Patent Publication Number: US-8985882-B2

Title: Two piece twist action retractable writing instrument

Description:
SUMMARY 
     The present invention provides a retractable writing instrument with a twisting mechanism for retracting an ink cartridge which is incorporated into cap and barrel components. Cartridge retraction/extension mechanism features are integral to the barrel and cap, so no additional components are required. 
     The invention comprises, in one form thereof; a retractable pen including an elongate cartridge having a first end and a second end. A cap includes a recess having an inner surface with first threads thereon. The cartridge is partially received in the recess such that the first end of the cartridge is fixedly attached to the cap. An elongate barrel includes first and second open ends and a through channel fluidly interconnecting the first and second open ends. A portion of the barrel has an outer surface with second threads thereon. The portion of the barrel including the first open end is snugly received in the recess such that the first and second threads are in threaded engagement with each other, the cartridge is received in and extends through the through channel, and the barrel and the cap are rotatingly movable relative to each other via the threaded engagement between an extended position in which the second end of the cartridge extends through and out of the second open end of the barrel, and a retracted position in which the second end of the cartridge is disposed within the barrel. 
     The invention comprises, in another form thereof, a retractable pen including an elongate ink cartridge having a first end and a second end. A cap includes a recess having an inner surface with first threads thereon. The cartridge is partially received in the recess such that the first end of the cartridge is fixedly attached to the cap. An elongate barrel includes first and second open ends and a through channel fluidly interconnecting the first and second open ends. A portion of the barrel has an outer surface with second threads thereon. The portion of the barrel including the first open end is snugly received in the recess such that the first and second threads are in threaded engagement with each other, the cartridge is received in and extends through the through channel, and the barrel and the cap are rotatingly movable relative to each other via the threaded engagement between an extended position in which the second end of the cartridge extends beyond the second open end of the barrel, and a retracted position in which the second end of the cartridge is disposed within the barrel. A first ring is attached to the barrel and engages the first threads on the cap in the retracted position. A second ring is attached to the barrel and engages the first threads on the cap in the extended position. 
     The invention comprises, in yet another form thereof, a retractable pen including an elongate ink cartridge having a first end and a second end. A cap includes a recess having an inner surface with first threads thereon. The cartridge is partially received in the recess such that the first end of the cartridge is fixedly attached to the cap. An elongate barrel includes first and second open ends and a through channel fluidly interconnecting the first and second open ends. A portion of the barrel has an outer surface with second threads thereon. The portion of the barrel including the first open end is snugly received in the recess such that the first and second threads are in threaded engagement with each other, the cartridge is received in and extends through the through channel, and the barrel and the cap are rotatingly movable relative to each other via the threaded engagement between an extended position in which the second end of the cartridge extends beyond the second open end of the barrel, and a retracted position in which the second end of the cartridge is disposed within the barrel. Means prevents the cap from being removed from the barrel. 
     An advantage of the present invention is that the two-piece construction provides inexpensive component costs and assembly methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a side view of one embodiment of a pen of the present invention in an extended position; 
         FIG. 2  is a side cross-sectional view of the pen of  FIG. 1  taken along line  2 - 2 ; 
         FIG. 3  is a side view of the pen of  FIG. 1  in a retracted position; 
         FIG. 4  is a side cross-sectional view of the pen of  FIG. 3  taken along line  4 - 4 ; 
         FIG. 5  is a side view of the barrel of the pen of  FIG. 1 ; 
         FIG. 6  is a front cross-sectional view of the barrel of  FIG. 5  along line  6 - 6 ; 
         FIG. 7  is a fragmentary perspective view of the rear end of the barrel of  FIG. 5 ; 
         FIG. 8  is a cross-sectional view of the barrel of  FIG. 5  along line  8 - 8 ; 
         FIG. 9  is a rear view of the barrel of  FIG. 5  along line  9 - 9 ; 
         FIG. 10  is a fragmentary cross-sectional view of the threads of the barrel of  FIG. 6 ; 
         FIG. 11  is a view of the cap along line  11 - 11  of  FIG. 3 ; 
         FIG. 12  is a view of the cap along line  12 - 12  of  FIG. 11 ; 
         FIG. 13  is a cross-sectional view of the cap along line  13 - 13  of  FIG. 11 ; 
         FIG. 14  is an end view of the cap along line  14 - 14  of  FIG. 12 ; 
         FIG. 15  is a cross-sectional view of the cap along line  15 - 15  of  FIG. 12 ; and 
         FIG. 16  is an enlarged view of area  16  in  FIG. 13 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. Although the exemplification set out herein illustrates embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed. 
     DETAILED DESCRIPTION 
     The embodiments hereinafter disclosed are not intended to be exhaustive or limit the invention to the precise forms disclosed in the following description. Rather the embodiments are chosen and described so that others skilled in the art may utilize its teachings. 
     Referring to the drawings, wherein like numerals indicate like elements,  FIG. 1  shows one embodiment of a pen  20  of the present invention. Pen  20  includes a two-piece body  22 , having a barrel  24  and a cap  26  which is threadedly coupled to barrel  24 . Barrel  24  includes a smooth, continuous and annular imprint area  28  on which logos and/or lettering may be printed. However, it is also possible for the portion of barrel  24  including imprint area  28  to have a polygonal cross section. For example, the portion of barrel  24  including imprint area  28  may have a triangular cross section, thereby providing a flat imprint area on which logos and/or lettering may be printed. 
       FIG. 2  illustrates a cross-sectional view of pen  20  along line  2 - 2 . An ink cartridge  30  is held firmly in, and is fixedly attached to, cap  26 . The cap  26  defines an interior space or recess  27 , located inside the cap  26 . An interior surface  32  of cap  26  is threaded, and an exterior surface  34  of barrel  24  is correspondingly threaded and received in the recess  27  such that the threads of the interior surface  32  and the threads of the exterior surface  34  are in threaded engagement with each other. The threads on both surfaces  32 ,  34  may be male. That is, the threads may extend radially outward from surfaces  32 ,  34 . The mating threads on surfaces  32 ,  34  enable barrel  24  to be screwed inside cap  26 . More particularly, barrel  24  and cap  26  may be rotated relative to each other about an imaginary longitudinal axis  35  that is approximately defined by cartridge  30 . As barrel  24  is screwed in and out of cap  26  in directions indicated by double arrow  36 , pen  20  is moved between an extended position shown in  FIGS. 1 and 2  and a retracted position shown in  FIGS. 3 and 4 . In the extended position, a tip  38  of ink cartridge  30  projects through a through hole  40  in the distal end of barrel  24 . Through hole  40  may have a diameter about 1 millimeter larger than the diameter of the portion of cartridge  30  that extends through through hole  40 . Thus, cartridge  30  may move freely through through hole  40 , but the lateral movement or sway of cartridge  30  may be effectively limited by through hole  40 . A distance  42  that tip  38  extends beyond barrel  24  may be approximately between 0.10 and 0.16 inch in one embodiment. A length  44  between the distal tip of barrel  24  and a distal end of cap  26  in the extended position of  FIGS. 1 and 2  may be approximately between 5.38 and 5.58 inch in one embodiment. Cap  26  may include a conventional clip  46 . 
     As shown in  FIG. 3 , cap  26  includes a smooth, continuous and annular imprint area  48  on which logos and/or lettering may be printed. However, it is also possible for the portion of cap  26  including imprint area  48  to have a polygonal cross section. For example, the portion of cap  26  including imprint area  48  may have a triangular cross section, thereby providing a flat imprint area on which logos and/or lettering may be printed. A length  50  ( FIG. 4 ) between the distal tip of barrel  24  and a distal end of cap  26  in the retracted position of  FIGS. 3 and 4  may be approximately between 5.52 and 5.72 inch in one embodiment. 
     As shown in  FIG. 5 , barrel  24  may include threads in the form of, for example, four leads  52 , each of which extends about 360 degrees around barrel  24  over a length  54  of about 0.4 inch. Two rings  56 ,  58  are disposed on opposite sides of leads  52 . In one embodiment, rings  56 ,  58  are separated by a distance  60  of about 0.76 inch. Rings  56 ,  58  include are attached to each other by two opposing flats or a bars  62  which hold rings  56 ,  58  in fixed position relative to each other and which are in diametrically opposed positions on barrel  24 . A diameter  64  of barrel  24  may be about 0.376 inch, and a diameter of each of rings  56 ,  58  may be about 0.386 inch. Attached to and adjacent to ring  56  is an annular shoulder  66  having an intermediate diameter between the diameter of barrel  24  and the diameter of rings  56 ,  58 . For example, the diameter of should  66  may be about 0.380 inch. A distance  68  between ring  56  and an end of leads  52  may be about 0.200 inch. 
     A wall thickness  70  ( FIG. 6 ) of barrel  24  may be about 0.030 inch. As best shown in  FIG. 6 , barrel  24  includes a through channel  35  between two opposite open ends. Cartridge  30  may extend through through channel  35 , and, in the extended position, may extend through both of the two opposite open ends of barrel  24 . 
     An enlarged cross-sectional view of leads  52  is shown in  FIG. 10 . An angle of slope  72  of leads  52  may be about 20 degrees. A height  74  of leads  52  may be about 0.005 inch. A width  76  of leads  52  may be about 0.010 inch. A distance  78  between leads  52  may be about 0.013 inch. 
     As shown in  FIG. 12 , a width  80  of cap  26  may be about 0.465 inch. A length  82  of cap  26  may be about 2.125 inch. As shown in  FIG. 13 , annular interior surface  32  of cap  26  may include threads in the form of, for example, four leads  84 , each of which extends about 360 degrees around annular interior surface  32 . The combination of four leads  84  spans a length  86  of about 0.510 inch. A pitch of leads  84  may be about 0.4 inch, just as with leads  52 . A distance  88  between an open end  90  of cap  26  and an end of leads  84  may be about 0.230 inch. An inner diameter  92  of cap  26  may be about 0.390 inch. 
     An enlarged cross-sectional view of leads  84  is shown in  FIG. 16 . An angle of slope  94  of leads  84  may be about 20 degrees. A height  96  of leads  84  may be about 0.005 inch. A width  98  of leads  84  may be about 0.013 inch. A distance  100  between leads  84  may be about 0.010 inch. 
     During assembly, barrel  24  and cap  26  may be pushed together without the need for rotation or axial alignment. During use, ring  58  may abut against or engage one end of leads  84  of cap  26  in the extreme retracted position of pen  20  to thereby prevent cap  26  from separating from barrel  24 . Similarly, shoulder  66  and ring  56  may abut against or engage the other end of leads  84  of cap  26  in the extreme extended position of pen  20  to thereby prevent cartridge  30  from extending too far out from barrel  24 . 
     In one embodiment, a distance of travel of cap  26  and cartridge  30  relative to barrel  24  between the retracted and extended positions may be about 0.133 inch. This travel distance of 0.133 inch may correspond to a rotation of about 120 degrees, or one-third of a rotation, of cap  26  relative to barrel  24 , assuming a 0.4 inch pitch of the threads per rotation. 
     While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.