CN107579380B

CN107579380B - Socket connector

Info

Publication number: CN107579380B
Application number: CN201710736845.0A
Authority: CN
Inventors: 谢永涛; 茆玉龙; 胡兵波
Original assignee: Smart Chip Microelectronic Co ltd
Current assignee: Smart Chip Microelectronic Co ltd
Priority date: 2017-08-24
Filing date: 2017-08-24
Publication date: 2023-03-10
Anticipated expiration: 2037-08-24
Also published as: CN107579380A

Abstract

The invention provides a socket connector, which comprises a terminal seat, two rows of conductive terminals arranged in the terminal seat, and a metal shielding sheet arranged between the two rows of conductive terminals along the height direction, wherein the terminal seat comprises a base part positioned at the rear side, a tongue plate part positioned at the front side, and a middle part positioned between the base part and the tongue plate part, the terminal seat also comprises a first body and a second body which are respectively used for fixing the two rows of conductive terminals, the metal shielding sheet and one row of conductive terminals are embedded and formed in the second body after being stacked at intervals along the height direction, the other row of conductive terminals are embedded and formed in the first body, and the first body and the second body are stacked along the height direction to form the terminal seat. The socket connector is convenient in manufacturing process and assembly.

Description

Socket connector

Technical Field

The present invention relates to a socket connector, and more particularly, to a socket connector capable of transmitting data at a high speed.

Background

A Universal Serial Bus (USB) connector is the most common connection interface for calculators at present, and a USB connector is a plug-and-play external Bus, which can be used to connect various peripheral devices, including speakers, telephones, joysticks, printers, scanners, cameras, and the like. With the popularization of USB connectors, USB connectors are widely used in the field of charging and data transmission.

With the development of the electronic industry, the existing USB2.0 receptacle connector needs to be inserted into the front and back sides, and the transmission rate is not high. In order to make the USB socket connector capable of being inserted into the front and back sides, it is a common practice to add a set of corresponding conductive terminals on the lower surface of the mating tongue plate of the USB socket connector. In order to increase the transmission rate of the USB socket connector, it is common practice to increase the number of conductive terminals. Such a method may cause a series of problems, such as poor strength of the socket connector and easy damage after multiple plugging; the conductive terminal is inconvenient to form and assemble with the insulating body and the butt tongue plate of the socket connector; the upper and lower conductive terminals will interfere with each other to affect the transmission quality of electric signals.

The socket connector has the advantages that the front side and the back side can be inserted for use, the assembly is convenient, the structure is strong, the electric signal transmission quality is high, and the use of a user can be facilitated. The USB Type-C connector is a new generation product of the USB 3.0 connector, the plug interface no longer has directionality, namely the plug connector can be inserted into the socket connector in two directions, and the data transmission speed of 10Gbit/s is supported. The USB Type-C connector comprises a plastic seat body, an upper row of conductive terminals and a lower row of conductive terminals which are arranged on the plastic seat body, and a shielding sheet clamped between the upper row of conductive terminals and the lower row of conductive terminals. The plastic seat body comprises an upper body, a lower body and an insulation body which is injection molded outside the upper body and the lower body, and the upper body and the lower body are respectively injection molded outside the two rows of conductive terminals, so that the socket connector can be manufactured only by three times of injection molding.

Accordingly, there is a need for an improved receptacle connector that overcomes the above-mentioned problems.

Disclosure of Invention

The invention aims to provide a socket connector which is simple to manufacture.

In order to achieve the above object, the present invention provides a socket connector, which includes a terminal block, two rows of conductive terminals disposed in the terminal block, and a metal shielding plate disposed between the two rows of conductive terminals along a height direction, wherein the terminal block includes a base portion located at a rear side, a tongue portion located at a front side, and a middle portion located between the base portion and the tongue portion, the terminal block further includes a first body and a second body for respectively fixing the two rows of conductive terminals, the metal shielding plate and one row of the conductive terminals are stacked at intervals along the height direction and then embedded and formed in the second body, the other row of the conductive terminals are embedded and formed in the first body, the first body and the second body are stacked along the height direction to form the terminal block, the second body is formed with a plurality of through holes penetrating along the height direction, a pre-breaking portion for connecting two adjacent conductive terminals in one row of the conductive terminals is provided between the two adjacent conductive terminals, the through holes and the pre-breaking portion are disposed corresponding to cut the corresponding pre-breaking portion through the through holes, so that the conductive terminals in one row of the conductive terminals are independent from each other.

As a further improvement of the present invention, the tongue plate portion is a front portion of the second body, and the base portion and the intermediate portion are formed by combining the first body and the second body.

As a further improvement of the present invention, the first body has a first rear side portion located on a rear side thereof to form part of the base portion and a first joint portion located on a front side thereof, and the second body has a front side portion located on a front side to form the tongue portion, a second rear side portion located on a rear side to form part of the base portion, and a second joint portion located between the front side portion and the second rear side portion.

As a further improvement of the present invention, the front side portion of the second body is located in front of the first joining portion of the first body, and the first and second joining portions are stacked in the height direction to form the intermediate portion.

As a further improvement of the present invention, the first rear side portion and the second rear side portion are respectively provided at the rear ends thereof with a plurality of partitions arranged at intervals in the transverse direction and accommodating grooves located between adjacent partitions, the partition at the rear side of the first body is inserted into the corresponding accommodating groove at the rear side of the second body, and the partition at the rear side of the second body is inserted into the corresponding accommodating groove at the rear side of the first body, so that the partitions of the first body and the partitions of the second body are arranged in a staggered manner.

As a further improvement of the present invention, the second rear side portion and the second combining portion together form a recessed area recessed downward, the second rear side portion further has a pair of protruding pillars located in the recessed area and protruding upward, the first rear side portion has a pair of positioning holes formed by penetrating the first rear side portion in the height direction, the first combining portion is received and positioned in the front of the recessed area, and the protruding pillars are inserted into the corresponding positioning holes.

As a further improvement of the present invention, each conductive terminal in the row of conductive terminals includes an inclined portion inclined outward from a rear end of the abutting portion thereof and a straight portion extending backward from a rear end of the inclined portion, the straight portion extends in a front-rear direction, and a part of the pre-breaking portion is connected to the inclined portion.

As a further improvement of the present invention, the terminal head of the front end of one row of conductive terminals is embedded in the second body, and does not protrude out of the front end surface of the second body.

As a further improvement of the present invention, the metallic shielding sheet includes a main body portion, a pair of locking portions located on both sides in the lateral direction of the main body portion and projecting outward, and a pair of connecting portions located on the front sides of the corresponding locking portions, the connecting portions being exposed to the front end face of the second body to be connected to the shielding sheet material tape.

As a further improvement of the present invention, a rear end surface of the metal shielding plate is located on a front side of the base portion of the terminal block.

The invention has the beneficial effects that: the terminal seat of the socket connector is assembled by the first body and the second body, and the metal shielding sheet is embedded and molded in the second body after being stacked with the conductive terminal in the row at intervals, so that the whole terminal seat can be formed only by assembling the first body and the second body, and the manufacture procedure and the assembly are convenient.

Drawings

FIG. 1 is a perspective view of a receptacle connector according to a preferred embodiment of the present invention;

FIG. 2 is a view of the receptacle connector of FIG. 1 from another perspective;

FIG. 3 is a perspective assembled view of the receptacle connector of FIG. 1 with the shield shell removed;

fig. 4 to 5 are partially exploded views of the receptacle connector shown in fig. 3;

fig. 6 is a further exploded view of the receptacle connector of fig. 4;

fig. 7 is a perspective assembly view of the conductive terminals and the metal shield plate in the receptacle connector shown in fig. 6;

figure 8 is a perspective view of the second terminal of figure 7;

figure 9 is a perspective view of the second terminal assembly of figure 4;

figure 10 is a view of the second terminal assembly of figure 9 from another perspective;

fig. 11 is a perspective view of a metal shield blade in the receptacle connector of fig. 6;

fig. 12 is a schematic cross-sectional view of the receptacle connector shown in fig. 3.

Detailed Description

The present invention will be described in detail below with reference to embodiments shown in the drawings. These embodiments are not intended to limit the present invention, and structural, methodological, or functional changes in accordance with the embodiments are within the scope of the present invention.

