Patent Publication Number: US-6981812-B1

Title: Opening and closing device for capless retractable marker pen

Description:
RELATED APPLICATIONS 
   The present application is based on, and claims priority from, Taiwan Application Serial Number 94105692, filed Feb. 24, 2005, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   FIELD OF THE INVENTION 
   The present invention relates to an opening and closing device for a capless retractable marker pen, and more particularly, to an opening and closing device based on a two-stage design for a capless retractable marker pen. 
   BACKGROUND OF THE INVENTION 
   According to different inks used, ordinary marker pens can roughly be categorized as water-based marker pens and oil-based marker pens. In order to prevent a writing tip from becoming dried out and thus unusable from long-term exposure to air, an outer cap is usually used to seal the writing tip of the marker pen. However, two hands are required to uncap and cap a marker pen with the outer cap, which is very inconvenient. Furthermore, when capping or uncapping the writing tip, the outer cap can be easily lost along with any hope of preventing the writing tip from drying out. In order to resolve these issues related to using the outer cap, a capless retractable marker pen has been developed. Typically, the cover of the capless retractable marker pen is hidden within the pen tube, and the protracting and retracting of the writing tip is controlled by an actuating means installed in the top of the pen tube. Therefore, compared with the marker pen with an outer cap, the capless retractable marker pen has a superior competitive advantage on the market. 
     FIG. 1  illustrates a partial cross section showing a conventional capless retractable marker pen. The conventional capless retractable marker pen  100  comprises a pen tube  110 , a sheath  120 , a writing member  130  and an opening and closing device  140 . The pen tube  110  has an upper opening (not shown) and a lower opening  113 , in which an arc protrusion  115  is set within the pen tube  110 , and is parallel to the lower opening  113  and set apart from the lower opening  113  by a distance L. The sheath  120  is installed within the pen tube  110  and has an upper portion  121  and a lower portion  123 , in which a diameter D of the upper portion  121  is greater than a diameter d of the lower portion  123 . The top of the upper portion  121  is a closed end (not shown), and the bottom of the lower portion  123  is an open end  127 . Typically, the writing member  130  is coaxially disposed within the sheath  120  and has an upper portion  131  and a lower portion  133 . The upper portion  131  of the writing member  130  is disposed within the upper portion  121  of the sheath  120  for absorbing and storing ink. The lower portion  133  of the writing member  130  is disposed within the lower portion  123  of the sheath  120 , in which a portion of the lower portion  133  extends into the upper portion  121 . The lower portion  133  of the writing member  130  extends out of the open end  127  in the lower portion  123  of the sheath  120  to expose a writing tip  135 . The ink is transported from the upper portion  131  to the writing tip  135  through the lower portion  133  by capillarity. 
   In the conventional capless retractable marker pen designs, various opening and closing devices are used to replace the outer cap for achieving the purpose of protracting and retracting a writing tip. For example, the opening and closing device  140  comprises a supporting device  141 , a sealing member  161 , a plastic filament  169  and a spring member  170 . Referring to  FIG. 2 , which is a three-dimensional diagram of a conventional opening and closing device, the supporting device  141  is installed outside the lower portion  123  of the sheath  120 . The supporting device  141  has an upper opening  143  and a lower opening  145 , and a sidewall  147  of the supporting device  141  is set with two opposite grooves  149  extending from the upper opening  143 . The sealing member  161  covers the writing tip (not shown) and includes a cover plate  163  and a cover supporting tube  165 , and a side  164  of the cover plate  163  is movably deposed on a side  166  of the cover supporting tube  165 . A sidewall of the cover supporting tube  165  is set with two opposite channels  167 . The plastic filament  169  passes and is deposed in the grooves  149  of the supporting device  141 , the cover plate  163  and the channels  167 , and is clipped into the channels  167 . A spring  170  is coaxially deposed outside the lower portion  123  of the sheath  120  and within the supporting device  141 . The spring  170  shores the supporting device  141  and the cover supporting tube  165  by elastic force and tightly buckles the supporting device  141  and the sealing member  161  by the plastic filament  169 , so as to make the cover plate  163  cover a lower surface  168  of the cover supporting tube  165  to seal the writing tip (not shown). 
     FIG. 3(A)  illustrates an opening action of a cover plate of an opening and closing device of a conventional capless retractable marker pen. When the sheath  120  and the writing tip  135  are moved downward by using an actuating means (not shown) installed on the top of the sheath  120 , the opening and closing device  140  descends to the arc protrusion  115  in the pen tube  110  along the direction shown by an arrow  171 , and the sealing member  161  continuously rises along the direction shown by the arrow  171  to make the plastic filament  169  loosened gradually. The cover plate  163  is opened resulting from the loosening of the plastic filament  169 , so as to make the writing tip  135  project from the cover supporting tube  165  for writing. 
