TWI398996B - Waterproof connector and relay connector - Google Patents

Description

Waterproof connector and relay connector

The invention relates to a waterproof connection cable connector and a relay connector.

As shown in Fig. 7(a), the conventional waterproof connector peels off the end skins 183a and 193a of the cables 183 and 193, and connects the terminals 180 and 190 to the cable core. First, the polyethylene-based synthetic rubber is used. 121b and 131b are integrally molded by injecting the core portions 183b and 193b of the cable, and then integrally molded with the synthetic rubbers 121a and 131a to ensure adhesion to the cable skin.

This is because the adhesion between the polyethylene cable skin and the synthetic rubber is not good. Therefore, if the polyethylene-based synthetic rubber is not filled, the waterproofness of the casings 121 and 131 cannot be ensured, and the structure is complicated and manufactured. The reason for the increase in cost, and if the housing is not integrally molded at the end of the cable in advance, it is not possible to connect the cable length.

As shown in Fig. 7(b), the conventional structure is to bond the mounting tube portion 170 with an adhesive at the interface between the cable 100 and the housing 141. In this case, the length of the cable is also determined in advance. Bonded at the end.

In the technique disclosed in Japanese Laid-Open Patent Publication No. 2001-210426, a conical trapezoidal elastic sleeve member through which a cable is inserted is attached to a conical insertion opening of a casing, and a cover having a nut is screwed from the outside to utilize The conical surface is used to clamp the cable, and the tightness of the elastic sleeve member and the cable is changed by the screwing amount of the cover body, but proper clamping management is difficult and it is difficult to uniformly cover The ground is tightly attached to the cable throughout the week.

[Patent Document 1] Japanese Special Publication No. 2001-210426

The present invention has been made in view of the above technical problems, and an object thereof is to provide a connector having high water repellency that can be easily attached to a terminal end of a cable, and a waterproof relay connector using the connector.

The main technology of the present invention is a waterproof connector for connecting a cable, and the connector is provided with a housing in which a terminal connected to the front end of the cable is inserted, a waterproof tube covering the outer circumference of the housing and the outer circumference of the cable, and The outer peripheral side clamps the detachable clamping housing of the waterproof tube.

By adopting such a configuration, the terminal to which the front end of the cable is connected is inserted and mounted to the inner side of the casing, and then the waterproof pipe is inserted and installed to cover the outer periphery of the casing and the outer circumference of the cable to sandwich the waterproof from the outside. The outer circumference of the tube is mounted to the clamping housing.

In the present invention, the so-called detachable clamping housing is such that the outer casing is opened in a direction opposite to the axial direction of the waterproof tube (the long axis direction of the cable), and is mounted from the outer peripheral side of the waterproof tube to form a split-shaped clamping housing. When closed, the outer circumference of the waterproof tube can be clamped.

In the case where the clamping housing is in the open state, the upper and lower housings are completely It is also possible to separate into two, and to connect one of the upper and lower outer casings, and to form a split shape that is bent at the joint portion.

The second invention shows an example of the configuration of the clamp housing, the male housing and the female housing being disengageable along the long axis direction of the cable, and having a circle having a smaller inner circumference than the semicircle at the bottom of the male housing and the female housing The arc rib portion has a clamping protrusion that rises from the arc rib along the outer circumference of the waterproof tube, and the female housing has a clip that rises from the arc rib along the outer circumference of the waterproof tube and is inclined toward the center side. The tight guiding surface, when the male outer casing and the female outer casing are attached to the outer circumference of the waterproof pipe, the clamping tab is inclinedly guided toward the center side along the clamping guiding surface, and the waterproof pipe is clamped to the inner side.

The male outer casing and the female outer casing form a clamping outer casing, and the inner circumferential surface of the male outer casing and the female outer casing are provided with smaller semicircular arc ribs, and the male outer casing has clamping tabs, and the female outer casing has a central side Since the male outer casing and the female outer casing are attached, when the waterproof pipe is sandwiched from the outer circumferential side, for example, the circular ribs of the inner circumferential surface of the male outer casing and the female outer casing are pressed from the upper and lower sides. The tube, and the clamping tab provided on the male housing, moves toward the center side along the clamping guide surface of the male housing, and also presses the waterproof tube from the side.

According to a third aspect of the invention, in the waterproof connector of the second aspect of the invention, the male housing and the female housing have cable clamping claws.

