Paper bag bottom folding equipment

Abstract

The present invention discloses a paper bag bottom folding device, which includes a machine body, a bag feeding device, and a bag bottom separating device. It is characterized in that the bag feeding device and the bag bottom separating device are arranged in parallel. A circulating and moving bag bottom expanding and folding device is provided on the machine body. The bag bottom expanding and folding device moves synchronously with the paper bag body on the bag feeding device. The bag bottom expanding and folding device includes a bottom plate and bag supporting rods that move towards each other. The bag supporting rods can move radially. A swinging folding plate is provided on the bag bottom expanding and folding device. With this structure of the present invention, during the transportation of the paper bag, the left and right sides of the bottom of the paper bag are folded, facilitating the subsequent folding of the upper and lower sides of the bottom of the paper bag. Its work is stable and reliable. After the left and right sides are folded, they are perpendicular to the upper and lower sides, ensuring that the bottom of the paper bag remains flat after bottom folding without wrinkles, and is particularly suitable for the bottom folding process of paper bags with a relatively small height.

Description

Technical Field

[0001] The present invention relates to a paper bag forming device, in particular to a bottom folding mechanism for a paper bag with a relatively small height. Background Art

[0002] Modern life requires a large number of paper bags, and a paper bag machine is a device for forming paper bags, which can complete processes such as making the bag body of the paper bag, folding the edges, and pasting the bottom. Especially for the bottom pasting process, it requires a very complex structure to achieve. By searching the Chinese patent database, a utility model patent with an authorized announcement number of CN207984140U and a name of a paper bag bottom folding device discloses the following content: A paper bag bottom folding device includes: a central rotating shaft, a large rotating wheel, a bottom folding mechanism, and a fixed frame; the central rotating shaft is of a cylindrical structure; the large rotating wheel is arranged on the central rotating shaft, and its center coincides with the center of the central rotating shaft; the number of the fixed frames is two, symmetrically arranged on the central rotating shaft; the bottom folding mechanism is symmetrically arranged on the two fixed frames with respect to the center of the large rotating wheel; the bottom folding mechanism is composed of a fixed block, slide rail one, slide rail two, movable slider one, movable slider two, telescopic rod one, telescopic rod two, paper clip one, and paper clip two; the bottom folding mechanism is arranged on the fixed frame, and the fixed block is fixed on the fixed frame; the slide rail one and the slide rail two are fixedly arranged side by side on the fixed block; the movable slider one is arranged on the slide rail one, and the movable slider two is arranged on the slide rail two; one end of the telescopic rod one is fixedly arranged on the movable slider one, and one end of the telescopic rod two is fixedly arranged on the movable slider two; the paper clip one is fixedly arranged at the other end of the telescopic rod one; the paper clip two is fixedly arranged at the other end of the telescopic rod two; the mechanism realizes the movement of the system components through integrated control. And the working principle is disclosed: A large rotating wheel and a fixed frame are installed on the central rotating shaft. Through the rotation of the central rotating shaft, the large rotating wheel lifts the paper bag. At this time, the bottom folding mechanism fixedly arranged on the fixed frame starts to operate. Through the integrated controller, the movable slider one slides downward on the slide rail one, the movable slider two slides downward on the slide rail two, the telescopic rod one and the telescopic rod two extend, and the paper clip displaces in the up, down, front, and back directions to realize the bottom folding work of the paper bag. For a paper bag bottom folding device with this structure, when folding the bottom, only the upper and lower sides of the bottom of the paper bag need to be folded, and the left and right sides of the bottom of the paper bag do not need to be folded. The reason is that the height of the paper bag processed by it is relatively large. After the paper clip clamps and moves the upper and lower sides for folding, the left and right sides are naturally perpendicular to the upper and lower sides. However, when the height of the paper bag is less than 40 mm, with the above-mentioned bottom folding mechanism, when the paper clip clamps the upper and lower sides and folds them, it is very easy for the left and right sides not to be perpendicular to the upper and lower sides, resulting in wrinkles on the bottom of the paper bag after folding, and the bottom of the produced paper bag is not flat. The above-mentioned height of the paper bag refers to the height of the paper bag when it is placed flat. Summary of the Invention

[0003] In view of the shortcomings of the background technology, the technical problem to be solved by the present invention is to provide a paper bag bottom folding device that can fold the left and right sides of the paper bag bottom so that the paper bag is wrinkle-free and flat after the bottom is folded.

[0004] To this end, the present invention is implemented by adopting the following technical scheme: a paper bag bottom folding device, including a machine body, a bag feeding device, and a bag bottom separating device, characterized in that the bag feeding device and the bag bottom separating device are arranged in parallel, and a cyclically moving bag bottom opening and folding device is provided on the machine body, the bag bottom opening and folding device moves synchronously with the paper bag body on the bag feeding device, and the bag bottom opening and folding device includes a bottom plate and bag holding rods moving toward each other, the bag holding rods can move radially, and a swinging folding plate is provided on the bag bottom opening and folding device.

