JPH0542434Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spool for winding and storing film in a 16 mm or 35 mm photographic film cartridge, and more specifically relates to injection molding of the spool.

[Conventional technology]

The Patrone for 16mm or 35mm film consists of a cartridge outer cylinder that forms a cylindrical capsule portion with a film drawer beak-like slit on the cylindrical circumferential surface;
It is composed of a spool which has flanges on both sides of the film winding shaft and is housed in the cartridge outer cylinder, and a cap which is attached to both ends of the cartridge outer cylinder and pivotally supports the outer end shaft of the flange of the spool.

A 16 mm or 35 mm film (hereinafter simply referred to as film) is cut to a certain length, and the end portion thereof is locked to the winding shaft of a spool using adhesive paper or a locking mechanism. The film is wound around the shaft of the spool and is inserted and loaded into the cartridge outer cylinder, which has one end capped with the cap, and then the other cap is mounted, and the tip of the film is inserted into the beak-shaped slit. It is visible to the outside. A pair of telescopic strips of light-shielding members are attached to the inside of the cartridge outer cylinder at the portion forming the beak-shaped slit, and the film is sandwiched between them and wound or pulled out. This keeps the film inside protected from light, making it possible to load a cartridge containing film into the camera in a bright place.

[Problem that the invention attempts to solve]

When winding a film onto a spool shaft and loading it into a cartridge, a cap is attached to one end of the cartridge in advance, and a cap is attached to one end of the cartridge to support the spool. One end shaft of the spool shaft is loosely fitted into the hole, and then another cap is loosely fitted onto the other end shaft. The spool shaft support hole is formed to have a slightly larger diameter than the spool shaft so that both end shafts can easily fit loosely into the cap shaft support hole.

FIG. 3 is a plan view of the conventional cartridge as seen from the axial direction with the cap removed. In the figure, F is a film, 1 is a cartridge outer cylinder, 2 is a spool, and 21 is a flange. Due to its own elasticity, the film F housed in the cartridge outer cylinder 1 expands like a clockwork spring, and as shown by the dashed line in the same figure, the outer part of the film F is attached to the flange 21. This results in a portion that is not covered or a portion that floats above the flange surface due to miswinding.
This portion has a poor light shielding effect compared to the portion covered by the flange 21.

When the above-mentioned loose film is subjected to the rotational torque of winding and unwinding in the cartridge, or when the film becomes loose due to elasticity when the film stops rotating,
The inner surface of the flange disk and the edge of the film rub against each other while being in strong pressure contact, and pressure buildup may occur due to friction at the edge of the high-sensitivity film, which is susceptible to pressure buildup.

Furthermore, if the part that floats up from the flange disk due to slack winding is dragged inward while rubbing against the periphery of the flange disk due to the rotational torque, or if the beak-shaped slit portion is misaligned in the spool axis direction, the film may be moved to the outside of the flange disk. Pressure build-up may also occur when the material is dragged out.

FIG. 4 is a partial plan view of the film that was taken up and rewound by motor drive and subjected to an exposure test (xenon lamp; 80,000 lux, 1 minute) while loaded on the spool. The edges in the figure have a pressure fog due to friction f ₁ and a fog due to leakage light.
This is an illustration of _f2 . Light leakage fog f ₂ may cause white spots f ₃ depending on the relationship between leakage light and friction.

On the other hand, in the injection molding of the spool that is integral with the flange that is involved in the edge pressure fogging of the film, a fifth
An injection molded core as shown in the figure is conventionally used. However, for convenience of explanation, the size and length ratio of each part may differ from the actual product.

Fig. 5a shows the main components of the injection molded core, including a fixed core B, a fixed side pin P _B , and a slide core S ₁ that slides on the core B from the left and right in the drawing plane and joins in the XY plane. and S ₂ , a fitting core C that fits into the joined S ₁ S ₂ core set from above, and a pin P _C that penetrates into the core C and the S ₁ S ₂ core set, and the injection molding core is assembled, and the mold is closed. show. The gap R created by the injection molding core is the cavity of the spool R. Figure a is a cross-sectional view taken along a plane that includes the axis of Kibity R and is perpendicular to the XY plane. Fig. 5b shows the sliding state of the slide core _S2 on the fixed core B, and Fig. 5c shows the state of the parting surface at the periphery of the flange of the spool R and the sliding cores _S1 , S2 _.
Alternatively, an air vent v provided on the parting surface of the fitting core C is shown.

The molten resin is press-fitted from the gate G of the pin P _B on the fixed side into the cavity R while excluding air from the parting surface gap or especially provided air vent v, and the spool R is formed. After solidification of the resin, the cores are sequentially opened and the spool R is taken out.

In the conventional injection molding core, as shown in Fig. 5b, the slide cores S ₁ and S ₂ rub against the fixed core B and wear out, resulting in expensive molding, and the dimensional stability of the spool flange plate thickness. becomes a problem.

