CN109434879B

CN109434879B - Practical knife with locking structure

Info

Publication number: CN109434879B
Application number: CN201811422566.8A
Authority: CN
Inventors: 周晓刚
Original assignee: Ningbo Hongdi Measuring Tape Industry Co ltd
Current assignee: Ningbo Hongdi Measuring Tape Industry Co ltd
Priority date: 2018-11-27
Filing date: 2018-11-27
Publication date: 2020-06-09
Anticipated expiration: 2038-11-27
Also published as: CN109434879A

Abstract

The invention discloses a practical knife with a locking structure, which comprises a shell (1), a knife rest (2), a blade (3), a push button (4) and a knife rest locking device (5); the front end of the shell (1) is provided with a blade telescopic opening (11) for the blade (3) to stretch, and the side surface of the shell (1) is provided with a sliding groove for the push button (4) to move; the blade (3) is arranged in the shell (1) in a matching way through the tool rest (2), and the blade (3) is controlled to stretch and retract at the blade telescopic opening (11) by pushing the button (4); the tool rest locking device (5) realizes telescopic locking of the blade (3) by locking the tool rest (2). The invention adopts the knife rest locking device to lock the knife rest, thereby limiting the telescopic motion of the blade, further realizing the locking of the blade and ensuring that the cutting work is not influenced by the automatic extension and retraction of the blade when the product is used.

Description

Practical knife with locking structure

Technical Field

The invention belongs to the technical field of art designing cutters, and particularly relates to a practical cutter with a locking structure.

Background

The art designing knife is also commonly called as a graver or a wallpaper knife, is a knife for art and handicraft, is mainly used for cutting objects with soft texture, mainly consists of a plastic knife handle and a blade, and is of a drawing structure. Also have a small number for the metal handle of a knife, the blade is mostly the bevel connection, can follow the marking off rupture of blade with the blunt, appears new blade point, facilitates the use. The utility knife is a utility knife, the push button is arranged at the top, the thumb can be used for pushing the push button and simultaneously pressing downwards when the knife edge cuts downwards, the blade is controlled by the push button, and meanwhile, the utility knife is a very practical utility knife. However, since the utility knife generally adopts a manual control push button to limit the blade, the blade cannot be stably controlled during use, and the cutting effect is further influenced; in addition, the assembly structure of the blade causes that the blade has a certain assembly gap, and the blade has a certain gap to shake in use, so that the common utility knife is not suitable for fine cutting.

Disclosure of Invention

Technical problem to be solved

The invention aims to solve the technical problem of providing a practical knife with lockable blade extension and gap.

(II) technical scheme

In order to solve the technical problem, the invention provides a practical knife with a locking structure, which comprises a shell, a knife rest, a blade, a push button and a knife rest locking device, wherein the knife rest is arranged on the shell; the front end of the shell is provided with a blade telescopic opening for the blade to stretch, and the side surface of the shell is provided with a chute for pushing the button to move; the blade is arranged in the shell in a matching way through the blade holder, and the blade is controlled to stretch and retract at the stretching port of the blade by pushing the button; the tool rest locking device realizes the telescopic locking of the blade by locking the tool rest.

The shell comprises a left shell and a right shell which are spliced and fixed left and right; a tool rest sliding groove which penetrates through the blade telescopic opening and is matched with the tool rest is formed in the inner wall of the right shell; the top surface of the shell is provided with a button sliding groove which penetrates through the tool rest sliding groove and is matched with the push button; the blade is fixedly clamped on the knife rest, and the knife rest carries the blade to be matched and arranged on the knife rest sliding groove; the push button is connected to the tool rest in a matching linkage manner and is exposed out of the shell from the button sliding groove;

the tool rest locking device comprises a gear locking push button matched with the button sliding groove and a linkage locking frame matched with the tool rest sliding groove, and a limiting convex block is arranged on the side edge of the gear locking push button; an unlocking tooth groove and a locking tooth groove which are matched with the limiting lug are formed in the shell between the button sliding groove and the tool rest sliding groove, the unlocking tooth groove is distributed at the rear end of the button sliding groove, the locking tooth groove is distributed in front of the unlocking tooth groove, and the height of the locking tooth groove is lower than that of the unlocking tooth groove; a spring hole is arranged in the middle of the bottom end of the gear locking push button, and a pressure spring matched with the spring hole is arranged in the spring hole; an extension plate which is higher than the tool rest extends out of the front end of the linkage locking frame, a through hole which is matched with the bottom end of the gear locking push button is formed in the extension plate, and a pressure spring stress plate which is matched with a spring hole is arranged in the middle of the through hole; the top end of the knife rest is provided with a limiting sleeve hole matched with the bottom end of the gear locking push button;