     FIG. 3(B)  illustrates a closing action of a cover plate of an opening and closing device of a conventional capless retractable marker pen. After writing, the sheath  120  and the writing tip  135  are moved upwardly by using the actuating means (not shown), the supporting device  141  continuously rises along the direction shown by an arrow  173 , and the sealing member  161  descends relatively to make the plastic filament  169  tighten gradually, so that the lower surface  168  of the cover supporting tube  165  is covered by the cover plate  163  to seal the writing tip  135 . In brief, the opening and closing device for the conventional capless retractable marker pen is based on a two-stage design, which combines the supporting device  141 , the sealing member  161 , the plastic filament  169  and the spring  170 , for achieving the purpose of protracting and retracting the writing tip. 
   The examples that use any of the various opening and closing devices, such as the disclosure in Taiwan patent No. 341,920, the disclosure in U.S. Pat. No. 4,969,764 and the disclosure in U.S. Pat. No. 4,560,298, are hereby incorporated by reference herein in their entirety. 
   However, the conventional capless retractable marker pens still have many problems requiring solving. The assembling of the opening and closing device of the conventional capless retractable marker pens is done by hand to put the plastic filament  169  on the grooves  149  of the supporting device  141 , the cover plate  163  and the channels  167 , so that the assembling process is complicated, time-consuming, and the difficult to be sped up in mass production. Furthermore, the opening and closing effect of the opening and closing device is degraded by the elastic fatigue of the plastic filament  169  after being used for a period of time. 
   It would therefore be desirable for the designers, the users and the manufacturers of pens to improve the structure of the conventional opening and closing device to simplify the manufacture and assembly and thereby increase the manufacturing speed and the yield. 
   SUMMARY OF THE INVENTION 
   One objective of the present invention is to provide an opening and closing device for a capless retractable marker pen, which is based on a two-stage design for achieving the purpose of protracting and retracting a writing tip. The opening and closing device for the capless retractable marker pen of the present invention allows for easy manufacture and convenient assembly, so that an automation process can be used to greatly increase the processing speed and yield. 
   According to the aforementioned objectives, the present invention provides an opening and closing device for a capless retractable marker pen, comprising a supporting device, a cover holder, a sealing member and a spring member. The supporting device has an upper opening and a lower opening, wherein a plurality of hooks are disposed around the lower opening, and a protrusion is deposed in a substantially central portion of an outer surface of each hook. The cover holder has an upper ring, a plurality of supports connected to the upper ring and a lower ring connected to the supports, wherein the upper ring is coaxially disposed outside the supporting device and clipped between a rear end of each hook and each protrusion. The sealing member is coaxially clipped within the lower ring of the cover holder and covers a writing tip disposed in the supporting device and the cover holder, wherein the sealing member includes a cover plate and a cover supporting tube, and a side of the cover plate is movably deposed on a side of the lower ring. The spring member is coaxially disposed within the supporting device, wherein the spring member shores the supporting device and the cover supporting tube by elastic force, so as to make the cover plate cover a lower surface of the cover supporting tube to seal the writing tip. When the writing tip moves downward, the opening and closing device descends to an arc protrusion in the pen tube, and the cover holder continuously rises across the protrusions of the supporting device to reach the outside of the upper opening of the supporting device, wherein with the rise of the cover holder, the cover plate is opened to make the writing tip project from the cover supporting tube. 
   According to a preferred embodiment of the present invention, the supporting device and the cover holder may be composed of the same thermoplastic material or different thermoplastic materials. 
   According to the aforementioned objectives, the present invention further provides a capless retractable marker pen comprising a pen tube, a sheath, a writing member and an opening and closing device. The pen tube has a first upper opening and a first lower opening, wherein an arc protrusion is set within the pen tube, is parallel to the first lower opening and is set apart from the first lower opening by a distance. The sheath has a first upper portion and a first lower portion, wherein a diameter of the first upper portion is greater than a diameter of the first lower portion. The writing member is coaxially disposed within the sheath and has a second upper portion and a second lower portion, wherein the second upper portion is disposed within the first upper portion for storing ink, the second lower portion is disposed within the first lower portion to expose a writing tip, and a diameter of the second lower portion is smaller than a diameter of the second upper portion. The opening and closing device comprises a supporting device, a cover holder, a sealing member and a spring member. The supporting device is coaxially disposed outside the first lower portion of the sheath and has a second upper opening and a second lower opening, wherein a plurality of hooks are disposed around the second lower opening, and a protrusion is deposed in a substantially central portion of an outer surface of each hook. The cover holder has an upper ring, a plurality of supports connected to the upper ring, and a lower ring connected to the supports, wherein the upper ring is coaxially disposed outside the supporting device and clipped between a rear end of each hook and each protrusion. The sealing member is coaxially clipped within the lower ring and covers the writing tip, wherein the sealing member includes a cover plate and a cover supporting tube, and a side of the cover plate is movably deposed on a side of the lower ring. The spring member is coaxially disposed outside the first lower portion of the sheath and within the supporting device, wherein the spring member shores the supporting device and the cover supporting tube by elastic force, so as to make the cover plate cover a lower surface of the cover supporting tube to seal the writing tip. When the sheath moves downward, the opening and closing device descends to the arc protrusion in the pen tube, and the cover holder continuously rises across the protrusions of the supporting device to reach the outside of the second upper opening of the supporting device, wherein with the rise of the cover holder, the cover plate is opened to make the writing tip project from the cover supporting tube. 
   According to a preferred embodiment of the present invention, the ink may be, for example, water-based ink or oil-based ink. 
   In the application of the opening and closing device for the capless retractable marker pen, the opening and closing device is based on a two-stage design for achieving the purpose of protracting and retracting a writing tip, and allows for easy manufacture and convenient assembly, so that an automation process can be used to greatly increase the process speed and yield. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  illustrates a partial cross section showing a conventional capless retractable marker pen; 
       FIG. 2  illustrates a three-dimensional diagram of a conventional opening and closing device; 
       FIG. 3(A)  illustrates an opening action of a cover plate of an opening and closing device of a conventional capless retractable marker pen; 
       FIG. 3(B)  illustrates a closing action of a cover plate of an opening and closing device of a conventional capless retractable marker pen; 
       FIG. 4  illustrates a partial cross section showing a capless retractable marker pen in accordance with a preferred embodiment of the present invention; 
       FIG. 5  illustrates a three-dimensional diagram of an opening and closing device in accordance with a preferred embodiment of the present invention; 
       FIG. 6(A)  illustrates an opening action of a cover plate of an opening and closing device of a capless retractable marker pen in accordance with a preferred embodiment of the present invention; and 
       FIG. 6(B)  illustrates a closing action of a cover plate of an opening and closing device of a capless retractable marker pen in accordance with a preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The opening and closing device for a capless retractable marker pen of the present invention is based on a two-stage design for achieving the purpose of protracting and retracting a writing tip. In order to make the illustration of the present invention more explicit and complete, the following description is stated with reference to  FIGS. 4 through 6(B)   
     FIG. 4  is a partial cross section showing a capless retractable marker pen in accordance with a preferred embodiment of the present invention. A capless retractable marker pen  200  of the present invention comprises a pen tube  210 , a sheath  220 , a writing member  230  and an opening and closing device  240 . The pen tube  210  has an upper opening (not shown) and a lower opening  213 , in which an arc protrusion  215  is set within the pen tube  210 , is parallel to the lower opening  213 , and is set apart from the lower opening  213  by a distance L 1 . The sheath  220  is installed within the pen tube  210  and has an upper portion  221  and a lower portion  223 , in which a diameter D 1  of the upper portion  221  is greater than a diameter D 2  of the lower portion  223 . The top of the upper portion  221  is a closed end (not shown), and the bottom of the lower portion  223  is an open end  227 . Typically, the writing member  230  is coaxially disposed within the sheath  220  and has an upper portion  231  and a lower portion  233 . The upper portion  231  of the writing member  230  is disposed within the upper portion  221  of the sheath  220  and is composed of a liquid-absorbing wick for the storage of ink. The ink may be, for example, water-based ink, oil-based ink or organic-solvent-based ink, in which the organic-solvent-based ink may be, for example, alcohol-based ink. The lower portion  233  of the writing member  230  is disposed within the lower portion  223  of the sheath  220 , in which a portion of the lower portion  233  extends into the upper portion  221 . The writing member  230  is composed of a porous fibrous material. The lower portion  233  of the writing member  230  extends out of the open end  227  in the lower portion  223  of the sheath  220  to expose a writing tip  235 . The ink is transported from the upper portion  231  to the writing tip  235  through the lower portion  233  by capillarity. 
   One feature of the capless retractable marker pen of the present invention is that it is based on a two-stage design for achieving the purpose of protracting and retracting a writing tip. As shown in  FIG. 4 , the opening and closing device  240  is coaxially disposed outside the lower portion  223  of the sheath  220 , in which the opening and closing device  240  comprises a supporting device  241 , a cover holder  251 , a sealing member  261  and a spring member  270 . 
     FIG. 5  illustrates a three-dimensional diagram of an opening and closing device in accordance with a preferred embodiment of the present invention. In an embodiment, the supporting device  241  is coaxially disposed outside the lower portion  223  of the sheath  220 , in which the supporting device  241  has an upper opening  243  and a lower opening  245 . A plurality of hooks  247  are installed around the lower opening  245 , in which an outer surface  248  of each hook  247  has a protrusion  249  in its substantially central portion. The cover holder  251  has an upper ring  253 , a plurality of supports  255  connected to the upper ring  253 , and a lower ring  257  connected to the supports  255 , in which the upper ring  253  is coaxially disposed outside the supporting device  241  and clipped between a rear end  250  of each hook  247  and the protrusion  249 . The sealing member  261  is coaxially clipped within the lower ring  257  of the cover holder  251  and covers the writing tip (not shown). The sealing member  261  includes a cover plate  263  and a cover supporting tube  265 , and a side  264  of the cover plate  263  is movably deposed on a side  258  of the lower ring  257 . The spring member  270  may be, for example, a spring or a member having an equivalent function, and is coaxially disposed outside the lower portion  223  of the sheath  220  and within the supporting device  241 , in which the spring member  270  shores the supporting device  241  and the cover supporting tube  265  by elastic force, so as to make the cover plate  263  cover a lower surface  266  of the cover supporting tube  265  to seal the writing tip (not shown). 
   According to a preferred embodiment of the present invention, the supporting device  241  and the cover holder  251  may be composed of the same thermoplastic material or different thermoplastic materials. The thermoplastic material suitable for the supporting device  241  and the cover holder  251  typically includes but is not limited to polyformaldehyde (POM) and acrylonitrile butadiene styrene (ABS) copolymer. 
     FIG. 6(A)  illustrates an opening action of a cover plate of an opening and closing device of a capless retractable marker pen in accordance with a preferred embodiment of the present invention. When the sheath  220  and the writing tip  235  are moved downward by using an actuating means (not shown) installed on the top of the sheath  220  for example, the opening and closing device  240  descends to the arc protrusion  215  in the pen tube  210  along the direction shown by an arrow  271 , and the cover holder  251  continuously rises along the direction shown by the arrow  271  across the protrusion  249  of the supporting device  241  to reach the outside of the upper opening  243  of the supporting device  241 . With the rise of the cover holder  251 , the cover plate  263  is opened to make the writing tip  235  project from the cover supporting tube  265  for writing. 
     FIG. 6(B)  illustrates a closing action of a cover plate of an opening and closing device of a capless retractable marker pen in accordance with a preferred embodiment of the present invention. After writing, the sheath  220  and the writing tip  235  are moved upward by using the actuating means (not shown), the supporting device  241  continuously rises along the direction shown by an arrow  273 , and the cover holder  251  descends relatively across the protrusion  249  of the supporting device  241  to reach the rear end  250  of each hook  247  of the supporting device  241 , so that a lower surface  268  of the cover supporting tube  265  is covered by the cover plate  263  to seal the writing tip  235 . In brief, the opening and closing device for the capless retractable marker pen is based on a two-stage design, which combines the supporting device  241  and the cover holder  251 , for achieving the purpose of protracting and retracting the writing tip. 
   It is worthy to note that the opening and closing device for the capless retractable marker pen can replace the conventional opening and closing device, which uses the plastic filament to control the cover plate. In the present invention, the opening and closing device is based on a two-stage design for achieving the purpose of protracting and retracting the writing tip. The opening and closing device for the capless retractable marker pen of the present invention is manufactured easily and assembled conveniently, so that the complicated assembly of the conventional opening and closing device can be effectively improved, and an automation process can be used to greatly increase the processing speed and yield. 
   According to the aforementioned embodiments of the present invention, one advantage of the application of the opening and closing device for the capless retractable marker pen of the present invention is that the opening and closing device is based on a two-stage design for achieving the purpose of protracting and retracting a writing tip. The opening and closing device for the capless retractable marker pen of the present invention enables easy manufacture and convenient assembly, so as to greatly increase the processing speed and yield. 
   As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure.