Patent Publication Number: US-9425534-B2

Title: Lever-type electrical connector with connector positioning assurance member

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 U.S.C. §119(a) of patent application Ser. No. 14/190,516.6 filed in the European Patent Office (EPO) on Oct. 27, 2014, the entire disclosure of which is hereby incorporated by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to an electrical connector assembly with a secondary locking device, and in particular wherein the electrical connector assembly allows for direct mating and unmating of a plug connector to a corresponding counter connector. 
     BACKGROUND OF THE INVENTION 
     The safe coupling of connectors is of high importance for many applications. For example, modern passenger cars comprise a variety of different electrical connections. For ensuring that connectors mated with a corresponding counter connector cannot become loose unintentionally, secondary locking members are known in the art to guarantee a safe mechanical coupling between the connector and counter connector. 
     Further on, it is also desirable to indicate, either visually or physically, that a plug connector has been fully and properly mated with a corresponding counter connector during the assembly procedure for allowing a “fool proof” assembly. In order to reduce the risk associated with improperly mated connectors, so-called connector position assurance (CPA) devices have been developed. Such CPA devices are separate elements, which can be inserted into a connector housing of a plug connector and are often provided in a different color. When the connector is not properly or fully coupled to its corresponding counting connector, the CPA device cannot be fully inserted into the connector housing. Accordingly, the CPA device protrudes from the connector, indicating that full mating has not been accomplished yet. Only upon full and proper mating of the connector with the counter connector it is possibly to fully insert the CPA device into the connector housing. This allows to visually indicating whether the plug connector has been properly and correctly mated with the counter connector. Often, the functionalities of CPA devices and secondary locking devices are integrated in one part. 
     Accordingly, the commonly used mating procedure requires several steps. The connector has to be mated with a counter connector, and also locked thereto. Further, a secondary lock has to be closed and/or a CPA device has to be inserted to assure the proper mating. However, in modern manufacturing sites, it is often desired that a plug connector is mated with a counter connector in a fast and secure manner. This need arises among others for ergonomic reasons. Hence, it is desired that the mating procedure can be accomplished with a minimal number of steps. 
     The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the present invention there is provided an electrical connector assembly, which comprises a plug connector. This plug connector comprises a connector housing having a flexible leg (i.e. one or more) with a primary locking device provided thereon. The primary locking device is adapted to provide a primary locking function when the plug connector is mated with a corresponding counter connector. The primary locking device is provided such that when the flexible leg of the connector housing is flexed, the primary locking function can be disengaged. 
     The plug connector further comprises a secondary locking device which is arranged moveable relative to the connector housing between an open position and a closed position. In the open position, it allows a mating of the plug connector with a counter connector and in the closed position it provides for an additional (secondary) locking between plug connector and counter connector. To this end, the secondary locking device comprises a flexible arm and at least one jamming portion. The jamming portion can be part of the flexible arm of the secondary locking device. Preferably, however, the jamming portion is an element which is separate from the flexible arm. This is advantageous, since it allows designing the jamming portion with a high rigidity and the flexible arm with a low rigidity, i.e. increased flexibility. 
     The flexible leg of the connector housing and the flexible arm of the secondary locking device are adapted to be in blocking contact when the flexible arm of the secondary locking device is not flexed. In other words: in the idle, not stressed or engaged configuration of the flexible arm the secondary locking device cannot be moved in the blocked direction, which preferably is the mating direction. This blocking contact inhibits in particular movement of the secondary locking device from the open position into the closed position. In other words, the flexible arm of the secondary locking device needs to be flexed in order to move the secondary locking device from the open position into the closed position. This has the advantage that an operator can push the plug connector into the mated position via the secondary locking device, e.g. by applying pressure onto the secondary locking device itself. Thereby, a so-called inertia locking functionality can be achieved. 
