JP2682412B2 - Square bottom bag making machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a square bag making machine for continuously forming paper bags such as shopping bags.

[0002]

2. Description of the Related Art A square bottom bag making machine of this type is a paper tube for a paper bag, which is formed by cutting a long tubular paper tube, which is folded in an M shape on both sides, into a predetermined size before the bottom is folded. 1 or a pre-cut sheet having a predetermined size is conveyed one by one by a conveying device intermittently in sequence, and both sides of the sheet M are conveyed during the conveyance.
The paper tube 1 is folded into a letter shape, folded in half, and the outer edge thereof is glued to form the paper tube 1 having front and rear openings. After this, the figure
As shown in FIG. 17 (A), the folding lines 2 and the folding lines 3 of the folding flaps 1A and 1B are engraved in parallel with each other near the bottom of the bag of the paper tube 1, and then the folding flaps 1A and 1B are folded inward to form a paper bag. To form the bottom of the corner. Then, as shown in FIG. 18, a square bottom bag making machine for forming a square bottom portion of such a paper bag is configured with a catch claw 5 provided on a bottom folding drum 4 for bottom-folding the bottom portion of the paper tube 1 with a catch cylinder 5. 1, the back side folding flap 1A is clamped, and the paper cylinder 1 is rotatably transported as the bottom folding drum 4 rotates. In this case, the paper cylinder 1 conveyed by the bottom folding drum 4 is
As shown in 17 (B), only the front folding flap 1B is folded back from the folding line 3 and the front and back flaps 1A and 1B are folded.
Are developed in a plane along the outer periphery of the bottom folding drum 4, and in this state, they are transferred together with the bottom folding drum 4. Then, while the paper tube 1 is being transferred, the flaps 1A and 1B are glued to each other by the gluing roller (not shown) provided along with the bottom folding drum 4, and thereafter, as shown in FIG. Two pushing blades 6, 6 that rotate in synchronization with the rotation
By A, the folding line 2 portion of each flap 1A, 1B is pushed into the groove portion 4A provided in the bottom folding drum 4. The flaps 1A and 1B are folded inward, respectively, before and after the folding line 2 pushed into the groove 4A by the openable / closable holding claws 7 provided inside the groove 4A. The flaps 1A and 1B folded back in this manner are pressed against the bottom folding drum 4 by a press roller or the like to attach the flaps 1A and 1B, and as shown in FIG. 17 (C) and FIG. It is configured to form the corner bottom portion 8A.

[0003]

The bottom folding method in the conventional square-bottom bag-making machine is such that when the square-bottom portion 8A of the paper bag 8 is formed, it is flatly spread along the outer periphery of the bottom-folding drum 4. The folding lines 2 of the front and back folding flaps 1A and 1B are pushed into the grooves 4A provided in the bottom folding drum 4 by the pushing blades 6 and 6A, and the folding lines 2 are opened and closed by the holding claws 7 provided in the grooves 4A. The front and rear flaps 1A, 1B are folded back inward and attached to each other, so that when the folding line 2 of the back side folding flap 1A on the tip side is pinched by the holding claws 7, the back side folding flap 1A Fold line 2
Is the edge of the square-bottom part 2, so there is no problem,
When the front side folding flap 1B folded back inside out is pinched by the holding claws 7, the front and back side paper of the paper tube 1 is bitten and is bitten, so a biting mark remains at the bottom of the paper tube 1 and is shown in FIG. As described above, it appears as streaks 9 in the finished paper bag 8 and is unsightly in terms of appearance design, and is not suitable for a paper bag in which importance is attached to the appearance design such as a gift. Therefore, in order to make a paper bag having no streaks by using the conventional square bottom bag making machine, for example, the bottom folding drum 4 holds only the folding line 2 portion of the back folding flap 1A which is the edge portion of the square bottom portion 2. It is folded back by the claw 7, and thus the back side folding flap 1
It is conceivable that the paper cylinder 1 in which A is folded is conveyed to a folder having a structure different from that of the bottom folding drum 4, and the front side folding flap 1B is folded alone. Not only does the device itself increase in size due to the fact that the folding machines for the front folding flaps 1B are connected in series, but the folding process is complicated by performing the folding of the front and back folding flaps 1A and 1B in separate steps. While it can form a paper bag without streaks,
It has a problem of causing a decrease in productivity.

Therefore, the present invention provides a square-bottom bag making machine capable of folding the front and back folding flaps substantially simultaneously by the bottom folding drum to miniaturize the apparatus itself and efficiently forming a streak-free paper bag. With the goal.

