Large-current board-to-board electric connector

Abstract

The electric connector male seat is inserted into the electric connector female seat, the electric connector male seat comprises a male seat plastic body and a male seat metal terminal, and the male seat metal terminal and the male seat plastic body are formed into an integrated structure in an embedded injection mode; the electric connector female seat comprises a female seat plastic body and a female seat metal terminal, wherein the female seat metal terminal and the female seat plastic body are formed into an integrated structure in an embedded injection mode. An island is arranged in the middle of the electric connector female seat, an annular insertion cavity is formed around the outer side of the island, the electric connector male seat can be inserted into the annular insertion cavity, and a first retaining clamping protrusion is arranged on one side of the cavity wall, forming the annular insertion cavity, of the female seat metal terminal. And the male seat metal terminal is provided with a first clamping groove matched with the first retaining clamping bulge. According to the utility model, the capability of resisting large current can be improved, the forming process is simple, and the production cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric connectors, in particular to a high-current board-to-board electric connector. Background Art

[0002] Board-to-board connectors are a common connector product in the electronics market. Among various types of connector products, board-to-board connectors have the strongest transmission function and the widest application range. At present, with the trend of large-screen and integrated functions of smartphones, the battery life is questioned. At the same time, the charging speed of smartphones is not satisfactory, and many mobile phone functions require large instantaneous currents. Some customers require that the power terminals of battery board-to-board connectors can pass a current of up to 15A. Traditional battery board-to-board connectors are no longer suitable for market trends.

[0003] Therefore, technicians in this field have designed a variety of electrical connectors to increase the current passing through the power terminal, such as the board-to-board connector disclosed in patent publication number CN 104916936 B, in which the socket includes a socket body, a plurality of socket signal terminals mounted on the socket body, and a plurality of socket power terminals integrally formed on the socket body; the plug includes a plug body, a plurality of plug signal terminals integrally formed on the plug body, a plug power terminal, and a fixing plate; although this design scheme can increase the current passing through the power terminal in the electrical connector, there are still two problems with this scheme:

[0004] (1) In this solution, when the socket body and the plug body are in contact and connected at both ends, a fixed piece of the plug contacts the latching arms of the two socket power terminals to connect and connect. The contact area is small and the ability to resist excessive current is insufficient.

[0005] (2) In this solution, the power terminals and signal terminals at both ends are assembled with the plastic body using an assembly process, which has a complex manufacturing process. In addition, the connection strength between the power terminals, signal terminals and the plastic body during the assembly process is low. Stress, vibration or impact at the terminal welding site may cause the solder to crack and cause a conduction failure.

[0006] Therefore, it is necessary to provide a high-current board-to-board electrical connector to solve the above technical problems. Utility Model Content

[0007] The main purpose of the utility model is to provide a high-current board-to-board electrical connector, which can improve the ability to withstand high currents, and has a simple molding process and reduces production costs.

[0008] The utility model achieves the above-mentioned purpose through the following technical solutions: a high-current board-to-board electrical connector, which includes an electrical connector female seat and an electrical connector male seat inserted into the electrical connector female seat, the electrical connector male seat includes a male seat plastic body, and a male seat metal terminal that is embedded in the male seat plastic body and is integrally formed with the male seat plastic body by injection molding; the electrical connector female seat includes a female seat plastic body, and a female seat metal terminal that is embedded in the female seat plastic body and is integrally formed with the female seat plastic body by injection molding; an island is arranged in the middle of the electrical connector female seat, and an annular annular plug-in cavity is formed around the outer side of the island and is provided for the electrical connector male seat to be inserted, a first retaining protrusion is arranged on one side of the cavity wall of the annular plug-in cavity formed by the female seat metal terminal, and the male seat metal terminal is provided with a first card groove that cooperates with the first retaining protrusion.

[0009] Furthermore, the male socket of the electrical connector also includes a male socket protective armor embedded in the end of the male socket plastic body, and the socket protective armor includes a first embedded piece covering the upper surface of the two ends of the male socket plastic body, a second embedded piece extending downward from the front and rear sides of the first embedded piece and attached to the front and rear sides of the male socket plastic body, and a third embedded piece bent downwardly from the left or right side of the first embedded piece.

[0010] Furthermore, the middle part of the second embedding piece extends and is embedded in the male seat plastic body, and the bottom is provided with a first welding part that is bent and extends horizontally outward and extends from the front and rear surfaces of the male seat plastic body; the third embedding piece is provided with a second card slot, and the bottom of the third embedding piece extends and is embedded in the male seat plastic body, and the end of the bottom is provided with a second welding part that is bent and extends horizontally outward and extends from the left and right surfaces of the male seat plastic body.

[0011] Furthermore, the male socket metal terminal includes a fourth embedded piece covering the inner side of the male socket plastic body, a first connecting piece bent upward from the fourth embedded piece and covering the upper surface of the male socket plastic body, and a fifth embedded piece bent downward and covering the outer side of the male socket plastic body; the fifth embedded piece is provided with the first card slot, the middle part of the fifth embedded piece extends and is embedded in the male socket plastic body, and the bottom end is provided with a third welding part that is bent and extends horizontally outward and extends out of the front and rear surfaces of the male socket plastic body.

[0012] Furthermore, a plurality of accommodating grooves for accommodating the female socket metal terminals are arranged along the length direction on both sides of the island, and a plug-in groove adapted to the island of the female socket of the electrical connector is formed in the plastic body of the male socket.

[0013] Furthermore, the electrical connector socket also includes a socket protective armor embedded in the end of the socket plastic body, and the socket protective armors at both ends include a first socket protective armor and a second socket protective armor that are symmetrically arranged in structure.

[0014] Furthermore, the first protective armor of the mother seat and the second protective armor of the mother seat both include a sixth embedded piece covering the upper surface and the inner side of the plastic body of the mother seat and in contact and conduction with the third embedded piece, a seventh embedded piece bent downward from the sixth embedded piece and embedded into the end of the plastic body of the mother seat, a second connecting piece bent downward from the sixth embedded piece and extending into the annular plug-in cavity, and an eighth embedded piece horizontally bent from the seventh embedded piece to be embedded in the side of the plastic body of the mother seat.

[0015] Furthermore, the second connecting piece is provided with a first contact arm extending upward along the length direction and accommodated at one end of the island, and a second contact arm extending upward along the width direction and in contact and conduction with the second embedded piece; the sixth embedded piece is provided with a second stop protrusion extending into the second slot; the bottom of the seventh embedded piece is provided with a fourth welding portion that is bent and extends horizontally outward and extends out of the left and right surfaces of the plastic body of the mother seat; the upper end of the eighth embedded piece is covered on the upper surface of the plastic body of the mother seat, and the lower end is provided with a fifth welding portion that is bent and extends horizontally outward and extends out of the front and rear surfaces of the plastic body of the mother seat.

[0016] Furthermore, the female socket metal terminal includes a ninth embedded piece covering the inner side of the female socket plastic body and in contact with the fifth embedded piece, a third connecting piece bent and extended horizontally from the ninth embedded piece and constituting the cavity wall of the annular plug-in cavity, a third contact arm bent upward from the third connecting piece and extended into the accommodating groove and in contact with the fourth embedded piece, a fourth connecting piece bent upward from the ninth embedded piece and covering the upper surface of the female socket plastic body, and a tenth embedded piece bent downward from the ninth embedded piece and extended and embedded in the female socket plastic body.

[0017] Furthermore, the ninth embedding piece is provided with the first retaining protrusion; the bottom of the tenth embedding piece is provided with a sixth welding portion which is bent and horizontally extends outward and extends out of the front and rear surfaces of the plastic body of the female seat.

[0018] Compared with the prior art, the utility model has the following beneficial effects: (1) the first retaining protrusion is buckled into the first slot to make the surface of the male metal terminal contact and conduct with the surface of the female metal terminal, and the second retaining protrusion is buckled into the second slot to make the surface of the male protective armor contact and conduct with the surface of the female protective armor, and the male protective armor and the female protective armor are both designed to be widened, which can increase the contact area between the male and female electrical connectors at both ends, improve the current flow and thus increase the ability to resist overcurrent; (2) the protective armor and metal terminals of the female and male electrical connectors are all made of Insert The insert molding process and the plastic body molding are an integrated structure. Compared with the assembly molding process of the protective armor and the plastic body in the traditional connector, the process is simpler, and the connection strength between the protective armor and the plastic body is higher, and there will be no loosening; (3) The protective armor and metal terminals of the female connector and the male connector are stamped and formed as a whole and are symmetrically embedded on both sides of the plastic body. Only one stamping mold is needed, which saves the stamping mold, simplifies the assembly molding process, and reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the three-dimensional structure of a high-current board-to-board connector according to an embodiment of the utility model;

