DE613149C - Arrangement for attaching film strips to the spool core - Google Patents

Description

The invention relates to an arrangement for

Attachment of film strips to the spool core, which is a special training of the end of the film used in conjunction with a special design of the coil core.

There are already film attachments of this type become known, including those that use a special fold at the end of the film strip, which can be folded into a

to the coil core slot spreads like a barb. Fastenings are no longer new either a more or less radial one provided with a barb-like cavity Have a slot into which the end of the film is inserted. It's at its outer end bent over, so that this bend is in the cavity when it is inserted into the coil slot of the slot spreads and is locked against pulling out.

Also z. B. film mounts are known in which the end of the film in a concentric Groove is inserted, making fish-. scale-like cutouts in corresponding Spread the openings.

All of these types of attachment can only be released by destroying the end of the film strip.

The fastening according to the invention is, however, easily detachable and can be used several times; the individual parts are so large and simple that they can be handled can be done with certainty even in complete darkness. Still, it will be a safe one Connection achieved.

The new connection consists in that the insertion tongue through a constriction is delimited from the rest of the film strip and the spool core is a trapezoidal, opposite the winding direction has tapered opening, the dimensions of which are those of the insertion tongue are adapted. The coil is expediently designed so that an annular A cavity for receiving the insertion tongue is created. The film tongue can have lateral embossing obtained for stiffening, which serve to guide in the annular cavity and stiffen the tongue in the transverse direction.

The invention is shown in the drawing in several exemplary embodiments, and although show *

Fig. Ι the film spool with inserted film end in plan view,

Fig. 2 shows a cross section of the coil according to Fig. Ι on an enlarged scale,

Fig. 3 film ends of trapezoidal and hexagonal shape,

Fig. 4 film ends of octagonal and circular shape,

Fig. S Film ends of elliptical shape with lateral stiffening and guide ribs.

A second tube b is inserted concentrically in the outer tube α ^{1 of} the film reel α. ^{This creates # 2} between the inner surface

of the outer tube α and the outer surface b ^{1 of} the inner tube b the annular cavity c. The outer necks a ¹ has a trapezoidal opening d, the edges d ¹ , d ^{2 of} which are parallel to each other and to the central axis of the coil. If the end of the light-sensitive unexposed film / is to be fastened to the spool, the end / ¹ , which can also be trapezoidal in shape according to Fig. 3, for example, is pushed towards the opening d, slides into it, and moves along the annular cavity c until the film edge / ² abuts the film spool tube α. The edge d ¹ must therefore be at most equal to the greatest width of the insertion tongue. The point / ^{3 of} the film / is then also in the ring channel c. Behind the surfaces f , the film / has opposite constrictions / ⁵ , the distance between the points / ^β advantageously corresponding to the smallest width d ^{2 of} the trapezoidal opening d. If the film / is now drawn towards this edge d ² , the film end f ¹ slides with its lateral surfaces / ⁷ along the inner wall a ^{2 of} the outer tube a ¹ until the edge / ³ meets the edge / ⁸ at the corner α ^{4 of} the trapezoid creates and prevents the film from being pulled further /.

In Fig. 3 the opening d and the end of the film is shown in development. The differently designed film ends shown in FIGS. 3 to 5 also act in the same way in the new fastening. Furthermore, the ends Z ^{1 of} the film / can be provided with ribs etc. like indentations or impressions / ⁹ to reinforce and secure against shearing off of the film by the edge d ² .

Claims (3)

Patent claims: i. Arrangement for attaching film strips to the spool core, in which the unintentional pulling out of the strip from the insertion opening is prevented by protruding parts of the insertion tongue, characterized in that the insertion tongue (Z ¹ ) is separated from the rest of the strip by a constriction (/ ^{5) and} the coil core has a trapezoidal opening (d) which is tapered against the winding direction and whose largest width is equal to or greater and whose smallest width is smaller than the largest width of the tongue. 2. Film reel according to claim 1, characterized in that in the interior of the coil tube (α ¹ ) provided with the trapezoidal opening there is a second tube (b) of such a diameter that an annular cavity (c) is formed between the two tubes the insertion tongue (Z ¹ ) receives. 3. Film strip according to claim 1, characterized in that the tongue (Z ¹ ) to be inserted into the trapezoidal opening (d) of ^{the reel has embossments (/ 9} ) which stiffen it and guide it in the annular cavity (c). 1 sheet of drawings