JPS6128200Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spool for photographic film that facilitates positioning of the spool when attaching or locking the end of the film to a winding shaft.

Various types of photographic film are currently used, but the so-called 35mm film (135 with cartridge) used in 35mm cameras or half-size cameras has a spool that can be rotated inside a cylindrical cartridge. The end of the film is secured to this spool. Conventional methods for securing the end of the film to the spool include wrapping adhesive paper with adhesive on one side around the spool and holding the end of the film between both ends of the adhesive paper. A method is known in which a locking hole at the end of the film is engaged with a locking pawl formed on the roll shaft.
In the former method, when the film fixed on the spool is pulled in the longitudinal direction, the limit force at which the film separates from the spool due to breakage, etc., is much larger than in the latter method, but due to the adhesive The latter method is widely adopted because there are problems such as parts of the film getting dirty, the process of holding the ends of the film with adhesive paper being complicated, and the adhesive strength decreasing as the adhesive changes over time. .

By the way, the structure of the photographic film spool used in the latter method is that a film insertion opening is provided at the center of the spool's roll shaft, and a locking pawl is provided inside this insertion opening, so that the end of the film can be inserted into this opening. When the film is inserted through the film insertion opening, a locking hole formed at the end thereof engages with a locking pawl, thereby locking the film and the spool. Conventionally, the work of locking the film onto the spool has been done automatically, but this automatic locking work requires spool positioning, which always aligns the film insertion opening of the spool with the direction in which the film enters. As a positioning method, a notch or recess is provided in a part of the spool's winding shaft, or a recess is made at the same position on both sides of the winding shaft, and a positioning lever is brought into contact with the spool's outer circumference from the outside, and the spool is rotated. There is a method of stopping the rotation of the spool by dropping the lever into a notch or recess, and a method of attaching a mark near the end of the spool winding shaft to indicate the direction of the film insertion slot, and detecting this mark to detect the direction of the film insertion slot. Several methods have been proposed to determine the direction of the object.

However, with the former method, it is necessary to keep the positioning lever in constant contact with the outer circumference of the spool.
There is a problem in that it causes rotational load on the spool and is not suitable for high speeds. Even with the latter method, there are restrictions on the size and shape of the mark due to the loading of the film into the camera.

In view of the above points, the present invention makes a part of the winding shaft of the spool small in diameter, provides a projection not higher than the peripheral surface of the winding shaft on this small diameter part, and detects this projection to detect the film on the winding shaft. This allows you to know the direction of the insertion port.

The present invention will be explained below based on the drawings.

FIG. 1 is a partially cutaway view of an embodiment of a photographic film spool according to the present invention, FIG. 2 is a front view of the spool, FIG. 3 is a partially cutaway plan view of the spool, and FIG. The figure is a rear view of the spool, and FIG. 5 is a cross-sectional view taken along the line AA in FIG. 2.

As can be seen from these figures, the spool has flanges 4 and 4' near both ends of the winding shaft 3 around which the film is wound.
A film insertion opening 5 is provided in the portion sandwiched by 4'. The film insertion opening 5 passes through the winding shaft 3 at right angles to the axial direction, and of the upper and lower walls 6 and 7 forming the insertion opening 5, the upper wall 6 has a film insertion opening 5 located approximately in the longitudinal center of the insertion opening 5. A presser rib 8 is formed,
Two locking claws 9 and 10 are formed on the lower wall 7. On the other hand, ribs 6a and 7 extending in the length direction are provided approximately in the center of the outer sides of the upper wall 6 and the lower wall 7, respectively.
A is provided.

The portions of the winding shaft 3 adjacent to the flanges 4, 4' are cylindrical portions 11, 12, and a cylindrical portion 13 having a slightly smaller diameter than the cylindrical portion 11 is formed continuously to the cylindrical portion 11. A positioning protrusion 14 is formed in this small diameter cylindrical portion 13 . It is important that the height of the protrusion 14 is not higher than the circumferential surface of the adjacent cylindrical part 11.

The locking claws 9 and 10 have the same shape, and as can be seen from FIG. 5, the locking claw 9 has a horizontally extending claw portion 9a.
and an inclined part 9b which is gently inclined so as to gradually approach the upper wall 6 from the film insertion side, and the tip of the claw part 9a is inclined. By slanting the tip in this manner, the film can be easily locked in the locking claw 9. Further, the lower surface F of the claw portion 9a is parallel to the upper surface E in the horizontal direction. The distance h from the lower wall 7 to the lower surface F of the claw portion 9 is preferably 0.2 mm or more, which is slightly thicker than the thickness of the film (approximately 0.15 mm), considering the life of the mold, etc.; It has been experimentally confirmed that the locking force decreases.

