Inner frame paper folding device

Abstract

The application provides an inner frame paper folding device and belongs to the technical field of inner frame paper production. The inner frame paper folding device comprises a first lifting piece, two conveying pieces, a plurality of first limiting pieces and two second lifting pieces. In the application, two first base areas of the inner frame paper are respectively arranged on the two conveying pieces. Since the distance between the two conveying pieces gradually decreases from a paper conveying end to a paper forming end, the two first base areas move towards the close direction when the two conveying pieces convey the two first base areas from the paper conveying end to the paper forming end. The first lifting piece lifts the first folding area upwards to form an intermediate separation layer. The second lifting piece lifts the second folding area upwards to form a side protruding layer, thereby completing the folding of the inner frame paper. The structure is simple and the operation is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inner frame paper production, and particularly relates to an inner frame paper folding device. BACKGROUND

[0002] The inner frame paper is an important component of a cigarette packet. After being cut to a fixed length and a fixed shape, the inner frame paper is pressed to form five folding lines and is folded at the five folding lines. In the existing YB43A packaging machine, the flat inner lining paper is folded into an M shape by hand, which is low in efficiency and cannot guarantee the quality. SUMMARY

[0003] The present application aims at the deficiency of the prior art and provides an inner frame paper folding device.

[0004] The present application provides an inner frame paper folding device for folding the inner frame paper. The device comprises a first lifting piece, two conveying pieces symmetrically arranged on the two sides of the first lifting piece, a plurality of first limiting pieces arranged above the conveying pieces along the conveying direction of each conveying piece, and two second lifting pieces symmetrically arranged on the two sides of the two conveying pieces. The distance between the two conveying pieces gradually decreases from the paper conveying end to the paper forming end. The inner frame paper comprises a first folding area in the middle, two first base areas symmetrically arranged on the two sides of the first folding area, and second folding areas symmetrically arranged on the two sides of the two first base areas. The first limiting pieces are used to limit the upper part of the first base areas. The two conveying pieces are used to convey the two first base areas from the paper conveying end to the paper forming end, so that the two first base areas move towards each other. The first lifting piece is used to lift the first folding area upwards to form a middle spacer layer. The second lifting piece is used to lift the second folding area upwards to form a side protruding layer.

[0005] Further, the device further comprises a support piece, the conveying pieces are rotationally connected to the support piece, the first lifting piece, the second lifting piece and the first limiting pieces are respectively connected to the support piece, the support piece comprises two first mounting plates arranged in parallel, the conveying piece comprises a first conveying roller, a second conveying roller, a synchronous belt sleeved on the outer periphery of the first conveying roller and the outer periphery of the second conveying roller at both ends, a first driving structure for driving a first rotating shaft, the first rotating shaft sleeved on the inner side of the first conveying roller, and a second rotating shaft sleeved on the inner side of the second conveying roller, and the first rotating shaft and the second rotating shaft are respectively rotationally connected to the first mounting plates.

[0006] Further, the distance between the two first limiting pieces arranged correspondingly gradually decreases along the direction from the paper input end to the paper forming end.

[0007] Further, the first limiting piece comprises a first adjusting structure, a first pressing roller parallel to the plane where the synchronous belt is located, and a third rotating shaft connected to the first pressing roller.

[0008] Further, the first lifting piece comprises a first top plate and a first support plate connected to the first top plate and the first mounting plate respectively.

[0009] Further, the second lifting piece comprises a second top plate parallel to the plane where the top of the synchronous belt is located, a first guide plate connected to the second top plate, and a first support structure connected to the first mounting plate and the second top plate respectively, wherein the first guide plate is arranged in an upward inclination.

[0010] Further, the first mounting plate comprises a first connecting groove arranged at the top and a first plug-in groove arranged at the side and in communication with the bottom end of the first connecting groove, the first adjusting structure comprises a first connecting rod inserted into the first plug-in groove, one end of the third rotating shaft is inserted into the first plug-in groove and connected to the bottom end of the first connecting rod, and the top end of the first connecting rod is connected to the first mounting plate when the third rotating shaft moves to a preset height in the first plug-in groove.

[0011] Further, the first mounting plate further comprises a second plug-in groove arranged at the bottom and in communication with the bottom end of the first connecting groove, the side wall of the first connecting groove is provided with a first internal thread, and the first adjusting structure further comprises a first spring, a second spring, a first screw rod, a first plug-in rod sleeved on the inside of the first spring, and a second plug-in rod connected to the bottom end of the first screw rod, wherein the top end of the first spring is inserted into the first connecting groove and abuts against the first connecting rod, the first screw rod is screwed into the first internal thread, the bottom end of the first screw rod abuts against the second spring, the bottom end of the second plug-in rod is sleeved on the second spring, and the second spring is arranged in the first connecting groove and abuts against the top end of the first connecting rod.

[0012] Further, the first guide plate is rotationally connected to the second top plate, so that the angle between the first guide plate and the second top plate is adjustable; the first guide plate is fixedly connected to the second top plate when the angle between the first guide plate and the second top plate is adjusted to a preset angle; and the first support structure comprises a second support plate fixedly connected to the first mounting plate and an extendable lifting part, wherein the two ends of the lifting part are connected to the second support plate and the second top plate respectively.

[0013] Further, the lifting part comprises a second screw rod rotationally connected to the second top plate at the top end and a first screw pipe rotationally connected to the second support plate at the bottom end, and the bottom end of the second screw rod is screwed into the top end of the first screw pipe.

[0014] The inner frame paper folding device has the following advantages:

[0015] The two first base areas of the inner frame paper are respectively placed on the two conveying members, and since the distance between the two conveying members gradually decreases from the paper conveying end to the paper forming end, the two first base areas move towards the close direction when the two conveying members convey the two first base areas from the paper conveying end to the paper forming end, the first lifting member lifts the first folding area upward to form the middle spacer layer, and the second lifting member lifts the second folding area upward to form the side protruding layer, thereby completing the folding of the inner frame paper, and the structure is simple and the operation is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In these drawings, like reference numerals are used to represent similar elements. The drawings in the following description are some embodiments of the present application, not all embodiments. For those of ordinary skill in the art, other drawings can be obtained from these drawings without creative labor.

[0017] Figure 1 A structural schematic diagram of an inner frame paper folding device according to an embodiment of the present application;

[0018] Figure 2 A structural schematic diagram of an inner frame paper folding device according to an embodiment of the present application, in which the first limiting member is omitted;

[0019] Figure 3 A structural schematic diagram of an inner frame paper folding device according to an embodiment of the present application, in which the first limiting member and the second lifting member are omitted;

[0020] Figure 4 A structural schematic diagram of a first mounting plate in an inner frame paper folding device according to an embodiment of the present application;

[0021] Figure 5 A structural schematic diagram of a second lifting member in an inner frame paper folding device according to an embodiment of the present application;

[0022] Figure 6 A structural schematic diagram of an inner frame paper folding device according to an embodiment of the present application, in which the inner frame paper is not folded;

[0023] Figure 7 A structural schematic diagram of an inner frame paper folding device according to an embodiment of the present application, in which the inner frame paper is folded.

[0024] In the figure: 1-first top-up piece, 11-first top plate, 12-first support plate, 2-conveying piece, 21-first conveying roller, 22-second conveying roller, 23-synchronous belt, 24-first driving structure, 241-first gear, 242-fourth rotating shaft, 243-second gear, 244-third gear, 25-first rotating shaft, 26-second rotating shaft, 3-first limiting piece, 31-first compression roller, 32-third rotating shaft, 33-first adjusting structure, 331-first connecting rod, 332-first screw rod, 333-second spring, 334-second plug-in rod, 335-first spring, 336-first plug-in rod, 4-second top-up piece, 41-first guide plate, 42-second top plate, 43-second support plate, 44-second screw rod, 45-first screw pipe, 5-supporting piece, 51-first mounting plate, 511-first connecting groove, 512-first plug-in groove, 513-second plug-in groove, 52-bottom plate, 53-strut, 6-inner frame paper, 61-first folding area, 62-first base area, 63-second folding area, 64-first folding line, 65-second folding line, 66-third folding line, 67-intermediate spacing layer, 68-side protruding layer. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other in any manner without conflict.

[0026] Please refer to Figures 1-7The inner frame paper folding device of the embodiment of the present application is used to fold the inner frame paper 6, and comprises a first lifting piece 1, two conveying pieces 2 symmetrically arranged on both sides of the first lifting piece 1, a plurality of first limiting pieces 3 arranged above the conveying pieces 2 along the conveying direction of each conveying piece 2, and two second lifting pieces 4 symmetrically arranged on both sides of the two conveying pieces 2. The distance between the two conveying pieces 2 gradually decreases from the paper conveying end to the paper forming end. The inner frame paper 6 comprises a first folding area 61 in the middle, two first base areas 62 symmetrically arranged on both sides of the first folding area 61, and two second folding areas 63 symmetrically arranged on both sides of the two first base areas 62. The first limiting pieces 3 are used to limit the upper side of the first base area 62. The two conveying pieces 2 are used to convey the two first base areas 62 from the paper conveying end to the paper forming end respectively, so that the two first base areas 62 move towards each other. The first lifting piece 1 is used to lift the first folding area 61 upwards to form a middle spacer layer 67. The second lifting piece 4 is used to lift the second folding area 63 upwards to form a side protruding layer 68.

[0027] Here, the inner frame paper 6 further comprises a first folding line 64 coinciding with the axis of the first folding area 61, a second folding line 65 connected to the first folding area 61 and the first base area 62 at both ends, and a third folding line 66 connected to the first base area 62 and the second folding area 63 at both ends. Since there are two first base areas 62, there are two second folding lines 65, and two third folding lines 66. The two first base areas 62 are symmetrically arranged about the first folding line 64, and the two second folding areas 63 are symmetrically arranged about the first folding line 64. The two conveying pieces 2 are symmetrically arranged about the axis of the first lifting piece 1, and the two second lifting pieces 4 are symmetrically arranged about the axis of the first lifting piece 1. The first folding line 64 can be aligned with the axis of the first lifting piece 1, the first folding area 61 is aligned with the first lifting piece 1, the two first base areas 62 are respectively aligned with the two conveying pieces 2, and the two second folding areas 63 are respectively aligned with the two second lifting pieces 4. One end of the first lifting piece 1 can be recessed and arranged inside the paper conveying end of the conveying piece 2, that is, one end of the first lifting piece 1 is not aligned with the paper conveying end of the conveying piece 2. The conveying piece 2 first conveys the first base area 62. After conveying the first base area 62 for a distance, the first lifting piece 1 folds the first folding area 61 to form the middle spacer layer 67. The second lifting piece 4 can be arranged close to the paper forming end of the conveying piece 2. The two second lifting pieces 4 are arranged in parallel, the axis of the second lifting piece 4 is parallel to the axis of the first lifting piece 1, and the second lifting piece 4 lifts the second folding area 63 to form the side protruding layer 68 when the conveying piece 2 conveys the first base area 62 to the paper forming end. The two conveying pieces 2 convey the first base area 62 respectively, the first lifting piece 1 lifts the first folding area 61, and the two second lifting pieces 4 lift the two second folding areas 63 respectively.

[0028] As one of the inner frame paper folding devices in the embodiment, the support 5 can be further provided, the conveying member 2 is rotatably connected to the support 5, the first lifting member 1, the second lifting member 4 and the first limiting member 3 are respectively connected to the support 5, the support 5 comprises two first mounting plates 51 arranged in parallel, the conveying member 2 comprises a first conveying roller 21, a second conveying roller 22, a synchronous belt 23 sleeved on the outer periphery of the first conveying roller 21 and the outer periphery of the second conveying roller 22 respectively, a first driving structure 24 for driving a first rotating shaft 25, the first rotating shaft 25 sleeved on the inner side of the first conveying roller 21, and a second rotating shaft 26 sleeved on the inner side of the second conveying roller 22, the first rotating shaft 25 and the second rotating shaft 26 are respectively rotatably connected to the first mounting plate 51.