[0005] The bag-supporting rods include left and right bag-supporting rods, and the swinging folding plates are arranged on the left and right bag-supporting rods.

[0006] The bag-supporting rod is provided with a space for avoiding the folding plate.

[0007] A stopper bar close to the bag feeding device is installed on the machine body.

[0008] The left and right bag-supporting rods each include a bag-supporting rod body, an upper rod and a lower rod, the upper rod and the lower rod are both mounted on the bag-supporting rod body, and there is a gap between the upper rod and the lower rod, an avoidance groove is provided on the folding plate, and the blocking rod passes through the avoidance groove and extends into the gap between the upper rod and the lower rod during the movement of the bag bottom supporting and folding device.

[0009] The bag bottom separating device comprises a lower negative pressure box installed on the machine body and a lower belt with a circulating transmission, wherein the lower belt is provided with adsorption holes, the lower belt is tightly attached to the lower negative pressure box, and a suction nozzle which moves with the paper bag body is provided above the lower negative pressure box.

[0010] The suction nozzle is mounted on the swing rod through a mounting plate.

[0011] Another structure of the bag bottom separating device includes a lower negative pressure box installed on the machine body and a lower belt with a circulating transmission, the lower belt is provided with lower adsorption holes, the lower belt is tightly attached to the lower negative pressure box, an upper negative pressure box is provided above the lower negative pressure box, and a circularly driven upper belt is provided, the upper belt is provided with upper adsorption holes, the upper belt is tightly attached to the upper and lower negative pressure boxes, and the upper negative pressure box and the upper belt are simultaneously raised and lowered.

[0012] The machine body is provided with a cyclically moving transmission chain, and connecting plates are equally fixed on the transmission chain. The bag bottom opening and folding device moves linearly on the connecting plates under the action of the driving device.

[0013] Further, the driving device includes a first guide plate provided with a cam surface, a linear guide is provided on the connecting plate, the bottom plate is matched with the linear guide through a slider, the bottom plate is in dynamic contact with the cam surface, and a return spring is provided between the slider and the connecting plate.

[0014] Further, the cam surface includes a primary cam surface, a secondary cam surface, and a return cam surface.

[0015] The left and right bag-supporting rods are respectively installed on corresponding left and right sliders, the left and right sliders are matched with an axial guide installed on the bottom plate, the left slider is connected to a first rack, the right slider is connected to a second rack, and a gear meshing with the first rack and the second rack is provided between the first rack and the second rack, and the gear is driven by a driving member.

[0016] The driving member includes a first swing arm and a second guide plate, first and second curved surfaces are respectively provided at two end portions of the second guide plate, the first swing arm is in dynamic contact with the first and second curved surfaces of the second guide plate, wherein the first curved surface causes the first swing arm to swing leftward, and the second curved surface causes the first swing arm to swing rightward.

[0017] The folding plate is connected with a first gear, the gear shaft of the first gear is rotatably installed on the left and right bag-supporting rods, and a second gear is installed on the left and right bag-supporting rods, the second gear meshes with the corresponding first gear, and the second gear is driven by a driving assembly.

[0018] The driving assembly includes a second swing arm and a third guide plate, third and fourth curved surfaces are respectively provided at two end portions of the third guide plate, the second swing arm is in dynamic contact with the third and fourth curved surfaces, wherein the third curved surface causes the second swing arm to swing leftward, and the fourth curved surface causes the second swing arm to swing rightward.

[0019] The above-mentioned stop rod is radially movably installed on the machine body.

[0020] The tail end of the bag-feeding device is provided with an upper and lower side folding device, the upper and lower side folding device includes a first lower folding plate, a first upper folding plate, a second lower folding plate, a second upper folding plate, and an upper turning plate, wherein the first lower folding plate and the first upper folding plate are oppositely arranged, the second lower folding plate and the second upper folding plate are oppositely arranged, the upper turning plate is connected to the tail end of the second lower folding plate, an upper glue wheel is provided outside the second lower folding plate, and gaps for the paper bag to pass through are provided between the first lower folding plate, the first upper folding plate, the second lower folding plate, the second upper folding plate, the upper turning plate and the paper bag conveying surface.

[0021] With this structure of the present invention, after the left and right sides of the bottom of the paper bag are folded, the left and right sides of the bottom are perpendicular to the upper and lower sides of the bottom, ensuring that no wrinkles are generated after the bottom of the bag is formed and it is flat. This is particularly suitable for the bottom folding of paper bags with a bag height less than 40 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention has the following drawings:

[0023] Figure 1 is the overall structure diagram of the present invention;

[0024] Figure 2 is the structure diagram of the bag feeding device of the present invention;

[0025] Figure 3 is the structure diagram of the bottom separating device of the present invention;

[0026] Figure 4 is the structure diagram of the second embodiment of the bottom separating device of the present invention;

[0027] Figure 5 is the view of the second embodiment of the bottom separating device of the present invention in another direction;

[0028] Figure 6 is the state diagram of the bottom separating device of the second embodiment of the present invention after separating the bottom;

[0029] Figure 7 is the structure diagram of the bottom spreading and folding device of the present invention;

[0030] Figure 8 of the present invention Figure 7 is the structure diagram of another viewing direction;

[0031] Figure 9 is the structure diagram of the first guide plate of the present invention;

[0032] Figure 10 is the structure diagram of the second guide plate of the present invention;

[0033] Figure 11 is the structure diagram of the third guide plate of the present invention;

[0034] Figure 12 is the combined structure diagram of the bottom spreading and folding device and the bottom separating device of the present invention;

[0035] Figure 13 is the state diagram of the bag supporting rod of the bottom spreading and folding device of the present invention when it is first inserted into the bottom;

[0036] Figure 14 is the state diagram of the bag supporting rod of the bottom spreading and folding device of the present invention when it is second inserted into the bottom;

[0037] Figure 15It is a state diagram after the bag bottom is opened by the bag bottom opening and folding device of the present invention;

[0038] Figure 16 It is a state diagram in which the folding plate on the right side of the present invention folds the right side edge of the bag bottom;

[0039] Figure 17 It is a state diagram in which the folding plate on the left side of the present invention folds the right side edge of the bag bottom;

[0040] Figure 18 It is a state diagram when the retaining rod of the present invention is inserted;

[0041] Figure 19 It is a state diagram after the retaining rod of the present invention is inserted;

[0042] Figure 20 It is a structural diagram of the retaining rod of the present invention;

[0043] Figure 21 It is a structural diagram in which the retaining rod of the present invention can move radially;

[0044] Figure 22 For the present invention Figure 21 A structural diagram from another viewing direction;

[0045] Figure 23 It is a structural diagram of the upper and lower side folding device of the present invention;

[0046] Figure 24 It is a structural diagram of the second embodiment of the first guide plate of the present invention;

[0047] Figure 25 For the present invention Figure 24 The cooperation diagram of the first guide plate shown in the present invention installed on the machine body and the bag bottom opening and folding device. Detailed implementation mode

[0048] Referring to the attached drawings, this paper bag bottom folding device includes a machine body 1, a bag feeding device 2, and a bag bottom separating device 3. The bag feeding device 2 and the bag bottom separating device 3 are arranged in parallel. The bag feeding device 2 includes a driving belt 21 and a pressing wheel 22. After the paper bag enters, it is located between the driving belt 21 and the pressing wheel 22. Under the action of the driving belt 21, the paper bag is conveyed. A circulating and moving bag bottom expanding and folding device 4 is provided on the machine body 1. The bag bottom expanding and folding device 4 moves synchronously with the paper bag body 10 on the bag feeding device 2. The bag bottom expanding and folding device 4 includes a bottom plate 84 and bag expanding rods moving towards each other. The bag expanding rods can move radially. A swinging folding plate 896 is provided on the bag bottom expanding and folding device 4. The bag expanding rods include left and right bag expanding rods. Specifically, the swinging folding plate 896 is installed on the left and right bag expanding rods. A space for avoiding the folding plate 896 is provided on the bag expanding rods. By setting the ends of the left and right bag expanding rods in an L shape, a space for avoiding the folding plate 896 is formed. Of course, there are many ways to represent this space for avoiding the folding plate 896. For example, a bent structure is set on the left and right bag expanding rods to form a recessed groove, which also achieves the purpose.

[0049] The bag bottom separating device 4 includes a lower negative pressure box 33 installed on the machine body 1 and a lower belt 34 with a circulating drive. Adsorption holes are provided on the lower belt 34. The lower belt 34 is closely attached to the lower negative pressure box 33. A suction nozzle 32 that moves with the paper bag body 10 is provided above the lower negative pressure box 33. There are two ways for it to move with the paper bag. The first way is to install the suction nozzle 32 on a swinging rod 31 through a mounting plate. When a paper bag with an M-shaped side is conveyed by the bag feeding device 2 and one side of the bag bottom faces the circulating lower belt 34 and is conveyed onto the lower belt 34, during the movement of the lower belt 34, under the action of the lower negative pressure box 33, through the adsorption holes, the lower edge of the paper bag bottom is adsorbed. At the same time, the suction nozzle 32 above the lower negative pressure box 33 sucks the upper edge of the paper bag bottom. After the suction nozzle 32 swings, the upper and lower edges of the bag bottom are separated, as Figure 3 shown.