the linkage locking frame is arranged on the tool rest sliding groove in a matched mode and located behind the tool rest, the gear locking push button is clamped in the unlocking tooth groove through a limiting lug, the bottom end of the gear locking push button is sleeved in the through hole in a matched mode and does not penetrate out of the through hole under the action force of the pressure spring, and the top end of the gear locking push button is exposed out of the shell from the button sliding groove and located behind the push button; when the push button is close to the gear locking push button, the limiting sleeve joint hole of the tool rest is positioned right below the gear locking push button.

Wherein, the rear end of knife rest is provided with the spacing joint groove of the front end matching joint with linkage locking frame.

Wherein, a stressed tension spring is arranged between the linkage locking frame and the tool rest.

The utility knife with the locking structure further comprises a locking device, the locking device comprises a locking rod and an adjusting device, and the locking device adjusts the locking rod through the adjusting device to lock the blade.

Wherein, the inner wall of the left shell is provided with an inclined lug near the telescopic opening of the blade; the locking bar is arranged between the inner wall of the left shell and the blade, and the adjusting device is arranged at the rear end of the shell; the locking rod realizes the telescopic movement towards the direction of the blade telescopic opening through the control of the adjusting device, and the front end of the locking rod reduces the clearance between the locking rod and the blade through the inclined convex block and clamps and locks the blade.

The adjusting device comprises a locking screw and a locking knob, wherein the locking knob is provided with a threaded hole which is coaxial with the locking knob and is matched with the locking screw; the bottom end of the shell is provided with a knob sleeve hole matched with the locking knob; the locking knob is matched and sleeved in the knob sleeving hole; the front end of the locking screw is matched and fixedly connected with the rear end of the locking rod, and the rear end of the locking screw is matched and in threaded connection with the threaded hole of the locking knob; the locking rod realizes the telescopic motion towards the direction of the blade telescopic opening through the threaded connection adjustment between the locking knob and the locking screw rod.

Wherein, the blade is provided with a clamping fixing hole, and the tool rest is provided with a buckle matched and clamped with the clamping fixing hole; the blade realizes the fixed connection with the knife rest through the joint between buckle and the joint fixed orifices.

The tool changing device comprises a left shell, a left button, a left buckle, a left button, a right button, a left button and a right button, wherein the inner side wall of the left shell is also provided with the tool changing button, one end of the tool changing button is matched and clamped with the left shell, the other end of the tool changing button penetrates through the left shell and; the blade is replaced by pressing the tool changing button to push the top buckle to be separated from the clamping fixing hole.

(III) advantageous effects

Compared with the prior art, the invention utilizes the knife rest locking device to lock the knife rest, thereby limiting the telescopic motion of the blade, further realizing the locking of the blade and ensuring that the cutting work is not influenced by the automatic telescopic motion of the blade when the product is used; the extension spring is arranged between the linkage locking frame and the knife rest, so that the knife rest can conveniently carry the blade to contract and reset, and meanwhile, the blade is prevented from extending out of the blade telescopic opening when not in use, the situations such as accidental injury are effectively prevented, the safety performance is improved, and the carrying of the utility knife is convenient; in addition, the locking device that sets up adopts the structure of locking lever to press from both sides tight blade to reach the function of blade locking, make people can not have the clearance in the use and rock, save the operation that people's manual application of pressure restricted blade, effectively avoid the blade to slide and lead to cutting mistake or accidental injury people's the condition to appear, improve the accuracy of tailorring of this product.

Drawings

Fig. 1 is a schematic view of a utility knife with a locking structure according to the present invention.

Fig. 2 is a schematic structural view of the right housing of the utility knife with the locking structure of the invention.

Fig. 3 is a schematic structural view of the left housing of the present invention.

Fig. 4 is a schematic view of the utility knife with a locking structure shown in the left housing.

Description of reference numerals: 1. a housing; 2. a tool holder; 3. a blade; 4. pushing the button; 5. a tool holder locking device; 6. a tension spring; 7. a locking device; 11. a blade expansion port; 12. a left housing; 13. a right housing; 14. a button chute; 15. unlocking the tooth grooves; 16. locking the tooth grooves; 17. the knob is sleeved with the hole; 21. limiting the sleeving hole; 22. a limiting clamping groove; 23. buckling; 31. clamping the fixing holes; 51. a gear locking push button; 52. a linkage locking frame; 71. a locking bar; 72. an adjustment device; 121. a tilt projection; 122. a tool changing button; 123. a guide projection; 131. a tool holder sliding groove; 511. a restraining bump; 512. a spring hole; 513. a pressure spring; 521. an extension plate; 522. a through hole; 523. a pressure spring stress plate; 711. a guide groove; 721. locking the screw rod; 722. a locking knob; 7221. a threaded bore.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Fig. 1 is a schematic structural view of a utility knife with a locking structure according to the present invention, and the utility knife embodying the locking structure is composed of a housing 1, a knife holder 2, a blade 3, a push button 4 and a knife holder locking device 5, and a connection relationship therebetween; FIG. 2 is a schematic structural view of the right housing of the utility knife with the locking structure of the present invention, which mainly reflects the structural components of the knife rest locking device 5 and the locking device 7; fig. 3 is a schematic structural diagram of the left housing of the present invention, which shows the structures of the inclined protrusion 121, the tool changing button 122, the guiding protrusion 123, the unlocking tooth slot 15, the locking tooth slot 16, etc. on the left housing 12; fig. 4 is a schematic structural view of the left housing of the utility knife with the locking structure of the present invention, and mainly reflects the structures of the knife rest sliding groove 131 and the guide groove 711, etc.

The structure of the utility knife with the locking structure is shown in figure 1, and the utility knife with the locking structure comprises a shell 1, a knife rest 2, a blade 3, a push button 4 and a knife rest locking device 5; the front end of the shell 1 is provided with a blade telescopic opening 11 for the blade 3 to stretch, and the side surface of the shell 1 is provided with a sliding chute for pushing the button 4 to move; the blade 3 is arranged in the shell 1 in a matching way through the blade holder 2, and the blade 3 is controlled to perform telescopic movement at the blade telescopic opening 11 by pushing the button 4; the tool holder locking device 5 locks the tool holder 2 to telescopically lock the blade 3. The invention utilizes the knife rest locking device to lock the knife rest, thereby limiting the telescopic motion of the blade, further realizing the locking of the blade and ensuring that the cutting work is not influenced by the automatic extension and retraction of the blade when the product is used.

As shown in fig. 1, fig. 2, fig. 3 and fig. 4, in the present embodiment, the housing 1 includes a left housing 12 and a right housing 13 that are fixed to each other in a left-right manner; a tool rest sliding groove 131 which penetrates through the blade telescopic opening 11 and is matched with the tool rest 2 is formed in the inner wall of the right shell 13; the top surface of the shell 1 is provided with a button sliding chute 14 which penetrates through the tool rest sliding chute 131 and is matched with the push button 4; the blade 3 is fixedly clamped on the knife rest 2, and the knife rest 2 carries the blade 3 and is arranged on the knife rest sliding groove 131 in a matching way; the push button 4 is connected to the tool rest 2 in a matching linkage manner and is exposed out of the shell 1 from the button chute 14; wherein, an integral connecting structure is arranged between the push button 4 and the knife rest 2, and the knife rest 2 is controlled by pushing the push button 4;

the tool holder locking device 5 comprises a gear locking push button 51 matched with the button sliding groove 14 and a linkage locking frame 52 matched with the tool holder sliding groove 131, and a limiting convex block 511 is arranged on the side edge of the gear locking push button 51; an unlocking tooth groove 15 and a locking tooth groove 16 which are matched with the limiting lug 511 are arranged on the shell 1 between the button sliding groove 14 and the tool rest sliding groove 131, the unlocking tooth groove 15 is distributed at the rear end of the button sliding groove 14, the locking tooth groove 16 is distributed in front of the unlocking tooth groove 15, and the height of the locking tooth groove 16 is lower than that of the unlocking tooth groove 15; a spring hole 512 is arranged in the middle of the bottom end of the gear locking push button 51, and a compression spring 513 matched with the spring hole 512 is arranged in the spring hole 512; an extension plate 521 which is higher than the tool rest 2 extends from the front end of the linkage locking frame 52, a through hole 522 matched with the bottom end of the gear locking push button 51 is formed in the extension plate 521, and a pressure spring stress plate 523 matched with the spring hole 512 is arranged in the middle of the through hole 522; the top end of the tool rest 2 is provided with a limiting sleeve joint hole 21 matched with the bottom end of the gear locking push button 51;

