JP4644090B2 - Film stretcher - Google Patents

Description

  The present invention relates to a film stretching apparatus.

  For example, as described in Patent Document 1, two endless chains are arranged on both sides of a film, and both endless chains are gripped and conveyed by clips provided at equal intervals on the endless chain. A film stretching apparatus (tenter) that stretches a film in the lateral direction by increasing the distance between chains is known.

  In general, when a belt-like film is stretched in the longitudinal direction, the width of the film becomes thin. Similarly, when a film is stretched in the transverse direction by a conventional film stretching apparatus, an internal stress that tends to shrink in the longitudinal direction is generated. Such a longitudinal internal stress has an effect on the molecular arrangement of the film and sometimes gives undesirable characteristics.

  In addition, in Patent Document 2, a film that does not cause internal stress in the vertical direction by contracting the film in the vertical direction when stretching in the horizontal direction by loosening and gripping the film between the clips. A method is described, and a method is disclosed in which a film is made slack by feeding the film at a speed higher than the speed of a clip.

However, in the method disclosed in Patent Document 2, in particular, when the gap between the clips is reduced for uniform stretching, the amount of slackness of the film varies due to a shift in the timing at which the film is gripped by the clip, etc. There was a problem that the state was likely to be uneven.
JP-A-5-319648 JP-A-5-241021

  Then, in view of the said problem, the subject of this invention makes it a subject to provide the film extending | stretching apparatus which can extend | stretch a film to a horizontal direction, without generating an internal stress in the vertical direction.

In order to solve the above problems, a film stretching apparatus according to the present invention grips and conveys both side edges of a film, and synchronizes the clips with a plurality of clips that stretch the film in a direction perpendicular to the transport direction. A slack member that moves in a direction perpendicular to the film between the clips arranged in the film transport direction at the side edge of the film while moving in the film transport direction , The clip is disposed on both side edges of the film, and before the film is gripped, the clip protrudes beyond the surface for gripping the film, and the clip grips the film after gripping the film It shall be set back from the surface .

  According to this configuration, the film on the upstream side can be pulled in a certain amount so that the film is slack between the clips by the slack member pressing the film between the clips. This slackness absorbs shrinkage in the longitudinal direction when the film is stretched in the transverse direction, so that no internal stress in the longitudinal direction is generated in the film. Further, since the amount of slackness of the film is determined by the positional relationship between the clip and the slackening member, there is little variation and the film can be stretched uniformly.

Further, in the film stretching apparatus of the present invention, the relaxing members are respectively arranged on the outer circumferences of rotating bodies that rotate around an axis perpendicular to the transport direction of the clip at a position away from the clip in a direction perpendicular to the film. You may arrange so that it may protrude.

  According to this configuration, the relaxing member can be moved up and down between the clips with a simple mechanism, and the film can be slackened.

  Moreover, the film stretching apparatus of this invention WHEREIN: The said relaxation member may have a relaxation rod part parallel to the surface of the said film and orthogonal to a conveyance direction.

  According to this configuration, by extending the relaxing member between the clips from the inside of the clip, interference between the mechanism that drives the relaxing member and the clip can be avoided.

  As described above, since the film stretching apparatus of the present invention grips the film with the clip while the film is loosened by the relaxing member, it absorbs the shrinkage in the vertical direction associated with the stretching in the horizontal direction to the film in the vertical direction. Does not cause internal stress.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 is a plan view of a film stretching apparatus 1 according to an embodiment of the present invention. In the film stretching apparatus 1, the film 2 is fed between the two endless chains 6 from the raw fabric reel 3 through the tension roller 4 and the guide roller 5. The endless chain 6 is provided with a number of clips 7 at regular intervals, grips both ends of the film 2 and conveys it in the direction of the arrow, and stretches the film 2 in the lateral direction to widen it. Above the endless chain 6, there are provided two disk-like rotating bodies 9 that rotate around an axis 8 that is perpendicular to the traveling direction of the endless chain 6 and that are positioned inside the clips 7 that grip both ends of the film 2. A loosening member 10 that protrudes between the clips 7 is provided on the outer peripheral portion of each rotating body 9. The film 2 held and conveyed by the clip 7 and widened is taken up by the take-up reel 13 through the guide roller 11 and the tension roller 12.

  In FIG. 2, the rotary body 9 seen from the film 2 center is shown. The rotating body 9 rotates in synchronization so that the peripheral speed of the relaxing member 10 matches the speed of the endless chain 6 that transports the film 2, that is, the clip 7. The relaxation member 10 is located at the center of the two clips 7 when in the lowest position.

  FIG. 3 shows a vertical cross section passing through the axis of the shaft 8, and the relationship between the clip 7 and the relaxing member 10 at the lowest point will be described. The clip 7 is fixedly supported by a fixed piece portion 7a on which the film 2 is placed, a support arm portion 7b extending above the fixed piece portion 7a, and a gripping shaft 7c at the tip of the support arm portion 7b. The gripping piece 7d has a gripping piece 7d that can be brought into contact with the upper surface of the piece part 7. The gripping piece 7d guides the lever part 7e projecting upward, thereby gripping the film 2 between the fixed piece part 7a ( It is rotated so as to open the film 2 (illustrated by a two-dot chain line) apart from the fixed piece portion 7a.

