Abstract:
An electrical connector element ( 1 ) includes a connector body ( 2 ) wherein contact housings ( 20 ) are formed, electrical contacts ( 4 ) crimped to respective electrical cables ( 8 ) and able to be housed in the contact housings ( 20 ) of the connector body ( 2 ) and locking elements ( 5 ) designed to be fixed in the connector body ( 2 ) after insertion of the contacts ( 4 ). The locking elements ( 5 ) include stops ( 55 ), which protrude into the contact housings ( 20 ) so as to prevent the contacts ( 4 ) from coming out of their housings.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention refers to an electrical connector element for conductors with crimped contacts. 
   2. Description of the Related Art 
   As is known, electrical connectors are generally composed of a pair of connector elements. Each connector element comprises an insulated body (commonly known as connector body) wherein are mounted the respective contacts (male and female) which are connected to electrical cables with one of the various connection technologies available, such as screw, spring, insulation piercing and crimping. 
   In crimping connection technology, the top portion of the contact is crimped, by means of an appropriate crimping tool, to the end of the wires of the electrical cable, so as to form an optimal electrical contact. Crimping is the preferred connection technology in professional and military applications, where the connection must stand up to strong mechanical stresses (impacts and vibrations) and to aggressive atmospheres. Once the contact has been crimped with the electrical cable, it is inserted into its housing in the connector body. 
   Therefore, for connectors with crimped contacts, a factor of particular importance is retention of the contacts in the connector body during coupling with the other electrical connector element and in the event of stresses (tractions and/or rotations) on the cables, which are transmitted to the contacts. 
   In the connector elements of the prior art, locking of crimped contacts takes place by means of a spring (generally of steel or of plastic) disposed inside the connector body. Said spring is elastically deformed during insertion of the contact and then it returns to its original shape, retaining the contact in its housing. Said contact locking system presents some drawbacks: 
   Variation in the elasticity of the spring is related to the tolerances of the materials and of the manufacturing processes. 
   In order to be able to remove the contacts from the connector body a particular extractor tool is necessary which, once inserted in the housing of the contact, compresses the spring by a sufficient amount to allow extraction of the contact. 
   To be able to retain the contacts firmly in their housings, springs whose strength and stiffness increases as the dimensions of the spring increase are necessary. Thus, in the case of large-sized contacts, it is necessary to oversize the spring and to apply greater stresses thereto for release (extraction) of the contacts. As a result insulating connector bodies with a greater mechanical strength must be made, to avoid breakage thereof during operation of the extractor tool. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to eliminate the drawbacks of the prior art, providing an electrical connector element for conductors with crimped contacts, which ensures an efficient, effective and safe locking system for the contacts. 
   Another object of the present invention is to provide such an electrical connector element for conductors with crimped contacts that is cheap, easy to make and easy to assemble. 
   These objects are achieved in accordance with the invention to provide an electrical connector element ( 1 ) that includes a connector body ( 2 ) wherein contact housings ( 20 ) are formed, electrical contacts ( 4 ) crimped to respective electrical cables ( 8 ) and adapted to be accommodated in said contact housings ( 20 ) of the connector body ( 2 ), and locking means ( 5 ) adapted to be fixed to said connector body ( 2 ) after insertion of the contacts ( 4 ), said locking means ( 5 ) comprising stops ( 55 ) which protrude into said contact housings ( 20 ) so as to prevent said contacts ( 4 ) from coming out of their seats. 
   Advantageous embodiments of the invention are apparent from the dependent claims. The electrical connector element according to the invention comprises a connector body wherein are formed contact housings adapted to house electrical contacts crimped to respective electrical cables. The main characteristic of the invention is represented by the fact that said connector element comprises locking means adapted to be fixed in said connector body, after insertion of the contacts. The locking means comprise stops, which protrude into the contact housings so as to prevent the contacts from coming out of their seats. 
   Said locking means allow the use of the contact-locking springs, and thus all the drawbacks related to said springs, to be eliminated. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     Further characteristics of the invention are made clearer by the detailed description that follows, referring to a purely exemplifying and therefore non-limiting embodiment thereof, illustrated in the appended drawings, in which: 
       FIG. 1  is a perspective view of a connector element according to the invention, illustrating in an exploded view a locking element, two female contacts destined to be crimped to an electrical cable, a connector body and two locking keys; 
       FIG. 2  is a perspective view, illustrating the female contacts of  FIG. 1  crimped on the electrical cables; 
       FIGS. 3 and 4  are two sectional views of the connector body taken along planes passing through the respective diagonals of the connector body; 
       FIG. 5  is a sectional view of the locking element taken along the plane of section V-V of  FIG. 1 ; 
       FIG. 6  is a perspective view illustrating the electrical connector element of  FIG. 1  assembled, but with the locking key again in an exploded view; 
       FIG. 7  is a perspective view illustrating the electrical connector element of  FIG. 6 , in which the locking keys have been assembled; 
       FIG. 8  is a top plan view of the assembled connector element of  FIG. 7 ; 
       FIG. 9  is a sectional view of the assembled connector element, taken along the line IX-IX′ of  FIG. 8 ; 
       FIG. 10  is a perspective view, showing the connector element of  FIG. 7  assembled and mounted in a connector frame. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The connector element according to the invention, denoted as a whole with reference numeral  1 , is described with the aid of the Figures. As shown in  FIG. 1 , the connector element  1  comprises: 
   an insulating connector body  2 , 
   two electrical contacts  4  destined to be housed in the connector body  2 , 
   a locking element  5  adapted to lock the electrical contacts  4  inside the connector body  2  and 
   two locking keys  7  adapted to lock the locking element  5  inside the connector body  2 . 
