JP2014024351A - Polymer web stretching device and polymer web continuous stretching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer web stretching device capable of repeatedly acting tenter clips with low wear.SOLUTION: The polymer web stretching device comprises (a) a driven conveyor holding the opposite end of the web, conveying the web in the device from an upper stream holding region to a downstream stretching region toward a machine direction and comprising tenter clips which are opened or closed under control, (b) a first tenter clip closer which closes the tenter clip at least partly and is located at the holding region in order to hold the web and, in addition, (c) a second tenter clip closer which is located at a downstream position of the first tenter clip closer in the holding region so as to close the tenter clip and make the web held.

Description

  The present invention relates to an apparatus and method for stretching a polymer web (eg, a film or extrudate), and more particularly to an apparatus comprising a driven conveyor having tenter clips that hold the opposite ends of the web and convey the web. Automatic opening and closing devices are provided at the upstream and downstream ends of the device for opening and closing the clip, the tenter clip has a clamp surface and a pivotable clamp arm, and the clamp arm has an upper end portion having a cam follower and a gripping surface The web is gripped by the gripping surface and the clamping surface. The clamp arm is actuated by a first closer having a cam that pivots a cam follower to grip the web. A second closer located downstream of the first clip contacts the cam follower that is at least partially pivoted and closes a clip that is not fully closed by the first closer.

  The present invention also relates to a method and apparatus for detecting a tenter clip having a rotation defect in a clip arm, particularly an abnormal tenter clip. Abnormal tenter clips, such as tenter clips with insufficient clip arm rotation, are detected by force monitoring means between the tenter clip and at least one tenter clip drive. When the force exceeds a reference value, the signal from the monitoring means automatically activates a counter that automatically counts the number of clips that have contacted the drive after an abnormal clip. An abnormal clip can be identified by stopping the machine and counting the number of clips from the drive. Abnormal clips can be repaired or replaced, for example, to prevent damage to the stretching apparatus.

  A tenter stretching device can be used to stretch a web (eg, extrudate or film) of polymeric material. Stretching may be uniaxial (stretching along one axis of the web) or biaxial. In the case of biaxial stretching, sequential stretching (stretching in one direction and then stretching in the other direction), simultaneous stretching (stretching in both directions simultaneously), or a combination thereof may be performed.

  For example, a conventional tenter device disclosed in U.S. Pat. No. 4,065,838 generally includes a plurality of tenter clips attached to two endless chains guided by a pair of expanding tracks for conveying the tenter clips. It comprises. The tenter clip moves from the open position to the closed position and grips the end of the web, such as a polymer extrudate or film. When the web is moved in the machine direction while being gripped by a clip along a track in which the web expands, the web is simultaneously stretched in both directions (machine direction and transverse direction).

  In conventional tenter devices, the tenter clip moves to a position for receiving the end of the web, and each clamp arm moves to a closed position to grip the web. As the tenter clip moves along the spreading track, the web is stretched. Finally, as it travels along the endless chain, each clamp arm reopens and opens the web. Such opening and closing means are well known (see, for example, US Pat. No. 4,065,838 and US Pat. No. 4,193,175).

  The conventional closing means includes, for example, a closing cam provided on the opposite side of the entrance of the tenter device. Similarly, a cam for opening the stretched web is provided on the opposite side of the machine exit end. The pair of cams at the inlet end and the outlet end are in a position to operate each cam follower on the tenter clip attached to the endless chain for transporting the tenter clip. See, for example, US Pat. No. 4,193,175.

  Thus, in a typical operation of the tenter device, the tenter clip opens and closes repeatedly as the continuous web moves through the machine. Repeated opening may cause the clip to deteriorate and break. If there is a defect that remains stuck in the open position after opening the cam follower, interference with the tenter clip and clip closer at the downstream end of the tenter device will also cause other parts of the tenter device such as clips, bearings, pantographs and drives to Damaged.

  Regarding damage to the tenter clip, US Pat. No. 2,096,283 (Patent Document 3) describes that the number of opening and closing tenter clips per cycle is reduced by half from 4 to 2. In addition, the tenter clip itself has been improved, for example, by adding flexibility to the cam follower mechanism of the tenter clip to reduce the deterioration of the clip. See, for example, EP 212985 (Patent Document 4). Another improvement of the clip closer or opener is to reduce clip wear. For example, U.S. Pat. No. 4,065,838 discloses a driven disk having a pad on its outer periphery that contacts a clip arm to actuate a tenter clip. US Pat. No. 5,781,974 (Patent Document 5) discloses a magnetic device for driving a tenter clip.

  JP-A-2001-162681 (Patent Document 6) and JP-A-2002-18691 (Patent Document 7) utilize the outer periphery of a freely rotating disc as a clip opener for preventing local wear of the clip arm. ing. In addition, for example, a clip driving device disclosed in Japanese Patent Application Laid-Open No. 59-48123 (Patent Document 8) includes a free rotating disk that contacts a closing arm of the clip and closes the clip. The disc is held in position by the bracket and spring, pivoted away from the damaged clip arm, and then returned to its original position by the action of the spring.

  Although the design of tenter stretching has been gradually improved, there is a need to improve the tenter clip opening and closing device so that it can withstand or prevent damage from defective tenter clips. In particular, there is a need for an improved tenter clip closer that can more fully close the clip with little wear.

  As a method for detecting an abnormal clip, Japanese Patent Application Laid-Open No. 2006-130770 (Patent Document 9) discloses a method for analyzing a trace of a tenter clip that grips an end portion of a film using a grip trace detector. If an abnormal trace is found, the machine is stopped and the abnormal clip is repaired or replaced. Japanese Laid-Open Patent Publication No. 6-24615 (Patent Document 10) discloses that the outline of a clip is compared with the outline or reference outline of an adjacent clip at a point along the tenter device. If the clip outline differs from the adjacent clip outline or reference outline, the tenter device is stopped and the abnormal clip is repaired or replaced.

  Although the method of JP-A-2006-130770 has been improved, it is difficult to implement because it is necessary to continuously monitor the trace of the tenter clip on the film during the entire operation of the tenter device. The method of JP-A 6-47615 also requires continuous monitoring. Furthermore, none of the criteria is suitable for identifying clips that do not function properly when toggled by the clip opener from the closed position to the open position. A normally opened clip leaves a suitable trace at the end of the film and has a suitable contour. However, a clip that malfunctions during opening will not close properly when recirculated to the downstream end of the tenter device, damaging the tenter device. Therefore, further improvements are needed.

U.S. Patent 4,065,838 U.S. Patent 4,193,175 US Patent 2,096,283 EP 212985 US Patent 5,781,974 JP 2001-162681 A JP 2002-18691 A JP 59-48123 A Japanese Unexamined Patent Publication No. 2006-130770 Japanese Patent Laid-Open No. 6-24615

The first polymer web stretching apparatus of the present invention comprises:
(a) a driven conveyor having tenter clips that hold opposite ends of the web, convey the web in the machine direction from an upstream gripping region to a downstream stretching region in the apparatus, and are opened and closed by control;
(b) a first tenter clip closer located in a gripping region to at least partially close the tenter clip and grip the web;
(c) further comprising a second tenter clip closer located downstream of the first tenter clip closer in the gripping region to close the tenter clip.

A method for continuously stretching a polymer web according to an embodiment of the present invention includes:
(a) (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); and (ii) upstream Transporting the polymer web to a stretching device having a gripping region and a stretching region downstream of the gripping region, and comprising an opposing track for transporting a plurality of tenter clips,
(b) A cam follower of a series of opposing tenter clips in the gripping region is brought into contact with a pair of opposing first clip closers to at least partially close the tenter clip, thereby opposing the opposing ends of the web. Gripping sequentially with a pair of tenter clips, transporting the web to the stretching area,
(c) contacting a cam follower of a series of opposing tenter clip pairs with a second opposing clip closer pair located within the gripping region but downstream of the first clip closer;
(d) The web is transported along the opposite track to the stretching region, and the web is stretched in the stretching region.

  The first tenter clip closer according to the present invention can be disposed in an entrance region (also referred to as a gripping region) of a tenter that transports a web gripped by the tenter clip. The tenter clip can be continuously conveyed along a pair of loop rails provided on both sides of the web. In the first tenter clip closer, for example, a pivotable clip arm on the tenter clip rotates upon contact, and the tenter clip is in a closed or partially closed position for gripping the web. The second tenter clip closer is disposed downstream of the first tenter clip closer. The second tenter clip closer applies a closing force and more completely closes the tenter clip (especially a tenter clip that has become more difficult to close due to, for example, dirt accumulation in the pivot region).

  In one embodiment, the first tenter clip closer is a cam and the second tenter clip closer is a disc. By acting a cam or disc against a cam follower that is part of the tenter clip, the tenter clip can be moved to the closed position.

  The cam of the first tenter clip closer can be, for example, an elongated rectangular plate or a wedge. In one embodiment, the cam has a curved surface that curves slightly outward from upstream to downstream with respect to the direction of web travel. For example, the cam may be a longitudinal plate that is inclined inward and downward with respect to the direction of travel of the tenter clip, or a horizontal plate that has an outer surface that is gradually inclined outward. The cam may be made of metal. The disc of the second tenter clip closer may be made of an abrasion resistant resin.

