CN2809929Y - Latch structure of card edge connector - Google Patents

Abstract

A card edge connector latch structure and circuit board form a space for setting up the electronic assembly conveniently, including a metal supporting arm, it has a spanning arm and a pair of stiffening ribs, one end of each pair of stiffening ribs is connected to the bottom middle position of the spanning arm, another end extends to both sides separately from the lower end of the spanning arm separately, and bend and form a fixed foot; a bridge part is coated on the middle part of the support frame and the reinforcing ribs, the bottoms of the two sides of the bridge part respectively extend into a fixing block to be fixed on the circuit board, and the fixing pins of the support frame are respectively exposed out of the bottom of the fixing block to be welded on the circuit board; the pair of buckling blocks are respectively coated at two ends of the cross arm and respectively form a positioning groove facing the joint to fix the rear edge of the electronic card, wherein the bottom of the bridging part forms an elevated space for arranging electronic components.

Description

The bayonet connector bolt lock structure

Technical field

The utility model relates to a kind of bayonet connector bolt lock structure, refers to the bolt lock structure (latch) in a kind of bayonet connector especially, in order to cooperate an electrical joint fixing one electronic cards edge in this bayonet connector.

Background technology

The main circuit board of electronic equipment is provided with different bayonet connectors and connects in order to the plant that various modular electronic cards are provided, make electrical contact on the lateral margin of being located at each electronic cards can electrically contact the conducting terminal of each corresponding bayonet connector, to realize electrically conducting between these electronic cards and this main circuit board.Each electronic cards need be immobilizated in each corresponding bayonet connector reliably, just can guarantee the stable contact between electrical contact and the conducting terminal.Therefore, bayonet connector is except comprising that one has the joint of conducting terminal, and further comprises the bolt lock structure of a fixing electronic cards.

Existing bayonet connector bolt lock structure, as be disclosed in a kind of " card edge connector latch " that People's Republic of China's patent publication No. CN1523714A a case on August 25th, 2004 is disclosed, its be one by stamping forming metal breech lock.Above-mentioned prior art is in order to be anchored on breech lock on the circuit board, and the both sides of this breech lock and middle part respectively are provided with a plate secure component, and is connected on the circuit board through the mode of welding.

The bayonet connector bolt lock structure of above-mentioned prior art has taken the great space of circuit board, and the circuit board of being not only the electronic cards below is restricted on laying (layout) electronic building brick; In addition, the plate secure component in the middle of the fixed form of this existing breech lock, particularly breech lock makes the bottom space of breech lock also be restricted on the electronic building brick layout.

Therefore, as from the foregoing, above-mentioned existing bayonet connector breech lock in practical application, obviously has inconvenience and exists with defective, and can treat in addition improver.

Summary of the invention

Main purpose of the present utility model is to provide a kind of bayonet connector bolt lock structure, makes the circuit board of bayonet connector below be convenient to lay electronic building brick.

Another purpose of the present utility model is to provide a kind of bayonet connector bolt lock structure, improves and increase the structural strength of breech lock, breech lock is fixed in the position, both sides on the circuit board, more convenient laying electronic building brick in the mode of cross-over connection.

A purpose more of the present utility model is to provide a kind of bayonet connector bolt lock structure, makes with the flush type ejection forming technique one-body moldedly and finishes the bayonet connector bolt lock structure, to reduce number of assembling steps and faster production.

For achieving the above object, the utility model bayonet connector bolt lock structure, be installed on the trailing edge that inserts the back electronic cards on the circuit board with fixing one with the joint of this bayonet connector, the leading edge of this electronic cards is inserted in this joint, includes a metal supporting frames, a bridge formation portion and a pair of buckle piece.This metal supporting frames includes one across arm and a pair ofly generally be tabular ribs, this generally be vertical with this across arm to ribs, one end of every pair of ribs is connected in this middle part across arm, and the other end extend to both sides across arm discretely along being somebody's turn to do respectively, and was bent to form a fixing feet; This bridge formation portion coats the middle part of this bracing frame and this to ribs, and this bridge formation portion each one of two side bottoms is extended a fixed block, and in order to being fixed on the circuit board, and this exposes to the bottom of this fixed block respectively to fixing feet, in order to be welded in circuit board; This is coated on this two ends across arm separately to the buckle piece, and forms one respectively towards the location notch of this joint trailing edge with this insertion back electronic cards of fixing, and wherein should bridge formation portion bottom forming one can be for the frame high spatial of laying electronic building brick.