[0029] Specifically, the support 5 further comprises a bottom plate 52 connected to the two first mounting plates 51 respectively at two ends, and a support column 53 connected to the first mounting plate 51 respectively at two ends. The first rotating shaft 25 on one conveying member 2 is rotatably connected to the first end of one first mounting plate 51, and the second rotating shaft 26 is rotatably connected to the second end of one first mounting plate 51. The first rotating shaft 25 on the other conveying member 2 is rotatably connected to the first end of the other first mounting plate 51, and the second rotating shaft 26 is rotatably connected to the second end of the other first mounting plate 51. The other ends of the first rotating shafts 25 of the two conveying members 2 are connected to each other, so that the two first rotating shafts 25 form an integral structure. The other ends of the second rotating shafts 26 of the two conveying members 2 are connected to each other, so that the two second rotating shafts 26 form an integral structure. The first driving structure 24 drives one first rotating shaft 25, so that the two conveying members 2 can be driven at the same time. The first rotating shaft 25 and the second rotating shaft 26 can be rotatably connected to the first mounting plate 51 through bearings. The first driving structure 24 can comprise a first motor, a first gear 241, a fourth rotating shaft 242, a second gear 243 protruding from one side of the first mounting plate 51 and sleeved on the first rotating shaft 25, and the fourth rotating shaft 242 is sleeved in the first gear 241. One end of the fourth rotating shaft 242 is connected to the motor shaft of the first motor, and the other end is rotatably connected to the first mounting plate 51. The second gear 243 is engaged with the first gear 241. The first driving structure 24 can further comprise a third gear 244 and a fifth rotating shaft. The fifth rotating shaft is sleeved in the third gear 244. One end of the fifth rotating shaft is rotatably connected to the first mounting plate 51. The third gear 244 is engaged with the first gear 241 and the second gear 243 at two ends, so as to realize the power transmission from the first gear 241 to the second gear 243.

[0030] Specifically, the two synchronous belts 23 of the two conveying members 2 are arranged horizontally, and the angle between the two synchronous belts 23 is an acute angle. The synchronous belt 23 and the axis of the first lifting member 1 are arranged obliquely.

[0031] The distance between the two first limiting members 3 arranged correspondingly can gradually decrease along the direction from the paper input end to the paper forming end.

[0032] The first limiting member 3 can include a first adjusting structure 33, a first press roller 31 parallel to the plane where the synchronous belt 23 is located, and a third rotating shaft 32 connected to the first press roller 31. One end of the first adjusting structure 33 is connected to the first mounting plate 51, and the other end is connected to the third rotating shaft 32, so as to adjust the height between the third rotating shaft 32 and the synchronous belt 23.

[0033] Specifically, the first limiting member 3 above the two conveying members 2 can be symmetrically arranged. There can be six first limiting members 3. The first press roller 31 in the first limiting member 3 arranged near the paper conveying end of the conveying member 2 is one, and the first press roller 31 in the first limiting member 3 arranged near the paper forming end of the conveying member 2 is two. Along the direction from the paper input end to the paper forming end of the conveying member 2, the distance between the first press rollers 31 in the two first limiting members 3 gradually decreases. The first press roller 31 can be rotatably connected to the third rotating shaft 32 through a bearing.

[0034] The first lifting member 1 can include a first top plate 11 and a first support plate 12 connected to the first top plate 11 and the first mounting plate 51 at both ends.

[0035] Specifically, the two ends of the first support plate 12 can pass through the cavities between the two synchronous belts 23 and be connected to the two first mounting plates 51. The first mounting plate 51 is vertically arranged, the first support plate 12 can be perpendicular to the first mounting plate 51, and the first nail plate can be perpendicular to the first support plate 12.

[0036] The second lifting member 4 can include a second top plate 42 parallel to the plane where the top of the synchronous belt 23 is located, a first guide plate 41 connected to the second top plate 42 at one end, and a first support structure connected to the first mounting plate 51 and the second top plate 42 at both ends. The first guide plate 41 is arranged obliquely upward.

[0037] The first mounting plate 51 can include a first connecting groove 511 arranged at the top and a first plug-in groove 512 arranged on the side and in communication with the bottom end of the first connecting groove 511. The first adjusting structure 33 includes a first connecting rod 331 inserted into the first plug-in groove 512. One end of the third rotating shaft 32 is inserted into the first plug-in groove 512 and connected to the bottom end of the first connecting rod 331. The top end of the first connecting rod 331 is connected to the first mounting plate 51 when the third rotating shaft 32 moves to a preset height in the first plug-in groove 512.

[0038] The first mounting plate 51 can further comprise a second insertion groove 513 arranged in communication with the bottom of the first connecting groove 511, and a first inner thread is arranged on the sidewall of the first connecting groove 511. The first adjusting structure 33 further comprises a first spring 335, a second spring 333, a first screw rod 332, a first insertion rod 336 sleeved on the inside of the first spring 335, and a second insertion rod 334 connected to the bottom end of the first screw rod 332. The top end of the first spring 335 is inserted into the first connecting groove 511 and abuts against the first connecting rod 331. The first screw rod 332 is screwed into the first inner thread, and the bottom end of the first screw rod 332 abuts against the second spring 333. The bottom end of the second insertion rod 334 is sleeved in the second spring 333, and the second spring 333 is arranged in the first connecting groove 511 and abuts against the top end of the first connecting rod 331.

[0039] Specifically, rotating the first screw rod 332 along the first preset direction causes the first screw rod 332 to descend, and the bottom end of the first screw rod 332 presses the top end of the second spring 333. The second insertion rod 334 can limit the second spring 333 to prevent the second spring 333 from being skewed. The bottom end of the second spring 333 presses the top end of the first connecting rod 331, and the bottom end of the first connecting rod 331 presses the first spring 335. The first insertion rod 336 can limit the first spring 335 to prevent the first spring 335 from being skewed. Thus, the height of the first connecting rod 331 is adjusted downward, and the height of the third rotating shaft 32 connected to the first connecting rod 331 is adjusted downward. Since the first screw rod 332 is screwed into the first inner thread, the height of the third rotating shaft 32 can be fixed. Rotating the first screw rod 332 along the second preset direction causes the first screw rod 332 to ascend, and the bottom end of the first screw rod 332 gives up pressing the top end of the second spring 333. The second spring 333 is elongated, and the second insertion rod 334 can limit the second spring 333 to prevent the second spring 333 from being skewed. The bottom end of the second spring 333 gives up pressing the top end of the first connecting rod 331, and the bottom end of the first connecting rod 331 gives up pressing the first spring 335. The first insertion rod 336 can limit the first spring 335 to prevent the first spring 335 from being skewed. The first spring 335 drives the first connecting rod 331 to move upward, thereby adjusting the height of the first connecting rod 331 upward, and adjusting the height of the third rotating shaft 32 connected to the first connecting rod 331 upward. Since the first screw rod 332 is screwed into the first inner thread, the height of the third rotating shaft 32 can be fixed. The first insertion rod 336 can be an elastic rod that can be extended and retracted. A third insertion groove in communication with the second insertion groove 513 can be arranged in the first mounting plate 51. One end of the first insertion rod 336 can be inserted into the third insertion groove, and the first insertion rod 336 can be connected to the first spring 335. When the first spring 335 is compressed, one end of the first insertion rod 336 can move downward inside the third insertion groove.

[0040] The first guide plate 41 can be rotatably connected to the second top plate 42, so that the angle between the first guide plate 41 and the second top plate 42 is adjustable; the first guide plate 41 is fixedly connected to the second top plate 42 when the angle between the first guide plate 41 and the second top plate 42 is adjusted to a preset angle; the first support structure includes a second support plate 43 fixedly connected to the first mounting plate 51, and a telescopic lifting part, two ends of the lifting part being respectively connected to the second support plate 43 and the second top plate 42.

[0041] Specifically, the angle between the first guide plate 41 and the second top plate 42 is adjusted, so that the first guide plate 41 can better receive the second folding area 63, avoid damaging the second folding area 63, and improve the efficiency of guiding the second folding area 63 into the second top plate 42. The first guide plate 41 can be hinged to the second top plate 42.