  In one embodiment, the disc of the second tenter clip closer is attached to the tenter device such that an axis perpendicular to the disc surface is inclined at an acute angle with respect to the web surface. For example, the disc can be attached so that the side (or plane) of the disc pushes the cam follower of the tenter clip to more fully close the clip.

  The second polymer web stretching apparatus of the present invention comprises a driven conveyor having a tenter clip that holds the web in the machine direction while holding the opposite end and can be opened and closed under control, and at least one pivot A free tenter clip opener, wherein the tenter clip opener pivots the fixed cam away from the tenter clip and a fixed cam that at least partially opens the tenter clip to open the web And a pivot connected to the fixed cam.

A method for continuously stretching a polymer web according to an embodiment of the present invention includes:
(a) the polymer web; (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); (Ii) having a gripping region, a stretching region downstream of the gripping region, and an open region downstream of the stretching region, and transporting to a stretching device having a counter track that transports a plurality of tenter clips;
(b) contacting a cam follower of a series of opposing tenter clips in the gripping region with at least a pair of opposing first clip closers to at least partially close the tenter clips, thereby causing the opposing ends of the web to The web is transported to the stretching region by sequentially gripping with the opposing pair of tenter clips,
(d) transporting the web along the opposing track to the stretching area, where the web is stretched;
(e) contacting a cam follower of a series of opposing closed tenter clip pairs with at least one pair of opposing clip openers in the open region to at least partially open the tenter clip to sequentially open the gripping portion of the web; The clip opener includes: a fixed cam that at least partially opens the tenter clip to release the web; and a pivot connected to the fixed cam to pivot the fixed cam away from the tenter clip. It is characterized by comprising.

The third polymer web stretching apparatus of the present invention comprises:
(a) a driven conveyor having a tenter clip that can be opened and closed under control while conveying the web to the stretching region in the machine direction while holding the opposite end;
(b) at least one tenter clip drive (at least partially opening and closing the tenter clip to grip or open the web), moving away from the tenter clip towards a stopper that prevents further movement by contact. )When,
(c) A counter that is automatically operated by the stopper and counts the number of tenter clips carried to the tenter clip driving device after the operation is provided.

The method of the present invention for identifying abnormal tenter clips in a continuous stretch method of a polymer web comprises:
(a) transporting the polymer web to a stretching device, and the stretching device (i) grips and transports the opposite end of the web and controls a plurality of tenter clips (abnormal tenter clips) controlled to open and close by a toggle motion. (Ii) at least one tenter clip drive device that opens and closes the tenter clip by toggle motion to open the web (the tenter clip drive device moves away from the tenter clip and moves toward the stopper). The tenter clip contacts the stopper when the abnormal tenter clip toggles with the driving device, but does not contact the stopper when the normally functioning tenter clip contacts the driving device, and the stopper is the tenter clip driving device. And (iii) the contact strike A counter that is automatically actuated by a padper and counts the number of tenter clips carried to the tenter clip drive after actuation;
(b) contacting the abnormal clip and the tenter clip driving device to move the tenter clip driving device to the stopper, and operating the counter;
(c) Stop the tenter clip transport,
(d) The number of tenter clips between the driving device and the abnormal tenter clip is counted by the counter, and the abnormal tenter clip is specified.

  In one embodiment, the position of the defective clip is determined directly from the counter. In another embodiment, a reference clip is used and the count value of the second counter is a number unique to each tenter clip. The position of the abnormal clip can be determined by addition or subtraction (for example, automatically performed by a computer or other automatic data processing device) from the number and position of the reference clip. To automatically stop the machine when an abnormal clip is detected, the computer can be linked to a tenter clip transport control device.

  The reference clip can be automatically identified, for example, using a magnetic member (eg, a magnetic bolt) on or near the clip (eg, on a pantograph arm). The magnetic member is sensed by a sensor that can detect a change in the electromagnetic field.

  The clip drive is a clip opener, a clip closer, or both. Generally, one or more opposing clip openers and one or more opposing clip closers are used for each end of the web.

FIG. 3 is a schematic diagram illustrating a tenter device including first and second tenter clip closers and openers according to an embodiment of the present invention. FIG. 2 is a side view showing the tenter clip of the tenter of FIG. 1, wherein (a) shows an open tenter clip, (b) shows a partially opened and closed tenter clip, and (c) shows a closed tenter clip. . It is a perspective view which shows an example of the 1st and 2nd tenter clip closer of FIG. 1, Comprising: The follower attachment member fixed to the 1st and 2nd tenter clip closer (it is abnormal in the 1st or 2nd tenter clip closer) The first and second tenter clip closers pivot away from the tenter clip when a strong force is applied, for example, when a broken tenter clip or defective tenter clip acts on the closer or both) It is. FIG. 4 is a plan view showing a tenter clip closer in the embodiment of FIG. FIG. 4 is a side view showing a tenter clip closer in the embodiment of FIG. It is a perspective view which shows the tenter clip opener of FIG. It is a perspective view which shows another example of the tenter clip opener of this invention. FIG. 8 is a plan view showing the tenter clip opener of FIG. It is the schematic which shows the apparatus which detects and pinpoints the abnormal tenter clip by one Embodiment of this invention. It is a perspective view which shows a typical reference | standard clip detection sensor. FIG. 5 is an enlarged partial plan view showing a sensing unit of a representative device that assigns each tenter clip a unique number identifying the clip with respect to the tenter and a reference clip. FIG. 10 is a perspective view showing the tenter clip closer of FIG. It is the schematic which shows the stress change when the tenter clip conveyed in the tenter apparatus contacts with a clip drive device. FIG. 10 is a perspective view showing the tenter clip opener of FIG. FIG. 2 is a schematic diagram illustrating a conventional tenter device having a first tenter clip closer but not a second tenter clip closer. It is the schematic which shows the conventional disc type tenter clip closer.

[1] Tenter Clip Closer The tenter clip closer of the present invention is obtained by dividing the closing action into two tenter clip closers, that is, at least partially closing the tenter clip by the first upstream closer, and then the first tenter clip. Discovery that the second tenter clip closer downstream of the clip closer (machine direction of the web) allows the tenter clip to be operated repeatedly with less wear by more fully closing the clip and ensuring web gripping Based in part on. When the first tenter clip closer has a rectangular plate-like cam that is elongated in the machine direction, the cam has, for example, a curved surface and / or inclined surface that bends outwardly away from the web, and the upstream end of the cam is less than the downstream end. Far from the web. It has been found that an elongated curved cam should be able to provide a gradual closing force on the clip over a longer distance (and longer) than a disc-like closer. Since the force applied from the cam to the tenter clip is relatively small, the clip is less worn. Since tenter clips are generally actuated by the toggle movement (pivoting) of the clip arm, a relatively large force is effective to toggle the arm, especially on clips that are only partially closed by the first tenter clip closer. For application, the second tenter clip closer is preferably in the form of a freely rotating disc. In addition, the plate-like closer and the disk-like pressing member can be retracted when an abnormal force is applied to any one of the closers, for example, when a defective tenter clip is operated by the first or second tenter clip closer. Thus, it has been found advantageous to bias the first and / or second tenter clip closer with a suitable force (eg, a force generated by a spring, an air cylinder, or both).

  FIG. 15 shows a conventional tenter device that is commonly used to stretch a continuous plastic film in the plane direction (transverse direction and machine direction). The tenter includes a pair of loop-shaped rails 100 and 100 disposed on both sides of the film 400, a pantograph that circulates along the rail via a bearing, and a plurality of tenter clips 121 attached to the pantograph at regular intervals. The tenter clip closers 250 and 250 having a curved surface disposed in the entrance region of the tenter and curved slightly outward with respect to the machine direction, and disposed in the exit region of the tenter (also referred to as an open region), Elongated plate-like openers 300 and 300 having curved surfaces that are gradually bent inward with respect to the machine direction. The tenter is driven by driving means (for example, chain drive, belt drive, gear drive, etc.), and conveys the tenter clip 121 from the grip region at the tenter upstream end to the downstream stretch region.

  As the tenter clip 121 advances, its closing arm 121 'contacts the tenter inlet closer 250, the open clip 121 closes and grips the end of the film 400, and as the clip 121 advances in the machine direction, the film 400 Stretched. When the arm 121 ′ of the tenter clip 121 contacts the opener 300, the clip 121 opens and opens the stretched film 400.

  In order to hold the web (eg film) firmly with the tenter clip, the closer moves the arm so that the closing arm 121 'of the tenter clip 121 moves laterally away from the film. Since a considerable force is required to close the tenter clip that grips the web, the clip arm 121 ′ is severely worn by the closer 250, and particularly when both are made of metal, metal fine powder is generated, and the tenter The various films (such as the pivot axis of the tenter clip arm) that deteriorate and contaminate the stretched film. In particular, in the case of a battery separator film, the metal fine powder causes a short circuit in the battery, which is a problem. Furthermore, if a single strong force is used to actuate the clip arm 121 ', the pantograph and the bearing used to run it on the rail are also subjected to a relatively large load, and the pantograph and the pantograph and the tenter clip Further wear and deterioration occurs in the intervening bearings. This problem is significant, especially in the case of a defective cam in which the clip arm of the tenter clip 121 is in the open position, because not only the closer 250 but also the pantograph and the bearing are deformed or damaged by the large closing force of the closer 250 against the clip arm. I found out.

