Abstract:
A capless retractable sealed marking instrument has a sealed chamber incorporated in a marker casing. The sealed chamber includes a chamber, a wiper ring, and an annular rim and a seal portion with a cross-slit aperture defining surfaces or flaps which are moved out of contact by a linearly-advanced marker nib to open the seal for extension of the marker nib. The configuration of the disk provides positive sealing force between the lateral sealing surfaces of the seal flaps. Retraction of the marker nib draws the flaps back into the sealed chamber configuration to protect the marker nib and cartridge from atmospheric degradation.

Description:
RELATED APPLICATIONS 
   This application is a continuation of International Application No. PCT/US03/04394, filed Feb. 13, 2003, entitled “Capless Retractable Sealed Marking Instrument with Forward Chamber.” That application claimed the benefit of U.S. Provisional Patent Application No. 60/356,314, filed Feb. 13, 2002, under the same title. 

   FIELD OF THE INVENTION 
   The present invention pertains generally to marking and writing instruments and, more particularly, to marking and writing instruments having ink-impregnated applicators or cartridges with means to maintain a sealed, airtight chamber in which to house the tip. 
   BACKGROUND OF THE INVENTION 
   Capless markers are known in the prior art. Commonly-owned U.S. Pat. No. 6,033,141 is hereby incorporated by reference in its entirety. Generally, these markers provide a retraction and extension carriage to permit the tip of the marker to be concealed within a housing when not in use so as to avoid accidentally contacting clothing or papers when not in use. 
   Some capless markers include a seal to prevent the drying of the tip due to evaporation of ink into the atmosphere. One such marker is disclosed in the above-referenced patent, U.S. Pat. No. 6,033,141, issued to Blaustein, et al. The marker discloses a single-piece seal mounted adjacent a front cowling. The single-piece seal includes a concave membrane with a slit to permit the extension of the ink cartridge tip for writing and closes upon retraction of the ink cartridge. 
   A variety of carriage mechanisms may be employed for linear movement of the cartridge within a marker housing. Because the carriage, by necessity, involves moving parts, there is a likelihood that the carriage mechanisms do not provide an airtight closure at the end opposite the writing tip of the marker. Therefore, infiltration of air from the carriage end of the marker can occur despite the placement of a seal adjacent the tip. 
   There is thus absent from the prior art a retractable capless marker which provides a securely-maintained, airtight chamber of a relatively simple design, which eliminates the need for a separate cap, and which prevents drying of the nib due to air infiltration from either the front or rear end of the marking instrument. 
   SUMMARY OF THE INVENTION 
   The capless marker is a highlighter-type of marker that incorporates seal technology to allow the marker to be used without a cap. Preferably, the marking instrument uses a fluorescent-highlighter ink which may be produced in multiple colors, such as yellow and pink, although virtually any type of ink or shape of nib may be used with this device. 
   What is disclosed is a capless retractable sealed writing instrument including an elongated marker housing with an axial opening. A marker reservoir having a marker nib is disposed within a marker carrier mechanism in the marker housing. The marker carrier mechanism moves the marker reservoir and marker nib linearly within the marker housing to extend and retract the marker nib through the axial opening in the marker housing. 
   A sealing means includes a sealing chamber, a first seal piece, and a second seal piece. The chamber has a peripheral wall defining a hollow bore. The chamber is disposed coaxially within said reservoir. The reservoir extends at least partially into the hollow bore of the chamber when it is in the retracted position. 
   The sealing chamber comprises a generally circular peripheral wall defining a hollow bore suitable for passage of a cylindrical reservoir portion. An annular forward terminus at one end of the peripheral wall is adapted to compress an annular rim of the first seal portion. An annular rearward terminus at an opposite end of said peripheral wall has a flat edge adapted for compressing an elastomeric wiper seal encircling the reservoir portion. 
   The seal portion comprises an annular flange portion in contact with the forward terminus, a circular head portion; and a hollow cylindrical sidewall connecting said forward terminus and said head portion. The head portion includes a flexibly-resilient, re-closable aperture adapted to permit extension and retraction of the marker nib through the head. 
   One advantage of such a marker is that a detachable cap is not required in order to prevent the marker from drying out. Frequently, detachable caps are set aside and lost or forgotten by the user, and much of the ink remaining in the marker is wasted when the nib dries out and becomes hard. 
   It is therefore an object of the present invention to provide an airtight seal in which to maintain the marker nib when in the retracted position. 
   It is a further object of the present invention to eliminate the need for a removable cap to prevent evaporation of the ink and drying of the nib. 
   It is yet another object of the present invention to maintain, in a fixed position, a sealed chamber for storing the marker nib and to ensure a positive engagement of a secondary seal with the chamber. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevational view of a sealed capless marking instrument; 
       FIG. 2  is a sectional view taken along lines  3 - 3  of  FIG. 1 ; 
       FIG. 3  is an exploded isometric view illustrating the arrangement of internal parts; 
       FIG. 4  is an enlarged sectional view of the tip assembly portion; 
       FIG. 5  is a cross-sectional view of the tip portion when the nib is in the extended position; 
       FIG. 6  is an isometric view of the sealed chamber; 
       FIG. 7  is an elevational sectional view of the sealed chamber; 
       FIG. 8  is a plan view of the seal piece; 
       FIG. 9  is a cross-sectional view of the seal taken along the lines  9 - 9  in  FIG. 8 ; 
       FIG. 10  is an isometric view of the seal piece; 
       FIG. 11  is a plan view of an alternate concave seal piece; 
       FIG. 12  is a cross-sectional view of the alternate concave seal taken along the lines  12 - 12  in  FIG. 11 ; 
       FIG. 13  is an isometric view of the seal piece; 
       FIG. 14  is a sectional schematic view of an alternate chamber configuration; 
       FIG. 15  is a sectional schematic view of an alternate chamber configuration; 
       FIG. 16  is sectional schematic view of an alternate chamber configuration; 
       FIG. 17  is an isometric view of an alternate sealed chamber with internal ribs; and 
       FIG. 18  is a cross-sectional view of an alternate sealed chamber with internal ribs. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Using the above-identified Figures, the invention will now be described with respect to various preferred embodiments. 
   The present invention discloses a means for sealing the nib portion of a marking instrument by trapping the nib within a small, airtight chamber at the forward or writing end of the instrument. A reclosable seal is compressed against the chamber, with a resilient slit or slits that separate when the marker nib is extended through the seal for writing, and reclose to maintain an airtight barrier when the nib is again retracted. An O-ring maintained in compression against the housing forms the nib seal by friction fit against the wall of the ink reservoir. A secondary seal at the rear of the ink reservoir is maintained, so as to prevent exposure of the ink to air that can cause premature drying, from the end opposite the nib. 
   By this means, a small, airtight pocket is formed around the marker nib when in the retracted position, thereby substantially eliminating evaporation of the ink through the nib. Secondarily, the rear portion of the reservoir is also sealed from the atmosphere to prevent evaporation of ink from the internal fibers in the reservoir. These two sealing means allow the marker to move longitudinally along the axis of the marker by conventional retracting means, and to maintain a seal when retracted, thus only exposing the nib of the marker to air when in use. 
   The Marking Instrument Housing 
   Referring first to  FIG. 1 , the sealed capless marking instrument is generally designated as  10 . A tip portion  12  is attached at the forward end of instrument  10  to a housing portion  14 . Housing portion  14  is comprised of a first housing portion  16  and a second housing portion  18 . A reservoir plunger  20  protrudes from second housing portion  18  from within housing  14 . 
   Referring next to  FIGS. 2 and 3 , release button  22  is provided for retracting a reservoir assembly  54  to conceal nib portion  48 . Reservoir assembly  54  is contained within housing portions  16 ,  18 , which join to form the single housing portion  14 . At the forward end of the marking instrument used for writing, the tip portion is attached via a solvent bond or a snap connection  36  to first housing portion  16 . A snap connection  56 ,  36  is comprised of a plurality of complementary ridges that interlock when forced together. Other connection means, such as threads and bayonet-type fittings, are also effective. Tip portion  12  engages first housing portion  16  via snap connector  36  and maintains the position of chamber portion  30  against a wiper seal  34  made of elastomeric material, such as silicon rubber, at one end and seal portion  32  at the forward end. Wiper seal  34  has a generally L-shaped, cross-sectional configuration conformable to the outer diameter of chamber portion  30 . Alternately, the wiper seal  34  may be replaced by an O-ring or a gasket. Chamber portion  30  maintains an airtight cavity in which nib portion  48  is encased when marker  10  is in the retracted position. The limited space contained within chamber portion  30  prevents nib portion  48  from drying when in the retracted position, thereby extending the shelf life of the capless marker  10 . 
   Referring next to  FIGS. 4 and 5 , the forward portion of marker  10  is illustrated as an enlarged, cross-sectional view. The tip portion  12  attaches to the first housing portion  16  by means of snap connection  36 . The tip portion  12  protects and conceals the concave seal portion  32  which rests adjacent shoulder  72 . The chamber portion  30  is maintained within the forward end of the first housing portion  16  by the tip portion  12  when the tip portion  12  is engaged with first housing portion  16 . Chamber portion  30  abuts wiper seal  34 . Wiper seal  34  rests against an annular rim portion  58  projecting radially-inward from a housing lining wall  42 . Rim portion  58  provides a stop limit to prevent axial displacement of the chamber portion  30 . Compression spring  26  rests against annular rim portion  58  on the opposite side of wiper seal  34  within the hollow interior of the marker housing portion  14 . Compression spring  26  is compressed when the marker  10  is in the extended position and stores energy that is released when release button  22  is depressed, forcing the reservoir assembly  54  to return to the retracted position. 
   As illustrated in  FIGS. 2 and 4 , when in the retracted position, the nib portion  48  is situated within the hollow interior of the chamber portion  30 , so as to trap the nib portion  48  in an airtight, sealed chamber. The seal is achieved by the closure of slits  28  in seal portion  32 . Slits  28  permit the penetration of nib portion  48  when the reservoir assembly  54  is extended to expose the marker for writing. When the seal portion  32  is closed in the retracted position, the forward end of the chamber portion  30  is sealed by way of the rim portion of seal  32 . The seal portion  32  is further described in detail below. The opposite end of the chamber portion  30  is sealed by way of a wiper  34  which is compressed against the annular rim portion  58  and which also snugly fits about the external diameter of capillary reservoir housing  50 , so as to prevent any air infiltration from the end of the marking instrument opposite the tip portion  12 . 
   A contoured shape is preferred in the marker housing, with an indentation  17  formed in the first housing portion  16  located proximate to the tip portion  12 . This assists the user in gripping the instrument for ease of writing. Housing portion  14  has a generally oblong, cross-section in second housing portion  18 , transitioning into a circular cross-section in bottom portion  16 . The non-circular geometry helps prevent the marking instrument from rolling on a flat surface, such as a desk, when it is laid down. The circular terminus of housing portion  14  facilitates the connection of a substantially conical tip portion  12  to the housing portion  14 . 
   The Seal Chamber 
   Referring next to  FIGS. 6 and 7 , the chamber portion is generally designated as  30 . An aperture  100  extends through a top rim portion  108  through which the reservoir assembly  54  extends. Exterior walls  102 ,  104  are stepped at such a way as to form a tandem pair of cylindrical walls, first wall  102  being the wall portion nearest aperture  100 . First wall  102  is of a smaller diameter than second wall  104 . While the walls  102 ,  104  are generally cylindrical, as it is desirable to include a slight taper from the one end to the opposite end in order to facilitate injection molding processes, which are more easily accomplished when the workpiece includes a slightly tapered exterior wall. Second wall  104  attaches to a flange  106  at the end opposite aperture  100 . 
   The chamber portion  30  is similar in appearance to a thimble open at both ends, and includes a flat top rim portion  108  which engages wiper seal  34  and forces it against annular rim portion  58 . Rim portion  58  and wiper seal  34  form an airtight seal around reservoir assembly  54  at one end of chamber portion  30 . At the opposite end, flange  106  engages the seal portion  32  and provides an airtight fit. 
     FIGS. 4 and 7  illustrate a dovetail recess  72  formed at the intersection of flange  106  and tip portion  12 , that captures flange portion  104  of seal  32  to prevent the seal from becoming dislocated. An angled surface  110  on the bottom side of flange  104  depresses the pliable material of the annular flange portion  104 . 
     FIGS. 17 and 18  illustrate an alternate configuration of a chamber portion  130 , having a plurality of interior vertical ribs spaced generally symmetrically about the internal circumference of the chamber walls. 
   The Seal 
   Referring next to  FIGS. 8-10 , seal portion  32  is shown in a preferred arrangement. Various configurations may be employed in constructing seal portion  32 . One such device is shown and described in U.S. Pat. No. 5,439,143, which is expressly herein incorporated by reference in its entirety. This device, entitled “Dispensing Valve For Packaging,” is manufactured by Liquid Molding Systems, Inc., of Midland, Mich. While not used as a valve in the present invention, the present invention employs the resealable properties of such a valve to seal the marker nib  48  within the forward chamber  30 . For clarity, the device is referred to as a seal for purposes of this invention. Without setting forth the entire details of the seal construction, the relevant portions will be discussed. The seal  30  contains aperture  116  with a cross-slit construction that includes two intersecting linear slits  118  and  120  that extend through the center portion  106 . Slits  118 ,  120  are formed preferably by slicing through the center portion  106  of seal portion  32 . 
   The illustrated seal portion  100  comprises an integral, single-piece construction, preferably made of a resiliently flexible and pliable material, such as silicon rubber. A thin barrier of propylene glycol or other non-toxic gel may be applied to enhance the sealing properties and to lubricate the aperture  116  and the marker nib  48  to reduce wear on the seal  100  due to repeated operation of the retracting mechanism. 
   Flange portion  104  is compressed between forward chamber  30  and shoulder  72  of tip portion  12 . Flange portion  104  is connected to longitudinal sidewalls  102  via flexible trough  110 . Longitudinal sidewalls  102  of seal portion  100  extend outwardly forming a hollow cylindrical guide path for marker nib  48 . Sidewalls  102  terminate into head  108 . Head  108  has an arcuately-shaped marginal portion tapering from sidewalls  102  to a generally flat center portion  106 . An aperture  116  has a pair of perpendicularly-intersecting linear slits  118 ,  120  that extend completely through center portion  106 , and their distal ends are tapered slightly inwardly from the radial edge of center portion  106 . Slits  118 ,  120  define four flaps  122 , which flex outwardly and back corresponding to the direction of travel of the nib  48 . 
   Flaps roll outwardly when nib  48  is in the extended position, maintaining a slight pressure around the shaft of the nib  48 . When the nib  48  is retracted, flaps  122  gently wipe any excess ink and return to a closed, sealed position. 
   It is to be understood that aperture  116  may assume many different shapes, sizes and/or configurations in accordance with the marker characteristics desired. For example, aperture  116  may comprise a single slit, particularly when smaller or narrower streams are desired. Aperture  116  may also include three or more slits, for example, as when a geometric cross-sectional reservoir, such as a hexagonal tube, is desired. Other forms of apertures  116 , such as holes, duck bills, etc., may be incorporated into seal  32  in lieu of the cross-slits to enhance the sealing properties. 
   Carriage Mechanism 
   Reservoir plunger  20  is attached by way of a multi-ringed snap connection and complementary ridges on a reservoir connection  40 , which interlock with each other when pressed together. In the disclosed embodiment, reservoir plunger  20  is elliptical in cross-section, and the reservoir connection  40  has a corresponding elliptical cross-section on the side that couples with the reservoir plunger  20 . 
   As shown in  FIG. 2 , a recoil spring  80  may be optionally deployed within the reservoir plunger  20 . The purpose of recoil spring  80  is to cushion the reservoir from the recoil impact when release button  22  is depressed and spring  26  retracts nib  48 . Cushioning is desirable in order to prevent or limit deformation of ink fibers (not shown) from occurring within reservoir  50 . 
   A plug  82  fits snugly into the end of capillary reservoir  50  to seal the internal fibers  54  from atmosphere. Shelf  84  on plug  82  provides a circular base for securing one end of recoil spring  80  within reservoir plunger  20 . Hub  86  extends from plug  82  to position recoil spring  80 . 
   Referring next to  FIGS. 2 and 3 , the capillary reservoir housing  50  is slidable along a longitudinal axis to permit the nib portion  48  to extend through concave seal portion  32  and beyond housing portion  14  through an opening  15 . The release spring  38  is attached to the capillary reservoir housing  50  via a pair of protrusions  64  on reservoir connection  40 . Protrusions  64  engage release spring  38  in a fixed position relative to the release button  22  and a slot  62  when in the retracted position. By pressing the reservoir plunger  20 , the capillary reservoir housing  50  advances along the longitudinal axis until the release spring  38  engages the release button  22 . When external pressure is applied to the release button  22 , for example, by a person&#39;s thumb, reservoir assembly  54  returns to the retracted position by releasing the energy stored in compression spring  26 . Release spring  38  is forced back until it engages the first slot  62 . 
   It is to be understood that the disclosed carriage mechanism employed in the present invention represents but one of many such mechanisms known in the art. For example, a rotary cam-follower or a ratchet mechanism may be substituted for the release spring/pushbutton arrangement disclosed herein. 
   Reservoir Assembly 
   Referring next to  FIGS. 2 and 3 , the reservoir assembly is illustrated.  FIG. 2  shows the nib portion  48  which is adjacent one end of capillary reservoir assembly  54 . Nib portion  48  is maintained adjacent capillary reservoir assembly  54  partially by a friction fit between the inner walls of capillary reservoir assembly  54  and a cylindrical shaft  47  of nib portion  48 . Nib portion  48  extends backward into capillary reservoir assembly  54  in which the ink is impregnated. Capillary reservoir assembly  54  is contained within capillary reservoir housing  50 . Capillary reservoir housing  50  is comprised of a pair of tubular sections  74 ,  76 . First tubular portion  74  is of a smaller diameter which contains the forward nib portion  48  extending out of the end of the first tubular portion. The first tubular portion  74  is joined with the second tubular portion  76  of a larger diameter, which extends rearward into the hollow interior cavity of reservoir plunger  20 . A shelf  75  is defined at the connection between tubular sections  74 ,  76 . Shelf  75  provides a circular base for securing one end of compression spring  26 . The second tubular portion  76  may contain a larger diameter filament or capillary reservoir assembly  54 . The nib portion  48  and capillary reservoir assembly  54  are constructed of a polyester fiber in the disclosed embodiment and impregnated with a writing fluid, such as fluorescent ink or the like. 
   A wide variety of inks may be employed in the reservoir assembly  54 ; however, the characteristics of the ink used in the disclosed embodiment include odorless, quick-drying, water-resistant, fade-resistant, and non-toxic fluid consistent with ASTM 4236 Standard. The nib portion  48  may be chisel-shaped for highlighting purposes or more pointed for writing purposes. 
   The seal  32  may incorporate a thin plastic membrane covering the seal portion  32 , which is punctured at the first use so as to provide additional protection and preserve the ink stored therein during the shelf life period prior to the first use. 
