JPH0543479B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for cutting plastic film.

Structure of the prior art and its problems FIG. 5 shows a conventional plastic film fusing device. This device is for manufacturing plastic film bags by melt-cutting plastic film PF that is folded in half. guided between. The comb-like members 1H and 1L are inserted into the outer circumferential groove of the feed roll 2. Therefore, the plastic film PF can be fed by the feed roll 2 and guided by the comb-like members 1H and 1L.

Furthermore, this device has a hot blade 3, a holding member 4 and a receiving member 5. The heat blade 3 has a built-in heater 6 and is made of a heat transfer material such as metal. The receiving member 5 is roll-shaped and made of heat-resistant rubber such as silicone rubber.
PF is between the holding member 4 and the receiving member 5, and the hot blade 3
and the receiving member 5, and is intermittently fed a fixed length at a time, and guided between a pair of upper and lower stacker belts 7.

Each time the plastic film PF is fed, the hot blade 3 and the presser member 4 are operated by a drive mechanism such as a cylinder, and the hot blade 3 and the presser member 4 are respectively lowered. Therefore, first, the plastic film PF is sandwiched between the holding member 4 and the receiving member 5, and the plastic film PF is held down by the holding member 4. Thereafter, the spring is elastically deformed between the drive mechanism and the holding member 4, and the holding member 4 does not descend any further, but only the hot blade 3 further descends. Therefore, plastic film PF
is sandwiched between the hot blade 3 and the receiving member 5, and the plastic film PF is pressurized and heated by the hot blade 3 to be fused and cut. In addition, plastic film
When the PF is fused, the fused part melts,
Welded. Therefore, plastic film
Bags can be manufactured using PF.

After that, the hot blade 3 is operated by the drive mechanism,
The heat blade 3 rises by itself by a certain distance. Regarding the holding member 4, a spring acts on the holding member 4, and the holding member 4 is kept pressed against the plastic film PF and the receiving member 5.
Therefore, the plastic film PF is held down by the holding member 4, and the hot blade 3 is separated from the plastic film PF. Thereafter, the action of the spring is released, and the holding member 4 also rises together with the hot blade 3. Furthermore, each stacker belt 7 is closed by the drive mechanism, and the plastic film is
The PF is sandwiched between each stacker belt 7, and the plastic film PF is held by the stacker belt 7.
is pulled. Therefore, the plastic film PF is released from the receiving member 5. The plastic film PF passes between each stacker belt 7 and is sent to the outside. Regarding the receiving member 5,
The outer periphery of the plastic film PF is covered with a highly releasable Teflon sheet, so that when the plastic film PF is pulled away from the receiving member 5, it can be pulled off smoothly. This process is repeated in sequence.

However, this device had a problem with the welding strength of the plastic film PF. In the case of this device, the plastic film PF is heated by the hot blade 3.
is heated and melted because the plastic film PF is sandwiched between the hot blade 3 and the receiving member 5.
This is only the time when the plastic film PF is pressurized by the PF. plastic film PF
After fusing, the hot blade 3 is lifted and simultaneously pulled away from the plastic film PF. Therefore, when the pressurized state of the plastic film PF is released, the plastic film PF is no longer heated. Therefore, the plastic film PF can only be heated under pressure and cannot be sufficiently melted. For this reason, the plastic film PF could not be effectively welded, resulting in a problem of low welding strength.

Purpose of the Invention Therefore, the present invention provides a method for cutting a plastic film using a hot blade, in which the plastic film is continuously heated when the pressurized state of the plastic film is released after the plastic film is melted. This was done for the purpose of effectively welding and increasing the welding strength.

Structure of the Invention According to the present invention, after the plastic film is fused, the heating blade and the holding member are raised integrally by a certain distance. Therefore, the plastic film sticks to the hot blade and the hot blade is not pulled away from the plastic film. Therefore, even if the pressurized state of the plastic film is released, the plastic film continues to be heated. Thereafter, only the hot blade is further raised, the plastic film is held down by the holding member, and the hot blade is separated from the plastic film.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described. FIG. 1 shows an embodiment of the invention. This device has a thermal blade 3 and a receiving member 8. Thermal blade 3 is the thermal blade 3 in Figure 5.
It is arranged above the receiving member 8. The receiving member 8 replaces the receiving member 5 shown in FIG. 5, and is shaped like a pedestal with a built-in heater 9. The receiving member 8 is made of a heat conductive material such as metal, and is guided so as to be able to rise and fall. A drive mechanism such as a cylinder is transmission connected to the receiving member 8,
When the plastic film PF is melted, the receiving member 8 is operated by the drive mechanism and raised. Further, a heat-resistant rubber 10 such as silicone rubber is provided on the receiving member 8, and a sheet made of polytetrafluoroethylene with high releasability is attached to the heat-resistant rubber 10.
0 is covered.

Furthermore, this device has a pair of upper and lower comb-like members 11.
H, 11L. Comb-shaped members 11H, 11L
is an extension of the comb-shaped members 1H and 1L shown in FIG.
and the receiving member 8. Therefore,
The plastic film PF is sent and guided by the feed roll 2 and comb-like members 11H and 11L,
This can be passed between the hot blade 3 and the receiving member 8 and guided between each stacker belt 7. Further, among the comb-shaped members 11H and 11L, the upper comb-shaped member 11H has appropriate elasticity and extends to the position of the hot blade 3. The tip 12 acts as a holding member.

In this device, plastic film PF
When the comb-shaped member 11H is melted, the hot blade 3 is operated by the drive mechanism, and when lowered, the hot blade 3 touches the comb-shaped member 11H.
The hot blade 3 presses down the tip 12 of the comb-shaped member 11H. The comb-shaped member 11H is elastically deformed accordingly. Therefore, the hot blade 3 and the tip 12 of the comb-like member 11H each descend. At the same time, the receiving member 8 is operated by the drive mechanism and raised.

Therefore, as shown in FIG. 2, the plastic film PF is sandwiched between the tip 12 of the comb member 11H and the receiving member 8, and the plastic film PF is held down by the tip 12 of the comb member 11H. Further, the plastic film PF is sandwiched between the thermal blade 3 and the receiving member 8, and the thermal blade 3 and the plastic film PF are connected to the heat-resistant rubber 10 of the receiving member 8.
be forced to. Therefore, the plastic film PF is pressurized and heated by the heating blade 3. Furthermore, the receiving member 8 acts as a heat transfer medium, and the heat-resistant rubber 10 is heated by the heater 9. Therefore, the plastic film PF can be heated by the receiving member 8. Therefore, the plastic film PF is heated by the heating blade 3 and the receiving member 8 and is fused. Further, when the plastic film PF is melted, the melted portion is melted and welded. Therefore, bags are manufactured using plastic film PF.

Further, in the case of this device, when the hot blade 3 and the plastic film PF are pressed against the heat-resistant rubber 10 of the receiving member 8, the heat-resistant rubber 10 is elastically deformed accordingly. Therefore, even if the processing accuracy of the hot blade 3 is low and its deflection is large, the deflection of the hot blade 3 can be absorbed by the heat-resistant rubber 10. Therefore, the plastic film PF can be reliably melted over its entire width.

Furthermore, in the case of this device, after the plastic film PF is fused, the operating mechanism operates the thermal blade 3 to raise it, and the drive mechanism operates the receiving member 8 to lower it. Therefore, the pressurized state of the plastic film PF is released. Furthermore, when the hot blade 3 rises, the tip 12 of the comb-like member 11H is pulled up by the elasticity of the comb-like member 11H.
The tip 12 of 1H follows the hot blade 3 and rises together with the hot blade 3. Along with this, the comb-shaped member 11H
The elastic deformation of is corrected. Therefore, the hot blade 3 and the tip 12 of the comb member 11H rise integrally by a certain distance l, and the plastic film PF adheres to the hot blade 3, and the plastic film PF is pulled up by the hot blade 3, and Blade 3 is not separated from the plastic film PF. Therefore, when the pressurized state of the plastic film PF is released, the plastic film PF continues to be heated, and the plastic film PF is sufficiently melted. Therefore, the plastic film PF can be effectively welded and the welding strength can be increased. The rising distance l is preferably 2 to 3 mm.

Thereafter, when the elastic deformation of the comb-shaped members 11H, 11L is corrected, the comb-shaped member 11H is restored to its original state, its tip 12 does not rise any further, and only the hot blade 3 rises further. Therefore, the plastic film PF is retained by the tip 12 of the comb-like member 11H, and the thermal blade 3 is separated from the plastic film PF. At the same time,
The stacker belts 7 are operated by the drive mechanism, the plastic film PF is sandwiched between the stacker belts 7, and the plastic film PF is pulled by the stacker belts 7. Therefore, the plastic film PF is pulled away from the melted part and passed between each stacker belt 7,
Sent externally. As for the receiving member 8, a heat-resistant rubber 10 is covered with a Teflon sheet having high releasability, so that when the plastic film PF is separated from the receiving member 8, it can be pulled off smoothly.

Note that various modifications can be made to this invention. For example, as shown in FIG. 3, a swingable movable member 13H may be used as a holding member for the plastic film PF in place of the comb-shaped member 11H shown in FIG. The movable member 13H is swingably supported around the fulcrum 14 and is disposed above the fixed member 13L. Furthermore, the weight 15 acts on the movable member 13H, and the movable member 13H contacts the stopper 16 and is kept horizontal. Therefore,
The plastic film PF is passed between the movable member 13H and the fixed member 13L, and the plastic film PF is
can be guided between the hot blade 3 and the receiving member 8.

In this device, plastic film PF
When the heating blade 3 is fused, the driving mechanism operates the heating blade 3 and lowers the inclined surface 17 of the heating blade 3 into contact with the tip 18 of the movable member 13H. The movable member 13H swings around the fulcrum 14. Therefore, the thermal blade 3 and the tip 18 of the movable member 13H each descend. At the same time, the receiving member 8 is operated by the drive mechanism and raised. Therefore, the plastic film PF is the movable member 13.
The tip 18 of the movable member 13H is sandwiched between the tip 18 of the movable member 13H and the receiving member 8, and between the thermal blade 3 and the receiving member 8.
The plastic film PF is held down by
The plastic film PF is pressurized and heated by the hot blade 3 and is fused.

After cutting the plastic film PF,
When the heat blade 3 and the receiving member 8 are operated by the drive mechanism and are raised and lowered, the weight 15 acts on the movable member 13H, and its tip 18 touches the heat blade 3.
It follows and moves together with the heat blade 3. Therefore, the thermal blade 3 and the tip 18 of the movable member 13H can be raised integrally by a certain distance l. Therefore, the plastic film PF can be sufficiently melted, it can be effectively welded, the welding strength can be increased, and the same effects can be obtained. After that, when the movable member 13H comes into contact with the stopper 16, its tip 18 does not rise any further;
Only the hot blade 3 is further raised, and the hot blade 3 is separated from the plastic film PF.

In addition, as shown in FIG.
9 may be transmission connected to the movable member 13H. When the movable member 13H is operated by the air cylinder 19 to melt and cut the plastic film PF, the plastic film PF is pressed by the tip 18 of the movable member 13H. After that, when the hot blade 3 rises, the hot blade 3 and the tip 18 of the movable member 13H
By raising them integrally by a certain distance l, the plastic film PF can be effectively welded and the welding strength can be increased.

Effects of the Invention As explained above, according to the present invention, when the pressurized state of the plastic film PF is released, the plastic film PF is continuously heated,
This can be sufficiently melted. As a result, the plastic film PF can be effectively welded, its melting strength can be increased, and the intended purpose can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the invention, Fig. 2 is a side view showing an embodiment of the present invention;
The figure shows the plastic film shown in Figure 1 being pressed down.
Explanatory diagrams showing the state of being fused, Figures 3 and 4
This figure is a side view showing another embodiment, and FIG. 5 is a side view of a conventional plastic film fusing device. 3... Heat blade, 8... Receiving member, 11H... Comb-shaped member, 13H... Movable member, 15... Weight, 16... Stopper, 19... Air cylinder.

Claims (1)

[Claims] 1. A heating blade and a pressing member are placed above the receiving member, the heating blade and the pressing member are respectively lowered, a plastic film is sandwiched between the pressing member and the receiving member, and between the heating blade and the receiving member, and the A method of holding down the plastic film with a holding member and cutting the plastic film with the heating blade, the method comprising: raising the heating blade and the holding member integrally by a certain distance after cutting the plastic film; 2. A method for fusing and cutting a plastic film, characterized in that the heating blade is moved upward, and then only the heating blade is further raised to separate the heating blade from the plastic film.