JP2001260255A - Method of opening cut edges of superposed sheets - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of opening desired parts of cut edge of two resin sheets partially, smoothly and without fail. SOLUTION: Parts to be opened of the cut edges of the two resin sheets put on each other are scrubbed lightly by a fixed abrasive such as sandpaper or rubstone, or a file and then air is jetted to the cut edge from an air nozzle to open it. In the pre-process of the scrubbing, the part to be opened of the cut edge cut by a shear cutting edge operating in the direction perpendicular to the surface of the sheets is cut off by a sharp cutting edge operating in the direction parallel to the surface of the sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for partially opening a desired portion of a cut edge of two superposed resin sheets, particularly a thermoplastic synthetic resin sheet.
For example, the tip of a pipe serving as a bag mouth of a bag formed of the two sheets is inserted into the opening.

[0002]

2. Description of the Related Art Bags formed by heat-sealing or joining the periphery of two superposed resin sheets are widely used as containers for various liquids. In this case, how to provide the mouth of the bag varies depending on the use of the liquid as the contents, but in the case of a bag for chemicals for infusion, for example, a thin pipe is attached to one place around the joined portion. It is fixed as a bag mouth. This pipe is fixed with its base end inserted between two resin sheets forming a bag.

[0003] A bag mouth pipe is attached to a bag having the above-described structure in the following manner. Two resin sheets drawn from the roll are superimposed and fed by a roller or a conveyor, and cut with one side of the two superimposed. The air nozzle is opposed to a portion of the cutting edge where the pipe is to be inserted, and the vacuum pipe is arranged so as to vertically suck the sheet of the portion facing the nozzle. Then, air is blown out from the air nozzle toward the joint of the two sheets, and at the same time, the two sheets are sucked up and down by a vacuum pipe to form an opening between the two sheets. Then, a pipe serving as a bag opening is inserted into the opening, and the periphery of the sheet including the inserted portion of the pipe is joined by, for example, heat welding to obtain a desired bag.

[0004]

In order to obtain a bag of a desired size, it is necessary to cut the periphery of the two stacked sheets into a predetermined size. This cutting operation is also necessary to obtain a bag with a good finished shape in which the upper and lower sheets are properly aligned. In the cutting of the sheet, the blade is operated in a direction orthogonal to the sheet surface, and the sheet is cut by a shearing action similar to scissors.

[0005] It is after the cutting operation to open a location around the two sheets to insert the bag opening pipe. However, resin sheets, especially thermoplastic synthetic resin sheets, when cut with a blade, are softened or melted by local processing heat, so that at the cutting edge, the two sheets do not lightly engage. It is in a welded state. For this reason, even if air is blown to the cutting edge of the portion where the pipe is to be inserted, the two sheets do not separate and an opening for inserting the pipe cannot be formed.

[0006] If two sheets are sucked by vacuum from both sides over a wide range, it is possible to easily open the two sheets. However, in order to insert a thin pipe into one surrounding area, two sheets are required. A large opening of two sheets not only wastes equipment, power consumption and processes, but also increases the amount of dirt entering between the two sheets inside the bag. It is not preferable as a method used in a manufacturing process of a bag for storing foods and the like.

An object of the present invention is to provide a technical means for smoothly opening a part of a cutting edge of two resin sheets cut in an overlapped state.

[0008]

According to the method of the present invention, 2
After lightly rubbing a portion of the cut resin sheet that is to be opened with sandpaper, a fixed abrasive such as a grindstone or a file, the air is ejected from the air nozzle toward the cut edge to open. This is the first feature. Further, in the method of the present invention, the portion to be opened of the cutting edge cut by the shearing cutting blade operating in the direction perpendicular to the surface of the sheet, prior to rubbing with the fixed abrasive or the file, The second feature is that the cutting is performed with a sharp cutting blade operating in a direction parallel to the plane.

That is, in the method for opening a cut edge of a polymerized sheet according to claim 1 of the present application, a method for opening a cut edge of a resin sheet cut by overlapping two sheets by separating a part of the cut edge is provided. After sandwiching and fixing the two sheets at a position close to the portion 14 to be opened, the portion 14 of the cutting edge is lightly rubbed with sandpaper, a grindstone, a file, and the like.
The method is characterized in that air is jetted from an air nozzle toward the overlapping surface of the sheet in the portion.

When this method is used in the manufacturing process of a bag for chemicals or the like, the sheet on both sides of the portion opened by the above method is sucked by a vacuum pipe to maintain the open state, and the opening forms a bag opening. After inserting the end of the pipe, the periphery of the two sheets, including the inserted end of the pipe, is joined by means such as heat welding to obtain a desired bag.

The rubbing of the cutting edge with a fixed abrasive or a file needs to be performed within a force and at a speed at which the edge of the sheet is not softened or melted by frictional heat. Rubbing with a speed of lightly rubbing is appropriate.

A method according to a second aspect of the present invention is a sharp cutting blade for moving a portion to be opened of a cutting edge in a sheet surface direction before rubbing with a fixed abrasive or a file in the method of the first aspect. After cutting in step 5, the cut portion is rubbed with a fixed abrasive such as sandpaper or a grindstone or a file, and then air is blown between two sheets of the portion 14 from an air nozzle.

[0013] The rubbing by the fixed abrasive grains or the file is not so strong as to generate chips, but when extremely disturbing the invasion of dirt into the bag, the rubbing is performed when the rubbing is performed. It is even better if a suction pipe is advanced in the vicinity of the pipe to remove any generated powder.

Examples of the sharp cutting blade 5 include a commonly used razor and a cutting blade of a cutter knife. The movement of the cutting blade relative to the sheet is generally a pure movement in the plane direction that does not involve movement in the direction perpendicular to the plane of the sheet. However, movement in the direction perpendicular to the plane depends on the material of the sheet and the shape of the cutting edge. You can also. In this case, the movement of the cutting edge in the direction perpendicular to the plane gives the same effect to the sheet as if the cutting edge angle of the cutting blade was made sharper.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the drawings. Two belt-shaped thermoplastic sheets 2 wound on the roller 1 are stacked and brought into close contact with each other, conveyed to a cutting position by a nip roller or a conveyor belt, and lowered from above with a fixed blade arranged to receive the lower surface of the sheet. The edge is cut by shearing action with the moving blade. At this time, the tongue piece 3 is formed on the cutting edge by providing unevenness on the fixed blade and the movable blade.

Next, the sheet is conveyed to the opening position, and a slightly deeper side of the portion where the tongue piece 3 is provided is sandwiched by the upper and lower pressers 4 from both sides. The end face of the presser foot 4 (the surface in contact with the sheet) has a shape in which a relief is provided so as not to press the root of the tongue piece 3. By clamping the two sheets with the presser foot 4, the sheets are fixed and also the air or the like is flowed between the two sheets unnecessarily to prevent the inside of the bag from being polluted.

Next, the tongue piece 3 is cut off by moving the vertical cutting blade 5 with the cutting edge in a direction parallel to the cutting edge in the direction of arrow 6 along the cutting edge. After cutting off the tongue piece 3 with the cutting blade 5, the cutting edge portion 14 cut with the cutting blade 5 is
Rub lightly with a sandpaper with a roughness of about 100 wound around. This rubbing is performed by rotation of the roller 7 and movement of the roller 7 in a direction parallel to the cutting edge. As described above, the rotation of the roller 7 is set to a relatively low rotation so that a large amount of frictional heat is not generated in the sliding portion.

Next, air is blown from the air nozzle 8 toward the cutting edge of the portion where the tongue piece 3 has been cut off, so as to blow air between the two sheets. A vacuum pipe 9 is opened in the relief portion of the presser foot 4 so as to be slightly separated from the sheet 2. When air is jetted from the air nozzle 8, the sheet at the escape portion of the presser foot 4 is separated and opened, and each is sucked into the opening of the vacuum pipe 9, and the partially open state is maintained.

Then, the cutting blade 5 and the air nozzle 8 are retracted, the pipe 10 serving as a bag opening is inserted into the opening 11, and then the holding of the sheet at the opening portion by the vacuum pipe 9 is released. send.

In the heat welding step, the periphery of the two sheets, including the portion into which the pipe 10 is inserted, is heat-welded by high-frequency heating, and only the pipe 10 serving as a bag opening is sealed with the periphery communicating with the outside. A bag 12 is formed.

In the above embodiment, the tongue piece 3 is provided in order to facilitate the cutting operation by the cutting blade 5 at the portion where the cutting edge is to be opened. Without providing such a tongue piece, it is possible to partially remove the cutting edge by causing the cutting blade 5 to move partially around the cutting edge 13. If the material of the sheet has a low degree of softening or melting by shear cutting, only partial rubbing of the cutting edge by the fixed abrasive grains is performed without removing the partial cutting edge by the cutting blade 5. It is also possible to open a part of the cutting edge smoothly.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a sheet shearing cutting process of an embodiment.

FIG. 2 is an explanatory view showing a cutting edge cut by a cutting blade and a rubbing step by abrasive grains in the embodiment.

FIG. 3 is an explanatory view showing a sheet opening process by an air nozzle according to the embodiment.

FIG. 4 is an explanatory view showing a step of inserting a pipe after opening.

FIG. 5 is a perspective view of a completed bag.

[Explanation of symbols]

 5 Cutting edge 14 Cutting edge

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E075 AA28 BA42 CA02 DA04 DB14 DD13 DD44 DD46 DE03 DE04 GA02 GA04

Claims (2)

[Claims] In a method of opening a part of a cutting edge of a resin sheet cut in a double-layered manner, two sheets are located at a position close to a portion (14) of the cutting edge to be opened. After fixing the portion (14) of the cutting edge by rubbing with a fixed abrasive or a file, air is blown from an air nozzle between two sheets of the portion (14),
How to open the cut edge of the polymer sheet. 2. A method of opening a part of a cutting edge of a resin sheet cut by stacking two sheets at a position close to a portion (14) of the cutting edge to be opened. After cutting the relevant portion (14) of the cutting edge with a sharp cutting blade (5) operating in the surface direction of the sheet, the cut portion is rubbed with a fixed abrasive or a file, and then the relevant portion is cut.
(14) The method for opening a cut edge of a superposed sheet, wherein air is blown from an air nozzle between the two sheets.