Patent Publication Number: US-6341911-B1

Title: Writing instrument with adjustable shaft

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to a writing instrument with an adjustable shaft and, more specifically, to a writing instrument with a shaft that is originally in the shape of a cylinder and can be molded into an ergonomic shape when the pen point is retrieved for writing, providing a comfortable writing experience. 
     II. Description of the Prior Art 
     Heretofore, it is known to construct a writing instrument in the shape of a straight tube and made of hard plastic or metals. A writing instrument of such construction is not ergonomically designed and tends to generate uncomfortable feelings, especially when holders write for a relatively long period of time. 
     It is also known to construct a writing instrument of which the shape of the shaft is designed ergonomically. Nonetheless, the look of an ergonomically designed writing instrument may not be desirable to consumers. 
     The present invention improves on the heretofore known writing instrument by providing a pen shaft with variable shapes that offers extended writing comfort as well as stylish pen design. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the invention to provide a writing instrument having an ergonomically designed shaft with a graceful look. The shaft of the present invention is composed of a barrel, a grip and a head, fitted together by the threaded head. A switch that retrieves and retracts the pen point of the cartridge is installed in the barrel and is connected to a driver. The grip is covered with a soft rubber gripping section. 
     A few long and narrow holes are located at equal intervals inside the grip close to the threaded head. Near the lower end of the holes are ditches. Vertically positioned support rods are accommodated in the ditches outside the grip. The bottom of the support rods goes into the ditches, and the top of the support rods goes upwards through the holes and sticks out slightly into the threaded head reaching the driver. 
     As holders click or turn the button for the first time, the switch pushes the cartridge and the driver downwards, and in turn the driver pushes the support rods downwards, making the support rods bend and prop the soft rubber gripping section into the shape of an arch. To undo the action, holders click or turn the button again so that all the components go back to their original positions, and the shaft returns to the shape of a cylinder. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawing, in which: 
     FIG. 1 is a sectional view of the present invention; 
     FIG. 2 is a partial elevational view of a pen according to the present invention; 
     FIG. 3 shows one application of the present invention; 
     FIG. 4 is a lateral view of the present invention; 
     FIG. 5 is an enlarged view of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG.  1  and FIG. 5, the present invention comprises a barrel  10 , a grip  20 , a head  30 , a cartridge  60 , a button  40 , a switch  41 , a driver  50 , and a soft rubber gripping section  80 . 
     The barrel  10 , the grip  20  and the head  30  are connected together by threaded heads  11  ,  21  to form a pen shaft. The cartridge  60  is put inside the shaft, and the pen point of the cartridge  60  is capped with a spring. The grip  20  is covered with a soft rubber gripping section  80 , and the driver  50  is put below the switch  41  in the barrel  10 . 
     The switch  41  is installed within the barrel  10  near the end of the cartridge  60 , and the button  40  is set on the top of the switch  41 . When the button  40  is clicked or turned, the switch  41  pushes to retrieve or retract the pen point of the cartridge  60  from the shaft. 
     Refer to FIG.  2  and FIG. 5, a few long and narrow holes  22  are disposed at equal intervals inside the grip  20  close to the threaded head  11 ,  21 . Near the lower end of the holes  22  and outside the grip  20 , there are corresponding ditches  23 . A few support rods  70  are positioned vertically in ditches  23  outside the grip  20 , wherein, their lower ends protrude the ditches  23 , and reach the head  30 . The top of the support rods  70  goes through the holes  22  and sticks out slightly into the threaded head  21  under the driver  50 . 
     As can be seen in FIG.  1  and FIG. 3, as holders click or turn the button  40 , the switch  41  pushes the cartridge  60  and the driver  50 . In turn, the pen point of the cartridge  60  sticks out of the shaft, and the driver  50  pushes the support rods  70 , making the support rods  70  bend and prop the soft rubber gripping section  80  to form three ergonomic arches. When the button  40  is clicked or turned again, all the components go back to their original positions, and the shape of the shaft is molded back into a cylinder. 
     The present invention has the advantages of providing an adjustable profile of the pen shaft. When in use, the shaft is molded into an ergonomic shape when in use and returns to the shape of a cylinder when the pen point of the cartridge is retracted. 
     While a preferred embodiment of the invention has been shown and described in detail, it will be readily understood and appreciated that numerous omissions, changes and additions may be made without departing from the spirit and scope of the invention.