Patent Publication Number: US-11031709-B2

Title: Electrical connector for circuit boards and mounting arrangement for electrical connector for circuit boards

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2018-172303, filed Sep. 14, 2018, the contents of which are incorporated herein by reference in its entirety for all purposes. 
     TECHNICAL FIELD 
     The present invention relates to an electrical connector for circuit boards mounted to a circuit board and a mounting arrangement for an electrical connector for circuit boards. 
     RELATED ART 
     Known connectors of this type include the connector disclosed in Patent Document 1. The connector disclosed in Patent Document 1 is a so-called right-angle connector in which, upon mounting to a circuit board, a direction parallel to a mounting face of the circuit board is used as the direction of plugging and unplugging of a counterpart connector. In this connector, the terminals include lower terminals that have their contact portions, which are used for contacting the counterpart connector, oriented in the above-mentioned direction of plugging and unplugging, and that have their contact portions located at a lower level closer to the mounting face, and upper terminals at an upper level, which are located thereabove, with both the lower and the upper terminals bent at right angles at intermediate locations and their lower end sections used as connecting portions mounted to the circuit board. The connecting portions of the lower terminals are passed through terminal through-holes in the circuit board and, after installation through the terminal through-holes, are solder-connected to lands formed on the perimeter edge of the terminal through-holes; the upper terminals have their connecting portions bent into surface contact with the lands on the surface of the circuit board and solder-connected to said lands while in surface contact therewith. 
     In the connector of Patent Document 1, the housing that retains the terminals is surrounded by and retained in a case-like shell, with each of the multiple attachment legs of said shell installed through a corresponding shell through-hole in the circuit board, and, in the same manner as in the case of the lower terminals, upon installation through a shell through-hole, said attachment legs are solder-connected to a land formed on the surface of the circuit board on the perimeter edge of said shell through-hole. Electrically, the shell functions as a shielding case, and mechanically as a reinforcing fitting. 
     Therefore, in the connector of Patent Document 1, the strength of attachment of the connector to the mounting face is improved because each connecting portion of the lower terminals is solder-connected to a land on the perimeter edge of a terminal through-hole and the attachment legs of the shell are solder-connected to the lands on the perimeter edge of the shell through-holes. 
     PATENT DOCUMENTS 
     [Patent Document 1] 
     Japanese Patent Application Publication No. 2014-157790. 
     SUMMARY 
     Problems to be Solved 
     However, in the connector of Patent Document 1, the attachment legs of the shell are installed through shell through-holes disposed in a spaced-apart relationship to the rows of the terminal through-holes of the above-mentioned lower terminals in the array direction of said terminal through-holes as well as in a direction perpendicular to said array direction, and are solder-connected to the lands on their perimeter edge. 
     The above-mentioned shell through-holes are disposed and formed in alignment with the locations of the respective attachment legs of the shell, on both sides outside the array range of the above-mentioned terminal through-holes, at locations spaced away from the terminal through-holes in a direction perpendicular to the array direction. In other words, the attachment legs of the above-mentioned shell must be provided at locations spaced away from said terminal through-holes both in the array direction of the lower terminals and in a direction perpendicular thereto. Forming multiple lands at mutually spaced locations on the circuit board increases the extent of the area necessary on the circuit board for multiple land formation, which includes land-free zones between the lands, and increases the size of both the connector and devices using said connector. 
     In addition to signal terminals, the terminals of this type of connector include power supply terminals. The power supply terminals, which supply electrical power used for signal control in the signal terminals, are larger in size than the signal terminals because they use electric currents that are stronger than those of the signal terminals. Therefore, when the connecting portions of such power supply terminals are installed through terminal through-holes other than the through-holes used for the signal terminals and are solder-connected to lands on the perimeter edge of the through-holes, the through-holes and lands become larger than the through-holes and lands used for the signal terminals commensurately with the increase in the dimensions of the power supply terminals. Furthermore, when, in addition to these power supply terminals, the attachment legs of the above-mentioned shell or attachment legs forming part of reinforcing fittings used in the connector are disposed at locations spaced away from the terminals as described in Patent Document 1, the increase in connector size becomes even more significant. 