The film holding rib 8 formed on the upper wall 6 has a fifth
As can be seen from the figure, it has a horizontal portion 8a and an inclined portion 8b that is gently sloped so as to gradually approach the lower wall 7 from the film insertion side, and this presser rib 8 is used to hold the film after it is locked. To prevent the film from coming off the claw, the inclined surface 8b cooperates with the inclined portion of the locking claw when the film is inserted to gradually curve the center portion of the film and apply a downward force to the film locking portion 1a. Therefore, if the height of the presser rib 8 is too low, the detachment prevention function will deteriorate, and if it is too high, the insertion resistance when inserting the film will increase.

The procedure for locking a film onto a spool having such a structure is the same as the procedure for locking a film onto a claw locking type spool of this type which has already been put into practical use, so a description thereof will be omitted.

Next, the positioning of the spool when locking the film to the spool will be explained with reference to FIG. 6.

FIG. 6 shows an example of a spool positioning mechanism, in which chucks 20 and 21 support the spool, the chuck 20 is in a fixed position, and a cylinder 20a that moves back and forth in the direction of the arrow is provided at its tip. The tip of the spool 20a is inserted into one end of the winding shaft of the spool to support one end of the spool. It can be assumed that the chuck 21 is integrated with the chuck support 22, and is moved to the illustrated positioning station by gripping the other end of the spool shaft at a spool supply station (not shown), and at this position, the chuck 21 is moved to the illustrated positioning station. Spool rotation drive unit 2
Combine with 3. 24 is a positioning pawl, and 25 is a drive unit that reciprocates the positioning pawl 24 in the direction of the arrow.

When the spool with one end of the winding shaft gripped by the chuck 21 is positioned at the axis line position with respect to the chuck 20 as shown in the figure, the cylinder 20a of the chuck 20 moves forward and its tip touches the other end of the winding shaft of the spool. The spool is thus supported at both ends. At the same time, the drive unit 25 operates to rotate the positioning pawl 24 clockwise until its tip reaches a position close to the small diameter cylindrical portion 13 of the spool and comes to rest. Thereafter, the spool rotation drive unit 23 is operated and the spool begins to rotate in the direction of the arrow while being held by the chuck 21. During one rotation of the spool, the protrusion 14 formed on the small diameter cylindrical portion 13 hits the tip of the positioning pawl 24, and the rotation of the spool is stopped. At this time, the spool rotation drive unit 2
The rotational drive of the chuck 21 is interrupted by a clutch mechanism provided inside the chuck 21. The position of the spool when the rotation of the spool stops is always the same, and the film insertion opening 5 is always in the same direction. Thereafter, when a certain period of time has elapsed since the spool started rotating, the operation of the spool rotation drive unit 23 stops, and then the cylinder 20a of the chuck 20 moves backward and the drive unit 25 moves the positioning pawl 24 counterclockwise. Rotated. The spool with the film insertion opening oriented in a certain direction is sent to the next film locking station while its position is maintained by a member (not shown), where the end of the film is inserted into the film insertion opening and locked.

In this way, the spool can be easily positioned by detecting the protrusion 14 formed on a part of the spool shaft with the positioning pawl 24, but since the positioning pawl 24 is not in contact with the spool winding shaft, rotational load on the spool can be easily determined. It is also possible to increase the speed of positioning without increasing the speed. In addition, since the height of the protrusion 14 is not higher than the circumferential surface of the winding shaft, the protrusion does not get in the way of winding the film around the winding shaft after the film is secured to the spool.

The present invention can be applied not only to spools using the claw locking method, but also to spools using the adhesive method in which the end of the film is attached to the winding shaft, but especially in the case of spools using the claw locking method, accurate positioning is required. So it is effective.

The location of the positioning protrusion is not limited to the above-described embodiments, and may be located anywhere on the winding shaft, but it is necessary that it not cause any hindrance to the winding of the film and meet various manufacturing standards.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a spool for photographic film according to the present invention, Fig. 2 is a front view of the spool, Fig. 3 is a plan view of the spool with the upper rib and top wall removed, and Fig. 4. 5 is a rear view of the spool, FIG. 5 is a sectional view taken along line A-A in FIG. 2, and FIG. 6 is a schematic diagram illustrating the spool positioning operation according to the present invention. 3... Winding shaft, 4, 4'... Flange, 5... Film insertion slot, 6... Upper wall, 7... Lower wall, 8...
Film holding rib, 9, 10...Latching claw, 12,
13... Cylindrical part, 14... Small diameter cylindrical part, 15...
protrusion.

Claims (1)

[Scope of utility model registration request] A photographic film spool for attaching or locking the end of the film to a winding shaft, characterized in that a small diameter portion is provided in a part of the winding shaft, and a protrusion that is not higher than the circumferential surface of the winding shaft is formed in the small diameter portion. A spool for photographic film.