Abstract:
A writing instrument includes a travel multiplier mechanism that includes a cam member that pivots about a pivot axis in response to motion of a push button member. The cam member engages a sliding piston member in order to provide a travel multiplying effect such that a distance of travel of the sliding piston member exceeds a distance traveled by the push button member.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a divisional of U.S. patent application Ser. No. 11/346,137, filed Feb. 2, 2006 (now U.S. Pat. No. 7,891,897), which claims the benefit or priority of U.S. Provisional Patent Application No. 60/649,734, filed Feb. 3, 2005, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure is related generally to writing instruments, and more particularly to writing instruments having retractable writing tips. 
     BACKGROUND OF THE DISCLOSURE 
     Writing instruments have been developed that are capable of being put in either a retracted or an extended configuration, as desired by the user. 
     A typical writing instrument of such type may include a barrel with a clip, an ink cartridge arranged within the barrel and having a writing tip, a push button, and a mechanism providing extending and retracting movement of the ink cartridge out of the barrel, and maintaining the ink cartridge in a writing position. The mechanism may include a push button, a ratchet, and a return spring. 
     However, for certain writing instruments, such as, for example, fountain pens, highlighters or other types of markers having felt tips, moving a writing tip from an extended position to a retracted position and vice versa may require a large amount of travel, making a mechanism for extending and retracting the writing tip cumbersome, difficult to use, and bulky. 
     The present disclosure is directed to solving one or more of the problems associated with the prior art. 
     SUMMARY OF THE DISCLOSURE 
     In accordance with one aspect of the disclosure, a writing instrument includes a travel multiplier mechanism that includes a cam member that pivots about a pivot axis in response to motion of a push button member. The cam member engages a sliding piston member in order to provide a travel multiplying effect such that a distance of travel of the sliding piston member exceeds a distance traveled by the push button member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic partial cross-sectional view of a writing instrument according to a first embodiment of the disclosure, in a retracted configuration; 
         FIG. 2  is a schematic partial cross-sectional view of the writing instrument of  FIG. 1 , in an extended configuration; 
         FIG. 3  is a side view of a writing instrument according to a second embodiment of the disclosure; 
         FIG. 4  is an enlarged side view of an upper portion of the writing instrument of  FIG. 3 ; 
         FIG. 5  is an enlarged perspective view of a portion of a travel multiplier mechanism forming part of the writing instrument of  FIG. 3 ; 
         FIG. 6  is a cutaway perspective view of a third embodiment of a writing instrument according to the disclosure in a retracted configuration; 
         FIG. 7  is a cutaway perspective view of the writing instrument of  FIG. 6  in an extended configuration; 
         FIG. 8  is an exploded view of components of the writing instrument of  FIG. 6 ; 
         FIG. 9  is a partial cross-sectional view of an upper portion of a fourth embodiment of a writing instrument according to the disclosure in a retracted configuration; 
         FIG. 10  is a partial cross-sectional view of the upper portion of the writing instrument of  FIG. 9  in a partially extended configuration; 
         FIG. 11  is a partial cross-sectional view of the upper portion of the writing instrument of  FIG. 9  in a fully extended configuration; 
         FIG. 12  is a side view of a writing instrument according to a fifth embodiment of the disclosure; 
         FIG. 13  is a front view of the writing instrument of  FIG. 12 ; 
         FIG. 14  is a partial cross-sectional view of an upper portion of the writing instrument of  FIG. 12 , taken along lines  14 - 14  of  FIG. 13 ; 
         FIG. 15  is a cross-sectional view of the writing instrument of  FIG. 12 , taken along lines  15 - 15  of  FIG. 14 ; 
         FIG. 16  is across-sectional view of the writing instrument of  FIG. 12 , taken along lines  16 - 16  of  FIG. 14 ; 
         FIG. 17  is a cross-sectional view of the writing instrument of  FIG. 12 , taken along lines  17 - 17  of  FIG. 14 ; and 
         FIG. 18  is a cross-sectional view of the writing instrument of  FIG. 12 , taken along lines  18 - 18  of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference initially to  FIG. 1 , a first embodiment of the disclosure includes a writing instrument  10  having a travel multiplier mechanism, generally indicated at  12 . The travel multiplier mechanism  12  includes a push button member  14 , that abuts a sliding and rotating cam member  16  that is pivotally engaged within opposing slots  18  formed in a wall  20  of the writing instrument  10 . The sliding and rotating cam member  16  also includes a tip  17  that abuts a sliding piston member  22  that is disposed within the wall  20 . The sliding piston member  22  may include a protuberance  24  that, along with the wall  20  and the slots  18 , serves to constrain the motion of the sliding and rotating cam member  16  as the push button member  14  is moved from an extended position, as shown in  FIG. 1 , to a retracted position, as shown in  FIG. 2 . 
     As can be seen by an examination of  FIGS. 1 and 2 , the slots  18  may be disposed at a diagonal orientation so that the sliding and rotating cam member  16  moves from a substantially horizontal orientation when the push button member  14  is in the extended position, as shown in  FIG. 1 , to a substantially vertical orientation when the push button member  14  is in the retracted position, having moved a distance of travel, a, as shown in  FIG. 2 . This rotation of the sliding and rotating cam member  16 , as well as the translation thereof in a generally vertical direction as oriented in  FIG. 2 , serves to provide a distance of travel, b, of the tip  17  of the sliding and rotating cam member  16  and of the sliding piston member  22  that exceeds the distance of travel, a, of the push button member  14  between the retracted position and the extended position. 
     As will be recognized by those of skill in the art, the additional distance of travel of the tip  17  of the sliding and rotating cam member  16  as compared to the distance of travel of the push button member  14  is advantageous for any writing instrument or other apparatus that requires an extension/retraction mechanism providing a large travel distance of a component such as a writing instrument tip, while minimizing the travel distance of an actuating mechanism such as a push button member, while minimizing the amount of space required for such an apparatus. For example, it is envisioned that the travel multiplication mechanism shown in  FIGS. 1 and 2  would be especially useful for a retractable felt-tip marker that requires a large amount of travel to expose the tip of the marker, without requiring a very long, cumbersome, and unattractive push button member. 
       FIG. 3  is a side view of another embodiment of a writing instrument  10 ′ having a mechanism similar to that of the writing instrument  10  depicted in  FIGS. 1 and 2 . As shown in  FIG. 4 , the writing instrument  10 ′ includes a travel multiplier mechanism, generally indicated at  12 ′. The travel multiplier mechanism  12 ′ includes a push button  14 ′, that abuts a sliding and rotating cam member  16 ′ that is pivotally engaged within opposing slots  18 ′ formed in a wall  20 ′ of the writing instrument  10 ′. The sliding and rotating cam member  16 ′ also includes a tip  17 ′ that abuts a ratchet member  23 ′ that is disposed within the wall  20 ′. The ratchet member  23 ′ includes a cylindrical protuberance  24 ′ that, along with the all  20 ′ and the slots  18 ′, serves to constrain the motion of the sliding and rotating cam members  16 ′ as the push button member  14 ′ is moved from an extended position to a retracted position. A pair of flanges  25 A′ and  25 B′ are provided on the ratchet member  23 ′, and engage vertical slots  27 A′ and  27 B′ formed in the wall  20  to prevent rotation of the ratchet member  23 ′. 
     The slots  18 ′ may be disposed at a diagonal orientation so that the sliding and rotating cam member  16 ′ moves from a substantially horizontal orientation when the push button member  14 ′ is in the extended position, to a substantially vertical orientation when the push button member  14 ′ is in the retracted position. As was the case with the embodiment of  FIGS. 1 and 2 , the rotation of the sliding and rotating cam member  16 ′, as well as the translation thereof in a generally vertical direction as oriented in  FIGS. 3-5  serves to provide a distance of travel of the tip  17 ′ of the sliding and rotating cam member  16 ′ and of the ratchet member  23 ′ that exceeds the distance of travel of the push button member  14 ′ between the retracted position and the extended position. 
     Again, the additional distance of travel of the tip  17 ′ of the sliding and rotating cam member  16 ′ as compared to the distance of travel of the push button member  14 ′ is advantageous for any writing instrument or other apparatus that requires an extension/retraction mechanism providing a large distance of travel of a component such as a writing instrument, while minimizing the travel distance of an actuating mechanism such as a push button member, and while minimizing the amount of space required for such an apparatus. 
     With reference now to  FIGS. 6-8  a further embodiment is provided, in the form of a writing instrument  110  that includes a travel multiplier mechanism, generally indicated at  112 . The travel multiplier mechanism  112  includes a push button  114 , that abuts a first sliding cam member  116  that in turn engages a helical slot  118  of an inner barrel  120  of the writing instrument  110 . (The writing instrument  110  may include an outer barrel, not shown in  FIGS. 6-8  for clarity.) A second sliding cam member  122  engages a pair of straight slots  124  formed in opposing sides of the inner barrel  120 . The first sliding cam member  116  may include first and second protuberances  126 ,  128 , that may be disposed on opposite sides of the first sliding cam member  116 . The first and second protuberances  126  and  128  may each include an angled surface  130 ,  132 , respectively, that matches the contour of the helical slot  118  when the first sliding cam member  116  is disposed partially within the inner barrel  120 . Similarly, the second sliding cam member  122  may include first and second straight protuberances  134 ,  136 , that engage the straight slots  124  formed in the inner barrel  20  when the second sliding cam member  122  is disposed within the inner barrel  120 . 
     The first sliding cam member  116  and the second sliding cam member  122  may each have opposed angled faces,  138 ,  140 . 
     A spring  142  may be provided to urge the second sliding cam member  122 , the first sliding cam member  116 , and the push button  114  toward a position in which the push button  114  is extended, thereby placing a writing tip  144  in a retracted position within an outer barrel (not shown in  FIGS. 6-8 ). 
     In operation, as the push button  114  is pressed to place the push button  114  in a retracted position, and in turn place the writing tip  144  in an extended position, the first sliding cam member  116 , as it is pushed by the push button  114 , will translate in a direction along a primary axis  146  of the writing instrument  110 , and will also rotate about the primary axis  146 , due to the interaction of the angled surfaces  130  and  132  with the helical slot  118 . The rotation and translation of the first sliding cam member  116  causes the second sliding cam member  122  to translate (as the second sliding cam member  122  is constrained from rotation by the engagement of the first and second straight protuberances  134  and  136  with the straight slots  124 ) over a distance that exceeds the distance of translation of the push button  114  and the first sliding cam member  116 . 
     The push button  114  may be formed such that it fits over a round cylindrical protrusion  148  of the first sliding cam member  116  (shown in  FIG. 8 ), such that the push button  114  and the first sliding cam member  116  are free to rotate with respect to one another about the primary axis  146 . When the writing tip  144  is in the retracted position, as shown in  FIG. 6 , angled contact surfaces  150  and  152  of the first sliding cam member  116  and the second sliding cam member  122 , respectively, are in position such that the angled contact surfaces  150  and  152  are in substantially complete overlapping contact with one another and are substantially parallel to one another. This provides a compact configuration when the writing tip  144  is in the retracted position. 
     However, when the writing tip  144  is in the ex ended position, as shown in  FIG. 7 , the angled contact surfaces  150  and  152  contact one another at outermost apex regions  154  and  156  of the angled surfaces  150  and  152 , respectively, thereby providing a maximum extended position of the writing tip  144 . 
     With reference now to  FIGS. 9-11 , another embodiment is shown, in the form of a writing instrument  210  that includes a travel multiplier mechanism, generally shown at  212 . The travel multiplier mechanism  212  includes a push button  214  that abuts a rotating cam member  216  that may be pivotally secured to a clip member  218  of the writing instrument  210 . An end portion  220  of the rotating cam member  216  engages an angled surface  222  of a sliding piston member  224  that is disposed with a barrel  226  of the writing instrument  210 . 
       FIG. 10  is a schematic diagram showing the respective positions of the push button member  214 , the rotating cam member  216 , and the sliding piston member  224  in an intermediate position when the push button member  214  is between the extended position shown in  FIG. 9  and the retracted position shown in  FIG. 11 . 
     Yet another embodiment of the writing instrument  210  is shown in  FIGS. 12-18 . The rotating cam member  216  is installed with possibility of rotation about an axis  246  ( FIG. 18 ) located in a plane perpendicular to a primary axis  228  ( FIG. 12 ) of the barrel. As shown in  FIGS. 14-18  the rotating cam member  216  may be disposed between the push button  214  and a ratchet system  230 , and may have profiled surface that contacts respectively with a lower surface of the push button  214  and an upper ratchet member  236 , so that the push button and the upper ratchet member  236  form driving and receiving components of the travel multiplier mechanism  212 , respectively. 
     The barrel  226  may include upper and lower parts  226   a ,  226   b  ( FIGS. 12 and 13 ). The push button  214  may be installed inside of the upper part  226   a  of the barrel  226  with possibility of linear movement along the primary axis  228  of the barrel  226 . A replaceable ink cartridge  232  may be disposed in the barrel  226  and biased toward the upper part of the barrel  226  by a coiled spring (not shown at the drawing), disposed inside of the lower end barrel  226   b . The upper end of the ink cartridge  232  may be engaged with a lower ratchet  234 , which may engage the upper ratchet  236  maintaining the ink cartridge  232  in an extended writing position at the end of the extending movement, and releasing the ink cartridge  232  at the start of retraction. The lower ratchet  234  may include a sleeve portion  235  and the upper ratchet  236  may include a post portion  237  that engages the sleeve portion  235 . A clip  238  may be manufactured as an integrated part of the barrel  226 , or as a separate element. The clip  238  may include a cavity  240  with a cylindrical portion  242 , which supports a cylindrical part  244  of the rotating cam member  216 . The cylindrical part  244  of the rotating cam member  216  may be installed between a side surface of the barrel and inside of the cylindrical portion  242 , forming a rotational joint with fixed axis  246  ( FIG. 18 ) of rotation. A slot  248  formed in the upper part  226   a  of the barrel, provides possibility of rotation of the rotating cam member  216 . 
     The push button  214  and the upper ratchet  236  have slots  250  and  252 , respectively, of the same width. The slots  250  and  252  facilitate installation and free rotation of the rotating cam member  216 . The rotating cam member  216  may be installed inside of the slots, and inside of the cavity  240  with possibility of rotation around the axis  246  of the cylindrical portion  242  of the cavity  240 , so that the profiled surface of the rotating cam member  216  contacts with profiled surfaces  254  and  256 , of the push button  214  and the upper ratchet  236 , respectively. Protrusions  258  ( FIG. 17 ) may be provided at the inside surface of the upper end  226   a  of the barrel  226  to form a guide system for the linear movement of the ratchets  234  and  236 . 
     When pressed down, the push button  214  transfers force to the surface of the rotating cam member  216  causing the rotation of the rotating cam member  216  around the axis  246  of the cylindrical portion  242  of the cavity  240 . Because the rotating cam member  216  is in constant contact with the surface of the upper ratchet  236 , rotation of the rotating cam member  216  results in linear movement of the upper ratchet  236 , which thereby serves as a sliding piston member inside of the barrel  226 . The movement of the upper ratchet  236  through the lower ratchet  234  is transferred to the ink cartridge  232 . As a result, because of the cam rotation and its profile, the linear movement of the push button  214  is amplified mechanically. 
     When the push button  24  is pressed, the movement of the push button  214  down initiates rotation of the rotating cam member  216 , which in turn initiates linear movement of the ratchets  234  and  236  and extension of the ink cartridge  232 . Upward movement of the ratchets  234  and  236  at the time of the retraction of the ink cartridge  232  initiates rotation of the rotating cam member  216  in the opposite direction and movement of the push button  214  upward. The profile and rotation of the rotating cam member  216  provide transfer of the linear movement from the push button  214  to the upper ratchet  236  with displacement multiplication. The multiplication coefficient (transfer ratio) depends on the location of the cam rotational axis  246  (relatively to the primary axis  228  of the barrel  226 ), cam radius, and cam profile. In this embodiment shown in  FIGS. 12-18 , in which a cam rotational axis  246  was located outside of the surface of the barrel  226 , the transfer ratio was equal to about 1.9. 
     Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed herein.