Furthermore, as shown in Fig. 5c, an air vent V is provided on the spool flange portion to ensure smooth casting of the molten resin, but this air vent must be provided on the parting surface due to the mold engraving of the air vent. The molten resin protrudes and causes “burrs”
If this occurs, the edges of the film may be damaged or pressure may be disturbed when the film is taken up or unwound from the spool.

[Purpose of invention]

The first object of the present invention is to provide a spool that does not damage the injection mold core when the spool is assembled into an injection mold.
The object of the present invention is to provide a spool that does not cause flaws or pressure build-up on the edges of the film.

[Means to achieve the purpose]

The object of the present invention is to form a parting line of an injection molded core in the injection molding of a spool in which a flange plate is provided with long and short end shafts at both ends of the spool shaft for winding photographic film and storing it in a cartridge. This is achieved by a photographic film spool characterized in that it is injection molded to avoid the inner surface of the flange lid and to be positioned on the peripheral thickness surface of the flange lid.

Next, the present invention will be explained with reference to FIG.

The constituent parts of the mold core for injection molding of the present invention are exactly the same as the mold core structure previously explained in FIG. 5, and therefore the names and symbols of each mold core are the same.

However, the present invention differs from conventional mold cores in that the parting surface on the periphery of the flange plate of the spool R of the cavity (R), which is formed in a closed mold, is a flange. The purpose is to provide it at a flat position that avoids the inner surface position where the film is wound around the spool of the disc.

With this configuration, when assembling the mold (closed mold, open mold), as shown in Fig. 5b, the surfaces of slide cores S ₁ and S ₂ that are most susceptible to damage, which contact the inside of the flanges, are Contact and sliding with the matching core C can be avoided, deformation and wear can be avoided, and its regularity can be maintained for a long time. Also inevitably air vent v
By being located outside the periphery of the flange, even if a burr occurs, contact with the film edge is almost eliminated, and the burr can be easily and completely removed.

In the present invention, the parting surface of the flange portion is preferably set at a position 0.2 to 0.8 mm away from the inner surface of the flange, regardless of whether the flange peripheral edge is tapered or not.

The above-mentioned injection molding mold core of the present invention does not cause wear or damage to the flange contact portion even when used for a long period of time, and does not cause an increase in the spool unit price due to expensive mold core replacement. Favorable performance can also be obtained with the spool according to the invention.

〔Example〕

Embodiments of the present invention will be described based on the accompanying drawings.

FIG. 2 is a perspective view showing the structure of a cartridge for a photographic flange that accommodates a spool according to an aspect of the present invention.

The cartridge outer cylinder 1 and the pair of caps 3a and 3b according to the present invention are all identical in shape and size to those used in conventional film cartridges.

That is, the cartridge outer cylinder 1 is a cylindrical member made of a sheet metal material such as a cold-rolled steel plate or a surface-treated steel plate, or formed from a synthetic resin material such as polystyrene, polyethylene, or ABS. A light-shielding member telemp 111t is formed into a beak-shaped slit and serves as a protection for the film surface on the inner surface.
is attached to form a beak-shaped slit 11.

The cartridge outer cylinder 1 also has a pair of ring-shaped fitting grooves 12a and 12b formed by simultaneous molding on the circumferential surface near its left and right side ends.
Caps 3a and 3b are attached to caps a and 12b.

The caps 3a and 3b are disc-shaped members made of a sheet metal material or a synthetic resin material, similar to the cartridge outer cylinder 1, and their peripheral edges are slightly narrowed toward the center so that they do not fit outside the cartridge. When attached to the tube 1, it is press-fitted and further engaged with the fitting grooves 12a, 12b to be fixed. There is also a method in which the cap is crimped onto the outer barrel of the cartridge.

The spool 2 shown in FIG. 2 uses a four-piece injection molded core of the type shown in FIG. The spool is shown as a spool that has been released from the mold and subjected to finishing processing, and a spool in which the end of the film core is secured with adhesive paper is shown as an example.

[Effect of idea]

The problem of residual burrs when releasing the flange core from the mold is reduced, and an effective and stable injection molding spool can be supplied at a low cost.

[Brief explanation of drawings]

FIGS. 1 and 5 are cross-sectional views of the injection molding core of the present invention and the conventional type, respectively, when parting is performed. FIG. 2 is an exploded perspective view of a cartridge using the spool of the present invention. Figure 3 is a plan view of the cartridge containing the spool wound with film, viewed from the spool axis direction with the cap removed.
The figure is an explanatory diagram of edge pressure fog and light leakage fog. B... Fixed core, S ₁ and S ₂ ... Slide core,
C...Mating core, P _B ...fixed side pin, P _C ...mating side pin, R...spool assembly mold, G...gauge, v...air vent.

Claims (1)

[Scope of utility model registration request] In injection molding of a spool in which a flange board is provided with long and short end shafts left at both ends of the shaft of the spool for winding photographic film and storing it in a cartridge, the parting line of the injection molding core is placed so as to avoid the inner surface of the flange board. A spool for photographic film, characterized in that the spool is injection molded by positioning the spool on its peripheral thickness surface.