CN220209361U - Connector with secondary lock - Google Patents

Abstract

The utility model discloses a connector with a secondary lock, which comprises a shell, a terminal and the secondary lock; the secondary lock is provided with a preassembly position and a locking position in the insertion cavity, the secondary lock avoids the terminal when being in the preassembly position, and the secondary lock locks the terminal inserted into the terminal hole when being in the locking position; two lateral protruding limit buckling platforms are arranged on the two side faces of the secondary lock at intervals up and down, a first buckling position is formed between the two limit buckling platforms, a second buckling position is formed on the upper side of the upper limit buckling platform, the protruding height of the upper limit buckling platform is larger than that of the lower limit buckling platform, a stop buckling platform and a yielding groove are arranged on the upper portion of the corresponding side wall of the insertion cavity, when the secondary lock is located at the preassembly position, the stop buckling platform is buckled to the first buckling position, and when the secondary lock is located at the locking position, the stop buckling platform is buckled to the second buckling position. The connector is reasonable in design, enhances convenience in assembly operation, increases product usability, and has good practicability and popularization.

Description

Connector with secondary lock

Technical Field

The present utility model relates to an electrical connector, and more particularly, to a connector with a secondary lock.

Background

The electric connector is widely applied to various electric circuits and plays a role of connecting the circuits. In order to ensure the reliability of electrical connection, the inner ends of the connectors are required to be firmly fixed, secondary locks are arranged on many existing connectors, and the secondary locks stop the terminals, so that the tensile strength of the terminals in place is improved, and the risk that the terminals are pulled by external force to fall off is greatly reduced.

In patent document CN105789976B, a connector is disclosed, comprising a cover comprising: a first cable insertion hole into which a cable terminal is to be inserted; a coupling space (corresponding to an insertion cavity in the present application) provided to be recessed and communicate with the first cable insertion hole; and a housing (corresponding to the housing in the present application) including a cantilever-like housing lock, one end of which is locked in one side of the coupling space and the other end of which is a free end; the connector includes a position assurance member (equivalent to a secondary lock in the present application) to be inserted into the coupling space and fastened to the shell lock; the housing lock may be configured to adjust an insertion length of the position assurance member; the position assurance member may comprise: a slider to be slidingly coupled to the coupling space; a second cable insertion hole configured to penetrate the sliding body; and an action part arranged at one side of the sliding body to interfere with the shell lock; the housing lock may include a locking protrusion provided in a shape having a front portion at an acute angle and a rear portion at an obtuse angle with respect to an insertion direction of the position assurance member. In the connector of the above patent document, the position holding member realizes primary locking (i.e., in the pre-installation position) and secondary locking (i.e., in the locking position) of the position holding member by the engagement of the cantilever-like housing lock with the separation projecting portion and the fixing projecting portion at different positions, the cantilever-like housing lock having good elasticity, and the cantilever-like housing lock, the separation projecting portion and the fixing projecting portion being designed to be more easily inserted and more difficult to be removed from the position holding member; the problem that the structure in the above patent document is easy to occur is that the force of pressing the secondary lock into the insertion cavity for the first time is not easy to grasp when the connector is assembled manually, and the secondary lock is easy to be pressed into the locking position, namely, the secondary lock is pressed into place completely when the force is large, so that the secondary lock is required to be retracted to the preassembled position when the terminal is assembled, and then the secondary lock is pressed into the locking position after the terminal is assembled, thereby causing difficult and complicated operation and being unfavorable for improving the production efficiency.

Disclosure of Invention

Aiming at the defects pointed out in the background art, the utility model aims to provide the connector with more reasonable structural design, and the connector can be obviously limited at the preassembly position when the secondary lock is installed, so that the problem that the secondary lock can be directly pressed in place when the force is large can be effectively avoided.

The technical scheme for realizing the aim of the utility model is as follows:

the utility model relates to a connector with a secondary lock, which comprises a shell, a terminal and the secondary lock; the secondary lock is inserted by a socket at the upper end of the inserting cavity and is provided with a preassembly position and a locking position in the inserting cavity, the secondary lock is prevented from being inserted into the terminal hole when being in the preassembly position, and the secondary lock is locked in the locking position for the terminal inserted into the terminal hole; the secondary lock is characterized in that two lateral protruding limit buckling platforms are arranged on the two side faces of the secondary lock at intervals up and down, a first buckling position is formed between the two limit buckling platforms, a second buckling position is formed on the upper side of the upper limit buckling platform, the protruding height of the upper limit buckling platform is larger than that of the lower limit buckling platform, a stop buckling platform and a yielding groove located below the stop buckling platform are arranged on the upper portion of the corresponding side wall of the insertion cavity, when the secondary lock is located at the preassembly position, the stop buckling platform is buckled to the first buckling position, and when the secondary lock is located at the locking position, the stop buckling platform is buckled to the second buckling position.

