Patent Publication Number: US-6213661-B1

Title: Retractable felt-tipped pen

Description:
This application claims benefit to U.S. provisional application Ser. No. 60/057,420, filed Sep. 3, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to writing implements, and more particularly to a felt-tipped writing implement such as a felt-tipped pen which has a self-sealing mechanism for enclosing the felt nib when not in use. 
     2. Description of the Related Art 
     Felt-tipped pens are well known in the art and typically include a felt nib connected to a reservoir of ink. Ink is supplied to the nib by capillary action and/or gravity. When the felt tipped pen is not in use, it is necessary for the pen to be sealed to prevent the ink from evaporating from the nib and to prevent the nib from contacting external surrounding surfaces, such as a desk or papers, and bleeding ink onto those surfaces. 
     Known felt-tipped pens are usually sealed using removable caps, which may be lost or misplaced. Alternatively, retractable felt-tipped pens have been designed, but these pens typically use very complex sealing mechanisms to seal the retracted pen nib in the pen body. Complex sealing mechanisms are undesirable since they are prone to failure. Further, the additional cost of manufacturing these complex mechanisms may require the retail sale price of the pens to be too high for the pen to compete in the marketplace. 
     Accordingly, it is an object of the invention to provide a retractable felt-tipped pen which is simple in construction and which may be manufactured in a cost-efficient manner. It is another object of this invention to provide a reliable retractable felt-tipped pen with a simple sealing mechanism which may reliably seal the pen nib within the pen body. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a retractable felt-tipped pen includes first and second cylindrical members movable with respect to each other and a nib connected to one of the first and second cylindrical members. A flexible membrane is disposed between the cylindrical members and rotates without substantial displacement to engage the pen nib in a closed condition to seal the pen nib in a closed condition and rotates without substantial displacement to expose the pen nib in a writing condition. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Certain illustrative embodiments of the present invention will now be described more specifically with reference to the attached drawings, wherein: 
     FIG. 1 is a side view, partially cut away, of one embodiment of the pen in a sealed condition; 
     FIG. 2 is a side view, partially cut away, of the pen of FIG. 1 in an open condition; 
     FIG. 3 is an enlarged, cross-sectional view, of the sealing mechanism of the pen of FIG. 1; 
     FIG. 4 is an enlarged, cross-sectional view, of the sealing mechanism of the pen of FIG. 2; 
     FIG. 5 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention using a retractable sleeve and a zero diameter neoprene tube in an open condition; 
     FIG. 6 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention using a retractable sleeve in a closed condition; 
     FIG. 7 is an enlarged, cross-sectional view, of the pen of FIG. 6 in a partially closed condition; 
     FIG. 8 is an enlarged, cross-sectional view, of the pen of FIG. 6 in an open condition; 
     FIG. 9 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention in a closed condition featuring an indented flexible membrane; 
     FIG. 10 is an enlarged, cross-sectional view, of the pen of FIG. 9 in an open condition; 
     FIG. 11 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention in a partially closed condition featuring an accordion-like member biasing the sliding sleeve; 
     FIG. 12 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention in a partially closed condition featuring a spring biasing the sliding sleeve; 
     FIG. 13 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention featuring a non-rotating flexible member; 
     FIG. 14 is an enlarged, cross-sectional view, of an embodiment of the pen according to this invention in a closed condition featuring a spring to mechanically assist deployment or retraction of the pen nib; and 
     FIG. 15 is an enlarged, cross-sectional view, of the pen of FIG. 14 in a closed condition. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     As shown in FIG. 1, a pen  10  has an outer tubular barrel  12  and an inner tubular barrel  14  which are disposed to be slidable relative to each other. These barrels may be formed of a moldable material such as plastic or other material commonly employed in pens, such as wood or metal or combinations of these materials. 
     Inner barrel  14  forms an ink reservoir  16  which contains ink to be supplied to a pen nib  18 . A pen nib barrel  20  is connected at one end to the inner barrel  14  and supports pen nib  18 . Pen nib  18  is exposed at one end of pen nib barrel  20  to form a writing surface and extends through the pen nib barrel  20  into the ink reservoir  16 . Ink flows through pen nib  18  and through pen nib barrel  20  to reach the writing surface by gravity and capillary action to maintain the pen nib  18  in a wet condition for application of ink to a writing surface. Optionally, pen nib  18  may be continued wholly within pen nib barrel  20  as long as an internal end of pen nib  18  is in hydrodynamic communication with ink reservoir  16  so that ink may be applied to pin nib  18 . 
     Forward interlocking protuberance  22  and end interlocking protuberance  24  on the outer barrel  12  cooperate with an interlocking protuberance  26  and end plate  28  on the inner barrel  14  to prevent the inner and outer barrels  14 ,  12  from separating. An additional locking protuberance  30  is provided on the inner barrel to cooperate with protuberances  22 ,  24  to maintain the pen in either a locked open position, for writing (FIG.  2 ), or a locked sealed condition, for storage (FIG.  1 ). Other known mechanisms for preventing the inner and outer barrels from separating may be used in addition to or as a replacement for these protuberances. The protuberances may be placed along the barrels of the pen to provide structural support in either the open or sealed condition. Additionally, the protuberances may be sized so that it is possible to operate the opening or sealing action of the pen with a single hand. 
     As shown in FIGS. 14 &amp; 15 a, spring may be provided between the outer barrel  12  and the inner barrel  14  to bias the outer barrel  12  and inner barrel  14  relative to each other to mechanically assist retraction or deployment of the pen nib  18 . If the spring is used to mechanically assist retraction of the pen nib  18 , upon sliding the barrels apart to the writing position, the pen nib  18  is maintained in a writing position by the protuberances, as discussed above. However, a slight displacement of the barrels relative to each other enables the spring to overcome the cooperative restraintive force from the protuberances  22 ,  30  so that the pen nib will be pulled into pen  10 . A similar but reversed scenario applies where the spring is used to bias the pen into a writing position. 
     The pen  10  may be provided with a retraction/deployment mechanism (not shown), such as a standard spring and ratchet retraction mechanism, commonly used on ball point pens. Alternatively, a thumb operated sliding part, connected to or part of the inner barrel, may be located along the side of the outer barrel in a slot allowing free sliding movement. This sliding movement causes the displacement of the inner barrel  14  relative to the outer barrel  12  to activate the sealing mechanism and deploy or retract the pen nib  18 . The thumb also slides the pen nib and inner barrel into the locked writing position. One benefit of this type of movement is that the pen remains a constant length. 
     A twisting screw action retraction mechanism, such as employed by pens manufactured by the Cross Pen Co., may also be adapted to work with this sealing device, since the underlying principle of operation remains the same—that is, two barrels slide relative to each other. The barrels can be of similar or dis-similar length. 
     In a yet further alternative, a time-release mechanism, either mechanical or otherwise designed, may be used to automatically close the pen when not in use for a given period of time. One such time-release mechanism involves a spring and a resistive element, such as friction, to gradually retract the pen nib. 
     The sealing mechanism of the retractable felt-tipped pen will now be described more particularly with reference to FIGS. 3 and 4. As shown in FIG. 4, a flexible tubular membrane  32  is provided between the outer barrel  12  and the pen nib barrel  20 . The flexible membrane  32  is attached at a first location  34  to the outer barrel  12  and at a second location  36  to the felt nib barrel  20 . The flexible membrane  32  may be attached at these locations by suitable adhesive, mechanical attachment or other bonding method such as ultrasonic bonding. It may be possible for friction alone to hold the seal in a static location. Indeed, this may be preferable in certain applications, such as where the pen is designed to use disposable cartridges (which must be replaced from time to time). 
     FIG. 4 shows the pen  10  in an open condition and FIG. 3 shows the pen  10  in a closed condition. As shown in FIG. 3, when the felt nib  18  is displaced from a writing position, as shown in FIG. 4, to a sealed position, as shown in FIG. 3, (retracted), the second location of attachment to the pen nib barrel  36  moves together with the inner surface of the flexible membrane  32  so that the flexible membrane  32  undergoes a rolling motion without undergoing substantial displacement. Stating that the flexible membrane “does not undergo substantial displacement”, as used herein, means that at least one point on the membrane remains substantially constant with respect to the outer barrel, and that at least one point on the membrane remains substantially constant with respect to the pen nib barrel. These two points may move relative to each other. 
     In operation, while retracting the pen nib  18 , point B moves to the right in FIG. 4, causing the surface at point A to move up toward the outer barrel  12  and causing point C to move down to engage the surface of the pen nib barrel  20 . This rolling action will continue until the pen nib  18  is completely sealed by the flexible membrane  32  as shown in FIG.  3 . In this manner, flexible membrane  32  completely surrounds the fibers of the felt tip, preventing the drying of these fibers. Since the flexible sealing membrane completely surrounds the pen nib  18  in a closed condition, it prevents the infiltration of air to the felt tip both from the end closest to the writing opening and from within the pen body from between the inner barrel  12  and outer barrel  14 . An opposite process occurs during the deployment operation of pen nib  18 . 