     Further on, the flexible arm of the secondary locking device is adapted to be flexed when the plug connector is mated with the corresponding counter connector. Accordingly, when the plug connector is mated with the counter connector, the flexible arm is flexed such that the secondary locking device can be moved into the closed position. Preferably, the arm is automatically flexed due to e.g. a (direct or indirect) contact with a portion of the counter connector. This is advantageous, since upon full mating, the secondary locking device is thus automatically released and can be pushed in its locked position. 
     When the secondary locking device is in the closed position, the jamming portion of the secondary locking device is adapted to prevent a flexing of the flexible leg of the connector housing. In other words, the primary locking function of the flexible leg of the connector housing cannot be disengaged when the secondary locking device is in the closed position, because the jamming portion prevents a flexing of the flexible leg which could otherwise disengaged the primary locking function. Thereby, a second locking is provided to the connector system. 
     Hence, the design of the electrical connector assembly according to the present invention allows for a straightforward mating process. Since the secondary locking device is released by pushing it in mating direction, the secondary locking device can be automatically closed in one single work step when mating the plug connector with the counter connector. The inertia involved in the mating process, when an operator pushes the plug connector via the secondary locking device with considerable force, has the effect that the secondary locking device is automatically closed by the operator, when the applied force is sufficient for mating. This particularity is also denoted as “inertia locking”. The interaction of the secondary locking device with the connector housing thereby provides in addition a connector position assurance (CPA) functionality, allowing for a direct verification of a successful and complete mating. 
     The term “counter connector” used herein denotes any kind of connector adapted to connect to the plug connector. Furthermore, the terms “flexible leg” and “flexible arm” used herein are not limiting to a particular appearance or structure, however, both elements should not be stiff, i.e. rigid. For example, the flexible leg can be present in form of a plate-like element, while the flexible arm can be in the form of a ring-like structure instead. Preferably, the flexible leg and the flexible arm are of a rod-like or bar-like form, extending parallel to the mating direction. 
     As mentioned above, preferably, the direction of movement of the secondary locking device from the open position to the closed position is the same or approximately the same as the mating direction of the plug connector to the corresponding counter connector. Further preferred, the plug connector can be fully coupled to the corresponding counter connector by means of inertia locking. The skilled person understands that inertia locking implies that the whole coupling procedure is performed in one step, and the operator cannot stop at an intermediate coupling state. In other words, when starting the coupling procedure and overcoming a first barrier with a certain force, the coupling procedure is continued due to inertia until the plug connector is fully coupled to the corresponding counter connector. The term “fully coupled” thereby means that the plug connector is mated with the corresponding counter connector and the secondary locking device is in the closed position, thereby providing CPA functionality. Accordingly, due to the inventive design, it is possible to mate and unmate plug connector and corresponding counter connector in a direct and straightforward manner, requiring only a single action of the operator. 
     In a further preferred embodiment, the flexible arm of the secondary locking device comprises a T-shaped or L-shaped portion and the flexible leg of the connector housing comprises at least one projection. Preferably, when the plug connector is not mated with the corresponding counter connector, any forces acting in mating direction onto the secondary locking devices are transferred in longitudinal direction along the flexible arm, which is not flexed, onto the connector housing via the blocking contact between the T- or L-shaped portion and the projection. Accordingly, the interaction between the T- or L-shaped portion and the projection of the connector housing inhibits the movement of the secondary locking device from the open position into the closed position when the plug connector is not mated with the corresponding counter connector. Since the forces are transferred in longitudinal direction along the flexible arm, the flexible arm can withstand relatively high forces without being deformed or breaking. 
     In a further preferred embodiment, the secondary locking device comprises a release portion which is adapted to flex the flexible leg of the connector housing when a secondary locking device is moved from the closed position to the open position. Due to this flexing of the flexible leg, the primary locking function is disengaged and the plug connector can be unmated and removed from the corresponding counter connector. 
     In a further preferred embodiment, the connector housing comprises guiding means which guide the movement of the secondary locking device between the open and closed position. Preferably, the guiding means comprises a recess such that the secondary locking device can be rotated at least partially around an axis perpendicular to the mating direction. Due to this rotation, the secondary locking device interacts with the flexible leg of the connector housing such that the flexible leg is flexed and the primary locking function is disengaged. Accordingly, by rotating the secondary locking device, an operator can disengaged the primary locking function and unmate the plug connector from the corresponding counter connector with minimal effort. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  illustrates a plug connector in a fully disassembled state according to one embodiment; 
         FIG. 2  illustrates the plug connector of  FIG. 1  in a fully assembled state according to one embodiment; 
         FIG. 3  illustrates a partially cut view of a partially assembled plug connector according to one embodiment; 
         FIG. 4  illustrates a secondary locking device according to one embodiment; 
         FIG. 5  illustrates a partially cut view of the plug connector of  FIG. 2  according to one embodiment; 
         FIG. 6  illustrates a partially cut view of the plug connector of  FIG. 2  mated with a corresponding counter connector according to one embodiment; 
         FIG. 7  illustrates a partially cut view of the plug connector of  FIG. 6  fully coupled to the corresponding counter connector according to one embodiment; 
         FIG. 8  illustrates a partially cut view of the assembly of  FIG. 6  in another configuration according to one embodiment; and 
         FIGS. 9 through 11  illustrate partially cut side views of a plug connector according to the present invention according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It is therefore an object of the present invention to provide an electrical connector assembly which allows for a fast and secure mating of a plug connector with a counter connector. It is an additional object of the present invention to provide an electrical connector assembly which allows for an easy unmating procedure without increasing the risk of an unwanted release of the connector from the counter connector. 
       FIG. 1  presents the components of a plug connector according to the present invention, namely a connector housing  10 , a secondary locking device  20 , a terminal position assurance (TPA) member  30 , and a sealing member  40 .  FIG. 2  illustrates the plug connector of  FIG. 1  in an assembled state. The skilled person understands that the TPA member  30  and sealing member  40  are optional components, which are preferably utilized in order to improve the functionality of the plug connector. 
       FIG. 3  illustrates the connector housing  10  with TPA member  30  and sealing member  40  attached thereto. The connector housing  10  comprises two flexible legs  11   a ,  11   b , which support a primary locking device  13 , which in turn is present in form of a latch. The latch is adapted to interact with a corresponding counter connector  50  in order to lock the connector housing  10  thereto. The flexible legs  11   a ,  11   b  further comprise two projections  12   a ,  12   b  and jamming surfaces  14   a ,  14   b . The projections  12   a ,  12   b  and jamming surfaces  14   a ,  14   b  are both provided on the same, upper side of the flexible legs  11   a ,  11   b . Opposing the jamming surface  14   a , there is provided an unlocking portion  15   a . Although not visible, the skilled person understands that a similar unlocking portion is provided opposing the jamming surface  14   b  provided on flexible leg  11   b , as the illustrated connector housing  10  (and also the secondary locking device  20 ) is mirror-symmetric. 
       FIG. 4  illustrates the secondary locking device  20  featuring a flexible arm  21 , which in turn features a secondary locking means at one end thereof, which is adapted to interact with a corresponding counter connector  50 . The skilled person understands that the secondary locking device  20  and also the connector housing  10  can have any number of flexible arms  21  and flexible legs  11 , respectively. 
     The flexible arm  21  features a T-shaped portion  22   a ,  22   b  with lateral extensions away from the flexible arm  21 . Alternatively, the flexible arm  21  could also be provided with an L-shaped portion, however, the T-shape allows due to its symmetric design a more homogenous transfer of forces. Further on, the secondary locking device  20  comprises two jamming portions, of which only one jamming portion  24   b  is visible in  FIG. 4  due to the perspective. Further on, the secondary locking device  20  features two release portions  25   a ,  25   b  adapted to interact with the unlocking portions  15   a ,  15   b  of the connector housing  10  as will be described as follows. 
     The secondary locking device  20  is provided with a relatively large actuating surface  29 , allowing for a simple operation. Further on, the secondary locking device  20  features an actuating portion  28 , which allows for inserting for example a screw driver and moving the secondary locking device  20  therewith. 
     As can further be seen in  FIG. 4 , the secondary locking device  20  features at least one protrusion  26   a  adapted to interact with retention means, such as the retention means  16   b  (as mentioned, the secondary locking device  20  is symmetrical, so that it is in fact the symmetrical retention means opposite the retention means  16   b ), provided in form of a wedge on the connector housing  10 , such that the secondary locking device  20  cannot be fully removed from the connector housing  10 . It is generally preferred that the movement of the secondary locking device  20  is constrained to between an open and closed position, so that it cannot become unintentionally loose. Further on, the secondary locking device  20  features a feedback portion  27   a , which passes by a respective retention means  16   a  provided on connector housing  10  (not visible in  FIG. 4  due to the perspective, but analogous to retention means  16   b ) such that a portion of the secondary locking device  20  is deflected and subsequently attracted, thereby producing an acoustic feedback signal indicating that the mating process has succeeded. 
       FIG. 5  illustrates the assembly of  FIG. 3  with the secondary locking device  20  of  FIG. 4  attached thereto, whereby the secondary locking device  20  is in its open position. The guiding means  17   b  of the connector housing  10  thereby restrict the direction of movement of the secondary locking device  20  to be approximately the same as the mating direction of the entire plug connector. 
     In the configuration of  FIG. 5 , the jamming surfaces  14   a ,  14   b  of the connector housing  10  are not covered by the jamming portions  24   b  of the secondary locking device  20 . Further on, the blocking contact of the T-shaped portions  22   a ,  22   b  with the projections  12   a ,  12   b  of the connector housing  10  prevent a movement of the secondary locking device  20  further into the connector housing  10 . In other words, when pushing on actuating surface  29 , the resulting forces are transferred via the flexible arm  21  of the secondary locking device  20  in longitudinal direction of the flexible arm  21  to the T-shaped portion  22   a ,  22   b  and finally to the connector housing  10 . Due to the symmetric arrangement of the T-shaped portion  22   a ,  22   b  and the orientation of the flexible arm  21 , the forces are efficiently transferred without inducing damages to the secondary locking device  20 . 
       FIG. 6  shows the plug connector of  FIG. 5 , whereby the connector housing  10  is mated with the corresponding counter connector  50 . During the mating procedure, a counter-locking means  51  provided on the counter connector  50 , preferably being in form of a bulge, flexes the flexible legs  11   a ,  11   b  of the connector housing  10  such that the primary locking device  13  of the connector housing  10  can be positioned on the other side (behind) of the counter-locking means  51 . The same counter-locking means  51  is adapted to interact with the secondary locking means  23  of the secondary locking device  20  such that the flexible arm  21  is flexed upwardly (in the orientation of  FIG. 6 ) and the blocking contact present between the T-shaped portions  22   a ,  22   b  and projections  12   a ,  12   b  is cancelled, so that the secondary locking device  20  can now be further inserted into the connector housing  10 , e.g. by pushing in mating direction onto actuating surface  29 . 
       FIG. 7  shows the plug connector of  FIG. 6  fully coupled to the corresponding counter connector  50 . As can be seen, the T-shaped portions  22   a ,  22   b  are now positioned behind the projections  12   a ,  12   b  of the connector housing  10  as seen in mating direction. Further on, the jamming portion  24   b  is now positioned such that it covers the jamming surface  14   b  of the flexible leg  11   b  of the connector housing  10  at least partially. Accordingly, since the jamming portion  24   b  is a rigid element, the flexible leg  11   b  of the connector housing  10  cannot be flexed. Hence, the full insertion of the secondary locking device  20  into connector housing  10 , as illustrated in  FIG. 7 , indicates to the operator that (i) the connector housing  10  is mated with the corresponding counter connector  50 , (ii) the primary locking device  13  of the connector housing  10  is properly positioned with respect to the counter-locking means  51  of counter connector  50  to provide primary locking function, (iii) the secondary locking means  23  is positioned to support the secondary locking functions, and (iv) the jamming portion  24   b  is arranged such that the primary locking function of the connector housing  10  cannot be disengaged. Further, one can see that a step  201  is provided on the guide walls of the secondary locking device  20 . The step  201  facilitates the rotation of the secondary locking device  20  as will be explained in more detail below. 
       FIG. 8  illustrates the plug connector of  FIG. 7  mated with the counter connector  50  but before the secondary locking device  20  is in the open or initial position. As can be seen, the jamming portion  24   b  is not covering the jamming surface  14   b  of the flexible leg  11   b  of connector housing  10  any longer. In addition, the T-shaped portions  22   a ,  22   b  are again on the outer side of projections  12   a ,  12   b  and the secondary locking function is disengaged. Furthermore, the release portion  25   a  is now in contact with unlocking portion  15   a  provided on flexible leg  11   b  of the connector housing  10 . When the secondary locking device  20  is further removed from the connector housing  10 , the release portion  25   a  interacts with unlocking portion  15   a  such that the flexible legs  11   a ,  11   b  of connector housing  10  are flexed. Since the jamming portions  24   b  are not covering the jamming surfaces  14   a ,  14   b  any longer, this flexing is not blocked. Preferably, the release portion  25   a  and/or the unlocking portion  15   a  is provided in form of a ramp, as illustrated, such that both portions can be in force-fitted contact with each other, allowing for a flexing of the flexible legs  11   a ,  11   b  without having to apply large forces. 
     In a further preferred embodiment, as illustrated in  FIG. 9 , the guiding means  17   b  of connector housing  10  comprises a recess  18   b , alternatively characterized as a gap, and the corresponding wall of the secondary locking device  20  comprises a step  201 . The recess  18   b  is provided such that when the secondary locking device  20  is not in the closed position, it can be rotated such that the recess  18   b  receives the secondary locking device  20  at least partially. This configuration is illustrated in  FIG. 10 . The step  201  allows the rotation only when the secondary locking device  20  is pulled into the position of  FIGS. 9 and 10 , where the secondary locking device  20  is pulled further outwards away from the initial or open position shown in e.g.  FIG. 8 . Due to this rotary or angled motion, and due to the simultaneous contact of unlocking portion  15   a  with release portion  25   a , the flexible leg  11   a ,  11   b  of connector housing  10  can be flexed by pushing onto the outer end of secondary locking device  20  as indicated by the arrow in  FIG. 10 . This movement is particularly ergonomic for the user. The secondary locking device  20  is thus used as a lever facilitating the unmating process. Due to this flexing motion, the primary locking device  13  is released from the respective counter-locking means  51  provided on counter connector  50  such that the plug connector can be removed from the counter connector  50  with minimal effort. 
     The depth of the recess  18   b , which can receive the secondary locking device  20  at least partially, is in the range of 0.1 to 2.5 millimeters (mm), preferably in the range of 0.3 to 2.0 mm, more preferably in the range of 0.3 to 1.5 mm and most preferred in the range of 0.4 to 0.6 mm. With reference to  FIG. 11 , the connector housing  10  can comprise one or more hooks  19  which are adapted to interact with the secondary locking device  20  such that it cannot be fully removed from the connector housing  10 . 
     While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. Moreover, the use of the terms first, second, etc. does not denote any order of importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items. 
     LIST OF REFERENCE NUMERALS 
     
         
           10  connector housing 
           11   a ,  11   b  flexible leg 
           12   a ,  12   b  projection 
           13  primary locking device 
           14   a ,  14   b  jamming surface 
           15   a  unlocking portion 
           16   b  retention means 
           17   b  guiding means 
           18   b  recess or gap 
           19  hook 
           20  secondary locking device 
           21  flexible arm 
           22   a ,  22   b  T-shaped portion 
           23  secondary locking means 
           24   b  jamming portion 
           25   a ,  25   b  release portion 
           26   a  protrusion 
           27   a  feedback portion 
           28  actuation portion 
           29  actuation surface 
           30  terminal position assurance member 
           40  sealing member 
           50  counter connector 
           51  counter-locking means 
           201  step