US1182486A - Yielding drive mechanism. - Google Patents

Description

W. L. HUDSON.

YIELDING DRIVE MECHANISM. APPLICATION man MAR. 3. 1915.

1,182,486. 7 Patented May 9,1916.

wInLIAML, HUDSON, or nLLIsBuR-e, NE YORK.

YIELDING DRIVE MECHANISM.

- Specification of Letters Patent.

iPatented May 2, 121 6.

Application filed March 3, 1915. Serial No. 11,833.

To all whom itmay concern: I p v Be it known that I, lVILLIAM L. Hnnson, a citizen of the United States, andresident of Ellisburg, inthe county of Jefferson and State of New York, have invented certain new and useful Improvements in Yielding Drive Mechanism, of which'the following is a specification. e a I This invention relates particularly to a drive mechanism such as is used in motionpicture machines, either those in which a film-strip is exposed, as ,ina camera, or those in which pictures are projected from a film-strip. v

In connection with the take-up reel of a motion-picture machine it is necessary to employ means for frotating the. reel con- ,stantly, and in order to insure that the rotation shall be sufficient to maintain the film under sufficient tension, while at thesame time compensation shall be made for the varying diameter of the roll of film on the reel, it is desirable to employ frictional yielding connections between the reel and the mechanism by whichit isrotated.

The object of the present invention is to provide simple and effective frictional connections between these parts and to provide for a convenient adjustment of the degree,

of friction in these connections, and the invention resides inthe novel construction for that purpose hereinafter described.

In the acompanying drawings :-Figure 1 is a side-elevation of a portion of a motion picture projecting machine-embodying the present invention, with parts shown in section; Fig. 2 is a view, on a larger scale, of the adjustable frictional connections between the driving-pulley and the shaft of the take-up reel, shown from the inner side of the pulley; and Fig. 3 is a sectional view on the line 3-3 in Fig. 2.

Theinvention is illustrated as embodied in a machine in which the film-strip 10 is guided and fed downwardly between two vertical guide-plates 11 and 12, the feeding movement being produced by pivoted feeddogs 13 which engage the perforations in the margins of the film, in a well-known manner. The feed-dogs are reciprocated by mechanism including a pitman lfiroperated by a crank-pin on a disk 17 at the end of a shaft 18 which is geared to the power-shaft 19 of the machine. This power-shaft is provided with a pulley 20 which is connected, by a belt 21, with a pulley. 22 connected with the shaft 23 by whichthetakeup reel 14 is supported and rotated, and accordingly the reel is rotated constantly whenthe feed-mechanism is in operation. I The film, after passingdownwardly between the guide-plates 11 and 12, passes beneath a fixed guide or abutment 25 which cylindrical in formand of a sufficient di- .ameter to preventthe film from being bent to a sharp angle in passing around it. From rection, to and over a similar fixed guide 26, and from the'latter it passes through the wall of the casing 15, between guide-rollers 2 1, and to the reel 14. Since the reel tends .mittently by the feed-mechanism, it will be apparent that at constantlyrecurringinter vals a certainamount of slack film willibe present between these instrumentalities. By means of the fixed guides 25 and 26, however, I dispose effectively of this slack film, while at the same time maintaining sufiicient tension on the film, as it is wound upon the take-up reel, to cause it to be wound closely. Owing to the resiliency of the film itself it tends, whenever slackened, to assume a smoothly curved form in those parts of it which, as shown in Fig. 1, extend straight between the guide-plates 11 and 12 and the guide 25, and between the latter and the guide 26. Accordingly, at each operation of the feed-mechanism the film which is de taken up by the reel is absorbed, so to speak,

the guide 25 the film passes, in a reverse diby this change'in the disposition of the film from a straight course to a curved course, and at the same time the slight friction of the film against the guides 25 and 26 is sufiicient to cause the slackness from passing freely around the guides and loosening the portion of the film which stretches between the guide 26 and the reel to such an extent as to permit the film which has already been wound from loosening upon thereel.

Since it is necessary, in order to insure close winding of the film, that there be a tendency to drive the reel always somewhat faster than is absolutely necessary to take up the film as delivered by the feed-mechanism, I have so proportioned the gearing and the drivepulleys as to tend to drive the reel at the maximum speed necessary, and have interposed yielding connections between the drive-pulley 22 and the shaft 23 to accommodate the'surplus movement of the driving-mechanism as the diameter of the roll increases. These connections are shown in Figs. 2 and 3. The pulley 22 is journaled loosely upon the shaft 23 and held thereon by a collar 27. The rim of the pulley is provided, on the inside, with sockets 28 which receive the ends of two leaf-springs 29. and 30, between which the shaft 23 is clasped, the resiliency of the springs causing them to grip the shaft with a certain amount of friction, so. that'when the pulley is rotated it tends to rotate the shaft also, but with a degree of force which is insufficient to cause injury to the film or the mechanism when the pulley rotates faster than bears against the spring 29, and by turning the eccentric the spring may be forced with more or less pressure against the shaft 23, thus varying the degree offriction by which thepulley and the shaft are coupled together. The eccentric is retained in its adjusted position by the friction'between it and the spring.

My invention is not limited to the embodiment thereof hereinbefore' described and illustrated in the accompanying drawings, but it may be .embodied in various other forms within the nature of the invention as it is defined in the following claims.

l. The combination, with a drive-shaft, of a pulley mounted on and rotatable with respect to the drive-shaft, and a pair of leaf-springs supported, at their ends, upon the pulley and between which said shaft is frictionally clasped.

2. The combination, with a drive-shaft, of a pulley mounted on'and rotatable with respect to the driveeshaft, a pair of leafsprings supported, at their ends, upon the pulley and between which said shaft is frictionally clasped, and adjustable means forregulating the pressure of one of said springs against the shaft.

3. The combination, with a drive-shaft, of

a pulley mounted'on and rotatable with respect to the drive-shaft, a pair of leafsprings supported, at their ends, upon the pulley and between which said shaft is frictionally clasped, and aneccentric carried by the pulley and engaging one of said leaf springs, the eccentric being rotatable to force said spring with a variable pressure against said shaft.

In testimony whereof, I aflix my signature in presence of two witnesses.

WILLIAM L. HUDSON.

Witnesses: V

'B. S. BEEBE, A. G. DAY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. 0.

Images