Abstract:
Described are an apparatus and method for blind mating electrical connectors. A connector-alignment collar includes a frame with a multi-sided base portion. The sides of the base portion define an area within which to receive a connector closely. A guide cantilever extends substantially perpendicularly from the base portion at a first side of the frame, and an alignment cantilever extends substantially perpendicularly from the base portion at a second side of the frame opposite the first side. The connector-alignment collar is placed around a first electrical connector on a first circuit board. The alignment cantilever is inserted into an alignment hole in the second circuit board while a guide notch in an edge of the second circuit board is urged against the guide cantilever. After the alignment cantilever is inserted into the alignment hole in the second circuit board, the first electrical connector on the first circuit board mates with the second electrical connector on the second circuit board.

Description:
FIELD OF THE INVENTION 
   The invention relates generally to electronic equipment assemblies that use electrical connectors to interconnect electronic subassemblies. More particularly, the invention relates to an apparatus for facilitating blind mating of electrical connectors in an electronics equipment assembly (i.e., without the aid of visual guidance). 
   BACKGROUND 
   A common approach used in the development of electronic equipment assemblies incorporates a modular design, in which multiple modules, subassemblies, or printed circuit cards are interconnected. Such an approach may simplify initial designs by allowing for the incorporation of other commercially available modules. With replaceable modules or printed circuit cards, provisioning of spares can be accomplished for each module independently, as required. An interconnected modular approach also simplifies maintainability by reducing repair tasks to board removal and replacement. 
   A recent trend in electronic equipment assemblies is toward higher data rates (hundreds of MHZ or higher) and smaller connector footprints. Such high data rates impose limitations on the length and manner of some electrical interconnections. Preferably, the length of interconnections should be kept to a minimum distance to avoid unwanted effects to the electrical signals. To keep interconnection length short, some designs directly interconnect overlapping or stacked circuit cards using board-to-board connectors. 
   Board-to-board connectors are relatively inexpensive and readily available. Some connectors have a high number of contacts distributed in a rectangular array (e.g., MEG-ARRAY® connectors) that may couple to a circuit board using a ball-grid array. Advantageously, these connectors keep interconnect lengths to a minimum. However, because of the small size and high density of contacts, damage to the connector&#39;s contacts can occur unless care is exercised during the mating and un-mating of the connector. Compounding this risk, many applications employ these delicate, high-density connectors in a blind mate configuration in which the connectors sit between overlapping circuit boards. Without an unobstructed view to the connector surfaces, the connectors are vulnerable to damage during the mating process. This can be particularly true for field replacements, where board removal and replacement occur in less-than-ideal conditions. Thus, there remains a need for improving the reliability of blind mate interconnections without unnecessarily increasing cost or complexity. 
   SUMMARY 
   In one aspect, the invention features a connector-alignment apparatus including a frame having a multi-sided base portion. The sides of the base portion define an area within which to receive a connector closely. A guide cantilever extends substantially perpendicularly from the base portion at a first side of the frame, and an alignment cantilever extends substantially perpendicularly from the base portion at a second side of the frame opposite the first side. 
   In another aspect, the invention features an electronic equipment assembly comprising first and second boards. The first board has an underside with a first electrical connector attached thereto, a guide notch formed along an edge of the first circuit board adjacent to one end of the first electrical connector, and an alignment hole adjacent to an opposite end of the first electrical connector. The second board has a top surface with a second electrical connector attached thereto and a frame around the second electrical connector. The frame has a multi-sided base portion with a guide cantilever extending substantially perpendicularly from a first side of the base portion and an alignment cantilever extending substantially perpendicularly from a second side of the base portion opposite the first side of the base portion. The guide notch receives the guide cantilever and the alignment hole receives the alignment cantilever to guide the mating of the first and second electrical connectors. 
