CN116968385B - Paper bag unreeling device and technology - Google Patents

Abstract

The invention relates to the technical field of paper bag processing equipment, and particularly discloses a paper bag unreeling device and a technology, wherein the paper bag unreeling device comprises: support base and backup pad, be connected with unreeling wheel through unreeling axle in the backup pad, be provided with auxiliary device in the backup pad, auxiliary device includes U template, first gear, first drive arrangement, elastic component and stop device, is equipped with pressure sensor between unreeling axle and the backup pad. The paper bag unreeling process comprises the following steps: the paper roll is installed and tensioned, so that the first driving device drives the first rack or the second rack of the U-shaped plate to be meshed with the first gear according to the pressure value monitored by the pressure sensor, and the elastic piece can release energy or store energy; when the paper roll is replaced, the limiting device limits the elastic piece to move; according to the paper bag unreeling device and process, the elastic piece can release energy or store energy, so that the unreeling is assisted or the unreeling resistance is increased, the paper roll is prevented from being excessively pulled or loosened, and the paper bag unreeling device and process are convenient to process.

Description

Paper bag unreeling device and technology

Technical Field

The invention relates to the technical field of paper bag processing equipment, in particular to a paper bag unreeling device and a paper bag unreeling process.

Background

In order to realize the heat preservation function of the paper bag, a heat preservation layer, such as an aluminum film, is generally covered inside the paper bag. In the production process of paper bags, it is necessary to unwind rolls of paper bags to perform steps such as film coating and pattern printing. In the unreeling process of the paper roll, along with the fact that the paper roll is fewer and fewer, the weight on the unreeling wheel is reduced, therefore, when the force of the tensioning device is kept unchanged, the paper roll can be loosened along with the reduction of the weight, the pulled paper tape can be loosened, and normal operation of subsequent procedures is difficult to guarantee.

The patent of application number 201911214694.8 discloses a meshbelt processing fixed width unwinding device, including frame, unwinding device, meshbelt, unwinding device includes unwinding wheel, axle support, friction device and elevating gear, and the meshbelt is installed on the unwinding wheel, and the unwinding wheel passes through the pivot and installs on the axle support, and elevating gear makes friction device increase gradually with the frictional force between the pivot according to the thickness variation when meshbelt unreels, makes the pulling force of unwinding wheel to meshbelt remain unchanged to this guarantees that meshbelt is in tensioning state all the time.

According to the technical scheme, damping is added to the rotating shaft through friction, abrasion can be caused to the rotating shaft after long-term use, the damping effect on the rotating shaft is affected, the stability of the rotating shaft is affected, and the service life of the rotating shaft is shortened; in addition, this technical scheme can only play the damping effect to the pivot, and when new meshbelt diameter is great weight is great, there is probably to unreel difficulty, and meshbelt is excessively pulled scheduling problem.

Thus, a new paper bag unwind apparatus and process is now needed to address the above-described problems.

Disclosure of Invention

The invention provides a paper bag unreeling device and a paper bag unreeling process, and aims to solve the problems that the unreeling device in the related art is large in abrasion to an unreeling rotating shaft and can not be used for carrying out auxiliary unreeling on the unreeling rotating shaft.

The paper bag unreeling device comprises a supporting base and two supporting plates symmetrically arranged on the supporting base, wherein one sides of the two supporting plates facing each other are respectively and rotatably connected with unreeling wheels, the unreeling wheels are rotatably connected with the corresponding supporting plates through unreeling shafts,

at least one supporting plate is provided with an auxiliary device, the auxiliary device comprises a U-shaped plate, a first gear, a first driving device, an elastic piece and a limiting device, the U-shaped plate is arranged on one side of the supporting plate, on which the unreeling wheel is arranged, the first gear is positioned between two side plates of the U-shaped plate, and a first rack and a second rack are respectively arranged on one side, facing each other, of the two side plates of the U-shaped plate;

the first gear is rotationally connected with the supporting plate through a rotating shaft, one end of the rotating shaft penetrates through the supporting plate and is connected with a second gear, the second gear is meshed with a third gear, the third gear is connected with a corresponding unreeling shaft, and a pressure sensor is arranged between the bottom of the unreeling shaft and the supporting plate;

the elastic piece is located the bottom of U template, the U template along vertical with a drive arrangement sliding connection, a drive arrangement is according to the pressure value that pressure sensor monitored drive U template first rack or second rack with first gear meshes, so that the elastic piece is released energy or energy storage, when changing the scroll, stop device restriction the elastic piece activity.