  In order to overcome this problem, Japanese Patent Laid-Open No. 59-48123 discloses a tenter clip closer shown in FIG. This closer is formed integrally with the wear disc 260 arranged so as to contact the clip lever 131, the arm 261 that rotatably supports the disc, the retainer 263 that holds the compression spring 262, and the retainer 263, A support bracket 264 that pivotally supports one end of the arm 261 is provided. One end of the retainer 263 is supported by the other end of the arm 261. The clip closer is retracted when an abnormal force is applied. In this device, the wear disc 260 rotates to press the clip lever 131 and close the tenter clip. When the arm 261 is pivoted by the force of an abnormal tenter clip (e.g., a tenter clip that fits in the opener as a result of an improper arm pivot on the clip), the disc 260 retracts.

  If only a disc-like closer is used as in the prior art, the contact time between the clip arm of the tenter clip and the disc is too short, and the clip arm is always pressed to fully close the clip and fully grip the web I found that I couldn't do it.

  FIG. 1 shows one embodiment of a tenter device modified to overcome this difficulty. In one embodiment, the improved tenter is attached to the pantograph with a pair of looped rails 1 provided on both sides of the film 4, a plurality of pantographs that circulate along the rails via bearings, and at regular intervals. The pair of tenter clip closer assemblies 2 are arranged in the inlet region of the tenter device, and the pair of tenter clip openers 3 are arranged in the outlet region of the tenter device. As the film 4 travels from upstream to downstream in the machine direction, the spacing between the rail pairs 1 increases within the stretching region of the tenter device. In this way, the film is stretched as the tenter clip that grips the film proceeds into the stretching zone.

  An example of a tenter clip that can be used in the present invention is shown in FIG. The tenter clip 11 includes (a) a C-shaped frame 11a, (b) a pivotable clip arm 11b pivotally attached to the frame, and (c) a pivotable gripping member 11c pivotally attached to the bottom of the clip arm. (D) Cylindrical upper teeth (having a gripping surface) 11d rotatably attached to the movable member (d) Cylindrical lower teeth 11e (clip closed) fixed to the lower arm of the C-shaped frame 11a A clamping surface for clamping the web together with the gripping surface.), (F) The first end is pivotally attached to the C-shaped frame 11a, and the second end is attached to the protrusion 110b of the clip arm 11b. It includes a pivoted tubular (preferably cylindrical) member 11f, and (g) a spring 11g (generally compressed) attached around the cylindrical member 11f to bias the clip arm 11b. When the spring 11g is appropriately selected, the clip arm 11b toggles between a position for gripping the web and a position for opening the web, that is, between a closed position and an open position. The first end of the clip arm 11b has a cam follower, and the clip arm 11b pivots about the axis 111b (clip arm pivot) by the cam of at least the first clip closer acting on the cam follower. 11b moves at least partially from the open position to the closed position. The tenter clip has a second cam follower that contacts the tenter clip opener in the open region of the tenter device. In one embodiment, the second cam follower is generally located near the first end of the pivotable arm of the tenter clip and faces the first cam follower.

  3-5 show in detail an example of one of a pair of tenter clip closer assemblies 2 disposed on both sides of the web. As described above, each tenter clip closer includes a first tenter clip closer and a second tenter clip closer downstream of the first tenter clip closer. In one embodiment, the tenter clip closer assembly 2 comprises: (a) a support arm 20 extending laterally toward the film 4 and having a leg at the outer end; and (b) two inverted J sandwiching the support arm 20 A support body 200 comprising letter-shaped side plates 200a and 200a and upper plates 200b and 200b for connecting the side plates in parallel; (c) a pivotable arm 21 having a pivot axis 21a (elongate rectangular shape, for example, support It can be pivoted like a seesaw around the pivot on the support at the lower end of the body 200, below the support arm 20.), (d) Attach to the first end of the pivotable arm 21 A first tenter clip closer (having a cam 2a having a curved surface that gradually bends outward with respect to the machine direction and inclined toward the film surface), (e) a second tenter clip closer 2b (for example, a disk-like shape that is rotatably attached to the U-shaped support member 211, and the first And the second tenter clip closer is attached to the pivotable arm 21 via the link member 210.), (f) biasing means 22 (eg spring or driven by compressed gas or liquid) A piston with a first end attached to the support 200 and a second end attached to a pivotable arm 21 so that the pivotable arm approaches the tenter clip (G) Stopper 201 to prevent the pivotable arm from pivoting beyond the stop point, and (h) Linear gauge 202 (for pivotable arm 21) Provided in the vicinity of the second end, and is used for measuring the position of the disk-like pressing member 2b, for example).

  Referring to FIGS. 3, 4 and 5, the first tenter clip closer 2a can have a curved surface that gradually protrudes outward while inclining inward and downward along the traveling direction of the clip 11. As a result, when the tenter clip 11 advances and the cam follower of the arm 11b of the opened clip 11 contacts the cam of the first tenter clip closer 2a (see FIG. 2 (a)), the clip arm 11b is removed from the film by the cam action. The clip 11 is pushed and pivoted, and the clip 11 is closed as shown in FIGS. 2 (b) and 2 (c). As the clip arm 11b pivots, the cylindrical member 11f also pivots, the bottom of the clip arm 11b is biased by the compression spring 11g, the clip 11 toggles and closes, and the film 4 is closed by the upper teeth 11d and lower teeth. Hold with 11e.

  The size, curvature, inclination angle and arrangement of the elongated plate-like closer 2a are selected so that the clip 11 is changed from an open state to a closed state in order to grip the film 4. Specifically, when the clip arm 11b is pivoted to an angle exceeding its neutral position (for example, a state where the apex of the projecting portion 110b is positioned on the axis of the cylindrical member 11f as shown in FIG. 2B), the clip arm 11b is compressed. Since the first clip closer 2a is closed by the bias pressure of the spring 11g, the cam size, curvature, inclination angle and arrangement of the first clip closer 2a should be set so that the clip arm 11b can be pressed to an angle exceeding the neutral position.

  Although it has been described that the cam of the first tenter clip closer 2a has a curved surface, this is not restrictive. The cam surface may be any surface as long as the cam follower of the tenter clip can be operated. In one embodiment, the cam is made of metal, but is not limited.

  After the clip 11 comes into contact with the first tenter clip closer and at least partially closes, the clip arm 11b further includes a second tenter clip closer 2b (generally a disc-shaped pressing member as shown). It pivots on contact. The disc of the second tenter clip closer 2b is generally rotatably supported on an inclined rotating shaft so that the outer surface thereof is in contact with the upper portion (generally, the cam follower portion) of the clip arm 11b. When the tenter clip is brought near the second tenter clip closer, the disc acts on the cam of the clip arm 11b to move the at least partially closed clip further to the closed position by a toggle motion. As the tenter clip advances in the machine direction, the 2b disk continues to rotate until it passes through the tenter clip closer assembly. The size and arrangement of the disk-like pressing member 2b are not limited, and can be selected so that the clip arm 11b is pressed deeply by the film 4 held by the clip 11. Although not limited, the diameter of the disk-shaped pressing member 2b may be in the range of about 10 to 30 cm, for example. Although not required, the 2b disk can be formed from an abrasion resistant resin (eg, hard nylon) for improved high durability.

  In one embodiment, for example, the second tenter clip closer 2b generates a pressing force that exceeds the contact resistance with the clip arm 11b to bias the clip arm 11b to an angle beyond the neutral position (for example, Select the bias pressure of the air cylinder) 22. It is desirable to increase the pressing force of the disk-like pressing member 2b so that the clip arm 11b is further pressed against the film 4 held by the clip 11. The force applied by the biasing means is such that the first or second tenter clip closer identifies a defective or abnormal tenter clip (e.g., by pivoting) while the defective tenter clip is being carried within the gripping area of the tenter device. ) Should not be so large as to prevent. For example, the bias pressure of the biasing means 22 is set to be weaker than the force applied when one or both of the first and second tenter clip closers come into contact with the defective tenter clip. In that case, for example, when an abnormal force is applied to the first or second tenter clip closer because the clip arm of the tenter clip is fixed in the upright (open) position, the pivotable arm 21 is as shown in FIG. And the tenter clip closer assembly moves away from the defective tenter clip. Such a situation can occur when the pivot of the tenter clip arm is corroded or worn. In fact, an appropriate force can be selected, for example by measuring with a load cell or strain gauge. A force of 10-300 N is required to close the tenter clip using the first and / or second tenter clip closer. Desirably, the force of the second tenter clip closer is greater than the force of the first tenter clip closer. In one embodiment, a force of 10-50 N is required to close the tenter clip using the first tenter clip closer, and 50-300 N to close the tenter clip using the second tenter clip closer. Is required, preferably 100 to 200 N.

