US2529075A

US2529075A - Winding mechanism

Info

Publication number: US2529075A
Application number: US782970A
Authority: US
Inventors: Wilfred P Dawson
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-10-30
Filing date: 1947-10-30
Publication date: 1950-11-07
Anticipated expiration: 1967-11-07

Description

Nov. 7, 1950 W. P. DAWSON WINDING MECHANISM Filed Oct. 50, 1947 INVENTOR: Wilfred P. Dawson,

. ATTORNEY.

Patented Nov. 7, 1950 UNITED STATES PATENT OFFICE 6 Claims.

My improvement pertains to a mechanism used for the purpose of winding up motion-picture films on reels, although the device may equally well be used for other analogous purposes. The device, in its basic form, includes two elements, the driving element and the driven element, the two elements being brought into a frictional engagement to a degree depending upon the load upon the driven element, that is, the element supporting a roll of film. The fact is that the said load varies in practice. While the engagement and the means to bring about the engagement are perfectly satisfactory where the load is considerable, said means to effect the frictional engagement are not always satisfactory when the load is slight. It must be, also, remembered that, in the initial stages of the winding operation, it is necessary to overcome the inertia of the reel itself, and that the lag of the initial rotary movement of the reel will become immediatelyapparent in the deficiency of tension in the winding of the film. As a means to cure the defect, the makers of the present-day equipment suggest the use of an oil of heavy viscosity for the parts to be frictionally engaged, in the belief that the viscosity ofthe oil would provide a sufficient drag on the driven part for the purpose of imparting to it a rotary movement. This expedient, however, proved of little value. It is for the purpose of overcoming said objections and deficiencies as above set out, also to eliminate the need of heavy oils that I have improved the conventional driving mechanism which is now employed' As a result, I have produced a mechanism in which the tension upon a film is substantially uniform during the whole process of wind ing it up. More specifically, the mechanism improved by me will permit the winding of a, film with sufiicient tension in the initial stages of the winding process.

in meeting the problem, I am using certain additional means in conjunction with the basic elements already used in the conventional devices. I shall now describe my improvement with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a winding mechanism with parts supporting it broken oh and disclosing the location of my improvements with respect to the load-sustaining element therein; Figure 2 is a longitudinal sectional view on line 22 of Figure 1; Figure 3 is a transverse sectional view on line 3-3 of Figure 2; Figure 4 is a transverse sectional view on line 4-4 of Figure 2; similar numerals refer to similar parts throughout the several views.

In describing my improvement, I shall start with a bracket composed of a wall I I which may be a part of a motion-picture projecting mechanism, the wall including a drum-like boss Ill. The latter is provided with an internal cylindrical aperture for support of a cylindrical liner I2 axially fitted into said boss and retained in place by means of a set screw 49. Pressed into the liner endwise, is a sleeve 13 extending outwardly from said liner and supporting thereon a pulley M which is the driving element of my device and which includes along hub l5 skirting said sleeve 13 and sloping downwardly in the di rection of boss l0. 1

The hub above referred to terminates in a hard ring l8 which bears against a plurality of ball bearings 19 retained within a race 2| in the inner end of liner [2. On the side remote from the boss, the pulley includes a circular, recessed portion l6 axially disposed therein and defined by an annular shoulder IT. A provision for lubricating the abutting surfaces of hub l5 and sleeve l3 upon which the pulley rotates is made in said hub by having a hole 5|] drilled therein for admission of oil as shown in Figure 2, the hole being closed by an oiling plug 4-1.

To describe the driven element, I shall start with the shaft 22. The shaft includes a portion 23 of a reduced diameter for support of a film reel which is shown in dotted lines indicated by numeral 26, and is provided with an arm 24, swivelled at 25, the arm serving as a means of securing the film against displacement once it is mounted upon said reel. At its junction to portion 23, said shaft 22 includes a collar 21 made in the form of a truncated cone, the collar being supported by roller bearings 28 a key marked 52 serves to secure the collar to the shaft to cause the collar to rotate with said shaft. It will be noted that the respective axes of the rollers flare outwardly from the longitudinal axis of the shaft 22. As a result of that, unless otherwise restrained, the shaft would have a tendency to move longitudinally outwardly from said bearings. An end disc 29, secured to the reduced portion 23 of the shaft, restricts the movement of the shaft inwardly-that is, in the direction away from the reel 26. The end 3| of the shaft opposite to that which supports the film is secured to a cup-shaped head 32 by means of a set screw 48. The latter includes an axially disposed hub 34 rising from the bottom of the cup-shaped formation, the hub being bored axially and threaded as shown at 33 in Figure 2 for reception of the above-said. threaded end 3,! of shaft 22. Two

the clutch plate 40 is keyed to the shaft 22 by means of a key 5| so as to rotate therewith.

To support the weight of the head said shaft 22, at that part of its length where it passes through the center of pulley H3, is provided with ball bearings, said ball bearings including an .annular member 43 keyed to the shaft, a plurality of balls 22, and a stationary race 45, this being held within the sleeve It as best shown in Figure 2. i

To conclude the description of the mechanism, I wish to add that a coiled spring 45 is disposed around the shaft 22 between the annular member 43 on the shaft and between the clutch plate 3%. I wish, also, to add that the belt by means of which pulley It may be rotated is shown by numeral 46. I

Having described my above mechanism, I shall now describe its operation:.Pulley I4, driven by belt 66, imparts a rotary movement to head 32 by means of the aforesaid clutch plate 40 and the floating, annular member 4| combined therewith. As the clutch plate is keyed to shaft 22, the rotation of the plate will, naturally, cause the rotation of the shaft. In'orde to effect a frictional engagement between the pulley and the clutch plate 40 through the annular'member 4i thereon, some provision is needed to bring the clutch plate and the annular member into intimate contact with the faceof the recess [6 in the pulley, preferably a contact under pressure, Normally, this is; brought aboutby the weight of the film on reel 28, said weight causing a slippage outwardly of the shaft 22, as the cone-shaped ring 21 on the shaft tends to slipin that direction on the outwardly-flaring rollers 28. v l However, as indicated in the beginning of the specification, the weight of the reel in the initial. stages of winding up a film is too slight tobringthe ring M and the clutch plate 40 into a sufficiently frictional contact with said pulley, and here it is, where the improvement devised by me performs its function. The coiled springs 3.8

within apertures 35 in the head 32 carriedby the threaded end of shaft 22 bear against the clutch plate 30 by means of balls 39 exerting enough forceupon the clutch plate and the, annular ring M to cause .a sufficient frictional engagement thereof with the pulley 1. 1- so that the rotation of the pulley is transmitted to the shaft, supplying enough tension for; the winding operation of the film. In case of need, the pressure of springs 33 may be. adjusted by means of screws 3].

Subsequently, when the load increases, it is the weight of the load that will bring abouta sufficient frictional engagement of the clutch plate with the pulley. When-the load upon the shaft 22 is relieved, the coiled spring 45, hearing against the centralpart of clutch :plate at as best shown in Figure 2, will shift the plate outwardly in the.

direction of the head 32.

It will be'obvious ,thatsome changesmay be; made in the:construction. of. my. device with- 1 adapted to carry at one end a film reel, a collar adjoining said end of the shaft and being in the shape of a truncated cone in a frictional engagement with said rollers, a clutch plate, axially "slideable on the shaft for engagement with the face of the depression in the pulley and rotating thereon with said shaft, a cup-shaped head on the other end of the shaft, the head having a plurality of cylindrical apertures parallel to the shaft, a ball within each aperture bearing against the .clutch plate, each ball being backed up by a coiled spring within the aperture, and an adjustable screw threaded against said spring.

2. A tensioning device of the kind described including a stationary, tubular support, a beltdriven pulley mounted thereon for rotation, one face of the pulley having a central depression defined by a shoulder alongthe rim thereof, a shaft axially disposed within the tubular support and having at one end means for support of a film reel, a cone-shaped collar keyed upon the shaft,

outwardly flaring roller bearings within the tuclosing the aperture on the side of the clutch plate, the balls bearing against the plate under the pressure of. the springsto bring the plate into. engagement with the recessed face of the pulley, the shaft being adapted to move axially partly out of the flaring-out roller bearings under the weight of the load and the shaft at that end, and a coiled spring on a shaft to urge the return of the shaft to its normal position on release of said load.

