ELECTRIC CONNECTOR

Abstract: An electric connector (1) presenting an insulating casing (2) with at least one axial cavity (3); an electric terminal (4) retained inside the cavity (3) by primary retaining means (5); and secondary retaining means (24) presenting a first movable element (25) which snaps on to the casing (2) to determine correct engagement and prevent disengagement of the primary retaining means (5) and the terminal (4); the secondary retaining means (24) also presenting a second movable element (37) interposed between the first movable element (25) and the terminal (4), and which the first movable element (25) causes to cooperate with and at least partly expel the terminal (4) from the cavity (3) in the event the primaryretaining means (5) fail to correctly engage the terminal (4).

Description: ELECTRIC CONNECTOR TECHNICAL FIELD The present invention relates to an electric connector, particularly of the type comprising an outer insulating casing defining at least one axial cavity, and an electric terminal housed and retained inside the cavity by primary retaining means. BACKGROUND ART Electric connectors of the aforementioned type are known, which comprise a secondary retaining device for ensuring retention of the terminals inside the respective cavities. The secondary retaining device normally comprises a movable element which snaps on to the outer casing, and which may either be hinged integrally with or formed separately from the casing. In either case, for the movable element to snap on to the casing, the terminal must first be inserted correctly inside the cavity and retained by the primary retaining means which normally consist of an elastically deformable lance forming part of the casing. In the event of incorrect or incomplete insertion of the terminal, this is detected by the primary retaining means being so deformed as to interfere with and prevent engagement of the movable element. Known connectors generally require testing apparatus, as disclosed in GB-A-2 170 962, DE-A-3 920 517 and DE-A-4 225 464, in order to detect assembly faults; however, even the use of such apparatus does not always prevent that connection faults arise. A drawback of known connectors of the type briefly described above is that, in the event the terminal is not inserted fully inside the cavity, the movable element may be forced into engagement despite interference with the primary retaining means, as a result for example of breakage or deformation of the contacting parts. As such, incorrect assembly of the terminal may go unnoticed during testing on account, for example, of the terminal being so positioned as to establish at least a precarious electrical contact; which contact, however, is invariably interrupted, with obvious consequences, in applications in which the connector is subject to vibration, as on a motor vehicle. DISCLOSURE OF THE INVENTION It is an object of the present invention to provide an electric connector designed to overcome the aforesaid drawbacks typically associated with known connectors. According to the present invention, there is provided an electric connector comprising an insulating casing with at least one axial cavity; at least one electric terminal housed inside said cavity and at least primary retaining means for retaining said terminal inside said cavity; characterized by comprising movable expulsion means cooperating with said terminal for at least partly expelling said terminal from said cavity in the event said primary retaining means fail to correctly engage said terminal. BRIEF DESCRIPTION OF THE DRAWINGS A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows an in-service longitudinal section of an electric connector in accordance with the teachings of the present invention; Figure 2 shows a longitudinal section, as in Figure 1, of the connector at the preassembly stage; Figures 3, 4 and 5 show longitudinal sections, as in Figure 1, of various operating positions assumed by the connector during assembly, in the event of incomplete terminal insertion. BEST MODE FOR CARRYING OUT THE INVENTION Number 1 in Figures 1 and 2 indicates an electric connector. Connector 1 substantially comprises an insulating casing 2 defining a number of longitudinal through cavities 3 (only one shown) ; and a number of electric terminals 4 housed inside respective cavities 3 and retained therein by primary retaining means 5. Each terminal 4 comprises a substantially box- shaped contact portion 6 located, in use, facing a front opening 7 in the cavity, through which to insert the male terminal 8 (shown partially) of a complementary connector; and a portion 9 for connection to an electric cable 10. Terminal 4 is inserted inside respective cavity 3 through a rear opening 11 in the cavity (Figure 2) from which cable 10 extends in use. Cavities 3 are defined by respective outer lateral walls 12, 13 of casing 2, and are separated by longitudinal partition walls 14. Primary retaining means 5 comprise an elastic lance 15 projecting inside cavity 3 from lateral wall 12 and substantially longitudinally towards front opening 7. On surface 17 of lance 15 facing inwards of cavity 3, there is formed a substantially serrated tooth 18 presenting an inclined side 19 facing rear opening 11, and a side 20 substantially perpendicular to the axis of cavity 3 and facing front opening 7. Between lateral wall 12 and the opposite surface 21 of lance 15, there is formed a gap 22 for enabling lance 15 to flex towards wall 12. Tooth 18 therefore permits insertion of terminal 4 which, as it slides along side 19, flexes lance 15 towards wall 12 (Figure 3) ; and, once terminal 4 is inserted fully inside cavity 3 (Figure 1), lance 15 springs back to its original position by tooth 18 snapping behind rear edge 23 of contact portion 6 of terminal 4 and so defining, with side 20, a stop for preventing withdrawal of terminal 4. Connector 1 also presents a secondary retaining device 24 for retaining terminals 4. Device 24 comprises a movable element 25 integral with and extending transversely over the entire width of casing 2, presenting a substantially L-shaped cross section, and in turn comprising a first wall 26 and a second wall 27 substantially perpendicular to each other. Wall 26 is hinged along its free edge 28 to the front end 29 of wall 12 of casing 2; and the free edge of wall 27 presents a number of catch elements 34 designed to snap inside respective seats 35 formed in casing 2, close to the front edge of wall 13. Element 25 is movable between an open position (Figure 2) corresponding to the molding position of casing 2, and a closed position (Figure 1) wherein wall 27 contacts the front end of casing 2. Wall 27 presents a number of openings 36 which are positioned facing front openings 7 of cavities 3 when element 25 is closed. According to the present invention, device 24 comprises, for each cavity 3, a flexible portion 37 defined by the free end of lance 15 and connected integral with the rest of lance 15 by a small-section blade 38 which acts as a hinge for enabling portion 37 to flex inwards of cavity 3. Portion 37 presents a shaped surface 39 facing the axis of cavity 3 and which cooperates with terminal 4 as described later on. When undeformed, portion 37 is aligned with the rest of lance 15, and surface 21 along the whole of lance 15, including blade 38 and portion 37, is flat. At each cavity 3, element 25 presents an inner appendix 40 presenting a flat end surface 44 cooperating with surface 21 of lance 15 when element 25 is closed. Appendix 40 contacts lance 15 from an intermediate portion of portion 37 to a point beyond blade 38 towards the retaining section of lance 15. Device 24 operates as follows. When terminal 4 is correctly inserted inside cavity 3 (Figure 1), it is retained by tooth 18; lance 15 is restored to its original undeformed position; and, when element 25 is closed and retained in the closed position by catch elements 34 engaging seats 35, appendix 40 fits inside gap 22 and rests against surface 21 of lance 15 for the dual purpose of preventing lance 15 from flexing and so releasing terminal 4, and for reinforcing the weaker portion of lance 15 defined by the smaller section of blade 38. Conversely, when terminal 4 is inserted only partly, as shown in Figure 3, lance 15 remains flexed, due to terminal 4 interfering with tooth 18. Consequently, when element 25 is pushed towards the closed position, appendix 40 interferes with and flexes portion 37 of lance 15 inwards of cavity 3, i.e. substantially rotates it about the virtual hinge defined by blade 38. Upon surface 39 of portion 37 contacting the front edge of terminal 4, and upon element 25 being pushed further to further rotate portion 37, terminal 4 is pushed rearwards along cavity 3 (Figure 5) . The device is so sized as to push terminal 4 rearwards by a distance L - measured from the correct insertion position shown by the dotted line in Figure 5 - sufficient to prevent contact with a complementary terminal inserted inside the cavity; and element 25 is prevented from being closed by portion 37 being arrested, at the the end of the expulsion stroke, against the rest of lance 15 and in turn constituting a stop for element 25. The advantages of connector 1, and particularly device 24, according to the present invention are as follows. In particular, in the event any one of the terminals is not inserted properly inside the cavity and retained by the primary retaining means, it is at least partly expelled from the cavity, so that, even if element 25 is forced into the closed position, the terminal is prevented from establishing any, even precarious, electrical contact, thus enabling the fault to be detected immediately when testing the electric system of which the connector forms part. Clearly, changes may be made to connector 1 as described and illustrated herein without, however, departing from the scope of the present invention. In particular, connector 1 may comprise any number of terminals 4; terminals 4 may be of any type, male or female; and changes may be made to the design and location of portion 37, and to the design and location of the portion of the terminal with which portion 37 interacts.

