Enhanced cutting system for electric dry shavers

By providing an apertured foil for dry shavers having a natural radius of curvature which is defined by an elongated axis that is parallel to the longitudinal axis of the cutting blade assembly associated therewith, a substantially improved cutting system is attained. By employing the apertured foil of this invention, the apertured foil naturally wraps tightly about the cutting edges of the cutting blades and remains in close, following contacting interengagement therewith during use. In this way, close contacting interengagement of the apertured foil with the cutting edges of the cutting blades is maintained throughout the shaving use and substantially enhanced cutting results and comfort are realized.

TECHNICAL FIELD 
This invention relates to electric dry shavers and more particularly to 
improved apertured foils for substantially improving the comfort and 
cutting efficiency of electric dry shavers. 
BACKGROUND ART 
Over the last several years, both men and women have been increasingly 
drawn to the advantages provided by electric dry shavers. In general, the 
consuming public has found that the use of razors or other systems is 
extremely inconvenient for removing or shaving short hair or stubble, as 
commonly found in mens' beards and womens' legs. In addition, with the 
ever increasing time constraints and commitments individuals typically 
encounter, a fast and effective shaving system is most desirable. 
The discomfort, as well as the time consumed in using shaving cream, soaps 
or gels in order to provide a medium for which a razor can be used, 
requires more time and inconvenience than most individuals are willing or 
capable of allowing. Furthermore, the cost of maintaining a sufficient 
supply of these products creates an additional burden. Consequently, 
electric dry shavers have become increasingly popular, as well as 
battery-operated electric dry shavers which can withstand exposure to 
moisture, thereby enabling individuals to simultaneously shower, as well 
as shave either beards or legs. 
As the popularity of electric dry shavers increased, various product 
designs and alternate constructions proliferated, in an attempt to improve 
and enhance the comfort and cutting efficiency of such shavers. However, 
in spite of these product changes, difficulties have continued to exist in 
providing optimum results with optimum comfort. 
One particular configuration has been found to be extremely efficacious in 
achieving high quality shaving results, as well as being extremely 
comfortable to use. This configuration comprises the various models of 
electric dry shavers incorporating a movable cutting blade which 
cooperates with a thin, flexible mesh screen, or apertured foil. 
In operation, the cutting blades are rapidly and continuously 
reciprocatingly moved against one side of the mesh screen or apertured 
foil, causing the cutting blades to repeatedly cross the plurality of 
apertures and provide a virtually continuous cutting action at each 
aperture. Then, by sliding or guiding the other side of the mesh screen or 
apertured foil over the skin surface to be shaved, the individual hair 
shafts enter the holes formed in the screen or foil and are cut by the 
movement of the cutting blades. 
Although this dry shaving cutting system has proven to be extremely 
effective, as compared to other dry shaving products, one area of 
difficulty does exist. In certain instances, as the mesh screen or 
apertured foil is moved over the skin surface in order to attain the 
desired cutting action, the contours of the skin act upon the apertured 
foil, causing the foil to deflect. Since the cutting blades are in 
intimate contact with the opposed side of &the apertured foil, the 
deflection of the foil also causes the cutting blades to be simultaneously 
deflected therewith. 
Unfortunately, at certain times, the apertured foil and the cutting blades 
do not simultaneously move in completely identical directions and, as a 
result, the cutting blade is moved out of intimate, contacting, cutting 
engagement with at least a portion of the surface of the apertured foil. 
When any such separation occurs, the movement of the cutting blade is 
incapable of attaining the requisite cutting action against the surface of 
the apertured foil, causing discomfort to the user as well as resulting in 
unshaven areas. 
In an attempt to reduce or eliminate the tendency of the apertured foil 
from flexibly separating from the cutting blades, most apertured foils 
have been constructed with the apertures or holes formed in the foil, 
lying in rows which are angularly biased relative to the cutting edges of 
the cutting blades. This angular biased relationship has been employed to 
reduce or eliminate the possibility of adjacent holes cutting at the same 
time, since it was found that simultaneous cutting of hair follicles by 
adjacent holes tended to cause the apertured foil to deflect. 
Although it is now generally accepted to arrange the apertures or holes in 
rows which are biased to the cutting edges of the cutting blade, the 
difficulties and drawbacks resulting from the foil being flexed out of 
contact with the cutting edges of the cutting blade continues to exist. 
Attempts to resolve this continuing problem have resulted in a plurality 
of alternate configurations and arrangements being employed for the 
apertures or hole patterns. However, these various prior art constructions 
have been incapable of eliminating the problems, and separation of the 
apertured foil from the cutting surface continues in these prior art 
units, with discomfort and unshaven areas resulting therefrom. 
Consequently, it is a principal object of the present invention to provide 
an apertured foil construction for electric dry shavers wherein unwanted 
disassociation of the apertured foil from the cutting blade is 
substantially reduced and virtually eliminated. 
Another object of the present invention is to provide an apertured foil for 
electric dry shavers having the characteristic features described above 
which is capable of providing substantially improved comfort and shaving 
efficiency, while also providing enhanced and improved results. 
Another object of the present invention is to provide an apertured foil for 
electric dry shavers having the characteristic features described above 
which is capable of Virtually eliminating areas where the shaver is 
incapable of cutting the desired hair due to the contours of the surface 
being shaved. 
A further object of the present invention is to provide an improved 
apertured foil for electric dry shavers having the characteristic features 
described above which virtually eliminates unwanted unshaven areas. 
Other and more specific objects will in part be obvious and will in part 
appear hereinafter. 
SUMMARY OF THE INVENTION 
The prior art difficulties and drawbacks have been virtually eliminated by 
constructing an apertured foil wherein the natural radius of curvature of 
the apertured foil is defined by an elongated axis which is parallel to 
the longitudinal axis of the cutting blades. It has been found that the 
apertured foil of the present invention naturally wraps tightly about the 
cutting edges of the cutting blades and remains in close, following, 
contacting engagement with the cutting edges during use, due to the 
inherent construction of the apertured foil, wherein the natural radius of 
curvature thereof follows the curvature of the cutting edges of the 
cutting blade. 
In the preferred embodiment, each of the apertures or holes formed in the 
foil lie in laterally extending, elongated rows which are biased or sloped 
relative to the plane of the cutting blades. Although a biased or sloping 
row pattern is commonly found in prior art structures, such prior art 
structures have been found to comprise a natural radius of curvature which 
is defined by a longitudinal axis which forms an acute angle with the 
plane of the cutting blades, as well as the longitudinal axis of the 
cutting blade assembly. For this reason, the prior art constructions have 
been incapable of providing the desired close, following, continuing 
contacting engagement between the apertured foil and the cutting blades. 
By eliminating the prior art natural radius of curvature, the apertured 
foils of the present invention achieve an apertured foil which naturally, 
peripherally surrounds and closely drapes about the cutting edges of the 
cutting blade in closely contacting, following interengagement therewith. 
As a result, the inherent tendency of the foil to separate from the 
cutting edges of the cutting blades is eliminated. 
In the present invention, the apertured foil has a natural radius of 
curvature which is perpendicular to the plane of the cutting blades and 
co-parallel to the longitudinal axis along which the cutting blade 
assembly reciprocatingly moves. In order to attain this unique 
construction, the laterally extending, elongated rows of apertures are 
alternatingly staggered to provide aperture alignment in every successive 
alternating row, extending from one lateral edge to the opposed lateral 
edge in at least the principal cutting area. In this way, a plurality of 
longitudinally extending axes are formed for each aligned group of 
apertures formed in the foil. 
As a result of this construction, the entire apertured foil comprises a 
natural radius of curvature which is parallel to the elongated, 
longitudinally extending axis along which the blade assembly 
reciprocatingly moves. In this way, close contacting interengagement of 
the apertured foil with the cutting edges of the blade assembly is 
maintained throughout the shaving use and substantially enhanced results 
are realized. 