     The flexible sealing membrane  32  is formed as a donut shaped membrane and may contain a fluid or gas having a positive internal pressure, reducing the effective inner diameter of the donut shape to nothing. The flexible sealing membrane  32  may have several desirable features. First, the membrane  32  may be flexible so that it freely revolves as the outer surface replaces the inner surface, and the inner surface replaces the outer surface. Second, the membrane  32  should be able to engulf the nib so that it will form a seal when the nib is enclosed by the flexible membrane  32 . 
     Several alternative designs for the flexible membrane  32  are contemplated. One possibility uses a suitable plastic or elastomeric material to form a flexible outer membrane, like a latex balloon, in the shape of a donut filled with a liquid or gas under pressure. The “balloon” may be made of rubber, latex, neoprene, plastic, or any material which is expandible, flexible and can hold its original shape. The balloon may be unfilled, or may be filled with air or a fluid such as water, silicone jel, or any appropriate fluid which enables the flexible membrane to retain an appropriate shape. 
     Another possibility for the seal would be a tube having a zero inch interior diameter made out of neoprene or similar material. The two ends of this tube turn inside-out and adhere to each other forming an elongated donut shape. Several advantages are apparent with this neoprene solution. First, there would be no possibility of liquid leaking from the sealing membrane, as the membrane and the pressurizing medium are one and the same. Neoprene is highly resistant to chemical failure from a wide range of inks, thus damage to the seal by chemically aggressive inks is not likely. Further, the manufacturing process for reversing a neoprene tube would be simple and inexpensive. The neoprene tube solution would also be effective if the tube was inside-out, as in the previous example, but not necessarily adhered to itself. In this case, as shown in FIG. 5, the tube would resemble a rolled up shirt sleeve. The large free end of the reversed tube adheres directly to the inner surface of the outer pen barrel at  34 . The small free end of the tube adheres to the outer surface of the inner pen barrel at  36 . In this configuration, it would not be necessary to have the tube adhered to itself to make a continuous loop or donut shape. A minute quantity of lubricant may be provided on surfaces of the flexible sealing membrane  32  away from the pen nib  18  to minimize friction associated with opening and closing the pen. 
     Referring to FIGS. 3 &amp; 4, the flexible sealing membrane  32  preferably adheres to the outer surface of the felt tip barrel  20  just behind the base of the fibrous portion of the nib  18 , at position  36 . 
     The angled walls  40  of the outer barrel  12  guide the nib  18  and the nib barrel  20  to an opening  42  at the tip of the outer barrel  12 . This funneling action accurately guides the nib  18  to an appropriate writing position. Further, when the nib  18  is fully extended, the outer surface of the pen nib barrel  20  and the inner surface of the opening  42  cooperate to support the pen nib  18  to enable pressures applied to pen nib  18  during writing to be directly absorbed by the pen body, as shown in FIGS. 14 &amp; 15. 
     A shirt pocket clip  44  (FIGS. 1 &amp; 2) may be provided so that the pen may be easily carried by the user. Providing the shirt pocket clip at the opening end of the pen  10  is further advantageous in that it helps to protect this side of the pen, while using gravity to help ensure that ink flows away from the tip when in storage in a pocket. 
     A sleeve  51  (illustrated in FIGS. 5,  6 ,  7  &amp;  8 ) may be provided to cover the felt tip when in a closed position to prevent ink from leaching onto the flexible membrane  32  or from contaminating the surface of the flexible membrane  32  with ink. As shown in FIGS. 6,  7  &amp;  8 , the sleeve slides back when in a writing mode to expose pen nib  18 . Sleeve  51  surrounds and is free to move with pen nib barrel  20 . By a series of precise crimping and molded protuberances  52 ,  53 ,  54  &amp;  55  (FIGS.  7  &amp;  8 ), sleeve  51  engages the pen nib barrel  20  during retraction to cover pen nib  18 . The sleeve  51  then reveals the pen nib when the pen is deployed to a writing position. The sliding sleeve may be formed of plastic, metal, wood or any material which is rigid and can be shaped through molding, turning, casting, or any other method. 
