JP6212512B2 - Film transport device and film stretching machine - Google Patents

Description

  Embodiments of the present invention relate to a film transport apparatus that transports a film to a predetermined position with a belt, and a film stretching machine that transports and stretches the film to a clip holding position with the film transport apparatus.

  A film stretching machine that grips and stretches a film formed from a thermoplastic resin or the like with a clip is known (see Patent Document 1). Such a clip-type film stretching machine includes a film transport device that transports a film to a clip gripping position. The film conveying device conveys the film while sucking it onto a perforated endless belt (hereinafter simply referred to as a belt) that is stretched between a driving pulley and a driven pulley and circulates between these pulleys. Below the belt (inside the ring), an air chamber is arranged in which the inside air is sucked by the suction device, and a hole that can communicate with the hole of the belt is formed in the ceiling of the air chamber. Therefore, when the inside air of the air chamber is sucked by the suction device, the internal pressure of the air chamber is reduced and the outside air is sucked into the air chamber through the hole in the ceiling portion that communicates with the hole in the belt. As a result, the film is sucked onto the belt. At that time, it is necessary to consider the suction state of the film with respect to the belt in order to stably convey the film to the clip holding position.

  For example, in the film transport apparatus disclosed in Patent Document 1, the air chamber is divided into a plurality (for example, three). Each of the divided air chambers is provided with a suction device that sucks the inside air and a valve that allows the outside air to flow into the room. When the conveyance of the film is started, the inside air of the air chamber is sucked by all the suction devices with all the valves closed. When the belt circulates and the film is conveyed, the hole of the belt and the hole of the ceiling portion of the air chamber communicating with the belt are closed by the film from the upstream side to the downstream side in the conveyance direction. Since the air chamber in which the hole in the ceiling portion communicating with the hole in the belt is closed with the film has a large internal pressure, the force with which the film is attracted to the belt is increased at the position where the air chamber is disposed. When the internal pressure of the air chamber is reduced to a predetermined pressure, the valve of the air chamber opens and the outside air flows into the room. This prevents the film from being sucked excessively on the belt and prevents the film from being smoothly conveyed even above the air chamber in which the hole in the ceiling communicating with the hole in the belt is blocked with the film. It is out.

JP 2000-255855 A

  However, in the film transport device disclosed in Patent Document 1, as described above, a plurality of air chambers must be provided with suction devices, respectively, and the number of piping systems increases, which tends to increase the size of the device. In addition, since the power consumption increases by the number of suction devices, the environmental load is increased accordingly.

  Therefore, a film transport apparatus capable of stably transporting a film while avoiding an increase in the size of the apparatus and an increase in environmental load, and a film stretching machine including the film transport apparatus are provided.

According to the embodiment, in the film stretching machine that grips and stretches the film with the clip, the transport device that transports the film to the position where the film is gripped is bridged between the driving pulley and the driven pulley, and between these pulleys. A perforated endless belt that circulates the film and a driving device that drives the driving pulley, and is partitioned and lined by a partition wall from the upstream side to the downstream side in the film conveying direction, and the back surface of the film conveying surface of the endless belt A plurality of air chambers with a perforated ceiling facing each other, a suction device that sucks the inside air of the most upstream air chamber and sucks the film onto the endless belt, and an upstream air chamber adjacent to the partition wall and downstream A valve mechanism that sequentially communicates with the air chamber on the side as the film is conveyed, and uniformly adjusts the internal pressure of the upstream air chamber and the internal pressure of the downstream air chamber. The valve mechanism is provided in the partition, provided in the most downstream air chamber, the first valve for venting the internal air of the downstream air chamber to the upstream air chamber adjacent to the partition, and the air chamber And a second valve for venting outside air. A plurality of holes that can communicate with each other are formed in the endless belt and the ceiling of the air chamber. The first valve is formed before all the holes in the ceiling of the upstream air chamber communicating with the endless belt among the adjacent air chambers sandwiching the partition wall provided with the first valve are closed with the film. open. The second valve opens before all the holes in the ceiling portion of the most downstream air chamber communicating with the endless belt are closed with the film.

