JP4354833B2 - Clip section of film stretching machine - Google Patents

Description

  The present invention relates to a structure of a clip portion that grips a film-like body in a uniaxial film stretching machine that travels a film-like body such as a sheet or a film and stretches in the width direction or a biaxial film stretching machine that also stretches in a traveling direction. .

In the production of a film-like body, stretching is usually performed to form a film having an appropriate thickness or to increase the strength of the film. About the extending | stretching, there exists the method of extending | stretching in the conveyance direction with a roll with a roll, and the method of extending | stretching in the direction orthogonal to a conveyance direction with a tenter.
Further, there is a method called a simultaneous biaxial tenter in which a special tenter is used to simultaneously stretch in the conveyance direction and the orthogonal direction. The simultaneous biaxial tenter is used at the time of manufacturing a thermoplastic resin film such as polyolefin or PET. In such a simultaneous biaxial stretching tenter, a clip portion is used that grips the film at both ends thereof and controls conveyance and stretching.

  In particular, when a slippery film is stretched, a phenomenon called slipping off, in which the gripped film-like body slips off from the clip part, tends to occur. As a method for preventing this, a method in which a grip portion of a film-like body is processed in advance has been known, and is disclosed in Patent Document 1, for example. According to this document, a configuration is disclosed in which discontinuous raised portions are formed by perforation at both ends of a sheet or film, and the tip of a clip lever is hooked on the raised portions.

Further, as a configuration in which the shape of the clip portion is changed, there are technologies disclosed in Patent Document 2 and Patent Document 3.
According to Patent Document 2, it is a simultaneous biaxial stretching method, and the length of the moving direction of the film in the gripping part is different between the upper part and the lower part, and the gripping part having a longer clip length is arranged in the lower part. Is disclosed. This disclosure is a technique for preventing film breakage during stretching, and is therefore configured not to cause stretching stress concentration. However, such a technique cannot firmly grip a slippery film and cannot achieve the object of the present application.

Patent Document 3 is a technology in which a film holding portion is configured so that the film holding surface of the clip is inclined with respect to the film surface, and the main purpose is to eliminate the thermal dead space at the time of stretching. It is disclosed that the strength will be strengthened.
However, even though such a conventional configuration contributes to increasing the gripping force in the width direction to some extent, the gripping force in the traveling direction hardly increases, and slipping may occur particularly during biaxial stretching.

JP-A-49-59174 JP 62-278018 A Japanese Utility Model Publication No. 43-23750

  The present invention was created in view of the above-described problems of the prior art, and the object thereof is to provide a clip part of a film stretching machine that is less likely to come off even for various film-like bodies. In particular, it is to provide a clip portion that can cope with film-like bodies having different original film thicknesses without replacing parts.

In order to achieve the above object, the clip portion of the film stretching machine according to the present invention has the following characteristics.
That is, the invention according to claim 1 is a clip portion of a film stretching machine used for gripping when gripping both ends of a traveling film-like body and stretching at least in the width direction, and is substantially downward in a side view. a clip wings and a clip base which forms an arc plate shape is placed facing to grip and release the film like body between the clip base and clip wings and rotated toward the clip wings clip base a configuration, the clip base is characterized in that the dam portion at least one of the film-like member traveling direction front side or rear side of the contact position between the clip wings are formed.

  The invention according to claim 2 is characterized in that the clip pedestal has a tapered shape with a front height and a rear height when viewed from the film-like body, and the clip blades are disposed so as to be able to contact the tapered slope portion. To do.

The invention according to claim 3 is characterized in that the clip blade has a substantially arcuate disk shape having a circumferential surface substantially parallel to the film-like body width direction. The invention according to claim 4 is characterized in that the thickness of the clip blade is 2 mm to 8 mm.
Furthermore, invention of Claim 5 provides the structure which provides a serration groove in a contact part with a film-form body in at least any one of a clip base or a clip blade | wing.

The following effects are achieved by the above means. That is, according to the first aspect of the invention, it is very difficult for the clip to come off, and this is particularly effective for stretching a slippery film. At the same time, since a high gripping force can be obtained, it is suitable for use in stretching a film-like body that requires high tension.
Furthermore, since it is possible to prevent slipping in both the traveling direction and the width direction of the film-like body, this structure contributes to stretching of the film-like body in which complicated tension is generated in the biaxial direction of the film.