Preferably, a first T-shaped chute extending vertically is formed in a support plate provided with the auxiliary device, first T-shaped sliders are arranged on two side plates of the U-shaped plate, the U-shaped plate is in sliding connection with the support plate through matching of the first T-shaped sliders and the first T-shaped chute, and the first T-shaped chute allows the U-shaped plate to move to the first rack or the second rack to be meshed with the first gear.

Preferably, the elastic piece comprises a first spring and a movable plate, the bottom end of the first spring is connected with the supporting plate, the top end of the first spring is connected with the movable plate, the limiting device comprises a limiting plate, the limiting plate is connected with a second driving device, and when a paper roll is replaced, the second driving device drives the limiting plate to limit the vertical movement of the movable plate.

Preferably, the limiting plate is arranged on one side, away from the supporting plate where the limiting plate is located, of the movable plate, an inclined plane I which is inclined from top to bottom and from the limiting plate to the position close to the limiting plate is arranged on one side, facing the movable plate, of the movable plate, an inclined plane II which is adaptive to the inclined plane I is arranged on one side, facing the movable plate, of the movable plate, and a friction structure is arranged on the inclined plane I and the inclined plane II.

Preferably, the supporting plate provided with the auxiliary device is in sliding connection with the supporting base, one side of the limiting plate, which deviates from the movable plate, is provided with a second spring, one end of the limiting plate, which is far away from the second spring, is propped against the supporting plate where the limiting plate is located, the second driving device comprises a second driving motor and a screw rod, the second driving motor is fixedly connected with the supporting base, the screw rod is connected with the output end of the second driving motor, the limiting plate is in threaded connection with the screw rod, and the supporting plate where the limiting plate is located is provided with a limiting groove which allows the limiting plate to move along the screw rod.

Preferably, the two support plates are respectively provided with the auxiliary device, the screw is a bidirectional threaded rod, the two limit plates on the support plates are respectively connected with the screw in a threaded manner, and the screw drives the two limit plates to move towards a direction approaching to or away from each other.

Preferably, the first driving device comprises a first driving motor, a driving rod and a driving plate, wherein the first driving motor is fixedly connected with the supporting plate, one end of the driving rod is connected with the output end of the first driving motor, the other end of the driving rod is connected with the driving plate, a second T-shaped sliding groove extending vertically is formed in the driving plate, a second T-shaped sliding block is arranged on the U-shaped plate, and the driving plate is in sliding connection with the U-shaped plate through the cooperation of the second T-shaped sliding groove and the second T-shaped sliding block.

Preferably, the second gear is detachably connected with the rotating shaft, and the third gear is detachably connected with the unreeling shaft.

The paper bag unreeling process provided by the invention adopts the paper bag unreeling device in any one of the technical schemes, and comprises the following steps of:

installing a new paper roll on the two unreeling wheels, and connecting the end part of the paper roll with the tensioning device;

controlling the first driving device to drive the U-shaped plate to move until the first rack is meshed with the first gear, and canceling the limit of the limiting device on the elastic piece;

the elastic piece releases energy to push the U-shaped plate upwards, the U-shaped plate drives the first gear to rotate through the first rack, and the first gear assists the third gear to rotate through the second gear to assist unreeling;

when the pressure sensor detects that the pressure value is equal to 1/2 of the pressure value when a new paper roll is installed, the first driving device is controlled to drive the U-shaped plate to move until the second rack is meshed with the first gear, the unreeling shaft drives the first gear to rotate through the third gear and the second gear, and the first gear drives the U-shaped plate to downwards squeeze the elastic piece through the second rack, so that the unreeling shaft rotation resistance is increased;

when the unreeling of the paper roll is completed, the limiting device is controlled to limit the movement of the elastic piece, and the empty paper roll of the paper roll is taken down.

The beneficial effects of the invention are as follows:

by arranging the auxiliary device, when the new paper roll is unreeled, the elastic piece is enabled to release energy to assist the unreeling shaft to rotate, so that the phenomenon that the paper is transitionally pulled or broken due to the fact that the tension of the tensioning device on the paper is large when the weight of the new paper roll is large is avoided; when the paper roll is unreeled to the half of weight reduction, the elastic piece is stored by the rotation of the unreeled shaft, so that the rotation resistance of the unreeled shaft is increased, the paper roll is prevented from loosening, and the pulled paper tape is prevented from loosening, so that the processing is facilitated.

When the second rack is meshed with the first gear and is switched into the first rack meshed with the first gear, the elastic piece is switched from energy storage to energy release, and the elastic piece is prevented from pushing the U-shaped plate upwards in the switching process by arranging the limiting device, so that energy is dissipated.

By arranging the second gear and the third gear to be detachable, the second gear and the third gear can be replaced according to paper rolls with different specifications and sizes so as to be adjusted to a proper transmission ratio.

Drawings

Fig. 1 is a schematic view of the overall structure of the paper bag unreeling device of the present invention.

Fig. 2 is a top view of the paper bag unwind apparatus of the present invention.

Fig. 3 is a schematic view of the assembly of the left side support plate and the auxiliary device of the paper bag unreeling device of the present invention.

Fig. 4 is a schematic structural view of an auxiliary device of the paper bag unreeling device of the present invention.

Fig. 5 is a sectional view showing a part of the structure of the auxiliary device of the paper bag unreeling device of the present invention.

Fig. 6 is a partial cross-sectional view of the left side support plate of the paper bag unwind apparatus of the present invention.

Fig. 7 is an enlarged view of a portion a in fig. 6.

Reference numerals:

1. a support base; 2. a support plate; 21. t-shaped chute I; 22. a limit groove; 23. a receiving chamber; 3. unreeling wheel; 31. a reel is unreeled; 32. a third gear; 4. a U-shaped plate; 41. a T-shaped sliding block I; 42. a first rack; 43. a second rack; 44. t-shaped sliding blocks II; 5. a first gear; 51. a rotating shaft; 6. a second gear; 7. a first driving motor; 71. a driving rod; 72. a driving plate; 721. t-shaped sliding grooves II; 8. a first spring; 81. a movable plate; 9. a limiting plate; 91. a convex strip; 92. a second spring; 10. a second driving motor; 101. and (5) a screw rod.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

As shown in fig. 1 to 7, and referring to the orientation shown in fig. 1, the paper bag unreeling device of the present invention comprises a support base 1, left and right support plates 2 symmetrically disposed on the support base 1, unreeling wheels 3 rotatably connected to one side of the two support plates 2 toward each other, respectively, the unreeling wheels 3 rotatably connected to the corresponding support plates 2 through unreeling shafts 31, and paper rolls for producing paper bags are mounted on the two unreeling wheels 3.

The two support plates 2 are provided with auxiliary devices, respectively, and the support plates 2 and the auxiliary devices located at the left side of the support base 1 are exemplified. The auxiliary device comprises a U-shaped plate 4, a first gear 5, a first driving device, an elastic piece and a limiting device.

Wherein, U template 4 sets up in the right side of backup pad 2, and the opening of U template 4 is towards backup pad 2. Two T-shaped sliding grooves 21 extending vertically are formed in the right side face of the supporting plate 2, T-shaped sliding blocks 41 are arranged on two side plates of the U-shaped plate 4, the U-shaped plate 4 is in sliding connection with the supporting plate 2 through cooperation of the T-shaped sliding blocks 41 and the T-shaped sliding grooves 21, and the T-shaped sliding blocks 41 of the U-shaped plate 4 can move in the front-back direction in the T-shaped sliding grooves 21. The side of the two side plates of the U-shaped plate 4 facing each other is provided with a first rack 42 and a second rack 43, respectively, and the first gear 5 is located between the two side plates of the U-shaped plate 4.

As shown in fig. 3 to 5, the first gear 5 is rotatably connected to the support plate 2 through a rotation shaft 51, and one end of the rotation shaft 51 penetrates the support plate 2 and is connected to the second gear 6. The unreeling shaft 31 penetrates the supporting plate 2 and is connected with a third gear 32, and the third gear 32 is meshed with the second gear 6. The second gear 6 is detachably connected to the rotation shaft 51, and the third gear 32 is detachably connected to the unreeling shaft 31. A pressure sensor (not shown in the figures) is provided between the bottom of the unwind shaft 31 and the support plate 2.

The first driving device comprises a first driving motor 7, a driving rod 71 and a driving plate 72, wherein the first driving motor 7 is fixedly connected with the supporting plate 2, one end of the driving rod 71 is connected with the output end of the first driving motor 7, and the other end of the driving rod is connected with the driving plate 72. The driving plate 72 is provided with a T-shaped sliding groove II 721 which extends vertically, the right side surface of the U-shaped plate 4 is provided with a T-shaped sliding block II 44, and the driving plate 72 is in sliding connection with the U-shaped plate 4 through the matching of the T-shaped sliding groove II 721 and the T-shaped sliding block II 44.

