US1880406A - Motion picture apparatus - Google Patents

Description

Oct. 4, 1932. F. L. BROWN 1,880,406

MOTION PICTURE APPARATUS Filed Nov. 28. 1928 INVENTOR firzzmwzzifivm BY Z2 ATTdRNEY Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE FREEMAN LEE BROWN, 01 WILMERDING, PENNSYLVANIA, ASSIGNOR T WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VAN IA MOTION PICTURE APPARATUS Application filed November 2a, 1928. Serial No. 322,368.

My invention relates to motion pictureapparatus, and it has particular relation to apparatus for the simultaneous reproduction of pictures and sounds from film-records thereof. Q

During the process of making a photographic sound-record on a light-sensitive film and during the process of reproducing the sound therefrom, it is necessary that the moving film shall be prevented from vibrating in the slightest degree. .It is also highly important that the film shall travel at an absolutely uniform speed past the point at which the record is made, or is reproduced, since even the most minor speedvariations cause unpleasant changes in the pitch of the reproduced sounds.

The two requirements, constant film speed and freedom from vibration, are diflicult to meet if the film is drawn through a film gate of the usual type by a constant-speed sprocket during the recording or reproducing processes, since the spring-pressed filmshoes exert a braking action on the film that causes a vibratory phenomenon, commonly known as chattering, very similar to that which occurs when a dampened finger is rubbed over a pane of glass.

It is, accordingly, an object of my invention to provide a film-gate particularly adapted to guide a film past the point at which sounds are to be photographically re corded thereon.

Another object of my apparatus is to provide a film-gate adapted for use in talkingmotion-picture apparatus.

Another object of my apparatus is to provide a film-gate wherein a film, during its passage therethrough, is prevented from transverse vibration and is not subjected to forces tending to cause longitudinal vibration.

Another object of my invention is to provide a film-gate wherein the film is forced to assume such a curvature that a. line of light falling upon it at the recording or reproducing point lies in an element of a cylinder, the axis of which is transverse to the motion of the film.

Another, and more specific, object of my provide an improved filmstructing a film-gate in the form of two-relatively movable curved plates, the curvature of the plates being such that the light from the recording or reproducing lamp impinges upon the film where its curvature is most pronounced. By reason of the greater rigidty given to the moving film through curving it at the recording and reproducing point, I am enabled to greatly reduce the spring tension with which the film-shoes are pressed agamst'it, thus lessening the tendency toward chattering of the film as it is drawn through the gate.

In addition, I have provided an improved film-shoe of a semi-floating type, which has suflicient resiliency to permit the passage thereunder ofa splice and, at the same time, exerts just the rightiamount of pressure upon the moving film.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims: The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment, when read in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a film-gate comprising a preferred embodiment of my invention, a film-guide-assembly being omitted therefrom for the sake of clarity.

Fig. 2 is a top view of the film-gate.

Fig. 3 is a perspective view of a film-shoe together with its accompanying tensionspring, and

Fig. 4 is a perspective view of the filmguide-assembly disassociated from the filmgate.

The apparatus illustrated in Figs. 1 and 2, constituting a preferred embodiment of my invention, comprises a front-gate-member 1 consisting of a front plate 2, having an aperture 3 therethrough, and a longitudinally curved front wear-plate 4. afiixed thereto by a plurality of screws 5.

The front wear-plate is provided with a plurality of longitudinally extending, oppositely disposed, raised tracks 6 and 7, on which tracks the edges of a film are adapted to ride in order that the central part of the film, including that portion of the emulsion thereon devoted to the pictures as well as the sound record, shall not come in contact with the plate.

The sound record, whether it is of the constant-density, variable-area type, or of the variable-density, constant-area type, is usually disposed longitudinally of the film, closely adjacent to the sprocket holes and, for that reason, the front wear-plate is provided with a light-opening 8 intermediate the tracks 6 and 7 and close to the'track 7. In order that the light-opening 8 shall be definitely located with respect to the aperture 3 in the frontplate 2, the wear-plate is provided with a plurality of dowel-pins 10 that extend through openings in the front-plate with minimum clearance.

It is highly important that the moving filir shall be prevented from side-slip during both the recording and reproducing processes and, to obviate the chances of slip, a plurality of edge-guiding discs 11 and 12, of the type shown in Fig. 4, are so mounted between pivots 13 and 14 carried by a plurality of upstanding ears 15 and 16 on the front plate that they make contact with the edges of the film in its passage through the gate.

The discs 11 and 12 are rotatably supported on a shaft 17, the disc 12, which is disposed adjacent to the edge of the wear-plate closest to the light-opening, being prevented from moving toward the pivot 14 by a collar 18 affixed to the said shaft. The discs are further provided with hub- portions 20 and 21 that extend toward, andmake contact with, each other intermediate of the discs, thus defining the minimum spacing therebetween. Inequalities in the width of a film are accommodated by permitting the disc 11 to move slightly axially of the shaft 17 against the pressure exerted by a small spring 22.

In order that a longitudinally-travelling film shall be prevented from movement axially of the openings through the front gatemember, means are provided for holding the edges of the film against the tracks 6 and 7 in its travel thereover. As shown in Figures 1 and 2, the holding means I prefer to employ comprises a plurality of frictionshoes of the type specifically illustrated in Fig. 3. Each friction-shoe comprises two U-shaped presser-feet 23, that are inter-connected through a fiat, resilient member 24 lying in a plane parallel to the plane defined by the wearing surfaces of the feet.

The friction-shoes are loosely mounted at the upper and lower ends, respectively, of a rear plate 25, the resilient members 24 of the shoes lying rearwardly of the plate and the presser-feet extending through openings in the plate toward the raised tracks 6 and 7.

In the drawing, I have shown the rear plate 25 as having a curvature similar to that of thefront wear-plate. Such curvature, however, is not necessary, it being sufficient that the friction shoes shall be so supported, in any convenient manner, that their wearing surfaces lie tangential to a curved surface parallel to the surface defined by the said tracks.

In order that the presser-feet shall be resiliently urged towards the tracks, a spring 26, having bent-down end portions 27, as shown in detail in Fig 3, is provided for each friction shoe. Each spring 26 is held firmly against the rear face of the rear plate 25 by a centrally disposed mounting screw 28, the upper one only of the said screws being visible in the drawing.

Each bent-down end portion of each of the springs 26 engages the inner surface of one of the presser feet constituting the friction shoe with which the spring is associated, the said presser-feet, accordingly, being individually and independently urged toward the film. By reason of the inter-connecting member 24, however, any movement of one of the presser feet is transmitted, in part, to its companion foot, thus permitting the friction shoe, as a Whole, to more easily override inequalities in the film caused by splices and the like.

The rear plate is affixed to a rear platecarrying member 30, the said plate and member being hereinafter designated the rear gate-member The rear plate-carrying memher, which has a large opening centrally thereof in alignment with an opening 31 extending through the rear plate, is provided with a plurality of diametrically disposed bosses 32. Each boss is provided with a passage-way through which extends a guide-pin 33 that projects laterally from a rear supporting-device 34, the bosses and the corresponding guide-pins constituting means whereby the rear gate-member may be slidably supported with respect to the front-gate member 1.

A pin 35, having a circular notch near the free end thereof, projects from the rear supporting device, and extends through an opening in the plate-carrying member 30 to cooperate with a gravity-actuated hasp 36. The pin and hasp constitute means by which the rear gate-member may be held in the open position, as illustrated in Fig. 1, against the pressure of a plurality of springs 37, each of which encircles one of the guide pins 33.

A finger piece 38 may be aflixed to the rear plate-carrying member 25 by a screw 40, as illustrated, for conveniently manipulating the gate, although this is not absolutely es sential.

- The rear supporting-device 34 should be rigidly connected to the front gate-member, it being preferable, for this purpose, to provide the said supporting device with a plurality of integral extensions 41 and 42 that are dove-tailed to the edge of the front-plate.