  According to the film transport apparatus of the embodiment, the film can be transported stably while avoiding an increase in the size of the apparatus and an increase in environmental load. Therefore, by transporting the film with such a film transport apparatus, it is possible to reduce the size of the film stretching machine and reduce the environmental load.

The schematic plan view which looked at the film extending machine of embodiment from the upper part. The schematic side view which shows the mechanism immediately after the film conveyance start of the film conveying apparatus of embodiment. The schematic side view which shows the mechanism in film conveyance of the film conveyance apparatus of embodiment. The schematic side view which shows the mechanism immediately before the film conveyance stop of the film conveying apparatus of embodiment. It is a figure which shows the valve mechanism of embodiment, Comprising: (a) is a side view which shows the state which the valve closed, (b) is a figure which shows the state of (a) from the direction of arrow A5, (c) is a valve The side view which shows the open state. The schematic plan view which looked at a part of film stretching machine of the modification which made arrangement | positioning of a film conveyance apparatus different from embodiment from upper direction.

  Hereinafter, a film transport apparatus according to an embodiment and a film stretching machine including the film transport apparatus will be described with reference to FIGS. 1 to 4. In the following description, the direction orthogonal to the transport direction of the film 10 (corresponding to the direction from left to right in FIG. 1) parallel to the film plane is the left-right direction, and the direction orthogonal to both the transport direction and the left-right direction is the direction. The vertical direction. The left-right direction is defined toward the transport direction of the film 10, and the up-down direction is defined according to the direction of gravity. Accordingly, the X direction shown in FIGS. 1 to 4 corresponds to the forward direction, the Y direction corresponds to the left direction, and the Z direction corresponds to the upward direction.

  FIG. 1 is a schematic plan view of a film stretching machine 1 according to this embodiment as viewed from above. The film stretching machine 1 is a processing machine that grips and stretches a film 10 formed of a thermoplastic resin or the like with a clip (not shown). In this case, the film 10 is stretched in both the horizontal direction (left-right direction) and the vertical direction (conveyance direction).

  As shown in FIG. 1, the film stretching machine 1 has a circuit 11 for circulating a large number of clips that hold a film 10 to be stretched. The circuit 11 is disposed on each side of the film 10 in the width direction (left-right direction). In the circuit 11, the circuit members are driven by drive members (for example, sprockets) 12 provided on the inlet 1a side and the outlet 1b side, respectively, and move along the guide rails. The clip is provided on the circulating member, and grips the side end in the width direction of the film 10 at a predetermined position P (hereinafter referred to as a clip gripping position) P on the inlet portion 1a side, and the gripped film 10 is held at the outlet portion 1b. release.

  In the film stretching machine 1, a preheating area 13, a stretching area 14, and a heat treatment area 15 of the film 10 are sequentially configured from the inlet 1a to the outlet 1b. The preheating area 13, the stretching area 14, and the heat treatment area 15 are provided with a heating device 16 so that the film 10 can be appropriately heated according to the heating conditions of the areas 13 to 15.

  In the preheating area 13, neither the transverse stretching nor the longitudinal stretching of the film 10 is performed, and only the preheating of the film 10 is performed. Therefore, in the preheating area 13, the circuits 11 on both sides in the width direction of the film 10 are separated by a distance corresponding to the width dimension of the film 10 when the lateral stretching is started. In this case, the separation distance of the circuit 11 in the preheating area 13 is the smallest in all the areas, and the circuits 11 on both sides in the width direction of the film 10 are arranged in parallel with each other over the entire area of the preheating area 13. .

  In the stretching area 14, the film 10 heated in the preheating area 13 is stretched laterally and longitudinally. Accordingly, in the stretching area 14, the circuits 11 on both sides in the width direction of the film 10 are gradually separated from the preheating area 13 toward the heat treatment area 15, and these circuits 11 are arranged inclined from the parallel state. In this case, the separation distance of the circuit 11 in the stretching area 14 is a distance corresponding to the width dimension of the film 10 at the start of stretching (boundary with the preheating area 13), and a stretching end (heat treatment). At the boundary with the area 15, the distance corresponds to the width dimension of the film 10 when the lateral stretching is finished.

  In the heat treatment area 15, neither the transverse stretching nor the longitudinal stretching of the film 10 is performed, and the heat treatment of the film 10 stretched in the stretching area 14 is performed. Therefore, in the heat treatment area 15, the circuits 11 on both sides in the width direction of the film 10 are separated by a distance corresponding to the width dimension of the film 10 when the transverse stretching is finished. In this case, the separation distance of the circuit 11 in the heat treatment area 15 is the largest in all areas, and the circuit circuits 11 on both sides in the width direction of the film 10 are arranged in parallel with each other over the entire area of the heat treatment area 15. .

  Such a film stretching machine 1 includes a film transport device 2 in order to stably transport the film 10 to be stretched from the entrance 1a to the clip gripping position P. The film stretching machine 1 is characterized by the film transport apparatus 2, and the film transport apparatus 2 of the present embodiment will be described below. 2 to 4 show a schematic configuration of the film transport device 2 of the present embodiment.

  As shown in FIG. 2 to FIG. 4, the film transport device 2 places the film 10 to be stretched on an endless belt (hereinafter simply referred to as a belt) 3, and places the leading portion 10 a in the transport direction of the film 10 at a clip gripping position. Transport to P. The belt 3 has a large number of holes 3a penetrating from the surface (the conveyance surface of the film 10) to the back surface thereof, and is opened to the atmosphere through these holes 3a. The belt 3 is looped between the driving pulley 4 and the driven pulley 5 and circulates between them.

  The driving pulley 4 is driven by a driving device 6. As the driving device 6, an electric motor or the like is applied. For example, the motor shaft and the rotating shaft of the driving pulley 4 are connected by a gear, and the driving pulley 4 is rotated. The driven pulley 5 is driven by the rotational force of the driving pulley 4 being transmitted by the belt 3, and rotates in the same direction as the driving pulley 4. The drive pulley 4 is disposed at the position of the sprocket 12 on the inlet 1a side of the film stretching machine 1, in other words, at the position where the film 10 is taken into the film stretching machine 1. The driven pulley 5 is disposed at a position slightly behind the clip gripping position P of the film 10.

  As a result, the film 10 can be carried on the belt 3 over the length from the inlet 1a of the film stretching machine 1 to the clip gripping position P. The drive device 6 is supplied with power from a power source and is controlled by a control device (not shown) to drive the drive pulley 4 in synchronization with the rotation of the sprocket 12. Further, the driving device 6 is not particularly limited to an electric motor as long as it is a device capable of supplying a rotational driving force to the driving pulley 4.

  In this embodiment, the width of the belt 3 is made smaller (less than half) compared with the width of the film 10 before stretching, and the belt 3 is formed along both edges in the width direction of the film 10 and both edges. A pair is arranged in parallel with the part. When the width of the film 10 before stretching is considerably larger (three times or more) than the width of the belt 3, the film 10 is disposed along both edges in the width direction of the film 10 and in parallel with both edges. One or a plurality of belts 3 may be arranged in parallel between the belts 3. Thereby, even if it is the wide film 10, the attitude | position at the time of conveyance can be stabilized reliably.

  Below the belt 3 (inside the ring), an air chamber 7 capable of allowing air (atmosphere) to flow into and out of the internal space is disposed along the transport direction of the film 10. The air chamber 7 is a rectangular box having a width substantially the same as or larger than the width of the belt 3 and extending between the driving pulley 4 and the driven pulley 5. A pair of 10 is disposed along both edges in the width direction and parallel to both edges.

  The air chamber 7 includes a plurality of compartments in which the internal space is partitioned by a partition wall 70 from the upstream side to the downstream side in the conveyance direction of the film 10. In the present embodiment, the air chamber 7 is partitioned into four compartments by the partition wall 70, but the number is not particularly limited. In the following description, when these compartments partitioned by the partition wall 70 are distinguished, they are referred to as air chambers 71, 72, 73, 74 in order from the upstream side. In this case, the air chambers 71 to 74 are partitioned by the partition wall 70 so that their lengths (dimensions in the film transport direction) are substantially the same. However, the lengths of the air chambers 71 to 74 may be different. For example, the lengths of the air chambers 71 to 74 may be sequentially increased so that the air chamber 71 is the shortest and the air chambers 72 to 74 are the longest. .

  The air chambers 71 to 74 have a plurality of holes 7b in the ceiling portion 7a. The hole 7b is formed so as to penetrate the ceiling portion 7a up and down, and opens the internal space of the air chambers 71 to 74 to the atmosphere. The air chambers 71 to 74 are arranged with the ceiling portion 7 a facing the back surface of the belt 3 (the surface opposite to the conveyance surface of the film 10). Thus, the air chambers 71 to 74 can appropriately communicate the hole 7 b of the ceiling portion 7 a with the hole 3 a of the belt 3 during the circulation of the belt 3.

  The air chamber 71 located at the uppermost stream has a connection port 7d with a suction device (such as a vacuum pump) (not shown) formed in the bottom 7c. As a result, the air chamber 71 is adapted to suck inside air from the connection port 7d by the suction device. Note that the connection port 7d may be formed not on the bottom 7c of the air chamber 71 but on the side wall. The connection port 7d is connected to the suction device via a connector and a hose. When the inside air of the air chamber 71 is sucked from the connection port 7d by the suction device, the internal pressure of the air chamber 71 is reduced from the atmospheric pressure. When the internal pressure of the air chamber 71 is reduced in this way, outside air flows into the air chamber 71 from the hole 7b of the ceiling portion 7a when communicating with the hole 3a of the belt 3, and the film 10 is sucked onto the belt 3. It is done. Thereby, when the film 10 is conveyed above the air chamber 71, the posture of the film 10 can be stabilized.

  The air chamber 7 includes a valve mechanism 8. The valve mechanism 8 sequentially communicates the upstream air chamber 7 and the downstream air chamber 7 adjacent to each other with the partition wall 70 as the film 10 is conveyed, and the internal pressure of the upstream air chamber 7 and the downstream air chamber 7 are communicated with each other. The internal pressure of the air chamber 7 on the side is kept uniform. In the present embodiment, the valve mechanism 8 includes a first valve 81 and a second valve 82. The first valve 81 is provided in the partition wall 70, and the upstream air chamber 7 (for example, the air chamber 71) adjacent to the partition wall 70, and the downstream air chamber 7 (for example, the air chamber 72). Vent the inside air. Specifically, a total of three first valves 81 are provided, one for each of the three partition walls 70. These first valves 81 sequentially vent the air chamber 71 and air chamber 72, the air chamber 72 and air chamber 73, and the air chamber 73 and air chamber 74 as the film 10 is conveyed. On the other hand, the second valve 82 is provided in the most downstream air chamber 74, and allows the outside air to be vented to the air chamber 74.

  In the present embodiment, the first valve 81 and the second valve 82 have the same valve structure. FIG. 5 shows the valve structure of the first valve 81, but the valve structure of the second valve 82 is the same. Note that the first valve 81 and the second valve 82 may be configured differently, and this is not specifically excluded.

  As shown in FIG. 5, the first valve 81 has a spring 83 and opens and closes by the urging force of the spring 83. In this case, the first valve 81 includes a wall portion 84 having a vent hole 84a, a plate portion 85 that contacts the wall portion 84 and can close the vent port 84a, and the wall portion 84 and the plate portion 85 are connected by a spring 83. And a support portion 86 to be assembled via the.

  The wall portion 84 is fastened and fixed to the bottom portion 7c of the air chamber 7 with a bolt 88 via an attachment member 87 such as a bracket. In the present embodiment, the planar shape is formed in a rectangular shape slightly corresponding to the shape of the longitudinal section (cross section in the YZ plane) of the air chamber 7. The plate portion 85 is formed in a planar shape (for example, a circular shape) that can completely cover and close the vent hole 84 a and is slightly smaller than the planar shape of the wall portion 84.

