Abstract:
The invention relates to an electrical connector system including a terminal, configured to be conductively connected to a printed circuit board and a cavity body element. The cavity body element has a cavity and a primary locking member. The cavity is configured to receive the terminal. The cavity extends from a front end to a rear end of the cavity body element. The front end is arranged opposite of the rear end. The primary locking member is configured to lock the terminal. The primary locking member includes a releasing arm protruding through a lateral surface of the cavity body element.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 U.S.C. §119(a) of Patent Application No. 15161758.6 filed in the European Patent Office (EPO) on Mar. 30, 2015, the entire disclosure of which is hereby incorporated by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to an electrical connector system and a method to assemble the electrical connector system, comprising at least one terminal, configured to be conductively connected to a printed circuit board (PCB) and at least one cavity body element comprising a primary locking member to lock the terminal in the cavity body element, wherein the primary locking member has a releasing arm, protruding through a lateral surface of the cavity body element. 
     BACKGROUND OF THE INVENTION 
     Electrical connector systems are known in the art. For providing electrical conductive connections between a cable/wire and a printed circuit board, typically the printed circuit board is provided with respective pins or terminals, and a corresponding terminal is arranged on the wire, such that a pluggable connection can be provided. In typical applications, such as in the field of automotive manufacturing, a plurality of cables/wires has to be connected to a printed circuit board that is for example part of a printed circuit board-based electrical center. Those electrical centers gather several electrical connections that may be pluggable. Thus, particularly if multiple cables have to be connected, the cables can be gathered together in a harness that is provided with a multi-terminal connector. The connectors are typically limited with regard to power supply characteristics, and therefore mainly used for the signal lines. Hence, for power supply connections additional connecting facilities are required and among others, bus bars, bolts, nuts and ring terminals are commonly used. Due to the use of multiple components, and due to the complex connection of nuts and ring terminals compared to pluggable connections, known solutions for connecting the harness and the power supply to a printed circuit board are expensive and time consuming. 
     To avoid the use of bus bars, bolts, nuts and ring terminals hardwired printed circuit boards are preferred, since the terminals of the cables/wires can be directly connected to the corresponding counter terminals of the PCB by plugging. Typically, the terminals of the cables/wires are fixedly locked by corresponding locking means provided on the PCB, when firstly connected to the corresponding counter terminal. The fix locking hinders the terminals from being released, when for example being wrongly connected or for maintenance reasons. In particular the releasing of the terminals is difficult, since the terminals are typically inserted into an inlet opening of a housing of the PCB and locked therein. When installed, the cable and respectively the corresponding terminal obscures the locking means, seen from the inlet opening. Further, the outlet opening, with which the terminal is connected to the PCB is obscured by the PCB. Thus, to release the connection between the terminal and the PCB, and to remove the terminal completely, either releasing tools such as screw drivers or the like have to be used, or the PCB has to be removed first. The use of releasing tools bears the risk of damaging the PCB due to misuse and slipping. Removing the PCB requires disconnecting the entire harness and is therefore time consuming and prone to damage or destroy the PCB and/or the terminals of the PCB. 
     Thus, there is a need in the art for connecting facilities for PCBs with improved handling characteristics, in particular improved connecting and releasing characteristics, and with a secure connection and preferably a reduced number of parts. 
     BRIEF SUMMARY OF THE INVENTION 
     The problems and drawbacks related to known connecting facilities for PCBs can be overcome with an electrical connector system and a method for assembling the electrical connector system described herein. 
     In particular, the problems and drawbacks can be overcome by an electrical connector system comprising: at least one terminal, configured to be conductively connected to a printed circuit board; and at least one cavity body element, comprising a cavity and at least one primary locking member, wherein the cavity is configured to receive the at least one terminal and extends from a front end to a rear end of the cavity body element, wherein the front end is arranged opposite of the rear end, and wherein the primary locking member is configured to lock the at least one terminal, and wherein the primary locking member comprises a releasing arm, protruding through a lateral surface of the cavity body element. 
