U.S. patent number RE30,913 [Application Number 06/112,757] was granted by the patent office on 1982-04-27 for safety razor with flexible blade cartridge.
This patent grant is currently assigned to Warner-Lambert Company. Invention is credited to Cyril A. Cartwright, James S. Emmett, Arthur E. Michael, Anthony J. Peleckis, Ernest M. Symes.
United States Patent |
RE30,913 |
Cartwright , et al. |
April 27, 1982 |
Safety razor with flexible blade cartridge
Abstract
A razor blade assembly which is flexible in at least one bending
mode. A seat member of substantially planar shape has an integrally
formed guard located transversely along its forward margin. The
guard and seat members are formed of a flexible material. A
flexible blade having a sharpened edge along a transverse margin is
disposed on a surface of the seat member having its edge parallel
to and rearwardly located of the guard bar. A cap member of
flexible material has a planar surface in contact with the blade
and a front margin located rearwardly of the cutting edge. The
seat, blade and cap are yieldingly bonded together and freely
flexible about an axis parallel to the plane of the blade and
perpendicular to the cutting edge.
Inventors: |
Cartwright; Cyril A. (Monroe,
CT), Emmett; James S. (Ansonia, CT), Michael; Arthur
E. (Middletown, CT), Peleckis; Anthony J. (Fairfield,
CT), Symes; Ernest M. (Guilford, CT) |
Assignee: |
Warner-Lambert Company (Morris
Plains, NJ)
|
Family
ID: |
22345682 |
Appl.
No.: |
06/112,757 |
Filed: |
January 17, 1980 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
715272 |
Aug 18, 1976 |
04069580 |
Jan 24, 1978 |
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Current U.S.
Class: |
30/47; 30/32;
30/346.58; 30/50 |
Current CPC
Class: |
B26B
21/4012 (20130101) |
Current International
Class: |
B26B
21/40 (20060101); B26B 21/00 (20060101); B26B
021/14 () |
Field of
Search: |
;30/32,40.1,47,50,49,77-81,83,345,346.57,346.58,346.59 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Gary L.
Attorney, Agent or Firm: Strickler; R. S.
Claims
What is claimed is:
1. A razor assembly comprising a blade assembly including a seat
member and a blade disposed thereon, the seat and blade being
bonded together and flexible about an axis substantially parallel
to the plane of the blade and perpendicular to its cutting edge, a
razor handle for holding the blade assembly, and coupling means for
connecting the blade assembly to the razor handle and permitting
the blade assembly to flex .[.in both convex and concave
directions.]. .Iadd.selectively in the convex or concave mode
.Iaddend.in response to shaving forces.
2. The blade assembly of claim 1 comprising a seat member having a
surface of substantially planar form, a blade having a sharpened
cutting edge disposed on the surface, a cap member on the blade
having a forward margin located rearwardly of the cutting edge, and
a guard member located forwardly of the cutting edge, the seat,
blade, cap and guard member being yieldingly bonded together and
flexible about an axis parallel to the plane of the blade and
perpendicular to the cutting edge.
3. A razor assembly comprising:
a seat member having a substantially planar surface and a guard bar
member integrally formed transversely along its forward margin, the
guard and seat members formed of a flexible material;
a flexible blade member having a sharpened edge along a transverse
margin disposed on the planar surface with its edge parallel to and
rearwardly located of the guard bar member;
a cap member of flexible material having a substantially planar
surface in contact with the blade and a front margin located
rearwardly of the cutting edge, the seat, blade and cap members
being yieldingly bonded together to form a blade assembly flexible
about an axis substantially parallel to the plane of the blade and
perpendicular to the cutting edge;
a razor handle for holding the blade assembly; and
pivot means for connecting the blade assembly to the razor handle
and for .[.convex and concave.]. flexing of the blade assembly
.Iadd.selectively in the convex or concave mode .Iaddend.in
response to shaving forces.
4. The assembly of claim 3 wherein the pivot means includes linkage
means.
5. The assembly of claim 3 wherein the pivot means includes two
pins projecting outwardly of the coupling means coaxially aligned
and in registration with a first channel and a second channel in
the seat member, respectively, the first and second channels being
in a plane parallel to the plane of the blade and perpendicular to
the cutting edge.
6. The assembly of claim 5 wherein the seat member comprises a
series of rib members interconnected by webs, and arrayed
orthogonally to the front margin of the seat member.
7. The assembly of claim 6 wherein the guard bar member is a comb
guard bar, the teeth of which are formed by forwardly extending
portions of the rib members.
8. The assembly of claim 7 wherein the teeth of the comb guard bar
member have a pitch dimension greater than approximately 0.090 inch
and less than approximately 0.200 inch and the interconnecting web
has a thickness greater than approximately 0.010 and less than
approximately 0.030 inch.
9. The assembly of claim 8 wherein each tooth of the comb guard bar
assembly has a width approximately greater than 25% and less than
approximately 75% of the pitch dimension.
10. The assembly of claim 5 wherein the first and second channels
have a center-to-center spacing greater than 40%.
11. The assembly of claim 10 wherein the first and second channels
have center-to-center spacing less than 75% of the transverse
length of the seat member, and the first channel has a transverse
dimension greater than the transverse dimension of the pin in
registration therewith so as to allow the pin to move transversely
within the first channel during flexure of the assembly.
12. The assembly of claim 11 wherein the seat, guard bar and cap
members are molded from a flexible polymeric material selected from
the group consisting of polyvinyl chloride, polyethylene, ethylene
vinyl acetate, silicone, urethane and thermoplastic rubbers.
13. The assembly of claim 12 wherein the assembly is yieldingly
bonded with adhesives selected from the group consisting of
acrylics, rubbers, silicones, and synthetics.
14. The assembly of claim 13 comprising a second blade disposed
parallel to and rearwardly of the blade, and interposed between the
blade and the cap member.
15. The assembly of claim 14 wherein the second blade is yieldingly
bonded.
16. The assembly of claim 15 wherein the members are bonded by
adhesive strips interposed between each of the members, and the
assembly includes a spacer member interposed between the blade and
the second blade.
17. The assembly of claim 16 wherein the substantially planar
surface of the cap member is in contact with the adhesive strip
engaging the second blade, the blade seat has a transversely
extending rear margin perpendicular to the axes of the first and
second channels which extend therethrough, the coupling means has a
substantially planar surface from which pivot pins extend, which
surface abuts and is parallel to the rear margin.
18. The assembly of claim 17 wherein the pivot pins have expanded
heads on their distal ends, the first and second channels terminate
in a plenum formed in the blade seat into which plenum the expanded
heads of the pivot pins extend when the pivot pins are in
registration with the first and second channels.
19. The assembly of claim 18 wherein the seat member comprises a
series of rib members interconnected by webs, and arrayed
orthogonally to the front margin of the seat member, and the first
and second channels are contained in first and second ribs
respectively of increased transverse dimension.
20. The assembly of claim 19 wherein the plenum is extended to form
bifurcated members on both the first and second ribs, the
bifurcated members extending to form teeth of the comb guard.
21. The assembly of claim 20 wherein projections are included at
each end of the guard bar member to mask the blade edges.
22. The assembly of claim 3 having a shaving geometry as follows:
tangent angle between approximately 15.degree. and 40.degree.;
exposure between approximately -0.010 inch and +0.006 inch; span
between approximately 0.030 and 0.080 inch.
23. The assembly of claim 22 wherein the tangent angle is
approximately 20.degree. to 24.degree., the exposure is
approximately -0.004 to +0.002 inch, and the span is approximately
0.045 to 0.070 inch.
24. The assembly of claim 23 comprising a second blade disposed
parallel to and rearwardly of the blade and interposed between the
blade and the cap member, and wherein the shaving geometries of the
blade and the second blade are as follows: tangent angle between
approximately 15.degree. and 40.degree.; exposure between
approximately -0.010 inch and +0.006 inch; span between
approximately 0.030 and 0.080 inch.