According to the second aspect of the invention, when the waterproof tube is sandwiched between the male housing and the female housing and attached to the outer circumference of the waterproof tube, the clamping tab of the male housing engages with the clamping guide surface of the female housing to clamp the waterproof tube. According to the third aspect of the invention, the following structure is formed by providing the clamping ribs in the male outer casing and the female outer casing.

By mounting the waterproof tube on the outer circumference of the casing and the outer circumference of the cable, In addition, in order to make the tightness of the waterproof tube more reliable, in the outer peripheral portion of the waterproof pipe, it is clamped from the outer peripheral side: a portion located on the outer periphery of the casing, and a cable located at the outer periphery of the casing The two portions of the outer peripheral portion are preferred.

In this case, the clamp structure of the second aspect of the invention may be provided at two locations of the outer peripheral portion of the casing and the outer peripheral portion of the cable, and only the clamp structure of the second invention may be provided in the outer peripheral portion of the cable. The outer peripheral portion of the waterproof tube is provided with an auxiliary rib portion in an outer peripheral portion of the waterproof tube corresponding to the outer peripheral portion of the casing having a larger diameter than the outer circumference of the cable.

According to the fourth aspect of the invention, the male housing and the female housing are provided with cable gripping claws for preventing the housing from being displaced from the cable.

The waterproof connector of the present invention can utilize various cable connectors for the purpose of waterproofing.

If the connector of the plug terminal and the connector of the socket terminal are paired, a waterproof relay connector can be used.

In the present invention, at the interface between the casing of the cable terminal and the cable, the outer circumference of the casing and the outer circumference of the cable are attached to the outer casing to install the waterproof pipe, and the clamping casing for clamping the outer peripheral portion of the waterproof pipe is made to be disengageable, so that waterproofing can be achieved. The connector is simply attached to the front end of the cable.

Therefore, it is not necessary to integrally mold or bond the connector to the end of the cable as in the prior art, and now it is only necessary to cut the cable to the required length and then install the waterproof connector.

Thereby, no waste is caused in the length adjustment of the cable and the efficiency of the wiring work is also improved.

The male outer casing and the female outer casing constitute a clamping outer casing. When the male outer casing and the female outer casing are fitted to sandwich the waterproof pipe, only the inner circumferential surface of the male outer casing and the inner circumferential surface of the female outer casing are clipped by the circular arc ribs. The clamping of the opposite part of the tight casing may not be sufficient, and the clamping tab is provided on the male housing, and the clamping projection is inclined toward the center side when the female housing is provided with the clamping guide surface inclined toward the center side. The part presses the split portion, so the clamping force can cover the entire circumference of the waterproof tube, and the waterproofness is improved.

Hereinafter, an example in which the waterproof connector of the present invention is applied to the relay connector 10 will be described based on the drawings.

Fig. 1(a) shows a longitudinal section of the state before the socket connector 20 and the plug connector 30 are fitted, and Fig. 2 shows a longitudinal section of the state after the fitting.

The relay connector 10 includes a socket connector 20 and a plug connector 30, and has a housing 21, 31, a waterproof tube 70, and a clamp housing 40, respectively.

Fig. 1(b) shows a state in which the clamp housing 40 is removed.

Fig. 1(a) shows the cable 83 and the waterproof tube 70 on the front side in order to show the inner side fitting portion of the female outer casing 50 and the male outer casing 60.

As shown in FIG. 2, the relay connector 10 fits the receptacle connector 20 and the plug connector 30 to each other, and the terminals of the housings 21, 31 are inserted into the holes 23, The terminals 80, 90 in 33 are electrically connected to each other.

The terminal insertion holes 23 and 33 are provided to penetrate the socket housing 21 and the plug housing 31, respectively.

As shown in Fig. 1, the cable-side opening portions of the terminal insertion holes 23 and 33 are provided with tube mounting portions 24 and 34 that project the housings 21 and 31 into a tubular shape.

The terminals 80 and 90 attached to the ends of the cables 83 and 93 are attached to the terminal insertion holes 23 and 33 from the tube mounting portions 24 and 34 side by the waterproof tube 70.