[0050] Another way of following the movement of the suction nozzle is: the suction nozzle can also be installed on the suction nozzle slider through the mounting plate, the suction nozzle slider cooperates with the suction nozzle guide rail, and the suction nozzle slider is driven by the first driving component, the suction nozzle guide rail is connected to the lifting slider, the lifting slider cooperates with the lifting guide rail, and the lifting slider is driven by the second driving member. After the paper bag body 10 enters the lower belt 34, the suction nozzle sucks the upper side of the paper bag, and after the first driving member drives the suction nozzle slider to move horizontally on the suction nozzle slide rail for a distance, the second driving member drives the lifting slider on the lifting slide rail, so that the suction nozzle rises and separates the upper side of the bag bottom from the lower side; after the suction nozzle is cut off, the first driving member returns the suction nozzle slider to its position, and after the suction nozzle slider returns to its position, the first driving member returns the lifting slider to its position, and the suction nozzle is in the next suction position. This method is to make the suction nozzle move in a U-shaped motion. Through the above description, the technology in this field can be well known.

[0051] The bag bottom separating device can also be used in the following manner: it includes a lower negative pressure box 33 installed on the body 1 and a lower belt 34 with a circulating transmission, the lower belt 34 is provided with lower adsorption holes, the lower belt 34 is tightly attached to the lower negative pressure box 33, an upper negative pressure box 35 is provided above the lower negative pressure box 33, and a circularly driven upper belt 36 is provided, the upper belt 36 is provided with upper adsorption holes, the upper belt 36 is tightly attached to the upper and lower negative pressure boxes 35, and the upper negative pressure box 35 and the upper belt 36 are arranged to be lifted up and down. Specifically, the upper negative pressure box 35 and the transmission wheel around the upper belt 36 are installed on the movable plate 37, and a top block 38 is set at the top of the movable plate 37. The top block 38 can be a bearing. A transmission cam 39 is set below the top block 38. The transmission cam 39 is in dynamic contact with the top block 38. Of course, the movable plate 37 cooperates with the slide rail through the slider. When the transmission cam 39 rotates, it pushes the top block 38 to lift the movable plate 37, thereby making the upper negative pressure box 35 and the upper belt 36 rise and fall. After the bottom of the paper bag enters between the lower belt 34 and the upper belt 36, the upper and lower belts 36 drive the paper bag to be transported forward while separating the upper and lower sides of the paper bag. Those skilled in the art will know that the pulleys around the lower belt 34 and the upper belt 36 need to be equipped with a driver to drive the belt. Figures 4 - 6 shown.

[0052] There are many ways to separate the upper and lower sides of the bag bottom, which will not be listed one by one.

[0053] The machine body 1 is provided with a circulating transmission chain 8, and connecting plates 81 are equally fixed on the transmission chain 8. The bag bottom opening and folding device 4 moves linearly on the connecting plates 81 under the action of the driving device. After the driving device is working, the bag bottom opening and folding device 4 is driven to be inserted into the space separated by the upper and lower sides of the bag bottom.

[0054] Specifically, the driving device includes a first guide plate 5, on which a cam surface is provided. A linear guide rail 82 is provided on the connecting plate 81, and the bottom plate 84 is matched with the linear guide rail 82 through a slider 83. The bottom plate 84 is in dynamic contact with the cam surface, and a return spring 888 is provided between the slider 83 and the connecting plate 81. The above-mentioned cam surface includes a primary cam surface 51, a secondary cam surface 52, and a return cam surface 53. There are two structures for forming the above-mentioned cam surface. In one structure, a wheel groove 54 is provided on the first guide plate 5, and the above-mentioned primary cam surface 51, secondary cam surface 52, and return cam surface 53 are arranged on the side wall of the wheel groove 54. A first roller 85 is installed on the bottom plate 84, and the first roller 85 is located in the wheel groove 54. After the transmission chain 8 is driven, it drives the connecting plate 81 and the bottom plate 84 to move. After the first roller 85 on the bottom plate 84 slides in the wheel groove 54 and the first roller 85 rolls to the primary convex surface 51, it pushes the bottom plate 84 to move on the linear guide rail 82 through the slider 83. Therefore, it pushes the left and right bag-supporting rods of the bag bottom opening and folding device 4 to be inserted into the space separated by the upper and lower sides of the bag bottom for the first time; when the first roller 85 rolls to the secondary convex surface 52, it again pushes the bottom plate 84 to move on the linear guide rail 82 through the slider 83, so that the left and right bag-supporting rods of the bag bottom opening and folding device 4 are inserted into the space separated by the upper and lower sides of the bag bottom for the second time. After the first roller 85 passes through the return cam surface 53, it returns the bag bottom opening and folding device 4. The function of the return spring 888 is to make the first roller 85 always roll against one side of the wheel groove 54 to ensure its stability. The structure of the first guide plate 5 is as Figure 9 shown. In another structure, the cam surface is directly provided on the side surface of the first guide plate 5. A first roller 85 is installed on the bottom plate 84, and the first roller 85 is in direct dynamic contact with the cam surface. The function of the return spring 888 is to make the first roller 85 always contact the cam surface, and at the same time, the bag bottom opening and folding device is returned at the return cam surface 54. The first guide plate of this structure is as Figure 24 shown, and the matching state of its first roller 85 and the cam surface is as Figure 25 shown. The reason for pushing the bag bottom opening and folding device 4 separately twice in this embodiment is that there is an overlapping part between the inlet end of the first guide plate 5 and the lower belt 34 of the circulating drive on the plane. If the bag bottom opening and folding device 4 is inserted into the space separated by the upper and lower sides of the bag bottom at one time, it will affect the effect of separating the upper and lower sides of the bag bottom. Therefore, if the first guide plate 5 and the lower belt 34 of the circulating drive are designed to have no overlapping section, the bag bottom opening and folding device 4 can also be inserted at one time, and only a primary cam surface is needed.

