Patent Publication Number: US-6220894-B1

Title: Electric connector and electric connecting unit featuring such a connector

Description:
The present invention relates to an electric connector, in particular for a circuit for activating a vehicle air-bag device, and to an electric connecting unit defined by connection of said connector to a complementary connector in an assembly direction. 
     Electric connectors of the above type are known to comprise an insulating casing defining a number of cavities having axes parallel to said assembly direction and for housing respective electric terminals, which are connected to respective electric cables and retained inside the cavities by main retaining means; and, for each cavity, the main retaining means comprise a retaining seat formed in the respective terminal, and an elastically deformable latch member forming part of the casing and which clicks onto the seat. 
     Such connectors also comprise auxiliary retaining means for determining correct insertion, and further ensuring retention, of the terminals inside the respective cavities. 
     The auxiliary retaining means normally comprise a movable member which clicks onto the casing and may either be hinged to and integral with the casing, or defined by a separate member. Whichever the case, the movable member only clicks onto the casing when all the terminals are inserted correctly and locked inside the respective cavities by the respective latch members. Conversely, if any one of the terminals is not properly or fully inserted, the main retaining means remain deformed, thus preventing assembly of the movable member and so enabling the fault to be detected. 
     Known connectors of the type briefly described above involve several drawbacks. In the event one of the terminals is not inserted fully inside the respective cavity, the movable member may be forced into the connecting position despite interference with the main retaining means, thus resulting, for example, in breakage or deformation of the contacting parts; and the connector so assembled may be connected to a complementary connector. In such cases, improper assembly of the terminal may go undetected during testing, on account, for example, of the terminal being so positioned as determine an albeit precarious electric contact which, in applications in which the connector is subjected to vibration, as on a vehicle, is bound to fail eventually, with all the obvious consequences this entails. 
     It is an object of the present invention to provide a straightforward, reliable, low-cost electric connector designed to eliminate the aforementioned drawback typically associated with known connectors. 
     According to the present invention, there is provided a connector as defined in claim  1 . 
     The present invention also relates to an electric connecting unit as defined in claim  8 . 
    
    
     A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
     FIG. 1 shows a view in perspective of an electric connecting unit in accordance with the present invention in course of assembly; 
     FIG. 2 shows a longitudinal section of the FIG. 1 unit; 
     FIG. 3 shows a longitudinal section of the FIG. 1 unit fully assembled; 
     FIG. 4 shows a section along line IV—IV in FIG. 2; 
     FIG. 5 shows a section along line V—V in FIG. 3; 
     FIG. 6 shows a view in perspective of a first connector of the FIG. 1 unit; 
     FIG. 7 shows a view in perspective of a second connector of the FIG. 1 unit. 
    
    
     With reference to FIGS. 1 to  5 , number  1  indicates as a whole an electric connecting unit comprising two electric connectors  2 ,  3  connectable to each other in a longitudinal assembly direction A, and a device  4  for click-on connecting connectors  2 ,  3  in a final assembly position. 
     It should be stressed that the terms “top”, “bottom”, “front”, “rear” and similar used in the following description are in now way limiting, and are used solely for the sake of clarity with reference to the position of unit  1  shown in FIGS. 1 to  5 . 
     Connector  2  (FIGS. 1 to  6 ) comprises a substantially parallelepiped-shaped insulating casing  5  defining a number of—in the example shown, three—longitudinal through cavities  6  arranged side by side in a direction B perpendicular to direction A, and for housing respective female electric terminals  7  connected to respective electric cables  8 . Connector  2  also comprises main retaining means  9  for retaining each terminal  7  in a correct insertion position inside respective cavity  6 ; and auxiliary retaining means  10  for determining correct insertion of terminals  7  inside cavities  6  and preventing withdrawal of the terminals. 
     Casing  5  comprises a plate  11  (for the purpose explained later on) projecting frontwards—substantially as an extension of a top wall  12  of casing  5  parallel to directions A and B—and having, on the outside, on the opposite side to cavities  6 , two ribs  13  parallel to direction A. 
