Patent Publication Number: US-6340315-B1

Title: Battery connector assembly with improved contacts arrangement

Description:
FIELD OF THE INVENTION 
     The present invention relates to a battery connector assembly, and particularly to a battery connector assembly for use with a Personal Digital Assistant (PDA) wherein the battery connector has an improved contacts arrangement. 
     BACKGROUND OF THE INVENTION 
     A PDA is a portable device for carrying data and information which can be connected to computers. It is always provided with a battery connector assembly for transmitting electric power between the PDA device and a printed circuit board (PCB). Taiwan patent application Nos. 84210634 and 83107591 disclose similar battery connector assemblies. Referring to FIG. 8, a prior art battery connector assembly comprises a receptacle connector  100  and a plug connector  200  mateable with each other. The receptacle connector  100  comprises an insulative housing  105  and a plurality of conductors  104  engageably received in the housing  105 . The housing  105  defines a row of receiving slots  101  opened in top and side walls thereof and forms a row of partitions  102  separating the receiving slots  101  from each other. Each partition  102  defines a recessed opening  103  in one side thereof for receiving a corresponding conductor  104 . The plug connector  200  is constructed to correspond with the receptacle connector  100  and comprises an insulative housing  201  and a plurality of conductive plates  202  assembled in the housing  201 . In use, the plug connector  200  is mated with the receptacle connector  100  whereby the conductive plates  202  of the plug connector  200  electrically connect with the conductors  104  of the receptacle connector  100  to transmit electrical power and signals between the PCB and the PDA device. 
     However, developments in computers have resulted in faster and faster signal transmission demands. Electrical circuits in PDA devices are becoming more and more complex. Increasingly, the prior art battery connector assembly, with only a single row of conductors electrically connecting with a single row of conductive plates thereof, cannot adequately handle these faster signal transmission demands. 
     Hence, an improved battery connector which can provide more conductive contacts to transmit electrical power within a compact space is required to overcome the disadvantages of the prior art. 
     BRIEF SUMMARY OF THE INVENTION 
     A main object of the present invention is to provide a battery connector assembly having more contacts than the prior art yet within a compact space. 
     Another object of the present invention is to provide such an assembly whereby all electrical connections are foolproof, safe and effective. 
     To fulfil the above-mentioned objects, a battery connector assembly comprises a plug connector and a receptacle connector mating with each other. The plug and receptacle connectors are similar in structure. Each comprises an insulative housing and two sets of conductive contacts engaged in the housing. Each housing comprises a first side having a step-shaped surface which forms a lower step and an upper step. Each step forms a row of partitions and defines a row of slots separated from each other by the partitions. The row of slots in the lower step is horizontally offset from the row of slots in the upper step by a distance equal to half the pitch between adjacent contacts. The slots in each step receive a complementary set of contacts. When the connectors are mated, the sets of conductive contacts in the lower and upper steps of the plug connector are mated with complementary sets of contacts in the upper and lower steps of the receptacle connector, respectively. Thus, compared with the prior art, roughly twice the number of conductive contacts are available in a given connector length for transmitting electrical power and signals. Furthermore, effective and safe electrical connection is achieved due to the horizontal and vertical offset between contacts. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a plug connector and a receptacle connector of the present invention; 
     FIG. 2 is similar to FIG. 1 but taken from a bottom aspect; 
     FIG. 3 is a top planar view of FIG. 2; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIG. 1; 
     FIG. 5 is a cross-sectional view taken along line  5 — 5  of FIG. 1; 
     FIG. 6 is an assembled view of FIG. 4; 
     FIG. 7 is an assembled view of FIG. 5; and 
     FIG. 8 is an exploded, partially cut-away perspective view of a prior art battery connector assembly. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, a battery connector assembly  1  in accordance with the present invention comprises a plug connector  2  and a receptacle connector  3  electrically mating with each other for transmitting electrical power and signals between a PCB and a PDA device (both not shown). 
     The plug connector  2  comprises an insulative plug housing  20  in a rectangular shape, and sets of first plug contacts  4  and second plug contacts  5  engageably received in the plug housing  20 . 
     The housing  20  has a first side  22  and a second side  21  opposite to the first side  22 . An elongate recess  23  is defined in the second side  21  and defines a row of openings  232  in a peripheral wall (not labeled) defining one side thereof. A pair of positioning posts  29  project from opposite ends of the second side  21  for engaging with the PCB. As is best seen in FIG. 2, the first side  22  of the housing  20  has a stepped shape and forms an upper plug step  25  and a lower plug step  28 . The upper plug step  25  forms a row of elongate upper plug partitions  220  spaced apart from each other, and defines a row of upper plug slots  221  therebetween for receiving the set of second plug contacts  5 . The lower plug step  28  forms a row of lower plug partitions  280  spaced apart from each other and defines a row of lower plug slots  281  therebetween for receiving the set of first plug contacts  4 . Each lower plug slot  281  communicates with a corresponding opening  232  of the recess  23 . The row of lower plug slots  281  is offset from the row of upper slots  221  by a half pitch of two adjacent first conductive plug contacts  4  in an elongate direction of the housing  20 . Accordingly, the set of first plug contacts  4  is offset from the set of second plug contacts  5  by the half pitch in an elongate direction of the housing  20 . Additionally, two elongated indents  24  are defined in opposite ends of the first side  22 . A guiding rib  241  protrudes into each indent  24  from an inward wall defining said indent  24 . The guiding rib  241  forms a slanted tip surface  240  at a forward end thereof for guiding the receptacle connector  3  when mating it with the plug connector  2 . 