Claims: CLAIMS 1) An electric connector (1) comprising an insulating casing (2) with at least one axial cavity (3) ; at least one electric terminal (4) housed inside said cavity (3) and at least primary retaining means (5) for retaining said terminal (4) inside said cavity (3) ; characterized by comprising movable expulsion means (37) cooperating with said terminal (4) for at least partly expelling said terminal (4) from said cavity (3) in the event said primary retaining means (5) fail to correctly engage said terminal (4) . 2) A connector as claimed in Claim 1, characterized by comprising secondary retaining means (24) including at least a first movable element (25) designed to snap on to the casing (2) in a closed position for preventing disengagement of said primary retaining means (5) and said terminal (4), said expulsion means (37) comprising at least a second movable element (37) interposed between said first movable element (25) and said terminal (4) , and which said first movable element (25) causes to cooperate with said terminal (4) when said first movable element (25) is moved towards said closed position. 3) A connector as claimed in Claim 2, characterized in that said first movable element (25) is integral with and substantially hinged to said casing (2) . 4) A connector as claimed in Claim 3, characterized in that said second movable element (37) is integral with and substantially hinged to said casing (2) . 5) A connector as claimed in Claim 4, characterized in that said primary retaining means (5) comprise an elastic lance (15) extending inside said cavity (3) and which assumes a deformed position in the event said terminal (4) is not fully inserted; said first movable element (25) comprising at least a thrust portion (40) cooperating with said elastic lance (15) in said deformed position during closure of said first movable element (25) . 6) A connector as claimed in Claim 5, characterized in that said second movable element is defined by an end portion (37) of said elastic lance (15), which is secured to the rest of the elastic lance (15) by a small-section portion (38) . 7) A connector as claimed in Claim 6, characterized in that said end portion (37) is rotated inwards of said cavity (3) by said thrust portion (40) of said first movable element (25) , so as to cooperate with and expel said terminal (4) . 8) A connector as claimed in Claim 6 or 7, characterized in that said thrust portion (40) of said first movable element (25) comprises a surface (44) designed to contact said elastic lance (15) when said first movable element (25) is in the closed position and said elastic lance (15) is in the undeformed position. 9) A method for checking correct insertion of an electric terminal (4) inside a respective cavity (3) in the casing (2) of a connector (1), said connector (1) presenting at least primary retaining means (5) for retaining said terminal (4) inside said cavity (3), characterised by comprising the step of displacing a movable element (25) of said connector (1) for at least partly expelling said terminal (4) from said cavity (3) in the event said primary retaining means (5) fail to correctly engage said terminal (4) . 10) A method for checking correct insertion of an electric terminal (4) inside a respective cavity (3) in the casing (2) of a connector (1), said connector (1) presenting primary retaining means (5) for retaining said terminal (4) inside said cavity (3) and secondary retaining means (24) comprising at least a first movable element (25) designed to snap on to the casing (2) in a closed position, and to cooperate in said position with said primary retaining means (5) for detecting correct engagement and preventing disengagement of said primary retaining means (5) and said terminal (4) ; characterized by comprising the step of at least partly expelling said terminal (4) from said cavity (3) by moving said first movable element (25) towards said closed position, in the event said primary retaining means (5) fail to correctly engage said terminal (4) .

Inventors: BIGOTTO PIER CARLO, GENTA ALESSANDRO, BIGOTTO, PIER, CARLO, GENTA, ALESSANDRO
Applicants: BIGOTTO PIER CARLO, FRAMATOME CONNECTORS INT, GENTA ALESSANDRO, BIGOTTO, PIER, CARLO, FRAMATOME CONNECTORS INTERNATIONAL, S.A., GENTA, ALESSANDRO
Application year: 1995
Main classification: H01R13
IPC codes: H01R13, H01R43