The invention accordingly comprises an article of manufacture possessing 
the features, properties and relation of elements which will be 
exemplified in the article hereinafter described and the scope of the 
invention will be indicated in the claims.

DETAILED DISCLOSURE 
In FIGS. 1-6, the preferred embodiment of apertured foil 20 of the present 
invention is depicted in detail. As shown throughout the drawings, 
apertured foil 20 comprises a thin sheet of flexible material 21, 
preferably metallic in composition, which incorporates a plurality of 
apertures 22 formed therein. Apertured foil 20 incorporates side edges 23 
and 24 and mounting plates 28 and 29 secured to the remaining opposed 
edges thereof. As detailed below, apertures 22 have a unique construction 
and are arranged in a specific pattern, relative to each other in order to 
attain the desired enhanced cutting effect. 
In the embodiment depicted in FIG. 1, apertured foil 20 incorporates two 
separate, virtually identical zones 25 and 26, each of which incorporate a 
virtually identical pattern of apertures 22. Apertures 22 of zones 25 and 
26 form the beard engaging and cutting surface of apertured foil 20. By 
employing this configuration, zones 25 and 26 form dual arcuately curved 
cutting surfaces, as shown in FIG. 4. 
It has been found that the dual arcuately curved construction maximizes the 
effective surface cutting area and provides both a smooth and comfortable 
shaving system. However, if desired, the apertured construction of the 
present invention can be employed in single arcuately curved constructions 
without departing from the scope of this invention. 
Apertured foil 20 cooperates with blade assembly 3 which is constructed for 
rapid, side-to-side reciprocating movement. As shown in FIG. 4, blade 
assembly 33 comprises a plurality of independent, substantially 
identically shaped cutting blades 34, each of which are aligned in 
juxtaposed, spaced, parallel facing relationship to each other and 
comprise cutting edges 35. As a result, blade assembly 33 comprises an 
elongated, longitudinally extending construction having a central 
longitudinal axis 36. 
When mounted in frictional, contacting, cutting interengagement with the 
inside surface of apertured foil 20, blade assembly 33 reciprocatingly 
moves along central elongated longitudinal axis 36. In addition, in the 
preferred embodiment, M-shaped cutting blades 34 are positioned with 
cutting edges 35 thereof in frictional, contacting interengagement with 
zones 25 and 26 of apertured foil 20. In this way, the desired cutting 
action is attained for providing the desired clean shaven result. 
Although blade assembly 33 preferably comprises M-shaped cutting blades 34, 
in order to enable apertured foil 20 to comprise a dual curved surface 
comprising zones 25 and 26, blade assembly 33 can be formed with the 
cutting blades having a single arcuately curved surface, for mating, 
contacting, frictional cutting interengagement with a single arcuately 
curved surface of a cooperating apertured foil. However, regardless of 
which cutting blade configuration is employed, the teaching of this 
invention can be used with equal efficacy. 
In use, the outside surface of apertured foil 20 is rubbed across the skin 
surface to be shaven, in order to allow the tiny hairs extending from the 
skin surface to enter apertures 22 and be severed by the movement of the 
cutting edges 35 across the opposed surface of foil 20. In this way, 
removal of the beard or hair is attained and the desired clean shaven 
result is realized. 
As detailed above, one of the difficulties encountered in prior art 
constructions is the inability of the prior art apertured foil members to 
remain in intimate, frictional engagement with the cutting edges of the 
cutting blade. However, by employing the present invention, the prior art 
drawbacks are eliminated and substantially continuous, trouble-free 
contacting engagement of apertured foil 20 with cutting edges 35 of blade 
assembly 33 is achieved. 
One of the principal drawbacks of prior art apertured foil configurations 
is the failure of these prior art foils to possess a natural radius of 
curvature, whose axis is parallel to axis 36 along which blade assembly 33 
moves. However, as detailed herein, the present invention overcomes this 
prior art problem. 
In the present invention, zone 25 of apertured foil 20 comprises a natural 
radius of curvature defined by axis 40. Similarly, the natural radius of 
curvature of zone 26 of apertured foil 20 is defined by axis 41. As 
evident in FIGURE 4, both axes 40 and 41 are parallel to each other as 
well as parallel to the longitudinal axis 36 of blade assembly 33. 
By achieving apertured foil 20 with zones 25 and 26 each having normal or 
natural radii of curvature which are parallel to longitudinal axis 36 
along which blade assembly 3 reciprocatingly moves, apertured foil 20 
possesses arcuate curved zones 25 and 26 which naturally peripherally 
surround and continuously embracingly contact cutting edges 35 of blade 
assembly 33. As a result, when the outer surface of arcuate zones 25 and 
26 are moved over the skin surface being shaven, apertured foil 20 remains 
in frictional contacting engagement. with cutting edges 35 of blade 
assembly 33, due to the natural, inherent curvature of zones 25 and 26 of 
apertured foil 20 being congruent to the arcuate curved cutting edges 35 
of blade assembly 33. 
In prior art constructions, the movement of the apertured foil along the 
skin surface to be shaven causes the apertured foil to flex and seek its 
natural radius of curvature, thereby separating the foil from the cutting 
edges. To the contrary, apertured foil 20 of the present invention remains 
in the precisely desired curved configuration, conforming to the curvature 
of the cutting edges since its natural radius of curvature is congruent to 
the radius of curvature of cutting edges 35 of blade assembly 33. As a 
result, smooth, troublefree, comfortable shaving of the desired surface is 
attained. 
In order to provide apertured foil 20 of the present invention with a 
natural radius of curvature congruent to the radius of curvature of the 
arcuate cutting edges 35 of blade assembly 33, apertures 22 of apertured 
foil 20 are constructed in a specific hole configuration, as well as being 
arranged in a specific side-to-side hole pattern. By referring to FIGS. 1 
and 3, along with the following detailed disclosure, this side-to-side 
arrangement can best be understood. 
In the preferred embodiment, apertures 22 are each constructed with a 
generally rhombic shape with each side thereof having an overall length of 
about 0.016 inches. Although the size of each aperture 22 can range 
between about 0.012 and 0.020 inches, a dimension of 0.016 inches is 
preferred. 
In addition, apertures 22 are positioned in side by side adjacent 
relationship to each other forming elongated rows 45, 46, and 47 each of 
which are positioned angularly relative to side edges 23 and 24 of foil 
20. However, each of the rows 45, 46, and 47 are angularly biased with the 
identical arcuate distance, so that all of the rows formed in apertured 
foil 20 are parallel to each other. 
As shown in FIG. 3, rows 45, 46, and 47 are each angularly disposed 
relative to side edge 24 by an arcuate distance equal to "X". In the 
preferred embodiment, "X" equals between about 6.degree. and 10.degree. 
with 8.degree. being preferred. As discussed above, since all of the rows 
formed in aperture foil 20 are parallel to each other, each row thereof 
comprises the identical arcuate spacing relative to side edge 24. 
In the preferred embodiment, sixteen apertures are positioned in side by 
side relationship to form rows 45, 46, and 47. Although each of the rows 
incorporate the identical number of apertures, the position and spacing of 
the apertures relative to each other vary to attain a specific 
configuration for each of the rows 45, 46, and 47. 
The apertures of particular importance in attaining apertured foil 20 which 
provides the enhanced comfortable and close shaving results, are the 
apertures forming the central portion of zones 25 and 26. In FIG. 3, zone 
"B" is clearly depicted, showing the area in which the positioning and 
alignment of apertures 22 is of greatest concern. 
In zone "B", each row 45, 46, and 47 incorporates eleven apertures 22. 