[0005]

SUMMARY OF THE INVENTION A square bottom bag making machine according to the present invention comprises a bottom opening device for adsorbing a front side folding flap of a paper tube to open the bag bottom, and a catch for holding a back side folding flap of the paper tube. A bottom folding drum that has a claw and that rotationally transports the paper cylinder by rotation, a flap folding device that is provided near the outer circumference of the bottom folding drum, and reverses the folding flap on the front side from the folding line of the paper cylinder, A gluing device for gluing the front and back folding flaps of the paper cylinder, a groove portion provided on the bottom folding drum corresponding to the folding line portion of the back folding flap, and the front and rear folding lines of the back folding flap provided in the groove portion. A holding claw that bites in, and an opening and closing claw that is placed between the front surface of the paper tube and the front folding flap and that bites before and after the folding line of the front folding flap, corresponding to the folding line portion of the front folding flap, Opening and closing claw and holding Wherein the front and rear push blade lure fold lines, those having a bag bottom folding device folding the sides each folding flap caused by the opening and closing of the closing pawl and clamping claws inwardly.

[0006]

According to the present invention, the front folding flap of the paper tube is opened by the bottom opening device to open the bag bottom of the paper tube, and the catch tab provided on the bottom folding drum holds the back folding flap of the paper tube. Almost at the same time, the opening and closing claws project to the inside of the surface of the paper bag, and the front folding flap of the paper cylinder that is rotatably transferred by the rotation of the bottom folding drum is folded back from the folding line to the inside by the flap folding device, and along the bottom folding drum. Since the front and back folding flaps are unfolded, the opening and closing claw is arranged between the front surface paper and the front folding flap. After that, the paper cylinder in which the front and back folding flaps are spread along the bottom folding drum is transported by the rotation of the bottom folding drum, and the front and back folding flaps are glued by the gluing device during the transportation. The pushing blade bites into the folding line portions of the front and back folding flaps glued in this way, and the folding line portion is guided between the holding claws and the opening / closing claws provided on the bottom folding drum. By closing, the folding line portions of the front and back folding flaps are bitten by and rise up, and are folded inward by the bag bottom folding device, whereby the corner bottom portion of the paper bag is formed.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 16 show an embodiment of the present invention,
The same parts as those in the conventional example will be described using the same reference numerals.
The square-bottom bag making machine of the present invention continuously conveys the paper bag constituent paper that has been cut into a predetermined size in the previous step at intervals, and folds the paper bag constituent paper into two by a folding device (not shown) during the conveyance. Then, the side end edges are folded in such a manner that the side edges of the paper cylinder 1 are folded so that both side portions thereof have an M shape, and the paper tube 1 having front and rear openings is formed. Then, the paper tube 1 thus formed is continuously supplied by the supply device A as shown in the schematic explanatory view of FIG. On the terminal side of the supply device A, a crease creasing device B for making a crease near the bag mouth of the paper cylinder 1 which becomes the bag mouth of the finished paper bag 8 and a corner bottom of the finished paper bag 8 are folded near the bag bottom. A bottom folding creasing device C for making an eye and a bottom opening device D for adsorbing the bag bottom side to open the bag bottom and a bottom folding drum 4 for sandwiching the bag bottom side of the paper tube 1 to convey the paper tube 1 in rotation. The front folding flaps 1B are folded back from the folding line 3 formed by the bottom folding creasing device C to the inside of the paper tube 1 on the outer periphery of the bottom folding drum 4, and the front and back folding flaps 1A. , 1B are spread flatly along the bottom folding drum 4, a flap folding device E, a gluing device F for gluing the front and back folding flaps 1A, 1B, and a bag bottom for sticking the folding flaps 1A, 1B. The folding devices G are arranged in parallel.

More specifically, the supply device A is shown in FIG.
As shown in the figure, the driving sprocket 11 and the driven sprocket
And a pair of left and right endless conveyor chains 13 provided so as to bridge the paper cylinder 1 with the feed claws 14 attached to the conveyor chain 13 so that the bottom of the bag is oriented in the conveying direction. It is transported to the attaching, bottom folding and sticking processes.
Between the paper tube feeder A and the crease creasing device B, as shown in FIG.
As shown by, a pair of upper and lower press rollers 15 are arranged,
The press rollers 15 are rotated in opposite directions by a driving device (not shown), and the paper tube 1 is sandwiched so that both sides of the paper tube 1 are pressed and transferred to the bottom folding creasing device C in the next step. doing.

