Patent Publication Number: US-7901218-B2

Title: Receptacle and a plug with fixtures to attach to substrates and engaging each other to form a power supply contact

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Japan Patent Application No. 2009-44980, filed on Feb. 27, 2009, in the Japan Patent Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     This invention relates to electrical connectors for use with electric and electronic appliances such as cell-phones, small type personal computers, and the like, and more particularly to an electrical connector capable of sufficiently holding electrical connections even if being subjected to accidental forces and having fixtures which can also be used as power supply contacts other than their inherent function. 
     In general, when substrates are interconnected, it is usual to use two connectors each having the respective substrate connected thereto by soldering or the like. The two connectors can be coupled to each other. 
     As examples of such connectors for connecting substrates proposed by the applicant of the present application, incorporated by reference herein are Japanese Utility Model Application Laid Open No. H05-69,873 (1993) (Patent Literature No. 1), Japanese Utility Model Application Laid Open No. H07-16,381 (1995) (Patent Literature No. 2), and Japanese Patent Application Laid Open No. 2007-18,785 (U.S. Pat. No. 7,374,432 Patent Literature No. 3). 
     The Japanese Utility Model Application Laid Open No. H05-69,873 (Patent Literature No. 1) discloses a connector for avoiding obliquely mis-insertion of a mating connector. For realizing such an object, two square rod shaped coupling members of different sizes are used for the pair of coupling connectors. By this, such a mis-insertion can be avoided. 
     The Japanese Utility Model Application Laid Open No. H07-16,381 (Patent Literature No. 2) discloses a connector realizing a definite locking force and giving a clear indication of the completion of an electric coupling with a short coupling length by providing a protrusion on a male contact and a recess on a mating female contact. The indication is given by a click tone at the coupling. 
     The Patent Application Laid Open No. 2007-18,785 (U.S. Pat. No. 7,374,432) (Patent Literature No. 3) discloses a connector having a floating coupling feature with a simple construction using a special crank shaped contact. 
     Recently, there are increasing demands from customers for narrower pitches of contacts, and for miniaturization and reduced overall height of connectors. Moreover, there has been a requirement for improvement in the toughness of connectors against accidental forces experienced when connectors between substrates are being fitted with each other. In the case of existing connectors between substrates, a rated current of a unit contact is of the order of 0.4 A. However, it is often required to convey power having a current of an order of 1 A. In such a case, it is unavoidable to use multiple terminals (contacts) for power supply purposes. 
     With the constructions as disclosed in the above Patent Literatures, although they comply with the requirements for narrower pitches of conductors and miniaturization and reduced overall height of connectors, they do not satisfy the need to improve toughness against accidental forces in handling and do not conduct a current of the order of 1 A without using plural terminals for each current supply unit. 
     SUMMARY OF THE INVENTION 
     In view of the problems with the prior art described above, this invention has been realized. The invention has an object to provide an electrical connector which complies with requirements for narrower pitches of conductors, for miniaturization, and for reduced overall height of the connector. The connectors are capable of sufficiently holding electrical connections with excellent durability against accidental forces when being fitted together and are also capable of providing power supply connections without using a plural number of terminals. 
     The object of the invention can be accomplished by the electrical connector as stated in claim  1  for connecting substrates. The connector includes a plug connector and a receptacle connector to be detachably fitted with each other. The receptacle connector includes a plurality of receptacle contacts and a block for arranging and holding said receptacle contacts. The receptacle contacts each have a first contact portion adapted to contact a mating contact, a first fixed portion to be fixed to said block, and a first connection portion to be connected to one of said substrates. The plug connector includes a plurality of plug contacts and a housing for arranging and holding said plug contacts. The plug contacts each have a second contact portion adapted to contact said receptacle contact, a second fixed portion to be fixed to said housing, and a second connection portion to be connected to the other of said substrates. Said plug connector and said receptacle connector are provided with a first fixture and a second fixture each arranged on at least one end in the longitudinal direction of the respective connector. Said first fixture and said second fixture each have connection portions to be connected to said substrate of the respective connector. One of said first and second fixtures is provided with at least three engaging portions, and the other of said fixtures is provided with at least three anchoring portions, respectively. Said engaging portions and said anchoring portions are adapted to engage each other. At least one set of said engaging and anchoring portions engaged with each other is caused to be in electrical continuity, thereby providing power supply contacts. 