   Alternate Seal Configurations 
   Concave seal  232 , shown in  FIGS. 12-14 , is held within the marker tip portion  12 . The seal  232  includes a generally annular rim  201  with an internal diameter (ID) at least equal to or greater than a diameter of an opening  15 . 
   Annular rim  201  includes a flat edge  210 . Flat edge  210  provides alignment means to orient the direction of the slit  28  to coincide with the edge of a nib chisel point  49 . Flat edge  210  prevents the rotational movement of the seal  232 , relative to chamber portion  30  and tip portion  12 , after the tip portion  12  is snapped together with the housing  14 . When using a flat edge  210  type rim  201 , the chamber portion  30  may have a flat, rather than tapered, flange bottom  110 . A semi-circular or pointed bead (not shown) optionally depends from the flange bottom  110  that will impinge upon the rim  201  for better engagement with the chamber portion  30 . 
   The seal  232  further includes a flexible concave disk  202  attached to and within the circular interior area defined by the annular rim  201 . As best shown in  FIG. 13 , the concave disk  202  has a cross-section in the form of an arc A, with an apex  203  of arc A oriented to face the marker nib  48  when the marker nib  48  is in a fully-retracted position within the marker housing  14 . The concave disk  202  further has a full-diameter, full-width slit  204  through the radial center of the disk, which forms two cooperative sealing disk halves  205 ,  206  which are deformable to allow passage of the marker nib through the slit upon linear advancement of the marker cartridge and marker nib by the marker carrier mechanism to an extended position. 
   The concavity of the disk halves  205 ,  206  biases mating edges  207 ,  208  tightly together to form a highly-effective atmospheric seal to the interior of the marker housing, thereby retaining the ink moisture in the marker nib and the marker cartridge. The concavity of the disk halves with an apex  203  oriented into the interior of the marker casing and toward the marker tip is especially effective in forming a seal sufficient to retain moisture within the marker cartridge and nib. As shown in  FIG. 5 , the marker nib is linearly projected through the seal  232  and opening  15 , thereby deflecting the disk halves  205 ,  206  to spread about the slit. In this position, the disk halves are tightly wrapped about the circumference of the marker cartridge, thereby effectively sealing the section of the marker reservoir, which remains in the housing  14  from the atmosphere, while the marker nib is exposed. Upon retraction, the disk halves  205 ,  206  effectively wipe the marker nib clean as they are brought back to the sealed concave position by the linear motion of the cartridge. The concave configuration of the disk halves  205 ,  206  is especially effective in establishing a tight seal since the amount of force required of the tip to urge the halves apart is greater than required for a convex, outwardly-oriented seal. Also, upon retraction, the marker nib mechanically drags the disk halves back to the concave position, forcing the mating surfaces together to reestablish the seal  32 . 
   The seal  32  is preferably formed or molded in the described configuration from a suitable silicon material such as GE.RTM. Silicon SE 6260, a high-performance, moldable, and pigmentable silicon compound. 
   Referring to  FIGS. 14-16 , it is also within the scope of the present invention and the appended claims to include the flexible seal portion attached to the forward chamber, either by adhesively affixing the seal portion on the rim or by integrally molding the seal onto the forward chamber ( FIG. 14 ). Additional configurations are shown on  FIGS. 14-16  and include a traveling sealed chamber ( FIG. 15 ) and a bellows-type extendable seal ( FIG. 16 ) attached at one end to the reservoir cartridge. 
   A vent tube (not shown) may be placed longitudinally within capillary reservoir assembly  54  to equalize pressure within the reservoir to prevent vapor-lock and facilitate the flow of ink to the nib  48 . 
   Although the present invention has been described above by reference to an embodiment of the invention, the present invention is not limited to the embodiment described above. Modifications and variations of the embodiment described above will occur to those skilled in the art, in light of the above teachings without departing from the spirit of the present invention. It is the present invention, therefore, to be limited only as indicated by the scope of the claims appended hereto.