US1230351A - Safety device for motion-picture machines. - Google Patents

Safety device for motion-picture machines. Download PDF

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US1230351A
US1230351A US12966616A US12966616A US1230351A US 1230351 A US1230351 A US 1230351A US 12966616 A US12966616 A US 12966616A US 12966616 A US12966616 A US 12966616A US 1230351 A US1230351 A US 1230351A
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film
circuit
plunger
contact
wire
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Harry E Watson
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FRANK B THOMPSON
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    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03BAPPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00Projectors or projection-type viewers; Accessories therefor
    • G03B21/14Details
    • G03B21/18Fire preventing or extinguishing

Definitions

  • HARRY E WATSON, OF RICHMOND, INDIANA, ASSIGNOR 0F ONE-HALF T0 FRANK B. THOMPSON, OF RICHMOND, INDIANA.
  • the object of my present invention is to provide an automatic cut-out or safety device for cinematographs or motion picture machines, which while being absolutely automatic in its operations, will be strong and durable in construction, simple in its arrangements, easily and quickly installed, inexpensive as to operation and maintenance, positive in action,
  • Figure 1 is a front elevation of my safety device
  • Fig. 2 is a rear elevation of the same
  • Fig. 3 is a vertical section of my safety device, as taken on the line 3-3 of Fig. 1.
  • Fig. 4 is a side elevation of the projecting machine for motion pictures
  • Fig. 5 is a side elevation of a portion of the lantern in which the light is produced for projecting the pictures carried by the film in the machine shown in Fig. 4.
  • Fig. 6 is a perspective view of the secondary contact.
  • Fig. 7 is a perspective view of the main contact.
  • Fig. 8 is a detail side elevation of the movable or contact-end of the main contact.
  • Fig. 9 is a diagrammatical plan view of the system of wiring the various partstogether.
  • Fig. 10 is a plan view of one of the sprocket rollers and a portion of a film which travels thereover.
  • Fig. 11 is a front elevation of the nozzle of the lantern and the shutter therefor, showing the latter in open position.
  • Fig. f is shown an ordinary projecting machine, in which letter A denotes the lens, B denotes the frame through which the light enters into the lens.
  • the light is projected from the lantern through the nozzle 0, which latter is in alinement with the'aperture in the frame B and with the lens A, the said parts being arranged in substantially the relations shown in Figs. 4; and 5.
  • Letter D denotes a shutter which is pivoted on'the front end of the nozzle C, and which is normally retained open or up, but
  • Letter F- denotes the film which passes over and is controlled by the two metal sprocket rollers G and H. .
  • the said rollers are geared to be revolved by a motor M, shown in Fig. 9, the same being connected to the opposite side of the machine from that shown in Fig. 1, therefore it does not appear in the drawings, but its means of connection to operate said rollers is common and is not related to this invention. From the above it will be seen that the film is to be carried vertically through the projected light whereby the pictures thereon will be projected through the lens in the usual manner.
  • the main contact arm 5 which carries a roller 6 which revolves on the central portion film F, or upon sprocket roller G when the film is not in position.
  • the arm 5 is insulated from the machine at its point of connection thereto.
  • the center arm 7 of the main contact whose outer end terminates in a cross-bar 8.
  • the rollers 9 and 10 mounted on the ends of said crossbar are the rollers 9 and 10 which are adapted to revolve on the edges of the film F and adjoining the sprockets of the sprocket roller Gr.
  • the inner, or upper, arm 11 of the main contact which also terminates in a cross bar 12 located at its free end, the cross bar 12 being located directly over but not in contact with the cross bar 8.
  • the adjusting screws 13 and 1 Threaded into the extremities of the cross bar 12 are the adjusting screws 13 and 1 1, whose points are adapted to approach near to the cross bar 8, and under certain condi tions to contact therewith.
  • numeral 17 denotes the base of my safety device. Secured on the back of said base is the transformer 18, which is for the purpose of reducing the voltage from the main line whereby it will be usable in the electro-magnet hereinafter referred to. Sccured in one end of the transformer 18 are the two wires R and S, and on the other end of the transformer are the two binding posts 21 and 22 to which are connected the respective wires 23 and 2%.
  • the elect-ro-magnet 25 which is carried by the bracket 26, which latter is secured to the base 17.
  • the wire 24 is connected to one pole of the magnet 25, and the wire a is connected to the other pole of the magnet 25, as indicated in Fig. 1.
  • the circuit breaker comprises an oblong flat plate 28, which is disposed vertically and it is secured flat on the face of the base 17. Located over and spaced outward from the plate 28 are the spaced apart guide-strips 29 and 30, the same being secured by a plurality of screws 31 and 32, respectively, which screws extend through the plate 28 and. into the base 17. Mounted to slide up and down in the channels between the strips 29? and the plate 28 is the plunger 33, which is in the nature of a Flat bar having on its lower end a tongue 34; which extends out between the strips 29 and 30 and at right angles to the plunger 33 with which it is integral. Near the center of the plunger 33 is an outwardly extending pin or pivot to which is connected the upwardly extending rod 36.
  • bracket 37 Secured to the base 17 below the center of the lower end of the plate 28 is the bracket 37, which forms a stop for the lower 9 end of the plunger to engage. To the outwardly extending portion of the bracket 37 is secured the lower end of the helical spring 38, the upper end of said spring being attached to the pivot or pin 35.
  • the clip 39 Located on the face of the guide 30, and near the center thereof, is the clip 39, and located directly to the right thereof and in horizontal alinement therewith is the clip 10, the latter clip being located on the block a1 which is carried by the base 17, in order to bring the clips 39 and 10 into horizontal alinement with each other.
  • the loops or channel portions of said clips 89 and 410 are also in horizontal alinement with the center of the magnet 25.
  • Mounted to slide hori zontally in the clips 39 and tO is the latchbar 4:2.
  • the left-hand end of the latch-bar is curved downward and to the left in order that the upper corner thereof may form a point to engage under the tongue 3 1, but at the same time permitting said tongue to slide upward past the bar 412 without engaging therewith.
  • the armature 13 Secured across the right-hand end of the bar -12 is the armature 13, which is located near the termini of the coils of the electromagnet 25.
  • a spring is attached to the center of the armature, with its other end secured to the center of the clip 39, whereby the armature is normally drawn away from the electro-magnet, and with the point of the bar 43 under and in engagement with the tongue 34 in order to support the plunger as in Fig. 1.
  • the small plate 45 Secured directly above the center of the plate 28, and spaced therefrom, is the small plate 45, and located thereon and with its lower portion extending out therefrom is the contact plate 46.
  • the plates 45 and 46 are secured together and to the base 17 by the screw 47
  • the space between the lower end of the contact 46 and the plate 45 is such as to receive the upper end of the plunger'33 therebetween.
  • the lower end of the cord E is attached to the upper end of the rod 36 whereby when the plunger 33 is upward to its limit, as in Fig. 1, the shutter D will be up, that is open or out of the path of the light from the nozzle C; but when the plunger has moved downward to its limit, as in Fig. 3, then said shutter will be closed, thereby shutting off the light from the nozzle C to the film.
  • Letter I denotes the source of electrical energy, from which extends the two main conductor wires J and K.
  • the wire J leads directly to one pole of the motor M, while the wire K extends to the screw 47, thereby connecting it with the contact 46.
  • the wire 0 is in fact a continuation of the main circuit to the motor. One end of the wire 0 is secured to the screw 32, while its other end is attached to the other pole of the motor M.
  • Letter P denotes the ground wire leading from the metal frame of the machine shown in Fig. 4 to the transformer 18, as shown in Fig. 9. Also the wire Q is grounded to the machine, the other end thereof being connected to the arm 7 The wire 24 is connected to one pole of the transformer 18, and its other end is connected to the electro-mag net 25.
  • Numeral 27 denotes a switch which is mounted on the base 17. Connecting one pole of the switch with the screw 32 is the wire T; and likewise connecting the other pole of the switch with the screw 47 is the wire U.
  • At least two forms of accidents are liable to occur to the film, either of which will make it desirable and in fact necessary to stop the machine with as little delay as pos sible: (a) The film may break or become completely separated at any point, or (b) one of the edges of the film may get out of mesh with the sprockets of one of the rollers H or G.
  • the said secondary circuit comprises the wire 24 leading from the magnet 25 to the transformer 18; the wire P from the transformer to the frame of the machine, and through the latter to one of the rollers 2 or 6, or through the wire Q, to the arm 7; then from the arm 1, or arm 11, through the wire 4, or wire 15, to the magnet 25.
  • the magnet would be magnetized, by reason of the current from the transformer 18 passing around the circuit as stated.
  • the trans former 18 is connected into the main circuit by means of the wires R and S forming a circuit thereinto, but operative only when the secondary circuit is established to draw therefrom.
  • the switch 27 is intended to permit the operator to break the main circuit and stop the motor at will, without the employment of the secondary circuit, or in case the magnet fails to operate.
  • the combination with a main power circuit, or a normally open secondary circuit connected to said main circuit means controlled by the film passing through the machine for closing said secondary circuit at different points in the travel of the film, said means comprising a plurality of metal film rollers grounded to the machine and forming one terminal of said secondary circuit, a plurality of movable contact members insulated from the .machine and forming the other terminal of said secondary circuit and normally held out of contact with said metal rollers by the film passing over the latter, and means for opening said main circuit upon the closing of said secondary circuit.
  • a mechanism of the nature set forth incorporated in the circuit extending from the source of power to the machine and comprising a magnet, a latch adapted to be operated by the mag not, a plunger held in the main electric circuit by said latch, a secondary circuit having contacts separated one from the other by said film and adapted to contact upon the breakage of the film to complete said secondary circuit to magnetize the magnet and thereby release the plunger in order to break the main circuit, and means connected to said plunger for automatically shutting off the light from said film simultaneously with the breaking of the main circuit, all substantially as shown and described.

Description

H. E. WATSON.
SAFETY DEVICE FOR MOTION PICTURE MACHINES.
APPLICATION FILED NOV. 6. 1916.
1,230,351 Patented June 19, 1917.
2 SHEETS-SHEET K.
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H. E. WATSON.
SAFETY DEVICE FOR monom PICTURE MACHINES.
APPLICATION FILED NOV. 6. l9l6. 1,230,35 1 Patented June 19, 1917.
2 SHEETS-SHEET 2.
m r-v2 W m 7 U/ m a JiEM/Qi'son! UNITED STATES PATENT OFFICE. I
HARRY E. WATSON, OF RICHMOND, INDIANA, ASSIGNOR 0F ONE-HALF T0 FRANK B. THOMPSON, OF RICHMOND, INDIANA.
SAFETY DEVICE FOR MOTION-PICTURE MACHINES.
Application filed November 6, 1916.
To all whom it may concern Be it known that I, HARRY E. WATSON, a citizen of the United States, residing in' the city of Richmond, in the county of Wayne and State of Indiana, have invented a new and useful Safety Device for Motion-Picture Machines, of which the following is a full, clear, and comprehensive specification and exposition, being such as will enable others familiar with the art to make and install the same with exactitude.
The object of my present invention, broadly speaking, is to provide an automatic cut-out or safety device for cinematographs or motion picture machines, which while being absolutely automatic in its operations, will be strong and durable in construction, simple in its arrangements, easily and quickly installed, inexpensive as to operation and maintenance, positive in action,
not liable to become inoperative, and which can be manufactured and sold at a comparatively low price.
It is well known by operators of cinematographs, or motion picture machines using transparent films, that the film on which the pictures are formed is highly inflammable or combustible and is liable at any time to be broken or to come apart or fail to properly mesh with the sprocket rollers over which it operates, and in such an event a part of the film becomes stationary directly aged, and in some instances it has caused the Specification of Letters Patent.
Patented June 19, 1917.
Serial No. 129,666,
tion, and that which is new will be corre lated in the appended claims.
The preferred means for carrying out my invention in a practical manner, and that which may be employed in actual practice, is shown in the accompanying two sheets of drawings, in whichFigure 1 is a front elevation of my safety device, and Fig. 2 is a rear elevation of the same. Fig. 3 is a vertical section of my safety device, as taken on the line 3-3 of Fig. 1. Fig. 4: is a side elevation of the projecting machine for motion pictures, and Fig. 5 is a side elevation of a portion of the lantern in which the light is produced for projecting the pictures carried by the film in the machine shown in Fig. 4. Fig. 6 is a perspective view of the secondary contact. Fig. 7 is a perspective view of the main contact. Fig. 8 is a detail side elevation of the movable or contact-end of the main contact. Fig. 9 is a diagrammatical plan view of the system of wiring the various partstogether.
Fig. 10 is a plan view of one of the sprocket rollers and a portion of a film which travels thereover. And Fig. 11 is a front elevation of the nozzle of the lantern and the shutter therefor, showing the latter in open position.