[0055] Specifically, the left and right bag-supporting rods of the bag bottom opening and folding device 4 move toward each other to open the bag bottom in the following manner: the left and right bag-supporting rods are respectively installed on the corresponding left and right sliders 8911 and 8912, and the left and right sliders 8911 and 8912 cooperate with the axial guide rails 89 installed on the base plate 84, the left slider 8911 is connected to the first rack 86, the right slider 8912 is connected to the second rack 87, and a gear 88 meshing with the first rack 86 and the second rack 87 is provided between the first rack 86 and the second rack 87, the gear 88 is driven by a driving member, and a first return spring 902 is connected between the left and right sliders 8911 and 8912. The driving member includes a first swing arm 881 and a second guide plate 6, wherein the two ends of the second guide plate 6 are respectively provided with a first curved surface 61 and a second curved surface 62, wherein the first swing arm 881 is in dynamic contact with the first curved surface 61 and the second curved surface 62 of the second guide plate 6, wherein the first curved surface 61 enables the first swing arm 881 to swing to the left, separating the left and right bag-supporting rods to open the bag bottom; the second curved surface 62 enables the first swing arm 881 to swing to the right, resetting the left and right bag-supporting rods. The function of the first reset spring 902 is to make the return of the left and right sliders 8911, 8912 more stable and rapid. In this embodiment, the first swing arm 881 is also provided with a second roller 882. When the second roller 882 enters the first curved surface 61, the first swing arm 881 swings and drives the gear 88 to rotate. After the gear 88 rotates, the first rack 86 and the second rack 87 on both sides thereof move toward each other and drive their respective sliders to move on the axial guide rail 89. The left and right bag-supporting rods on the sliders are separated, so that the bottom of the bag can be opened, making the bottom of the bag in the shape of a "mouth".

[0056] When the above-mentioned folding plate 896 swings, it will fold the left and right sides of the bag bottom inward. The folding plates 896 on the left and right bag supporting rods are symmetrically arranged. Taking the folding plate 896 on the right side as an example, the following description is as follows: The folding plate 896 is connected with a first gear 898. The gear shaft of the first gear 898 is rotatably installed on the right bag supporting rod 8923, and a second gear 899 is installed on the right bag supporting rod 8923. The second gear 899 meshes with the first gear 898. The second gear 899 is driven by a driving component. The driving component includes a second swing arm 900 and a third guide plate 7. The two ends of the third guide plate 7 are respectively provided with a third curved surface 71 and a fourth curved surface 72. The second swing arm 900 is in dynamic contact with the third curved surface 71 and the fourth curved surface 72. A second return spring 901 is provided between the folding plate 896 and the right bag supporting rod 8923. Wherein the third curved surface 71 causes the second swing arm 900 to swing to the left, and the fourth curved surface 72 causes the second swing arm 900 to swing to the right. A third roller 905 is provided on the second swing arm 900. When the third roller 905 passes through the third curved surface 71 of the third guide plate 7, the second swing arm 900 swings to the left, driving the second gear 899 to rotate, and driving the first gear 898 to rotate. After the first gear 898 rotates, it causes the folding plate 896 to swing. When swinging inward, it will fold the left and right sides of the bag bottom inward. Since the right bag supporting rod 8923 is in an L shape and has a space to avoid the folding plate 896, when the folding plate 896 swings inward, it will not be interfered by the right bag supporting rod 8932, and the right side of the bag bottom can be easily and conveniently folded inward. When the third roller 905 passes through the fourth curved surface 72, under the action of the second return spring 901, the folding plate 896 returns to its original position; similarly, when the second swing arm on the left enters the third curved surface 71, the swinging direction of the folding plate on the left is opposite to that of the folding plate 896 on the right, folding the left side of the bag bottom inward. In this way, the inward folding process of the left and right sides of the bag bottom is completed.