Furthermore, each of the apertures in each row is spaced apart from the 
adjacent aperture in its row by a distance of 0.008 inches. Although this 
dimension may vary between about 0.006 and 0.010 inches, the preferred 
dimension is 0.008 inches. 
In addition, rows 45, 46 and 47 are preferably spaced apart from each other 
a distance of about 0.011 inches. However, this spacing may range between 
about 0.008 and 0.014 inches. In row 45, aperture 50 is the first aperture 
within zone "B", while aperture 51 is the last aperture of row 45 in zone 
"B". Similarly, in row 56, aperture 53 is the first aperture in zone "B", 
while aperture 54 is the last aperture in zone "B". Finally, in row 47, 
aperture 55 is the first aperture in zone "B", while aperture 56 is the 
last aperture in zone "B". 
As detailed above, all of the apertures extending from apertures 50 to 51, 
comprise the identical dimensions while also being spaced apart from each 
other with identical distances. Similarly, all of the apertures between 
and including aperture 53 to aperture 54 all comprise identical dimensions 
with identical spaced distances therebetween, while aperture 55 to and 
including aperture 56 are also identically dimensioned and identically 
spaced apart. 
Consequently, the overall lateral distance between aperture 53 and aperture 
54 is identical to the overall lateral distance between aperture 50 and 
aperture 51. Similarly, the overall lateral distance between aperture 55 
and aperture 56 is identical to the similar distances found in rows 45 and 
46. 
As best seen in FIG. 3, rows 45, 46 and 47 are arranged in a continuously 
repeating pattern. In the preferred embodiment, rows 45 and 47 alternate 
as the next row, with row 46 continuously repeating as the row following 
both row 45 and row 47. As a result, a row pattern of 45-46-47-46-45-46, 
etc. is attained throughout the entire available distance between edges 23 
and 24. 
Furthermore, as is more fully detailed below, rows 45 and 47 vary only in 
the position of the first aperture of the row. By providing adjacent rows 
with the position of the first aperture alternating to provide a generally 
sinusoidal pattern, as is evident from FIG. 3, an apertured foil is 
attained having greater flexibility and bendability along its lower 
terminating edges. 
In accordance with the present invention, as is clearly shown in FIG. 3, 
each aperture 50 of each row 45 and each aperture 55 of each row 47 are 
positioned in longitudinal alignment with one another, thereby defining an 
elongated, longitudinally extending axis which is parallel to the 
longitudinal axis 41 of zone 26. In addition, since each of the other 
apertures in row 45 between and including apertures 50 and 51 are all 
equidistant to each other, with all of the apertures of row 47 extending 
from apertures 55 to 56 are similarly constructed with equidistant 
spacing, each and every aperture in rows 45 and 47 in zone "B" are 
longitudinally aligned with each other to form eleven separate and 
distinct parallel longitudinally extending axes, all of which are 
coparallel to each other and longitudinally elongated axis 41 of zone 26. 
Furthermore, since the row pattern in FIG. 3 employs row 46 as a 
continuously repeating successive row, it is equally apparent that all of 
the apertures in zone "B" of each row 46 must be aligned with each other 
and thereby define eleven additional longitudinally extending axis which 
are coparallel to each other, as well as co-parallel to axis 41 of zone 
26. 
By employing this construction, each and every aperture in each alternately 
successive row in zone "B" are longitudinally aligned with each other to 
establish eleven elongated, longitudinal axes extending from edge 23 to 
edge 24. Similarly, the second, interspersed alternately successive rows 
of apertures are aligned with each other, thereby also defining an 
additional eleven longitudinal axes extending from edge 23 to edge 24. 
By providing aperture foil 20 with this particular construction, zone "B" 
incorporates twenty-two longitudinal axes defining the aligned positions 
of all of the apertures in zone "B". As a result of this construction, the 
natural radius of curvature of apertured foil 20 coincides with the 
longitudinal axes of alignment in which apertures 22 are positioned. 
