US1906186A - Film-drawing device for cinematographic apparatus - Google Patents

Description

25, 1933. E 5 Q DEVHLLE FILM DRAWING DEVICE FOR CINEMATOGRAPHIC APPARATUS Filed April 19, 1929 2 Sheets -Shee't l April 25, 3 E. s. c. DEVILLE 1,906,186

FILM DRAWING DEVICE FOR CINEMATOGRAPHIC APPARATUS Filed April 19, 1929 2 Sheets-Sheet 2 Eye 5 B B I I u IJ D D Cl A Wu 4' W Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE ETIENNE SAIN'IE CLAIRE DEVILLE, OF PARIS, FRANCE, ASSIGN OR TO SOCIETE DES ETABLISSEMENTS GAUMONT, OF PARIS, FRANCE, A CORPORATION OF FRANCE FILM-DRAWING DEVICE FOR CINEMATOGRAPHIC APPARATUS Application filed. April 19, 1929, Serial No. 356,583, and in France May 21, 1928.

In the various apparatus such as cameras, film printing apparatus, developing machines, lanterns, and the like, the film is drawn forward by claws or by toothed rollers.

The said claws or rollers engage in perforations in the film when in contact with the latter, and thus the film is given a continuous or an intermittent motion.

The edges of the film are thus subjected to a considerable stress, these edges being already weakened by the perforations, so that the film is rapidly put out of use after it has been employed for a certain number of times in the screen lantern.

The present invention relates to a filmdrawing device which has essentially for its object to reduce the stresses and wear of the film, and chiefly during its travel upon the feeding roller and the retaining roller, which parts are found in all cinematographic apparatus, by balancing the tensions at the input and the output ends of said rollers.

The said device esentially comprises a roller which is mounted in an elastic manner, for

instance upon a lever oscillating under the action of an adjustable spring, upon which roller the film travels before engaging the toothed driving roller also employing a sec ond roller upon which the film travels after 80 leaving the toothed roller. This second roller is quite similar to the first in apparatus adapted for continuous travel of the film, but in apparatus employing intermittent travel, the said roller is positively controlled and is combined with a pressing roller which acts upon the edges of the film.

In order to reduce the wear of the perforations, it is preferable to employ at the same time a smooth drum of larger diameter which acts in conjunction with the toothed roller and is loosely rotatable on a shaft parallel to the roller shaft, it being so disposed that the film will be in contact with the said drum upon a certain length of the periphery, while at the same time the film is drawn forward by the teeth of the driving roller. This complementary device thus assures the engagement of the film perforations with the teeth, and their withdrawal, which operations now take place without the abrup motion by which the film is torn or broken.

The following description with reference to the accompanying drawings which are given by way of example shows the manner in which the said invention may be carried into effect.

Figure 1 shows the film-drawing device used in an apparatus adapted for intermittent travel.

Figure 2 shows the corresponding arrange ment in an apparatus adapted for continuous travel.

Figures 8 and 4 show the combination of a smooth drum with the toothed film-drawing roller.

The cinematographic film supplied by the upper bobbin, which may comprise the special device described in the French patent in applicants name No. 256,173 dated the 12th of May 1928, entitled: Braking device for cinematographic films, passes over a roller I mounted on an axle which is secured to the lever 5 oscillating under the action of the spring 7, the film being drawn forward by the toothed drum 2.

If the apparatus operates by intermittent action (Figure 1), that is ifthe part of the film travelling in the film gate and lighted by the illuminant is displaced in an intermittent manner between two free loops, the shaft of the roller 3 which is rotated by mechanical means, is provided with actuating means opcrating by adjustable friction, and the adhe sion of the film is obtained by a pressing roller 4 acting upon the edges of the film.

The spring 7 and the friction actuating device of the roller 3 are so adjusted that the tension of the film at ab will be substantially equal to. the tension at 0d, so that the pressure of the teeth upon the perforations will be moderate and the duration of the film greatly increased.

The same arrangement is applicable to the toothed retaining roller.

If the apparatus is of the continuous travel tivpe, and is provided with a smooth filmrawing roller whose motion is made regular by a flywheel, as specified in the French Patent No. 600,401 to A. Poulsen and A. C. G. Petersen dated the 7th of July 1925, the tensions a?) and cal can be balanced by mounting the second roller, which freely rotates, upon an axle secured to a lever oscillating by the action of an adjustable spring.

Figure 2 shows such a device, consisting of a roller 3 which is mounted loose on an axle secured to a lever 6 oscillating under the tension of a spring 8 and so regulated that the tension at ad is practically equal to the tension at ab.

An improvement which is applicable to both devices above mentioned is shown in Figure 3, and by its use the film is less subject to wear or damage. In this arrangement, there is added to film-drawing roller 2 a drum 9 of the proper diameter, whose circumference is tangent to that of the toothed roller at the middle point of the envelopin arc. The said drum, which has a very light weight, is loose on its axle.

This arrangement has the advantage of mechanically controlling the release of the teeth from the perforations of the film and of preventing the edge of a perforation in contact with a tooth from remaining in contact during a certain rotation of the smooth part of the roller and then suddenly escaping under the effort of traction, which is one of the chief causes of damage.

In this manner it becomes ossible to drive the film with a single row 0 teeth cooperating with a single row of perforations, thus leaving free the whole part of the film hithertooccupied by the second row of perforations, and clear to the edge of the film. This arrangement is shown in Figure 4, in which the film has been turned downwards in order to properly show the construction.

As shown in Fig. 4, the guiding member 9 preferably consists of two distinct rollers, one engaging the film near the sprocket 2, and the other engaging the film along the unperforated edge thereof. These two rollers are keyed on a common axle.

Thus added width 10 may be used for various designs, wording or titles, or in acoustic films for the sound records adapted for reproduction.

It is also possible to eliminate this width if it is not to be used, whereby the cost of the film will be appreciably reduced.

Obviously, the said devices are suscept ble of all necessary modifications in detail, without departing from the principle of the invention.

What I claim is 1. A film feeding mechanism for motion picture apparatus comprising a toothed film drawing roller adapted to engage the driving perforations of the film, and a smooth uiding roller of larger diameter than said m drawing roller, adjacent to it, and hav ing a tangent plane which is also tangent to the film drawing roller along the same straight line, whereby the film is so guided as to need but a single row of driving perforations.

2. A film feeding mechanism for motion picture apparatus comprising a toothed film drawing roller adapted to engage the driving perforations of the film,-a smooth guiding roller of larger diameter thansaid film drawing roller, adjacent to it, and having a tangent plane which is also tangent to the film drawing roller along the same straight line, whereby the film is so guided as to need but a single row of driving perforations, and means for equalizing the tensions of the film at the input and at the output ends of said film drawing roller.

3. A film feeding mechanism for motion picture apparatus comprising a toothed film drawing roller adapted to engage the driving perforations of the film, a smooth guiding roller of larger diameter than said film drawing roller, adjacent to it, and having a tangent plane -that is also tangent to the film drawing roller along the same straight line, whereby the film is so guided as to need but a single row of driving perforations, two oscillating levers mounted on either side of the film drawing roller, rollers at the ends of said levers for supporting the film and at least two springs adapted to act on said levers respectively for causing the film to be applied against the film drawing roller, whereby the tensions of the film on each side of the film drawing roller are equalized.

4. A film feeding mechanism for motion picture apparatus comprising a toothed film drawing roller adapted to engage the driving perforations of the film, a smooth guiding roller of larger diameter than said film drawing roller, adjacent to it, and having a tangent plane that is also tangent to the film drawing roller along the same straight line, whereby the film is so guided as to need but a single row of driving perforations, an oscillating lever, a roller at the end of said lever, a spring adapted to act on said lever for causing the film to be applied upon the film drawing roller, a driven roller positively connected to the film drawing roller and a roller for applying the film against said driven roller whereby the tensions of the film on either side of the film drawing roller are equalized.

5. A feeding mechanism for films having only one series of driving perforations comprising a film drawing roller, one series of teeth upon said roller adapted to engage the driving perforations of the film, and a smooth guiding roller of larger diameter than said film drawing roller, adjacent to it, and having a tangent plane which is also tangent to the film drawing roller along the same straight line, where y the film 1s soguided as to need but a single row of driving perforations.

In testimony whereof I have signed this specification.

ETIENNE SAINTE CLAIRE DEVILLE.

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