Patent Publication Number: US-6217347-B1

Title: Electrical connector having multiple arrays of contacts with co-linear mounting points

Description:
BACKGROUND OF THE INVENTION 
     Personal computers are typically used in conjunction with peripheral devices such as disk-drive units that store and retrieve digital data from some type of storage medium. Peripheral devices supplement the computing operations carried out by the computer&#39;s microprocessor. Peripheral devices may be disposed external to the computer. Alternatively, peripheral devices may be adapted for installation within the computer. Internally-disposed peripheral devices that can be installed by the computer user are commonly available. 
     Internally-disposed peripheral devices are typically housed in bays within the computer. Access to these bays is typically achieved by way of an opening disposed along the computer&#39;s outer casing. The peripheral device is inserted through the access opening, thereby avoiding the need to remove the outer casing in order to install the device. The bay and the peripheral device are usually equipped with a series of rails and grooves. The rails and grooves guide the device into its installed position as it is inserted into the bay. Connectors are disposed on the peripheral device, and on one or more of the surfaces that form the sides of the bay. These connectors electrically couple the peripheral device and the computer. The connectors are typically arranged in a so-called “blind-mate” configuration, i.e., a configuration that allows a plug (male connector) and a receptacle (female connector) to mate with no action of the part of the user other than urging the two portions together in a particular alignment. 
     Compact external dimensions are considered a highly desirable characteristic of a personal computer. Hence, strict spatial constraints are imposed on the components utilized within such computers. These spatial constraints also apply to peripheral devices intended for use within personal computers. 
     Connector manufacturers have responded to the noted spatial constraints by reducing the physical dimensions of connectors employed in personal computers and peripheral devices. One means of reducing connector size is straddle mounting. The spring contacts of a straddle-mounted connecter are disposed along two facing rows wherein each contact is positioned to contact a printed circuit board positioned between the rows. This arrangement effectively doubles the number of contacts that can be accommodated within a given area on the mounting surface. The protrusion of contacts below the circuit board, however, makes straddle mounting impractical in certain densely-packaged electronic devices. 
     An alternative to straddle mounting consists of mounting both rows of contacts on the same side of the circuit board, with one row disposed directly above and extending beyond the other. This arrangement typically necessitates two adjacent rows of mounting points on the circuit board. Multiple rows of mounting points increase the footprint of the connector, i.e., the area on the circuit board needed to accommodate the connector. Such footprint increases consume space within the electronic device in which the connector is utilized. 
     It is therefore desirable to provide an improved blind-mate connector. The connector should accommodate multiple rows of electrical contacts in a manner that minimizes the dimensions of the connector both on and above the corresponding mounting surface. The present invention achieves these and other goals. 
     SUMMARY OF THE INVENTION 
     The present invention provides an electrical connector that is adapted for use on a substantially planar surface. The connector comprises a first and a second array of electrical contacts. Each array is coupled to the substantially planar surface. The second array of contacts is disposed above the first array in relation to the planar surface. Each contact in the first array is mounted directly to the planar surface, with the mounting points arranged in a substantially straight line. The second array is coupled to the planar surface by way of one or more tabs affixed to the surface. Each tab comprises a vertically-oriented member and a horizontally-oriented base. The vertically-oriented member elevates the second array in relation to the planar surface and the first array. The base of each tab is fixed to the planar surface along the same substantially straight line on which the first array of contacts is mounted. Furthermore, each tab is laterally offset from the second array of connectors, thereby allowing the second array to be positioned directly above the first array. The two arrays of contacts are thus disposed on the planar surface in a manner that minimizes the amount of space occupied by the connector both on and above the surface. A preferred embodiment of the connector further comprises a housing that is fixed to the planar surface. The housing has a plurality of apertures and troughs that engage the contacts. The contact arrays and the housing form a plug, i.e., a male connector. 
     The invention also provides a system for electrically coupling a first and a second electronic device. The system comprises a plug-type connector as described above, and a receptacle-type connector. The plug and the receptacle are fixed to the first and the second electronic devices, respectively. The receptacle comprises a plurality of contact elements that are adapted to engage the contact arrays of the plug. The engagement of the contact elements and the contact arrays electrically couples the first and the second electronic devices. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of a preferred embodiment, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show an embodiment that is presently preferred. The invention is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings: 
     FIG. 1 is an exploded view of an electrical connector in accordance with the present invention; 
     FIG. 2 is a perspective view showing a lower array of electrical contacts of the connector of FIG. 1; 
     FIG. 3 is a side view showing an upper and a lower array of contacts of the connector of FIG. 1; 
     FIG. 4 is a partially exploded view of the connector of FIG. 1; 
     FIG. 5 is a perspective view of the connector of FIG. 1 in a fully assembled state; 
     FIG. 6 is a cross-sectional view of the connector of FIG. 1 and a receptacle that engages the connector; 
     FIG. 7 is a front view of a computer and a peripheral device in which the connector of FIG. 1 can be utilized; and 
     FIG. 8 is a partially exploded view of a prior-art electrical connector comprising contacts that are fixed to a mounting surface along two rows. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides an electrical connector that is adapted for use on a substantially planar surface. A preferred embodiment of the invention is described in conjunction with a personal computer and a peripheral device for use in the computer. This particular configuration is presented for exemplary purposes only. Accordingly, the invention should not be limited to the particular configuration shown, as the invention can be applied to other types of electronic devices. 
     A presently-preferred embodiment of the invention is illustrated in FIGS. 1 through 6. The invention provides an electrical connector  10 . The exemplary connector  10  is a plug (male connector) that is adapted to engage a receptacle (female connector). As an example, the connector  10  may be used in conjunction with a peripheral device  11  for a personal computer  12 , as shown in FIG.  7 . The peripheral device  10  may be any of a number of commonly-available accessories for personal computes  12 , such as a removable disk-drive unit. The peripheral device  10  is adapted for installation in a bay  13  within the computer  12 . The bay  13  is accessible from the exterior of the computer  12 , thereby allowing the user to install the peripheral device  11  without removing the outer casing of the computer  12 . The connector  10  is utilized to electrically couple the peripheral device  11  and the computer  12 . 
     The connector  10  comprises a first electrical-contact array  14 . The array  14  comprises one or more electrical contacts  15 . The contacts  15  are disposed on a substantially planar surface, as is best shown in FIG.  2 . In the exemplary embodiment, the planar surface is a printed circuit (PC) board  16 , and the contacts  15  are fixed to the board  16  by soldering. Other types of mounting surfaces and other attachment means are also within the contemplated scope of the invention. The PC board  16  is disposed along the exterior of the exemplary peripheral device  11 . 
     The contacts  15  are disposed in a substantially parallel orientation. The center-to-center distance between adjacent contacts  15  is preferably about 0.050 inches. The exemplary embodiment comprises a total of twenty-two contacts  15 . Each contact  15  comprises a solder tail  15   a . Each solder tail  15   a  is fixed to the PC board  16  at a mounting point  17 . The mounting points  17  are disposed in a substantially co-linear arrangement on the board  16 . Hence, the mounting points  17  define a substantially straight line  18  along the surface of the board  16 . Each contact  15  further comprises an elevated section  15   b.  Each elevated section  15   b  is fixed to the raised end of a solder tail  15   a . The elevated sections  15   b  are thus disposed at a fixed height above the board  16 , and share a substantially co-planar relationship. 
     The invention further comprises a second electrical-contact array  19 . The array  19  comprises one or more contacts  20 . The contacts  20  are arranged in a substantially parallel orientation, as is best illustrated in FIG.  4 . The center-to-center distance between adjacent contacts  20  is preferably about 0.050 inches. The exemplary embodiment comprises a total of twenty-two contacts  20 . 
     The contacts  20  are disposed at a fixed height directly above the elevated sections  15   a  of the contacts  15 , i.e., the contacts  20  and the elevated sections  15   a  are vertically disposed above a common position on the PC board  16 . (The term “above,” as used in this context, signifies that the contacts  20  are located at a farther distance from the mounting surface, i.e., the board  16 , than the elevated sections  15   a . The contacts  20  may actually be positioned below the elevated sections  15   a  in applications in which the connector  10  is disposed on the underside of the board  16 .) The contacts  15  and  20  thus define two substantially parallel rows of contacts. Furthermore, both rows are positioned above a common location on the PC board  16 . This arrangement is best shown in FIGS. 1,  3 , and  4 . In addition, the contacts  20  are disposed in a substantially parallel orientation with respect to the contacts  15 . 
     The contacts  20  are fixed to a transverse member  21 . The transverse member  21  is made of an electrically-conducting material. The longitudinal axis of the transverse member  21  is disposed at an angle of about 90 degrees in relation to the longitudinal axis of each contact  20 . Four transverse members  21  are utilized in the exemplary embodiment. The contacts  20  are grouped on the transverse members  21  in a manner that is most clearly shown in FIGS. 1 and 4. The grouping of multiple contacts  20  on a common member  21  (as illustrated in the figures) causes each member  21  to function as a bus, i.e., the members  21  conduct electrical signals between multiple sources and destinations. The bussing arrangement for a particular connector is tailored to the protocol of the electronic device with which the connector is to be utilized. For example, the disclosed embodiment is intended for use with devices that can be electrically coupled via two major connector groupings, e.g., a power grouping  22  and a signal grouping  23 , with two sub-groupings within each major grouping. 
     A tab  24  is disposed at an end of each transverse member  21 . The tab  24  is made of an electrically conducting material. The tab  24  comprises a vertically-oriented member  24   a  and a horizontally-oriented base  24   b . The base  24   b  is affixed to the PC board  16 . Preferably, the base  24   b  is soldered to the board  16 . The vertically-oriented member  24   a  elevates the transverse member  21  and the second contact array  20  in relation to the board  16  and the contact array  14 . Furthermore, each tab  24  is laterally offset from the array  19 , i.e., the tab  24  and the contacts  20  are disposed in different positions along the “y” axis denoted in the figures. Each tab  24  is also offset longitudinally from the array  19 , i.e., the tab  24  and the contacts  20  occupy different positions along the “x” axis. The significance of these features is explained below. 
     Each base  24   b  is fixed to the PC board  16  at a mounting point  25 . Each mounting point  25  is disposed along a projection of the line  18 , i.e., the mounting points  25  and  17  are disposed in a substantially co-linear arrangement. Hence, the locations at which the contact arrays  14  and  19  are coupled to the board  16  are aligned in a single row. 
     The array  19  is suspended above the PC board  16  as a result of the geometric relationship between the contacts  20 , the transverse member  21 , and the tab  24 . The lateral offset between the tab  24  and the contacts  20  allows all of the space directly below the contacts  20  to be utilized in accommodating the contacts  15 . The co-linear arrangement of the mounting points  17  and  25  is facilitated by the grouping of the contacts  20  into a relatively small number of mounting tabs  24 . This arrangement allows the mounting points  17  and  25  to be disposed along a single row with little or no increase in the length (x dimension) of the connector  10  relative to a comparable “dual-row” connector. Hence, the invention eliminates one of the primary disadvantages associated with arranging multiple arrays of contacts in a vertical grouping, i.e., the need for multiple rows of mounting points. 
     The exemplary connector  10  further comprises a housing  26 . The housing  26  is formed from a rigid or semi-rigid, electrically-insulating material. The housing  26  comprises a longitudinal member  27  having a first tongue  30  and a second tongue  31 . The housing  26  further comprises a first lateral member  32  and a second lateral member  33 . The lateral members  32  and  33  are disposed at opposing ends of the longitudinal member  27 . 
     The longitudinal member  27  includes a plurality of laterally-oriented apertures  27   a . The tongues  30  and  31  each define a plurality of troughs  30   a  and  31   a . The troughs  30   a  are disposed along an upper surface  30   b  and a lower surface  30   c  the tongue  30 . The troughs  31   a  are likewise disposed along an upper surface  31   b  and a lower surface  31   c  of the tongue  31 . Each trough  30   a  and  31   a  is substantially aligned with one of the apertures  27   a.    
     The apertures  27   a  and the troughs  30   a  and  31   a  are adapted to engage the contacts  15  and  20 . The contacts  15  and  20  are disposed within the apertures  27   a  and the troughs  30   a  and  31   a  when the connector  10  is fully assembled (FIG.  5 ). A portion of each contact  20  is exposed along the upper surfaces  30   b  and  31   b  of the tongues  30  and  31 . A portion of each contact  15  is likewise exposed along the lower surfaces  30   c  and  31   c . The housing  26  is fixed to an edge of the PC board  16 , thereby securing the connector  10  to the PC board  16  (variants of the connector  10  within the contemplated scope of the invention may position the connector  10  at locations other than the edge of the PC board  16 ). 
     For exemplary purposes, the connector  10  is described in conjunction with a peripheral device  11  for use in a personal computer  12 . The peripheral device  11  (including the connector  10 ) is guided into the bay  13  of the computer  12  by the engagement of grooves and rails (not shown) disposed along the sides of the bay  13  and the device  11 . As the device  11  approaches its “installed” position within the bay  13 , the connector  10  slidably engages a receptacle  34  fixed within the bay  13 . More particularly, the receptacle  34  includes a plurality of contact elements  34   a  that engage the exposed surfaces of the contacts  15  and  20 , as shown in FIG.  6 . The engagement of the contact elements  34   a  and the contacts  15  and  20  electrically couples the peripheral device  11  and the computer  12 . 
     The present invention thus furnishes a means for disposing electrical contacts on a planar surface in a manner that minimizes the amount of space occupied by the contacts both on and above the surface. The reductions in connector size provided by the invention are significant in light of the strict spatial constraints imposed on personal computers and many other electronic devices. Furthermore, this minimization is achieved without reducing the physical separation between individual contacts. For example, the exemplary embodiment possesses a maximum width (y dimension) of about 11.45 mm. FIG. 8 illustrates a comparable prior art connector  35  in which an upper row of contacts  36  are connected to a circuit board  37  via a second row of individual solder tails  36   a . The connector  35  has a maximum width of about 12.95 mm. The greater width of the connector  35  is a result of the need to maintain physical separation between the solder tails  36   a  and solder tails  38   a  of a lower array of contacts  38 . 
     The invention also eases the installation and removal of electronic devices. More specifically, the invention provides a connector  10  that allows electronic devices to be electrically coupled and decoupled without the need to rewire any electrical connections. Additionally, the design of the connector  10  simplifies the manufacturing and installation processes in relation to connectors such as the connector  28 . In particular, the upper-level contact array  19  can be formed from a single stamping, thereby reducing the number of manufacturing steps. Furthermore, grouping multiple contacts  20  onto a single mounting point  25  reduces the number of soldering operations required to assemble the connector. Grouping the contacts  20  in the noted manner can also provide advantages from an electrical standpoint. For example, the signal grouping  23  in the described embodiment actually enhances the quality of the signal transmission at high switching speeds. 
     It is to be understood 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 the 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. For example, one particular variation of the connector  10  that falls within the scope of the invention forgoes the use of a lower array of contacts, i.e., the array  14 . This embodiment can be used to suspend an array of contacts, e.g., the array  19 , above an electronic component other than another grouping of contacts. Such an embodiment can be utilized to achieve a space savings similar to that described in connection with the disclosed embodiment. Another possible variation of the connector  10  may forgo the use of the housing  26 . In this particular variant, the contacts  15  and  20  are coupled directly to a receptacle, i.e., a female connector, that is adapted to receive the contacts  15  and  20 .