US 3695534 A
In a film transport system employed for automatic motion picture film processing, film feed spools or rollers which are spring mounted to the hub portions thereof so as to be deflectable in response to increased film tension into peripheral driving engagement with a resilient overdrive roller. The film feed spools have a central, tubular core or hub adapted to be mounted on a shaft, an inner roller body ball-bearing mounted on the hub for free rolling movement, and an outer roller body against which the film rides which is supported on the inner roller body by annular spring units comprising at least five relatively short and stiff arcuate leaf springs disposed in regularly spaced relationship, the leaf springs being arranged for radial deflection relative to the axis of the roller to permit shifting of the roller into engagement with the resilient drive roller, but being resistant to torsional displacement or "windup" so that when film tension is relaxed, release from the drive roller is substantially instantaneous, involving substantially only translational movement of the outer feed roller body relative to the drive roller and not requiring a combination of both rotational unwinding movement and translational movement.
Description (OCR text may contain errors)
United States Patent Treise [541 FILM FEED MECHANISM  Inventor: John C. Treise, 10436 Ruffner Ave,
Granada Hills, Calif. 91344 22 Filed: March 9,1970
21 Appl.No,: 17,376
521 US. Cl ..242/ss.01  Int. Cl. ..B65h 75/00  Field of Search ..242/55.()]
 References Cited UNITED STATES PATENTS 3,380,678 4/1968 Feasey et al ..242/55.0l 3,498,556 3/1970 Thomas et al. ..242/55.01 3,369,765 2/1968 Jensen ..242/55.0l
Primary Examiner-Stanley N. Gilreath Assistant Examiner-Milton Gerstein Attorney-Albert L. Gabriel  ABSTRACT In a film transport system employed for automatic mo- Oct. 3, 1972 tion picture film processing, film feed spools or rollers which are spring mounted to the hub portions thereof so as to be deflectable in response to increased film tension into peripheral driving engagement with a resilient overdrive roller. The film feed spools have a central, tubular core or hub adapted to be mounted on a shaft, an inner roller body ball-bearing mounted on the hub for free rolling movement, and an outer roller body against which the film rides which is supported on the inner roller body by annular spring units comprising at least five relatively short and stiff arcuate leaf springs disposed in regularly spaced relationship, the leaf springs being arranged for radial deflection relative to the axis of the roller to permit shifting of the roller into engagement with the resilient drive roller, but being resistant to torsional displacement or windup so that when film tension is relaxed, release from the drive roller is substantially instantaneous, involving substantially only translational movement of the outer feed roller body relative to the drive roller and not requiring a combination of both rotational unwinding movement and translational movement.
2 Claims, 6 Drawing Figures PATENTEDnma I972 SHEET 2 0F 2 FIG.6
JH/v 6! lease A'rromey FILM FEED MECHANISM BACKGROUND F THE INVENTION Film transport systems presently employed for mo tion picture film processing feed the film in a continuous length through a series of stations including tanks which contain film processing solutions, rinsing solutions, fixing solutions, washing solutions and the like, and one or more drying chambers. It is current practice to provide a plurality of film feed spools that are aligned on a single horizontal shaft at the top of each tank, with a corresponding group of aligned spools on another horizontal shaft proximate the bottom of the tank, and for the continuous strip of film to be fed in a series of loops over these upper and lower film feed spools so that the loops extend into the solution in the tank. In order to regulate the film speed and to make the film tension as uniform as possible throughout such a continuous film transport system, it is current practice to employ what is commonly known as a demand drive, wherein a come-along or pacer drive at the output end of the system determines the speed of film movement, and an elongated overdrive roller at each station is engaged by individual spring-mounted film feed spools when the film tension becomes too great in the region of the individual spools so as to overcome .the biasing force of the spool springs and pull the spools into peripheral contact with the overdrive roller; relaxing of the film tension when the film is thus speeded up proximate the individual rollers permitting the roller springs to shift the rollers back out of enagement with the overdrive roller. Such a film transport system is shown and described in US. Pat. No. 3,380,678, issued Apr. 30, 1968 to Feasey et al., for a Web Transport System.