[0020] Figure 2 This is a schematic diagram of the exploded three-dimensional structure of a high-current board-to-board connector according to an embodiment of the utility model;

[0021] Figure 3 This is a schematic diagram of the three-dimensional structure of the electrical connector male socket of the embodiment of the utility model;

[0022] Figure 4 This is a schematic diagram of the exploded three-dimensional structure of the electrical connector male socket of the embodiment of the utility model;

[0023] Figure 5 This is a schematic diagram of the three-dimensional structure of the male socket protective armor and the male socket metal terminal according to the embodiment of the utility model;

[0024] Figure 6 This is a schematic diagram of the three-dimensional structure of the male seat protective armor according to an embodiment of the utility model;

[0025] Figure 7 This is a schematic diagram of the three-dimensional structure of the male metal terminal of the embodiment of the utility model;

[0026] Figure 8 This is a schematic diagram of the three-dimensional structure of the female socket of the electrical connector according to the embodiment of the utility model;

[0027] Fig. 9This is a schematic diagram of the exploded three-dimensional structure of the female socket of the electrical connector according to the embodiment of the utility model;

[0028] Fig.10 This is a schematic diagram of the three-dimensional structure of the female base protective armor and the female base metal terminal according to the embodiment of the utility model;

[0029] Fig.11 This is a schematic diagram of the three-dimensional structure of the mother seat protective armor of the embodiment of the utility model;

[0030] Fig.12 This is a schematic diagram of the three-dimensional structure of the female metal terminal of the embodiment of the utility model;

[0031] The numbers in the figure represent:

[0032] 100-high current board-to-board connector, 200-electrical connector male socket, 300-electrical connector female socket;

[0033] 1-male plastic body, 11-plug slot;

[0034] 2-male protective armor, 21-first embedded piece, 22-second embedded piece, 221-first welding part, 23-third embedded piece, 231-second slot, 232-second welding part;

[0035] 3-male metal terminal, 31-fourth embedded piece, 32-first connecting piece, 33-fifth embedded piece, 331-third welding part, 332-first slot;

[0036] 4- female plastic body, 41- annular plug-in cavity, 42- island, 43- receiving groove;

[0037] 5- mother base protective armor, 51- mother base first protective armor, 52- mother base second protective armor, 53- second connecting piece, 531- first contact arm, 532- second contact arm, 54- sixth embedded piece, 541- second stopper, 55- seventh embedded piece, 551- fourth welding part, 56- eighth embedded piece, 561- fifth welding part;

[0038] 6-female metal terminal, 61-ninth embedded piece, 611-first retaining protrusion, 62-third connecting piece, 63-third contact arm, 64-fourth connecting piece, 65-tenth embedded piece, 651-sixth welding part. DETAILED DESCRIPTION

[0039] Please refer to Figure 1-Figure 12 The present embodiment is a high-current board-to-board electrical connector. The high-current board-to-board electrical connector 100 includes an electrical connector female socket 300 and an electrical connector male socket 200 inserted into the electrical connector female socket 300 and electrically connected to the electrical connector female socket 300.

[0040] The electrical connector male socket 200 includes a male socket plastic body 1 , a male socket protective armor 2 which is formed as an integral structure with the male socket plastic body 1 by injection molding, and a male socket metal terminal 3 .

[0041] The male plastic body 1 is in a rectangular frame shape, and a plugging slot 11 for plugging with the female socket 300 of the electrical connector is formed in the male plastic body 1 .

[0042] The male seat protective armor 2 is covered on the outer peripheral surfaces of the left and right ends of the male seat plastic body 1. The male seat protective armor 2 includes a first embedding piece 21 covering the upper surface of the two ends of the male seat plastic body 1, a second embedding piece 22 extending downward from the front and rear sides of the first embedding piece 21 and attached to the front and rear sides of the end of the male seat plastic body 1, and a third embedding piece 23 bent downwardly and formed on the left or right side of the first embedding piece 21.

