Abstract:
Disclosed is a telescoping writing implement that retracts the writing point when in the collapsed position. Importantly, it is simple in design, uses a minimized number of parts, and, uses no metal coil spring. In its most general form, an external pen body is mechanically connected to a writing cartridge such as ballpoint pen refill or touch screen stylus through at least one aperture in a guide tube. Movement of the external pen body downward draws the writing cartridge down inside the guide tube until the writing end of the writing cartridge is exposed and the connecting means such as a clip, screw or pin contacts the lower edge of the aperture or apertures. When the outer pen body is moved upward, it draws the writing cartridge with it inside the guide tube until the writing end is protected inside the guide tube. The limits of travel are governed by the dimensions of the aperture or apertures when the connecting means contacts the edge of the aperture or apertures. Additional elements may include an upper pen body, a pocket retainer clip and internal position detents. Applications include ball point pens, felt tip pens, and computer input styluses.

Description:
1. PRIORITY CLAIM 
       [0001]    This application is a continuation of, claims priority to and the benefit U.S. patent application Ser. No. 13/790,328 filed Mar. 8, 2013. 
     
    
     2. FIELD OF THE INVENTION 
       [0002]    The present invention relates to writing implements, and more specifically to retracting, telescoping ball point pens and other writing apparatuses. 
       3. BACKGROUND 
       [0003]    The use of retractable writing implements such as pens, mechanical pencils and the like is well known and widely used. One beneficial form of retractable writing implement is the telescoping pen which has the advantage of reducing the length of the pen when not being used, and then easily extending the length while simultaneously exposing the writing point for use. For example, U.S. Pat. No. 6,474,889 issued to Kato (Nov. 5, 1982) discloses a telescoping pen employing, among a large number of components, a coil spring. Similarly, U.S. Pat. No. 6,273,627 issued to Muttersinker et al. (Aug. 14, 2001) discloses an expandable pen which extends the writing tip when the pen body is extended. However, the device also requires a coil spring and a large number of other mechanical parts, increasing the cost of manufacture, and reducing lifespan and reliability. 
         [0004]    A published U.S. Patent application (no. 2011/0129285 by Liu et al.) discloses a retractable pen that simultaneously telescopes in length and extends or retracts the writing point, but this invention also employs a spring and has a large number of parts. The cost of manufacturing pens is highly dependent on the number of components and complexity. Moreover, the use of a coil spring not only adds cost but is subject to rusting and corrosion, shortening the life and reducing reliability of the writing device. 
         [0005]    U.S. Pat. No. 4,266,881 issued to Rubens May 12, 1981 attempts to address the high cost and lower reliability of using a spring in a writing implement, but does not disclose a telescoping device, merely a retracting pen having more than one ink cartridge. No one has previously disclosed a telescoping writing implement that extends and contracts while simultaneously exposing and retracting the writing point, without the use of a spring mechanism. 
         [0006]    U.S. Pat. No. 2,518,128 issued to Dufilho (Oct. 14, 1927) discloses a spring-less telescoping pen or pencil having gradations and at least one non-round side, but it does not provide for retracting the writing point inside a protective body. 
         [0007]    U.S. Pat. No. 2,571,830 issued to Buell (Jan. 2, 1948) discloses a telescoping mechanical pencil in which relative movement of two pencil bodies advances the writing lead. However, the telescoping mechanism does not shorten the overall length, does not move the writing tip back into the pencil body and, further, requires a spring. 
         [0008]    U.S. Pat. No. 8,087,841 issued to Liu Jan. 3, 2012) discloses a retractable pen with an extending pen body. However, this invention requires a large number of individual parts (18 individual parts are disclosed), including a coil spring. The mechanism and its assembly are necessarily complex, increasing the cost of manufacture and raising the number of potential points of failure. 
         [0009]    There is also a need to reduce the diameter of pens to allow them to fit certain applications such as inserting into writing tablet bindings, and to make them more convenient for certain users. 
         [0010]    It is therefore an object of this invention to provide a telescoping pen that conveniently extends its length while simultaneously exposing the writing end, and reducing its length while protectively storing its writing end. 
         [0011]    It is a further object of the present invention to provide a telescoping pen apparatus that does not require a coil spring. 
         [0012]    It is a further object of the present invention to provide a telescoping pen with a minimum number of component parts, reducing cost of manufacture and increasing lifetime reliability. 
