DE1285293B - Film take-up device of a photographic camera - Google Patents

Description

The invention relates to the film winding device of a photographic camera for perforated film, in which the film take-up spool forming a tongue with a slot running approximately parallel to the coil axis for receiving the beginning of the film and a retaining cam at the edge for engagement is provided in a perforation hole.

In a known film winding device of this type the tongue of the coil core through an incision slightly inclined towards its axis severed. On the inside of the tongue a cam is arranged so that it can engage in a perforated edge of the film. The slot has a domed one Cross-section on. This curvature of the slot is opposite to that of the film Curvature tendency inherent in the previous position in the cassette. At the The threading of the film pushes the film, which is inevitably somewhat bent in the slot to the front surface of the holding cam, which is perpendicular to the coil axis. It requires hence additional manipulations to bring the film over the holding cam. In the case of the structural design known per se, the film cannot, however, either release from the retaining cam by itself. Rather, it becomes more and more in the same with Zug depressed. The increasing rewind force due to the resistance of the holding cam therefore usually leads through the tightening and the associated sliding over one another of the turns of the film spool in the cassette for scoring on the exposed Movie. The rewind force increases so far under these conditions that the Ripping out perforation.

With conventional cameras, threading the film in the slot of the take-up reel and the attachment to the retaining cam in general considerable difficulties that can arise if the film is not carefully detached from the spool, and if this is not noticed, the valuable recording material will be lost can lead.

To overcome these difficulties, there is also a two-part Film take-up reel for axially parallel feeding of the film into a clamping slot of the spool for the purpose of frictional holding of the beginning of the film. at This known coil, the cylindrical bobbin has two diametrically located concave recesses. On her face is a U-shaped fitting attached, whose U-legs lie in the diametrical recesses of the coil. The ones fitted into the concave recesses complement the bobbin overlying U-legs of the shaped piece, the coil into a circular cross-section. The beginning of the film is after the axis-parallel insertion between the spool and the U-leg held by clamping. With this type of non-positive fixation of the beginning of the film it is necessary to move the film overcoming considerable frictional resistance between the bobbin and one leg of the molded piece attached to the front to push in. In addition, this process is made more difficult by the fact that the clamping leg Extends well beyond the center of the coil, which is a prerequisite for a workable Clamping effect is. The invention is based on the object of a film take-up device of the type mentioned above, avoiding the disadvantages mentioned above To train systems in such a way that the insertion of the film is made much easier.

This object is achieved according to the invention in that the in the area of the slot located holding cams on its side facing the center of the reel has a sliding surface which intersects the reel axis and is inclined against the same.

The invention is illustrated below with reference to the drawing using an exemplary embodiment explained. It shows F i g. 1 shows a cross section through the film spool near the holding cam, F i g. 2 is a side view of the coil perpendicular to the coil slot, FIG. 3 a View of the coil in the direction of the coil slot, F i g. 4 one in the spool slot Introduced beginning of the film and F i g. 5 the inserted into the reel slot and with The beginning of the film snapped into place at its perforation.

The hollow cylindrical bobbin 1 is on both of its end faces limited by coil flanges 5. The coil has a protruding from the end face 5, Tongue 2 running parallel to the bobbin axis and at a distance from the jacket of the bobbin on. The coil jacket is flattened in the area of the tongue. The one between the flattened Coil shell 6 and tongue formed slot 3 is several times wide. ter than the film thickness. The tongue 2 ends in front of the center of the coil, while the flat surface 6 extends almost to the other end face 5 of the coil 1. The free end of the tongue 2 'is to form a wedge-shaped extension 3' of the Slot 3 pointed. The retaining cam 4 is arranged at a distance next to the tongue 2. On its side facing the center of the coil, it has a side that intersects the coil axis and against the same inclined sliding surface 4 '.

However, nothing stands in the way of arranging the retaining cam below the tongue 2 as well . In this case, the tongue must have a recess in the region of the retaining cam 4 in order to enable the film edge to slide over.

The circular segment-shaped tongue complements the cross section of the coil a circular area, whereby they are on the long side 2 "facing the retaining cam 4 is cut.

Conveniently, the film take-up reel is through a single one Plastic molding formed.

In some cases it can be useful that on the coil diametrically to the film holding device consisting of tongue 2, flat jacket 6 and holding cam 4 a second identically constructed device is provided. Claims: 1. Film take-up device of a photographic camera for perforated film which the film take-up spool forming an approximately parallel to the spool axis running tongue with a slot for receiving the beginning of the film and a marginal one Holding cam is provided for engagement in a perforation hole, d a. -Through characterized in that the holding cam (4) located in the region of the slot (3) its side facing the center of the bobbin intersects and counteracts the bobbin axis has the same inclined sliding surface (4 '). 2. Film take-up device according to claim 1, characterized in that the free tongue end (2 ') is formed a wedge-shaped extension (3 ') of the slot running parallel to the coil axis (3) is pointed.

3. Film winding device according to claim 1 or 2, characterized in that that the retaining cam (4) is arranged at a distance next to the tongue (2).

4. Film winding device according to claim 1 or 2, characterized in that that the retaining cam (4) below which has a recess in its area Tongue (2) is arranged (not shown). 5. Film take-up device after a of the preceding claims, characterized in that they are through a single Plastic molding is formed.

6. Film winding device according to one of the preceding claims, characterized in that the tongue (2) is cut on one longitudinal side (2 ") is.

7. Filrnaufwickeleinrichtung according to any one of the preceding claims, characterized in that on the coil diametrically to the alas tongue (2), flattened jacket and holding cams (4) existing film holding device a second identical film holding device is arranged.