Center lock art knife

Abstract

The utility model discloses a center lock art knife which comprises a shell and a blade, a knife groove used for containing the blade is formed in the shell, the cross section of the knife groove is in a C shape, a knife holder detachably connected with the blade is arranged at one end of the knife groove, and the bottom of the knife holder is located in the knife groove and connected with the knife groove in a sliding mode. A spring piece and a push button are arranged at the top of the tool apron, the spring piece is located between the push button and the tool apron and detachably and fixedly connected with the tool apron, the tool apron is limited in the tool groove through the spring piece, the push button is located outside the tool groove, the push button is in sliding connection with the tool apron and provided with a driving part for driving the spring piece to deform, and a locking switch is in sliding connection with the push button. A locking groove matched with the locking switch is formed in the knife holder, the locking switch is matched with or separated from the locking groove after sliding relative to the push button, and a knife outlet matched with the blade is formed in the other end of the knife groove. The utility model has the beneficial effects that the user experience is improved, and the purpose of improving the safety performance is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of art knives, in particular to a central lock art knife. Background Art

[0002] An art knife, also commonly known as a carving knife or wallpaper knife, is a knife used for art and handicrafts. It is mostly composed of a plastic handle and a blade, and is of a pull-out type. There are also a few with metal handles.

[0003] Chinese Patent No. CN107160436A, with a publication date of September 15, 2017, discloses an art knife, which includes a knife holder, a blade, a push-pull block and a limit block. The knife holder is a hollow frame structure, and its upper surface is provided with a chute that matches the structure of the push-pull block. The chute is a long strip shape with one end open, and a limit block is provided at the open end of the chute. The blade is located inside the knife holder. One end of the blade is connected to the push-pull block, and the push-pull block can drive the blade to slide back and forth along the chute. One end of the knife holder is detachably connected with a limit block, and the other end is provided with a clamping block. A limit groove that matches the structure of the blade is provided at the middle position of the clamping block. One end of the clamping block is fixedly sleeved inside the knife holder, and the other end protrudes out of the outer end of the knife holder. A magnet is fixedly provided on the upper surface of the part that protrudes out of the knife holder. A measuring device is provided at the lower end of the clamping block. The measuring device includes a measuring ruler, a strip-shaped through groove and a slider. The measuring ruler is sleeved inside the knife holder. The strip-shaped through groove is located on the upper surface of the knife holder. The slider passes through the strip-shaped through groove from the outer end of the knife holder and is fixedly connected to the measuring ruler.

[0004] In the above patent, the push-pull block can drive the blade to slide back and forth along the chute to realize the telescopic movement of the blade. However, in the process of use, there are the following deficiencies: the blade cannot be fixed, which on the one hand easily causes the blade to slide during use, resulting in poor user experience, and at the same time there are certain operation risks for both people and objects, which is not conducive to safety; on the other hand, young children often push out the blade to play out of curiosity, so it does not play a good protective role for young children and is not conducive to safety. Summary of the Utility Model

[0005] The utility model is to overcome the deficiency that the use of art knives in the prior art is not conducive to safety, and provides a central lock art knife that is conducive to improving safety performance.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A center-lock utility knife, which comprises a housing and a blade. A knife groove for accommodating the blade is provided on the housing. The cross-sectional shape of the knife groove is C-shaped. A knife seat detachably connected to the blade is provided at one end of the knife groove. The bottom of the knife seat is located in the knife groove and is slidably connected to the knife groove. A spring piece and a push button are respectively provided at the top of the knife seat. The spring piece is located between the push button and the knife seat and is detachably and fixedly connected to the knife seat. The knife seat is limited in the knife groove by the spring piece. The push button is located outside the knife groove. The push button is slidably connected to the knife seat and is provided with a driving portion for driving the spring piece to deform. A locking switch is slidably connected to the push button. A locking groove matching the locking switch is provided on the knife seat. The locking switch cooperates with or separates from the locking groove after sliding relative to the push button. An exit opening matching the blade is provided at the other end of the knife groove.