         [0013]    It is a further object of the present invention to reduce the diameter of the pen body by eliminating internal components that require excessive lateral space. 
       SUMMARY 
       [0014]    To fulfill the above objects, we hereby disclose a novel telescoping writing device that exposes the writing point while simultaneously extending the length of the device, and stowing the writing point while simultaneously contracting the length of the device. This is accomplished by mechanically connecting the outer body with the inner writing body through an aperture in a guide means which is slidably fit inside the outer body. Moving the outer body down moves the inner writing body down in relation to the guide means, pushing it out of a stowage tube. A minimized number of individual parts are used, construction is simple and no coil spring is employed, resulting is a cost savings, a higher degree of reliability and minimal pen diameter. 
       DEFINITIONS 
       [0015]    To avoid confusion and ambiguity, and to aid in defining the scope of the invention claimed, as used herein, the following words will be given the construction denoted: 
         [0016]    “Distal End” shall mean the end of the writing implement opposite the Writing End. 
         [0017]    “Downward” shall mean in the direction toward the writing end. 
         [0018]    “Upward” shall mean toward the Distal End of the writing implement. 
         [0019]    “Writing Cartridge” shall mean any tubular writing, stylus or embossing component such as ball point pen refill, writing lead, felt-tip pen insert or touch screen stylus. 
         [0020]    “Writing End” shall mean the end of the writing implement used for writing, drawing, embossing, or touching a surface such as a touch-sensitive screen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective drawing with cutaway detail of a ball point pen embodiment of the present invention. 
           [0022]      FIG. 2  is an exploded view of a ball point pen embodiment of the present invention made with the minimized number of component parts. 
           [0023]      FIG. 3  is an exploded view of a ball point pen embodiment of the present invention including an upper pen body. 
           [0024]      FIG. 4 a    is a perspective view with cutaway detail of the ball point pen embodiment of the present invention in the extended position. 
           [0025]      FIG. 4 b    is a perspective view of the ball point pen embodiment of the present invention in the contracted position. 
           [0026]      FIG. 5 a    is a perspective view with cutaway detail of an alternative embodiment of the present invention utilizing a metal exterior pen housing with an integral spring clip. 
           [0027]      FIG. 5 b    is a perspective view with cutaway detail of an alternative embodiment utilizing a plastic exterior pen housing having an integral plastic spring clip. 
           [0028]      FIG. 6 a    is a perspective view with cutaway detail of an alternative embodiment of the present invention using a spring clip fitted to the ink refill. 
           [0029]      FIG. 6 b    is an exploded view of an alternative embodiment of the present invention using a spring clip fitted to the ink refill. 
           [0030]      FIG. 7  is an exploded a view of an embodiment of an optional upper portion of the present invention having position selection detents. 
           [0031]      FIG. 8  is a perspective view of a computer input stylus embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    The present invention utilizes a minimized number of parts to manufacture a telescoping writing implement, typically a ball point pen. With this device we have eliminated the need for a coil spring and have enabled the manufacture of the telescoping pen with as few as 4 to 6 parts. The low part count significantly reduces manufacturing costs and improves reliability. 
         [0033]      FIG. 1  depicts the ballpoint pen  110  embodiment of the present invention. Here, a writing cartridge  114  is slidably inserted into a guide tube  118 . The guide tube has an outwardly extending flange  120  formed at its distal end. A groove (not visible in this view) is formed peripherally around the circumference of the writing cartridge. (See  FIG. 3  for additional detail). An upper pen body  124  is slidably fit and inserted over the guide tube  118  from the writing end  126 . By virtue of a counterbore  128  formed inside the upper pen body, the upper pen body is stopped at the extended position as shown. At least one aperture is cut through the guide tube [not visible in this view]. A lower external pen body  130  is slidably fit over the guide tube  118 . A slot opening  134  in the lower pen body  130  aligns with the aperture or apertures in the guide tube and the circumferential groove in the writing cartridge  114  allowing a retaining clip  138  to be inserted and snap around the writing cartridge  114  through the aperture or apertures, mechanically connecting it to the lower external pen body  130 . In this example, each tang of the U-shaped retaining clip  138  is inserted through each opposing aperture and engages the circumferential groove of the writing cartridge  114 . The dimensions of the opposing apertures determine the limit of movement of the writing cartridge  114  when moving the pen body in relation to the guide tube. The length of the opposing apertures should allow the writing point to extend an adequate distance past the lower opening of the pen body to permit convenient writing, and retract an adequate distance into the guide tube to protect it. 