[0057] A stop bar 9 is installed on the machine body 11 near the bag feeding device. After the bottom bag opening and folding device 4 returns to its position, as the paper bag body is conveyed, the stop bar 9 presses against the left and right sides of the bottom of the bag that has been folded inward to prevent rebound. When the left and right bag supporting rods of the bottom bag opening and folding device 4 are still inside the bottom of the bag (i.e., not in the retracted position), the structures of the left and right bag supporting rods are as follows: both the left and right bag supporting rods include a bag supporting rod body 892, an upper rod 894, and a lower rod 895. The upper rod 894 and the lower rod 895 are both installed on the bag supporting rod body, and there is a gap between the upper rod 894 and the lower rod 895. An avoidance groove 897 is provided on the folding plate 896, and at the same time, a waist-shaped groove 903 is provided on the upper rod 894. It is fixed by passing a bolt 904 through the waist-shaped groove 903. When the height of the paper bag changes, loosen the bolt 904, adjust the distance of the gap between the upper rod 894 and the lower rod 895 to adapt to the height of the paper bag, and then tighten the bolt 904. The stop bar 9 extends into the gap between the upper rod 894 and the lower rod 895 through the avoidance groove 897 during the movement of the bottom bag opening and folding device 4. When the folding plate 896 swings inward to fold the left and right sides of the bottom of the bag inward, as the paper bag and the bottom bag opening and folding device 4 move, the stop bar 9 will slowly insert into the gap between the upper rod 894 and the lower rod 895 to block the left and right sides of the folded bottom of the bag and prevent the left and right sides of the bottom of the bag from rebounding. The stop bar 9 here can be fixedly installed or can be made to move radially. When the stop bar 9 is fixedly installed, one side of the stop bar 9 is set as an inclined surface 91. Therefore, when the stop bar 9 is inserted into the gap between the upper rod 894 and the lower rod 895, under the action of the inclined surface 91, the left and right sides of the bottom of the bag are slowly pressed to prevent it from rebounding, as Figure 20 shown. When the stop bar 9 is designed to have a radially movable structure, the inclined surface 91 structure on the stop bar 9 is cancelled; that is, the stop bar 9 is fixed on a slider 91 that cooperates with a slide rail 92, and the stop bar 9 is in dynamic contact with a cam 93. A third return spring 94 is provided between the slider 91 and the slide rail 92, and a fourth roller 95 is provided on the stop bar 9. The fourth roller 95 contacts the cam surface of the cam 94. After the cam 93 rotates, the stop bar 9 can be moved to press against the left and right sides of the folded bottom of the bag. After the fourth roller 95 leaves the highest point of the cam 93, it returns under the action of the third return spring 94. The cam 93 rotates as follows: A first bevel gear 96 is connected to the shaft of the cam 93, and a second bevel gear 97 is installed on the horizontal shaft of the machine body 1. The first bevel gear 96 meshes with the second bevel gear 97. After the horizontal shaft rotates, it drives the cam 93 to rotate. As Figure 21 , 22 shown.

[0058] A top and bottom side folding device is provided at the tail end of the bag feeding device. The top and bottom side folding device includes a first lower folding plate 101, a first upper folding plate 102, a second lower folding plate 104, a second upper folding plate 105, and an upper turning plate 106. Among them, the first lower folding plate 101 and the first upper folding plate 102 are arranged opposite to each other, the second lower folding plate 104 and the second upper folding plate 105 are arranged opposite to each other, the upper turning plate 106 is connected to the tail end of the second lower folding plate 104, an upper gluing wheel 103 is provided outside the second lower folding plate 104, and there is a gap for the paper bag to pass through between the first lower folding plate 101, the first upper folding plate 102, the second lower folding plate 104, the second upper folding plate 105, the upper turning plate 106 and the paper bag conveying surface. This structure folds the top and bottom sides of the paper bag. Before folding the bottom side of the paper bag, the upper gluing wheel 103 is used to apply glue to the bottom side of the paper bag. After folding, the bottom of the paper bag is pasted up.

[0059] The working process of the present invention will be described below:

[0060] The paper bag body 10 formed into an M shape is horizontally fed between the drive belt 21 and the pressure wheel 22 of the bag feeding device 2 through the input mechanism. The upper and lower side edges of the bottom of the paper bag body 10 face the side of the bottom separating device 3. During the conveyance of the paper bag body 10, through the bottom separating device 3, the upper and lower side edges of the paper bag bottom are separated. At the same time, under the drive of the drive chain 8, the bottom expanding and folding device 4 moves to the position where the upper and lower side edges of the bottom are separated. The drive chain 8 and the drive belt 21 are synchronously driven. Under the action of the first guide plate 5, the bottom plate 84 of the bottom expanding and folding device 4 moves along the linear guide 82, so that the left and right bottom expanding rods of the bottom expanding and folding device 4 are inserted into the square-shaped cavity where the upper and lower side edges of the bottom are separated. As the drive chain 8 and the drive belt 21 continue to be synchronously driven, when the second roller 881 contacts the first curved surface 61 of the second guide plate 6, under the action of the first curved surface 61, the first swing arm 881 swings, causing the gear 88 to rotate, so that the first rack 86 and the second rack 87 move towards each other. Therefore, the sliders 8911 and 8912 connected to the first rack 86 and the second rack 87 move towards each other on the axial guide 89, and the left and right bottom expanding rods connected to their respective sliders separate and lean against the left and right side edges of the bottom respectively, expanding the left and right side edges, making the bottom of the paper bag in a square shape. The drive chain 8 and the drive belt 21 continue to be synchronously driven. When the third roller 905 on the right second swing arm 900 contacts the third curved surface 71 of the third guide plate 7, the right second swing arm 900 swings, driving the second gear 899 and the first gear 898 to rotate, causing the folding plate 896 to swing inwards, so that the right side edge of the bottom is folded inwards. When the third roller on the left second swing arm contacts the third curved surface 71 of the third guide plate 7, the left side edge of the bottom is also folded inwards, completing the process of folding the left and right side edges of the bottom inwards. When the paper bag body 10 moves again, the stop rod 9 passes through the avoidance groove 897 of the folding plate 896 and inserts into the gap between the upper rod 894 and the lower rod 895, and at the same time, the stop rod 9 moves towards the bottom of the bag to block the folded left and right side edges of the bottom to prevent the left and right side edges of the bottom from rebounding. Then, the third roller on the second swing arm 900 successively passes through the fourth curved surface 72 of the third guide plate 7, the second roller 882 on the first swing arm 881 passes through the second curved surface 62 on the second guide plate 6, and the first roller 85 on the bottom plate 84 passes through the return cam surface 53, so that the folding plate 896, the left and right bottom expanding rods, and the entire bottom expanding and folding device 4 all return to their original positions.After that, the paper bag body 10 is sent to the next working station, and the upper and lower side edges are folded by the upper and lower side folding device. Specifically, after the paper bag passes through the gap between the first lower folding plate 101 and the conveyor belt, the first lower folding plate 101 presses the bag body 10 of the paper bag, and the first upper folding plate 102 extends into the gap between the upper and lower side edges at the bottom of the bag. With the transmission of the paper bag body 10, under the action of the first upper folding plate 102, the upper side edge of the bag bottom is folded outwards. At the same time, the glue application wheel 103 sprays glue on the lower side edge of the bag bottom. Then the paper bag body enters the gap between the second lower folding plate 104 and the conveyor belt. The second lower folding plate 104 is offset from the first lower folding plate 101 by a certain distance. Under the action of the second upper folding plate 105, the part of the upper side edge folded outwards is roughly folded in half. After the paper bag body 10 continues to be transmitted, under the action of the upper folding plate 106, the lower side edge of the paper bag bottom is folded upwards and adhered to the part folded in half with the upper side edge, thus pasting the paper bag bottom to complete the process of folding the bottom of the paper bag.

[0061] It should be noted that in the embodiments of the present invention, the movement of the bottom bag opening and folding device, the movement of the left and right bag supporting rods, the swing of the folding plate, the lifting of the upper negative pressure box, and the movement of the blocking rod are all driven by a pure mechanical cam type. As known to those skilled in the art, there are many such driving methods. For example, the bottom plate of the bottom bag opening and folding device is directly driven by a cylinder, or by the method of a motor and a lead screw. The left and right bag supporting rods are directly driven by a double-acting cylinder, or the swing arm of the gear is directly connected to the cylinder, or the slider of the left and right bag supporting rods is screwed to a lead screw with opposite directions, and the lead screw is driven by a motor; the folding plate is directly driven by a cylinder, etc. The moving plate is directly driven by a cylinder or by the cooperation of a motor and a lead screw, and the blocking rod is directly driven by a cylinder. These driving methods are all simple replacements of the prior art.

[0062] In the description of the present invention, it should be understood that the directions indicated by the terms "front", "left", "right", "upper", "lower", "inner", "axial", "radial", etc. are the directions shown in the basic drawings. The so-called "axial direction" refers to the moving direction of the paper bag body, and the so-called "radial direction" is the direction perpendicular to the "axial direction". It is only for the convenience of description and should not be construed as a limitation of the present invention.

Claims

1. A paper bag bottom folding device, comprising a machine body (1), a bag feeding device (2), and a bag bottom separating device (3), characterized in that The bag feeding device (2) is arranged in parallel with the bag bottom separating device (3). A bag bottom expanding and folding device (4) that moves cyclically is provided on the machine body (1). The bag bottom expanding and folding device (4) moves synchronously with the paper bag body (10) on the bag feeding device (2). The bag bottom expanding and folding device (4) includes a bottom plate (84) and bag supporting rods that move towards each other. The bag supporting rods can move radially. A swinging folding plate (896) is provided on the bag bottom expanding and folding device (4). A stop rod (9) close to the bag feeding device (2) is installed on the machine body (1). The bag supporting rods include a bag supporting rod body, an upper rod (894), and a lower rod (895). The upper rod (894) and the lower rod (895) are both installed on the bag supporting rod body (892), and there is a gap between the upper rod (894) and the lower rod (895). An avoidance groove (897) is provided on the folding plate (896). The stop rod (9) passes through the avoidance groove (897) and extends into the gap between the upper rod (894) and the lower rod (895) during the movement of the bag bottom expanding and folding device.

2. The paper bag bottom folding device according to claim 1, characterized in that, The bag supporting rods include left and right bag supporting rods. The swinging folding plate (896) is arranged on the left and right bag supporting rods.