     The electrical connector claimed in claim  2  is constructed such that said engaging portions and said anchoring portions are provided at three locations on said first and second fixtures at the center and at both ends in the width direction of the first and second fixtures, respectively. 
     The electrical connector claimed in claim  3  is constructed such that said first fixture is substantially in the form of a plate-shaped piece and comprises, as said engaging portions, second engaging portions on both sides projecting into the width directions of said first fixture. A first engaging portion projects into a fitting opening of said connector and is located on an elastic piece formed by folding back a part of said first fixture at the center in the width direction of said first fixture. Said second fixture is substantially in the form of an inverted U-shape. The second fixture comprises, as said anchoring portions, second anchoring portions corresponding to said second engaging portions, and is located on plate-shaped pieces folded back into substantially U-shapes on both ends in the width direction of said second fixture. A first anchoring portion is formed by folding back a part of said second fixture at the center in the width direction of said second fixture. 
     The electrical connector claimed in claim  4  is constructed such that the first engaging portion of said first fixture is formed as a protrusion, and said second engaging portions are formed as projecting portions projecting outwardly. The first anchoring portion of said second fixture is formed as a plate-shaped portion having a substantially U-shaped cross-section adapted to engage said protrusion, and said second anchoring portions are formed as recesses adapted to accommodate said projecting portions, respectively. 
     The electrical connector claimed in claim  5  is constructed such that the first engaging portion of said first fixture and the second anchoring portions of said second fixture each have an elasticity. 
     As can be seen from the above descriptions, the electrical connector according to the invention can provide the following significant functions and effects: 
     (1) The electrical connector for connecting substrates includes a plug connector and a receptacle connector to be detachably fitted with each other. Said receptacle connector includes a plurality of receptacle contacts and a block for arranging and holding said receptacle contacts. Said receptacle contacts each have a first contact portion adapted to contact a mating contact, a first fixed portion to be fixed to said block, and a first connection portion to be connected to one of said substrates. Said plug connector includes a plurality of plug contacts and a housing for arranging and holding said plug contacts. Said plug contacts each have a second contact portion adapted to contact said receptacle contact, a second fixed portion to be fixed to said housing. A second connection portion to be connected to the other of said substrates claimed in claim  1  is constructed such that said plug connector and said receptacle connectors are provided with a first fixture and a second fixture each arranged on at least one end in the longitudinal direction of the respective connector. Said first fixture and said second fixture each have connection portions to be connected to said substrate of the respective connector. One of said first and second fixtures is provided with at least three engaging portions, and the other of said fixtures is provided with at least three anchoring portions, respectively. Said engaging portions and said anchoring portions are adapted to engage each other, and at least one set of said engaging and anchoring portions engaged with each other is caused to be in electrical continuity, thereby using them as power supply contacts. Therefore, the electrical connector according to the invention can achieve narrower pitches of conductors and miniaturization and reduced overall height of the connector, and can ensure stable electrical connections because of engagements of the fixtures at three locations even while being subjected to accidental forces when being fitted. The electrical connector can provide a stable power supply connection by causing at least one set of the engaging portion of the fixtures to be in electrical continuity without using a number of terminals. 
