Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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COMBINATION WRITING INSTRUMENT
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation-in-part of United States
patent
application No. 10/706,315 filed November 11, 2003, which application is
hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a writing instrument and, in
particular, a
writing instrument having at least two writing elements that are axially
moveable with
respect to one another, and more particularly, with one writing element being
disposed
within the other writing element. The present invention also relates to
improvements to
filler-type writing instruments.
BACKGROUND OF THE INVENTION
[0003] Writing instruments having multiple writing elements are well known in
the
art. For the most part, these writing instruments have a plurality of writing
elements
disposed adjacent (side-by-side) to one another within a pen barrel. Prior art
writing
instruments have combined a variety of types of writing elements, including
ball point pens,
highlighters, and markers, in various combinations (e.g., all the same type,
one of each, or
more than one of more than one type). A drive mechanism is actuated to
displace the
writing tip of one of the writing elements to a position outside the barrel.
In some eases,
one writing instrument is already in a fixed position outside the barrel and
the second
writing element is moveable.
[0004] In order for the moveable writing element to be used for writing, it
must be
projected out of the barrel past the distal-most portion of the fixed writing
element. In other
known writing instruments, the distal-most portion of the moveable writing
element - when
fully projected - is in the same plane as the distal-most portion of the fixed
writing element.
Therefore, the two writing elements can produce two lines, or a line with a
thickness greater
than either writing element individually. Also, if the writing elements are
supplied by two
different writing mediums, two different lines can be produced.
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[0005] The disadvantage of side-by-side construction is that the diameter of
the pen
barrel housing the writing elements must be greater than the diameter of a
standard pen
having only one writing element. To create a more compact writing implement,
prior art
devices have mounted the writing elements coaxially (i.e., one writing element
disposed
within another writing element), whereby the inner writing element is moveable
relative to
the outer writing element.
[0006] Various compact, multiple-writing-element writing instruments currently
exist. These instruments have several distinguishing features. For example,
U.S. Patent
5,026,189, filed on April 5, 1990, and issued to George Keil on June 25, 1991,
discloses a
writing instrument having a pen barrel with two writing elements coaxially
mounted therein.
The inner writing element moves axially relative to the outer writing element.
In one
embodiment, each writing element has its own ink reservoir. The driving
mechanism for
moving the inner writing element relative to the outer writing element,
however, is located
towards the center of the pen barrel. Consequently, the writing tips must be
separated from
their respective ink reservoirs. The construction of such a writing instrument
thus is
complex and difficult to assemble en mass. Other prior art devices have inner
and outer
writing elements that share a common ink reservoir, such as shown in U.S.
Patent 4,580,918
to Baker et al. Such a configuration is undesirable if an operator wants to
use different
types of writing mediums.
[0007] In addition, prior art writing instruments with multiple writing
elements have
not succeeded in providing disparate writing elements in a compact body having
an outer
diameter that is not significantly larger than the outer diameter of a
standard, single writing
element writing instrument. Thus, in order to provide a writing element such
as a pen with
a marking element such as a marker or highlighter, the writing tips have been
provided on
opposite ends of the writing instrument to maintain a streamlined appearance
and relatively
standard outer diameter for a writing instrument. Use of such writing
instruments results in
wasted motion when manipulating the orientation of the writing instrument to
switch
between writing ends to achieve different writing or marking modalities. Also,
each writing
element typically is covered by a separate cap. Thus, the use of both.writing
elements
during a single writing / marking task requires the further wasted motions of
removing and
replacing two caps, instead of a single or no cap. Moreover, the user has to
keep track of
two caps, instead of a single or no cap.
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SUNINIARY OF THE INVENTION
[0008] A writing instrument in accordance with one aspect of the present
invention
has an outer barrel housing an inner writing element coaxially mounted within
an outer
writing element. The writing elements are axially moveable with respect to
each other.
Preferably, the inner writing element is made of a material chosen for its
rigidity and
resistance to corrosion.
[0009] In order to operate the writing instrument of the present invention, at
least
one writing element is connected to a driving mechanism. The driving mechanism
causes
axial movement of one writing element with respect to the other writing
element. In
operation, one writing element may be fixed so that at least a portion of its
writing tip
remains outside the barrel, allowing the writing instrument to be used to mark
a writing
surface. The other writing element is axially moveable. Upon actuation of the
driving
mechanism, the moveable writing element is extended from the barrel so that
its distal-most
portion extends beyond the distal-most portion of the fixed writing element.
Now, the
moveable writing element can be used to mark a writing surface.
[0010] In accordance with another aspect of the present invention, a writing
instrument is provided with a replaceable filler-type writing element having a
filler-type
writing medium reservoir and a porous nib. A fluid-impervious sleeve
preferably covers at
least a portion of the porous nib and/or the filler-type writing medium
reservoir of the
writing element. The sleeve enables the user to handle the filler-type writing
medium
reservoir and the porous nib without getting writing medium on his/her hands
and/or
fingers. To enable refill of the writing element, the outer barrel of the
writing instrument is
designed to permit access to the writing element.
[0011] The construction of a writing instrument as described herein meets the
needs
of modern day users of writing instruments. Such a construction allows two
different
writing elements (e.g., pen and highlighter/marker) to be used. For example,
those who edit
written works can perform two independent functions - annotating and
highlighting - with
the same writing instrument.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention can be better understood by reference to the
following
drawings, wherein like references numerals represent like elements. The
drawings are
merely exemplary and the present invention is not limited to the embodiments
shown.
[0013] FIG.1 is an elevational view of an exemplary writing instrument formed
in
accordance with principles of the present invention;
[0014] FIG. 2 is a perspective view of two writing elements that may be used
in a
writing instrument formed in accordance with the principles of the present
invention, the
writing elements being shown in isolation with one writing element inserted
over the other
writing element;
[0015] FIG. 3 is an exploded view of a writing instrument as in FIG.1;
[0016] FIG. 4 is a longitudinal cross-sectional view of the back barrel of a
writing
instrument as in FIG.1;
[0017] FIG. 5 is a longitudinal cross-sectional view of an exemplary porous
nib for
an outer writing element in accordance with the principles of the present
invention;
[0018] FIG. 6 is another longitudinal cross-sectional view of an exemplary
porous
nib for an outer writing element in accordance with the principles of the
present invention;
[0019] FIG. 7 is a cross-sectional view of an exemplary outer writing element
in
accordance with the principles of the present invention;
[0020] FIG. 8 is a cross-sectional view of another exemplary outer writing
element
along line VIII-VIII of FIG. 2;
[0021] FIG. 9 is an exploded view of an embodiment of a front barrel engaging
an
exemplary driving mechanism of a writing instrument formed in accordance with
the
principles of the present invention;
[0022] FIG.10 is a perspective view of another embodiment of a front barrel
engaging a second exemplary driving mechanism of a writing instrument formed
in
accordance with the principles of the present invention;
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[0023] FIG.11 is an exploded alternative view of components making up a third
embodiment of a driving mechanism of a writing instrument;
[0024] FIG.12 is an exploded view of an exemplary drive mechanism and writing
instrument;
[0025] FIG.13 is a cross-sectional view of an exemplary writing instrument
with
another embodiment of a drive mechanism.
[0026] FIG.14 is an exploded view of an exemplary cap that may be used on a
writing instrument formed in accordance with the principles of the present
invention;
[0027] FIG.15 is an exploded view of another exemplary cap that may be used on
a
writing instrument formed in accordance with the principles of the present
invention;
[0028] FIG.16 is an exploded view of the components of an exemplary
replacement
mechanism; and
[0029] FIG.17 is a perspective view of an exemplary refill set.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Referring now to FIG.1, exemplary writing instrument 10 formed in
accordance with the principles of the present invention, has an outer barrel
12 housing inner
writing element 20 and outer writing element 22, such as illustrated in FIG.
2. It should be
noted that the term "writing element" is not limited to a writing element in
its literal sense
but, instead, covers any element having any medium that can be applied to a
substrate,
including glue or correction fluid. Likewise, reference to "writing" or
"marking," or other
such terms, is made for the sake of convenience. The terms "writing" or
"marking" are not
limited to writing and marking in their literal sense but, instead should be
understood to
include application of other mediums or substrates such as glue or correction
fluid. As
illustrated in the embodiment of FIGS.1 and 3, outer barrel 12 may comprise
front barrel
14, back barrel 16, and front nose cone 23, extending, preferably, along
longitudinal axis
11. Front and back barrels 14,16 may be moveably coupled together for purposes
as will
become apparent. Front barrel 14 is positioned over writing elements 20, 22 at
distal end
41, and back barrel 16 is positioned over writing elements 20, 22 at proximal
end 43.
Moreover, writing instrument 10 may have a grip (not shown) on front barrel
14, which may
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be made of, for example, soft rubberized paint or a separately formed
elastomeric grip
element.
[0031] Front and back barrels 14,16 can be made of the same or different
materials.
For example, front barrel 14 can be made of ABS (acrylonitrile butadiene
styrene) and back
barrel 16 can be made of polypropylene. Various factors such as strength, ease
of
manufacturing, and ability to be decorated/painted (e.g., ability to receive
rubberized paint
to form a grip) may be considered in selecting the material that may be used
for front barrel
14. Moreover, various factors such as resistance to vapor transmission or air-
tightness (i.e.,
material chosen does not allow vapor/air to flow in or out of writing
instrument 10), cost,
ease of manufacturing, and lubricity (i.e., smoothness; minimal to no friction
for ease of
moving front and back barrels 14,16 relative to each other) may be considered
when
selecting material that may be used for back barrel 16.
[0032] In one embodiment of the present invention, a portion of inner writing
element 20 is provided with first writing tip 30 positioned outside outer
barrel 12 and
available for marking operations, and outer writing element 22 is moveable
from a position
with second writing tip 32 substantially entirely within outer barrel 12 to a
position with
second writing tip 32 outside outer barrel 12. In such a configuration, inner
writing element
can be used to mark a surface. Conversely, in another embodiment, a portion of
outer
writing element 22 may be fixed and inner writing element 20 may be moveable
from a
20 position with writing tip 30 substantially entirely within outer barrel 12
to a position with
writing tip 30 outside outer barrel 12. In yet another embodiment, both
writing elements 20,
22 may be moveable from a position with a respective writing tip substantially
entirely
within outer barrel 12 to a position with a respective writing tip outside
outer barrel 12.
[0033] Exemplary relative positioning and construction of writing elements 20,
22
may be appreciated with reference to FIG. 2, in which exemplary writing
elements 20, 22
are shown co-axially mounted. This configuration, however, is not necessarily
indicative of
the position of writing elements 20, 22 within outer barrel 12. Inner writing
element 20 has
a smaller outer diameter dimension than inner axial passage 24 of outer
writing element 22
so that inner writing element 20 can fit within inner axial passage 24 of
outer writing
element 20. Thus, as shown by arrow 26, writing elements 20, 22 are capable of
axial
movement with respect to each other.
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[0034] Inner writing element 20 can be a highlighter, marker, ball point pen,
roller
ball pen, felt-tipped pen, fountain pen, or any other type of writing element
using a fluid-
based writing medium. In other embodiments, inner writing element 20 can be a
pencil,
stylus, chalk, charcoal, lead, or any other type of writing element using a
solid-type writing
medium. If desired, in order to limit the overall outer diameter of writing
instrument 10,
inner writing element 20 may be selected to have as small an outer diameter as
possible. In
such case, inner writing element 20 would generally not have a filler-type
writing medium
reservoir, as such reservoirs tend to occupy more space than a tube-type
writing medium
reservoir to hold a given amount of writing medium. For instance, any writing
element
utilizing a tubular reservoir for holding writing medium, or any solid-type
writing medium
may be used to keep the overall diameter of writing instrument 10 as close to
that of a
standard single-writing-element writing instrument. Preferably, such writing
element is
rigid or semi-rigid for purposes as will become apparent. For the sake of
convenience, such
writing elements are referenced herein as "structurally stable thin writing
elements," in
contrast with filler-type writing elements utilizing filler-type writing
medium reservoirs and
the like that result in bulky writing elements that cause an overall increase
in the outer
diameter of writing instrument 10 upon insertion within outer writing element
22. As used
herein, a filler-type writing medium reservoir is a writing medium reservoir
that contains
porous material (made of polymers (natural or synthetic), ceramics, metals, or
the like) for
holding a writing medium (such as within its pores) without allowing the
writing medium to
flow freely, yet allowing the writing medium to be extracted (such as by a
wick using
capillary forces) for application to a surface as desired. The pores can be
formed in any of a
variety of ways - such as by blow molding, by sintering, or by fiber bundling.
It will be
appreciated that these examples of writing elements are merely illustrative
and the present
invention is not necessarily limited thereto. It will further be appreciated
that the term
"writing medium" is used for the sake of convenience and is not intended to
limit the
"writing element" to specifically "writing" operations, as the invention is
not limited to
"writing" operations, as noted above.
[0035] In the embodiment of FIG. 2, inner writing element 20 is formed from
two
distinct members - first writing tip 30 and first writing medium reservoir 28.
It should be
appreciated, however, that writing tip 30 and first writing medium reservoir
28 can be one
unitary, monolithic piece. In a preferred embodiment, first writing tip 30 of
inner writing
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element 20 is in direct operative contact with first writing medium reservoir
28 when a
fluid-based writing medium is used.
[0036] First writing medium reservoir 28 can be a writing medium tube or ink
tube
(i.e., hollow tube capable of holding ink), such as those known in the art.
Unlike a filler-
type writing medium reservoir, which is also generally known in the art, the
writing
medium tube has no filler material for holding writing medium. Nonetheless,
the first
writing medium reservoir 28 can also be a filler-type writing medium reservoir
(not shown)
- e.g., filler material saturated with marking medium.
[0037] In one embodiment, outer writing element 22 has two distinct members -
second writing tip 32 and second writing medium reservoir 34. Moreover, second
writing
tip 32 may be in direct operative contact with second writing medium reservoir
34. It
should be noted that second writing tip 32 and second writing medium reservoir
34 can be
one unitary piece instead. In the embodiment of FIG. 2, outer writing element
22 has an
inner axial passage 24 therethrough - preferably through second writing tip 32
and second
writing medium reservoir 34. To facilitate insertion of inner writing element
20 through
outer writing element 22, second writing medium reservoir 34 preferably is a
filler-type
reservoir having a filler material (not shown) for holding writing medium. The
filler may
be made of a material such as polyester, acrylic, acetate, and may have a
porosity of
approximately 80% and a fiber density of approximately 0.18 gr/cm3. The
porosity,
however, can be as low as approximately 75% or can be as high as approximately
95%, and
the fiber density can be as low as approximately 0.16 gr/cm3 or as high as
approximately 0.2
gr/ cm3. Specifically, the filler may comprise polyester, acrylic, or acetate
fibers -- such as
available from De Martini SPA (Via Santuario d'Oropa, Italy) or Filtrona
(London,
England) -- or a bicomponent fiber (e.g., containing both polypropylene and
polyethylene),
such as available from Filtrona. Various factors such as cost, density,
porosity, chemical
stability, amount of time for the filler material to dry out, and ease of
manufacturing may be
considered when selecting materials that may be used for the filler. Second
writing medium
reservoir 34 may, however, also be filler-less - similar to a writing medium
tube. In one
embodiment, the outer writing element can be a highlighter or marker. But,
other writing
elements may be used instead.
[0038] Second writing tip 32 preferably is formed and configured to have a
wall
thickness thick enough to permit formation of an inner axial passage 24
therethrough
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without collapsing during writing. Also, second writing tip 32 should be
formed so that a
consistent line may be drawn each time it is used.