the linkage locking frame 52 is mounted on the tool holder sliding groove 131 in a matched manner and is positioned behind the tool holder 2, the gear locking push button 51 is clamped in the unlocking tooth groove 15 through the limiting convex block 511, the bottom end of the gear locking push button 51 is sleeved in the through hole 522 in a matched manner and does not penetrate out of the through hole 522 under the action force of the compression spring 513, and the top end of the gear locking push button 51 is exposed out of the shell 1 from the button sliding groove 14 and is positioned behind the push button 4; when the push button 4 is close to the gear locking push button 51, the limiting sleeve hole 21 of the tool holder 2 is positioned right below the gear locking push button 51;

when the push button 4 is close to the gear locking push button 51, the locking push button 51 is pressed down to overcome the compression spring 513, penetrate through the through hole 522 and be inserted into the limiting sleeve hole 21, meanwhile, the limiting lug 511 on the locking push button 51 is separated from the unlocking toothed slot 15, then the locking push button 51 is pushed to drive the linkage locking frame 52 and the tool rest 2 to be pushed forwards together, and the blade 3 is linked together with the tool rest 2; when the locking push button 51 moves to the locking tooth groove 16, the locking push button 51 is released, the locking push button 51 rebounds upwards under the reset spring force of the compression spring 513, meanwhile, the limiting convex block 511 on the locking push button 51 is clamped into the locking tooth groove 16, and as the height of the locking tooth groove 16 is lower than that of the unlocking tooth groove 15, part of the bottom end of the locking push button 51 is inserted into the limiting sleeve hole 21 of the tool rest 2, so that the function of locking the tool rest 2 is achieved, and the blade 3 moving along with the tool rest 2 is telescopically locked. In addition, there are three locking splines 16 from front to back, allowing three telescopic locking positions for blade 3.

As shown in fig. 2 and 4, in the present embodiment, the rear end of the tool holder 2 is provided with a limit clamping groove 22 which is matched and clamped with the front end of the linkage locking frame 52; when the locking push button 51 is close to the tool holder 2, the linkage locking frame 52 is inserted into the limiting clamping groove 22 of the tool holder 2, so that the situation of movement and dislocation between the linkage locking frame 52 and the tool holder 2 is effectively prevented.

As shown in fig. 2 and 4, in this embodiment, a stressed tension spring 6 is disposed between the linkage locking frame 52 and the knife rest 2, so as to facilitate the knife rest to carry the blade to contract and reset, and meanwhile, ensure that the blade does not extend out of the blade contraction port when not in use, effectively prevent accidental injuries and the like, improve safety performance, and facilitate carrying of the utility knife. Wherein, also can set up an extension spring between knife rest 2 and casing 1, the effect of this extension spring is the same with the function of extension spring 6 above-mentioned.

As shown in fig. 1, 2 and 4, in the present embodiment, the utility knife with a locking structure further includes a locking device 7, the locking device 7 includes a locking bar 71 and an adjusting device 72, and the locking device 7 adjusts the locking bar 71 through the adjusting device 72 to lock the blade 3. The locking device provided by the invention clamps the blade by adopting the structure of the locking rod, so that the function of locking the blade is achieved, the gap shaking cannot occur when people use the locking device, the operation that people limit the blade by manually applying pressure is omitted, the situation that the blade slides to cause cutting errors or accidentally injure people is effectively avoided, and the cutting accuracy of the product is improved.

As shown in fig. 1, fig. 2, fig. 3 and fig. 4, in the present embodiment, an inclined protrusion 121 is disposed on the inner wall of the left housing 12 near the blade expansion port 11; the locking bar 71 is arranged between the inner wall of the left shell 12 and the blade 3, and the adjusting device 72 is arranged at the rear end of the shell 1; the locking bar 71 is controlled by the adjusting device 72 to realize its telescopic movement toward the blade extension 11, and the front end of the locking bar 71 reduces the gap with the blade 3 and clamps the locking blade 3 by tilting the protrusion 121. Wherein the inclined protrusion 121 is located between the blade 3 and the locking bar 71.