     Providing a cavity body element for receiving at least one terminal allows the plugging of the terminal on the corresponding counter terminal of the PCB, and thus a fast and easy conductive connection that is suitable for transferring signals and/or power. The cavity body element may be designed to receive one terminal, however receiving multiple terminals is also possible. The cavity of the cavity body element may be shaped characteristically, so that only one specific type of terminal can be inserted. Thus the correct connection of a cable to the PCB can be achieved. Further, by locking the received terminal, a secure connection can be achieved, since the locking renders the terminal essentially immobile and prevents the terminal from being pulled out of the cavity. 
     By providing a primary locking member comprising a releasing arm, which arm protrudes through a lateral surface of the cavity body element, the locking of the terminal by means of the primary locking member can be released easily. No additional releasing tool may be required, since the releasing arm is operable from the side of the cavity body element. Thus, hardwired PCB&#39;s can be constructed with terminals that can be safely disassembled. Further the costs of the PCB-elements, such as electrical centers can be reduced since neither complex connectors are necessary, nor additional connecting facilities such as bolts, nuts and ring terminals. 
     The primary locking member may comprise a latching protrusion configured to latch a corresponding latching recess of the terminal, to prevent the terminal from being pulled out of the cavity. Providing a latching protrusion, and in particular a latched connection between the terminal and the cavity body element, will improve the connection, so that the connection can withstand higher tensile forces, compared to non-latched connections. 
     The locking of the primary locking member may be released manually without the need of a releasing tool. A manual releasing of the primary locking member facilitates the releasing process, since no additional tool is required. For example in a manufacturing process, an operator needs not to apply a particular tool, if the locking has to be released. Thus, maintenance and failure correction can be facilitated and accelerated. Further, by avoiding releasing tools, the risk of damaging the components, such as the PCB can be minimized. 
     The locking of the primary locking member may be released by pressing the protruding releasing arm. A simple pressing for releasing the locking of primary locking member allows a fast releasing. Further, since the releasing arm is a protruding releasing arm, the releasing is operated lateral of the cavity body element and thus the releasing mechanism offers a good accessibility. 
     The cavity body element may provide an audible sound, such as a clicking sound, when the primary locking member locks the terminal. The audible sound provides a feedback for the assembling operator, indicating that the terminal is locked safely in the cavity. Thus, the assembly of the electrical connector system becomes less error-prone. 
     The cavity body element may be integrally formed with a part of the housing, covering the printed circuit board. In many applications, in particular industrial and automotive applications, printed circuit boards are covered by a housing. Forming the cavity body element integrally with the housing further reduces the number of parts of the electrical connector system. Further, a reduced number of parts significantly reduces the assembly effort. 
     The electrical connector system may further comprise a secondary locking element, wherein the secondary locking element comprises at least one blocking portion assigned to the at least one primary locking member, to prevent an unintentional releasing of the primary locking member, when the secondary locking element is engaged. Providing a secondary locking element that prevents the releasing of the primary locking member additionally secures the locking of the terminal. In particular, since the releasing of the primary locking member can be prevented, the risk of an unintentional or accidental releasing can be significantly minimized. For example, if the electrical connector system is completely assembled and integrated in e.g. an engine compartment of a car, the primary locking member could be unintentionally released during further assembly steps, in or around the engine compartment. If the locking of the terminal is released, the terminal could be pulled out of the cavity. Thus the terminal and the PCB would be disconnected, and the functionality of the e.g. on-board electronics of the car could be distorted. By preventing the releasing of the primary locking member, the risk of an unintentional releasing is minimized. 
     The secondary locking element may further comprise at least one secondary locking member, configured to additionally lock the at least one terminal. Providing further locking members additionally secures the terminal. Further, in the case that one of the primary and/or secondary locking member should fail, the other locking member provides the locking of the terminal in the cavity body element. This redundant locking system is more secure than a single locking member. 
