US2939700A - Friction drive - Google Patents

Description

June 7, 1960 w. ENKELMANN FRICTION DRIVE 2 Sheets-Sheet 1 Filed Jan. 20, 1956 @@RCDCO CBICOC@ W. ENKELMANN FRICTION DRIVE June 7, 1960 2 Sheets-Sheet 2 Filed Jan. 20, 1956 5 Claims. (Cl. 271-23) This invention relates to apparatus for supporting and `feeding strip material such as motion picture film, and `more particularly to an improved strip transport which embodies a novel friction drive.

The present transport is somewhat similar to the film transport disclosed in Patent No. 2,146,170, entitled Film Supporting and Driving Means, issued February 7, 1939,

wherein sets of film feed rollers, driven from friction rollers, and idler rollers, around which roller film to be processed is looped, are carried on dependent, pendulumlike supports to permit suspension thereof in various lm processing solutions. t

Unit-@a sans 'Parent so In this patented apparatus,` and in other equipment of l this general nature, the friction drive rollers are rotatably supported on suitable framework at the open upper ends of the film processing tanks, the film feed and idler rollers associated with a given drive roller being suspended framework so as to accommodate downward movement `of the feed rollers out of engagement with thel associated drive roller during periods of excessive tension in the film. The axes of rotation of the associated drive, feed, and idler rollers in a given one of said set of rollers Vlie in a common vertical plane with the result that the point of tangency, or driving contact, of the drive rollers with the feed rollers is also in this plane. i. The peripheral driving thrust exerted by the drive roller on the feed roller, therefore, is directed along a line normal to such verticallplane and produces a moment about` the points of `attachment of the tie rods to the supporting frame. The moment produced` by this normally directed driving thrust, during operation of the equipment, causes the tie rods supporting the feed and idler rollers to swing in the direction of the thrust until the restoring moment of the tie rod support becomes suicient to overcome the driving thrust whereupon the support will swing back to or slightly beyond its normal position. The driving thrust then again becomes effective to swing the support. It is found, therefore, that during operation of the patented apparatus the tie rod supports for the feed and idler rollers oscillate back and forth with resultant undesirable `variations in film tension and non-uniform movement of the film. y

c A primary object Vof this invention is, accordingly, provision of a strip transport embodyingfriction drive apparatus of the class described which is free of the above-noted deficiencies.

Another object of the invention is the provision `of a strip transport embodying friction drive apparatus of the class described wherein the driving thrust between the driving and driven rollers does not give rise to any undesired oscillatory movement of the driven roller support.

Another object of the invention is the provision of a strip `transport embodying friction drive apparatus of the ICC class described wherein the support for the driven rollers is subject `to undesired movement in a given direction and wherein the driven rollers are contacted by the drive rollers at such points that the resultant of the driving thrust and the roller pressure is directed along a line of action normal to said direction so that undesired movement of the support in said direction by the driving thrust is substantially eliminated.

A further object of the invention is the provision of a transport of the class described which is especially suited to and adapted for the feeding of a `film strip through a series of film developing and washing solutions and drying cabinets. t

The above and other objects are attained in the present `transport by horizontally offsetting the axis of the driving or friction rollers from the vertical plane of Vthe dependent support which resiliently mounts the driven roller shaft. The points of driving contact of the driving rollers with the driven rollers will, therefore, also be offset from the vertical plane of the dependent driven roller support, and the driving thrusts on the driven rollers will have downwardly inclined lines of action passing through said points `and directed to one side of the support. The` pressure between the driving and driven rollers gives rise to forces on the latter rollers havingl downwardly inclined lines of action directed to Athe other side of the support.` s

i The amount of offset or displacement of the driving `roller axis is made such that during normal operation of the apparatus, the resultant of the above forces on the driven rollers will be directed vertically downwardly substantially in the vertical plane of the driven roller support so `that the aforedescribed tendency of the latter to oscillate under the action of the driving thrust is effectively eliminated.

While the foregoing discussion andthe ensuing description relate Vto a ilm developing machine, it will, be 'appreciated that numerous other types of apparatus may incorporate friction drive arrangements which possess the above noted deciencies andn which, accordingly, the present invention may be employed to advantage. c

The `invention may be best understood by a reading of the following detailed description thereof in conjunc- -tion with the accompanying drawings wherein:

Fig. 1 isa fragmentary/elevation in section of a film processing machine incorporating a friction di'ive embodyingthe features of this invention; y

Fig. 2 is a section taken along line 2 2 of Fig. 4l;

Fig. 3 is a partial Vsection taken substantially along line 3-3 of Fig. l, parts being` broken away for the :sake of clarity; and l i Fig 4 is a section taken along line 4-4 of Fig. 3 illustrating the off-center driving arrangement embodied in this invention and the force components with which this invention is concerned.

Referring now to these drawings, there is `illustrated a film processing machine including, inthe well known manner, a series of solution tanks arranged in side by side relation and through which a negative film strip is adapted to be successively passed for developing, washing `and fixing of the film. Only three of these tanks, indicated a't 10, 10 and 10 have been illustrated. Intermediate ones 10 and 10 of the tanks are spaced a distance, as shown, for reasons to be presently described,

Associated with each tank is a film feed and supporting means, generally indicated at 11 to -be shortly more' fully described. `The several tanks and the associated film feed and supporting means are identical and, therefore, only the tank 10 and its corresponding means 11 will be described. t -Tank 10 includes side walls 12 `along `theupper edges of which extend connecting frame members 13. Above thetank is ahorizontallyvextending frame comprising a pairof `yhollowdrive frames'14 and 15 which, as will'be seen, support the several means 11. These frames extend the lengthof the several tanks, at opposite sides thereof, and are'supported in normal operative position a distance above the upper ends of the tanks by a hydraulic lift device 16 disposed -in the aforementioned space between lthe intermediate tanks and 10'. This lift device includes a stationary cylinder and movable piston having a piston rod 17 fixed fat its upper end to cross frame pieces 418 extending between and rigidly joined to the drive frame l14- and l5. The arrangement is such that the frames '14 and 15 maybe raised from their normal operative position, shown, to elevate the several means 11, and the `film carried thereon, out of the tanks.

The present Vinvention is primarily concerned with the film feed and supporting means `11 which will now -be described.

[Extending between the vertical inner side walls Y14' and 15 of the drive frames 14 and 15 is a horizontal shaft'20 having its right hand end, as viewed in Fig. 2, journaled in a lbearing 22 in the right hand drive frame ld'5 and its left hand end journaled in and extending a `distance beyond a second .bearing 22 in the left. hand drive frame 14. This extending left hand end of the 'shaft 20 rigidly mounts a sprocket 24 for driving en- .gagem'ent with a sprocket chain 26 (Fig. l) which vis similarly kengaged with drive sprockets in the other of the means l11, for simultaneous driving of the shafts in the several means 11. Idler sprockets 28 may bev alternated with the drive sprockets, as shown, .to obtain increased driving vengagement of the chain and driving sprockets. This chain #26 is adapted to be driven from 'a motor, Ynot shown, and the lower run of the chain may move in'an oil bath contained in the left hand drive tframe,14, as shown. To permit access to the drive frame vinteriors the frames may be provided with =hinged panels or doors, also as shown.

IFixedon shaft 20, for rotation with the shaft, are a pair of spaced friction drive rollers 30 provided about `their peripheries with suitable friction material 32. The improvements of the instant invention are particularly concerned' with the means for suspending film feed rollers, generally indicated at 34, and idler rollers, generally indicated at 36 included in each means 11, in operative relationship below the drive -rollers 30.

The improvedroller suspension means of this yinven- .tion comprises a pair of vhanger rod supports including hanger rods 38 aixed at their -upper ends, ina,rnanner to be presently described, to horizontal, inwardly extend-A ing .plates 40 secured to the undersides of the'drive frames .14 and15. As-seen-in Fig. 2, each of the hanger rods depends fromv its `respective supporting plate v40 in a plane spaced slightly inwardly of the adjacent tank side wall,:and, as shown in Fig. l, the pair of vtie rods are disposedin a, common, transverse vertical plane horizontally .olset from the friction roller shaft 20 in'a direction opposite to the direction of movement of the ,lower peripheralpportion of the frictionvrollers 30 forreasons to be Vpresently described.

:Asmost clearly illustrated in Fig.V 3, 'each hanger rod 38is tubular-,in crosssection andjhasv an `upper threaded `.end.portion.42 which :extends through a suitable opening'in the respective one -of the supporting plates :40. Apair of nuts 44 threaded onthe rods at opposite-sides .of -the platesserve-to attach the rodsto theplates. VRigidly fixed on the lower extremities of the rods 38 are bearing blocks -46 which support opposite ends of a lower roller shaft 48 mounting the idler rollers 36. The idler rollers Vare.rotatablymounted on the lshaft 48 and may be retained in axialposition thereon by means of collars 50.

The lm -feed rollers 34 are mounted on an Upper -l'ller shaftv 52 and retained-in axial position thereon by tioned patent.

Hfeed rollers 34, are mounted for vertical movement on the hanger rods. Y

Slidably mounted on the hanger rods below -the slides 62 are collars 66 and Awashers 6 8, the latter abutting the under sides of lthe slides 62. The QppOsed end faces of the collars and washers are formed with annular seats 70 and 72 for seating opposite ends of coil compression springs 74. Slidably received in the bores of the tubular hanger rods are adjusting shafts 76 the lower en ds of which mount transverse pins 78 whose opposite ends kextend through slots 80 in the rods and into the reSpeGtive collars 66 so that the latter are fixed to their shafts 7 6 for axial movement therewith.

T -he upper end off each Yshaft 76 isexternally threaded at :8,2 and received, in a threaded axial bore in an adjusting sleeve 84. Thelower end Y of each adjusting ,sleeve is peripherally .grooved to form an annular seat 86 and :a reduced annular y,extension 88V the latter being rotatably Areceived .Within the upper end of the respective hanger rod so that the upper end surface of the latter Vslidably bears lon the annular seat S6. The arrangement isfsuch -that the axial :positions `of theadjusting shafts 76 in the .hanger rods, andzhencethe v'axial .positions of the ,collars 6 6 on rthe -rods, may be adjusted -by rotation of the ad- -justingsleeves 84 to adjust the normal vertical position .of the `film feed rollers 34. `The .film feed rollers are .resiliently `supported in such .normal position by the coil compression springs `7.4.

Fromlthe description thus far, it will Abe seen that lthe idlerV roller shaft 48 is vfixed lagainst vertical movement on the llower ends `of the hanger rods 38 while the feed rollershaft SZandthe -feed rollers 34. thereon. are resiliently s uppmtedonthe rods. Y

vA web 190, which in theillustrative embodiment of the invention is ,a negative riilm strip but which may take varying forms depending .onthe nature ofthe apparatus ,incorporating ,the-present yfriction drive arrangement, is delivered atta constant rate from a supply reel, not shown and then passed vin succession around the feed and `idler rollers of theseveral meansv 11, in the manner illustrated herein :amd-described in .greater detail in theaforemenyFilm -is -thus lead from therlastforvrig'ht hand, feed rollerin tank 10' to theiirst, or left hand, feed roller in 1 tank 10 and the run of ilm'leading olf the last -feed roller in :tank 10 .passing to' the first feed rollersin tank v10 andthence'to ltherollers in successive Ysolution tanks Iand drying cabinetsfnot shown.

As-,shown Zin Eig. Vcertain of ithe feed rollers '34 are alined with thedrive rollers '30 and in use of the apparatus, the adjusting sleeves 'S4-are so set that these feed rollers will ybe .resiliently urged, through the medium of .the springs 7 4, into engagement with the drive rollers with the desired `force so' that the feed rollers maybe frictionally driven bythe drive rollers to move `thelilm in the direction indicated. As describedindetail in `said prior patent, successive -drive rollers -30 in succeeding ones of the `lilm suppcrtingandffeeding means 411 lmay be of slightly increasing Vdiameter so as to maintain aV desired minimum tension in the fln1,:the resilient supporting iof the feed rollers providing the means for establishingga predetermined :maximum film tension in the apparatus. However, it will be apparent that the features .of this inventionmaybe equally well applied in appara-Y tus `not utilizing suchardiiferential driving arrangement;

Referring now to Fig. 4, there are-illustrated the vari- Vousforce components withwhich this invention is concerned. It will be seen from that figure, that the periphcries of the friction drive rollers 30 and the aligned feed rollers 34, at their zone of peripheral contact, move in a transverse direction of the vertical plane of the hanger rods. Further, the friction drive rollers are offset in that direction from the vertical plane so that a plane passing through the axes of the upper roller shaft 52 and friction rollers is inclined at an acute angle in said transverse direction from the vertical plane. The points of tangency, `or driving contact', 92, of the feed rollers with the driving rollers will be disposed intermediate the latter vertical plane and thevertical plane passing through the axis of the friction drive rollers. The tangential driving force or driving thrust, Fd, exerted on the feed rollers at these points will be directed along a downwardly inclined line of action, inclined to plane of the rods 38, rather than along a line normal to the last-mentioned plane as is the case where, as in the patented apparatus, the drive and feed roller axes are in the same vertical plane.

The feed rollers 34 have applied thereto a resultant force F, acting upwardly along the axes of the hanger rods which will be equal to the difference between the upward force exerted by the suspension springs 74 and the downward forces represented by the mass of the feed rollers 34 and feed roller shaft 52 and the tensions in the runs of film between the feed and idler rollers. Since said mass remains constant and is directed along the axes of the hanger rods, further discussion thereof will be omitted, the force F, being hereinafter considered as the differential between the upward force ofthe springs 74 and the downwardly acting tensions in the film.

The upward force Fr on the feed rollers will have a radial component directed along a line of action extending through the centers of the drive and feed rollers tending to urge the feed rollers into frictional engagement with the drive rollers. The resultant equal opposing or reaction force acting on the feed rollers is designated as Fp. The feed rollers, therefore, have applied thereto the tangential driving force Fd and the radial force Fp, that is the pressure of the drive rollers on the feed rollers.

Considering now the hanger rods 38, which may be regarded as being, in a sense, pivoted at a point 94 co'rresponding to the point of attachment of the upper ends of the rods to the plates 40 since any oscillation of the rods will occur substantially about this point, it will be seen that the forces Fd and Fp will be applied thereto through the point 52 which is the axis of the feed roller shaft.

The present invention proposes such a horizontal displacement of the feed and drive rollers that for the normal operating values of the forces Fd and Fp, the resultant F of these latter two forces will be directed downwardly substantially in the vertical plane of the hanger rods, as shown. When this situation exists, of course, the hanger rods 38 will not be subject to any unbalanced moments tending to oscillate them about the point 94.

It will be apparent that variation in the tension of the film will result in a variation in the roller pressure Fp and cause the resultant force F to shift in one direction o'r the other from its normal disposition in the plane of the hanger rods. Such shifting of the resultant force F would, of course, give rise to an unbalance moment on the rods and produce some oscillation thereof. Because of the relatively greater magnitude of the other forces involved, however, the variation in film tension will generally not be sufficient to cause appreciableshifting of the resultant F, especially where means of the character described in said prior patent are employed for maintaining the film or the other from its normal disposition in the plane of the hanger rods. Such shifting of the resultant force F would, of course, give rise to an unbalance moment on the rods and produce some oscillal tion thereof. Because of the relatively greater magnitude of the other forces'involved, however, the variation in film tension will generally no't be sucient to cause appreciable shifting of the resultant F, especially where means of the character described in said prior patent are employed for maintaining the film' tension constant within given limits.

The preferred form of the invention disclosed herein is only illustrative in nature, it being apparent that numerous modifications in design and arrangement of parts of the invention was made with the scope of the following claims.

I claim:

l. A transport for strip material such as motion picture film, comprising a horizontally extending frame, a pair of horizontally spaced, vertical hanger rod supports xed at their upper ends to and depending below said frame, a pair of upper and lower, horizontal roller shafts supported at opposite ends on said supports, at least one strip guiding and supporting roller on each shaft, a fric tion drive roller in :forced peripheral driving contact with the upper strip roller journalled on said frame for rotation about an axis substantially parallel to said shafts, means for driving said friction roller in one direction of rotation whereby to drive said upper strip roller, the peripheries of said friction roller and upper strip roller at their zone of peripheral contact moving in a transverse direction of a vertical plane passing through the upper shaft when said friction roller is driven in said one direction, and said friction roller being offset in said transverse direction from said vertical plane so that a plane passing through the axes of the upper shaft and friction roller is inclined at an acute angle in said transverse direction yfrom said vertical plane whereby when the tangential driving force and radial force exerted on said upper strip roller by said friction roller have predetermined values, 'the resultant of said forces acts longitudinally of said supports and oscillation of the latter by said forces is avoided.

2. Ille subject matter of claim l wherein each of said supports comprises a single hanger rod, said roller shafts' being located in the vertical plane of said hanger rods.

3. A transport for strip material such as motion picture fil-m comprising a horizontally extending frame, a pair of horizontally spaced, vertical hanger rods xed at their upper ends to and depending below said frame, a lower horizontal roller shaft fixed to the lower ends of said rods, an upper horizontal roller shaft, slides secured to opposite ends of said upper shaft and slideably mounted on said rods, said shafts being located in the vertical plane of said rods, atleast one strip guiding and supporting roller on each shaft,` a yfriction drive roller in peripheral contact with the upper roller journalled on said frame fo-r rotation about an axis parallel to said shafts, abutment means on said rods below said slides, springs acting between said abutment means and slides for biasing the latter upwardly along said rods whereby to urge said upper strip roller against said friction roller, means for driving said friction roller in one direction of rotation whereby to drive said upper strip roller, the peripheries of said friction roller and upper strip roller at their zone of peripheral contact moving in a transverse direction of said vertical plane when said friction roller is driven in said one direction, and said friction roller being offset in said transverse direction from said vertical plane so that a plane passing through the axes of the upper shaft and friction roller is inclinedV at an acute angle in said transverse direction from said vertical plane whereby when the tangential driving force Aand radial force exerted on said upper strip roller by said friction roller have predetermined values, the resultant of said forces acts longitudinally of said rods and oscillation of the latter by said forces is avoided.

4. The subject matter of claim 3 including means for adjusting said abutment means along the rods to vary the force ofv contact of saidupper stript-roller with saidV friction roller.

5. -A transportifor str-ip material-'such as mot-ion picture film comprising a horizontally extending frame, a pair of vertical, hollow hanger rods fixed atVtheir-upper ends to and :depending below said-frame, a`1owe1` horizontal roller shaft supported at opposite ends on the lower ends of said rods, a plurality 4of ylower strip supporting and guid ing rollers on said shaft, an upper horizontal roller shaft, slide means slidably mounting opposite ends of said upper roller vshaft on :said rods adjacent the upper ends of the latter, a plurality of upper strip supporting and guiding rollers on said upper roller shaft, said shafts being located in -the vertical plane of saidrods, a collar slidable on .each rod below said'slide means, a coil compression spring `encircling-each rod between and abutting at opposite ends the'adjacent collar land slide means, a friction driving roller journalled on -said frame :and peripherally engaging atleast one lofrsaid upper strip rollers for References Cited in the -ile of this patent UNITED STATES PATENTS 2,l23,44 5 Van Leuven July 12, 1938 2,146,170 Brenbarger et al. Feb. 7, 1939 2,435,298 Van .Leuven Feb. 3, V1948 2,584,293 Sachs et al. Feb. 5, '1952

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