Abstract:
An expandable and contractible stylus for interfacing with a touchscreen of an electronic device. The expandable and contractible feature allows for a stylus that contracts to fit into a stylus holder in a small handheld device and expands to facilitate its removal from a device and to fit more comfortably in a user&#39;s hand. It holds either its expanded or contracted position for any orientation in space. An expandable and contractible stylus can facilitate the user&#39;s experience and thus provide an advantage over the other conventional styluses.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of styluses. Specifically, the present invention relates to a stylus that can be expanded and contracted to fit, respectively, in the hand of a user and in a stylus holder of a small electronic device. 
     2. Related Art 
     A stylus was originally an instrument used by the ancients for writing in clay or wax. Today it is a pointed device that may be used with a touch screen or a digitizing tablet. There are numerous electronic devices that are equipped with touch screens as an interface mechanism. Among these devices are personal computers, both desktop and laptop styles, and handheld devices such as electronic game devices and personal digital assistants (PDAs). 
     There are numerous versions of styluses available today. There are conventional styluses that resemble pens.  FIGS. 1A and 1B  illustrate versions of such styluses,  100   a  and  100   b . Stylus  100   a  may be molded from a plastic type material and configured to fit in the stylus holder of a specific handheld device or it may be milled from any solid material such as wood, metal or a synthetic material lending itself to milling. Stylus  100   b  of  FIG. 1B  may be formed from a metal such as stainless steel, with a molded plastic or nylon tip and cap configured for holding it in the stylus holder of a handheld device. 
     A user of either stylus  100   a  or  100   b  may find the stylus comfortable to use if it is of a sufficient length to fit between the thumb and forefinger and rest against the base of the thumb. However, styluses are typically stored inside the devices with which they are used, thus restricting their length to the length of the device. With the increasingly smaller designs that are evolving in the world of PDAs and other handheld devices, a stylus that would not protrude beyond the end of a small device may be too short to be comfortable in a user&#39;s hand. Also, there is a need for a convenient method of extracting a stylus from a device in which it is stored. 
     One prior art solution is the duplication of a ballpoint pen mechanism. Another prior art solution is a pull-to-detent type of expandable stylus. These solutions have problems such as having too large a diameter to fit into a holder in the device, requiring two hands to extend, and difficulty in removing from the device. The solution using a ballpoint pen mechanism suffers because it does not remain in a contracted position when turned upside down. 
     There are many other conventional versions of styluses available. There are styluses that are molded into pen caps. These styluses have the disadvantage of not fitting into the device for which they are to be used. Therefore, they are susceptible to being misplaced or left behind and, therefore, may not always be readily available when needed. 
     In summary, the evolution of handheld electronic devices is such that they are becoming increasingly smaller and the conventional styluses that fit in a stylus holder in today&#39;s smaller device are too short to fit comfortably in an average user&#39;s hand. A solution to this problem would be advantageous. The present invention, in various embodiments, provides such a solution. 
     SUMMARY OF THE INVENTION 
     The present invention provides an expandable and contractible stylus for interfacing with a touchscreen of an electronic device. The present invention allows for a stylus that contracts to fit into a stylus holder in a small handheld device and expands to facilitate its removal from a device and to fit more comfortably in a user&#39;s hand. It holds either its expanded or contracted position for any orientation in space. An expandable and contractible stylus may facilitate the user&#39;s experience and thus provide an advantage over other conventional styluses. 
     In one embodiment, the present invention is implemented as a stylus comprised of a tube with a tip and tip housing coupled to one end, a slideable shaft within the tube, and a plunger coupled to the shaft. In response to depressing the plunger a first time, the shaft moves from a first position to a second position and remains in the second position for any orientation in space. In response to depressing the plunger a second time, the shaft moves from the second position back to the first position and remains in the first position for any orientation in space. 
