Abstract:
A circuit board support operable with boards requiring a horizontal motion for engagement of connectors. The support can be exchanged for a traditional standoff and screw combination without modification of the board or supporting structure.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to the field of circuit board mounting, and, in particular, to fastenerless circuit board support systems. 
     BACKGROUND 
     Circuit board design involves not only electrical considerations but also numerous mechanical considerations. One important mechanical consideration is the provision of an adequate board mounting system. Depending upon the design objective, some board supports may advantageously be electrically connected to a supporting structure, and some board supports be insulated. Modifications after fabrication of the board and the supporting structure are often prohibitively expensive. When using mounting elements having threaded fasteners, such a change is often labor intensive since later changes require removal of the circuit board, replacement of the mounting elements and reinstallation of the board. In addition, mounting system modifications often entail altering the circuit board and the support structure. 
     What is needed in the art is an inexpensive mounting system allowing simplified modifications and requiring no threaded fasteners. 
     SUMMARY 
     The above mentioned problems associated with mounting systems, and other problems, are addressed by the present invention and will be understood by reading and studying the following specification. 
     In particular, an illustrative embodiment of the present invention includes a device comprising a base, a first rigid tab, a flexible tab, a pedestal and a board hook. The base includes a planer surface lying in a plane substantially parallel to the plane of a support structure. The base includes a longitudinal axis with a first end and a second end. The first rigid tab includes a first standoff affixed to the base and a first catch affixed to the standoff The first catch engages a first edge of the support structure upon movement of the device, relative to the support structure, in a direction towards the first end. The flexible tab extends towards the second end and has flexibility to allow deflection in a direction normal to the planer surface. The flexible tab includes a portion that intersects the plane of the planer surface. The pedestal is affixed normal to the base and extends in a direction opposite that of the first rigid tab. The pedestal includes a board support surface substantially parallel to the plane of the planer surface. The board hook is affixed to the pedestal and engages a first edge of the board upon movement of the board, relative to the device, in a direction towards the first end. 
     In one embodiment, the first rigid tab and the flexible tab lie along the longitudinal axis. In one embodiment, the board includes an electrical connector adapted to mate with a matching connector upon relative movement of the electrical connector and the matching connector over a distance having a predetermined length. The matching connector is coupled to the support structure, and the board hook has a slot having a length greater than the predetermined length. In one embodiment, the board support surface is insulated from the base. In one embodiment, the device includes insulative material. In one embodiment, the device is fabricated of insulative material. In one embodiment, the rigid tab standoff and the hook are aligned on an axis normal to the planer surface of the base. In one embodiment, the flexible tab is adapted to resist forces applied in directions lying in the plane of the planer surface. In one embodiment, present subject matter provides a second rigid tab including a second standoff affixed to the base and a second catch affixed to the second standoff. The second catch engages a second edge of the support structure upon movement of the device, relative to the support structure, in a direction towards the first end. In one embodiment, the second rigid tab lies on the longitudinal axis. 
     In an alternative embodiment, the present subject matter provides a method for mounting a circuit board, the method comprising providing a support structure, providing a fastener, engaging the fastener, deflecting a flexible tab of the fastener, engaging the flexible tab of the fastener, positioning a circuit board and displacing the circuit board to engage the fastener. The support structure has first edge and a second edge. Engaging the fastener includes engaging with the first edge of the support structure. Engaging the flexible tab of the fastener includes engaging with the second edge of the support structure. 
     In one embodiment, providing a support structure with a first edge and a second edge includes providing a support structure with a third edge, and the method further comprises engaging the fastener with the third edge of the support structure. In one embodiment, displacing the circuit board to engage the fastener includes engaging an electrical connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A illustrates a view of a screw and standoff combination. 
     FIG. 1B illustrates an isometric view of the present system. 
     FIGS. 2A,  2 B and  2 C illustrate three views of the system of FIG.  1 B. 
     FIGS. 3A and 3B illustrate views of the circuit board hole pattern and support structure hole pattern, respectively, for one embodiment of the present system. 
     FIG. 4 illustrates a circuit board with one embodiment of the present subject matter. 
     FIG. 5 illustrates a side view of one embodiment of the present system with a circuit board and supporting structure. 
     FIGS. 6A,  6 B,  6 C and  6 D illustrate views of one embodiment of the present system. 
     FIG. 7 illustrates a flowchart for the assembly of a mounting system in accordance with one embodiment of the present subject matter. 
     FIG. 8 illustrates a flowchart for the disassembly of a mounting system in accordance with one embodiment of the present subject matter. 
     FIGS. 9A,  9 B, and  9 C (hereinafter collectively referred to as FIG. 9) illustrate dimensions for one embodiment of the present system. 
