Abstract:
A connector assembly has mating first and second electrical connectors and a holder in which the mated connectors are adjustable in an axial direction. The holder secures the first connector in a first position wherein electrical terminals within the first connector are engaged with shorting contacts in the holder. The first connector is held in this position while the second connector is pushed into the holder and mated with the first connector, causing terminals within the second connector to be brought into electrical connection with the terminals in the first connector and releasing the first connector from the holder securement. Further pushing of the second connector into the holder locks the connectors together and moves the mated connectors as a unit to a second position within the holder. Simultaneously, parts of the first connector force the shorting contacts out of electrical connection with the terminals. These parts exert a wiping action on the shorting contacts. When the connectors need to be separated the first and second connectors are moved as a unit back to the first position. The shorting contacts are reengaged with the terminals in the first connector before the connectors are electrically disconnected.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to electrical connectors and more specifically to mating connectors that include shorting bars to protect the circuits. 
     2. Discussion of Related Art 
     Shorting bar systems have been employed on vehicle safety devices such as airbags, seat restraints and ABS brakes. For example, in airbag connectors, the shorting bars short circuit the triggering circuit by shorting the female terminals in the female connector to each other if the connectors are inadvertently disconnected or intentionally disconnected for maintenance or testing purposes. Since these are generally low current components, there can be a buildup of oxidation on the electrical contacts, causing electrical discontinuity in the circuits. Often, in the assembly process, the electrical connections in these safety devices are made by hand because of the fragility of the components and the relative complexity of the assembly process. With the continued automation of automotive assembly lines, modular assembly of these devices has become necessary. 
     Typically, a mating electrical connector disconnects the short. A female connector housing has female terminals and shorting bars. The shorting bars are shaped and spring biased to be in electrical engagement with the female contacts. A male connector housing has male contacts and engagement posts. When the connector housings are mated, the male contacts are mechanically and electrically connected to the female contacts. The engagement posts of the male connector housing disengage the shorting bars from the female contacts, eliminating the short circuit and making the connector assembly fully operational. 
     In many cases, oxidation can occur on the shorting bar contact surfaces, affecting the reliability of the short connection with the terminals. The engagement posts are often thin and short, and inaccuracies in length and position caused by the molding process may cause them to miss or ineffectively deflect the shorting bars. In addition, there is typically nothing to protect the mated connectors in vehicle areas such as engine compartments. If they are jostled or collide with other vehicle components, the male and female connectors can shift or vibrate relative to each other. This can damage the terminals and cause them to wear on each other. Fretting corrosion, which occurs when parts of the terminal plating flake off and oxidizing takes place on the exposed terminal surfaces, is not uncommon. However, if the electrical connection process becomes more complex when these problems are addressed, there is a risk that assembly can no longer be automated. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of this invention to ensure positive contact between male and female terminals in mating connectors prior to disconnect of a safety short, and to ensure the safety short is reconnected before the terminals are unmated. 
     A further object of the invention is to enable the connector assembly to be axially adjustable as a unit so connectors of the assembly do not move relative to each other. 
     Another object of the invention is to provide a simple, reliable shorting system for a fully automated modular connector assembly. 
     In carrying out this invention in the illustrative embodiment thereof, a holder is used to secure a female connector in a first position. The holder has shorting contacts. The female connector has slots through which the shorting contacts engage female terminals within the female connector in the first position. There are cam surfaces at ends of the slots. When a male connector is inserted into the holder, the female connector remains in the first position until the connectors are fully mated with male terminals in the male connector in electrical engagement with the female terminals. Further insertion of the male connector releases the female connector from the first position and locks the connectors together. The connectors move together as a unit to a second position. Simultaneously, the cam surfaces push the shorting contacts out of the slots, enabling functional operation of the connectors. Any forces pushing or pulling on the connectors cause them to move as a unit in an axial adjustable direction within the holder, preventing damage to and reducing wear on the terminals and allowing for manufacturing tolerances, until the connectors are secured in a required position by, for example, locking tabs on the male connector. 
     When it is desired to break the electrical connection and separate the connectors, the connectors are pulled or pushed back to the first position within the holder. The female connector again becomes locked in the first position by the holder as the shorting contacts reengage the female terminals. Further removal force on the male connector then separates the connectors and takes the male connector out of the holder. Operation of the shorting contacts and holder and connector locks is achieved simply by movement of the connectors axially within the holder, so the assembly and disassembly of the connectors can be fully automated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention, together with other objects, features, aspects and advantages thereof, will be more clearly understood from the following description, considered in conjunction with the accompanying drawings. 
     FIG. 1 is a perspective view of a holder and female connector prior to assembly. 
     FIG. 2 is a perspective view of the assembled holder and female connector. 
     FIG. 3 is a perspective view of the assembled holder and female connector and a male connector positioned for engagement with the assembly. 
     FIG. 4 is a perspective view of the assembled holder and female connector and a male connector with a male terminal positioned for electrical engagement. 
     FIG. 5 is a perspective view of the male connector assembled into a first, short-active position with the holder and female connector. 
     FIG. 6 is a perspective view of the male connector assembled into a second, short-disconnected position with the holder and female connector. 
     FIG. 7 is a cross-sectional side view of the male and female connectors in mating engagement within the holder with shorting bars in contact with female terminals. 
     FIG. 8 is a cross-sectional side view of the mated male and female connectors with the shorting bars pushed out of electrical contact with the female terminals. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, the female half of the connector assembly of the present invention is illustrated. The female half of the connector assembly could be snapped into a vehicle panel using conventional panel locks or could be used simply as an in-line connection. A holder  12  comprises side walls  14 , a bottom wall  16 , a top wall  18 , an open first end  20  and an open second end  22 . The side walls  16  each include a substantially rectangular aperture  24  in which a lock arm  26  is formed. The lock arm  26  has a first end  28  integral with the side wall and extending from adjacent the holder second end  22 . The lock arm  26  has a second, free end  30  with a pawl  32  projecting into an interior of the holder. Since the apertures are relatively large, braces  34  extend across the apertures and provide stability to the side walls. The braces jut away from the side walls because of tooling requirements in molding the lock arms. Stop blocks  36  protrude from the top, bottom and side walls part way into the interior of the holder adjacent the first end  20 . 
     The top and bottom walls of the holder each have a shorting bar  38  extending across the walls from side wall to side wall. The shorting bars  38  each have a plurality of flexible contacts  40  curved and spring-biased to extend into the interior of the holder in the direction of the holder second end  22 . 
     A female connector  50  has an electrically insulative housing comprising two side walls  52 , upper wall  54  and lower wall  56 . The housing has an interior body  58  including a plurality of terminal accommodating chambers  60  for receiving female electrical terminals. Narrow slots  62  in the upper and lower walls communicate with the chambers  60 . The connector  50  has an insertion end  64  for insertion into the holder  12  and an opposite female terminal receiving end  66 . Projecting from the side walls over portions of the upper and lower walls are guide rails  68 . The side walls further include channels  70  extending from the female terminal receiving end  66  and ending at chamfered latch edges  72  on cross-pieces  74 . The cross-pieces  74  are cantilevered on the side walls so they can flex relative to the interior body  58 . 
     The insertion end  64  of the female connector  50  is pushed into the holder  12  through the second end  22  of the holder. The guide rails  68  of the connector housing are guided by inside surfaces of the holder walls to provide smooth, correct assembly. The shorting contacts  40  are deflected toward the holder upper and lower walls by the connector body  58 . The lock arms  26  of the holder follow the channels  70  of the female connector  50  until the pawls  32  are lifted by the crosspieces  74  and then drop into the channel. The slots  62  have beveled termination or cam surfaces  76  at their ends or extremities spaced inward along the body  58  a short distance from the insertion end  64  of the female connector. The distance is set such that the shorting contacts  40  drop into the slots  62  just prior to when the ends of the guide rails  68  of the connector abut against the stop blocks  36  of the holder. The assembled holder  12  and female connector  50  are shown in FIG.  2 . In the assembled condition, the contacts  40  of the shorting bars  38  extend through the slots  62  of the female connector into the terminal accommodating chambers  60 . If an attempt is made to remove the female connector from the holder, the pawls  32  press against the latch edges  72 . Further insertion movement of the female connector is prevented by the force of the holder stop blocks  36  against ends of the guide rails  68  of the connector. Therefore, the female connector  50  is held in a first, short-active position within the holder  12 . It can only be removed by manually lifting the pawls  32  out of the channels  70  and sliding the connector in a reverse direction. 
     FIG. 3 shows the assembled holder and female connector from the perspective of the holder end  22 , as well as a male connector  80  positioned for mating with the female connector  50 . The male connector comprises an electrically insulative housing having side walls  82 , an upper wall  84  and a lower wall  86 . A main body  88  of the housing includes terminal accommodating chambers  90  for receiving male electrical terminals through a male terminal receiving end  92 . The body terminates approximately half-way along the side walls  82  at an opposite mating surface  94 . Formed on the side walls  82  are guide wings  96 , giving each side wall a u-shaped extension defining an open interior space  98  of the housing beyond the body  88 . On an outer surface of each side wall and wing is a continuous groove  100  with a ramp projection  102  protruding from the groove and outer surface of the wing adjacent an insertion end  104  of the male connector  80 . The ramp projections have opposite forward and rearward angled operating surfaces  106  and  108 , respectively, with the rearward operating surface  108  having a slightly steeper angle. 
     The holder and connector housings may be molded from an electrically insulative plastic, for example polybutylene terapthalate. The shorting bars may be stamped and bent from an electrically conductive metal, insert-molded or press-fitted into the holder. The male and female connectors are used only for illustration purposes. For example, the holder may be used to first receive a male connector to hold in the first position for later mating with a female connector. The words top, bottom, upper, lower and side are used only to describe the invention as illustrated by the drawings. The holder and connectors may be in any spatial orientation. 
     As the insertion end  104  of the male connector  80  is pushed in through the open first end  20  of the holder  12 , the guide wings  96  of the male connector slide under the side walls  52  of the female connector  50 . The forward operating surfaces  106  of the ramp projections  102  on the guide wings lift the cross-pieces  74  of the female connector side walls. Further insertion movement causes the ramp projections  102  to lift the pawls  32  on the ends  30  of the holder lock arms  26 . The cross-pieces  74  then drop back down behind the rearward operating surfaces  108  of the ramp projections, securing the male and female connectors in a fully mated condition. However, pawls  32  of the holder lock arms  26 , having been pushed away from the latch edges  72 , no longer hold the female connector in the first position. At this short-active first position the male and female connectors are engaged and the male and female terminals within the male and female connectors, respectively, are electrically mated. Further pushing of the male connector causes the two connectors to axially move within the holder toward the end  22  of the holder to a second position wherein the shorting contacts  40  of the holder are disconnected from the female terminals within the female connector. 
     FIG. 4 illustrates the assembled holder and female connector from a different perspective, along with the male connector. This figure includes a representation of a male terminal  110 , demonstrating how it extends from the body  88  of the male connector  80  into the interior space  98  for eventual insertion into a terminal accommodating chamber  60  of the female connector  50 . Also illustrated in FIG. 4 is an example of an optional bracket  112  on the male connector for possible attachment to a vehicle body panel after the connectors have been mated and moved to the second, short-disconnected position. 
     FIG. 5 shows the male connector  80  as it approaches full mating with the female connector  50  in the holder  12  but still in the first position. The short is still active because of the continued engagement of the short contacts  40  with the female terminals in the female connector through the slots  62 . FIG. 6 illustrates the second, short-disconnect position of the mated connectors. The pawls  32  of the holder lock arms  26  have been released from the latching edges  72  of the cross-pieces  74  of the female connector side walls  52 , allowing the mated connectors to move to the second position. 
     FIGS. 7 and 8 demonstrate the movement of the mated connectors from the first to second positions within the holder in more detail. A single conventional male electrical terminal  110  is shown in the male connector  80  and a single female conventional electrical terminal  114  is shown in the female connector  50  for demonstration purposes. The terminated electrical wires are not shown for simplicity. Conventional locks  116  and  118  secure the female and male terminals in their respective connectors. It should be understood that the invention concept can be used for connectors having any number and type of terminal accommodating chambers, terminals and shorting contacts or systems, including systems wherein the terminal or terminals are shorted to a vehicle ground. 
     FIG. 7 illustrates the first position, corresponding to FIG. 5, wherein the male and female connectors are fully mated and the male terminal  110  and female terminal  114  are in electrical engagement. The shorting contacts  40  are still in electrical engagement with the female terminals through the slots  62  of the female connector. The mating surface  94  of the male connector  80  is pressed against the end  64  of the female connector  50 . 
     Further insertion force on the male connector moves the mated connectors to the second position, as shown in FIG.  8 . The shorting contacts  40  are cammed out of the slots  62  by the beveled termination or cam surfaces  76  of the slots adjacent female connector end  64 . The short is thereby disconnected. The shorting contacts cannot be disconnected until the connectors are fully mated. This ensures that the terminals are electrically engaged before the short is disconnected. Movement of the assembled connectors beyond the second, short-disconnected position can be arrested by the securement of the male connector bracket to a panel, for example. If the assembly is used in an in-line system, stops can be formed on the male connector to contact the holder  12 . The point is to allow axial adjustment of the mated connectors as a unit, without relative movement between the connectors. The second position can be a range of positions in which the short is disconnected. 
     As the male connector is pulled out of the holder in a reverse movement, the female connector returns to the first position within the holder. The shorting contacts drop back down into the slots  62  to again engage the female terminals before the connectors are unmated because movement of the female connector with the male connector is not arrested until the female connector ends of the guide rails  68  again abut the stop blocks  36  of the holder. The operating surfaces  108  of the ramp projections  102  on the male connector press against the latch edges  72  on the female connector to keep the connectors together until movement of the female connector is halted by the stop blocks. Continued pulling force causes the ramp projections to lift the cross-piece  74  and enable release of the male connector as the pawls  32  of the holder lock arms  26  drop back down or in against the latch edges. 
     The male and female connectors move as a unit rather than moving against or relative to each other. Full mating of the connectors is ensured. The unit can still move slightly after the shorting contacts have been disconnected to account for tolerances. The shorting contacts are reliably in electrical engagement with the female terminals until after full electrical and mechanical contact between the male and female terminals and before the terminals are disconnected. The holder covers and protects the mated connectors. Since the connectors don&#39;t move relative to reach other, wear on the terminals is reduced and fretting corrosion is minimized. The shorting spring prongs are wiped during the mating/unmating operation by the beveled cam surfaces and upper wall of the female connector. This wiping action removes oxide buildup and ensures reliable electrical contact every time the shorting contacts engage the female terminals. Because the connection and disconnection process involves only axial forces on the connectors to move them into and out of the holder, the assembly can be easily automated. 
     Since minor changes and modifications varied to fit particular operating requirements and environments will be understood by those skilled in the art, this invention is not considered limited to the specific examples chosen for purposes of illustration. The invention is meant to include all changes and modifications which do not constitute a departure from the true spirit and scope of this invention as claimed in the following claims and as represented by reasonable equivalents to the claimed elements.