Abstract:
A grip for holding a tablet computer in one hand while activating and using the device with the other hand comprises a stem connecting a base portion attached to the tablet and a top portion, with a central hole of appropriate size in the stem to accommodate a finger inserted through the grip. Opposing walls of the stem are biconcave in the plane perpendicular to the plane of the hole in the stem, defining a shape convenient for gripping between two fingers.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 13/802,580, now U.S. Pat. No. 8,672,374. 
     BACKGROUND OF THE INVENTION 
     Tablet display devices have become popular consumer products for use in a variety of applications. Many such devices are flat, thin computers with a display panel on most of the area of one surface. Although the majority of these incorporate the computational, communication and display circuitry of a general purpose computer, some are more specialized for limited functionality, such as readers for electronic books or special map or industrial data displays. Typical dimensions are 8 in×10 in×½ in (similar to a tablet of paper) and 8 in×6 in×⅓ in (for so-called “mini” tablets), with weights ranging from about 2 pounds to just over ½ pound. 
     Wireless telephone communication devices with computer circuitry, known as “smartphones” have similar relative dimensions, but on a smaller scale. A growing trend has been to offer smaller tablets on the one hand and larger smartphones on the other, so that the sizes of the respective devices may converge. As used herein, the term “tablet computer” shall refer to any thin handheld device with a display panel on one surface and circuitry to generate a display on that surface. 
     Many uses involve operating the tablet computer while standing. While a tablet is light enough to hold in the hand, using it for any length of time may be tiring. A touch screen is operated with the fingers of the dominant hand, while the tablet is grasped with the other hand by its edge. The weight of the unit is applied to a moment arm that makes the user&#39;s grip difficult to maintain for an extended period of time. The tablet computer usually has a flat back that can be supported on the open palm of the off hand, but balancing the device is difficult while the touch screen is being activated. 
     The present invention addresses a need for a convenient way to hold a tablet computer in one hand while activating it with the other. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides a compact and convenient way to hold a tablet computer in one hand while activating and using the device with the other hand. The device, as seen in  FIG. 1 , is a small grip and stand that is to be attached at the approximate center of the tablet on the back, or underneath, side. In one embodiment, it is removably attachable to the tablet, and can serve as a handle or a small stand that elevates the tablet at a slight angle. A stem connects a base portion attached to the tablet and a top portion. A central hole of appropriate size in the stem accommodates a finger inserted through the grip. Opposing walls of the stem are biconcave in the plane perpendicular to the plane of the hole in the stem, defining a shape convenient for gripping between two fingers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of one embodiment of the invention; 
         FIG. 2  shows an end view of the embodiment of  FIG. 1 ; 
         FIG. 3  shows an end view of the embodiment of  FIG. 1 ; 
         FIG. 4  shows a side view of the embodiment of  FIG. 1 ; 
         FIG. 5  shows a position of a user&#39;s hand when using an embodiment of the invention; 
         FIG. 6  shows an alternative position of a user&#39;s hand when using the embodiment of  FIG. 6 ; 
         FIG. 7  shows a cross section through the center of the embodiment of  FIG. 1 ; 
         FIG. 8  is a perspective view showing a cavity in the base of an embodiment of the invention; 
         FIG. 9  shows an embodiment of the invention that uses a tablet back cover to secure the holder to the tablet, with the holder and cover separated; 
         FIG. 10  shows the embodiment of  FIG. 9  with the holder in place in the back cover; 
         FIG. 11  shows an embodiment of the invention with a design disc in place. 
         FIG. 12  shows an embodiment of the invention that uses a clip mechanism to attach the holder to the tablet. 
         FIG. 13  shows a top view of a retainer ring used in the embodiment shown in  FIG. 12 . 
         FIG. 14  shows a cross section of the base of the embodiment shown in  FIG. 12 , with a cross section of the retainer ring. 
         FIG. 15  shows a cross section of the base of the embodiment shown in  FIG. 12  with the attachment unit in place. 
         FIG. 16  shows one version of an attachment unit for use with the embodiment shown in  FIG. 12 . 
         FIG. 17  shows a different version of an attachment unit for use with the embodiment shown in  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     One embodiment of the invention is shown in  FIGS. 1-3 . The holder  1  comprises a base  10 , a top  2 , and a pair of vertical support elements,  3  and  4 , connecting the base  10  with the top  2 . The top  2  has a lower surface  5  and an upper surface  6 . The base has a lower surface  7  and an upper surface  8 . The vertical support elements have facing inner surfaces  11  and  13  and outwardly facing surfaces  12  and  14 . Each also has outwardly facing surfaces  15  and  16  in a plane orthogonal to the plane of inner surfaces  11  and  13 . See  FIG. 4 . 
     In this embodiment, the interior surfaces of the top, bottom, and sides define a generally-circular aperture space  9  sized to accept the insertion of a finger. The user can insert his finger with his palm toward the tablet, as in  FIG. 5 , or away from the tablet. A diameter of about 0.9 in is a good compromise for the size of aperture  9 , but other dimensions may be desirable in particular applications. For example, it may be advisable to create three or more standard apertures to accommodate the different hand sizes of men, women and children. 