   Each electrical contact  4  is made of a conductive metal material, is substantially cylindrical in shape and has at one end a top collar  40  which defines a housing  41  adapted to accommodate the wires of an electrical conductor cable  8  ( FIG. 2 ). 
   Beneath the collar  40  of the contact  4  there is defined a cylindrical crimping portion  42 , which is crimped with a suitable crimping tool, so as to lock the wires of the conducting cable  8  inside the seat  41  of the contact. 
   Beneath the crimping portion  42  there extends an intermediate collar  43  with a larger diameter beneath which a cylindrical portion  44  with a smaller diameter extends, which defines the contact proper. In this manner an annular abutment surface  45  is defined between the intermediate collar  43  and the proper contact portion  44 . 
   In the Figures a female contact  4  has been illustrated by way of example. Thus, the cylindrical portion  44  is hollow on the inside and open at its end to be able to receive therein a male contact. For this purpose longitudinal slots  46  are formed in the cylindrical portion  44  which allow elastic yielding of the cylindrical portion  44 , when it receives the male contact therein. 
   For greater clarity, a connector element  1  with contacts  4  without an electrical cable  8  will be illustrated in the Figures; however, it is obvious that the contacts  4  must be crimped to the cable  8  before being assembled in the connector element  1 . Furthermore, even if a connector element with female contacts  4  has been illustrated in the Figures, it is obvious that the invention also extends to connector elements with male contacts. 
   The connector body  2  comprises a body  22  taking the form of a parallelepiped block substantially square in cross section. The bottom part of the connector body is smaller in size and is the coupling portion, which is of such a shape as to be able to couple, in a per se known manner, with a complementary coupling portion of another connector element. 
   As shown better in  FIG. 3 , two substantially cylindrical housings  20  are formed in the connector body  2 , destined to accommodate the contacts  4 . 
   In the Figures, by way of example the axes of the housings  20  lie on a plane passing through a diagonal of the body  22  of the connector body and the housings  20  are separated from each other by a partition  21  lying on the plane passing through the other diagonal of the body  22 . However, the housings  20  can differ in number and can be disposed differently. 
   Each seat  20  is made like a through channel consisting of a first hole  23  with a larger diameter, a second hole  24  with a smaller diameter than the first one and a third hole  25  with a smaller diameter than the second one. In this manner a first annular abutment surface  26  is defined between the first hole  23  and the second hole  24  and a second annular abutment surface  27  is defined between the second hole  24  and the third hole  25 . 
   A widening  32 , which extends for about 180° in order to give rise to a semicircular abutment surface, is formed in the top part of the first-hole  23 . 
   The contacts  4  are disposed in the respective housings  20  of the connector body, so that the annular abutment surface  45  of the intermediate collar  43  of each contact  4  abuts against the first abutment surface  26  of the respective seat  20 , preventing axial movement downward (with reference to the Figures) of the contact  4 . In this situation, the bottom end of the cylindrical portion  44  of the contact proper is tightly close to the second abutment surface  27  of the housing  20 . 
   As shown also in  FIG. 4 , inside the body  22  are formed two further seats  28  disposed near the two corners of the body on one side and on the other with respect to the contact housings  20 . The seats  28  are substantially triangular shaped in cross section, are upwardly open and end in a bottom abutment wall  29 . 
   Two rectangular slots  30  (only one visible in  FIGS. 1 and 4 ) which communicate with the respective seats  28  are formed in the side wall of the body  22 . Beneath each slot  30  a tapered entry guide  31  formed in the outer side surface of the body  22  is defined. 
   Each slot  30  of the body of the connector body is designed to be engaged by a substantially L-shaped locking key  7  ( FIG. 1 ). The locking key  7  comprises a tapered surface  70  destined to cooperate with the tapered surface  31  of the wall of the body  22  of the connector body. Furthermore the key  7  has a protruding tooth  71 , which engages in the slot  30  of the wall of the body of the connector body. Outwardly protruding ribs  72  are provided on the side walls of the key  7  to allow an engagement with a certain interference in the slot  30 . 
   In order to keep the contacts  4  locked in the housings  20  of the connector body, a locking element  5  in the form of a bridge consisting of two supporting legs  50  connected to a top joining element  51  is used. The locking element  5  can be made in a single piece by injection moulding of plastic materials. 
   Each leg  50  is substantially triangular in cross section and of such a size as to be able to be inserted in the respective seats  28  formed in the body of the connector body  2 . For this purpose, the corners of the seats  28  are chamfered and each leg  50  also has a chamfered edge  52 . In this manner, when the legs  50  of the locking element are inserted in their seats  28  in the connector body, the edges  52  of the legs slide in a guided manner on the corners of the seats  28  of the connector body. 