[0043] The middle part of the second embedding piece 22 extends and is embedded in the male plastic body 1, and the bottom of the second embedding piece 22 is provided with a first welding portion 221 that is bent and extends horizontally outward and extends out of the front and rear surfaces of the male plastic body 1; the third embedding piece 23 is provided with a second card groove 231, the bottom of the third embedding piece 23 extends and is embedded in the male plastic body 1, and the bottom end of the third embedding piece 23 is provided with a second welding portion 232 that is bent and extends horizontally outward and extends out of the left and right surfaces of the male plastic body 1.

[0044] The male metal terminal 3 includes a fourth embedded piece 31 covering the inner side of the male plastic body 1 and constituting the cavity wall of the second plug-in cavity 11, a first connecting piece 32 bent upward from the fourth embedded piece 31 to cover the upper surface of the male plastic body 1, and a fifth embedded piece 33 bent downward to cover the outer side of the male plastic body 1. The fourth embedded piece 31, the first connecting piece 32 and the fifth embedded piece 33 together form an "n"-shaped structure embedded in the male plastic body 1.

[0045] The fifth embedding piece 33 is provided with a first slot 332 , the bottom of the fifth embedding piece 33 extends and is embedded in the male plastic body 1 , and the bottom end of the fifth embedding piece 33 is provided with a third welding portion 331 that is bent and extends horizontally outward and extends out of the front and rear surfaces of the male plastic body 1 .

[0046] The electrical connector female socket 300 includes a female socket plastic body 4 , a female socket protective armor 5 which is formed as an integral structure with the female socket plastic body 1 by injection molding, and a female socket metal terminal 6 .

[0047] The female plastic body 4 is in the shape of a rectangular frame, and an upwardly protruding island 42 is provided in the middle of the female plastic body 4. An annular plug-in cavity 41 is formed around the outer side of the island 42 and into which the power supply connector male socket 200 is inserted. A plurality of accommodating grooves 43 for accommodating the female metal terminals 6 are provided on both sides of the island 42 along the length direction.

[0048] The mother seat protection armor 5 is covered on the outer peripheral surfaces of the left and right ends of the mother seat plastic body 4. The mother seat protection armor 5 at both ends includes a symmetrically arranged mother seat first protection armor 51 and a mother seat second protection armor 52. The structure of the mother seat first protection armor 51 and the mother seat second protection armor 52 is the same and both include a sixth embedded piece 54 covering the upper surface and the inner side of the mother seat plastic body 4 and contacting and conducting with the third embedded piece 23, a seventh embedded piece 55 bent downward from the sixth embedded piece 54 and embedded in the end of the mother seat plastic body 4, a second connecting piece 53 bent downward from the sixth embedded piece 54 and extending into the annular plug-in cavity 41 in the mother seat plastic body 4, and an eighth embedded piece 56 horizontally bent from the seventh embedded piece 55 to be embedded in the side of the mother seat plastic body 4.

[0049] The bottom end of the seventh embedded piece 55 is provided with a fourth welding portion 551 that is bent and extends horizontally outward and extends out of the left and right surfaces of the mother plastic body 4; the upper end of the eighth embedded piece 56 is covered on the upper surface of the mother plastic body 4, and the lower end is provided with a fifth welding portion 561 that is bent and extends horizontally outward and extends out of the front and rear surfaces of the mother plastic body 4.

[0050] The second connecting piece 53 is provided with a first contact arm 531 extending upward along the length direction and accommodated at one end of the island 42, and a second contact arm 532 extending upward along the width direction and in contact and conducting with the second embedded piece 22; the supporting enclosure of the first contact arm 531 can ensure the stability of the male socket 200 of the electrical connector when inserted into the first plug-in cavity 41; the contact point bent inwardly provided on the second contact wall 532 can ensure the increase of the holding force between the first contact arm 531 and the second embedded piece 22, thereby ensuring the stability of the contact.

[0051] The sixth embedded piece 54 is provided with a second retaining protrusion 541 which is snapped into the second slot 231 on the third embedded piece 23. On the one hand, after the second retaining protrusion 541 is snapped into the second slot 231, it can prevent the male connector 200 from vertically detaching from the female connector 300. On the other hand, after the second retaining protrusion 541 is snapped into the second slot 231, the third embedded piece 23 can be completely in contact with the surface of the sixth embedded piece 54, so that the surface of the male seat protective armor 2 is in contact with the surface of the female seat protective armor 5, and the male seat protective armor 2 and the female seat protective armor 5 are both designed to be widened, which can increase the contact area between the male connector 200 and the female connector 300 at both ends, improve the current flowability and thus increase the overcurrent capacity.

[0052] The female socket metal terminal 6 includes a ninth embedded piece 61 covering the inner side of the female socket plastic body 4 and in contact with the fifth embedded piece 33, a third connecting piece 62 bent and horizontally extended from the ninth embedded piece 61 and constituting the cavity wall of the annular plug-in cavity 41, a third contact arm 63 bent upward from the third connecting piece 62 and extended into the accommodating groove 43 and in contact with the fourth embedded piece 31, a fourth connecting piece 64 bent upward from the ninth embedded piece 61 and covering the upper surface of the female socket plastic body 4, and a tenth embedded piece 65 bent downward from the ninth embedded piece 61 and embedded in the female socket plastic body 4, and a sixth welding portion 651 bent and extended horizontally outward and protruding from the front and rear surfaces of the female socket plastic body 4 is provided at the bottom of the tenth embedded piece 65.

[0053] The ninth embedded piece 61 is provided with a first retaining protrusion 611 which is snapped into the first slot 332 on the fifth embedded piece 33. On the one hand, after the first retaining protrusion 611 is snapped into the first slot 332, it can prevent the male connector 200 from vertically detaching from the female connector 300. On the other hand, the first retaining protrusion 611 is snapped into the first slot 332, which can make the ninth embedded piece 61 completely contact with the surface of the fifth embedded piece 33, so that the surface of the male metal terminal 6 is completely contacted and conductive with the surface of the female metal terminal 3, which can increase the contact area between the male connector 200 and the female connector 300 on both sides, improve the current flowability and thus increase the overcurrent capacity.

[0054] When the male connector 200 is inserted into the female connector 300, the male connector 200 is completely inserted into the first plug-in cavity 41 and the plug-in slot 11 is adapted to the island 42. Compared with the comparative document, the first stop-retraction protrusion 611 provided in the present solution is buckled into the first slot 332 so that the surface of the male metal terminal 6 is in contact with the surface of the female metal terminal 3, and the second stop-retraction protrusion 541 is buckled into the second slot 231 so that the surface of the male protective armor 2 is in contact with the surface of the female protective armor 5, and the male protective armor 2 and the female protective armor 5 are both designed to be widened, which can increase the contact area between the male connector 200 and the female connector 300 at both ends, and can improve the current flowability and thus increase the ability to resist overcurrent; the protective armor and metal terminals of the female connector 300 and the male connector 200 are both Insert The molding process and the plastic body are formed into an integrated structure. Compared with the assembly molding process of the protective armor and the plastic body in the traditional connector, the process is simpler, and the connection strength between the protective armor and the plastic body is higher, and no loosening will occur; the protective armor and the metal terminals of the electrical connector female seat 300 and the electrical connector male seat 200 are integrally stamped and symmetrically embedded on both sides of the plastic body, and only one stamping mold is needed, which saves the stamping mold, simplifies the assembly molding process, and reduces the production cost.

[0055] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A high current board-to-board electrical connector, characterized in that: It includes an electric connector female seat and an electric connector male seat inserted into the electric connector female seat, the electric connector male seat includes a male seat plastic body, and a male seat metal terminal which is embedded in the male seat plastic body and is integrally formed with the male seat plastic body by injection molding; the electric connector female seat includes a female seat plastic body, and a female seat metal terminal which is embedded in the female seat plastic body and is integrally formed with the female seat plastic body by injection molding; an island is arranged in the middle of the electric connector female seat, and an annular annular plug-in cavity is formed around the outer side of the island and is provided for the electric connector male seat to be inserted, a first retaining protrusion is arranged on one side of the cavity wall of the annular plug-in cavity formed by the female seat metal terminal, and the male seat metal terminal is provided with a first card groove which cooperates with the first retaining protrusion.