  After at least partially closing the tenter clip arm with the first tenter clip closer, it can be securely and completely closed by contact with the second tenter clip closer, e.g. wear of toggle springs, pivot of the tenter clip arm It has been found that even tenter clips that are difficult to close with toggle motion due to wear, dirt or corrosion on the pivot axis of the clip arm can be closed. Further, since the clip arm 11b does not need to be completely closed with the first tenter clip closer, the clip arm cam follower and the tenter clip closer cam are compared with the cam / cam follower arrangement where the clip must be fully closed. The frictional force between them can be reduced. As a result, the relatively large force of the second clip closer can toggle the tenter clip to the fully closed position without significantly increasing the clip arm cam wear. When the tenter clip is in the fully closed position, there is less risk of damage to the tenter device. Also, the first and / or second tenter clip closers can move away from the defective or abnormal tenter clips, greatly reducing the risk of damage to the first tenter clip closer, the second tenter clip closer, the pantograph and the bearing. Or can be prevented.

  The present invention can be applied to tenter stretching of films having a wide range of thickness (for example, from a thickness of 10 μm or less to a thickness of 10 mm or more). A first or second tenter clip closer, or a tenter clip assembly comprising first and second tenter clip closers, is provided with a position sensor that senses the position of one or both of the closers while the tenter clip is closed. be able to. For example, the position of the disk-shaped pressing member 2b can be monitored using a linear gauge 202 having a scale plate 202a and a support member 202b, and the increase or decrease in the gap between the upper teeth 11d and the lower teeth 11e can be monitored. It can be monitored by measuring the position of 2b. When the gap exceeds a predetermined value, the bias pressure of the urging means 22 can be increased in order to increase the pressing force of the disk-like pressing member 2b. In this way, the pressing force of the disk-like pressing member 2b can be adjusted according to the thickness of the film 4.

  As shown in FIG. 2 (b) and FIG. 2 (c), when the clip 11 advances to the exit (opening area) of the tenter, the clip arm 11b is moved to the open position in order to toggle the clip 11 to the open position. 3 (film direction) can be pushed inward. When the clip arm 11b is tilted, the cylindrical member 11f rotates and the upper portion of the clip arm 11b is biased by the compression spring 11g (see FIG. 2 (a)), so the clip 11 opens the film 4. Although a normally opened clip is illustrated, the present invention is also applicable to a normally closed tenter clip. Although the present invention has been described above with respect to a tenter clip that is driven from the open position to the closed position and from the closed position to the open position by toggle movement (that is, an unstable neutral position compared to the open position and the closed position), The present invention is not limited to this, and a tenter clip having a stable or metastable neutral position can also be used in the present invention.

  It has been found advantageous to move the tenter device during the warm-up period when there is no film (e.g., lubricate and adjust the machine before starting the film stretching). In the present invention, for example, the first or second tenter clip can be retracted from the tenter clip by reducing the bias pressure of the urging means 22 and tilting the movable arm 21, so that it is also useful during the warm-up period. It is. When the tenter clip is closed during the warm-up period, the upper teeth 11d directly contact the lower teeth 11e without any film, and the upper teeth 11d and / or the lower teeth 11e are damaged. Thus, it is advantageous to operate the tenter clip closer or the tenter clip closer assembly (eg, as shown in FIG. 3) during the warm-up period.

[2] Tenter Clip Opener The tenter clip opener of the present invention is based on the discovery of a tenter clip opener that can rotate away from a defective or abnormal tenter clip. In one embodiment, the clip opener comprises an elongated fixed cam (not a rotating wheel or cam). The cam is fixed (does not rotate) but is pivotable less than 360 °, generally less than about 10 ° about the pivot axis. In general, while the clip is open, the cam moves against the biasing means in response to the force applied from the clip to the clip opener. Pressing force of the biasing means so that the cam is pressed sufficiently against the clip to release the clip, but if the clip is defective or abnormal, it does not prevent the tenter clip opener from pivoting away from the clip Select. In one embodiment, the clip opener cam has an elongated rectangular shape, eg, bent away from the tenter clip (and from the end of the web) in the vicinity of the cam. Such an elongated cam not only exerts a relatively small cam force over a long period of time, but can also be rotated away from the abnormal clip in the closed position so that the tenter clip can be opened more gently than a rotating wheel or fixed cam. I found out.

  As shown in FIG. 15, in order to release the web (eg film) from the tenter clip, the conventional tenter opener 300 contacts the drive means (eg pivotable clip arm) 121 ′ of the tenter clip 121 and the arm Is pushed in the opening direction (the tenter clip shown in FIG. 2 in the transverse direction toward the web). Since a considerable force is required to move the clip driving means from the closed position to the open position in order to open the web, the opener violently wears the clip arm 121 ', especially when both are made of metal, the metal fine powder is And may enter and degrade various parts of the tenter (eg, the pivot axis of the tenter clip arm). The stretched web is also contaminated with fine powder, which is particularly problematic for the film. Further, if a hard cam is used to operate the clip arm 121 ', the pantograph and the bearing are severely worn, cracked and deteriorated as described above. This problem has been found to be particularly serious for abnormal tenter clips (eg, tenter clips with arms in the open position). This is because the action of the clip opener 300 with respect to the clip arm in which the tenter clip 121 is fitted generates a large opening force that deforms or damages not only the opener 300 but also the pantograph and the bearing.

  In a rigid clip opener such as the rotating disk-shaped clip opener disclosed in Japanese Patent Laid-Open No. 2001-162681, the clip opener cannot be retracted when receiving an abnormally large force from the abnormal tenter clip. Can't solve the problem.

  In one embodiment, the clip opener of the present invention comprises a fixed cam pivotally attached to the tenter so that the clip opener is away from the abnormal tenter clip. For example, the clip opener has an elongated rectangular cam having a first end and a second end, the second end being attached to a pivotable arm. The pivotable arm has a first end attached to the cam and a second end attached to the biasing means. Axis between the first end and the second end. Depending on the arrangement of the cam and the pivotable arm, the first torque generated by the force of the abnormal tenter clip is the second torque (the biasing means acting on the second end of the pivotable arm). Force x distance between the pivot and the second end). When the first torque exceeds the second torque, the cam pivots away from the abnormal tenter clip.

  In another embodiment, the tenter clip opener has an elongated rectangular wedge shaped fixed cam. The first end of the cam is free to move and the second end (generally the wide end) of the cam engages the biasing means. The pivot is between the first end and the second end of the cam. When the clip is carried over the opener, the clip drive means contacts the vicinity of the upstream end of the cam, and then the contact point gradually advances toward the downstream end of the cam. As the tenter clip advances, the cam force gradually increases, driving the tenter clip from the closed position to the open position. As in the above embodiment, the first torque (equivalent to the cam force multiplied by the distance between the contact point of the tenter clip and the cam and the pivot) is the second torque (biased by the force of the biasing means). (Equal to the contact point between the means and the cam multiplied by the distance between the pivots). When an abnormally large force is applied by the abnormal tenter clip, the first torque exceeds the second torque, and the cam rotates to move away from the abnormal tenter clip.

  In one embodiment, the cam is in the form of an elongated rectangle or wedge having a cam surface that is curved away from the web from downstream to upstream to contact the drive means of the tenter clip. Although not required, the cam surface may be inclined at a positive angle with respect to a line perpendicular to the web surface. In other words, the first end of the cam closest to the tenter clip frame is inclined toward the web and the second end of the cam (the end furthest from the tenter clip frame) is from the tenter clip. It is tilted away. As shown in FIG. 6, the cam 3a is twisted by the slope gradually provided in the cam length direction. The cam material may be, for example, metal or wear-resistant resin, but is not limited.

  Although not essential, the cam pivots beyond a predetermined angular range of ± 10 °, ± 20 °, ± 45 ° or ± 60 °, for example, from the neutral position of the cam where the first and second torques are balanced. To prevent this, the tenter clip opener may further have a stopper, such as a mechanical stopper or a limiter. The tenter clip opener of the present invention preferably has a stopper for holding the plate-like opener in a fixed position. The biasing means may be an elastic body (for example, a spring) or a piston (for example, an air cylinder) driven by compressed gas or liquid.

