Abstract:
An electrical connector system comprising an engaging device ( 34, 18 ) for engaging the fitting section ( 32 ) with the receiving section ( 16 ); and a releasing device ( 24, 19 ) for releasing the engaging means. The engaging device comprises a circumferential groove ( 33 ) provided in the fitting section ( 32 ); a resiliently expandable member ( 34 ) provided in the circumferential groove; a pressure portion ( 19 ) provided on a front inside of the receiving section ( 16 ) for abutment with the resiliently expandable member ( 34 ) upon plugging operation; and an engaging groove ( 18 ) provided in an inside of the receiving section for engagement with the resiliently expandable member ( 34 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical connectors and, more particularly, to a push-pull type electrical connector. 
     2. Description of the Related Art 
     FIG. 8 shows part of a conventional push-pull type electrical connector. A connector  50  comprises a housing body  51  having a front tubular section  52 . A sleeve  54  is biased forwardly by a coil spring  53  along the tubular section  52 . Circumferential projections  55  and  56  are provided at the front end and an end portion of the tubular section  52 . A circumferential projection  57  is provided on the inside middle portion of the sleeve  54  to determine the most forward position of the sleeve  54  which is biased by the coil spring  53  and define an annular space  59  between the sleeve  54  and the tubular section  52 . A circumferential recess  58  is provided on the inside front end of the sleeve  54  at a position corresponding to the circumferential projection  55  of the tubular section  52 . 
     Another connector  60  comprises a housing body  61  having an outer tubular section  62  to form an annular receiving space  63  for receiving the tubular section  52  of the connector  50  while the outer tubular section  62  enters the annular space  59 . The outer tubular section  62  has a pair of axial slits and a circumferential slit  64  to form a cantilevered flexible arm  65  which has an inward projection  66  at the front free end. 
     When the connector  60  is plugged into the connector  50  in the direction of an arrow in FIG. 8, the outer tubular section  62  enters the annular space  59  of the connector  50 . The inward projection  66  of the flexible arm  65  is pushed outwardly by the circumferential projection  55  to flex the flexible arm  65 , which pushes rearwardly the sleeve  54  at the shoulder of the circumferential recess  58  against the bias of the coil spring  53 . When the inward projection  66  passes over and engages with the circumferential projection  55 , the flexible arm  65  returns to the normal position. Then, the sleeve  54  returns to the front position so that even if the flexible arm  65  receives an external force in the radial direction, it cannot be flexed outwardly owing to the sleeve  54 , thus locking the plugging of the connectors. 
     To separate the connectors, the sleeve  54  is pulled rearwardly against the coil spring  53  while the other connector  60  is pulled out of the connector  50 . 
     However, the conventional connectors are too long in the plugging direction and difficult to handle. The flexible arm  65  of the other connector  60  must be sufficiently flexible to provide a predetermined amount of flexure. In order to assure engagement between the connectors  50  and  60 , the engaging projections  55  and  66  must be large. In order that the inward projection  66  passes the circumferential projection  55 , the flexible arm  65  must be long, leading to the long connectors  60  and  50 . 
     Upon plugging, the sleeve  54  of the connector  50  must retreat to a large extent, which means that the operator cannot work by holding both the connectors  50  and  60  because if the operator holds the sleeve  54 , the sleeve cannot retreat. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide an electrical connector which is compact and easy to handle. 
     The invention relates to an electrical connector system comprising a first connector comprising a first housing having a front tubular receiving section; a second connector comprising a second housing having a front tubular fitting section for fitting into the receiving section; an engaging device for engaging the fitting section with the receiving section; and a releasing device for releasing the engaging device. 
     According to the invention, the engaging device comprises a circumferential groove provided in the fitting section of the second connector; a resiliently expandable member provided on the circumferential groove; a pressure portion provided on a front inside of the receiving section of the first connector for abutment with the resiliently expandable member upon plugging operation; and an engaging groove provided in an inside of the receiving section of the first connector for engagement with the resiliently expandable member. 
     The release device comprises a spring provided in either the first housing or the second housing; a sleeve biased by the spring for sliding along either the receiving section or the fitting section; a release projection provided on an inside front end of the sleeve; and a tapered face provided on at least one of the release projection and the resiliently expandable member for permitting the release projection to ride on the resiliently expandable member when the sleeve is moved rearwardly. 
     Upon plugging, the pressure portion of the first connector compresses the resiliently expandable member of the second connector so that the second connector can pass the pressure portion of the first connector. When the resiliently expandable member reaches the engaging groove, it returns to the original form so that the connectors are connected via the resiliently expandable member. 
     To release the connection of the connectors, the sleeve is moved rearwardly so that the release projection rides on and compresses the resiliently expandable member. Consequently, the resiliently expandable member is released from the engaging groove so that the connectors can be separated. 
     According to the invention, it is preferred that the second connector further comprises a regulation piece extending to the circumferential groove for preventing excessive expansion of the resiliently expandable member, thereby assuring stable operation of the resiliently expandable member. 
     According to an embodiment of the invention, the resiliently expandable member is a C-shaped ring having a slit at a position in the circular direction. 
     According to another embodiment of the invention, the second connector further comprises a projecting piece for engagement with a notch of the C-shaped ring to prevent the C-shaped ring from shifting in the circumferential direction. For example, the regulation piece is placed at the slit to control deformation of the C-shaped ring. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational, partially sectional, view of a pair of electrical connectors according to an embodiment of the invention; 
     FIG. 2 is a sectional view of the electrical connectors prior to plugging; 
     FIG. 3 is a sectional view of the electrical connectors which have been plugged; 
     FIG.  4 (A) is a sectional view of the electrical connectors taken at a position other than that of FIG. 1; 
     FIG.  4 (B) is a sectional view taken along line B—B of FIG.  4 (A); 
     FIG.  4 (C) is a sectional view taken along line C—C of FIG.  4 (A); 
     FIG. 5 is a perspective view of one of the electrical connectors taken along line C—C of FIG.  4 (A); 
     FIGS.  6 (A), (B), and (C) are sectional views of the electrical connectors taken at a position other than those of FIGS.  1  and  4 (A) at a time of plugging, during separation, and after separation, respectively; 
     FIG. 7 is a sectional view of a pair of electrical connector according to another embodiment of the invention; and 
     FIG. 8 is a sectional view of conventional electrical connectors. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the invention will now be described with reference to the accompanying drawings, wherein FIGS. 1-3 show, in section, a pair of electrical connectors which are being plugged, prior to plugging, and have been plugged, respectively. 
     A connector  10  is adapted to plug over another connector  30  for connection. The connector  10  comprises a tubular housing  11  made from an dielectric material around an axis  12  and a plurality of contact elements  13  extending in the tubular housing  11  in parallel to the axis  12 . Each contact element  13  has at the front end a female contact section  13 A adjacent to an opening  14  of the tubular housing  11  and at the rear end a connection section  13 B extending through the tubular housing  11 . 
     The tubular housing  11  has a receiving section  16  having a receiving space  15  with an opening at the front end. An O-ring  17  is provided at the rear end of the receiving space  15  for sealing. An engaging groove  18  is provided in the receiving section  16 . A pressure portion  19  is provided on the inside front edge of the receiving section  16  in front of the engaging groove  18 . The front edge  19 A of the pressure portion  19  is tapered. The receiving section  16 , the receiving space  15 , the engaging groove  18 , and the pressure portion  19  will be described in more detail relative to the other connector  30 . 
     A small-diameter section  20  extends rearwardly from the receiving section  16  and has a threaded section at the rear portion to which a holding tube  21  is fixed. A coil spring  23  is provided in an annular space  22 . A sleeve  24  is provided around the tubular housing  11 . A corrugated surface  24 A is provided on the sleeve  24  for facilitating a back-and-forth operation. A circumferential engaging projection  24 B is provided at an inside middle portion of the sleeve  24 . The sleeve  24  is biased forwardly by the coil spring  23  so that the engaging projection  24 B abuts against the rear wall  16 A of the receiving section  16 . Also, it is guided by the tubular section  16  at the front portion and by the holding tubular body  21  at the rear portion. 
     The other connector  30  comprises an insulating housing  31  having a fitting or front tubular section  32  which has sufficient inside and outside diameters and length to be received by the receiving space  15  of the connector  10 . An annular projection  32 B extends forwardly from the tubular section  32  and has an inside diameter such that when the tubular section  32  enters the receiving space  15 , it compresses the O-ring  17  in the receiving space  15  in the radial direction. The tubular section  32  has a fitting surface  32 A which is fitted in the receiving section  16  of the connector  10 . 
