Abstract:
An insertion-force reducing connector assembly and method for mating multi-terminal male and female connectors of the type used in automotive wiring harnesses. The female connector is movably retained in a frame-like holder by a self-actuating force reducing link that automatically couples a male connector inserted into the holder to the female connector with an insertion/withdrawal ratio in which the female connector moves away from the male connector in the terminal-mating direction more slowly than the male connector is inserted, thus allowing the connectors to be coupled over a longer than normal terminal-mating distance and reducing the insertion force needed to mate the terminals. The method includes the steps of coupling the female connector to the holder and subsequently mating the male connector to the female connector in the holder.

Description:
FIELD OF THE INVENTION 
     The present invention is in the field of multi-terminal male/female electrical connectors of the type commonly used for automotive wiring harness connections, and more specifically to mechanisms used with such connectors to reduce the amount of assembly force needed to fully mate their terminals. 
     BACKGROUND OF THE INVENTION 
     Multi-terminal electrical connectors can require a significant amount of “insertion” force to properly mate their respective sets of terminals. Certain applications require large numbers of mating terminals, for example in automotive wire harness connectors where dozens of pin-type terminals may be contained in a single connector set. The more terminals in the connector set, the more force needed to mate the connectors. The higher the insertion force, the more likely it is that terminals will be improperly mated or damaged. 
     One solution for reducing insertion force has been to provide a mechanical assist structure on one of the connectors, for example an exterior lever for engaging a portion of the other connector once the connectors are initially mated. The lever is manually operated to draw the connectors into a fully mated condition, the lever&#39;s mechanical advantage reducing the amount of assembly force needed to do so. The levers are sometimes provided with locking structure to lock the fully mated connectors and their terminals together in a manner preventing unintended separation. 
     Another solution for reducing insertion force in such connectors has been to provide an actuator member or frame that holds or mounts a first of the connectors while a mating connector is partially inserted in a first terminal-mating direction. After partial connection or insertion, angled cam slots on the actuator member cause or require at least one of the mating connectors to be moved laterally or obliquely in a second direction to draw the connectors into a fully mated condition with a mechanical advantage. 
     Cam-assist levers are relatively bulky, exposed, and fragile features that usually require additional structure on their supporting connectors to keep them in a pre-lock condition ready to receive mating connectors. Assist levers further require the person mating the connectors to perform two different operations: axial insertion and lever-assist. Frame-type actuator members can also be bulky, add a third piece to the connector set that may require assembly to one of the connectors at the connector mating location, and require a multi-directional insertion sequence that increases the possibility of error by the person mating the connectors. 
     SUMMARY OF THE INVENTION 
     The invention is an insertion force reducing structure built into a female connector holder to which the female connector is movably coupled, and activated by the insertion of the male connector to increase the straight-line terminal-mating distance between the connectors, thereby reducing the felt insertion force. The person mating the connectors simply plugs the connectors together in a straight line, while the holder automatically programs the relative axial movement of the connectors to achieve the reduction in insertion force. 
     In the preferred form, the holder is a frame sized to axially receive the mating portions of the female and male connectors from opposite sides for initial mating engagement within the frame, the connectors then continuing axial movement through the frame over the terminal-mating distance at different rates mechanically programmed by the frame, until fully mated. Self-actuating force-reducing links on the frame are coupled to the female connector to retain the female connector in the frame for axial back and forth movement in the terminal mating direction, and are positioned to automatically receive portions of the male connector when the male connector begins to mate with the female connector. The force-reducing links cause the male and female connectors to be coupled with an insertion/withdrawal ratio of X:Y, where X is the rate of insertion of the male connector and is greater than Y, and Y is the withdrawal rate of the female connector. The female connector accordingly moves backward in the terminal mating direction at a lesser rate than the male connector moves forward, effectively lengthening the terminal mating distance and reducing the insertion force distribution per unit length, thus reducing the actual insertion force needed to couple the connectors. 
     In a further preferred form, the holder frame fits closely around the female connector, and may even fully enclose it, so that the person assembling the connectors is effectively handling the female connector directly, and so that the overall bulk and operator-perceived complexity of the connector set is reduced. The force-reducing links are flush with or recessed from the outer surface of the holder frame, and can therefore be exposed in a manner allowing a simplified and robust assembly of the female connector to the holder frame via the links, as well as visual confirmation of their engagement with the male connector. 
     The holder frame includes alignment structure for guiding the male connector into engagement with the force-reducing links. In a preferred form the alignment structure cooperates with the female connector and the links such that the female connector must be in a forward, ready-to-mate position before the male connector can be inserted. 
     The invention also encompasses a method including the steps for assembling the female connector to the holder frame and the subsequent mating of the assembled female connector/holder assembly to the male connector with a mechanically programmed axial insertion/withdrawal ratio favoring the male connector. 
     These and other features and advantages of the invention will become apparent upon further reading of the specification in light of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a separated connector set according to the invention, looking toward the mating face of the female connector in its holder. 
     FIG. 2 is a front elevation view of the female connector/holder assembly of FIG.  1 . 
     FIG. 3 is a detailed perspective view of the upper surface of the female connector/holder assembly of FIG. 1, with a portion of the front edge of the holder cut away to better show detail of the force reducing link and the male connector alignment 
     FIG. 4 is an exploded top plan view of the separated male connector and the female connector/holder assembly of FIG. 1 aligned for mating. 
     FIG. 5 is a top plan view similar to FIG. 4, with the male connector beginning to mate with the female connector and engaging the force-reducing link on the female connector holder. 
     FIG. 6 is similar to FIG. 5, but with the male connector partway mated with the female connector. 
     FIG. 7 is similar to FIG. 6, but with the male connector fully mated with the female connector. 
     FIG. 8 is a side elevation view of the initial mating engagement of the connector set of FIG. 5, sectioned through the mating terminals of the connectors. 
     FIG. 9 is a side elevation view of the partway mated connector set of FIG. 6, sectioned through the connector terminals. 
     FIG. 10 is a side elevation view of the fully mated connector set of FIG. 7, sectioned through the connector terminals. 
     FIG. 11 is an exploded view of the connector set of FIG. 1, illustrating the manner in which the parts are first assembled and then mated. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a connector set using the insertion force reducing structure of the invention has a female connector assembly  10  and a male connector  16 . Female connector assembly  10  includes a connector holder  12  mounting a female connector  14  for limited back and forth movement in the connector mating direction. The male connector  16  is designed to be plugged axially into female connector  14  within the confines of holder  12 . Female connector  14  is shown at its forward limit of travel in holder  12 , at the end facing male connector  16 , and in the illustrated embodiment contained completely within the close-fitting holder  12  so that assembly  10  gives the appearance and feel of a single body to the person assembling the connector set. 
     Referring to FIGS. 1-4 and  8 , female connector  14  has an outer body  18 , in the illustrated embodiment with a rectangular shape, an inner terminal block  20  having a number of terminal cavities  22 ,  24  and corresponding terminals  23 ,  25  of known type, and a gap or space  19  separating the outer body or wall  18  from terminal block  20  to receive a forward shroud portion of male connector  16  over block  20  in known manner. The terms “female” and “male” as applied to connectors  14  and  16  refer to the mating relationship of their bodies and not necessarily to the types of terminal each contains. 
     Female connector  14  also has upper and lower connector posts or pins  26  for slidably connecting the female connector to female guide slots  54  in the upper and lower walls  44 ,  48  of holder  12 . Open-ended male alignment slots  28  are formed in the upper and lower walls  18   a  and  18   c  of the female connector&#39;s outer body  18 , opening at the forward or mating edge or face of the female connector to receive connector/guide pins on the male connector. The rear of female connector  14  contains openings (not shown) to receive a number of wires  29  (FIG. 8) into electrical connection with terminals  23 ,  25  in known manner. 
     Male connector  16  has a body  30 , also rectangular in the illustrated example, with a front shroud portion  32  sized to fit over female terminal block  20  in the space  19  between female terminal block  20  and female outer body  18 ; a male terminal block  34  containing a number of terminals  36 ,  37  of known type, corresponding to the terminals in the female connector; terminated wires  38  connected to terminals  36 ,  37  in known fashion; and, connector guide posts or pins  40  extending from the upper and lower walls of shroud portion  32  for alignment with male guide slots  56  on the female connector holder and with alignment slots  28  on the female connector when the connectors are mated. 
     In the illustrated example, female connector holder  12  is an open-ended rectangular frame whose walls  44 ,  46 ,  48 ,  50  generally follow the outer contours of female connector  14  for a close sliding fit between them. Upper and lower walls  44  and  48  each have an actuator recess  52  containing a force reducing link in a reasonably protected yet accessible and visible manner. Recess  52  is roughly triangular or wedge-shaped and extends only partway through the frame walls, with a bottom surfaces  52   a , front edge  52   b , rear edge  52   c , and arcuate radial edge  52   d . Male connector guide slot  56  opens into the front edge  52   b  from the front of holder  12 , while female connector guide slot  54  opens into rear edge  52   c  from the rear of holder  12 . Both the male and female guide slots extend through the bottom surface  52   a  of recess  52  to slidingly guide the connector pins from the male and female connectors, respectively. The front edge or face  58  of holder  12  is preferably beveled as shown at  58   a  to help guide the male connector  16  and its pins  40  into female connector  14  and slots  28  and  56 . Slots  28  and  56  and pins  40  in the illustrated example are offset from the centerline of connector/holder assembly  10  and connector  16  so that the male connector is properly oriented upon insertion. 
     Each recess  52  contains a self-actuating force-reducing link  60 , a pivoting lever arm sized and shaped to lie flat on recess bottom surface  52   a , rotatably secured at one end with a pivot pin  62  and movable in an arc from an initial engagement position against front edge  52   b  to a fully mated position against rear edge  52   c , following radius edge  52   d . Each link  60  has an inner female actuator slot  64 , an outer male actuator slot  66 , and an axial entry cutout  66   a  for allowing a male connector pin  40  into the male actuator slot  66 . Axial entry cutout  66   a  is aligned with the holder&#39;s male guide slot  56  and the female connector&#39;s alignment slot  28  when link  60  is against forward edge  52   b.    
     Referring next to the connector mating sequences illustrated in FIGS. 5-7 and  8 - 10 , once pins  40  on male connector  16  are aligned with slots  28 ,  56  and cutout  66   a , male connector  16  is pushed axially into initial mating engagement with female connector  14  in holder  12 . Male connector pins  40  enter through the aligned slots and cutouts into the inner ends of male actuator slots  66  of links  60 , as shown in FIGS. 5 and 8. As male connector  16  is moved further in the terminal-mating direction shown by the arrows in FIGS. 6 and 9, each link  60  is automatically actuated to begin rotating toward the rear of holder  12 , thereby actuating female connector  14  through pins  26  trapped in the inner actuator slots  64 . The inner actuator slots act as reduced radius cams to move the female connector rearwardly at a predetermined rate less than the forward insertion rate of male connector  16 . The relative displacement of the rear edges of male and female female connectors  16  and  14  is illustrated in FIGS. 6 and 7, with connector  14  clearly having moved a lesser distance than the male connector. 
     FIGS. 7 and 10 show the fully mated condition of the connectors. The motion of links  60  in recesses  52  is timed to coincide with full terminal mating, and the abutment of each link  60  against the rear edge  52   c  of recess  52  signals the end of the connector mating process. The overall distance moved by female connector  14  is some fraction of the distance moved by male connector  16 , lengthening the terminal-mating distance but ultimately allowing the male connector to overtake and fully mate with the female connector within the confines of holder  12 . This relative insertion/withdrawal ratio X:Y of the terminals in the connectors, where X is the insertion rate of the male connector terminals greater than Y, and Y is the withdrawal rate of the female connector terminals less than X, is best shown in FIGS. 8-10. The lengthening of the overall terminal-mating distance accordingly reduces the overall insertion force for the person assembling the connectors. 
     It will be understood by those skilled in the art that the insertion/withdrawal ratio, and the resulting insertion force reduction for a given set of connectors and terminals, can be programmed differently in a number of ways, for example by altering the length of links  60  and/or the length of their actuator slots; by altering the geometry of the links and/or actuator slots; and/or by altering the geometry of recesses  52 . It will also be understood that while rectangular connector and holder bodies with actuator links in the upper and lower walls is the preferred example, different numbers of actuators at different locations on differently shaped holders are possible (including a single such link on the holder). 
     Referring to FIG. 11, the connector set of FIGS. 1-10 is illustrated in a fully exploded view showing the method of assembling first the female connector  14  to holder  12  to form assembly  10 , and the subsequent mating of male connector  16  with assembly  10 . First, the female connector  14  is inserted axially into holder  12  from the rear side of the holder, with female connector pins  26  aligned with and sliding through female guide slots  54 . Next, actuator links  60  are installed vertically onto pivot pins  62  and female connector pins  26 , movably trapping the female connector  14  in holder  12  to form assembly  10 . With the female connector/holder  10  assembled, and the female connector and actuator links placed in the forward, ready-to-mate position shown in FIGS. 4 and 5, the male connector is inserted axially a first distance from the forward side into an initial engagement with the actuator links, and then a further distance axially while the male and female connectors are coupled by the actuator links to move in the pre-selected insertion/withdrawal ratio. Axial movement of the male and female connectors is then terminated by the actuator links on the holder at the predetermined point of full terminal mating. 
     It is possible to provide locking structure of known type, for example latches and tabs or locking fingers, on the bodies of the male connector and the female connector or holder to lock the connectors in the fully mated position. This will be a matter of choice for those skilled in the art, as many such structures are known. 
     It will be understood that the connector and holder bodies and the actuator links illustrated above will preferably be made from a suitable polymer or polymers in known manner, by way of example nylon or resin type plastics of the type commonly used for wire harness type connectors. 
     The foregoing illustrated example of the invention is for explanation rather limitation, as modifications such as those listed above and others will be apparent to those skilled in the art now that we have disclosed the invention via this preferred embodiment. The invention is intended to be limited only by the following claims. We accordingly claim: