JPH0223521Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is designed to transport a large number of trays containing items to be packaged at regular intervals by a conveyor, while moving the cylindrical plastic film that covers each tray to the front and back of each tray. The present invention relates to a film folding device for a packaging machine, in which the ends of the film are pulled toward the ground by an air flow, and both ends of the film are bent to the lower surface of each tray to seal the trays.

(Prior art) Products in which fresh food is stored in a plastic tray, the tray is covered with a cylindrical transparent stretchable film, and both ends of the film are bent under the tray are often sold in supermarkets. It can be seen in the market. Conventionally, as shown in FIG. 5, a device for folding the end of the film into the bottom surface of a tray cuts a cylindrical film 2 covered on a tray using a guillotine-shaped cutting mechanism 8 and a lower blade 9. , the ends 2a and 2b of the cut film are sucked into the suction ports 3 and 4 of an air suction machine such as a vacuum pump, and while being pulled in the direction of the ground, the running force of the bar 6 attached to the chain 5 and the direction of the arrow 7 of the tray 1 are applied. With this conveying force, the ends 2a and 2b of the film are folded into the lower surfaces of the trays 1 and 1, respectively.

(Problems to be Solved by the Invention, etc.) However, in the above-described device, the end 2b of the film on the front side of the tray 1 is inevitably flat and cannot be folded into the lower surface of the tray. That is, the reason is that when the tray 1 passes over the suction port 4 as shown by the arrow as shown in FIG. 6, it will move from the solid line in the direction of the virtual line 1a, As the upper surface of the suction port 4 is closed, the air volume from both sides of the tray increases as shown by the arrows in FIG. This means that it will be bent to the bottom of the tray. If the edges of the film remain shrunken like this,
Because the film is too thick, it cannot be welded to the bottom of the tray, and the tray is not stable. Moreover, the film 2b does not come into contact with the suction port 4, and there is no contact friction between the film and the suction port, so that the film cannot be effectively stretched.

In view of the above-mentioned points, an object of the present invention is to provide a folding device that can fold the edge of the film toward the lower surface of the tray in a flat and fully stretched state in the direction of travel of the tray, especially on the front side of the tray. That is.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a continuous cylindrical film in which a large number of trays arranged at equal intervals are sandwiched from both sides to perform a conveying action. In the middle of the pair of side belts, a blade in the lower part and a reverse groove-shaped guillotine in the upper part are provided to cut the film between each tray, and two guillotines connected to a vacuum pump are installed in front and behind the blades. Suction chambers are provided, and the ends of the film cut by the mechanism described above are pulled into the suction ports on the upper surface of these suction chambers. The ends of the film sucked into the rear suction chamber are hooked onto a rotary perforated belt that surrounds the suction chamber, and the ends of the film are folded onto the bottom surface of the tray. A roll is provided on the rim on the front side of the suction port in the side suction chamber, and a guide plate is provided substantially horizontally below the roll, and between the guide plate and the rim of the suction chamber. An air guide gap is formed toward the rear wall of the chamber.

(Operation) The cylindrical tube covered with the tray is separated by the upper guillotine and the lower blade, and at the same time, the two separated ends are sucked into the two suction chambers. After this, if the suction chamber at the upper end is blocked by the advancing tray, especially for the suction chamber on the front side in the direction of tray movement, a formation will occur between the guide plate and the rim of the suction port. The suction of air from the air guide gap gradually increases, and the ends of the separated film are pressed against the rear wall of the suction chamber, and the ends of the film are narrowly overlapped by the air sucked in from both sides of the suction chamber. In addition to preventing this, the contact friction between the film and the suction chamber is increased to assist the stretching of the film.

(Example) Although only one side of the side belt 10 is shown in FIG. 1, the side belt 10
are provided on both sides of the tray T as shown in FIG. It is designed to be continuously transported in 11 directions. Furthermore, cutting mechanisms 12 are provided above and below the side belts 10, 10 on both sides. The mechanism consists of an upper guillotine 13 and a lower blade 14, and the guillotine 13 has an inverted groove-shaped member and horizontal wing plates 15, 15 at the front and rear thereof, respectively. Further, two suction chambers 17 and 18 connected to a vacuum pump are provided before and after the blade 14 of the cutting mechanism, and suction ports 19 and 20 formed on the upper surface of these chambers are opened at the front and rear of the blade 14, respectively. are doing. Furthermore, a plurality of rotors 22 and 22 are provided with a perforated rotary band 21 for folding the film so as to surround the front suction chamber 17.
22... is supported and arranged. On the other hand, a round bar-shaped roll 23 is rotatably installed above the rear edge of the suction port 20 of the rear suction chamber 18 with its upper surface slightly higher than the lower surface of the tray T.

On the other hand, the blade 14 is fixed to the front wall of the rear suction chamber 18 via screws 16, and a predetermined gap is formed between the suction chamber 18 and the blade 14, A film protection plate 27 is installed in the gap so as to be slidable in the vertical direction, and a spring 28 that engages the protection plate 27 with the suction chamber 18 causes the upper surface of the protection plate to be raised above the cutting edge of the blade 14. It is positioned so that it protrudes. Further, a guide plate 30 is provided below the roll 23, and a narrow air guide gap 25 in the horizontal direction is provided between the guide plate 30 and the mouth edge of the suction chamber 18 below the guide plate. A portion is formed facing toward the plate 27.

However, in Fig. 1, the side belts 1 on both sides
A cylindrical film F has already been placed around each of the trays T and T, which are being held and transported by the trays 0 and 10, by a tube-making device installed at a location other than the drawing. On the other hand, the guillotine 13 is normally stopped at approximately the height shown in the figure so that the tray T can pass under it.
When it passes under the guillotine, a series of power transmission mechanisms (not shown) consisting of cams, levers, and links connected to the guillotine cause the guillotine 13 to move downward as shown in Figure 3, and cut the film F with the blade 14. . In this case, a push pin (not shown) provided on the link that moves the guillotine 13 downward acts on the end of the film protection plate 27, and moves the film protection plate 27 synchronously with the guillotine 13 while stretching the spring 28. Since the blade 14 is moved downward, cutting of the film by the blade 14 is not hindered. Due to this action, the front end F1 of the film is pulled into the suction chamber 18 from the suction port 20, as shown in FIG. In this case, there are two types of air flow in the suction chamber 18 as indicated by arrows a and b. One of them is the main flow a that is sucked into the suction port 20 and the auxiliary flow b that is sucked through the air guide gap 25. The main flow a is the edge F of the film
1 toward the ground, and the auxiliary flow b flows laterally to help the film end F1 come into contact with the front wall of the suction chamber or the film protection plate 27. Since the main flow sucking the end F1 of the film into the suction port 20 initially flows directly downward, the end of the film remains cut, that is, pulled toward the ground over a relatively wide width. Then, by moving the tray T in the direction of the arrow 11, the suction port 2
As the blocked area of the film 0 increases, the flow rate of the auxiliary flow b increases, and the end F1 of the film is forcefully pressed toward the protection plate 27, and as the tray T moves 11, it is bent onto the lower surface of the tray. At this point, guillotine 13 has already returned to the upper position,
The film protection plate 27 protrudes above the cutting edge of the blade 14 by the reaction force of the spring 28 to protect the film from being cut and to apply friction to the film to help tension the film.

On the other hand, the end F2 of the film located at the rear of the front tray in FIG.
7 and is bent onto the lower surface of the tray by the action of the perforated rotating band 21 which rotates at a higher speed than the tray T.

(Effects) The film folding device of the present invention forms an air guide gap 25 on the lower side of the protection plate 30, and directs the end F1 of the film toward the ground using the air flow a sucked from the suction port 20 of the suction chamber. The end F1 of the film is pressed against the rear wall of the suction chamber 18 while maintaining its width by the air flow b sucked in from the air guide gap 25 while being pulled, and the closed area of the suction port 20 is reduced by the tray T. When the width increases, the auxiliary flow rate from the air guide gap 25 also increases automatically, and the pressing force on the film edge F1 increases, so even if the amount of air sucked from both sides of the tray increases, the film edge F1 can be maintained wide. It can be folded to the bottom of the tray while remaining as it is. Therefore, the end F1 of the film can be tightly welded to the bottom of the tray, and a tray-wrapped product with good stability can be obtained.Furthermore, the film can be stretched by pressing the end F1 of the film against the rear wall of the suction chamber, making it possible to perform tension packaging. There are other effects.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is a simplified plan view of the previous figure, Figs. 3 and 4 are partial action explanatory diagrams of Fig. 1, and Fig. 5 is a conventional example. Explanation: FIG. 6 is a plan view of the previous figure, and FIG. 7 is a sectional view taken along the - line of the previous figure. 10... Side belt, 12... Cutting mechanism, 1
3... Guillotine, 14... Blade, 17, 18... Suction chamber, 19, 20... Intake port, 21...
Perforated rotating band, 23...Sponge roll, 25...
...Air guide gap, 27...Film protection plate, 30
...information board, T...tray, F...film.

Claims (1)

[Scope of utility model registration request] The film F is placed in the middle of a pair of side belts 10, 10, which carry a large number of trays T, T, etc. arranged at equal intervals inside a continuous cylindrical film F, by sandwiching them from both sides. A blade 14 is provided on the lower side and a reverse groove-shaped guillotine 13 is provided on the upper side for cutting between the two suction chambers 1 connected to a vacuum pump before and after the blade 14.
7 and 18 are provided, and the films F1 and F2 cut by the cutting mechanism are pulled into the suction ports 19 and 20 on the upper surface of these suction chambers, and the films sucked into the suction chamber 18 on the front side in the direction of movement of the tray. The end F1 of the film is hooked by the conveying force of the tray, and the end F2 of the film sucked into the suction chamber 17 on the rear side is hooked by a perforated rotating belt that surrounds the suction chamber, and bent onto the bottom surface of the tray. In this packaging machine, a guide plate 30 is provided substantially horizontally on the front wall edge of the suction port 20 in the front suction chamber 18, and the guide plate 30 and the mouth of the suction chamber 18 are provided in a substantially horizontal manner. A horizontally elongated air guide gap 25 is formed between the air guide gap 25 and the air guide gap 25, and as the suction port 20 at the top of the suction chamber is closed by the tray T, an elongated air guide gap 25 is formed from the air guide gap 25 toward the rear wall of the suction chamber. A film folding device for a packaging machine that gradually increases intake air.