Double-hole punching machine

Abstract

A double-hole perforating machine comprises a base, a die holder, a connecting seat, a gland and a stamping knife. First mounting grooves are formed in the upper end face of the base. An upper fixing plate and a lower fixing plate which are arranged in parallel are arranged on one side of the die holder, and the lower fixing plate is clamped in the first mounting groove through a first clamping mechanism; a containing cavity with an upper opening and a lower opening is formed in the connecting base, and the upper fixing plate is clamped to the opening in the lower end of the containing cavity through a second clamping mechanism. The gland is sleeved with the containing cavity and slides up and down, a limiting ring is arranged at the lower end of the outer wall of the gland, a pressing ring is arranged at an opening in the upper end of the containing cavity in an inward protruding mode and limits upward movement of the limiting ring, and an elastic reset piece is arranged between the lower end face of the gland and the upper end face of the upper fixing plate. Compared with the prior art, the utility model has the beneficial effects that the improved assembly structure is simple, the assembly process is simple, and the product assembly operation is convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of punching tools, in particular to a double-hole punching machine. Background Art

[0002] A homemade loose-leaf book requires a puncher, which punches holes in the paper and then binds it into a loose-leaf book with loose-leaf rings. According to the needs, the puncher includes a single-hole puncher, a double-hole puncher, and a multi-hole puncher. The existing double-hole puncher structure, such as a row of holes puncher disclosed in Chinese utility model patent CN220313541U, is composed of parts such as a pressure cover, a support component, and a punching module. The assembly of these parts requires many processes and steps. For example, the pressure cover and the support component are connected by a rotating shaft, and the two ends of the rotating shaft need to be riveted. The punching module and the support component are fastened by screws. This makes the product assembly process cumbersome and the production efficiency low. Utility Model Content

[0003] The utility model provides a double-hole punching machine structure which is convenient to assemble in order to solve the above problems.

[0004] The technical solution used by the utility model to solve the above problems is: a double-hole punching machine, including a base, a mold base, a connecting base, a pressure cover and a punching knife; the upper end surface of the base is provided with a first mounting groove; one side of the mold base is provided with an upper fixing plate and a lower fixing plate arranged in parallel, a gap is provided between the upper fixing plate and the lower fixing plate to form a paper insertion slot, the upper fixing plate and the lower fixing plate are respectively coaxially provided with an upper punching hole and a lower punching hole, the lower fixing plate is clamped in the first mounting groove by a first clamping mechanism, and the upper end surface of the lower fixing plate is flush with the upper end surface of the base; the connecting base is provided with upper and lower openings The upper fixed plate is clamped at the lower opening of the accommodating cavity by a second clamping mechanism; the pressure cover is sleeved in the accommodating cavity and slides up and down, a limiting ring is provided at the lower end of the outer wall of the pressure cover, and a pressure ring is protruding inward at the upper opening of the accommodating cavity, and the pressure ring limits the upward movement of the limiting ring, and an elastic reset part is provided between the lower end surface of the pressure cover and the upper end surface of the upper fixed plate, so that the upper end of the pressure cover maintains the tendency to extend out of the accommodating cavity; the upper end of the punching knife is inserted into the connecting groove of the lower end surface of the pressure cover, and the lower end of the punching knife is located in the upper punching hole, and the pressure cover slides downward to drive the lower end of the punching knife to extend out of the upper punching hole.

[0005] After adopting the above structure, when assembling the double-hole punching machine of the utility model, the punching knife and the pressure cover are first plugged, and then the pressure cover is placed in the accommodating cavity, and the elastic reset member is placed, and then the upper fixing plate of the mold base is clamped with the accommodating cavity, and the lower fixing plate is clamped with the first mounting groove of the base. The upper fixing plate and the accommodating cavity, and the lower fixing plate and the base are clamped by a clamping mechanism, which is fast to assemble and stable to connect. Compared with the prior art, the advantage is that the improved assembly structure is simple, the assembly process is concise, and the product assembly operation is convenient.

[0006] Preferably, the first clamping mechanism includes a first clamping slot and a first clamping block, wherein the first clamping slot is arranged on the side wall of the first installation slot, the first clamping block is arranged on the edge of the lower fixing plate, and the first clamping block is plugged and matched with the first clamping slot; a first inclined surface is arranged between the upper end surface of the base and the side wall of the first installation slot, and the first inclined surface is located above the first clamping slot. During installation, the first inclined surface provides a guiding effect to the first clamping block, so that the first clamping block is conveniently inserted into the first clamping slot.

[0007] Preferably, the second clamping mechanism includes a second clamping slot and a second clamping block, the second clamping slot is arranged at the lower end of the inner wall of the accommodating cavity, the second clamping block is arranged at the edge of the upper fixing plate, and the second clamping block is plugged and matched with the second clamping slot; a second inclined surface is arranged between the lower end surface of the connecting seat and the inner wall of the accommodating cavity, and the second inclined surface is located below the second clamping slot. During installation, the second inclined surface provides a guiding effect for the second clamping block to facilitate the insertion of the second clamping block into the second clamping slot.

[0008] Preferably, a guide block is provided on the upper end surface of the upper fixed plate, a guide hole is provided in the guide block, the guide hole is coaxially connected with the upper punch hole and has the same size, the lower end of the punch is inserted into the guide hole and the upper punch hole, the elastic reset member is a spring, and the spring is sleeved on the outer periphery of the guide block. The setting of the guide block provides a guiding effect for the punch knife to move up and down and the spring to expand and contract.

[0009] Preferably, the punching knife includes a handle portion arranged at the upper end of the punching knife, the outer size of the handle portion is larger than the outer size of the punching knife, the handle portion is inserted into the connecting groove, the upper end of the spring abuts against the lower end surface of the handle, and the lower end of the spring abuts against the upper end surface of the upper fixed plate.

[0010] Preferably, a chip bin with an opening at the lower end is provided in the base, a first through hole communicating with the chip bin is provided at the bottom of the first installation slot, the first through hole corresponds to the lower part of the lower punching hole, and a bottom cover is rotatably connected to the lower opening of the chip bin; a symmetrical hinge block is provided on the bottom cover, a rotating shaft is provided on the outer side of the hinge block, an axial hole matching the rotating shaft is provided on the inner wall of the chip bin, a third inclined plane transition is provided between the lower end of the inner wall of the chip bin and the lower end surface of the base, and the third inclined plane is located below the axial hole; a stop block is provided at one end of the bottom cover away from the hinge block, a stop groove is provided in the chip bin, the stop block is clamped in the stop groove, a third clamping block is provided on the inner wall of the stop groove, and a third clamping slot is provided on the side wall of the stop block. After such arrangement, when the hinge block of the bottom cover is installed, the third inclined plane guides the rotating shaft, so that the rotating shaft is inserted into the axial hole, and after the stop block at the other end is clamped with the stop groove, the bottom cover is in a state of covering the lower opening of the chip bin.

[0011] Preferably, a positioning plate is provided on the side of the base, a second mounting groove is provided on the lower end surface of the positioning plate, a second through hole connected to the second mounting groove is provided on the positioning plate, a mounting block is inserted in the second mounting groove, a positioning column is provided on the upper end of the mounting block, and the positioning column passes through the second through hole and extends out of the positioning plate; a fourth card slot is provided on the inner wall of the second mounting groove, a fourth card block engaged with the fourth card slot is provided on the side wall of the mounting block, and notches are provided on both sides of the fourth card block. After the mounting block is inserted into the second mounting groove, the positioning column extends out of the positioning plate, and the positioning column and the base are separately injection molded, so that the two can be made in different colors.

[0012] Preferably, the side edge of the base located on the opposite side of the paper insertion slot is provided with a connection protrusion protruding upward, the upper end surface of the connection protrusion is provided with a convex rib, and the lower end surface of the connection seat is provided with an inner recess that engages with the convex rib. After such arrangement, one side of the base is connected to the connection seat, covering the back of the mold base, preventing the mold base from being exposed and affecting the integrity of the product.

[0013] Preferably, the limiting ring is provided with a slide groove, the inner wall of the accommodating cavity is provided with a guide rib extending in a vertical direction, and the guide rib is slidably connected with the slide groove, so as to prevent the gland from lateral deviation when sliding up and down. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the double-hole punching machine of the utility model.

[0015] Figure 2 It is an exploded view of the double-hole punching machine of the utility model.

[0016] Figure 3 It is a cross-sectional view of the double-hole punching machine of the utility model.

[0017] Figure 4 It is a cross-sectional view of the double-hole punching machine of the utility model from another direction.

