Patent Publication Number: US-6666731-B2

Title: Secondary lock for a cable harness plug having different types of contacts

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cable harness plug for establishing an electric connection to a plug strip, including a housing, contact elements arranged in the housing and at least one lock, the cable harness plug including at least two different types of contacts, and a lock assigned to each type of contact, and a secondary lock for a cable harness plug of the type defined above. 
     BACKGROUND INFORMATION 
     Cable harness plugs of the type defined above may include a housing with a contact strip. The contact strip in turn includes contact elements which cooperate electrically with contact elements of a plug strip. 
     Cable harness plugs may also include different areas of contact elements, in particular when a cable harness plug is used to establish an electric connection in low as well as high power ranges. 
     In the case of a first type of contact, a contact is arranged in a chamber for establishing an electric connection to a contact element in such a manner that spring-like latch arms, which are arranged inside the contact strip, are pressed in the direction of the contact by insertion of a locking element and hold the contact in the chamber. The locking element may be inserted into the cable harness plug perpendicular to and opposite the direction of insertion of the cable harness plug. The guide elements provided on the latching element ensure that the latch arms are pressed in the direction of the contact. 
     With another type of contact, a contact is arranged in a chamber for establishing an electric connection to a contact element in such a manner that it is held in the chamber by a spring element mounted on the contact. A locking plate configured like a clamp is insertable perpendicular to the direction of plug insertion of the cable harness plug. In the locked position of this locking plate, the contact is surrounded in a clamping fashion and is thus also positioned in the correct position. 
     Due to the different configurations of contact elements, it is necessary to create a corresponding secondary lock which depends on the type of contact. It may be tedious and time-consuming to activate the secondary lock for each individual type of contact, depending on the position and arrangement of the lock. For this purpose, it may also be necessary to keep a supply of the corresponding components on hand. The injection molds for the cable harness plugs and the contact strips may be very complex in configuration and therefore cost intensive. 
     SUMMARY OF THE INVENTION 
     According to the exemplary embodiment of the present invention, secondary locking of at least two types of contacts or contact areas is provided by using one locking element. The lock includes at least one locking plate covering at least one area of one type of contact and including a locking element which, by insertion into the cable harness plug, converts the locking plate to the locked position in the one area of the type of contact and at the same time activates the lock which is assigned to the other types of contacts. 
     According to the exemplary embodiment of the present invention, simple operation, in particular of a secondary lock, is accomplished despite the fact that the cable harness plug includes different types of contacts. 
     Furthermore, due to the extraordinary retaining force of the exemplary locking plate according to the exemplary embodiment of the present invention, it is not necessary to include additional retaining elements for retaining and positioning contacts in the chambers of the contact strips. 
     According to the exemplary embodiment of the present invention, a secondary lock for a first type of contact is provided, its first part is composed of two locking plates which are movable back and forth within the cable harness plug in a direction perpendicular to the direction of insertion of the cable harness plug and which are lockable using an additional part, namely a locking element. 
     The locking plates are configured identically. They include recesses which in the locked state encompass contacts in the contact chambers. The individual locking plates overlap in the locked state. A large recess which is arranged centrally is necessary to establish the electric plug connection between the contact elements of the cable harness plug and the plug strip. 
     In one exemplary embodiment, the locking plates have a spring-like configuration which press the locking plates into their respective original positions, i.e., releasing the contacts. By insertion of the locking element, the two locking plates are converted to the locked position against the spring force. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a function diagram to illustrate the functioning of the secondary lock for a first type of contact. 
     FIG. 2 shows a top view of the locking plates of one exemplary embodiment of a secondary lock for a cable harness plug including a first type of contact. 
     FIG. 3 shows a section through a contact chamber of a cable harness plug including a contact element according to a first type of contact. 
     FIG. 4 shows a side view of a locking element as part of the exemplary secondary lock according to the present invention. 
     FIG. 5 shows a top view of the locking element according to FIG.  3 . 
     FIG. 6 shows a section through a contact chamber of a cable harness plug including a contact element according to an additional type of contact in the pre-assembly position. 
     FIG. 7 shows a section through a contact chamber of a cable harness plug including a contact element according to an additional type of contact in the locked position. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates a exemplary secondary lock  1  according to the present invention for a first type of contact. This secondary lock  1  includes two locking plates  2   a,    2   b  and a locking element  3 . 
     Locking plates  2   a  and  2   b,  shown on an enlarged scale in FIG. 2, include recesses  4  on their one outer edge. These recesses  4  cooperate with additional recesses  5  when locking plates  2   a,    2   b  are in the locked state, as illustrated in FIG.  1 . In this state, recesses  4 ,  5  extend around the contact elements arranged in chambers of a cable harness plug K. This ensures that the contact elements will be held in the correct position in the chambers. 
     To bring about the locked state, as illustrated in FIG. 1, locking element  3  are inserted into cable harness plug K. This locking element  3  includes a bottom plate  6  and guide elements  7  protruding away from bottom plate  6  like pins. On their free ends  8 , guide elements  7  include leading slopes  9  which cause locking plates  2   a  and  2   b  to move toward one another (direction of arrows  11 ) during insertion of locking element  3  into cable harness plug  1  (direction of arrow  10 ) and convert them to the locked state. 
     FIG. 3 shows a contact chamber  12  including a contact  13  arranged in contact chamber  12 . Contact  13  is held in the pre-assembly state by primary locking springs  14  in contact chamber  12 . To establish the secondary locking, both locking plates  2   a,    2   b  are pushed together so that contact  13  is surrounded by recesses  4 ,  5  of locking plates  2   a,    2   b.    
     Furthermore, clamp elements  15  (FIGS. 4,  5 ) are provided on bottom plate  6  and are used for locking another type of contact. Latch elements  20  are provided between recesses  17  and chamber  19 . These latch elements  20  are displaced initially in the direction of recesses  17  by insertion of a contact  21  to be arranged in chamber  19 , so that contact  21  may be pushed through. In a corresponding position, latch elements  20  engage behind contact  21  and hold it in chamber  19 . To prevent this latch from being released again, clamp elements  15  are to be inserted into the recesses. Due to insertion of locking element  3  in direction of arrow  16  (FIG.  6 ), clamp elements  15  penetrate into recesses  17  which are provided on the side of a contact strip  18  in the area of respective chambers  19 , blocking movement of latch elements  20  in the direction of recess  17 . This secures the latching of contact  21  in chamber  19 . 
     FIG. 7 shows this latched position. The clamping effect of this device is so strong that the above-mentioned primary lock/primary locking spring  14  (FIG. 3) may be omitted. 
     Locking element  3  includes a corresponding number of clamp elements  15  and guide elements  7 , depending on the configuration of the contact strip. 
     Due to the configuration of this secondary lock, the locking of elements is accomplished with a single locking element, the lock is assigned to different types of contacts.