     Connector  3  (FIGS. 1 to  5  and FIG. 7) comprises an insulating casing  14  having a substantially parallelepiped-shaped rear portion  15  defining a number of—in the example shown, three—longitudinal cavities  16  for housing respective male electric terminals  17  connected to respective electric cables  18  and for connection to female terminals  7  of connector  2 , and a hollow, substantially parallelepiped-shaped front portion  19  defining a compartment  20  for housing connector  2  and which is complementary in shape to casing  5  and communicates with cavities  16 . Like connector  2 , connector  3  also comprises main retaining means  25  for retaining each terminal  17  in a correct insertion position inside respective cavity  16 ; and auxiliary retaining means  26  for determining correct insertion of terminals  17  inside cavities  16  and preventing withdrawal of the terminals. 
     More specifically, portion  19  projects outwards on opposite sides of portion  15  in a direction C perpendicular to directions A and B, anci is connected to portion  15  by two walls  27  perpendicular to direction A and forming an extension of an end wall of compartment  20 . One of walls  27  has a shaped through opening  28  engaged, in the final assembly position of connectors  2 ,  3 , by plate  11 , which projects from compartment  20  and is positioned contacting a top wall  29  of portion  15 . Inside compartment  20 , portion  19  also comprises two grooves  30  parallel to direction A and which are engaged in sliding manner by ribs  13  of plate  11  when assembling connectors  2  and  3 , so as to define a guide for plate  11 . 
     With particular reference to FIGS. 1,  6  and  7 , device  4  comprises a male member  31  located close to a front opening of portion  19  and projecting integrally inwards of compartment  20  of casing,  14  from a top longitudinal wall  32  of portion  19 ; and an elastic member  33 , which projects longitudinally from an outer face of wall  12  of casing  5 , has a seat  34  for retaining male member  31 , and is flexible parallel to direction C to permit release of connectors  2 ,  3 . When connecting connectors  2  and  3 , male member  31  cooperates in sliding manner, in direction A, with seat  34  to engage seat  34  in a position corresponding to the final assembly position of connectors  2 ,  3 . 
     More specifically, male member  31  is defined by a tooth comprising a wedge-shaped main portion  35 , which in turn is defined by opposite substantially longitudinal, convex lateral surfaces, and, sectioned in a plane perpendicular to direction C, is substantially ogival in shape, tapering towards a pointed front end facing the front opening of portion  19 . At the opposite end, male member  31  comprises two projections  36  projecting laterally from portion  35  and defining, towards the pointed end of portion  35 , respective shoulders  37  substantially crosswise to direction A. More specifically, shoulders  37  slope slightly with respect to a plane perpendicular to direction A so as to converge towards the pointed end of portion  35 . At the end opposite the pointed end, male member  31  is defined by two surfaces  41  substantially parallel to shoulders  37  and forming an obtuse dihedral angle. 
     Elastic member  33  comprises two substantially parallel longitudinal arms  38 , which are symmetrical with respect to an intermediate plane π of connector  2 , form extensions of ribs  13 , and each have one end integral with a front transverse edge of wall  12 . Respective free ends of arms  38  are connected integrally by a cross member  39  projecting outwards from casing  14  of connector  3  in the final assembly position of connectors  2 ,  3 , and which is pressed manually in direction C towards wall  12  to permit release of connectors  2 ,  3 . 
     Arms  38  comprise respective intermediate projections  40  symmetrical with respect to plane π, extending towards each other, and substantially in the form of right trapeziums with the oblique sides facing each other. Seat  34  has an axis parallel to direction A and lying in plane π, and is defined by projections  40  and by respective portions of arms  38  extending between projections  40  and cross member  39 . 
     Arms  38  are flexible in a plane substantially perpendicular to direction C to permit insertion of male ember  31  inside seat  34 . 
     More specifically, each projection  4 ) is defined by a lateral first surface  45  perpendicular to direction A and facing plate  11 ; by a lateral second surface  46  facing cross member  39  and sloping at the same angle as respective surface  41  of male member  31 ; and by a substantially longitudinal third surface  47  interposed between surfaces  45  and  46 , sloping with respect to direction A, and defining a section of seat  34  increasing from surface  45  to surface  46   
     Surfaces  45  define a front opening of seat  34  and a temporary stop for shoulders  37  of male member  31  when connecting connectors  2 ,  3 , so that the force required to connect connectors  2 ,  3  must be increased to a threshold value sufficient to click shoulders  37  past surfaces  45  and enable male member  31  to assume the engaged position in which surfaces  41  rest against surfaces  46  of seat  34 . 
     Surfaces  47  are so formed as to exert elastic thrust on male member  31  to bring male member  31  irreversibly into the engaged position is projections  36  of male member  31  click past surfaces  45  when connecting connectors  2 ,  3 . 
     With reference to FIGS. 2 to  5 , each terminal  7  of connector  2  comprises a box-shaped front contact portion  48 ; a rear portion  49  for connection to respective electric cable  8 ; and an intermediate portion  50  extending between portions  48  and  49 . 
     Each terminal  7  is inserted inside respective cavity  6  through a rear opening  51  of the cavity, from which cable  8  projects, and is positioned with contact portion  48  facing a front opening  52  of cavity  6 . 
     Main retaining means  9  comprise, for each terminal  7 , a retaining seat  53  formed in intermediate portion  50  of terminal  7 ; and an elastic lance  54 , which projects inside respective cavity  6 , towards front opening  52 , from a bottom wall  42  of casing  5  parallel to wall  12 , and clicks onto seat  53  by means of a Respective tooth  55  to retain terminal  7  in the correct insertion position inside cavity  6 . 
     Each lance  54  interacts with respective terminal  7  so as to flex, parallel to director C, between an undeformed configuration corresponding to a position in which tooth  55  engages respective seat  53  and terminal  7  is inserted correctly inside respective cavity  6 , and a deformed configuration in which the lance is flexed away from the axis of cavity  6 . 
     Auxiliary retaining means  10  comprise a hatch-type movable member  56  integral with and extending the full width of casing  5 , and hinged to a repair end of wall  42  to rotate between an open position permitting insertion of terminals  7  inside respective cavities  6 , and a closed position, clicked onto casing  5 , to prevent withdrawal of terminals  7  from respective cavities  6 . 
     More specifically, movable member  55 , viewed from the side, is substantially L-shaped, and comprises a substantially flat base portion  57  hinged to wall  42  and having, on the outside, two parallel longitudinal projections  58 ; and two pairs of arms  59 ,  60  projecting perpendicularly from portion  57  and defining a number of U-shaped through openings  61 . When movable member  56  is, in the closed position, portion  57  extends parallel to wall  42 , each arm  59  is located between a pair of adjacent cables  8 , and each arm  60  is located outwards of an end cable  8 , so that each opening  61  is engaged by a respective electric cable  8  and has a lateral edge facing connecting portion  49  of respective terminal  7  in direction A, which portion  49  projects radially with respect to cable  8 . When movable member  56  is in the closed position, the lateral edges of openings  61  therefore define respective stops for portions  49 , to prevent withdrawal of terminals  7  from respective cavities  6 . 
     Movable member  56  is clicked into the closed position on casing  5  by retaining teeth  64 —projecting from a rear end of wall  42 —clicking inside respective end seats  63  on arms  60 . 
     In the closed position of movable member  56 , projections  58  of portion  57  cooperate in sliding manner with a wall  32   a , opposite wall  32 , of compartment  20  to permit connection of connectors  2  and  3  and, in the event of incorrect insertion of at least one of terminals  7  inside respective cavity  6 , interfere with wall  32   a  to prevent connection of connectors  2  and  3 . More specifically, when any one of terminals  7  is inserted improperly inside respective cavity  6 , retaining teeth  64  are prevented from engaging seats  63  on arms  60  by portion  49  of terminal  7  interacting with the lateral edge of respective opening  61 . 
     With reference to FIGS. 2 to  5 , each terminal  17  of connector  3  comprises a box-shaped intermediate portion  66 ; a contact portion  67  projecting frontwards from portion  66  and which fits inside contact portion  48  of a respective female terminal  7 ; and a rear portion  68  for connection to respective electric cable  18 . 
     Each terminal  17  is inserted inside respective cavity  16  through a rear opening  69  of the cavity, from which cable  18  projects in use, and is positioned with contact portion  67  projecting axially inside compartment  20  through a front opening  70  of cavity  16 . 
     Main retaining means  25  comprise, for each terminal  17 , a retaining seat  71  formed in intermediate portion  66  of terminal  17 ; and an elastic lance  72 , which projects inside respective cavity  16  from wall  29  and parallel to direction A towards front opening  70 , and clicks onto seat  71  by means of a respective tooth  73  to retain terminal  17  in the correct insertion position inside cavity  16 . 
