Abstract:
An electrical connector assembly includes a female connector and a male connector, wherein the female connector comprises a first connector piece adapted to retain female terminals therein and a second connector piece having internal camming projections; the first and second connector pieces being disposed for relative movement such that, upon movement of the second connector piece towards the first connector piece by actuation of external camming members, the internal camming projects deflect spring contact members on the female terminals, whereby the force needed to mate or unmate male terminals with the female terminals is reduced.

Description:
This Appln claims benefit of Prov. No. 60/163,201 filed Nov. 3, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention is related to matable electrical connectors in which spring beam terminals in one of the connectors are deflected prior to mating engagement with terminals in the other connector to reduce the mating force and to enhance the durability of the terminals and of the plating on the terminals. 
     2. Brief Description of the Prior Art 
     Zero insertion force (ZIF) or low insertion force (LIF) electrical connectors or sockets typically employ some form of cam member to reduce or eliminate the insertion force as two electrical connectors are mated. These connectors are typically used to reduce or eliminate the frictional force between mating male and female terminals. This frictional or mating force can result in damage to the terminals and to the electroplating used to ensure an good electrically conductive interface. High mating forces can also reduce the number of mating and unmating cycles for which specific terminals can be employed. Terminals and connectors that have distinct advantages for certain applications cannot be used for potentially related applications in which the connectors must be mated or unmated more frequently because of damage to the mating interface. Conventional ZIF or LIF connectors have been used in applications of this type, but one problem is that prior art ZIF or LIF connectors require a separate camming member that must be actuated as an additional step in the mating and unmating process. These additional camming members and rotary or linear actuators also add an additional component requiring additional space and generally resulting in additional cost. 
     Many prior art ZIF or LIF electrical connectors are used in sockets for integrated circuit components. Others are used to connect wires to pins on printed circuit boards. U.S. Pat. No. 4,350,402 discloses one such board mounted zero insertion force electrical connector in which female terminals are located in an inner housing and an outer housing includes inclined actuating surfaces for spreading the contact beams when the outer housing is shifted relative to the terminals and to the inner housing. A linear cam is used to impart movement between the two housings resulting in separation of opposed contact arms. U.S. Pat. No. 4,067,633 also employs two shiftable housings and inclined contact actuating surfaces on the housing that moves toward the mating ends of the spring contacts. This latter connector employs external handles on the connector attached to wires. When these handles are pressed together the terminals are moved forward to spread the contacts so that pins on a printed circuit board can be inserted between the contact arms without significant frictional mating force. One problem with this approach is that the terminals can still be forced into engagement with the pins without first separating the female spring beam, thus resulting in damage to the contact interface. 
     Each of these prior art approaches requires and additional cam actuating step to mate the connectors. U.S. Pat. No. 4,655,526 discloses another low insertion force electrical connector in which spring beams are initially held in a partially open position and are then released when two connectors are mated. However, this approach requires a complicated contact structure including insertion of a coil spring between spring beams. This contact structure differs significantly from standard contacts that have proved reliable in may applicatons. 
     Another approach is to partially preload spring beam terminals so that the mating force is reduced. An example of one such approach is shown in U.S. Pat. No. 4,685,886. Although this approach has advantages it eliminates only part of the mating force and it is typically used to reduce mating force to insure complete connection and not necessarily to increase the number of mating cycles. 
     SUMMARY OF THE INVENTION 
     The instant invention overcomes many of these disadvantages by providing an electrical connector in which mating force is significantly reduced in a configuration in which the connectors are mated by simply inserting one connector into another without manipulation of a separate cam actuator. This invention permits standard female or receptacle terminals, that are typically intended to be used for a limited number of mating and unmating cycles to be employed in applications requiring many more mating cycles. One of the objects of this invention is to permit standard receptacle terminals that are commonly used in automotive applications as input and output terminals for attaching other components or appliances to the vehicle electrical system. For example, this approach will allow portable electronic devices to be repeatably connected and disconnected to an electronic bus in the vehicle. Another object achieved by invention is to provide this capability without significant cost disadvantages and without requiring numerous additional components while still being relatively easily molded. 
     The advantages of this invention are also not limited to motor vehicle applications. This invention can be employed in numerous applications including printed circuit board connectors, integrated circuit component sockets, and wire to wire connectors. 
     One especially significant advantage of this invention is that the two connectors cannot be mated or unmated without first deflecting spring beam terminals so that male terminals can be inserted or removed without damage to the contact interface and to the plating on the terminals. 
     This electrical connector assembly also incorporates by a cam actuation function and a connector latching function. Disengagement of the connector latch also separates the terminal mating interface so that the connectors can be unmated without damage to the terminals. 
     These and other advantages are achieved by an electrical connector assembly including first and second mating electrical connectors. The first electrical connector includes first and second housings and female terminals. The first housing includes cavities with the female terminals secured in the cavities and a deflectable camming lever. The second housing includes camming surfaces engageable with the female terminals to open the female terminals. The second electrical connector includes a mating housing and male terminals insertable into mating engagement with the female terminals. The mating housing includes a surface engagable with the camming lever during mating to deflect the camming lever and shift the second housing relative to the first housing and open the female terminals for insertion of the male terminals. 
     The first electrical connector has a molded housing with a molded latch engagable with the second electrical connector to latch the connectors in a mating position. The molded latch includes a camming surface for shifting a portion of the first electrical connector relative to the molded housing as the first and second electrical connectors are mated. 
     The first electrical connector of this assembly has a front mating face and a rear face. The terminals in this first connector have a deflectable spring contact section. A rear housing in this first connector includes cavities in which the terminals are secured. A front housing telescopes relative to the rear housing between a first forward and a second relative rearward position. The front housing has a front panel with a plurality of openings and camming projections on an interior surface of the front panel located adjacent the openings and facing rearward. A camming member is located adjacent to the front mating face of the connector. Deflection of the camming member brings the camming member into engagement with the front housing and moves the front housing toward the second relative rearward position and toward the contacts to bring the camming projections into engagement with the spring contact sections to deflect the spring contact sections. The second electrical connector includes a housing abutting the camming member when mated with the first electrical connector to deflect the camming member to cause deflection of the spring contact sections. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of a mated electrical connector assembly including first and second connectors. Wires or other conductors, which would extend from the electrical connectors, have been omitted for the sake of clarity. 
     FIG. 2 is a view of a receptacle electrical connector that would include female terminals. 
     FIG. 3 is a view of the rear housing, one of the subcomponents of the receptacle electrical connector shown in FIG.  2 . 
     FIG. 4 is a front view of the front housing, a second subcomponent of the receptacle electrical connector shown in FIG. 2, which is shiftable relative to the rear housing shown in FIG.  3 . 
     FIG. 5 is a rear view of the front housing, shown in FIG. 4, showing camming projections adjacent to openings in the front panel of the front housing. 
     FIG. 6 is a view of the plug connector housing, one of the subcomponents of the second electrical connector matable with the first electrical connector shown in FIG.  2 . 
     FIG. 7 is a sectional view showing two fully mated electrical connectors. One of the female spring beam receptacle terminals is shown. A camming projection used to spread spring beam contacts and reduce the mating force when pins are inserted into the female terminals as the two electrical connectors are mated is also shown. Pins in the plug connector have been omitted for the sake of clarity. 
     FIG. 8 is another sectional view of the mated connectors showing the camming member or camming latch as it engages the shiftable front housing which acts as a cam, as well as the release member on the plug connector housing. 
     FIG. 9 is an enlarged view of one of the cam openings in the front housing when viewed from the rear or interior of the front housing. 
     FIG. 10 is a rear view of one of the cam openings shown in FIG. 9 in which the side surfaces shown in the three dimensional representation of FIG. 10 are not seen so that the shape of the cam openings is more clearly revealed. 
     FIG. 11 is a view of a standard pin or male terminal that could be used in the plug connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The electrical connector assembly  2 , shown in FIG. 1, includes a first electrical connector  10  mated to a second electrical connector  60 . The first electrical connector  10  is a receptacle connector and includes a number of female contacts or terminals  50 , shown in FIG.  7 . The second electrical connector  60  is a plug connector that includes a plurality of pins  80  of conventional type, such as those shown in FIG. 11, or other conventional male terminals or leads. In order to reduce the mating force and to increase the durability of the mating terminals, and of the plating on these terminals, the first connector  10  includes a shiftable cam  40  in the form of a front housing member that deflects or spreads the spring beam contact section  52  on female terminals  50  as the pins are inserted between the spring beam contact sections  52 . When the second connector  60  is fully mated with the first electrical connector  10 , the spring beam contact sections  52  are released to engage the pins  80  to establish an electrical connection between mating terminals. The shiftable front housing cam  40  can also be moved into engagement with the spring beam contact sections  52  to disengage the spring beam contacts  50  from the pins  80  when the connectors  10  and  60  are to be unmated. This camming action permits many more mating and unmating cycles than would typically be possible for the contact in question and for the plating on the mating sections of these terminals. 