     As may be seen in  FIGS. 1-4 , the vertical support elements  3  and  4  are curved inward in three directions, appearing as a triconcave pillar connecting the base and the top. The vertical support elements  3 ,  4  are concave in the plane of the finger aperture  9 , each combining with the inner surface  5  of the top  2  and inner surface  8  of base  10  to define an approximate circle. In the plane perpendicular to the plane of the finger aperture, the vertical support elements are biconcave, defining back to back approximate half circles  17 ,  18  perpendicular to the finger aperture  9  with approximate diameters slightly larger than that of the finger aperture. The user may grasp the holder between two fingers, partially encased by the half circles, to comfortably support the tablet with one hand. See  FIG. 6 . In an embodiment, the outwardly facing surfaces  12  and  14  in the plane of the finger aperture  9  are relatively straight. These surfaces may take any shape consistent with the need for structural support of the top  2 . 
     The holder device is attachable to the back of a tablet computer, and preferably is removably attachable. In one embodiment, attachment is accomplished using a pair of magnetic discs. See  FIGS. 7 and 8 . A holder magnet  25  is affixed in a cavity  21  in the base  10  of the holder device. The cavity  21  is just deep enough to envelop both the holder magnet  25  and a tablet magnet  26  affixed to the back of the tablet. In an embodiment, the base  10  is circular and the holder magnet  25  and the tablet magnet  26  are circular discs, a configuration that permits easy orientation of the finger aperture  9  when the holder is attached to the tablet. 
     In an embodiment, the holder magnet  25  and tablet magnet  26  are plated magnetic discs, each about 0.125″ thick, with attracting poles directed toward each other, providing a strong bond that can be broken with the deliberate application of moderate force. In another embodiment, the holder magnet  25  is a strong magnetic disc and the tablet attachment component  26  is a  16  gauge polished steel disc or a magnetic metal of suitable thickness. Known pressure sensitive adhesive tapes or materials may be used to affix the tablet attachment disc to the back of the tablet computer without damaging the tablet. 
     Attachment of the holder to the computer tablet may alternatively be accomplished in many other ways.  FIGS. 9 and 10 , for example, show a back cover  35  with an aperture  36  through which the holder  1  is removably inserted. In this embodiment, when the holder  1  is not in place, the cover  35  could conveniently remain on the tablet without distorting the tablet&#39;s thin profile. It may be noted that in the illustration, the top of the holder comprises an alternative configuration to the curved top shown in other embodiments. 
     A different embodiment of the invention is shown in  FIGS. 12-17 . In this embodiment, an attachment unit comprising a base with a plurality of vertical tines fits into a cavity in the base of the holder. As seen in  FIG. 12 , holder  1  has a cavity  21  in base  10 . Instead of a magnet, a retainer ring  41  is inserted into the top portion of cavity  21  and affixed. The retainer ring  41  has an angled retainer ledge  42  around its inside surface, with a slight downward angle. Although one embodiment includes an inserted ring  41 , which is convenient for placement in units configured to accommodate a holder magnet  25 , as shown in  FIG. 7 , it also may be desirable to fabricate a holder having an angled retainer ledge integral with the unit. 
     As shown in  FIGS. 16 and 17 , attachment unit  50  comprises a base  43  and a plurality of vertical tines  44 . Each tine  44  has an engagement lip  45  at its free end. Engagement lip  45  has a slight upward angle to match the angle of angled retainer ledge  42  on retainer ring  41  in base  10  of the holder. This locks the attachment unit  50  and the holder  1  together, as illustrated in  FIG. 15 . The tines  44  may be made of plastic or another material that affords slight flexure when force is applied at the tip so that they slide past the angled retainer ledge  42  when pressed into the cavity  21  of the holder and can be pulled away from the retainer ring  41  with the application of moderate force. Preferably the flexure of the tines  44  will also allow a user to rotate the orientation of the holder when the engagement lips  45  and the angled retainer ledge  42  are engaged. 
     Attachment unit  50  may be affixed to the back of the tablet device, using glue or other suitable adhesive, and holder  1  may then be attached and removed as needed. Alternatively, attachment unit  50  may be affixed to the tablet in a manner similar to that shown in  FIGS. 9 and 10 , wherein the base  43  is held in place by a tablet cover that has an aperture  36  larger than the diameter of the tines  44  but smaller than the diameter of the base  43 . An attachment unit designed for use with a tablet cover will be dimensioned so that the length of the tines protruding past the tablet cover is long enough to permit engagement with the retainer ring in the holder. 
     The holder device may be fabricated or constructed of a variety of materials, with polymers or plastics particularly suitable. In an embodiment, a hard plastic molded endoskeleton  31  is enveloped by a softer plastic or polymer overmold  32 . The overmold skin, which in one embodiment is about 0.02 in thick, can be clear, revealing the endoskeleton, or any of a variety of colors. The skin may be seamless and sanitizable, for use in clean environments such as medical operating rooms. In some embodiments, the endoskeleton  31  may be configured to hold a dime-sized disc  33  that may incorporate a printed, engraved or embossed design or logo. See  FIG. 11 . 
     The foregoing description has been presented and is intended for the purposes of illustration and description. It is not intended to be exhaustive nor limit the invention to the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application and to enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out the invention.