     The blocking portion of the secondary locking element may comprise a blocking surface that contacts an outwardly oriented surface of the primary locking member in an engaging position, to prevent an outwardly directed movement (i.e. away from the cavity body element), such as bending, of the primary locking member. Typically, the primary locking member is deflected by the terminal, when the terminal is inserted into its cavity. After having passed the primary locking member during insertion, the primary locking member moves back to its initial position, to lock the terminal. To release the locking, the primary locking member must be moved again outwardly, so that the terminal can pass. If the outwardly directed movement of the primary locking member is prevented, the primary locking member has to remain in its locking position, and thus the terminal cannot pass and also remains locked. 
     The secondary locking element may further comprise a laterally protruding arm that is arranged below the releasing arm of the primary locking element, seen from the front end of the cavity body element, providing an inlet opening for the terminal. The arm of the secondary locking element may support the blocking of the outwardly directed movement of the primary locking member by blocking a movement of the releasing arm. 
     The arm of the secondary locking element may provide at least one side wall that protrudes in direction of the releasing arm of the primary locking element in an assembled condition, so that the at least one side wall protects the releasing arm may be preferably guided by the releasing arm, that is received by the at least one side wall of the arm of the secondary locking element, along the releasing arm from a pre-position in an engaging position. In the pre-position, the secondary locking element may be arranged on the cavity body element, without blocking the primary locking member and/or without locking the terminal. In the engaging position, blocking and/or locking occurs. 
     The at least one secondary locking member of the secondary locking element may comprise a secondary latching protrusion, being configured to latch into or onto corresponding secondary latching recess of the terminal, to prevent the terminal from being pulled out of the cavity. Providing a latching protrusion, and in particular a latched connection between the terminal and the secondary locking element, improves the connection between the secondary locking element and the terminal, so that the connection can withstand higher tensile forces, compared to non-latched connections. 
     The secondary locking element may be arranged moveably on the cavity body element, such that the secondary locking element is movable form a pre-position into an engaging position, and wherein the at least one secondary locking member of the secondary locking element may be guided in a guidance groove, to guide the secondary locking element form the pre-position into the engaging position. Arranging the secondary locking element movable on the cavity body element allows a faster and facilitated assembly process. Providing a preassembled structure comprising the secondary locking element and the cavity body element, reduces the number of parts to be assembled in the assembly process. Thus costs and time can be reduced. Further, providing a guidance groove facilitates the movement of the secondary locking element from the pre-position in the engaging position. Thus the movement is less error-prone. 
     The secondary locking element may further comprise at least one latching hook configured to latch a corresponding latching recess, provided on a lateral surface of the cavity body element, to secure the secondary locking element in the engaging position. Additionally securing the secondary locking element in the engaging position reduces the risk of an unintentional releasing of the locking of the terminal in the cavity body element. Since the secondary locking element, when being in in the engaging position, prevents the primary locking member from being released, and the latching hooks prevent the secondary locking element from being moved back in the pre-position, out of the engaging position, a two-step securing mechanism is achieved. 
     Further, the problems and drawbacks can be overcome by a method to assemble the electrical connector system of any of the preceding claims, comprising the following steps: providing a printed circuit board having at least one counter-terminal; providing at least one terminal; providing at least one cavity body element; aligning the cavity body element with the at least one counter-terminal of the printed circuit board; inserting the terminal through an inlet opening in the cavity of the cavity body element; and locking the terminal by means of the primary locking member of the cavity body element. Providing a cavity body element for receiving at least one terminal allows the plugging of the terminal on the corresponding counter terminal of the PCB, and thus a fast and easy conductive connection that is suitable for transferring signal and/or powers. Further, by locking the received terminal, a secure connection can be achieved, since the locking renders the terminal essentially immobile and prevents the terminal from being pulled out of the cavity. 
     The method further may comprise the following method steps: providing a secondary locking element, wherein the secondary locking element may be pre-installed in a pre-position on the cavity body element; and moving the secondary locking element in the engaging position, after the locking of the terminal by means of the primary locking element. Providing a secondary locking element additionally secures the locking of the terminal. Thus, the risk of an unintentional or accidental releasing can be significantly minimized. Further, by providing a preassembled structure comprising the secondary locking element and the cavity body element, the number of parts to be assembled in the assembly process can be reduced. Thus costs and time can also be reduced. 
    
    
     
       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 like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention. 
         FIG. 1  is a cut view of a prior art hardwired PCB; 
         FIGS. 2A-C  are cut away views of a cavity body element during the insertion and locking of a terminal according to an embodiment of the invention; 
         FIG. 3  is a view of a secondary locking element according to an embodiment of the invention; 
         FIGS. 4A , B are views of the secondary locking element of  FIG. 3  in a pre-position and in an engaging position according to an embodiment of the invention; 
         FIG. 5  is a cut away view of the electrical connector system in an engaging position according to an embodiment of the invention; 
         FIG. 6  is a cut away view of the electrical connector system, during releasing the terminal according to an embodiment of the invention; and 
         FIG. 7  is a view of an electrical connector system integrated in a housing according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a cut view of a prior art hardwired PCB  50 . The PCB  50  is provided with pins  70 ,  71 . The pin  71  is connected with a terminal  11  that is secured by means of a latching member  31 . The terminal  10  is configured to being connected with the pin  70 . Therefore it has to be inserted in the inlet opening  60  of the housing  20  that is part of the housing  40 . The housing  40  covers the PCB  50 . When inserted, the terminal  10  is secured by means of the latching member  30 . As can be seen, the releasing of the terminals  10 ,  11  is hindered, since the latching members  30 ,  31  are not accessible. Seen from the inlet opening  60 , the latching members  30 ,  31  are obscured by the terminals  10 ,  11 . Seen from the outlet opening  61 , the latching member  30 ,  31  are obscured by the PCB  50 . Thus for releasing the terminals, either a releasing tool has to be used, and/or the PCB has to be removed first, bearing the risk of damaging the PCB. 
       FIGS. 2A-C  show cut views of a cavity body element  100  according to an embodiment the invention. As can be seen in  FIG. 2A , a terminal  200  arranged on a cable  250  is partially inserted in an inlet opening  105  of the cavity  110  of the cavity body element  100 . The inlet opening  105  is provided in a front end  101  of the cavity body element  100 . A secondary locking element  300 , having a blocking portion  320  is arranged in a pre-position. The primary locking member  120 , having a latching protrusion  121  and a releasing arm  122  is elastically arranged, so that the releasing arm  122  protrudes outwardly through a lateral surface  103  of the cavity body element  100 . The primary locking member  120  is integrally formed with the cavity body element  100  and provided with some elasticity, such that it will automatically spring back into the position shown in  FIGS. 2A and 2C . 
       FIG. 2B  shows the terminal  200  even further inserted into cavity  110 . In this point of the insertion process, the terminal  200  passes the primary locking member  120 . As indicated by the arrow, the primary locking member is deflected thereby, i.e. moved outwardly, so that the terminal  200  can pass the primary locking member  120 , and in particular the latching protrusion  121 . 
       FIG. 2C  shows the terminal  200  in its final position. One can see, that it is locked by the primary locking member  120  by means of the latching protrusion  121  of the primary locking member  120  that engages with a latching recess  210  of the terminal  200 . As can be seen, the primary locking member  120  has automatically moved back in its initial position, to provide the locking. Thus the terminal  200  is locked in the cavity body element  100 . 
       FIG. 3  shows a secondary locking element  300  according to an embodiment of the invention. This secondary locking element  300  comprises a blocking portion  320  and a protruding arm  322 . The protruding arm  322  comprises two sidewalls  323 ,  324 , protruding in the direction of the releasing arm  122 , when the secondary locking element  300  is arranged in the engaging position, as can be seen in  FIG. 4B . The secondary locking element  300  further comprises a secondary locking member  330 , and two latching hooks  340 . 
       FIGS. 4A and 4B  show the secondary locking element  300  of  FIG. 3  in a pre-position ( FIG. 4A ) and in an engaging position ( FIG. 4B ). In the pre-position of  FIG. 4A , the secondary locking element  300  is arranged on the cavity body element  100 . This is a preassembled state. In the pre-position, the secondary locking element  300  does not provide any blocking or locking to the terminal  200 , so that the terminal  200  can be inserted in the cavity  110  of the cavity body element  100 . Further, the secondary locking element is arranged so that the releasing arm  122  is received by the protruding arm  322  of the secondary locking  300 . The secondary locking member  330  is received by a guidance groove  130  of the cavity body element  100 . Further, the cavity body element  100  provides a latching recess  140  on a lateral surface of the cavity body element  100  that is engageable with the latching hook  340  of the secondary locking element  300 . When the secondary locking element  300  is moved from the pre-position, as shown in  FIG. 4A  in its engaging position, as shown in  FIG. 4B , the secondary locking element  300  is at least guided by means of the guidance groove  130 . In the engaging position, the latching hook  340  engages the corresponding latching recess  140  and a corresponding guidance groove receives the other latching hook  341  on the opposite side (not visible in the  FIGS. 4A and 4B  due to the perspective). The blocking and locking functionalities of the secondary locking element  300  can be best seen in  FIG. 5 . 
       FIG. 5  shows a cut view of the electrical connector system in the engaging position of the secondary locking element  300 , as shown in  FIG. 4B . As described with respect to  FIG. 2C , the terminal  200  is locked by means of the primary locking member  120  in the cavity  110  of the cavity body element  100 . A blocking surface  325  of the blocking portion  320  of the secondary locking element  300  is in contact with an outwardly directed surface  125  (see  FIG. 6 ) of the primary locking member  120 . Thus, deflecting the primary locking member  120  outwardly is prevented. Further, in the engaging position, the secondary locking member  330  engages with a secondary locking recess  230  of the terminal  200 . Thus, a redundant locking of the terminal  200  is provided. 
       FIG. 6  shows a cut view of the electrical connector system, during releasing of the terminal  200 . As can be seen, the secondary locking element  300  has been moved back in the pre-position, so that the blocking portion  320  is no longer in contact with the outwardly directed surface  125  of the primary locking member  120 . By pressing the releasing arm  122 , as indicated by the arrow, the primary locking member  120  is moved outwardly. The latching protrusion  121  is disengaged out of the latching recess  210  of the terminal  200 . Further, the secondary locking element  300  being back in the pre-position no longer provides locking functionality, i.e. the secondary locking member  330  does no longer engage with the secondary locking recess  230  of the terminal  200 . Thus the terminal  200  is released completely, and can be pulled out of the cavity  110 . 
       FIG. 7  shows an electrical connector system arranged on a housing  400 . The housing  400  may cover the PCB  700 , to which the cable  250  is connected. A cavity body element  100  is arranged on the housing  400 , and may be integrally formed with the housing  400 . The secondary locking element  300  is arranged in the engaging position. By removing the secondary locking element  300 , or by moving the secondary locking element  300  in the pre-position, the laterally protruding releasing arm  122  becomes operable. As can be seen, the releasing arm  122  is well accessible and can be operated manually. Thus the cable  250  and the respective terminal  200  can be easily disassembled from the PCB  700 , covered by the housing  400 . 
     LISTING OF REFERENCE NUMBERS 
     
         
           1  Electrical connector system 
           10 ,  11  Terminal (prior art) 
           20 ,  40  Housing (prior art) 
           30 ,  31  Latching member (prior art) 
           50 ,  700  PCB 
           60  Inlet opening (prior art) 
           61  Outlet opening (prior art) 
           70 ,  71  Pins 
           100  Cavity body element 
           101  Front side 
           103  Lateral surface 
           105  Inlet opening 
           110  Cavity 
           120  Primary locking member 
           121  Latching protrusion 
           122  Releasing arm 
           125  Surface 
           130  Guidance groove 
           140  Latching recess 
           200  Terminal 
           210  Latching recess 
           230  Secondary latching recess 
           250  Wire 
           300  Secondary locking element 
           320  Blocking portion 
           322  Arm 
           323  First sidewall 
           324  Second sidewall 
           325  Blocking surface 
           330  Secondary locking member 
           340 ,  341  Latching hook 
           400  Housing