Note: Descriptions are shown in the official language in which they were submitted.
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SHAVING CARTRIDGES HAVING LUBRICATION MEMBERS
FIELD OF THE INVENTION
The present invention relates to shaving razors and more particularly to
shaving razor
cartridges having a housing and a lubrication member secured to the housing.
BACKGROUND OF THE INVENTION
In general, shaving razors of the wet shave type include a cartridge or blade
unit with at
least one blade with a cutting edge, which is moved across the surface of the
skin being shaved
by means of a handle to which the cartridge is attached. The cartridge may be
mounted
detachably on the handle to enable the cartridge to be replaced by a fresh
cartridge when the
blade sharpness has diminished to an unsatisfactory level, or it may be
attached permanently to
the handle with the intention that the entire razor be discarded when the
blade or blades have
become dulled. Razor cartridges usually include a guard which contacts the
skin in front of the
blade(s) and a cap for contacting the skin behind the blade(s) during shaving.
The cap and guard
aid in establishing the so-called "shaving geometry", i.e., thc parameters
which determine the
blade orientation and position relative to the skin during shaving, which in
turn have a strong
influence on the shaving performance and efficacy of the razor. The guard may
be generally
rigid, for example formed integrally with a frame or platform structure which
provides a support
for the blades.
In the use of shaving razors of the wet shave type, factors such as frictional
drag of the
razor across the skin, force needed to sever hairs, and irritation or pre-
existing skin damage can
create a degree of shaving discomfort. Shaving aids, c.g., a lubricant,
whisker softener, razor
cleanser, medicinal agent, cosmetic agent or combination thereof, have been
incorporated into
razors, for exainple by incorporating a shaving aid into one or more extruded
or molded
polymeric components of the razor. Such shaving aid composites may be mounted
on the cap or
guard structures of the razor cartridge. Upon exposure to water, water-soluble
shaving aid
leaches from the composite onto the skin and the composite tends to swell.
The shaving aid composites must be positively secured for effective dispensing
throughout the useful shaving life of the razor. Forces during shaving may
contribute to
loosening of the shaving aid components from the cartridge. In addition,
consumers may store
the wet shaving cartridge on bathroom tub or countertop after shaving.
Accordingly, the wet
shaving aid components may become stuck to the bathroom tub or countertops.
The consumer
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inay then damage the shaving aid or the cartridge when attempting to remove
the cartridge from
the countertop or bathroom tub. Numerous extruded or molded shaving aid
components have
been developed which are secured to the shaving razor cartridge with
adhesives. These
arrangements have been unsatisfactory for certain applications. Adhesives are
typically a poor
choice for several reasons. Adhesives are difficult to work with from a
manufacturing
perspective and are also susceptible to changes in heat and humidity.
In certain countries, shaving razors are exposed to constant high levels of
heat and
humidity during shipment and storage. These levels of heat and humidity can
adversely affect
the adhesive properties such that the lubrication component is no longer
secured. Various press-
type designs have also been developed to secure the shaving aid component to
the cartridge of
the shaving razor. The various press-fit type designs have also proven to be
ineffective in certain
applications. Press-fit designs rely on a significant amount of force to be
applied to the shaving
aid composite in order to properly secure the shaving aid composite within the
housing, which
may cause the shaving aid composite to break or fracture. These designs are
also not very
effective because they do not accommodate for changing forces resulting from
the shaving aid
composite swelling and expanding. These cartridge designs also rely on an
increased surface
contact area with the shaving aid composite to better secure the shaving aid
composite to the
cartridge, which limits the cartridge design, such as the size of the
cartridge and the placement of
the blade(s).
What is needed, then, is a wet shaving razor cartridge having lubrication
member that is
secured to the cartridge that accounts for water absorption and swelling
without negatively
impacting shaving performance or the securement of the lubrication member to
the housing. It
may also be desirable to provide a manufacturing method for assembling a
lubrication member
that accounts for tolerance variations without negatively impacting shaving
performance. The
wet shaving razor cartridge assembly, is preferably simpler, cost-effective,
reliable, durable,
easier and/or faster to manufacture, and easier and/or faster to assemble with
more precision.
SUMMARY OF THE INVENTION
In one aspect, the invention features, in general, a shaving blade unit with a
housing
having a bottom surface and a top surface defining a pair of elongated spaced
apart apertures
extending from thc top surface to the bottom surface. At least one blade is
mounted to the
housing. The blade has a blade edge extending generally parallel to the pair
of apertures. A solid
polymeric lubrication member having an upper skin contact surface and an
opposing base. A pair
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protrusions extend from the base. Each protrusion has an enlarged distal end.
The enlarged distal
ends of the protrusions each have a dimension greater than a dimension of the
corresponding
aperture whereby inserting the protrusion into the corresponding aperture
deflects a front wall of
the housing and each of the enlarged distal ends engage the bottom surface of
the housing. The
enlarged distal ends of the protrusions are molded from a water soluble
polymer. If, desired,
particular embodiments may optionally include the solid polymeric lubrication
positioned within
a pocket defined by the front wall and a pair of internal sidewalls of the
housing. Particular
embodiments may also optionally include the pocket further defined by an
elastomerie member
positioned in front of the at least one blade.
In another aspcct, the invention features, in general, a shaving blade unit
with a housing
having a bottom surface and a top surface. At least one blade is mounted to
the housing. A solid
polymeric lubrication member composed of a water soluble polymer is positioned
in front of the
blades. The solid polymeric lubrication member has an upper skin contacting
surface. An
elastomeric member having a plurality of fins is positioned between the at
least one blade and the
solid polymeric lubrication member. The upper skin contacting surface of the
solid polymeric
lubrication member has an elongated portion in front of the fins and a pair of
lateral ends that
extend from the elongated portion toward the at least one blade. If, desired,
particular
embodiments may optionally include the fins positioned between the pair of
lateral ends of the
solid polymeric lubrication member. Particular embodiments may also optionally
include a pair
of clips securing the at least one blade to the housing such that the pair of
lateral ends of the solid
polymeric lubrication member are immediately adjacent to the clip. The clips
may be axially
aligned with the pair of lateral ends of the solid polymeric lubrication
member.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and
distinctly
claiming the subject matter that is regarded as the present invention, it is
believed that the
invention will be more fully understood from the following description taken
in conjunction with
the accompanying drawings.
Figure 1 is top view of one possible embodiment of a shaving blade unit.
Figure 2 is an assembly perspective view of the shaving blade unit of Figure
I.
Figure 3 is a cross section view of the shaving blade unit, taken generally
along the line 3-
3 of Figure 1.
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DETAILED DESCRIPTION OF THE INVENTION
Referring to Fig. 1, one possible embodiment of the present disclosure is
shown
illustrating a shaving blade unit 10. In certain embodiments, the shaving
blade unit 10 may be
detached and removed from a handle (not shown). The shaving blade unit 10 may
be fixedly or
pivotably mounted to the handle depending on the overall desired cost and
performance. The
shaving blade unit 10 may also include an interconnect member 16 to which the
shaving blade
unit 10 is pivotably mounted about a pivot axis. The shaving blade unit 10 may
include a
housing 18 that carries one more blades 20, a guard 22, a cap 24, and a solid
polymeric
lubrication member 25. The one or more blades 20 may be positioned between the
guard 22 and
the cap 24. Each blade 20 may have a blade edge 21 extending parallel to the
cap 24 and the
guard 22. The guard 22 and the cap 24 may define a shaving plane. In certain
embodiments, an
elastomeric member 30 may be mounted to the housing 18 between the guard 22
and the solid
polymeric lubrication member 25 (i.e., in front of the guard 22 and behind the
solid polymeric
lubrication member 25). The guard 22 may be segmented, as shown, or may be a
continuous bar.
The solid polymeric lubrication member 25 may be injection molded from a
combination
of one or more water-soluble polymers (c.g., polyethylene oxides generally
known as POLYOX
(available from Dow Chemical)) and a non water soluble polymer (e.g., high
impact
polystyrene). The delivery of lubrication in the form of an injection molded
lubricating element
has typically involved a three material molded frame in which the lubrication
element is molded
onto a substrate base (e.g., the Venus Embrace sold by the Gillette Company).
This design and
method involves maintaining geometry of the frame as multiple injection molded
materials cool
at different rates, which causes warping. A single molded lubrication bar
(i.e., a unitary member)
being assembled into a pre-molded housing provides numerous advantages. For
example, this
approach allows each element to be optimally controlled during injection
molding therefore
enabling more consistent geometry which is important for a close, comfortable
shave. Injection
molding of the solid polymeric lubrication member 25 also allows for a greater
variety of shapes
(e.g., compared to extruded lubrication bars) and different surface textures
to be added.
However, the solid polymeric lubrication member 25 must be strongly secured to
the housing 18
because swelling of the solid polymeric lubrication member 25 during shaving
may cause the
solid polymeric lubrication inember 25 to separate from the housing 18.
The shape of the solid polymeric lubrication member 25 may have a generally
low profile
to facilitate mounting to the housing 18, thus enabling the housing 18 to also
have a low profile.
The solid polymeric lubrication member 25 may have an upper skin contacting
surface 40 and an
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opposing bottom surface (not shown). The upper skin contacting surface 40 may
have a
generally U-shaped profile to provide improved glide and a more comfortable
feel against the
skin of the user (e.g., compared to an extruded lubrication strip). The upper
skin contacting
surface 40 may have an elongated portion 44 in front of the elastomeric member
30. The
5 elongated portion 44 may extend parallel to the at least one blade 20. A
pair of lateral ends 46,
48 may extend from the elongated portion 44 toward the at least one blade 20.
The pair of lateral
end 46,48 may extend transverse to the at least one blade 20 and/or the
elongated portion 44 of
the upper skin contacting surface 40. In certain embodiments, upper skin
contacting surface 40
may be smooth. However, other embodiments might include the use text, texture,
pattern, lines,
to icons, or channels to promote a particular aesthetic or functional
benefit, for example, skin
stretching of tactile feel on the skin.
The one or more blades 20 may be mounted within the housing 18 and secured
with one
or more clips 26. The clips 26 may be parallel to each other and may extend
into the housing to
secure the blades to the housing. Other assembly methods known to those
skilled in the art may
also be used to secure the one or more blades 20 to the housing 18 including,
but not limited to
wire wrapping, cold forming, hot staking, insert molding, and adhesives. The
combination of the
solid polymeric lubrication member 25 and the clips 26 may improve the glide
of the shaving
blade unit 10 against the skin during a shaving stroke. The lateral ends 46,
48 of the solid
polymeric lubrication member 25 may be positioned directly in front of (e.g.,
immediately
adjacent) the clips 26. Accordingly, glide may be enhanced because lubricants
released from the
solid polymeric lubrication member 25 may be deposited directly onto the
metallic clips 26
during a shaving stroke. The respective clips 26 may be spaced apart from the
lateral ends 46, 48
during assembly to allow the solid polymeric lubrication member 25 to absorb
water and swell
during use. As the solid polymeric lubrication member 25 swells, the lateral
ends may contact the
clips 26. The clips 26 may be axially aligned with the lateral ends to improve
the amount of
lubrication deposited onto the clips 26.
In certain embodiments, the elastomeric member 30 having a plurality of fins
32 between
the at least one blade and the solid polymeric lubrication member 25 to
stretch the skin for
proving a closer shave. The fins 32 may extend generally parallel to the at
least one blade 20
and/or the elongated portion 44 of the upper skin contacting surface 40 on the
solid polymeric
lubrication member 25. The elastomeric member 30 may be positioned between the
lateral ends
lateral end 46,48 to provide a sufficient amount of glide (e.g., lubrication)
and skin stretching.
For example, the shaving blade unit 10 may provide more glide toward the sides
of the housing
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18 and increased skin stretch in front of the blades 20 (i.e., toward the
middle of the housing 18)
while still providing lubrication in front of the blades 20. Accordingly, the
consumer may
experience increased comfort from the lubrication without sacrificing the
close shave achieved
by sufficient skin stretching in front of thc blades 20. In certain
embodiments, the elastomeric
member 30 may directly contact the solid polymeric lubrication member 25
(e.g., during
assembly or during a shaving stroke as the solid polymeric lubrication member
25 absorbs water
and swells). The close spacing of the elastomeric member 30 and the solid
polymeric lubrication
member 25 may facilitate more lubricants to be deposited onto the elastomeric
member 30. In
certain embodiments, an elongated gap 34 may be positioned between the guard
22 and the
to elastomeric member 30 (e.g., one of the fins 32).
In certain embodiments, the housing 18 may be molded from NorylTM (a blend of
polyphenylene oxide (PPO) and polystyrene developed by General Electric
Plastics, now SABIC
Innovative Plastics). The housing 18 may be molded from other semi-rigid
polymers having a
Shore A hardness of about 50, 60, or 70 to about 90, 110, or 120. The
solid polymeric
lubrication member 25 may be a separate molded component that is mounted to
the housing 18.
The solid polymeric lubrication member 25 may be molded from a lubricious
shaving aid
composite that has one or more water-leachable shaving aid materials to
provide increased
comfort during shaving. The shaving aid composite may include one or more skin
lubricating
water-soluble polymers such as, polyethylene oxide, polyvinyl pyrrolidone,
polyacrylamide,
hydroxypropyl cellulose, polyvinyl imidazoline, and
polyhydroxyethylmethacrylate. Other
water-soluble polymers may include the polyethylene oxides generally known as
POLYOX
(available from Dow Chemical) or ALKOX (available from Meisei Chemical Works,
Kyota,
Japan). These polyethylene oxides may have molecular weights of about 100,000
to 6 million,
for example, about 300,000 to 5 million. The polyethylene oxide may comprises
a blend of about
40 to 80% of polyethylene oxide having an average molecular weight of about 5
million (e.g.,
POLYOX COAGULANT) and about 60 to 20% of polyethylene oxide having an average
molecular weight of about 300,000 (e.g., POLYOX WSR-N-750). The polyethylene
oxide blend
may also contain up to about 10% by weight of a low molecular weight (i.e.,
MW<10,000)
polyethylene glycol such as PEG-100.
The shaving aid coiripositc may also optionally include an inclusion complex
of a skin-
soothing agcnt with a cylcodextrin, low molecular weight water-soluble release
enhancing agcnts
such as polyethylene glycol (e.g., 1-10% by weight), water-swellable release
enhancing agents
such as cross-linked polyacrylics (e.g., 2-7/0 by weight), colorants,
antioxidants, preservatives,
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microbicidal agents, beard softeners, astringents, depilatories, medicinal
agents, conditioning
agents, moisturizers, cooling agents, etc.
Referring to Fig. 2, a perspective assembly view of the shaving blade unit 10
is shown
illustrating the assembly of the solid polymeric lubrication member 25 to the
housing 18. The
solid polymeric lubrication member 25 may include a base 50 having a bottom
surface 52. The
bottom surface 52 of the solid polymeric lubrication member 25 (e.g., the base
50) may have at
least one protrusion 54, 56 having a length "Ll". In certain embodiments, the
solid polymeric
lubrication member 25 may have two spaced apart protrusions 54, 56. The length
of one or more
of the protrusions 54, 56 may be greater than the distance "dl" from the
respective protrusion 56
to a lateral edge 57 of the solid polymeric lubrication member 25 to improve
securement to the
housing 18. The protrusions 54, 56 may be spaced apart by a distance "d2" that
is less than the
length "Ll" of at least one of the protrusions. The protrusions 54, 56 may
each have an enlarged
distal end 58, 59 to secure the solid polymeric lubrication member 25 to the
housing 18. The
length of the enlarged distal ends 58, 59 may correspond to the overall length
Ll of the
corresponding protrusion 54, 56. The enlarged distal ends 58, 59 may each have
a width "wl"
(measured in a direction transverse to the blades) that is less than the
length Ll. For example, wl
may be about 0.75mm, 0.85mm, or 1.0mm to about 1.Imm, 1.2mm, or 1.3min. The
ditnensions
and spacing of the protrusions 54, 56 and the enlarged distal ends 58, 59 may
help prevent the
solid polymeric lubrication member 25 from separating from the housing 18 as
the solid
polymeric lubrication member 25 absorbs water and swells. For example, the
absorption of
water may cause the lateral end 57 to peel away from the housing.
The housing 18 may have a top surface 60 that defines a pocket 62 The top
surface 60 of
the housing 18 may also define least one aperture 64, 66 positioned within the
pocket 62 between
a front wall 68 of the housing 18 and the elastomeric meinber 30. For example,
the top surface
60 may define two spaced apart apertures 64, 66 that extend parallel to thc
fins 32 and/or the at
least one blade 20 and are positioned in front of the elastomeric member 30.
The apertures 64,
66 may extend from the top surface 60 to a bottom surface of the housing (not
shown). As will
be explained in greater detail below, the apertures 64, 66 may be dimensioned
to receive one of
the corresponding protrusions 54, 56. The apertures 64, 66 may each have a
length "L2" (i.e.,
measured parallel to the blade(s) 20) that is greater than its width "w2". For
exainple, L2 may be
about lOmm, Ilmm or 12mm to about 13mm, 14mm or 15mm. In certain etnbodiments,
w2 may
be about 0.75mm, 0.85mm, or 1.0mm to about 1.1mm, 1.2mm, or 1.3mm. The
apertures 64, 66
and/or the enlarged distal ends 58, 59 may have a length to width ratio that
is greater that 2:1 to
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improve the security of the solid polymeric lubrication member 25 to the
housing 18. In certain
embodiments, L2 may be greater than the length of the respective protrusions
54, 56 and/or the
respective enlarged distal ends 58, 59 by about 15% to about 40%. The
relationship between the
length of the apertures 64,66 and the length of the enlarged distal ends 58,
59 can impact
alignment during assembly and the amount of force required to deflect the
front wall 68 of the
housing, which may influence high speed assembly. For example, if the length
of the enlarged
distal ends 58, 59 are too similar to the length of the respective apertures
64, 66, the enlarged
distal ends 58, 59 may not align properly within the aperture 64,66 or the
assembly force may be
too great, thus damaging the enlarged distal ends 58, 59. The apertures 64, 66
may be spaced
apart by a distance "d3" to improve rigidity of the housing 18 and prevent the
solid polymeric
lubrication member 25 from distorting the housing 18 as the solid polymeric
lubrication member
25 swells. For example, a single elongated slot may cause the housing 18 to be
too flexible and
the solid polymeric lubrication member 25 may become disengage during use.
Now with additional reference to Fig. 3, the attachment of the solid polymeric
lubrication
member 25 to the housing 18 will be explained in greater detail. Fig. 3
illustrates a cross section
view of the shaving blade unit 10, taken generally along the line 3-3 of Fig.
1. The solid
polymeric lubrication member 25 may be attached to the housing 18 such that
the base 50 of the
solid polymeric lubrication member 25 is generally disposed within the pocket
62. The shape of
the pocket 62 may generally correspond to the shape of the solid polymeric
lubrication member
25. For example, a pair of sidewalls 70, 72 and the front wall 68 of the
housing 18 and the
elastomeric member 30 (e.g., a front wall 68 or the fins 32 of the elastomeric
member 30) may
surround the solid polymeric lubrication member 25. According, the housing 18
may help
contain the solid polymeric lubrication member 25 as the solid polymeric
lubrication member 25
absorbs water and swells during shaving.
The solid polymeric lubrication member 25 may be pressed into the pocket 62.
One or
more of the protrusions 54,56 may be pressed into one or more of the
corresponding apertures 64,
66 of the housing 18 with corresponding angles of the enlarged distal end(s)
58, 59 of the
protrusion(s) 54, 56 and the aperture(s) 64, 66 of the housing 18 facilitating
the front wall 68 of
the housing to deform. The front wall 68 of the housing 18 may also be
flexible to allow for
some expansion caused by the absorption of water and swelling of the solid
polymeric lubrication
member. The enlarge distal end(s) 58, 59 may pass through the corresponding
aperture 64,66
and engage a bottom surface 76 of the housing 18 to secure the solid polymeric
lubrication
member 25 in place such that the bottom surface 52 of the solid polymeric
lubrication member 25
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maintains contact with a flat seat surface 74 of the housing 18. The enlarged
distal ends 58, 59
are exposed to water because they engage the bottom surthee 76 of the housing
18. The solid
polymeric lubrication member 25 and the enlarged distal ends 58, 59 are molded
from a water
soluble polymer, as previously described. Accordingly, the enlarged distal
ends absorb more
water and swell to increase the force required to remove the solid polymeric
lubrication member
25 from the housing 18. As shown in Fig. 3, the solid polymeric lubrication
member 25 may
have a forward leading edge with a gradual slope. A gradual slop may be an
advantage
compared to typical straight lubrication bars because it may facilitate skin
flow over the solid
polymeric lubrication member 25 while simultaneously reducing skin drag.
The dimensions and values disclosed herein are not to be understood as being
strictly
limited to the exact numerical values recited. Instead, unless otherwise
specified, each such
dimension is intended to mean both the recited value and a functionally
equivalent range
surrounding that value. For example, a dimenSion disclosed as "40 mm" is
intended to mean
"about 40 mm".
The citation of any document is not an admission that it is prior art with
respect to the
present invention. To the extent that any meaning or definition of a term in
this document
conflicts with any meaning or definition of the samc term in a document cited
herein, the
meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated
and
described, it would be obvious to those skilled in the art that various other
changes and
modifications can be made without departing from the spirit and scope of the
invention. lt is
therefore intended to cover in the appended claims all such changes and
modifications that are
within the scope of this invention.