[0042] The lifting part can include a second screw rod 44 rotatably connected to the second top plate 42 at a top end, and a first screw pipe 45 rotatably connected to the second support plate 43 at a bottom end, the second screw rod 44 being screwed to the top end of the first screw pipe 45 at a bottom end.

[0043] Specifically, by cooperating the second screw rod 44 and the first screw pipe 45, the height of the second top plate 42 is adjusted, so that the height of the second folding area 63 is adjusted. The second screw rod 44 can be rotatably connected to the second top plate 42 through a bearing, and the first screw pipe 45 can be rotatably connected to the second support plate 43 through a bearing.

[0044] Specifically, the device adopts a synchronous belt 23 with a certain included angle. When the flat inner frame paper 6 enters the device, the inner frame paper 6 is clamped and conveyed forward by the two synchronous belts 23 and the first compression roller 31 on the synchronous belt 23. Because the two synchronous belts 23 have an included angle, the synchronous belt 23 will generate an inward extrusion force during conveying. At the same time, under the action of the first top plate 11, the inner frame paper 6 is folded along the middle folding line to form an M-shaped middle separation layer 67.

[0045] Specifically, the two first mounting plates 51 and the bottom plate 52 form a box, the synchronous belt 23 forms an angle with the box, and thus the fourth rotating shaft 242 connected with the first rotating shaft 25 and the first gear 241 is connected by a universal coupling to transmit power. The first pressing roller 31 is parallel to the conveying member 2, and the first pressing roller 31 and the supporting member 5 are connected by the first adjusting structure 33 and the third rotating shaft 32. The first screw 332 is screwed at different positions on the first internal thread, so as to adjust the elastic force of the second spring 333 and the first spring 335, ensure the appropriate pressure of the first pressing roller 31 on the first base area 62 of the inner frame paper 6, keep the clamping force of the first pressing roller 31 on both sides of the inner frame paper 6 balanced, prevent the inner frame paper 6 from deviating during the conveying process, and protect the small edges of the inner frame paper 6 on both sides of the first pressing roller 31 from being wrinkled. When the inner frame paper 6 passes through the second top plate 42, the inner frame paper 6 is folded to form an M shape. The device realizes mechanized production, reduces labor costs, and improves packaging efficiency and quality.

[0046] The above-described content can be implemented alone or in various combinations, and these variations are within the scope of protection of the present application.

[0047] It should be noted that in the description of the present application, the terms "upper end", "lower end", "bottom end" indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device containing a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "includes one" does not exclude the presence of another identical element in the process, method, article or device that includes the element.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An inner frame paper folding device for folding an inner frame paper (6), characterized in that: The first top-up piece (1), two conveying pieces (2) symmetrically arranged on both sides of the first top-up piece (1), a plurality of first limiting pieces (3) arranged above the conveying piece (2) along the conveying direction of each conveying piece (2), two second top-up pieces (4) symmetrically arranged on both sides of the two conveying pieces (2), the distance between the two conveying pieces (2) gradually decreases from the paper conveying end to the paper forming end; the inner frame paper (6) comprises a first folding area (61) located in the middle, two first base areas (62) symmetrically arranged on both sides of the first folding area (61), and a second folding area (63) symmetrically arranged on both sides of the two first base areas (62); the first limiting piece (3) is used to limit the upper side of the first base area (62), and the two conveying pieces (2) are used to convey the two first base areas (62) from the paper conveying end to the paper forming end respectively, so that the two first base areas (62) move towards the approaching direction; the first top-up piece (1) is used to top up the first folding area (61) to form a middle spacer layer (67), and the second top-up piece (4) is used to top up the second folding area (63) to form a side protruding layer (68); further comprising a support piece (5), the conveying piece (2) is rotatably connected to the support piece (5), the first top-up piece (1), the second top-up piece (4) and the first limiting piece (3) are respectively connected to the support piece (5), the support piece (5) comprises two first mounting plates (51) arranged in parallel, the conveying piece (2) comprises a first conveying roller (21), a second conveying roller (22), a synchronous belt (23) sleeved on the outer periphery of the first conveying roller (21) and the outer periphery of the second conveying roller (22) respectively, a first driving structure (24) for driving a first rotating shaft (25), the first rotating shaft (25) sleeved on the inner side of the first conveying roller (21), and the second rotating shaft (26) sleeved on the inner side of the second conveying roller (22), the first rotating shaft (25) and the second rotating shaft (26) are rotatably connected to the first mounting plate (51); the second top-up piece (4) comprises a second top plate (42) parallel to the top plane of the synchronous belt (23), a first guide plate (41) connected to one end of the second top plate (42), and a first support structure connected to the first mounting plate (51) and the second top plate (42) at both ends, the first guide plate (41) is arranged obliquely upward; the first guide plate (41) is rotatably connected to the second top plate (42), so that the angle between the first guide plate (41) and the second top plate (42) can be adjusted; the first guide plate (41) is fixedly connected to the second top plate (42) when the angle between the first guide plate (41) and the second top plate (42) is adjusted to a preset angle; the first support structure comprises a second support plate (43) fixedly connected to the first mounting plate (51) and a telescopic lifting part, both ends of the lifting part are connected to the second support plate (43) and the second top plate (42) respectively.

2. An inner frame paper folding apparatus as claimed in claim 1, characterized in that: The distance between the two first limiting pieces (3) arranged correspondingly gradually decreases along the direction from the paper input end to the paper forming end.

3. An inner frame paper folding apparatus according to claim 1 or 2, characterized in that: The first limiting piece (3) comprises a first adjusting structure (33), a first press roller (31) with a bottom parallel to a plane where a top of the synchronous belt (23) is located, and a third rotating shaft (32) rotatably connected to the first press roller (31), wherein one end of the first adjusting structure (33) is connected to the first mounting plate (51), and the other end is connected to the third rotating shaft (32), so as to adjust a height between the third rotating shaft (32) and the synchronous belt (23).

4. An inner frame paper folding apparatus according to claim 1 or 2, wherein: The first lifting piece (1) comprises a first top plate (11) and a first support plate (12) connected to the first top plate (11) and the first mounting plate (51) respectively.

5. An inner frame paper folding apparatus as claimed in claim 3, wherein: The first mounting plate (51) comprises a first connecting groove (511) arranged on a top, and a first plug-in groove (512) arranged on a side and in communication with a bottom of the first connecting groove (511), the first adjusting structure (33) comprises a first connecting rod (331) inserted into the first plug-in groove (512), one end of the third rotating shaft (32) is inserted into the first plug-in groove (512) and connected to the first connecting rod (331), and a top end of the first connecting rod (331) is connected to the first mounting plate (51) when the third rotating shaft (32) moves to a preset height in the first plug-in groove (512).

6. An inner frame paper folding apparatus as claimed in claim 5, wherein: The first mounting plate (51) further comprises a second plug-in groove (513) arranged on a bottom and in communication with the bottom of the first connecting groove (511), a first internal thread is arranged on a side wall of the first connecting groove (511), the first adjusting structure (33) further comprises a first spring (335), a second spring (333), a first screw rod (332), a first plug-in rod (336) sleeved on an inside of the first spring (335), and a second plug-in rod (334) connected to a bottom end of the first screw rod (332), a top end of the first spring (335) is inserted into the first connecting groove (511) and abuts against the first connecting rod (331), the first screw rod (332) is screwed into the first internal thread, a bottom end of the first screw rod (332) abuts against the second spring (333), a bottom end of the second plug-in rod (334) is sleeved on the second spring (333), and the second spring (333) is arranged in the first connecting groove (511) and abuts against the top end of the first connecting rod (331).

7. An inner frame paper folding apparatus as claimed in claim 1, wherein: The lifting part comprises a second screw rod (44) rotatably connected to a top end of a second top plate (42), and a first screw pipe (45) rotatably connected to a bottom end of a second support plate (43), wherein a bottom end of the second screw rod (44) is screwed into a top end of the first screw pipe (45).

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