25. The assembly of claim 24 wherein the blade and the second blade
have a tangent angle of approximately 20.degree. to 24.degree.,
exposure of approximately -0.010 to +0.006 inch, and span of
approximately 0.045 to 0.070 inch.
26. The assembly of claim 25 wherein the tangent angle of the
second blade is less than the tangent angle of the blade.
27. The assembly of claim 7 wherein the assembly is integrally
molded from a flexible material.
28. The assembly of claim 27 wherein the blade is movably attached
to the molded assembly.
29. The assembly of claim 28 comprising a second blade movably
attached to a second complementary slot in the assembly and
disposed parallel to and rearwardly of the blade, and interposed
between the blade and the cap member of the assembly.
30. The assembly of claim 29 wherein the blades are adhesively
bonded.
Description
BACKGROUND OF THE INVENTION
This invention is directed to a novel safety razor construction and
more particularly directed to a flexible razor blade assembly.
Since the introduction of the safety razor, the blade assembly has
consisted principally of three members, namely, a handle, a guard
bar and seat combination, and a cap. The function of the guard
bar/seat and cap is to properly locate and hold the blade in the
proper location for cutting hair in controlled contact with the
skin. Generally these elements have been manufactured as separate
components which, when removably attached or fixedly attached to
the handle, combine to maintain desired geometry in relationship of
these elements during the act of shaving.
Of more recent development is the bonded cartridge or razor blade
assembly in which the seat, cap and blade are permanently and
rigidly bonded together to achieve and maintain a desired shaving
geometry and fixed relationship of the parts. In this arrangement,
the cartridge is adapted to be coupled as a complete and unitary
assembly to the handle. This type of configuration is exemplified
and disclosed in U.S. Pat. No. 3,783,510, which employs a tandem or
twin blade assembly with a spacer therebetween permanently and
rigidly bonded to a cap and platform member, the platform member or
seat having an integral guard bar and coupling members for
attachment to the handle.
The advantage of the bonded cartridge is mainly one of convenience.
It achieves no more than prior art shaving systems previously
described, i.e., discrete components assembled to the razor handle,
but it does provide some ease of handling with a concomitant
increase in price.
There have been attempts to alter the operation and geometrical
relationships of the blade assembly to achieve increased shaving
comfort and efficiency. U.S. Pat. No. 1,383,783 describes a shaving
system having a number of parallel arrayed blades fixed to a
flexible support or platform, the purpose of the flexible support
being to provide or enable the razor to adapt itself to contours of
the face while being moved thereover. The platform of this prior
art device is flexible about an axis parallel to the plane of the
blades and to the edges thereof; hence such structure fails to
permit the blade itself to conform to facial or body contours.
Another attempt to fashion a blade assembly adaptable to user
requirements is described in U.S. Pat. No. 3,500,539. The device
described therein utilizes a transversely arrayed guard bar
connected to the blade platform by a yieldable web structure.
Dependent upon the applied shaving force, the orientation of the
guard with respect to the blade edge is altered resulting in
changing blade exposure, blade tangent angle, and shaving angle.
These terms are defined as follows: The blade exposure is the
normal distance the blade edge extends above or below a plane
tangent to the cap and guard bar; the blade tangent angle is the
angle formed between a plane tangent to the blade edge and the
guard bar and a second plane bisecting the blade edge; the shaving
angle is the angle formed between the plane bisecting the blade
edge and the plane tangent to the cap and guard bar. Theoretically,
this type of arrangement might permit a shaver to select desired
geometry by the application of a controlled force. However, in
practical application, the achieving of the desired geometry in
this fashion has proven difficult. It is further pointed out that
the structure of this patent fails to provide for adaptability to
the contours of the shaver's face or body.