[0008] A knife groove for accommodating the blade is provided on the housing. The cross-sectional shape of the knife groove is C-shaped. A knife seat detachably connected to the blade is provided at one end of the knife groove. The bottom of the knife seat is located in the knife groove and is slidably connected to the knife groove. A spring piece and a push button are respectively provided at the top of the knife seat. The spring piece is located between the push button and the knife seat and is detachably and fixedly connected to the knife seat. The knife seat is limited in the knife groove by the spring piece. The push button is located outside the knife groove. The push button is slidably connected to the knife seat and is provided with a driving portion for driving the spring piece to deform. A locking switch is slidably connected to the push button. A locking groove matching the locking switch is provided on the knife seat. The locking switch cooperates with or separates from the locking groove after sliding relative to the push button. An exit opening matching the blade is provided at the other end of the knife groove. The locking switch is locked in matching with the locking groove on the knife seat, so that the push button cannot slide relative to the knife seat, and further the push button cannot drive the spring piece to deform through the driving portion to release the limit on the knife seat. Finally, the knife seat cannot drive the blade to slide in the knife groove, so as to play a positioning and locking role both when the blade is in use or when the blade is stored in the knife groove, improving the user experience and achieving the purpose of facilitating the improvement of safety performance; on the contrary, the operator can release the lock by sliding the locking switch to separate the locking switch from the locking groove on the knife seat, and the operation is convenient and fast.

[0009] Preferably, a guiding inclined surface is provided at the bottom of the other end of the knife groove. The shape of the guiding inclined surface is an arc arching from the bottom of the knife groove towards the inside of the knife groove. The bottom of the knife groove is uniformly transitioned to the exit opening through the guiding inclined surface. The depth of the knife groove is greater than the width in the same direction as the depth of the exit opening. When in use, after the operator pushes the blade out of the knife groove through the exit opening, the width setting of the exit opening limits the upper and lower surfaces of the blade, preventing the blade from shaking during use and improving the cutting accuracy and use safety of the blade.

[0010] Preferably, a mounting groove matching the locking switch is provided at the top of the push button, the locking switch is slidably connected to the mounting groove and its sliding direction is perpendicular to the sliding direction of the knife seat along the knife groove, the top of the locking switch gradually protrudes outward from its two ends toward its center, and anti-slip grooves are provided at both ends of the top of the locking switch, and a limiting cam and a locking block matching the locking groove are respectively fixed to the bottom of the locking switch, a rectangular hole is provided at the bottom of the mounting groove, the limiting cam and the locking block are both located in the rectangular hole, a limiting rib is provided on the side wall of the rectangular hole, and arc-shaped surfaces are provided on the left and right sides of the limiting rib, and the limiting rib is connected with the side wall of the rectangular hole through the arc-shaped surface to form a wavy structure, and limiting areas matching the limiting cam are formed on the left and right sides of the limiting rib. The top of the locking switch gradually bulges outward from its two ends toward its center, which is convenient for the locking switch to be toggled back and forth. At the same time, both ends of the top of the locking switch are provided with anti-slip grooves, which are beneficial to prevent the locking switch from slipping when it is toggled, and are easy to operate; the locking switch is slidably connected with the mounting groove to drive the locking block thereon to cooperate with the locking groove to lock or separate from the locking groove to unlock; the limiting convex rib is connected with the side wall of the rectangular hole through the arc surface to form a wavy structure together, which is convenient for the operator to toggle the locking switch so that the limiting convex shaft can smoothly slide into the limiting areas on the left and right sides of the limiting convex rib, which is convenient for operation; the limiting areas on the left and right sides of the limiting convex rib respectively limit the locking switch in the locked or unlocked state through the limiting convex shaft.

[0011] Preferably, a protrusion is provided on the top of the knife seat, and the protrusion is located in the open end of the knife groove, and the bottom of the protrusion is fixedly connected to the knife seat, and the top of the protrusion is located outside the knife groove and is provided with a groove, and the spring sheet is detachably installed in the groove, and the push button covers the open end of the groove, and the push button is slidably connected to the open end of the groove and its sliding direction is parallel to the sliding direction of the knife seat along the knife groove, and a baffle and a U-shaped block are respectively fixed in the groove, and the baffle and the length direction of the knife groove are parallel to each other, and the locking groove is formed in the U-shaped block, and the open end of the locking groove is close to the baffle and a channel is formed between the baffle and the baffle for easy passage of the locking block, and the bottom of the locking groove is away from the baffle, and both ends of the baffle are vertically fixed with baffles corresponding to the locking block. The position design of the open end of the lock slot makes it easy for the operator to turn the locking switch so that the lock block can be inserted into the lock slot for locking or separated from the lock slot to enter the channel; since the sliding direction of the push button is parallel to the sliding direction of the knife holder along the knife slot, and the sliding direction of the locking switch is perpendicular to the sliding direction of the knife holder along the knife slot, when the lock block is inserted into the lock slot, the movement of the push button is restricted, so that the push button cannot slide relative to the knife holder; when the lock block is separated from the lock slot and enters the channel, the push button can slide relative to the knife holder to release the lock; both ends of the baffle are vertically fixed with blocks corresponding to the lock block, which is convenient for limiting the sliding range of the push button relative to the knife holder and preventing the push button from detaching from the knife holder.

[0012] Preferably, the spring piece is an isosceles trapezoid structure formed by bending. The two ends of the spring piece are located at the top of the isosceles trapezoid structure after bending, and an opening gap is formed between the two ends. The two ends of the spring piece are arc-shaped structures. Installation areas matching the spring piece are formed between the retaining strip and the retaining block and the corresponding side walls of the groove respectively. A notch matching the top of the isosceles trapezoid structure formed by the spring piece is provided on the side wall of the groove. Both ends of the spring piece penetrate through the notch and are located outside the groove. A plurality of limiting grooves matching the two ends of the spring piece are provided on the side wall of the open end of the tool groove, and the plurality of limiting grooves are evenly distributed along the length direction of the tool groove. The driving part is a butting groove opened on the push button and in contact with the side walls of the two ends of the spring piece, and both ends of the spring piece are located in the butting groove. The opening gap provides space for the spring piece to deform; when the locking block is separated from the locking groove and enters the channel, the push button slides relative to the tool holder. The push button drives the spring piece to deform through the side wall of the butting groove to release the limit on the tool holder. The end of the spring piece is extruded from the current limiting groove to release the limiting effect of the spring piece on the tool holder. The tool holder can slide in the tool groove under the drive of the push button to adjust the length of the blade extending out of the housing.

[0013] Preferably, a support plate extends from the bottom side wall of the tool holder towards the cutting edge direction. The support plate is located in the tool groove. One end of the support plate is fixedly connected to the tool holder, and a limiting post is fixed at the other end of the support plate. A limiting hole matching the limiting post is provided on the blade. A limiting plate is fixed on the side wall of the convex block. The limiting plate and the support plate are distributed vertically and a slot matching the blade is formed between them. Such a design is beneficial to the quick disassembly, assembly and limitation of the blade.

[0014] The beneficial effects of the present utility model are as follows: it can play a role in positioning and locking both during the use of the blade or when the blade is stored in the tool groove, improving the user experience and achieving the purpose of facilitating the improvement of safety performance; the operation is convenient and fast; the cutting accuracy and use safety during the use of the blade are improved; it is convenient to toggle the locking switch back and forth. At the same time, it is beneficial to prevent slipping when the locking switch is toggled, facilitating the operation; both ends of the retaining strip are vertically fixed with retaining blocks corresponding to the locking block, which is convenient to limit the sliding range of the push button relative to the tool holder and prevent the push button from detaching from the tool holder; it is beneficial to the quick disassembly, assembly and limitation of the blade. Description of the Drawings

[0015] Figure 1 is the structural schematic diagram of the present utility model;

[0016] Figure 2 is the exploded view of the present utility model;

[0017] Figure 3 is the structural schematic diagram of the push button;

[0018] Figure 4It is a schematic structural diagram of the present utility model after removing the push button;

[0019] Figure 5 is Figure 4 an enlarged structural view of part A in

[0020] Figure 6 a schematic structural diagram of the locking switch.