In a further technical scheme of the utility model, the shell comprises a front shell and a rear shell which are connected in a clamping way, and the insertion cavity is formed between the front shell and the rear shell.

In a further technical scheme of the utility model, two side baffles protruding forwards are arranged at two side parts of the rear shell, the stop buckling table and the yielding groove are arranged on the side baffles, a first clamping part is arranged on the side baffles, the front shell is positioned between the two side baffles, a second clamping part which is clamped with the first clamping part is arranged on the corresponding side surface of the front shell, and one of the first clamping part and the second clamping part is a clamping table, and the other is a clamping hole.

In a further technical scheme of the utility model, a positioning insertion platform arranged along the front-rear direction is arranged on the inner side surface of the side baffle, a positioning slot in plug-in fit with the positioning insertion platform is arranged on the side surface of the front shell, the first clamping part is arranged on the positioning insertion platform, and the second clamping part is arranged in the positioning slot.

In a further technical scheme of the utility model, the upper end of the secondary lock is provided with a prying opening, and the prying opening is exposed when the secondary lock is in a locking position.

In a further technical scheme of the utility model, the upper end of the secondary lock protrudes out of the socket when the secondary lock is in the preassembly position, and the upper end of the secondary lock is flush with or lower than the socket when the secondary lock is in the locking position.

In a further technical scheme of the utility model, a first foolproof plug-in structure is arranged between the terminal hole and the terminal, and a second foolproof plug-in structure is arranged between the plug-in cavity and the secondary lock.

In a further technical scheme of the utility model, an elastic lock catch which is matched and connected with the opposite-plug connector is arranged on the shell, the free end of the elastic lock catch is used as an unlocking pressing handle to extend backwards, a gap is arranged between the elastic lock catch and the shell, and a limiting plug buckle is inserted into the gap.

According to the further technical scheme, the limiting eye-splice is arranged in the gap when moving forwards and backwards, and is provided with a limiting position for limiting the elastic lock catch support and a tripping position for releasing the limiting of the elastic lock catch support, the elastic lock catch is prevented from deforming towards the inner direction of the gap when the limiting eye-splice is positioned at the limiting position, and the elastic lock catch can deform towards the inner direction of the gap when the limiting eye-splice is positioned at the tripping position.

According to a further technical scheme, blocking strips extending in the front-rear direction are arranged on the surface of the shell on the two sides of the elastic lock catch, an n-shaped stop block is connected between the rear ends of the two blocking strips and above the unlocking pressing handle, the gap is located between the two blocking strips, a limiting sliding groove extending in the front-rear direction is formed in the inner side of the blocking strip, and a limiting elastic buckle in sliding limiting fit with the limiting sliding groove and an elastic clamping hook suitable for being buckled with a buckling hole of the elastic lock buckle when the elastic lock buckle is located at the limiting position are arranged on the limiting inserting buckle.

The utility model has the positive effects that: the connector structure of the utility model is optimally designed, so that convenience of assembly operation is enhanced; when the secondary lock is assembled on the shell, in the process of inserting the secondary lock into the inserting cavity to the preassembly position, the stop buckling table firstly enters the first buckling position through the lower limit buckling table to realize the locking of the secondary lock at the preassembly position, and in the process of continuously downwards pressing the secondary lock to the locking position, the stop buckling table can slide out of the first buckling position and enter the second buckling position through the upper limit buckling table, so that the locking of the secondary lock at the locking position is realized, and as the protrusion height of the lower limit buckling table is lower than that of the upper limit buckling table, the stop buckling table receives larger resistance when the secondary lock is assembled and has obvious blocking when the secondary lock reaches the preassembly position, the problem that the terminal is not beneficial to being assembled due to complete pressing in place when the secondary lock is pressed downwards for the first time can be avoided; meanwhile, the stop buckling table can form effective limit at the second buckling position when the secondary lock is installed in place, and the fixing reliability of the secondary lock is ensured.