The terminals 80 and 90 are crimped and connected to the end core wires of the cables 83 and 93 by the caulking portions 82 and 93, and the warps 81 and 91 are locked to the locking phase portions 23a and 33a, and are provided to the clamp housing 40. The cable holding claws 51a, 61a hold the cables 83, 93.

The housing is provided with housing positioning recesses 27, 28 to engage with the positioning projections 58, 68 on the clamping housing side, so that the cable clamping jaws prevent offset of the clamping housing.

On the other opening side of the terminal insertion holes 23 and 33, the casings 21 and 31 are protruded into a tubular shape, and cylindrical partition walls 22 and 32 that extend the terminal insertion holes 23 and 33 are provided.

The cylindrical partition wall portion 22 of the socket housing 21 has an annular sealing member (O-ring) 26 embedded in the outer peripheral surface.

As shown in Fig. 2, the tubular partition wall portion 22 of the receptacle connector 20 can be fitted into the tubular partition wall portion 32 of the plug connector 30, and the sealing member 26 abuts against the cylindrical partition wall portion 32 of the plug connector 30. The surface is fitted in a watertight manner.

By fitting the receptacle connector 20 and the plug connector 30 to each other, the sealing member 26 is made watertight, and the terminal insertion holes 23 and 33 are communicated with each other inside, and the receptacle terminal 80 is fitted to the plug terminal 90.

The waterproof structure of the connection portion between the receptacle connector 20 and the plug connector 30 is not limited to the above-described O-ring structure as long as it can be watertightly connected.

The receptacle connector 20 and the plug connector 30 have the same configuration of the tube mounting portions 24, 34 of the housings 21, 31, the waterproof tube 70, and the clamping housing 40.

The waterproof tube 70 has rubber elasticity and is elastically connected with the stage portion 73 when the outer circumference of the casing is fitted to the outer circumference of the casing: the cylindrical tubular casing abutting portion 71 and the cable abutting portion 72 .

The inner diameter of the housing abutting portion 71 is smaller than the outer diameter of the tube mounting portions 24, 34, and when fitted to the tube mounting portions 24, 34, the inner peripheral surface thereof is elastically adhered to the tube mounting portions 24, 34 in a watertight manner. On the outer peripheral surface.

The inner diameter of the cable abutting portion 71 is equal to or slightly larger than the outer shape of the outer casings 83a, 93a of the cables 83, 93, and the cables 83, 93 to which the terminals 80, 90 are connected can easily pass.

The clamp housing 40 has a female housing 50 and a male housing 60 as shown in Fig. 1(b), and has housing fitting recesses 52, 62 and cable fitting recesses 53, 63, respectively.

The female housing 50 and the male housing 60 are partially fitted into the housing fitting recesses 52, 62 in the tube mounting portions 24, 34, and the cable fitting recesses 53, 63 are partially embedded in the cable skins 83a, 93a, as shown in Fig. 1(a). The indications can be fitted to each other.

Housing clamping ribs 52a and 62a are provided in the housing fitting recesses 52 and 62, and circular arc ribs 53a and 63a are provided in the cable fitting recesses 53 and 63.

The housing clamping ribs 52a, 62a and the circular arc ribs 53a, 63a, as shown in Fig. 1(a), are fitted to each other by the female housing 50 and the male housing 60, the housing clamping rib 52a, 62a presses the waterproof tube 70 on the tube mounting portions 24, 34 in the fitting direction, and the circular arc ribs 53a, 63a are pressed from the outer peripheral side in the fitting direction: the cable skins 83a, 93a outside the tube mounting portions 24, 34 Waterproof tube 70 on.

The fitting structure of the female housing 50 and the male housing 60 will be described later.

Fig. 5(a) is a cross-sectional view taken along line A-A of Fig. 1(a), and Fig. 5(b) is a cross-sectional view taken along line B-B of Fig. 1(b).

Fig. 5(c) is a perspective view showing a portion of the clamping tab 65 and the clamping guide surface 57.

As shown in Fig. 5(b), the arcuate ribs 53a and 63a have a rib shape having an inner circumferential surface 53b and 63b which are fitted to the outer circumferential shape of the cable skin 83a.

At both end positions of the circular arc rib portion 53a provided in the female housing 50, a clamping guide member 55 is protruded toward the fitting direction, and the clamping guide member 55 is provided with a clamping guide groove 56 in the fitting direction. A clamping guide surface 57 is formed along the fitting direction.

At the both end positions of the circular arc rib 63a provided in the male outer casing 60, the clamp protrusion 65 is formed in the fitting direction.

As shown in Fig. 5(a), when the female housing 50 and the male housing 60 are fitted to each other, the circular arc ribs 53a, 63a sandwich the outer circumferential direction to press the upper portion of the cable skin 83a of the waterproof tube 70, The waterproof tube 70 is closely attached to the cable skins 83a and 93a in a watertight manner.

At this time, the clamp projection 65 is slidably guided by the clamp guide surface 57, and is bent toward the inner side in the direction perpendicular to the fitting direction of the cable 83 in the direction of the center axis, and the front end portion 65b is fitted to the clip. The insertion recess 56a of the guide groove 56 is tightly guided.

By clamping the tab 65, the inner surface of the cable skin 83a of the waterproof tube 70 is pressed from the side portion by the inner pressing surface 65a, and the waterproof tube 70 is closely adhered to the cable skin 83a in a watertight manner.

At this time, the inner peripheral surfaces 53b and 63b of the circular arc ribs 53a and 63a are pressed against the pressing portion of the waterproof tube 70 and the pressing surface 65a of the clamping tab 65 with respect to the waterproof tube 70, as shown in Fig. 5(a). The contract is continuous in the outer circumferential direction of the cable skins 83a and 93a, and the waterproof tube 70 is uniformly and continuously adhered to the cable skin 83a in the outer circumferential direction.

Fig. 6(a) is a plan view showing a front view of the socket connector 20 and the plug connector 30 before fitting, and Fig. 6(b) is a plan view showing the appearance after fitting.

The socket connector 20 is provided with a housing locking claw 25 having a fitting direction, the housing locking claw 25 having a claw portion 25a at the front end, and the plug housing 31 is provided corresponding to the position of the housing locking claw 25. There is a housing locking claw seat 35 that is perforated in the fitting direction.

As shown in FIG. 1(b), when the socket housing 21 and the plug housing 31 are When fitting each other, the case locking claw 25 is snap-fitted to the case locking claw seat 35, and the fitting of the socket connector 20 and the plug connector 30 is fixed.

Next, the connection order of the connector and the cable and the fitting structure of the clamp housing will be described.

3 is an explanatory view showing a connection sequence of the cable 83 with respect to the receptacle connector 20, and FIG. 4 is an explanatory view showing a connection sequence of the cable 93 with respect to the plug connector 30.

For the sake of easy understanding, the third drawing is sequentially shown from the left side: an external view of the side of the receptacle connector 20, a longitudinal section of the cable direction, a cross-sectional end view corresponding to the C-C line, and a fourth figure from the right. The appearance of the side surface of the plug connector 30, the longitudinal cross-sectional view in the cable direction, and the cross-sectional end view corresponding to the D-D line are sequentially displayed.

The structure in which the mounting cable is inserted into the connector housing and the clamping housing is mounted is common to the plug connector 20 and the plug connector 30, so the case of the socket connector 20 will be described as a representative.

Fig. 3(a) shows the tube mounting in which the housing abutting portion 71 of the waterproof tube 70 is fitted to the socket connector housing (hereinafter referred to as a housing) 21 before the female housing 50 and the male housing 60 are attached. The state of the part 24.

The female housing 50 is provided with a lock arm 54 extending from the side surface of the base portion 51 toward the fitting direction side, and the lock arm 54 has a locking recess 54a on the inner side and is approximately U-shaped.

The male housing 60 is provided with an extending piece 61b that expands the side surface of the base 61 toward the fitting direction side, and a temporary fitting claw 64b is provided on the side surface of the extending piece 61b, and is interposed from the temporary fitting claw 64b toward the fitting direction. Scheduled interval On the side, a true fitting claw 64a is provided.

As shown in FIG. 3(b), the female housing 50 and the male housing 60 abut the edge portion 54b of the locking arm 54 on the fitting direction side to the true fitting claw 64a, and the locking recess of the locking arm 54 is fitted. When the 54a is engaged with the temporary fitting claw 64b of the male casing 60, the interval between the circular arc ribs 53a and 63a is opened, and the cable opening 41 between the cable holding claws 51a and 61a is opened.

In the description, the fitting state of the female housing 50 to which the cable opening 41 is opened and the male housing 60 is referred to as a temporary fitting state.

In the temporary fitting state, the female housing 50 and the male housing 60 are not detached from the housing 21, so that it is easy to take, and the cable 83 having the socket terminal 80 mounted at the end can be easily passed through the cable opening 41. It is attached to a predetermined position in the terminal insertion hole 23 as shown in Fig. 3(c).

From the temporary fitting state, the fitting of the female housing 50 and the male housing 60 is further performed. When the fitting claw 64a passes over the locking arm 54, as shown in Fig. 3(d), the locking recess 54a is engaged with the true fitting. Claw 64a.

In the description, this fitting state is referred to as a true fitting state.

In the true fitting state, the arcuate ribs 53a and 63a press the waterproof tube 70 toward the cable skin 83a from both sides in the fitting direction as shown in Fig. 5(a), and the clamping tab 65 will seal the waterproof tube 70. The waterproof tube 70 is continuously and watertightly adhered to the cable skin 83a in the outer circumferential direction from the right-angle direction side toward the cable skin 83a.

At this time, as shown in Fig. 1(a), the casing of the waterproof pipe 70 is in close contact with the portion 71, and the inner peripheral surface thereof is continuous in the outer circumferential direction by the elastic contraction force and water. Closely attached to the pipe attaching portion 24, the casing clamping ribs 52a, 62a formed in the casing fitting recesses 52, 62 press the outer peripheral surface of the casing abutting portion 71 toward the pipe attaching portion 24, The inner circumferential surface of the waterproof tube 70 is brought into close contact with the tube mounting portion 24.

Thereby, in the true fitting state, the inner peripheral surface of the waterproof tube 70 is in close contact with the casing 21 side and the cable 83 side in the outer circumferential direction, and the joint portion between the casing 21 and the cable 83 is made waterproof.

Although the application example of the waterproof connector of the present invention is described by a relay connector, it can be applied to various connectors, and in the case of a relay connector in which solar cells are connected to each other in a solar energy system, most solar energy can be used. The battery is easily connected.

10‧‧‧Relay connector

20‧‧‧ socket connector

21‧‧‧Socket housing

22‧‧‧Cylinder partition

23‧‧‧Terminal insertion hole

23a‧‧‧Clock phase

24‧‧‧ Tube Installation Department

25‧‧‧Shell card claws

25a‧‧‧ claws

26‧‧‧ Sealing member (O-ring)

30‧‧‧ plug connector

31‧‧‧ plug housing

32‧‧‧Cylinder partition

33‧‧‧Terminal insertion hole

33a‧‧‧Clock phase

34‧‧‧ Tube Installation Department

35‧‧‧Shell lock claw seat

40‧‧‧Clamping housing

41‧‧‧ cable port

50‧‧‧Female shell

51‧‧‧ base

51a‧‧‧Cable gripper

52‧‧‧ housing fitting recess

52a‧‧‧Sheet clamping ribs

53‧‧‧Cable fitting recess

53a‧‧‧Arc ribs

53b‧‧‧ inner circumference

54‧‧‧Lock arm

54a‧‧‧Lock recess

54b‧‧‧edge of the fitting direction

55‧‧‧Clamping guide member

56‧‧‧Clamping guide groove

56a‧‧‧Into the recess

57‧‧‧Clamping guide surface

60‧‧ ‧ male housing

61‧‧‧ base

61a‧‧‧Cable gripper

61b‧‧‧Extension

62‧‧‧ housing fitting recess

62a‧‧‧Sheet clamping ribs

63‧‧‧ Cable fitting recess

63a‧‧‧Arc ribs

63b‧‧‧ inner circumference

64a‧‧‧ true fitting claw

64b‧‧‧ Temporary fitting claws

65‧‧‧Clamping tabs

65a‧‧‧ Pressing surface

65b‧‧‧ front end

70‧‧‧Waterproof tube

71‧‧‧Shell close

72‧‧‧ Cable Clamping Department

73‧‧‧ Stage Department

80‧‧‧Socket terminal

81‧‧‧Socket terminal block

82‧‧‧The seaming department

83‧‧‧ cable

83a‧‧‧ cable skin

90‧‧‧ Plug terminal

91‧‧‧ Plug terminal block

92‧‧‧The Ministry of Folding

93‧‧‧ cable

93a‧‧‧ cable skin

Fig. 1 is a longitudinal sectional explanatory view showing an embodiment of a relay connector to which the waterproof connector of the present invention is applied.