[0021] In the figure: 1. housing, 2. blade, 3. knife groove, 4. knife seat, 5. spring piece, 6. push button, 7. locking switch, 8. locking groove, 9. cutting opening, 10. guiding inclined surface, 11. installation groove, 12. anti-slip pattern, 13. limiting convex shaft, 14. locking block, 15. rectangular hole, 16. limiting convex rib, 17. limiting area, 18. convex block, 19. groove, 20. blocking strip, 21. U-shaped block, 22. channel, 23. blocking block, 24. opening gap, 25. installation area, 26. notch, 27. limiting groove, 28. support plate, 29. limiting column, 30. limiting hole, 31. limiting plate, 32. slot, 33. driving part. Specific embodiments

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying 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. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0023] It should be noted that the terms used here are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used here, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0024] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components set forth in these embodiments do not limit the scope of the present application. For ease of description, spatial relative terms such as "upper", "lower", "left", "right", etc. are used in the embodiments to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that, in addition to the orientations shown in the figures, the spatial terms are intended to include different orientations of the device during use or operation. For example, if the device in the figure is inverted, the element described as being "below" other elements or features will be positioned "above" the other elements or features. Thus, the exemplary term "below" can encompass both upper and lower orientations. The device can be fixed in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein can be interpreted accordingly. At the same time, it should be understood that, for the sake of convenience in description, the sizes of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, processes, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, processes, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0025] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is merely for the convenience of distinguishing the corresponding components. Without otherwise stating, the above terms have no special meanings, and thus, should not be construed as limiting the protection scope of the present application.

[0026] Such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5In the described embodiment, a central locking utility knife includes a housing 1 and a blade 2. A knife groove 3 for accommodating the blade 2 is provided on the housing 1. The cross-sectional shape of the knife groove 3 is C-shaped. One end of the knife groove 3 is provided with a knife seat 4 detachably connected to the blade 2. The bottom of the knife seat 4 is located within the knife groove 3 and is slidably connected to the knife groove 3. A spring piece 5 and a push button 6 are respectively provided on the top of the knife seat 4. The spring piece 5 is located between the push button 6 and the knife seat 4 and is detachably and fixedly connected to the knife seat 4. The knife seat 4 is limited within the knife groove 3 by the spring piece 5. The push button 6 is located outside the knife groove 3. The push button 6 is slidably connected to the knife seat 4 and is provided with a driving portion 33 for driving the spring piece 5 to deform. A locking switch 7 is slidably connected to the push button 6. A locking groove 8 matching the locking switch 7 is provided on the knife seat 4. After the locking switch 7 slides relative to the push button 6, it cooperates with or separates from the locking groove 8. The other end of the knife groove 3 is provided with a cutting opening 9 matching the blade 2.

[0027] As Figure 1 and Figure 2 shown, a guiding inclined surface 10 is provided at the bottom of the other end of the knife groove 3. The shape of the guiding inclined surface 10 is an arc arching from the bottom of the knife groove 3 towards the inside of the knife groove 3. The bottom of the knife groove 3 is uniformly transitioned to the cutting opening 9 through the guiding inclined surface 10. The depth of the knife groove 3 is greater than the width in the same depth direction as the cutting opening 9 at the cutting opening 9.

[0028] As Figure 2 、 Figure 3 and Figure 6 shown, an installation groove 11 matching the locking switch 7 is provided on the top of the push button 6. The locking switch 7 is slidably connected to the installation groove 11 and its sliding direction is perpendicular to the sliding direction of the knife seat 4 along the knife groove 3. The top of the locking switch 7 gradually bulges outwards from its two ends towards its center. Anti-slip lines 12 are provided at both ends of the top of the locking switch 7. A limiting convex shaft 13 and a locking block 14 matching the locking groove 8 are respectively fixed to the bottom of the locking switch 7. A rectangular hole 15 is provided at the bottom of the installation groove 11. The limiting convex shaft 13 and the locking block 14 are both located within the rectangular hole 15. Limiting convex ribs 16 are provided on the side wall of the rectangular hole 15. Arc-shaped surfaces are provided on both the left and right sides of the limiting convex ribs 16. The limiting convex ribs 16 are connected to the side wall of the rectangular hole 15 through the arc-shaped surfaces to jointly form a wavy structure. Limiting areas 17 matching the limiting convex shaft 13 are formed on both the left and right sides of the limiting convex ribs 16.

[0029] As Figure 5As shown, a protrusion 18 is provided on the top of the knife seat 4, and the protrusion 18 is located in the open end of the knife groove 3. The bottom of the protrusion 18 is fixedly connected to the knife seat 4. The top of the protrusion 18 is located outside the knife groove 3 and is provided with a groove 19. The spring sheet 5 is detachably installed in the groove 19. The push button 6 covers the open end of the groove 19. The push button 6 is slidably connected to the open end of the groove 19 and its sliding direction is parallel to the sliding direction of the knife seat 4 along the knife groove 3. A baffle 20 and a U-shaped block 21 are respectively fixed in the groove 19. The baffle 20 is parallel to the length direction of the knife groove 3. The locking groove 8 is formed in the U-shaped block 21. The open end of the locking groove 8 is close to the baffle 20 and a channel 22 is formed between the baffle 20 for facilitating the passage of the locking block 14. The bottom of the locking groove 8 is away from the baffle 20. Both ends of the baffle 20 are vertically fixed with baffles 23 corresponding to the locking block 14.

[0030] like Figure 5 As shown, the spring sheet 5 is an isosceles trapezoidal structure formed by bending. The two ends of the spring sheet 5 are located at the top of the isosceles trapezoidal structure after bending and an open gap 24 is formed between the two ends. The two ends of the spring sheet 5 are arc-shaped structures. The retaining bar 20 and the retaining block 23 respectively form a mounting area 25 matching the spring sheet 5 between the corresponding side walls of the groove 19. The side wall of the groove 19 is provided with a notch 26 matching the top of the isosceles trapezoidal structure formed by the spring sheet 5. Both ends of the spring sheet 5 are located outside the groove 19 after passing through the notch 26. A number of limiting grooves 27 matching the two ends of the spring sheet 5 are provided on the side wall of the open end of the knife groove 3. The number of limiting grooves 27 are evenly distributed along the length direction of the knife groove 3. The driving part 33 is an abutting groove opened on the push button 6 and in contact with the two end side walls of the spring sheet 5. Both ends of the spring sheet 5 are located in the abutting groove.

[0031] like Figure 2 As shown, a support plate 28 is extended from the bottom side wall of the tool holder 4 toward the direction of the tool outlet 9, and the support plate 28 is located in the tool groove 3. One end of the support plate 28 is fixedly connected to the tool holder 4, and a limiting column 29 is fixed to the other end of the support plate 28. A limiting hole 30 matching the limiting column 29 is provided on the blade 2, and a limiting plate 31 is fixed on the side wall of the protrusion 18. The limiting plate 31 and the support plate 28 are distributed up and down, and a slot 32 matching the blade 2 is formed between the two.

[0032] The top of the locking switch 7 gradually bulges outward from its two ends toward its center, which is convenient for the locking switch 7 to be moved back and forth. At the same time, both ends of the top of the locking switch 7 are provided with anti-slip grooves 12, which are beneficial to prevent the locking switch 7 from slipping when being moved, and are convenient for operation.

[0033] The locking switch 7 is slidably connected to the mounting groove 11 to drive the locking block 14 thereon to cooperate with the locking groove 8 for locking or to separate from the locking groove 8 for unlocking; during the sliding process of the locking switch 7, the limiting convex shaft 13 smoothly slides into the limiting areas 17 on the left and right sides of the limiting convex rib 16 through the wavy structure jointly formed by the limiting convex rib 16 and the side wall of the rectangular hole 15, and respectively limits the locking switch 7 in the locked or unlocked state by the cooperation of the limiting convex shaft 13 and the limiting area 17.

[0034] When the operator toggles the locking switch 7 to insert the locking block 14 into the locking groove 8 for locking, the push button 6 cannot slide relative to the tool holder 4, and thus the push button 6 cannot drive the spring piece 5 to deform through the driving portion 33 to release the limit on the tool holder 4. Finally, the tool holder 4 cannot drive the blade 2 to slide in the tool groove 3, so that the blade 2 can be positioned and locked both during use or when the blade 2 is received in the tool groove 3, improving the user experience and achieving the purpose of facilitating the improvement of safety performance.

[0035] Conversely, when the operator slides the locking switch 7 to separate the locking block 14 from the locking groove 8 on the tool holder 4 and into the channel 22, the push button 6 can slide relative to the tool holder 4, and the locking can be released. During the sliding process of the push button 6, the side wall of the abutting groove drives the spring piece 5 to deform, and the end of the spring piece 5 is extruded from the current limiting groove 27 to release the limiting effect of the spring piece 5 on the tool holder 4. The tool holder 4 can slide in the tool groove 3 driven by the push button 6 to adjust the length of the blade 2 extending out of the housing; both ends of the blocking strip 20 are vertically fixed with blocking blocks 23 corresponding to the locking block 14, which is convenient for limiting the sliding range of the push button 6 relative to the tool holder 4 and preventing the push button 6 from detaching from the tool holder 4.

[0036] During use, when the operator pushes the blade 2 out of the tool groove 3 through the blade outlet 9, the width setting of the blade outlet 9 limits the upper and lower surfaces of the blade 2, preventing the blade 2 from shaking during use and improving the cutting accuracy and use safety of the blade 2.

Claims

1. A center-lock utility knife, characterized in that, It includes a housing (1) and a blade (2). A knife groove (3) for accommodating the blade (2) is provided on the housing (1). The cross-sectional shape of the knife groove (3) is C-shaped. A knife seat (4) detachably connected to the blade (2) is provided at one end of the knife groove (3). The bottom of the knife seat (4) is located in the knife groove (3) and is slidably connected to the knife groove (3). A spring piece (5) and a push button (6) are respectively provided at the top of the knife seat (4). The spring piece (5) is located between the push button (6) and the knife seat (4) and is detachably and fixedly connected to the knife seat (4). The knife seat (4) is limited in the knife groove (3) by the spring piece (5). The push button (6) is located outside the knife groove (3). The push button (6) is slidably connected to the knife seat (4) and is provided with a driving part (33) for driving the spring piece (5) to deform. A locking switch (7) is slidably connected to the push button (6). A locking groove (8) matching the locking switch (7) is provided on the knife seat (4). After the locking switch (7) slides relative to the push button (6), it cooperates with or separates from the locking groove (8). An outlet (9) matching the blade (2) is provided at the other end of the knife groove (3).

2. The center-lock utility knife according to claim 1, characterized in that, A guiding inclined surface (10) is provided at the bottom of the other end of the knife groove (3). The shape of the guiding inclined surface (10) is an arc arching from the bottom of the knife groove (3) towards the inside of the knife groove (3). The bottom of the knife groove (3) is uniformly transitioned to the outlet (9) through the guiding inclined surface (10). The depth of the knife groove (3) is greater than the width in the depth direction of the outlet (9) at the outlet (9).