   In another aspect, the invention features a method for blind mating a first electrical connector on a surface of a first circuit board to a second electrical connector on a underside of a second circuit board. The method comprises placing a connector-alignment collar around the first electrical connector on the first circuit board. The connector-alignment collar has a frame with a multi-sided base portion, a guide cantilever extending substantially perpendicularly from the base portion at a first side of the frame, and an alignment cantilever extending substantially perpendicularly from the base portion at a second side of the frame opposite the first side. A guide notch in an edge of the second circuit board is urged against the guide cantilever. While urging the guide notch against the guide cantilever, the alignment cantilever is inserted into an alignment hole in the second circuit board. After the alignment cantilever is inserted into the alignment hole in the second circuit board, the second electrical connector on the underside of the second circuit board mates with the first electrical connector on the surface of the first circuit board. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and further advantages of this invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
       FIG. 1  is a top-perspective view of an embodiment of an electronic equipment assembly with a connector-alignment collar constructed in accordance with the invention. 
       FIG. 2  is a perspective view of the electronic equipment assembly of  FIG. 1  having a mezzanine board removed revealing the connector-alignment collar. 
       FIG. 3  is a perspective cut-away view detailing the mezzanine board modified in accordance with the invention and spatially separated from a host board of the electronic equipment assembly with the connector-alignment collar of  FIG. 2  on a surface thereof. 
       FIG. 4A ,  FIG. 4B , and  FIG. 4C  schematically represent an example of an alignment procedure for connecting an electrical connector on a underside of a mezzanine board, constructed in accordance with the invention, to a host board receptacle using the connector-alignment collar to guide the mating process. 
       FIG. 5  is a cross-sectional view of a portion of the electronic equipment assembly of  FIG. 1 , taken through a centerline of the connector-alignment collar. 
       FIG. 6  is a perspective view of the connector-alignment collar of  FIG. 1  in more detail. 
       FIG. 7  is a perspective view of an exemplary connector-alignment system for use with the connector-alignment collar of  FIG. 6 . 
       FIG. 8  is a perspective view of an alternative embodiment of a connector-alignment collar constructed in accordance with the invention. 
       FIG. 9  is a perspective view of an embodiment of a host board receptacle of the connector-alignment system of  FIG. 7 . 
       FIG. 10A  is a cross-sectional view of the connector-alignment collar of  FIG. 6  in alignment with the host board receptacle of  FIG. 9 . 
       FIG. 10B  is a cross-sectional view of the connector-alignment collar coupled to the host board receptacle. 
       FIG. 10C  is a view of the connector-alignment collar coupled to the connector-alignment system, with the guide and alignment cantilevers of the connector-alignment collar being pivoted for detaching the connector-alignment collar from the host board receptacle. 
   

   DETAILED DESCRIPTION 
   Electronic equipment assemblies constructed in accordance with the present invention include a connector-alignment collar for facilitating blind mating between electrical connectors.  FIG. 1  shows a top-perspective view of an embodiment of an electronic equipment assembly  100  in which aspects of the invention may be implemented. The electronic equipment assembly  100  includes a chassis  105 , electronic circuitry  120  (hereinafter, a host printed circuit board, or host board), and an expansion module  125  housed therein. In some embodiments, the chassis  105  may house other devices, including other circuit boards, modules, components, and cooling devices. The chassis  105  includes a front panel  110 , left and right side panels  115 , and a bottom panel (not visible). The electronic equipment assembly  100  may also include top and rear panels (not shown). 
   The expansion module  125 , sometimes referred to herein as a mezzanine board  125 , includes a printed circuit board and sits spatially separated from and parallel to the host board  120  in a stacked-board configuration. One or more fasteners  130  securely fasten the mezzanine board  125  to the host board  120 . In addition, the mezzanine board  125  is electrically coupled to the host board  120  through one or more connector-alignment systems, described in more detail below. To facilitate the board-to-board interconnection between the host board  120  and the mezzanine board  125 , the host board  120  includes a connector-alignment collar  150  ( FIG. 2 ) having a guide cantilever  140  and an alignment cantilever  142  (which project above the plane of the mezzanine board  125 ). The mezzanine board  125  has a guide notch  135  and an alignment hole  136  for engaging the guide cantilever  140  and alignment cantilever  142 , respectively, when the mezzanine board  125  is coupled to the host board  120 . The two cantilevers  140 ,  142 , the guide notch  135 , and the alignment hole  136  facilitate mating and unmating of the host and mezzanine boards  120 ,  125 , described more fully below. 