[0018] Figure 5 It is a structural schematic diagram of the pressure cover and the connecting seat of the double-hole punching machine of the utility model.

[0019] Figure 6 It is a structural schematic diagram of a die base of a double-hole punching machine of the utility model.

[0020] Figure 7 It is a structural schematic diagram of the base of the double-hole punching machine of the utility model.

[0021] Figure 8 It is a structural schematic diagram of the mounting block of the double-hole punching machine of the utility model.

[0022] As shown in the figure:

[0023] 1. base, 10. first mounting groove, 101. first clamping groove, 102. first inclined surface, 103. first through hole, 11. chip bin, 111. shaft hole, 112. third inclined surface, 113. limiting groove, 1131. third clamping block, 12. positioning plate, 120. second mounting groove, 1201. fourth clamping groove, 121. second through hole, 13. connecting protrusion, 131. convex rib;

[0024] 2. mold base, 20. paper insertion slot, 21. upper fixing plate, 210. upper punching hole, 211. second clamping block, 212. guide block, 2120. guide hole, 22. lower fixing plate, 220. lower punching hole, 221. first clamping block;

[0025] 3. Connecting seat, 30. Accommodating cavity, 301. Pressing ring, 302. Second slot, 303. Second inclined surface, 304. Guide rib, 31. Concave;

[0026] 4. gland, 40. connecting groove, 41. limiting ring, 410. slide groove;

[0027] 5. punching knife, 51. knife handle;

[0028] 6. Elastic reset member;

[0029] 7. bottom cover, 71. hinge block, 711. rotating shaft, 72. limit block, 721. third slot;

[0030] 8. mounting block, 81. positioning column, 82. fourth clamping block, 820. notch. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0032] like Figures 1 to 4 As shown, a double-hole punching machine includes a base 1, a die base 2, a connecting base 3, a pressure cover 4 and a punching knife 5. An upper fixing plate 21 and a lower fixing plate 22 are arranged in parallel on one side of the die base 2, a gap is arranged between the upper fixing plate 21 and the lower fixing plate 22 to form a paper insertion slot 20, and an upper punching hole 210 and a lower punching hole 220 are coaxially arranged on the upper fixing plate 21 and the lower fixing plate 22, respectively.

[0033] The upper end surface of the base 1 is provided with a first mounting groove 10, and the lower fixing plate 22 is clamped in the first mounting groove 10 through a first clamping mechanism, and the upper end surface of the lower fixing plate 22 is flush with the upper end surface of the base 1. The first clamping mechanism includes a first clamping groove 101 and a first clamping block 221. The first clamping groove 101 is provided on the side wall of the first mounting groove 10, and the first clamping block 221 is provided on the edge of the lower fixing plate 22. The first clamping block 221 is plugged and matched with the first clamping groove 101. The lower end surface of the first clamping block 221 is an inclined surface, and the upper end surface is a plane. A first inclined surface 102 is provided between the upper end surface of the base 1 and the side wall of the first mounting groove 10, and the first inclined surface 102 is located above the first clamping groove 101. During installation, the first inclined surface 102 cooperates with the lower end surface of the first card block 221 to provide a guiding effect for the first card block 221 to facilitate the first card block 221 to be inserted into the first card slot 101. After the first card block 221 is inserted into the first card slot 101, the upper end surface of the first card block 221 abuts against the upper slot wall of the first card slot 101.

[0034] The connection base 3 is provided with a receiving chamber 30 with upper and lower openings, and the upper fixing plate 21 is connected to the lower opening of the receiving chamber 30 through a second clamping mechanism. The second clamping mechanism includes a second clamping groove 302 and a second clamping block 211. The second clamping groove 302 is provided at the lower end of the inner wall of the receiving chamber 30, and the second clamping block 211 is provided at the edge of the upper fixing plate 21. The second clamping block 211 is plugged and matched with the second clamping groove 302. A second inclined surface 303 is provided between the lower end surface of the connection base 3 and the inner wall of the receiving chamber 30, and the second inclined surface 303 is located below the second clamping groove 302. The upper end surface of the second card block 211 is an inclined surface, and the lower end surface is a plane. During installation, the second inclined surface 303 cooperates with the upper end surface of the second card block 211 to provide a guiding effect for the second card block 211, so that the second card block 211 is inserted into the second card slot 302. After the second card block 211 is inserted into the second card slot 302, the lower end surface of the second card block 211 abuts against the lower slot wall of the second card slot 302.

