Abstract:
A retractile pen includes axially slidably connected front and rear casings, an internal sleeve slidably mounted in the rear casing to hold an ink cartridge having a front portion extended into the front casing, and an adjusting button located above a guide slot provided on the rear casing to connect with the internal sleeve via a stem portion extended from the adjusting button through the guide slot. When the adjusting button is depressed and moved to a rear or a front end of the guide slot, the internal sleeve is held in place to retract or extend the ink cartridge, respectively, and the rear casing may be pushed toward or away from the front casing to shorten or increase an overall length of the pen.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a retractile pen, and more particularly to a pen including slidably connected front and rear casings, so that the pen may be shortened for storage, or extended for comfortable holding during writing. 
     BACKGROUND OF THE INVENTION 
     There are a variety of retracting structures designed for pens. For example, U.S. Pat. No. 6,276,855 B1 discloses a retractile pen, a casing of which may be shortened to enable positioning of the pen in a small pocket, or extended to enable easy holding and comfortable writing. 
     It is desirable to develop a new retractile pen that may be easily operated to a retracted state for storage or an extended state for writing. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a retractile pen that includes axially slidably connected front and rear casings, an internal sleeve slidably mounted in the rear casing to hold an ink cartridge, a front portion of which is extended into the front casing, and an adjusting button located above a guide slot provided on the rear casing to connect to the internal sleeve via a stem portion of the button extended through the guide slot. When the adjusting button is depressed, it may be moved along the guide slot to bring the internal sleeve to a rear or a front locating hole formed at rear and front end of the guide slot, respectively, so as to hold the ink cartridge in a retracted or extended position. Meanwhile, when the adjusting button is depressed, the rear casing may be pushed toward or away from the front casing to shorten or increase an overall length of the pen, respectively. 
     The retractile pen of the present invention further includes a clip connected to the rear casing. The clip is provided with an axially extended slide slot corresponding to the guide slot on the rear casing. The adjusting button is located at an outer side of the clip with the stem portion extended through the slide slot and the guide slot to connect with the internal sleeve. When the adjusting button is moved to the front end of the slide slot to hold the internal sleeve in place and the ink cartridge in the extended position, the stem portion stops the clip from opening to clamp the pen to a pocket, protecting the pocket from being smudged by an exposed writing tip of the ink cartridge. 
     The adjusting button may have a selected size and shape to enable convenient operation by a user, and specific patterns may be printed on a top of the adjusting button as an advertisement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
     FIG. 1 is an exploded perspective view of a retractile pen according to the present invention; 
     FIG. 2A is an assembled perspective view of the retractile pen of FIG. 1 in a fully retracted state for storage; 
     FIG. 2B is an assembled perspective view of the retractile pen of FIG. 1 in a half-extended state; 
     FIG. 2C is an assembled perspective view of the retractile pen of FIG. 1 in a fully extended state for writing; 
     FIG. 3A is a sectioned side view of FIG. 2A; 
     FIG. 3B is a sectioned side view of FIG. 2B; and 
     FIG. 3C is a sectioned side view of FIG.  2 C. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to FIGS. 1,  2 A, and  3 A, in which a retractile pen  1  according to the present invention is shown. As shown, the retractile pen  1  mainly includes a front casing  10 , a rear casing  20 , an internal sleeve  30 , and an adjusting button  40 . 
     The front casing  10  includes a diameter-reduced rear section  11 , around a rear end of which a first stop flange  12  is provided to radially inward and outward project from the rear end. 
     The rear casing  20  is provided at a front end with a second stop flange  21  that radially inward projects from the front end. The rear casing  20  is axially slidably mounted around the diameter-reduced rear section  11  of the front casing  10 , such that the second stop flange  21  abuts against the first stop flange  12  when the front casing  10  is fully moved forward relative to the rear casing  20 , preventing the front casing  10  from completely separating from the rear casing  20 , as shown in FIGS. 3B and 3C. An axially extended guide slot  22  is provided on the rear casing  20 . Front and rear ends of the guide slot  22  are formed into two locating holes  23 ,  24  having a diameter slightly larger than a width of the guide slot  22 . 
     The internal sleeve  30  is axially slidably mounted in the rear casing  20  behind the diameter-reduced rear section  11  of the front casing  10 . The internal sleeve  30  includes a diameter-reduced front section  31  adapted to forward extend into the rear section  11  of the front casing  10 , and a diameter-expanded rear section  33 . A third stop flange  32  is provided around a front end of the front section  31  to radially outward project therefrom. The third stop flange  32  is adapted to abut against the first stop flange  12  when the internal sleeve  30  is rearward moved relative to the front casing  10 , and thereby prevents the internal sleeve  30  from completely separating from the front casing  10 , as shown in FIGS. 3A and 3B. A hollow front cap  13  is connected to an open front end of the front casing  10 , so that an ink cartridge  50  having a rear portion inserted in the diameter-reduced front section  31  of the internal sleeve  30  and a front portion extended into the front casing  10  may be forward moved to expose a writing tip  51  from the front cap  13 . A spring  14  is mounted on the ink cartridge  50  behind the front cap  13 . The rear section  33  of the internal sleeve  30  is fitly received in the rear casing  20  to smoothly slide axially. A shoulder portion is formed between the expanded rear section  33  and the reduced front section  31 , and is adapted to abut against the first stop flange  11  when the internal sleeve  30  is fully moved forward relative to the rear casing  20 , as shown in FIG.  3 C. 
     The rear section  33  of the internal sleeve  30  is provided at one side with a radially extended hole  34 , in which a hollow retaining block  35  having a restoring spring  36  mounted therein is received. The retaining block  35  includes a diameter-reduced top  351  having a configuration corresponding to that of the front and rear locating holes  23 ,  24  of the guide slot  22  on the rear casing  20 . When the internal sleeve  30  is axially moved in the rear casing  20 , the retaining block  35  and the reduced top  351  are normally located below the guide slot  22 , and when the reduced top  351  reaches at the front or the rear end of the guide slot  22 , the reduced top  351  is allowed to project from the expanded front or rear locating hole  23 ,  24  and thereby stops the internal sleeve  30  from moving forward or rearward any further. 
     The adjusting button  40  includes a stem portion  41  that is extended through the guide slot  22  on the rear casing  20  into the diameter-reduced top  351  of the retaining block  35 , and thereby brings the internal sleeve  30  to move along with the adjusting button  40 . 
     A rear cap  60  is connected to a rear end of the rear casing  20  with a clip  61  forward extended from one side of the rear cap  60  to fitly press against an outer surface of the rear casing  20  and fixedly located immediately above the guide slot  22 . The clip  61  is provided with an axially extended slide slot  62  corresponding to the guide slot  22 . The adjusting button  40  is located on an outer side of the clip  61  with the stem portion  41  extended through the slide slot  62  into the guide slot  22  and the reduced top  351  of the retaining block  35 . 
     Please refer to FIGS. 2A and 3A. When the pen  1  is not in use and to be stored, the adjusting button  40  connected to the retaining block  35  is depressed and fully moved rearward along the slide slot  62 , allowing the reduced top  351  of the retaining block  35  to upward project into the expanded rear locating hole  24  and thereby holds the internal sleeve  30  to a rearmost position in the rear casing  20 . At this point, the ink cartridge  50  is in a retracted position and the writing tip  51  is completely located in the front cap  13 , and the rear casing  20  may be pushed toward the front casing  10  until the second stop flange  21  at the front end of the rear casing  20  is abutted on the front casing  10 . The pen  1  will have a shortest possible length in this state and may be conveniently put in a pocket. 
     Please refer to FIGS. 2B and 3B. When it is desired to use the pen  1  to write, first depress the adjusting button  40  to disengage the reduced top  351  of the retaining block  35  from the rear locating hole  24  on the rear casing  20 , and then pull the rear casing  20  rearward to expose the rear section  11  of the front casing  10 , so as to extend the length of the pen  1 . Meanwhile, the depressed adjusting button  40  is gradually moved along the guide slot  22  toward the front locating hole  23 , and the ink cartridge  50  is still in a retracted position without exposing the writing tip  51  from the front cap  13 . 
     Please refer to FIGS. 2C and 3C. When the depressed adjusting button  40  is further moved to locate the retaining block  35  below the front locating hole  23  and released, the internal sleeve  30  is moved to a most front end of the rear casing  20  with the reduced top  351  of the retaining block  35  upward engaged with the front locating hole  23 , allowing the writing tip  51  of the ink cartridge  50  to expose from the front cap  13  and be held to this extended position. The pen  1  in the extended state has an increased length to enable comfortable holding of the pen  1  for writing. An elastic force from the spring  14  makes the ink cartridge  50  firmly located between the internal sleeve  30  and the front cap  13 . When the pen  1  is operated to return to the retracted state, a rearward restoring force from the spring  14  enables the internal sleeve  30  to move rearward more easily. 
     As can be clearly seen from FIGS. 2C and 3C, when the adjusting button  40  is held to the most front end of the slide slot  62  on the clip  61  through engagement of the reduced top  351  of the retaining block  35  with the front locating hole  23  on the guide slot  22 , the stem portion  4 l of the adjusting button  40  forms a stopper at a front end of the clip  61 . When a user intends to clamp the pen  1  in the extended state to a pocket using the clip  61 , the stem portion  41  of the adjusting button  40  at the front end of the slide slot  62  stops the clip  60  from opening for use. Therefore, the risk of a smudged pocket due to the exposed writing tip  51  may be effectively eliminated. 
     The adjusting button  40  may be designed according to body engineering to facilitate easy and comfortable push or operation thereof. Moreover, patterns may be selectively printed on a top of the adjusting button  40  to provide an advertising effect.