         [0034]    The U-shaped retaining clip  138 , therefore, is a connecting means securing the lower pen body  130  to the writing cartridge  114 . 
         [0035]    Movement of the lower external pen body  130  downward moves the writing cartridge  114  writing end  126  downward, exposing the writing end  126  out of the guide tube  118 . Movement of the lower external pen body  130  upward (toward the distal end  122 ), retracts the writing end  126  of the writing cartridge  114  into the guide tube  118 , while simultaneously shortening the overall length of the ballpoint pen. Additionally, when the external upper pen body  124  is moved toward the writing end  126 , the overall length the ball point pen is additionally shortened. Adequate friction should be provided between the writing cartridge  114  and the guide tube  118  and/or between the lower external pen body  130  and the guide tube  118  to hold the pen in the open or closed positions for use or storage respectively, but allow convenient relative movement of the component parts. This may be accomplished by a number of methods well known to one of ordinary skill in the art, such as crimping the guide tube  118  or slotting the writing end of the guide tube  118  so that swaging the writing end of the external pen body  130  would compress the slotted end of the guide tube  118  against the writing cartridge  114 . An end cap  129  is inserted in the distal end of the upper pen body  124 . The present invention can be manufactured without the upper pen body  124 , using the guide tube  118  as the functional upper portion of the pen (see  FIG. 2 ). However, it is considered beneficial to use an upper pen body  124  as shown to make it easier and more comfortable to hold the pen  110  when using it. It is further beneficial to incorporate a pocket retaining clip  132  as part of the upper pen body  124 . 
         [0036]      FIG. 2  is an exploded view of a ball point pen representing a simplified embodiment of the present invention made with the minimized number of component parts. A writing cartridge  214  is slidably inserted into a guide tube  218 . The writing cartridge has a groove  219  formed circumferentially around its perimeter. The guide tube has opposing apertures  221  in its periphery. An external pen body  222  having a slot opening  223  in its perimeter is inserted over the guide tube  221 . The slot opening  223  and the opposing apertures  221  are aligned with the circumferential groove  219  and a U-shaped retaining clip  224  is inserted through the slot opening  223  and the opposing apertures  221 , engaging the writing cartridge  214  in the circumferential groove  219 . In this example, each tang of the U-shaped clip  224  is inserted into each opposing aperture  221 . As in  FIG. 1 , movement of the pen body  222  downward moves the retaining clip  224 , and thus the writing cartridge  219  downward in relation to the guide tube  218 . As described in  FIG. 1 , but more clearly visible in  FIG. 2 , the dimensions of the opposing apertures  221  determine the limit of movement of the writing cartridge  218  when moving the pen body in relation to the guide tube. The length of the opposing apertures  221  should allow the writing point  227  to extend an adequate distance past the lower opening of the pen body to permit convenient writing, and retract an adequate distance into the guide tube  218  to protect it. It should be noted that the present embodiment or the others disclosed here may be manufactured using a single aperture  221  in the guide tube and a pin, single-prong clip or other interconnecting element in place of the U-shaped clip  224 , engaging the writing cartridge  218  through the aperture. Such variations would be obvious to one of ordinary skill in the art and the disclosure of the U-shaped clip  224  is not intended to limit the scope of the means of connecting the external pen body  222  to the writing cartridge  214  which can be accomplished with a wide variety of alternative structures well known in the industry. 
         [0037]      FIG. 3  is an exploded view representing a ball point pen embodiment of the present invention including an upper pen body. In this example, identical to  FIG. 1 , we more fully illustrate the assembly of this embodiment. A writing cartridge  314  is slidably inserted into a guide tube  318 . The guide tube  318  has a radially-formed outwardly extending flange  319  at its distal end. A groove  320  is formed circumferentially around the writing cartridge  314 . An upper pen body  324  is slidably fit and inserted over the guide tube  318  from the guide tube&#39;s writing end  326 . By virtue of a counterbore  328  formed inside the upper external pen body  314 , the upper pen body  324  is stopped at the extended position when the guide tube&#39;s outwardly extending flange  319  engages the upper pen body&#39;s  324  counterbore  328 . Opposing apertures  329  are cut through the guide tube  318 . A lower external pen body  330  is slidably fit over the guide tube  318 . A slot opening  334  in the lower pen body  330  aligns with the opposing apertures in the guide tube and the circumferential groove  320  in the writing cartridge  314  allowing a U-shaped retaining clip  338  to be inserted through the slot opening  334  and each tang of the U-shaped clip  318  is inserted through each opposing aperture  329 , snapping around and engaging the writing cartridge  314  within the circumferential groove  320 , mechanically connecting it to the lower external pen body  330 . Movement of the lower external pen body  330  downward moves the writing cartridge  314  writing end  327  downward, exposing it out of the guide tube  318 . Movement of the lower external pen body  330  upward (toward the distal end  322 ), retracts the writing end  327  of the writing cartridge  314  into the guide tube  318 , while simultaneously shortening the overall length of the ballpoint pen assembly. Additionally, when the external upper pen body  324  is moved toward the writing end  326 , the overall length the ball point pen is additionally shortened. 
         [0038]    The dimensions of the opposing apertures  329  determine the limit of movement of the writing cartridge  314  when moving the pen body  330  in relation to the guide tube  318 . Ideally the length of the opposing apertures  329  should allow the writing point  327  to extend an adequate distance past the lower opening of the pen body  330  to permit convenient writing, and retract an adequate distance into the guide tube  318  to protect it. Adequate friction is provided between the pen body  330  and the guide tube  318  and/or between the writing cartridge  314  and the guide tube  318  to hold the pen in the extended position or contracted position for writing or storage receptively, but allow convenient relative movement of the component parts. Methods and structures of providing friction may include crimping the guide tube  318  so as to cause it to rub against the writing cartridge  314 , sizing the bore of the lower external pen body  330  to cause it to friction-fit with the guide tube  318  or inserting a spring element between the lower external pen body  330  and the guide tube  318 . Such means of providing adequate friction, including a wide variety of alternative means, would be obvious to one of ordinary skill in the art and are not intended to limit the scope of the patent. 
         [0039]    An end cap  332  is inserted in the distal end of the upper pen body  324 . It should be noted that the present embodiment or the others disclosed here may be manufactured using a single aperture  329  in the guide tube and a pin, screw, single-prong clip or other interconnecting element in place of the U-shaped clip, engaging the writing cartridge  314  through the aperture. Such variations would be obvious to one of ordinary skill in the art. 
         [0040]      FIG. 4 a    is a view of the ball point pen  400   a  embodiment of the present invention in the extended position. The writing end of the writing cartridge  414   a  is exposed, extended outside the guide tube  418   a  and lower external pen body  430   a . The upper external pen body  432   a  is extended to the stop formed by the outwardly extending flange  419   a  formed in the distal end of the writing cartridge coming into contact with the counterbore  428   a  of the upper external pen body  432   a.    
         [0041]      FIG. 4 b    is a view of the ball point pen  400   b  embodiment of the present invention in the contracted position. The writing end of the writing cartridge  414   b  is contracted inside the guide tube  418   b  and lower external pen body  430   b . The upper external pen body  432   b  is contracted downward along the guide tube  418   b  shortening the overall length of the pen assembly  400   b.    
         [0042]      FIG. 5 a    is a perspective view with cutaway detail of an embodiment of the present invention utilizing a metal lower external pen body  530   a . In contrast with the embodiment described in the above figures, a separate clip to engage the writing cartridge  514   a  is not used. Instead, a spring clip  524   a  is formed as part of the metal lower pen body  530   a  and becomes the connecting means to connect the external pen body  530   a  with the writing cartridge  514   a . As in the previous examples, the writing cartridge  514   a  incorporates a circumferential groove  519   a  into which the spring clip  524   a  engages. When the lower external pen body  530   a  is pulled down toward the writing end, the spring clip  524   a  draws the pen cartridge  514   a  down the length of the aperture  521   a  formed in the guide tube  518   a , extending it out of the guide tube. The spring clip  524   a  may also be made as a separate part and fixed to the lower pen body  530   a  by means well-known in the art such as welding, friction insertion or gluing. In all other respects, this embodiment is similar to the previously described embodiments. 
         [0043]      FIG. 5 b    is a perspective view with cutaway detail of an alternative embodiment utilizing a plastic exterior pen housing with an integral plastic spring clip. As in  FIG. 5 a   , a separate clip is not needed as a connecting means to mechanically connect the external pen body  530   b  to the writing cartridge  514   b . Instead, a spring clip  524   b  is formed as part of the plastic external pen body  530   b . The spring clip  524   b  incorporates a protrusion  525   b  which extends through an aperture  521   b  in the guide tube  518   b  and engages the circumferential groove  519   b  in the writing cartridge  514   b . Movement of the external pen body  530   b  in a downward direction will move the writing cartridge  514   b  downward until the spring clip  524   b  comes in contact with the lower edge of the aperture  521   b , causing the writing tip of the writing cartridge  514   b  to protrude out of the guide tube  518   b.    
         [0044]    Advantageously, this embodiment uses a reduced number of parts and can be made with low-cost manufacturing methods. Additionally, since no spring steel is utilized, corrosion and rusting is eliminated. Both embodiments illustrated in  FIGS. 5 a  and 5 b    will also benefit from the addition of an upper pen body such as illustrated in  FIG. 3 . 
         [0045]      FIG. 6 a    is a perspective view with cutaway detail of an alternative embodiment of the present invention using a spring clip  610  assembly press-fit or otherwise attached to the writing cartridge  614 . In this embodiment of the present invention the spring clip  610  comprises a tubular portion  616  with a protruding spring arm  618 . The assembly comprising the spring clip  610  attached to the writing cartridge  614  is inserted into a guide tube  620  containing an aperture (not visible in this view) through which the protruding spring arm  618  protrudes. The guide tube  620  containing the writing cartridge  614  with the spring clip  610  attached is inserted into an external pen body  624 . The external pen body  624  contains an indentation  626  in its inner wall configured to accept the end of the protruding spring arm  618 . When the external pen body  624  is drawn downward by the user its movement is stopped by the lower edge of the aperture  622  formed in the guide tube  620  and the movement extends the writing end  628  of the writing cartridge  614  out of the guide tube  620 . The guide tube  620  and external pen body  624  can be made of a variety of materials including plastic or metal. The spring clip may also be made of plastic but will be more resilient if made of metal. When the user moves the pen body  624  upward (toward the distal end  625 ), the writing cartridge  614 , by virtue of its connection to the pen body  624  via the spring clip  610 , is drawn up into the guide tube  620 . The length of the movement up into the guide tube  620  is determined by the dimensions of the aperture  622  as the movement is stopped by the upper edge of the aperture  622 . A protruding spring clip  618  may be attached to the writing cartridge  614  in a variety of ways that will be well-known to one skilled in the art such as press-fitting, spot welding or gluing. Moreover, the spring clip may be manufactured using either metal or plastic. An upper pen body is preferably added to this embodiment as more fully described in  FIGS. 1, 3, 4   a ,  4   b , and  7 , any of which configuration is adaptable to this embodiment. 
         [0046]      FIG. 6 b    is an exploded view of the embodiment described by  FIG. 6 a   . It may be seen spring clip assembly  610  is affixed to the narrower lower portion of the writing cartridge  614 . The combined writing cartridge  614  and spring clip assembly  610  is inserted into the distal end of the guide tube  620  until the spring clip arm  618  snaps into the aperture  622  of the guide tube  620 . 
         [0047]      FIG. 7  is an exploded view of a pen embodiment of the present invention having an optional upper portion with position selection detents. In this variation, a writing cartridge  714  is slidably inserted into a guide tube  718 . As in  FIG. 1 , the guide tube has an outwardly extending flange  720  formed at its distal end, but the flange  720  and distal end are slit longitudinally allowing the distal end to resiliently compress. 