The utility model is compared prior art, makes bayonet connector and the circuit board that is positioned at its below have a high space, is convenient to lay electronic building brick; And breech lock is fixed on the circuit board in the mode of cross-over connection, the unsettled and vacant circuit board in the centre of breech lock, the laying of more convenient electronic building brick.

Description of drawings

Fig. 1 is installed on the vertical view of a circuit board for the utility model bayonet connector bolt lock structure.

Fig. 2 is the three-dimensional exploded view of the utility model bayonet connector bolt lock structure.

Fig. 2 A is the stereogram of bracing frame in the utility model bayonet connector bolt lock structure.

Fig. 3 is the three-dimensional exploded view of another angle of the utility model bayonet connector bolt lock structure.

Fig. 3 A is the stereogram of another angle of bracing frame in the utility model bayonet connector bolt lock structure.

Fig. 4 is the rearview of bracing frame and jetting mold in the utility model bayonet connector bolt lock structure.

Fig. 5 is the cutaway view along 5-5 hatching among Fig. 4.

Fig. 6 cooperates the three-dimensional combination figure of a joint fixing electronic cards for the utility model bayonet connector bolt lock structure.

Fig. 7 is fixed in the front view of circuit board for the utility model bayonet connector bolt lock structure.

Fig. 8 is fixed in the rearview of circuit board for the utility model bayonet connector bolt lock structure.

Fig. 9 is fixed in the end view of circuit board for the utility model bayonet connector bolt lock structure.

Figure 10 is the stereogram of the utility model bayonet connector bolt lock structure SMD LED surface-mount device LED embodiment depression angle.

Figure 11 looks up the stereogram of angle for the utility model bayonet connector bolt lock structure SMD LED surface-mount device LED embodiment.

Figure 12 is the upward view of the utility model bayonet connector bolt lock structure SMD LED surface-mount device LED embodiment.

Embodiment

See also Fig. 1, be installed on the vertical view of a circuit board for the utility model bayonet connector bolt lock structure.The utility model provides the joint 200 of a kind of bayonet connector bolt lock structure 100 (or be called for short breech lock) and this bayonet connector to be installed on the circuit board 300 trailing edge with fixing one electronic cards 400.The leading edge of this electronic cards 400 is inserted in this joint 200.This joint 200 has an insulating body 202 and plurality of terminals 204,206, this terminal 204,206 is fixed on this insulating body 202, the one end is welded on this circuit board 300, and the other end extends in this insulating body 200 to be electrically connected at the electronic cards 400 after this insertion.

See also Fig. 2 to Fig. 3, be respectively the three-dimensional exploded view of the different angles of the utility model bayonet connector bolt lock structure.This bayonet connector bolt lock structure 100 includes a snap close piece 10, a bracing frame 20, reaches a stop part 30.

This snap close piece 10 includes a bridge formation portion 12, reaches a pair of buckle piece 14a, 14b.This is positioned at the both sides of this bridge formation portion 12 to buckle piece 14a, 14b, towards this joint 200 and form the trailing edge of a location notch 140 with this electronic cards 400 of fixing respectively, two side bottoms of this snap close piece 10 respectively protrude a fixed leg 172 and are fixed on this circuit board 300 to the front end of buckle piece 14a, 14b for this.This bridge formation portion 12 of this snap close piece 10 has a body piece 13, a pair of cladding plate 15, reaches a pair of fixed block 17.This body piece 13 protrudes from this centre to cladding plate 15, and this respectively is formed at this exterior bottom to cladding plate 15 to fixed block 17, and wherein this is to be located at this bottom to fixed block 17 accordingly to fixed leg 172.

Wherein this snap close piece 10 is formed with a pair of dashpot 170, this is formed at this to fixed block 17 and this is between buckle piece 14a, the 14b separately to dashpot 170, by this can be for this space that has buffering to pull to buckle piece 14a, 14b, so that this location notch 140 leaves the edge of this electronic cards 400 and withdraws from this electronic cards 400.