According to the second aspect of the present invention, in addition to the above, the film-like body can be securely gripped without replacing parts or the like when stretching an original film having various thicknesses.
According to the invention which concerns on Claim 3, since an area which contacts a film-like body is small and a pressure concentrates, a film-like body can be hold | gripped firmly. It also contributes to dealing with various thicknesses of the film. Furthermore, as in the invention according to claim 4, according to the configuration in which the thickness is reduced as compared with the prior art, the stress is concentrated and a particularly strong grip can be obtained.
The invention according to claim 5 is a configuration in which the gripping force of the film-like body is further increased by the serration groove.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best mode for carrying out the invention will be described based on examples shown in the drawings. The embodiment is not limited to the following.
FIG. 1 shows a plan view of a simultaneous biaxial tenter (hereinafter referred to as a tenter) as an example of a film stretching machine according to the present invention. The tenter is a tenter that stretches a raw film having a thickness of 100 μm to 2000 μm in the traveling direction and the width direction, for example, about 3 to 10 times when a polyolefin-based film is produced. In the practice of the present invention, the material of the film is arbitrary, but in particular when it contains a large amount of plasticizer, it oozes out and the film surface becomes very slippery. A technique for solving this is the present invention.

The unstretched film (1) enters the tenter from the direction of the arrow in the figure, and is conveyed while being gripped at both ends by the conveying mechanisms (2) and (3) arranged on the left and right of the tenter. FIG. 2 shows a front view for explaining the clip portion (10) of the transport mechanisms (2) and (3).
As shown in the figure, a clip portion (10) is attached over the entire circumference of the transport mechanism (2) (3), and travels while the end of the film (1) is gripped. ) As the distance between (3) becomes longer, it is stretched in the width direction. Further, the distance between the clip portions (10) becomes longer, so that it is simultaneously stretched in the traveling direction.

  The transport mechanism (2) (3) can employ, for example, a pantograph structure as disclosed in Patent Document 4 by the applicant of the present application, and is connected by pantographs (11), (12), and (14). The clip portion (10) is attached to the crosspiece (13). Furthermore, a rotatable wheel (15) is attached to the lower end of the crosspiece (13), and the transport mechanism (2) (3) is transported by the wheel (15) traveling on a rail (not shown). I do.

JP 2003-236927 A

  A chuck variator (16) is disposed in the middle of the transport path, and in the present embodiment, it is configured, for example, as a disk or a substantially triangular pyramid. When the chuck (20) of the clip portion (10) comes into contact with the chuck variator (16) along with the conveyance, the chuck (20) is displaced, and the film is released.

Details of the clip portion (10) according to the present invention will be described with reference to FIG. 3 showing a side view and FIG. 4 showing a front view. In FIG. 3, the solid line indicates a state where the film is gripped, and the alternate long and short dash line indicates a state where the grip is released. In order from the top, the chuck (20) guided to the chuck variator (16) and rotatable about the rotation axis (21), and the direction of the chuck (20) about 40 degrees with the rotation axis (21) as a boundary. A gripping support portion (22) that is refracted and continuously provided is formed.
Accordingly, as the chuck (20) changes from the inverted state (solid line) at the time of gripping to the standing body (one-dot chain line) at the time of release, the gripping support part (22) is in the upright state (solid line) and retracted ( Switch to the alternate long and short dash line).

  One end of the spring (23) is attached to a part of the grip support part (22), and the other end is attached to the base body (30) of the clip part (10). The grip support (22) is surely moved to a predetermined retracted state by the biasing of the spring when it comes into contact with the chuck (20) from the right side and is brought into the standing state.

A clip blade (24) according to the present invention is disposed at the lower end of the grip support (22). The clip blade (24) forms a circular arc portion (24a) downward in a side view, and is thinner than the grip support portion (22), as is apparent from FIG.
In this embodiment, the thickness of the clip blade (24) is about 4 mm, and according to the verification by the applicants of the present application, it has been found that particularly suitable grip can be realized when the thickness is 2 mm to 8 mm, especially 3 mm to 6 mm.

Further, a clip pedestal (40) is fixed by a bolt (41) to the lower portion of the substantially U-shaped base body (30) in side view. The clip pedestal (40) has a front height and a low height when viewed from the film side, and is provided with an inclination of about 16 degrees. The inclination angle is preferably about 10 to 45 degrees, and in particular, 10 to 30 degrees is optimal in order to avoid sharp bending of the film edge.
In the implementation of the present invention, the effect can be obtained even if the inclination angle is very small, and can be set to 5 degrees or less, for example.

  During gripping, the chuck variator (16) presses the chuck (20) from the left to the right in FIG. 3, so that the arc portion (24a) moves toward the tapered portion (42). The film is gripped between the part (42) and the arc part (24a).

  When tension in the width direction (leftward force in FIG. 3) is generated on the film in such a gripping state, the arc portion (24a) rotates to the left due to friction according to this configuration, so that the film is deeper. Since the arc portion (24a) acts to bite in, the gripping force increases. Therefore, it is possible to easily perform strong gripping without the film being detached.

  In the present invention, the combination of the arc portion (24a) and the taper portion (42) allows the arc portion and the taper portion to be gripped in a wide range of places even when films with various film thicknesses are interposed. There is no need to replace the clip portion (10) according to the thickness. That is, in the configuration in which the clip pedestal (40) is horizontal, the conventional film thickness can only correspond to the original film thickness up to 1500 μm, but in the configuration in which the tapered portion (42) according to the present invention is provided, 5000 μm or Further thicknesses can be accommodated.

  In addition, it is not essential to provide a Taber part in the structure of this invention. Even when the clip base (40 ′) is horizontal, for example, the arc portion (24a ′) is shaped as shown in a front view in FIG. 5A and a side view in FIG. If the distance from the clip pedestal is reduced as the gripping state is changed from the released state, it is possible to effectively grip the tension in the width direction of the film.

As a feature of the present invention, the clip pedestal (40) is formed with dam portions (43) and (44) on both sides in front of the portion where the clip blade (24) abuts, and the dam portions (43) and (44). The arc portion (24a) comes into contact with the concave portion (45) surrounded by ().
The dam portions (43) and (44) have a height of 0.8 mm and the width of the recess (45) is 12 mm. These numerical values correlate with the width of the clip blade (24), and it is necessary that the width of the concave portion is wider than the width of the clip blade.
FIG. 6 shows an example of a front view 2 for explaining the action of the weir portion.

  The main purpose of the present technology is to increase the gripping force in the traveling direction of the film. Unlike the conventional configuration, the film to be gripped has a waveform in the traveling direction at the gripping portion, and therefore does not slide back and forth. In particular, in the present invention, by pressing the clip blade (24) with a shorter thickness (length in the traveling direction), upward pressing by the weir portions (43) and (44) and downward pressing by the arc portion (24a) are performed. Together, it has a very strong gripping effect.

The shape of the weir portions (43) and (44) may be formed by providing a convex portion on the clip pedestal (40) as shown in FIG. 6 (a), or the shape of the clip pedestal (as shown in FIG. 6 (b)). 40), a groove (45) may be formed by digging a groove, and dam portions (43) (44) may be formed on both sides.
In addition, although it is desirable to provide a weir part in the front and back both sides of the advancing direction, when only one is provided, since the film slip of the advancing direction can be suppressed, it is possible as embodiment of this invention.

As the shape of the dam part and the concave part, the height of the dam part (depth of the concave part) is preferably about 0.5 mm to 2 mm, and if it is smaller than this range, the effect of the dam part becomes small and large. In some cases, the amount of deformation of the film increases, making it difficult to perform suitable stretching and release. But it can set suitably with the material of a film, the thickness of a raw film, and the thickness of a product.
Further, the interval between the weir portions (the width of the concave portion) is preferably 6 mm to 16 mm. In particular, in relation to the thickness of the clip blade, the distance between the dam portion and the side surface of the clip blade, the thickness of the clip blade is approximately 1: It is preferable that the configuration is 1: 1.

In addition, it is desirable to implement this structure which provides a dam part (43) (44) with the structure which provides a taper part (42), and in a present Example, it is uniform from the high part of a taper part (42) to a low part. It is arranged with a high height and width.
As another example, it is effective to increase the height of the weir portion or to widen the width when the original film of the film is thick, so in FIG. 3 according to the gripping position when the thickness is thick. You may make it increase the height (depth of a groove | channel) and a space | interval of a dam part, so that it progresses to the right side.