Applicants have realized the desirability of a shaving system which
would maintain uniform, consistent geometry when in use but which
would also allow the blade to substantially conform to the contours
of the skin surface in order to achieve greater comfort, safety and
efficiency. Such a system would allow selection of optimum shaving
geometry and, if given sufficient flexibility, would permit the
maintenance of optimum geometry while the system was conforming to
varying contours. Flexing of the assembly may be derived through
mechanical or structural changes of the blade assembly or through
the utilization of materials which allow the cap and seat to
yieldingly follow changing contours. In using a device of this
nature, the cutting edge is allowed to stay in contact with a
maximum amount of skin surface despite undulations therein, which a
non-flexible system might only achieve when shaving a surface
parallel to the blade edge. Obviously, the latter surface is
unavailable on the human body.
The intent of this invention is to define and provide a system
which maintains uniform and consistent shaving geometry while
substantially conforming to the contours of the skin surface.
Another object of the invention is to provide a flexible razor
blade assembly wherein the cutting edge is maintained in optimum
contact with the skin surface. Yet another object of the invention
is to provide a unitary bonded flexible shaving cartridge having at
least one razor blade therein. Yet another object of the present
invention is to provide a flexible cartridge in which the
components thereof are yieldingly bonded together.
SUMMARY OF THE INVENTION
The foregoing disadvantages of prior art systems and the objects of
the invention are satisfied and achieved by the present invention
which contemplates a blade assembly in which a seat member and a
blade disposed thereon are flexible about an axis parallel to the
plane of the blade and perpendicular to its cutting edge.
Another aspect of the present invention contemplates a seat member
having a substantially planar surface and an integral platform
formed transversely along a forward margin, the guard and seat
members being formed of a flexible material. A flexible blade
having a sharpened edge along a transverse margin is disposed on
the seat member in contact with the planar surface with its edge
parallel to and rearwardly located of the guard bar. A cap member
of flexible material has a planar surface in contact with the blade
surface and a front margin located rearwardly of the cutting edge,
the seat member, guard member, blade, and cap being yieldingly
bonded together and flexible about an axis parallel to the plane
and perpendicular to the cutting edge. In another aspect of the
invention, cap and seat members are bonded together with a blade
interposed therebetween, the assembly being flexible about an axis
parallel to the plane of the blade and perpendicular to the cutting
edge and wherein the shaving angle and blade tangent angle and
exposure remain substantially constant during flexure of the
assembly.
Another aspect of the invention contemplates seat, guard bar and
cap members molded from a flexible polymer or other flexible
material and in which the seat member has a plurality of ribs in
parallel array perpendicular to its forward margin, the ribs being
interconnected by flexible webbing, thereby permitting flexure of
the assembly about an axis parallel to the plane of the blade and
perpendicular to the cutting edge.
The objects and features of the present invention will be apparent
upon consideration of the detail and specification hereafter set
forth taken in conjunction with the drawings. The drawings are
intended to be exemplary of the invention and standard symbols are
used with consistent numbering throughout the different views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded fragmentary view of a twin blade cartridge
and razor handle made in conformity with the present invention;
FIG. 2 is a perspective view of the blade seat of FIG. 1;
FIG. 3 is an exploded perspective view of a single blade cartridge
made in accordance with the present invention;
FIG. 4 is a schematic cross-sectional view of a blade assembly
showing blade angle, tangent angle, and exposure;
FIG. 5 is a schematic perspective view showing the cartridge in
concave flexure;
FIG. 6 is a schematic perspective view showing the cartridge in
convex flexure; and
FIG. 7 is a perspective view of another embodiment of the present
invention .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a razor blade assembly 10 made
in conformance with the present invention. A flexible seat member
11 having an integral guard bar 23 is assembled to an adhesive
strip 12, a first blade 13, a second adhesive strip 14, a spacer
member 15, a third adhesive strip 16, a second blade 17, a fourth
adhesive strip 18, and finally a cap member 19. When brought
together under suitable compressive forces, the assembly comprises
a bonded twin blade cartridge flexible about an axis parallel to
the plane of the blades and perpendicular to their edges. A head
member 20 of a shaving handle (not shown) connects to seat 11 by
means of linkage pins 21. When head 20 is coupled to seat 11, face
32 engages face 36.
