v well known form of moving picture machine,

the upper sprocket 5 being in such machine driven by a gear wheel fast on the shaft 4 and driven from a gear on the driving shaft 2. In the construction forming my present invention the gear wheel 25 for the upper sprocket is not fastened on the shaft 4 but is mounted for independent rotation and is provided on its inner face with a clutch member 26 adapted to be engaged by a similar clutch member 27 having a clutch face 28. Thehub of the clutch member 27 is elongated to form a sleeve 29 in which is formed a spiral slot. Mounted on the sleeve '29 between the clutch face 28 and a collar 28 is a ratchet .wheel 31. The hub of the ratchet is provided with a keyway 32 which overlies the spiral slot in the clutch member 27 and receives the end of apin 32 passing adjacent the ratchet,31 and pivotally mounted on this arm is a awl 33 for co-operation with the 'ratchet. t will be obvious that when the machine is in operation with the clutch members in engagement, the shaft 4: and the ratchet wheel 31 will be rotated with the clutch member 27 through the pin and slot connection, but if the pawl 33 be dropped into engagement with the ratchet the ratchet will be stopped but the clutch member 26 will continuein motion by reason of its engagement with the positively driven gear wheel 25, and the splral slot turning against the stationary pin 32 will move the clutch member 27 away from the gear 25 and thereby release the clutch and permit the upper sprocket to stop, while the rest of the mechanism may continuein motion.

Any suitable means may be provided to operate the pawl 33 upon the breakage of the film or other failure of the film feeding mechanism. In this application I have disclosed a novel and preferred mechanism for this purpose which mechanism, in addition to operating the pawl 33, also positively closes the fire shield 16 whenever the upper feed sprocket is unclutched as described. This mechanism comprises a chute or casing 35 enclosing the upper loop 11 of the film between the sprocket 5-and the guide roller 10. For convenience in threading the machine the chute is formed of two pieces 35 and 35*. The part 35* consists of a piece of sheet metal of angular cross section forming one side and one end of the chute rigidly supported immediately above the sprocket 5 by means of a bracket 36..

The part 35 is also composed of a piece of sheet metal of angular cross section and is rigidly attached to the upper edge of the door 13 so that when the door is closed it will lie adjacent the part 35v and form with it a rectangular casing completely enclosing the film. A cover 37 consisting of a comparatively heavy piece of metal is hinged along one edgeto the upper edge of the long side of the piece 35" and normally rests of its own weight on the upper edges of the chute35. At the end adjacent the ratchet wheel 31 the cover is provided with a rearwardly extendingarm 38 to which is 'pivotally connected a rod 39 whose lower end passes through an eye .40 formed on the pawl 33. Immediately beneath the eye 40 the rod 39 is provided with a collar 41 which when the cover 37 is closed and the arm 38 elevated will hold the pawl out of engagement with the ratchet but which when the cover is raised and the arm 38'depressed will allow the pawl to drop of its own weight into engagement with the ratchet.

The cover-"37 is provided at its opposite end with an arm 42 to which is connected a link 50 whose other end is pivotally connected to the horizontal arm of a bell crank 51 pivoted on the frame 1 above the end of the lever 20. The vertical arm of the bell crank lies behind the link 20 and is provided with a pin 52 rojecting through a slot in the link and ho ding the link in such position that when the fire shield 16 is in its open position, as shown by dotted lines in Figure 1, and the cover 37 is closed, the pin 19 will engage the arm 18 but if the cover be raised, as will be later described, the arm 51 will turnthe arm 20 to cause the pin 19 to release the arm 18 allowing the fire shield to close.

The operation of the mechanism will now be described. As explained above, the loop 11 in the normal operation of the machine is substantially constant in size as theintermittent sprocket draws the film out of the chute as rapidly as it is fed thereto by the continuous sprocket 5. If however for any reason the intermittent sprocket fails to feed the film, as for instance when the sprocket holes in the margin of the film are torn or mutilated, the film will be no longer drawn from the chute forthesprings 12 act as a brake on the film above the intermittent sprocket, thereby necessitating a positive engagement of the film to effect its" movement. The film will however continue to be fed into the chute for the sprocket 5" is rotated continuously and as it merely feeds the film from the upper reel, the resistance is so slight that a mere frictional engagement is sufiicient to effect the feeding of the film even though all the sprocket holes be entirel worn out. accumulation of the film in the chute causes the film to press up against the cover 37 lifting the same and thereby depressing the arms 38 and 42 allowing the pawl 33 to engage the ratchet wheel 31 and unclutch the sprocket 5 so that no more film will be fed from the reel, and also positivel closing the fire shield 16 thereby cutting o the rays of light from the projecting lamp before the film becomes heated to the point'of ignition. The closure of the fire shield also cuts off the picture from the screen and therefore notifies the operator who can immediately. stop the machine. and reset the machine for normal operation. As the ratchet is mounted between the clutch rim 28 and the collar 28 it will move longitudinally with the clutch member 27 and wheii the clutch is disengaged the pawlwill drop behind the ratchet and hold the clutch out of engagement.

It sometimes happens that a badly mutilated film will be fed past the sprocket 5 but a free'end of the film will be forced against the cover 37. In such cases there would. be a tendency for the end of the film to escape from the chute without raising the cover sufiiciently to operate the clutch or fire shield. To prevent this I form the cover with a curved lip which projects slightly within the chute as shown, and acts to-deflect the end of the film over against the rear wall of the chute where it will be stopped by the guide roller 10 and thereby form a loop in the film to raise the cover and operate the safety mechanism in the manner above described.

In Fig. 6 I have shown a slightly modified form of clutch mechanism for the upper sprocket. As here shown the shaft 4 has attached to one end a disk 60 having a clutch pin 61. Adjacent the disk 60 is the driving gear 62 loose on the shaft and having a pin 63 slidably mounted in a hole in the gear parallel to the shaft. The end of the pin is provided with a shoe rotatably engaging the pin' 61 when the operation of the lid 37 allows the pawl to drop. The pawl 33 of the modified form is of the same construction as the pawl 33 of the first described The a construction except that it is provided with a downwardly projecting pin to engage the cam faces of the clutch member instead of with the usual'point to lock with the ratchet teeth. The pawl 33 will be connected to the cover 37 of the film guide in the same manner as the pawl 33 of the first described construction.

The operation of this form of mechanism will be obvious from inspection; when the cover 37 is raised by the film the pin in the end of the pawl 33 will come into engagement with the inclined cam faces of the clutch member 64 so that the rotation-of the sprocket shaft will cause the clutch member to laterally shift, withdrawing the pin 63 from engagement with the pin 61. The shoulder at the end of the cam face as shown in dotted lines in Fig. 6 will engage the pin of the pawl 33 and thereby hold the clutch against further rotation, thus stopping the sprocket while permitting the free rotation of the driving gear 62. \Vhen the loop of film is reduced to normal proportions either by the continued operation of the machine in case the fault should be self-adjusting, or by the operator, the weight of the cap 37 will lift the pawl 33 out of engagement with the member 64 so that the spring will re-engage the clutch. and cause the sprocket to be again driven from the gear 62.

It will of course be understood that the fire shield operating device ma be used without the clutch actuating mec anism for the upper sprocket, but I prefer to use both devices for the reason that the film is fed quite rapidly and should the operators aton the screen he might operate the machine long enough after the fire shield had cut off the picture to feed a large quantity of the film out of the chute where it will be in danger of getting caught in the mechanism of the machine or otherwise damaged.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a motion picture machine the combination of a plurality of successive film feeding devices and means operated by an accumulation of film between said feed devices for stopping the first of said devices without stopping the succeeding devices.

2. In a motion picture projecting machine the combination of relative successive film feeding devices for feeding the film past the projection aperture, independent driving mechanism therefor, a shutter for screening said aperture from the light, connections between said shutter and said driving I mechanism for operating the shutterto uncover the aperture when the machine is operating, auxiliary means for closing said shutter, said means comprising a member positioned to be engaged by the film on a departure from its normal path of move ment, connections whereby movement of said member as effected by said film closes the screen, and means operated by said member for stopping the first of said film feeding devices without stopping the machine.

3. In a motion picture projecting machine,

the combination of a plurality of successive film feeding devices for feeding the film with a loop of slack between said devices, a guide for the loop of film for causing the enlargement of said loop to exert a thrust in a predetermined direction, means for controlling the operation of said feeding devices to prevent excessive enlargement of the loop without stopping the machine, a movable member positioned to be operated by the thrust of the film upon the enlargement of the loop, and motion transmitting connections betwee said member and an element of said means whereby movement of said member controls said means. 4. In a motion picture machine the combination of a plurality of successive film feeding devices, oa guide for causing the enlargement of a loop of film between said devices to'p'roject in a predetermined direction, means for rendering one of said feeding devices inoperative without stopping the ma chine, and means for operating said firstmentioned means comprising a member movably mounted in the path of enlargement of said loop and a member normally out of engagement with said loop and adapted to be actuated by the thrust of the film upon an enlargement of the loop, and motion transmitting connections between said member and said firs-t mentioned means.

5. In a motion picture machine having a source of light, the combination of a plurality of successive film feeding devices for feedin r the film across the path of light, a. guide for causing an enlargement of a loop of film between said devices to project in a predetermined direction a member normally! out of engagement with said loop and adapt ed to beactuated by the thrust of the film upon an enlargement of said loop and means operated by the movement of said member "for rendering the first of said feedin devices inoperative and for cutting o the light from the film without stopping the machine.

6. In a motion picture machine, the com bination with an intermittently and a. continuously rotated sprocket, a film! guide located between said sprockets and adapted to be moved'by an increase in the size of a loop in the film and means actuated by the movement of said guide for controlling the operation of said continuously rotating sprocket without otherwise afiecting the operation of the machines.

7. In a motion picture machine, the combination with '"intermittent and continuous sprockets of means interposed betweensaid Signed,at New York, in the county' of sprockets and controlled by an increase in New York and State of New York, this 14th the size of the loop formed in .the film beday of May, 1913.

tween said sprockets for controlling the -NICHOLAS POWER.

5 operation of said continuously rotatin Witnesses:

sprocket without aifecting the operation 0% A. J. LANG,

the other parts of the machine. J. S. STERRE'I'I.

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