3. The paper bag bottom folding device according to claim 1, characterized in that A space for avoiding the folding plate (896) is provided on the bag supporting rods.

4. The paper bag bottom folding device according to claim 1, characterized in that The bag bottom separating device (3) includes a lower negative pressure box (33) installed on the machine body (1) and a circulating lower belt (34). Adsorption holes are provided on the lower belt (34). The lower belt (34) is closely attached to the lower negative pressure box (33), and a suction nozzle (32) that follows the movement of the paper bag body is provided above the lower negative pressure box (33).

5. The paper bag bottom folding device according to claim 4, characterized in that The suction nozzle (32) is installed on a swinging rod (31) through a mounting plate.

6. The paper bag bottom folding device according to claim 1, characterized in that The bag bottom separating device (3) includes a lower negative pressure box (33) installed on the machine body (1) and a circulating lower belt (34). Lower adsorption holes are provided on the lower belt (34). The lower belt (34) is closely attached to the lower negative pressure box (33). An upper negative pressure box (35) is provided above the lower negative pressure box (33), and a circulating upper belt (36) is provided. Upper adsorption holes are provided on the upper belt (36). The upper belt (36) is closely attached to the upper negative pressure box (35), and the upper negative pressure box (35) and the upper belt (36) are arranged to move up and down simultaneously.

7. The paper bag bottom folding device according to claim 1, characterized in that A circulating transmission chain (8) is provided on the machine body (1). Connecting plates (81) are equally fixed on the transmission chain (8). The bag bottom expanding and folding device (4) linearly moves on the connecting plates (81) under the action of a driving device.

8. The paper bag bottom folding device according to claim 7, characterized in that The driving device includes a first guide plate (5). A cam surface is provided on the first guide plate (5). A linear guide rail (82) is provided on the connecting plate (81). The bottom plate (84) is matched with the linear guide rail (82) through a slider (83). The bottom plate (84) is in dynamic contact with the cam surface, and a return spring (888) is provided between the slider (83) and the connecting plate (81).

9. The paper bag bottom folding device according to claim 8, characterized in that The cam surface includes a primary cam surface (51), a secondary cam surface (52), and a return cam surface (53).

10. The paper bag bottom folding device according to claim 2, characterized in that The left and right bag-supporting rods are respectively installed on corresponding left and right sliders (8911, 8912). The left and right sliders (8911, 8912) cooperate with an axial guide rail (89) installed on the base plate (84). The left slider (8911) is connected to a first rack (86), the right slider (8912) is connected to a second rack (87), and a gear (88) meshing with the first rack (86) and the second rack (87) is provided between the first rack (86) and the second rack (87). The gear is driven by a driving member.

11. The paper bag bottom folding device according to claim 10, characterized in that The driving member includes a first swing arm (881) and a second guide plate (6). First curved surfaces (61) and second curved surfaces (62) are respectively provided at two end portions of the second guide plate (6). The first swing arm (881) is in dynamic contact with the first curved surface (61) and the second curved surface (62) of the second guide plate (6). Among them, the first curved surface (61) causes the first swing arm (881) to swing to the left, and the second curved surface (62) causes the first swing arm (881) to swing to the right.

12. The paper bag bottom folding device according to claim 2, wherein The folding plate (896) is connected with a first gear (898). The gear shaft of the first gear (898) is rotatably installed on the left and right bag-supporting rods, and a second gear (899) is installed on the left and right bag-supporting rods. The second gear (899) meshes with the corresponding first gear (898), and the second gear (899) is driven by a driving assembly.

13. The paper bag bottom folding device according to claim 12, characterized in that The driving assembly includes a second swing arm (900) and a third guide plate (7). Third curved surfaces (71) and fourth curved surfaces (72) are respectively provided at two end portions of the third guide plate (7). The second swing arm (900) is in dynamic contact with the third curved surface (71) and the fourth curved surface (72). Among them, the third curved surface (71) causes the second swing arm (900) to swing to the left, and the fourth curved surface (72) causes the second swing arm (900) to swing to the right.

14. The paper bag bottom folding device according to claim 1, characterized in that The stop rod (9) is radially movably installed on the machine body (1).

15. The paper bag bottom folding device according to claim 1, characterized in that The tail end of the bag feeding device is provided with an upper and lower side folding device. The upper and lower side folding device includes a first lower folding plate (101), a first upper folding plate (102), a second lower folding plate (104), a second upper folding plate (105), and an upper turning plate (106). Among them, the first lower folding plate (101) and the first upper folding plate (102) are oppositely arranged, the second lower folding plate (104) and the second upper folding plate (105) are oppositely arranged, the upper turning plate (106) is connected to the tail end of the second lower folding plate (104), an upper glue wheel (103) is provided outside the second lower folding plate (104), and gaps for the paper bag to pass through are provided between the first lower folding plate (101), the first upper folding plate (102), the second lower folding plate (104), the second upper folding plate (105), and the upper turning plate (106) and the paper bag conveying surface.

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