The rear-plate 25 should be provided with means for limiting the extent of its movement toward the front wear-plate 4, a plurality of small pins 43 projecting from the face of the rear-plate being satisfactory for this purpose. Only one of the pins is visible in Figure 1, the opposite pin being hidden behind the front-plate.

The rear supporting-device 34 is provided with a large central opening 44, in alignment with the openings through the front and rear gate-members, in which a photo-sensitive device may be disposed when my improved film-gate is utilized in a sound-reproducing machine. A cylindrical element 45 is preferably positioned in the opening 44 to shield the photo-sensitive device from light other than light falling thereon after having been modified by its passage through a sound-record.

I have not illustrated my improved filmgate as being afiixed to any particular part of a moving picture machine, a film-phonograph, or equivalent apparatus, inasmuch as the manner in which it is incorporated into such devices is immaterial.

From a careful consideration of the foregoing description, the operation of my improved film-gate should be substantially self evident to those skilled in the art. When it is desired to thread a film through the device, the finger piece 36 may be grasped to move the rear gate-member toward the rear supporting device. As the gate-member moves rearwardly, the pin 35 enters the opening in the gate-member provided therefor, and the pointed end thereof, engaging the hole in the gravity-latch 36, lifts the latterto such position that it is permitted to thereafter fall into the circular notch on the pin. To close the gate, it is only necessary to lift the end of the gravity-latch, permitting the edge of the opening therein to clear the notch in the pin, whereupon the springs 37 urge the rear gatemember forward until movement thereof is stopped by the limit-pins 43.

A film, in its travel over the front-plate is so curved that, at the location of the lightopening, a transverse element thereof is positioned in an imaginary cylindrical surface, the axis of which is parallel to the upper and lower edges of the said opening. The film therefore, cannot bend longitudinally, or wobble, immediately adjacent to the light opening, thus entirely eliminating one source of distortion that hitherto has been extremely troublesome.

Since the film, by reason of the curvature it is caused to assume in traveling through the gate, is largely prevented from bending longitudinally, and from wobbling, the resser-feet need only exert a very slight amount of pressure in order to hold the film between them and the tracks, and no pressure need be exerted on the film opposite to the light-opening. The reduction of pressure on the film substantially eliminates the chattering phenomenon hereinbefore referred to as a source of distortion, and is an important phase of my invention.

Although I have chosen a film-gate of a specific form for purposes of illustration, my invention is not to be limited thereto, but it is to be restricted solely by the limitations imposed thereon by the prior art and by the spirit of the appended claims.

I claim as my invention.

1. In apparatus for use in connection with a photographic film, a front gate-member having a face provided with tracks at the opposite sides thereof adapted to support a film, the central portions of said tracks having the surfaces of congruent sections of a cylinder and the end portions of said tracks having the surfaces of planes tangent to the sections of the cylinders at their extremities and coextensive with them, and means for resiliently urging a film against said tracks, said means coacting with said film along said end portions.

2. In apparatus for use in connection with a photographic film, a front gate-member having a face, the central portion of which has the surface of a cylinder and the end portions of which have the surfaces of planes tangent to and coextensive with said cylindrical surface at its extremities, a rear gatemember having a plurality of shoes to engage said front gate member on said end portions, and means for resiliently urging said rear gate-member toward said front gate-member.

3. In film-handling apparatus, an aperture-plate, a shoe-carrying plate, means for slidably supporting said shoe-carrying-plate, spring means for urging said shoe-carryingplate toward said aperture-plate, means for guiding said shoe-carrying-plate in its motion relative to said aperture-plate, means for limiting the distance between said shoe-carrying-plate and said aperture-plate to a predetermined value, means for locking said shoecarrying-plate in a position away from said aperture-plate, means for laterally guiding the film in its passage over said apertureplate, and means for resiliently clamping said film against said aperture-plate.

In testimony whereof, I have hereunto subscribed my name this 23rd day of November,

FREEMAN LEE BROWN.

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