Fig. 1 to 12 show a socket connector 100 according to a preferred embodiment of the present invention. The socket connector 100 of the present invention is mounted on a circuit board (not shown), and includes a terminal block 1, two rows of conductive terminals 2 disposed in the terminal block 1, a metal shielding plate 3 disposed between the two rows of conductive terminals 2, and a shielding shell 4 covering the periphery of the terminal block 1. The two rows of conductive terminals 2 include a plurality of first terminals 21 disposed in one row and a plurality of second terminals 22 disposed in the other row. The metallic shield plate 3 is generally made of a metallic material and has conductivity.

Referring to fig. 3 to 12, the terminal block 1 is integrally formed with a base 101 located on the rear side, a tongue portion 102 located on the front side, and an intermediate portion 103 located between the base 101 and the tongue portion 102. The tongue plate portion 102 has two surfaces oppositely arranged along the height direction, and two rows of conductive terminals 2 are respectively arranged on the two surfaces of the tongue plate portion 102. In the present embodiment, the terminal base 1 further includes a first body 11 for fixing the first terminal 21 and a second body 12 for fixing the second terminal 22.

Referring to fig. 3 to 6, the first body 11 and the second body 12 are respectively injection-molded around the first terminal 21 and the second terminal 22 to form a first terminal assembly and a second terminal assembly, respectively. In the present embodiment, the metal shielding plate 3 and the row of the second terminals 22 are embedded and molded in the second body 12 after being stacked at intervals in the height direction, the tongue plate portion 102 is the front portion of the second body 12, and the base portion 101 and the middle portion 103 are formed by combining the first body 11 and the second body 12. In other embodiments, the metal shielding plate 3 may be embedded and molded in the first body 11 together with the first terminal 21, and the tongue portion 102 is a front portion of the first body 11.

The first body 11 has a first rear side portion 112 at a rear side thereof to form a part of the base 101 and a first coupling portion 113 at a front side thereof. The second body 12 has a front side portion 121 located on the front side to form the tongue plate portion 102, a second rear side portion 122 located on the rear side to form part of the base portion 101, and a second joint portion 123 located between the front side portion 121 and the second rear side portion 122. The front side 121 of the second body 12 is located in front of the first combining portion 113 of the first body 11 to independently constitute the tongue portion 102 of the terminal block 1. The first and

second coupling portions

113 and 123 of the first and

second bodies

11 and 12 are stacked in the height direction to form the intermediate portion 103.

The first coupling portion 113 of the first body 11 has a width in the transverse direction smaller than that of the first rear portion 112 thereof, and the front portion 121 and the second coupling portion 123 of the second body 12 each have a width in the transverse direction smaller than that of the second rear portion 122 thereof. A plurality of process holes 1212 are formed through the front side portion 121 (i.e., the tongue plate portion 102) of the second body 12 along the height direction, and two sides of each second terminal 22 are respectively provided with one process hole 1212, so as to effectively position the second terminal 22 during the injection molding.

The first rear side portion 112 and the second rear side portion 122 are respectively provided at the rear ends thereof with a plurality of

partitions

1123, 1223 arranged at intervals along the transverse direction and accommodating

grooves

1124, 1224 located between

adjacent partitions

1123, 1223, and the partitions 1123 of the first rear side portion 112 are formed by protruding downwards from the bottom of the rear end thereof, so that the first body 11 is L-shaped as a whole when viewed from the side. The partition 1123 at the rear side of the first body 11 is inserted downwards into the corresponding receiving groove 1224 at the rear side of the second body 12, the partition 1223 at the rear side of the second body 12 is inserted upwards into the corresponding receiving groove 1124 at the rear side of the first body 11, and the partition 1123 of the first body 11 and the partition 1223 of the second body 12 are arranged in a staggered manner to form a cross positioning structure.

The front side of the first rear side portion 112 is recessed backwards to form a containing groove 1125 with an opening facing forwards and upwards, the first rear side portion 112 further has a pair of matching holes 1126 recessed downwards from the top surface thereof and a pair of positioning holes 1127 formed by penetrating the matching holes in the height direction, the matching holes 1126 are positioned on two sides of the containing groove 1125 in the transverse direction, and the positioning holes 1127 are positioned on the front side of the corresponding matching holes 1126.

The second rear portion 122 and the second combining portion 123 together form a recessed area 124 recessed downward, the second rear portion 122 further has a pair of protruding columns 1221 protruding upward and located in the recessed area 124, when the first and

second bodies

11 and 12 are assembled with each other, the first combining portion 113 is received and located in the front of the recessed area 124, and the protruding columns 1221 are inserted upward into the corresponding locating holes 1127.

The second body 12 has a plurality of through holes 125 formed therethrough along the height direction, in this embodiment, four through holes 125 are disposed on the second combining portion 123, when viewed from the top, two through holes 125 in the middle extend along an inclined direction forming a certain angle with the transverse direction, and two through holes 125 at two sides extend along the transverse direction. The second rear side portion 122 is provided with one through hole 125, and the through hole 125 is located at a middle position of the second rear side portion 122 in the transverse direction.

The conductive terminals 2 include two rows of the first terminals 21 and the second terminals 22 along the height direction, and the first terminals 21 and the second terminals 22 are arranged correspondingly and reversely and are all the same as the conductive terminals in the standard USB Type C socket connector.

Each of the first terminal 21 and the second terminal 22 is provided with a pair of ground terminals g located on both sides of the first terminal 21 or the second terminal 22, a pair of power terminals p located on the inner side of the adjacent ground terminal g, and four signal terminals located between the pair of power terminals p. The four signal terminals comprise a CC terminal, a D + terminal, a D-terminal and an SBU terminal which are sequentially arranged; wherein the D + terminal and the D-terminal are mainly used for transmitting USB2.0 signals.

Each of the first terminals 21 and the second terminals 22 has a fixing portion 23 fixed in the first body 11 or the second body 12, a butting portion 24 extending forward from the fixing portion 23 and exposed outside the front portion 121 of the second body 12, and a solder tail 25 extending out of the terminal holder 1. The solder tails 25 of the first terminals 21 are connected to a first terminal tape (not shown), the solder tails 25 of the second terminals 22 are connected to a second terminal tape (not shown), and the rear ends of the solder tails 25 are tape connecting portions. In the present embodiment, the solder tails 25 and the butting portions 24 are arranged in parallel, and the solder tails 25 of the first terminals 21 and the second terminals 22 are located in the same row (see fig. 2) and are soldered to the circuit board by surface soldering.

In this embodiment, the head of the second terminal 22 is not connected to the second terminal strip, and only the solder tail 25 is connected to the second terminal strip, however, a pre-breaking portion 26 is disposed between two adjacent second terminals 22, and the pre-breaking portion 26 is located in the middle area of the second terminal 22 and is irregularly arranged in a front-back non-aligned manner, so as to ensure the processing accuracy of the second terminal 22 and facilitate the embedding and forming of the second terminal 22 in the second body 12. In the present embodiment, the pre-breaking portion 26 between the ground terminal g and the power terminal p and the pre-breaking portion 26 between the power terminal p and the CC terminal (or the SBU terminal) are connected in a crossing manner, the pre-breaking portion 26 between one of the power terminals p and the CC terminal and the pre-breaking portion 26 between the CC terminal and the D + terminal are connected in a crossing manner, the pre-breaking portion 26 between the other one of the power terminals p and the SBU terminal and the pre-breaking portion 26 between the SBU terminal and the D-terminal are connected in a crossing manner, and the pre-breaking portion 26 between the D + terminal and the D-terminal is located at the rear side of the remaining pre-breaking portions 26.

In addition, the fixing portion 23 of each of the second terminals 22 includes an inclined portion 231 inclined outward from the rear end of the mating portion 24 and a straight portion 232 extending backward from the rear end of the inclined portion 231, the straight portion 232 extends in the front-rear direction, and the inclined portion 231 is provided so that the straight portion 232 is parallel to but not aligned with the mating portion 24. The pre-breaking portions 26 of the other terminals are connected to the adjacent two inclined portions 231, except that the pre-breaking portion 26 between the D + terminal and the D-terminal is connected to the adjacent two straight portions 232.

After the second terminal 22 is molded in the second body 12, a terminal head portion located at the front end of the second terminal 22 is embedded in the second body 12, and does not protrude out of the front end surface of the terminal block 1. The pre-breaking portion 26 is disposed corresponding to the through holes 125, wherein two through holes 125 located in the middle (or inclined) of the second combining portion 123 are in a one-to-two relationship with the pre-breaking portion 26, and two through holes 125 located on two sides of the second combining portion 123 are in a one-to-one relationship with the pre-breaking portion 26. The through-hole 125 located at the middle position in the lateral direction of the second rear side portion 122 corresponds to the precut portion 26 between the D + terminal and the D-terminal, and the corresponding precut portion 26 is cut through the through-hole 125 so that the second terminals 22 are independent from each other.

The metal shielding plate 3 and the second terminal 22 are injection molded in the second body 12, and the contour of the metal shielding plate 3 is approximately designed corresponding to the shape of the opposite side surface of the second body 12 and is located between the first terminal 21 and the second terminal 22 along the height direction, so as to effectively isolate the first terminal 21 and the second terminal 22 and prevent the interference between the two rows of conductive terminals. In the present embodiment, the metal shielding plate 3 and the conductive terminal 2 are made of different materials, and the material of the metal shielding plate 3 is harder than that of the conductive terminal 2, for example, the metal shielding plate 3 may be made of an alloy material and the conductive terminal 2 is made of a copper material.

The metal shielding plate 3 is a horizontally disposed plate-shaped structure, and includes a U-shaped main body 31, a pair of locking portions 32 located on two sides of the main body 31 in the transverse direction and protruding outward, and a pair of connecting portions 33 located on the front sides of the corresponding locking portions 32, where the metal shielding plate 3 is connected to a shielding plate material tape (not shown) through the connecting portions 33 on the front side of the metal shielding plate 3, that is, the shielding plate material tape connected to the metal shielding plate 3 is located on the front side of the terminal base 1.

Main part 31 of metallic shield piece 3 is equipped with along direction of height with its breach 311 and a plurality of perforation 312 that runs through, breach 311 extends and is located along the transverse direction main part 31 middle part position by the back, perforation 312 is located breach 311 is along the ascending both sides of transverse direction, in this embodiment, the both sides of metallic shield piece 3 respectively are equipped with a pair of perforation 312, and the homonymy is a pair of perforation 312 is arranged along the fore-and-aft direction.

The notch 311 is defined by a pair of side walls 3112 and a transverse wall 3113 connected to the side walls 3112, the side walls 3112 extend in the front-rear direction, and the pair of side walls 3112 are located outside the power terminals p adjacent to the side walls 3112 in the transverse direction.

In the insert-embedding molding process, the metal shielding sheet 3 and the second terminals 22 are inserted into the notches 311 and the through holes 312 by a thimble (not shown) to clamp the metal shielding sheet 3 and the second terminals 22 up and down, so as to ensure the position of the metal shielding sheet 3 and the coplanarity of the second terminals 22. Meanwhile, the molten plastic material for forming the second body 12 enters the notch 311 and the through hole 312 to enhance the bonding strength between the metal shielding plate 3 and the second body 12.

When the metal shielding plate 3 is formed in the second body 12, the locking portion 32 is wrapped in the second body 12 of the terminal base 1 and does not protrude outward from the terminal base 1, and when the metal shielding plate 3 is butted with the butting connector, the parts of the plastic second body 12 corresponding to the locking portion 32 are locked with the butting connector, so that the metal shielding plate 3 made of the metal material is prevented from directly rubbing with the butting connector in a sliding manner to cause abrasion to the butting connector, and the butting connector is smoothly butted. The connecting portion 33 is exposed out of the front end surface of the second body 12 (i.e. the front end surface of the terminal block 1), the main body portion 31 is covered in the second body 12, and the rear end surface of the metallic shielding plate 3 is embedded in the second combining portion 123 of the second body 12, that is, the rear end surface of the metallic shielding plate 3 is located at the front side of the second rear portion 122 (or the front side of the base portion 101 of the terminal block 1), in other words, the metallic shielding plate 3 does not have any structure protruding backward out of the second body 12, but has a short structure with only the front end protruding out of the front end surface of the second body 12, so that the metallic shielding plate 3 does not have the structural features of the conventional solder pins for soldering with the circuit board, and the subsequent assembly and soldering processes are omitted.

Referring to fig. 1 and 2, the shielding shell 4 is disposed in an elliptical tube shape and covers the periphery of the terminal block 1. The shielding shell 4 has a pair of position-limiting pieces 41 bent and inclined from the top wall thereof and extending downward, and at least one convex structure 42 protruding from the top wall and/or the bottom wall thereof into the tubular space thereof, wherein the position-limiting pieces 41 extend downward into the corresponding matching holes 1126, and the convex structure 42 protrudes into the corresponding receiving groove 1125. The shielding shell 4 has mounting feet 43 extending downward on both sides thereof for securing the receptacle connector 100 to a circuit board.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a socket connector, its includes the terminal seat, becomes two rows and sets up the conductive terminal in the terminal seat and sets up the metallic shield piece between two rows of conductive terminals along the direction of height, the terminal seat is including the basal portion that is located the rear side, the hyoplastron portion that is located the front side and the intermediate part that is located between basal portion and the hyoplastron portion, the terminal seat still includes the first, the second body of fixing two rows of conductive terminals respectively, its characterized in that: the metal shielding piece is one row with wherein the conductive terminal piles up the back along the direction of height interval inlay the buried shaping in the second is originally internal, another row of conductive terminal inlay the buried shaping in first is originally internal, first body and second body pile up in order to form along the direction of height the terminal seat, the second body runs through along the direction of height and is formed with a plurality of through-holes, have the part of precutting that will link to each other between two adjacent conductive terminals in one of them row of conductive terminal, the through-hole with the part of precutting corresponds the setting in advance, so that pass through the through-hole cuts the messenger to corresponding precutting portion each conductive terminal in one of them row of conductive terminal is independent each other.

2. The receptacle connector of claim 1, wherein: the tongue portion is a front portion of the second body, and the base portion and the intermediate portion are formed by combining the first body and the second body.

3. The receptacle connector of claim 2, wherein: the first body has a first rear side portion located at a rear side thereof to form a part of the base portion and a first joint portion located at a front side thereof, and the second body has a front side portion located at a front side to form the tongue portion, a second rear side portion located at a rear side to form a part of the base portion, and a second joint portion located between the front side portion and the second rear side portion.

4. The receptacle connector of claim 3, wherein: the front side part of the second body is positioned in front of the first combining part of the first body, and the first combining part and the second combining part are stacked in the height direction to form the middle part.

5. The receptacle connector of claim 3, wherein: the first rear side part and the second rear side part are respectively provided with a plurality of barriers arranged at intervals along the transverse direction and accommodating grooves positioned between adjacent barriers at the rear ends thereof, the barrier at the rear side of the first body is inserted into the corresponding accommodating groove at the rear side of the second body, and the barrier at the rear side of the second body is inserted into the corresponding accommodating groove at the rear side of the first body, so that the barriers of the first body and the barriers of the second body are arranged in a staggered manner.

6. The receptacle connector of claim 5, wherein: the second rear side part and the second combining part jointly form a sunken area which is sunken downwards, the second rear side part is also provided with a pair of protruding columns which are positioned in the sunken area and protrude upwards, the first rear side part is provided with a pair of positioning holes which penetrate through the first rear side part along the height direction, the first combining part is accommodated and positioned in the front part of the sunken area, and the protruding columns are inserted into the corresponding positioning holes.

7. The receptacle connector of claim 1, wherein: each conductive terminal in one row of conductive terminal includes the skew portion that sets up from the rear end of its butt joint portion outside skew and the straight portion that extends backward from the rear end of skew portion, straight portion extends along the fore-and-aft direction, and some the pre-break portion with the skew portion links to each other.

8. The receptacle connector of claim 1, wherein: the terminal head part of the front end of one row of conductive terminals is embedded in the second body and does not protrude out of the front end face of the second body.

9. The receptacle connector of claim 3, wherein: the metal shielding sheet comprises a main body part, a pair of locking parts which are positioned at two sides of the main body part in the transverse direction and protrude outwards, and a pair of connecting parts which are positioned at the front sides of the corresponding locking parts, wherein the connecting parts are exposed at the front end surface of the second body so as to be connected with the shielding sheet material belt.

10. The receptacle connector of claim 9, wherein: the rear end face of the metal shielding sheet is positioned on the front side of the base of the terminal block.