JPH0136596Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Field of Application] The present invention relates to an improvement in an apparatus for heat welding a film to form a handle and a bottom when a synthetic resin tube is continuously processed to manufacture a carrier bag. [Background technology and its problems] Normally, synthetic resin tube band members are manufactured from raw resin materials by the inflation method. It is manufactured as a rolled material. When manufacturing synthetic resin bags, the original fabric is attached to a device, and the bag with a handle is continuously manufactured while supplying a belt-like member from the original fabric. . In such a case, it is inappropriate to directly transfer the strip-like member supplied from the original fabric to the heat-welding mechanism for forming the handle portion, and a dancer mechanism or the like is used as a mechanism that has a buffering effect against fluctuations in the supply state of the strip-like member. A back tension applying mechanism is provided between the original fabric and a heat welding mechanism or the like. As shown in FIG. 1, a gazette tube 1 as a band-like member is supplied from a raw material (not shown) and consists of a movable roller group 2 consisting of a plurality of movable rollers whose rotating shafts are connected to each other, and a plurality of fixed rollers. A heat welding bar 5A that can move forward and backward after being wound around a dancer mechanism 4 having a fixed roller group 3,
It is transferred to a heat welding mechanism 5 made of a hard plate 5B fixed so as to be inserted into the folded part of the gazette tube 1. When a carrying bag is formed from the gazette tube 1, the heat welding mechanism 5 heat-welds a portion corresponding to the handle and/or bottom of the carrying bag. The conveyance of the gazette tube 1 is carried out by a feed roll 6 which is provided on the gazette tube feeding side of the heat welding mechanism 5 and is configured to sandwich and feed out the gazette tube 1 on its outer peripheral surface.
It is done by. Further, the heated and welded gazette tube 1 sent out from the feed roll 6 is appropriately sealed and cut by a cutter blade 7 with a heat seal bar to form individual carrier bags. However, according to such a conventional heat welding device, the gazette tube 1 as a strip member is
A tension in the longitudinal direction is always exerted on the gazette tube 1 by the dancer mechanism 4 as a buck tension applying mechanism, and even when heat welding is performed by the heat welding mechanism 5, tension in the longitudinal direction is still exerted on the gazette tube 1. . Therefore, the heat welded part heated by the heat welding mechanism 5 and turned into a molten state is extremely softened compared to other parts.
This heat-welded part, especially the welded seam, is stretched thin, resulting in a disadvantage that the strength of the heat-welded part is significantly reduced. Therefore, when a carry bag with a handle is manufactured by heat welding the gazette tube 1 using a conventional heat welding device, there is a drawback that the strength of the handle is significantly reduced. [Purpose of the invention] The purpose of the invention is to prevent the heat welding part, especially the welding edge, from being stretched thin due to tension, even if it is equipped with a back tension application mechanism necessary for buffering fluctuations in the supply state of the strip member. Therefore, it is an object of the present invention to provide a heat welding device for the handle and/or bottom of a carrier bag, which can increase the strength of the carrier bag. [Means and effects for solving the problem] In order to achieve this object, the heat welding apparatus according to the present invention includes a back tension applying mechanism that applies tension in the longitudinal direction to the supplied strip member, and a back tension applying mechanism that applies tension in the longitudinal direction to the supplied strip member. A heat welding mechanism is provided on the feeding side of the belt-like member from the tension applying mechanism and heat-welds a portion corresponding to the handle and/or bottom of a carrier bag formed from the belt-like member; In the heat welding device for the handle and/or bottom of a carrier bag, which is configured to include a feed roll provided on the feed side of the member, between the back tension application mechanism and the heat welding mechanism,
The belt-like member is loosened before heat-welding by the heat-welding mechanism, and rotates in conjunction with the feed roll, and the belt-like member is heat-welded by a greater amount than the amount of feed of the belt-like member by the feed roll. A tension adjusting roll is provided which increases the amount of feed of the belt-shaped member by the length of the belt-shaped member that is thermally shrunk. According to this, when the band-like member is heat-welded by the heat-welding mechanism, the band-like member is relaxed, so that the length of the heat shrinkage due to the heat-welding is absorbed. [Example] Hereinafter, an example in which the heat welding device according to the present invention is used for manufacturing a carrier bag with a handle will be described with reference to the drawings. Note that descriptions of parts that are the same as or similar to those of the conventional heat welding apparatus will be omitted or simplified. In FIG. 2, the gazette tube 1 is transferred to a heat welding mechanism 5 after passing through a dancer mechanism 4 as a buck tension application mechanism. A tension adjustment roll 11 is provided between them.
As shown in FIG. 3, the gazette tube 1 is an annular band-shaped member having both ends folded inward by a predetermined length. A tension adjustment mechanism is constituted by the tension adjustment roll 11 and the feed roll 6 provided on the transfer side of the heat welding mechanism 5. Further, the tension adjustment roll 11 and the feed roll 6 are configured to be interlocked with each other, and when heat welding is being performed by the heat welding mechanism 5, the rotation of the tension adjustment roll 11 together with the feed roll 6 is stopped. Heat welding is usually
The temperature is 200-250°C and the number of shots is 50-100 times/min. Note that, except during heat welding, the feed roll 6
is rotating, the tension adjustment roll 11 is also rotating. Gazette tube 1 with tension adjustment roll 11
The feed amount is greater than the feed amount by the feed roll 6.
It is assumed that the length of the gazette tube 1 is increased by the length that is thermally contracted due to heat welding. That is, in normal bag making, the amount of feed by the tension adjusting roll 11 is increased by about 1 mm for one bag. Gazette tube 1 with tension adjustment roll 11
As a specific method for making the feed amount larger than the feed amount by the feed roll 6, the tension adjustment roll 11
The rotation speed of the tension adjustment roll 11 and the feed roll 6 are assumed to be constant. For example, if the rotation speed of the tension adjustment roll 11 and the feed roll 6 are the same, the diameter of the tension adjustment roll 11 is set to be smaller than the diameter of the feed roll 6. , it is sufficient to increase the size by an amount corresponding to the heat shrinkage due to heat welding. In addition, if the tension adjustment roll 11 has a considerably larger diameter than the feed roll 6, the tension adjustment roll 11 is rotated by an angle corresponding to the larger diameter at a small rotation angle that is inversely proportional to the larger diameter. Just let it happen. Gazette tube 1 with tension adjustment roll 11
Another specific method for making the feed amount larger than the feed amount by the feed roll 6 is to make the rotation speed of each of the tension adjustment roll 11 and the feed roll 6 variable, and adjust the tension by setting a timer. The roll 11 may rotate more than the feed roll 6 by an amount equivalent to heat shrinkage in terms of circumference. The heated and welded gazette tube 1 sent out from the feed roll 6 is sealed and cut into one carrier bag by a cutter blade 7 with a heat seal bar as shown in FIG. 4, and one end is opened and removed. Carrying bag 10 having an outlet 8 and a handle 9
is formed. In addition, the reference numeral 21A in the figure is a heat-welded part for the handle part, and 21B is a heat-welded part for the bottom part. According to such a heat welding device, when the heat welding mechanism 5 heat-welds the gazette tube 1, the gazette tube 1 is relaxed and can therefore absorb the length of heat contraction, and the heat-welded portion is 21A, 21B, especially the welded edges are not stretched thin, so the welded parts 21A, 21B
This has the effect of significantly increasing the strength of the In addition, since the carrier bag 10 with the handle portion 9 having excellent strength can be formed, the heat-welded portion 2 for the bottom portion
Combined with the increased strength of 1B, it is possible to provide a carrier bag that can store and carry extremely heavy luggage. In addition, in the above description, the heat-welded part is provided on the handle part and the bottom part, but the heat-welded part is not limited to the part formed on the handle part and/or the bottom part, but may be provided in other places. good. Next, the present invention will be explained in more detail with reference to the following test results. Test Results Gazette tubes of various thicknesses made of high-density polyethylene were heat-welded under the following heat-welding conditions, and the mechanical strength of the heat-welded portion was tested using the following test method. Table 1 shows the results. B Heat welding conditions Temperature of heat welding bar 220℃ Number of rotations of feed roll ^* 70rpm * Number of rotations of feed roll The circumference of the feed roll is equal to the width of one bag, and the circumference of the tension adjustment roll is the same as that of the feed roll. A piece 1 mm longer than the circumference was used. (b) Test method After cutting the tube perpendicular to the heat-welded part so that the heat-welded part is divided into eight equal parts, the cut pieces are overlapped and punched out using a polyethylene dumbbell to form a test piece. This test piece was subjected to impact tension using a universal buffer testing machine (capacity: 30 kg cm) manufactured by Toyo Seiki Co., Ltd., and the mechanical strength was evaluated based on the energy required to break the heat-welded portion of the test piece.

[Effect of idea]

According to the present invention, even if there is a back tension application mechanism that applies tension to the belt-like member, the heat-welded part, especially the welded line, will not be stretched thin, and therefore a strong carrier bag can be manufactured. become.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a conventional heat welding device, FIG. 2 is a schematic diagram showing an embodiment of the heat welding device according to the present invention, FIG. 3 is a perspective view showing the shape of the gazette tube, and FIG. The figure is a front view showing the appearance of the carrier bag manufactured according to the above-described embodiment. DESCRIPTION OF SYMBOLS 1...Synthetic resin gazette tube as a belt-shaped member, 4...Dancer mechanism as a back tension application mechanism, 5...Heat welding mechanism, 6...Feed roll, 11...Tension adjustment roll.

Claims (1)

[Scope of utility model registration request] a back tension applying mechanism that applies tension in the longitudinal direction to the supplied band member; a handle portion of a carrier bag formed from the band member, which is provided on the feeding side of the band member from the back tension applying mechanism; The handle portion and/or the bottom portion of a carrier bag is configured to include a heat welding mechanism for heat welding a portion corresponding to the bottom portion, and a feed roll provided on the feed side of the band-like member from the heat welding mechanism. In the heat welding device, a device is provided between the back tension application mechanism and the heat welding mechanism, the belt member is loosened before heat welding by the heat welding mechanism, and rotates in conjunction with the feed roll. , and a handle for a carrier bag, characterized in that a tension adjustment roll is provided, the amount of feeding of the band-like member being larger by the length of the band-like member being heat-shrinked due to heat welding than the amount of feeding of the band-like member by the feed roll. and/or bottom heat welding equipment.