     With these circumstances in mind, it is an object of the present invention to provide an electrical connector for circuit boards and a mounting arrangement for said electrical connector for circuit boards in which the connector has reinforcing fittings and, even if the attachment legs of the reinforcing fittings are solder-connected to a land on a circuit board, an increase in the size of the connector can be avoided without increasing the extent of the area necessary for land formation on the circuit board that is required for land placement. 
     Technical Solution 
     It is an object of the invention to provide an electrical connector for circuit boards and a mounting arrangement therefore in which the extent of the area necessary for land formation on the circuit board is minimized. 
     The inventive electrical connector for circuit boards, which is provided with a housing of an electrically insulating material, signal terminals and non-signal terminals serving as at least one of ground terminals and power supply terminals made of a metallic material and retained within said housing, and reinforcing fittings attached to the housing, is mounted to a circuit board. 
     In the present invention, such an electrical connector for circuit boards is characterized in that the non-signal terminals are located outside the array range of the signal terminals, the reinforcing fittings are located adjacent to said non-signal terminals, the non-signal terminals have connecting legs for connection to the circuit board, the reinforcing fittings have attachment legs for attachment to the circuit board, and the connecting legs of the non-signal terminals and the attachment legs of the reinforcing fittings are located adjacent to each other in the above-mentioned array direction within a single through-hole provided in a common land formed on the circuit board and can be solder-connected to said land. 
     In accordance with the thus-configured present invention, the connecting legs of the non-signal terminals and the attachment legs of the reinforcing fittings are solder-connected to a single common land within a single common through-hole. For this reason, there are no longer any land-free zones between the above-mentioned connecting legs and attachment legs in the area necessary for land formation. As a result, the extent of the area required for land formation is minimized both in the above-mentioned array direction and in a direction perpendicular to said array direction, and the connector is made more compact. In addition, as a result of being located within a single common through-hole, the above-mentioned connecting legs and attachment legs are solder-connected to a single common land in close proximity to one another and the solder strength of the connecting legs and attachment legs is improved. 
     In the present invention, the housing can be adapted such that the receiving portion used for plugging and unplugging a counterpart connector is formed with its opening oriented such that the direction of plugging and unplugging of said counterpart connector is parallel to the mounting face of the circuit board. In this type of connector, even if the force used when plugging and unplugging a counterpart connector that operates in a direction perpendicular to the direction in which the connecting legs and attachment legs extend acts as a shearing force or a bending moment on the attachment legs and connecting portions that have been solder-connected in close proximity in a manner that imparts improved strength, the above-mentioned connecting portions and attachment legs will be able to adequately counteract it. 
     In the present invention, the non-signal terminals and the reinforcing fittings are made of sheet metal and can be adapted such that at least the through-thickness direction of the attachment legs of the reinforcing fittings intersects the direction of plugging and unplugging of the counterpart connector. In accordance with this embodiment, the attachment legs of the reinforcing fittings are typically of larger dimensions than the connecting portions of the non-signal terminals and, therefore, have higher strength. In addition, the above-mentioned force used when unplugging a counterpart connector can be adequately counteracted because the through-thickness direction of the attachment legs is oriented such as to intersect the direction of plugging and unplugging of the counterpart connector. 
     When this inventive electrical connector for circuit boards is disposed on a circuit board, the attachment legs of the reinforcing fittings and the connecting portions of the non-signal terminals of said electrical connector for circuit boards are located within a single through-hole in the circuit board and are solder-connected to a land on the perimeter edge of the through-hole, thereby forming a mounting arrangement of the electrical connector for circuit boards in conjunction with the circuit board. 