As shown in FIG. 2, the orbital creasing device B has an upper rotary shaft 21 having a flat plate-shaped creasing blade 20 and a lower rotary shaft having a receiving roller 22 for the creasing blade 20. As shown in FIG. 3, the creasing blade 20 is fixed to a pair of mounting plates 24 fixed to the upper rotary shaft 21 by screws, and is provided on one side of the lower rotary shaft 23. The transmission gear 25A that meshes with the drive gear 25 that branches and transmits the rotation from the drive source is fixed, and the lower rotary shaft 23 is rotationally driven through these gears 25, 25A.
The rotation is transmitted to the upper rotating shaft 21 via a plurality of relay gears 26 and 26A fixed to the other side of the lower rotating shaft 23 and the upper rotating shaft 21.
By rotating the upper rotary shaft 21 in the opposite direction to the lower rotary shaft 24, the creasing blade 20 is pressed against the bottom of the paper cylinder 1 sent from the press roller 15 to close the mouth. Make a fold 27 at the edge. And each rotary shaft 21,
By rotating 23, the paper tube 1 is transferred to the bottom folding creasing device C in the next step.

The bottom folding creasing device C, as shown in FIG.
The structure is substantially the same as that of the mouth folding creasing device B. In this bottom folding creasing device C, an upper rotary shaft 31 having two flat plate creasing blades 30 and 30A and the creasing blade 30 thereof are provided. , 30A, and a lower rotary shaft 33 having receiving rollers 32 of 30A, and a bridge plate 34 is provided between the mouth folding creasing device B and the bottom folding creasing device C. The bottom folding creasing device C is driven by rotating the lower rotating shaft 33 by a drive gear and a relay gear (not shown) fixed to the upper rotating shaft 31 and the lower rotating shaft 33 as in the case of the mouth folding creasing device B described above. By driving and transmitting the rotation to the upper rotation shaft 31, the creasing blades 30 and 30A are pressed against the bag bottom, which is the front side in the transport direction of the paper tube 1, to fold the bottom folding. Two parallel lines, line 2 and folded line 3, are engraved. In this case, as for the folding line 2 and the folding line 3, as shown in FIG. 4, the interval S from the front end side of the paper tube 1 to the folding line 2 becomes the length of the front and back folding flaps 1A and 1B, respectively. 1
When folding A and 1B, these folding flaps 1A,
The spacing S is set to be longer than half the opening width of the paper tube 1 so that 1B overlaps with each other. The space S1 between the folding line 2 and the folding line 3, that is, the space between the creasing blades 30 and 30A is set to be approximately half the opening width of the paper tube 1. In this case, since the creasing blades 30 and 30A of the bottom folding creasing device C are fixed to the recess 35A formed by cutting out the outer periphery of the mounting plate 35 in order to accommodate various bag mouth sizes, one of them The scoring blade 30 is fixedly fixed, but the other scoring blade 30A is movably fixed in the mounting position in the recess 35A as shown by the chain double-dashed line in FIG. Then, in this manner, the paper tube 1 containing the folding line 2 and the folding line 3 is transferred to the bottom opening device D by the rotation of the rotary shafts 31 and 33.

The bottom opening device D is, as shown in FIGS. 1 and 5, fixed to the upper rotary shaft 40 by being located on both sides of the rotary arc plate 41 fixed to the upper rotary shaft 40. And a suction pad 43 fixedly mounted on the rotating arc plate 41 so as to face an opening 43A formed in the outer peripheral surface of the pressing plate 42 and the rotating arc plate 41, and the lower rotation paired with the rotating arc plate 41 in the vertical direction. axis
45, which is connected to the suction pad 43 by a negative pressure generating device such as a vacuum pump (not shown) so that the paper cylinder 1
The front folding flap 1B is sucked, and the front folding flap 1B of the paper cylinder 1 is sucked along the rotation locus of the suction pad 43 attached to the rotating arc plate 41. Then, almost at the same time as this, the back side folding flap 1 of the paper cylinder 1 whose bag bottom is opened by the catch claws 5 provided on the bottom folding drum 4 which is arranged close to the bottom opening device D.
Hold the tip of A and rotate the upper rotary shaft 40 and the bottom folding drum 4 in opposite directions to open the bag bottom of the paper cylinder 1.