The elastic component is located the bottom of U template 4, and the elastic component includes first spring 8 and fly leaf 81, and the bottom of first spring 8 is connected with backup pad 2, and the top is connected with fly leaf 81. The movable plate 81 is abutted against the bottom of the U-shaped plate 4.

As shown in fig. 6 and 7, the limiting device comprises a limiting plate 9, the limiting plate 9 is located on the right side of a movable plate 81, a first inclined surface which is inclined from top to bottom and from left to right is arranged on the right side surface of the movable plate 81, and a second inclined surface which is matched with the first inclined surface is arranged on the left side surface of the limiting plate 9. The first and second slopes are provided with friction structures, which are, as an example, ribs 91 continuously arranged along the first and second slopes, respectively, the ribs 91 extending in the front-rear direction.

As shown in fig. 3, 6 and 7, the support plate 2 is slidably connected with the support base 1 along the left-right direction, a limit groove 22 is formed in the support plate 2, and the limit plate 9 is disposed in the limit groove 22 and is movable in the left-right direction in the limit groove 22. The right side of limiting plate 9 is provided with second spring 92, is provided with the chamber 23 that holds second spring 92 on the backup pad 2, and the both ends of second spring 92 are respectively with limiting plate 9 and hold the chamber wall in chamber 23 and offset, and second spring 92 is in compression state all the time.

The limiting plate 9 is connected with a second driving device, and the second driving device comprises a second driving motor 10 and a screw rod 101. The second driving motor 10 is fixedly connected with the supporting base 1, and the lead screw 101 is connected with the output end of the second driving motor 10. The screw rod 101 is a bidirectional threaded rod, the limiting plates 9 on the two support plates 2 are respectively in threaded connection with the screw rod 101, and the screw rod 101 drives the two limiting plates 9 to move towards or away from each other.

The specific working process of the paper bag unreeling device is as follows: in the initial state, the left support plate 2 and the right support plate 2 are respectively positioned at the left end and the right end of the support base 1, the first spring 8 is in a compressed state, and the limiting plate 9 is in extrusion contact with the movable plate 81 to limit the movement of the movable plate 81 and the first spring 8;

placing paper rolls between unreeling wheels 3 of two support plates 2, enabling a first driving motor 7 to drive a U-shaped plate 4 to move backwards until a first rack 42 is meshed with a first gear 5, enabling a second driving motor 10 to drive a screw rod 101 to rotate, enabling the screw rod 101 to drive limiting plates 9 on the two support plates 2 to move towards each other, enabling the limiting plates 9 to push the support plates 2 to move along with the limiting plates due to the fact that second springs 92 are always in a compressed state, keeping extrusion limiting states between the limiting plates 9 and the movable plates 81, and enabling the supporting plates 2 not to move along with the limiting plates 9 when the unreeling wheels 3 on the two support plates 2 clamp the paper rolls, enabling the limiting plates 9 to extrude the second springs 92 to shrink, enabling the limiting plates 9 to start to move towards a direction away from the movable plates 81 until limitation on the movable plates 81 is eliminated;

the tensioning device pulls the paper roll to start unreeling, the first spring 8 pushes the U-shaped plate 4,U plate 4 upwards through the movable plate 81 and drives the first gear 5 to rotate through the first rack 42, the first gear 5 drives the third gear 32 to rotate through the second gear 6, the power for the unreeling shaft 31 to rotate is increased, the unreeling is assisted, and the paper roll is prevented from being excessively pulled;

in the unreeling process, when the pressure sensor detects that the current pressure value is equal to 1/2 of the pressure value when the new paper roll is mounted, the first driving motor 7 drives the U-shaped plate 4 to move forwards until the second rack 43 is meshed with the first gear 5, at the moment, the unreeling shaft 31 drives the third gear 32 to rotate, the third gear 32 drives the first gear 5 to rotate through the second gear 6, the first gear 5 presses the U-shaped plate 4,U downwards through the second rack 43, and the first spring 8 is pressed through the movable plate 81 to contract and store energy;

when unreeling is completed, the second driving motor 10 is used for driving the screw rod 101 to rotate, the screw rod 101 is used for driving the limiting plates 9 on the two supporting plates 2 to move in the direction away from each other, when the inclined planes of the limiting plates 9 are tightly extruded with the inclined planes of the movable plates 81, the limiting plates 9 limit the movement of the movable plates 81 and the first springs 8, along with the continuous movement of the limiting plates 9, the limiting plates 9 extrude the supporting plates 2 to follow the movement of the limiting plates 9 through the movable plates 81, the left supporting plates 2 and the right supporting plates 2 are respectively positioned at the left end and the right end of the supporting base 1, the empty paper cylinders of paper rolls are taken down, and the unreeling operation is completed.

In the above described embodiments, the auxiliary means are provided on each of the two support plates 2, and in other embodiments, the auxiliary means are provided on only one of the support plates.

In the above embodiment, the supporting plate 2 is slidably connected with the supporting base 1, and the limiting plate 9 is driven by the screw rod 101 to drive the supporting plate 2 to move so as to realize the installation and the disassembly of the paper roll, in other embodiments, the supporting plate is fixedly connected with the supporting base, the second spring is omitted between the limiting plate and the supporting plate, the supporting plate is provided with a U-shaped groove, the U-shaped groove is a through groove extending along the left-right direction, the opening of the U-shaped groove faces upwards, after the unreeling wheel is installed on the paper roll, the unreeling shaft on the unreeling wheel is placed in the U-shaped groove from top to bottom through the U-shaped groove and is supported on the supporting plate, and then the unreeling shaft is provided with a third gear, and vice versa during the disassembly.

The paper bag unreeling process of the invention uses the paper bag unreeling device in the embodiment, and the paper bag unreeling process comprises the following steps:

installing a new paper roll on the two unreeling wheels 3, and connecting the end part of the paper roll with a tensioning device;

controlling the first driving device to drive the U-shaped plate 4 to move until the first rack 42 is meshed with the first gear 5, and canceling the limit of the limiting device on the elastic piece;

the unreeling is started, the elastic piece releases energy, the U-shaped plate 4,U plate 4 is pushed upwards to drive the first gear 5 to rotate through the first rack 42, and the first gear 5 assists the third gear 32 to rotate through the second gear 6 to assist unreeling;

when the pressure sensor detects that the current pressure value is equal to 1/2 of the pressure value when the new paper roll is installed, the first driving device is controlled to drive the U-shaped plate 4 to move until the second rack 43 is meshed with the first gear 5, the unreeling shaft 31 drives the first gear 5 to rotate through the third gear 32 and the second gear 6, and the first gear 5 drives the U-shaped plate 4 to downwards squeeze the elastic piece through the second rack 43, so that the rotating resistance of the unreeling shaft 31 is increased;

when the unreeling of the paper roll is completed, the limiting device is controlled to limit the movement of the elastic piece, and the empty paper tube of the paper roll is taken down.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (3)

1. The paper bag unreeling device comprises a supporting base (1), two supporting plates (2) symmetrically arranged on the supporting base (1), unreeling wheels (3) are respectively and rotatably connected to one sides of the two supporting plates (2) facing each other, the unreeling wheels (3) are rotatably connected with the corresponding supporting plates (2) through unreeling shafts (31), and the paper bag unreeling device is characterized in that,

at least one supporting plate (2) is provided with an auxiliary device, the auxiliary device comprises a U-shaped plate (4), a first gear (5), a first driving device, an elastic piece and a limiting device, the U-shaped plate (4) is arranged on one side of the supporting plate (2) where the unreeling wheel (3) is arranged, the first gear (5) is positioned between two side plates of the U-shaped plate (4), and a first rack (42) and a second rack (43) are respectively arranged on one side, facing each other, of the two side plates of the U-shaped plate (4);

the first gear (5) is rotationally connected with the supporting plate (2) through a rotating shaft (51), one end of the rotating shaft (51) penetrates through the supporting plate (2) and is connected with a second gear (6), the second gear (6) is meshed with a third gear (32), the third gear (32) is connected with a corresponding unreeling shaft (31), and a pressure sensor is arranged between the bottom of the unreeling shaft (31) and the supporting plate (2);

the elastic piece is positioned at the bottom of the U-shaped plate (4), the U-shaped plate (4) is vertically connected with the first driving device in a sliding mode, the first driving device drives a first rack (42) or a second rack (43) of the U-shaped plate (4) to be meshed with the first gear (5) according to the pressure value monitored by the pressure sensor, so that the elastic piece can release energy or store energy, and the limiting device limits the elastic piece to move when a paper roll is replaced;