     The sleeve may be provided with protuberances  52  which engage the inner walls of the outer barrel  12  to lock the sleeve when open. This allows the inner barrel to slide relative to the sleeve until the felt tip is covered. At that point, the sleeve crimp  54  engages a protuberance  55  on the inner barrel  20  as it is moving (FIGS.  6  &amp;  7 ). The sleeve is pulled away from its locked position on the outer barrel and moves with the inner barrel as it becomes covered by the flexible sealing membrane (FIGS. 8,  7  &amp;  6  in sequence). 
     In achieving an opened position, FIG. 8, from FIG.  6  and FIG. 7, the sleeve  51  remains stationary, relative to the felt tip nib  18  as the flexible membrane  32  is being peeled away (FIG.  7 ). When the sleeve angle  56  comes in contact with the angled opening of the inner wall of the outer barrel  40 , it stops moving relative to the inner barrel. The felt tip nib  18  is guided with the sleeve  51  through the opening until a protuberance on the sleeve  52  contacts an indentation  53  on the tip of the outer barrel  12 . The sleeve is then forced to a locking position when the pen is fully opened, FIG.  8 . 
     Although a sleeve of this nature may be provided, it may not be necessary to provide a sleeve of this nature—since the user is never in contact with any portion of the sealing member, contamination of the sealing member should not affect the performance of the pen negatively. The sleeve is precautionary only. 
     Alternatively, as shown in FIGS. 9 &amp; 10, the surface of the flexible membrane  32  may be indented at a location corresponding to the exact position of the felt tip when the pen is in a sealed condition FIG. 9 to form an air space  60  surrounding the pen nib. By forming an air space  60  of this nature, ink from the pen nib can be prevented from contaminating the surface of the flexible membrane. The indentation rolls with the flexible membrane  32 . 
     A yet further alternative to using a sliding sleeve is to use a segmented rigid cylinder, attached to the sealing membrane, to surround the felt tip fibers when in the sealed condition. To facilitate turning back of this cylinder, the cylinder is divided and separated into multiple tessellated tiles or scales. These individual pieces move with the flexible membrane as it is turned back. Each tile or scale is attached separately, but cooperate when sealed to form gap  60 . The closest example is the skin of a snake where each scale is individually attached to the skin, separated by flexible connections, which allows the snake to expand when necessary. The effect of this mechanism is similar to the indentation illustrated in FIGS. 9 &amp; 10. 
     Another alternative to providing a sliding sleeve is to fit the pen nib with an accordion-like spring  61  (FIG. 11) which expands to force the sliding sleeve  51  to cover the felt tip fibers when the pen is in a sealed condition. When the pen is opened to expose the pen nib  18 , the accordion-like spring forces sleeve  51  up to and against the inner wall of the outer barrel at the pen tip hole. The accordion-like spring is resisted by the contact of the sleeve at point  56  with the outer barrel angle  40  while the inner barrel continues to slide, exposing the pen nib. A reverse process takes place during the sealing process when the pen nib is retracted. The sliding sleeve  51  may be separate from or connected to the accordian-like expanding member  61 . 
     This accordion-like member  61  may be formed from a variety of materials, such as plastics, rubbers or other synthetic and/or naturally occurring materials. The accordion-like member  61  expands by a bellows action to force the sliding sleeve  51  to cover the felt nib  18 , and is retracted by bellows action resisting the sliding sleeve thereby revealing the nib  18 . This action could also be by simple contraction and/or simple deflection of the material of the accordion-like member  61 . In either case, the mechanism involved relies on the property of shape memory inherent in the accordian-like member and its action relative to the covering sleeve. The sleeve may be fixed to or independent of the inner barrel. 
     Alternatively to the bellows action of member  61  is a spring  62  shown in FIG.  12 . Like the action of the bellows, the spring  62  forces the sliding sleeve  51  against the walls of the outer barrel  40 . Upon retraction, the sliding sleeve is eventually pulled back with the inner barrel  20  to cover the felt nib  18 . 
     FIG. 13 illustrates a sealing member  32  which expands to seal nib  18  without any rotating action. This mechanism may or may not be used in conjunction with separate sliding sleeves as previously described. In this instance, a quantity of pen ink will bleed onto the surface of the sealing member  32  to enable the pen nib  18  and pen nib barrel  20  to easily slide within sealing memebr  32 . 
     It is understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the scope and spirit of this invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description as set forth herein, but rather that the claims be construed as encompassing all the features of patentable novelty that reside in the present invention, including all features that would be treated as equivalents thereof by those skilled in the art to which this invention pertains.