Drawings

These and/or other aspects, features and advantages of the present disclosure will become more apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic view of a connector according to the present utility model;

FIG. 2 is a cross-sectional view of the connector of the present utility model (secondary lock in a pre-load position);

FIG. 3 is a cross-sectional view of the connector of the present utility model (secondary lock in the locked position);

FIG. 4 is an enlarged view of FIG. 2 at A;

FIG. 5 is an enlarged view at B in FIG. 3;

FIG. 6 is a schematic view of the secondary lock of the present utility model;

FIG. 7 is an exploded view of the connector of the present utility model;

FIG. 8 is a schematic view of a terminal according to the present utility model;

FIG. 9 is a schematic view of a connector according to another embodiment of the present utility model;

FIG. 10 is a schematic view of the connector of FIG. 9 with the limit button removed;

FIG. 11 is a front view of a limit tab of the present utility model;

FIG. 12 is a front view of the connector of the present utility model;

FIG. 13 is a cross-sectional view taken along line C-C of FIG. 12;

fig. 14 is a sectional view taken along line D-D of fig. 12.

The reference numerals shown in the figures are: 1-a housing; 11-terminal holes; 111-a first fool-proof slot; 12-inserting a cavity; 120-socket; 121-a stop button table; 122-yielding slots; 123-a second fool-proof slot; 13-front shell; 130-positioning slots; 131-clamping table; 14-a rear shell; 141-side baffles; 142-clamping holes; 143-positioning the insertion platform; 15-elastic lock catches; 151-button holes; 152-unlocking the pressing handle; 16-limiting eye-splice; 161-limiting snap; 162-elastic hook; 17-gap; 171-limiting sliding grooves; 18-barrier strips; 19-n-shaped stop; a 2-terminal; 21-a first foolproof plug; 3-secondary lock; 30-prying the mouth; 31-limiting buckling table; 32-a first buckling position; 33-a second buckling position; 34-a second foolproof plug.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present utility model more clear, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model.

A connector in the present embodiment, as shown in fig. 1 to 8, includes a housing 1, a terminal 2, and a secondary lock 3; the shell 1 is provided with a terminal hole 11 for inserting the terminal 2, the middle part of the shell 1 corresponding to the terminal hole 11 is provided with an inserting cavity 12 vertically communicated with the terminal hole 11, the secondary lock 3 is inserted by a socket 120 at the upper end of the inserting cavity 12 and is provided with a preassembly position and a locking position in the inserting cavity 12, the secondary lock 3 avoids the terminal 2 when being in the preassembly position so that the terminal 2 can be inserted into the terminal hole 11, the secondary lock 3 locks the terminal 2 inserted into the terminal hole 11 when being in the locking position, and the lower end of the secondary lock 3 is propped against the inner bottom of the inserting cavity 12 when being in the locking position; when the connector in this embodiment is assembled, the secondary lock 3 is firstly inserted into the insertion cavity 12 from the insertion opening 120 to the preassembly position to avoid the terminal 2, then the terminal 2 is fully inserted into the terminal hole 11 from the rear end opening of the terminal hole 11, and then the secondary lock 3 is continuously pressed downwards to reach the locking position, so that the terminal 2 is stopped and locked, and the terminal 2 is prevented from being released.