While such conventional film transport systems are far superior to earlier direct drive systems wherein the film was primarily sprocket driven, they nevertheless fall far short of providing the desired equilibrium condition of generally uniform film speed and tension throughout the transport system. Thus, in actual practice, film speed and tension both vary materially at various points in the drive system, the feed spools tending to remain in driving relationship with the overdrive roller too much of the time, which tends to overstress the springs of the film feed rollers, resulting in substantial breakage thereof. The resulting uncertainty in operation and down time of the equipment results in increased operating expense and slower production rates.
Such problems in conventional demand drive film transport systems appear to be caused primarily by the structure and the mode of operation of the individual spring-mounted film feed rollers. According to current practice, the film feed spools or rollers each have a pair of axially spaced spring hub units made of polypropylene including a central bushing which is the actual bearing member engaged on the shaft, an annular rim radially spaced from the bushing and generally coaxial therewith, and usually two, but sometimes three, long, thin, flexible leaf springs of spiral, involute configuration joining the rim to the hub. These leaf springs that are conventionally employed each extend through a curvature of more than one-half revolution where three of them are employed, and each extend generally through more than a full revolution where two of them are employed, and this circumferential length coupled with the spiral, involute configuration and thin flexible nature thereof cooperate to provide a windup clock spring angular displacement operation which is deliberately designed into the spools to allow angular displacement of the peripheral portions of the spools relative to the hub portions for the purpose of reducing stress on the film. The polypropylene hubs which are integral with the springs do not provide a good antifriction relationship with the shaft, and the substantial hub-shaft friction as the film tension increases helps to cause this windup type of action.
While this torsional windup mode of operation of prior art film feed spools was heretofore considered to be an important characteristic for proper film transport operation, the applicant has determined that, to the contrary, it is a factor which introduces considerable irregularity and uncertainty into the film feed system. Springs of this type require wide gapping from the overdrive roller, on the order of from about .040 inch to about .100 inch, in order to obtain release of the spring rollers from the overdrive roller. This type of spring also requires the use of knurled peripheral edges of the feed rollers for adequate driving engagement with the overdrive roller. When film slack arrives as a result of the overdriving, disengagement of the driven rollers from the drive rollers is delayed because of the necessity to unwind, because of the gripping tendency of the knurled peripheries, and also because of the relatively weak disengaging spring force of the long, slender springs, and the net result is that with such prior art spring rollers there was a tendency for them to continue being driven to a substantial extent even after the film tension has been released by overdriving, and there is a general tendency throughout the system for the driven rollers to be kept in driving relationship with the overdrive Rollers too much of the time. This introduces unequal stresses on'the springs and on the film, tending to tear up the springs, with considerable spring breakage usually resulting.
With the long, spiral, involute spring configurations a large proportion of the spring stressing tends to occur proximate the connections of the springs with the hubs and the body portions of the spools, which further add to the spring breakage problem. Most of the breakage in such prior art film feed spools is observed to occur proximate the junctures where the ends of the spring leaves connect with the more solid portions of the spool.
The long, thin, spiral construction of conventional film feed spool springs results in substantially completely independent operation of the springs at op posite sides of each spool; i.e., if a load tending to tilt the spool axis is applied to one side of the spool so as to deflect the corresponding spring, there is substantially no reaction force from the spring at the opposite side which would tend to stabilize the spool. Thus, when 35 mm. spools are employed in the processing of 8 mm. and 16 mm. film, the narrower film invariably crowds one side of each spool, thereby tipping the spools to a substantial angle off of the shaft axis, and thereby. in-
troducing a binding tendency into the system where a long series of such tilted spools is present.
SUMMARY OF THE INVENTION In view of these and other problems in the art, it is a general object of the present invention to provide a novel construction for film feed spools or rollers employed in a film transport system for motion picture film processing, together with a novel mode of operation thereof, wherein the operative engagement with and disengagement from the overdrive rollers in response to respective increases and decreases in film tension is precise and uniform throughout the system, resulting in a high degree of uniformity in film speed and tension throughout the system, with the entire film feed system functioning in a good equilibrium condition wherein there is a minimum of stress on both the film and the film feed spools or rollers.
