JPH0615640A - Cutting method and its device of square shape of plastic sheet - Google Patents

Abstract

PURPOSE:To eliminate selection of a form by installing an oscillation sieve machine on the rear of the device, by a method wherein at the time of cutting of a plastic sheet into a square form, the cutting is performed by arranging a longitudinal cutting device and lateral cutting device in a horizontal direction. CONSTITUTION:A longitudinal cutting device 1 and lateral cutting device are arranged in a horizontal direction. The longitudinal cutting device 1 possesses two rolls referred to longitudinal cutter rolls 3. The cutter roll possesses a groove along the circumference on the surface of the roll. The two rolls are arranged so that a recessed part and protrusion are fitted in each other and turned in the opposite directions from each other so that the sheet is bitten by the two rolls at an upstream side. A plastic sheet 4 is put between the two rolls fitting in each other and cut along a longitudinal direction, that is, an advancing direction of the plastic sheet 4. The lateral cutting device 2 possesses a lateral cutter roll 5 possessing a lateral cutting rotary edge. The plastic sheet 4 is cut in a lateral direction, that is, in the direction meeting at right angles with the advancing direction of the plastic sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a rectangular shape of a plastic sheet and an apparatus used therefor.

[0002]

2. Description of the Related Art When a plastic sheet is molded, the plastic sheet is trimmed to a predetermined width to obtain a sheet with both ends cut off. Random width sheets and defective sheets generated during such trimming are collected and reused.The method is to perform remelting / extrusion of the sheet and pelletize it, and cut the sheet into a short shape to make a new raw material. There is a method to reuse after mixing with.

According to the conventional method for cutting a rectangular shape of a plastic sheet, the plastic sheet is supplied from the upper side to the lower side, and the plastic sheet is cut into a rectangular shape by a vertical cutting device and a horizontal cutting device respectively arranged in the vertical direction. Be cut off.

However, the conventional method using the rectangular shape cutting device (Torai Iron Works Co., Ltd., trade name: square-cutting pelletizer) of Japanese Patent Publication No. 46-29707 has the following problems. The plastic sheets are fed vertically, i.e. from top to bottom. The fed sheet is first cut by a vertical cutting device into strips having a width of 1 to 10 mm in the width direction with respect to the traveling direction of the sheet. The wavy undulations at the edge portions of the sheet are locally cut when being cut in the vertical direction, so that they are not fed into a continuous band but are directly supplied to the transverse cutting device. Also, when the sheet is meandered and fed, the sheet is likewise locally cut, so that the sheet is not fed into a strip shape but is fed to the crossing device as it is. The continuous strip obtained by vertical cutting with a vertical cutting device is cut into a desired length by a fixed blade and a rotary blade. A defective cut product (also called a short product) that does not form a continuous strip is discharged to the outside of the device without being cut into a square shape or a short shape by the cross cutting device.

Therefore, according to the conventional method, a vibrating screener or the like is often used to remove and sort the short products, and troubles such as clogging due to the short products sticking into the wire mesh frequently occur. Further, when a short product is pneumatically transported, troubles such as clogging and bridges occur in the transportation piping and the transportation device hopper, and the production is interrupted.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for cutting a rectangular shape of a plastic sheet and a device used for the method, which solves the above problems.

[0007]

As a result of intensive studies for solving the above-mentioned problems, the present inventor has surprisingly found that the arrangement of the vertical cutting device and the horizontal cutting device is changed from the vertical direction to the horizontal direction. The inventors have found that the problems can be solved and completed the present invention.

That is, the present invention relates to a method for cutting a rectangular shape of a plastic sheet, and further to an apparatus used in the method.

The present invention will be described in detail below. FIG. 1 is a diagram showing an embodiment of a cutting device used in the present invention.

In the present invention, the vertical cutting device 1 and the horizontal cutting device 2 are arranged in the horizontal direction. The vertical cutting device 1 has two rolls called vertical cutting cutter rolls 3. The cutter roll has grooves along the circumference of the roll surface.
The two rolls are arranged so that the concave and convex parts fit together,
The sheet is rotated in the opposite direction so as to mesh the sheet on the upstream side. The plastic sheet 4 is sandwiched between two rolls that fit together, and is cut in the vertical direction, that is, along the traveling direction of the plastic sheet 4. The transverse cutting device 2 has a transverse cutter roll 5 having a transverse rotary blade. The plastic sheet 4 is cut in the lateral direction, that is, in the direction perpendicular to the traveling direction of the plastic sheet by the meshing of the rotary blade and the fixed blade of the roll.

In the present invention, the plastic sheet 4 is fed horizontally. Here, the term "horizontal direction" does not necessarily mean that the position is perfectly horizontal, but a position shift that allows the position to be maintained substantially horizontal is allowed. The material of the sheet is not particularly limited, but may be a polypropylene sheet, a polyethylene sheet, or a polyvinyl chloride sheet. The thickness of the sheet is not particularly limited, but may be 0.5 to 15 mm.
Most of the cut sheets are undulated at least on one end side, but may be trimmed and commercialized sheets.

The sheet is first cut by the vertical cutting device 1.
The sheet is cut into strips in the width direction with respect to the traveling direction of the sheet. The sheet width is not particularly limited, but is 1
It is about 10 millimeters wide. The sheet width is determined by the groove size of the vertical cutter roll 3.

The vertical cutting device 1 has a defective cutting product 6,
When the so-called short product is provided with the discharge port 6 ', the defective cutting product is continuously discharged to the outside of the apparatus.
Therefore, only the strips that are continuously connected are supplied to the crossing device 2.

A rectangular pellet is obtained by cutting the band-shaped material in the transverse cutting device 2. The shape of the cut product is not particularly limited, but a square product and a rectangular product are preferred.

The crossing device is provided with a discharge port 7'for discharging a rectangular pellet which is a good product 7.
Therefore, the square pellets are continuously discharged out of the apparatus.

A comb or a brush 8 may be provided between the vertical cutting device 1 and the horizontal cutting device 2 as a guide for the band-shaped material. By using the guide together, meandering of the plastic sheet is prevented and defective cutting 6 is prevented. Further, the tip end of the vertically cut plastic sheet is liable to curl vertically in two directions downstream of the vertical cutter roll 3. A movable guide 10 and a fixed guide 11 (not shown) are provided in order to suppress the curling and guide the leading end of the curled plastic sheet to the pinch roll 9. The movable guide 10 has a structure that opens immediately after passing the sheet in order to drop the defective cutting product 6 downward by opening the guide.
Specifically, the movable guide 10 is opened by detecting the tip of the plastic sheet after passing through the pinch roll 9. Opening this guide causes defective cutting 6
Falls down.

A pinch roll 9 is also used in order to smooth the sheet feeding in the horizontal direction. A sheet presser 12 is provided between the pinch roll 9 and the crossing device 2. Immediately after the end portion of the plastic sheet is fed downstream from the pinch roll 9, the drive source is lost and the vertically cut sheet stops moving. Due to the sheet re-supplied, the sheet stopped immediately after the pinch roll 9 is pushed out in the direction of the transverse cutting rotary blade. The pushed sheet is cut by the rotating transverse cutting rotary blade 13 and the fixed blade 14 to be shortened. When the remaining sheet becomes several tens of mm, the impact of the cutting by the rotary blade raises the sheet and defective transverse cutting occurs. A sheet presser 12 is provided to prevent such rising of the sheet.

[0018]

EFFECTS OF THE INVENTION According to the present invention, since it is possible to produce a rectangular pellet without mixing of defective cutting products, a vibrating screener or the like is installed after the apparatus as in the conventional method to select the shape. You don't have to. Further, it is possible to prevent the occurrence of troubles such as clogging and bridges in the transportation piping and the transportation device hopper during pneumatic transportation of the rectangular pellets, so that the rectangular pellets can be continuously produced. Further, in the present invention, since the device such as the vibrating screener is not necessary, energy can be saved and the space for installing the device can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of the apparatus of the present invention.

FIG. 2 is an example of a plastic sheet or the like.

FIG. 3 is an example of a conventional device.

[Explanation of symbols]

 1 Vertical cutting device 2 Horizontal cutting device 3 Vertical cutting cutter roll 4 Plastic sheet 5 Horizontal cutting cutter roll 6 Defective cutting product 6'Ejecting port for discharging defective cutting product 7 Good product 7'Ejecting device for ejecting good product 8 comb or Brush 9 Pinch roll 10 Movable guide 12 Sheet retainer 13 Rotating blade 14 Fixed blade

Claims (6)

[Claims] 1. A method of cutting a rectangular shape of a plastic sheet, which comprises arranging a vertical cutting device and a horizontal cutting device in a horizontal direction when cutting the plastic sheet into a rectangular shape. 2. A rectangular sheet cutting device for a plastic sheet, which is used in the method of claim 1. 3. The rectangular sheet cutting device for a plastic sheet according to claim 2, wherein the vertical cutting device has a discharge port for defective cutting products. 4. The rectangular cutting device for a plastic sheet according to claim 2, further comprising a movable guide and a fixed guide as guides for the plastic sheet. 5. The rectangular-shaped cutting device for a plastic sheet according to claim 2, further comprising a pinch roll on the downstream side of the fixed guide. 6. The device for cutting a rectangular shape of a plastic sheet according to claim 2, further comprising a sheet presser between the pinch roll and the cross cutting device.