JPS62152723A - Continuously stretching device - Google Patents

Abstract

PURPOSE:To continuously form a heat shrinkable sheet out of a preformed piece on continuous form by a structure wherein pairs of chucking blocks, each of which grasps one of both side parts of a softened preformed piece so as to pull the piece toward both sides of it, are provided so as to be freely accessible and separable. CONSTITUTION:When the tip of a preformed piece A, which has been brought into softened state by heating in advance, is fed nearly horizontally from the rear of a stretching part 4 between both caterpillar treads 1 and 1, first, clamps 9, which approach the rear position of the stretching part 4, close so as to grasp both side edge parts of the preformed piece A between both pairs of chucking blocks 11 and 12. Secondly, when the clamps 9... in clamped state approach the stretching part 4, the interval W between the treads facing each other of both revolving courses gradually widens and consequently the preformed piece A grasped with the clamps is stretched widthwise while being carried in the longitudinal direction. When the clamps 9... approach the parallel part 5, a cooling mechanism 8 cools the preformed piece A just after being stretched from above and below. Because, by said cooling action, the preformed piece A after the stretching is hardened under the state that both side edge parts of the piece A are held by the clamps, the waviness and the like, which tend to develop in a sheet after the clamping is released, is hard to occur.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a continuous stretching device that stretches a strip-shaped material to be stretched in its width direction while continuously conveying it in its longitudinal direction.

"Prior Art" When manufacturing heat-shrinkable articles, such as heat-shrinkable sheets for protecting cable connections, a preformed product (material to be stretched) is formed into a predetermined shape using a mold. The work of stretching is carried out.

Conventionally, a stretching device used for such stretching operations includes, for example, a pair of gripping tools disposed opposite to each other, and a movement mechanism that relatively moves these gripping tools in the opposing directions, and a stretching device that has been heated in advance. The softened preform is stretched by grasping both sides of the preform with a gripping tool and pulling it to both sides. In other words, in the case of heat-shrinkable sheets, short preforms of several heat-shrinkable sheets are stretched one by one.

"Problems to be Solved by the Invention" By the way, when manufacturing heat-shrinkable articles with simple shapes such as the heat-shrinkable sheets mentioned above, extrusion molding is performed and long preformed products (heat-shrinkable It is desirable to improve productivity by continuously molding a preformed product in the form of a large number of shrinkable sheets. However, with the conventional stretching equipment described above, it is impossible to stretch a long preform in the width direction without cutting it into pieces, and therefore, all manufacturing processes after the stretching process are discontinuous. Because it requires a lot of work, such a stretching device is a bottleneck in efficiently manufacturing heat-shrinkable sheets.

The present invention has been made in view of the above circumstances, and its purpose is to provide a continuous stretching device that can stretch a strip-shaped material to be stretched in the width direction while continuously conveying the material in the longitudinal direction. It's about doing.

"Means for Solving the Problem" In order to achieve the above object, the first invention of the present application uses a pair of endless tracks formed by connecting a large number of gripping tools in a loop shape, and the pair of endless tracks are are arranged so that a part of their circumferential path faces each other, and an extending portion is provided in the opposing portion of the circumferential path so that the opposing interval gradually decreases in the circumferential direction of the endless track, and each gripping tool is arranged in pairs. The chucking blocks are connected so as to be able to approach and separate and are biased in the direction of separation, and furthermore, a guide member for pressing the chucking blocks in the direction of approach is disposed on the extending portion.

Further, the second invention of the present application is characterized in that, in addition to the structure of the first invention, the circumferential path is configured to be movable in the opposite direction, and an interval adjustment mechanism for moving the circumferential path is provided.

Furthermore, in addition to the structure of the first invention, the third invention of the present application provides a parallel part continuous to the front of the extending part and having a constant facing interval in the opposite part of the circumferential path, and also provides a guide member on this parallel part. It is characterized in that it is provided with a cooling mechanism that cools the space between the parallel parts.

"Operation" According to the first to third inventions, when the endless track is rotated, each gripper is pressed by the guide member near the rear end of the extending portion and closed (bringing both chucking blocks closer together). ), it escapes the pressure of the guide member and opens near the front end of the extending portion (separates both chucking blocks). Therefore, by feeding the tip of the softened belt-shaped material to be stretched between the two endless tracks, each gripping tool of both endless tracks sequentially grips both side line parts of the material to be stretched to both chucking blocks near the rear end of the stretching part. It is held in between and conveyed in the circumferential direction. In the stretching section, the opposing distance between the circumferential paths gradually widens, so the gripper conveys the material to be stretched and stretches it in the width direction, and then releases its grip on the material near the front end of the stretching section. Then, it circulates again near the rear end of the stretching section.

Further, according to the second invention, by operating the distance adjustment mechanism, the distance between the opposing portions, that is, the extending portion and the circumferential paths before and after the extending portion is changed.

Further, according to the third aspect of the invention, the cooling mechanism cools the material to be stretched immediately after being stretched and still being held by the gripping tool.

"Example" Embodiments of the present invention will be described below based on the drawings.

FIG. 1 schematically shows the overall structure of an embodiment of the present invention, and reference numeral 1-1 in the figure indicates a pair of endless tracks. These endless tracks are made to rotate in opposite directions along respective loop paths (paths formed by the chain guide 2, sprocket wheel 3, etc.) laid out in a loop in a horizontal plane. , with parts of both circuit routes facing each other on the left and right.

At the opposing portions of both circumferential routes, there is an extension portion 4 whose opposing interval W gradually increases toward the front in the running direction of the endless track l (the circumferential direction in the opposing portion, that is, the direction of arrow A in FIG. 1).
A parallel part 5 which is continuous in front of the extending part 4 and whose opposing distance W is constant is formed. Further, a guide member 6 for pressing a chucking block, which will be described later, is disposed on the circumferential path from the rear position of the extending portion 4 to the parallel portion 5. For example, as shown in FIG. 2, the guide member 6 is inclined so that the height of the rear side of the extending part 4 is gradually lowered toward the front, and the front part of the guide member 6 from the extending part 4 to the parallel part 5 is inclined. It is a rail whose height is constant. These guide members 6 and the circumferential path (that is, the chain guide 2 and sprocket wheel 3, etc.) are configured to move and hang in opposite directions (in the direction of the arrow in FIG. 1), and by moving these, A spacing adjustment mechanism 7 for adjusting the facing spacing W is connected to both the circumferential paths. Furthermore, a cooling mechanism 8 (see FIG. 2) is disposed above and below the parallel portions 5 to spray a refrigerant (for example, cold air, cooling gas, etc.) into the space between the parallel portions 5.

On the other hand, the endless track is formed by connecting a large number of gripping tools 9 in a loop shape with a chain 10, and each gripping tool 9 is connected to a pair of upper and lower chucking blocks 1 as shown in FIG.
1.12. Lower chucking block 1
1 is fixed to the chain 10, and the upper chucking block 12 connects the rod 1 to the lower chucking block 11.
3 so as to be slidable (approaching and separating) in the vertical direction, and is urged upward (in the separating direction) by a spring 14. Moreover, the upper chucking block 12 is provided with an engagement groove 15 along the extending direction of the endless track 1 on its lower surface.

Next, a method of operating the apparatus and its operation when stretching a heat-shrinkable sheet preform (indicated by reference numeral A in the figure) using the continuous stretching apparatus configured as described above will be described. However, the preformed product A is, for example, a continuous extrusion-molded band-shaped plastic molded product, and its both side edges have protrusions a" projecting from one side as shown by the chain lines in Figure 3.
Assume that a is formed.

First, operate the spacing adjustment mechanism 7 and set the chain guide 2.
moving the sprocket wheel 3 etc. in the opposing direction;
The facing interval W between the circular routes is set to a desired interval. In other words, the opposing distance W near the rear end of the stretched portion 4 is adjusted to the width dimension of the preform A, and the opposing distance W in the parallel portion 5 is adjusted to the width dimension after stretching (width dimension determined by the desired stretching ratio). . Then, while operating the cooling mechanism 8, the sprocket wheel 3 is driven to continuously revolve around the endless track 1-1. At this time, since the upper chucking block 12 is urged upward by the spring 14, each gripper 9 moves along the circumferential path with the chucking blocks 11 and 12 separated from each other as shown in the right end of FIG. Trying to walk along. However, when reaching the opposing portion of the circumferential path, the guide member 6 presses the upper surface of the upper chucking block 12 and gradually guides it downward (in the approach direction), so that each gripper 9 is placed behind the extending portion. By the time it reaches the end, it is completely closed as shown in Figure 3 (both chucking blocks 11 and 12 are close together), and the parallel part 5
After passing through, the upper chucking block 12 escapes the pressure of the guide member 6 and rises, thereby performing an operation of opening again (separating both chucking blocks 11 and 12).