The present invention will be described with reference to illustrated embodiments. As shown in FIG. 6, an example of one of the pair of tenter clip openers 3 includes the following members.
(a) Means for fixing the tenter clip opener to the tenter device (for example, the support member 30 extending from the first end far from the end of the film to the second end).
(b) A pivot support member (eg, a U-shaped member such as a U-shaped support member 304 fixed near the downstream side of the first end of the support arm 30).
(c) A pivotable arm 31 such as a Z-shaped arm shown in FIG. The illustrated arm includes a first portion 31a that is substantially parallel to the machine direction, a second portion 31b that is attached to the upstream end of the portion 31a and extends from the first end to the second end, and the downstream end of 31a. And a third portion 31c extending from a first end attached to the second end attached to the downstream end of the release cam. As shown, the pivot 31d has a pivotable arm located near the intersection of the first and second parts (eg, on the second part near the downstream end of the second part). The pivot support member (for example, a split pin) of (b) is provided.
(d) having a free first end and a second end downstream of the first end, the second end being a second end of the pivotable arm portion 31c. Linking cam 3a. As shown, the cam may be a curved surface that bends laterally away from the film from the first end to the second end. The curvature of the arc may be one or more of a parabola, a circle, an ellipse, and a hyperbola, for example. As shown in the figure, the cam is in the shape of an elongated rectangle (or a rectangular member), and may be twisted gently in a counterclockwise direction from the second end toward the first end. Torsion causes the cam surface to tilt, the longitudinal end of the cam close to the film is closer to the film, and the longitudinal end furthest from the film is away from the end of the film. In general, over the entire length of the cam, the cam surface is twisted by a fraction of a turn (eg 1/64, 1/32, 1/16 or 1/8 of a turn). The cam surface is gently inclined inward and downward with respect to the traveling direction of the tenter clip 11.
(e) The urging means fixing means such as the leg 301 can be attached to the downstream surface of the support arm 30.
(f) For example, as shown in the figure, fixing means such as a support base 302 extending downstream from the leg 301 in the machine direction may be further provided.
(g) Biasing means (for example, a first end attached to an L-shaped member 303 attached to the support base 302 and a second end attached to the downstream surface of the portion 31b of the movable arm 31) Spring 32). The biasing means applies a sufficient tension to keep the downstream portion of the cam 3a substantially parallel to the machine direction as shown.
(h) A stopper (for example, a mechanical stopper 33 provided on the support base 302) for preventing the portion 31b of the pivotable arm 31 from proceeding in the downstream direction under the tension of the urging means.
(i) Alarm means such as a limit switch 34 in the closed position under normal conditions (can be provided near the downstream surface of the part 31b of the pivotable arm 31). When the first torque defined above exceeds the second torque, the downstream surface of the pivotable arm pivots away from the limit switch and the limit switch is opened. By opening the limit switch, a signal can be sent to the automatic control means to stop the transport of the tenter clip.

  Referring to FIG. 6 again, the cam 3a has a curved surface that gently protrudes inward along the traveling direction (machine direction) of the tenter clip 11, and the curved surface is inclined inward and downward (for example, slightly twisted). ) When the clip 11 is carried to the vicinity of the opener, the opening cam follower of the clip 11b of the tenter clip 11 (see FIG. 2 (c)) that is completely or partially closed contacts the cam surface (film side) of the cam. As shown in 2 (a) and FIG. 2 (b), the clip arm 11b is pushed in the direction of the film, and the tenter clip 11 is at least partially opened to open the film. In other words, when the clip arm 11b pivots, the tubular member 11f rotates, and the first end of the clip arm 11b pressed by the pressing spring 11g toggles to bring the tenter clip 11 into the open position. Open film 4. The dimensions, curvature, inclination angle, and installation position of the elongated plate-like opener 3a are set so that the clip 11 can be easily toggled from the closed position to the open position. When the cam follower for releasing the clip arm 11b is pivoted by being pushed by the cam, the clip arm is moved from the closed position to the neutral position [FIG. 2 (b)] by the action of the biasing means (pressure spring 11g) [FIG. 2]. Toggle until (a)].

  Although this embodiment has been described with respect to a curved cam, the present invention is not limited to this. For example, the cam 3a may have a cam surface that is gently inclined inward with respect to the traveling direction of the tenter clip 11. The cam 3a may be metal, but is not limited.

  Referring to FIG. 6 again, the urging means (for example, the spring 32) acts on the pivotable arm 31 so as to resist the force applied to the cam 3a by the opening cam follower of the clip arm 11b. The force of the tension spring 32 that maintains the neutral position where the pivotable arm 31 is in contact with the stopper 33 is a reverse force substantially equal to the cam force that pivots the pivotable arm 31 about the pivot 31d. is there. In other words, when the first torque toggles from the closed position to the open position, the maximum cam force of the cam 3a applied to the cam follower for opening the tenter clip, the pivot axis 31d of the pivotable arm and the maximum cam It is multiplied by the distance from the point on the cam surface where the force is generated. Similarly, the second torque is obtained by multiplying the force of the biasing means acting on the portion 31b by the distance between the pivot 31d and the position where the biasing means engages with the portion 31b. The biasing means selects the second torque to slightly exceed the first torque for toggling to open the tenter clip. When a defective or abnormal clip is brought to the opener in a fully or partially closed state, an abnormally large cam force is generated, the first torque exceeds the second torque, and the pivotable arm 31 Moves away from the stopper 33, and the cam 3a moves away from the cam follower of the clip arm 11b, thereby reducing or preventing damage to the tenter device. Although not essential, the urging means 32 can be selected so that the cam 3a does not rotate with the minimum force required for the toggle movement from the open position to the closed position even when the tenter clip arm is actuated. When a tenter clip with a slightly hard toggle (for example, a tenter clip with a clip arm that has become slightly hard due to aging and normal wear) comes to the opener, the downstream surface of the portion 31b rotates away from the stopper 33. To do. In this embodiment, the spring 32 ensures that the cam 3a provides only the minimum force necessary to open the tenter clip. In this embodiment, since the minimum cam force required for the toggle movement of the clip is used, the clip, pantograph, bearing and the like are less likely to be worn. In order to prevent further rotation when the defective or abnormal tenter clip is carried to the cam 3a and to send an alarm signal, the second stopper and the second limiter are opposed to the first stopper and the first limit switch. Two limit switches can be used.

7 and 8 show a second embodiment of the tenter clip opener. In this embodiment, the tenter clip device 3 ′ has the following components.
(a) A support arm 35 having a pivot support member (for example, a split pin) at its end and extending in the lateral direction so as to be away from the film 4.
(b) An elongated wedge-shaped cam 3a ′ that can freely pivot about the first end inside the pivot support member of the support arm 35. The pivot is, for example, the illustrated split pin. The cam has a film surface and first and second surfaces substantially parallel to each other, and a cam surface slightly inclined in the direction of the film from the downstream (first) end to the upstream (second) end of the cam. Have. The cam has a fourth surface (substantially parallel to the machine direction when the cam is in the neutral position).
(c) an elongated rectangular member 350 (a first surface opposite the fourth surface of the cam; a second surface substantially in the same geometric plane as the first surface of the cam; A second surface and a third surface in substantially the same geometric surface).
(d) A tubular member 36 that passes through the plate member 350 and contacts (or almost contacts) the fourth surface of the cam 3a ′. A biasing means such as a pressing spring 360 is provided around the tubular member to press the cam surface of the cam 3a ′ against the cam follower for opening the tenter clip near the tenter clip opener.
(e) to hold the second surface of the member 350 in substantially the same plane as the first surface 3a ′ of the cam as the cam pivots about the split pin 31a ′. A stopper such as a stopper 351 attached to the second surface and the first surface 3a ′ of the cam (also serves as a guide means shown). The oblong slot 351a 'and the guide pin 30a' can be used, for example, to guide the cam as the cam pivots.
(f) Alarm means (for example, a limit switch 38 actuated by a member 37 attached to the second end of the cam to generate an alarm signal as described for the first embodiment).

  The opener of the second embodiment has a wedge-shaped cam that is gently inclined in the direction of the film as the tenter clip 11 advances in the machine direction. The selection of the pivot position and the adjustment of the biasing means are the same as described for the first embodiment. Since the tenter clip toggles from the closed position to the open position with the minimum necessary force, wear of the tenter clip and the tenter can be reduced. In one real 0 embodiment, the opener retracts when a force greater than 20 N, preferably 50 N, is applied.

  In a related embodiment, the cam 3a 'is a member having a curved cam surface as described for the first embodiment instead of a wedge. As in the first embodiment, the cam 3a ′ may be made of metal, although not limited thereto. Other materials such as wear resistant resin (eg, hard nylon) can be used for the cam surface or the entire cam.

  By appropriate adjustment, the biasing means 360 (eg, a piston driven by a spring or compressed gas or liquid) is set to oppose the cam force of the cam follower of the tenter clip against the cam 3a ′. The position where the biasing means 360 hits the fourth surface of the cam 3a ′ can be selected so that the cam force is maximized when the tenter clip crosses the tenter clip opener. Generally, this position is in the vicinity of the downstream end of the cam 3a ′ as shown. When this position is opposite to the position where the maximum force is applied from the cam follower to the cam surface, the lever arm of each force around the pivot axis 31a ′ is equal, and the first and second torques are compared with the first embodiment. It is relatively easy to calculate. Although not required, by appropriately selecting the biasing means 360, the pressing force of the damaged or abnormal clip arm 11b (adhered to the closed position) can damage one or more parts of the tenter device. Before it grows, the cam 3a 'is pivoted away from the abnormal clip against the biasing means.

  As described above, even in the second device, when an abnormally large force is applied from the tenter clip, the cam 3a 'pivots slightly away, thereby preventing or reducing wear of the tenter component including the clip. it can. The position where the tenter clip is opened by the toggle motion moves downstream along the surface of the cam 3a ′. When the need arises due to the aging of the device, the life can be extended by replacing the cam with a new one.

[3] Method and apparatus for detecting defective tenter clip The method and apparatus of the present invention for detecting a defective tenter clip will be described. One embodiment of the present invention relates to an apparatus and system for detecting an abnormal tenter clip (for example, a tenter clip whose opening / closing resistance is increased due to wear or accumulation of wear debris). The apparatus can be applied to the tenter. When the abnormal clip is brought near the tenter clip drive for opening and closing, the drive moves against the stopper due to resistance to the drive (generally toggle motion) of the abnormal clip. As a result of verifying the movement of the driving device, the clip driving device does not come into contact with the stopper in a clip that operates normally (the operation resistance is significantly less than that of the abnormal clip). The stopper performs two functions. First, the stopper prevents the tenter clip drive from moving further beyond the tenter clip beyond the limit point, and second, the stopper at the second limit point (which may be the same as the first limit point). Automatically drives the tenter clip counter and counts the number of tenter clips carried across the drive following an abnormal clip. The position of the abnormal tenter clip can be automatically or manually determined from the tenter clip in the tenter clip driving device to the abnormal tenter clip downstream in the traveling direction, or directly from a numerical value counted by other methods. The function of the stopper (means for preventing the drive from moving away from the tenter clip and means for generating an alarm and / or alarm signal to activate the counter) is the function of the connected stopper and alarm component (eg mechanical limit and electrical Type limit switch) or a single part combining them.

  The clip can be counted automatically by an automatic data processing device such as a computer. The tenter driving device is automatically controlled by the control means, and the tenter is automatically stopped after the stopper detects an abnormal clip. The control means and the counting means may be incorporated in an automatic process control device such as a computer.

Accordingly, another embodiment of the invention relates to a method for identifying abnormal tenter clips in a continuous stretch method of a polymer web. This method
(a) a step of conveying the polymer web to a stretching apparatus including the apparatus of the above embodiment,
(b) contacting the abnormal clip with the tenter clip driving device, moving the tenter clip driving device to the stopper, and operating the counter;
(c) stopping the tenter clip transport, and
(d) a step of identifying the abnormal tenter clip by counting the number of tenter clips between the drive device and the abnormal tenter clip by a counter; Automatic data processing / control means can be used to automatically stop the tenter drive. Due to the mechanical mechanism of the tenter, the machine does not stop immediately but continues for a period until inertia disappears. It is an advantage of the present invention that the counting means can continue to count tenter clips during this period so that abnormal clips can be identified even if they move away from the vicinity of the tenter clip driving device. In one embodiment, the method of the present invention can be performed when a drive comprising a stop and a counter is present in at least one of the opposing tenter clip closers according to the present invention. In this embodiment, abnormal clips can be identified before they are recirculated along the looped rail to the gripping area (which may damage the clip opener, pantograph, bearings, etc.). The system and method of the present invention has the advantage that it is driven only when the abnormal clip is in the vicinity of the drive, so it is more efficient than known systems and methods where the tenter clip is driven continuously throughout the system. is there.

  In another embodiment, (1) one of the tenter clips circulating in the same loop rail is used as a reference clip, and (2) a sensor that detects only the reference clip and a clip counter that counts all tenter clips are looped. (3) A signal including tenter information detected by the reference clip detection sensor and the clip counter is sent to an automatic data processing device (for example, a computer), and each of the tenters receives a reference clip signal there. The tenter clip is recorded with a unique serial number. (4) The tenter clip closer has at least one tenter clip closer located in the gripping area, and the tenter clip closer is (a) the tenter clip closer to the tenter clip closer ( Preferably downstream of the first closer The tenter clip cam follower (and clip arm) of the clip arm to at least partially close the tenter clip when gripped to the second closer A closing cam that rotates about a pivot; and (b) a stopper that holds at least one of the first and second closers in a fixed position, and (5) a closer cam relative to the cam follower of the tenter clip The force applied to the stopper of the tenter clip closer according to the operation of the tenter clip is measured by force sensing means (for example, a load cell or a strain gauge) for all tenter clips, and a signal from the sensing means is sent to the computer. If it is less than the predetermined threshold, the corresponding clip is recorded as an abnormal clip, and (6) Unique To identify the clip number or abnormal clip number, (a) the unique clip number of each tenter clip is associated with (b) the signal from the sensing means, and (7) the tenter clip opener is (a) the web At least one tenter clip opener (e.g., a fixed or rotating cam and / or wheel) and at least partially opening the tenter clip to release the tenter clip when the cam follower of the tenter clip contacts the clip opener A pivot that pivots the opener away from the tenter clip, and (b) a stopper that holds the opener in a fixed position, and (8) depending on the action of the cam and / or wheels of the opener on the cam follower of the tenter clip. The force applied to the stopper of the tenter clip opener Measures all tenter clips with a second force sensing means (eg load cell or strain gauge), sends a signal from the second force sensing means to the computer and responds if the sensed force is below a predetermined threshold (9) a unique clip number for each tenter clip and (b) a signal from the second sensing means to identify the unique clip number or abnormal clip number. And correspond. Having all of the above features at the same time, (4), (5) and (6) may be essential, and (7), (8) and (9) may be optional, and vice versa. All of the above features are applicable to the system, apparatus and method of the present invention. The features of this embodiment can be combined with the previously described embodiments.

  Although the features of the present invention have been described with reference to the drawings, the present invention is not limited thereto.

  FIG. 9 shows an example of an apparatus for carrying out the method of the present invention for detecting defect tenter clips. As described above, the tenter includes a pair of continuous loop rails 1 and 1, a pantograph, a tenter clip 11, tenter clip closers 2 and 2, and tenter clip openers 3 and 3. The pantograph has one arm that can freely expand and contract, and a plurality of parallel arms 10b supported by the arm. The tenter clip 11 is provided on the parallel arm 10b.

  In one embodiment, the clip count sensor 5a connected to the computer 6 is disposed outside the loop-shaped rail 1. As the clip count sensor 5a, an optical sensor (for example, an infrared sensor) can be used. The digital information detected by the clip count sensor 5a is sent to the computer 6.

  In one embodiment, the reference clip detection sensor 5b (detects only the reference clip 11 ′) is disposed inside the loop-shaped rail 1. As the reference clip 11 ′, one of a plurality of tenter clips 11 carried on the pantograph is selected. FIG. 10 shows an example of the reference clip detection sensor 5b. A dummy bolt 10c made of a magnetic material is attached to the inner end of the parallel arm 10b that supports the reference clip 11 ′. The reference clip detection sensor 5b is set at a position where the dummy bolt 10c passes near the sensor. The present invention will be described with respect to magnetic means for identifying a reference clip. Magnetic bolts / electromagnetic or magnetic sensors can be used to detect the reference clip, but are not limited, and other specific means (eg, optical means) can be used. When the electromagnetic or magnetic sensor is installed at an appropriate height, the dummy bolt 10c enters the detection range, but the parallel arm 10b is out of the detection range. Since the parallel arm 10b is generally a magnetic body, the electromagnetic or magnetic sensor generally detects the bolt 10c, but is installed at a height that does not detect the arm 10b. As shown in FIG. 9, the reference clip detection sensor 5b is connected to the computer 6. The digital information detected by the reference clip detection sensor 5b is sent to the computer 6 in the form of an analog signal that can be digitized, for example.

  In one embodiment, as shown in FIG. 11, the clip count sensor 5a and the reference clip detection sensor 5b are arranged so as to sandwich the rail 1, but this is not restrictive. The reference clip detection sensor 5b can be arranged downstream or upstream of the clip count sensor 5a. For example, the position of the clip count sensor 5a may be between the reference clip 11 ′ and the next clip 11 when the “dummy” bolt 10c is directly below the reference clip detection sensor 5b.

  The signal of the reference clip detection sensor 5b that has detected the dummy bolt 10c is sent to the computer 6 to reset the clip count value obtained from the clip count sensor 5a. The count value (integer) starting from the clip 11 next to the reference clip 11 ′ is sequentially recorded. In this way, a unique serial number is assigned to all tenter clips 11. The resetting of the count value and the assignment of the serial number to the clip 11 are repeated as the clip 11 is conveyed. The unique serial number assigned to the clip 11 at the position of the clip count sensor 5a can be sequentially displayed on the monitor panel 7 and stored in the computer.

  As described above, an abnormal clip (for example, a defective clip due to insufficient rotation of the clip arm 11b) can be detected by the tenter clip closer 2 and the opener 3.

  FIG. 12 shows one of the pair of tenter clip closer assemblies 2 in detail. This tenter clip closer assembly 2 is the same as the embodiment shown in FIGS. 3 to 5 except that it has sensing means 203 that engages the end of the stopper 201. The force sensing means 203 can be used to measure the force applied to the stopper 201.

  The force sensing means 203 can be provided at the end of the stopper 201 as shown. As shown in FIG. 12, when the closers 2a and 2b are in the fixed position, the rotating portion of the movable arm 21 is pressed upward by the biasing means 22, so that the closers 2a and 2b and any one of the clips 11 Even if there is a slight change due to contact, an almost constant force is applied to the stopper 201. When the abnormal clip contacts the closers 2a and 2b, due to the resistance of the abnormal clip to the toggle motion, a force exceeding the force applied when the normal clip closes is applied, and the force sensed by the force sensor 203 decreases. Therefore, the abnormal clip can be directly identified from the force measured by the sensor 203. In another embodiment, a strain gauge is used on the stopper 201 instead of the load cell 203.

As shown in FIG. 9, the signal of the load cell 203 can be sent to the computer 6. Digital information in the signals of all tenter clips 11 can be recorded in the computer 6. The force measured by the load cell 203 can be continuously monitored, and if the force falls below a predetermined threshold, the computer identifies the corresponding clip as an abnormal clip. For example, as shown in FIG. 13, the threshold value P ₁ is smaller than the force P ₁ measured when the normally functioning clip 11 is carried to the closer. When the force measured by the sensor is less than P ₁ (eg, 75%, 50% _, 25% or 10% of P ₁ ), the clip can be identified as an abnormal clip. However, it is not limited to this.