     Each first plug contact  4  comprises a plug contact portion  42  which horizontally extends through a lower plug slot  281 . A plug retaining portion  44  extends from the plug contact portion  42  through a corresponding opening  232  communicating with the lower plug slot  281 , and abuts against a lower surface  234  of the recess  23 . A solder portion  46  further extends from and perpendicular to the plug retaining portion  44  toward the second side  21 , forming a horizontal solder tag  462  at its outer end. Each second plug contact  5  comprises a plug contact portion  52  extending through a corresponding upper plug slot  221 , and a solder portion  54  extending perpendicularly from the plug contact portion  52  and toward the second side  21  to form into a horizontal solder tag  542 . The plug contact portion  42  of each first plug contact  4  is located lower than the plug contact portion  52  of each second plug contact  5  with respect to the second side  21 . The horizontal solder tags  462 ,  542  of the first and second plug contacts  4 ,  5  are coplanar with the second side  21  for soldering to the PCB using surface mounted technology (SMT). 
     The receptacle connector  3  comprises an insulative receptacle housing  30  in a rectangular shape and sets of first receptacle contacts  7  and second receptacle contacts  8  engagably received in the housing  30 . 
     The housing  30  comprises a first side  81  and a second side  82  opposite to the first side  81 . The first side  81  has a stepped shape and forms a lower receptacle step  86  and an upper receptacle step  88  which extend along opposite elongate sides of the first side  81 . The lower and the upper receptacle steps  86 ,  88  respectively forms a row of lower and a row of upper receptacle partitions  810 ,  880  spaced apart from each other, and respectively define a row of lower and a row of upper receptacle slots  811 ,  881  therebetween for receiving the sets of first and second receptacle contacts  7 ,  8 , respectively. Consistent with the structure of the plug connector  2 , the row of lower receptacle slots  811  is offset from the row of upper receptacle slots  881  by a half a pitch of two adjacent first receptacle contacts  7  in an elongate direction of the housing  30 . Accordingly, the set of first receptacle contacts  7  is offset from the set of second receptacle contacts  8  by the half pitch in the elongate direction of the housing  30 . Note that the distance between adjacent upper plug slots  221 , adjacent lower plug slots  281 , adjacent lower receptacle slots  811 , and adjacent upper receptacle slots  881  are all equal. The pitch between the contacts  4 ,  5 ,  7  and  8  are thus also equal, and the amount of offset between sets of contacts  4  and  5 , and  7  and  8 , is also equal. Each lower and each upper receptacle slot  811 ,  881  defines a notch  730 ,  830  (FIG. 5) at a lower end thereof. In addition, two latching members  300  project from opposite ends of the first side  81  for engaging with the two indents  24  of the housing  20  of the plug connector  2 . 
     Referring to FIGS.  1  and  3 - 5 , the first and second receptacle contacts  7 ,  8  are similar in structure and are now described below. Each first/second receptacle contact  7 / 8  comprises a resilient portion  71 / 81 , a receptacle contact portion  70 / 80  generally extending upward from one end of the resilient portion  71 / 81 , and a receptacle retaining portion  73 / 83  generally extending downward from the other end of the resilient portion  71 / 81  and interferingly retained in the housing  30 . The receptacle contact portion  70 / 80  forms an apex  701 / 801  for contacting with a corresponding plug contact portion  52 / 42  of the second and first plug contact  5 / 4  of the plug connector  2 . The apex  701  of each first receptacle contact  7  extends lower than the apex  801  of each second receptacle contact  8  with respect to an outer surface  821  of the second side  82  of the receptacle connector  3 . 
     In assembly, referring to FIGS. 1 to  7 , the plug contact portions  42 ,  52  of the first and second plug contacts  4 ,  5  are engaged within the lower and upper slots  281 ,  221  of the housing  20 , respectively. The plug retaining portions  44  of the first plug contacts  4  extend through respective openings  232  and abut against a bottom surface  234  of the recess  23 . The plug connector  2  is mounted onto the PCB by the positioning posts  29  thereof being retained in two holes (not shown) defined in the PCB, and the solder tags  462 ,  542  of the first and second plug contacts  4 ,  5  are soldered to the PCB by SMT. The first and second receptacle contacts  7 ,  8  are engaged within the rows of lower and upper receptacle slots  811 ,  881  of the housing  30 , respectively, with the retaining portions  73 ,  83  thereof retained in the notches  730  and  830  (FIG.  5 ), respectively. The receptacle connector  3  is then attached to the PDA device. 
     In use, the plug connector  2  is mated with the receptacle connector  3  with the indents  24  of the plug connector  2  engaging with the latching members  300  of the receptacle connector  3 . Meanwhile, the first and second plug contacts  4 ,  5  of the plug connector  2  are mated with corresponding second and first receptacle contacts  8 ,  7  of the receptacle connector  3 , respectively. During mating, the row of lower plug partitions  280  of the plug connector  2  unavoidably slide over the set of corresponding first receptacle contacts  7  of the receptacle connector  3  because of their offset, but cannot damage them because they do not extend higher than the set of second plug contacts  5 . Furthermore, the first plug contacts  4  of the plug connector  2  cannot contact with the first receptacle contacts  7  of the receptacle connector  3  because the row of first receptacle contacts  7  are horizontally offset by a half pitch from the row of second receptacle contacts  8  and thus from the row of first plug contacts  4 , thereby ensuring a safe and effective electrical connection between corresponding plug contacts and receptacle contacts for transmitting electrical power and signals between the PCB and the PDA device. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.