a first T-shaped chute (21) extending vertically is formed in a supporting plate (2) provided with the auxiliary device, first T-shaped sliding blocks (41) are arranged on two side plates of the U-shaped plate (4), the U-shaped plate (4) is in sliding connection with the supporting plate (2) through matching of the first T-shaped sliding blocks (41) and the first T-shaped chute (21), and the first T-shaped chute (21) allows the U-shaped plate (4) to move to the first rack (42) or the second rack (43) to be meshed with the first gear (5);

the elastic piece comprises a first spring (8) and a movable plate (81), the bottom end of the first spring (8) is connected with the supporting plate (2), the top end of the first spring is connected with the movable plate (81), the limiting device comprises a limiting plate (9), the limiting plate (9) is connected with a second driving device, and when a paper roll is replaced, the second driving device drives the limiting plate (9) to limit the vertical movement of the movable plate (81);

the movable plate (81) is provided with a limiting plate (9) at one side deviating from the supporting plate (2) where the movable plate (81) is positioned, one side, facing the limiting plate (9), of the movable plate (81) is provided with a first inclined surface which is inclined from top to bottom and from the limiting plate (9) to the position close to the limiting plate (9), one side, facing the movable plate (81), of the limiting plate (9) is provided with a second inclined surface which is matched with the first inclined surface, and the first inclined surface and the second inclined surface are provided with friction structures;

the support plate (2) provided with the auxiliary device is in sliding connection with the support base (1), one side of the limiting plate (9) deviating from the movable plate (81) is provided with a second spring (92), one end of the second spring (92), which is far away from the limiting plate (9), is propped against the support plate (2) where the limiting plate (9) is located, the second driving device comprises a second driving motor (10) and a screw rod (101), the second driving motor (10) is fixedly connected with the support base (1), the screw rod (101) is connected with the output end of the second driving motor (10), the limiting plate (9) is in threaded connection with the screw rod (101), and the support plate (2) where the limiting plate (9) is located is provided with a limiting groove (22) which allows the limiting plate (9) to move along the screw rod (101);

the two support plates (2) are respectively provided with the auxiliary device, the screw rods (101) are bidirectional threaded rods, the limiting plates (9) on the two support plates (2) are respectively connected with the screw rods (101) in a threaded mode, and the screw rods (101) drive the two limiting plates (9) to move towards a direction approaching to or away from each other;

the first driving device comprises a first driving motor (7), a driving rod (71) and a driving plate (72), wherein the first driving motor (7) is fixedly connected with a supporting plate (2), one end of the driving rod (71) is connected with the output end of the first driving motor (7), the other end of the driving rod is connected with the driving plate (72), a T-shaped sliding groove II (721) extending vertically is formed in the driving plate (72), a T-shaped sliding block II (44) is arranged on the U-shaped plate (4), and the driving plate (72) is in sliding connection with the U-shaped plate (4) through the matching of the T-shaped sliding groove II (721) and the T-shaped sliding block II (44).

2. A paper bag unreeling device according to claim 1, characterized in that the second gear (6) is detachably connected with the rotating shaft (51), and the third gear (32) is detachably connected with the unreeling shaft (31).

3. A paper bag unreeling process, wherein the paper bag unreeling device of any one of claims 1 to 2 is used in the paper bag unreeling process, and the paper bag unreeling process comprises the following steps:

installing a new paper roll on the two unreeling wheels (3), and connecting the end part of the paper roll with a tensioning device;

controlling the first driving device to drive the U-shaped plate (4) to move until the first rack (42) is meshed with the first gear (5), and canceling the limit of the limiting device on the elastic piece;

the unreeling is started, the elastic piece releases energy, the U-shaped plate (4) is pushed upwards, the U-shaped plate (4) drives the first gear (5) to rotate through the first rack (42), and the first gear (5) assists the third gear (32) to rotate through the second gear (6) to assist unreeling;

when the pressure sensor detects that the pressure value is equal to 1/2 of the pressure value when a new paper roll is installed, the first driving device is controlled to drive the U-shaped plate (4) to move until the second rack (43) is meshed with the first gear (5), the unreeling shaft (31) drives the first gear (5) to rotate through the third gear (32) and the second gear (6), and the first gear (5) drives the U-shaped plate (4) to downwards squeeze the elastic piece through the second rack (43), so that the rotating resistance of the unreeling shaft (31) is increased;

when the unreeling of the paper roll is completed, the limiting device is controlled to limit the movement of the elastic piece, and the empty paper roll of the paper roll is taken down.