US2437997A - Winding device for cinematograph films and other applications - Google Patents

Description

March 16, 1948. A. M. B. CHARLIN 1 WINDING DEVICE FOR CINEMATOGRAPH FILMS AND OTHER APPLiCATIONS Filed Sept. '17, 1945 IN VENTO R A ND RE MARIE BERNARD cHARLm Patented Mar. 16, 1948 'WINDING DEVICE FOR UINEMATOGRAB-H FILMS ANDQTHER APPLICATIONS Andrltlar'ie Bernard Charlin, jMon'trouge, France Application September 17, 1945, Serial No. 616;88-1

in France April39, 1945 3 Claims.

It is known that in a cinematograp'h film projector, the film, after having passed in the projection mechanism, must be wound .ina magazine box designed for this purpose.

Since the winding speed varies uniformly from the start when the reel is empty, until the end when the reel is full, it is not possible to have the spindle of the winder driven direct by a gear coupled to the mechanism, butitis necessary to difficulties of manufacturing mechanical frictions are again encountered.

imperatively driven disk against which is placed a sheet of material having .a low coefficient of friction, then the reel presents at its centre a pass through the intermediary f a friction sheet metal dome cover intended to cap said hub, phng which Slips constantly so that the'speed f in such ,a manner that the'bottom of said dome winding shall be compatible with the speed of cover may remam a o the of y arrival of the film to the magnet of the hub, while its periphericfiange is It is Very dimcult to construct a friction cow pressed onto the sheet of material having a low phng which permits of obtaining a uniform 10 coefficient of friction applledon the disk of the tension in the film which is being Wound hub by the magnetic attraction of the magnet cording as the friction is more or less slippery, gf ggz gfig gi g giigiggg figigf m the tions in'the torque are obtained whichprejudice 2Q i the load F g i proportllon the correct winding and even sometimes entail a s :25 zi g g 5 the risk of straining the film which may at times y S Ve y W be pulled too violently which causes the risk empty reel which is driven by the friction cou- I pling tightened under the action of the magnet, of deteriorating its perforations restrained by e h f i ,t d f the unreeler of the projector. then t e r (2 ion is nex increase as a uric ion T d tm t t f thi f 1 0f the increase of the load due to the winding on O reme y s S a e P r 0 Ion of the so that the driving torque is ensured hem has been created which the Weight of throughoutthe functioning under optimum conthe reel by constantly increasing renders the Gimme torque Proportional to the Speed This device The invention moreover extends to various essentially constituted by a hub of fairly great other ehafaeterishes which appear in the den diameter lined with a suitable rubbing surface, tailed description which follows rotates at constant speed corresponding to the A f f embodiment of e Winding device g rea1 7e$t speed w ljeel Should at the conformable to the invention is represented. as ginning of the wlnding on. On said hub a reel '35 an example, in the attached drawing is mounted which is driven simply by friction by Figure '1 is a longitudinal section of the windthe hub, the friction being greater in proportion m device Without the reeL as the weight of the film is itself greater. This Figure 2 the side elevation f the reel. device gives good results on conditions that at Figure 34 a cross section of t reel, the start the weight is sufiicient to ensure a good 40 represents th reel 0F Figure 3 placed drive, the reel being empty. Unfortunately, by On t 1 ft, portj n of Figure increasing the weight of the carcass of the reel 4 reprsents t pjncue of t Winder and g to obtain this good drive, the moment of inertia the pulley driven t constant speed by the s of the reel is increased at the same time, sothat g mmechanism by means-belt 3, at the start here may form a l o e lo p of the '4 Spindle l rotates freely in bearings t and film Ow n o the rapid getaway 0f the P A-steel hub body 5 lspinned to the end of spindle l and to ay in the acceleration of the l. A mild steel disk 8 and a hub 9 of material reel. The reel then assumes a more and more correctly selected to have a low coeificient of rapid acceleration and resorbs said loop in a friction and non-magnetic qualities are secured more or less brutal manner, which again entails by means of screws I to said hub. The latter the risk of damaging the perforations. may, for instance, be made of metal having a This disadvantage can evidently be contended low coefiicient of friction, Bakelite or fibre. with by making a lighter reel, but by adding at A magnet I0, presenting a magnetic pole at the start a sufiicient friction effect to obtain a either end of its axis, is housed and held against correct drive; however, the disadvantages and 5 axial movement in said hub 9. Said magnet can advantageously be constituted by a small cylinder of nickel and aluminium base steel, said alloy presenting a great coercive force.

The reel utilized on the winder of Figure 1 comprises a steel hub H, constituted by a dome cover of stamped mild steel sheet and the outer edge of which is riveted on a disk 12 very light and very even,- which may be constituted by a plate of duralumin, sheet metal or even com pressed material, fibre, wood, etc.

An aluminium dome cover l3, riveted on hub II and centred by the flange of the hub forms the core on which the film I4 is wound. Said dome cover comprises parts or members, such as springs, slits, etc., permitting the hooking on of the end of the film. Holes are provided in said dome cover so as to be able to introduce the fingers to seize the reel full or empty.

In Figure 4 it is noticed that dome cover H exactly caps hub 9 and that the bottom of dome cover H is opposite magnet 10. There exists between the bottom of the dome cover and said magnet a slight air-gap which depends on the thickness of a sheet or plate made of a nonmagnetic substance having a low coefficient of friction the thickness of which is selected so that the magnetic field developed by the magnet and circulating according to the dotted line through steel dome cap H, steel plate 8 and the steel hub 6 may be sufiiciently powerful to determine at the start a 'sufilclently strong friction on the sheet or plate l5, in order to ensure a correct get-away of the reel at the moment of the starting up of the projector.

It is conceived that this get-away will be excellent since the moment of inertia of the reel. owing to its construction, is extremely reduced. In proportion as the film is wound onto core l3, its weight increases more and more, determining an increasingly greater force of friction between the steel dome cover II and the nonmagnetic hub 9, which thus ensures, by a correct calculation of the ratio of the diameters, a constant tension in the film by the unreeler of the projector. I

The winding device of the invention presents various other advantages. It facilitates the putting in place of the reel and its removal by the disappearance of the locking and of the driving dog, which are replaced by the magnetic field. On the other hand, the arrangement lends itself readily to an accurate, construction, nevertheless very robust, which permits of ensuring a perfect truing of the members in rotation and consequently an excellent winding on of the film, without the latter running the risk of rubbing unnecessarily against the edge of the reel as often happens in the usual arrangements.

By selecting correctly the materials with a low coefficient of friction of the hub 9 and of the plate I5, it is even possible not to provide any lubrication of the rubbing surfaces, which considerably simplifies maintenance. This winding device may be utilized not only for the normal 35 mm. film, but also for any other size.

It might likewise be utilized for the spooling of any substance other than film. For instance. it might be employed with the same advantage in the automatic machines for printing photographic prints on paper or the winding of delicate fabrics, such as silk or others and, in a general manner, wherever it is desired to wind any sort of strip presenting a certain fragility as the case happens in cinematography.

Various modifications might moreover be made in the example of embodiment described without exceeding the scope of the invention. In particular, the reel might be constituted in a different manner. Likewise, the magnet might be arranged in any suitable way in the hub fixed to the end of the driving spindle. I

I claim:

1. A winding device for cinematographic films comprising a Winding shaft, bearings supporting said shaft, driving means at one end of said shaft, a hub support fixed at the other end of said shaft, a disk made of magnetic material and a hub made of non-magnetic material having a low coefficient of friction fixed on said hub support, a plate made of non-magnetic material having a low coefiicient of friction applied on said disk, a magnet presenting a magnetic pole at either end of its axis housed inside said hub, a dome-shaped reel hub having a peripheral flange and being disposed on the hub of said shaft in such a manner that the bottom of said reel hub is maintained in spaced relation from the end of said magnet while said flange is forced against said plate by the magnetic attraction of said magnet on said reel hub, a disk secured to the outer edge of said flange, a reel body fixed on said reel hub, and means on said reel body for securing the end of the film to be wound on.

2. A winding device for cinematographic films according to claim 1, said hub support including a machined portion and a flange behind said portion, said plate comprising a washer, said hub made of non-magnetic material being supported on said portion, and means securing together said latter-mentioned hub, said washer and said disk to said latter-mentioned flange.

3. A winding device for cinematographic films according to claim 1, said reel body being cylindrical in shape, including means securing together said reel body and said reel hub, and said reel body being provided with openings to facilitate handling thereof.

ANDRE MARIE BERNARD CHARLIN.

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

UNITED STATES PATENTS Number Name Date 1,144,694 Delaney June 29, 1915 1,240,560 Gilmore Sept. 18, 1917 1,844,676 Owens Feb. 9, 1932 1,862,267 Honig June 7, 1932 1,984,778 Tross Dec. 18, 1934

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