Referring also to FIG. 2, seat 11 includes an upper planar surface
8, a rear margin or face 32 and side margins 9. Comb guard bar
member 23 is transversely arrayed along the front margin of seat 11
having raised portions or members 22 located at each end thereof to
protect the user from coming in contact with blade corners. Seat 11
is formed by a series of parallel arrayed ribs 33 running
transversely along its entire length and arranged perpendicular to
its front margin. End ribs 32a are of greater cross-section than
ribs 33 to lend structural integrity and cross-axis stiffness to
the assembly. Ribs 32a found at either end of seat 11 are
integrally formed with and terminate in end members 22. Also formed
of greater cross-section than ribs 33 are ribs 28 and 29 containing
channels 24 and 25 into which pins 21 of head 20 are inserted.
Channel 24 is circular in cross-section extending from margin 32 to
a point rearward of the front margin. Channel 24 opens into an
enlarged plenum 26 from which point on rib 28 is bifurcated forming
two ribs having substantially the same cross-sectional dimension as
ribs 33. When one of linkage pins 21 is inserted through channel
24, its expanded head is received in plenum 26, thereby allowing
free rotation of pin 21 in channel 24, the dimensions of which are
controlled accordingly. The enlarged head of pin 21 restricts
extraction from channel 24. Channel 25 opening into plenum 27 is
substantially similar to channel 24 and plenum 26 except for its
elliptical cross-sectional geometry. The ellipsoidal shape is
selected so as to permit translational movement of pin 21 in
channel 25 during flexure of seat 11. It can be appreciated that if
seat 11 where flexed to conform to some given geometry the
circumferential length of the arc segment located between the axes
of channels 24 and 25 would need increase, such increase being
compensated for by translational movement of pin 21 in channel
25.
A preferred construction of seat 11 finds a web thickness of
approximately 0.014 to 0.016 inch as providing optimal flexibility
although this dimension may vary from approximately 0.010 to 0.030
inch without seriously diminishing performance. It has been further
found that the tooth width of comb guard bar 23 is preferably
approximately 50% of the pitch increment, i.e., half the dimension
from one face of the tooth to the same face of the next tooth,
although again this dimension may be varied from about 25% to 75%
of the pitch increment without seriously affecting performance. The
pitch increment itself is preferably approximately 0.124 to 0.126
inch, but may be varied between approximately 0.090 and 0.200 inch
in practice of the invention. To achieve desired bending or flexure
of cartridge 10, pivot linkage pins 21 and channels 24 and 25 may
be spaced apart a distance equaling approximately 50% of the
transverse length of seat 11. In a typical cartridge 10 design,
this distance may vary and, for example, in a cartridge having a
transverse length of 1.6 inches the center-to-center spacing of
channels 24, 25 may be approximately 0.976 inch. A decrease in
pivot pins 21 center-to-center spacing generally favors or
decreases the forces necessary in producing convex deflection while
an increase in center-to-center spacing produces the converse. In
some applications it has been found advantageous to place the pins
in end ribs 32a to provide minimum concave flexure force. With
regard to deflection forces, lands 34 and 35 are placed about the
entrance apertures of channels 24 and 25, respectively. The lands
minimize the area contact between margin 32 and face 36 of holder
20. It should also be noted that cartridge 10 bending may be
achieved through a number of pivot linkage designs, e.g., rotatable
cams, compliant materials, etc.
Seat 11 is preferably injection molded of a flexible plastic
material such as polyvinyl chloride, polyethylene, ethylene vinyl
acetate, silicone, urethane and thermoplastic rubbers. A number of
products presently on the market, for example, Firestone FPC-1376,
Uniroyal TPR-1600E, B. F. Goodrich 83794 and Dupont Alathon 3175,
represent suitable molding materials containing the foregoing
generic polymers. In a functional sense, a suitable material may be
considered to be a polymer having required flexibility and
stiffness which is capable of being adapted to high production
molding techniques. The flexibility of the material in cooperation
with the structural design provides the necessary compliance to
satisfy the demands of the present invention.