This is convexly equipped with a hook part 142 that is positioned at these location notch 140 tops, an and bearing and leaning portion 144 that is positioned at these location notch 140 belows towards this joint 200 separately to buckle piece 14a, 14b.In the present embodiment, further each is convexly equipped with a lateral retaining wall 146 that connects this bearing and leaning portion 142 and this hook part 144 towards this joint 200 to buckle piece 14a, 14b for this, the side of the electronic cards 400 after this lateral retaining wall 146 blocks this respectively and plugs.For conveniently fixing this electronic cards 400, wherein this this bearing and leaning portion 142 to buckle piece 14a, 14b preferably is provided with a guiding incline 143 towards this joint 200.This guiding incline 143 can be guided this electronic cards 400 and is fixed in smoothly in this location notch 140.In addition, this respectively has a flank 148 to buckle piece 14a, 14b rear end, and this flank 148 is connected in corresponding this hook part 142 and this bearing and leaning portion 144, and this flank 148 extends back to this joint 200.In moving back the card process, develop circuit board to guarantee this bottom surface by this flank 148,, because of torsion produces inclination, avoid this electronic cards 400 to be related to and the unfavorable card that moves back when preventing to pivot by card to produce stabilization to buckle piece 14a, 14b.

Please cooperate simultaneously with reference to figure 2A and Fig. 3 A, be respectively the stereogram of bracing frame different angles in the utility model bayonet connector bolt lock structure.This bracing frame 20 is also to bend the mode that forms and penetrate with the flush type plastics by metallic plate through punching press to be embedded in this snap close piece 10.This bracing frame 20 includes one across arm 22 and a pair of ribs 24a, 24b.Should be across partly being embedded in this bridge formation portion 12 in the middle of the arm 22, and its two ends are embedded in this respectively in buckle piece 14a, the 14b, wherein should bridge formation portion 12 coat this across the middle part of arm 22 and this is to ribs 24a, 24b.This generally is tabular to ribs 24a, 24b and generally is vertical with this across arm 22, the end of each this ribs 24a, 24b be connected across arm 22 middle parts with this, the other end extends to form a horizontal part 242 across arm 22 both sides discretely to this respectively, and the other end of this horizontal part 242 is that free end is to form a downward fixing feet 244.

This this fixing feet 244 to ribs 24a, 24b extend downward vertically and expose to these 12 liang of side bottoms of bridge formation portion this to fixed block 17 to be welded in circuit board.In the present embodiment, this of this snap close piece 10 respectively is provided with a welding groove 176 (as shown in Figure 3) to fixed block 17 bottoms, and this of this bracing frame 20 is to fixing feet 244 each corresponding this welding groove 176 that expose to.This welding groove 176 can hold scolding tin by this, and this fixing feet 244 can be fixed on this circuit board 300 by surface mount technology (SMT), can certainly be fixed on this circuit board 300 with through hole solder technology (THT).

In the present embodiment, this bracing frame 20 should respectively be extended with on one tabs 222 and tabs 224 once towards this joint 200 across the upper and lower edge in the two ends of arm 22, tabs 222 and this time tabs 224 are embedded in corresponding this this hook part 142 and this bearing and leaning portion 144 to buckle piece 14a, 14b separately on this.Wherein this bracing frame 20 should preferably be further respectively to have a side tabs 226 across the two ends lateral margin of arm 22, and this side tabs 226 extends and is embedded in this this lateral retaining wall 146 to buckle piece 14a, 14b towards this joint 200.Can strengthen the structural strength of this buckle piece 14a, 14b by the reinforcement of above-mentioned this bracing frame 20, to increase the service life.

Please consult Fig. 4 and Fig. 5 again, be divided into the rearview of bracing frame and jetting mold in the utility model bayonet connector bolt lock structure, and along the cutaway view of 5-5 hatching among Fig. 4.In the technology of flush type ejection formation, the part of this bracing frame 20 be clamping in a jetting mold 500, again plastics are penetrated in cavity.The fluid that inject this moment can produce great impulsive force, these fixing feet 244 as easy as rolling off a log generation displacements of this bracing frame 20 and not in the tram.Therefore in the present embodiment, this of this bracing frame 20 respectively is provided with at least one clamping breach 246 to fixing feet 244 both sides, and in a pair of anchor clamps 501,502 of this mould 500, respectively form the grip block 503,504 of corresponding this clamping breach 246, grip this fixing feet 244 by this and keep out the impulsive force of plastics when penetrating.

Please consult Fig. 2 to Fig. 3 again, the utility model bayonet connector bolt lock structure 100 be prevent that the user from excessively pulling and structure fixing, further be provided with this stop part 30.This stop part 30 is to be fixed on this circuit board 300, and this stop part 30 includes a top board 32, a backboard 34, reaches a pair of front apron 36.

This backboard 34 is positioned at the rear end of this snap close piece 10, and this backboard 34 and this are across forming a gap between the arm 22.Each extends a back stator 342 downwards two sides of this backboard 34, the rear end, both sides of this snap close piece 10 respectively forms the back fixed groove 178 (as shown in Figure 3) of corresponding this back stator 342, and this back stator 342 is connected to the rear side of this snap close piece 10 by this corresponding back fixed groove 178 and is fixed on this circuit board 300.Can strengthen fixing this snap close piece 10 by this.In the present embodiment, for fixing this backboard 34 in this bridge formation portion 12, form a back snap-latch piece 344 in the middle of this backboard 34, this body piece 13 of this bridge formation portion 12 forms a corresponding clamping groove 134 that is somebody's turn to do back snap-latch piece 344, and this back snap-latch piece card 344 is gone in this clamping groove 134 of this bridge formation portion 12.

This top board 32 is to be extended towards this joint 200 by the top of this backboard 34, this top board 32 has a pair of preceding stator 322 that is extended by its both sides downwards, the both sides front end of this snap close piece 10 respectively forms a corresponding preceding fixed groove 174 (as shown in Figure 2) that is somebody's turn to do preceding stator 322, and this is connected to the front side of this snap close piece 10 to preceding stator 322 by this corresponding this prelocalization groove 174 and is fixed on this circuit board 300.In the present embodiment, this stop part 30 should be to preceding stator 322 be to take the form of inclined plane, and this snap close piece 10 should before fixed groove 174 also have an inclined-plane, this to preceding stator 322 oblique separately be connected to this snap close piece 10 should before in the fixed groove 174.The preceding stator 322 of this inclined plane shape can provide side direction and block strength backward on horizontal plane by this.In addition, this respectively has a block platform 145 that protrudes to the inside to buckle piece 14a, 14b, this is to be positioned at this top to fixed block 17 to block platform 145, and this is to oblique separately this block platform 145 that is connected to this to buckle piece 14a, 14b of preceding stator 322.Stator 322 produces the function of spacing and block simultaneously before being somebody's turn to do by this to this buckle piece 14a, 14b.

In addition, extend one downwards in the middle of this top board 32 of this stop part 30 before snap-latch pieces 324, this preceding snap-latch piece 324 and this backboard 34 are relative and be fastened on these bridge formation portion 12 front ends of this snap close piece 10.In particular, this preceding snap-latch piece 324 forms a block button hole 326, and corresponding this block button hole 326 of these body piece 13 front ends of this bridge formation portion 12 forms a buckle piece 132 should preceding snap-latch piece 324 to fasten.By this should before snap-latch piece 324 cooperate the clamping should bridge formation portion 12 with this back snap-latch piece 344, and should bridge formation portion 12 as hanging this on preceding snap-latch piece 324, more strengthen the intensity of these snap close piece 10 two ends across the formula structure.

This of this stop part 30 is to be extended downwards and respectively blocked this place ahead to cladding plate 15 in this snap close piece 10 by the leading edge of this top board 32 to front apron 36.One side can be protected being somebody's turn to do across arm 22 of exposing, and another side also has effect attractive in appearance.

When dismounting during this electronic cards 400, only need pull this backward to buckle piece 14a, 14b, move to discharge the trailing edge of this electronic cards 400 after making this location notch 140.This moment, the back catch 34 of this stop part 30 can avoid this snap close piece 20 to be pulled excessively backward.