3. The center-lock utility knife according to claim 1, characterized in that, An installation groove (11) matching the locking switch (7) is provided at the top of the push button (6). The locking switch (7) is slidably connected to the installation groove (11), and its sliding direction is perpendicular to the sliding direction of the knife seat (4) along the knife groove (3). The top of the locking switch (7) gradually bulges outwards from its two ends towards its center. Anti-slip patterns (12) are provided at both ends of the top of the locking switch (7). A limiting convex shaft (13) and a locking block (14) matching the locking groove (8) are respectively fixed at the bottom of the locking switch (7). A rectangular hole (15) is provided at the bottom of the installation groove (11). The limiting convex shaft (13) and the locking block (14) are both located in the rectangular hole (15). Limiting convex ribs (16) are provided on the side wall of the rectangular hole (15). Arc-shaped surfaces are provided on both the left and right sides of the limiting convex ribs (16). The limiting convex ribs (16) are connected to the side wall of the rectangular hole (15) through the arc-shaped surfaces to jointly form a wavy structure. Limiting areas (17) matching the limiting convex shaft (13) are formed on both the left and right sides of the limiting convex ribs (16).

4. The center-lock utility knife according to claim 3, characterized in that, A bump (18) is provided at the top of the tool holder (4). The bump (18) is located inside the opening end of the tool groove (3). The bottom of the bump (18) is fixedly connected to the tool holder (4). The top of the bump (18) is located outside the tool groove (3) and is provided with a groove (19). The spring piece (5) is detachably installed in the groove (19). The push button (6) covers the opening end of the groove (19). The push button (6) is slidably connected to the opening end of the groove (19), and its sliding direction is parallel to the sliding direction of the tool holder (4) along the tool groove (3). A stop bar (20) and a U-shaped block (21) are respectively fixed in the groove (19). The stop bar (20) is parallel to the length direction of the tool groove (3). The locking groove (8) is formed in the U-shaped block (21). The opening end of the locking groove (8) is close to the stop bar (20) and forms a passage (22) for the locking block (14) to pass through between the stop bar (20). The bottom of the locking groove (8) is far from the stop bar (20). Both ends of the stop bar (20) are perpendicularly fixed with stop blocks (23) corresponding to the locking block (14).

5. The center-lock utility knife according to claim 4, characterized in that, The spring piece (5) is an isosceles trapezoid structure formed by bending. The two ends of the spring piece (5) are bent and located at the top of the isosceles trapezoid structure, and an opening gap (24) is formed between the two ends. The two ends of the spring piece (5) are arc-shaped structures. The stop bar (20) and the stop blocks (23) respectively form an installation area (25) matching the spring piece (5) with the corresponding side walls of the groove (19). A notch (26) matching the top of the isosceles trapezoid structure formed by the spring piece (5) is provided on the side wall of the groove (19). Both ends of the spring piece (5) penetrate through the notch (26) and are located outside the groove (19). A plurality of limiting grooves (27) matching the two ends of the spring piece (5) are provided on the side wall of the opening end of the tool groove (3). The plurality of limiting grooves (27) are evenly distributed along the length direction of the tool groove (3). The driving part (33) is an abutting groove opened on the push button (6) and in contact with the side walls of the two ends of the spring piece (5). Both ends of the spring piece (5) are located in the abutting groove.

6. The center-lock utility knife according to claim 4, characterized in that, A support plate (28) extends from the bottom side wall of the tool holder (4) towards the cutting outlet (9). The support plate (28) is located inside the tool groove (3). One end of the support plate (28) is fixedly connected to the tool holder (4). A limiting post (29) is fixed at the other end of the support plate (28). A limiting hole (30) matching the limiting post (29) is provided on the blade (2). A limiting plate (31) is fixed on the side wall of the bump (18). The limiting plate (31) and the support plate (28) are distributed vertically, and a slot (32) matching the blade (2) is formed between them.

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