As shown in FIG. 5, a pair of left and right guide plates 50 serving as the flap folding device E are located on both sides of the bag opening opened by the bottom opening device D, and are horizontally provided above the bottom folding drum 4. It is fixed to a mounting rod 51 that is substantially horizontal via a mounting arm 52. The left and right guide plates 50 are flat plate portions 53.
And a lower portion 54 that extends downward from both side ends of the flat plate portion 53. Further, one end side of the flat plate portion 53 (bottom opening device D side) is formed with an inclined portion 54A that gradually increases toward the outer edge portion, and the multi-end side of the flat plate portion 53 contacts the outer peripheral surface of the bottom folding drum 4. It is fixed to the mounting arm 52. Further, between the guide plates 50, a linear member 56 for pressing the central portion of the paper cylinder 1 against the outer peripheral surface of the bottom folding drum 4 is fixed to the mounting rod 51 via a mounting arm 52A.
The paper cylinder 1 rotatably conveyed by the bottom folding drum 4 is guided between each guide plate 50 and the bottom folding drum 4, and the front folding flap 1B sucked by the bottom opening device D is guided by each guide plate 50. The bottom folding drum 4 is pressed against the flat plate portion 53 and the front folding flap 1B is turned upside down from the folding line 3 and folded back. That is, the back flap 1
By folding back only the front side folding flap 1B while leaving A, the front and back folding flaps 1A and 1B are developed in a plane along the outer circumference of the bottom folding drum 4. In this way, the paper folding cylinder 1 in which the front and rear folding flaps 1A and 1B are developed by the flap folding device E is conveyed in unison with the rotation of the bottom folding drum 4. At this time, the press roller 57 and the bottom folding drum 4 sandwich both sides of the folding flaps 1A and 1B to fold the folding flaps 1A and 1B into a flat shape, and the paper cylinder 1 is attached to the bottom folding drum 4. The paper cylinder 1 is prevented from rising and stably conveyed through a slight gap between the curved guide regulating plate 58 and the bottom folding drum 4.

As shown in FIG. 6, the gluing device F comprises a gluing roller 62 having a gluing portion 61 made of synthetic rubber or the like on a tank 60 for containing starch glue or a chemical gluing adhesive A.
And a relay roller 64 provided between the tank 60 and the gluing roller 62 so as to face the lower surface opening 63 of the tank 60,
The adhesive A in the tank 60 is attached to the gluing portion 61 of the gluing roller 62 via the relay roller 64, and is glued to the front and back folding flaps 1A by the rotation of the gluing roller 62. The gluing roller 62 is attached via an air cylinder 65, and when the bottom folding drum 4 does not have the paper cylinder 1 due to a paper jam or the like, the air cylinder 65 is driven to move the gluing roller 62 upward. The adhesion of glue to the bottom folding drum 4 is prevented. In the drawing, reference numeral 66 denotes a tray.

As shown in FIGS. 7 to 10, the bottom folding drum 4 is composed of an assembly of a plurality of divided drums 72 fixed to a mounting cylinder 71 fixed to a rotary shaft 70 at appropriate intervals. A groove portion 4A in which a catching claw 5 that holds the tip of the back side folding flap 1A of the paper tube 1 and a holding claw 7 that engages the front and back of the folding line 2 of the back side folding flap 1A are alternately arranged between the respective split drums 72. Are formed. The catch claw 5
As shown in FIG. 7, the front end portion is located at the central portion of the groove portion 4A and extends from the groove portion 4A to the outside of the outer periphery of the split drum 72. Hold the folding flap 1A. On the other hand, the holding claw 7
Is a fixing claw 73 fixed to the end of the groove 4A and this fixing claw.
73 and a movable claw 74 provided in the groove portion 4A facing each other,
By opening and closing the movable claw 74, the front and rear of the folding line 2 of the back folding flap 1A are held. Further, as shown in FIGS. 8 and 10, the attachment claw 5 is attached to the attachment cylinder 71 of the rotary shaft 70.
And the mounting brackets 76, 76A of the holding claw 7 are the mounting bolts 75.
Are mounted and fixed integrally by each of these mounting brackets
The catching claw 5 and the holding claw 7 are integrally fixed to shafts 77 and 77A that are rotatably supported by the 76 and 76A. And
Rotating rollers 81, 81A are provided at one end of the shafts 77, 77A of the catching claw 5 and the holding claw 7 via mounting arms 78, 78A,
The rotary rollers 81, 81A are located on the side of the bottom folding drum 4 and are rolled along a cam surface 80 fixed to the main body frame 79. Further, a clamp 82 is attached to the shaft 77, 77A,
82A is integrally fixed, and this clamp 82, 82A
L-shaped fixing metal fittings 83, 83A are fixedly attached to the mounting brackets 76, 76A facing each other, and the rotary rollers 81, 81A are cammed between the fixing metal fittings 83, 83A and the clamps 82, 82A. Rods 85 and 85A are provided, which have springs 84 and 84A that urge them to press against the surface 80. And the cam surface
When the rotating rollers 81 and 81A of the catching claw 5 and the holding claw 7 ride on the protruding portion (not shown) formed in 80, the rotating roller 8
The catching claw 5 and the holding claw 7 are configured to be opened and closed via the 1, 81A, the clamps 82, 82A, and the shafts 77, 77A.

As shown in FIGS. 11 to 13, a pair of opening / closing claws 90, 90A for engaging the front and rear of the folding line 2 of the front folding flap 1B are assembled on both sides of the bottom folding drum 4. These open / close claws 90 and 90A are both mounting brackets 9.
The mounting brackets 91 and 91A are fixed to the mounting brackets 1 and 91A, and the mounting brackets 91 and 91A are rotatably mounted by a shaft 92. One opening / closing claw is mounted by a spring 93 provided between the mounting brackets 91 and 91A.
90A is urged against the other opening / closing claw 90 side. Further, a shaft 94 is integrally fixed to an end portion of the one mounting bracket 91, and the shaft 94 is attached to the mounting cylinder 91.
It is slidably guided by the support bracket 95 fixed to 71 and the bottom folding drum 4. Further, a push-down lever 95 for rotating the opening and closing claws 90, 90A toward the bottom folding drum 4 side is integrally assembled and fixed to the shaft 94, and the body frame 79 corresponding to the shaft 94 is provided. A first cam 96 that is in contact with the outer end surface of the shaft 94 is positioned outside and fixed to both sides of the bottom folding drum 4, and the upper end of the first cam 96 is in contact with the tip of the push-down lever 95. The second cam 97 is fixed. Also, inside the cams 96 and 97, the opening and closing claws are provided.
A third cam 99 on which a rotating roller 98 mounted on a mounting bracket 91A of 90A rides is fixed. And the axis
94 is a spring arranged in a recess 94A formed on the multi-end side of the spring.
The pressing lever 95 is pressed against the first cam 96 by 93A, and the push-down lever 95 is moved to the second position by a spring 93B that is bridged between the mounting bracket 91 for assembling the fixed side opening / closing claw 90 and the supporting bracket 95. It is configured to be pressed against the cam 97.

On the front side of the bottom folding drum 4, as shown in FIG. 14, a rotary shaft 100 provided with two flat plate-like pushing blades 6 and 6A is horizontally installed, and by the rotation of the rotary shaft 100. The pushing blades 6 and 6A are pressed along the folding lines 2 of the front and back folding flaps 1A and 1B of the paper tube 1 conveyed by the bottom folding drum 4 to keep the folding line 2 portion open. It is guided in the held claw 7 and the opening / closing claws 90, 90A. Then, after opening the catching claw 5 that was gripping the back side folding flap 1A, the holding claw 7 and the opening / closing claw 901A are closed and the front and back folding flaps 1A and 1B are raised by biting the front and back of the folding line 2. It will be folded like this.

A bag bottom folding device G for folding the front and back folding flaps 1A and 1B raised by the pushing blades 6 and 6A inward is provided on a sprocket 105A in front of the bottom folding drum 4 as shown in FIG. A bottom folding rod 106 fixed to a pair of left and right chains 105 and a bottom folding plate 107 provided with a slight gap from the peripheral surface of the bottom folding drum 4 are provided.
The front folding flap 1B is folded inward by 6 and the back folding flap 1A is folded inward by a bottom folding plate 107. Then, as shown in FIG. 1, the front and back folding flaps 1A and 1B are folded inwardly by the first and bottom folding plates 106 and 107, and a rotary drive drum 108 and a plurality of guide rollers are provided below the bottom folding drum 4. The front and back folding flaps 1A and 1B, which are glued in the previous step, are attached by the two endless belts 110 and 110A which are laid across the 109. A part of the one endless belt 110A (shown by a chain line in the drawing) is pressed against the outer peripheral surface of the bottom folding drum 4. Then, the paper cylinder 1 conveyed by the bottom folding drum 4 is rotated by the bottom folding drum 4, and first, by the rotation of the chain 105, the bottom folding rod 10 attached to the chain 105.
6 rotates and hits the front folding flap 1B to fold it inward, and then the bottom folding drum 4 rotates to pass the standing back folding flap 1A through the gap between the bottom folding plate 107 and the bottom folding drum 4. It is folded inward and folded inward so as to be folded over the front folding flap 1B. And
In this manner, with the front and back folding flaps 1A and 1B folded, the paper cylinder 1 is sandwiched between the bottom folding drum 4 and the endless belt 110A, and the front and back folding flaps 1A and 1B are attached. It In this way, the paper cylinder 1 in which the front and back folding flaps 1A and 1B are folded is the bottom folding drum 4 and the endless belt 110.
After being transported to the rotary drive drum 108 by the rotary drive drum 108, the rotary transport drum 108 and the other endless belt 110A laid over the rotary transport drum 108 to the feed position H of the pressing device (not shown) in the next step. Front and back folding flaps 1A and 1B that have been conveyed and folded by the bag bottom folding device G
Is pressed to form the corner bottom portion 2A of the paper bag 8. The operation of the present invention configured as above will be described.

First, a paper cylinder 1 having both sides folded in an M shape by a folding machine (not shown) is conveyed to a pair of upper and lower press rollers 15 by a feed claw 14 attached to a conveyor chain 13, and the press rollers 15 convey the paper cylinder. Both sides of 1 are pressed, and the paper cylinder 1 is conveyed to the origami creasing apparatus B in a state of being folded flat. The paper cylinder 1 conveyed from the press roller 15 causes the creasing blade 20 provided on the upper rotation shaft 21 to be pressed against the rear bag mouth of the paper cylinder 1 by the rotation of the upper rotation shaft 21, and is used for folding. Crease 27 is engraved. Although not shown, the fold 27 at the bottom of the bag serves as a fold for inwardly folding the peripheral edge of the bag mouth in order to reinforce the bag mouth when attaching a handle or the like to the finished paper bag in a later step. Then, the rotary shafts 21 and 23 are rotated to rotate the paper cylinder 1.
Is transferred to the bottom folding creasing apparatus C in the next step. Here, similarly to the orbital creasing device B, the lower rotary shaft 33 is rotationally driven,
The creasing blades 30 and 30A are pressed against the bottom of the paper cylinder 1 on the rear side in the transport direction to engrave two parallel creases of a folding line 2 and a folding line 3 for bottom folding. . Thereafter, the paper tube 1 containing the folding line 2 and the folding line 3 is transferred to the bottom opening device D by the rotation of the rotary shafts 31 and 33, and the suction pad 43 sucks the front end side of the front surface of the paper tube 1. Then, the bag bottom of the paper tube 1 is opened along the rotation trajectory of the suction pad 43, and at the same time, the catching claws 5 provided on the bottom folding drum 4 arranged close to the bottom opening device D open the paper bottom of the bag. The front end of the cylinder 1 on the back surface side, that is, the back side folding flap 1A is held. On the other hand, each of the opening / closing claws 90, 90A is in the state where the shaft 94 fixed to the mounting bracket 91 of the opening / closing claw 90 is in contact with the first cam 96 by the spring 93A until the catching claw 5 holds the paper cylinder 1. Rotating rollers 98 provided on the mounting bracket 91A of the opening / closing claw 90A, which is located on the outside of both sides of the folding drum 4 and whose movable side has the respective opening / closing claws 90, 90A, rides on the third cam 98 and the respective mounting brackets 91A. , 91A between the opening and closing claws 90 by the biasing force of the spring 93,
90A is held open. And the catch claw 5
The shaft 94 is pushed inward by the protrusion (not shown) of the first cam 96 almost at the same time when the paper tube 1 is held by the spring 93.
Each of the opening / closing claws 90, 90A protrudes inwardly of A, that is, above the paper tube 1 held by the catch claws 5. On the other hand, the push-down lever 95 fixed to the shaft 94 is pressed against the second cam 97 by the spring 93B. However, after the opening / closing claws 90 and 90A project above the paper tube 1 in the open state, The push-down lever 95 falls into the depressed portion 97A of the second cam 97, and the shaft 94 moves to the position shown in FIG.
As shown in FIG. 4, the opening / closing claws 90, 90A rotate downward as the shaft 94 rotates and come into contact with the front surface of the paper tube 1. At this time, the opening / closing claws 90, 90A of the fixed side are located in front of the folding line 2 with the opening / closing claw 90 on the fixed side thereof being close to the folding line 2 of the front folding flap 1B.
Is located behind the folding line 2 of the front folding flap 1B.
In this way, the open / close claws 9 in the open state are provided on the front surface of the front surface of the paper tube 1.
0 and 90A stand by before and after the folding line 2 of the front folding flap 1B. Then, by rotating the upper rotary shaft 40 and the bottom folding drum 4 in mutually opposite directions, the bag bottom of the paper cylinder 1 is opened. In this way, the paper cylinder 1 having the opening at the bottom of the bag is guided by the rotation of the bottom folding drum 4 into the space between the guide plates 50 and the bottom folding drum 4 that form the flap folding device E at the bottom portion of the bag. Only the front folding flap 1B has the above-mentioned opening / closing claws 90,
It is folded back to the front side of the paper tube 1 via 90A, and each opening / closing claw 9
0 and 90A are disposed between the front surface of the paper tube 1 and the front folding flap 1B, and the front and back folding flaps 1A of the paper tube 1 are
1B is flatly developed along the outer periphery of the bottom folding drum 4. Then, the paper cylinder 1 is conveyed by the rotation of the bottom folding drum 4, and is glued to the front and back folding flaps 1A and 1B by the glue roller 62 during the transportation. After the gluing process is completed, the folding shafts 2 of the front and back folding flaps 1A, 1B of the paper tube 1 are rotated by the rotation of the rotary shaft 100 of the pushing blades 6, 6A.
The push-in blades 6 and 6A are bitten in along with, and the fold line 2 is guided between the holding claw 7 and the open / close claws 90 and 90A which are held in the open state. Then, the catching claw 5 moves upward along a protruding portion (not shown) formed on the cam surface 80 by the rotation roller 81 thereof, and moves away from the back side folding flap 1A that has been gripped up to that time, and the holding claw 7 Of the rotary roller 81A of the opening and closing claws 90, 90A of the third cam 99.
It moves to the lower part along the recessed part 99A, and the holding claw 7 and the opening / closing claws 90, 90A are closed by the urging force of the respective springs 84A, 93, whereby the back side folding flaps 1A, 1
The front and back folding flaps 1A and 1B are folded inward by biting the front and rear of the folding line 2 of B. In the paper cylinder 1 in which the front and back folding flaps 1A and 1B are folded, the bottom folding rod 106 first folds the front folding flap 1B inward by the rotation of the chain 105, and then the bottom folding drum 4 conveys the back folding flap 1B. 1A for bottom folding drum 4 and bottom folding plate 10
The back folding flap 1A is folded over the front folding flap 1B by passing it between the front folding flap 1B and the front folding flap 1B. After that, by sandwiching the paper tube 1 between the endless belt 110 and the endless belt 110 spanning the plurality of guide rollers 109, the folding flaps 1A and 1B on the front and back sides are overlapped and the paper bag 8 is rotated. The driving drum 93 and the endless belt 110A convey the sheet to a feeding position H of a pressing device (not shown) for the next step, and finally press the front and back folding flaps 1A and 1B to press the corner bottom 2A of the paper bag 8. Mold.

As described above, in this embodiment,
Not only the back side flap 1A but also the front side flap 1B
By sandwiching the folding line 2 portion of the bottom folding drum 4 with the sandwiching claw 7 of the bottom folding drum 4, the bite mark remained as a streak in the finished paper bag 8, but the present invention is not limited to the edge portion of the corner bottom portion 8A. The back side folding flap 1A is sandwiched and folded by the holding claws 7 as in the conventional case, but the front side folding flap 1B is an opening / closing claw 90, 90A arranged between the surface paper of the paper tube 1 and the front side folding flap 1B.
Unlike the conventional case, by folding by opening and closing, the surface paper of the paper tube 1 is not bitten, so the line that becomes the bite mark is eliminated, and there is no line as shown in FIG. An excellent paper bag 8 can be continuously molded. Moreover, according to the present invention, by assembling the holding claws 7 for folding the front and back folding flaps 1A, 1B and the opening / closing claws 90, 90A to the bottom folding drum 4, the device itself can be downsized and the bottom folding drum 4 can be made smaller. By opening / closing the assembled holding claw 7 and the opening / closing claws 90, 90A, the front and back folding flaps 1A, 1B can be folded almost at the same time, so that the bottom folding drum 4 can efficiently form a paper bag 8 having no streaks. , Can increase productivity.

The present invention is not limited to the above-mentioned embodiment, but various modifications can be made within the scope of the gist of the present invention. For example, the structure of the gluing device, the bottom opening device, the transport device, and the like, the driving means thereof, and the opening / closing means of the holding claws and the opening / closing claws are not limited to cams, but may be appropriately set such as cylinder devices. Further, in this embodiment, an example in which a paper tube is formed by folding one sheet of paper cut to a predetermined size before bottom folding is shown, but the present invention is not limited to this, and a continuous tubular paper tube is cut to a predetermined size. The paper cylinder may be molded by using In this case, a roll for winding the tubular paper cylinder may be provided, and a cutter device for cutting the tubular paper cylinder drawn from the roll into a predetermined size may be provided.

[0022]

The square bottom bag making machine of the present invention has a bottom opening device for adsorbing the front side folding flap of the paper tube to open the bag bottom, and a catching claw for holding the back side folding flap of the paper tube. And a bottom folding drum that rotates and transports the paper cylinder by rotation, a flap folding device that is provided near the outer circumference of the bottom folding drum, and that reverses the folding flap on the front side from the folding line of the paper cylinder, and the front and back sides of the paper cylinder. A gluing device for gluing each folding flap, a groove portion provided on the bottom folding drum corresponding to the folding line portion of the back folding flap, and a grip for engaging the front and rear folding lines of the back folding flap provided in the groove portion. A claw and an opening and closing claw which is arranged between the front surface of the paper cylinder and the front side folding flap and which engages the front and rear folding lines of the front side folding flap in correspondence with the folding line portion of the front side folding flap, the opening and closing claw and the On the holding claw A push blade lure write line, by having a flap attaching device for pasting wearing by Orikomin the sides each folding flap raised inside the opening and closing of the closing pawl and clamping claws, together with reduction in size of the apparatus itself,
It is possible to provide a square-bottom bag making machine that can fold the front and back folding flaps almost at the same time to efficiently form a streak-free paper bag.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the vicinity of the device with a streak.

FIG. 3 is a front view of the vicinity of the streak device.

FIG. 4 is an explanatory view showing a fold of the flap, and FIG.
Is a front view before the fold is made, and (B) is a front view after the fold is made.

FIG. 5 is a partially cutaway side view near the bottom opening device.

FIG. 6 is a sectional view showing the vicinity of the first gluing device.

FIG. 7 is a side view of the vicinity of the capturing claw.

FIG. 8 is a cross-sectional view of the vicinity of the capturing claw.

FIG. 9 is a side view of the vicinity of the holding claw.

FIG. 10 is a cross-sectional view of the vicinity of the holding claw.

FIG. 11 is a perspective view of the bottom folding drum showing the bottom folding state.

FIG. 12 is a sectional view showing the vicinity of the opening / closing claw.

FIG. 13 is a side view of the vicinity of the opening / closing claw.

FIG. 14 is a cross-sectional view near the pushing blade.

FIG. 15 is a side view of the bottom folding device showing a folded state of the flap.

FIG. 16 is a perspective view of the completed paper bag.

17A and 17B are explanatory views showing a folded state of a flap of a conventional example, FIG. 17A is a perspective view before folding, FIG. 17B is a perspective view showing a developed state of the flap, and FIG. Is.

FIG. 18 is a cross-sectional view showing a folded state of the flap.

FIG. 19 is a perspective view of the paper bag.

[Explanation of symbols]

 D Bottom opening device E Flap folding device F Gluing device G Bag bottom folding device 1 Paper cylinder 1A Back side folding flap 1B Front side folding flap 2 Folding line 3 Folding line 4 Bottom folding drum 4A Groove part 5 Capturing claw 6, 6A Pushing plate 7 Clamping Nail 8 Paper bag 90, 90A Open / close claw

Claims (1)

(57) [Claims] 1. A paper cylinder for a paper bag having front and back openings formed, which is located near the bottom of the paper cylinder and is formed on the front and back of the paper cylinder with the folding line and the folding line of the folding flap in parallel. The front folding flap is folded back from the folding line to the inside, and the front folding flap and the back folding flap are overlapped to fold each of the front folding flaps inward from the folding line to form a corner bottom portion of the paper bag. In a square-bottom bag making machine, a bottom opening device that adsorbs the front side folding flap of the paper tube to open the bag bottom, and a trapping claw that holds the back side folding flap of the paper tube and rotates the paper tube. A bottom folding drum that is rotatably transferred, a flap folding device that is provided in the vicinity of the outer periphery of the bottom folding drum and reverses the folding flap on the front side from the folding line, and a gluing device that glues each of the front and back folding flaps, Fold back Corresponding to the groove part provided in the bottom folding drum corresponding to the folding line part of the wrap, the holding claw provided in this groove part for biting the front and rear of the folding line of the back side folding flap, and the folding line part of the front side folding flap And an opening and closing claw that is arranged between the front surface of the paper tube and the front side folding flap and that bites the front and back of the folding line of the front side folding flap, and a pushing blade that invites the folding line of the front and back to the opening and closing claw and the holding claw. A square-bottom bag making machine comprising a bag-bottom folding device that folds inward and backward folding flaps caused by opening and closing the opening and closing claws and the holding claws.