     Technical Effect 
     According to the present invention as described above, in a connector having reinforcing fittings in addition to signal terminals and non-signal terminals, the connecting legs of the non-signal terminals and the attachment legs of the reinforcing fittings are adjacent to each other in the array direction of the signal terminals within a single common through-hole located in a single common land formed on a circuit board and are solder-connected to said land, as a consequence of which, due to the fact that the connecting legs of the non-signal terminals and the attachment legs of the reinforcing fittings are located within a single through-hole and said through-hole is located in the array direction of the signal terminals outside the array range of the signal terminals, no land-free zones are present within the area necessary for the formation of the land formed across the surface of the circuit board on the perimeter edge of the through-hole between the connecting portions of the above-mentioned non-signal terminals and the attachment legs of the reinforcing fittings, as a result of which the area may be smaller both in the above-mentioned array direction and in a direction perpendicular to the array direction, and the connector is made more compact; and, furthermore, solder-connecting the connecting portions of the above-mentioned non-signal terminals and the attachment legs of the reinforcing fittings to the single common through-hole in close proximity to one another provides the benefit of obtaining an electrical connector for circuit boards and a mounting arrangement for an electrical connector for circuit boards possessing increased attachment strength and capable of adequately counteracting external forces, more particularly, forces exerted when plugging and unplugging a counterpart connector. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a perspective view illustrating a first connector and a counterpart second connector in a state that immediately precedes mating in an embodiment of the present invention. 
         FIG. 2  illustrates a Z-X plane cross-section view of the first connector shown in  FIG. 1  taken across the upper signal terminals and lower signal terminals at the same location in the terminal array direction. 
         FIG. 3  illustrates a Z-X plane cross-section view of the first connector shown in  FIG. 1  taken across the upper power supply terminals and lower power supply terminals at the same location in the terminal array direction. 
         FIG. 4  illustrates a Z-X cross-section view of the first connector shown in  FIG. 1  taken at the location of a reinforcing fitting in the terminal array direction. 
         FIG. 5  illustrates a plan view of the mounting range on the circuit board, within which the first connector shown in  FIG. 1  is mounted. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view illustrating a first connector I and a counterpart second connector II to be mated thereto in a state that immediately precedes mating in an embodiment of the present invention. In  FIG. 1  and subsequent figures, spatial coordinates X, Y, Z are configured for the two connectors I and II for ease of understanding of directions. X is the direction of plugging and unplugging of the two connectors I, II, where the forward direction from the second connector II to the first connector I is designated as X 1  and the opposite rearward direction is designated as X 2 ; Y is the terminal array direction of the two connectors I, II, where one direction is designated as Y 1  and the opposite direction as Y 2 ; and Z is the height direction of the connector, where the upward direction is designated as Z 1 , and the downward direction is designated as Z 2 . 
     The above-mentioned first connector I, wherein its bottom face (surface located at the lower Z 2  end) is mounted to a circuit board (not shown) and the attachment legs of the reinforcing fittings and the connecting legs of the hereinafter-described power supply terminals that protrude downward along the Z 2 -axis are disposed through a through-hole in the circuit board and solder-connected to said circuit board, is a so-called right-angle connector in which a direction perpendicular to the connecting legs and attachment legs, i.e., a direction parallel to the mounting face of the circuit board, is used as the direction of plugging and unplugging X of a counterpart second connector II, and the second connector II is formed such as to be mated with, and extracted from, the first connector I in said direction of plugging and unplugging X. The first connector I, the second connector II, the circuit board to which the first connector I is mounted, and, furthermore, the mounting of the first connector I to the circuit board will be described below. 
     &lt;First Connector I&gt; 
     The first connector I has a housing  10  of a substantially rectangular parallelepiped-like external configuration made of an electrically insulating material, as well as upper signal terminals  20  and lower signal terminals  30 , which are retained in place in said housing  10  at predetermined intervals in the terminal array direction Y, i.e., in the connector width direction, and which have contact portions disposed in two upper and lower rows in the height direction Z of the connector; upper power supply terminals  40  and lower power supply terminals  50 , which are retained within the housing  10  at locations outside the array range of the above-mentioned upper signal terminals  20  and lower signal terminals  30  in the terminal array direction Y; and, furthermore, reinforcing fittings  60 , which are retained within the housing  10  at outer locations thereof. 
     As can be seen in  FIG. 1 , in the first connector I, the multiple upper signal terminals  20  and lower signal terminals  30  are arranged in the terminal array direction Y within the housing  10 , the upper power supply terminals  40  (not shown in  FIG. 1 ) and lower power supply terminals  50  are located in the same direction outside their array range, and, furthermore, the reinforcing fittings  60  are located at outer locations thereof. 
       FIG. 2  shows a Z-X plane cross-section of the connector I taken at the location of an arbitrary pair comprising an upper signal terminal  20  and a lower signal terminal  30  in the terminal array direction Y,  FIG. 3  shows a Z-X plane cross-section of the connector I taken at the location of an upper power supply terminal  40  and a lower power supply terminal  50 , and  FIG. 4  shows a Z-X plane cross-section of the connector I at the location of a reinforcing fitting  60 . 
     As can be seen in  FIGS. 1 to 4 , the housing  10  has a receiving portion  11  that is open at the rear along the X 2 -axis, i.e., in the direction of extraction of the second connector II, in the top half of the housing  10 , and recesses  14 B, which are constituted by “cavities” intended to provide ribs  14 A with a view to improving the strength of the housing  10  and preventing the warping of said housing  10 , are formed in the bottom half of said housing  10 . 
     The elongated receiving portion  11  extends between two lateral walls  12  located at both ends in the terminal array direction Y, and, in the height direction Z of the connector, this portion is formed between a top wall  13  and a partition  14  provided at an intermediate location in the height direction Z of the connector. A plate-shaped terminal array protrusion  16 , which extends to the rear along the X 2 -axis from a front end wall  15  of the housing  10  located at the front end in the X 1  direction, is provided within said receiving portion  11 , and an annular receiving space  11 A, which receives the mating protrusion of the hereinafter-described second connector II, is formed within the above-mentioned receiving portion  11  around the periphery of the terminal array protrusion  16 . Terminal array grooves  16 A,  16 B, which are formed on the top and bottom faces of the above-mentioned terminal array protrusion  16 , extend in the direction of plugging and unplugging X at predetermined intervals in the terminal array direction Y. The terminal array grooves  16 A,  16 B are respectively in communication with terminal press-fit holes  17 A,  17 B formed by passing through the above-mentioned front end wall  15  of the housing  10 . 
     The terminals of the first connector I comprise upper signal terminals  20 , lower signal terminals  30 , upper power supply terminals  40 , and lower power supply terminals  50 . If necessary, the first connector I can be selectively provided with a shielding plate, in which case the ground terminals of the shielding plate, the upper power supply terminals  40 , and the lower power supply terminals  50  are collectively referred to as non-signal terminals in contradistinction to the upper signal terminals  20  and lower signal terminals  30 . 
     As can be seen in  FIG. 2 , multiple upper signal terminals  20  and lower signal terminals  30 , which are fabricated by molding and bending strip-shaped members of sheet metal, are respectively arranged in the terminal array direction Y. 
     The upper signal terminals  20  have contact arm portions  21 , which extend in the direction of plugging and unplugging X, leg portions  22 , which extend from the ends of the base portions  21 A of said contact arm portions  21  outside of the housing  10  downward along the Z 2 -axis in the height direction Z of the connector, and connecting portions  23 , which are obtained by bending said leg portions  22  at the lower ends such as to make them parallel to the mounting face of the circuit board and bring them into surface contact with said circuit board. Said connecting portions  23  are arranged along the lower forward edge of the bottom wall  18  of the housing  10 . 
     The contact arm portions  21  are formed by folding over the strip-shaped members of sheet metal constituting the upper signal terminals  20  upon itself, and their through-thickness direction is the terminal array direction Y. Said contact arm portions  21  have base portions  21 A, which are press-fitted rearwardly along the X 2 -axis into the terminal press-fit holes  17 A formed in the front end wall  15  of the housing  10 , and resilient arm portions  21 B, which extend from said base portions  21 A to the rear along the X 2 -axis within the above-mentioned terminal array grooves  16 A on the top face of the terminal array protrusion  16 . Engagement projections  21 A- 1 , which prevent extraction by biting into the wall surface of the terminal press-fit holes  17 A, are provided in the top base portions  21 A. Upward-protruding contact portions  21 B- 1 ,  21 B- 2  are provided at locations slightly offset with respect to each other in the direction of plugging and unplugging X at the distal ends (rear ends in the X 2  direction) of the above-mentioned resilient arm portions  21 B. The two contact portions  21 B- 1 ,  21 B- 2  are formed, respectively, on one side and the other side obtained by folding over the contact arm portions  21  upon itself as discussed before. 
     The lower signal terminals  30  have contact arm portions  31 , which extend in the direction of plugging and unplugging X; leg portions  32 , which extend from the ends of the base portions  31 A of said contact arm portions  31  outside of the housing  10  downward along the Z 2 -axis in the height direction Z of the connector; transverse portions  34 , which are obtained by bending said leg portions  32  at the lower ends to extend along the bottom face of the housing  10  to the rear along the X 2 -axis; and connecting portions  33 , which are obtained by bending the rear ends of said transverse portions  34  downward along the Z 2 -axis and then bending such as to make them parallel to the mounting face of the circuit board and bring them into surface contact with said circuit board. Said connecting portions  33  are arranged along the lower rear edge of the bottom wall  18  of the housing  10 . In such lower signal terminals  30 , the contact arm portions  31 , leg portions  32 , and transverse portions  34  create a lateral U-shaped configuration open to the rear along the X 2 -axis, which is supported due to the fact that it straddles the housing  10 . For this reason, even if the lower signal terminals  30  are subject to a friction force generated by counterpart terminals and acting rearward along the X 2 -axis during rearward extraction of the counterpart second connector II in the X 2  direction, deformation during extraction is avoided because of the support provided by the housing  10 . 
     The contact arm portions  31  are formed by folding over the strip-shaped members of sheet metal constituting the lower signal terminals  30  upon itself, and their through-thickness direction is the terminal array direction Y. Said contact arm portions  31  have base portions  31 A, which are press-fitted rearward along the X 2 -axis into the terminal press-fit holes  17 B formed in the front end wall  15  of the housing  10 , and resilient arm portions  31 B, which extend from said base portions  31 A rearward along the X 2 -axis within the above-mentioned terminal array grooves  16 B on the bottom face of the terminal array protrusion  16 . Engagement projections (not shown in  FIG. 2 ), which prevent extraction by biting into the wall surface of the terminal press-fit holes  17 B, are provided in the top base portions  31 A. Downward-protruding contact portions  31 B- 1 ,  31 B- 2  are provided at locations slightly offset with respect to each other in the direction of plugging and unplugging X at the distal ends (rear ends in the X 2  direction) of the above-mentioned resilient arm portions  31 B. These two contact portions  31 B- 1 ,  31 B- 2  are formed, respectively, on one side and the other side obtained by folding over the contact arm portions  31  upon itself as discussed before. 
     Now, as can be seen in  FIG. 3 , the power supply terminals, which are non-signal terminals comprised of the upper power supply terminals  40  and the lower power supply terminals  50 , are provided in the terminal array direction Y on the outside of the array range on both sides of the above-mentioned upper signal terminals  20  and lower signal terminals  30 . The upper power supply terminals  40  and lower power supply terminals  50  are formed by bending strip-shaped members of sheet metal in the through-thickness direction thereof, and their width (terminal width) in the terminal array direction Y across their major faces perpendicular to the through-thickness direction is wider than the terminal width of the upper signal terminals  20  and lower signal terminals  30 . 
     The above-mentioned upper power supply terminals  40  have a contact arm portion  41 , which extends rearward along the X 2 -axis in the direction of plugging and unplugging X along the bottom face of the upper wall  13  of the housing  10 , a front leg portion  42 , which is obtained by bending the front end of said contact arm portion  41  and extends downward along the Z 2 -axis along the front surface of the front end wall  15  of the housing  10 , and a connecting portion  43 , which is obtained by bending the lower end of said front leg portion  42  at the forward edge of the above-mentioned bottom wall  18  and extends forward along the X 1 -axis, with said connecting portion  43  solder-connected to the circuit board in surface contact therewith. 
     The distal end of the above-mentioned contact arm portion  41 , which is oriented rearward along the X 2 -axis, is bifurcated into two branches and, at the same time, the branch portions are bent downward along the Z 2 -axis in a V-shape and have two contact portions  41 A,  41 B in a side-by-side arrangement. The contact arm portion  41  possesses resilience that results in flexure in the height direction Z of the connector, and when the above-mentioned contact portions  41 A,  41 B are in contact with the corresponding power supply terminals of the counterpart second connector II, the resilient flexure generates contact pressure against the corresponding power supply terminals. 
