Abstract:
An electrical connector includes first and second connector members each having respective complementary connecting elements, with the second connector member having an annular insert adapted for tight-fitting insertion in an annular recess of the first connector member. Attached to the second member is a circular spring having inwardly directed resilient tines which engage an outer surface of the second member for coupling the two connector members together in a locked manner. Attached to and disposed about the first member is a fixed apertured outer sleeve and the movable combination of an apertured inner sleeve and a release sleeve. Insertion of the flat blade of a tool into an aligned pair of outer and inner apertures, followed by rotation of the tool, causes its blade to displace the release sleeve into engagement with the spring, bending its tines and releasing the two connector members from one another.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to electrical connectors and is particularly directed to an electrical connector having a locking feature for increased safety and security. 
       BACKGROUND OF THE INVENTION 
       [0002]    In some applications, such as environments including hazardous, combustible or explosive gases, referred to as “Zone II” applications, it is desirable to have a secure coupling between male and female electrical connectors so that the connectors cannot be inadvertently disconnected which can cause a possible arc or inadvertently interrupt the operation of a machine on a production line. Thus, it is desirable to have a locking feature in such connectors. However, in the case of an urgent matter or simply for convenience, it is also desirable that the two connectors may be disconnected by a tool which is normally in the immediate area. A common blade screw driver is such an acceptable, convenient tool, but its application to a connector in an unlocking procedure, must be convenient and safe. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0003]    The present invention relates to an electrical connector assembly comprising a male and a female connector. For convenience, one connector, which may be either the male or female, is referred to as the “first” connector, and the other connector is referred to as the “second” connector. The first connector includes a retainer spring for releasably securing the two connectors together. 
         [0004]    The electrical connectors with which the illustrated embodiment is concerned are plug type connectors. In particular, the connecting element may be pins (on one connector) and sleeves on the other. Typically, a plug type connector is connected at the end of a cable including an outer insulating sheath. As used herein, “forward” refers to the direction of insertion of a connector (whether it is the male connector or the female connector). Thus, both connectors are moved in the “forward” direction in order to accomplish connection. Second, the term “axial” refers to the axis of a cable which passes through the center of the connector and the term “radial” refers to a direction in a plane perpendicular to the “axis” as defined. Thus, male and female plug connectors are assembled or “connected” by passing the two connectors, each in a “forward” direction along an “axial” line passing through the center of both connectors. These terms are for convenience and clarity of description and not intended to be limitations of the invention. In the illustrated embodiment, the female connector has socket elements for receiving associated connector pins on the male connector. 
         [0005]    The first connector (male or female) includes a generally annular retainer spring having a circular base or ring and inwardly (i.e., centrally) projecting flexible tines which are inclined slightly in the direction of insertion of the second connector. The inner edges of the tines define an opening for receiving and coupling to the outer surface of a cylindrical insert of the second connector. As the second connector is assembled to the first connector, the cylindrical insert of the second connector engages the tines of the retainer spring and deflects the tines of the retainer spring in the direction of insertion of the second connector, thereby enlarging the receiving opening formed by the distal ends of the tines, and admitting the second connector to the coupling position. Upon insertion, the distal ends of the tines lock against the outer surface of the second connector (in the illustrated embodiment, by means of a peripheral rim) thereby preventing separation of the two connectors. 
         [0006]    The first connector has an axially slidable member referred to as an inner sleeve, which is provided with a forward flange (“forward” in the direction of connection of the first connector), in the form of an annular wall. The forward flange or annular wall of the inner sleeve, in the connected position of the connector, engages a forward portion of a spring actuator or release sleeve which unlocks the two connectors through the use of a common tool such as a blade screw driver. 
         [0007]    The outer sleeve of the first connector is received on the inner sleeve, and the outer sleeve includes a rear wall which fixes the outer sleeve against movement in an axial (connecting) direction, but permits free rotation of the outer sleeve about the axis of the connector. 
         [0008]    The inner sleeve is also freely rotatable. The outer sleeve has a first plurality of openings, each extending in a circumferential direction over a limited distance, and the inner sleeve has a second plurality (preferably different in number from the first plurality of openings of the outer sleeve) which also extend circumferentially over a limited distance. The openings on the outer sleeve and the openings on the inner sleeve are constructed and arranged so that at least one pair of openings (that is, one on the outer sleeve and one on the inner sleeve) align to form a space sufficient to receive the blade of a common tool, such as a screw driver. Each of the first plurality of openings disposed on the circumferential, cylindrical side wall of the outer sleeve includes a respective first reaction surface at the forward end of each opening. Similarly, each of the second plurality of openings disposed on the circumferential, cylindrical side wall of the inner sleeve includes a respective second reaction surface at the rear end of each opening. The first reaction surfaces on the outer sleeve are axially spaced from the second reaction surfaces on the inner sleeve. 
         [0009]    When the second connector is assembled to the first connector, the plug of the second connector engages the tines of the retainer spring of the first connector and displaces inner portions of the tines in the direction of insertion, thereby bending the tines so that the inner edges of the tines form an enlarged opening for receiving the plug of the second connector. The plug of the second connector may include a circumferential rim which passes beneath the opening tines of the first connector; and the tines engage the rear end of the circumferential rim to lock the two connectors together. 
         [0010]    The spacing between the second reaction surfaces on the inner sleeve (which extend generally in a radial plane) and the first reaction surfaces on the outer sleeve (which also extend generally in a radial plane) is such as to receive the blade of a common, generally available tool such as a screw driver. The distance between the two reaction surfaces (one on the rear portion of an opening on the inner sleeve and the other on the forward portion of an opening on the outer sleeve) when the openings are aligned defines a space which is approximately equal to the width (i.e., shorter dimension) of the blade of the tool. 
         [0011]    Thus, when the blade of the uncoupling tool is inserted through corresponding aligned openings, one in the outer sleeve and one in the inner sleeve, one lateral edge of the lower end portion, or tip, of the tool blade engages a reaction surface of an opening on the inner sleeve and the opposite lateral edge of the blade engages a reaction surface on the outer sleeve. When the tool is then twisted about its longitudinal axis (i.e., along a radius of the two connectors), the inner sleeve is moved rearwardly relative to the first connector (i.e., in the direction of connection for the second connector). This forces the inner sleeve of the first connector rearwardly, and the forward flange of the inner sleeve engages a forward surface of the actuator sleeve, causing the actuator sleeve to engage inner end portions of the tines of the retainer spring and urge them rearwardly to enlarge the opening formed by the inner end portions of the tines of the retainer spring, thus freeing the plug of the second connector so that it may be removed from the first connector. 
         [0012]    In the illustrated and preferred embodiment, there are three equally spaced openings disposed about the circumference of the outer sleeve and four equally spaced openings disposed about the circumference of the inner sleeve. Preferably, the size, number and spacing of the openings on the inner and outer sleeves is such that there is always one slot on the outer sleeve which is aligned with one slot on the inner sleeve to provide a space to receive a disconnecting tool having a blade-type edge. 
         [0013]    The openings on the outer sleeve (sometimes referred to as the “outer openings”) are arranged axially such that a forward (i.e., in the direction of connection) edge of the outer openings is spaced forwardly of a rear edge of the aligned openings on the inner sleeve to provide an axial space sufficient to receive the leading edge of the blade of the disconnecting tool. 
         [0014]    For clarity, the blade of a flat screw driver (i.e., as opposed to a Phillips screw driver) has two relatively short, flat sides and two relatively long, flat sides. The two long sides provide bearing surfaces for engaging the slot of a screw and applying torque. When the tool is inserted into the aligned openings of the inner and outer sleeves of the connectors of the present invention, one bearing surface of the tool (the one facing the direction of insertion of the first connector) lies adjacent the reaction surface on the forward edge of the slot in the outer sleeve, and the opposing bearing surface of the tool lies adjacent a reaction surface on the rear edge of the radially aligned slot on the inner sleeve. 
         [0015]    By turning the tool (in the manner for inserting or removing a fastener), the inner sleeve of the first connector is moved rearwardly. The inner sleeve includes a member (a circular peripheral flange in the illustrated embodiment) which engages and translates the actuator sleeve axially rearwardly (i.e., in the direction of disconnection). The actuator sleeve of the connector includes an inner frusto-conical bearing surface which engages the tines of the spring to force the tines to an unlock, or release, position, freeing the latched second connector and permitting its removal. 
         [0016]    The connectors may be assembled together without the tool. During connection, a leading portion of the insert of the second connector forces the tines of the locking spring forward in the direction of insertion of the second connector such that the tines “open” to form an enlarged receiving opening. When an outer peripheral rim on the insert of the second connector passes beneath the inner edges of the tines on the locking spring, the tines spring back to form a reduced opening, thereby engaging the rear surface of the peripheral ridge on the insert extension of the second connector, and locking the two connectors together in the assembled, operative position. 
         [0017]    As indicated above, to disconnect the connector, the tool is inserted into aligned openings, one on the outer sleeve, and the other on the inner sleeve. The tool is then twisted to translate the spring release actuator which forces the tines to the open or unlock position so that the second connector may be removed manually. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a fragmentary perspective view of two mating electrical connectors incorporating the present invention in assembled relation; 
           [0019]      FIG. 2  is a fragmentary longitudinal cross-sectional view of the two connectors of  FIG. 1  and taken along a plane extending along the axes of the two connectors in the connected or assembled position with an uncoupling tool (shown in fragmentary form) inserted between the reaction surfaces of the openings in the inner and outer sleeves, prior to uncoupling; 
           [0020]      FIG. 3  is a view similar to  FIG. 2  with the uncoupling tool turned so that the inner sleeve is in the release position to allow for disconnecting the two electrical connectors; 
           [0021]      FIG. 4  is a transverse cross-sectional view of the two connectors taken in a plane perpendicular to the axes of the connectors and extending through the openings in the inner and outer sleeves, with the blade of the uncoupling tool shown positioned within aligned openings in the inner and outer sleeves; 
           [0022]      FIG. 5  is a perspective view of the outer sleeve of the first connector; and 
           [0023]      FIG. 6  is a perspective view of the inner sleeve of the first connector. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Referring first to  FIG. 1 , the present invention relates to a mating pair of electrical connectors including a male connector  10  and a female connector generally designated  11 . The connectors  10 ,  11 , are sometimes referred to as “quick disconnect” or plug-type connectors. The male connector  10  may be conventional, and it includes a rigid housing  12  typically formed of a hard plastic or other synthetic material including a forwardly extending plug member or extension  17  in which a plurality of male connector elements (not shown in  FIG. 1 ) are rigidly embedded. One of the male connector elements is seen in  FIG. 2  in the form of a pin, designated  14 . The connector pin  14  as well as any other connecting pins in the male connector  10  are embedded, as seen in  FIG. 2 , in a rigid, non-conducting body referred to as an “insert” and designated  15 . There may be as many as six or more contact pins in each connector, depending upon the design and function of the connector. 
         [0025]    The housing  12 , as seen in  FIG. 2 , extends forwardly (i.e., in the direction of connection of the connector  10  with connector  11 ) to include the plug member  17 , which houses the insert  15  and connector member, or pin,  14 . The insert  15  extends forwardly beyond the distal end of the plug member  17  and includes an outer peripheral extension  19  which is provided with a circumferential rim or ridge  18 , the function of which will be explained presently. A key elongated in the direction of connection, shown at  21  in  FIG. 2 , may be included on the interior of the plug extension  19  and received in a corresponding keyway on the female connector  11  (to be described), to assure proper alignment of the male connecting elements  14  with corresponding female connecting elements such as the socket  22  shown in  FIG. 2 . Each female connecting element  22  (there typically are one for each connector pin) is connected to a conducting wire  25  provided with an insulating sheath. Connectors  10  and  11  are designed to electrically connect two cables, each having a plurality of wires. As with the male connector  10 , the female connector  11  is referred to as having a “forward” portion in the direction of connection to the male connector (that is to the left in  FIG. 2 ) and a “rear” portion, which is to the right side as seen in  FIG. 2 , and remote from the male connector. As mentioned, “forward” when referring to the male (or mating) connector  10  is opposite to “forward” when referring to the female (or first) connector  11 . 
         [0026]    Referring now to the female connector  11  shown in  FIGS. 1 and 2 , it includes an outer sleeve  27  which includes a series of circumferentially spaced openings, one of which is shown at  28  in  FIG. 1 . The female connector  11  also includes an overmold  29  which covers and protects the wire  25  to which the connector  11  is connected, and also protects the interface between the connecting wires and an associated non-conducting insert  30  ( FIG. 2 ) in which the female connecting elements  22  are embedded. Again, only one female connecting element is shown for brevity and clarity, but as many as six or more separate sockets such as shown at  22  may be included in a typical quick-disconnect connector of the type shown. Both of the inserts  15 ,  30  are made of rigid insulating synthetic material as are substantially all other components of the two connectors as shown and described herein except for the connecting elements  14 ,  22 , the associated lead wires connected to connecting elements and a retainer spring, to be described. As a person skilled in the art will readily understand, other components such as the outer sleeve  27  of the female connector  11 , to be described, and the housing  12  of the male connector  10  may be made of metal for rigidity and strength. 
         [0027]    The insert  30  of the female connector  11  includes a rear section  31 A (to the right in  FIG. 2 ) and a forward section  31 B. The rear section  31 A of the insert  30  includes first and second shaped peripheral grooves  33 A,  33 B and a ridged rear section  35  for securing the overmold  29  to the female connector  11 . The overmold  29  is formed of a pliable, but strong synthetic non-conducting material. 
         [0028]    Still referring to  FIG. 2 , spaced inwardly of the outer sleeve  27  of the female connector  11  is an inner sleeve  32 , and received within the inner sleeve  32  is a spring actuator (or release sleeve, as it may be called)  34 , also in the form of a cylindrical sleeve, extending about the insert  30 . The inner sleeve  32  has a forward annular flange  33  engaging the front of the spring actuator  34 . As will be described, the inner sleeve  32  is slidable (rearwardly in  FIG. 2 ) relative to the outer sleeve  27 , and the spring actuator  34  is arranged to slide with the inner sleeve  32 , as will be described. Hence, the inner sleeve  32  and spring actuator  34  could be a single component, although it might add cost. 
         [0029]    A spring mount  37 , also having a generally cylindrical (or sleeve-like) shape, is attached to a receiving sleeve  59  of the female connector  11  and is received within the spring actuator  34 . The spring actuator  34  is also formed, generally, as a surface of revolution, and it includes an outer wall  38 . 
         [0030]    The spring actuator  34  also includes an annular forward wall  39  which lies in a radial plane and extends about the plug extension  17 , and it is then formed rearwardly into a cylindrical wall portion  42  which lies adjacent and receives the plug extension  17  of the male connector  10  when the male connector is inserted into the female connector  11 . At the right side of the inner cylindrical wall  42 , there is formed a frusto-conical lip forming an actuating wall or extension  45  which extends generally rearwardly and inwardly of the female connector  11  (that is toward the right and axially inwardly in  FIG. 2 ) and forms a spring engagement surface designated  45 A in  FIG. 2 . 
         [0031]    As seen in  FIG. 3 , the spring mount  37  receives and holds a generally circular spring member  49  which has a solid base ring  50  which extends completely around the insert  30  of the female connector  11  and is solid. The spring  49  is made of a resilient material such as beryllium or a spring steel and extending from the base ring  50  are a plurality of tines  52 . The tines  52  are spaced from one another so that they individually hinge or flex relative to the base ring  50  which forms a rigid base for the spring and which serves to mount the spring to the spring mount  37 . 
         [0032]    Referring now to  FIG. 2 , when the inner sleeve  32  is in a forward or unbiased position as shown in  FIG. 2 , the tines  52  of the spring  49  are free to move to their original position, seen in  FIG. 2 , wherein the distal or interior edges of the tines form an opening of a comparatively small diameter. In  FIG. 2 , the tines  52  are shown only partially due to the plane of the section view which is  FIG. 2 . Thus, the tines, as shown in  FIG. 2 , engage the annular rear surface  55  of the retainer ridge  18  of extension  19  of the male connector  10 , thereby securing the male plug in the connected position of  FIG. 2 . However, when the spring actuator  34  is placed in the right-hand (or release) position as shown in  FIG. 3 , the frusto-conical actuator wall  45  of the spring actuator  34  moves or bends the individual tines  52  of the spring  49  counterclockwise as seen in FIG.  2 —that is, primarily toward the right and center axis. However, in moving in such a manner, the tines  52  as a collective group move toward the right and radially outward as seen in  FIG. 2 , forming an enlarged opening permitting removal of the male connector  10  by permitting the ridge  18  of the male connector&#39;s extension  19  to be withdrawn. 
         [0033]    Still referring to  FIG. 2 , the annular extension  19  of the male insert  15  is disposed radially inward from an annular recess  54  formed in an annular receiving sleeve  59  which is an integral part of the insert  30 . Annular receiving sleeve  59  is spaced outwardly of the central plug section in order to form a receiving sleeve for the male connector  10 . A sealing O-ring  56  is received in the annular recess  54  (seen compressed in  FIG. 2 ) to form a seal with the extension  19  of the insert  15  of the male connector  10 . 
         [0034]    Turning now to the outer sleeve  27  ( FIG. 2 ), it includes a rear annular wall  58 , the innermost portion of which is comparatively thick as at  58 A so as to be located axially between the forward surface of the overmold  29  and the rear surface of a cylindrical member  62  having a cross section in a generally L shape, and forming a part of the female connector&#39;s insert  30 . It is in this manner that the outer sleeve  27  is fixedly attached to the female connector  11 . 
         [0035]    On the inner surface of the forward portion wall  26  of the outer sleeve  27  is an annular groove or recess  63 . The recess  63  receives an annular barbed portion  65  on the outer surface of the inner sleeve  32 . Comparing  FIG. 2  with  FIG. 3 , when the inner sleeve  32  is located in a forward position, as seen in  FIG. 2 , the barb  65  engages an inner surface of the forward portion wall  26  defining the inner groove  63  in the outer sleeve  27 . However, when the inner sleeve  32  is moved to the right (inserted position) as seen in  FIG. 3 , the forward peripheral flange  33  of the inner sleeve  32  engages the forward surface of the adjacent annular wall  39  of the spring actuator member  34 , moving the spring actuator  34  to the right, as seen in  FIG. 3 , thereby causing the spring engagement surface  45 A of the frusto-conical actuator wall  45  to move the tines  52  of the retainer spring  49  to the outer, or release position,—that is, free of the exterior retainer ridge  18  on the male insert extension  19 , as seen in  FIG. 3 . Thus, the inner edge portion of the tines  52  are moved into a position of increased diameter, freeing retainer ridge  18  of the extension  19  of the insert  15  of the male connector  10 , permitting the male connector to be removed from the female connector  11  as seen in  FIG. 3 . 
         [0036]    Turning now to the structure which permits actuation of the spring actuator  34  from the locking position of  FIG. 2  to the release position of  FIG. 3 , the outer sleeve  27  has a series of openings  28  ( FIGS. 1 and 4 ) spaced at equal annular increments about the outer surface of the outer sleeve. For example, there are shown three openings  28  spaced at 120° increments about the outer sleeve  27 . The straight line edge-to-edge distance between opposing sidewalls ( 66 ,  67  in  FIG. 4 ) of each of these openings  28  may be 0.157 inches. A set of four generally rectangular openings, such as those designated  74  in  FIGS. 2 ,  3 , and  4  is placed at equal annular increments about the outer surface of the inner sleeve  32 . The circumferential straight line distance of the side edges of the openings  74  may be 0.437 inches nominally. With this arrangement of openings in the inner and outer sleeves  32 ,  27 , it is highly likely that there will be alignment of at least one opening  74  on the inner sleeve  32  and one opening  28  on the outer sleeve  27 . 
         [0037]    Turning now to  FIGS. 2 and 3 , the opening  28  on the outer sleeve  27  includes a forward surface  80  and a rear surface  80 A. All of the openings on the outer sleeve include similar surfaces. All such forward surfaces in the openings  28  on the outer sleeve  27  lie in the same radial plane. These surfaces may be referred to as “reaction” surfaces, as will be appreciated from the following description. Similar reaction surfaces  83  are formed on the rear edges of each of the openings  74  on the inner sleeve  32  as shown in  FIGS. 2 and 3 . It can be seen that the axial spacing between the forward reaction surface  80  of the opening  28  in the outer sleeve  27  and the forward facing (rear) reaction surface  83  of the opening  74  in the inner sleeve  32  is arranged such that a tool such as a small blade screw driver, shown in fragmentary form at  90  in  FIGS. 2 and 3 , may be inserted in this space. This type of blade  90  has an elongated side, or edge, and a short side. The width of the screw driver blade  90  (the blade is shown only in partial form in  FIG. 2 ) is shown in  FIG. 4 . The width of the blade  90  shown in  FIG. 4  is greater than the width of its edge shown in  FIG. 2 , permitting the operator to exert considerable torque by turning the screw driver, as illustrated in  FIG. 3 . By rotating the screw driver about its longitudinal axis as shown in  FIG. 3 , the blade  90  of the screw driver axially displaces the inner sleeve  32  relative to the outer sleeve  27  and the outer opening  28  relative to the inner opening  74  because the outer sleeve  28  is engaged and maintained in fixed position on the female connector  11  by insert  30  and overmold  29  as shown in  FIG. 2 . Inner sleeve  32  is displaced to the right as shown in  FIG. 3  by the above-described rotation of blade  90  (that is, rearwardly relative to the direction of insertion for the female connector  11 ). This movement of the inner sleeve  32  rightwardly as shown in  FIG. 3  causes the spring engagement surface  45 A of actuator  34  to engage the tines  52  and move them to the release position, i.e., to the right as seen in  FIG. 3 . Rightward displacement of the inner portions of the tines  52  is limited by an adjacent surface  92  of the spring mount  37 . 
         [0038]    When the screw driver blade  90  is rotated back to its original position as shown in  FIG. 2  and removed, the action of the spring tines  49  is such as to bias the spring actuator  34  forwardly (to the left as shown in  FIG. 3 ), thereby returning the inner sleeve  32  to its initial position shown in  FIG. 1 , wherein the female connector  11  is configured for re-use. 
         [0039]    While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the relevant arts that changes and modifications may be made without the departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications that fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.