In such an operating state, the preformed product A, which has been heated and softened in advance, is held almost horizontally and its tip is placed in the stretching section 4.
When the preform A is fed between the two endless tracks 1-1 from behind, the gripper 9, which has reached the rear position of the extension part, closes and grips both side edges of the preform A between the two chucking blocks 11 and 12. . At this time, the upper chucking block 1
The second engagement groove 15 engages with the protrusion a"a of the preform A as shown by the chain line in FIG. At the same time, the subsequent gripping tools 9... grip the preformed product A one after another and transport it together.Next, these gripping tools 9.
When ... approaches the extension part 4, the opposing distance W between both circumferential paths gradually widens, so the gripping tools 9 of both endless tracks 1 gradually widen the mutual distance, and therefore the preform being gripped While conveying the product A in its longitudinal direction (direction A in FIG. 1), it is stretched in the width direction (direction toward the opening in FIG. 1). At this time, a reaction force is generated in the preform A against the tension during stretching, and this reaction force tries to remove the both side edges from the gripping tool 9.
The engagement between the engagement groove 15 and the protrusion a prevents this. Subsequently, when the gripping tool 9... approaches the parallel part 5,
A cooling mechanism 8 cools the preform A immediately after being stretched from above and below. Due to this cooling action, the preformed product A after stretching is hardened while its both side edges are gripped (in a state where it is taut due to tension), so that the waving phenomenon of the sheet that tends to occur after the grip is released is less likely to occur. After that, the gripping tools 9 reach the rear end of the parallel part 5 and both chucking blocks 11
．． 12 is separated, and the stretched preform A is released and circulated to the rear position of the stretching section 4 again. Therefore, the released preform A is either continuously conveyed as it is to the next process, or wound up on a bobbin or the like.

On the other hand, FIGS. 4 to 6 show other embodiments of the present invention. In these figures, the endless tracks 16, 16 are made to orbit in the same direction along their respective orbiting routes that draw loops in the vertical plane, and parts of both orbiting routes are opposite to each other on the left and right. It is arranged like this. That is, in this case, the endless track 16 is formed by connecting a large number of gripping tools 9 with a so-called curved chain 17.

Since such a stretching device has the circular path of the endless track 16 in a vertical plane, it occupies a smaller area than the stretching device of the above embodiment, and is suitable for installation in a limited space.

In the above embodiment, the two circumferential paths are opposed to each other laterally, but they may be opposed to each other in any direction, such as vertically or diagonally. Further, in the embodiment, the upper chucking block 12 is urged upward by the spring 14, but for example, the chucking blocks 11 and 12 may be arranged upside down and the chucking block 12 is urged downward by gravity. The chucking block 12 may be pushed upward by a guide member. Furthermore, a belt may be used instead of the chain IO or curved chain 17, and instead of connecting both chucking blocks 11, 12 via the rod 13, they may be hinged.

"Effects of the Invention" As explained above, according to the first invention of the present application, a pair of endless tracks formed by connecting a large number of gripping tools in a loop shape is prepared, and a part of the orbiting path of these endless tracks is The chucking blocks are arranged so as to face each other, and extending portions are provided in opposing parts of the circumferential path so that the opposing interval gradually decreases in the circumferential direction of the endless track, and each gripper can freely approach and separate a pair of chucking blocks. Since the chucking block is connected and urged in the separating direction, and the guide member that presses the chucking block in the approaching direction is disposed on the extending portion, the following effects can be obtained.

When the endless track is rotated, each gripper is pressed by the guide member near the rear end of the extending portion to close, and opens near the front end of the extending portion while escaping the oppression of the guide member. Therefore, when the leading end of the strip-shaped material to be stretched is fed between the two endless tracks, the gripping tools of the two endless tracks sequentially grip both side edges of the material to be stretched near the rear end of the stretching part, and the material is conveyed in the circumferential direction. In the stretching section, the material to be stretched is conveyed and stretched in the width direction, and then the material to be stretched is released near the front end of the stretching section and circulated again near the rear end of the stretching section. That is, it is possible to automatically stretch the strip-shaped material to be stretched in the width direction while continuously conveying it in the longitudinal direction, and it is possible to significantly improve the productivity of heat-shrinkable articles.

Further, according to the second invention of the present application, in addition to the structure of the first invention, the circumferential path is configured to be movable in the opposite direction, and an interval adjustment mechanism for moving the circumferential path is provided, so that in addition to the above-mentioned effects, The following effects can be obtained.

By activating the spacing adjustment mechanism and moving the circumferential path in the opposing directions, the opposing spacing near the rear end of the extending portion can be freely adjusted to match the width dimensions of various preforms, and A desired stretching ratio can be set by freely adjusting the opposing distance in the parallel portions.

Furthermore, according to the third invention of the present application, in addition to the structure of the first invention, a parallel part with a constant facing interval that continues forward of the extending part is provided in the opposing part of the circumferential path, and on this parallel part also Since the guide member is provided and the cooling mechanism for cooling the space between the parallel parts is provided, the following effects can be obtained in addition to the effects of the first invention.

The cooling mechanism cools the material to be stretched, which has just been stretched and is still being held by the gripping tool. Therefore, since the preformed product after stretching is cured in a taut state due to the tension during stretching, the waving phenomenon of the sheet that tends to occur after releasing the grip is less likely to occur. In other words, a heat-shrinkable article of excellent quality can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view showing one embodiment of the present invention, FIG. 2 is a view taken along the line ■-■ in FIG.
4 is a schematic plan view showing another embodiment of the present invention, FIG. 5 is a view taken along the ■-V line in FIG. 4, and FIG. 6 is a view taken along the Vl-Vl line in FIG. 5. It is an arrow view. 1.16... Endless track, 4... Extension part, 5... Parallel part, 6... Guide member,
7... Spacing adjustment mechanism, 8... Cooling mechanism, 9... Gripping tool, 10... Chain,
11.12...Chucking block, 14.
...Spring, 15...Engagement groove, 17...
...Curved chain, A...Preformed product,
a... Projection, W... Opposing interval. 6th ryJ

Claims (1)

[Scope of Claims] 1) A pair of endless tracks (1) are arranged so that part of their circular paths are opposite to each other, and the opposing interval (W) is in the circumferential direction of the endless tracks in the opposing parts of the circular paths. The endless track is formed by connecting a large number of gripping tools (9) in a loop shape, and each gripping tool has a pair of chucking blocks (11, 12). They are connected so that they can approach and separate, and are biased in the direction of separation, and further,
A continuous stretching apparatus characterized in that a guide member (6) for pressing the chucking block in the approaching direction is disposed on the stretching section. 2) A pair of endless tracks (1) are arranged so that parts of their circuit paths are opposite to each other, and the opposing distance (W) in the opposing portions of the circuit paths gradually increases in the direction of rotation of the endless tracks. (4), and further includes an interval adjustment mechanism (7) for configuring the circumferential path to be movable in the opposite direction thereof and for moving the circumferential path, and the endless track holds a large number of gripping tools (9) in a loop shape. Each gripping tool has a pair of chucking blocks (11, 12) connected to each other so as to be able to move toward and away from each other and biased in the direction of separation. A continuous stretching device characterized in that a guide member (6) is provided for pressing the material in the approaching direction. 3) A pair of endless tracks (1) are arranged so that parts of their orbiting routes are opposite to each other, and on opposing parts of the orbiting routes,
An extending part (4) whose facing interval (W) gradually widens toward the front in the circumferential direction of the endless track, and a parallel part (5) which continues in front of this extended part and has a constant facing interval, are provided, and the endless track consists of a number of gripping tools (9) connected in a loop, each gripping tool having a pair of chucking blocks (11, 12).
The chucking block is connected so as to be able to move toward and away from each other and is biased in the direction of separation, and furthermore, a guide member (6) for pressing the chucking block in the direction of approach is disposed on the circumferential path from the extending part to the parallel part. Moreover, a continuous stretching apparatus characterized in that a cooling mechanism (8) for cooling the space between the parallel parts is provided.