  FIG. 14 shows in detail one of a pair of tenter clip openers 3 that can be used in the present invention. This tenter clip opener 3 is the same as that of the embodiment shown in FIG. The force sensing means 330 can be used to measure the force applied to the stopper 33 during film stretching.

  A force sensing means (eg, load cell 330) can be attached to the end of the stopper 33. The load cell 330 contacts the portion 31b on the downstream surface of the movable arm 31. Since the movable arm 31 is biased by the tension spring 32 and resists the clip arm 11b, a substantially constant force is applied to the stopper 33 when the elongated plate-shaped opener 3a is normally in the fixed position (see FIG. 14). . However, when the abnormal clip is carried to the opener, a relatively large force is applied, and the force applied to the stopper 33 is reduced. As a result, an abnormal clip can be detected. A strain gauge can be used on the stopper 32 in addition to or in addition to the load cell 330, as in the case of a closer.

As shown in FIG. 9, all tenter clip 11 signals are sent from the load cell 330 to the computer 6 in order to constantly monitor the stress measured by the load cell 330. When the stress falls below a predetermined threshold P ₁ ′, the corresponding clip can be identified as an abnormal clip (eg, automatically). The threshold value P ₁ ′ is preferably set within a range of 75%, 50%, 25% or 10% of the initial stress P ₀ ′ (stress when the elongated plate-like opener 3a and the clip 11 are not in contact). .

  In one embodiment, abnormal clips can be detected by the tenter clip closer 2. In this case, when an abnormal clip was detected by the tenter clip closer 2, it was obtained by subtracting the number of clips between the clip count sensor 5a and the tenter clip closer 2 from the clip number counted by the clip count sensor 5a. The value is the number of the abnormal clip.

  In one embodiment, an abnormal clip can be detected by the tenter clip opener 3. In this case, when an abnormal clip is detected by the tenter clip opener 3, the number of clips between the clip count sensor 5a and the tenter clip opener 3 is subtracted from the clip number counted by the clip count sensor 5a. This value is used as the abnormal clip number.

  The number of the defective clip specified by the tenter clip closer 2 and / or the opener 3 is displayed on the monitor panel 7, the driving means is stopped, and the specified clip can be taken out from a specific position for replacement or repair.

Although not required, the device can be programmed to issue an alarm directly when a defective clip is detected by the tenter clip closer 2 and / or opener 3. For example, as shown in FIG. 13, suitably programmed to emit an alarm when the stress has dropped below a threshold P _1. The operator can stop the tenter after the alarm is triggered, check the status of the identified clip, and replace / repair the clip as needed. This can be done automatically, for example, by executing a command to stop the tenter when the force sensed by any of the sensing means falls below a threshold P ₂ lower than the threshold P ₁ . Although not required, the threshold P ₂ is 75% of P _{0, 50%,} can be set within a range of 25% or 10%.

  Although the present invention has been described with reference to the drawings, the present invention is not limited to the illustrated embodiments.

  The invention will be further described with reference to the following non-limiting embodiments.

1. an apparatus for stretching a polymer web,
(a) a driven conveyor having tenter clips that hold opposite ends of the web, convey the web in the machine direction from an upstream gripping region to a downstream stretching region in the apparatus, and are opened and closed by control;
(b) a first tenter clip closer located in a gripping region to at least partially close the tenter clip and grip the web;
(c) an apparatus further comprising a second tenter clip closer located downstream of the first tenter clip closer in the gripping region to close the tenter clip.

2. In the apparatus of embodiment 1, each tenter clip has a clamping surface and a pivotable clamping arm, the clamping arm having a first end having a cam follower and the tenter clip being at least partially closed And a second end having a gripping surface for gripping the web between the clamping surface.

3. In the apparatus of embodiment 1 or 2, the first tenter clip closer has a cam that pivots a cam follower of the tenter clip, so that when the tenter clip is carried to the first tenter clip closer, The tenter clip is a device that grips the web with a gripping surface and a clamping surface.

4. The device of any of embodiments 1-3, wherein the second tenter clip closer is in contact with a cam follower that is at least partially pivoted when the tenter clip is carried to the second clip closer. A device with a free disk.

5. The apparatus according to any one of Embodiments 1 to 4, wherein the conveyor is disposed in the stretching region so as to move along a path along which a tenter clip expands to stretch the web.

6. The apparatus according to any one of Embodiments 2 to 5, further comprising a pivotable member having a first end and a second end via a pivot, wherein the first of the pivotable members One or both of the first tenter clip closer and the second tenter clip closer are attached to the end of the pivotable member, the second end of the pivotable member acting perpendicular to the web surface device in a fixed position by a force F ₁ to.

7. The apparatus of embodiment 6, a first further caused around the axis of the member by a force F ₂ when there is a first or second tenter clip closer defects tenter clips to apply abnormal force F ₂ at The from the cam follower The pivotable member moves away from the tenter clip when the torque becomes equal to a second torque generated by a reverse force F ₁ centered on the biasing means.

8. In the apparatus of Embodiment 6 or 7, the cam of the first tenter clip closer is inclined in the direction of the web, and a curved surface extending in the upstream direction while bending away from the web in the gripping region. And a cam surface having an upper end.

9. The apparatus according to any one of Embodiments 6 to 8, wherein the cam is made of metal and the disc is made of wear-resistant resin.

10. The tenter clip closer according to any of embodiments 6-9, wherein a side surface of the disc contacts a cam follower that is at least partially pivoted.

11. A method of continuously stretching a polymer web,
(a) (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); and (ii) upstream Transporting the polymer web to a stretching device having a gripping region and a stretching region downstream of the gripping region, and comprising an opposing track for transporting a plurality of tenter clips,
(b) A cam follower of a series of opposing tenter clips in the gripping region is brought into contact with a pair of opposing first clip closers to at least partially close the tenter clip, thereby opposing the opposing ends of the web. Gripping sequentially with a pair of tenter clips, transporting the web to the stretching area,
(c) contacting a cam follower of a series of opposing tenter clip pairs with a second opposing clip closer pair located within the gripping region but downstream of the first clip closer;
(d) A continuous stretching method in which the web is transported to the stretching region along the opposing track, and the web is stretched in the stretching region.

12. A polymer web stretching device, wherein the web is transported to a stretching region in the machine direction while holding the opposite end, and a driven conveyor having a tenter clip that can be controlled to open and close, and at least one pivotable device. A tenter clip opener, wherein the tenter clip opener is configured to at least partially open the tenter clip to open the web, and to pivot the fixed cam away from the tenter clip. And a pivot connected to a fixed cam.

13. The apparatus of embodiment 12, wherein the tenter clip opener further comprises biasing means against the pivoting of the fixed cam.

14. In the apparatus of Embodiment 12 or 13,
(a) the tenter clip comprises a clamping surface and a pivotable clamping arm, the clamping arm between a first end having a cam follower and the clamping surface when the tenter clip is at least partially closed; A second end having a gripping surface for gripping the web;
(b) the device further comprises: (i) a gripping region upstream of the extension region; and (ii) at least one tenter clip closer located in the gripping region (when the tenter clip is carried to the tenter clip closer) And a closing cam for rotating the cam follower about the pivot axis in order to close the tenter clip at least partially and grip the web with a gripping surface and a clamping surface.
(c) When the tenter clip is transported to the tenter clip opener, the tenter clip opener cam is centered on the axis of the tenter clip to release the web gripped by the gripping surface and the clamping surface. A device for rotating the cam follower.

15. The apparatus of embodiment 14, wherein the tenter clip opener is located in an open region downstream of the extension region, the tenter clip opener further comprising a pivotable member, wherein the pivotable member is the tenter. A device having a first end to which a cam of a clip opener is attached and a second end connected to the biasing means, the pivot of the tenter clip opener being located on the pivotable member .

16. The apparatus according to any one of embodiments 12 to 15, wherein the cam of the tenter clip opener has an elongated rectangular plate shape or an elongated wedge shape.

17. In the apparatus of Embodiment 16, the cam and the cam follower are in contact with each other on the cam surface of the plate, and the cam surface moves laterally away from the film from a first end to a second end of the plate. A device that is a curved surface bent like this.

18. The apparatus of embodiment 17, wherein at least a part of the curved surface is a parabola, a circle, an ellipse, or a hyperbola.

19. The apparatus of embodiment 15, wherein the biasing means is a piston driven by one or more springs or liquid or gas.

20. In the apparatus of any of embodiments 13-19, the biasing means supports the downstream end of the cam of the tenter clip opener, and when the cam pushes the cam follower, the downstream of the cam of the tenter clip opener A device in which the end pivots away from the cam follower of the tenter clip against the biasing means.

21. In the device of any of embodiments 14-20, the tenter clip opener further includes at least one that limits movement of the cam about a pivot axis of the tenter clip opener to an angle of ± 45 ° from a neutral position. A device comprising a mechanical limiter.