3. A tensioning device of the kind described comprising a bracket includinga horizontal cylinder, a tubular member axially connected to one end of said cylinder, a belt-driven pulley rotating on said tubular member, the pulley having a circular depression in one side thereof said depression being defined by a shoulder around the rim of the pulley, an outwardly-flaring bearing at the other end of the cylinder, a shaft axially-disposed in the cylinder, a substantially conicalcollar on the shaft and within said bearing, 'the'collar when the shaft is loaded having a; tendency to slip axially outwardly of said bearing, a clutch plate mounted on the shaft, the.

end .and adjoining the clutch plate, a plurality ofapertures in the head symmetrically disposed around the axis thereof and parallel thereto, a, ball in, each aperture to bear against the plate,

spring means in each aperture to, urge the ball,

outwardly into contact with the clutch plate, a screw threaded from outside into each aperture for adjustment of the tension of the spring within, and a spring coiled about the shaft and bearing against the clutch plate from the side remote from the head to move the shaft on release of the load in the direction of said head to re turn the collar to its normal position within the outwardly flaring bearing.

4. A tensioning device of the kind described including a belt-driven pulley rotating on a tubular horizontally disposed member and forming the driving element, a shaft axially disposed within the tubular member and adapted to carrya load on one end, a cone-shaped collar on the shaft at said load end, a cone-shaped bearing at the outer end of the tubular support for engagement with said collar, a spring acting upon the shaft to keep the collar normally within the bearing, but yielding to the outward pull of the shaft under the weight of the increased load thereon, a clutch plate mounted on the shaft, adjoining the pulley, and adapted to slide axially thereon to a limited length but keyed to the shaft for rotation therewith, the clutch plate being adapted to slide into a frictional engagement with the pulley on the axial shift of the shaft outwardly of the conical bearing under the load on the shaft, a cup-shaped head mounted on the opposite end of the shaft, the head including a plurality of apertures in the direction of the clutch plate, each aperture being closed by a ball and containing a coiled spring urging said ball into abutment with said plate, to bring said plate into frictional engagement with said pulley preliminary to the axial shift of the said shaft under the load thereon.

5. A tensioning device of the kind described including a tubular supporting member, a pulley axially mounted for rotation thereon, an outwardly flaring bearing within the tubular support at the end remote from the pulley, a shaft axially disposed within the tubular support and having at one end means to support a load, a conical collar on the shaft and within the outwardly flaring bearing, the shaft being capable of axial shifting outwardly of said bearing, a clutch plate on the shaft facing one side of the pulley for 6 engagement therewith, spring means to prevent axial shifting of the shaft till the weight of the load thereon overcomes the tension of said spring, a head at the other end of the shaft, the head being provided with a plurality of apertures parallel to the shaft, a ball closing each aperture on the side of the clutch plate, a spring behind each ball to maintain it in contact with the plate and to push the plate into engagement with the pulley preliminary to the shifting of the shaft under the load.

6. A tensioning device of the kind described including a tubular supporting member, a pulley axially mounted for rotation thereon and having on one side a depressed central portion defined by a shoulder along the rim thereof, an outwardly flaring bearing within the tubular support at the end remote from the pulley, a shaft axially disposed within the tubular support and having at one end means'to support a load, a conical collar on the shaft and within the outwardly flaring bearing, the shaft being capable of axial shifting outwardly of said bearing, a clutch plate on the shaft facing one side of the pulley for engagement therewith, a floating friction ring along the marginal portion of the plate and fitting into the depressed central portion in the pulley, spring means to prevent axial shifting of the shaft till the weight of the load thereon overcomes the tension of said spring, a head at the other end of the shaft, the head being provided with a plurality of apertures parallelto the shaft, a ball closing each aperture on the side of the clutch plate, a spring behind each ball to maintain it in contact with the plate and to push the plate into engagement with the pulley preliminary to the shifting of the shaft under the load.

, WILFRED P. DAWSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,377,112 Boylan May 3, 1921 1,398,680 Clayton Nov. 29, 1921,