Abstract:
A holder is capable of providing flexible support for the connector of a flexible printed circuit board, and has particular applicability for battery recharging cradles for a mobile computing device or hand-held scanner. The holder comprises a receptacle having a rear wall and two side walls, along with protrusions to slidably retain the connector therein. The rear wall connects, using a radiused bend, to a connecting wall, which may form an acute angle relative to the rear wall, and which may neck down to improve rotational capability. The connecting wall transitions, using a radiused bend, to a transverse wall, and from its ends are two cantilever straps extending towards the receptacle, and thereby forming an acute angle relative to the connecting wall. An upward protruding boss on the end of each strap aids translational and rotational flexibility, where the holder is mounted to a surface using orifices in the bosses.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims priority on U.S. Provisional Application Ser. No. 61/203,124 filed on Dec. 18, 2008, and is a continuation of U.S. application Ser. No. 12/653,966, filed Dec. 18, 2009 which issued as U.S. Pat. No. 7,931,494, the disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to improvements in electronic circuitry, and more particularly to apparatus which is capable of providing elastic support for connectors of flexible printed circuit boards. 
     BACKGROUND OF THE INVENTION 
     Flexible electronics, or Flex Circuits, involving the use of flexible printed circuit boards (FPC), represents an innovative technological improvement over conventional printed circuit boards (PCB). These flex circuits are manufactured by mounting electronic devices on flexible plastic substrates, which typically may be polyimide, or a poly(ether-ether-ketone) film (PEEK), or even screen printed silver circuits on polyester. An example of Flexible Printed Circuit Substrate is shown by U.S. Pat. No. 6,858,921 to Kashiwagi. The Kashiwagi FPC claims to feature a high accuracy connecting part that is intended to be attached to the connector, where the connecting part serves to alleviate connection failures “even if a pitch between two adjacent terminals is further reduced.” Other flexible circuit boards are well known in the art. 
     Flexible printed circuits commonly have one or more connectors located upon each end, with the connector having a plurality of terminals, each of which may be electrically connected to the flexible printed circuit board. Often, a connector is configured to encompass the entire end of the FPC, which may not have the special connector of the type shown in Kashiwagi, and where the connector has an actuator that may be pressed down upon to provide electrical contact between the connector and the terminal. An example of such a connector is shown by U.S. Pat. No. 7,581,983 to Yuan. The Yuan connector further features the ability to receive in its entirety, two different flexible printed circuit substrates. 
     Although there are many advantages to circuits utilizing this construction and other types of flexible printed circuits, the adaptability of the board to conform to virtually any desired shape, and to be able to bend or flex even during its use, is most significant. These flex circuits are also advantageously used for electrical connections where either the board dimensions or space constraints are dominant factors. The applications may involve dynamic uses, such as for a folding cell phone, or be advantageously used in static applications particularly in tightly assembled electronic packages where electrical connections are required in three axes. Common uses are for notebook PCs, printers, digital camcorders, digital still cameras, camera modules, PDA units, mobile phones, LCD units, CD-ROM drives, DVD-ROM drives, MiniDisc players, and other compact equipment. Flex circuits may also be used to replace conventional wire harnesses that have typically been used in the aerospace industry for aircraft, rockets, and satellites. 
     In certain applications, mounting of the mating connectors is necessary, so it is common to have an FPC connector fixed to a cradle, but clearances and lead-in on the cradle may introduce forces in the connector during docking of a terminal into the cradle. Also, the user may mishandle the terminal when it is in the cradle, causing severe stress on the connector. 
     This invention serves to solve this problem by housing the connector on a specially adapted holder, which accommodates rotation and translation incurred at extreme positions. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to provide an elastic means of supporting a connector attached to flexible printed circuit board. 
     It is another object of the invention to provide a bracket arrangement for connectors of flexible printed circuits that supplements the flexible character of such devices. 