A more specific object of the invention is to provide a novel film feed roller of the character described having a tubular core or hub adapted to be mounted on a shaft, an inner body portion of the roller that is mounted on the hub by rollable bearing means, preferably ball bearings, for free spinning movement, and a flanged outer roller body against which the film rides, and which is supported on the inner roller body by a pair of axially spaced, annular spring units comprising a plurality of leaf springs, preferably at least five in number, disposed in regularly spaced relationship about each annular spring unit, the individual leaf springs of each spring unit being of outwardly bowed, arcuate configuration, preferably being arcs of a circle in their relaxed positions, and being relatively short and stiff, extending in the circumferential direction only approximately one-quarter turn or less. These leaf spring members, by virtue of the aforesaid structure thereof and also in combination with the rollable bearing antifriction free-spinning mounting of the spools relative to the shaft, respond to increased film tension on the spool or roller by confining the resulting roller movement into engagement with the overdrive roller to be substantially entirely translational movement without any material or substantial torsional displacement or windup." Thus, when film tension is relaxed, release of the film feed spool or roller from the overdrive roller is substantially only translational movement, and does not involve the conventional combination of both rotational unwinding movement and translational movement, whereby release is substantially instantaneous.
A further object of the invention is to provide, in a film transport system for motion picture processing, film feed rollers of the character described wherein the novel configuration of the roller springs enables the film feed rollers to be disposed much closer to the overdrive rollers than in conventional apparatus of this type, preferably in the range of from about .010 inch to about .030 inch, to assist in providing the desired substantially instantaneous response to changes in film tension.
A still further object of the invention is to provide film feed rollers of the character described which, by virtue of the novel configuration of the leaf spring members embodied therein, is extremely durable, with a minimum of spring breakage resulting from the fact that the novel arcuate spring configuration causes most of the spring flexing to be in the central portions of the springs, with minimal deflection proximate the connected ends of the springs.
Another object of the invention is to provide film feed rollers of the character described wherein the novel configuration of the spring members in the rollers enables much stronger springs to be employed than can be used with the conventional spring configuration, on the order of ten or more times the strength of conventional springs, thereby further improving the quickness of response to changes in film tension.
Another object is to provide film feed spools or rollers of the character described wherein, as a result of the novel configuration of the leaf springs embodied therein, application of a greater film tension force to one side of a roller than to the other will cause a spring reaction force on such other side, thereby tending to stabilize the roller and keep the roller axis from tilting to any substantial extent relative to the axis of the shaft upon which the roller is mounted, thereby substantially eliminating binding where relatively wide rollers, as for example 35 mm. rollers, are employed in the processing of relatively narrow film, as for example 8 mm. or .16 mm. film, which shifts to one side of the roller in operation.
Another object of the invention is to provide novel film feed spools of the character described wherein the spring means employed in the spools permits such positive engagement of the peripheral flanges of the spools with the overdrive rollers that knurled peripheries are not required for proper operation of a film transport system employing the present film feed spools or rollers.
A still further object is to provide a film transport system embodying a series of novel film feed spools of the character described, wherein the novel leaf spring configuration and mode of operation in the spools results in positive, brief overdrive contacting of the spools with the overdrive rollers, with predictable and regular driving force, whereby excellent uniformity in film tension is retained throughout the system in a preferred range of from about 602. to about 10 oz. of film tension for 35 mm. film, and whereby the entire system stays in tune with a high degree of equilibrium throughout. The system functions so uniformly with a set of the spring feed rollers of the present invention at the top of each station, that it is found in practice that solid spools or rollers can be employed at the bottom rack of each station rather than the usual spring rollers that are required at the bottom, and also that a fixed bottom rack can normally be employed instead of the conventional weighted, vertically shiftable elevator.
Further objects and advantages of the present invention will appear during the course of the following part of the specification, wherein the details of construction and mode of operation of a presently preferred embodiment of the invention are described with referance to the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one station of a motion picture film processing plant embodying the film feed spools or rollers of the present invention in the upper rack of the station.
FIG. 2 is a vertical section taken on the line 2-2 in FIG. 1.
FIG. 3 is an enlarged, perspective view illustrating a film feed spool embodying the present invention.
FIG. 4 is an axial section taken on the line 4--4 in FIG. 3.
FIG. 5 is a side elevational view of the spool shown in FIGS. 3 and 4 in its relaxed condition, or condition of repose, wherein the leaf spring members thereof are substantially unstressed.
FIG. 6 is a view similar to FIG. 5, wherein increased film tension on the spool has shifted the outer body of the spool downwardly relative to the inner body against the biasing force of the leaf spring members to the position of engagement of the spool with an overdrive roller.
DETAILED DESCRIPTION FIGS. 1 and 2 illustrate one of the stations in a film transport system for motion picture film processing which embodies film feed spools or rollers according to the present invention. Thus, as best shown in FIG. I, the station includes a film processing tank 10 containing a film processing solution 12. An upper rack assembly generally designated 14 includes a pair of generally parallel, vertical plates 16 and 18 supported on opposite sides of the film processing tank 10, with a pair of vertically spaced, parallel, horizontal support bars 20 and 22 rigidly connected between the spaced plates 16 and 18.
A drive motor 24 is attached to the plate l6 and is connected in driving relationship through appropriate gearing to a transverse. horizontal. driven shaft 26 rotatably supported by suitable bearing means on the plates 16 and 18, the shaft 26 having a chain drive sprocket 28 affixed thereto adjacent to the plate 16.
A lower rack assembly 30 including a pair of spaced, generally vertically arranged plates 32, is suspended from the upper rack assembly 14 by means of a pair of spaced, vertical rods 34 which are integrally connected at their lower ends to the respective. plates 32 and at their upper ends to the fixed transverse bar 22 of the upper rack assembly 14. The lower rack assembly 30 includes a fixed, transverse, horizontal shaft 36 supported at its ends on the respective plates 32, upon which a plurality of spring film feed rollers 38 according to the present invention are mounted, six of the film feed rollers 38 being shown in FIG. 1. Disposed immediately below the rollers 38 is an overdrive roller 40 which is resilient, the overdrive roller 40 being rotatably mounted in suitable bearings on the plates 32, and one end portion of the shaft of the overdrive roller 40 extending through the corresponding plate 32 and having a driven sprocket 42 fixedly secured thereto directly below the drive sprocket 28. A. drive chain 44 is engaged over the sprockets 28 and 42 so as to continuously drive the overdrive roller 40 during operation of the film transport system. The overdrive roller 40 is positioned so that its surface is within a preferred spacing of from about .010 inch to about .030 inch from the peripheral edges of the film feed rollers 38 in the positions of repose, or the relaxed positions, of the rollers 38. The spring rollers 38 are adapted to shift transla tionally downwardly into driving engagement with the overdrive roller 40 upon an increase in the film tension over the individual rollers, in the manner illustrated in FIG. 2, so as to increase the translational speed of the film at that point in the system so that the film will move smoothly and uniformly at the speed dictated by the come-along or pacer at the final end of the film drive, such speed generally being on the order of about 100 feet per minute.
A further film transport assembly'46 is disposed ad- 5 jacent to the bottom of the film processing tank 10. In
the illustrations of FIGS. 1 and 2 this transport as sembly 46 is shown as an elevator-type assembly which is weighted and is vertically slidably shiftable for automatic adjustment of the length of the film loops. However, it is to be understood that the film feeding action of the spring feed rollers 38 according to the present invention is so smooth and uniform that in many instances the vertically shiftable elevator type bottom transport assembly 46 is not necessary, and the bottom transport 46 can be rigidly positioned relative to the upper and lower rack assemblies I4 and 30 that are disposed above the solution 12.
The weighted elevator assembly 46 that is shown proximate the bottom of the processing tank 10 includes transversely spaced, generally vertical plates 48 that are joined together by a support bracket 50, with a transverse horizontal shaft 52 extending between the plates 48. A plurality of rollers 54 are rotatably mounted on the transverse shaft 52, in this case five of the rollers 54 being shown, with the continuous strip of film being looped between the upper rollers 38 and the lower rollers 54 so that a series of loops of the continuous film strip are immersed in the film processing solution 12, the number of such loops determining the amount of time that the film is subjected to the solution 12 at a given film transport speed.
The film feed rollers 54 are shown as solid rollers since the film feeding action of the spring rollers 38 according to the invention in the upper part of the station is so uniform and smooth that the spring rollers that are usually required at the bottom of the station are not generally necessary.
The elevator assembly 46 is vertically slidable on a pair of spaced, parallel, vertical track rods 56 which extend downwardly from a support bridge 58 at the top of tank 10, and a vertical guide rod 60 rigidly connected to the support bracket 50 of the elevator assembly 46 extends slidably through the center of the bridge 58 and has a handle 62 at its upper end for manual shifting of the elevator assembly 46. A weighted plate 64 is attached to the bottom of the elevator assembly 46 for applying the desired tension to the film.
The film strip 66 that is beingprocessed in the film processing tank 10 is shown coming into the station in a lead-in portion 68, and is shown leaving the station in a pull-off portion 70 which is moving at a speed determined by'thecome-along orfpacer at the output end of the system.
Referring now to FIGS. 3 to 6 of the drawings, in these figures details of construction of the presently preferred film feed rollers 38 according to the invention are illustrated. Thus, a filmfeed roller 38 which is constructed in accordance with the present invention includes a generally rigid tubular core or hub 72 adapted to be engaged upon the transverse shaft 36 that is shown in FIGS. 1 and 2, the core or hub 72 having an outwardly directed annular flange 74 at its righthand end as viewed in FIG. 4.
The roller has a generally rigidl, tubularinner body 76 having a pair of coaxial tubular end flanges 78 pro jecting from its ends so as to define a pair of inner, radially oriented annular shoulders 80 of substantial radial depth, and a pair of shallow outer annular radially oriented shoulders 82.
An annular array 84 of ball bearings is engaged axially between the hub flange 74 and the opposed inner shoulder 80 of the inner body 76 at the right-hand side of the roller as viewed in FIG. 4, this array 84 of ball bearings being radially engaged between the tubular core or hub 72 andthe inner body flange 78 at the right-hand side of the spool as viewed in FIG. 4.
Similarly, an annular array 86 of ball bearings is disposed adjacent to the left-hand side of the spool as viewed in FIG. 4, being retained axially between the corresponding inner shoulder 80 on the inner body 76 of the roller and a retainer ring 88 mounted on the lefthand end of the tubular core or hub 72 as viewed in FIG. 4, the array 86 of ball bearings being engaged in the radial direction between the tubular core or hub 72 on the inside and the corresponding tubular flange 78 of the inner roller body 76 on the outside.
The roller 38 also includes a generally rigid outer body 90 which is spaced radially outwardly from the inner body 76 and in the un-stressed ,condition of repose of the roller is coaxial with the inner body 76. The outer roller body 90 is notched on the inside proximate its ends to provide axially outwardly facing, radially oriented annular shoulders 92 which are radially aligned with the respective outer shoulders 82 on the inner body 76 of the roller. The outer roller body 90 also includes radially outwardly extending annular flanges 94 which define the sides of the outer roller body as viewed in FIG. 4, or the axial end portion of the outer body of the roller. The outer peripheral edges of these annular flanges 94 are adapted to be intermittently engaged by the overdrive roller 40 shown in FIGS. 1 and 2, and the operation of the present invention is such that it is found these outer peripheral edges of the flanges 94 need not be knurled as is required on conventional film feed spools. The film is adapted to loop over the spool 38 between the flanges 94, and if desired the spool may be provided with a beaded resilient pad 96 against which the film rides.
The inner and outer roller body members 76 and 90, respectively, may be made of any desired generally rigid material which is impervious to the chemical action of the solution 12 in the tank as shown in FIG. I, such a polystyrene or other generally rigid plastic material.
The annular spring units 98 according to the invention are preferably each molded as a unitary structure of a resilient plastic material such as polypropylene or the like. These annular spring units each include a circular inner hub 100, a circular peripheral portion 102, and a plurality of regularly spaced spring leaf members 104 which are each connected as their inner ends to the circular hub 100 and at their outer ends to the peripheral portion 102.
A pair of these spring units 98 is employed in each of the rollers 38, the spring units being frictionally engaged in opposite sides of each roller 38 with the hub portion 100 being frictionally engaged over the inner body flanges 78 against the shoulders 82 of the inner body, and being engaged in the notches in the ends of the outer body 90 against the outer body shoulders 92.
The resiliency of the material of which the spring units 98 are composed enables the simple assembly procedure for assembling the outer and inner roller bodies of merely frictionally engaging the spring units 98 between the inner and outer roller bodies on opposite sides thereof as best shown in FIG. 4.
Preferably five or more of the leaf spring arms or members 104 are regularly spaced between the hub and peripheral portions and 102, respectively, of each spring unit 98. Each of the leaf spring members 104 is of inwardly concaved, outwardly bowed arcuate configuration, preferably being substantially an arc of a true circle. Each of the leaf spring members 104 is connected to the outer peripheral portion 102 of the spring unit 98 by a connecting body of material so that the outer end of the leaf terminates in slightly radially inwardly spaced relationship to the outer peripheral wing 102, the leaf extending from this point substantially tangentially relative to the outer peripheral ring 102, and then curving arcuately inwardly to a connection with the inner hub portion 100 at a substantial angle relative to the hub 100. Each of the leaf spring members 104 extends preferably approximately only onequarter of a turn or less about the annulus of its respective spring unit 98.
In a presently preferred embodiment of the invention which has proved satisfactory in experimental operation, the hub part 100 of each spring unit 98 has an outside diameter of approximately one and one-half inches, the peripheral part 102 of each spring unit has an inside diameter of approximately 2-3/ I 6 inches, five of the leaf spring members 104 are regularly disposed between these inner and outer annular parts 100 and 102, respectively, of the spring units, each of the leaf spring members 104 having a radius of approximately 5 1 inch, and having a total length of approximately 3/l6 inches.
The leaf spring members 104 employed in the present invention are considerably stronger spring members than the long, slender, spiral or involute springs employed in similar prior art devices, providing a static spring reaction force to film tension on the order of about ten times the reaction force of conventional spiral or involute springs. Thus, in a static test of a spring roller 38 according to the invention as described above, a total of approximately 2-56 lbs. deflecting force was required for a spool outer body deflection of about .030 inch. Considerably more than one-half of this force was required to deflect only one side of the spool, indicating that where the force is applied over the spring unit at one side of the spool, as by narrow film, there is a considerable stabilizing reaction force by the spring unit at the other side of the spool.
It has been found in experimental practice with the present invention, that the combination of the rollable bearings, preferably the annular arrays 84 and 86 of ball bearings, and arcuate leaf spring arms 104 of the spring units 98 of the character defined in detail hereinabove, substantially completely eliminates windup or clock spring action in the spools during the operation thereof. It is further found in the operation of spools according to the invention that the leaf spring members 104 of the character described flex substantially entirely in their central portions, with minimal deflection proximate the ends thereof, thereby greatly extending the life of the springs and consequently of the spools.
In general, it has been observed in experimental operation of film transport systems embodying the present film feed rollers that the entire system is maintained in excellent state of tune, with a high degree of equilibrium throughout the system, so as to provide generally constant film speed and tension.
While the instant invention has been shown and described herein in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention.
1. In a web transport system of the type wherein an elongated, tensioned, longitudinally moving web is looped over a resiliently deflectablefeed roller rotatably mounted on a shaft, with a drive roller disposed adjacent to the periphery of the feed roller and intermittently engageable in driving relationship therewith pursuant to variations in feed roller deflection in response to variations in web tension; a web feed roller which comprises a generally rigid inner annular body rotatably mounted on said shaft, an outwardly flanged, generally rigid outer annular body over which the web rides disposed in generally concentric, spaced relationship about said inner body, a pair of axially spaced, generally annular arrays of springs disposed between said inner and outer bodies so as to resiliently support the outer body on the inner body, each of said annular arrays including a plurality of symmetrically arranged leaf spring members each having an inner end and an outer end, and means connecting said inner and outer ends to said inner and outer bodies, respectively, said leaf spring members being of outwardly convexed, arcuate configuration such as to allow resilient translational displacement of the outer body relative to the inner body without substantial relative torsional displacement for intermittent engagement thereof with the drive roller in response to variations in web tension, a generally rigid hub mounted on said shaft and located concentrically within said inner body, and rollable bearing means rotatably supporting said inner body on said hub for free spinning movement.
2. Apparatus as defined in claim 1, wherein said rollable bearing means comprises a plurality of axially spaced, annular arrays of ball bearings.