Abstract:
A retractable pen includes an improved triggering device (i.e., an actuating means), which is easy for manufacturing and user-friendly. The retractable pen has a pen-body having two pen-tubes, a pen-cartridge within the pen-body, and an actuating means. The actuating means not only triggers the movement of pen-cartridge (slidable protrusion/retraction of the pen-cartridge) but also, at the meantime, triggers length-change of pen-body (slidable movement between the two pen-tubes).

Description:
This application claims the priority of Taiwan patent application No. 097145770 filed on Nov. 12, 2008. 
     BACKGROUND OF THE INVENTION 
     (1). Field of Invention 
     This invention relates to a pen; and more particularly relates to a pen with a retractable pen-cartridge (a retractable pen) that can elongate the length of its pen-body and project out the refill out of the pen point when the pressing part is pressed and provide sufficient length for holding the pen while writing, and shorten the length of the pen when the pressing part is pressed again to restore the refill in the pen point. 
     (2). Description of Related Art 
     Conventional retractable pens use either pushing or rotation for retracting/protruding its pen-cartridge and these retractable pens are normally designed to be long enough for easy writing. Their pen-body&#39;s length will provide difficulties to carry inside a small space (such as a packet, a wallet, or a purse). It is desirable to provide a retractable pen that has length adjustable capability—not only long enough for suitable handling the writing, but also short enough for easy carry. 
     Various devices have been disclosed to achieve this desirability. Among them, U.S. Pat. No. 6,832,868 (Dec. 21, 2004) to Hertwig and Nestlen describes a retractable pen whose triggering-device actuates the protrusion of its pen-cartridge, and, at the meantime, the same device actuates the lengthening its length; and vice versa by the same device after second another actuating step. However, the structure of the pen is complicate, and that of the triggering-device is mechanistically fragile. Accordingly, it is not only difficult to assemble/disassemble but also hard to perform routine maintenance by end users. It should thereby be appreciated to provide an improved triggering device for overcoming the above-mentioned shortcomings. 
     SUMMARY OF THE INVENTION 
     The present invention is drawn to a retractable pen that has an improved triggering device (i.e., an actuating means), which is easy for manufacturing and user-friendly. The retractable pen has a pen-body comprising: a pen-body that has two pen-tubes, a pen-cartridge within the pen-body, and an actuating means that not only triggers the movement of pen-cartridge (slidable protrusion /retraction of the pen-cartridge) but also, at the meantime, triggers length-change of pen-body (slidable movement between the two pen-tubes). 
     Several objects of the present invention are as follows: (1) to provide a retractable pen that has a actuating means (which not only actuates pen-cartridge&#39;s retraction and pen-body&#39;s shortening by one simple actuating step, thus the pen is easy to carry in a small space; but also actuates pen-cartridge&#39;s protrusion and pen-body&#39;s extending by another step, thus the pen is long enough for writing with the protruded pen-cartridge) and a simple-constructed pen-body; (2) to provide the actuating means that is mechanically simple, and simply constructed, thus the manufacture expense is reduced; (3) to provide such actuating means that, during routine maintenance, is easily assembled and disassembled by end users, thus user friendly is enhanced. Still further objects and advantages of present invention will become apparent from a consideration of the drawings and ensuing description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A &amp; 1B  are a perspective view and a cross-sectional view of one embodiment of the actuating mean of the present invention. 
         FIG. 2  is an isometric-exploded view of one embodiment of the present invention. 
         FIG. 3A &amp; 3B  are two plan views of two embodiments of the present invention at resting stage (where pen-cartridge is retracted within its pen-body, and the pen-body is shortened for easy carrying inside small area). 
         FIG. 4  is a cross-sectional view of  FIG. 3A . 
         FIGS. 5A ,  5 B &amp;  5 C are plan views of three embodiments of the present invention at working stage (where pen-cartridge is protruded outside its pen-body for writing, and the pen-body is elongated for easy handing the writing). 
         FIG. 6  is a cross-sectional view of  FIG. 5A . 
     
    
    
     REFERENCE NUMERALS IN DRAWINGS 
     Reference numerals used herein are as follows: 
     
       
         
               
               
             
           
               
                   
               
             
             
               
                 1 
                 Lower Pen-Tube 
               
               
                 11 
                 First Opening 
               
               
                 111 
                 First Pattern 
               
               
                 12 
                 Pen-Point 
               
               
                 13 
                 Stop-Ring 
               
               
                 2 
                 Upper Pen-Tube Unit 
               
               
                 21 
                 Pressing Part 
               
               
                 211 
                 First-Joint 
               
               
                 22 
                 Inner-Sleeve 
               
               
                 221 
                 Second Pattern 
               
               
                 23 
                 Pen-Clip 
               
               
                 24 
                 Upper Pen-Tube 
               
               
                 241 
                 Window 
               
               
                 25 
                 Bushing Ring 
               
               
                 3 
                 Retractable-Core-Rod 
               
               
                 31 
                 Lug 
               
               
                 32 
                 Slide-Groove 
               
               
                 33 
                 Second-Joint 
               
               
                 4 
                 Jump key Unit 
               
               
                 41 
                 Stationary-Cam-Sleeve 
               
               
                 411 
                 Stop-Edge 
               
               
                 412 
                 First-Rib 
               
               
                 413 
                 Second-Rib 
               
               
                 414 
                 First-Rib-Slant 
               
               
                 415 
                 Second-Rib-Slant 
               
               
                 416 
                 First-Cam-Groove 
               
               
                 417 
                 Second-Cam-Groove 
               
               
                 418 
                 Stop-Limit 
               
               
                 42 
                 Plunger 
               
               
                 421 
                 Guide-Block 
               
               
                 422 
                 Flat Rib 
               
               
                 423 
                 Upper-Toothed Part 
               
               
                 43 
                 Rotating Cam 
               
               
                 431 
                 Channel 
               
               
                 432 
                 Stop-Block 
               
               
                 433 
                 Lower-Toothed Part 
               
               
                 434 
                 Key-Rib 
               
               
                 435 
                 Cam-Groove 
               
               
                 436 
                 Clinch-Joint 
               
               
                 44 
                 First-Spring 
               
               
                 5 
                 Pen-Refill Unit 
               
               
                 51 
                 Pen-Refill Tube 
               
               
                 511 
                 First-Ring-Pad 
               
               
                 512 
                 Sleeve-Joint 
               
               
                 52 
                 Second-Spring 
               
               
                 53 
                 Pen-Refill Sleeve 
               
               
                 531 
                 Second-Opening 
               
               
                 532 
                 Second-Ring-Pad 
               
               
                 54 
                 Pen-Cartridge 
               
               
                 55 
                 Third-Spring 
               
               
                   
               
             
          
         
       
     
     DETAILED DESCRIPTION 
     The present invention provides a retractable pen that has a pen-body comprising two pen-tubes, and a device for linking the capability of protrusion/retraction the pen-cartridge with the ability of extending/shortening its pen-body. Such device is termed as an actuation means herein. Particularly, the actuating means links the protrusion of its pen-cartridge with the extension of its pen-body&#39;s length by a slidable movement between the two pen-tubes. 
     Also used herein: Pen means any writing device/implement; Spring means any elastic element; Resting stage means the stage where pen cartridge is retracted within its pen-body and the pen-body is shortened ( FIGS. 3A-3B  &amp;  4 ); Working stage means the stage where pen-cartridge is protruded outside its pen-body ( FIGS. 5A-5C  &amp;  6 ). 
     A. The Preferred Embodiment of the Present Invention 
     The pen of the present invention comprises: (1) a pen body; (2) a pen-refill unit  5 , which contains a pen-cartridge  54  inside the pen body; and (3) an actuating means, which has a retractable-core-rod  3  and a jump key unit  4  ( FIG. 1A &amp; 1B ). 
     (1) Pen Body 
     Pen body has: (a) a lower pen-tube  1  and (b) an upper pen-tube  2  being slidably mounted to lower pen-tube  1  either inside ( FIGS. 3A ) or outside ( FIGS. 3B ). 
     a. Lower Pen-Tube  1   
     Forming a pen-point  12  with a passage at the bottom for allowing the protrusion of pen-cartridge  54  ( FIGS. 5A-5C ). Within lower pen-tube  1  and above pen-point  12 , a stop-ring  13  is disposed ( FIGS. 4 &amp; 6 , as well as  FIG. 2 ). 
     Stop-ring  13  delimits concentrically an first opening  11 . Instead of an integral part, the pen-point  12  can be a separated part, attached to lower pen-tube  1  ( FIG. 2 ) for allowing easy replacement of pen-cartridge  54 . 
     b. Upper Pen-Tube Unit  2   
     Upper pen-tube Unit  2  is movably and slidably mounted with lower pen-tube  1  either outside or inside ( FIG. 3 &amp; 5 ). It comprises an upper pen-tube  24 , an inner-sleeve  22  situated within upper pen-tube  24 , and a pressing part  21  at the top. 
     Pressing part  21  has, at the bottom, a first-joint  211 ( FIG. 2 ) whose bottom end is contoured as a female for mating with the male of actuating means (i.e., second-joint  33 ). The diameter of first-joint  211  is small than that of pressing part  21 , whereby a gap-portion is formed underneath pressing part  21 . This gap-portion serves as a bias for one elastic component of actuating means (i.e., first-spring  44 ). 
     As a ramification of the preferred embodiment, upper pen-tube  2  may further has a bushing ring  25  below upper pen-tube  24  for reducing the undesirable abrasion, caused by the slidable movement between lower pen-tube  1  and upper pen-tube  2 , as well as a pen-clip  23  attached for easy carrying the pen (detailed in RAMIFICATION infra). 
     (2) Pen-Refill Unit  5   
     Pen-refill unit  5  is coaxially disposed around the center of the pen body ( FIGS. 4 &amp; 6 ). The pen-refill unit  5  is disposed inside a retractable-core-rod  3 , that is provided with an first-ring-pad  511 . One side of the first-ring-pad  511  is in close contact with a rotating cam  43 , and the other side of the first-ring-pad  511  is supported by a second-spring  52 . It comprises: (1) a pen-cartridge  54 , coaxially situated around the center of the pen body; (2) a pen-refill tube  51 , coaxially surrounded pen-cartridge  54 , that has, on the outer surface, a first-ring-pad  511  that delimits a sleeve-joint  512  at the bottom; (3) a second-spring  52 , disposed below pen-refill tube  51 , that pushes against first-ring-pad  511  upward of pen-refill tube  51  and against one part of pen-point  12  downward; and (4) a third-spring  55 , disposed below rotation cam  43 , that one end to lean against stop-ring  13  and against one part of under actuating means (i.e., clinch-joint  436 ). Both sides of first-ring-pad  511  of the pen-refill unit  5  respectively leant against the rotating cam  43  and the second-spring  52 . Optionally, pen-refill unit  5  has a pen-refill sleeve  53  positioned pen-refill tube  51  underneath (detailed in RAMINFICATION infra). 
     (3) Actuating Means 
     Actuating means is an essential part of the present invention. It actuates not only the retraction/protrusion of pen-cartridge  54  but also the lengthening/shortening of the pen body. It has (a) a retractable-core-rod  3  and (b) a jump key unit  4 . ( FIGS. 1A-1B  &amp;  2 ) 
     a. Retractable-Core-Rod  3   
     Retractable-core-rod  3  comprises at least one slide-groove  32  formed on an external side thereof, and at least one lug  31  is formed on a periphery of one end thereof and a second-joint  33  formed on another end. The retractable-core-rod  3  is movably disposed in the jump key unit  4  to move simultaneously with the upper pen-tube unit  2  in conjunction with the jump key unit  4 . The second-joint  33  is disposed at one end of the retractable-core-rod  3  and securely jointed to first-joint  211  by various jointing methods such as head-hinge, embedding, or screw-joint). The retractable-core-rod  3  comprises at least one wedge-like block (i.e., lug  31 ) at one end for mating to a wedge-like protruded counterpart of Jump Key Unit  4  (i.e., stop-block  432 ). The slide-groove  32  is disposed between lug  31  and second-joint  33  ; the retractable-core-rod  3  comprises at least one groove (i.e., slide-groove  32 ) on exterior surface thereof that run upward to second-joint  33  and downward before lug  31 , that slides within the protrusion-counterpart of jump key unit  4  (i.e., guide-block  421 ). 
     b. Jump Key Unit  4   
     Jump key unit  4  has: (1) an stationary-cam-sleeve  41  fixed inside the lower pen-tube  1 , (2) a first-spring  44 , (3) an rotating cam  43 , and (4) an plunger  42  operates in conjunction with the retractable-core-rod  3  and the stationary-cam-sleeve  41  ( FIG. 2 ) 
     [1] Stationary-Cam-Sleeve  41   
     Stationary-cam-sleeve  41  has: (1) a stop-edge  411 , (2) a second-rib  413 , (3) a first-rib  412 , (4) a first-cam-groove  416  that shallower than second-cam-groove  417 , (5) a second-cam-groove  417 , (6) a stop-limit  418 , and (7) a slant means that has first-rib-slant  414  and a second-rib-slant  415 . ( FIGS. 1A &amp; 1B ) 