         [0048]    A groove  719  is formed circumferentially around the periphery of the writing cartridge. An upper pen body  724  is slidably fit and inserted over the guide tube  718  from the writing end  726 . The guide tube  718  is longer than the writing cartridge  714  to allow contraction of the pen. Invaginated detents  728  and  729  are formed inside the upper pen body. As the guide tube  718  moves within the upper pen body  724 , the outwardly extending compressible split flange  720  indexes into one of the detents  728  or  729 . A pair of opposing apertures  721  are formed through the guide tube  718 . A lower external pen body  730  is slidably fit over the guide tube  718 . A slot opening  734  in the lower pen body  730  aligns with the opposing apertures  721  in the guide tube and the circumferential groove  719  in the writing cartridge  714  allowing each of the tangs of the U-shaped retaining clip  738  to be inserted through the slot opening  734  and each of the opposing apertures  721 , and snap around and engage with the writing cartridge  714  within the circumferential groove  719 , mechanically connecting it to the lower external pen body  730 . Movement of the lower external pen body  730  downward moves the writing cartridge  714  writing end  727  downward, exposing it out of the guide tube  718 . The compressible flange  720  snaps into the lower detent  729  holding the apparatus in the open position for use. Movement of the lower external pen body  730  upward (toward the distal end  722 ), retracts the writing end  727  of the writing cartridge  714  into the guide tube  718 , while simultaneously shortening the overall length of the ballpoint pen. The compressible split flange  720  snaps into the upper detent  728  holding the apparatus in the retracted position for storage. Additionally, when the external upper pen body  724  is moved toward the writing end  727 , the overall length of the ball point pen is further shortened. An optional end cap  726  is inserted in the distal end  722  of the upper pen body  724  to exclude dirt. 
         [0049]      FIG. 8  is a view of an embodiment of the present invention as a computer input stylus. It may be seen that any of the embodiments shown herein may be adapted to a computer stylus or similar device with very little departure from the teachings herein.  FIG. 8  is one such adaptation and is not intended to limit such adaptations to this embodiment or to dedicate any obvious variations to the public. 
         [0050]    Specifically,  FIG. 8  depicts a computer interface (touch screen) stylus  810  embodiment of the present invention. A stylus insert (the analog of a writing cartridge disclosed herein) comprising a stylus shaft  814  and a stylus tip  815 . The stylus shaft  814  is slidably inserted into a guide tube  818 . The guide tube has an outwardly extending stop flange  820  at its distal end. A groove (not visible in this view) is formed circumferentially around the stylus shaft along its length. An upper stylus body  824  is slidably fit and inserted over the guide tube  818  from the writing end  815 . By virtue of a counterbore  828  formed inside the upper stylus body, the upper stylus body is stopped at the extended position as shown. As in the prior embodiments, opposing apertures (not visible in this view) are cut through the guide tube  818 . A lower external stylus body  830  is slidably fit over the guide tube  818 . A slot opening  834  in the lower stylus body  830  aligns with the opposing apertures in the guide tube  818  and the circumferential groove in the stylus shaft  814  allowing each of the  2  tangs of a U-shaped retaining clip  838  to be inserted through each of the opposing apertures in the guide tube  818  and snap around a circumferential groove in the stylus shaft  814 , mechanically engaging the lower external stylus body  830 . Movement of the lower external stylus body  830  downward moves the stylus writing end  815  downward, exposing it out of the guide tube  818  and lower external stylus body  830 . Movement of the lower external stylus body  830  upward (toward the distal end  822 ), retracts the writing end  815  of the stylus insert  814  into the guide tube  818  and lower external stylus body  830 , while simultaneously shortening the overall length of the stylus  819 . The amount of movement of the stylus shaft  814  is limited by the dimensions of the opposing apertures. Additionally, when the external upper stylus body  824  is moved toward the writing end  826 , the overall length the stylus is additionally shortened. An end cap  828  is inserted in the distal end of the upper stylus body  824 . The present invention can be manufactured without the upper stylus body  824 , using the guide tube  818  as the upper portion of the stylus. However, it is considered beneficial to use an upper stylus body  824  as shown to make it easier and more comfortable to hold the stylus  810 . It can be beneficial to incorporate a pocket retaining clip  832  as part of the upper stylus body  824 . Similarly, a stylus insert may be substituted for the writing cartridge in any of the foregoing embodiments. As discussed above, it should be noted that a single aperture may be used in the side of the guide tube  818  to permit a single-prong clip, pin or similar device to engage the stylus. For example, a screw or pin may be inserted into the stylus shaft  814  through a hole in the external stylus body  830  and the aperture [not visible] in the stylus shaft  814 . 
         [0051]    The specific implementations disclosed above are by way of example and for enabling persons skilled in the art to implement the invention only. We have made every effort to describe all the embodiments we have foreseen. There may be embodiments that are unforeseeable or which are insubstantially different. We have further made every effort to describe the invention, including the best mode of practicing it. Any omission of any variation of the invention disclosed is not intended to dedicate such variation to the public, and all unforeseen or insubstantial variations are intended to be covered by the claims appended hereto. Accordingly, the invention is not to be limited except by the appended claims and legal equivalents.