     The receptacle connector  10 , as shown in FIGS. 2 &amp; 7, includes a two part housing with female or receptacle terminals  50  mounted in the connector  10 . The rear housing  20 , shown in FIG. 3, includes terminal cavities  22  extending forward from the rear face or end  14  of the first electrical connector  10 . In the representative embodiment, there are two parallel rows of cavities  22 . Molded terminal latches  23  extend from the molded housing  10  into each of the terminal cavities  22  and secure the female terminals  50 , as shown in FIG.  7 . These deflectable molded latches  23  permit insertion of the terminals  50  through the rear end  14 , and engage the terminals  50  to prevent retraction of the terminals. These molded latches  23  are conventional and are used in many electrical connectors, especially those used in automotive applications. It should be understood, however, that other means could be employed to secure the terminals  50  in cavities  22 . For example, conventional deflectable tabs extending from the terminals themselves could be employed to engage shoulders in the terminal cavities. FIG. 7 however shows that the mating or contact section  52  extends beyond the rear housing  20  and beyond a front end of the terminal cavities  22  in housing  20 . The spring beam contacts forming the contact section  52  are exposed on the front of the housing  20 . As will be subsequently discussed, these spring beam contact  52  are positioned to enter openings in the front housing  40  so that the spring beam contacts  52  can be outwardly deflected for receiving mating pins or male terminals  80 . 
     The preferred embodiment of the rear housing  20  is molded as one piece. In addition to the terminal latches  23 , there are two exterior camming members  24  extending from opposite sides of the rear housing  20 . These camming members are also molded as a part of the one-piece housing  20 . Each camming member  24  is molded as a cantilever beam with the cantilever beam base  36  joined to the main body of the rear housing  20  adjacent the rear face  14  of the receptacle connector  10 . Each cantilever beam camming member  24  extends toward the front or mating housing end  12 . A camming protrusion  30  extends from the inner surface  26  adjacent the free or distal end of the cantilever camming member  24 . This camming protrusion  30  faces inward and is located beyond the forward most part of the body of the rear housing  20 . Camming protrusions  30  on the two camming members  24  extend from the top and bottom sides of the rear housing  20  as viewed in FIG.  3 . Each camming protrusion  30  has an inclined leading edge or face  32  and an inclined trailing edge or face  34  so that the camming protrusions  30  have a generally triangular cross section. These inclined faces  32  and  34  are sloped so that a surface engaging either face during mating and unmating or the two connectors  10 ,  60 , or during assembly of the two connector housings  20 ,  40 , will slide along the sloping surface and outwardly deflect the two camming members  24 . 
     Each of the camming members  24  also includes a latching protrusion  38  extending from the outer surface  28  adjacent to its distal, forward or free end. One latching protrusion  38  is located near the center of each of the camming members  24  and the width of the latching protrusions  38  is less than the width of the camming protrusions  30  on the same camming member  24 . The latching protrusions  38  have a curved forward end  41  and an abruptly sloping rear end  39 . The curved forward end  41  is configured to engage a surface on the mating connector  60  during mating to deflect the camming member  24  and the camming protrusion  30  inward. The shape rear edge  42  is intended to form a latching surface to hold the two connectors  10 ,  60  securely mated. Each camming member  24  thus serves both as a connector latching member and to cam the spring beam contact sections  52  in a manner that will be discussed in greater detail. Camming member  24  can therefore also be referred to as a camming lever  24 , a camming latch  24 , or a molded latch  24 . In the preferred embodiment the structure of the camming member  24  can also be termed a cantilever beam  24  or a camming arm  24 . 
     The front housing  40  is secured to the rear housing  20  by the camming latches  24 . Front housing  40  is shown in greater detail in FIGS. 4 and 5. The front housing, which is also a one piece molded member, is assembled to the rear housing  20  after the female terminals  50  have been inserted into appropriate terminal cavities  22  from the rear of the rear housing  20 . The front housing  40  has four sidewalls all joined along a forward edge to a front wall or panel  48 . Rear housing  20  is inserted into the front housing  40  through the open rear of housing  40  with the four sidewalls enveloping the front portion of the rear housing  20 . Since the camming arms  24  are spaced from adjacent walls of the rear housing  20 , the top and bottom sidewalls of the front housing can be inserted between the camming arms  24  and the top and bottom of the rear housing  20 . When the front housing  40  is fully assembled on the rear housing  20 , the trailing edge  34  of the adjacent camming protrusion  30  will engage a front edge  42  of the front housing  40  along the top and bottom of the front panel  48 . The camming protrusions  30  will thus hold the front housing  40  on the rear housing  20 . It is important to note, however, that telescoping movement of the front housing  40  relative to the rear housing  20  is still possible. The front housing  40  can move from its forward position shown in FIG. 2, rearward relative to the rear housing  20  and to the female terminals  50 , which are prevented from rearward movement relative to the rear housing  20  by the molded terminal latches  23 . 
     FIG. 5 shows the interior or rear side of the front housing  40 . The four sidewalls and the front wall or panel  48  form a cavity in which the front portion of the rear housing  20  is received. A series of camming openings  44  are formed in the front panel  48 . Each of these openings  44  is aligned with a terminal cavity  22  in the rear housing  20 , and each opening is configured so that the front of the mating terminal section  52  fits within an aligned opening  44 . An enlarged view of one of these terminal openings  44  is shown in FIG.  9 . Other aspects of the structure of a terminal opening  44  are shown in FIG.  7 . FIG. 10 is a rear view of one of these openings  44  in which the outer edges of an opening  44  are show. The interior surfaces which appear in FIG. 9 appear as lines in this view. 
     Each terminal opening  44  is larger at its rear than at its front. A small opening  43  extends completely through the front panel  48  so that a pin  80  in the mating connector  60  can pass through the front housing  40  to mate with a corresponding female terminal  50 . Sloping camming projections  46  surround the opening  43 . These camming projections slope rearwardly toward an apex located generally along the horizontal centerline of both the opening  44  and the smaller pin opening  43  in the manner best seen in FIG.  7 . Each camming projection  46  has a sloping top surface  45  and a sloping lower surface  47  as seen in FIG.  9 . Each camming projection  46  is configured to fit between the upper and lower spring beams of the receptacle terminal mating section  52  of one receptacle terminal  50 . Each opening  44  is dimensioned so that the front mating portion  52  will fit within the rear portion of the opening  44 . As the front housing  50  moves rearward the camming projections  46  will engage the spring beams of the terminal  50  forcing them apart so that a male terminal or pin  80  can be inserted between the spring beams either with no mating force generated by the engagement of the male and female terminals or with a reduced mating force. This reduction in mating force will not only prevent damage to the physical structure of the terminals, but will also prevent damage to the electroplating added to the terminals to improve the mating interface. Reduction in mating force will also permit the terminals to be mated and unmated for significantly more cycles than would be possible for an otherwise comparable full force mating configuration. Adequate space at the top and bottom of each opening  44  is provided to permit the spring beams to flex outward. As seen in FIG. 4, openings may be provided above and below the pin openings  43  so that the terminals can be probed from the front to check for continuity. These probe openings provide access to the terminal  50  when the connector  10  is mounted in a panel or bulkhead and would otherwise be inaccessible. 
     The front housing  40  can also be referred to as a cam or cam insert or cam actuator since movement of the front housing  40  toward the rear housing  20  cams the terminal mating sections  52  outward. Rearward movement of the front housing  40  relative to the rear housing  20  is imparted by inward deflection of the camming members  24  and the camming protrusions  30 . When the camming members  24  is inwardly deflected, the camming protrusions  30  engage the front edge  42  of front housing  40  causing it to move rearwardly from the front position shown in FIGS. 2 and 7. When the plug connector  60  is mated to the receptacle connector  10 , the camming protrusions  30  will result when the plug connector housing  62  engages the camming members  24 . The male or plug connector housing  62  is shown in FIG.  6 . Together with the male terminals or pins  80 , this housing  62  forms the plug or male connector  60 . Plug connector housing  62  is molded, normally from the same material as the two housings  20  and  40 , which are part of the receptacle connector  10 . A plug housing cavity  64  is formed on the mating side of the plug housing  62  by a shroud formed for four walls, two sidewalls  66  and top and bottom walls  68 . Male terminals or pins  80  extend into the cavity  64 , which is shaped so that the mating end  12  of connector  10  will fit within the cavity  64 . When the two connectors are mated the top and bottom walls  68  function as engaging surfaces which abut the outer latching protrusions  38  on the camming members  24  to cause the inner camming protrusions  30  to engage and shift the front housing  40  rearwardly toward the rear housing  20  and into engagement with the female spring beam terminals  50 . The front edge of each wall  68  has a beveled surface  70 , which initially engages the latching protrusion  38  so that the connectors can be smoothly mated. 
     The walls  68  engage the outer latching protrusions  38  only in the initial part of the mating movement of the two connectors relative to each other. Thus the camming lever  24  and protrusion  30  are held in their cammed position for only the first part of this insertion. Each housing wall  68  includes an opening  76  that is at least as large as the latching protrusion  38 . One of these openings  76  is partially shown in FIG. 6, and FIG. 8 shows both latching protrusions  38  received within a latching opening  76 . Latching edge  39  engages a latching edge  78  in the wall opening  76  of the plug connector  60 . The latching opening  76  on the top wall  68  is obscured in FIG. 6 by the top depressible release member or appendage  72 . Openings  76  are recessed from the leading edge of walls  68  and from the beveled surface  70  along this leading edge. After the camming levers  24  have been inwardly deflected or depressed by the walls or surfaces  68  on the male connector housing  62 , continued movement of the plug connector  60  to its fully mated configuration, shown in FIGS. 1,  7  and  8 , will release the camming lever  24  when the latching protrusions  38  are aligned with the openings  76 . When so aligned the camming levers  24  will pivot back to their normal or neutral position, releasing the front housing or cam actuator  40  to move away from the rear housing  20 . The spring beam contacts  52 , initially spread apart by the camming projections  46  are then free to deflect back into engagement with the pins  80  which have now been inserted between the two spring beams forming contact sections  52 . 
     In the preferred embodiment of this invention, the spring beams themselves provide the spring force necessary to cause the front housing  40  to its forward on extended position. In this extended position the camming projections  46  do not exert any significant force on the terminal spring beams and do not interfere with the mating engagement between female terminals  50  and male terminals  80 . In other embodiments of this invention, an auxiliary spring or springs can be added to push the front cam  40  back to its extended position, In still other embodiments sufficient spring force may be provided by relying on only a portion of the resilient contacts to return the front cam to its extended position. In this context, it should also be understood that in some applications only a portion of the terminals need be cammed open in the manner discussed herein. 
     The male connector  60  provides means for zero or reduced force unmating as well as for mating. The housing  62  includes a depressible or deflectable release member  72  on the exterior of the top and bottom walls  68 . These release members  72  are molded as part of the housing  62 . Each release member  72  includes a release probe  74  in the form of a finger extending inwardly from the inner surface of the depressible member  72 . These release probes or fingers  74  are located immediately above the openings  76  in the walls  68 . When the release members  72  are depressed, the release probes  74  engage the latching protrusions  38  and force or cam the camming levers  24  to their inner or activated position. The camming protrusions  30  again engage the front edge  42  of the front housing or cam actuator  40  resulting in deflection of the spring beam contact sections  52  away from pins  80 . The pins  80  can then be removed from the female contacts  50  without damage to either mating contact surface or terminal. 
     One significant advantage of this approach is that mating terminals that are normally suitable for a relatively small number of full force mating and unmating cycles can now be used for many additional cycles. Thus terminals that have performed effectively in applications where the terminals are disconnected only in unusual circumstances, such as servicing of other components or an assembly, can now be used where various components are typically connected or disconnected with relative frequency. For example, terminals that are used in conventional automotive applications can be used as input and output terminals for electronic components that can be connected and disconnected to the motor vehicle electrical system or to electronic busses in the motor vehicles. The proven advantages of these terminals in assembling automotive harnesses and assemblies can then be employed in this new manner. 
     This configuration also allows the terminals to be mated in a conventional manner without the necessity of rotating or shifting a separate cam lever. The cam housing  40  is shifted as the plug connector is mated to the receptacle connector in a conventional manner. Furthermore, it is now possible to mate the plug connector  60  to the receptacle connector  10  without deflecting the camming lever. The connectors can also be mated by movement of only one connector while the other connector remains stationary. For example, the receptacle connector can be mounted in a panel or bulkhead opening and secured by screws or by conventional panel mount flanges located on the rear of the rear housing  20 . The plug connector  40  can be mounted on the rear of a component to be assembled or on the end of a cable or cord. Alternatively, the male connector can be mounted in a stationary position and the female connector can be moved to mate with the stationary male connector. The two connectors can also be used to connect two wire harness, in which case both connectors would be free to move during mating. In other applications, one of the connectors can be mounted to a printed circuit board, with pcb pins extending up through the housing. This cam approach can also be used for sockets or connectors for mounting integrated circuit components or for ZIF pin grid array packages. For all of these applications a zero insertion force, low insertion force or reduced insertion force connection can be accomplished without the necessity of manipulating a separate cam actuator or lever. The spring biased contacts are deflected or spread apart simply as a result of inserting one connector into engagement with the other with movement being necessary only in one direction or along one mating axis.