Similar indices denote like parts throughout the several views.
In order that the construction, the opera tion and the advantage of my invention may be better understood I will now describe the various features and the operations thereof as briefly and as comprehensively as I may.
In Fig. f is shown an ordinary projecting machine, in which letter A denotes the lens, B denotes the frame through which the light enters into the lens. The light is projected from the lantern through the nozzle 0, which latter is in alinement with the'aperture in the frame B and with the lens A, the said parts being arranged in substantially the relations shown in Figs. 4; and 5.
Letter D denotes a shutter which is pivoted on'the front end of the nozzle C, and which is normally retained open or up, but
it is adapted to close the front end of the nozzle when the cord E is pulled down a short distance.
Letter F- denotes the film which passes over and is controlled by the two metal sprocket rollers G and H. .The said rollers are geared to be revolved by a motor M, shown in Fig. 9, the same being connected to the opposite side of the machine from that shown in Fig. 1, therefore it does not appear in the drawings, but its means of connection to operate said rollers is common and is not related to this invention. From the above it will be seen that the film is to be carried vertically through the projected light whereby the pictures thereon will be projected through the lens in the usual manner.
All of said parts are of ordinary construction, and they are only referred to herein in order to make clear the application of my invention in connection with such machines.
Extending from the body of the machine shown in Fig. 4: is the secondary contact spring arm 1 whose free end carries the roller 2 which rolls in contact with the film F, or the sprocket roller H when the film is not in position. Connected to the arm 1, by the binding screw 3, is the wire 4., herein after referred to.
Likewise secured to the body of the ma chine shown in Fig. 4, is the main contact arm 5 which carries a roller 6 which revolves on the central portion film F, or upon sprocket roller G when the film is not in position. The arm 5 is insulated from the machine at its point of connection thereto. Corresponding with the arm 5, located thereover and parallel therewith, but insulated therefrom, is the center arm 7 of the main contact, whose outer end terminates in a cross-bar 8. Mounted on the ends of said crossbar are the rollers 9 and 10 which are adapted to revolve on the edges of the film F and adjoining the sprockets of the sprocket roller Gr. Also corresponding with the arms 5 and 7, and located over and parallel therewith, but insulated from the arm 7 and electrically connected at its base with the arm 5 of the main contact, is the inner, or upper, arm 11 of the main contact, which also terminates in a cross bar 12 located at its free end, the cross bar 12 being located directly over but not in contact with the cross bar 8.
Threaded into the extremities of the cross bar 12 are the adjusting screws 13 and 1 1, whose points are adapted to approach near to the cross bar 8, and under certain condi tions to contact therewith.
Extending from the arm 11 is the wire 15, the same being secured by the binding screw 16.
Referring now more particularly to Figs. 1, 2 and 3: numeral 17 denotes the base of my safety device. Secured on the back of said base is the transformer 18, which is for the purpose of reducing the voltage from the main line whereby it will be usable in the electro-magnet hereinafter referred to. Sccured in one end of the transformer 18 are the two wires R and S, and on the other end of the transformer are the two binding posts 21 and 22 to which are connected the respective wires 23 and 2%.
Located on the face side of the base 17 is the elect-ro-magnet 25, which is carried by the bracket 26, which latter is secured to the base 17. The wire 24: is connected to one pole of the magnet 25, and the wire a is connected to the other pole of the magnet 25, as indicated in Fig. 1.
The circuit breaker comprises an oblong flat plate 28, which is disposed vertically and it is secured flat on the face of the base 17. Located over and spaced outward from the plate 28 are the spaced apart guide-strips 29 and 30, the same being secured by a plurality of screws 31 and 32, respectively, which screws extend through the plate 28 and. into the base 17. Mounted to slide up and down in the channels between the strips 29? and the plate 28 is the plunger 33, which is in the nature of a Flat bar having on its lower end a tongue 34; which extends out between the strips 29 and 30 and at right angles to the plunger 33 with which it is integral. Near the center of the plunger 33 is an outwardly extending pin or pivot to which is connected the upwardly extending rod 36. Secured to the base 17 below the center of the lower end of the plate 28 is the bracket 37, which forms a stop for the lower 9 end of the plunger to engage. To the outwardly extending portion of the bracket 37 is secured the lower end of the helical spring 38, the upper end of said spring being attached to the pivot or pin 35.
Located on the face of the guide 30, and near the center thereof, is the clip 39, and located directly to the right thereof and in horizontal alinement therewith is the clip 10, the latter clip being located on the block a1 which is carried by the base 17, in order to bring the clips 39 and 10 into horizontal alinement with each other. The loops or channel portions of said clips 89 and 410 are also in horizontal alinement with the center of the magnet 25. Mounted to slide hori zontally in the clips 39 and tO is the latchbar 4:2. The left-hand end of the latch-bar is curved downward and to the left in order that the upper corner thereof may form a point to engage under the tongue 3 1, but at the same time permitting said tongue to slide upward past the bar 412 without engaging therewith.
Secured across the right-hand end of the bar -12 is the armature 13, which is located near the termini of the coils of the electromagnet 25. A spring is attached to the center of the armature, with its other end secured to the center of the clip 39, whereby the armature is normally drawn away from the electro-magnet, and with the point of the bar 43 under and in engagement with the tongue 34 in order to support the plunger as in Fig. 1.
Secured directly above the center of the plate 28, and spaced therefrom, is the small plate 45, and located thereon and with its lower portion extending out therefrom is the contact plate 46. The plates 45 and 46 are secured together and to the base 17 by the screw 47 The space between the lower end of the contact 46 and the plate 45 is such as to receive the upper end of the plunger'33 therebetween. The lower end of the cord E is attached to the upper end of the rod 36 whereby when the plunger 33 is upward to its limit, as in Fig. 1, the shutter D will be up, that is open or out of the path of the light from the nozzle C; but when the plunger has moved downward to its limit, as in Fig. 3, then said shutter will be closed, thereby shutting off the light from the nozzle C to the film.
Letter I denotes the source of electrical energy, from which extends the two main conductor wires J and K. The wire J leads directly to one pole of the motor M, while the wire K extends to the screw 47, thereby connecting it with the contact 46. The wire 0 is in fact a continuation of the main circuit to the motor. One end of the wire 0 is secured to the screw 32, while its other end is attached to the other pole of the motor M.
- lso leading from the source of power are the two wires L and N which form the circuit to the lantern for providing the light which is projected upon the film.
Letter P denotes the ground wire leading from the metal frame of the machine shown in Fig. 4 to the transformer 18, as shown in Fig. 9. Also the wire Q is grounded to the machine, the other end thereof being connected to the arm 7 The wire 24 is connected to one pole of the transformer 18, and its other end is connected to the electro-mag net 25.
Numeral 27 denotes a switch which is mounted on the base 17. Connecting one pole of the switch with the screw 32 is the wire T; and likewise connecting the other pole of the switch with the screw 47 is the wire U.
It will now be seen that if the motor M be operated that the film F will be carried over the rollers H and G, but to complete the circuit to the motor it is evident that the plunger 33 must be up, that is as it is in Fig. 1, in which case the current will pass through the wire K to the screw 45, then to the plate 45, then to the plunger 33, and
then through the guide'strip 30 to the screw 32, from which it will travel over the wire 0 to the motor. It is also evident that the point of the latch-bar 42 will hold the plunger up in contact position as long as the magnet 25 is not magnetized.
At least two forms of accidents are liable to occur to the film, either of which will make it desirable and in fact necessary to stop the machine with as little delay as pos sible: (a) The film may break or become completely separated at any point, or (b) one of the edges of the film may get out of mesh with the sprockets of one of the rollers H or G. In the first (a) it is evident that it would cause one of the contacts or rollers, 2 or 6, to engage the bare face of the roller H, or G, respectively; while in the latter, (6), it would cause one of the rollers 9 or 10 to be lifted, thereby raising the arm 7 until the cross-bar 8 contacted with the point of one of the screws 13 or 14, either of which would complete the secondary circuit, hereinafter followed out.
The said secondary circuit comprises the wire 24 leading from the magnet 25 to the transformer 18; the wire P from the transformer to the frame of the machine, and through the latter to one of the rollers 2 or 6, or through the wire Q, to the arm 7; then from the arm 1, or arm 11, through the wire 4, or wire 15, to the magnet 25. In this event the magnet would be magnetized, by reason of the current from the transformer 18 passing around the circuit as stated. The trans former 18 is connected into the main circuit by means of the wires R and S forming a circuit thereinto, but operative only when the secondary circuit is established to draw therefrom.
