Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
5302-04{~NA CA 02223161 1997-12-02
RAZOR HEADS HAVING INDEPENDENTLY FLEXIBLE BLADES
The present invention is directed to razor heads
comprising flexible blades, and more particularly, to razor
heads with at least two blades adapted to independently flex
in response to shaving forces.
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. In many instances, each of these
elements is typically 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 in response to forces encountered
during shaving.
It would be desirable to provide a razor head in
which at least two blades thereof are flexible, and more
particularly, are adapted to independently flex in response
to shaving forces to allow the blades to better conform to
the contours of the skin surface in order to achieve greater
comfort and closeness.
CA 02223161 1997-12-02
It would also be desirable to provide a razor head
in which a blade thereof is flexible and, more particularly,
the center portion of the blade has a greater stiffness
compared to the end portions thereof so as to provide a
s flatter curve along the length of the blade in response to
shaving forces.
SUMMARY OF THE INVENT!ON
Various embodiments of the present invention
provide razor heads which comprise a plurality of flexible
blades which are adapted to independently flex in response to
shaving forces.
Other embodiments of the present invention provide
razor heads having independent flexible blades in which at
least one blade is designed to have different stiff nesses
along its length, for example, to have greater stiffness in
the center compared to the end portions thereof so as to
produce a flatter curve in response to shaving forces.
Still other embodiments of the present invention
provide razor heads having independent flexible blades in
which the blade support is provided with a skin-engaging
shaving aid material.
These and other embodiments of the present
invention are described below with reference to the drawings.
~ CA 02223161 1997-12-02
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of one
embodiment of a razor head of the present invention.
FIG. 2 is an enlarged front elevational view of a
blade element shown in FIG. 1.
FIG. 3 is an enlarged side elevational view of a
blade element taken along line 3-3 of FIG. 2.
FIG. 4 is an enlarged cross-sectional view taken
along line 4-4 of FIG. 1 in which the razor head is
assembled.
DETAILED DESCRIPTION
The present invention provides razor heads with
blades adapted to flex during shaving in order to adapt to
the contours of a curved surface being shaved so as to
provide close and comfortable shaves. One preferred
embodiment of the present invention provides razor heads with
blades which are independently flexible within a generally
rigid blade support. An embodiment also provides blades
which have varying stiffs along their length. One embodiment
of the present invention, illustrated in FIG. 1, comprises a
razor head 10 generally comprising a blade support 20 and at
- CA 02223161 1997-12-02
least two, and preferably, three flexible blade elements 30
such as a leading blade element, a middle blade element, and
a trailing blade element.
s As used herein, the term "razor head" is meant to
include 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
formed as a single unit. Also, as used herein, the term
"flexible" is used to indicate a bending capability of a
blade along the blades longitudinal axis in response to
shaving forces. As such, the flexible blade elements of the
present invention differs from generally rigid blades which
may deflect vertically or angularly in response to shaving
IS forces.
As shown in FIGS. 1-3, blade elements 30 comprise a
generally elongate blade 40 attached to a generally
corrugated flexible member 50. The illustrated blade 40
comprises a cutting edge 42, a central opening (not shown)
and cutouts (not shown) at each end portion 44 and 46 through
which interlocking projections 52 of flexible member 50 can
extend for securing blade 40 to flexible member 50. Such a
configuration is ideally suited for assembly by plastic
insert molding. As shown best in FIG. 3, cutting edge 42 of
blade 40 extends outwardly from flexible member 50, i.e., the
portion of blade 40 containing cutting edge 42 is
cantilevered from flexible member 50.
CA 02223161 1997-12-02
As shown in FIG. 2, flexible member 50 preferably
comprises a generally sinusoidal configuration, and
particularly, a generally rectangular sine wave
configuration, in which portions thereof provide a generally
flat top surface for supporting blade 40. Flexible member 50
also comprises tabs 54 and 56 which extend outwardly beyond
the end portions 44 and 46 of blade 40. As explained in
greater detail below, tabs 54 and 56 are movably supported in
blade support 20 so that blade elements 30 can be
repetitively flexed therebetween in response to shaving
forces. When such shaving forces are removed, the inherent
resiliency of blade element 30 is preferably sufficient to
return the blade element to an original position.
From the present description it will be appreciated
by one skilled in the art that by varying height H, width W,
thickness T of a flexible member, as well as the spacing V
between vertical portions of a flexible member, the stiffness
can be increased or decreased. In addition, from the present
description those skilled in the art will appreciate that
other factors will also affect the stiffness of the flexible
member, e.g., the inherent stiffness of the type of material
used. It will also be appreciated that varying the number of
interlocking pro;ections which attach the flexible member to
the blade will also affect the stiffness of the resulting
blade element.
CA 02223161 1997-12-02
Preferably, the blade elements are designed to have
a varying stiffness along their length. For example, it is
presently believed to be preferable to provide a blade
element having a greater stiffness in the center portion
compared to the end portions to provide a flexible blade
having a flatter curve in the central portion. In
particular, since the guard bar is generally rigid it will
flatten the skin in front of the blade and a stiffer center
portion will correspond more closely to the configuration of
the skin, limiting the variation in blade protrusion (i.e.,
amount the blade edge extends from a tangent line connecting
a cap and a guard) and limiting the variation in the
effective shaving angle between the blade and the skin.
With reference again to FIG. 1, blade support 20
comprises a frame 60 and a base 70. The illustrated frame 60
comprises a cap 62, a guard 64, and sides 66. Desirably, cap
62, guard 64 and sides 66 are formed as a single unit, e.g.,
formed from an injected molded polymeric material such as
polyethylene, polyvinyl chloride or combinations thereof.
From the present description it will be appreciated that
instead of a guard being integrally formed with the frame,
the guard can be attached or integrally formed with the base.
To retain the blade elements in the blade support, the frame
and the base are suitably attached to each other, e.g., by
adhesives, thermal bonding or a snap-fit.
CA 02223161 1997-12-02
As illustrated in FIG. 4, blade elements 30 are
disposed, when assembled, in a vertically spaced relation, as
well as disposed in a horizontally spaced relation across the
width of the blade support. In particular, frame 60 and base
5 70 cooperate to provide a generally rigid support which
generally does not flex or bend as a result of shaving
forces. The present invention translates forces on the
blades into deflection while the cap and guard remain
stationary. Specifically, base 70 is provided at its ends
with steps 72, and sides 66 of frame 60 are provided with
corresponding slots 68 (best shown in FIG. 1) to movably hold
each blade element 30 therebetween. This illustrated blade
support arrangement permits inward movement of tabs 54 and 56
in response to shaving forces along the length of blade
element 30 without disengaging the tabs from the slots.
Although the blade elements are illustrated as separate, from
the present description it will be appreciated by those
skilled in the art that the blade elements can be attached at
their end portions, e.g., the flexible elements can be molded
as a unit with their end portions attached so that the blades
are disposed in spaced vertical relation and spaced
horizontal relationship across the width, and the molded unit
can be provided with a single tab on each end which is
retained in a blade support.
From the present description, it will also be
appreciated by those skilled in the art that the present
invention eliminates the need for a separate spacer element
CA 02223161 1997-12-02
installed between adjacent blades of unitary dynamic razor
systems, e.g., shaving systems where the cap and guard, as
well as the blades flex as one. In addition, the
independently flexible blade elements of the present
invention allow the blades to have a greater flexibility
without compromising structural integrity.
As shown in FIG. 1, blade support 20 preferably
comprises wash through slots for rinsing shaving debris from
the spaces between the blades. Specifically, frame 60
desirably has a rear wall 61 having openings 63, and base 70
desirably has openings 73 which, in conjunction with the
openings in flexible member 50, provide passageways for
rinsing shaving debris from the spaces between the blades.
Razor head 10 of the present invention is assembled
by inserting blade elements 30 sequentially in frame 60.
Specifically, the rear trailing blade element is inserted
first, the middle blade element is inserted next, and the
leading blade element inserted last. The base is then
attached to the frame to secure the blade elements therein.
The base is suitably attached to a separate razor for wet
shaving.
The blade elements being similarly configured
reduce the cost of the shaving system by reducing the number
of different elements of the razor head, and thus, the
tooling required and the cost and time required for assembly.
CA 02223161 1997-12-02
In particular, the similarly configured blade elements of the
present invention reduce the complexity for forming the razor
head in that individual blade elements can be readily
inserted in the desired slots of the blade support. Also, by
increasing the number of blade edges in contact with a skin
surface, shaving forces are distributed over a greater area
in order to provide a more comfortable shave.
Another preferred embodiment of the present
invention comprises a razor head, as described above, in
which shaving system 10 further comprises a skin-engaging
shaving aid material. Preferably, a shaving aid material 80
is attached to cap 62 of blade support 20.
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
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.
. CA 02223161 1997-12-02
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
s 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 blood coagulant for the suppression of
bleeding that occurs from nicks and cuts.
H. An astringent for constricting blood
vessels thereby stemming the flow of bodily fluids
such as lymph, which may exude from skin which has
been irritated during shaving.
Alternatively, the shaving aid may comprise one or more of
the shaving aids disclosed in U.S. Patent No. 5,056,221 to
CA 02223161 1997-12-02
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 include various
pigments,
i.e., titanium dioxide, fragrances, aloe vera, flavoring
agents, mineral oils, essential oils and other oils derived
10 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.