As a configuration for further increasing the gripping force, in the present invention, a serration groove can be provided in a contact portion of the clip base (40) or the clip blade (24) with the film.
FIG. 7 is a plan view showing the serration groove of the clip pedestal (40) used in this embodiment, and 45 degrees on the entire surface of the recess (45) between the weir portions (43) and (44) in the taper portion (42). A serration groove (46) is formed by twill groove processing.
Similarly, in FIG. 8, serration grooves (25) are provided on the substantially entire arc portion (24a) of the clip blade (24).

The serration grooves (46) and (25) are engaged with the film at the time of gripping the film to firmly suppress the slipping of the film, and this configuration makes it possible to completely prevent the film from coming off.
The shape of the serration groove may be a sawtooth shape, a knurled shape, or the like, in addition to a 45 degree cross shape. In particular, the arc portion of the clip blade may be configured to be strongly bitten into the film as an acute edge.
In addition, you may provide a serration groove only in any one of a clip base or a clip blade | wing. The serration groove does not need to be the entire surface, and may be configured to be provided in a part, for example, in the vicinity of the contact position with the clip blade.

The present invention provides a clip portion that can firmly hold a raw film having various thicknesses by the above-described configuration.
The thickness of the original film applicable to the clip part is preferably 50 μm to 5000 μm, more preferably 100 μm to 2000 μm.

Test example 1

In order to verify the effect of the present invention, a conventional product having a clip blade width of 20 mm and a clip pedestal having a flat shape, a related product 1 in which only the width of the clip blade is 4 mm, and a clip pedestal are shown. In the present invention product 2 in which the weir portion as in the above embodiment was arranged, and in the present invention product 2, the present invention product 3 in which the clip base was provided with the tapered portion as in the above embodiment was compared.
The film was gripped by each clip part, and the tension at which slip in the traveling direction occurred was measured. The results are shown in Table 1 below.

As described above, it was confirmed that the gripping force was improved particularly in the traveling direction by the formation of the weir portion according to the present invention. Further, as can be seen from the results of the conventional product and the product 1 of the present invention, it can also be confirmed that the gripping force can be improved by setting the thickness of the clip blade as in this embodiment.
Further, the effect of the tapered portion is also remarkable, and it can be seen that the combination of these can enhance the gripping force by 3 to 4 times compared to the conventional product.

In addition, when extending | stretching a film-form body with a extending | stretching machine, it is unavoidable that it becomes a loss about the edge part of a holding | grip as also described in the prior art. In this respect, the clip portion remains bitten in the same manner as in the prior art according to the present invention, but there is no influence on the part used as a product.
However, according to the present application, since the clip is surely gripped and the clip does not come off, the product loss as a whole can be greatly suppressed, which contributes to improvement in productivity, resource saving, and reduction in product price.

1 is an overall view of a film stretching machine according to the present invention. It is a front view explaining the clip part of a conveyance mechanism. It is a side view of the clip part by this invention. It is a front view of the clip part by this invention. It is explanatory drawing explaining the shape of the circular arc board of a clip part. It is explanatory drawing explaining the structure of a weir part. It is an example of installation of a serration groove of a clip base concerning the present invention. It is an example of installation of the serration groove of the clip blade according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Clip part 20 Chuck 21 Rotating shaft 22 Grasp support part 23 Spring 24 Clip blade 24a Arc part 30 Base 40 Clip base 41 Fixing bolt 42 Taper part

Claims (5)

When gripping both ends of the traveling film-like body and stretching at least in the width direction, it is a clip part of a film stretching machine used for gripping,
Side view, and a clip wings and a clip base having a substantially circular arc plate shape is disposed facing downward, the film-like between the pivots towards the clip wings clip seat the clip base and clip wings It is a configuration for gripping and releasing the body,
The clip part of a film stretching machine, wherein the clip base is formed with a weir part on at least one of a front side and a rear side in a film-like body traveling direction at a contact position with the clip blade. The clip of the film stretching machine according to claim 1, wherein the clip pedestal has a tapered shape with a front side being high and a back side being low when viewed from the film-like body, and the clip blades are disposed so as to be able to contact the inclined surface of the taper shape. Department.   The clip part of the film stretching machine according to claim 1 or 2, wherein the clip blade has a substantially arcuate disk shape having a circumferential surface substantially parallel to the film-like body width direction.   The clip part of the film stretching machine according to claim 1, wherein the clip blade has a thickness of 2 mm to 8 mm.   The clip part of the film extending machine of Claim 1 thru | or 4 which provided the serration groove in the contact part with a film-like body in at least any one of the said clip base or the said clip blade | wing.

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