From the above it is manifest that if the rollers 2 or 6 are allowed to contact with the respective rollers H and G, or if the arm 7 be raised up slightly, then the secondary circuit will be established which will magnetize the magnet 25, thereby attracting the armature 43 which in turn will draw the latch-bar 42 from engagement with the tongue 34, and thereby permitting the plunger 33 to drop down, not only by gravity,
but by means of the spring 38, thereby breaking the main circuit at the point between the upper end of the plunger and the contact 46, as shown in Fig. 3. Therefore the power to the motor will be automatically cut off and the motor will stop, also at the same time the circuit to the transformer 18 will be broken, therefore the magnet 25 will be demagnetized and therefore the armature 43- will be released and will move back to set position drawn by the spring 44, thereby placing the catch again in operative position.
Now as the plunger 33 drops down it is evident that the cord E which is connected thereto will close the shutter D, thereby shutting off the intense light from the damaged stationary film.
Then as soon as the operator has repaired the film and placed it in operative position, as in Fig. 4, he has only to pull upward on the cord E to raise the plunger 33 until it is again engaged by the latch 42, thereby again establishing the main circuit to operate the motor as before, and also when the plunger 33 is moved upward to position it is evident that the shutter D will open to permit the light to again be projected upon the moving film.
The switch 27 is intended to permit the operator to break the main circuit and stop the motor at will, without the employment of the secondary circuit, or in case the magnet fails to operate.
I desire that it be understood that various changes may be made in the several details of construction and in the arrangement of the several parts without departing from the spirit of my invention and without sacrificing any of the advantages thereof.
Having now fully shown and described my invention, what 1 claim and desire to secure by Letters Patent of the United States, is-- 1. In an electrically operated motion picture machine, the comlnuation with a main power circuit of a circuit breaker normally closing said main circuit. a imrmally open secondary circuit connected with said circuit breaker and said main circuit, and automatic means for closing said secondary circuit whereby. to actuate said circuit breaker for the opening of said main circuit, said automatic means comprising a metal film roller forming one terminal of said secondary circuit, and a movable contact member forming the other terminal of said secondary circuit and normally held out of contact with said metal film roller by the film in its passage over the roller.
2. In an electrically operated motion picture machine, the combination with a main power circuit, or a normally open secondary circuit connected to said main circuit, means controlled by the film passing through the machine for closing said secondary circuit at different points in the travel of the film, said means comprising a plurality of metal film rollers grounded to the machine and forming one terminal of said secondary circuit, a plurality of movable contact members insulated from the .machine and forming the other terminal of said secondary circuit and normally held out of contact with said metal rollers by the film passing over the latter, and means for opening said main circuit upon the closing of said secondary circuit.
3. In combination with an electrically operated motion picture machine having a film operated thereby and means for projecting a light upon the film, a mechanism of the nature set forth incorporated in the electric circuit extending from the source of power to said machine and comprising an electro-magnct, a latch adapted 'to be operated by the magnet, a plunger held in the electric circuit by said latch, a secondary circuit for magnetizing the magnet, termi nal contacts for the secondary circuit lo rated at both sides of the light path of the machine, the same being in contact with the film and pressing the film against the metal rollers over which the film operates, and means whereby when the film is broken or damaged one of said terminals will contact with one of said metal rollers to complete the secondary circuit and energize the magnet thereby causing the latch to release the plunger and allowing the plunger to drop out of the main circuit and thereby cut oil the power which operates the machine, all substantially as shown and described.
i. In combination with an electrically operated motion picture machine having a film operated thereby and means for projecting a light upon the film, a mechanism of the nature set forth incorporated in the circuit extending from the source of power to the machine and comprising a magnet, a latch adapted to be operated by the mag not, a plunger held in the main electric circuit by said latch, a secondary circuit having contacts separated one from the other by said film and adapted to contact upon the breakage of the film to complete said secondary circuit to magnetize the magnet and thereby release the plunger in order to break the main circuit, and means connected to said plunger for automatically shutting off the light from said film simultaneously with the breaking of the main circuit, all substantially as shown and described.
In testimony whereof I have hereunto subscribed my name to this specification in the presence of two subscribing witnesses.
HARRY E. lVATSON.
Witnesses Rom. XV. RANDLE, R. E. RANDLE.
Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.
US12966616A 1916-11-06 1916-11-06 Safety device for motion-picture machines. Expired - Lifetime US1230351A (en)

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