Adhesive strips 12, 14, 16 and 18 act to bond the components of the
cartridge together. Suitable adhesives are acrylics, rubbers,
silicones and various other synthetics. Examples of adhesive
products now available which have been found suitable are Minnesota
Mining & Manufacturing 415,463 Acrylic, NPE 901 Synthetic
Rubber, and Dennison Silicone Rubber. Use of adhesives permits
relative motion between each of the assembly elements during
flexure of cartridge 10, thus reducing bending forces and
permitting greater conformity to skin contours. The use of such a
yieldingly bonded laminar structure allows bending of cartridge 10
with a minimum geometrical distortion while permitting the
component parts to return to their normal positioning upon the
release of applied force. A typical cartridge assembly requires a
9.1 gram shaving force to cause a 0.050 inch center deflection with
respect to the normal plane of the top surface of cap 19. The
adhesive strips are preferably about 0.002 inch thick, but may be
substantially varied in such dimensions without deleterious effect
upon the performance of the product.
After disposition of tape strip 12 on top surface 8 of seat 11,
blade 13 having a sharpened edge along its front margin is aligned
rearwardly of the front margin of seat 11 and yieldingly held in
that position by strip 12. Perforations 5 are longitudinally
arrayed along its transverse length, which perforations act to
increase flexibility of blade 13 as well as being used during the
edge grinding process. Changes in perforation dimensions and
locations may be used to tailor blade 13 flexibility.
Adhesive strip 14 is then placed along the top surface of blade 13
in alignment with its rear margin. In the twin blade design shown
in FIG. 1, a spacer member 15, again aligned with the rear margin
of blade 13, is then bonded to strip 14. Spacer member 15 separates
the blades to provide desirable twin blade shaving geometry. Spacer
15 is normally approximately 0.015 to 0.020 inch thick and is
fabricated from a flexible material. Over spacer 15 is placed
adhesive strip 16, blade 17 and adhesive strip 18, all aligned
along their rear margins. Blade 17, as is the case in blade 13, has
perforations 26 along its transverse length to increase flexibility
thereof. The width of blade 17 is less than that of blade 13 so
that its cutting edge lies rearwardly of the cutting edge of blade
13 and produces the aforementioned desired twin blade shaving
geometry. Blades 13 and 17 are preferably approximately 0.0015 inch
thick made of ferritic stainless steel commonly available for blade
fabrication. It has been found that thicknesses ranging between
0.001 and 0.010 inch may be utilized but do not realize the same
optimal results.
The last element of assembly 10 is cap 19, which is yieldingly held
to cap blade 17 by adhesive strip 18 to prevent lifting of cap
leading edge 29. Flange members 30 of end walls 31 of cap 19 act to
cover the ends of the assembly. In viewing this completed assembly,
it becomes obvious applicants have produced a twin blade cartridge
yieldingly bonded together being flexible about an axis parallel to
the planes of the blades 13 and 17 and perpendicular to their
cutting edges.
A single blade construction conforming to the same functional
requirements is shown in FIG. 3. Single blade cartridge 40
comprises seat member 11 having integral guard bar 23 and end
projections 22 thereon. Adhesive strip 12 is disposed upon planar
surface 8 after which blade 13, adhesive strip 14 and cap 19 are in
sequence bonded thereto. The single blade cartridge 40 displays the
same flexure or bending characteristics as cartridge 10 and
produces a blade assembly capable of conforming to body contours
while retaining substantially constant shaving geometry. Referring
to FIG. 4, there is shown a schematic representation of single
blade shaving geometry utilized in the construction of cartridge
40. The span S referring to the distance measured between the tip
of blade 13 and a tangent point on comb guard 23 may be selected
between approximately 0.030 and 0.080 inch; tangent angle Alpha may
be selected between approximately 15.degree. and 40.degree.; and
exposure E may be selected in a range between -0.010 and +0.006
inch.
This same geometry may also be reflected in the twin blade
cartridge 10 design of FIG. 1 by applying the definitions to
different reference elements. To explain--the geometry of first
blade 13 falls within the same range as blade 13 of cartridge 40 if
second blade 17 is considered the equivalent part to cap flange 29,
i.e., the shaving angle plane is defined as a plane tangent to the
edge of blade 17 and guard bar 23 rather than tangent to cap flange
29 and guard bar 23. Similarly, the same construction can be
applied to second blade 17 in arriving at its shaving geometry by
substituting the edge of blade 13 for the tangent line of guard 23.
In a preferable embodiment based upon the foregoing premise, the
geometry of blades 13 and 17 are selected to be substantially the
same, namely, a span S of between 0.030 and 0.080 inch, a tangent
angle Alpha of between 15.degree. and 40.degree., and an exposure E
between -0.010 and +0.006 inch but with the second blade tangent
angle selected less than the first blade tangent angle. As the
thicknesses of blades 13 and/or 17 are altered, the arrangement and
dimensioning of the other elements of the cartridge must be altered
to achieve the same or a different desired shaving geometry. It is
these geometrical relationships that are maintained relatively
constant while the cartridge of the present invention is being
flexed through a range of different bending radii, both concave and
convex. The preferred embodiments of both the twin and single blade
cartridges have a tangent angle of approximately 20.degree. to
24.degree., an exposure of approximately -0.004 to +0.002 inch, and
a span of approximately 0.045 to 0.070 inch.
Reference to FIGS. 5 and 6 demonstrates in a schematic sense the
conformity of a bonded cartridge made in accordance with the
present invention. In FIG. 5, cartridge 50, shown as an idealized
flat rectangular prism, is conforming to a concavity in the shaving
surface with cartridge 50 being moved toward the observer.
Cartridge 50 assumes a complementary convex geometry with its
center portion deflecting from a plane containing pivot points 51
and 52 with the entire surface assuming a given radius of curvature
about axis 53. In FIG. 6, the same cartridge 50 is shown assuming a
concave geometry about axis of curvature 54 conforming to a
convexity in the shaving surface. As can be seen, the center of
cartridge 50 deflects below the plane containing pivot pins 51 and
52 while the ends of cartridge 50 deflect above the same plane. It
should be noted that the portions of the cartridge extending beyond
pivot points 51 and 52 may assume a totally different radius of
curvature from that occurring between the same pivot points.
Moreover, in conforming to undulations of the shaving surface, a
plurality of different radii of curvature may be achieved.
FIG. 7 shows an alternate embodiment of applicants' novel concept.
Here the entire blade assembly, absent the razor blades, of course,
is molded as a single integral piece, i.e., seat 61, guard bar 62
and cap 63 are integrally formed of a flexible polymeric material.
The construction consists of a series of ribbed structures joined
by thin flexible webs 67. Slots 65 and 66 are formed one below the
other respectively in each rib section of cartridge 60 and the
second and first blades are disposed in such slots. The blades may
be movably pinned or adhesively bonded to the slots to achieve
flexibility and may be arranged to conform to the shaving geometry
heretofore set forth. The same alternative configuration may be
utilized in a single blade design by the elimination of one of the
blade slots and a commensurate decrease in the vertical dimension
of the cartridge.
Applicants have produced a flexible shaving assembly capable of
conforming to the varying contours of the shaving surface with
minimal variations in shaving geometry. The novel cartridge
achieves a dynamic flexibility through a range of different
positions and forces applied by the user during the act of shaving.
It enables the cutting edge to contact an increased skin surface,
thereby producing enhanced shaving efficiency without degradation
in performance or comfort. The applicants' invention may be applied
to a wide range of varying cartridge designs, for example, the
guard bar may be incorporated directly on the blade edge by the
encompassing of such edge by a wire spirally wound about the blade
or the placement of projections along the blade edge; these
variations, as well as other modifications which may become evident
to one of ordinary skill in the art, are considered to be within
the scope and ambit of applicants' invention. The foregoing
description and drawings are intended to be illustrative of
applicants' invention and not in any way delimiting of its
scope.
* * * * *