     In one embodiment, the stylus further comprises a wedge coupled to the shaft and a rotating indexer coupled to the shaft. The indexer has a raised feature and the indexer is configured to interface with the wedge so as to rotate when the plunger is depressed. The stylus also has a spring contacting the shaft so as to exert a force for locking the raised feature of the indexer and maintaining the shaft in a contracted position. In one embodiment, in the contracted position the stylus fits into a custom stylus holder within a handheld electronic device. 
     In addition to the above, according to one embodiment, the stylus has an outer shaft disposed within the tube and coupled to the shaft. The outer shaft has an inside channel. The raised feature of the indexer is configured to slide into the inside channel when aligned with the channel and acted on by the force from the spring. The force then maintains the shaft in an expanded position. In one embodiment, depressing the plunger while the stylus resides in the holder of a handheld electronic device causes the stylus to expand, thus facilitating removal of the stylus from the device. 
     In one embodiment, the indexer is retained on the shaft by a retaining ring. In another embodiment, the indexer is retained on the shaft by a retaining screw. 
     According to one embodiment, the tip of the stylus is a pen point with ink cartridge that is configured to emerge from the tip housing when the shaft is in the contracted position. 
     These and other objects and advantages of the present invention will become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the various drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a solid stylus in accordance with one embodiment of the prior art. 
         FIG. 1B  illustrates a solid stylus in accordance with one prior art embodiment. 
         FIG. 2A  is an exploded view of an expandable and contractible stylus in accordance with one embodiment of the present invention. 
         FIG. 2B  is a cross-sectional view of an outer shaft of an expandable and contractible stylus according to one embodiment of the present invention. 
         FIG. 3  is an exploded view of an innershaft and plunger of an expandable and contractible stylus according to one embodiment of the present invention. 
         FIG. 4A  illustrates an expandable and contractible stylus in a contracted position, according to one embodiment of the present invention. 
         FIG. 4B  is an illustration of an expandable and contractible stylus in a depressed position, according to one embodiment of the present invention. 
         FIG. 4C  is an illustration of an expandable and contractible stylus in an expanded position, according to one embodiment of the present invention. 
         FIG. 5  illustrates the rotating indexer and wedge of an expandable and contractible stylus, according to one embodiment of the present invention. 
         FIG. 6  is a flow diagram showing a process for expanding and contracting a stylus according to one embodiment of the present invention. 
         FIG. 7  is an exploded view of an expandable and contractible stylus in accordance with one embodiment of the present invention. 
         FIG. 8  is an exploded view of an innershaft and plunger of an expandable and contractible stylus according to one embodiment of the present invention. 
         FIG. 9A  illustrates an expandable and contractible stylus in a depressed position in transit from an expanded to a contracted position, according to one embodiment of the present invention. 
         FIG. 9B  is an illustration of an expandable and contractible stylus in a contracted position, according to one embodiment of the present invention. 
         FIG. 9C  is an illustration of an expandable and contractible stylus in a depressed position in transit from a contracted to an expanded position, according to one embodiment of the present invention. 
         FIG. 9D  illustrates an expandable and contractible stylus in an expanded position, in accordance with one embodiment of the present invention. 
         FIG. 10  is a flow diagram showing a process for expanding and contracting a stylus according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one skilled in the art that the present invention may be practiced without these specific details or with equivalents thereof. In other instances, well-known methods, procedures, and components have not been described in detail as not to unnecessarily obscure aspects of the present invention. 
       FIG. 2A  is an exploded view of expandable and contractible stylus  200  in accordance with one embodiment of the present invention. Plunger (or quill)  210  may be constructed of a molded plastic or a metal or any material that would be appropriate for affixing to a shaft. In one embodiment, plunger  210  is pressed onto boss  215  on the end of inner shaft  240  or, in another embodiment, plunger  210  may be threaded and screwed onto boss  215 . 
     Outer tube  220  is the main body of stylus  200  according to one embodiment. Outer tube  220  can be machined from a metal such as stainless steel, or outer tube  220  can be molded from a synthetic material such as plastic or nylon. It should be appreciated that outer tube  220  can be constructed of any material that lends itself to forming a tube of appropriate size and shape for stylus  200 . Outer tube  220 , according to one embodiment, has a threaded end for receiving removable tip housing  280 . In another embodiment, tip housing  280  is swaged onto outer tube  220 . In one embodiment, tip housing  280  is molded or milled as an integral part of outer tube  220 . 
     Still referring to  FIG. 2A , in the present embodiment, outer shaft  230  is a tube that is disposed within outer tube  220  and fits over an inner shaft  240 . Outer shaft  230  contains channels  232 , as shown in  FIG. 2B . A feature on an indexer (e.g., feature  340  of indexer  245  as shown in  FIG. 3 ) may move inside channels  232  to achieve an expanded position of stylus  200 . The end of outer shaft  230  that houses the opening to the channels  232  has wedge-shaped features  235  that work in concert with a spring  270  and a wedge  250  for locking stylus  200  into a contracted position, according to one embodiment of the present invention. 
     Inner shaft  240  of stylus  200 , shown in detail in  FIG. 3 , houses rotating indexer  245  that, in concert with the outer shaft  230 , spring  270  and wedge  250 , functions to cause stylus  200  to expand and contract, according to one embodiment. 
     In the present embodiment, wedge  250  is a tube that houses spacer  260  and spring  270 , and has wedge-shaped edges that work in concert with the force of spring  270 , outer shaft  230  and rotating indexer  245  to expand and contract stylus  200 , as shown in  FIGS. 4A ,  4 B,  4 C and  5 . 
     Spacer  260  of stylus  200  in  FIG. 2A  functions, in one embodiment, to hold spring  270  away from the wedge end of wedge  250  and to reduce the length of spring  270  needed to exert sufficient force for locking indexer  245  into position. 
     In one embodiment of the present invention, spring  270  exerts a force that locks a protruding feature on indexer  245  into a position with respect to outer shaft  230  so as to maintain stylus  200  in an expanded or contracted position. 
     In the present embodiment, tip housing  280  contains tip  290 , a smooth surface that functions to contact a touchscreen or digitizing tablet of a handheld device for the purpose of interfacing with the device. Tip housing  280  may also house a pen tip with ink cartridge that may allow stylus  200  to alternate between stylus function and pen function. 
       FIG. 2B  is a cross-sectional view of outer shaft  230  of expandable and contractible stylus  200 , according to one embodiment of the present invention. Channels  232  are designed to accept a raised feature on indexer  245 , allowing the feature to slide so as to move innershaft  240  to an expanded position. 
       FIG. 3  is an exploded view  300  of an inner shaft  240  and plunger  210  of expandable and contractible stylus  200 , according to one embodiment of the present invention. Plunger-type quill  210  fits onto boss  215  of inner shaft  240 . Quill  210  is joined to boss  215  by a force fit, according to one embodiment. 
     According to another embodiment, quill  210  and boss are threaded so that quill  210  screws onto boss  215 . 
     Inner shaft  240  has a main body  310  and a lower boss  320  onto which indexer  330  fits in accordance with one embodiment of the present invention. Indexer  330  is held on lower boss  320  by a retaining device  350 . In one embodiment, the retaining device is a retaining ring. In another embodiment, the retaining device is a retaining screw. Indexer  330  rotates freely around lower boss  320  when retaining device  350  is in place. 
     Still referring to  FIG. 3 , indexer  330  has a number of evenly spaced raised features  340  that are designed, according to one embodiment, to slide into channels inside an outer shaft  230  when the indexer  330  is positioned for expanding stylus  200 . Raised features  340  are designed to be captured by a wedge feature  235  of the outer shaft when in a contracted position, according to one embodiment. In one embodiment, raised features  340  are triangular in shape. These features may, however, be of any design that would slide into channels in outer shaft for expanding a stylus and be captured by features in a wedge when the stylus is contracted. 
       FIG. 4A  illustrates an expandable and contractible stylus in a locked, contracted position  400   a , according to one embodiment of the present invention. A portion  410  of inner shaft  240  is seen between quill  210  and outer tube  220  when stylus  200  is in the contracted position. In this contracted position  400   a , stylus  200  is designed to be stowed in a holder portion of a device with which it is to be used. 
       FIG. 4B  is an illustration of an expandable and contractible stylus in a depressed position  400   b , according to one embodiment of the present invention. In this position, a user is pressing on quill  220  and no part of inner shaft  240  is visible at location  420 . Indexer  330  has been rotated to a next position (see  FIG. 5 ) so that, upon releasing, if the stylus had been in a contracted position, it will expand or, having been in an expanded position, it will assume a contracted position. 
       FIG. 4C  is an illustration of an expandable and contractible stylus in an expanded position  400   c , according to one embodiment of the present invention. Note that a portion  430  of the body  310  of inner shaft  240  is visible in expanded position  400   c . In position  400   c  stylus  200  is elongated to fit more comfortably in the hand of a user. In one embodiment, if a user depresses quill  210  while stylus  200  is contracted and residing in a device holder, stylus  200  expands to position  400   c  for easy extraction from the device. 
       FIG. 5  illustrates the operation  500  of the protruding feature  340  of rotating indexer  330  and wedge  250  of expandable and contractible stylus  200 , according to one embodiment of the present invention. Channels  232   a  and  232   b  are rectangular channels that are molded or routed inside of an outer shaft (e.g., outer shaft  230  of  FIG. 2 ) of stylus  200  according to one embodiment. Wedge features  235  are at the lower end of outer shaft  230  in one embodiment of the present invention. Raised features  340  on indexer  245  are shown in positions  340   a ,  340   b ,  340   c ,  340   d  and  340   e  to illustrate the operation of the expandable and contractible functions of stylus  200 , in accordance with one embodiment. 
       FIG. 6  is diagram of a process  600  of expanding and contracting stylus  200  according to one embodiment of the present invention.  FIG. 6  will be discussed in concert with  FIG. 5  and also with reference to  FIGS. 2 and 3  to explain the operation of stylus  200 . 
     In step  610 , the process  600  begins with the indexer and its raised features at position  340   a , at the top of channel  232   a  within outer shaft  230 . Although specific steps are disclosed in process  600 , such steps are exemplary. That is, the present invention may be well suited to performing various other steps or variations of the steps recited in  FIG. 6 . 
     At step  620  of process  600 , according to one embodiment, a user presses down on quill  210  that, in turn, presses down on inner shaft  240  and indexer  245 , causing raised features  340  of indexer  245  to slide down channels  232   a  and  232   b  of outer shaft  230  in the direction shown by arrow  510 . At this point, stylus  200  is in the depressed position as illustrated in  FIG. 4B . 
     At step  630  of  FIG. 6 , according to one embodiment, the raised feature  340  contacts wedge  250  and rotates indexer so that feature  340  resides in position  340   b . Next, as stated in step  640 , the user releases quill  210  and main spring  270  exerts an upward force in the direction of arrow  520 , causing indexer  245  to rotate and capturing feature  340  in position  340   c  in wedge shaped feature  235  at the bottom of outer shaft  230 . At this point stylus  200  is in a contracted position as shown in  FIG. 4A . Stylus  200  may be inverted or held in any orientation in space in this contracted position and quill  210  will remain contracted. 
     At step  650  of process  600 , the user presses down on quill  210  once more and wedge  250  causes indexer  245  to rotate in the direction of arrow  530  so that raised feature  340  assumes position  340   d . At this point, stylus is once again in a depressed position as illustrated by  FIG. 4B . 