     Stop edge  411  is a ring-like structure at one edge ( FIG. 1A ). At predetermined positions, stop-edge  411  extends downward in a pair-fashion, preferably equally spaced, and with different thickness, formed on one peripheral end of the stationary cam sleeve  41 , and a plurality of ribs and grooves are formed on the inner edge of the stationary cam sleeve  41 . 
     While essentially no downward extension makes deep groove (termed as a second-cam-groove  417 ), thin downward extension makes shallow groove (termed as a first-cam-groove  416 ). Accordingly, first-cam-groove  416  is shallower than second-cam-groove  417 . 
     A pair of cam-grooves  416  and  417  is sandwiched by a pair of ridges, which are formed when stop-edge  411  extends downward in a thick fashion, preferably with the same thickness as stop-edge  411 . After passing cam-grooves  416  and  417 , the thick downward extension of stop-edge  411  bevels sideward forming a pair of corresponding bevel ends. Depending on the relative position to first-cam-groove  416 , a pair of ridges (with their corresponding bevel ends) is termed differently as: a first-rib  412 , a second-rib  413 , and their corresponding bevels end as a first-rib-slant  414  and a second-rib-slant  415 . Because the thin extension of first-cam-groove  416  terminates at the bevel end of the ridges, not only it is shallower than second-cam-groove  417 , but also it is shorter than the ridges. 
     [2] First-Spring  44   
     First-spring  44  component disposed on the retractable-core-rod  3  with both ends thereof respectively head hinged against the upper pen tube unit  2  and the stationary cam sleeve  41 . It is coaxially located above stop-edge  411 . ( FIGS. 2 ,  4  &amp;  6 ) It not only held the stop-edge  411  but also passing first-joint  211  and pressing part  21 . 
     [3] Rotating Cam  43   
     Rotating cam  43  has a channel  431 , a stop-block  432 , a lower-toothed part  433 , a key-rib  434 , a cam-groove  435 , and a clinch-joint  436 . ( FIG. 1A , bottom row) 
     Channel  431  is disposed around the center of rotating cam  43 . At least one stop-block  432  is placed within channel  431  for serving as a male (i.e., tenon-like protrusion) who interlocks the lug  31 , so that jump part unit  4  interlocks retractable-core-rod  3  in a dovetail-like fashion. 
     The top of the rotating cam  43  is circumferentially formed with lower-toothed part  433 . The lower-toothed part  433  operate in conjunction with and engage with upper-toothed part  423  circumferentially formed in the bottom of the plunger  42 . A plurality of key-rib  434  and cam-groove  435  are peripherally formed across the surface of the rotating cam  43 . The key-rib  434  is movable along a second-cam-groove  417  of the stationary-cam-sleeve  41  or abuts against a second-rib-slant  415  of the stationary-cam-sleeve  41 . A first-rib  412  and a second-rib  413  of the stationary-cam-sleeve  41  can slide along the cam-groove  435  of the rotating cam  43 ; then the serrated internal part is further extended outward in a pair-fashion, forming a least one pair of ridges (termed as key-rib  434 ), spaced by at least one pair of cam-grooves  435 , and a serrated lower-toothed part  433  on the top thereof. 
     [4] Plunger  42   
     Plunger  42  comprises a plurality of flat rib  422  disposed on an exterior edge thereof, and least one guide-block  421 , and an upper toothed part  423  on one end thereof (a plurality  42  of flat ribs  422  are disposed on the peripheral edge of one end of the plunger  42 , and an upper toothed part  433  is disposed on the peripheral edge of one end of the plunger  42 .); that is disposed not only concentrically around retractable-core-rod  3  ( FIGS. 4 &amp; 6 ) but also above rotating cam  43  ( FIG. 2 ). As illustrated in  FIGS. 1A &amp; 1B , it has: (1) a guide-block  421 , disposed on the top portion of the inner surface of the hollow-tube; (2) a plurality of flat rib  422 ; and (3) an upper toothed part  423  disposed on the bottom surface. 
     The plunger  42  correspondingly moves with the joint of the upper pen tube unit  2 , at least is formed on a guide-block  421  sliding in the slide-groove  32  of the retractable-core-rod  3 , and at least one stop-block  432  inside the rotating cam  43  allowing the lug  31  to move and stopped. 
     When third-spring  55  pushes rotating cam  43  upward, plunger  42  meets rotating cam  43 . When rotating cam  43  meets plunger  42 , upper-toothed part  423  mates lower-toothed part  433  for avoiding rotational displacement between plunger  42  and rotating cam  43 . A slide-groove  32  of the retractable-core-rod  3  and a guide-block  421  of the plunger  42  allow the retractable-core-rod  3  to move within a jump key unit  4  comprised by stationary-cam-sleeve  41 , plunger  42 , and rotating-cam  43 . The lug  31  of the retractable-core-rod  3  and the stop-block  432  of the rotating-cam  43  allow the retractable-core-rod  3  to move within the jump key unit  4 . 
     B. Ramification of the Preferred Embodiment 
     The above-mentioned embodiments are the preferred embodiments and some of the best modes of carrying out the invention. They are intended to illustrate but not to limit the present invention. It will be apparent to one skilled in the art that various substitutions and modifications may be made to the invention disclosed herein without departing form the scope and the spirit of the invention. For example: 
     Pen-point  12  may be an integral embodiment to the present invention, instead of a separated element. A pen-chip  23  may attach to the retractable pen of the present invention for easy carry. As illustrated in ( FIGS. 2 ,  3 A &amp;  5 A), pen-clip  23  is attached to the pressing part  21  of the upper pen-tube  2 . 
     Further, upper pen-tube  2  may has a bushing ring  25  below upper pen-tube  24  for reducing the undesirable abrasion, caused by the slidable movement between lower pen-tube  1  and upper pen-tube  2 , as well as a pen-clip  23  attached for easy carrying the pen (detailed in RAMIFICATION). Pen-refill sleeve  53  has (1) a second-opening  531  in the center, and (2) a second-ring-pad  532  fringed around the upper end (illustrated in  FIGS. 2 ,  5 A,  5 B &amp;  6 ). When pen-refill tube  51  is inserted into second-opening  531 , first-ring-pad  511  will touch second-ring-pad  532 , whereby sleeve-joint  512  is disposed within pen-refill sleeve  53 . In this ramification, second-ring-pad  532  is situated under the first-ring-pad  511  and is pushed against by the upper end of second-spring  52 . More preferably, pen-refill sleeve  53  is tempered downward, whereby a tempered end is formed. The tempered end is contoured to match the shape of protruded end of pen cartridge  54  for aesthetical appeal and for easy writing ( FIGS. 5A &amp; 5B ). 
     For esthetic appearance, lower pen-tube  1  can has a first pattern  111  on the surface ( FIGS. 2 ,  3 A &amp;  3 B). The present invention can have means for changing aesthetic appearance. Here, upper pen-tube  2  has both a second pattern  221  situated on the outer surface of inner-sleeve  22  and a window  241  situated at a predetermined position on the surface of upper pen-tube  24 . Depending on the relatively geological location to window  241 , first pattern  111  can be seen through window  241  either when pen body is retracted (at the rest position,  FIG. 3A ), second pattern  221  can be seen through window  241  either when pen body is extended (at working stage,  FIG. 5A ). 
     These and many other variations are intended to be within the scope of the present invention. Accordingly, the scope of the invention should be determined by the claims and their legal equivalents, rather than the embodiments given. 
     C. The Best Modes of Carrying Out the Invention 
     The momentum of the present invention is provided by three elastic elements: first-spring  44 , second-spring  52 , and third-spring  55  ( FIG. 2 ). While elastic elements expend, they push both sides (upward and downward). The springs used in the present invention, however, are biased onto one integral component of the pen. Accordingly, they push unidirectionally: (a) First-spring  44 , biased on first-joint  211 , on its stop-edge  411 ; (b) Second-spring  52 , biased on pen-point  12 , pushes pen-refill tube  51  upward, on its first-ring-pad  511 ; (c) Third-spring  55 , disposed on one end of the lower pen tube  1  with both ends thereof respectively head hinged against the rotating cam  43  and the stop-ring  13 , biased on stop-ring  13 , pushes rotating cam  43  upward, on its clinch-joint  436 . Thereby keeping the rotating cam  43  head hinged by the third-spring  55 , and thereby maintaining its correct linked motion position within the lower pen tube  1 . 
     The mechanical joints of the preferred embodiment are also detailed supra. Comparing working stage ( FIG. 6 ) with resting stage ( FIG. 4 ), one should notice that mechanical linkage between retractable-core-rod  3  and jump key unit  4  varies: While they separate, resulting to the elongated pen-body at working stage ( FIG. 6 ); while they interlock in a dovetail-like fashion lug  31  mates with stop-block  432 , resulting to the shortened pen-body at the resting stage ( FIG. 4 ). 
     The locking/unlocking is controlled a cam (wheeling device) that can be triggered by either a simple rotation or a simple pressing (for illustrative purpose, the preferred embodiment uses the pressing). The functionality of the cam is included in the actuating means of the presenting invention. Not only the actuating mean locks/unlocks the mating between lug  31  and stop-block  432 , but also it changes the pen-body length (summarized below): 
     First, the unique configuration of jump key unit  4 , plunger  42 , and rotating cam  43 : Variation of thickness of thin parts of plunger  42  (flat rib  422 ) allows then sliding within and along the shallow groove (first-cam-groove  426 ) and the deep groove (second-cam-groove  417 ) of stationary-cam-sleeve  41 , the protruded parts of rotating cam  43  (key-rib  434 ) allows then sliding within and along the deep groove of stationary-cam-sleeve  41  (second-cam-groove  417 ). Accordingly, one elongation of the pen-body is be archived. 
     Second, the upward movement of retractable-core-rod  3 , which is secularly connected to upper pen-tube  2 : When retractable-core-rod  3  is unlocked from the joint with jump key unit  4 , two compressed springs (second-spring  52  &amp; third-spring  55 ) relax. The combined elasticity of the two compressed springs overcomes the elasticity of the spring above (first-spring  44 ) and pushes upward retractable-core-rod  3  moves upward. The upward movement of retractable-core-rod  3  also moves its conjunctive upper pen-tube  2  upward. The upward movement of upper pen-tube  2 , thus, slides along the lower pen-tube  1  results in another elongation of the pen-body. One skilled in the art will notice that the length of retractable-core-rod  3  can be in any predetermined, thereby the body length of the pen in the present invention can be configured in any predetermined length, delimited by the length of retractable-core-rod  3 . This is another distinctive feature of the present invention. 
     The mode of operation is detailed further below: 
     Staring from the resting stage ( FIG. 4 ), here lug  31  mates to stop-block  432  by pressing  21 , which is securely attached to the retractable-core-rod  3  by a strong mechanical joint between first-joint  211  and second-joint  33 . The mating (interlocking) compresses first-spring  44  from its more relaxed state to more compressed state, but relaxes both compressed springs (second-spring  52  and third-spring  55 ) from their more compressed state to their more relaxed state so that both springs regain their elasticity. While third-spring  55  pushes rotating cam  43  upward on its clinch-joint  436 , second-spring  52  pushes pen-refill tube  51  upward on its first-ring-pad  511 . Because pen-cartridge  54  is situated coaxially within pen-refill tube  51 , pen-cartridge  54  is retracted within the pen-body. At the resting stage, user can change pen-cartridge  54  simply by removing its pen-point  12 . 
     When users want to write (changing from resting stage to working stage), they simply push pressing part  21  again. The second push unlocking the mechanical joint between lug  31  and stop-block  431 . The unlocking relaxes the first-spring  44  from the more compressed to more relaxed state, but compresses both second-spring  52  and third-spring  55  from their more relaxed state to more compressed state. The more relaxed second-spring  52  and third-spring  55  regain their elasticity. While third-spring  55  pushes rotating cam  43  onto its clinch-joint  436  upward, second-spring  52  pushed pen-refill tube  51  upward on its first-ring-pad  511 , whereby the pen-body&#39;s is elongated and pen-cartridge  54  is protruded outside the pen-body ( FIG. 6 ) in the manner summarized as follows: 
     For writing, the user may: 
     
         
         (1) Directly press on the end of upper pen-tube  2  to cause upper pen-tube  2  to move downward conjunctively with first-joint  211  and retractable-core-rod  3  toward rotating cam  43 . The movement is slidable and guided by plunger  42  through the mating between female (slide-groove  32  of retractable-core-rod  3 ) and male (guide-block  421  of plunger  42 ), allowing slide-groove  32  of to slide through, such that first-joint  211  of upper pen-tube  2  pushes plunger  42 . 
         (2) In the meantime, flat rib  422  of plunger  42  moves downward in first-cam-groove  416  and second-cam-groove  417  of stationary-cam-sleeve  41 , and cam-groove  435  of the rotating cam  43  slides upward on first-rib  412  and second-rib  413  of the stationary-cam-sleeve  41 , thus enabling plunger  42  to use the slant structure of the upper-toothed part  423  on the edge to push lower-toothed part  433  of rotating cam  43  to rotate the rotating cam  43 , forcing key-rib  434  of the rotating cam  43  to separate from second-cam-groove  417  of stationary-cam-sleeve  41 , thereby head hinging against second-rib  413  and second-rib-slant  415  at the bottom end of first-cam-groove  416 , using one end of the first-rib  412  as the motion limitation. 
         (3) Meanwhile, cam-groove  435  of rotating cam  43  separate from first-rib  412  and second-rib  413  of stationary-cam-sleeve  41 , and as rotating cam  43  rotates, it causes stop-block  432  of rotating cam  43  to leave from lug  31  of retractable-core-rod  3 , thereby allowing lug  31  of retractable-core-rod  3  to slide in channel  431  of rotating cam  43 , enabling the release of first-spring  44  to push upper pen-tube  2  upward, rotating cam  43  moving downward accordingly, making pen-refill sleeve  53  on one end of pen-refill unit  5  to protrude pen-point  12  and simultaneously compressing second-spring  52 .
 
In this way, it is possible to release the upper pen-tube  2  and the pen-refill-unit  5  to expose the pen-cartridge  54  of the pen-refill unit  5  to allow the user to write.
 
       
    
     When users finish writing, the push changes again from the working state to resting state. The process is summarized below. 
     Upon completion of writing, the user may perform the retraction operation to retract the refill of the writing implement as follows. Similarly, the top end of the upper pen-tube  2  may be pressed to cause the upper pen-tube  2  to move the retractable-core-rod  3  and the first-joint  211  conjunctively downward, thus making the slide-groove  32  of the retractable-core-rod  3  start to slide through the guide-block  421  of the plunger  42  to allow the first-joint  211  of the upper pen-tube  2  to push the plunger  42 ; at this moment, the flat rib  422  of the plunger  42  moves downward in the first-cam-groove  416  and second-cam-groove  417  of the stationary-cam-sleeve  41 , causing the plunger  42  to push lower-toothed part  433  of the rotating cam  43  by using the slant structure of the upper-toothed part  423  on the end edge thereof to rotate the rotating cam  43 , pushing the key-rib  434  of the rotating cam  43  to separate from the second-rib  413  and the second-rib-slant part  415  on the bottom end of the first-cam-groove  416 , thus sliding and head hinging against the first-rib-slant  414  of the first-rib  412  and entering into the second-cam-groove  417  of the stationary-cam-sleeve  41 , meanwhile, the cam-groove  435  of the rotating cam  43  moving onto the first-rib  412  and second-rib  413  of the stationary-cam-sleeve  41 ; while the rotating cam  43  rotates, it simultaneously causes the lug  31  of the retractable-core-rod  3  to slide in the channel  431  of the rotating cam  43 , stopped at the end edge of the stop-block  432  of the rotating cam  43 , allowing the lower pen-tube  1  to retract toward inside of the upper pen-tube  2  and compress the first-spring  44 , and the lug  31  of the retractable-core-rod  3  also bring the rotating cam  43  to move upward, enabling the release of the second-spring  52 , thereby retracting the writing end of the pen-cartridge  54  in the pen-refill-unit  5  into the pen-point  12 , thus completing the limited retraction of the upper pen-tube  2  and the pen-refill-unit  5  to facilitate convenience and portability. Accordingly, the present invention can meet user&#39;s demands in a more advanced, practical and satisfactory fashion, which conforms to various requirements on patent application as disclosed herein for legal protection.