As shown in fig. 1, fig. 2, fig. 3 and fig. 4, in the present embodiment, the adjusting device 72 includes a locking screw 721 and a locking knob 722, and the locking knob 722 is provided with a threaded hole 7221 coaxial with the locking screw 721; the bottom end of the shell 1 is provided with a knob sleeve hole 17 matched with the locking knob 722; the locking knob 722 is matched and sleeved in the knob sleeve hole 17; the front end of the locking screw 721 is matched and fixedly connected with the rear end of the locking rod 71, and the rear end of the locking screw 721 is matched and in threaded connection with the threaded hole 7221 of the locking knob 722; the locking bar 71 is adjusted by the screw connection between the locking knob 722 and the locking screw 721 to achieve its telescopic movement in the direction of the blade extension 11. The invention utilizes the thread structure to enable the locking screw 721 to drive the locking rod 71 to perform telescopic motion together under the adjustment of the locking knob 722, reduces the gap between the locking screw and the blade 3 and clamps and locks the blade 3 by inclining the lug 121, and limits the telescopic motion and the gap swing of the blade 3, thereby avoiding the need of force to limit the blade 3 in the use of the cutter, and leading people to be more relaxed and convenient in the use. Wherein, the locking rod 71 is provided with a guide groove 711 along the telescopic movement direction thereof, and the inner wall of the left shell 12 is provided with a guide projection 123 matched with the guide groove 711; the locking bar 71 is positioned to limit the extension and contraction direction of the locking bar 71 by the guide groove 711 matching with the guide protrusion 123.

As shown in fig. 2 and 4, in this embodiment, a clamping fixing hole 31 is formed in the blade 3, and a buckle 23 that is matched and clamped with the clamping fixing hole 31 is arranged on the tool holder 2; the blade 3 is fixedly connected with the tool rest 2 through clamping between the clamping buckles 23 and the clamping fixing holes 31. Wherein, the buckle 23 can adopt the form of joint to be connected with the tool holder 2 buckle for this buckle 23 has certain removal resilience for tool holder 2, makes things convenient for buckle between buckle 23 and the joint fixed orifices 31 and breaks away from.

As shown in fig. 1, fig. 2, fig. 3, and fig. 4, in this embodiment, a tool changing button 122 is further disposed on an inner side wall of the left housing 12, one end of the tool changing button 122 is in matched clamping connection with the left housing 12, the other end of the tool changing button 122 extends out from an outer side surface of the left housing 12 after penetrating through the left housing 12, and a back structure of one end of the tool changing button 122 extending out from the left housing 12 is matched with the buckle 23; replacement of the blade 3 is achieved by the tool exchange button 122 pressing the ejector catch 23 out of the snap-fit hole 31. When this product uses, only need to promote button 4 and promote the flexible maximum of blade 3 to press the part that tool changing button 122 stretches out from left casing 12 with the side, tool changing button 122 can push open the joint structure between blade 3 and the knife rest 2 and realize the tool changing process.

The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, it is possible to make several improvements and modifications without departing from the technical principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. The utility knife with the locking structure is characterized in that: the utility knife with the locking structure comprises a shell (1), a knife rest (2), a blade (3), a push button (4) and a knife rest locking device (5); the front end of the shell (1) is provided with a blade telescopic opening (11) for the blade (3) to stretch, and the side surface of the shell (1) is provided with a sliding groove for the push button (4) to move; the blade (3) is arranged in the shell (1) in a matching way through the tool rest (2), and the blade (3) is controlled to stretch and retract at the blade telescopic opening (11) by pushing the button (4); the tool rest locking device (5) realizes telescopic locking of the blade (3) by locking the tool rest (2);

the shell (1) comprises a left shell (12) and a right shell (13) which are spliced and fixed left and right; a tool rest sliding groove (131) which penetrates through the blade telescopic opening (11) and is matched with the tool rest (2) is formed in the inner wall of the right shell (13); the top surface of the shell (1) is provided with a button sliding groove (14) which penetrates through the tool rest sliding groove (131) and is matched with the push button (4); the blade (3) is fixedly clamped on the knife rest (2), and the knife rest (2) with the blade (3) is arranged on the knife rest sliding groove (131) in a matching way; the push button (4) is connected to the tool rest (2) in a matching linkage manner and is exposed out of the shell (1) from the button sliding groove (14);

the tool rest locking device (5) comprises a gear locking push button (51) matched with the button sliding groove (14) and a linkage locking frame (52) matched with the tool rest sliding groove (131), and a limiting convex block (511) is arranged on the side edge of the gear locking push button (51); an unlocking tooth groove (15) and a locking tooth groove (16) which are matched with the limiting bump (511) are formed in the shell (1) between the button sliding groove (14) and the tool rest sliding groove (131), the unlocking tooth groove (15) is distributed at the rear end of the button sliding groove (14), the locking tooth groove (16) is distributed in front of the unlocking tooth groove (15), and the height of the locking tooth groove (16) is lower than that of the unlocking tooth groove (15); a spring hole (512) is formed in the middle of the bottom end of the gear locking push button (51), and a compression spring (513) matched with the spring hole (512) is arranged in the spring hole (512); an extension plate (521) higher than the tool rest (2) extends out of the front end of the linkage locking frame (52), a through hole (522) matched with the bottom end of the gear locking push button (51) is formed in the extension plate (521), and a pressure spring stress plate (523) matched with the spring hole (512) is arranged in the middle of the through hole (522); the top end of the tool rest (2) is provided with a limiting sleeve hole (21) matched with the bottom end of the gear locking push button (51);

the linkage locking frame (52) is installed on the tool rest sliding groove (131) in a matched mode and located behind the tool rest (2), the gear locking push button (51) is clamped in the unlocking tooth groove (15) through the limiting convex block (511), the bottom end of the gear locking push button (51) is sleeved in the through hole (522) in a matched mode and does not penetrate out of the through hole (522) under the action force of the pressure spring (513), and the top end of the gear locking push button (51) is exposed out of the shell (1) from the button sliding groove (14) and located behind the push button (4); when the push button (4) is close to the gear locking push button (51), the limiting sleeve hole (21) of the tool rest (2) is positioned right below the gear locking push button (51).

2. A utility knife with a locking structure as claimed in claim 1, wherein: the rear end of the knife rest (2) is provided with a limiting clamping groove (22) which is matched and clamped with the front end of the linkage locking frame (52).

3. A utility knife with a locking structure as claimed in claim 1, wherein: a stressed tension spring (6) is arranged between the linkage locking frame (52) and the tool rest (2).

4. A utility knife with a locking structure as claimed in claim 1, wherein: the utility knife with the locking structure further comprises a locking device (7), the locking device (7) comprises a locking rod (71) and an adjusting device (72), and the locking device (7) adjusts the locking rod (71) through the adjusting device (72) to lock the blade (3).

5. The utility knife with locking structure of claim 4, wherein: an inclined bump (121) is arranged on the inner wall of the left shell (12) close to the blade telescopic opening (11); the locking rod (71) is arranged between the inner wall of the left shell (12) and the blade (3), and the adjusting device (72) is arranged at the rear end of the shell (1); the locking rod (71) realizes the telescopic movement towards the direction of the blade telescopic opening (11) through the control of the adjusting device (72), and the front end of the locking rod (71) reduces the clearance between the locking rod and the blade (3) through the inclined lug (121) and clamps the locking blade (3).

6. The utility knife with locking structure of claim 5, wherein: the adjusting device (72) comprises a locking screw (721) and a locking knob (722), and a threaded hole (7221) which is coaxial with the locking knob (722) and matched with the locking screw (721) is formed in the locking knob (722); the bottom end of the shell (1) is provided with a knob sleeve hole (17) matched with the locking knob (722); the locking knob (722) is sleeved in the knob sleeve hole (17) in a matching way; the front end of the locking screw (721) is matched and fixedly connected with the rear end of the locking rod (71), and the rear end of the locking screw (721) is matched and in threaded connection with a threaded hole (7221) of a locking knob (722); the locking rod (71) realizes the telescopic movement towards the direction of the blade telescopic opening (11) through the threaded connection adjustment between the locking knob (722) and the locking screw (721).

7. A utility knife with a locking structure as claimed in claim 1, wherein: a clamping fixing hole (31) is formed in the blade (3), and a buckle (23) matched and clamped with the clamping fixing hole (31) is arranged on the tool rest (2); the blade (3) is fixedly connected with the tool rest (2) through clamping between the buckle (23) and the clamping fixing hole (31).

8. A utility knife with a latch structure according to claim 7, wherein: a tool changing button (122) is further arranged on the inner side wall of the left shell (12), one end of the tool changing button (122) is connected with the left shell (12) in a matched and clamped mode, the other end of the tool changing button (122) penetrates through the left shell (12) and then extends out of the outer side face of the left shell (12), and the back face structure of one end, extending out of the left shell (12), of the tool changing button (122) is matched with the buckle (23); the blade (3) is replaced by pressing the tool changing button (122) to push the ejecting buckle (23) to be separated from the clamping fixing hole (31).