     A circumferential groove  33  is provided in the housing  31  for receiving a C-shaped ring  34  which is able to resiliently shrink and expand. Upon expanding, the C-shaped ring projects in the radial direction from the circumferential groove  33 . The front outer corner  34 A of the C-shaped ring  34  is tapered so that it abuts on the tapered front edge  19 A of the pressure portion  19 . That is, when the tubular section  32  enters the receiving space of the connector  10 , the C-shaped ring  34  is compressed by the tapered face  19 A permitting further advance of the tubular section  32 . Upon passing the pressure portion  19 , the C-shaped ring  34  returns to the original form or expands into and engages with the engaging groove  18  and, thus, is prevented from backward movement. 
     In this embodiment, the cavity  35  of the tubular section  32  receives the front section of the connector  10  upon plugging. However, the front ends of housings of both the connectors  10  and  30  may be made to abut against each other. 
     FIG.  4 (A) is a cross-sectional view of the connectors rotated by 90 degrees relative to the connector of FIG.  1 . FIGS.  4 (B) and (C) are sectional views taken along lines B—B and C—C of FIG.  4 (A), respectively. FIG. 5 is a perspective view of the other connector taken along line B—B of FIG.  4 (A). FIGS. 1-3 are sectional views taken along lines X—X of FIGS.  4 (B) and (C) and FIG.  4 (A) is a sectional view taken long line Y—Y of FIGS.  4 (B) and (C). The same or like parts are given like reference numerals throughout the specification. 
     A regulation piece  41  extends forwardly from the tubular section  32  to the circumferential groove  33 . A projecting piece  42  extends forwardly from the tubular section  32  at a position different from the regulation piece  41 . It engages with a notch  43  formed on the rear end of the C-shaped ring  34  to prevent the circumferential shift of the C-shaped ring  34 . The regulation piece  41  has a width sufficiently large to cover the slit  34 A of the C-shaped ring  34  to prevent excessive expansion of the C-shaped ring  34 . The number of the regulation and projecting pieces may vary. 
     A pair of supporting portions  44  are provided on the tubular section  32  to keep the C-shaped ring  34  not only concentric with the circumferential groove  33  but also from moving in the radial direction. The plugging sections of the connectors  10  and  30  have a substantially cross-shaped section and a key portion to prevent any plugging offset in the circumferential direction thereby assuring that the contact elements are arranged in a predetermined relationship. 
     As shown in FIG.  4 (B), release projections  45  are provided on the front end inner surface of the sleeve  24  at middle points between lines X—X and Y—Y. As shown in FIG.  6 (A), each release projection  45  has a oblique abutting face or tapered face  45 A at the rear edge such that the tapered face  45 A abuts against the C-shaped ring  34  when the sleeve  24  is moved rearwardly. 
     The operation of the connectors will be described below. 
     (1) The plugging is made in the order of FIGS.  2 - 1 - 3 . When the connector under the condition of FIG. 2 is brought to the condition of FIG. 1 (while the sleeve is not moved), the tapered face  34 A of the C-shaped ring  34  abuts against the tapered face  19 A of the pressure portion  19  so that the C-shaped ring  34  is compressed and passes the pressure portion  19 . 
     (2) When the C-shaped ring  34  reaches the engaging groove  18  (by this time, the contact elements have been connected), it returns to the original form. Consequently, the C-shaped ring  34  engages with the engaging groove  18  to lock connection of both the connectors  10  and  30 . When both the connectors  10  and  30  are connected, the annular projection  32 B of the connector  30  presses the O-ring  17  for making seal. 
     (3) To separate the connectors  10  and  30 , as shown in FIG.  6 (A), the sleeve  24  of the connector  10  is moved rearwardly against the coil spring  23  so that the tapered face  45 A of the sleeve  24  is on the C-shaped ring  34  and compresses it. See FIG.  6 (B). Thus, as shown in FIG.  6 (C), it is possible to separate the connectors  10  and  30 , when the sleeve  24  is returned to the original position by the coil spring  23 . 
     The sleeve may be provided on either of the connectors. In FIG. 7, the sleeve is provided on the connector  30 . The C-shaped ring may be any resiliently expandable member. For example, cantilevered members extend from the connector in the circumferential direction so that the free ends are able to expand in the circumferential direction. 
     As has been described above, according to the invention, both the connectors are engaged with each other via the resiliently expandable member so that the connectors is made shorter and finer and more compact. The plugging operation of the connectors has no influence on the sleeve for release so that the sleeve can be held to make the plugging operation, making the work easy.