     Each lance  72  interacts with respective terminal  17  so as to flex, parallel to direction C, between an undeformed configuration corresponding to a position in which tooth  73  engages respective seat  71  and terminal  17  is inserted correctly inside respective cavity  16 , and a deformed configuration in which the lance is flexed away from the axis of cavity  16 . 
     According to the present invention, each lance  72  is located at a respective substantially rectangular through opening  74  in wall  29 , and comprises an end projection  75  extending on the opposite side to tooth  73  and movable with lance  72 —by virtue of the interaction between lance  72  and respective terminal  17 , and, hence, of the position assumed by terminal  17  inside respective cavity  16 —between two work positions respectively disabling and enabling connection of connectors  2  and  3 . More specifically, in the disabling position corresponding to the deformed configuration of lance  72 , projection  75  projects outwards of all  29  through respective opening  74  and interferes with the sliding movement of plate  11  of connector  2  along wall  29 ; whereas, in the enabling position corresponding to correct insertion of terminal  17  inside respective cavity  16  and to the undeformed configuration of lance  72 , projection  75  engages opening  74  and is aligned with the outer edge of opening  74  to enable plate  11  of connector  2  to slide along wall  29 . 
     More specifically, projection  75  of each lance  72  is substantially in the form of a right trapezium with the oblique side facing outwards of wall  29 ; and each lance  72  has a portion  65  connected to wall  29  on the opposite side of projection  75  to connector  2 , so that, in the disabling position of projection  75 , any attempt to force connection of connectors  2  and  3  results in plate  11  jamming against projection  75 , thus preventing attainment of the final assembly position. 
     As in connector  2 , auxiliary retaining means  26  comprise a hatch-type movable member  76  integral with and extending the full width of casing  14 , and hinged to a rear end of wall  29  to rotate between an open position permitting insertion of terminals  17  inside respective cavities  16 , and a closed position, clicked onto casing  14 , to prevent withdrawal of terminals  17  from respective cavities  16 . 
     More specifically, movable member  76 , viewed from the side, is substantially L-shaped, and comprises a substantially flat rectangular base port on  77  hinged to wall  29 ; and two pairs of arms  78 ,  79  projecting perpendicularly from portion  77  and defiling a number of U-shaped through openings  80 . When movable member  76  is in the closed position, portion  77  extends parallel to wall  29 , each arm  78  is located between a pair of adjacent cables  18 , and each arm  79  is located outwards of an end cable  18 , so that each opening  80  is engaged by a respective electric cable  18  and has a lateral edge facing connecting portion  68  of respective terminal  17  in direction A, which portion  68  projects radially with respect to cable  18 . When movable member  76  is in the closed position, the lateral edges of openings  80  therefore define respective stops for portions  68 , to prevent withdrawal of terminals  17  from respective cavities  16 . 
     Movable member  76  is clicked into the closed position on casing  14  by retaining teeth  83 —projecting from a rear end of a bottom wall  84 , parallel to wall  29 , of portion  15 —clicking inside respective end seats  82  on arms  79 . 
     Unit  1  is assembled by sliding connector  2  longitudinally in direction A inside portion  19  of connector  3 , with terminals  7 ,  17  first inserted inside respective cavities  6 ,  16  and retained by respective lances  54 ,  72 , and with movable members  56 ,  76  first clicked into the closed position on respective casings  5 ,  14  (FIGS. 1,  2  and  4 ). 
     If any one of terminals  7  is not inserted properly inside respective cavity  6 , the respective lance  54  is maintained by terminal  7  in the deformed configuration in which tooth  55  is disengaged from seat  53  and, on account of the lateral edge of respective opening  61  interacting with connecting portion  49  cf terminal  7 , teeth  64  are prevented from engaging seats  63  on arms  60 , thus preventing movable member  56  from being clicked into the closed position. In which case, portion  57  of movable member  56  is inclined with respect to wall  42 , and projections  58  interfere with wall  32   a  of compartment  20 , thus preventing connector of connectors  2  and  3 . 
     Conversely, if terminals  7  are all inserted correctly inside respective cavities  6 , i.e. with teeth  55  of lances  54  clicked inside seats  53 , the lateral edges of openings  61  fit behind portions  49  of terminals  7  and surround cables  8 , thus enabling movable member  56  to be clicked into the closed position wherein portion  57  extends parallel to wall  42 , and projections  58  cooperate in sliding manner with wall  32   a  inside compartment  20  to enable connection of connectors  2  and  3  (FIGS.  3  and  5 ). 
     If any one of terminals  17  is not inserted properly inside respective cavity  16 , the respective lance  72  is maintained by terminal  17  in the deformed configuration in which tooth  73  is disengaged from seat  71 , and projection  75  is in the disabling position projecting outwards of wall  29  through respective opening  74  and interfering with the sliding movement of plate  11  of connector  2  along wall  29 , thus preventing connection of connectors  2  and  3 . Moreover, on account of the lateral edge of respective opening  80  interacting with connecting portion  68  of the improperly inserted terminal  17 , teeth  83  are prevented from engaging seats  82  on arms  79 , thus preventing movable member  76  from being clicked into the closed position. 
     Conversely, if terminals  17  are all inserted correctly inside respective cavities  16 , i.e. with teeth  73  of lances  72  clicked inside seats  71 , projections  75  are in the enabling position engaging respective openings  74 , and are aligned with the outer edges of openings  74 , thus enabling plate  11  of connector  2  to slide along wall  29  and, hence, connection of connectors  2  and  3 . Moreover, in the above condition, the lateral edges of openings  80  fit behind portions  68  of terminals  17  and surround cables  18 , thus enabling movable member  76  to be clicked into the closed position (FIGS.  3  and  5 ). 
     As connector  2  is slid longitudinally in direction A inside compartment  20  of connector  3 , male member  31  is inserted inside seat  34  of elastic member  33 ; and, on account of portion  35  of male member  31  increasing in section towards projections  36 , the gradual insertion of male member  31  inside seat  34  elastically deforms arms  38 , which part in the plane perpendicular to direction C. At the initial connection stage, the elastic reaction of arms  38 —by virtue of the shape of male member  31 —is such as to repel connectors  2  and  3 , sc that, if any one of terminals  7  and/or  17  is not inserted properly inside respective cavity  6 ,  16  so that projections  58  of movable member  56  interfere with wall  32   a  of compartment  20  and/or projection  75  of respective lance  72  interferes with plate  11 , connectors  2  and  3  are immediately repelled in direction A in the opposite sense to that of assembly. 
     Upon shoulders  37  of male member  31  coming to rest against respective surfaces  45  of projections  40 , surfaces  45  temporarily arrest male member  31 , so that additional thrust is required to elastically part arms  38 , which are subjected to a transverse thrust component on account of the slope of shoulders  37  If the thrust applied exceeds a threshold value defined by the geometry of the contacting surfaces and by the characteristics of the material used, projections  36  of male member  31  click past surfaces  45  to click male member  31  into the engaged position corresponding to the final assembly position of connectors  2 ,  3 . 
     As projections  36  click past surfaces  45  and arms  38  begin returning to the undeformed position, surfaces  47 , by defining a portion of seat  34  increasing in section towards cross member  39 , exert thrust on male member  31  to push male member  31  irreversibly into the engaged position. 
     To disconnect connectors  2 ,  3 , cross member  39  is simply pushed in direction C to release surfaces  46  of projections  40  from respective surfaces  41  of male member  31 . 
     The advantages of unit  1  and connector  3  according to the present invention will be clear from the foregoing description. 
     In particular, if any one of terminals  17  of connector  3  is not inserted properly inside respective cavity  16 , the respective lance  72  is maintained by terminal  17  in the deformed configuration, and projection  75  projects outwards of wall  29  to prevent plate  11  of connector  2  from sliding along wall  29  and, hence, connection of electric connectors  2  and  3 . Consequently, even if movable member  76  is forced into the closed position, the presence of an improperly inserted terminal  17  would still be detected when assembling connector  3  to connector  2 . 
     The above characteristic, combined with movable member  56  of connector  2  comprising projections  58  for preventing insertion of connector  2  inside compartment  20  of connector  3  with movable member  56  in other than the closed position (terminals  7  not properly inserted), provides for extremely safe connection and a high degree of reliability of unit  1 . 
     Finally, the resistance offered by surfaces  45  of elastic member  33  to insertion of male member  31  inside seat  34  ensures expulsion of connector  2  from compartment  20  in the event one or more terminals  7 ,  17  are not properly inserted inside respective cavities  6 ,  16 , thus preventing forcing of the contacting parts. 
     Clearly, changes may be made to unit  1  as described herein with out, however, departing from the scope of the present invention.