     At step  660 , the user releases quill  210  and the pressure from spring  270  causes feature  340  to encounter a wedge-shaped feature  235  at the end of outer shaft  230 , according to one embodiment. Feature  340  moves along the edge of the wedge-shaped feature and, in turn, causes indexer  245  to rotate in the direction of arrow  540 . Raised feature  340  enters channel  232   b , and, with the force of spring  270 , travels to the top of channel  232   b , thus pushing out inner shaft  240  and expanding stylus  200 . 
     Although outer shaft  230  is shown to have two channels,  232   a  and  232   b , it should be understood that there may be two, three, four, or any number of evenly spaced channels to correspond with the number of raised features  340  on indexer  245 . 
       FIG. 7  is an exploded view of an expandable and contractible stylus  700  in accordance with one embodiment of the present invention. Plunger—style quill  210  may be constructed of a molded plastic or a metal or any material that would be appropriate for affixing to a shaft. In one embodiment, plunger  210  is pressed onto boss  215  at the end of inner shaft  720  or, in another embodiment, plunger  210  is threaded and screwed onto boss  215 . 
     Outer tube  220  is the main body of stylus  700  according to one embodiment. In one embodiment, outer tube  220  is machined from a metal such as stainless steel, or, according to another embodiment, outer tube  220  is molded from a synthetic material such as plastic or nylon. It should be appreciated that outer tube  220  may be constructed of any material that lends itself to forming a tube of appropriate size and shape for stylus  700 . Outer tube  220 , according to one embodiment, has a threaded end for receiving removable tip housing  280 . In another embodiment, tip housing  280  is swaged onto outer tube  220 . In one embodiment, tip housing  280  is molded or milled as an integral part of outer tube  220 . 
     Still referring to  FIG. 7 , outer shaft  710  is a tube that fits over an inner shaft and contains channels  715  that a raised feature on an indexer  740  follows to achieve an expanded position of stylus  700 . The end of outer shaft  710  that houses the opening to channels  715  has wedge-shaped features  235  between the channels that work in concert with a spring  270  and a wedge  750  for locking stylus  700  into a contracted position, according to one embodiment of the present invention. 
     Inner shaft  720  of stylus  700 , shown in detail in  FIG. 8 , houses rotating indexer  740  that, in concert with the outer shaft  710 , spring  270  and wedge  750 , functions to cause stylus  700  to expand and contract, according to one embodiment. 
     Wedge  750  is a feature that rotates on the inner shaft assembly  720 , according to one embodiment of the present invention. Wedge  750  has wedge-shaped edges that work in concert with the force of spring  270 , wedge-shaped features  235  of outer shaft  710  and rotating indexer  740  to expand and contract stylus  700 . 
     Spring tube  730  of stylus  700  in  FIG. 7  functions, in one embodiment, to contain main spring  270 . In one embodiment of the present invention, main spring  270  exerts a force that locks a protruding feature on indexer  740  into a position with respect to outer shaft  710  so as to maintain stylus  700  in an expanded or contracted position. 
     Still referring to  FIG. 7 , tip housing  280  contains tip  290 , a smooth surface that functions to contact a touchscreen or digitizing tablet of a handheld device for the purpose of interfacing with the device. Tip housing  280  may also house a pen tip with ink cartridge that may allow stylus  700  to alternate between a stylus function and a pen function. 
       FIG. 8  is an exploded view  800  of an inner shaft  720  and plunger-type quill  210  of expandable and contractible stylus  700 , according to one embodiment of the present invention. Plunger-type quill  210  fits onto one end of inner shaft  720 . Quill  210  is joined to inner shaft  720  by a force fit, according to one embodiment. According to another embodiment, quill  210  and the end of inner shaft  720  are threaded so that quill  210  screws onto inner shaft  720 . 
     Inner shaft  720  has a main body  810  and a lower boss  820  onto which a secondary spring  830 , indexer  740  and wedge  750  fit, in accordance with one embodiment of the present invention. Secondary spring  830 , indexer  740  and wedge  750  are held on inner shaft  720  by a retaining device. In one embodiment, the retaining device is retaining screw  860 . In another embodiment, the retaining device is a retaining ring. Indexer  740  and wedge  750  can rotate freely around inner shaft  720  when retaining device  860  is in place and there is no main spring force applied. In order for wedge  750  to turn relative to indexer  740 , clearance is left on lower boss  820 . Secondary spring  830  takes up this clearance in the contracted and expanded positions. 
     Still referring to  FIG. 8 , indexer  740  has a number of evenly spaced raised features  745  that are designed, according to one embodiment, to slide into channels inside outer shaft  710  when the indexer  740  is positioned for expanding stylus  200 . Raised features  745  are designed to be captured by wedge feature  750  when in a contracted position, according to one embodiment. In one embodiment, raised features  745  are triangular in shape. These features can, however, be of any design that would slide into channels  715  in outer shaft  710  for expanding stylus  700  and be captured by features in wedge  750  when stylus  700  is contracted. 
       FIGS. 9A ,  9 B,  9 C and  9 D will be discussed below in concert with  FIG. 10  and with reference to  FIGS. 7 and 8 . In  FIGS. 9A ,  9 B,  9 C and  9 D, the outer tubes have been removed to illustrate one embodiment of the mechanism of stylus  700  at its critical points. 
       FIG. 9A  illustrates expandable and contractible stylus  700  in a depressed position  900   a  in transit from an expanded to a contracted position, according to one embodiment of the present invention.  FIG. 9B  is an illustration of expandable and contractible stylus  700  in a contracted position  900   b , according to one embodiment of the present invention.  FIG. 9C  is an illustration of expandable and contractible stylus  700  in a depressed position  900   c  in transit from a contracted to an expanded position, according to one embodiment of the present invention.  FIG. 9D  illustrates an expandable and contractible stylus in an expanded position  900   d , in accordance with one embodiment of the present invention. 
       FIG. 10  is a diagram  1000  showing the process of extending and compressing stylus  700 , according to one embodiment of the present invention. Although specific steps are disclosed in process  1000 , such steps are exemplary. That is, the present invention may be well suited to performing various other steps or variations of the steps recited in  FIG. 10 . 
     Beginning with stylus  700  in an extended position, at step  1010 , in order to actuate stylus to a compressed position, a user exerts downward axial force on quill  210  that, in turn, creates an axial force on indexer  740 . 
     Referring to  FIGS. 9A and 10 , at step  1020 , indexer  740  contacts a surface of wedge  750  and the surface interface converts some of the axial force to a torque on wedge  750 . The torque is opposed by a feature  235  of outer shaft  710 , in accordance with one embodiment of the present invention. 
     At step  1030  of diagram  1000 , according to one embodiment, as wedge  750  reaches the end of channel  715 , under the force of raised feature  745  on indexer  740  and main spring  270 , wedge  750  rotates in the direction of arrow  901  as shown in  FIG. 9A . 
     The user releases force from quill  210  in step  1040 . In one embodiment, the main spring  270  pushes wedge  750  into wedge-shaped feature  235  in outer shaft  710  where it remains captured in position  750   b . In the compressed position shown in  FIG. 9B , stylus  700  may be inverted or positioned in any orientation in space and quill  210  will remain in the compressed position, according to one embodiment. 
     Next, to actuate stylus  700  to an extended position, a user again applies force to quill  210 , as stated in step  1050  of  FIG. 10 , until wedge  750  clears the actuation point (shown as position  750   c  in  FIG. 9C ) at the tip of wedge shaped feature  235  of outer shaft  710 , according to one embodiment. 
     At step  1060 , once wedge  750  has cleared the tip of wedge shaped feature  235 , according to one embodiment, under the force of indexer  740  and main spring  270 , wedge  750  rotates into the next channel  715  in outer shaft  710 , assuming position  750   d  and expanding inner shaft  710  to extended position  900   d  as illustrated in  FIG. 9D . 
     The foregoing descriptions of specific embodiments have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.