     FIG. 2  shows the electronic equipment assembly  100  with the mezzanine board  125  removed to reveal the host board  120  with the connector-alignment collar  150  on a surface thereof. The connector-alignment collar  150  frames a host board (electrical) connector  155 . The connector-alignment collar  150  includes a base frame  152  from which the guide cantilever  140  and the alignment cantilever  142  extend. The host board  120  includes standoffs  145  for supporting the mezzanine board  125  ( FIG. 1 ), in conjunction with the connector-alignment collar  150 , as described below. 
     FIG. 3  shows the mezzanine board  125  disconnected from the host board  120  and positioned above the host board  120  as may occur during installation and removal from the chassis  105 . Extending from an underside surface of the mezzanine board  125  is an electrical connector  160  for mating with the host board connector  155  on the host board  120 . 
   The location of the electrical connectors  155 ,  160 , between the host board  120  and the mezzanine board  125 , can make their mating difficult because of the limited or nonexistent visual access to the connectors  155 ,  160 . Although visual access of the connectors  155 ,  160  may be possible from the side (i.e., between the host board  120  and the mezzanine board  125 ), such access would be inhibited here by the chassis side panels  115  ( FIG. 1 ). A configuration in which the connectors  155 ,  160  mate while being obstructed from view can be referred to as a “blind mate.” The front panel  110  of the electronic equipment assembly  100  ( FIG. 1 ) can be removed to facilitate the joining of the host and mezzanine boards  120 ,  125  when blind mating their respective connectors  155 ,  160 . 
   The standoffs  145  of the host board  120  can be used as a rough alignment aid. That is, the mezzanine board  125  can be positioned above the host board  120  and mounting holes in the mezzanine board  125  aligned with their respective standoffs  145 . This provides a rough alignment, at best, and may not be possible when the mezzanine board  125  includes captive fasteners  130  adapted for engaging the standoffs  145 . This would result in the equivalent of a blind mate of the fasteners  130  to the standoffs  145  providing “rough alignment” for mating the connectors  155 ,  160 . 
   The mezzanine board  125  includes the guide notch  135  adjacent to one end of the mezzanine board connector  160  and along the rear edge  165  of the mezzanine board  125 . The size and location of the guide notch  135  are for engaging a side surface of the guide cantilever  140  of the connector-alignment collar  150 . The guide notch  135  facilitates initial positioning of the mezzanine board  125  above the host board  120  during installation. 
   The mezzanine board  125  also includes an alignment hole  136  disposed adjacent to and at the other end of the mezzanine board connector  160  (i.e., on opposite sides of the mezzanine board connector  160  from the guide notch  135 ). The size and location of the alignment hole  136  are for receiving the alignment cantilever  142  of the connector-alignment collar  150 . The alignment hole  136  facilitates a proper orientation and alignment of the mezzanine board  125 , and hence the mezzanine board connector  160 , with respect to the host board connector  155 . Completion of the mating, as described more fully below, can be accomplished by urging the mezzanine board  125  against the host board  120  once the guide notch  135  and alignment hole  136  have suitably engaged the guide cantilever  140  and alignment cantilever  142 , respectively. 
     FIG. 4A ,  FIG. 4B , and  FIG. 4C  schematically represent an example of an alignment procedure for connecting a mezzanine board connector  205  to a host board connector  210 . Referring to  FIG. 4A , a top view of the host board connector  210  is shown in a relative, fixed position. Adjacent to a distal end of the host board connector  210  is a guide cantilever  215  of a connector-alignment collar  250 . Disposed adjacent to an opposite, proximal end of the host board connector  210  is an alignment cantilever  216  of the connector-alignment collar  250 . A mezzanine board  200 , also viewed from the top, includes a guide notch  220  defined along a rear edge  221  of the mezzanine board  200 . The mezzanine board connector  205  (shown in phantom) is disposed on an underside of the mezzanine board  200  with one end adjacent to the guide notch  220 . The mezzanine board  200  also includes an alignment hole  222  (through the mezzanine board  200 ), such that the mezzanine board connector  205  is disposed between the guide notch  220  and the alignment hole  222 . 
   During an installation procedure, the mezzanine board  200  is initially positioned in a plane above the host board connector  210 , with its rear edge  221  proximal to the guide cantilever  215  (here, the left side, as shown). The mezzanine board  200  may be aligned in a plane parallel to the host board connector  210 , although this is not necessary at this juncture. The rear edge  221  is below a tip of the guide cantilever  215  (the tip pointing out of the page). The rear edge  221  of the mezzanine board  200  is then moved distally toward the guide cantilever  215 , bringing the guide notch  220  into engagement with a side surface of the guide cantilever  215 . 
     FIG. 4B  shows a top view of the rear edge  221  of the mezzanine board  200  engaging the side surface of the guide cantilever  215 . Without any effort to align the mezzanine board  200  beyond this initial engagement, the mezzanine board connector  205  has not yet been aligned above the host board connector  210 . Having a single point of engagement at the guide cantilever  215 , the mezzanine board  200  can be rotated about the guide cantilever  215 , as indicated by the arrow, until the alignment hole  222  is aligned above the alignment cantilever  216 . Once aligned, the mezzanine board  200  can be urged against the host board connector  210  to complete the interconnection. 
     FIG. 4C  shows a top view of the properly aligned mezzanine board  200  with the alignment cantilever  216  extending through the alignment hole  222  and the guide cantilever  215  seated within the guide notch  220 . The mezzanine board connector  205  is now aligned directly above the host board connector  210 , the connectors  205 ,  220  being mated by urging the mezzanine board  200  against the host board connector  210 . Connector alignment is ensured during this last step by the guide cantilever  215  and alignment cantilever  216 . 
   Some board-to-board connectors can be mated “straight” with the plug and receptacle mating along an approach perpendicular to the mating plane. Some manufacturers recommend a different procedure for mating and unmating large pin count, high-density (e.g., two-dimensional, 400 position) connectors. Namely, a rolling motion is recommended, because it requires less effort. With the rolling motion, the plug (e.g., the mezzanine board connector  205 ) is first aligned above the host board connector  210  and then angled slightly, such that one end of the plug  205  contacts the host board connector  210  before the other end. The other end of the plug  205  is then directed toward the host board connector in the rolling motion to complete the mating procedure. Detaching (i.e., unmating) occurs in a similar manner (in reverse order). 
     FIG. 5  shows a cross-sectional view of the electronic equipment assembly  100 , taken through a centerline of the connector-alignment collar  150 . As shown from a side perspective view is the spacing, or height h 1 , between the top surface of the host board  120  and the bottom surface of the mezzanine board  125 . The mezzanine board connector  160  is also shown in cross-section being mated with the host board connector  155 . Also shown in the side view are the respective heights of the guide cantilever  140 , h 2 , and the alignment cantilever  142 , h 3 . The height h 2  of the guide cantilever  140  is greater than the height h 3  of the alignment cantilever  142 , to allow the mezzanine board  125  to first abut a side surface of the guide cantilever  140 , without interfering with the alignment cantilever  142 . In other embodiments, the guide cantilever  140  and alignment cantilever  142  can have equal or approximately equal heights. During an installation technique, referred to as “toe in,” when mating the connectors  155 ,  160 , the rear edge  165  of the mezzanine board  125  is lowered first toward the host board  120 , while the front edge of the mezzanine board  125  remains slightly upraised relative the rear edge. (The front panel  110  ( FIG. 1 ) can be removed to provide space for the toe-in insertion of the mezzanine board  125 .) With this approach, the distal ends of the connectors are allowed to engage first, before the proximal end does. Such a “toe in” approach may also facilitate insertion of the mezzanine board  125  within the chassis  105  ( FIG. 1 ). 
     FIG. 6  shows an embodiment of the connector-alignment collar  150  including the base frame  152 , and the guide cantilever  140  and the alignment cantilever  142  extending perpendicularly from opposite ends of the base frame  152 . The base frame  152  includes a closed perimeter including two opposing sidewalls  330  joined at each end by the end walls  340 . The guide cantilever  140  and alignment cantilever  142  are joined at opposite end walls  340 . The sidewalls  330  and end walls  340  form the closed perimeter dimensioned to enclose the host board connector  155  ( FIG. 3 ). In some embodiments, the base frame  152  may include an open perimeter, such as a configuration having one sidewall  330  only and the end walls  340 . 
   The base frame  152  has a bottom surface  342  that sits on the host board  120  when the connector-alignment collar  150  couples to the host board connector  155 , as described below. The bottom surface  342  includes a base portion of the sidewalls  330  and end walls  340 . The walls  330 ,  340  extend perpendicularly from the host board  120  when the connector-alignment collar  150  sits thereon. The sidewalls  330  have a height h 1 ′measured from their base (e.g., from the surface of the host board  120 ). The top of the sidewalls  330  each form a crest  335 , substantially parallel to the bottom surface  342 . The end walls  340  have a height h 4 , measured from their base, that is shorter than the sidewalls  330 . Additionally, the shorter end walls  340 , including a shortened corner portion  345  joining the end walls  340  to the sidewalls  330 , facilitate locking the connector-alignment collar  150  in place with respect to the host board  120 . 
   The alignment cantilever  142  includes an elongated column  300  coupled at its base to one of the end walls  340 . The alignment cantilever  142  is substantially rigid, such that it does not bend during insertion of the mezzanine board  125 , to promote proper alignment of the mezzanine board connector  160  with the host board connector  155 . To reinforce the alignment cantilever  142 , a reinforcing rib  310  can be included along at least a base portion of the rigid column  300 . The height of the reinforcing rib  310  does not extend above the height of the sidewall  330 , to ensure that the rib  310  does not interfere with the entry of the alignment cantilever  142  into the alignment hole  136  ( FIG. 3 ). 
   The alignment cantilever  142  includes at its top a tapered extension  305 . The tapered extension  305  may include a cone, as shown, to promote a capture and gross alignment of the mezzanine board  125  ( FIG. 3 ). The rigid column  300  may also taper along its length towards the top to provide a loose alignment when first inserted into the alignment hole  136 , the alignment being refined as the alignment hole  136  moves down the length of the column  300 , with any clearance therebetween being diminished by the taper. 
   The guide cantilever  140  includes an elongated column  315  coupled at its base to the other end wall  340 . The guide cantilever  140  is substantially rigid, such that it does not bend during insertion of the mezzanine board  125 , to promote proper alignment of the mezzanine board connector  160  with the host board connector  155 . To reinforce the guide cantilever  140 , a reinforcing rib  325  can be included. Preferably, the reinforcing rib  325  is located along an outer edge of the elongated column  315 , facing away from the base frame  152 . Being placed along an outer edge, there is no height restriction, so the reinforcing rib  325  can extend the entire length of the elongated column  315 , as shown. The guide notch  135  ( FIG. 3 ) abuts only an inner edge of the elongated column  315 , so the reinforcing rib  325  does not interfere with guide notch  135 . 
   The guide cantilever  140  includes a crown  320  at its outer end. Since the guide notch  135  ( FIG. 3 ) approaches the guide cantilever  140  from the side, without having to fit necessarily over the crown  320 , there is no related restrictions to the size of the crown  320 . In some embodiments, the crown  320  includes an enlarged member, such as the T-shaped handle  321  shown. A larger crown can serve as a visual aid to assist in locating the guide cantilever  140  during installation of the mezzanine board  125 . Additionally, a larger crown  320  can facilitate removal of the connector-alignment collar  150  itself by providing the T-shaped handle  321 , discussed further below. 
     FIG. 7  shows a perspective view of an exemplary connector system  360  usable in combination with the connector-alignment collar  150  ( FIG. 6 ). The connector system  360  includes a mating connector pair consisting of the host board connector  155  and the mezzanine board connector  160 . In one embodiment, the host board connector  155  is a receptacle and the mezzanine board connector  160  is a plug. One exemplary connector system includes MEG-ARRAY® connectors, available in connector sizes spanning 80 to 528-contact positions with the capability to support board-to-board stack heights from 4 to 14 mm, in increments of 2 mm. FCI USA Inc part no. 84520-002 represents an exemplary 400-position mezzanine board connector  160  with a 6.0 mm stack height. Part no. 74390-001 represents an exemplary mating 400-position host board connector  155  having a stack height of 8.0 mm. These connectors are available from FCI USA, Inc., of Etters, Pa. 
   The exemplary MEG-ARRAY® connector system  360  includes a key to assure proper mating orientation. The host board connector  155  includes a base portion  156  surrounding its perimeter that includes a large slot  355   b  at one end and a small slot  355   a  (not visible) at the other end. The mating mezzanine board connector  160  includes a large key  350   b  at one end and a small key  350   a  at the other end. The locations and sizes of the keys  350   a ,  350   b  are for interlocking with the slots  355   a ,  355   b  when the mezzanine board connector  160  is in the proper orientation with respect to the host board connector  155 . 
   The height h 1  of the overall mated connector system  360 , when the mezzanine board connector  160  is properly mated with the host board connector  155 , is often a predefined or specified value, sometimes referred to as the “stack height.” For applications in which the connector system  360  is used between adjacent circuit boards, the specified stack height typically corresponds to the spacing, h 1 , between the boards  120 ,  125  ( FIG. 5 ). Referring again to  FIG. 6 , the height h 1 ′ can to be equal to, or slightly greater than, the combined stack height h 1  of the connector system  360 . Thus, the crest  335  forms a bearing surface to support the mezzanine board  125  at a defined height according to the requirements of the connector system  360 . Any standoffs  145  ( FIG. 2 ) would generally be provided at the same height h 1 ′ so that the installed mezzanine board  125  is substantially parallel to the host board  120 . 
     FIG. 8  shows a perspective view of an alternative embodiment of a connector-alignment collar  400  constructed in accordance with the invention. The connector-alignment collar  400  also includes a base frame  400  coupled at one end to an alignment cantilever  406  and at an opposite end to a guide cantilever  405 . Many aspects of the connector-alignment collar  400  are similar to the connector-alignment collar  150  of  FIG. 6 , with a primary exception of the guide cantilever  405 . Here, the guide cantilever  405  is different, being similar in construction to the alignment cantilever  406 ; that is, the guide cantilever  405  includes an elongated rigid column  420  terminating in a tapered end  415 . Again, the tapered end  415  may include a conical taper as shown. 
   The guide cantilever  405  also includes a reinforcing rib  425  on an exterior side, but the height of the reinforcing rib is limited to the height of the base frame  410  (e.g., the height of the sidewalls), so that the reinforcing rib  425  does not interfere with a guide hole (not shown). Namely, the connector-alignment collar  400  can mate with a mezzanine board having a guide hole, instead of a guide notch, and an alignment hole. The mezzanine board can then be aligned with both cantilevers  405 ,  406  inserted into the respective holes of the mezzanine board. In general, one of the two cantilevers  405 ,  406  can be longer than the other cantilever—here, the guide cantilever is longer than the alignment cantilever—to promote aligning the holes of the mezzanine board with the cantilevers. 
     FIG. 9  shows in more detail a perspective view of the host board connector  155  including a host connector insert  435  within the receptacle base  156 . The host board connector  155  also includes a top support member  440  formed by a portion of the receptacle base  156  that extends above a mating surface of the host connector insert  435  (the insert  435  includes the electrical contacts of the host board connector  155 . The top support member  440  includes the large slot  355   b  and small slot  355   a , which receive the keys  350   a ,  350   b  of the mezzanine board connector  160  when mezzanine board connector  160  mates with the host board connector  155 . 
     FIG. 10A  shows a cross-sectional view of the connector-alignment collar  150  in alignment above the host board connector  155 . The cross-section is in a plane perpendicular to the host board  120  and bisecting the guide cantilever  140  and the alignment cantilever  142 . Two channels  430   a ,  430   b  are formed along the interior surface of the base frame  152  and at a base portion of the cantilevers  140 ,  142 . Each of the channels  430   a ,  430   b  includes a retaining surface  445   a ,  445   b  at one end and a guiding surface  440   a ,  440   b  at the other. Here, the guiding surfaces  440   a ,  440   b  are formed along a bottom edge  450  of the base frame  152 . 
   The receptacle base  156  includes two end-facing projections  448   a ,  448   b , one disposed at each end of the host board connector  155  and extending outwardly therefrom. In some embodiments, the end-facing projections  448   a ,  448   b  are formed along exterior surfaces of the small slot  355   a  and the large slot  355   b , each including a locking surface  455   a ,  455   b  adapted to “snap-fit” into the channels  430   a ,  430   b , respectively. 