   As shown also in  FIG. 5 , each leg has two longitudinal seats  53  (only one visible in  FIG. 1 ) ending in a bottom abutment surface  54 . 
   The top joining element  51  of the locking element  5  is substantially X-shaped in plan view and has two semi-cylindrical stops  55  (only one visible in  FIG. 1 ). As shown in  FIG. 5 , the two semi-cylindrical stops  55  are disposed like two Cs with the concave parts facing outwards and the convex parts spaced apart from each other by a space  56  sufficient to allow the passage of the intermediate partition  21 , which separates the two contact housings. 
   Each semi-cylindrical stop  55  of the locking device is of such a size as to be able to be housed in the widening  32  of each contact housing  20 . Then, after the contacts  4  have been inserted in their housings  20  in the connector body, the locking element  5  also is inserted in the connector body  2 , as shown in  FIG. 6 . That is, the legs  50  of the locking element  5  are inserted into the corner seats  28  of the connector body, until the base of the legs  50  abuts against the abutment surface  29  ( FIG. 4 ) of the seats  28  of the connector body. 
   In this situation the semi-cylindrical stops  55  of the locking element are housed in the widenings  32  of the contact housings  20 , the bottom ends of the semi-cylindrical stops  55  of the locking element abut against the top end of the collar  40  of the contacts and the partition  21  between the two housings  20  of the contacts is disposed between the two stops  55 . 
   At this point, in order to lock the locking element  5  inside the connector body  2 , as shown in  FIG. 7 , the keys  7  are inserted in the respective slots  30  of the side wall of the connector body. In this operation the tapered surface  70  of the key  7  abuts against the tapered surface  31  of the wall of the body  22  of the connector body beneath the slot  30  and the ribs  72  of the key  7  ensure insertion with a certain forcing of the protruding part  71  of the key in the slot  30  of the connector body. 
   Furthermore it should be noted that the particular shape of the key  7  and in particular the tapered surface  70  thereof which cooperates with the tapered surface  31  of the wall of the body  22  of the connector body allow easy removal of the key, possibly with the aid of the tip of a screwdriver which levers beneath the end of the key. 
   As shown in  FIG. 9 , the retaining tooth  71  of each key  7  enters the longitudinal seat  53  of the respective leg  50  of the locking element and abuts on the abutment surface  54  of the base of the respective leg  50 , thus preventing axial extraction of the locking element  5 . 
   As a result, each contact  4  is locked in its seat  20  and any axial movement thereof is prevented. In fact, the top end of the top collar  40  of the contact will abut against the bottom end of the semi-cylindrical stops  55  of the locking element  5  and the abutment surface  45  of the intermediate collar  43  of each contact  4  will abut against the abutment surface  26  of the intermediate hole  24  of the contact housing  20 . 
   Returning to  FIG. 1 , four protrusions  35  (two protrusions  35  in each wall) are formed in two opposite side walls of the body  22  of the connector body. The two protrusions  35  of one wall are spaced apart from each other and aligned. One protrusion  35  is situated above the respective slot  30  of the key  7 . Furthermore grooves  36  are formed in the edges of the body  22  of the connector body. In each wall of the connector body wherein there are protrusions  35 , a slot  37  is provided disposed beneath the protrusions  35  in a median position. 
   Such a configuration of the side walls of the connector body  2  serves to apply on the connector body  2  a frame  9 , like that illustrated in  FIG. 10 . The frame  9  is formed by four rectangular metal plates, which surround the middle part of the connector body  2 . The frame  9  serves as a seat for the earth contacts  91  and also contains, besides the connector body  2 , other connector bodies (in the case illustrated, the connector bodies  92  and  93 ). 
   In this manner the top edge of the frame  9  abuts against the protrusions  35  of the connector body  2  and the bottom edge of the frame  9  is locked by means of two keys  90  (only one visible in  FIG. 10 ). Each key  90  has three teeth, which engage in a snap coupling relationship in the two slots  26  in the edges of the body of the connector body and in the intermediate slot  37  in the wall of the body of the connector body. 
   It should be noted that the walls of the frame  9  compress the keys  7  which lock the locking element  5 , thus preventing any possibility of disengagement of said keys  7 , even in the case of particularly violent vibrations or impacts. 
   It must moreover be considered that the stops  55  of the locking element  5  have been configured in a semi-cylindrical shape to be able to rest on a large surface of the upper edge of the contact  4 . This solution ensures greater safety with respect to springs of the prior art, which have a small surface that locks the contact. Therefore the connector element  1  ensures that the contact  4  is retained even in the presence of strong traction on the electrical cable. 
   Even if a connector element with two poles disposed diagonally has been illustrated in the Figures, it is obvious that the present invention also extends to multipolar connector elements in which a plurality of poles disposed side by side in two rows is provided. 
   Numerous changes and modifications of detail within the reach of a person skilled in the art can be made to the present embodiment of the invention without thereby departing from the scope of the invention as set forth in the appended claims.