Consequently, apertured foil 20 of the present invention achieves a 
natural radius of curvature, as detailed above, which enables apertured 
foil 20 to remain concavely draped about the arcuate curved cutting edges 
35 of blade assembly 33, assuring continuing, contacting interengagement 
of apertured foil 20 with cutting edges 35, regardless of the deflection 
experienced by apertured foil 20 during its use. 
The apertures forming rows 45, 46, and 47 which are outside of zone "B" are 
constructed with varying spaced distances therebetween, as each row rears 
the opposed ends of zone 26. In addition, as discussed above, the position 
of the first aperture is staggered in order to avoid complete alternate, 
side to side alignment, as is present in zone "B". 
Although the apertures in row 45 and row 47 in zone "B" are precisely 
aligned with each other, row 45 incorporates three apertures, along the 
edge directly adjacent mounting plate 29, with the opposed end of row 45 
having two apertures beyond zone "B". In contrast therewith, row 47 
incorporates two apertures along the edge of zone "B" nearest mounting 
plate 29 while the opposed end of row 47 incorporates three apertures. By 
repeating this pattern, with row 46 being repeatedly interspersed between 
rows 45 and 47, the areas of zones 25 and 26 beyond zone "B" comprise a 
uniformly staggered aperture configuration. In this way, apertured foil 20 
comprises greater flexibility and bendability for installation and use, 
while virtually eliminating breakage or fracture experienced with 
alternate configurations. 
In FIG. 5, a greatly enlarged view of the preferred construction for 
aperture 22 is shown in detail. In this preferred construction, aperture 
22 comprises two substantially straight, parallel, facing edges 61 and 62, 
while the remaining two juxtaposed, spaced, facing edges forming aperture 
22 comprise arcuately curved edges 63 and 64. In the preferred embodiment, 
edges 63 and 64 incorporate three arcuately curved zones each of which 
preferably comprise a typical radius of 0.002 inches. Although the number 
of arcuate zones and the radius employed can be varied, it has been found 
that three arcuate zones, each of which comprise a radius of 0.002 inches 
provides an extremely efficient construction. 
As is apparent from the dimensions preferably employed for arcuate edges 63 
and 64, the arcuate construction only becomes evident in a substantially 
enlarged view, as provided in FIG. 5, which represents an enlargement of 
aperture 22 of about one hundred times. Although straight edges could be 
employed to form a completely rhombic shaped aperture 22, the use of 
arcuate edges 63 and 64 are preferred. It has been found that by employing 
arcuate edges 63 and 64, aperture 22 is capable of trapping and holding 
the hair fibers to a greater extent than is generally attainable with an 
aperture having four straight edges. 
In constructing the preferred embodiment of aperture 22, straight side 
edges 61 and 62 comprise the longitudinally extending edges detailed above 
which are in juxtaposed, spaced, aligned, relationship with the apertures 
in each alternate successive row of foil 20. In this way, the desired 
natural radius of curvature detailed above is enhanced. 
As a result, arcuately curved edges 63 and 64 are arcuately sloped relative 
to the side edges of foil 20 by the arcuate distance of "X", as discussed 
above. As previously stated, this arcuate distance preferably ranges 
between 6.degree. and 10.degree., with the preferred arcuate spacing being 
8.degree.. 
Finally, in FIG. 6, a further detailed view of aperture 22 is provided. As 
shown therein, edges 63 and 64 of aperture 22 of foil 20 preferably 
incorporate a radius on the corner of the top surface thereof, forming the 
surface contacting the skin of the user. The opposed corner of edges 63 
and 64 comprise sharp corners. In this way, it has been found that the 
cutting action of cutting edges 35 of blade assembly 3 attains an improved 
clean shaven result, while providing comfort to the user. 
It will thus be seen that the objects set forth above, among those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in the above article, without departing 
from the scope of the invention, it is intended that all matter contained 
in the above description or shown in the accompanying drawings shall be 
interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cover 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.