See also Figure 10 to Figure 12, be respectively stereogram and the upward view of the utility model bayonet connector bolt lock structure SMD LED surface-mount device LED embodiment.In the foregoing description, the form that stator 322 and this back stator 342 are through hole solder technology (THT) before this of this stop part 30.Yet the utility model also can application surface mount technology (SMT).As shown in the figure, this embodiment provides a kind of bayonet connector bolt lock structure 100 ' to have a snap close piece 10 ' and a stop part 30 ' is embedded with a bracing frame (not icon).This snap close piece 10 ' has a bridge formation portion 12 and is formed with a preceding clamping groove 121 and a back clamping groove 122.The preceding stator 323 that this stop part 30 ' has snap-latch piece 327 and a back snap-latch piece 347 before one in the middle of being positioned at, an a pair of SMT form respectively be bent with a horizontal leg 325, and the back stator 343 of a pair of SMT form respectively be bent with a horizontal leg 345.Wherein be somebody's turn to do the bottom surface that preceding snap-latch piece 327 and this back snap-latch piece 347 are sticked in this preceding clamping groove 121 and this back clamping groove 122 respectively and surpass this bridge formation portion 12 substantially, this bayonet connector bolt lock structure 100 ' can utilize surface mount technology to be welded on the circuit board by this.

The utility model bayonet connector bolt lock structure 100 is characterised in that with flush type ejection formation and integrated technology, improve and increase the structural strength of breech lock, not only make breech lock partly be fixed in two ends on the circuit board in the mode of cross-over connection, with convenient laying electronic building brick, and can reduce number of assembling steps and faster production.Particularly be to improve the structure of this bracing frame 20 and this snap close piece 10.This of this bracing frame 20 strengthened overall structure to ribs 24a, 24b, makes the centre of breech lock can not design any fixture, and is fixed on circuit board with the two ends cross connection type.In addition, this stop part 30 provides position limitation protection function, and the fixed function of breech lock.

By above-mentioned description, the utility model particularly thereunder circuit board has characteristics and the function that convenient electronic building brick is laid.See also Fig. 6, cooperate the three-dimensional combination figure of a joint fixing electronic cards for the utility model bayonet connector bolt lock structure.The utility model bayonet connector bolt lock structure 100 cooperates through choosing high this joint 200 and terminal 204 thereof, increases the space between this circuit board 300 and this electronic cards 400, forms a high spatial 302.This high spatial 302 is to be convenient to lay electronic building brick.

Seeing also Fig. 7 to Fig. 9, is respectively front view, rearview and end view that the utility model bayonet connector bolt lock structure is fixed in circuit board.Above-mentioned each figure shows 100 cross-over connections of the utility model bayonet connector bolt lock structure on this circuit board 300, and the position, intermediate portion does not have the extension downwards of any pin and is fixed in circuit board.Produce another high spatial 304 between bayonet connector bolt lock structure 100 of the present utility model and this circuit board 300, these high spatial 304 centres are convenient to lay electronic building brick without any blocking.

Claims (21)

1, a kind of bayonet connector bolt lock structure is installed on the trailing edge that inserts the back electronic cards on the circuit board with fixing one with the joint of this bayonet connector, and the leading edge of this electronic cards is inserted in this joint, it is characterized in that, comprising:

One metal supporting frames, include one across arm and a pair ofly generally be tabular ribs, this to ribs with should generally be vertical across arm, an end of every pair of ribs is connected in this middle part across arm, the other end extend to both sides across arm discretely along being somebody's turn to do respectively, and was bent to form a fixing feet;

One bridge formation portion coats the middle part of this bracing frame and this to ribs, and this bridge formation portion each one of two side bottoms is extended a fixed block, and in order to being fixed on the circuit board, and this exposes to the bottom of this fixed block respectively to fixing feet, in order to be welded in circuit board; And

A pair of buckle piece is coated on this two ends across arm separately, and forms one respectively towards the location notch of this joint trailing edge with this insertion back electronic cards of fixing, and wherein should bridge formation portion bottom forming one can be for the frame high spatial of laying electronic building brick.

2, bayonet connector bolt lock structure according to claim 1, it is characterized in that: this respectively has a horizontal part to ribs, one end of this horizontal part is connected in this across part in the middle of the bottom of arm, and the other end of this horizontal part is a free end, and this fixing feet is extended downwards by this free end.

3, bayonet connector bolt lock structure according to claim 2, it is characterized in that: this bridge formation portion of this snap close piece has a body piece and a pair of cladding plate, this body piece coats the partly middle of this bracing frame, this extends and coats this horizontal part of this ribs to cladding plate by these body piece two side bottoms, but wherein should expose to the both sides and the resilient movement of this body piece across the arm both sides.

4, bayonet connector bolt lock structure according to claim 3 is characterized in that: this respectively is connected in this exterior bottom to cladding plate to fixed block, and respectively protrudes a downward fixed leg to be fixed on the circuit board.

5, bayonet connector bolt lock structure according to claim 2 is characterized in that: this of this snap close piece respectively is provided with a welding groove to the fixed block bottom, and this of this bracing frame is to each corresponding this welding groove that exposes to of fixing feet.

6, bayonet connector bolt lock structure according to claim 1 is characterized in that: this is convexly equipped with a hook part that is positioned at this location notch top, an and bearing and leaning portion that is positioned at this location notch below towards this joint separately to the buckle piece.

7, bayonet connector bolt lock structure according to claim 6, it is characterized in that: this bracing frame should across the upper and lower edge in the two ends of arm respectively have on one tabs and once tabs extend towards this joint, tabs and this time tabs are embedded in corresponding this hook part and this bearing and leaning portion separately on this.

8, bayonet connector bolt lock structure according to claim 6 is characterized in that: this this bearing and leaning portion to the buckle piece is provided with a guiding incline towards this joint.

9, bayonet connector bolt lock structure according to claim 6 is characterized in that: this respectively has a flank to the buckle piece and is connected in corresponding this bearing and leaning portion and this hook part, and this flank is towards this joint direction extension dorsad.

10, bayonet connector bolt lock structure according to claim 6 is characterized in that: further each is convexly equipped with a lateral retaining wall that connects this bearing and leaning portion and this hook part towards this joint to the buckle piece for this, the side of the electronic cards after this lateral retaining wall blocks this respectively and plugs.

11, bayonet connector bolt lock structure according to claim 10 is characterized in that: this bracing frame should respectively have a side tabs across the two ends lateral margin of arm, this side tabs extends and is embedded in this lateral retaining wall towards this joint.

12, bayonet connector bolt lock structure according to claim 1 is characterized in that: this of this bracing frame respectively is provided with the clamping breach of at least one cooperation mould to the fixing feet both sides.

13, bayonet connector bolt lock structure according to claim 1, it is characterized in that: further have a stop part and be fixed on this circuit board, this stop part has the rear end that a backboard is positioned at this snap close piece, and this backboard and this are across forming a gap between the arm.

14, bayonet connector bolt lock structure according to claim 13, it is characterized in that: each extends a back stator downwards two sides of this backboard of this stop part, the rear end, both sides of this snap close piece respectively forms the back fixed groove of corresponding this back stator, and this back stator is connected to the rear side of this snap close piece by this corresponding back fixed groove and is fixed on this circuit board.

15, bayonet connector bolt lock structure according to claim 14 is characterized in that: this back stator is to be welded on this circuit board with through hole solder technology or surface mount technology.

16, bayonet connector bolt lock structure according to claim 13, it is characterized in that: form a back snap-latch piece in the middle of this backboard of this stop part, this bridge formation portion forms the clamping groove of corresponding this back snap-latch piece, and this back snap-latch piece snaps in this clamping groove of this bridge formation portion.

17, bayonet connector bolt lock structure according to claim 13, it is characterized in that: this stop part has a top board, this top board is extended towards this joint by the top of this backboard, this top board has a pair of preceding stator that is extended by its both sides downwards, the both sides front end of this snap close piece respectively forms a corresponding preceding fixed groove that is somebody's turn to do preceding stator, and this is connected to the front side of this snap close piece to preceding stator by this corresponding this prelocalization groove and is fixed on this circuit board.

18, bayonet connector bolt lock structure according to claim 17 is characterized in that: this preceding stator is to be welded on this circuit board with through hole solder technology or surface mount technology.

19, bayonet connector bolt lock structure according to claim 17, it is characterized in that: being somebody's turn to do of this stop part take the form of inclined plane to preceding stator, and this snap close piece should also have an inclined-plane by preceding fixed groove, and this is connected in the preceding fixed groove of being somebody's turn to do of this snap close piece preceding stator is oblique separately.

20, bayonet connector bolt lock structure according to claim 19, it is characterized in that: each protrudes a corresponding block platform that is somebody's turn to do preceding stator to this of this snap close piece to the inside to the buckle piece, this is to be positioned at this top to fixed block to the block platform, and should preceding this block platform of the oblique block of stator.

21, bayonet connector bolt lock structure according to claim 17 is characterized in that: snap-latch piece before extending downwards in the middle of this top board of this stop part, this preceding snap-latch piece is relative with this backboard and be fastened on the front end of this bridge formation portion of this snap close piece.

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