   Referring again to the perspective view of the connector-alignment collar  150  of  FIG. 6 , the relative width of one of the channels  430   a  is shown. The width of the channels  430   a ,  430   b  are wide enough to accept the width of the corresponding end-facing projection  448   a ,  448   b.    
   The connector-alignment collar  150  is attachable and detachable from the host board connector  155 , enabling use of the connector-alignment collar  150  with a host board connector of choice. Such a modular approach allows relatively inexpensive connectors to be used in blind mate applications. Being able to add a blind-mate alignment feature in a modular fashion is valuable, because it increases the applications for which such connectors may be used. 
   The connector-alignment collar  150  attaches to the host board connector  155  by urging the bottom edge  450  of the connector-alignment collar  150  against the top of the receptacle base  156 . The top of the lateral projections  448   a ,  448   b  engage guiding surfaces  440   a ,  440   b , directing the lateral projections  448   a ,  448   b  of the host board connector  155  into the channels  430   a ,  430   b , respectively. The connector-alignment collar  150  is urged toward the receptacle base  156 , until the locking surfaces  455   a ,  455   b  snap-fit against the respective retaining surfaces  445   a ,  445   b . Preferably, the channels  430   a ,  430   b  are compliant to facilitate the snap-fit engagement. Engagement of end-facing projections  448   a ,  448   b  with the channels  430   a ,  430   b , may aid with the securing of the connector-alignment collar  150  to the host board connector  155 . Since the host board connector  155  is securely fastened to the host board  120 , the connector-alignment collar  150  is also secured thereto. 
   End-facing projections  448   a ,  448   b  and channels  430   a ,  430   b , may have any of a number of configurations, with a generally rectangular protruding configuration being one preferred example. It should also be noted that the end-facing projections  448   a ,  448   b  and channels  430   a ,  430   b  may be reversed such that end-facing projections  448   a ,  448   b  are formed within the interior surface of the connector-alignment collar  150 , with channels  430   a ,  430   b  formed in the receptacle base  156 . 
     FIG. 10B  shows a cross-sectional view of the connector-alignment collar  150  and host board connector  155  in a mated configuration. In particular, engagement of the locking surfaces  455   a ,  455   b  with corresponding retaining surfaces  445   a ,  445   b  is shown. 
     FIG. 10C  shows the connector-alignment collar  150  manipulated for disengagement from the host board connector  155 . Each of the cantilevers  140 ,  142  includes a beveled surface  460   a ,  460   b  along an outer edge of its base portion. The beveled surfaces  460   a ,  460   b  extend away from the bottom edge  450  and form a rocker bearing allowing the cantilevers  140 ,  142  to pivot in an outward direction from their base portions at the bottom edge  450 . The cantilevers  140 ,  142  are illustrated in an “open” position, with the closed positions shown in phantom. 
   Outward rotation of the cantilevers  140 ,  142  removes interference of the locking surfaces  455   a ,  455   b  from their corresponding retaining surfaces  445   a ,  445   b , such that the connector-alignment collar  150  can be removed from the host board  120  by lifting it away from the host board  120 . (Here, the T-shaped handle  321  of  FIG. 6  can be useful in providing a grip for removing the connector-alignment collar  150  from the host board  120 .) The base frame  152  ( FIG. 10A ) is sufficiently flexible to allow sufficient displacement of the cantilevers  140 ,  142 . In some embodiments, the base frame  152  ( FIG. 6 ) includes a relatively short end wall  340  and corner segment  345  to facilitate flexibility for the cantilever action of the cantilevers  140 ,  142 . The length of the cantilevers  140 ,  142  also facilitates generation of sufficient torque to achieve the pivoting action, such that tools are not required. 
   Additionally, detachability of the connector-alignment collar  150  without tools facilitates preparation of the host board  120  for rework, should that be necessary. In some applications, the connector-alignment collar  150  is integrally formed and made of a plastic. Should the host board  120  require a solder re-flow procedure, removal of the connector-alignment collar  150  might be necessary to prevent it from being damaged (i.e., melted) during the re-flow. 
   While the invention has been shown and described with reference to specific preferred embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the following claims.