More specifically, two laterally protruding limit buckling platforms 31 are arranged at upper and lower intervals on two sides of the secondary lock 3, a first buckling position 32 is formed between the two limit buckling platforms 31, a second buckling position 33 is formed on the upper side of the upper limit buckling platform 31, the protruding height of the upper limit buckling platform 31 is larger than the protruding height (L in the height difference of the two limit buckling platforms 31 in FIG. 4), a limit buckling platform 121 and a yielding groove 122 positioned below the limit buckling platform 121 are arranged on the upper portion of the corresponding side wall of the inserting cavity 12, the yielding groove 122 can yield the limit buckling platform 31, when the secondary lock 3 is positioned at the preassembly position, the limit buckling platform 121 is buckled at the first buckling position 32, when the secondary lock 3 is positioned at the locking position, the secondary lock 3 is buckled at the second buckling position, the limit buckling position 33 is designed to be in the process of inserting the secondary lock 3 to the preassembly position, the limit buckling platform 121 enters the first buckling position 32 through the lower limit buckling platform 31, and the secondary lock 3 is not in the process of being pushed down to the lower limit buckling position 31, thereby the problem that the secondary lock 3 can be completely stressed when the secondary lock 3 is positioned at the lower limit buckling position 31 is not stressed to be completely reached to the lower than the limit buckling position of the upper limit buckling platform 31 is realized, and the problem that the secondary lock 3 can be completely pressed down to the limit buckling position is not in the lower than the limit buckling position of the limit buckling platform 31 is completely when the lower than the limit buckling position is pressed to be at the lower than the limit buckling position 31; meanwhile, the stop buckling table can be effectively limited at the second buckling position when the secondary lock 3 is installed in place, and the fixing reliability of the secondary lock is ensured. In order to reduce the resistance when the secondary lock is inserted into the insertion cavity 12, the longitudinal cross-sectional shapes of the stop catch base 31 and the stop catch base 121 in this embodiment are preferably triangular, trapezoidal or circular arc.

As shown in fig. 7, in order to optimize the production process of the housing 1, the housing 1 in this embodiment includes a front housing 13 and a rear housing 14 that are connected by a snap connection, and the insert cavity 12 is formed between the front housing 13 and the rear housing 14, so that two sets of molds can be used to produce the front housing 13 and the rear housing 14, respectively, and then the front end of the terminal hole 11 is located on the front housing 13, and the rear end of the terminal hole 11 is located on the rear housing 14.

In this embodiment, two side portions of the rear shell 14 are provided with side baffles 141 protruding forward, the stop buckle table 121 and the yielding groove 122 are disposed on the side baffles 141, the side baffles 141 are provided with first clamping portions, the front shell 13 is located between the two side baffles 141, the corresponding side surface of the front shell 13 is provided with second clamping portions clamped with the first clamping portions, the first clamping portions are clamping holes 142, the second clamping portions are clamping tables, the side baffles 141 on two sides of the rear shell 14 can play a lateral limiting role on the front shell 13, and meanwhile, the clamping tables 131 are matched with the clamping holes 142 to enable the front shell 13 to be effectively assembled and connected with the rear shell 14; as a modification, the first clamping portion may be a clamping table, and the second clamping portion may be a clamping hole in actual operation.

Referring to fig. 7, in order to further increase the connection strength between the side baffle 141 and the front shell 13, in this embodiment, a positioning insertion platform 143 is disposed on the inner side surface of the side baffle 141 and is disposed along the front-rear direction, a positioning slot 130 is disposed on the side surface of the front shell 13 and is in insertion fit with the positioning insertion platform 143, the housing 1 is inserted into the positioning slot 130 through the positioning insertion platform 143 during assembly to perform positioning, the first clamping portion is disposed on the positioning insertion platform 143, and the second clamping portion is disposed in the positioning slot 130.

Referring to fig. 6, for convenience in disassembly of the secondary lock 3, a prying opening 30 is provided at an upper end of the secondary lock 3, and the prying opening 30 is exposed when the secondary lock 3 is in a locking position, so that when the secondary lock 3 needs to be disassembled, a screwdriver tip can be inserted into the prying opening 30 to pry the secondary lock 3 upward, thereby facilitating operation.

In order to prevent the reverse plugging of the connector and the opposite plug connector during plugging in the present embodiment, the upper end of the secondary lock 3 is designed to protrude from the socket 120 when the secondary lock 3 is in the pre-installed position, and the upper end of the secondary lock 3 is flush with the socket 120 or lower than the socket 120 when the secondary lock 3 is in the locked position, so that when the secondary lock 3 is still in the pre-installed position, the protruding portion at the upper end of the secondary lock 3 can interfere with the opposite plug connector, so that the two cannot be plugged in, and a fool-proof effect is achieved.

In this embodiment, a first foolproof plug structure is arranged between the terminal hole 11 and the terminal 2, and a second foolproof plug structure is arranged between the plug cavity 12 and the secondary lock 3, so that the terminal 2 can be prevented from being reversely inserted into the terminal hole 11 through the arrangement of the first foolproof plug structure, and meanwhile, the secondary lock 3 can be prevented from being reversely inserted into the plug cavity 12 through the arrangement of the second foolproof plug structure, so that the assembly quality is ensured, and the assembly efficiency is improved; the first foolproof plug structure and the second foolproof plug structure can adopt such structures: the first fool-proof plug-in structure comprises a first fool-proof slot 111 arranged in the terminal hole 11 and a first fool-proof plug-in block 21 arranged on the terminal 2, and the second fool-proof structure comprises a second fool-proof slot 123 arranged in the plug cavity 12 and a second fool-proof plug-in block 34 arranged on the secondary lock 3; during assembly, the terminal 2 can be inserted into the terminal hole 11 only under the condition that the first fool-proof inserting block 21 is aligned with the first fool-proof inserting groove 111, and the secondary lock can be inserted into the inserting cavity 12 only under the condition that the second fool-proof inserting block 34 is aligned with the second fool-proof inserting groove 123 by the same reason, so that misplug during assembly can be effectively avoided, and fool-proof effect is achieved.

In a further embodiment, referring to fig. 9 to 14, the housing 1 is provided with an elastic lock catch 15 which is cooperatively connected with the opposite-plug connector, the free end of the elastic lock catch 15 is used as an unlocking pressing handle 152 to extend backwards, a gap 17 is formed between the elastic lock catch 15 and the housing 1, the elastic lock catch 15 locks when the connector is in plug-in connection with the opposite-plug connector, and when the connection with the opposite-plug connector is released, the unlocking pressing handle 152 is pressed towards the direction of the housing 1 to deform the elastic lock catch 15 so as to separate from a buckling position on the opposite-plug connector to realize unbuckling; in order to prevent abnormal unlocking caused by mistakenly pressing the elastic lock catch 15, in this embodiment, the limiting eye-splice 16 is inserted into the gap 17, and the elastic lock catch 15 is supported by the limiting eye-splice 16, so that abnormal unlocking caused by deformation of the elastic lock catch 15 due to the pressing of an external force is prevented.

In this embodiment, the limit buckle 16 is disposed in the gap 17 when moving back and forth, and has a limit position for supporting and limiting the elastic buckle 15 and a release position for releasing the supporting and limiting the elastic buckle 15, the limit buckle 16 can be moved between the limit position and the release position by moving the limit buckle 16, when the limit buckle 16 is in the limit position, the elastic buckle 15 can be prevented from deforming in the gap, that is, when the limit buckle 16 is in the limit position, the elastic buckle 15 can not be pressed to deform, so that the locking connection between the connector and the opposite-plug connector can not be released, thereby avoiding the occurrence of abnormal unlocking condition, and when the limit buckle 16 is in the release position, the elastic buckle 15 can deform in the gap, that is, when the limit buckle 16 is in the release position, the connector and the opposite-plug connector can be released by pressing the buckle 15 to deform, thereby separating the connector and the opposite-plug connector.

Further, as shown in fig. 10 to 14, the two sides of the elastic lock 15 on the surface of the housing 1 are provided with a blocking strip 18 extending along the front-rear direction, the blocking strip 18 can shield and protect the elastic lock 15 from the side, an n-shaped stop 19 is connected between the rear ends of the two blocking strips 18 and above the unlocking pressing handle 152, the unlocking pressing handle 152 can be shielded and protected by the n-shaped stop 19, the unlocking is avoided being pressed by mistake, the gap 17 is located between the two blocking strips 18, a limit chute 171 extending along the front-rear direction is arranged on the inner side of the blocking strip 18, a limit elastic buckle 161 which forms a sliding limit fit with the limit chute 171 and a limit hook 162 which is suitable for being buckled with the limit chute 151 on the elastic lock 15 when being located at the limit position can prevent the limit buckle 16 from falling from the gap 17, meanwhile, the limit buckle 16 can be effectively limited on the limit position by matching the limit hook 162 with the limit chute 151 on the elastic lock 15, and the limit buckle 16 can be removed to the limit position when the limit buckle 16 is released from the limit position.

It is to be understood that the above examples of the present utility model are provided by way of illustration only and not by way of limitation of the embodiments of the present utility model. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While those obvious variations or modifications which come within the spirit of the utility model remain within the scope of the utility model.

Claims (10)

1. A connector with a secondary lock comprises a shell (1), a terminal (2) and a secondary lock (3);

the secondary lock (3) is inserted by a socket (120) at the upper end of the inserting cavity (12) and is provided with a preassembly position and a locking position in the inserting cavity (12), the secondary lock (3) is prevented from being inserted into the terminal (2) when being positioned at the preassembly position, so that the terminal (2) can be inserted into the terminal hole (11), and the secondary lock (3) is locked on the terminal (2) inserted into the terminal hole (11) when being positioned at the locking position;

the novel lock is characterized in that two lateral protruding limiting buckling platforms (31) are arranged on the two side faces of the secondary lock (3) at intervals up and down, a first buckling position (32) is formed between the two limiting buckling platforms (31), a second buckling position (33) is formed on the upper side of the upper limiting buckling platform (31), the protruding height of the upper limiting buckling platform (31) is larger than that of the lower limiting buckling platform (31), a stop buckling platform (121) and a yielding groove (122) located below the stop buckling platform (121) are arranged on the upper portion of the corresponding side wall of the inserting cavity (12), when the secondary lock (3) is located in a preassembly position, the stop buckling platform (121) is buckled to the first buckling position (32), and when the secondary lock (3) is located in a locking position, the stop buckling platform (121) is buckled to the second buckling position (33).

2. The connector with the secondary lock according to claim 1, wherein the housing (1) includes a front housing (13) and a rear housing (14) which are snap-connected, and the insertion cavity (12) is formed between the front housing (13) and the rear housing (14).

3. The connector with the secondary lock according to claim 2, wherein side baffles (141) protruding forward are provided at both sides of the rear housing (14), the stopper catch (121) and the giving-up groove (122) are provided on the side baffles (141), a first detent portion is provided on the side baffles (141), the front housing (13) is located between the side baffles (141) and a second detent portion engaged with the first detent portion is provided on a corresponding side of the front housing (13), one of the first detent portion and the second detent portion is a detent (131), and the other is a detent (142).

4. A connector with a secondary lock according to claim 3, wherein a positioning insertion stage (143) is provided on an inner side surface of the side shield (141) along a front-rear direction, a positioning slot (130) is provided on a side surface of the front housing (13) and is in plug-in fit with the positioning insertion stage (143), the first clamping portion is provided on the positioning insertion stage (143), and the second clamping portion is provided in the positioning slot (130).

5. The connector with the secondary lock according to claim 1, wherein a prying opening (30) is formed in the upper end of the secondary lock (3), and the prying opening (30) is exposed when the secondary lock (3) is in a locking position.

6. The connector with secondary lock according to claim 1, wherein the secondary lock (3) protrudes from the socket (120) at an upper end in a pre-assembled position, and wherein the secondary lock (3) is flush with the socket (120) or below the socket (120) in a locked position.

7. Connector with secondary lock according to claim 1, characterized in that a first foolproof plug structure is arranged between the terminal hole (11) and the terminal (2), and a second foolproof plug structure is arranged between the plug cavity (12) and the secondary lock (3).

8. The connector with the secondary lock according to claim 1, wherein the shell (1) is provided with an elastic lock catch (15) which is in fit connection with the opposite-plug connector, the free end of the elastic lock catch (15) is used as an unlocking pressing handle (152) to extend backwards, a gap (17) is arranged between the free end and the shell (1), and a limiting plug buckle (16) is inserted into the gap (17).

9. The connector with the secondary lock according to claim 8, wherein the limit buckle (16) is disposed in the gap (17) when being movable back and forth, and has a limit position for supporting and limiting the elastic lock buckle (15) and a release position for releasing the supporting and limiting the elastic lock buckle (15), the limit buckle (16) prevents the elastic lock buckle (15) from being deformed in the direction of the gap when being in the limit position, and the elastic lock buckle (15) is deformable in the direction of the gap when being in the release position.

10. The connector with the secondary lock according to claim 9, wherein barrier strips (18) extending in the front-rear direction are arranged on two sides of the elastic lock catch (15) on the surface of the shell (1), an n-shaped stop block (19) is connected between the rear ends of the two barrier strips (18) and above the unlocking pressing handle (152), a gap (17) is positioned between the two barrier strips (18), a limiting sliding groove (171) extending in the front-rear direction is arranged on the inner side of the barrier strips (18), and a limiting elastic buckle (161) forming a sliding limiting fit with the limiting sliding groove (171) and an elastic clamping hook (162) suitable for being buckled with a buckling hole (151) on the elastic lock catch (15) when being located at the limiting position are arranged on the limiting inserting buckle (16).