[0035] The gland 4 is sleeved in the accommodating chamber 30 and slides up and down. A limit ring 41 is provided at the lower end of the outer wall of the gland 4, and a pressure ring 301 is protruding inward from the upper opening of the accommodating chamber 30. The cross sections of the gland 4 and the connecting seat 3 are both circular. The outer diameter of the limit ring 41 is larger than the inner diameter of the pressure ring 301. The pressure ring 301 is located above the limit ring 41, and the pressure ring 301 limits the upward movement of the limit ring 41. An elastic reset member 6 is provided between the lower end surface of the gland 4 and the upper end surface of the upper fixing plate 21, so that the upper end of the gland 4 maintains the tendency to extend out of the accommodating chamber 30.

[0036] The upper end of the punching knife 5 is inserted into the connecting groove 40 on the lower end surface of the pressure cover 4, and the lower end of the punching knife 5 is located in the upper punching hole 210. The pressure cover 4 slides downward to drive the lower end of the punching knife 5 to extend out of the upper punching hole 210.

[0037] The upper end surface of the upper fixed plate 21 is provided with a guide block 212, and a guide hole 2120 is provided in the guide block 212. The guide hole 2120 is coaxially connected with the upper punch hole 210 and has the same size. The lower end of the punch 5 is inserted into the guide hole 2120 and the upper punch hole 210. The cross section of the punch of the double-hole punch of the utility model is mushroom-shaped. The upper punch hole 210, the lower punch hole 220 and the guide hole 2120 match the cross section of the punch. The mushroom-shaped loose-leaf ring design saves the trouble of opening and closing ordinary loose-leaf rings, and it is more worry-free to replace paper. The elastic reset member 6 is a spring, and the spring is sleeved on the outer periphery of the guide block 212. The setting of the guide block 212 provides a guiding effect for the up and down movement of the punch and the expansion and contraction of the spring.

[0038] The punching knife 5 includes a handle portion 51 disposed at the upper end of the punching knife 5, the handle portion 51 is circular, and the outer dimension of the handle portion 51 is larger than the outer dimension of the punching knife 5. The handle portion 51 is inserted into the connecting groove 40, the upper end of the spring abuts against the lower end surface of the handle portion 51, and the lower end of the spring abuts against the upper end surface of the upper fixing plate 21.

[0039] The base 1 is provided with a chip bin 11 with an opening at the lower end, and the bottom of the first mounting groove 10 is provided with a first through hole 103 connected with the chip bin 11. The first through hole 103 corresponds to the lower part of the lower punch hole 220, and the lower end opening of the chip bin 11 is rotatably connected with the bottom cover 7. The bottom cover 7 is provided with a symmetrical hinge block 71, and a rotating shaft 711 is provided on the outer side of the hinge block 71. The inner wall of the chip bin 11 is provided with an axial hole 111 that matches the rotating shaft 711. A third inclined surface 112 is provided between the lower end of the inner wall of the chip bin 11 and the lower end surface of the base 1 for transition, and the third inclined surface 112 is located below the axial hole 111. A stop block 72 is provided at one end of the bottom cover 7 away from the hinge block 71, and a stop groove 113 is provided in the chip bin 11. The stop block 72 is clamped in the stop groove 113, and a third clamping block 1131 is provided on the inner wall of the stop groove 113. A third clamping groove 721 is provided on the side wall of the stop block 72. When the hinge block of the bottom cover 7 is installed, the third inclined surface 112 guides the shaft 711 to facilitate the insertion of the shaft 711 into the shaft hole 111. After the limit block at the other end is engaged with the limit groove, the bottom cover is in a state of covering the lower opening of the chip bin.

[0040] A positioning plate 12 is provided on the side of the base 1, a second mounting groove 120 is provided on the lower end surface of the positioning plate 12, a second through hole 121 communicating with the second mounting groove 120 is provided on the positioning plate 12, a mounting block 8 is inserted in the second mounting groove 120, a positioning column 81 is provided on the upper end of the mounting block 8, and the positioning column 81 passes through the second through hole 121 and extends out of the positioning plate 12. A fourth clamping groove 1201 is provided on the inner wall of the second mounting groove 120, and a fourth clamping block 82 engaged with the fourth clamping groove 1201 is provided on the side wall of the mounting block 8, the upper end surface of the fourth clamping block 82 is an inclined surface, and the lower end surface is a plane, and the side wall of the mounting block 8 is provided with notches 820 on both sides of the fourth clamping block 82, so that the fourth clamping block 82 has a certain elasticity, which is convenient for clamping into the fourth clamping groove 1201 during installation. After the mounting block 8 is inserted into the second mounting groove 120, the positioning column 81 extends out of the positioning plate 12, and the lower end surface of the fourth clamping block 82 abuts against the lower groove wall of the fourth clamping groove 1201, and the mounting block 8 is fixed in the second mounting groove 120 and is not removed. After this arrangement, the positioning column 12 and the base 1 can be separately injection molded, so that the two can be made in different colors.

[0041] The side edge of the base 1 located on the opposite side of the paper insertion slot 20 is provided with a connection protrusion 13 protruding upward, the upper end surface of the connection protrusion 13 is provided with a convex rib 131, and the lower end surface of the connection seat 3 is provided with an inner recess 31 that is engaged with the convex rib 131. After the arrangement is made in this way, one side of the base 1 is connected to the connection seat 3, covering the back side of the mold base 2, so as to prevent the mold base 2 from being exposed and affecting the integrity of the product.

[0042] A sliding groove 410 is provided on the limiting ring 41 , and a guide rib 304 extending in a vertical direction is provided on the inner wall of the accommodating cavity 30 . The guide rib 304 is slidably connected to the sliding groove 410 .

[0043] The double-hole punching machine of the utility model has a simple assembly structure and easy assembly operation. During assembly, first connect the punching knife 5 with the pressure cover 4, insert the handle part 41 into the connecting groove 40, then place the pressure cover 4 into the accommodating cavity 30, then put the elastic reset member 6 spring sleeve on the punching knife 5, then snap-fit ​​the upper fixed plate 21 of the die base 2 with the accommodating cavity 30, the lower end of the punching knife 5 corresponds to the guide hole 2120 of the upper fixed plate 21, and then snap-fit ​​the lower fixed plate 22 with the first mounting groove 10 of the base 1. Then plug the mounting block 8 into the second mounting groove 120, and plug the bottom cover 7 into the lower end outlet of the chip bin 11. The connection and assembly between the die base 2 and the connecting base 3 and the base 1 are all snap-fitted, and the process is simple and the assembly is convenient.

Claims

1. A double-hole punching machine, characterized in that: It comprises a base (1), a mold base (2), a connecting base (3), a pressure cover (4) and a punch (5); The upper end surface of the base (1) is provided with a first mounting groove (10); An upper fixing plate (21) and a lower fixing plate (22) are arranged in parallel on one side of the mold base (2); a gap is provided between the upper fixing plate (21) and the lower fixing plate (22) to form a paper insertion slot (20); an upper punching hole (210) and a lower punching hole (220) are coaxially arranged on the upper fixing plate (21) and the lower fixing plate (22), respectively; the lower fixing plate (22) is clamped in the first installation slot (10) by a first clamping mechanism, and the upper end surface of the lower fixing plate (22) is flush with the upper end surface of the base (1); The connection seat (3) is provided with a receiving cavity (30) with upper and lower openings, and the upper fixing plate (21) is clamped at the lower opening of the receiving cavity (30) through a second clamping mechanism; The pressure cover (4) is sleeved in the accommodating chamber (30) and slides up and down. A limiting ring (41) is provided at the lower end of the outer wall of the pressure cover (4). A pressure ring (301) is protruding inwardly at the upper end opening of the accommodating chamber (30). The pressure ring (301) limits the upward movement of the limiting ring (41). An elastic reset member (6) is provided between the lower end surface of the pressure cover (4) and the upper end surface of the upper fixing plate (21), so that the upper end of the pressure cover (4) maintains a tendency to extend out of the accommodating chamber (30). The upper end of the punching knife (5) is inserted into the connecting groove (40) on the lower end surface of the pressure cover (4), and the lower end of the punching knife (5) is located in the upper punching hole (210). The pressure cover (4) slides downward to drive the lower end of the punching knife (5) to extend out of the upper punching hole (210).

2. The double-hole punching machine according to claim 1, characterized in that: The first clamping mechanism comprises a first clamping slot (101) and a first clamping block (221); the first clamping slot (101) is arranged on a side wall of the first mounting slot (10); the first clamping block (221) is arranged on an edge of a lower fixing plate (22); the first clamping block (221) is plugged into and matched with the first clamping slot (101); a first inclined surface (102) is arranged between an upper end surface of the base (1) and a side wall of the first mounting slot (10); the first inclined surface (102) is located above the first clamping slot (101).

3. The double-hole punching machine according to claim 1, characterized in that: The second clamping mechanism comprises a second clamping groove (302) and a second clamping block (211); the second clamping groove (302) is arranged at the lower end of the inner wall of the accommodating cavity (30); the second clamping block (211) is arranged at the edge of the upper fixing plate (21); the second clamping block (211) is plugged into and matched with the second clamping groove (302); a second inclined surface (303) is arranged between the lower end surface of the connecting seat (3) and the inner wall of the accommodating cavity (30); the second inclined surface (303) is located below the second clamping groove (302).

4. The double-hole punching machine according to claim 1, characterized in that: The upper end surface of the upper fixed plate (21) is provided with a guide block (212), a guide hole (2120) is provided in the guide block (212), the guide hole (2120) is coaxially connected with the upper punch hole (210) and has the same size, the lower end of the punching knife (5) is inserted into the guide hole (2120) and the upper punch hole (210), and the elastic reset member (6) is a spring, and the spring is sleeved on the outer periphery of the guide block (212).

5. The double-hole punching machine according to claim 4, characterized in that: The punching knife (5) comprises a handle portion (51) arranged at the upper end of the punching knife (5), the outer dimensions of the handle portion (51) are larger than the outer dimensions of the punching knife (5), the handle portion (51) is inserted into the connecting groove (40), the upper end of the spring abuts against the lower end surface of the handle portion (51), and the lower end of the spring abuts against the upper end surface of the upper fixing plate (21).

6. The double-hole punching machine according to claim 1, characterized in that: The base (1) is provided with a chip bin (11) with an opening at the lower end; the bottom of the first mounting groove (10) is provided with a first through hole (103) communicating with the chip bin (11); the first through hole (103) corresponds to the lower part of the lower punch hole (220); the lower opening of the chip bin (11) is rotatably connected to a bottom cover (7); a symmetrical hinge block (71) is provided on the bottom cover (7); a rotating shaft (711) is provided on the outer side of the hinge block (71); and an inner wall of the chip bin (11) is provided with an axial hole (111) cooperating with the rotating shaft (711). A third inclined surface (112) is provided between the lower end of the inner wall of the chip bin (11) and the lower end surface of the base (1) for transition, and the third inclined surface (112) is located below the shaft hole (111); a limit block (72) is provided at one end of the bottom cover (7) away from the hinge block (71), a limit groove (113) is provided in the chip bin (11), the limit block (72) is clamped in the limit groove (113), a third clamping block (1131) is provided on the inner wall of the limit groove (113), and a third clamping groove (721) is provided on the side wall of the limit block (72).

7. The double-hole punching machine according to claim 1, characterized in that: A positioning plate (12) is provided on the side of the base (1), a second mounting groove (120) is provided on the lower end surface of the positioning plate (12), a second through hole (121) connected to the second mounting groove (120) is provided on the positioning plate (12), a mounting block (8) is inserted into the second mounting groove (120), a positioning column (81) is provided on the upper end of the mounting block (8), and the positioning column (81) passes through the second through hole (121) and extends out of the positioning plate (12); a fourth clamping groove (1201) is provided on the inner wall of the second mounting groove (120), a fourth clamping block (82) clamped with the fourth clamping groove (1201) is provided on the side wall of the mounting block (8), and notches (820) are provided on both sides of the fourth clamping block (82) on the side wall of the mounting block (8).

8. The double-hole punching machine according to claim 1, characterized in that: A connecting protrusion (13) is protruding upwards on the side of the base (1) located opposite to the paper insertion slot (20); a convex rib (131) is provided on the upper end surface of the connecting protrusion (13); and an inner recess (31) is provided on the lower end surface of the connecting seat (3) for engaging with the convex rib (131).

9. The double-hole punching machine according to claim 1, characterized in that: The limiting ring (41) is provided with a sliding groove (410), and the inner wall of the accommodating cavity (30) is provided with a guide rib (304) extending in a vertical direction, and the guide rib (304) is slidably connected to the sliding groove (410).

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