     It is a further object of the invention to provide an elastic support means for flexible printed circuit connectors that accommodates connector stresses due to misalignment from tolerance build-up eliminating clearances and causing stresses. 
     It is another object of the invention to provide an elastic support means for flexible printed circuit connectors that accommodates mishandling by a user. 
     It is also an object of the invention to provide an elastic support means for flexible printed circuit connectors that accommodates translation of the connector. 
     It is another object of the invention to provide an elastic support means for flexible printed circuit connectors that accommodates rotation of the connector. 
     SUMMARY OF THE INVENTION 
     Many electronic devices today advantageously utilize flexible printed circuits. However, flexible printed circuits ordinarily incorporate connectors on the ends, and in certain applications, mounting of the mating connectors is necessary, so it is common to have an FPC connector fixed to a cradle. However, for some cradles clearances and lead-in on the cradle may introduce forces in the connector during docking of a terminal into the cradle. Also, the user may mishandle the terminal when it is in the cradle, causing severe stress on the connector. 
     This invention serves to solve this problem by housing the connector on a specially adapted holder, which reduces connector stresses by accommodating rotation and translation incurred even for extreme positions. 
     The holder may accommodate multiple degrees of motion, while occupying a compact envelope. The connector of the flexible printed circuit is housed in a receptacle of the holder. The receptacle is configured to have a rear wall and two side walls. The connector may be housed therein using a number of different means. The side walls may have protrusions to retain the connector therein, by snapping the connector into position. Such an arrangement may be deleterious for the connector, therefore the protrusions may be slidably received by the connector, with it being retained by a cover. The side walls of the receptacle may further comprise mounting flanges, each having one or more orifices, which may be used in combination with a fastener to mount the cover. 
     Flexible mounting is accomplished by the remainder of the holder. The rear wall of the holder extends for a certain length and connects, using a radiused bend, to a connecting wall, which may form an acute angle relative to the rear wall, and which may neck down to improve rotational capability. The connecting wall transitions, in one embodiment, using a radiused bend, to a transverse wall, and from its ends are two cantilever straps extending towards the receptacle, and thereby forming an acute angle relative to the connecting wall. A pair of bends in each strap forms a joggle, and an upward protruding boss on the end of each strap aids translational and rotational flexibility, where the holder is mounted to a surface using orifices in the bosses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing hard mounting of a connector, which undergoes undesired deflection, with both the undeflected and deflected positions being shown. 
         FIG. 2  is a first embodiment of the current invention shown supporting a connector that is mounted on a flexible printed circuit. 
         FIG. 3  is a side view of the first embodiment of the current invention. 
         FIG. 4  is an auxiliary view of the connecting wall of the first embodiment of the current invention, having the full rectangular width for the entire connecting wall. 
         FIG. 5  is an auxiliary view of the connecting wall of a second embodiment of the current invention, having the rectangular width of the connecting wall neck down. 
         FIG. 6  is a section cut through the necked down area of the connecting wall of the second embodiment, with the necked down area having a square cross-section. 
         FIG. 7  is a section cut through the necked down area of the connecting wall of a third embodiment in which the necked down area has a round cross-section. 
         FIG. 8  is an auxiliary view of the connecting wall of a fourth embodiment of the current invention, having the rectangular width of the connecting wall neck down, but also having a rectangular-stiffened cross-section. 
         FIG. 9  is a section cut through the necked down area of the connecting wall of the fourth embodiment. 
         FIG. 10  is the first embodiment of the current invention shown installed with a Z-support bracket to provide back-up hard stops for excessive deflection. 
         FIG. 11  is a schematic representation of the flexible dynamic response afforded the flexible printed circuit connector when mounted in the first embodiment of the current invention. 
         FIG. 12  is a mobile computing device which may be inserted into a cradle having a electrical connector flexibly supported by the holder of the current invention. 
         FIG. 13  is an illustration the mobile computing device of  FIG. 12  being slidably held in a cradle that has a connector mounted therein using the holder of the current invention. 
         FIG. 14  is an illustration of a cradle with a rubber bumper that may provide a cushion and clearance for slidably reception of the mobile computing device within the cradle, without stressing a connector. 
         FIG. 15  is an illustration of the cradle of  FIG. 14  where the rubber bumper has been deformed so as to eliminate all clearance between the terminal and the cradle, which may deflect a mating connector. 
         FIG. 16  shows a section view of the holder of the present invention mounted to a cradle and supporting a connector therein with a gap between the connector and cradle. 
         FIG. 17  shows a section view of the holder of  FIG. 16  where the connector and holder have been deflected to eliminate the gap. 
         FIG. 18  shows a connector mounted to a cradle using the holder of the present invention, with the connector protruding up from the cradle. 
         FIG. 19  shows a perspective view of the bottom of a cradle with the holder of the present invention mounted to the cradle. 
         FIG. 20  shows a perspective view of the bottom of a cradle with the holder of the present invention mounted to the cradle, and with a Z-bracket mounted therein to limit travel of the holder of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a perspective view of an example installation  10  with conventional hard mounting of an undeflected connector  11 , and when loads are applied to the undeflected connector  11 , it undergoes undesired deflection and results in the stressed connector  12 . The stress experience by connector  12  may result in the disconnection of certain terminals within the connector, and improper functioning of the unit. 
       FIG. 2  illustrates one embodiment of the holder  20  of the present invention, which is a uniquely formed bracket capable of providing releasable support for connector  11 , and flexible mounting of the connector  11  within, and relative to, a cradle  102 .  FIG. 12  shows a pair of gun-shaped mobile computing devices,  100  and  101 , which are shown merely to be illustrative of one type of application for which the holder or bracket of the present invention may be beneficial.  FIG. 13  illustrates one of the mobile computing devices  100 / 101  being held in a cradle  102 , where a connector  101 A (general location shown in  FIG. 12 ) in the mobile computing device  100  may be slidably received by the connector held by the holder  20  of the current invention that may be mounted to the cradle  102 . 
     The holder  20  may be manufactured of any suitable material for a particular application, and thus may be metallic, plastic, or even wood. Holder  20  may be manufactured as a single part, as shown in  FIG. 2 , or may be formed from an assembly of two or more parts. The complex shape of the single part shown in  FIG. 2  may best be formed as an injection molded part, but could also be a sheet metal part with multiple bends. 
     The first embodiment of the holder  20  of the present invention may have a receptacle  21  for providing direct support for the electrical connection H. The receptacle  21  may be formed using a rear wall  22 , which is generally flat. Extending outward from the rear wall  22  may be a first side wall  23  and a second side wall  24 . The first and second sidewalls  23  and  24  may generally be parallel to each other and be orthogonal to the rear wall  22 . The combination of first and second side walls  23  and  24  and rear wall  22  may serve to create a three-sided enclosure into which the electrical connector may be releasably retained. The first and second side walls  23  and  24 , and rear wall  22  may work in combination with other features to support and retain the connector  11  in the receptacle  21 , including, but not limited to, incorporating flexible protrusions or using a cover plate. 
     Flexible protrusions  25  may protrude out from the first side wall  23  and second side wall  24  to be snapped into, or retained by, a groove or recess in the connector  11 , and maintain the connector in close proximity to the rear wall  22 , and generally centered between first and second side walls  23  and  24 . The height of the protrusions may depend upon the connector supported or upon the material utilized. Even where the holder  20  is formed from metal or plastic, the protrusions  25  may be formed from that same material, but more preferably may be formed of a rubberized material. 
     Support for the cover may also be provided by a cover  15 . The first and second side walls  23  and  24  may each have a mounting flange  26  and  27 , where the flanges  26  and  27  are generally orthogonal to the first and second side walls. The mounting flanges  26  and  27  may each have one or more orifices  28  that are capable of receiving a fastener (not shown) to mount the cover  15 . A nut and bolt arrangement (not shown) may be utilized to install the cover, or alternatively, the orifices  28  may be internally threaded so the cover can be mounted with only the use of a bolt. 
     The cover  15  may engage a recess on one side of the connector  11 , while the rear wall may have a lip (not shown) that similarly engages a recess on the other side of the connector. The engagement by the cover and the lip may be set to provide clearance so as not to clamp-up upon the connector  11 , and potentially cause damage. The portion of the cover  15  that engages the connector  11 , and the lip on the rear wall  22  may thus be preferably made of a rubberized material. Also, to provide a rigid receptacle that may protect the connector  11 , the first side wall  23  and the mounting flange  26 , as well as the second side wall  24  and the mounting flange  27  may have stiffening walls  29  and  30 , respectively. 
     Mounting of the connector  11  in the receptacle  21  will result in flexible support by way of the configuration of the remainder of the holder  20 . The configuration of holder  20  further comprises rear wall  22  extending for a certain length to join a connecting wall  32 . Rear wall  22  and connecting wall  32  may be joined by a radiused bend  33 . The radiused bend  33  may preferably be a generous radius to promote flexure between the rear wall  22  and the connecting wall  32 . 
     The connecting wall  32  may also be of a certain length before it transitions into a transverse wall  34 . Connecting wall  32  may transition into transverse wall  34  using a radiused bend  35 . The radiused bend  35  may preferably also be a generous radius to promote flexure. Transverse wall  34  may preferably have a first end  36  and a second end  37  extending beyond the ends of connecting wall  32 . Extending from the first end  36  and second end  37  may be cantilevered straps  39  and  45 , respectively, which may protrude generally orthogonally away from the transverse wall  34  and back towards the receptacle  21 , as seen in  FIGS. 2 and 3 . There is preferably a gap  38  between the radiused bend  35  and each of the straps  39  and  45 , in order to improve rotational flexure as described hereinafter. 
     The strap  39  may preferably have a joggled step that is formed by a first bend  40  and a second bend  41 , so that the free end of strap  39  is offset from the transverse wall  34  and may be generally parallel to the transverse wall  34 . The strap  39  may terminate in the free end  42  which may be rounded, and which may have a boss  43  protruding upward therefrom. The boss  43  may have an orifice  44 , which may be used for the mounting of holder  20 . Strap  45  may be similarly be formed with a first bend  46 , and second bend  47 , and having a free end  48  with upward protruding boss  49  that has an orifice  50 . However, rather than utilizing an orifice in each of the straps  39  and  45 , the holder may be mounted through a welding process or some other means of mechanically clamping the holder to a mounting surface. 
     As seen in  FIGS. 16 and 17 , a connector  11  may be retained within the holder  20 , and the holder  20  may be mounted to a cradle  102  of a charging device or other kind of device. The opening in the cradle  102  is preferably oversized at least 2 mm larger that the connector  20  to permit deflection of the connector  11  relative to the cradle  102 . To prevent excessive deflection of the bracket, a travel-limiting bracket  103  may also be attached in conjunction with the holder  20  attachment to the cradle ( FIG. 20 ) to inhibit excessive deflections of the holder  20 . 
     In an alternate embodiment, the generally flat and rectangular connecting wall  32 , as seen in perspective view in  FIG. 2  and in the true view in  FIG. 4 , may neck down ( FIG. 5 ). The connecting wall would then consist of a first generally rectangular region  60  and a second generally rectangular region  61  that are separated by a neck  63 . The neck area  63  may simply have a square cross-section as seen in  FIG. 6 , or in a third embodiment, it may be tailored to have a circular cross-section, as seen in  FIG. 7 , which may gradually transition into the planar rectangular regions  60  and  61 . The square cross-section could be grown in the plane of the wall to be rectangular, and therefore be more resistant to fatigue failure, but such increases would tend to decrease rotational flexure as herein discussed. 
     In a fourth embodiment, the neck  63  may have a stiffener  64  with a rectangular cross-section that is generally transverse or orthogonal to the plane of the connecting wall. Stiffener  64  may preferably extend onto a least a portion of the planar rectangular regions  60  and  61 . The thickness for the stiffener  64 , as well as each of the walls utilized, may be tailored to provide for flexure for specific installation requirements, and according to the material used in manufacturing the holder. The stiffness, and thus flexure, may also be changed by changing the lengths of certain members. 
     It can be seen that mounting of the holder  20 , with a connector releasably retained by the receptacle  21 , using screws or bolts etc. through orifices  44  in the bosses  43  and  49  to attach the holder, produces a very flexible supporting arrangement. The arrangement is capable of accommodating multiple degrees of motion with loads applied upon the connector, to reduce stresses and yielding of the connector, and lessen the potential for damage to one or more terminals. The flexure which may be accommodated by holder  20  may be translation in the X, the Y, and/or the Z direction (see the axes depicted on  FIG. 2 ), and well as rotational movement about each of those axes or some combination. As stated previously, the amount of flexure that may be safely accommodated may depend on specifics of each design, however, as shown in  FIGS. 2 and 10 , the holder  20  may be capable of supporting translations or more than 0.5 inches along each of the axes. 
     Rotation about the X axis may be seen to be accommodated by the cantilevered straps  39  and  45  working in conjunction with the bosses  43  and  49 . A rotational force applied to the connector  11  may be accommodated by the strap  39  deflecting upward towards the mounting surface  13  ( FIG. 10 ), the clearance for which is provided by the offset achieved with to the height of boss  43 , while the strap  45  may deflect downwards, and wherein the transverse wall may be angled relative to its rest position. Counter-rotation about the X axis may similarly be accommodated by downward deflection of the strap  39  and upward deflection of strap  45 . 
     Rotation about the Y axis may be seen to be accommodated by the flexure of the rear wall  22  relative to the connecting wall  32 , and flexure of the connecting wall  32  relative to the transverse wall  34 . In this respect, the affect of material thicknesses utilized and the lengths of the wall members may have more of a pronounced effect upon the capability of the holder to support increasing Y-rotational movements, as compared with rotation about the other axes. However, rotation movement about the Y axis is also accommodated by simultaneous deflection of the straps  39  and  45 , in either the upward or downward direction. Also, a significant gap  38  between the radiused bend  35  and each of the straps  39  and  45  would promote greater rotational flexure by further permitting torsional defection of the transverse wall  34  relative to the straps  39  and  45 . 
     Rotation about the Z axis may be seen to be accommodated by the flexure of the connecting wall  32 , particularly where it transitions to have a neck  62  separating two generally rectangular regions  60  and  61 , as seen in  FIG. 5 . The necked down arrangement of  FIG. 5 , while providing much flexural capability, may be prone to fatiguing and breakage. Therefore, the neck  62  may have a stiffener  63 , which would not greatly inhibit flexural capability about the Z axis. 
     While the deflections which may be accommodated by the holder  20  may be quite large, they may ultimately be excessive in relation to other aspects of the overall design of the unit. In such cases, fixed stops may be incorporated into the unit itself, or alternatively be added to the holder  20 . The unit may also, as described previously, be designed to reduce flexural capability and potential deflections by increasing thicknesses and reducing member lengths. 
     The examples and descriptions provided merely illustrate a preferred embodiment of the present invention. Those skilled in the art and having the benefit of the present disclosure will appreciate that further embodiments may be implemented with various changes within the scope of the present invention. Other modifications, substitutions, omissions and changes may be made in the design, size, materials used or proportions, operating conditions, assembly sequence, or arrangement or positioning of elements and members of the preferred embodiment without departing from the spirit of this invention.