[0039] Preferably, second writing tip 32 may be a porous nib. As used herein,
a
"porous nib" is a deflection-resistant porous application tip that is
typically rod-shaped, with
a pointed or chiseled free end, and that delivers writing medium from a
reservoir to a
surface (e.g., paper), typically by capillary action. The porous nib may be
formed from any
desired porous material, such as polymers (natural or synthetic) or ceramics,
using
conventional forming processes such as sintering, blow molding, extrusion,
fiber bundling,
or the like. Such porous nib is thus distinguished from solid-type writing
mediums (as
defined above) and other non-porous nibs, such as fountain pen nibs, roller-
ball points, and
ball-points, or other such writing tips or nibs in which the writing medium
flows over or
around the exterior of the writing tip and onto the application substrate. A
porous nib-type
element may include, but is not limited to, highlighter, marker, or felt-
tipped nibs. Such
porous nibs are typically relatively wider than other writing tips, and are
not used for fine,
detailed writing, and may be chiseled to permit marking of wide lines. As a
porous nib,
second writing tip 32 may be made of, for example, sintered polyethylene
powder or
polyester fibers, having a porosity of approximately 50%, such as sold by
Porex Products,
of Fairburn, Georgia. The porous nib can also be made of acrylic or polyamide
(e.g.,
Nylon) fibers having a porosity of approximately 60%; however, a porosity as
low as
approximately 50% or as high as approximately 70% may also be used. A
polyester fiber
porous nib, such as sold by Teibow or Aubex (both of Japan) may be used,
instead, to
provide a potentially longer cap-off time (i.e., allowing reduction in
evaporation of writing
medium). The fiber density of the porous nib can be as low as approximately
0.1 gr/cm3 or
as high as approximately 0.3 gr/ cm3. Moreover, the density may vary, if
desired, along the
longitudinal axis. For instance, a higher density at the writing end may be
desirable to
prevent wobble. It should be noted, however, that while a lower density may be
better for
immediate ink flow (i.e., the initial ink flow at about the time the writing
element contacts a
writing surface), it is not necessarily better for total ink flow (i.e., the
ink flow over the
entire time the writing element is in use). Nevertheless, both wobble and ink
flow can be
taken into consideration when deciding on the density of the nib material.
Moreover,
various factors, such as cost, strength, rigidity, density, porosity, chemical
stability (e.g.,
resistance to corrosion or break-down of writing medium or components in
contact with
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writing medium), amount of time for the nib material to dry out, and ease of
manufacturing
may be considered when selecting materials that may be used for the porous
nib.
[0040] As illustrated in both FIGS. 5 and 6, distal porous nib portion 33 may
have
different profiles. For example, distal porous nib portion 33 can be angular
or straight. The
angle 35 between a writing surface (not shown) and distal porous nib portion
33 is known as
the angle of the chisel, which can be any angle typically approximately more
than 0° or
typically approximately less than 90° (0° forming a straight
distal porous nib portion 33, as
illustrated in FIG. 5, and 90° forming a flat distal porous nib portion
(not shown)). A
preferred exemplary angle of distal porous nib portion 33 is approximately
30°. Moreover,
second writing tip 32 may have a cross-section that is round, square, conical,
frustroconical,
etc. Such profiles and cross-sections are only illustrative and do not limit
the range of
possible profiles and/or cross-sections. Preferably, distal porous nib portion
33 is shaped
and configured (e.g., by selecting an appropriate angle and thickness) to
permit uniform
marking without a "railroad" effect such as two lines with no marking
therebetween.
[0041] As shown in FIGS. 5 and 6, second writing tip 32 can have various
connection components. For example, second writing tip 32 may have one or more
prongs
40 extending therefrom to engage second writing medium reservoir 34. In
another
embodiment, second writing tip 32 may use open-ended cylinder 42 for engaging
second
writing medium reservoir 34.
[0042] In the embodiments, shown in FIGS. 7 and 8, at least a portion of outer
writing element 22 may have a circular cross-section 49 or non-circulax (e.g.,
oval) cross-
section 50, and inner diameter 54, 56 (respectively) of outer writing element
22 has a
circular cross-section. In another embodiment, not shown, at least a portion
of inner writing
element 20 may have a non-circular (e.g., oval) cross-section. The cross-
section of outer
writing element 22 may be selected to provide improved resistance to flexure
or wobble
(i.e., the bend of a writing element that occurs during writing) as compared
to a writing
element with an inner axial passage and a circular cross-section. A circular
inner diameter
54, 56 allows for ease in axial movement of writing elements 20, 22 with
respect to each
other. Nevertheless, in another embodiment, inner diameter 54, 56 may be oval
or another
shape.
[0043] While one reservoir can be used to supply writing medium to both
writing
elements 20, 22, it is desirable for second writing medium reservoir 34 to be
sepaxate and
to
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distinct from first writing medium reservoir 28. In this way, reservoirs 28,
34 can contain
different writing mediums or exhibit different characteristics, such as
different colors.
[0044] It should be noted that first and second writing medium reservoirs 28,
34
may be selected to have a writing capacity not significantly lower than that
of a writing
instrument with a single writing element having the same type of writing
medium reservoir.
For example, if inner writing element 20 is a ball point pen and outer writing
element 22 is a
highlighter, inner writing element 20 and outer writing element 22 preferably
have the same
writing capacity as a standard ball-point and a standard highlighter,
respectively. A
ballpoint pen according to current industry standards can draw a line
approximately 1800
meters in length; a highlighter according to current industry standards can
draw a line
approximately 120 meters in length. Because outer writing element 22 loses
valuable space
to inner axial passage 24, such a requirement affects the maximum desirable
outer diameter
of outer writing element 22, and consequently, the maximum desirable outer
diameter of
writing instrument 10. The writing capacity may be optimized while keeping the
reservoirs
within the desired size limitations by manipulating various factors, such as
the combination
of materials making up the outer writing element, the wall thicknesses of the
elements, and
overall dimensions of the pen. Based on average usage of ball point pen and
highlighters, a
writing capacity ratio of approximately 10:1 is desirable -- i.e., preferably,
writing
instrument 10 provides approximately 10 meters of ball point pen line for
every
approximately 1 meter of highlighter line. It will be appreciated that the
desired reservoir
capacity may be affected by the desired outer diameter and/or length of the
finished writing
instrument, and other such factors appreciated by those of skill in the art.
[0045] In order to operate writing instrument 10, it is desirable to have a
driving
mechanism operatively connected to at least one writing element 20, 22 for
moving the at
least one writing element 20, 22 with respect to the other writing element 20,
22. The
driving mechanism can be actuated by moving at least a portion of or another
component
coupled to the driving mechanism. Upon actuation of the driving mechanism, a
desired
writing element is extended into a use position. Such driving mechanism may be
actuated
by twisting (i.e., a twist-actuated driving mechanism) a portion of writing
instrument 10 or
an element connected thereto, or by pushing a pushbutton actuator axially
along the
longitudinal axis of writing instrument 10.
11
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[0046] One exemplary driving mechanism 60 is illustrated in FIG. 9. Driving
mechanism 60 includes two driving components -- a mobile, female cam 62 and an
axially
stationary male cam 64. It will be appreciated that interactions of various
components of
driving mechanism 60 with respect to components of writing instrument 10 are
applicable to
other driving mechanism embodiments described herein. Mobile cam 62 can be
made of
polyamide (e.g., Nylon) or polyacetal (e.g., Delrin), and male cam 64 can be
made of
polyacetal (e.g., Delrin). However, other materials can be used to make mobile
cam 62 and
male cam 64. Various factors such as strength, rigidity, and lubricity (i.e.,
smoothness) may
be considered when selecting materials that may be used for cams 62 and 64. In
general,
one writing element 20, 22 may be coupled to mobile cam 62 and the other
writing element
20, 22 can be coupled to male cam 64, as described in further detail below.
Male cam 64
can be inserted in bore 63 at proximal end 65 of mobile cam 62. While other
methods of
insertion are possible, in the illustrated configuration of cams 62, 64,
insertion may be
accomplished by inserting male cam 64 into bore 63 at an angle (e.g.,
approximately 35° to
approximately 45°) and then straightening male cam 64 as it is further
inserted into mobile
cam 62. Male cam 64 has pin 68, which can be fitted into helical cam slot 66
of mobile cam
62.
[0047] In one embodiment of the present invention, driving mechanism 60
operates
to move outer writing element 22 with respect to inner writing element 20.
Inner writing
element 20 may be fixed with respect to outer barrel 12, or may be arranged
for axial
movement as well. In such embodiment, outer writing element 22 can be
operatively
coupled to mobile cam 62 and inner writing element 20 may be coupled to male
cam 64 or
outer barrel 12. Outer writing element 22 can be held by longitudinal ribs
(not shown) in
mobile cam 62. For example, if outer writing element 22 comprises a filler-
type writing
medium reservoir, the longitudinal ribs can cut into the filler-type writing
medium reservoir
and/or filler material. Proximal end 73 (FIG. 2) of inner writing element 20
can be inserted
into a bore (not shown) in male cam 64 or may be coupled to outer barrel 12 in
another
manner to permit axial movement with respect to outer writing element 22.
Inner writing
element 20 may be arranged in male cam 64 so that proximal end 73 of inner
writing
element 20 does not extend past male cam 64.
[0048] Furthermore, an optional biasing element, such as a coil spring 61
(FIG. 3),
can be positioned around second writing tip 32 between shoulder 37 (FIGS. 3, 5
and 6) of
second writing tip 32 and front nose cone 23. Thus, outer writing element 22
can be pushed
12
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back into mobile cam 62. It will be appreciated that when outer writing
element 22 is
extended into a writing or marking position, spring 61 is compressed. When
compressed,
spring 61 essentially functions as an outer tubular support for second writing
tip 32. The
provision of a spring thus adds structural stability to second writing tip 32,
and thereby
further addresses the desire to assure that a hollow writing tip 32 is
sufficiently structurally
stable to write or mark effectively. Moreover, by pressing outer writing
element 22 into
mobile cam 62, spring 61 inhibits if not prevents loosening andlor separation
of outer
writing element 22 and mobile cam 62 if, for example, writing instrument 10 is
impacted,
such as by falling/dropping and outer writing element 22 hits a surface (e.g.,
a floor, table,
etc.). Various factors such as strength and chemical stability can be
considered when
selecting the material to be used for spring 61. For instance, spring 61 can
be made of 316
stainless steel or any other suitable material. Moreover, spring 61 should be
flexible enough
to allow for operation of driving mechanism 60, while being strong enough to
hold outer
writing element 22 in mobile cam 62. Additionally, there may an O-ring (not
shown)
around second writing tip 32 between second writing tip 32 and front nose cone
23. Such a
construction could prevent/reduce the evaporation of writing medium.
[0049] In one embodiment, male cam 64 may be fixed to back barrel 16 so that
rotation of back barrel 16 causes rotation of male cam 64 (preferably
generally
corresponding to the rotation of back barrel 16) without causing axial
movement of male
cam 64. While male cam 64 can be fixed to back barrel 16 in numerous ways, in
the
embodiment of FIG. 9, insertion member 70 can be press-fitted into inner
receiving
member 29 (FIG. 4). Engaging flats 169 may be provided on male cam 64 to
engage back
barrel receiving flats 69 (FIG. 4). As described in greater detail below,
FIG.16 illustrates
another embodiment in which a male cam 364 is fixed to back barrel 316 by
engaging
protrusions 385 in notches 386, and by engaging flats 369 in back barrel
receiving flats 391.
Mobile cam 62, 362 is free to move with respect to back barrel 16, 316. Mobile
cam 62,
362 is also free to move axially, but not rotationally, with respect to front
barrel 14 to
extend or to retract a writing element 20, 22.
[0050] In operation, in the embodiment of FIGS. 3 and 9, rotation of back
barrel 16
(or any other component coupled to driving mechanism 60) causes rotation of
male cam 64
(preferably generally corresponding to the rotation of back barrel 16) and,
consequently,
rotation of pin 68 in cam slot 66. Because mobile cam 62 is fixed against
rotational
movement, rotation of pin 68 in cam slot 66 results in axial movement of
mobile cam 62,
13
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and corresponding axial movement of one writing element 20, 22 with respect to
the other
writing element 20, 22. Thus, if mobile cam 62 and male cam 64 are moved
axially with
respect to each other, the writing elements 20, 22 respectively coupled
thereto also move
axially with respect to each other. Cam slot 66 may terminate in locking
notches 67 or the
like, in which pin 68 may be disposed to prevent further rotation of male cam
64. Locking
notches 67 are extensions of cam slot 66 extending substantially perpendicular
to
longitudinal axis 11 (FIG.1). Thus, locking notches 67 may retain moveable
writing
element 20, 22 in an extended or a retracted position. Male cam 64 also may
have a radially
outwardly extending stopping section, such as in the form of stopping element
72, which
effectively increases the outer diameter of male cam 64, thereby preventing
male cam 64
from moving too far into mobile cam 62 once proximal end 65 contacts the
stopping
element 72. However, it is possible that pin 68 might reach the end of slot 66
at
substantially the same time that stopping element 72 contacts mobile cam 62.
When pin 68
reaches the end of slot 66 or stopping element 72 contacts proximal end 65 of
mobile cam
1 S 62, back barrel 16 can be turned no further, so that the writing element
20, 22 that is being
moved is fully extended and its distal end extends beyond (or in the same
plane as, if
desired) the distal end of the fixed writing element 20, 22.
[0051] To enable movement of inner and outer writing elements 20, 22 with
respect
to each other, driving mechanism 60 may be moveably coupled to front barrel
14. As
shown in FIG. 9, mobile cam 62 may have two prongs 173, 174, which engage
corresponding front barrel prongs 175,176, such that mobile cam 62 can move
axially, but
not rotationally, with respect to front barrel 14. Prongs 173, 174 and 175,
176 may be made
of the same material as cam 62 and front barrel 14, respectively. Various
factors such as
rigidity, strength, and ease of manufacturing may be considered when selecting
material to
be used for prongs 173,174,175 and 176. It will be appreciated that other
numbers and
configurations of prongs are within the scope of the invention. For example,
mobile cam 62
may have a single prong engaging a single prong receiving structure (not
shown) of front
barrel 14. Alternatively, front barrel 14 may have a single prong engaging a
single prong
receiving structure (not shown) of mobile cam 62. Moreover, for the driving
means 60
illustrated in FIG. 9, any means of attaching mobile cam 62 to front barrel 14
may be used.
Preferably, the configuration of the driving mechanism at least allows
movement of mobile
cam 62 along the axis of front barrel 14.
14
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[0052] In the embodiment of FIG. 9, prongs 173,174 on mobile cam 62 can be
provided with guides 177,178, respectively. Rail members 179,180 are provided
on front
barrel 14, such as on barrel prongs 175,176. Guides 177 may engage rail
members 179 and
guides 178 may engage rail members 180 such that mobile cam 62 can move
axially, but
not rotationally, with respect to front barrel 14. Upon rotation of back
barrel 16, male cam
64 rotates to move mobile cam 62 axially with respect to front barrel 14 in a
distal or
proximal direction. Consequently, guides 177,178 move along rail members
179,180.
Prongs 173,174,175, and 176 can be positioned between second writing medium
reservoir
34 (e.g., filler-type writing medium reservoir) and outer barrel 12. Thus,
prongs 173,174
and 175,176 will not disengage from one another and possibly break. It will be
appreciated
that configurations of mating elements other than those illustrated, but
formed to effect
movement of mobile cam 62, are within the scope of the present invention.
[0053] FIG. 10 illustrates an alternative prong mechanism. Driving mechanism
160
of FIG. 10 is similar to driving mechanism 60 of FIG. 9. As shown in FIG.10,
mobile
cam 162 may have two prongs 273, 274, which engage corresponding front barrel
prongs
275, 276, such that mobile cam 162 can move axially, but not rotationally,
with respect to
front barrel 14. Prongs 273, 274 and 275, 276 may be made of the same material
as cam
162 and front barrel 14, respectively. Various factors such as rigidity,
strength, and ease of
manufacturing may be considered when selecting material to be used for prongs
273, 274,
275, and 276. The material used for prongs 273, 274, 275, and 276, however,
preferably are
not brittle.
[0054] If desired, engaging elements may be provided to regulate the extent of
axial
movement of mobile cam 162. Such engaging elements may be used, for instance,
to
prevent over-extension of mobile cam 162. In the embodiment of FIG.10, at
least one of
prongs 273, 274 on mobile cam 162 may be provided with protrusions 277, and
front barrel
14 may be provided with receiving members 278, 279, such as on barrel prongs
275, 276.
In the retracted position of mobile cam 162, protrusions 277 engage first
group of receiving
members 278 at a proximal end 281 of front barrel prongs 275, 276. Upon
rotation of back
barrel 16, male cam 164 rotates to move mobile cam 162 axially with respect to
front barrel
14 in a distal direction 282. Consequently, protrusions 277 disengage first
group of
receiving members 278 and, once mobile cam 162 has moved axially to extend one
of
writing elements 20, 22, protrusions 277 engage second group of receiving
members 279.
Such engagement stops further extension of the at least one writing element
20, 22 beyond
is
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the other writing element 20, 22. It will be appreciated that configurations
of engaging
elements other than those illustrated, but formed to effect movement of mobile
cam 162, are
within the scope of the present invention.
[0055] In an alternative embodiment illustrated in FIG.11, exemplary driving
mechanism 260 includes a mobile, female cam 262 and male cam 264. Driving
mechanism
260 may work much like driving mechanism 60 or 160 to accomplish a similar
result. Male
cam 264 can be inserted in bore 263 at proximal end 265 of mobile cam 262.
While other
methods of insertion are within the scope of the present invention, insertion
may be
accomplished by inserting male cam 264 at an angle (e.g., approximately
35° to
approximately 45°) with respect to female cam 262 and then
straightening male cam 264 as
it is further inserted into female cam 262. Male cam 264 has pin 268 that can
be fitted into
helical cam slot 266 of mobile cam 262. Cam slot 266 may terminate in locking
notches
267 (similar to above-described locking notches 67) or the like, in which pin
268 may be
disposed to prevent further relative rotation of male cam 264 and mobile cam
262 and to
prevent further axial movement of mobile cam 262. This may provide a means of
locking a
moveable writing element 20, 22 into an extended or retracted position. Male
cam 264 also
may have a stopping section, such as in the form of stopping ribs 272, which
effectively
increase the outer diameter of male cam 264, thereby preventing male cam 264
from
moving into mobile cam 262 once proximal end 265 contacts stopping ribs 272.
However,
it is possible that pin 268 might reach the end of slot 266 at substantially
the same time that
stopping ribs 272 contact mobile cam 262. While male cam 264 can be fixed to
back barrel
16 in numerous ways, insertion member 270 can be press-fitted into inner
receiving member
29 (FIG. 4). Engaging flats 269 may also be provided on male cam 264 to engage
back
barrel receiving flats 69 (FIG. 4) to fix male cam 264 to back barrel 16.
(0056] In one embodiment of the present invention, driving mechanism 260
operates
to move outer writing element 22 with respect to inner writing element 20.
Inner writing
element 20 may be fixed with respect to outer barrel 12, or may be arranged
for axial
movement as well. In such embodiment, outer writing element 22 can be
operatively
coupled to mobile cam 262 and inner writing element 20 may be operatively
coupled to
male cam 264 or outer barrel 12. Outer writing element 22 can be held in
mobile cam 262
by longitudinal ribs 271 (shown in phantom in FIG.11). For example, if outer
writing
element 22 comprises a filler-type writing medium reservoir, ribs 271 can cut
into the filler-
type writing medium reservoir and/or filler material. Proximal end 73 (FIG. 2)
of inner
16
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writing element 20 can be inserted into a bore (not shown) in male cam 264 or
may be
operatively coupled to outer barrel 12 in another manner to permit axial
movement with
respect to outer writing element 22. Inner writing element 20 may be arranged
in male cam
264 so that proximal end 73 of inner writing element 20 does not extend past
male cam 264.
[0057] To enable movement of inner and outer writing instruments 20, 22 with
respect to each other, driving mechanism 260 may be moveably coupled to front
barrel 14.
For example, non-circular cross-section 50 (e.g., oval) (FIG. 8) of outer
writing element 22
may contact outer barrel 12. Cross-section 50 would allow for axial, but not
rotational
movement of mobile cam 262 and outer writing element 22 in an embodiment where
the
inner surface of front barrel 12 has a non-circular cross-section as well. It
should be noted,
however, that any other manner of preventing rotation of mobile cam 262 with
respect to
front barrel 14 may be implemented as well. Thus, rotation of back barrel 16
(or a portion
of outer barrel 12 connected to driving mechanism 260) rotates male cam 264,
causing pin
268 to move in slot 266 in a helical direction. Even though mobile cam 262 may
be
constrained against rotational movement, mobile cam 262 can still move
axially. This
results in axial movement of writing elements 20, 22 with respect to each
other.
[0058] FIG.12 shows another embodiment of a driving mechanism 460 with
exemplary writing elements 20, 22. I?riving mechanism 460 is made up of cam
402,
counter-cam 404, and cartridge closure 406 having cam follower 408 preferably
formed
thereon. While cam 402 and counter-cam 404 are shown as two separate pieces,
it should
be noted that they can be a single, composite piece. Cam 402 and counter-cam
404 may be
formed as a single piece hinged together, thus allowing cam 402 and counter-
cam 404 to
open like a clam shell. Cartridge closure 406 with cam follower 408 are
inserted over
proximal end 409 of outer writing element 22, and may be in the form of a clam
shell to
facilitate such insertion. Cam 402 and/or counter-cam 404 can be closed around
cartridge
closure 406. Specifically, cam follower 408 can be inserted in helical
caroming slot 410
(i.e., the space between cam 402 and counter-cam 404). Alternatively,
cartridge closure 406
and cam follower 408 may be force-fitted into cam 402 and/or counter-cam 404.
[0059] Cam 402, counter-cam 404, and inner writing element 20 may be fixed
against axial and rotational movement with respect to back barrel 416. As
shown in FIG.
12, fixing of cam 402 and counter-cam 404 can be accomplished by the mating of
longitudinal back ribs 412 in back barrel 416 and cam grooves 415 in cam 402
and counter-
cam 404. Outer writing element 22 is free to move axially, but not
rotationally, along
17
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longitudinal front ribs 420. Since cartridge closure 406 with cam follower 408
may be fixed
to outer writing element 22, it may also be free to move axially.
[0060] The embodiment of FIG.12 can also have a cartridge case 418 for guiding
the movement of outer writing element 22. Cartridge case 418 may be made from
polypropylene, polyethylene, nylon, or any other suitable material. Cartridge
case 418 may
have grooves 419 receiving longitudinal front ribs 420 of front barrel 414.
Rotation of back
barrel 416 (or any portion of outer barrel 12 connected to driving mechanism
460) rotates
caro 402 and counter-cam 404, which, in turn, causes cam follower 408 to move
along
caroming slot 410. The movement of cam follower 408 translates to axial
movement of
cartridge closure 406. Thus, while inner writing element 20 remains
stationary, outer
writing element 22 moves axially with respect thereto. Grooves 419 guide axial
movement
of outer writing element 22 by groove 419 moving along longitudinal front ribs
420.
[0061] Yet another exemplary driving mechanism 560 is illustrated in FIG. 13.
Driving mechanism 560 may be positioned in outer barrel 512. Driving mechanism
560
includes a stationary cam 564 in the form of a spinner with a helical cam
surface 580
(similar to those used in twist-actuated retractable writing instruments), and
mobile cam 562
in the form of a follower having a cam follower protrusion 582 that rides
along helical cam
surface 580. Cam follower protrusion 582 is fixed against rotational movement
with respect
to outer barrel 512 by being held within a slit 584 in bushing 586 in which
mobile cam 562
is positioned. Thus, rotation of outer barrel 512 causes rotation of
stationary cam 564
which, in turn, causes cam follower protrusion 582 to ride along helical cam
surface 580
and thus to move axially along slit 584. A writing element 20, 22 rests
against a plug 587 at
distal end 588 of mobile cam 562 and is thereby retracted or extended as
stationary cam 564
is rotated. In the embodiment of FIG.13, stationary cam 564 is different from
prior art
spinners in that a recess 589 is formed therein to hold inner writing element
20 (and, more
specifically, first writing medium reservoir 28). Outer writing element 22
abuts plug 587 to
move axially therewith with axial movement of mobile cam 562. A spring 561,
which is
positioned between front nose cone 592 and shoulder 594 of outer writing
element 22,
pushes outer writing element 22 against plug 587 (i.e., spring 561 keeps plug
587 in
continuous contact with outer writing element 22). Spring 561 may also keep
follower
protrusion 582 in contact with helical cam surface 580. Keeping contact
between protrusion
582 and cam surface 580 enables proper operation of driving mechanism 560,
such as for
reasons described above with respect to spring 61.
is
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[0062] Driving mechanisms 60, 160, 260, 460, 560 can be actuated by moving
(e.g.,
axially or rotatably) a component making up or coupled to driving mechanisms
60,160,
260, 460, 560 as described above. Upon actuation of any of driving mechanisms
60,160,
260, 460, 560, the moveable writing element is extended from outer barrel 12
so that its
distal-most portion extends beyond the distal-most portion of the fixed
writing element 20,
22. Therefore, the moveable writing element can be used to mark a surface.
Thus, driving
mechanisms 60, 160, 260, 460, 560 permit selection of a desired writing
element 20, 22,
with a simple operation. Driving mechanisms 60,160, 260, 460, 560 enable a
user to use
one writing element 20, 22 one at a time or even at the same time if desired.
[0063] As shown in FIG. 3, in an embodiment in which driving mechanism 60,160,
260, 460, 560 is actuated by movement of outer barrel 12 (or a portion
thereof), front barrel
proximal portion 21 may be coupled to back barrel distal portion 18 so as to
permit relative
rotational movement of barrels 14,16, while inhibiting relative axial
movement. To prevent
front barrel 14 and back barrel 16 from separating, front barrel 14 may have
external
circumferential ribs 15. Moreover, as shown in FIG. 3, and more clearly in
FIG. 4, back
barrel 16 may have internal circumferential ribs 17. It is desirable that ribs
15,17 are
positioned to prevent axial movement of barrels 14,16, with respect to each
other, while
still allowing for rotational movement of barrels 14,16 with respect to each
other. To
accomplish this, each external circumferential rib 15 may be positioned
adjacent to an
internal circumferential rib 17. In the one embodiment, at least one external
rib 15 can be
positioned between two internal ribs 17. Or, at least one internal rib 17 can
be positioned
between two external ribs 15. Such a configuration prevents front barrel 14
and back barrel
16 from moving apart. Additionally, an O-ring (not shown) may be positioned
inside back
barrel distal portion 18 (other locations are also contemplated). An O-ring
can provide
smooth movement of barrels 14,16 relative to each other and help prevent
evaporation of
writing medium (v.e., prevent writing elements 20, 22 from drying out). For
instance, back
barrel 16 can have a pair of internal circumferential ribs 17 with an O-ring
or one
circumferential rib 17 with an O-ring. The O-ring may be made of silicon
rubber or any
other suitable material. Various factors -- for example, ability to provide a
good seal and
smooth movement between front and back barrel 14,16 -- can be considered when
selecting
a suitable material to be used for the O-ring. Moreover, rib 19 (FIG. 3) may
be provided on
front barrel proximal portion 21 to abut back barrel distal portion 18 and
thus to inhibit
excessive distal movement of back barrel 16. It should be noted that a writing
instrument
19
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cover (for example, cap 90 or 290 shown in FIG.14 and 15, respectively, and
described in
further detail below) may engage rib 19 so that the writing instrument cover
is held over the
distal writing end of writing instrument 10.
[0064] Exemplary driving mechanism 60,160, 260, 460, 560 may be located at
proximal end 43 or distal end 41 of writing instrument 10 (FIG.1), or anywhere
in between.
Preferably, the driving mechanism 60, 160, 260, 460, 560 is located at
proximal end 43 of
writing instrument 10 so as not to interfere with the components and
arrangement of writing
elements 20, 22. Driving mechanism 60, 160, 260, 460, 560 or components
thereof, may be
directly accessible for actuation, for example, either by an opening in outer
barrel 12 or by
driving mechanism 60, 160, 260, 460, 560 not being covered by an outer barrel
12 at all. At
least one writing element 20, 22 can be operatively coupled to driving
mechanism 60, 160,
260, 460, 560. The other writing element 20, 22 is arranged to be movable
independently of
the at least one writing element connected to driving mechanism 60,160, 260,
460, 560 and
may be connected, for example, to outer barrel 12. In another embodiment, both
writing
elements 20, 22 can be connected to driving mechanism 60, 160, 260, 460, 560.
It should
be noted that neither writing element 20, 22 has to be directly connected to
the driving
mechanism 60,160, 260, 460, 560. Preferably, there are no intermediary
elements (not
shown) connecting the driving mechanism 60,160, 260, 460, 560 to one or both
writing
elements 20, 22.
[0065] Returning to writing elements 20, 22, since inner writing element 20 is
mounted within outer writing element 22, inner writing element 20 is further
(radially) from
outer barrel 12, and, further (radially) from the distal opening in front nose
cone 23 than in
standard writing instruments. In one embodiment, front nose cone 23 may be
made of a
clear material, such as for aesthetic purposes. By using a clear material, the
gap between
outer writing element 22 and front nose cone 23 is not so readily apparent.
Nevertheless,
front nose cone 23 and, for that matter, any other part of writing instrument
10 can be made
of clear material so that one can see the inner workings of writing instrument
10. Front
nose cone 23 can be made of polypropylene or other plastic or polymer. The
material
chosen for front nose cone 23 may be selected, for example, based on cost,
ease of
manufacturing, and resistance to vapor transmission or air-tightness.
[0066] Moreover, in one embodiment, in order to allow for axial movement of
writing elements 20, 22 with respect to each other, outer writing element 22
has an inner
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axial passage 24 (FIG. 2) that is larger than the outer diameter of inner
writing element 20.
Such a configuration can result in wobbling. Accordingly, it is desirable to
address any
resultant increased wobble. Individually, or in combination, rigidity of inner
writing
element 20 and the support provided by outer writing element 22 thus are
preferably
selected to minimize wobbling. While inner writing element 20 may obtain some
support
from inner axial passage 24 of outer writing element 22, outer writing element
22 may
provide only minimal stabilization to counter wobbling. Therefore, it is
generally desirable
to exhibit care in selecting the rigidity of writing elements 20, 22.
[0067] Rigidity may be a function of various characteristics, such as wall
thickness
or material. Ideally, inner writing element 20 has an outer diameter small
enough to fit
within inner axial passage 24 of outer writing element 22 and, at the same
time, a wall
thickness such that inner writing element 20 can hold a sufficient quantity of
writing
medium. Such factors may influence the choice of material used for inner
writing element
20. The material can be metal and/or plastic. Moreover, first writing
reservoir 28 can be
formed from a material different from the material of first writing tip 30. In
one
embodiment, first writing medium reservoir 28 and first writing tip 30 are
made of plastic.
For maximum stability of inner writing element 20, and to impart stability to
outer writing
element 22 as well, first writing medium reservoir 28 may be formed of metal.
Other
combinations of materials than those described herein may be used. Also, other
materials
presently known and those yet to be discovered may be used instead. Similarly,
composite
materials (i.e., combination of two or more materials) may be employed.
[0065] Because inner writing element 20 may be in contact with outer writing
element 22, it will be appreciated that it may also be desirable to select a
material that is
resistant to corrosion especially when the outer writing element 22 has a
filler-type writing
medium reservoir. Resistance to corrosion is important because first writing
medium
reservoir 28 is positioned within inner axial passage 24. If inner axial
passage 24 is made of
a porous material that allows writing medium contained within outer writing
element 22 to
penetrate therethrough, the writing medium from outer writing element 22 may
come into
contact with the first writing medium reservoir 28. Over time, corrosion of
first writing
medium reservoir 28 could cause the writing medium within first writing medium
reservoir
28 to leak into outer writing element 22 and vice versa. Furthermore,
corrosion may affect
the performance of writing instrument 10 because of resultant writing medium
losses.
21
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[0069] Additionally or alternatively, inner axial passage 24 of outer writing
element
22 may have an internal sleeve (not shown), thereby reducing, if not
eliminating, the
concern with selection of corrosion resistant material. Such a sleeve may also
be helpful in
reducing, if not eliminating, wicking of writing medium from second writing
medium
reservoir 34, via inner axial passage 24, onto inner writing element 20. An
inner sleeve may
be provided in inner axial passage 24. The inner sleeve may be made of
polyproplylene
and can have a thickness of as little as approximately 0.1 mm or as great as
approximately
0.5 mm. Other materials and thicknesses, however, may be used. For instance,
if made of
polypropylene, the inner sleeve may have a thickness of at least approximately
0.4 mm or at
most approximately 1 mm. The inner sleeve may also be made of any shrinkable
thermoplastic material, such as PET (polyethylene terephtalate), in which
case, the
thickness of the inner sleeve could be at least approximately 0.05 mm or at
most
approximately 0.8 mm. Various factors such as rigidity, chemical stability,
and ease of
manufacturing may be considered when selecting materials that may be used for
the inner
sleeve.
[0070] The minimum and maximum thicknesses of an inner sleeve formed of
polypropylene are a function of the extrusion process and writing capacity,
respectively. A
thickness of approximately 0.4 mm is the minimum thickness which typically can
be
extruded. Therefore, it is possible that the minimum thickness could be less
than 0.4 mm,
depending on the manufacturing process and other relevant factors, as long as
the sleeve is
still able to perform its above-stated functions. Moreover, the maximum
thickness could be
greater than 1 mm. However, it will be appreciated that the use of an inner
sleeve or
increasing the thickness of an inner sleeve may affect various characteristics
of the other
components of writing instrument 10, such as the dimensions of elements. For
example,
altering the dimensions of outer writing element 22 may affect the capacity of
outer writing
element 22 to hold writing medium. In order to maintain the capacity of outer
writing
element 22 (i.e., the amount of writing medium held therein), various changes
to writing
instrument 10 could be made, to compensate for the presences of an inner
sleeve or
increased thickness of the inner sleeve (e.g., increasing the outer diameter
or decreasing the
wall thickness of outer barrel 12, or decreasing the thickness of an outer
sleeve 80 (FIGS. 3,
5 and 6) discussed below).
[0071] Outer writing element 22 may comprise a porous nib and a filler-type
writing
medium reservoir, which includes a filler material surrounded by a filler
wrap. A filler
22
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wrap, such as filler wrap 78, may be typically designed to maintain rigidity
(i.e., by
preventing side walls of second writing medium reservoir 34 from collapsing
when
squeezed) and straightness (i.e., by allowing for smooth movement of outer
writing element
22 within writing instrument 10). Filler wrap 78 may also function to hold
filler material
inside filler wrap 78. In addition, filler wrap 78 may act as a barrier,
preventing writing
medium from passing therethrough and getting on a user's hands and/or fingers.
Filler wrap
78 may be made of polyethylene, polypropylene, polyamide (e.g., Nylon),
polyester, or
acetate and may have a minimum thickness of approximately 0.01 mm or a maximum
thickness, which can be a function of the amount of space available within
writing
instrument 10 and manufacturing constraints. Various factors such as rigidity,
chemical
stability, and ease of manufacturing may be considered when selecting
materials to be used.
A sleeve, or other type of coating, may also be provided on the outer surface
of outer
writing element 22 (particularly if outer writing element 22 has a filler-type
writing medium
reservoir) to prevent leakage, inadvertent marking, andlor evaporation of the
writing
medium therein.
[0072] Referring now to FIG. 3, at least an outer portion of outer writing
element 22
may be covered by sleeve 80, which can be non-porous or fluid-impervious (or
at least
specifically impervious to writing medium). When sleeve 80 is non-porous or
fluid-
impervious, sleeve 80 can protect the user from getting writing or marking
medium on
his/her hands and/or fingers when manipulating outer writing element 22.
Further, when
outer writing element 22 comprises a filler-type writing medium reservoir as
shown in FIG.
2, at least a portion of filler wrap 78 may be covered by sleeve 80 (FIG. 3).
As shown in
FIGS. 3, 5 and 6, sleeve 80 may also cover a portion of second writing tip 32
(particularly if
in the form of a porous nib). Such construction prevents evaporation of
writing medium
(because less surface area of second writing tip 32 is exposed to air) and,
thus, extends the
life - both shelf life and usage life - of outer writing element 22. Moreover,
as illustrated in
FIG. 5 and 6, sleeve 80 may also be provided over second writing tip 32
(particularly if in
the form of a porous nib) and may act as a coupling member, such as to hold
second writing
tip 32 and second writing medium reservoir 34 together. The use of sleeve 80
thus allows
for and facilitates refill of outer writing element 22 by joining second
writing tip 32 and
second writing medium reservoir 34 into a single component or unit. However,
any
structure or material that holds second writing tip 32 together with second
writing medium
reservoir 34 is envisioned -- for example, a stainless steel or plastic peg or
ring within tip 32
23
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and/or reservoir 34; a clip or ring crimped, squeezed, or glued around tip 32
and reservoir
34; or adhesive, staple, or any other fastener.
[0073] Sleeve 80 may be provided over the filler material, filler wrap 78,
andlor a
porous nib. Sleeve 80 may be made of a shrinkable thermoplastic material --
for example,
PET (polyethylene terephtalate), polyethylene polyamide (e.g., Nylon), or PVC
(polyvinal
chloride) -- or a polypropylene wrap. Various factors such as cost, strength,
chemical
stability, and ease of manufacturing may be considered when selecting material
to be used
for sleeve 80. If made of polypropylene, sleeve 80 may have a thickness of
approximately
0.5 mm; however, a thickness as small as approximately 0.4 mm or as large as
approximately 1.0 mm may be used. It will be appreciated that the thicker
sleeve 80 is, the
more like a structural element sleeve 80 becomes. Generally, it is desirable
to form sleeve
80 from a material that permits sleeve 80 to be as thin as possible so that
the presence of
sleeve 80 has an insignificant affect on the overall diameter of writing
instrument 10. More
preferably, sleeve 80 is only as thick as necessary to impart the desired
writing medium
imperviousness and/or impermeability and does not play a structural role other
than to hold
outer writing element 22 and second writing tip 32 together. In other words,
sleeve 80 may
be so thin that it is not a structurally stable element independently of outer
writing element
22, and merely provides a fluid barrier to filler-type writing medium
reservoir 34. Sleeve
80 may be flexible.
[0074] Thus, sleeve 80 may be in the form of a wrap material, such as a heat-
shrinkable sleeve, which permits formation of a sleeve with the smallest
achievable
thickness, thus contributing to maintaining a very small diameter for writing
instrument 10.
If made of PET, sleeve 80 may have a thickness of approximately 0.15 mm. The
minimum
thickness may be a function of the strength required to retain second writing
tip 32 in
second writing medium reservoir 34; the amount of available space in writing
instrument 10
to allow for free movement of the driving mechanism (i.e., no binding);
ability to
consistently shrink to a particular wall thickness; resistance to tearing or
splitting upon
shrinking; and speed at which shrinking can occur. For instance, the minimum
thickness
can be approximately 0.05 mm. The maximum thickness is generally dictated by
the
maximum thickness of writing instrument 10 and may be approximately 0.5 mm.
Another
benefit of a heat-shrinkable sleeve over an injection molded sleeve is that a
heat-shrinkable
sleeve facilitates assembly.
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[0075] In another embodiment, as illustrated in FIG.12, cartridge case 418 --
formed of a material that prevents seepage of writing medium therethrough -
may be
provided over the filler-type outer writing element 22 instead of a sleeve 80.
Sleeve 80 or
cartridge case 418 may hold second writing tip 32 and second writing medium
reservoir 34
together -- i.e., second writing tip 32 is attached to second writing medium
reservoir 34 and
sleeve 80 or cartridge case 418 is positioned therearound, thereby holding
these components
together. Other benefits of sleeve 80 and cartridge case 418 may include:
reduction in
evaporation of writing medium from outer writing element 22 and added
stability imparted
thereby to writing elements 20, 22. Additionally, sleeve 80 and cartridge case
418 allow for
clean and easy refill of outer writing element 22.
[0076] Refill may also be facilitated by constructing the above-described
writing
instrument to permit replacement of either writing element 20, 22. While prior
art devices
enable writing elements to be refilled (e.g., ball point pens, roller ball
pens), no prior art
device has allowed for refill of a porous nib-type writing element, or
combination porous
nib-type writing element and pen, pencil, marker, etc. The porous nib-type
writing element
can have a filler material (e.g., a filler-type writing medium reservoir)
holding writing
medium or may be fillerless (i.e., the ink is not contained in a filler
material). Therefore,
another feature of the present invention, independent of the above-described
features, is the
formation of a writing instrument with a porous nib-type writing element such
that the
porous nib-type writing element can be replaced when the writing medium
contained
therein is expended.
[0077] To enable replacement of one or both writing elements 20, 22, outer
barrel
12 preferably is formed to permit access to one or both writing elements 20,
22. Moreover,
writing elements 20, 22 are preferably removably positioned within outer
barrel 12 to
permit ready removal as desired. Access to writing elements 20, 22 can be at
either distal
end 41 or proximal end 43 of writing instrument 10. In the embodiment of FIG.1
and 3,
outer barrel 12 has a removable front nose cone 23 formed to permit access to
outer writing
element 22, thereby allowing removal and replacement of writing elements 20,
22. Front
nose cone 23 may have internal threads 27 to engage external thread 25 at the
distal end of
front barrel 14 so that front nose cone 23 can be threaded on and off front
barrel 14. Yet,
another embodiment may have both a removable front nose cone 23 and a
removable back
end button. Alternatively, front barrel 14 and back barrel 16 may be separable
to permit
access to writing elements 20, 22 therein.
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[0078] FIG.16 illustrates another replacement mechanism. Male cam 364 can
function with mobile cam 62,162, 262, 362 (shown as mobile cam 362) and end
button 380
to form a replacement mechanism, thereby simplifying refill of writing
elements 20, 22.
Male cam 364, with mobile cam 62,162, 262, 362 coupled thereto, can be
inserted into
back barrel 316, with engaging flats 369 engaging back barrel receiving flats
391 (FIG. 4).
End button 380 is configured to facilitate locking of male cam 364 with
respect to back
barrel 316. As internal threads 382 of end button 380 are screwed onto
external threads 381
of male cam 364, end button 380 is drawn closer to back barrel 316.
Simultaneously,
conical surface 383 pushes against cam inner surface 384, thereby pressing
engaging flats
369 tightly against back barrel 316 and preventing axial movement of male cam
364 with
respect to back barrel 316. To prevent rotational movement of male cam 364
relative to
back barrel 316 -- for example, during operation of writing instrument 10 --
and to allow for
end button 380 to be screwed thereon (i.e., keeping male cam 364 stationary
while button
380 is being screwed on), protrusions 385 slide into notches 386 in back
barrel 316. As end
button 380 is screwed further onto external thread 381, tapered surface 389 is
drawn into
back barrel 316, creating a preferably air-tight fit between back barrel 316,
male cam 364,
and end button 380. Rotation of end button 380 onto male cam 364 stops when
end button
engagement surface 387 contacts back barrel engagement surface 388.
Furthermore, male
cam 364 may further include a sealing ring 390 to create an air-tight seal
between male cam
364 and back barrel 316, thereby preventing the writing medium of writing
elements 20, 22
from evaporating. Such an air-tight seal is particularly important when one or
both of the
writing elements carries a volatile writing medium.
[0079] Using the replacement mechanism of FIG. 16, writing elements 20, 22 can
be replaced when the writing medium of writing element 20 andlor 22 is
expended. FIG.
17 illustrates one example of a refill set 400, which may include writing
elements 20, 22;
mobile cam 362; and male cam 364. It should be noted that mobile cam 362
andlor male
cam 364 can be reused while only writing elements 20, 22 are replaced.
[0080] If one of writing elements 20, 22 remains in an extended position
(i.e.,
writing tip 30 or 32 is not retractable into a position within outer barrel
12), or if at least one
of writing elements 20, 22 contains a volatile writing medium, it would be
desirable to
cover writing element 20, 22 to prevent evaporation of the volatile writing
medium. A cap
90 as illustrated in FIG. 14 may be used. Cap 90 can be made of ABS or
polypropylene
(but other materials are also envisioned). Various factors such as ability to
be welded or
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paintedldecorated, resistance to vapor transmission or air-tightness, cost,
and ease of
manufacturing may be considered in selecting material to be used. Cap opening
94 can be
placed over distal end 41 (FIG.1) of writing instrument 10 and may be fixed
thereto by
engaging rib 19 on front barrel 14 (FIG. 3). However, any similar structure
that adequately
covers writing elements 20, 22 can be used instead of cap 90. It should be
noted that a cap
may be purely ornamental and/or not for the purpose of preventing drying of
writing
medium. That is, there may be other reasons for a cap to be placed over
writing instrument
10. For instance, cap 90 may prevent breakage of first writing tip 30 or
second writing tip
32. Also, cap 90 may avoid inadvertent marking resulting by either writing tip
30, 32.
[0081] If, as described above, the writing medium of at least one of writing
elements
20, 22 is volatile, a vapor seal 92 preferably is provided within cap 90 to
prevent
evaporation of the writing medium. Vapor seal 92 can be placed within cap body
96 at a
location permitting ready secure coupling to outer barrel 12 to seal writing
elements 20, 22.
Vapor seal 92 may be designed to seal both first writing tip 30 and second
writing tip 32 by
engaging distal end 93 (FIG. 3) of front nose cone 23. In another embodiment,
vapor seal
92 may engage any distal portion of outer barrel 12.
[0082] While not necessary, clip 100 may also be provided on cap 90 so that
writing
instrument 10 may be attached to any object the user desires. Nevertheless,
other
attachment means may be used. Clip 100 may encircle vapor seal 92, contacting
cap body
96, and resting on cap support 194. Furthermore, clip 100 can be secured to
cap 90 by
being positioned between cap body 96 and top cap 102. While any means of
connected cap
body 96 and top cap 102 is envisioned, FIG.14 shows circumferential ribs 192
engaging
circumferential ribs 190 to hold cap body 96 and top cap 102 together.
[0083] Alternatively, cap 290 as illustrated in FIG.15 may be used. Cap 290
can be
made of ABS or polypropylene (but other materials are also envisioned).
Similar to cap 90,
various factors such as ability to be welded or paintedldecorated, resistance
to vapor
transmission or air-tightness, cost, and ease of manufacturing can be
considered in selecting
material to be used for cap 290. Cap opening 294 can be placed over distal end
41 of
writing instrument 10 and may be fixed thereto by engaging rib 19 on front
barrel 14 (FIG.
3). A vapor seal 292 may also be provided within cap 290 to prevent
evaporation of the
writing medium. Vapor seal 292 can be placed within cap body 296 at a location
permitting
ready secure coupling to outer barrel 12 to seal writing elements 20, 22.
Vapor seal 292
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may be designed to seal both first writing tip 30 and second writing tip 32 by
engaging
distal end 93 (FIG. 3) of front nose cone 23. In another embodiment, vapor
seal 292 may
engage any distal portion of outer barrel 12. Cap 290 may be formed with a
vent 298 and
an opening 204, which allow air to flow through cap body 296 to prevent
asphyxiation if
cap 290 is swallowed. A clip 200 may also be provided on cap so that writing
instrument
may be attached to any object the user desires. Clip 200 may encircle venting
means
298, contacting cap body 296. Furthermore, clip 200 can be secured to cap body
296 by
being positioned between cap body 296 and top cap 202.
[0084] While the foregoing description and drawings represent the preferred
10 embodiments of the present invention, it will be understood that various
additions,
modifications and substitutions may be made therein without departing from the
spirit and
scope of the present invention as defined in the accompanying claims. In
particular, it will
be clear to those skilled in the art that the present invention may be
embodied in other
specific forms, structures, arrangements, proportions, and with other
elements, materials,
and components, without departing from the spirit or essential characteristics
thereof. One
skilled in the art will appreciate that the invention may be used with many
modifications of
structure, arrangement, proportions, materials, and components and otherwise,
used in the
practice of the invention, which are particularly adapted to specific
environments and
operative requirements without departing from the principles of the present
invention. The
presently disclosed embodiments are therefore to be considered in all respects
as illustrative
and not restrictive, the scope of the invention being indicated by the
appended claims, and
not limited to the foregoing description.
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