     The above-mentioned lower power supply terminals  50  have a contact arm portion  51 , which is located along the top face of the partition  14  of the housing  10  and extends to the rear along the X 2 -axis in the direction of plugging and unplugging X, a front leg portion  52 , which is obtained by bending the front end of said contact arm portion  51  and extends downward along the Z 2 -axis along the front surface of the front end wall  15 , a bottom arm portion  53 , which extends to the rear along the X 2 -axis along the bottom face of the above-mentioned bottom wall  18  from the lower end of said front leg portion  52 , and a connecting leg  54 , which is obtained by bending said bottom arm portion  53  at the rear edge of the above-mentioned bottom wall  18  and extends downward along the Z 2 -axis. The above-mentioned contact arm portion  51 , front leg portion  52 , and bottom arm portion  53 , which form a lateral U-shaped configuration open to the rear along the X 2 -axis, are mounted to the housing  10  so as to straddle the top face of the above-mentioned partition  14  of the housing  10  and the bottom face of the bottom wall  18  rearward along the X 2 -axis, and, since this housing  10 , as described hereinafter, is firmly retained in place by the reinforcing fittings  60 , the lower power supply terminals  50  are securely engaged without decoupling from the above mentioned housing  10  even when acted upon by a friction force acting rearward along the X 2 -axis during extraction of the counterpart second connector II. 
     As can be seen in  FIG. 3 , the above-mentioned contact arm portion  51 , which is shaped to be vertically symmetrical to the contact arm portion  41  of the upper power supply terminals  40 , has its distal end, which is oriented rearward along the X 2 -axis, bifurcated into two branches, with the branch portions bent upward along the Z 1 -axis in an inverted V-shape and having two contact portions  51 A,  51 B in a side-by-side arrangement. The contact arm portion  51  possesses resilience that results in flexure in the height direction Z of the connector, and when the above-mentioned contact portions  51 A,  51 B are in contact with the corresponding power supply terminals of the counterpart second connector II, the resilient flexure generates contact pressure against the corresponding power supply terminals. 
     The connecting legs  54  of the above-mentioned lower power supply terminals  50 , which have major faces with planar surfaces in the Y-Z plane including the terminal array direction Y and the height direction Z of the connector, in other words, major faces perpendicular to the direction of plugging and unplugging X, extend downward along the Z 2 -axis in a configuration tapered toward the lower ends. 
     Now, as can be seen in  FIG. 4 , the reinforcing fittings  60  are fabricated by stamping out from a metal sheet of a larger thickness than that of the non-signal terminals, i.e., the upper signal terminals  20 , lower signal terminals  30 , upper power supply terminals  40 , and lower power supply terminals  50 . As shown in  FIG. 4 , the reinforcing fittings  60 , which are shaped in an inverted L configuration, have a retained arm  61  oriented forward along the X 1 -axis from the rear face of the housing  10 , and an attachment leg  62  extending downward along the Z 2 -axis from the rear end of said retained arm  61 . Said attachment legs  62  are located along the same line in the terminal array direction Y as the connecting portions  33  of the lower signal terminals  30  and the connecting legs  54  of the lower power supply terminals  50  and, moreover, are adjacent to the connecting legs  54  of the lower power supply terminals  50  in the same direction. These reinforcing fittings  60  are mounted into fitting grooves  19  formed as slits of an inverted L-shaped configuration in the housing  10 . Said fitting grooves  19  of the housing  10  have a retaining groove  19 A, into which the above-mentioned retained arm  61  is press-fitted forward along the X 1 -axis, and a holding groove  19 B, which holds the attachment leg  62 . At its bottom edge, the retained arm  61  of the above-mentioned reinforcing fittings  60  has an engagement projection  61 A that bites into the surface of the retaining groove  19 A and prevents extraction of the reinforcing fittings  60 . The attachment legs  62 , which have major faces with planar surfaces in the Z-X plane including the direction of plugging and unplugging X and the height direction Z of the connector, in other words, major faces parallel to the direction of plugging and unplugging X, extend downward along the Z 2 -axis in a configuration tapered toward the lower ends. 
     In this manner, the attachment legs  62  of said reinforcing fittings  60  are located in a direction in which their major faces forming planar surfaces are at right angles to the connecting legs  54  of the lower power supply terminals  50  described above. 
     &lt;Second Connector&gt; 
     Since the second connector II to be mated to the first connector I is not material to the present invention, the discussion below will focus only on certain aspects of engagement with the first connector I. 
     As can be seen in  FIG. 1 , the second connector II is a connector that is connected to the first connector I via insertion forward along the X 1 -axis in the direction of plugging and unplugging X and extracted therefrom rearward along the X 2 -axis, with its rear face mounted to another circuit board (not shown). Therefore, the mounting face (circuit side) of the circuit board to which the first connector I is mounted and that of the other circuit board to which the above-mentioned second connector II is mounted are mutually perpendicular. 
     The second connector II has a housing  70  of a substantially rectangular parallelepiped-like external configuration made of an electrically insulating material, which is provided with a mating protrusion  72  mated with the annular receiving space  11 A of the receiving portion  11  of the first connector I, as well as upper signal terminals  80 , lower signal terminals  90 , upper power supply terminals  100 , and lower power supply terminals  110  made of sheet metal, which are retained in place in said housing  10 . 
     The above-mentioned housing  70  has a housing main body portion  71 , which is located rearward along the X 2 -axis, and a mating protrusion  72 , which protrudes forwardly along the X 1 -axis from said housing main body portion  71 . Said mating protrusion  72  has upper and lower walls located at the top and bottom in the height direction Z of the connector (not shown in the figures) and lateral walls  72 A connecting the ends of the above-mentioned upper and lower walls in the terminal array direction Y, with these upper, lower, and lateral walls forming a tubular body open forward along the X 1 -axis. This tubular body enters the annular receiving space  11 A of the second connector II and the terminal array protrusion  16  of the first connector I enters the interior space of said tubular body, thereby mating the two connectors I, II. 
     The above-mentioned upper signal terminals  80  and lower signal terminals  90 , which are fabricated to have vertically symmetrical shapes, have contact portions (not shown in  FIG. 1 ) located within the above-mentioned mating protrusion  72 , connecting portions  81 ,  91  located outside of the housing  70  and solder-connected to a circuit board, and resilient portions  82 ,  92  of a substantially S-shaped configuration that couple the contact portions and the connecting portions  81 ,  91 . The contact portions of the above-mentioned upper signal terminals  80  are located on the bottom face of the upper wall of the mating protrusion  72 , and the contact portions of the lower signal terminals  90  are located on the top face of the lower wall. The connecting portions  81  of the above-mentioned upper signal terminals  80  and the connecting portions  91  of the lower signal terminals  90  are bent in an L-shaped configuration so as to be parallel to the mounting face of the circuit board. 
     The above-mentioned upper power supply terminals  100  and lower power supply terminals  110 , which are fabricated to have vertically symmetrical shapes, have contact portions (not shown in  FIG. 1 ) located within the above-mentioned mating protrusion  72 , connecting portions  101 ,  111  located outside of the housing  70  and solder-connected to a circuit board, and resilient portions  102 ,  112  of a substantially S-shaped configuration that couple the contact portions and the connecting portions  101 ,  111 . The contact portions of the above-mentioned upper power supply terminals  100  are located on the bottom face of the upper wall of the mating protrusion  72 , and the contact portions of the lower power supply terminals  110  are located on the top face of the lower wall. The connecting portions  101  of the above-mentioned upper power supply terminals  100  and the connecting portions  111  of the lower power supply terminals  110  are bent in an L-shaped configuration so as to be parallel to the mounting face of the circuit board. 
     &lt;Circuit Board&gt; 
       FIG. 5 , which is a plan view of the circuit board P that has the first connector I mounted thereto, taken in the height direction Z of the connector, shows the area of the section where the first connector I is mounted. The lands used for solder-connecting the connecting portions of the signal terminals, connecting legs of the power supply terminals, and attachment legs of the reinforcing fittings are formed on the mounting face of the circuit board P. Said lands include signal terminal lands P 1 , power supply terminal lands P 2 , and common lands P 3  shared by the power supply terminals and the reinforcing fittings. 
     The signal terminal lands P 1  consist of multiple upper signal terminal lands P 1 - 1  and multiple lower signal terminal lands P 1 - 2  disposed in two rows. The upper signal terminal lands P 1 - 1  are provided at locations with which the connecting portions  23  of the upper signal terminals  20  are in surface contact, and the lower signal terminal lands P 1 - 2  are provided at locations with which the connecting portions  33  of the lower signal terminals  30  are in surface contact. 
     The width of the power supply terminal lands P 2 , which are located outside the array range of the upper signal terminal lands P 1 - 1  at locations with which the connecting portions  43  of the upper power supply terminals  40  are in surface contact, is wider than that of the above-mentioned upper signal terminal lands P 1 - 1 . 
     The common lands P 3 , which are located outside the array range of the lower signal terminal lands P 1 - 2  and are formed on the mounting face so as to extend around the periphery of a through-hole PT holding a connecting leg  54  of a lower power supply terminal  50  and an attachment leg  62  of a reinforcing fitting  60  adjacent thereto, are considerably wider than the power supply terminal lands P 2 , to which the connecting portions  43  of the above-mentioned upper power supply terminals  40  are solder-connected. 
     &lt;Mounting of First Connector I to Circuit Board P&gt; 
     The first connector I is mounted to the circuit board P via solder connection, thereby forming a mounting arrangement of the electrical connector for circuit boards. 
     Such mounting is accomplished by disposing the first connector I at a predetermined location on the circuit board P and then solder-connecting it to the circuitry. When the first connector I is disposed at a predetermined location on the circuit board P, the connecting portions  23  of the upper signal terminals  20  are respectively disposed on and solder-connected to the surface of the upper signal terminal lands P 1 - 1 , the connecting portions  33  of the lower signal terminals  30  are disposed on and solder-connected to the surface of the lower signal terminal lands P 1 - 2  and, in addition, the connecting portions  43  of the upper power supply terminals  40  are disposed on and solder-connected to the surface of the power supply terminal lands P 2 . On the other hand, the connecting legs  54  of the lower power supply terminals  50  and the attachment legs  62  of the reinforcing fittings  60  are placed within a single common through-hole PT or positioned so as to pass through said through-hole PT and then solder-connected together to a common land P 3  formed on the mounting face so as to extend around the periphery of said through-hole PT. Solder-attaching the connecting legs  54  of the above-mentioned lower power supply terminals  50  and the attachment legs  62  of the reinforcing fittings  60  to a common land P 3  within a single common through-hole PT causes the above-mentioned connecting legs  54  and attachment legs  62  to reinforce each other, thereby enhancing their strength against the shearing forces or bending moments acting thereon during extraction of the counterpart second connector II. Therefore, the housing  10  is firmly retained in place. Furthermore, since the attachment legs  62  of the reinforcing fittings  60  are typically fabricated with larger dimensions than those of the connecting legs  54  of the power supply terminals  50 , the increase in strength is pronounced. Since a single common through-hole PT is sufficient, forming two through-holes in a spaced-apart relationship, as was the case in the past, is no longer needed, as a result of which no land-free zones are required between the through-holes and, therefore, the area necessary for land formation can be minimized. 
     Thus, the first connector I is mounted to the circuit board P and a mounting arrangement of the electrical connector for circuit boards is obtained. 
     As far as the second connector II is concerned, the connecting portions  81  of the upper signal terminals  80 , connecting portions  91  of the lower signal terminals  90 , connecting portions  101  of the upper power supply terminals  100 , and connecting portions  111  of the lower power supply terminals  110  are solder-connected to the respectively corresponding circuits of the other circuit board, after which the mating protrusion  72  of the second connector II is mated with the receiving portion  11  of the first connector I and the second connector II is placed in electrical communication with the first connector I. 
     The present invention is not limited to the illustrated and described right-angle connectors and is also applicable to connectors of the type where the counterpart second connector is plugged and unplugged in a direction perpendicular to the mounting face of the circuit board, to which the first connector is mounted. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
           10  Housing 
           20 ,  30  Signal terminals 
           40 ,  50  Power supply terminals (non-signal terminals) 
           54  Connecting leg 
           60  Reinforcing fitting 
           62  Attachment leg 
         P Circuit board 
         P 3  Land (common land) 
         PT Through-hole 
         I Electrical connector for circuit boards (first connector)