  The support portion 86 includes a cylindrical body 86a, a shaft body 86b inserted into the cylindrical body 86a, and a movable body 86c that can slide along the shaft body 86b. The cylindrical body 86 a is fixed to the wall portion 84 by being fitted into a hole 84 b that penetrates the center portion of the wall portion 84. A plate portion 85 is assembled to one end side (left end side in FIG. 5A) of the shaft body 86b inserted into the cylindrical body 86a. On the other hand, the movable body 86c is screwed to the other end side (the right end side in FIG. 5A) of the shaft body 86b inserted into the cylindrical body 86a. The spring 83 surrounds the outer periphery of the shaft body 86b, and one end side is fixed to the cylindrical body 86a and the other end side is fixed to the movable body 86c. As described above, the support portion 86 is configured as a screw type in which the wall portion 84 and the plate portion 85 are assembled via the spring 83.

  As a result, the spring 83 can be expanded and contracted by the tightening degree of the movable body 86c with respect to the shaft body 86b, and the urging force of the spring 83 can be adjusted. The shaft body 86b inserted into the cylinder body 86a is slidable with respect to the cylinder body 86a, and the wall section 84 and the plate section 85 are obtained by sliding the shaft body 86b according to the tightening degree of the movable body 86c. Can be adjusted by the biasing force of the spring 83. Specifically, the contact pressure between the wall portion 84 and the plate portion 85 can be increased (increase the contact force) by tightening the movable body 86c and contracting the spring 83. Conversely, by loosening the movable body 86c and extending the spring 83, the contact pressure between the wall portion 84 and the plate portion 85 can be lowered (the contact force is weakened).

  The first valve 81 has the plate portion 85 side on the upstream side in the transport direction of the film 10 (left side in FIG. 5A) and the movable body 86c side on the downstream side (the same figure (a ) Is positioned on the right side) and is fixed to the bottom 7c of the air chamber 7. In the present embodiment, the wall portion 84 and the plate portion 85 of the first valve 81 correspond to the partition wall 70. Although FIG. 5 shows a form in which the first valve 81 constitutes the entire partition wall 70, the first valve 81 may constitute only a part of the partition wall 70.

  Note that the second valve 82 having the same valve structure as the first valve 81 has a wall portion 84 fixed to the bottom portion 7 c of the air chamber 74. In this case, the second valve 82 has the bottom portion of the air chamber 74 with the plate portion 85 side corresponding to the upstream side in the conveyance direction of the film 10 and the movable body 86c side corresponding to the downstream side with the wall portion 84 interposed therebetween. It is arranged outside 7c. The second valve 82 may be fixed to the side wall portion instead of the bottom portion 7c of the air chamber 74.

  Here, the effect | action of the internal pressure adjustment of the air chamber 7 by the 1st valve 81 and the 2nd valve 82 is demonstrated with reference to FIGS.

  When the film 10 is conveyed by the film conveying device 2, the hole 3a of the belt 3 and the hole 7b of the ceiling portion 7a of the air chambers 71 to 74 communicating with the hole 3 are closed with the film 10 from the upstream side to the downstream side in the conveying direction. It will be peeled off. In the state shown in FIG. 2, among the holes 7 b formed in the ceiling portion 7 a of the air chamber 71 located at the uppermost stream, two holes 7 b located on the upstream side are blocked by the film 10, and downstream from it. The four holes 7b located on the side communicate with the holes 3a of the belt 3 and are open to the atmosphere. In this state, since the inside air of the air chamber 71 is sucked from the connection port 7d by the suction device, the film 10 is sucked to the surface of the belt 3 (the transport surface of the film 10). At the same time, outside air flows into the air chamber 71 from the hole 7b communicating with the hole 3a, and the internal pressure of the air chamber 71 is not greatly reduced, so that the force that the film 10 is attracted to the belt 3 (in other words, the suction pressure) ) Is maintained properly.

  In this state, since the internal pressure of the air chamber 71 is lower than the internal pressure (atmospheric pressure) of the adjacent air chamber 72 across the first valve 81 that is the partition wall 70, the force generated by the internal pressure difference (pressing force) ) Acts on the first valve 81 from the air chamber 72 side (downstream side). However, in this embodiment, since the urging force of the spring 83 is larger than the pressing force, the plate portion 85 comes into contact with the wall portion 84 as shown in FIGS. The first valve 81 between 71 and the air chamber 72 is in a closed state.

  FIG. 3 is a diagram illustrating a state where the film 10 is further conveyed above the air chamber 71. In the state shown in FIG. 3, five holes 7 b located on the upstream side are blocked by the film 10, and only one hole 7 b located on the most downstream side communicates with the hole 3 a of the belt 3 and is opened to the atmosphere. It is in a state. In this state, the internal pressure of the air chamber 71 is further reduced as compared with the state of FIG. 2, while the internal pressure of the air chamber 72 remains unchanged at the atmospheric pressure, so that the internal pressure difference between the two chambers increases. In the present embodiment, the biasing force of the spring 83 is made smaller than the pressing force applied to the first valve 81 due to the internal pressure difference in this state. Accordingly, as shown in FIG. 5C, the plate portion 85 is separated from the wall portion 84 by receiving such a pressing force, and the first valve 81 between the air chamber 71 and the air chamber 72 is opened. Thereby, the air chamber 71 and the air chamber 72 are communicated with each other via the first valve 81.

  When the first valve 81 is opened, outside air flows into the air chamber 72 from the holes 3a of the belt 3 and all the holes 7b of the ceiling portion 7a of the air chamber 72 communicating with the belt 3 as shown in FIG. The inflowing outside air, in other words, the inside air of the air chamber 72 passes through the first valve 81 and is vented from the air chamber 72 to the air chamber 71 and is sucked by the suction device from the connection port 7d of the air chamber 71. Therefore, although the film 10 is sucked to the surface of the belt 3, the internal pressure of the air chamber 71 is not greatly reduced, so that the force that the film 10 is sucked to the belt 3 above the air chamber 71 (suction pressure). Can be kept appropriate.

  When the film 10 is further conveyed from the state shown in FIG. 3, the conveyed film 10 sequentially passes above the air chamber 72, the air chamber 73, and the most downstream air chamber 74. When the film 10 is transported above the air chambers 72 to 74, the same state as that when transported above the air chamber 71 described above occurs, so that the air chamber 71 is between adjacent air chambers. The first valve 81 sequentially causes the internal pressure adjustment action similar to that between the air chamber 72 and the air chamber 72.

  In FIG. 4, five holes 7 b located on the upstream side are blocked by the film 10 above the air chamber 74, and only one hole 7 b located on the most downstream side communicates with the hole 3 a of the belt 3. It is a figure which shows the state open | released to air | atmosphere. In this state, the internal pressure of the air chamber 74 is further reduced as compared with the state corresponding to FIG. 2, while the external pressure of the air chamber 74 does not change at atmospheric pressure, so the internal / external pressure difference of the air chamber 74 increases. In the present embodiment, the biasing force of the spring 83 is made smaller than the pressing force applied to the second valve 82 due to the internal / external pressure difference in this state. Therefore, as in the case shown in FIG. 5C, the plate portion 85 is separated from the wall portion 84 by receiving such a pressing force, and the second valve 82 between the air chamber 74 and the outside (outside the bottom portion 7c). Will be open. As a result, the air chamber 74 and the outside communicate with each other via the second valve 82.

  When the second valve 82 is opened, outside air flows into the air chamber 74 from the opened second valve 82. The outside air that has flowed in, that is, the inside air in the air chamber 74 is vented from the air chamber 74 to the air chamber 73, the air chamber 72, and the air chamber 71 through the first valve 81 and sucked from the connection port 7 d of the air chamber 71. Aspirated by the device. Therefore, although the film 10 is sucked to the surface of the belt 3, the internal pressure of the air chamber 74 is not greatly reduced, so that the force that the film 10 is sucked to the belt 3 above the air chamber 74 (suction pressure). Can be kept appropriate. Then, the leading portion 10a of the conveyed film 10 reaches the clip gripping position P in a state where the suction pressure is properly maintained in this way.

  When the leading portion 10a of the film 10 reaches the clip gripping position P, the film 10 proceeds to the exit portion 1b of the film stretching machine 1 while being stretched while being sequentially gripped by the clips. Therefore, since it is not necessary to transport the film 10 with the film transport apparatus 2, the film transport apparatus 2 stops. Specifically, after the second valve 82 is opened, the rotation of the drive pulley 4 is stopped, the circulation of the belt 3 is stopped, and the suction of the internal air in the air chamber 71 by the suction device is stopped. Such stop control of the film transport device 2 may be performed by a control device (not shown). Further, when stopped, the film transport device 2 is preferably retracted (for example, lowered) by an elevating device (not shown).

  As described above, according to the film transport apparatus 2 of the present embodiment, the upstream and downstream air adjacent to each other with the partition wall 70 interposed therebetween is provided with the valve mechanism 8 (the first valve 81 and the second valve 82). The chamber 7 can be sequentially communicated with the conveyance of the film 10. Thereby, the internal pressure of the air chamber 7 of an upstream side and a downstream side can be adjusted uniformly. Therefore, the film 10 can be stably transported to the clip holding position P without being excessively attracted to the belt 3, and can be transported smoothly and stably to the clip gripping position P. As a result, the stretching accuracy of the film 10 in the film stretching machine 1 can be increased.

  In particular, in this embodiment, since only the suction device that sucks the inside air of the most upstream air chamber 71 needs to be provided, it is not necessary to increase the size of the film transport device 2 without particularly increasing the number of piping systems. In addition, power consumption by the suction device can be suppressed, and the environmental load does not need to be increased. Therefore, it is possible to reduce the size and environmental load of the film transport device 2 and, consequently, the film stretching machine 1.

  In addition, since the valve mechanism 8 (the first valve 81 and the second valve 82) has a simple and simple structure that opens and closes by the biasing force of the spring 83, the environmental load on the valve mechanism 8 can be reduced. Can do. However, the valve mechanism 8 is not a mechanical type that does not require external control as in the present embodiment, but may be configured to open and close by electronic control, for example, a valve mechanism using a pressure switch for detecting vacuum pressure and a motor valve. Absent. As a result, the internal pressures of the upstream and downstream air chambers 7 can be adjusted with higher accuracy. In this case, since the operation control of the suction device can be performed with high accuracy, it is also possible to reduce the environmental load of the film transport device 2 and the film stretching machine 1 as a result.

  In the present embodiment, the first valve 81 is a ceiling portion of the upstream air chamber 7 communicating with the belt 3 among the adjacent air chambers 7 across the partition wall 70 provided with the first valve 81. All holes 7b in 7a begin to open before being closed with film 10. The second valve 82 starts to open before all the holes 7b of the ceiling portion 7a of the most downstream air chamber 74 communicating with the belt 3 are closed. That is, before the first valve 81 and the second valve 82 are opened, all the holes 7b of the ceiling portion 7a of the air chamber 7 serving as a trigger are closed with the film 10 (for example, immediately before). The tightening degree of the movable body 86c is adjusted so that the pressing force applied to the plate portion 85 of the 81 and the second valve 82 and the biasing force of the spring 83 are balanced. Accordingly, the adjacent air chambers 7 can be surely communicated with the partition wall 70 interposed therebetween, and the inside air or the outside air of the downstream air chamber 7 can be smoothly ventilated to the upstream air chamber 7.

  In the present embodiment described above, the belt 3 and the air chamber 7 of the film transport device 2 are arranged in parallel with both edges in the width direction of the film 10. For example, as shown in FIG. In addition, the belt 3 and the air chamber 7 of the pair of film transport apparatuses 2 may be gradually spaced apart from the upstream side in the transport direction of the film 10 toward the downstream side. Thereby, the facing area of the film 10 and the belt 3 can be enlarged at the time of conveyance start. For this reason, the force (suction pressure) at which the film 10 is attracted to the belt 3 above the air chamber 71 at the start of conveyance can be increased. Therefore, the posture of the film 10 at the start of conveyance can be more reliably stabilized.

  Moreover, in this embodiment mentioned above, although the film conveying apparatus 2 is conveying the film 10 of extending | stretching object from the entrance part 1a of the film stretching machine 1 to the clip holding position P, the use of the film conveying apparatus 2 is this Not limited. For example, in the exit part 1b of the film stretching machine 1, it is also conceivable that the film 10 is transported by the film transporting apparatus 2 from the position where the clip releases the stretched film 10 to the position where the film is unloaded by the exit roll.

  As mentioned above, although embodiment of this invention was described, embodiment mentioned above is shown as an example and is not intending limiting the range of invention. The above-described novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Film stretcher, 2 ... Film conveying apparatus, 3 ... Endless belt (belt), 3a ... Hole, 4 ... Drive pulley, 5 ... Driven pulley, 6 ... Drive apparatus, 7 (71-74) ... Air chamber, 7a ... ceiling part, 7b ... hole, 7c ... bottom part, 7d ... connection port, 8 ... valve mechanism, 10 ... film, 70 ... partition wall, 81 ... first valve, 82 ... second valve, 83 ... spring, 84 ... Wall part, 84a ... vent, 84b ... hole, 85 ... plate part, 86 ... support part, 86a ... cylindrical body, 86b ... shaft body, 86c ... movable body, 87 ... mounting member, bolt ... 88.

Claims (5)

In a film stretching machine that grips and stretches a film with a clip, a transport device that transports the film to a position gripped with the clip,
A perforated endless belt which is bridged between a driving pulley and a driven pulley and circulates between these pulleys to convey the film;
A driving device for driving the driving pulley;
A plurality of air chambers with a perforated ceiling portion facing the back surface of the film conveying surface of the endless belt, and aligned and partitioned by a partition wall from the upstream side to the downstream side in the film conveying direction;
A suction device that sucks the inside air of the most upstream air chamber and sucks the film onto the endless belt;
The upstream air chamber and the downstream air chamber adjacent to each other across the partition wall are sequentially communicated with the conveyance of the film, and the internal pressure of the upstream air chamber and the internal pressure of the downstream air chamber are A valve mechanism that adjusts uniformly,
The valve mechanism is provided in the partition, and is provided in a first valve that vents the internal air of the downstream air chamber to the upstream air chamber adjacent to the partition, and the downstream air chamber. A second valve for venting outside air to the air chamber,
A plurality of holes that can communicate with each other are formed in the endless belt and the ceiling of the air chamber,
Of the air chambers adjacent to each other across the partition wall provided with the first valve, all the holes in the ceiling portion of the upstream air chamber communicating with the endless belt are the film. Open before it ’s closed,
The film conveying apparatus, wherein the second valve opens before all the holes in the ceiling portion of the most downstream air chamber communicating with the endless belt are closed with the film. The film transport apparatus according to claim 1 , wherein the first valve and the second valve have springs and are opened and closed by a biasing force of the springs. The first valve and the second valve include a wall portion having a vent, a plate portion that comes into contact with the wall portion to close the vent port, and the wall portion and the plate portion are connected to the spring. A screw-type support part assembled through
The film conveying apparatus according to claim 2 , wherein the support portion adjusts a contact pressure between the wall portion and the plate portion by expanding and contracting the spring according to a tightening condition of a screw. The film conveying apparatus according to any one of claims 1 to 3 , wherein the air chambers are arranged in a pair along at least both edges in the width direction of the film. A film transport device according to any one of claims 1 to 4 , comprising:
A film stretching machine, wherein a film transported by the film transporting device is gripped and stretched by a clip.

Images