  The loosening member 10 is formed by bending a round bar at a right angle, and is supported in a radial direction from the outer periphery of the disk-shaped rotating body 9 and the shaft 8, in other words, parallel to the surface of the film 2 and endless. It consists of a relaxation rod portion 10b perpendicular to the conveying direction by the chain 6. At the lowest point, the lower end of the relaxing member 10, that is, the lower surface of the relaxing rod portion 10 b is lowered below the upper surface of the fixed piece portion 7 a of the clip 7, that is, the surface on which the film 2 is gripped.

  FIG. 4 shows in detail the vertical movement between the clips 7 of the slack bar portion 10 b of the gripping member 10 due to the rotation of the rotating body 9. The clip 7 is advanced in the direction of the arrow by the endless chain 6. The fixing piece 7a on the right side of the figure is located below the side edge of the film 2 and the clip 7 in the state where the gripping piece 7d opens the film 2 is rotated by the rotation of the rotating body 9 so that the relaxing member 10 is rotated. The relaxation rod portion 10b is lowered. The relaxing rod portion 10b abuts on the film 2 and further descends to push down the film 2. However, since the front and back are supported by the fixed piece portion 7a, the film 2 is placed between the two clips 7 on the lower side. To relax. Since the downstream clip 7 grips the film 2, the loose film 2 is pulled out from the upstream original fabric reel 3 and is overfeeded (oversupplied) to the endless chain 6. .

  When the relaxing member 10 reaches the lowest position, the clip 7 closest to the upstream side closes the gripping piece 7d and grips the side end of the film 2. Thereafter, the loosening member 10 rises and separates from between the clips 7, but the clip 7 conveys the film 2 while holding it in a loose state.

  Thereafter, the endless chains 6 on both sides of the film 2 widen each other, stretch the film 2 in the lateral direction, and widen it. At this time, the film 2 contracts in the vertical direction, but the slack between the clips 7 compensates for the contraction, and the film 2 does not generate internal stress in the vertical direction. Thereby, the film 2 can be ideally uniaxially stretched in the transverse direction.

  As described above, the film stretching apparatus 1 according to the present embodiment has a structure in which the relaxing member 10 including the supporting portion 10a and the relaxing rod portion 10b is fixed to the disk-shaped rotating body 9 that is easy to process and has high accuracy. 7, it is possible to extend only the relaxing rod portion 10 b of the relaxing member 10 to an accurate position between the clips 7 while preventing the interference between the rotating body 9 and the clip 7. Moreover, since the relaxing member 10 is a round bar, the film 2 can be loosened without being damaged.

  Further, in the film stretching apparatus 1, if the height of the shaft 8 is finely adjusted, the amount of slack (overfeed amount) of the film 2 can be adjusted, and the length of the film 2 that is not gripped by the clip 7 is minimized. The film 2 can be reliably stretched.

  In the above embodiment, the relaxing member 10 is provided on the outer periphery of the rotating body 9, but it may be moved up and down between the clips 7 while moving in the film 2 conveying direction in synchronization with the clip 7. It may be driven by any mechanism such as an endless chain that circulates upward or a plurality of linear motion devices that sequentially move in the transport direction of the film 2.

The schematic plan view of the film extending apparatus of this invention. Sectional drawing in the film center of the rotating body vicinity of the film stretching apparatus of FIG. Sectional drawing seen from the film conveyance direction of the clip and loosening member of FIG. The side view which looked at the clip of FIG. 1 from the film center.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film stretching apparatus 2 Film 6 Endless chain 7 Clip 8 Shaft 9 Rotating body 10 Relaxing member 10b Relaxing rod part

Claims (3)

A plurality of clips for gripping and transporting both side edges of the film and extending the film in a direction perpendicular to the transport direction;
A slack member that moves in the direction perpendicular to the film between the clips arranged in the film conveyance direction at the side edge of the film while moving in the film conveyance direction in synchronization with the clip. ,
The loosening member is arranged such that the clip is disposed on both side edges of the film and protrudes beyond the surface where the clip grips the film before the film is gripped, and after the clip grips the film A film stretching apparatus, wherein the film is retracted from a surface for gripping the film. The relaxing members are arranged so as to protrude from the outer periphery of a rotating body that rotates around an axis perpendicular to the transport direction of the clip at a position away from the clip in a direction perpendicular to the film. The film stretching apparatus according to claim 1, wherein the film stretching apparatus is characterized in that:   3. The film stretching apparatus according to claim 1, wherein the relaxing member includes a relaxing rod portion that is parallel to the surface of the film and perpendicular to the conveying direction.

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