2. A high current board-to-board electrical connector as claimed in claim 1, characterized in that: The male socket of the electrical connector also includes a male socket protective armor embedded in the end of the male socket plastic body, and the socket protective armor includes a first embedded piece covering the upper surface of the two ends of the male socket plastic body, a second embedded piece extending downward from the front and rear sides of the first embedded piece and attached to the front and rear sides of the male socket plastic body, and a third embedded piece bent downwardly from the left or right side of the first embedded piece.

3. A high current board-to-board electrical connector as claimed in claim 2, characterized in that: The middle part of the second embedding piece extends and is embedded in the male seat plastic body, and the bottom is provided with a first welding part that is bent and extends horizontally outward and extends from the front and rear surfaces of the male seat plastic body; the third embedding piece is provided with a second slot, and the bottom of the third embedding piece extends and is embedded in the male seat plastic body, and the end of the bottom is provided with a second welding part that is bent and extends horizontally outward and extends from the left and right surfaces of the male seat plastic body.

4. A high current board-to-board electrical connector as claimed in claim 1, characterized in that: The male socket metal terminal includes a fourth embedding piece covering the inner side of the male socket plastic body, a first connecting piece bent upward from the fourth embedding piece and covering the upper surface of the male socket plastic body, and a fifth embedding piece bent downward and covering the outer side of the male socket plastic body; the fifth embedding piece is provided with the first card groove, the middle part of the fifth embedding piece extends and is embedded in the male socket plastic body, and the bottom end is provided with a third welding part that is bent and extends horizontally outward and extends out of the front and rear surfaces of the male socket plastic body.

5. A high current board-to-board electrical connector as claimed in claim 4, characterized in that: A plurality of accommodating grooves for accommodating the female socket metal terminals are arranged along the length direction on both sides of the island, and a plug-in groove matching with the island of the female socket of the electrical connector is formed in the plastic body of the male socket.

6. A high current board-to-board electrical connector as claimed in claim 3, characterized in that: The electrical connector socket also includes a socket protective armor embedded in the end of the socket plastic body, and the socket protective armors at both ends include a first socket protective armor and a second socket protective armor that are symmetrically arranged in structure.

7. A high current board-to-board electrical connector as claimed in claim 6, characterized in that: The first protective armor of the mother seat and the second protective armor of the mother seat both include a sixth embedded piece covering the upper surface and the inner side of the plastic body of the mother seat and in contact with the third embedded piece, a seventh embedded piece bent downward from the sixth embedded piece and embedded in the end of the plastic body of the mother seat, a second connecting piece bent downward from the sixth embedded piece and extending into the annular plug-in cavity, and an eighth embedded piece horizontally bent from the seventh embedded piece to be embedded in the side of the plastic body of the mother seat.

8. A high current board-to-board electrical connector as claimed in claim 7, characterized in that: The second connecting piece is provided with a first contact arm extending upward along the length direction and accommodated at one end of the island, and a second contact arm extending upward along the width direction and in contact and conduction with the second embedded piece; the sixth embedded piece is provided with a second stop protrusion extending into the second slot; the bottom of the seventh embedded piece is provided with a fourth welding portion that is bent and extends horizontally outward and extends out of the left and right surfaces of the plastic body of the mother seat; the upper end of the eighth embedded piece is covered on the upper surface of the plastic body of the mother seat, and the lower end is provided with a fifth welding portion that is bent and extends horizontally outward and extends out of the front and rear surfaces of the plastic body of the mother seat.

9. A high current board-to-board electrical connector as claimed in claim 5, characterized in that: The female socket metal terminal includes a ninth embedded piece covering the inner side of the female socket plastic body and in contact with the fifth embedded piece, a third connecting piece bent and extended horizontally from the ninth embedded piece and constituting the cavity wall of the annular plug-in cavity, a third contact arm bent upward from the third connecting piece and extended into the accommodating groove and in contact with the fourth embedded piece, a fourth connecting piece bent upward from the ninth embedded piece and covering the upper surface of the female socket plastic body, and a tenth embedded piece bent downward from the ninth embedded piece and extended and embedded in the female socket plastic body.

10. A high current board-to-board electrical connector as claimed in claim 9, characterized in that: The ninth embedding piece is provided with the first stop-retraction protrusion; the bottom of the tenth embedding piece is provided with a sixth welding portion which is bent and horizontally extends outward and extends out of the front and rear surfaces of the female base plastic body.

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