Title:
VERTICAL FILLING AND PACKING MACHINE
Kind Code:
A1


Abstract:
A vertical filling and packing machine comprises film feed roller (6) for feeding tubular film (20) in a vertical downward direction, a folding device for folding opposing sides of tubular film (20) carried by film feed roller (6) inwardly of tubular film (20), a pair of squeeze rollers (7) for forming an empty portion in the tubular film by rotating while sandwiching the tubular film filled with contents and feeding the tubular film downwardly, and sealing device (8) for heat sealing the tubular film. The folding device includes folding guide (2) which has clearances formed at portions corresponding to the opposing sides of tubular film (20) and supports the outside of tubular film (20), and a pair of folding plates (5) capable of advancing/retracting into/from folding guide (2) through the clearances formed in folding guide (2).



Inventors:
Tsuruta, Orihiro (Takasaki-shi, JP)
Yamaguchi, Akira (Takasaki-shi, JP)
Application Number:
12/447879
Publication Date:
02/18/2010
Filing Date:
11/07/2006
Assignee:
ORIHIRO CO., LTD. (Takasaki-shi, Gunma, JP)
Primary Class:
International Classes:
B65B9/20; B65B9/213; B65B39/00; B65B51/10
View Patent Images:



Primary Examiner:
TECCO, ANDREW M
Attorney, Agent or Firm:
KNOBBE MARTENS OLSON & BEAR LLP (IRVINE, CA, US)
Claims:
1. 1-8. (canceled)

9. A vertical filling and packing machine, comprising: a feed device for feeding a tubular film filled with contents vertically downward; a pair of squeeze rollers for forming an empty portion in the tubular film by rotating the tubular film while sandwiching the tubular film filled with contents and feeding the tubular film downwardly; and a sealing device which is provided with sealing bars opposite to each other with the tubular film interposed therebetween and which performs heat sealing onto the tubular film interposed between the sealing bars, wherein each of the pair of squeeze rollers is provided on one end of a squeeze roller arm the other end of which is supported in a rotatable manner, and includes an open/close driving unit for rotating each squeeze roller arm independently of each other about the other end of the squeeze roller arm, between a closed position for bringing the pair of squeeze rollers mutually into contact with each other and an opened position for spacing the pair of squeeze rollers from each other.

10. The vertical filling and packing machine of claim 9, wherein the open/close driving unit includes a first arm having one end connected to one of the squeeze roller arms, a second arm having one end connected to the other of the squeeze roller arms, a rotatable shaft to which other ends of the first arm and the second arm are connected, and a driving part for driving the rotatable shaft, and the other ends of the first arm and the second arm are connected to the rotatable shaft in the state where the other ends of the arms are eccentric from the rotation center of the rotatable shaft, and when the rotatable shaft is located at a first rotating position, one of the squeeze roller arms is pushed toward the position of getting farther from the rotatable shaft through the first arm and the other of the squeeze roller arms is pulled toward the position of getting closer to the rotatable shaft through the second arm, thereby placing the first and second squeeze roller arms at an opened position for spacing the pair of squeeze rollers apart from each other, and when the rotatable shaft is located at a second rotating position, one of the squeeze roller arms is pulled toward the position of getting closer to the rotatable shaft through the first arm and the other of the squeeze roller arms is pushed toward the position of getting farther from the rotatable shaft through the second arm, thereby placing the first and second squeeze roller arms at a closed position for bringing the pair of squeeze rollers into contact with each other.

11. The vertical filling and packing machine of claim 9, wherein a holding portion formed by the pair of squeeze rollers is located on a center line of the pass route for the tubular film when the pair of squeeze rollers are positioned at the closed position.

12. The vertical filling and packing machine of claim 9, further comprising a folding device for folding opposing sides of the tubular film fed by the feed device inwardly of the tubular film; the folding device includes a folding guide which has clearances formed at portions corresponding to sides of the tubular film that are opposite to each other and which supports an outside of the tubular film, and a pair of folding plates capable of advancing/retracting into/from the folding guide through the clearances formed in the folding guide.

13. The vertical filling and packing machine of claim 12, wherein the folding guide is composed of two semi-cylindrical guide members and is oppositely disposed to each other so that the folding guide forms into an approximately cylindrical shape with the clearances therebetween.

14. The vertical filling and packing machine of claim 12, wherein each of the pair of folding plates has an oblique side which gets closer to the center line of the pass route for the tubular film toward downstream in the feed direction of the tubular film.

15. The vertical filling and packing machine of claim 12, comprising an advance/retract driving unit for moving the pair of folding plates to a position in which the folding plates are closer together and in which the folding plates advance into an inside of the folding guide, and to a position in which the folding plates are in which they retract spaced from each other and retracted toward an outside of the folding guide.

16. The vertical filling and packing machine of claim 9, wherein the sealing bar has a lateral sealing portion extending in a lateral direction of the tubular film, and wherein the sealing bar has a pair of oblique sealing portions formed above and below the lateral sealing portion, respectively.

Description:

TECHNICAL FIELD

The present invention relates to a vertical filling and packing machine for producing a packing bag by performing a series of operations of filling a tubular film with a liquefied or paste filling material and heat sealing the film filled with the filling material.

BACKGROUND ART

There has hitherto been known a vertical filling and packing machine that produces a packing bag by filling a tubular film with a liquefied or paste filling material and by heat sealing the film filled with the filling material. The vertical filling and packing machine of this type has proven to be appropriate for filling and packing foodstuffs since the machine can produce packing products that the inside is sealed. In addition, the vertical filling and packing machine has been widely used for packing a liquefied or paste filling material as well as a solid filling material.

Recently, a packing bag called a gusset pouch has been used in which the opposite sides of the pouch are folded inwardly. Since such a gusset pouch is formed into a prismatic shape when filled with contents, it is possible to eliminate unnecessary spaces among gusset pouches arranged adjacently with each other. This serves to allow gusset pouches to be efficiently used when shipped in boxes or when displayed in shops.

Gusset pouches can be produced by using the above-described vertical filling and packing machine equipped with a folding guide apparatus for folding opposing side walls of the pouch.

FIG. 1 is a perspective view of a conventional folding guide apparatus equipped to a vertical filling and packing machine. As shown in FIG. 1, a conventional folding guide apparatus includes two pairs of guide arms 103 and two folding plates 104 arranged in the vicinity of the bottom of injection pipe 102 for injecting a filling material into tubular film 101. Guide arms 103 are provided in pairs on opposing sides of injection pipe 102 in such a manner that guide arms 103 pull and open tubular film 101 into an approximately rectangular shape.

Folding plates 104 are disposed outside tubular film 101 and respectively between two guide arms 103 arranged on opposing sides of injection pipe 102. Each of folding plate 104 has oblique side 104a which gets closer to the center line of a pass route for tubular film 101 as regards the feed direction of tubular film 101, that is, in the direction from the top towards the bottom of the vertical filling and packing machine.

In the folding guide apparatus having the above-described configuration, tubular film 101 carried downwardly from the upside is pulled and opened by guide arms 103 such that the cross sectional surface of the film becomes approximately rectangular. When tubular film is carried further downwardly, part of tubular film 101 which passes through the space between guide arms 103 provided on opposing sides of injection pipe 102 is folded in a V-shape along oblique side 104a of folding plate 104 interposed between guide arms 103. In the meantime, FIG. 1 shows tubular film 101 with a cut plane simply for convenience of understanding the shape of the cross sectional surface of tubular film 101 which is thus-folded. However, it should be understood that cutting of tubular film 101 as shown in FIG. 1 will not occur in the actual packing process.

When tubular film 101 in which opposing sides are folded inwardly into a V-shape is filled with contents and sealed, gusset pouch 105 having the sides at which gusset portions 105a are formed can be obtained, as shown in FIG. 2.

Japanese Patent Application Laid-Open No. 2003-118745 discloses a filling and packing machine provided with means for forming a folded portion into a tubular film.

DISCLOSURE OF THE INVENTION

However, the above-described folding guide apparatus has drawbacks in that the filling material introduced into tubular film 101 from injection pipe 102 may stick to guide arms 103. In cases where the filling material is a liquefied or paste type, the filling material that becomes stuck to guide arms 103 may cause deterioration in the fluidity of the filling material in tubular film 101, which may result in mistakes in filling the filling material into tubular film 101. To keep the filling material clean, guide arms 103 need periodical cleaning, which makes maintenance of the filling and packing machine troublesome.

Therefore, it is an object of the present invention to provide a vertical filling and packing machine for producing a gusset pouch, capable of efficiently filling a tubular film with a filling material and making the maintenance thereof easy.

In order to accomplish the above object, a vertical filling and packing machine of the present invention includes a feed device for feeding a tubular film filled with contents vertically downward, a folding device for folding opposite sides of the tubular film fed by the feed device inwardly of the tubular film, a pair of squeeze rollers for forming an empty portion in the tubular film by rotating while sandwiching the tubular film filled with contents and feeding the tubular film downwardly, and a sealing device which is provided with sealing bars opposite to each other with the tubular film interposed therebetween and which performs heat sealing onto the tubular film interposed between the sealing bars. The folding device includes a folding guide which has clearances formed at portions corresponding to the opposing sides of the tubular film and supports the outside of the tubular film, and a pair of folding plates capable of advancing/retracting into/from the folding guide through the clearances formed in the folding guide.

In the vertical filling and packing machine of the present invention, the outside of the tubular film which is fed vertically downward by the feed device is supported by the folding guide when passing through the folding device. Here, if the tubular film is filled with contents, the film is pushed inwardly of the folding guide due to weight thereof. When the tubular film is carried further vertically downward in the state where the pair of folding plates has advanced into the folding guide through the clearances formed in the folding guide, opposing sides of the tubular film are folded inwardly while the tubular film is passing between the pair of folding plates. The tubular film with opposing sides folded inwardly as described above is heat sealed to be manufactured into a gusset pouch.

The folding device of the present invention includes a folding guide for supporting the outside of a tubular film, and a pair of folding plates capable of advancing/retracting into/from the folding guide through the clearances formed in the folding guide. This serves to prevent the filling material introduced in the tubular film from sticking to the folding guide or folding plates, which may otherwise take place in a conventional folding guide device having a guide arm for supporting the inside of the tubular film. Such an advantage of the present invention prevents the fluidity of the filling material in the tubular film from deteriorating due to the folding guide or folding plates, and thus prevents mistakes in filling the tubular film with the filling material. This allows for ease of maintenance of the filling and packing machine by eliminating the necessity of periodically cleaning the folding guide or folding plates to keep the filling material in the tubular film clean.

The folding guide is composed of two semi-cylindrical guide members, which may be oppositely disposed to each other in a cylindrical shape with the clearances therebetween.

Each of the pair of folding plates may have an oblique side which gets closer to the center line of pass route for the tubular film toward downstream in the feed direction of the tubular film.

The vertical filling and packing machine of the present invention may include an advance/retract driving unit for moving the pair of folding plates to a position where the folding plates are closed together and where they move into the inside of the folding guide and a position where the folding plates are spaced apart from each other and retract toward the outside of the folding guide.

The sealing bar may include a lateral sealing portion extending in a lateral direction of the tubular film, and a pair of oblique sealing portions formed above and below the lateral sealing portion, respectively. This construction allows lateral sealing and oblique sealing activities to be concurrently performed onto the tubular film. Since the corner of the part of a gusset pouch where oblique sealing is performed is kept free of filling material, swelling of a gusset portion caused due to the entry of filling material is prevented. This makes it easy to maintain the shape of the gusset pouch which is formed into a rectangular shape, and serves to allow gusset pouches to be efficiently used when shipped in boxes or when displayed in a shop.

In addition, each of the pair of squeeze rollers is provided on one end of a squeeze roller arm the other end of which is supported in a rotatable manner, and may include an open/close driving unit for rotating each squeeze roller arm independently of each other about the other end of the squeeze roller arm, between a closed position for contacting the pair of squeeze rollers mutually with each other and an opened position for spacing the pair of squeeze rollers apart from each other.

In addition, the open/close driving unit may include a first arm having one end connected to one of the squeeze roller arms in a rotatable manner, a second arm having one end connected to the other of the squeeze roller arms in a rotatable manner, a rotatable shaft to which other ends of the first arm and the second arm are connected in a rotatable manner, and a driving part for driving the rotatable shaft. The other ends of the first arm and the second arm are connected to the rotatable shaft in a state where the other ends of the arms are eccentric from the rotation center of the rotatable shaft. When the rotatable shaft is located at a first rotating position, one of the squeeze roller arms is pulled toward the position close to the rotatable shaft through the first arm and the other of the squeeze roller arms is pushed toward the position far from the rotatable shaft through the second arm, to thereby place the first and second squeeze roller arms at a closed position to enable the pair of squeeze rollers to come into mutual contact with each other. When the rotatable shaft is located at a second rotating position, one of the squeeze roller arms is pushed toward the position away from the rotatable shaft through the first arm and the other of the squeeze roller arms is pulled toward the position close to the rotatable shaft through the second arm, to thereby place the first and second squeeze roller arms at an opened position for spacing the pair of squeeze rollers apart from each other.

According to the structure described above, when the first and second squeeze roller arms are located at the closed position to enable the pair of squeeze rollers to come into mutual contact with each other, each of the squeeze roller arms rotates independently of each other, and one of the squeeze roller arms is pulled toward the position of getting closer to the rotatable shaft through the first arm and the other of the squeeze roller arms is pushed toward the position of getting farther from the rotatable shaft through the second arm. According to the structure, the pair of squeeze rollers contact each other in such a manner that the squeeze rollers push against each other. This structure permits the tubular film sandwiched between the squeeze rollers to be tightly squeezed. Therefore, even in cases where opposing sides of the tubular film are folded inwardly or in cases where the tubular film is filled with a filling material having high viscosity, the filling material can be easily divided in the inside of the tubular film.

When the pair of squeeze rollers is located at the closed position described above, it is desirable that a holding portion formed by the pair of squeeze rollers be located on the center line of the tubular film that is carried vertically downward. Accordingly, since the tubular film is kept between the pair of squeeze rollers on the center line of the pass route for the tubular film, opposing sides of the tubular film flattened by the pair of squeeze rollers are prevented from deviating from each other during squeezing operation of squeeze rollers, and wrinkle generation on the tubular film is prevented while heat sealing is being performed thereafter on the tubular film by the sealing device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a conventional folding guide apparatus provided in a vertical filling and packing machine;

FIG. 2 is a perspective view showing a conventional gusset pouch having both ends with gusset portions;

FIG. 3 is a schematic side view of a vertical filling and packing machine according to one embodiment of the present invention;

FIG. 4 is a view showing a detailed construction of film feed rollers, a folding guide, folding plates and squeeze rollers of the vertical filling and a packing machine shown in FIG. 3;

FIG. 5 is a view showing a squeeze roller opening/closing mechanism;

FIG. 6 is a view showing the construction of a K-shaped sealing bar of a sealing device;

FIG. 7 is a view showing the filling and packing operation conducted by the vertical filling and packing machine shown in FIG. 3;

FIG. 8 is a view showing the filling and packing operation conducted by the vertical filling and packing machine shown in FIG. 3;

FIG. 9 is a timing chart showing the filling and packing operation conducted by the vertical filling and packing machine shown in FIG. 3;

FIG. 10 is a perspective view showing a gusset pouch manufactured by the vertical filling and packing machine shown in FIG. 3;

FIG. 11 is a view showing the process of forming a gusset pouch into a rectangular shape by using a frame;

FIG. 12 is a view showing another construction of a K-shaped sealing bar; and

FIG. 13 is a perspective view of a gusset pouch manufactured by the K-shaped sealing bar shown in FIG. 12.

BEST MODE FOR CARRYING OUT THE INVENTION

An exemplary embodiment of the present invention is explained hereinafter with reference to the accompanying drawings.

FIG. 3 is a schematic side view showing a vertical filling and packing machine according to one embodiment of the present invention.

As shown in FIG. 3, the vertical filling and packing machine according to one embodiment of the present invention is designed to pack filling material A introduced through injection pipe 1. Filling material A consists of solid, liquefied or paste material. Along an outer circumference of injection pipe 1, there is attached bag-making guide 3 for forming sheet film 20a into a tubular shape. Tubular film 20 formed by bag-making guide 3 is heat sealed along a matching surface thereof by vertical sealing portion 4 provided below bag-making guide 3.

Below vertical sealing portion 4, there are provided a pair of film feed rollers 6 each of which is composed of two rollers. Film feed rollers 6 serve as a feed device for feeding tubular film 20 interposed therebetween.

Below film feed rollers 6, there is provided a folding device including folding guide 2 and folding plate 5 for folding opposing sides of tubular film 20 inwardly of the film. Folding guide 2 is composed of two semi-cylindrical guide members 2a which are disposed opposite to each other in an approximately cylindrical shape with clearances formed between them (Refer to FIG. 4(c)). Tubular film 20 is carried downward, passing two guide members 2a, while an outer periphery of tubular film 20 is being supported by two guide members 2a.

There are provided two sheets of folding plates 5 each of which is capable of advancing/retracting into/from folding guide 2 having two guide members 2a through the clearances formed between two guide members 2a. When tubular film 20 is carried downward in the state in which folding plates 5 are advanced into folding guide 2 having two guide members 2a, opposing sides of tubular film 20 are folded into a V-shape.

Below folding guide 2 and folding plates 5, there are provided a pair of squeeze rollers 7 constituted by two rollers which rotate in synchronization with the rotation of film feed rollers 6. Squeeze rollers 7 form empty portion 20b in tubular film 20 by dividing filling material A in tubular film 20 interposed between them. Squeeze rollers 7 are arranged such that they are reciprocally movable in an approximately vertical direction relative to the feed direction of tubular film 20.

Below squeeze rollers 7, there is provided sealing device 8 for heat sealing empty portion 20b of tubular film 20. Sealing device 8 has a built-in heater (not shown), and K-shaped sealing bars 80 which are movable vertically to the direction of movement of tubular film 20. Sealing device 8 is configured to place empty portion 20b of tubular film 20 between K-shaped sealing bars 80 and heat seal empty portion 20b through heating and pressing processes.

Below sealing device 8, there is provided cool cutting device 9 for cooling and cutting the portion heat sealed by sealing device 8. Cool cutting device 9 includes cooling bar 90 and cooling bar support 91 which cooperate with each other to cool the heat sealed portion formed in tubular film 20. Cooling bar 90 is equipped with built-in cutter blade 90a for cutting the heat sealed portion of tubular film 20. Cooling bar support 91 has a concave portion for receiving cutter blade 90a when the blade protrudes from cooling bar 90.

Now, detailed construction of film feed rollers 6, folding guide 2, folding plates 5 and squeeze rollers 7 of the vertical filling and packing machine according to the embodiment of the present invention will be described with reference to FIG. 4. FIG. 4(a) is a front elevation of the construction, FIG. 4(b) is a left side elevation of the construction shown in FIG. 4(a), and FIG. 4(c) is a plane view which mainly shows the folding guide that is a construction shown in FIG. 4(a).

As shown in FIG. 4, a pair of film feed rollers 6 are fixed at respective shafts 61 which are pivoted by support portion 62. One of shafts 61 has both ends to which one end of first squeeze roller arm 71a is connected in a freely rotatable manner, and the other of shafts 61 has both ends to which one end of second squeeze roller arm 71b is connected in a freely rotatable manner. On the other ends of squeeze roller arms 71a and 71b, respective squeeze rollers 7 are provided in a rotatable manner. With the above-described construction, each of squeeze rollers 7 moves centering on respective shafts 61 connected through respective squeeze roller arms 71a and 71b, to thereby open/close with each other. A mechanism for opening/closing squeeze rollers 7 will be discussed later.

Each of guide members 2a of folding guide 2 is provided with arm portion 2b fixed at support portion 62 which pivots shaft 61. According to the construction, folding guide 2 is interposed between film feed rollers 6 and squeeze rollers 7.

Referring to FIG. 4(b), two sheets of folding plates 5 are oppositely disposed to each other with folding guide 2 placed therebetween. Each of folding plates 5 is connected to air cylinder 51 which serves as an advance/retract driving unit. Each of folding plates 5 moves, by means of air cylinder 51, in synchronization with the position in which folding plates 5 are advanced into folding guide 2 and get closer to each other and in synchronization with the position in which folding plates 5 are retracted from the inside of folding guide 2 and spaced apart from each other. Each of folding plates 5 has oblique side 5a which gets closer to the center line of the pass route for tubular film 20 toward the feed direction of tubular film 20, that is, in the direction from the top towards the bottom of the vertical filling and packing machine.

Next, a mechanism for opening/closing squeeze rollers 7 will be explained. FIG. 5 is a view showing a squeeze roller opening/closing mechanism. FIG. 5(a) illustrates the state in which squeeze rollers are opened, and FIG. 5(b) illustrates the state in which squeeze rollers are closed. FIG. 5(c) is a right side elevation of the squeeze roller opening/closing mechanism shown in FIG. 5(b). FIG. 5(d) is a plane view illustrating the squeeze roller opening/closing mechanism shown in FIG. 5(b).

The squeeze roller opening/closing mechanism according to the embodiment of the present invention, includes first arms 30 each of which has one end connected in a rotatable manner to respective first squeeze roller arms 71a provided on opposing sides of folding guide 2, and second arm 31 having one end connected in a rotatable manner to connection member 32 which interconnects second squeeze roller arms 71a provided on opposing sides of folding guide 2.

Each of first arms 30 has the other end connected in a rotatable manner in the vicinity of the ends of crank 38 disposed on both ends of rotatable shaft 33. Ends of crank 38 are eccentric from the center of rotatable shaft 33.

On a near center portion of rotatable shaft 33, there is provided eccentric member 31a which has a circular outer circumference and which is fixed at rotatable shaft 33 in a state in which eccentric member 31a is eccentric from the center of rotatable shaft 33. A circular inner circumference is formed on the other end of second arm, wherein the circular inner circumference has a diameter substantially equal to that of the outer circumference of eccentric member 31a and is supported in a rotatable manner at the outer circumference of eccentric member 31a.

Between one end of rotatable shaft 33 and eccentric member 31a, there is provided pulley 34 which is coaxially connected to rotatable shaft 33. Above pulley 34, there is provided pulley 35 which is driven by motor 37. Pulleys 34 and 35 are wound with belt 36. Those pulleys 34 and 35, belt 36 and motor 37 constitute a driving unit for driving rotatable shaft 33. When pulley 35 is driven and rotates by motor 37, the driving force generated from pulley 35 is transmitted to pulley 34 through belt 36, thereby rotating rotatable shaft 33.

Next, operation of the squeeze roller opening/closing mechanism will be explained.

When rotatable shaft 33 is located at a first rotating position shown in FIG. 5(a), ends of crank 38 are positioned left of the center of rotatable shaft 33, and first squeeze roller arm 71a connected to crank 38 via first arm 30 is pushed to a position in which it gets farther away from rotatable shaft 33. In the meantime, the center of eccentric member 31a is positioned right of the center of rotatable shaft 33, and second squeeze roller arm 71b connected to eccentric member 31a via second arm 31 is pulled to a position in which it gets closer to rotatable shaft 33. Resultantly, squeeze rollers 7 disposed on respective ends of squeeze roller arms 71a and 71b are spaced apart from each other.

In the state described above, the ends of crank 38 move right of the center of rotatable shaft 33, and the center of eccentric member 31a moves left of the center of rotatable shaft 33, when motor 37 is driven to rotate pulley 34 in the direction of the arrow shown in FIG. 5(a). Accordingly, first squeeze roller arm 71a moves along the direction of getting closer to rotatable shaft 33 and second squeeze roller arm 71b moves along the direction of getting farther from rotatable shaft 33.

When rotatable shaft 33 is located at a second rotating position after completing a semi circular rotation in the state shown in FIG. 5(a), first squeeze roller arm 71a is pulled toward the position of getting closer to rotatable shaft 33 through first arm 30 and second squeeze roller arm 71b is pushed toward the position of getting farther from rotatable shaft 33 through second arm 31, to thereby make first and second squeeze roller arms 71a and 71b closest to each other, as shown in FIG. 5(b). Here, squeeze rollers 7 are kept in pressure contact with each other on center line C of the pass route for tubular film 20.

According to the squeeze roller opening/closing mechanism of the embodiment of the present invention, squeeze rollers 7 are kept in pressure contact with each other on center line C of the pass route for tubular film 20 when the squeeze roller opening/closing mechanism is closed. This allows squeeze rollers 7 to tightly squeeze tubular film 20 placed therebetween. Therefore, even in cases where opposing sides of tubular film 20 are folded inwardly or in cases where tubular film 20 is filled with a filling material having a high viscosity, the filling material can be easily divided in the inside of tubular film 20.

If tubular film 20 is squeezed by squeeze rollers 7 in the state where the holding portion formed by the pair of squeeze rollers deviates from center line C of the pass route for tubular film 20, opposing sides of tubular film 20 flattened by squeeze rollers 7 will deviate from each other. This may cause wrinkle generation on tubular film 20 when the film is heat sealed by sealing device 8. However, in the embodiment of the present invention, since tubular film 20 is kept between the pair of squeeze rollers 7 on center line C of the pass route for tubular film 20, opposing sides of tubular film 20 flattened by the pair of squeeze rollers 7 are prevented from deviating from each other during squeezing operation of squeeze rollers 7, and wrinkle generation on tubular film 20 is prevented while heat sealing is being performed thereafter on tubular film 20 by sealing device 8.

Now, construction of K-shaped sealing bar 80 in sealing device 8 will be explained with reference to FIG. 6. FIG. 6(a) is a front view of K-shaped sealing bar 80, and FIG. 6(b) is a right elevation of K-shaped sealing bar 80.

Lateral sealing portion 81 is formed on the pressure surface of K-shaped sealing bar 80 which presses empty portion 20b of tubular film 20, such that lateral sealing portion 81 extends in a lateral direction of tubular film 20 and heat seals the empty portion 20b in a lateral direction. In addition, a pair of oblique sealing portions 82 is formed into an L-shape opened in the angle of 90 degrees, above and below lateral sealing portion 81, respectively. Lateral sealing portion 81 and oblique sealing portion 82 constitute a K-shaped heat sealing unit.

Now, referring to FIGS. 7 to 9, the filling and packing operation of the vertical filling and packing machine of the embodiment of the present invention will be explained. FIGS. 7 and 8 illustrate the filling and packing operation of the vertical filling and packing machine of the embodiment of the present invention. FIG. 9 is a timing chart showing the filling and packing operation conducted by the vertical filling and packing machine of the embodiment of the present invention.

As an initial process, folding plates 5, squeeze rollers 5 and K-shaped sealing bars 80 of sealing device 8 are kept open. Here, the part of tubular film 20 which is heat sealed by sealing device 8 in the previous step is interposed between K-shaped sealing bars 80. In addition, tubular film 20 contains part of the filling material introduced through injection pipe 1 in the previous step.

FIG. 7(a) illustrates folding plates 5 at an opened state, in which folding plates 5 have completely retracted to the outside of folding guide 2. However, this may be desirable if parts of folding plates 5 have advanced into folding guide 2 in the state where folding plates are opened.

Subsequently, film feed rollers 6 rotate to commence downward feeding of tubular film 20 while filling tubular film 20 with a predetermined amount of filling material through injection pipe 1. Further, air cylinder 51 (refer to FIG. 4) and motor 37 (refer to FIG. 5) are driven to close folding plates 5 and squeeze rollers 7 as shown in FIG. 7(b).

When tubular film 20 is filled with a filling material, tension is generated on tubular film 20 due to the weight thereof, thereby pushing tubular film 20 into folding guide 2. Tubular film 20 with thus-generated tension is carried downward in a state where folding plates 5 are fitted to opposite sides thereof, such that V-shaped folded portions are formed in tubular film 20 in the region lower than folding plates 5. Meanwhile, each folding plate 5 has oblique side 5a which gets closer to folding guide 2 toward the feed direction of tubular film 20, that is, the direction from the top towards the bottom of the vertical filling and packing machine. Tubular film 20 is smoothly and gradually folded into a V-shape along oblique side 5a.

Squeeze rollers 7 divide the filling material in tubular film 20 by squeezing the V-shaped folded portion of tubular film 20, to form empty portion 20b where no filling material exists in tubular film 20, as shown in FIG. 7(c).

When a predetermined length of tubular film 20 is fed downward, the feed operation of tubular film 20 by film feed rollers 6 is stopped. Then, as shown in FIG. 7(d), K-shaped sealing bars 80 of sealing device 8 are closed, and empty portion 20b is heated and pressed by lateral sealing portions 81 and oblique sealing portions 82 of K-shaped sealing bars 80, thereby heat sealing the unheated area of empty portion 20b. At least one of K-shaped sealing bars 80 has a built-in heater (not shown) for heating empty portion 20b.

After finishing heat sealing by K-shaped sealing bars 80 has been completed, K-shaped sealing bars 80 are opened as shown in FIG. 8(e). A lateral sealing operation is performed on empty portion 20b by lateral sealing portion 81 and concurrently an oblique sealing process is performed above and below empty portion 20b by oblique sealing portion 82.

Subsequently, air cylinder 51 (refer to FIG. 4), and motor 37 (refer to FIG. 5) are driven to open folding plates 5 and squeeze rollers 7 as shown in FIG. 8(f).

Successively, as shown in FIG. 8(g), film feed rollers 6 rotate to feed tubular film 20 downwardly until the lateral seal formed in empty portion 20b reaches the height of cool cutting device 9.

Finally, as shown in FIG. 8(h), cooling bar 90 and cooling bar support 91 of cool cutting device 9 are closed so as to cool the lateral seal of empty portion 20b placed between cooling bars 90. Subsequently, cutter blade 90a that is received in the inside of cooling bar 90 protrudes toward cooling bar support 91 and cuts the lateral seal of empty portion 20b in a lateral direction. Consequently, gusset pouch G containing a filler material is dropped down from cool cutting device 9. Gusset pouches are consecutively manufactured by repeating the processes described above.

According to the vertical filling and packing machine of the embodiment of the present invention, folding guide 2 and folding plates 5 are disposed outside tubular film 20. This serves to prevent the filling material introduced in tubular film 20 through injection pipe 1 from sticking to folding guide 2 or folding plates 5, which may otherwise take place in a conventional structure in which a guide arm is arranged within a tubular film. Such an advantage of the present invention prevents deterioration of the fluidity of the filling material in tubular film 20 which would happen if the filling material adhered to the folding guide or the folding plates. This allows for ease of maintenance of the filling and packing machine by eliminating the necessity of periodically cleaning the folding guide or folding plates.

FIG. 10 is a perspective view showing a gusset pouch manufactured by the vertical filling and packing machine of the embodiment of the present invention. Gusset pouch G manufactured by the vertical filling and packing machine of the embodiment of the present invention has a corner which is kept free of filling material by oblique seal G1 formed in a gusset portion. This prevents the gusset portion from being swelled by the filling material introduced in the gusset portion. This makes it easy for the shape of the gusset pouch to be maintained which is formed into a rectangular shape through frame F as shown in FIG. 11, and hence serves to allow gusset pouches to be efficiently used when shipped in boxes or when displayed in shops.

While the invention has been illustrated and described as embodied in a vertical filling and packing machine in which sealing device 8 performs only a heat sealing operation onto tubular film 20, and the cutting of the portion which is heat sealed by sealing device 8 is carried out by cool cutting device 9 disposed below sealing device 8, however, configuration of sealing device 8 applicable to the vertical filling and packing machine is not limited to the details shown but can be modified in which sealing device 8 has the function of cool cutting device 9 for cutting a heat sealed part. In this case, a cutter blade is provided in an advancing/retracting manner in lateral sealing portion 81 of one of two K-shaped sealing bars 80, and a concave shape is formed in lateral sealing portion 81 of the other of two K-shaped sealing bars 80 such that the concave serves as a base for a cutter when the cutter blade is protruded. By this configuration, the cutter blade protrudes and cuts tubular film 20 while the film is pressed by two K-shaped seal bars 80 after the heat sealing process has been completed.

FIG. 12 is a view showing another construction of a K-shaped sealing bar. On a pressure surface of K-shaped sealing bar 80, there is a provided lateral sealing portion 81 which extends in a lateral direction of tubular film 20 and heat seals empty portion 20b in a lateral direction. In addition, above and below lateral sealing portion 81, there are provided a pair of oblique sealing portions 82 extending in an angle of approximately 45 degrees with respect to lateral sealing portion 81. Oblique sealing portions 82 formed at opposing sides of lateral sealing portion 81 are spaced apart from each other. Lateral sealing portion 81 and oblique sealing portions 82 constitute an approximately K-shaped heat sealing unit.

FIG. 13 is a perspective view of a gusset pouch manufactured by the K-shaped sealing bar shown in FIG. 12. The gusset pouch shown in FIG. 13 has a lateral width wider than that of the gusset pouch shown in FIG. 10. It is possible to form oblique seals G1 in corners of gusset pouch G having a wide lateral width by using K-shaped sealing bar 80 in which oblique sealing portions are spaced apart from each other. The corners of the gusset pouch shown in FIG. 13 are also kept free of filling material owing to oblique seals G1 formed in gussets thereof. This prevents gussets from being swelled by the filling material introduced in gussets.