22. A method of continuously stretching a polymer web, comprising:
(a) the polymer web; (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); (Ii) having a gripping region, a stretching region downstream of the gripping region, and an open region downstream of the stretching region, and transporting to a stretching device having a counter track that transports a plurality of tenter clips;
(b) contacting a cam follower of a series of opposing tenter clips in the gripping region with at least a pair of opposing first clip closers to at least partially close the tenter clips, thereby causing the opposing ends of the web to The web is transported to the stretching region by sequentially gripping with the opposing pair of tenter clips,
(d) transporting the web along the opposing track to the stretching area, where the web is stretched;
(e) contacting a cam follower of a series of opposing closed tenter clip pairs with at least one pair of opposing clip openers in the open region to at least partially open the tenter clip to sequentially open the gripping portion of the web; The clip opener includes: a fixed cam that at least partially opens the tenter clip to release the web; and a pivot connected to the fixed cam to pivot the fixed cam away from the tenter clip. A continuous stretching method comprising:

23. A polymer web stretching device comprising:
(a) a driven conveyor having a tenter clip that can be opened and closed under control while conveying the web to the stretching region in the machine direction while holding the opposite end;
(b) at least one tenter clip drive (at least partially opening and closing the tenter clip to grip or open the web), moving away from the tenter clip towards a stopper that prevents further movement by contact. )When,
(c) A stretching device including a counter that is automatically actuated by the stopper and counts the number of tenter clips carried to the tenter clip driving device after actuation.

24. In the apparatus of embodiment 23, the tenter clip drive device pivots the fixed cam to at least partially open the tenter clip to open the web and the fixed cam away from the tenter clip. A pivotable tenter clip opener comprising a pivot connected to the fixed cam and a biasing means against the pivot of the fixed cam.

25. In the apparatus of embodiment 24,
(a) the tenter clip comprises a clamping surface and a pivotable clamping arm, the clamping arm between a first end having a cam follower and the clamping surface when the tenter clip is at least partially closed; A second end having a gripping surface for gripping the web;
(b) the apparatus further comprises: (i) a gripping region upstream of the extension region; and (ii) at least one tenter clip closer located in the gripping region (when the tenter clip is transported to the tenter clip closer) And a closing cam for rotating the cam follower about the pivot shaft in order to close the tenter clip at least partially and grip the web with a gripping surface and a clamping surface.
(c) When the tenter clip is transported to the tenter clip opener, the tenter clip opener cam is centered on the axis of the tenter clip to release the web gripped by the gripping surface and the clamping surface. To rotate the cam follower,
(d) The stopper is connected to a load cell or a strain gauge, and the counter is operated by a signal from the load cell or the strain gauge.

26. In any of the embodiments 24 or 25, the tenter clip opener is located in an open region downstream of the extension region, and the tenter clip opener is further pivotable (on the cam of the tenter clip opener). A first end mounted and a second end coupled to the biasing means), wherein the pivot of the tenter clip opener is located on the pivotable member.

27. The apparatus according to any of embodiments 24-26, wherein the cam of the tenter clip opener is an elongated rectangular plate or an elongated wedge.

28. In the device according to any one of Embodiments 24 to 27, the cam and the cam follower are in contact with each other at a cam surface of the plate, and the cam surface extends from the first end to the second end of the plate. A device that is a curved surface that is curved away from the side.

29. The apparatus according to embodiment 28, wherein at least a part of the curved surface is parabolic, circular, elliptical, or hyperbolic.

30. The apparatus of any of embodiments 26-29, wherein the biasing means is a piston driven by one or more springs or liquid or gas.

31. In the device of any of embodiments 24-30, the biasing means supports the downstream end of the cam of the tenter clip opener, and when the cam pushes the cam follower, the downstream of the cam of the tenter clip opener A device in which the end pivots away from the cam follower of the tenter clip against the biasing means.

32. The device of any of embodiments 28-31, wherein the tenter clip opener further limits at least one cam movement about the pivot axis of the tenter clip opener to an angle of ± 45 ° from a neutral position. A device comprising a mechanical limiter.

33. A method for identifying abnormal tenter clips in a continuous stretch method of a polymer web,
(a) transporting the polymer web to a stretching device, and the stretching device (i) grips and transports the opposite end of the web and controls a plurality of tenter clips (abnormal tenter clips) controlled to open and close by a toggle motion. (Ii) at least one tenter clip drive device that opens and closes the tenter clip by toggle motion to open the web (the tenter clip drive device moves away from the tenter clip and moves toward the stopper). The tenter clip contacts the stopper when the abnormal tenter clip toggles with the driving device, but does not contact the stopper when the normally functioning tenter clip contacts the driving device, and the stopper is the tenter clip driving device. And (iii) the contact strike A counter that is automatically actuated by a padper and counts the number of tenter clips carried to the tenter clip drive after actuation;
(b) contacting the abnormal clip and the tenter clip driving device to move the tenter clip driving device to the stopper, and operating the counter;
(d) A method of identifying an abnormal tenter clip by counting the number of tenter clips between the driving device and the abnormal tenter clip with the counter.

34. In the method of embodiment 33, the stretching device further comprises: (iv) a pair of continuous rails disposed on opposite sides of the web for transporting the tenter clip from the gripping region through the downstream stretching region to the open region ( At least one drive device in the gripping region is a tenter clip closer, and at least one drive device in the open region is a tenter clip opener), and (v) at least one reference tenter clip; ) A reference clip sensor for detecting the reference clip; (vii) a second counter for counting the number of tenter clips that have passed through the second counter after the reference clip; and (viii) the second counter. A data processing device for reading and identifying each of the plurality of tenter clips with respect to the reference clip; And,
The method further includes
(c) Stop the tenter clip transport,
(e) The number counted by the second counter is associated with the number of each clip, so that each clip is identified by a unique number representing the number of clips between each clip and the reference clip,
(f) A method for determining a unique number of the abnormal clip.

35. In the method of Embodiment 33 or 34, when an abnormal clip contacts the tenter clip opener, the abnormal clip is subtracted by subtracting the number of clips between the second clip counter and the tenter clip opener. Determine a unique number and if the abnormal clip contacts the tenter clip closer, determine the unique number of the abnormal clip by subtracting the number of clips between the second clip counter and the tenter clip closer Method.

36. In any one of the methods of Embodiments 33 to 35, the plurality of tenter clips are provided on a pantograph, and the pantograph includes a freely expandable / contractable pantograph arm and a plurality of parallel pantograph arms supported by the pantograph arm. An arm and a magnetic reference member on a parallel arm close to the reference clip, the pantograph circulates along the looped rail, and the reference clip sensor has the reference member within its detection range. A method which is a magnetic sensor arranged so that the parallel arms do not enter.

Claims (4)

A polymer web stretching device comprising:
(a) a driven conveyor having tenter clips that hold opposite ends of the web, convey the web in the machine direction from an upstream gripping region to a downstream stretching region in the apparatus, and are opened and closed by control;
(b) a first tenter clip closer located in a gripping region to at least partially close the tenter clip and grip the web;
(c) further comprising a second tenter clip closer located downstream of the first tenter clip closer in the gripping region for closing the tenter clip to grip the web. apparatus. A continuous stretching method for a polymer web,
(a) (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); and (ii) upstream Transporting the polymer web to a stretching device having a gripping region and a stretching region downstream of the gripping region, and comprising an opposing track for transporting a plurality of tenter clips,
(b) A cam follower of a series of opposing tenter clips in the gripping region is brought into contact with a pair of opposing first clip closers to at least partially close the tenter clip, thereby opposing the opposing ends of the web. Gripping sequentially with a pair of tenter clips, transporting the web to the stretching area,
(c) contacting a cam follower of a series of opposing tenter clip pairs with a second opposing clip closer pair located within the gripping region but downstream of the first clip closer;
(d) A method for continuously stretching a polymer web, comprising transporting the web along the opposite track to the stretching region, and stretching the web in the stretching region. Polymer web stretching device, driven conveyor having tenter clips holding said web in the machine direction while holding opposite ends and capable of opening and closing under control, and at least one pivotable tenter clip An opener, wherein the tenter clip opener includes a fixed cam that at least partially opens the tenter clip to open the web, and the fixed cam for pivoting the fixed cam away from the tenter clip. And a biasing means against the pivot of the fixed cam. A continuous stretching method for a polymer web,
(a) the polymer web; (i) a plurality of tenter clips having a clamp surface and a pivotable clamp arm (the clamp arm has an upper end portion having a cam follower and a lower end portion having a gripping surface); (Ii) having a gripping region, a stretching region downstream of the gripping region, and an open region downstream of the stretching region, and transporting to a stretching device having a counter track that transports a plurality of tenter clips;
(b) contacting a cam follower of a series of opposing tenter clips in the gripping region with at least a pair of opposing first clip closers to at least partially close the tenter clips, thereby causing the opposing ends of the web to The web is transported to the stretching region by sequentially gripping with the opposing pair of tenter clips,
(d) transporting the web along the opposing track to the stretching area, where the web is stretched;
(e) contacting a cam follower of a series of opposing closed tenter clip pairs with at least one pair of opposing clip openers in the open region to at least partially open the tenter clip to sequentially open the gripping portion of the web; The clip opener includes: a fixed cam that at least partially opens the tenter clip to release the web; and a pivot connected to the fixed cam to pivot the fixed cam away from the tenter clip. A continuous stretching method for a polymer web, comprising:

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