     (2) The electrical connector claimed in claim  2  is constructed such that said engaging portions and said anchoring portions are provided at three locations on said first and second fixtures at the center and at both ends in the width direction of the first and second fixtures, respectively. Accordingly, the electrical connector according to the invention claimed in claim  2  can achieve narrower pitches of conductors and miniaturization and reduced overall height of the connector, and can ensure stable electrical connections because of engagements of the fixtures at three locations even if being subjected to accidental forces when being fitted. The electrical connector can utilize a stable power supply connector by causing at least one set of the engaging portion of the fixtures to be in electrical continuity without using a number of terminals. Since the first engaging portions and the first anchoring portions of the first and second fixtures are located substantially at the center in the width direction of the fixture or the connectors, even if accidental forces acting on the connectors in the longitudinal direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply unit. Further, since the second engaging portions and the second anchoring portions of the first and second fixtures are located substantially on both ends in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the width direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply unit. 
     (3) The electrical connector claimed in claim  3  is constructed such that said first fixture is substantially in the form of a plate-shaped piece. The first fixture comprises, as said engaging portions, second engaging portions on both sides projecting into width directions of said first fixture. A first engaging portion projects into a fitting opening of said connector and is located on an elastic piece formed by folding back a part of said first fixture at the center in the width direction of said first fixture, and that said second fixture is substantially in the form of an inverted U-shape. The second fixture comprises, as said anchoring portions, second anchoring portions corresponding to said second engaging portions and located on plate-shaped pieces folded back into substantially U-shapes on both ends in the width direction of said second fixture. A first anchoring portion is formed by folding back a part of said second fixture at the center in the width direction of said second fixture. Consequently, the electrical connector according to the invention claimed in claim  3  can achieve narrower pitches of conductors and miniaturization and reduced overall height of the connector, and can ensure stable electrical connections because of engagements of the fixtures at three locations even if being subjected to accidental forces when being fitted. The electrical connector can provide a stable power supply connection by causing at least one set of the engaging portion of the fixtures to be in electrical continuity without using a number of terminals. Since the first engaging portions and the first anchoring portions of the first and second fixtures are located substantially at the center in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the longitudinal direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used also as a power supply connector. Further, since the second engaging portions and the second anchoring portions of the first and second fixtures are located substantially on both ends in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the width direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply connector. 
     (4) The electrical connector claimed in claim  4  is constructed such that the first engaging portion of said first fixture is formed as a protrusion. Said second engaging portions are formed as projecting portions projecting outwardly. The first anchoring portion of said second fixture is formed as a plate-shaped portion having a substantially U-shaped cross-section adapted to engage said protrusion. Said second anchoring portions are formed as recesses adapted to accommodate said projecting portions, respectively. Accordingly, the electrical connector according to the invention claimed in claim  4  can achieve narrower pitches of conductors and miniaturization and reduced overall height of the connector, and can ensure stable electrical connections because of engagements of the fixtures at three locations even if being subjected to accidental forces when being fitted. The electrical connector can also provide a stable power supply connection by causing at least one set of the engaging portion of the fixtures to be in electrical continuity without using a number of terminals and contacts. Since the first engaging portions and the first anchoring portions of the first and second fixtures are located substantially at the center in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the longitudinal direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply connector. Further, since the second engaging portions and the second anchoring portions of the first and second fixtures are located substantially on both ends in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the width direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply connector as well. 
     (5) The electrical connector claimed in claim  5  is constructed such that the first engaging portion of said first fixture and the second anchoring portions of said second fixtures each have an elasticity. Therefore, the electrical connector according to the invention claimed in claim  5  can achieve narrower pitches of conductors and miniaturization and reduced overall height of the connector, and can ensure stable electrical connections because of engagements of the fixtures at three locations even if being subjected to accidental forces when being fitted. The electrical connector can be utilized as a stable power supply connector by causing at least one set of the engaging portion of the fixtures to be in electrical continuity without using a number of terminals or contacts. Since the first engaging portions and the first anchoring portions of the first and second fixtures are located substantially at the center in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the longitudinal direction are increased, the engagements of these engaging and anchoring portions do not disengage. Thus, such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply connector. Further, since the second engaging portions and the second anchoring portions of the first and second fixtures are located substantially on both ends in the width direction of the fixtures or the connectors, even if accidental forces acting on the connectors in the width direction are increased, the engagements of these engaging and anchoring portions do not disengage, and such a rigid engagement portion is caused to be in electrical continuity, thereby enabling the engagement portion to be used as a power supply connector. 
     The invention will be more fully understood by referring to the following detailed specification and claims taken in connection with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a plug connector viewed from its fitting opening; 
         FIG. 1B  is a perspective view of a receptacle connector viewed from its fitting portion; 
         FIG. 2A  is a perspective view of the plug and receptacle connectors fitted with each other; 
         FIG. 2B  is a cross-sectional view of the fitted plug and receptacle connectors taken along some contacts; 
         FIG. 2C  is a cross-sectional view of the fitted plug and receptacle connectors taken along fixtures; 
         FIG. 3A  is a perspective view of a plug contact; 
         FIG. 3B  is a perspective view of a receptacle contact; 
         FIG. 4A  is a perspective view of a housing of the plug connector; 
         FIG. 4B  is a perspective view of a block of the receptacle connector; 
         FIG. 5A  is a perspective view of a first fixture; 
         FIG. 5B  is a perspective view of a second fixture; 
         FIG. 5C  is a perspective view of the first and second fixtures engaging each other at both ends in the longitudinal direction of the electrical connector; 
         FIG. 6A  is a cross-sectional view of the plug connector taken along plug contacts; and 
         FIG. 6B  is a cross-sectional view of the receptacle connector taken along receptacle contacts. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The subject features of the invention lie in an electrical connector  10  for connecting substrates, including a receptacle connector  20  and a plug connector  50  to be detachably fitted with each other. Said receptacle connector  20  includes a plurality of receptacle contacts  24  and a block  22  for arranging and holding said receptacle contacts  24 . Said receptacle contacts  24  each have a first contact portion  26  adapted to contact a mating contact, a first fixed portion  28  to be fixed to the block  22 , and a first connection portion  30  to be connected to one of the substrates. Said plug connector  50  includes a plurality of plug contacts  56  and a housing  52  for arranging and holding said plug contacts  56 . Said plug contacts  56  each have a second contact portion  58  adapted to contact said receptacle contact  24 , a second fixed portion  60  to be fixed to said housing  52 , and a second connection portion  64  to be connected to the other of the substrates. The receptacle and plug connectors  20  and  50  are provided with a first fixture  54  and a second fixture  25 , respectively, each arranged on at least one end in the longitudinal direction of the respective connector. Each has connection portions  74 ,  44  to be connected to the substrate of the connector. Said first and second fixtures are provided with at least three engaging portions  76  and  77  and at least three anchoring portions  46  and  48 , respectively. Said engaging portions  76  and  77  and said anchoring portions  46  and  48  are adapted to engage each other. At least one set of said engaging and anchoring portions engaged each other is caused to be in electrical continuity, thereby using it as a power supply contact. 
     In other words, said first fixture  54  and said second fixture  25  are arranged on at least one ends in the longitudinal direction of the receptacle and plug connectors  20  and  50 , respectively, so that the respective fixtures  54  and  25  are locked (engaged) together at three locations and at least one locked portion is caused to be into electrical continuity, thereby using the locked portion as a power supply contact. 
     One embodiment of the electrical connector according to the invention will be explained with reference to drawings.  FIG. 1A  is a perspective view of a plug connector viewed from its fitting opening, and  FIG. 1B  is a perspective view of a receptacle connector viewed from its fitting portion.  FIG. 2A  is a perspective view of the plug and receptacle connectors fitted with each other.  FIG. 2B  is a cross-sectional view of the fitted plug and receptacle connectors taken along some contacts.  FIG. 2C  is a cross-sectional view of the fitted plug and receptacle connectors taken along fixtures.  FIG. 3A  is a perspective view of a plug contact, and  FIG. 3B  is a perspective view of a receptacle contact.  FIG. 4A  is a perspective view of a housing of the plug connector, while  FIG. 4B  is a perspective view of a block of the receptacle connector.  FIG. 5A  is a perspective view of a first fixture, while  FIG. 5B  is a perspective view of a second fixture, and  FIG. 5C  is a perspective view of the first and second fixtures engaging each other at both ends in the longitudinal direction of the electrical connector.  FIG. 6A  is a cross-sectional view of the plug connector taken along plug contacts, while  FIG. 6B  is a cross-sectional view of the receptacle connector taken along receptacle contacts. 
     The electrical connector  10  according to the invention comprises a plug connector  50  and a receptacle connector  20 . Each of the connectors  50  and  20  mainly comprises contacts  56 ,  24 , a plastic insulator, and fixtures  54 ,  25 . 
     First, the receptacle connector  20  will be explained. Said receptacle connector  20  mainly comprises a block  22 , receptacle contacts  24 , and second fixtures  25 . 
     First, the receptacle contacts  24  will be explained. The receptacle contacts  24  are made of a metal and formed by means of the press-working of a known technique. Preferred metals from which to form the receptacle contacts  24  include brass, beryllium copper, phosphor bronze and the like which comply with the requirements as to springiness, electric conductivity, and the like. The receptacle contact  24  mainly comprises a first contact portion  26  adapted to contact a plug contact  56 , a first fixed portion  28  to be fixed to said block  22 , a first connection portion  30  to be connected to a substrate, and an elastic portion  32  located between said first contact portion  26  and said first fixed portion  28 . 
     As shown in  FIG. 3B , the respective portions of the receptacle contact  24  are located in the order of the first contact portion  26 , the elastic portion  32 , the first fixed portion  28 , and the first connection portion  30 . The respective portions will now be explained. First, the first contact portion  26  is adapted to contact the second contact portion  58  of a plug contact  56 . Said first contact portion  26  is substantially in the form of a plate piece and is curved so that the first contact portions  26  contacts the second contact portion  58  of the plug contact  56  in a line contact at one location. The first contact portion  26  need only be able to contact the second contact portion  58  of said plug contact  56  and may be suitably designed in consideration of contact stability, space-saving and a reduced overall height of the electrical connector  10  upon being fitted, workability and the like. 
     Said elastic portion  32  is provided with at least one serpentine portion or tortuous portion in order to achieve a miniaturization of the connector and stable contact between the receptacle and plug contacts  24  and  56  by pushing said plug connector  50  with the contact pressure obtained by the elasticity of the elastic portion  32 . In the illustrated embodiment, the elastic portion  32  of the receptacle contact  24  has one serpentine portion. The elastic portion  32  is positioned substantially at the upper portion of the block  22  corresponding to the height of the block  22 . The number of serpentine portions may be arbitrary insofar as the plug connector  50  is pushed with the contact pressure to obtain the stable contact, and may be suitably designed taking into account the contact pressure, space-saving, and reduced overall height of the fitted electrical connector  10 , workability, and the like. The radius of curvature of the serpentine portion of the elastic portion  32  may be suitably designed in consideration of the space-saving and reduced overall height of the fitted electrical connector  10 , workability, and the like. 
     The first fixed portion  28  of the receptacle contact  24  is adapted to be held in a first inserting hole  34  of the block  22 . In the illustrated embodiment, the first fixed portion is inserted into the first inserting hole  34  by press-fitting. However, any methods other than the press-fitting may be used so long as the receptacle contacts can be firmly held, and these methods may be selected in consideration of the miniaturization of the connector, strength, the holding force, and the like. 
     Said first connection portion  30  of the receptacle contact  24  is adapted to be connected to a substrate. The shape (or type) of the first connection portion  30  is a surface mounting type (SMT) in the illustrated embodiment, but the shape (type) is arbitrary so long as it can be connected to the substrate. For example, a dip type may be used. 