Fig. 2 is an explanatory view showing a longitudinal section of a state in which the socket connector and the plug connector are fitted.

Figure 3 shows an assembly diagram of the socket connector.

Figure 4 shows an assembly diagram of the plug connector.

Fig. 5(a) shows an end view of the A-A line, (b) shows an end view of the B-B line, and (c) shows a perspective view of the clamping tab and the clamping guide surface portion.

Fig. 6(a) is a plan view showing a front view of the socket connector before being fitted to the plug connector, and Fig. 6(b) is a top plan view showing the fitting after fitting.

Figure 7 shows the waterproof construction of the interface between the housing of the conventional connector and the cable.

10‧‧‧Relay connector

20‧‧‧ socket connector

21‧‧‧Socket housing

22‧‧‧Cylinder partition

23‧‧‧Terminal insertion hole

23a‧‧‧Clock phase

24‧‧‧ Tube Installation Department

25‧‧‧Shell card claws

25a‧‧‧ claws

26‧‧‧ Sealing member (O-ring)

27‧‧‧Enclosure positioning recess

30‧‧‧ plug connector

31‧‧‧ plug housing

32‧‧‧Cylinder partition

33‧‧‧Terminal insertion hole

33a‧‧‧Clock phase

34‧‧‧ Tube Installation Department

40‧‧‧Clamping housing

50‧‧‧Female shell

51‧‧‧ base

51a‧‧‧Cable gripper

52‧‧‧ housing fitting concave section

52a‧‧‧Sheet clamping ribs

53‧‧‧Cable fitting recess

53a‧‧‧Arc ribs

53b‧‧‧ inner circumference

55‧‧‧Clamping guide member

56‧‧‧Clamping guide groove

56a‧‧‧Into the recess

57‧‧‧Clamping guide surface

58‧‧‧ positioning convex

60‧‧ ‧ male housing

61‧‧‧ base

61a‧‧‧Cable gripper

61b‧‧‧Extension

62‧‧‧ housing fitting recess

62a‧‧‧Sheet clamping ribs

63‧‧‧ Cable fitting recess

63a‧‧‧Arc ribs

63b‧‧‧ inner circumference

64a‧‧‧ true fitting claw

64b‧‧‧ Temporary fitting claws

65‧‧‧Clamping tabs

65a‧‧‧ Pressing surface

65b‧‧‧ front end

68‧‧‧ positioning convex

70‧‧‧Waterproof tube

71‧‧‧Shell close

72‧‧‧ Cable Clamping Department

73‧‧‧ Stage Department

80‧‧‧Socket terminal

81‧‧‧Socket terminal block

82‧‧‧The seaming department

83‧‧‧ cable

83a‧‧‧ cable skin

90‧‧‧ Plug terminal

91‧‧‧ Plug terminal block

92‧‧‧The Ministry of Folding

93‧‧‧ cable

93a‧‧‧ cable skin

Claims (4)

A waterproof connector, which is a waterproof connector for connecting cables, characterized in that: the connector is provided with a housing in which a terminal connected to the front end of the cable is inserted, and covers the outer circumference of the housing and the outer circumference of the cable. a tube, and a slidable clamping housing that clamps the waterproof tube from the outer peripheral side; the clamping housing has a male housing and a female housing that are disengageable along the long axis of the cable and has an inner circumference at the bottom of the male and female housings The circular rib having a smaller surface than the semicircle, the male outer casing has a clamping protrusion rising from the circular rib along the outer circumference of the waterproof tube, and the female outer casing has: rising from the circular rib along the outer circumference of the waterproof tube And the clamping guide surface inclined toward the center side, when the male housing and the female housing are mounted on the outer circumference of the waterproof tube, the clamping tab is inclined along the clamping guiding surface toward the center side, and the waterproof tube is Clamped to the inside. A waterproof connector according to claim 1, wherein the inner peripheral surface of the male housing and the female housing has a clamping rib for clamping the waterproof tube. A waterproof connector according to claim 1 or 2, wherein the male and female housings have cable gripping claws. A relay connector characterized by using a pair of waterproof connectors of claim 1, 2 or 3, wherein one of the terminals is a plug terminal and the other terminal is a socket terminal.