Note: Descriptions are shown in the official language in which they were submitted.
CA 02373204 2002-02-25
PC1144i;ARDT
_1_
SHAVING SYSTEMS WHICH ACTIVELY FLEX A BLADE
The present invention is directed to wet shaving systems, and more
particularly, to wet shaving systems having means for linking a blade to a
support so
that the blade is actively flexed in response to shaving forces to
redistribute shaving
forces along a cutting edge of the blade.
BACKGROUND OF THE INVENTION
Shaving systems such as safety razors have found widespread use
for providing close and comfortable shaves. Safety razors typically include
one or
two blades disposed between a guard and a cap. Traditionally, each of these
elements was rigidly fixed relative to one another and disposed in skin-
engaging
contact during shaving. In recent years, dynamic shaving systems have been
introduced which permit one or more of the skin-engaging elements of the
shaving
system to move or flex in response to forces encountered during shaving. Such
systems are generally designed to conform to the shape of the surtace being
shaved.
Since forces directed on one element of some dynamic systems could move other
skin-engaging elements or change the manner in which other skin-engaging
elements contact the skin, uneven shaving could occur at different blades.
It would, therefore, be desirable to provide shaving systems which
actively flex at least one blade in response to shaving forces to redistribute
shaving
forces along a cutting edge of the blade in order to achieve greater
uniformity of
shaving forces, comfort, closeness, and to extend the life of the blade(s).
CA 02373204 2002-02-25
-2-
SUMMARY OF THE INVENTION
Various embodiments of the present invention provide wet shaving
systems which comprise a blade comprising a cutting edge, a support, and at
least
one attachment mechanism for connecting the blade to the support. The
attachment
mechanism is operable to actively flex the blade in response to shaving forces
to
redistribute cutting forces along a cutting edge of the blade.
Other embodiments of the present invention provide wet shaving
systems comprising a blade having a cutting edge, a support, and an attaching
mechanism for linking the blade to the support which is operable to actively
flex the
blade in response to shaving forces to conform the blade to the contours of a
skin
surface and a connecting mechanism for connecting the attaching r»chanism to
the
support so that the blade is self-orientating to the skin surface independent
from the
angle at which the razor is held.
These and other embodiments of the present invention are described
below with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of a wet shaving
system according to the present invention.
FIG. 2 is an enlarged elevational end view of the wet shaving system
shown in FIG. 1.
FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1.
CA 02373204 2002-02-25
-3-
FIG. 4 is a diagrammatic view corresponding to FIG. 3 in which the
blade illustrates a concave flex.
FIG. 5 is a diagrammatic view corresponding to FIG. 3 in which the
blade illustrates a convex flex.
FIG. 6 is a diagrammatic cross-sectional view of an alternative
embodiment of a wet shaving system according to the present invention.
FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6.
FIG. 8 is a diagrammatic cross-sectional view corresponding to FIG. 6
in which the blade illustrates a compound flex.
DETAILED DESCRIPTION
The present invention is directed to wet shaving systems comprising
at least one blade which is actively flexed during shaving to conform to the
contours
of a surface being shaved to provide close and comfortable shaves.
One illustrated embodiment of the present invention is shown in FIGS.
1 and 2, and comprises a razor head 10 comprising a flexible blade 20, a razor
30,
and a linkage 40 for linking blade 20 to razor 30. Linkage 40 is operable to
actively
flex blade 20 in response to shaving forces to redistribute shaving forces
across a
cutting edge 22 of blade 20 (FIG. 1 ).
CA 02373204 2002-02-25
As used herein, the term "razor head" is meant to indude cartridges
adapted to be connected to a separate razor as well as the operative cutting
portion
of a disposable razor wherein the handle and cutting portion are fortr~d as a
single
unit. Also, as used herein, the term "actively flex" is used to indicate
movement of
one portion of the blade in one direction in response to a shaving force
directed in the
opposite direction on a diff~rent portion of the same blade. As such, the
movement
of the blade of the present invention differs from that of generally rigid
blades whidi
may deflect vertically or angularly in response to shaving forces, and from
that of
flexible blades which exhibit simple downward flexing about their end
portions.
As shown in FIGS. 1 and 3, flexible blade 20 is attachable to a blade
housing 50 which comprises a seat 52, a flexible guard 54, a flexible cap 56,
and
sidewalls 58. The illustrated razor 30 which forms a rigs support comprises
iwo
upwardly extending supports 32 which attach to linkage 40 as explained in
greater
detail below.
As shown in FIG. 3, the illustrated linkage 40 extends befit and
attaches blade housing 50 to razor 30. In this embodiment, linkage 40
comprises a
plurality of linking members which, in response to shaving forces, actively
flex blade
housing 50 and blade 20. This active flexing redistributes shaving forces
between
the skin surface and blade housing 50 and blade 20, and in doing so,
redistributes
cutting forces along cutting edge 22 of blade 20. Desirably, linkage 40
conforms
blade 20 to a skin surface to evenly distribute cutting forces along cutting
eke 22 of
blade 20 thereby optimizing the life of blade 20.
More particularly, shaving forces directed along a portion of blade 20
cause adjacent portions of blade 20 to move upwardly to engage adjacent
portions of
CA 02373204 2002-02-25
-5-
a skin surface being shaved. In this illustrated embodiment, linkage 40
comprises a
first vertically extending link 42, a second vertically extending centrally
disposed link
44, and a third vertically extending link 46. Upper end portions of links 42,
44, and 46
attach to seat 52 of blade housing 50. Attached to and extending between the
lower
end portions of links 42, 44, and 46 is a cross-link 48. Central portions of
cross-link
48, i.e., between links 42 and 44, and 44 and 46, are supported by supports 32
of
razor 30. Cross-link 48 of this illustrated embodiment is formed of a single
flexible
material, however, from the present description those skilled in the art will
appreciate
that the cross-link can also be formed a plurality of relatively pivotal
segments. It will
also be appreciated that links 44, 46, and 48, and cross-links 48 can be
molded as a
unit, or fastened, e.g., by pivotal attachments or attached as othervvise
known in the
art.
As shown in FIGS. 4 and 5, blade housing 50 is linked to razor 30 via
linkage 40, which defines two overlapping side-by-side four-bar linkages
providing a
three-point attachment to blade housing 50 and a two-point attachment to razor
30.
When blade housing 50 and blade 20 are pressed against a curved surtace such
as
a chin, or a shin bone area, blade housing 50 and blade 20 are made to
actively flex
to the curvature of the contacted surtace to redistribute the shaving forces
thereon.
Specifically, cross-links 48 are pivoted about respective supports 32 in the
directions
of the curved double-headed arrows illustrated in FIGS. 4 and 5. For example,
as
illustrated in FIG. 4, when blade 20 and blade housing 50 is pressed against a
chin, a
localized shaving force represented by downwardly directed arrow A will move
link
44 downward and in doing so, links 42 and 46 will move upwardly to engage
adjacent
skin surfaces of the chin along the end portions of blade 20. If the forces on
the end
portions of the blade housing 50 and blade 20 exceed those on a central
portion,
CA 02373204 2002-02-25
-6-
such as when shaving under arms as illustrated in FIG. 5, in which the shaving
forces
are represented by downwardly directed arrows B, the central portion will move
upwardly to engage the skin surface.
From the present description, it will be appreciated by those skilled in
the art that by positioning links 44 and 46 at the end portions of blade
housing 50,
blade housing 50 and blade 20 will be actively flexed across their entire
lengths. As
illustrated, supports 32 provide sufficient height so that cross-links) 48
does not
contact razor 30 thereby preventing the blade from actively flexing. It may be
desirable to limit the permissible extent of active flexing by providing stops
(not
shown) which limit the movement of one or more links, e.g., links 48, and
thereby
restrict the degree of blade flexing to a predetermined range.
When such shaving forces are removed, the inherent resiliency of
blade 20, blade housing 50, and linkage 40 is preferably sufficient to return
blade 20,
blade housing 50, and linkage 40 to an original position. In addition, from
the present
description it will be appreciated by those skilled in the art that the blade,
the blade
housing and the linkage can be designed to provide a predetermined stiffness
along
the length of blade.
It will also be appreciated that the attachment of linkage 40 to
supports 32 of razor 30 can be configured to allow blade 20 to be self-
orientating to
the skin surface, i.e., blade housing 50 can be pivotally attached to the
razor.
An alternative embodiment of the present invention, illustrated in
FIGS. 6-8, provides a razor head 110 which comprises two separate linkage
CA 02373204 2002-02-25
-7-
arrangements such that the system will conform to complex surtace shapes as
shown
in FIG. 8.
In this illustrated embodiment, linkage 140 extends between and
attaches a blade 120 via a blade housing 150 to a razor 130. Linkage 140
comprises
a plurality of links which actively flex blade 120 and blade housing 150 in
response to
shaving forces to distribute shaving forces exerted on the blade and blade
housing
150, and in doing so, redistribute cutting forces along a cutting edge of
blade 120. In
this illustrated embodiment, linkage 140 comprises a plurality of links which
define
two separate four-bar linkages which are attached at an upper end to blade
housing
150, e.g., vertically extending links 142 and cross-links 148: Each four-bar
linkage is
attached at a central portion of cross-link 148 to the top of an upwardly
connecting
link 145, the bottoms of which are attached to opposite leaf springs 147 which
are
cantilevered from a support 132.
In this illustrated embodiment, leaf springs 147 maintain blade housing
150 in a position normal to the handle when no load is applied. However, leaf
springs
147 allow blade 120 and blade housing 150 to flex to the angles of the shaved
surface to advantageously maintain a generally constant pressure across blade
120
for shaving surfaces with complex shapes.
Blade housing 150 can also be self-orienting to a skin surface
independent of the angle of razor 130, i.e., blade housing 150 is adjustable
in the
directions of the double-headed arrow shown in FIG. 7. For example, this can
be
accomplished by internal or external pivot attachments known in the art or by
a
rocking-type pivot structure 170 as shown in FIG. 7. This illustrated
configuration can
CA 02373204 2002-02-25
.8.
be arranged to place the pivot point in a location that would optimize the
pivot location
to cause the blades) to stay on a curved shaving surface. In addition, the
pivot point
could be positioned to eliminate any rotational torque due to shaving forces
so that
the pivot action only reacts to the surface shape. Advantageously, this
configura~on
optimizes the position of the blade against a shaved surface to provide close
and
comfortable shaves.
From the present description it will be appreciated by those skilled in
the art that the illustrated razors and linkages of the present invention can
be made of
individual components that are subsequently assembled or integrally formed as
a unit
by an insert molding process. The upper portion of the linkage can be
releasably
attachable to the blade housing. It will also be appredated that the razor
head can
comprise one or more blades, and the blade and blade housing can comprise wire
or
foil wrapped blades.
Another preferred embodiment of the present invention comprises a
wet shaving system as described above, in which the blade housing further
comprises a skin-engaging shaving aid material. For example, as shown in FIG.
1,
razor head 10 comprises a shaving aid material 60 attached to cap 56 of blade
housing 50.
A number of different materials have been suggested for use as
shaving aids. The term "shaving aid," as used herein, refers equally either to
the
active ingredient combined within a delivery system, such as a water-insoluble
micro-
porous matrix structure or to the active ingredient alone. Previously
suggested active
ingredients include those disclosed in U.S. Patent No. 4,170,821 to Booth,
which is
CA 02373204 2002-02-25
hereby incorporated by reference. A shaving aid may comprise one or various
combinations of the following:
A. A lubricating agent for reducing the frictional forces
between the razor and the skin, e.g., a micro-encapsulated silicone oil.
B. An agent which reduces the drag between the razor
parts and the shaver's face, e.g., a polyethylene oxide in the range of
molecular weights between 100,000 and 6,000,000; a non-ionic
polyacrylamide; and/or a natural polysaccharide derived from plant
materials such as "guar gum."
C. An agent which modifies the chemical structure of the
hair to allow the razor blade to pass through the whiskers very easily,
e.g., a depilatory agent is one example.
D. A cleaning agent which allows the whisker and skin
debris to be washed more easily from the razor parts during shaving,
e.g., a silicon polyethylene oxide block copolymer and detergent such
as sodium lauryl sulphate.
E. A medicinal agent for killing bacteria, or repairing skin
damage and abrasions.
F. A cosmetic agent for softening, smoothing, conditioning
or improving the skin.
G. A bkxxf coagulant for the suppression of bleeding that
ocarrs from nicks and cuts.
H. An astringent for constricting blood vessels thereby
stemming the flaw of bodily fluids such as lymph, which may exude
from skin which has been irritated during shaving.
CA 02373204 2002-02-25
-10-
Alternatively, the shaving aid may comprise one or more of the shaving aids
disclosed in U.S. Patent No. 5,056,221 to Thoene, U.S. Patent No. 4,044,120 to
Rowsell et al., U.S. Patent No. 5,095,619 to Davis et al., or Japanese Patent
Application No. Hei 7 [1995] - 24156 to Miyazaki, et al. which are also hereby
incorporated by reference.
Other active ingredients may inGude various pigments,
e.g., titanium dioxide, fragrances, aloe vera, flavoring agents, mineral oils,
essential
oils and other oils derived from plants. In addition to one or more active
ingredients;
the shaving aids of the present invention may also comprise other compounds or
blends of compounds such as water-insoluble polymers such as polystyrene and
polypropylene.