     Said block  22  will now be explained. Said block  22  comprises two first side walls  36 , a first bottom wall  38 , first flanges  40 , and a fitting portion  7 , and is substantially in the form of a hexahedron as a whole. Said block  22  is formed from an electrically insulating plastic material by means of the injection molding of a known technique. The materials for the block  22  may be suitably selected in consideration of dimensional stability, workability, manufacturing cost, and the like and generally include polybutylene terephthalate (PBT), polyamide (66PA or 46PA), liquid crystal polymer (LCP), polycarbonate (PC), polyphenylene sulfide (PPS), and the like and combinations thereof. The two first side walls  36  of the block  22  are formed with the first inserting holes  34  into which a required number of the receptacle contacts  24  are installed and fixed, respectively, by means of any one of press-fitting, hooking (lancing), welding, and the like. In the illustrated embodiment, the receptacle contacts  24  are fitted in the first inserting holes  34  by press-fitting. 
     The fitting portion  7  of said block  22  is formed to be surrounded by the two first side walls  36 , the first bottom wall  38 , and the first flanges  40  and is adapted to be fitted in a fitting opening  5  of said plug connector  50 . Said fitting portion  7  need only be fitted in the fitting opening  5  of said plug connector  50  as a mating connector. The size and shape of the fitting portion  7  may be suitably designed so as to be commensurate with the plug connector and in consideration of the contact stability, miniaturization of the connector, workability, and the like. 
     Said first flanges  40  are each formed with a third insertion hole  35  into which the second fixture  25  is inserted and fixed by means of any one of press-fitting, hooking (lancing), welding, and the like. In the illustrated embodiment, the second fixtures  25  are fixed in the third insertion holes  35  by press-fitting. 
     The second fixtures  25  will then be explained, which form an important aspect of the invention. The second fixtures  25  are made of a metal and formed by means of the press-working of a known technique. Preferred metals from which to form the second fixtures  25  include brass, beryllium copper, phosphor bronze and the like which comply with the requirements as to springiness, electric conductivity, and the like. Said second fixture  25  mainly comprises first and second anchoring portions  46  and  48  positioned in at least three locations and adapted to engage the first fixture  54 , third fixed portions  42  to be fixed to said block  22 , and third connection portions  44  to be connected to the substrate. 
     Said second fixtures  25  are arranged at both ends in the longitudinal direction of the receptacle connector  20 , respectively, to achieve balancing. Said second fixture  25  is substantially in the form of an inverted U-shape, and includes on both sides plate-shaped pieces  49 . Each of the plate-shaped pieces  49  is substantially U-shaped by folding back that portion itself and is formed with the second anchoring portion  48  which corresponds to a second engaging portion  77  of the first fixture  54 . The second fixture  25  further includes the first anchoring portion  46  formed by folding back that portion itself at the center of the width of the second fixture  25 . The center of the width of the second fixture  25  substantially corresponds to the center of the width of the receptacle connector  20 . The first anchoring portion  46  of the second fixture  25  is formed as a plate-shaped portion  461  having a U-shaped cross-section adapted to engage a protrusion  761  of the first fixture  54 . Said second anchoring portions  48  are formed as recesses  481  for receiving projecting portions  771  of the first fixture  54 , respectively. The second anchoring portions  48  of said second fixture  25  have an elasticity. 
     The shapes and sizes of said plate-shaped portion  461  (the first anchoring portion  46 ) and said recesses  481  (the second anchoring portions  48 ) may be any of various ones so long as they can engage the protrusion  761  (the first engaging portion  76 ) and the projecting portions  771  (the second engaging portions  77 ) of said first fixture  54 , respectively, to obtain stable holding force and to achieve electrical continuity. They may be suitably designed taking into account the electrical continuity, workability, holding forces, miniaturization of the connector, and the like. 
     Said third fixed portions  42  are held in the third insertion holes  35  of said block  22 . The third fixed portions  42  are inserted and held in the third insertion holes  35  by press-fitting in the illustrated embodiment. However, any methods other than press-fitting may be used insofar as the third fixed portions  42  can be firmly fixed. These methods may be suitably selected in consideration of the miniaturization of the connector, strength, holding forces, and the like. 
     Said third connection portions  44  are to be connected to the substrate. The shape (type) of the third connection portions may be any shape (type) insofar as they can be connected to the substrate. The surface mounting type (SMT) is employed for the third connection portions  44  in the illustrated embodiment, although, for example, a dip type may be used. 
     The plug connector  50  will then be explained. Said plug connector  50  mainly comprise a housing  52 , plug contacts  56 , and first fixtures  54 . 
     The plug contacts  56  will now be explained. The plug contacts  56  are made of a metal and formed by means of the press-working of the known technique. Preferred metals from which to form the plug contacts  56  include brass, beryllium copper, phosphor bronze and the like which comply with the requirements as to springiness, electric conductivity, and the like. Said plug contact  56  mainly comprises a second contact portion  58  adapted to contact the receptacle contact  24 , a second fixed portion  60  to be fixed to said housing  52 , and a second connection portion  64  to be connected to a substrate. 
     As shown in  FIG. 3A , the respective portions of the plug contact  56  are located in the order of the second contact portion  58 , the second fixed portion  60 , and the second connection portion  64 . The respective portions will be explained hereinafter. First, the second contact portion  58  is adapted to contact the first contact portion  26  of the receptacle contact  24 . The second contact portion  58  need only be able to contact the first contact portion  26  of said receptacle contact  24  and may be suitably designed in consideration of contact stability, space-saving, and a reduced overall height of the electrical connector  10  upon being fitted, workability, and the like. In the embodiment described, however, said second contact portion  58  may be provided in the flat portion of its substantially plate-shaped portion with a recess (not shown) in order to achieve stable removal force and click response which indicates a completion of the fitting. The shape and size of the recess may be suitably designed taking into account the functions described above, strength, contact stability, workability and the like. 
     Said second contact portion  58  of said plug contact  56  is formed in a manner that it is folded back outwardly of a second wall  66  of the housing  52 . The result is that the second contact portion  58  becomes easy to contact said receptacle contact  24 . 
     Said second fixed portion  60  of the plug contact  56  is adapted to be held in one of second inserting holes  78  of the housing  52 . In the illustrated embodiment, the second fixed portion  60  is inserted and held in the second inserting hole  78  by press-fitting. However, any method other than the press-fitting may be used so long as the plug contact  56  can be firmly held, and these methods may be selected in consideration of the miniaturization of the connector, strength, the holding force, and the like. 
     Said second connection portion  64  of the plug contact  56  is to be connected to a substrate. The shape (or type) of the second connection portion  64  is a surface mounting type (SMT) in the illustrated embodiment, but the shape (type) is arbitrary so long as it can be connected to the substrate. For example, a dip type may be used. 
     Said housing  52  will then be explained. Said housing  52  is formed by the two second side walls  66 , second flanges  70  and a second bottom wall  68  to form a substantial hexahedral shape. Said housing  52  is formed from an electrically insulating plastic material by means of the injection molding of the known technique. The materials for the housing  52  may be suitably selected in consideration of dimensional stability, workability, manufacturing cost, and the like and generally include polybutylene terephthalate (PBT), polyamide (66PA or 46PA), liquid crystal polymer (LCP), polycarbonate (PC), polyphenylene sulfide (PPS), and the like, and combinations thereof. The two second side walls  66  of the housing  52  are formed with second inserting holes  78  into which a required number of the plug contacts  56  are installed and fixed, respectively, by one method of press-fitting, hooking (lancing), welding, and the like. The shape and size of said second inserting holes  78  may be suitably designed taking into account the size and shape of said plug contacts  56 , holding forces, and the like. 
     The two side walls  66 , the second flanges  70 , and the second bottom wall  68  form the fitting opening  5  into which the fitting portion  7  of said receptacle connector  20  is fitted. Said fitting opening  5  need only be fitted with the fitting portion  7  of said receptacle connector  20  as a mating connector. The size and shape of the fitting opening  5  may be suitably designed to be commensurate with said receptacle connector  20  and in consideration of contact stability, the miniaturization of the connector, workability, and the like. 
     The second flanges  70  are each formed with a fourth insertion hole  79  into which said first fixture  54  is fitted and fixed. The first fixtures  54  are fixed into the fourth insertion holes  79 , respectively, by means of one of press-fitting, hooking (lancing), welding, and the like. The first fixtures  54  are fixed into the fourth insertion holes  79  by press-fitting in the illustrated embodiment. 
     The first fixtures  54  will now be explained, which form the important aspect of the invention. The first fixtures  54  are made of a metal and formed by means of the press-working of the known technique. Preferred metals from which to form the first fixtures  54  include brass, beryllium copper, phosphor bronze and the like which comply with the requirements as to springiness, electric conductivity, and the like. Said first fixture  54  mainly comprises at least three engaging portions  76  and  77  adapted to engage the three anchoring portions of the second fixture  25 , respectively, fourth fixed portions  72  to be fixed to said housing  52 , and fourth connection portions  74  to be fixed to the substrate. 
     Said first fixtures  54  are arranged at both the ends in the longitudinal direction of the plug connector  50 , respectively, in view of balancing. Said first fixture  54  is substantially in the form of a plate-shaped piece, and includes the second engaging portions  77  projecting on both sides into the width directions of the plug connector  50 . The first fixture  54  further includes at its center an elastic piece  80  formed by folding back that portion itself, the elastic piece  80  being provided with the first engaging portion  76  projecting into the fitting opening  5 . The center of the width of the first fixture  54  substantially corresponds to the center of the width of the plug connector  50 . The first engaging portion  76  of said first fixture  54  is formed as a protrusion  761 , while the second engaging portions  76  are formed as projecting portions  771  outwardly projecting. The first engaging portion  76  of said first fixture  54  has an elasticity. 
     The shapes and sizes of said protrusion  761  (said first engaging portion  76 ) and said projecting portions  771  (said second engaging portions  77 ) may be any of various ones so long as they can engage the plate-shaped portion  461  (said first anchoring portion  46 ) and the recesses  481  (said second anchoring portions  48 ), respectively, to obtain stable holding force and to achieve electrical continuity. They may be suitably designed in consideration of the electrical continuity, workability, holding forces, miniaturization of the connector, and the like. 
     Said fourth fixed portions  72  of the first fixtures  54  are held in the fourth inserting holes  79  of said housing  52 . The fourth fixed portions  72  are inserted and held in the fourth inserting holes  79  by press-fitting in the illustrated embodiment. However, any methods other than press-fitting may be used insofar as the fourth fixed portions  72  can be firmly fixed. These methods may be suitably selected in consideration of the miniaturization of the connector, strength, holding forces, and the like. 
     Said fourth connection portions  74  are to be connected to the substrate. The shape (type) of the fourth connection portions  74  may be any shape (type) so long as they can be connected to the substrate. The surface mounting type (SMT) is employed for the fourth connection portions  74  in the illustrated embodiment, although, for example, a dip type may be used. 
     Although the first fixtures  54  each having the engaging portions and the second fixtures  25  each having the anchoring portions are shown and explained in the embodiment, it is to be understood that the first fixtures  54  may be provided with anchoring portions and the second fixtures  25  may be provided with engaging portions. 
     Examples of applications of the present invention are electrical connectors for use with electric and electronic appliances such as cell-phones, small type personal computers, and the like, and more particularly electrical connectors capable of sufficiently withstanding accidental external forces and having the fixtures which are usable also as power supply contacts other than their inherent function of fixing the connectors. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.