Abstract:
A board-to-board connector for mating with another connector has a housing and a plurality of terminals. The terminals and housing interact at a reference surface to accurately locate the terminals relative to the housing. The housing includes an elongated recess that extends parallel to a longitudinal axis of the housing and has a plurality of terminal receiving cavities spaced therealong. Each cavity includes a terminal retention wall with a reference surface on one side thereof and a terminal alignment opening extending from the cavity. Each terminals is disposed in a terminal receiving cavity. Each terminal includes a U-shaped retention portion, an L-shaped resilient contact portion extending from the U-shaped retention portion and has a contact projection thereon. A tail portion for interconnection to a circuit member is also provided. The U-shaped retention portion includes first and second spaced apart legs and a connecting portion therebetween with the U-shaped retention portion dimensioned to securely receive the terminal retention wall of the housing between the spaced apart legs. The first leg is positioned along and engages the reference surface in order to accurately position the terminal within the terminal receiving cavity, and a terminal alignment projection extends from the U-shaped retention portion and projects into the terminal alignment opening to further position and secure the terminal within the cavity.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to board-to-board connectors. 
     2. Description of the Related Art 
     Conventionally, board-to-board connectors may be used to electrically connect two parallel circuit boards together. Such board-to-board connectors are configured as a mating pair of connectors each of which are attached to and project from mutually facing surfaces of two circuit boards. 
       FIG. 6  is a cross section of one such conventional board-to-board connector. Reference numeral  301  denotes a first connector that is mounted on a first circuit board (not shown). The first connector  301  is mated and connected with a second connector (not shown) that is mounted on a second circuit board (not shown), whereby the conductive circuits on the first and second circuit boards are electrically connected to each other. The first connector  301  includes a plurality of terminals  302  that engage counterpart terminals of the second connector. 
     Each of the terminals  302  has a retention portion  308  secured to an inner surface of the housing of the first connector  301  and an intermediate portion  303  connected to the retention portion  308  and extending along an outer surface of the housing. The retention portion  308  and the intermediate portion  303  engage a portion of the housing, whereby each terminal  302  is held within the first connector  301 . A retention barb  309  is formed on the retention portion  308 . The retention barb  309  bites or skives into the housing which increases the force holding the terminal  302  within the housing. A tail portion  304  of the terminal  302  is soldered to a corresponding conductive circuit on the surface of the first circuit board. 
     A contact beam  305  is connected to the retention portion  308 , and extends in a direction away from the intermediate portion  303 . The contact beam  305  has a generally L-shape, and includes a contact projection  306  formed at its end. When the first connector  301  is mated with the second connector (not shown), the counterpart terminals of the second connector enter recess portions  307  of the first connector  301  and the contact projection  306  of each first terminal comes into contact with a contact portion of the corresponding counterpart terminal of each second connector, whereby the conductive circuits of the first and second circuit boards are electrically connected. 
     In the conventional board-to-board connector pair, each terminal  302  is fixed to the housing of the first connector  301  by means of the retention portion  308  and the intermediate portion  303 . Since the retention portion, from which the contact projection  306  extends, bites or skives into the housing, and the depth of the skiving cannot be easily controlled, the location of the contact projection  306  with respect to the housing may not be located consistently resulting in the first connector having relatively poor dimensional accuracy. More specifically, the inwardly facing surface of recess  307  is used as a reference surface or datum and the contact beam  305  and contact projection  306  are positioned relative thereto. However, since the retention barb skives into the housing along the inwardly facing surface of recess  307  and such skiving may not be consistent, the positioning of barb  308  and thus contact beam  305  and contact projection  306  may not be consistent within the housing. Thus, even if the dimensional accuracy of the contact beam  305  of the terminal  302  were high, the position of the contact beam  305  and the contact projection  306  in relation to the housing is difficult to maintain, which may result in difficulty in properly mating the first connector  301  with the second connector. 
     Furthermore, when unmating the second connector from the first connector  301 , an upward force acts on the contact projection  306 . Since this upward force creates a rotational moment on the contact beam  305 , it places a force on the retention portion  308  and the retention barb  309  which may separate the terminal from the inwardly facing surface of the corresponding recess portion  307  of the housing and cause the retention barb  309  and the terminal  302  to loosen relative to the housing. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to solve the above-mentioned problems in the conventional board-to-board connectors and to provide a reliable board-to-board connector pair in which first terminals each include a L-shaped contact portion and an inverted U-shaped retention portion integrally connected with the contact portion. The terminals are attached to a first connector housing by press-fitting them from the mating surface side. Inserting the terminals from this direction, or “top loading,” can reduce the necessary mounting area of the connector, stabilize the overall position of the terminals, and reduce the likelihood of lifting the terminals which might otherwise occur at the time of unmating. 
     To achieve the above object, the present invention provides a board-to-board connector which comprises a first connector, including a receiving recess in which first terminals are disposed, and a side wall portion adjacent to one side of the insertion recess and a second connector, adapted to be mated with the first connector, and including an insertion projection on which second terminals to come into contact with the first terminals are disposed. The insertion projection of the second connector being inserted into the receiving recess of the first connector. The side wall portion includes a first-terminal fixing hole formed on a side toward the receiving recess and extending in the insertion direction of the insertion projection, and a housing reference surface including a surface of the first-terminal fixing hole away from the receiving recess and extending in the insertion direction of the insertion projection. Each of the first terminals includes an L-shaped contact portion and an inverted-U-shaped retention portion. The L-shaped first contact portion includes a first vertical portion, disposed on one side of the receiving recess away from the side wall portion and having a first projecting portion formed thereon and a second vertical portion, disposed on the opposite side of the receiving recess toward the side wall portion and having a second projecting portion formed thereon. The retention portion includes a terminal reference surface extending in the insertion direction of the insertion projection and formed along a side edge of the second vertical portion opposite the receiving recess. The terminal reference surface contacts the housing reference surface. A first leg portion having a distal end portion is press-fit into the first-terminal fixing hole. A second leg portion extending in the insertion direction cooperates with the first leg portion grasping the side wall portion 
     Preferably, the second leg portion includes an engagement projection and the side wall portion includes an engagement portion formed on a side surface thereof opposite the receiving recess and coming into engagement with the engagement projection. The second leg portion may include a solder tail portion formed at a distal end thereof. When the insertion projection of the second connector is inserted into the receiving recess, each of the first terminals is elastically deformed and expanded to grip the insertion projection between the first projecting portion and the second projecting portion. The first connector includes grooves for receiving the first terminals. The first terminals are pressed-fit into the grooves in the insertion direction of the insertion projection. 
     A board-to-board connector for mating with another connector has a housing and a plurality of terminals. The terminals and housing interact at a reference surface to accurately locate the terminals relative to the housing. The housing includes an elongated recess that extends parallel to a longitudinal axis of the housing and has a plurality of terminal receiving cavities spaced therealong. Each cavity includes a terminal retention wall with a reference surface on one side thereof and a terminal alignment opening extending from the cavity. Each terminals is disposed in a terminal receiving cavity. Each terminal includes a U-shaped retention portion, an L-shaped resilient contact portion extending from the U-shaped retention portion and has a contact projection thereon. A tail portion for interconnection to a circuit member is also provided. The U-shaped retention portion includes first and second spaced apart legs and a connecting portion therebetween with the U-shaped retention portion dimensioned to securely receive the terminal retention wall of the housing between the spaced apart legs. The first leg is positioned along and engages the reference surface in order to accurately position the terminal within the terminal receiving cavity, and a terminal alignment projection extends from the U-shaped retention portion and projects into the terminal alignment opening to further position and secure the terminal within the cavity. 
     A portion of the terminal alignment opening may be collinear with the reference surface. In addition, the reference surface may be generally planar and face the recess. The terminal alignment projection may extend from the first leg of the U-shaped retention portion and may be press-fit within the terminal alignment opening. If desired, the terminal alignment opening may be configured as a bore that extends from the cavity to a mounting face of the connector. In one embodiment, the U-shaped retention portion may be an inverted U-shape and the second leg thereof may have a second projecting portion formed thereon generally facing the contact projection. 
     The first and second connectors are mated along a mating axis, and the first and second spaced apart legs and the terminal alignment projection may all be configured to be generally parallel to the mating axis. The second spaced apart leg may include an engagement projection and the terminal retention wall of the housing may include an engagement portion formed on a side surface thereof to engage the engagement projection when the terminal is fully inserted in the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: 
         FIG. 1  is a sectional view (taken along line A-A in  FIG. 2 ) of a first connector according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of the first connector according to the embodiment; 
         FIG. 3  is a perspective view of two terminals used in the first connector of  FIGS. 1 and 2 . 
         FIG. 4  is a perspective view of a second connector for mating with the connector of  FIGS. 1 and 2 ; 
         FIG. 5  is a sectional view showing a state in which the first and second connectors are mated together; and 
         FIG. 6  is a sectional view of a prior art board-to-board connector. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings in greater detail, first connector  10  and second connector  30  are a pair of mating board-to-board connectors. These connectors are surface mount type connectors mounted on the surface of respective circuit boards or members  51 ,  52 . 
     In the present embodiment, terms for expressing direction, such as up, down, left, right, front, and rear, are used for explaining the structure and action of respective portions of the board-to-board connectors. However, these terms represent respective directions for the case where the board-to-board connectors are used in an orientation shown in the drawings, and must be construed to represent corresponding different directions when the orientation of the board-to-board connectors is changed. 
     Referring to  FIGS. 1-3 , first connector  10  includes a first housing or connector main body  11  integrally formed from an insulative material such as a synthetic resin. As shown in  FIG. 2 , first housing  11  has a shape of a generally rectangular thick plate with a generally rectangular concave portion or slot formed in a mating surface into which second connector  30  is inserted. Although the first connector  10  has a length of about 12 mm, a width of about 3.5 mm and a depth of about 1.7 mm, the size can be changed freely. In the concave portion, a ridge portion or central projection  13  is formed integrally with the first housing  11 . Side wall portions  14  extending parallel to the ridge portion  13  are formed integrally with the first housing  11  such that the side wall portions  14  are located on opposite sides of and spaced from the ridge portion  13 . The ridge portion  13  and the side wall portions  14  project upwardly from the bottom surface of the concave portion and extend along the longitudinal direction of the first housing  11 . Thus, an elongated groove portion or receiving recess  12 , extending along the longitudinal direction of the first housing  11 , is formed on both sides of the ridge portion  13  and each is thus located between the ridge portion  13  and the corresponding side wall portion  14 . As shown in  FIG. 1 , the groove portion  12  is closed by a bottom wall portion  11   a  at the bottom which corresponds to the mounting surface  11   b  of the first housing  11  configured to be mounted on the circuit board  51 . In the preferred embodiment, one ridge portion  13  is provided. However, a plurality of ridge portions may or no ridge portions be provided, and the number of the ridge portions is arbitrary. Although the ridge portion  13  has a width of about 0.8 mm, the size may be changed freely. 
     First-terminal receiving slots  15  or cavities for receiving first terminals  21  are formed such that they extend along the longitudinal axis of connector  10  on the opposite sides of ridge portion  13  and above bottom surfaces of the groove portions  12 . In the preferred embodiment, twenty terminal receiving slots  15  are formed on each side of ridge portion  13  and above the bottom surface of the corresponding groove portion  12  at a pitch of about 0.4 mm. As depicted, twenty terminals  21  are accommodated within the twenty terminal receiving slots  15 , at a pitch of about 0.4 mm. on each side of ridge portion  13 . First-terminal receiving slots  15  include tapered lead-in surfaces or grooves  16  along the upper opening of such slots to facilitate insertion of terminals  21  within slots  15 . The first-terminal receiving slots  15  and the first-terminal lead-in surfaces  16  are continuously and integrally formed as part of housing  11 . 
     First-terminal alignment holes  17  are formed to extend from and be in communication with first terminal receiving slots  15  and penetrate the bottom wall  11   b  in the mating direction “B” ( FIG. 1 ) of the mating connectors. A portion of an inner surface of each first-terminal alignment hole  17  and the inner side surface of the corresponding terminal engaging portions  14   a  are collinear and form a common flat surface  14   b  serving as a housing reference surface or datum. This reference surface  14   b , is a reference for defining the positional relationship between the first housing  11  and the first terminals  21 . As depicted, the housing reference surface  14   b  is planar and extends in the insertion direction of the insertion projections  32  which, in the described embodiment, is the same as mating direction B. Further, engagement portion or shoulder  14   c  for engagement with engagement projections  22   d  of the first terminals  21  is formed on the outer side surface of each engaging portion  14   a.    
     The structure of first terminals  21  is shown in detail in  FIGS. 1 and 3 . Each of the first terminals  21  has a retention portion  22  and a contact portion  24 , and is stamped or blanked from an electrically conductive metal sheet. As such, terminal  21  is generally or substantially planar with a thickness equal to the thickness of the sheet metal from which it is stamped. The retention portion  22  has an inverted-U-shaped profile, and includes a connecting or bridge portion  22   f , and first and second, spaced apart leg portions  22   a  and  22   c , which extend integrally from the connecting portion  22   f  toward the mounting surface  11   b  in the terminal insertion direction. The first leg portion  22   a  is located within housing  11  along reference surface  14   b  and the second leg portion  22   c  is located on the opposite side of terminal engaging portion  14   a  of the housing. The outer side surface of the first leg portion  22   a  is flat, and serves as a terminal reference surface  22   b , which engages reference surface  14   b  to define the positional relationship between housing  11  and terminal  21 . An engagement projection  22   d  for engagement with the engagement portion  14   c  of the first housing  11  is formed on the inner side surface of the second leg portion  22   c  which holds the terminal to the housing. A solder tail portion  22   e  is formed at the distal end of the second leg portion  22   c . The solder tail portion  22   e  projects from the mounting surface  11   b  of the first housing  11  and its lower projection end surface is soldered to a conductive circuit or pad on the surface of the circuit board  51 . 
     The contact portion  24  has a generally L-shaped profile with a first vertical portion  24   a , located near ridge portion  13 , and extending in the mating direction B. Vertical portion  24   a  is accommodated in the terminal accommodation slot  15  formed in a side surface of ridge portion  13 . A bottom portion  24   e , corresponding to the horizontal portion of the letter L, extends in the lateral direction. The first vertical portion  24   a  and bottom portion  24   e  combine to form a deflectable spring arm. A first contact portion  24   b  is formed in the vicinity of the upper end of the first vertical portion  24   a , and a second projecting portion  24   d  is formed in the vicinity of the upper end of the first leg portion  22   a  of retention portion  22 . The first and second projecting portions  24   b  and  24   d  project such that they face each other. The first and second projecting portions  24   b  and  24   d  are located at substantially the same position or height in the mating direction. 
     A path along the first terminal  21  extending from the lower end surface of the solder tail portion  22   e  to the first projecting portion  24   b  is long, and substantially cured. Therefore, the phenomenon of solder wicking is unlikely to occur. That is, there is little likelihood that solder will travel to the first projecting portion  24   b  from solder tail  22   e.    
     Each terminal  21  is inserted into housing  11  from above the housing or “top loaded” as viewed in  FIG. 1 , into the corresponding first-terminal receiving slot  15  and the corresponding lead-in surfaces  16  so that the first leg portion  22   a  and the second leg portion  22   c  grip onto opposite sides of terminal engaging portion  14   a  to retain the first terminal  21  in housing  11 . During assembly, each terminal  21  is moved from the mating surface of housing  11  in the direction in which the first and second leg portions  22   a  and  22   c  project. That is, each terminal  21  is moved downwardly in a position as shown in  FIG. 3  and inserted into housing  11  from the upper side thereof in  FIG. 1 . Retention portion  22  is received in the corresponding groove  16  formed on the upper surface of the side wall portion  14 , and the distal end portion of the first leg portion  22   a  is press-fit into the first-terminal alignment hole  17 . The engagement projection  22   d  of the second leg portion  22   c  slides past and comes into engages the engagement portion  14   c  of the housing  11  preventing terminal  21  from being moved upwardly out of the housing  11 . 
     When each terminal  21  is secured in housing  11 , the bottom portion  24   e  of contact portion  24  is received in the first-terminal receiving slot  15  formed on the bottom surface of the corresponding groove portion  12 . First projecting portion  24   b  projects from the first-terminal receiving slot  15  into the groove portion  12  and second projecting portion  24   d  is located in the first-terminal receiving slot  15 . In such condition, terminal reference surface  22   b  is in contact with the housing reference surface  14   b  to accurately locate terminal  21  in relation to housing  11 . 
     Contact portion  24  is resilient to permit mating and engagement with a mating connector  30 . First vertical portion  24   a  and bottom portion  24   e  deform elastically when first connector  10  is mated with the second connector  30 . Upon deflection, first projecting portion  24   b  is pushed toward the ridge portion  13 . Contact portion  24  reacts by virtue of its resilient property so that the first projecting portion  24   b  and the second projecting portion  24   d  grip the second terminal  41  and the insertion projection  32 , respectively. Retention portion  22  grips the terminal engaging portion  14   a  from both sides by gripping it between the first leg portion  22   a  and the second leg portion  22   c . The cantilevered tip end portion of the first leg portion  22   a  is press fit into the first-terminal alignment hole  17 . Therefore, even when the contact portion  24  engages second connector  30  and elastically deforms, retention portion  22  does not deform, and the terminal reference surface  22   b  does not bend, deflect or more relative to housing  11 . Through such a configuration, uniform contact can be maintained between the terminal reference surface  22   b  and housing reference surface  14   b , and the overall position of each first terminal  21  can be ensured. 
     An additional feature of the disclosed embodiment is that first terminals  21  are not exposed at the lower surface of the first connector  10 , except for the solder tail portions  22   e . The groove portions  12  are closed by the bottom wall portions  11   a  on the mounting surface side. Therefore, conductive circuits can be located on a surface of the circuit board  51  under the lower mating surface  11   b  of the first connector housing  11 . 
     The contact pressure generated when the first contact portion  24   b  of contact portion  24  comes into contact with the contact portion  44   b  of the second terminal  41  is not transmitted to the engagement projection  22   d  or the solder tail portion  22   e  of the retention portion  22 . Therefore, even when the first connector  10  and the second connector  30  are mated, force is not transferred to the solder joint between the solder tail portion  22   e  and the circuit board  51 , thus reducing the likelihood of cracks at the solder joint. 
       FIG. 4  is a perspective view of a second, mating connector  30  which includes a second housing or connector main body  31  integrally formed from an insulative material such as a synthetic resin. As shown in  FIG. 4 , housing  31  has a shape of a generally rectangular thick plate with a length of about 10 mm, a width of about 3 mm, and a thickness of about 1.1 mm. However, the size can be changed freely. Housing  31  has a pair of integrally formed longitudinal side walls  32  that project upwardly from its base and a pair of end walls at opposite ends of the sidewalls. The sidewalls and end walls define an elongated grove portion  33  extending in the longitudinal direction of the second housing  31 . In the disclosed embodiment, there are two sidewalls  32  that act as insertion projections for inserting into recesses  12  of first connector  10 . However, a single insertion projection or three or more insertion projections may be provided by modifying the housing. Although the groove portion  33  has a width of about 0.8 mm, the size may be changed freely. 
     The second housing  31  is formed through over-molding to partially cover second terminals  41  in resin. The second contact portion  44  of each second terminal  41  is embedded in the sidewalls or insertion projections  32  such that, as shown in  FIG. 4 , the surface of the contact portion  44  is exposed at the inner side surface  44   b  and the intermediate surface  44   c , as shown as a top surface in  FIG. 4 , of the insertion projection  32 . Each of the second terminals  41  has a solder tail portion  43  extending outwardly from the lower edge of one of the opposite sides of the second housing  31 . In the disclosed embodiment, twenty terminals  41  are disposed at a pitch of about 0.4 mm on each side. However, the pitch and the number of second terminals  41  may be changed as desired. 
       FIG. 5  is a sectional view showing a state in which the first and second connectors are mated together while they are mounted to their respective printed circuit boards  51 ,  52 . Each second terminal  41  has a solder tail portion  43  and a contact portion  44 , and is stamped and formed from electrically conductive sheet metal. The contact portion  44  has a generally J-shaped profile, and has a vertically extending side wall portion  44   b  having a surface exposed at the inner side surface of the insertion projection  32  in groove portion  33  and a vertically extending distal end portion  44   a  which is embedded in the sidewall or insertion projection  32 . Since the distal end portion  44   a  is embedded in the insertion projection  32 , second terminal  41  is strongly secured within second housing  31 . An intermediate portion  44   c  between the side wall portion  44   b  and the distal end portion  44   a  extends in the lateral direction and is exposed at the top surface (when viewed in  FIG. 4 ) of insertion projection  32 . The inner end (on the side toward the groove portion  33 ) of the solder tail portion  43  is connected to the upper end of the second connection portion  44 , and extends in the lateral direction. Solder tail portion  43  is configured to be soldered to a conductive circuit or pad (not shown) formed on the surface of the circuit board  52 . 
     The surface of the side wall portion  44   b  of the contact portion  44  serves as a contact for contacting the first projecting portion  24   b  of a corresponding first terminal  21 . When the first connector  10  is mated with the second connector  30 , the first projecting portion  24   b  of the first terminal  21  comes into contact with the flat contact portion  44   b  of the contact portion  44 . Since the contact portion  44   b  of the contact portion  44  extends vertically, the first projecting portion  24   b  can continuously wipe the surface of the contact portion  44   b  to thereby produce a sufficient level of wiping effect which is especially important with miniature connectors. Thus, good electrical connection between the first projecting portion  24   b  and the contact portion  44  is likely. 
     Since the second housing  31  is formed through over-molding and covers the joint between the solder tail portion  43  and contact portion  44 , solder is unlikely to travel along the second terminal  41  from solder tail portion  43  to the surface of the contact portion  44   b  during the soldering process. 
     Prior to mating, the first connector  10  and the second connector  30  are positioned such that the mating surface of the first connector  10  and the mating surface of the second connector  30  directly face each other. In this state, the mating surface of the first connector  10  and the mating surface of the second connector  30  are generally parallel to each other, and the circuit board  51  carrying the first connector  10  and the circuit board  52  carrying the second connector  30  are also generally parallel to each other. The first connector  10  and the second connector  30  are moved relatively towards each other whereby they are mated with each other as shown in  FIG. 5 . During mating, ridge portion  13  of first connector  10  is inserted into groove portion  33  of second connector  30 , and the insertion projections or sidewalls  32  of second connector  30  are inserted into the corresponding groove portions  12  of first connector  10 . 
     As a result, the first projecting portion  24   b  of contact portion  24  of each first terminal  21  engages the contact  44   b  of the contact portion  44  of the corresponding second terminal  41 . In addition, second projecting portion  24   d  of contact portion  24  of each first terminal  21  engages the outer side surface of the insertion projection  32 .  FIG. 5  shows a gap present between the second projecting portion  24   d  and the outer side surface of the insertion projection  32  for the sake of clarity. 
     In the disclosed embodiment, the distance between the facing surfaces of the first and second projecting portions  24   b  and  24   d  of contact portion  24  of each first terminal  21  is shorter than the distance between the contact  44   b  of the contact portion  44  of each second terminal  41  and the outer side surface of the insertion projection  32 . As a result of mating of the first connector  10  and the second connector  30  together, the insertion projections  32  of the second connector  30  are inserted into the corresponding groove portions  12  of the first connector  10 , thus deflecting the spring arm of contact portion  24  and increasing the distance between the facing surfaces of the first and second projecting portions  24   b  and  24   d  of first terminal  21 . Therefore, the insertion projections  32  to which the second terminals  41  are mounted are gripped by the first projecting portions  24   b  of the first vertical portions  24   a  and the second projecting portions  24   d  of the first leg portion  22   a . The end of the first projecting portion  24   b  of the contact portion  24  of each first terminal  21  engages contact  44   b  of the contact portion  44  of the corresponding second terminal  41 . 
     Further, when each of the insertion projections  32  of the second connector  30  is inserted into the corresponding groove portion  12  of the first connector  10 , the tip portion of the first projecting portion  24   b  of the first connection portion  24  of the first terminal  21  moves while sliding along the flat surface of the contact portion  44   b . Therefore, a scraping or wiping effect is produced, so that substances which hinder electrical continuity, such as dust and oxides adhering to the tip end of the first projection portion  24   b  and the surface of the contact portion  44   b , are removed through wiping. Therefore, reliable electrical continuity is secured at the contact portion. 
     When disengaging the first connector  10  from the second connector  30 , the first connector  10  and the second connector  30  are pulled away from each other. As a result, the insertion projections  32  of the second connector  30  are pulled upwardly from the respective groove portions  12  of the first connector  10 , while being gripped by the first projecting portion  24   b  and the second projecting portion  24   d  of the first connection portion  24  of each first terminal  21 . An upwardly pulling force acts on the first projecting portion  24   b , and a rotational moment acts on the contact portion  24  to attempt to separate such that the terminal reference surface  22   b  from housing reference surface  14   b . However, since the tip end portion of the first leg portion  22   a  is press-fit into the first-terminal alignment hole  17 , the retention portion  22  does not elastically deform, and the terminal reference surface  22   b  is not displaced relative to reference surface  14   b . Therefore, the overall position of the first terminal  21  is very stable, even during mating and unmating. 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.