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings which form a part of the specification. The drawings show, and the detailed description describes, by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be used and mechanical and electrical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. Like reference numbers refer to similar items in all the figures. 
     FIG. 1A illustrates a screw and standoff assembly for mounting a circuit board relative to a support structure. Screw  105  passes through hole  110  in circuit board  125 , standoff  135 , support structure  155  and is threaded on nut  165 . Screw head  100  is in contact with the top surface  120  of board  125 . Upper end  115  of standoff  135  is in contact with the lower surface  130  of board  125 . Bore  140  in standoff  135  provides clearance for the shank of screw  105 . Lower end  145  of standoff  135  is in contact with the upper surface  150  of support structure  155 . Nut  165  is in contact with lower surface  160  of support structure  155 . Threads  170  of screw  105  secure the assembly. 
     Installation or removal of the standoff in FIG. 1A requires access to both nut  165  and screw head  100 . In addition, alignment of standoff  135  with board  125  and structure  155  must be maintained during the installation process. 
     In cases requiring the board to be insulated from the support structure, insulative sleeves, washers, or fasteners may be used. In cases requiring the board to be electrically coupled to the support structure via the mounting system, conductive standoffs, conductive fasteners and other techniques may be used. Converting an insulated mount to a conductive mount, or visa versa, entails modification of the board or additional or substituted fastener systems. 
     FIG. 1B illustrates one embodiment of device  200  of the present system. A center line, extending along the longitudinal axis, is marked  205  in the figure. Base  210  is coupled to pedestal  225  and pedestal  220 . One portion of pedestal  220  is visible in FIG. 1B and a second portion of pedestal  220  is hidden from view. Board stop  235  and board stop  230  are visible on the upper surface of pedestal  225  and pedestal  220 , respectively. Slot  240  is aligned horizontally and defined by the board stop  235  and hook  245 . In the embodiment shown, hook  245  is affixed to a section of pedestal  225  and  220 . Chamfer  250  is visible on the sides of hook  245 . 
     Base  210  includes a lower surface  215 . In the embodiment shown, lower surface  215  lies in a plane substantially orthogonal to pedestal  225  and pedestal  220 . A first end of flexible tab  260  is coupled to base  210  at surface  270 . End  265  of flexible tab  260  engages the support structure, as described subsequently. 
     FIG. 2A illustrates a side elevation view of one embodiment of device  200 . The alignment of base  210  relative to other elements is visible in the figure. For example, horizontal slot  240  is seen to be substantially parallel with the plane of lower surface  215  of base  210 . Beveled edge  250  is visible on hook  245 . In addition, board stop  230  and board stop  235  are also substantially parallel with surface  215 . In the embodiment shown, flexible tab  260  extends substantially parallel with surface  215 . End  265  intersects with, and descends below, the extension of the plane of surface  215 . Flexible tab  260  tolerates slight deflections in directions normal to the plane surface  215 . In particular, flexible tab  260  can be deflected, without permanent deformation, such that end  265  no longer intersects with the extension of plane surface  215 . Upon removal of external forces acting on device  200 , flexible tab  260  returns to a position wherein the end  265  is below the extension of plane surface  215 . 
     A first rigid tab extends downward from surface  215  of one end of base  210 . The first rigid tab includes standoff  290  and catch  285 . Standoff  290  and catch  285  form throat  280 . Throat  280  is defined by standoff  290 , catch  285  and base  210 . Selected edges of catch  285  are beveled and herein marked  295 . 
     A second rigid tab extends downward from surface  215  of a second end of base  210 . The second tab includes standoff  275  and catch  300 . Standoff  275  and catch  300  form throat  305 . Throat  305  is defined by standoff  275 , catch  300  and base  210 . Selected edges of catch  300  are beveled and herein marked  310 . 
     FIG. 2B illustrates an end view of one embodiment of device  200 . Lateral axis  315  is visible in the figure. Base  210  is substantially orthogonal to lateral axis  315 . Pedestal  220  and board stop  230  are also visible in the figure. 
     FIG. 2C illustrates a bottom view of one embodiment of device  200 . Longitudinal axis  205  is visible in the figure. In the embodiment shown, the substantially linear alignment of end  265 , catch  300  and catch  285  is visible. Edge chamfers  310  and  295 , of catch  300  and  285  are also visible in the figure. Dimension L′ denotes the overall diameter of catch  285 . 
     In the embodiment shown, catch  300  is substantially rectangular in shape. Other geometric shapes are also contemplated, including but not limited to, circular, semi-circular, oblong, or triangular. 
     In the embodiment shown, catch  285  is substantially circular in shape with flat sides aligned with the longitudinal axis. The diameter of the circular portion is denoted by letter L′. Other geometric shapes are also contemplated, including but not limited to, rectangular, oblong, or triangular. 
     In the embodiment shown, flexible tab  260  has rectangular cross-section and angled sides. Other tab shapes are also contemplated, for example, in one embodiment,  260  is a linear rod member. 
     FIG. 3A illustrates the hole pattern for a circuit board suitable for use with one embodiment of device  200 . The pattern shown in the figure is viewed from above, meaning that device  200  is positioned below the image and hook  245  extends upward through the circuit board. The geometric shapes in the figure represent openings in the surface of the circuit board. 
     Dimension A of FIG. 3A signifies the length of the rectangular opening in the circuit board. The rectangular opening accepts hook  245  of device  200 . Dimension A of FIG. 3A is at least large enough to accept the overall length of hook  245 , as denoted by dimension A′ of FIG.  2 A. Dimension B of FIG. 3A signifies the width of the rectangular opening and is at least large enough to accept the width of hook  245 , as denoted by dimension B′ of FIG.  2 B. The rectangular dimensions of the opening in the circuit board may deviate from those explained herein. When the board is assembled with device  200 , hook  245  captivates the board in the area denoted by the head end of arrow C of FIG.  3 A. In addition, the lower surface of the circuit board is supported by board stop  230  (in the area denoted generally by arrow E and arrow D) and board stop  235  (in the area denoted generally by arrow C). 
     FIG. 3B illustrates the hole pattern for a support structure suitable for use with one embodiment of device  200 . The pattern shown in the figure is viewed from above, meaning that device  200  is positioned from above the image and catches  300  and  285  extend downward through the support structure. The geometric shapes in the figure represent openings in the surface of the support structure. It will be noted that in the embodiment shown, the hole pattern in the support structure lies along the longitudinal axis  205 . 
     Dimensions F and G of FIG. 3B signify the width and length, respectively, for end  265  of flexible catch  260 . Dimensions F and G of FIG. 3B must be at least as large as dimensions F′ and G′ of FIG.  2 C. Dimensions J and H of FIG. 3B signify the width and length, respectively, for catch  300  of device  200 . Dimensions J and H of FIG. 3B must be at least as large as dimensions J′ and H′ of FIG.  2 C. Dimensions K and L of FIG. 3B signify the width and diameter, respectively, for catch  285  of device  200 . Dimensions K and L of FIG. 3B must be at least as large as dimensions K′ and L′ of FIG.  2 C. The dimensions outlined in this paragraph are to be considered minimum dimensions for the hole pattern. The dimensions in the support structure may deviate from those explained herein. 
     In one embodiment, when device  200  is assembled with the support structure, catch  285  and catch  300  captivate device  200  in the area denoted by the head end of arrows M and N, respectively, of FIG.  3 A. In addition, flexible tab  260  relies upon strength in the area of arrow P to resist movement tending to remove device  200  from the support structure. Planer surface  215  also is in contact with the support structure in the region surrounding the openings shown in FIG.  3 B. 
     Variations in the hole template and patterns are possible. For example, in FIG. 3C, the support structure may be fabricated with two openings rather than the three shown. In one embodiment, the web between the opening having dimensions F×G and the opening having dimensions J×H is eliminated to create a single large opening. 
     In FIG. 4, circuit board  125  is shown with device  200 . Circuit board  125  includes opening  330 . In the embodiment shown, opening  330  is of rectangular shape and adapted to receive hook  245 . Hidden lines beneath the board identify various features of device  200 . For example, board stop  230  and board stop  235  are illustrated. 
     In FIG. 4, one end of circuit board  125  is coupled to an edge connector  340 . In the embodiment shown, the edge connector is mounted on an edge substantially perpendicular to longitudinal axis  205  of device  200 . Other types of connectors, such as a surface connector, and different placement of a connector, are also contemplated. 
     In one embodiment, circuit board  125  and device  200  are assembled by moving circuit board  125  in the direction indicated by arrow  345 . Arrow  345  also corresponds with the direction of movement for mating electrical connector  340  to a matching connector. The length of the throat of device  200  is longer than the sliding distance required to mate the electrical connector. This arrangement assures that full electrical connection is established without limitation by device  200 . 
     FIG. 5 illustrates a view of an embodiment of the present mounting system. In the figure, device  200  is shown in dashed lines, having been cut on the center line shown in FIG. 2B, marked  315 . In addition, an edge view of circuit board  125  and an edge view of support structure  350  is illustrated. Device  200  is shown installed on support structure  350  and circuit board  125  is installed on device  200 . As previously discussed, the throat area formed by hook  245  and pedestal  225  engages an edge of board  125 . Opening  330  provides clearance to receive hook  245 . Also in the embodiment shown, planer surface  215  lies along the upper surface of support structure  350 . Flexible tab end  265  extends below the planer surface. During installation of device  200  onto support structure  350 , end  265  is deflected in an upward direction. Upon engagement of catch  300  and catch  285  on the edges of corresponding openings in support structure  350 , end  265  snaps into the opening in structure  350 . In the embodiment shown, end  265  has an angled portion that engages an opening in structure  350 . In various embodiments, end  265  has a radius portion or a straight portion. 
     FIG. 5 also indicates alignment of the various openings in one embodiment of the present mounting system. Line  360  extends through opening  330  in circuit board  125  as well as an opening in support structure  350 . One of skill in the art will recognize that a standoff and screw combination can be inserted in the area denoted by line  360 , in lieu of device  200 . A standoff and screw combination may be used in applications requiring a mounting having threaded clamping action. In addition, a standoff and screw combination may be used in applications requiring a conductive or insulative mounting. 
     FIGS. 6A,  6 B and  6 C illustrate another embodiment of the present subject matter. FIG. 6D illustrates an isometric view of the embodiment of FIGS. 6A,  6 B and  6 C. The embodiment shown includes hook  245  and flexible tab  260 . Pedestal  420  is of circular cross section and has board stop  425  and planer surface  430 . Catch  410  extends below planer surface  430  and has throat  435  directed in a direction opposite that of throat  440  defined by hook  245 . The vertical alignment of the opening that receives catch  410  (in support structure  350 ) and the opening that receives hook  245  (in circuit board  125 ) enables replacement of device  200  with a screw and standoff combination. Proximate to flexible tab  260  is alignment pin  400 . Alignment pin  400 , in the embodiment shown, has a round cross section, however other shapes are also contemplated. In addition, alignment pin  400  may be located in another position on planer surface  430 . For example, pin  400  may be located opposite flexible tab  260 . 
     FIG. 7 illustrates a flowchart for a method of assembly of one embodiment of device  200  in a particular application. At  505 , the method calls for providing a support structure having a catch opening and a tab opening. In one embodiment, the openings are depicted in FIG.  3 B. At  510 , device  200  is positioned in a manner that aligns the catch and tab with the openings of the support structure. The catch of device  200  is inserted in the opening until contact with the planer surface  215  of base  210  is established. Insertion also includes deflection of flexible tab  260  upon contact of end  265  with the support structure. At  515 , device  200  is slid in a direction opposite that of flexible tab  260 . At  520 , continued sliding action results in engagement of the throat of the catch with the edge of the opening in the support structure. The sliding action also causes end  265  to approach, and eventually fall into, one of the openings of the support structure. At  525 , the method calls for provision of a circuit board having an opening for hook  245 . At  530 , the opening of the board is aligned with the hook and the board is placed over the hook. The board is lowered onto device  200  until contact is made with board stop  230  and board stop  235 . At  540 , the board is slid in a direction to engage the hook on the edge of the opening in the board. Since the direction of the throat on the catch is opposite the direction of the throat on the hook, sliding to engage the hook tends to reinforce the engagement of the catch. In one embodiment, the board is slid a distance of approximately 0.200 inches, which corresponds to the length of the throat of hook  245 . At  545 , the method of installation is completed. 
     FIG. 8 provides a method for disassembly of one embodiment of the present subject matter. At  600 , it is assumed that board  125  has been removed from device  200 . At  605 , end  265  of flexible tab  260  is raised. End  265  can be raised by numerous methods. For example, end  265  can be raised by insertion of a tool or object in the lower side of the opening of the support structure. End  265  can also be raised by prying or lifting flexible tab  260 . In one embodiment, a ridge is provided on an edge of end  265  for receiving a lifting tool to facilitate raising of end  265 . At  610 , the device is slid in a direction to disengage the catch from the edge of the opening in the support structure. At  615 , device  200  is raised clear of the openings in the support structure. The method ends at  620 . 
     Device  200  may be fabricated using injection molding, die casting, or other known methods of fabrication. Device  200  may be fabricated from plastic or other insulative material. In one embodiment, device  200  is fabricated of LEXAN® 500 (PC-ABS, 10% glass reinforced). LEXAN is a registered trademark of General Electric Company, 1 River Road Schenectady, Mass. Strength and flexibility requirements of flexible tab  260  may warrant the use of particular materials. 
     FIG. 9 depicts typical dimensions, in inches, for one embodiment of device  200 . The dimensions shown are exemplary only and not to be taken in a limiting sense. The embodiment shown in FIG. 9 includes a fore and aft catch, and a flexible tab for anchoring device  200  in a support structure. As explained herein, the flexible tab holds device  200  immovable during installation and removal of board  125 . 
     CONCLUSION 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention.