US2099376A - Motion picture and sound reproducing machine - Google Patents

Description

Nov. 16, 1937. A. SHAPIRO MOTION PICTURE AND SOUND REPRODUCING MACHINE Filed June 26, 1936 2 Sheets-Sheet l NOV. 16, 1937. SHAPIRO 2,099,376

MOTION PICTURE AND SOUND REPRODUCING MACHINE Filed June 26, 1936 2 Sheets-Sheet 2 5 I Q 6/ 67 f, g Z a 4/ I Patented Nov. 16, 1937 UNITED STATES PATENT OFFICE MOTION PICTURE AND SOUND REPRODUC- ING MACHINE corporation of Illinois Application June 26, 1936, Serial No. 87,438

6 Claims.

This invention relates to motion picture machines which are equipped with means for producing sound through the well known media of a sound track on the film and an exciter lamp projecting a beam of light through the sound track onto a photo-electric cell, exciting minute currents in the latter which, through a loud speaker, are translated into vocal and instrumental sounds.

One object of the present invention is to pro- 16 vide an improved, compact, and highly efiicient sound reproducing mechanism of that type wherein the film having a sound track thereon travels over and rotates a drum, within which drum is a photo-electric cell and a stationary tube encircling the cell and formed with a narrow slot, and an exciter lamp is so mounted as to pro- J'ect a straight light beam across the sound track and through the slot onto the cell.

A quite common fault heretofore. existing in the 2 performance of the sound reproducing mechanism of motion picture projectors lies in a more or less tremulous or undulating sound elfect that is due to minute vibrations or fluctuations of the film as it passes across the light beam projected through the sound track onto the photo-electric cell. I have found that the sound reproduction may be greatly improved by imposing on the film as it travels through the sound reproducing mechanism a light uniform tension which aids in eliminating such vibrations; and a further feature of the present invention resides in an improved means for thus tensioning the film as it travels across the sound reproducing mechanism.

Still other and more specific objects of the invention will be apparent to persons skilled in the art the same becomes better understood by reference to the following detailed description, taken in connection with the accompanying drawings in which I have illustrated a preferred embodiment of the improved features of the invention, and wherein:-

Fig. l is a fragmentary side elevation, partly in vertical section, of those parts of a motion picture projector to which the present invention relates.

Fig. 2 is an opposite side elevation of the lower portion of Fig. 1.

Fig. 3 is a vertical section through the sound reproducing mechanism, taken on the line 3-3 Fig. 4 is an axial section through the film tensioning mechanism, as seen on line 4-4 of Fig. 1. Fig. 5 is a perspective detail of the main supporting casting that carries the sound reproducing el ments and adjunctive devices, and the arm of the take-up reel when the machine is used with a sound film.

Since this invention relates particularly to the sound mechanism, the accompanying drawings show only as much of the entire projector as will be of assistance in apprehending the invention.

In the construction illustrated, the casing of the machine, which is only partly shown, includes a lamp compartment I0 having a front wall II provided with a central aperture I2 and a for- 10 wardly extending gear box I3 in which is mounted a train of gears for driving the film sprockets I4 and I5 from a motor, partially indicated at IE.

IT designates the usual adjustable lens mounting, between the inner end of which and the wall I I is 15 formed the film guideway I8. A bracket arm I9 mounted on the top of the gear box I3 carries the delivery reel (not shown), and below the aperture I2 is mounted the usual feeding claw (not shown) for effecting the rapid step-by-step movement of the film 2 I.

The structure above outlined is substantially identical with that disclosed in patents to Sapier No. 1,780,945, November 11, 1930 and No. 1,816,234, July 28, 1931.

Coming now to a description of my present improvement in and relating to the sound mechanism, this mechanism is designed to cooperate. with a film such as 2I that is equipped with the usual marginal holes 22 for engagement with the teeth of the sprockets I4 and I5 and, just inside one line of holes, with a sound track photographed thereon at the location indicated by 23 in Figs. 3 and 4. On the under side of the gear box I3 is an integral depending bracket 24 to which is secured by a screw 25 a lateral boss 26 on the upper end of a main mounting plate 21 preferably consisting of a casting having a lateral flange 28 strongly secured by screws 29 to the face of a boss 3| on the frame of the motor I6. On the opposite edge of the plate 21 from the flange 28 is an integral bracket 32 to which is pivoted at 33 an arm 34 that carries the film take-up reel (not shown). As shown in Fig. 1, an inwardly projecting portion 35 of the arm is formed with a pair of holes 36 that cooperate with a spring pressed detent pin 31 mounted in a lateral boss 38 on bracket 32 to support the arm 34 in either of two positions.

On one side of the plate 21 are vertically spaced hollow bosses 39 and M (Fig. 3). In boss 39 is mounted an insulating sleeve 42, within which in turn is mounted a brass tube 43 that forms a. housing and support for a horizontally disposed photo-electric cell 44. One end of the housing 43 may be closed by a cap plug lli. Attached to the other side of the supporting plate Zl is a bracket plate 49, on which is an integral hollow boss ll containing spaced ball bearings 48 for a shaft 49. On the inner end of shaft 99 is a hollow drum 5!! that encircles, without contact, the inner end portion of the cell housing 93 and cell l i. Keyed on the opposite end of the shaft 49 is a fly wheel 52. 53 is formed the usual narrow slot or slit 53 (Fig. 3) through which the light beam from the exciter lamp is projected onto the photo-electric cell All.

In a bracket 54 on the opposite side of the plate 21 from the bosses 39 and M is mounted the usual lens holder and lenses designated as an entirety by 55; and vertically beneath the lower end of the lens holder is the filament 59 of the exciter lamp, the bulb of the latter appearing at 51, and the neck 58 of the lamp having soldered thereon a radial flange 59. A fiber washer 6i loosely encircles the neck 58 and is formed with peripheral notches occupied by rubber washers 62 that, in turn, are attached to the outer face of the boss M by screws 63. The flange 59 carrying the lamp is removably secured to the washer 95 by three spaced pins 9d formed on one end with knobs 65 that are engaged with bayonet slots 66 (Fig. l) in the flange 59. The pins 64 extend through holes in the washer 6i and also through holes in a flange Bl on the inner end of a lamp socket B8 in rear of and partly surrounding the lamp neck 58, and between the washer iii and flange til are thrust springs 99 encircling the pins (it, and holding the lamp flange 59 securely against the supporting washer 6 l, and the center terminal of the lamp in contact with one of the wire terminals. Surrounding the socket 68and secured by the screws 69 is a flanged housing ll through which the leads to the lamp extend.

The lens 55 and lamp 5'! are preferably protected by a cover plate i2 that may be attached to the plate 21 as by screws 19.

The path of travel of the film below the vertical film guideway and through the sound reproducing mechanism is shown and indicated by arrows in Fig. 1. The drum M is driven by the film, and, to insure a continuous and uniform drive it is necessary that the film be under sufficient tension to maintain the rotation of the fly wheel 52, and also to prevent vibration of the film at and adjacent to the point where it crosses the light beam that energizes the photo-electric cell, since any such vibration deleteriously affects the quality of the sound. I have accordingly designed a film tensioning device located in advance of the sound reproducer, and consisting of a pair of friction rolls between which the film passes, at least one of the rolls being associated with means for imposing a light drag on its rotation.

Describing this film tensioning device, the location of which is shown in Figs. 1 and 2 and the structural details of which are shown in Fig. 4, in an ear M on the upper end of the mounting plate 27 is secured a stud E5 on which is journaled a brass roll it. The end portions of this roll are annularly countersunk as shown at H to avoid contact with the edge portions of the film. On'the stud 15 are friction washers l8 and 19 bearing against the ends of the roll 19, and in one end of the stud i5 is a screw 8! the head of which bears on the washer l8 and confines the roller on the stud. In one side of the ear M In the cell housing is a recess 82 to house a light thrust spring 83 that creates friction between the washer l8 and the head of the screw Bl, thus creating a light drag on the rotary movement of the roll. On one side of the mounting plate 2'! is pivoted by a screw 85 the lower end of an arm 89. In the free upper end of arm 89 are a pair of holes 8? (Fig. 2) in either of which is secured a stud 88 on which is journaled a cooperating roll designated as an entirety by 99 in Figs. 1 and 2. The specific structure of roll 89 is shown in Fig. 4, wherein it will be seen that the roll comprises a tubular body 9!, ends or heads 92, and an annulus 93 of felt or like soft material between the heads 92. The inner portions of the heads 92 are reduced in diameter sufliciently to avoid contact with the edge portions of the film, while the felt sleeve 93 is of sufiicient diameter to bear on the front or picture side of the fihn without marring the latter. In the outer end of stud 88 is a knurled thumb screw 94 that confines the roll on its bearing stud between a pair of washers 95. The central portions of both studs are slightly reduced, as shown, to receive oil. A spring 96 urges the arm 85 and its roll 89 toward the cooperating roll 19.

From the friction rolls above described the film travels over a stationary guide shoe 91 mounted on the supporting plate 21, thence around the lower half of the rotary drum 5!, thence over a second stationary guide shoe 98 mounted on the plate 21, and thence over the film feed sprocket l5. As the film leaves the sprocket IE it is lifted to carry the same out of engagement with the sprocket teeth by means of a guide shoe 99 underlying the film and having a hump lilll extending beyond the path of the sprocket teeth onto which the film rides, thus lifting the film clear of the teeth before the latter withdraw from the holes in the film.

The purpose of these shoes 9?, 98, and 99 is to prevent vibration of the film as it travels to, through and beyond the sound reproducing mechanism, since, as hereinabove stated, even the slightest vibration of the film as the beam of light travels across the same, impairs the quality of the sound, creating an undulating sound eifect. These film guides, however, constitute no part of my present invention, but form the principal subject matter of a copending application of Allen Shoup, Serial No. 87,437, filed June 26, 1936.

Pivoted on a stud 25! mounted in an ear I92 on an edge of the plate 2'! is an arm 0133, On the free end of which is journaled a pulley Hi9 which maintains the portion of the film 2i between the feed sprocket i5 and the take-up reel under a light tension, the arm m3 being urged downwardly by a spring M35. The purpose of this pulley is to prevent sudden jerks on the film due to the action of the take-up reel. If a big jerk occurs, as when starting the reel, the spring allows the pulley to rise and thus prevents excessive strain on the film such as might break the latter. This feature, however, is not claimed herein, since it forms in part the subject matter of the copending application of Allen Shoup, above identified.

The herein described construction of the sound mechanism readily enables the machine to be converted into a silent machine-that is, a picture projector using a film having no sound record, by simply withdrawing the screws 25 and 29, and removing the plate 2'! and the parts carried thereby, and detaching the take-up reel bracket arm 39 from the bracket 32 and mounting it on the gear box bracket 24.

Although but one specific embodiment of this invention has been herein shown and described, it will be understood that specific changes in the structural details and arrangements of the device may be resorted to within the scope of the inven tion as defined in the following claims.

I claim:

1. In a sound mechanism for use with moving picture films having a sound track, the combination of a mounting plate formed with a transverse opening, an insulating sleeve mounted in said opening, a tube mounted in said sleeve having a portion thereof projecting beyond one end of said sleeve and formed with a narrow slot, a photoelectric cell housed in and supported by said tube, a portion of said cell lying opposite said slot, a hollow rotatable drum formed with an open end encircling with slight clearance only the projecting portion of said tube beyond said slot, said film passing over and driving said drum, and an exciter lamp and lens mounted on said mounting plate laterally opposite said tube in a position to project a straight light beam directly across the sound track on the film through said slot and onto said cell.

2. In a sound mechanism for use with moving picture films having a sound track, the combination of a mounting plate formed with a transverse opening and a. hollow integral boss registering with said opening, an insulating sleeve mounted in said boss and extending through said opening, a tube mounted in said sleeve having a portion thereof projecting beyond one end of said sleeve and formed with a narrow slot, a photo-electric cell housed in and supported by said tube, an end portion of said cell lying opposite said slot, a hollow rotatable drum formed with an open end encircling with slight clearance only the projecting portion of said tube beyond said slot, said film passing over and driving said drum with the sound track thereof overhanging said slot, a cap closing the open end of the projecting portion of said tube, and an exciter lamp and lens rigidly mounted on said mounting plate laterally opposite said tube in a position to project a straight light beam directly across the sound track on the film through said slot and onto said cell.

3. In a sound mechanism for use with moving picture films having a sound track, the combination of a mounting plate formed with a transverse opening and a hollow integral boss on one side thereof registering with said opening, an insulating sleeve mounted in said boss and extending through said opening beyond the opposite side of said mounting plate, a tube mounted in said sleeve having a portion thereof projecting beyond one end of said sleeve and formed with a narrow slot, 3, photo-electric cell housed in and supported by said tube, an end portion of said cell lying opposite said slot, a hollow drum formed with an open end encircling with slight clearance only the projecting portion of said tube beyond said slot, said film passing over and driving said drum with the sound track thereof overhanging said slot, a cap closing the open end of the projecting portion of said tube, a bracket mounted on the side of said mounting plate opposite said hollow boss, anti-friction bearings mounted in said bracket, a shaft on said hollow drum journaled in said bearings, a fly wheel mounted on a projecting portion of said shaft beyond said bearings, and an exciter lamp and lens rigidly mounted on said mounting plate laterally opposite said tube in a position to project a strai ht light beam directacross the sound track on the film through said slot and onto said cell.

i. In a machine of the class described, the combination with a film having a sound track thereon, and sound reproducing means through which said film travels, of means for tensioning said film in advance of said sound reproducing means, comprising a pair of rolls between which the film passes, one of said rolls having a soft periphery for contact with the face of the film, means for imposing a drag on the rotation of one of said rolls, and means for lightly compressing said rolls onto the film.

5. In a machine of the class described, the combination with a film having a sound track thereon, sound reproducing means through which said film travels, of means for tensioning said film advance of said sound reproducing means, comprising a pair of rolls between which the film passes, one of said rolls having a felt periphery for contact with the face of the film, means for .posing a drag on the rotation of the other roll, and means for lightly compressing said rolls onto the film.

6. In a machine of the class described, the combination with a film having a sound track thereon, and sound reproducing means through which said film travels, of means for tensioning said film in advance of said sound reproducing means, comprising a pair of rolls between which the film passes, the end portions of said rolls being annularly countersunk to avoid contact with the edge portions of the film, means for imparting a on the rotation of one of said rolls, and means for lightly compressing said rolls onto the film.

ABRAHAM SHAPIRO.

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