Abstract:
A stylus for a handheld computing device has a clip with detents and spaced apart ribs for securing the stylus in a stylus slot of the handheld device. The clip has grooves on the outward-facing surface, making the clip easier to grasp in order to remove the stylus from the stylus port. The stylus can include a replaceable, retractable ball point pen tip extending from the end of the stylus opposite the stylus tip.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of writing instruments and in particular to a new and useful stylus with a retractable pen adapted for storage in a side slot of many types of personal digital assistants. 
     Personal digital assistants (PDAs) or handheld computing devices are becoming more and more popular. Typically, these devices are too small to incorporate a keyboard, and so a non-marking stylus is required to enter data and make selections on a touch-sensitive screen of the devices. Examples of these devices include the M100 and M505 sold by Palm, Inc. of Santa Clara, Calif., JORNADA sold by Hewlett-Packard of Palo Alto, Calif. and CASSIOPEIA sold by Casio, among others. 
     PDAs and handheld computing devices commonly have a slot, or stylus port, in the side of the device adapted to hold a plain plastic stylus (sometimes referred to as a “nail” because of its appearance) These stylii are simple elongated rods having a stylus tip at one end and sized to be inserted and retrieved from the stylus port in the PDA casing side. The stylii provided with most PDAs sold at retail are simply non-marking stylii of the “nail” type. 
     PDAs have the limitation that most printers are not sized to be portable, and so data that is stored on a PDA can only be converted to a hard copy by either manually writing down the information displayed on the PDA screen, or connecting to a laptop or desktop computer with a printer and transferring data for printing. For the simple job of writing down a telephone number or short address, the latter option is very impractical. As a result, it is often necessary for PDA users to carry both pens and stylii in order to use the PDA without damaging the screen and still be able to create pen on paper notes. 
     Stylii combined with pens are generally known, such as the one taught by U.S. Pat. No. 5,913,629, in which a stylus tip is provided on one side of the pen point for a retractable pen tip. The pen tip extends past the stylus tip when it is in a use position. 
     U.S. Pat. No. 5,564,850 discloses a combined pen and stylus writing instrument having the pen tip at one end of the instrument and the stylus tip at the other. 
     Neither of these pens is disclosed as being particularly suited to be held in the side slot of a PDA. 
     Although many handheld computing devices have stylus ports for holding stylii, there are few mechanisms for keeping a stylus in place in the slot. Generally, stylii are simply held by a frictional fit between components. At least one known stylus, for example, has small hemispherical projections on the sides of the stylus body for mating with corresponding recesses inside a complimentary- stylus port. However, this feature can result in some difficulty experienced when removing the stylus from the handheld computing device or PDA. Alternatively, in some cases, it is possible that a stylus inserted into a PDA casing stylus port will fall out when the device is turned with the stylus port opening facing downward. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a combined stylus and pen for easy use and storage with handheld computing devices. 
     It is a further object of the invention to provide a stylus which can be removably held securely in a slot of a handheld computing device provided for receiving a stylus. 
     Accordingly, a combined pen and stylus writing instrument is provided having a retractable refillable pen tip extending from a pen point at one end of an elongated cylindrical housing and a non-marking stylus mounted on the other end of the housing. The stylus is mounted to the end of a pen activation cap at the end of the housing opposite the pen point. 
     A clip extends from one side of the pen activation cap below the stylus. A pair of detents are provided, one on each side of the clip, for engaging extensions from the edges of a stylus port on a PDA or handheld computing device. The outer surface of the clip has a series of grooves for making the stylus clip easier to grip and exert sufficient force on the stylus to remove it from a stylus port. A pair of ribs are located 180° apart, arranged symmetric around the clip. The ribs help retain the stylus in the stylus port by increasing frictional fit. 
     The various features of novelty which characterize the invention are pointed out with. particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is an exploded perspective view of a combined stylus and pen of the invention; 
     FIG. 2 is a top plan view of the stylus end of the stylus and pen of FIG. 1; 
     FIG. 3 is a side elevation view of the stylus end of FIG. 2; and 
     FIG. 4 is a side elevation view of a stylus of the invention being inserted in the stylus port of a handheld computing device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, in which like reference numerals are used to refer to the same or similar elements, FIG. 1 shows a combined pen and stylus writing instrument  10  for a handheld device, such as a PDA or handheld computer, having a stylus port. 
     The writing instrument  10  is preferably between about 3 and 5 inches long for use with most commercially available handheld computing devices having stylus ports, but can be varied to fit a particular device. The writing instrument  10  is most preferably about 4 inches long. The diameter of the writing instrument housing  50  is also selected to fit the stylus ports of existing handheld computing devices, and can be sized as necessary. The diameter is preferably between {fraction (3/32)} inch and 0.25 inch, and most preferably about ⅛ inch. 
     The writing instrument  10  has a removable pen point  40  at one end of elongated cylindrical housing  50 . A pen tip  30  of a refill cartridge  35  is extended and retracted through the pen point  40  for use and storage, respectively. A non-marking stylus point  20  is provided at the other end of the writing instrument  10 . 
     A pen activation cap  55  is located at the opposite end of the housing  50  from the pen point  40 . The pen activation cap  55  is rotatably secured to the housing  50  for extending and retracting the pen tip  30  from within the housing  50  by activating a propelling and retracting mechanism inside the housing. The propelling and retracting mechanism can be any known mechanism that can be scaled to fit the housing  50  and, activated by relative rotation of components. The non-marking stylus point  20  is mounted. on the free end of the pen activation cap  55 . 
     As seen in FIGS. 1-3, a clip  60  is formed on one side of the pen activation cap  55  and extends longitudinally from below the stylus point  20  over a portion of the upper end of housing  50 . The clip  60  may move freely over the surface of housing  50  when the pen activation cap  55  is rotated. The clip  60  may contact the surface of the housing  50 , but it is preferably spaced above the surface of the housing  50  to increase the freedom of rotational movement and provide a small space for clipping the writing instrument  10  over a thin object, such as a shirt pocket or a small stack of paper. 
     The clip  60  preferably has a generally oval or elliptical shape, with convex side surfaces and rounded top and bottom points. The clip  60  is preferably formed integral with the pen activation cap  55 , but they can be separate components secured together. 
     The clip  60  includes horizontal grooves  70  on the outward-facing surface of the clip  60 . Preferably there are three grooves  70 , but there can be as few as one groove  70 . The upper limit for the number of grooves  70  is limited simply by the size of the clip  60 , since there needs to be enough space to form both grooves and ridges in the clip outer surface. When the clip  60  is about 0.5 inch in length, the number of grooves  70  should not exceed about 7. Clearly, if the clip  60  is made longer, then additional grooves  70  can be added. 
     The clip  60  further includes a pair of detents  65 , one in each side surface of the clip  60 . The detents  65  are preferably located on the clip  60  at a point just above the upper end of the housing  50  where the pen activation cap  55  is connected. 
     FIG. 4 illustrates how the detents  65  can be used to interact with projections or barbs  120  on the edges of a stylus port  110  of a handheld computing device  100 . The writing instrument  10  is slid into stylus port  110  in the direction of arrow A until detents  65  (not visible in FIG. 4) are even with the projections  120 , and the projections  120  fit into the detents  65 . The projections  120  and detents  65  work to hold the writing instrument  10  in place within the stylus port  110 . Grooves  70  provide a gripping surface for assisting in the removal of the writing instrument  10  from the stylus port  110 . 
     Another feature of the writing instrument  10  which works to hold it in a stylus port  110  is ribs  80 . A pair of ribs  80  are positioned 180° apart on each side of the pen activation cap  55 , spaced evenly from the clip  60 . Ribs  80  have a generally triangular shape, as they continue the contour of the housing  50 , as the pen activation cap  55  tapers toward the end of the stylus tip  20 . 
     The ribs  80  provide the same width to the writing instrument  10  at the upper end as along the length of housing  50 . Alternatively, the ends  82  of the ribs may extend slightly wider than the housing  50 . Thus, when the writing instrument  10  is inserted in a correspondingly sized stylus port  110 , the ribs continue to contact the sides of the stylus port  110  and provide a frictional fit in the port  110 . The strength of the frictional fit is increased when the distance between the ends  82  is made greater than the width of housing  50 . 
     The ribs  80 , grooves  70  and clip  60  each additionally serve to provide a positive grip for rotating the pen activation cap  55  to propel and retract the refill cartridge  35  between the use and storage positions in the writing instrument  10 . 
     Referring again to FIG. 1, as seen, the pen point  40  can be secured to the housing  50  by a threaded connection  45 . The refill cartridge  35  can be replaced by removing the pen point  40 , and then removing a spent refill cartridge  35 , inserting a new cartridge  35  in its place and reattaching the pen point  40 . 
     In an alternative embodiment, the writing instrument  10  does not include the retractable pen, but the features of the clip  60  adjacent the stylus tip  20  and ribs  80  are still present. 
     In a further alternative, the refill cartridge  35  may be for any type of pen or pencil which can be extended through the pen point  40  by a twisting activation mechanism activated, by the pen activation cap  55 . Thus, the refill cartridge  55  can be a roller ball, ball point pen, marker or pencil lead cartridge, among others. 
     Although the writing instrument  10  of the invention has been disclosed for use with handheld computing devices, it should be understood that the invention is adaptable for use with other devices having similar stylus ports. 
     While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.