JP2010208074A - Drawing machine for sheet material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing machine for a sheet material, which minimizes the level difference of a link running surface and makes the variation of a high draw ratio possible in a simple constitution. <P>SOLUTION: In the drawing machine for the sheet material in which a plurality of gripping devices which grip the end of the sheet material of a thermoplastic resin are guided by guide rails for guidance which are delivered from the side of an inlet and arranged to be parallel in the advance direction and to be spread, stretch the sheet material, detach the sheet material after stretching, and return to the inlet side through the side of an outlet, a first flexible rail joint having a plurality of slits in the longitudinal direction on a rail side surface and a second flexible rail joint adjacent to the first rail joint are arranged in the bending part of the boundary between the parallel state and the spreading state of the guide rails for guidance. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet-like material drawing machine for drawing a sheet-like material such as a thermoplastic resin film.

  Conventionally, in a sheet-like material drawing machine using an endless link device, as a method of making the guide rail variable, for example, as described in JP-A-10-337773 (Patent Document 1), a leaf spring is used. As described in Japanese Patent Application Laid-Open No. 2004-122640 (Patent Document 2), a rail using a multi-joint guide rail that is curved in a substantially arc shape and is continuously connected to the linear shape portion and the arc-shaped rail. There are known ones that can change the angle.

  In addition, as described in Japanese Patent Application Laid-Open No. 2006-1988554 (Patent Document 3), a flexible rail joint in which a plurality of staggered slits are arranged vertically in the longitudinal direction of the rail side surface corresponding to the bending position of the guide rail is provided. It is known that the rail angle can be changed by using it.

JP 10-337773 A JP 2004-122640 A JP 2006-198854 A

  However, in the method of providing and guiding two guide rails at a predetermined interval in Patent Document 1, when a leaf spring is applied to the bent portion, both ends of the leaf spring are fixed and the guide rail is angled. Of the two leaf springs, the inner leaf spring bends more convexly than the outer leaf spring due to the difference in the radius of curvature between the outer leaf spring and the inner leaf spring. Therefore, it is necessary to slide one of the leaf springs. In this case, it is necessary to slide in the direction in which the gap is vacant. However, if the gap is generated, a step may be formed when the guide roller travels, which may hinder the running stability of the link device and may shorten the life of the link device. is there.

  Moreover, in the prior art using the multijoint guide rail of patent document 2, a sudden angle change will arise in a joint part by rail bending, and the driving | running | working of a smooth guide roller will be inhibited. If the multi-joint guide rail block is made smaller, this angle change can be reduced, but the size of the block cannot be made too small due to the structure, so abrupt angle change due to bending of the block at the joint part should be reduced. There is a problem that the running stability of the traveling body is hindered.

  In these prior arts, if the guide roller is increased in outer diameter, it is considered that there is substantially no problem even if a step of a relatively mm order occurs. It is important to reduce the size and weight of the body, and the guide roller cannot be increased in diameter. Moreover, in the case where processing accuracy (stretching accuracy of the sheet-like material) is required, the accuracy cannot be maintained unless the level difference is on the order of μm, which is equal to the processing accuracy. Therefore, in order to enable a highly accurate stretching operation, it is necessary to eliminate as much as possible the step that hinders the traveling stability of the traveling body.

  On the other hand, as a means for solving the above problems, Patent Document 3 is provided with a flexible rail joint provided with a plurality of staggered slits to reduce the step on the link running surface as much as possible and to make the stretching ratio variable. Although there is a product stretching machine, no consideration is given to a film having a large stretch ratio. Further, in the text of this prior art, when a larger extension angle is required (6 ° or more in this embodiment), for example, it is described that a plurality of flexible rail joints are arranged. It lacks concreteness with abstract expression.

  An object of the present invention is to provide a sheet-like material drawing machine that makes it possible to change the high draw ratio with a simple configuration by minimizing steps on the link running surface as much as possible in view of the above-mentioned drawbacks of the prior art.

  The object is to provide an endless link device provided with a plurality of gripping devices at both ends of the sheet-like material for gripping end portions of the thermoplastic resin sheet-like material, and the endless link device is formed in a folding scale. A plurality of isometric link devices, which are driven by sprockets on the inlet side and outlet side, are fed from the sprockets on the inlet side, and are guided by guide rails arranged in a parallel state and a divergent state in the traveling direction. In a sheet-like material drawing machine configured to extend a sheet-like material, remove the sheet-like material after drawing, and return to the inlet-side sprocket via the outlet-side sprocket, the guide guide rail is parallel and divergent. A first flexible rail joint having a plurality of slits in the longitudinal direction of the rail side surface at the bent portion of the state boundary, and a wake of the first flexible rail joint It is achieved by placing the second flexible rail joints.

  Further, the above object is achieved by arranging each of the flexible rail joints at the bent portion of the entrance / exit portion of the sheet-like material in the sheet-like material drawing machine described above.

  Further, in the sheet-like material drawing machine described above, when the length in the longitudinal direction of the section in which the plurality of slits of the flexible rail joint is arranged is a, the object of the above-mentioned purpose is to set the interval between the flexible rail joints to a or more. Or a to 3a.

  The object is achieved by providing a common driving device for driving the first flexible rail joint and the second flexible rail joint to bend in the sheet-like material drawing machine described above.

  According to the present invention, since the guide rail for link travel can be moved with a simple structure, it is possible to change the high stretch ratio, improve the travel stability of the link device, and Cost reduction and life extension can be achieved.

It is a top view which shows the flexible rail joint of this invention Example. It is the figure which represented typically the example of arrangement | positioning and rail arrangement | sequence of a flexible rail joint of this invention Example and a prior art example. It is the figure which represented typically the example of arrangement | positioning of a flexible rail joint of this invention Example, and a rail arrangement | sequence. It is explanatory drawing of the drive of the flexible rail joint of this invention Example. It is a top view of the simultaneous biaxial stretching machine of the example of the present invention. It is sectional drawing which shows the equal length link of the extending | stretching machine of FIG. It is the figure which modeled the guide rail and isometric link of FIG. It is a top view explaining the bending angle of a flexible rail joint. It is a figure showing the relationship between the bending angle of a flexible rail joint, and a stress ratio. It is a figure showing the relationship between the measurement site | part of the overhang | projection side of a flexible rail joint, and stress. It is a figure showing the relationship between the measurement site | part of the compression side of a flexible rail joint, and stress.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the simultaneous biaxial stretching machine which is the basic form of this invention is demonstrated using FIGS.

  FIG. 5 is an example of a plan view of a simultaneous biaxial stretching machine as a basic form of the present invention, and FIG. 6 is a schematic cross-sectional view of a link device of the simultaneous biaxial stretching machine shown in FIG. A configuration of a sheet-like material drawing machine 1 according to an embodiment of the present invention and a link device used therefor will be described. A sheet-like material drawing machine 1 shown in FIG. 5 includes a conveyance space 2 in which a sheet-like material made of a thermoplastic resin that extends in the center is conveyed, and a link guide rail 3 that forms a closed path. Endless link devices 4 and 5 are arranged on both sides of the conveyance space 2 in the sheet conveyance direction in order to grip and convey each of the both end portions of the sheet material while being driven around.

  In these endless link devices 4 and 5, sprockets 6, 7 and 8 arranged on the inlet side and the outlet side of the sheet-like material in the conveyance space 2 are connected to a driving device such as a motor (not shown). The link device 200 meshed with 7 and 8 slides on the link guide rail 3 and moves.

  That is, as shown in FIG. 6, an endless link device 4 or 5 having a plurality of gripping devices 202 for gripping the end portion of the sheet-like material on both sides of the sheet-like material (part of the link and endless link on one side in the figure). Is provided with a link device 200 configured by connecting a plurality of equal-length links 201 formed in a fold-like shape to be closed in an annular shape. The link device 200 is driven by a sheet-like material entrance-side sprocket 6 or 7 and travels on the link guide rail 3 to open / close means (not shown) such as an open / close guide provided at the entrance of the conveyance space 2. As a result, the gripping device 202 is opened and closed to grip the sheet-like material, and travels on the rail on the conveyance side of the link guide rail 3 while heating the sheet-like material to a temperature necessary for stretching in the preheating region 9.

  Furthermore, in the extension area 10 of the wake, guided by the link guide rail 3 arranged in a divergent shape in the traveling direction, the gripping pitch between the gripping devices 202 is gradually expanded from P1 to P2, A sheet is stretched simultaneously in two directions. Thereafter, the sheet-like material is heat-set at a predetermined temperature in the heat-fixing region 11, and then the gripping device 202 is opened and closed by an opening / closing means (not shown) such as an opening / closing guide provided at the outlet to remove it from the sheet-like material. Then, the removed sheet is allowed to proceed as it is. Further, the link device 200 is driven by the sprocket 8 on the outlet side, travels on the return side rail of the link guide rail 3, and returns to the inlet side sprocket 6.

  The link guide rail 3 is composed of a pair of rails 205 and 206 which are a pair of beams on the inner and outer peripheral sides, each of which is formed of a beam-like member having a substantially rectangular cross section arranged so as to be convex as shown in FIG. It is configured. For the rail on the conveyance side where the equal-length link 201 travels while gripping the sheet-like object, the rail 205 on the outer peripheral side closer to the sheet-like object is connected to the grip device 202 for gripping the sheet-like object. A link shaft 207 is disposed, and a joint link shaft 208 having no gripping device 202 is disposed on the inner rail 206.

  Link shaft 207 and link shaft 208 are connected by link plates 209 and 210. Bearing holders 211 and 212 having bearing rollers 211a and 212a, which are first rolling bearings, are connected to the lowermost ends of the link shafts 207 and 208, and both sides of the bearing holders 211 and 212, that is, outer circumferences of the bearing rollers 211a and 212a. A pair of radial bearings 213 [213a, 213b] and 214 [214a, 214b], which are a pair of second rolling bearings, are attached to the portion. The flanged radial bearings 213 and 214 roll on both side surfaces of the rails 205 and 206 that restrict the movement of the isometric link 201, and the upper surface of the rails 205 and 206 and the flanges of the flanged radial bearings 213 and 214 contact each other. It arrange | positions so that the dead weight of the equal length link 201 may be hold | maintained.

  FIG. 7 schematically shows guide rails and isometric links installed in a plurality of beds (FIG. 5 shows two sections, hereinafter referred to as joints) located in the extension region 10. The crossing angle (θ) between the link plate and the guide rail differs between θ1 and θ2 in the closed state and the open state. Even at this time, the radial bearings 213 and 214 with the flanges supported by the bearing holders 211 and 212 always act on the both sides of the rails 205 and 206 by the action (rotation) of the bearing rollers 211a and 212a with respect to the link shafts 207 and 208. Change (pivot) so as to be positioned substantially vertically. That is, it is orthogonal to the longitudinal direction of the guide rails 205 and 206.

  Accordingly, since the pair of radial bearings with flanges can always be at a constant angle with respect to the guide rail, it does not depend on the intersection angle (θ) between the link plates 209 and 210 and the rails 205 and 206 or the width of the guide rail. The link device 200 can be made to travel.

  FIG. 7 shows a state where the amount of stretching in the MD direction (magnification in the longitudinal direction of the sheet-like material) is larger than 1.0. That is, on the right side of the figure, the rail 206 and the rail 205 approach each other, and the link opening angle of the isometric link 201 is increased. Thereby, the sheet-like material is stretched in the traveling direction (the gripping device is omitted in the figure). In addition, a flexible rail joint as described in Japanese Patent Application Laid-Open No. 2006-198854 can be used to connect the guide rails not shown in the figure and the guide rails in the figure, whereby a plurality of joints can be connected. Can be arranged endlessly.

  Next, the bending angle of the guide rail (flexible rail joint) will be described with reference to FIG. 8 to FIG. In the guide rails 205 and 206 for guiding the sheet-like material to be extended, one flexible rail joint 51 shown in FIG. 8 is disposed at the bent portion of the boundary between the parallel state and the divergent state. FIG. 8 is a plan view of the rail joint on the film entrance side among the flexible rail joints provided at four locations in total in the guide rails 205 and 206 arranged on one side of the sheet-like material. In the drawing, the left side corresponds to the preheating side (sheet inlet side), and the right side corresponds to the stretching side. FIG. 8A shows the rail state (straight state) when the draw ratio in the transverse direction (TD direction) is 1.0, and FIG. 8B shows the draw ratio in the transverse direction (TD direction). Is a rail state of ε times (ε> 1.0), that is, a state in which the flexible rail joint 51 is bent from the guide rails 205 and 206 at an angle θ.

  The flexible rail joint 51 has a plurality of slits 52 formed in a zigzag shape at the center of both side surfaces of the rail, the preheating side end is fixed to the fixed bed 50, and the extended side end is the movable bed 55 or Fixed to 56 and restrained. Note that a circle with a reference numeral 53 represents a fixing bolt (other circles are also considered).

  The fixed bed 50 and the movable bed 55 or 56 are rotatably pin-coupled at the central portion of the slit of the flexible rail joint 51, and when the movable beds 55 and 56 move by a predetermined amount in the extending direction (the lower side of the drawing). As shown in FIG. 8 (b), it is convex on the inside, that is, on the sheet-like object side (upper side of the drawing), and is concave on the outer side (lower side of the drawing).

  9 to 11 are diagrams showing the relationship between the bending angle of the flexible rail joint 51 and the stress. The stress measurement site (number) is the central part of the side surface in the slit cut direction, and the number and positional relationship are as follows. As shown in FIG. Is an even display (2k). All stress values were evaluated as absolute values. Note that k is a variable of the number of slit groups 1 to n.

  10 and 11, the flexible rail joint 51 has a higher stress value as it is closer to the left fixed end, and the stress tends to decrease as it goes to the right side. Moreover, this tendency becomes more prominent as the angle increases. Even at a bending angle of 9 degrees where the stress value is high, it is 1/10 or less of the material breaking strength, and there is no practical problem (however, the slit width needs to be larger than 0.3 mm of the conventional example).

  FIG. 9 is arranged using the following formula in order to clarify the relationship between the tendency and the angle.

  That is, the lower the ratio of the stress (σ) between the tension side (2k-1) and the compression side (2k) adjacent to each other, the more the slit is bent. From this figure, the stress ratio suddenly increases when the bending angle of the flexible rail exceeds 6 degrees, and becomes an unstable region such as a crack in the rail.

  Next, a detailed configuration of the embodiment of the present invention will be described. FIG. 1 is a plan view of the entrance side of a flexible rail joint film of a guide rail for guiding a sheet extending portion. FIGS. 2 and 3 are schematic views of the arrangement of the flexible rail joint. FIG. 4 is a flexible rail joint. It is explanatory drawing of the drive of.

  In the guide rails 205 and 206 arranged on one side of the sheet-like material in FIG. 1, the first flexible rail joint 51 and the bent portions of the boundary where the straight state (parallel state) is expanded toward the end, respectively, A second flexible rail joint 61 is provided adjacent to (or downstream of the first flexible rail joint 51). In the drawing, the left side corresponds to the preheating side (sheet inlet side), and the right side corresponds to the stretching side. FIG. 1 (a) shows the rail state when the draw ratio in the transverse direction (TD direction) is 1.0 (straight state), and FIG. 1 (b) shows the draw ratio in the transverse direction (TD direction). Is a rail state of ε times (ε> 1.0), that is, a state in which the flexible rail joints 51 and 61 are bent from the guide rails 205 and 206 at angles θ3 and θ4, respectively.

  The first flexible rail joint 51 has a plurality of slits 52 formed in a zigzag shape at the center of both side surfaces of the rail. The preheating side end is fixed to the fixed bed 50 and the extension side end is divided. It is fixed to the movable bed 62 or 63. The second flexible rail joint 61 has the same structure as the first flexible rail joint 51, the preheating side end is fixed to the split movable bed 62 or 63, and the extension side end is fixed to the movable bed 55 or 56. And is restrained. Note that the circle 53 is a rail fixing bolt (other circles are the same).

  The fixed bed 50 and the split movable bed 62 or 63 are configured such that the movable bed 55 or 56 is pin-coupled so as to be freely rotatable at the slit central portion of the first flexible rail joint 51 or the second flexible rail joint 61. 62, 63 and the movable beds 55, 56 are moved in the extending direction (the lower side of the drawing) by a predetermined amount, as shown in FIG. 1 (b), become convex on the inside, that is, the sheet-like object side (the upper side of the drawing). It is concave on the outside (the lower side of the drawing).

  Here, the first flexible rail joint 51 is bent with respect to the guide rail 205 by an angle θ3, and the second flexible rail joint 61 is bent with respect to the first flexible rail joint 51 by an angle θ4. . And each angle (theta) 3 and (theta) 4 is each set to 6 degrees or less, and avoids the unstable area | regions where a rail (flexible rail joint) cracks.

  Also, as shown in FIG. 1, when the length in the longitudinal direction of the section in which the plurality of slits 52 are arranged is a, the interval between the slit groups of the first and second flexible rail joints 51 and 61 is as close as possible. This is convenient because the angle can be obtained at a shorter distance, but considering the arrangement space of the fixing bolt 53 and the mechanism space for moving the bed, the interval is preferably a or more, preferably a to 3a. With respect to the arrangement space of the fixing bolts 53, it is necessary to attach the end portions of the flexible rail joints 51 and 61 with a plurality of fixing bolts 53. This is because when the flexible rail joint is angled, the end of the flexible rail joint is prevented from rotating and the end joint is not displaced. When this deviation occurs, a step is formed at the joint, and smoothness is lost when guided along the step, and the stretching operation may not be smooth and may adversely affect.

  In addition, since it is desired to make the flexible rail joint easy to manufacture, when the length (a) in the longitudinal direction of the section where the slit 52 is arranged and the lengths of the attachment portions at both ends are substantially the same (≈a), The interval between the slit groups of the first and second flexible rail joints 51 and 61 is about 2a.

  In addition, when provided in the sheet | seat exit side of an extending | stretching part, a flexible rail joint will be in the state of a reverse direction with the bending state of said inlet side.

  FIG. 2 shows a conventional example in which six joints and seven flexible rail joints 51 (circles) are arranged, and six joints and seven first flexible rail joints 51 (circles, but the left end overlaps with circles ●. In comparison with the embodiment of the present invention in which the second flexible rail joint 61 (□) is arranged. FIG. 1 shows the lower guide rail omitted in FIG. 2, although the bending direction is opposite to that of the guide rail described above in FIG. Moreover, the broken line of FIG. 2 shows the rail arrangement | positioning in case the 2nd flexible rail joint 61 of the sheet | seat exit side of an extending part is not provided. From this figure, h, H ′, and H, which are factors that determine the draw ratio in the TD direction, are expressed by the following equations.

However, N is the number of joints, L is the length of one joint, and cos θ≈1.

  According to the present embodiment, by providing the first and second flexible rail joints in the vicinity of the bent portion of the guide rail, each joint bends at an angle of 6 ° or less in a stable state that is not unreasonable for the guide rail. As a whole, it is possible to create a large bending angle, and since the angle of one flexible rail joint is small and the level difference of the link running surface can be minimized, the extension can be performed smoothly and the high bending with a large bending angle can be achieved. The magnification can be changed without difficulty. In addition, by providing the 2nd flexible rail joint 61 also on the sheet | seat exit side of an extending | stretching part, although a draw ratio will become the maximum, when adding a drive mechanism, the direction shown with the broken line in the figure is more preferable.

  FIG. 3 shows an example for obtaining a larger stretch ratio by changing the angle of a joint other than the entrance portion in addition to the stretch of the embodiment of FIG. This example also has the effect of FIG. 2 and can further change the high draw ratio. Note that h, H ′, and H, which are factors that determine the draw ratio in the TD direction, are expressed by the following formulas (specific to six joints).

  In FIG. 4, the structure of the drive system of the flexible rail joint of a present Example is shown. As shown in FIG. 4A, the split movable bed 62 is pivotally coupled to the movable bed 55 so that both side surfaces of the beds of these pin coupling portions are flat springs (or laminated springs) 71. Is slidably attached and restrained. Similarly, the leaf springs (or laminated springs) 72 are slidably attached to the side surfaces of the pin coupling portions of the split movable bed 63 and the movable bed 56 that are pin-coupled.

  In FIG. 4B, reference numeral 73 denotes a drive cylinder (drive device) in which a drive shaft 74 is in contact with movable beds 55 and 56. By driving the drive cylinder 73 in the direction of the arrow 75, the movable beds 55 and 56 are simultaneously moved downward, and the driving force accompanying this movement is also applied to the split movable beds 55 and 56 via the plate springs 71 and 72. The divided movable beds 55 and 56 are both moved downward. By this movement, the flexible rail joints 51 and 61 fixed to each moving bed are bent with an angle of θ3 and θ4. Here, by adjusting the elastic strength of the leaf spring, the angles θ3 and θ4 can be set to be the same, and a large angle (θ3 + θ4) can be obtained without applying an excessive force to the guide rail. .

  As described above, according to this embodiment, it is possible to simultaneously drive a plurality of joints (flexible rail joints) of a plurality of guide rails with the same driving device. This simplifies the configuration and eliminates the need for adjusting the distance between the plurality of guide rails and adjusting the angle of the flexible rail joint when bending, and is easy to operate.

Applicable to all tenter type film stretching devices.

  DESCRIPTION OF SYMBOLS 1 ... Sheet | seat drawing machine, 2 ... Conveying space, 3 ... Link guide rail, 4, 5 ... Endless link device, 6, 7, 8 ... Sprocket, 9 ... Preheating area, 10 ... Drawing area, 11 ... Heat fixation 50, fixed bed, 51 ... first flexible rail joint, 52 ... slit, 53 ... fixed bolt, 55, 56 ... movable bed, 61 ... second flexible rail joint, 62, 63 ... split movable bed, 51 61, 205, 206: guide rails.

Claims (4)

An endless link device comprising a plurality of gripping devices for gripping end portions of a sheet of thermoplastic resin on both side ends of the sheet-like material is provided, and the endless link device includes a plurality of folding devices. It consists of an equal length link device, driven by sprockets on the inlet side and outlet side, and is fed from the sprockets on the inlet side and is guided by guide rails arranged in a parallel state and a divergent state in the traveling direction to stretch the sheet-like material In the sheet-like stretching machine configured to remove the sheet-like material after stretching and return to the inlet-side sprocket via the outlet-side sprocket,
A first flexible rail joint having a plurality of slits in the longitudinal direction of the rail side surface and a second flexible rail joint adjacent to the bent portion at the boundary between the parallel state and the divergent state of the guide guide rail are disposed. A sheet-like material drawing machine.   2. The sheet-like material drawing machine according to claim 1, wherein each of the flexible rail joints is disposed at a bent portion of an entrance / exit portion for drawing the sheet-like material.   The sheet-like material drawing machine according to claim 1 or 2, wherein when the length in the longitudinal direction of the section where the plurality of slits of the flexible rail joint is arranged is a, the interval between the flexible rail joints is a or more. Or a stretcher for sheet-like material, which is set to a to 3a.   The sheet-like material drawing machine according to any one of claims 1 to 3, wherein a common driving device for driving the first flexible rail joint and the second flexible rail joint to bend is provided. Sheet drawing machine.

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