Abstract:
An electrical connector assembly is disclosed having an insulative housing and insulative terminal positioning assurance member. The terminal positioning assurance member has a prelatched position where corresponding latches abut, preventing inadvertent activation and locking of the terminal positioning assurance member. The terminal includes a projection which engages the terminal positioning assurance member, allowing the terminal positioning assurance member to move to a fully locked position.

Description:
FIELD OF THE INVENTION 
     The invention is directed to electrical connectors and more particularly to electrical connectors having a terminal positioning assurance member. 
     BACKGROUND OF THE INVENTION 
     In various applications of electrical connectors, devices are utilized to lock the terminals in place and to assure that they are in proper position within the electrical connector. One such field is in the automotive field where the application typically requires a so-called secondary locking system, that is, a redundant retention system for locking the terminals in place, as well as a terminal position assurance mechanism (TPA) which assures that the terminals are proper position longitudinally within the respective cavities. This prevents a proper mating of a corresponding electrical connector, where some of the lines are open due to one or more terminals not being fully loaded. 
     Certain electrical connectors are provided with housings having cavities extending therethrough for receiving terminals, each cavity provided with a resilient locking lance integrally molded with the housing for locking a terminal inserted therein. In order to further secure the terminals within the housing, it is common to provide a secondary housing member that is moveable against the locking lances to prevent the locking lances from outwardly biasing. In other words, the locking lances are blocked into their latching position. It is known to provide the secondary member pre-assembled to the housing in a pre-assembly position that allows insertion of the terminals into the connector cavities. The secondary member can then be moved to a fully locked position whereby the terminals are locked in the cavities. 
     In essence, these TPAs constitute front-loaded wedges that are shipped in a pre-stage position, which are intended to be activated, or moved into their final position, after the terminals are assembled into the housing. The TPA has a pre-locked position, but the TPA senses a partially inserted terminal, not the absence of a terminal. Traditionally, these connectors are shipped in bulk to the end user or harness maker, where the wire harnesses are made, wires crimped to the terminals, and terminals inserted into the housing cavities. Thereafter, the TPA member is moved into the final position. However, one of the difficulties with such system is that these systems tend to become locked during shipping, and the customer is left with the task of attempting to dislodge the TPA from the final locked position. 
     The objects of the invention are to improve upon the above mentioned systems. 
     SUMMARY OF THE INVENTION 
     The invention was accomplished by providing an electrical connector having a housing having at least one terminal receiving cavity extending from a rear wire entry to a front face of the housing. The housing has a front latching member extending forwardly adjacent to the front face, and the front latching member has a front leading end. A terminal positioning assurance member slidably is receivable over the front face of the housing, the terminal positioning assurance member including a rearwardly facing, flexible latch member having a rearwardly facing stop surface aligned with the front leading end of the front latch member. An electrical terminal member is also receivable into the terminal receiving cavity, the electrical terminal having a raised projection which is profiled for engaging and biasing outwardly, the rearwardly facing stop surface of the flexible latch member. The terminal positioning assurance member is held in a pre-assembled position where the rearwardly facing stop surface of the flexible latch member abuts the front leading end of the front latch member, until the terminal is inserted into the cavity to a position where the raised projection deflects the flexible latch member, and the flexible latch passes over, and locks behind the front latching member in a fully assembled position. 
     The front latching member is defined by two spaced apart walls cantilevered from the housing, with a latching bar spanning between the walls, the flexible latching member locking to the latching bar in the fully assembled position. The latching bar includes a ramped surface on a lower edge thereof, which is profiled for engaging said raised projection on the terminal. The flexible latch member is defined by a cantilevered latch arm having a ramped surfacing sloping rearwardly upwardly, the ramping surface being profiled for engaging the latching bar and assisting in the deflection on the cantilevered latch arm over the latching bar. 
     The connector further comprises cooperable latching elements on the housing and terminal positioning assurance member to latch the housing and terminal positioning assurance member in the pre-assembled position. The cooperable latching elements are comprised of a cantilevered latching arm extending from the terminal positioning assurance member, engageable with a shoulder on the housing. 
     The terminal receiving cavity has an open upper face, and the front latching member extending partially over the open upper face, and the rearwardly facing, flexible latch member extending over the open upper face from an opposite position. 
     The electrical terminal includes a forward contact area, a wire crimp section and a strain relief section, the raised projection extending upwardly from the forward contact section. The electrical terminal includes an inner contact member and an outer protective box-shaped cover, the raised projection extending upwardly from the outer protective box-shaped cover. The raised projection is comprised of a rearwardly extending ramped surface and a top surface. 
     In another aspect of the invention, an electrical connector, comprises a housing having at least one terminal receiving cavity extending from a rear wire entry to a front face of the housing, an electrical terminal member receivable into the terminal receiving cavity, and a terminal positioning assurance member slidably receivable over the front face of the housing. The housing has a front latching member extending forwardly adjacent to the front face, the front latching member having a front leading end, the terminal positioning assurance member including a rearwardly facing, flexible latch member having a rearwardly facing stop surface aligned with the front leading end of the front latch member. The terminal positioning assurance member is held in a pre-assembled position where the rearwardly facing stop surface of the flexible latch member abuts the front leading end of the front latch member, until the terminal is inserted into the cavity to a position where the terminal deflects the flexible latch member, and the flexible latch passes over, and locks behind the front latching member in a fully assembled position. 
     The electrical terminal includes a raised projection being profiled for engaging and biasing outwardly, the rearwardly facing stop surface of the flexible latch member. The electrical terminal includes a forward contact area, a wire crimp section and a strain relief section, the raised projection extending upwardly from the forward contact section. The electrical terminal includes an inner contact member and an outer protective box-shaped cover, the raised projection extending upwardly from the outer protective box-shaped cover. The raised projection is comprised of a rearwardly extending ramped surface and a top surface. 
     The front latching member is defined by two spaced apart walls cantilevered from the housing, with a latching bar spanning between the walls, the flexible latching member locking to the latching bar in the fully assembled position. The flexible latch member is defined by a cantilevered latch arm having a ramped surfacing sloping rearwardly upwardly, the ramping surface being profiled for engaging the latching bar and assisting in the deflection on the cantilevered latch arm over the latching bar. 
     The electrical connector further includes cooperable latching elements on the housing and terminal positioning assurance member to latch the housing and terminal positioning assurance member in the pre-assembled position. The cooperable latching elements are comprised of a cantilevered latching arm extending from the terminal positioning assurance member, engageable with a shoulder on the housing. 
     The terminal receiving cavity has an open upper face, and the front latching member extending partially over the open upper face, and the rearwardly facing, flexible latch member extending over the open upper face from an opposite position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the housing of the present invention, with the terminal position assurance member in a preassembled position shown poised for receipt of a contact member; 
     FIG. 2 is a perspective view similar to that of FIG. 1, showing the terminal position assurance member exploded from the housing and also shown poised for receipt of a mating connector; 
     FIG. 2A is a view similar to that of FIG. 2, showing an enlarged view of the housing and terminal position assurance member enlarged; 
     FIG. 3 is a view similar to that of FIG. 2 from a different perspective; 
     FIG. 4 is a cross-sectional view through lines  4 — 4  of FIG. 3; 
     FIG. 5 is a perspective view of a terminal for use with the present invention; 
     FIG. 6 is a perspective view of the housing and terminal position assurance member in a preassembled condition poised for receipt of a terminal and crimped wire; 
     FIG. 7 shows a perspective view similar to that of FIG. 6 showing the wire in the terminal-receiving cavity; 
     FIG. 8 shows a perspective view of the terminal deflecting a latch within the terminal position assurance member; and 
     FIG. 9 shows the terminal position assurance member in its fully locked position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With respect first to FIG. 1, an electrical connector is shown at  2  having a housing member shown generally at  4  having a terminal position assurance member  6  latched in a preassembled position, for receipt of an electrical terminal or contact member  8 . As shown in FIG. 2, the connector generally includes a forward terminal platform  10 , a rear wire entry section  12 , and a latch  14  for latching to a complementary electrical connector  16 , as will be described herein. 
     With reference now to FIG. 2A, housing  4  will be described in greater detail. As shown, the forward terminal platform  10  includes a plurality of terminal channels, such as  20   a ,  20   b  and  20   c . Each of the terminal-receiving channels  20   a  and  20   b  includes a terminal-receiving opening  22   a  and  22   b . Channel  20   c  in this embodiment is designed for receiving an alternate terminal configuration, than that of channels  20   a  and  20   b . The channels also include open upper faces  24   a  and  24   b , with the channels including rearwardly facing latching surfaces  26   a  and  26   b . Housing  4  also includes a peripheral shroud  28 , which surrounds the terminal platform  10  and latches  14  and is profiled to receive mating connector  16 . 
     With respect now to FIG. 3, housing  4  includes a plurality of rear wire openings  30 , and as shown in FIG. 4, channel  20   b  is shown extending rearwardly and intersecting a wire-receiving opening at  30   b . Wire opening  30   b  transitions to a reduced cross-section through sections  32   b  and  34   b . Section  34   b  transitions to section  36   b . As shown best in FIG. 2A, housing  4  further includes latching members  40   a  and  40   b , lying respectively over channels  20   a  and  20   b . Each of the latching members include parallel members extending forwardly from a central body portion  50  of the housing, for example, latch  40   a  includes parallel extensions  42 , with a bar portion  44  expanding therebetween. Latch  40   b  is identical to latch  40   a , and the latches are seen more clearly in the cross-sectional view of FIG.  4 . Latch  40   b  is shown with extension portion  42  extending forwardly from the central body portion  50  and with latching bar  44  in cross section. Latching bar  44  has a front leading end  46 , a ramped surface  48 , and a latching surface  52 . The front end of latch extension walls  42  also includes downwardly sloped sections  54  and a ramped surface at  56 . Furthermore, central body portion  50  includes a front edge  58  facing forwardly. 
     With respect still to FIG. 4, terminal position assurance member  6  includes a front housing portion  60 , a rearward shroud portion  62 , and a plurality of apertures  64  aligned with the respective channels  20   a ,  20   b  and  20   c . Member  6  also includes a rearwardly extending latch member  70  having a rearwardly facing stop surface  72 , a camming surface  74 , and a latching surface at  76 . Member  6  also includes a latch member at  80 , which retains the member  6  in a preassembled position and includes a ramped surface at  82  and a latching surface at  84 . Finally, member  6  includes extension fingers at  88  extending rearwardly from the body portion  60 , as will be described herein. 
     With respect now to FIG. 5, electrical terminal  8  is shown in perspective view, where the electrical terminal includes a forward contact portion  90 , an intermediate wire crimp section  92 , and a strain relief section at  94 . As should be appreciated, the electrical terminal includes a forward receptacle portion at  96 , which is profiled to receive a mating electrical terminal or pin of a mating connector. As should also be appreciated, the electrical terminal is stamped and formed from a conductive metal, such as beryllium copper, although neither the specific material nor the overall contact configuration are particularly germane to the invention. However, the terminal does include an integrally formed projection shown best at  98 , which includes a ramped surface at  100  and a top surface at  102 . 
     With respect now to FIGS. 4 and 6, the initial assembly of the electrical connector will be described. As best shown in FIG. 6, the terminal position assurance member  6  is shown in a preassembled, latched condition to the housing  4  by way of latch shoulder  84  of latch extension  80  being positioned behind latch surface  26   b  of one of the channel side walls forming cavity  20   b . It should be appreciated that the rearwardly facing latch extension  70  is centrally aligned with the latching bar  44 , which extends between opposed walls  44 . Thus, as shown in FIG. 6, in the preassembled position, surfaces  46  and  72  are shown in a substantially butting relation, where terminal position assurance member  6  cannot be moved rearwardly any further than the preassembled position. As also shown in FIG. 6, terminal  8  crimped to a wire  110  is poised for receipt within wire-receiving portion  30   b , which again is in communication with channel  20   b.    
     Continued insertion of terminal  8  causes terminal  8  to pass over transitional walls  32   b  and  34   b  to reside on channel floor  36   b . As shown in FIG. 7, this produces a prelatched position, where shoulder  104  of projection  98  is positioned behind forwardly facing edge  58  of body portion  50 . When terminal  8  passes beneath latch member  40   b , projection  98  contacts ramped surface  48 , allowing the terminal  8  to be passed therethrough. Continued movement of the terminal into the passageway causes movement of the flexible latch arm  70  upwards by way of the interaction of ramping surfaces  100  and  74 , such that the flexible latch biases into the position shown in FIG.  8 . As shown in FIG. 8, the terminal  8  is shown in the fully inserted position, and given the deflection of the flexible latch arm  70 , the terminal positioning assurance member  6  may now be moved rearwardly, such that ramped surface  74  (FIG. 8) can contact and cam flexible latch member  70  over the cross-bar portion  44  of latch  40   b . The fully latched position of the terminal positioning assurance member  6  is therefore shown in FIG.  9 . Cooperating surfaces  76  and  52  of latch  70  and cross bar  44 , respectively, retain the terminal position assurance member in the fully assembled and locked position. 
     Advantageously, both the terminals and the terminal position assurance member have prelatched conditions relative to the housing  4 , and the exact location of the terminal within the housing determines when the terminal positioning assurance member can be moved from the preassembled to the fully assembled position. Furthermore, the design is versatile as it is usable with multiple contact designs and latching structures.