CN1098755C - Oval frame razor - Google Patents

Abstract

A razor blade unit for a safety razor has optimised shape and dimensions for body shaving, especially the regions of the axillae. The blade unit has an elongate blade with a rectilinear sharpened edge, and a skin contacting surface at which the length is 1 to 4 times the width and not greater than 60 mm, preferably 40 to 45 mm. The skin contacting surface has a footprint area of at least 450 mm<2>, preferably 600 to 750 mm<2>, and a circularity which is not less than the lower of (i) 65 %, and (ii) the circularity of a rectangle with the same length and width as the skin contacting surface and with corner radii of 30 % of the width. In a plane perpendicular to the blade edge the skin contacting surface is convex and shaped to make at least three point contact with an imaginary circumscribing circle with a radius of 15 to 70 mm, preferably 25 mm. Guard and cap surfaces in front of and behind the blade edge each have a skin contact area of at least 140 mm<2>, and their combined areas is preferably at least 400 mm<2>, e.g. 450 to 500 mm<2>. A preferred shape is rectangular with semi-circular ends.

Description

Razor with oval frame

The present invention relates to safety razors having a blade unit supported by a handle, the blade unit comprising an elongated blade having a rectilinear sharp edge, or a plurality of parallel blades This kind of blade. The blade unit may be fixedly mounted on the handle for the purpose of throwing away the entire razor when the or each blade becomes dull. Additionally, the blade unit can be detachably attached to the handle so that a used blade unit can be replaced with a new blade unit. Replaceable blade units are commonly referred to as knife holders.

The general trend in recent years for razor blade units has been to reduce the size, particularly the surface area surrounding the blade that contacts the skin during shaving, and most currently available commercially available blade units are long and narrow, when along a substantially vertical They have a substantially rectangular configuration when viewed in the direction of the skin-contacting surface. In general, it has been found that razor blade units of this shape and size provide improved shaving performance as compared to earlier, larger sized blade units.

The object of the invention is in particular a blade unit for shaving the body, mainly in the underarm area. There are already razors on the market for ladies who often shave their underarms and similar other razors have a strong tendency to make blade units for these women's razors which have the The narrow rectangular configuration described above. It has become accepted opinion within the art that such narrow sized blade arrangements are particularly beneficial for underarm shaving because they more easily fit into the rather deep recesses of the underarms.

The present invention departs significantly from this prevailing opinion in the field of shaving and is directly in opposition to all recent developments in this technical field in terms of blade unit size. Unexpectedly, and contrary to all expectations, shaving trials have shown that not only can a relatively large size blade unit shave at least as efficiently as a smaller prior art blade unit when shaving the underarms, but also The large blade unit is shaped to conform to the underarm area of the body, so the shaving performance is not reduced, and in terms of overall comfort, the large blade unit has performance superior to prior art blade units and uses prefer. It appears that the additional stability created by a large contact area with the skin induces greater confidence in the user when shaving underarms that cannot be easily observed during shaving, and thus the user feels An improved comfort that more than offsets any loss in performance due to the large contact area.

For most adult females, the armpits have a minimum radius of curvature of about 25 to 30 mm. Accordingly, the razor blade unit of the present invention has a length of no greater than 60 mm, preferably no greater than 50 mm, and preferably a length of 40 to 45 mm. The width of the blade means is preferably such that the aspect ratio, i.e. the ratio of the overall length measured perpendicular to the blade to the overall width, is in the range of 1-4, and in most preferred embodiments of the invention the aspect ratio is 1.5 -2.8, more precisely in the 2.0-2.5 range. In preferred embodiments, the blade arrangement has a width of 12-23 mm, especially 15-20 mm. The surfaces of the guard and the cover are defined at the front and back of the or each blade so as to contact the skin at the front and the back of the or each blade during shaving, and preferably the surfaces of each guard and the cover have A width of not less than 4.0 mm, at least where the width of the blade arrangement is at its largest. The protector and cover each have a skin contact area of preferably not less than 140 mm ² and the total skin contact area of the cover and protector is preferably at least 400 mm ² and most preferably in the range of 450 to 500 mm ² . Because the blade device of the present invention is quite wide, so in order to facilitate contact with the skin of the underarm over at least most of the guard and cover area, as seen in a cross-section in a plane perpendicular to the blade, the contact The surface of the skin is made convex. It is important to understand that the term "convex" as used in this specification does not necessarily mean that the skin-contacting surface is smoothly curved, it only means that the guard and cover surfaces are curved from their The direction of the edge of the or each blade extends upwards so that the or each edge is at a height above the outer edge of the cover and protector surface. More specifically, a straight line joining the outer and inner extents of each guard and cover surface is inclined at an angle of at least 5°, and possibly as much as 25°, to a plane that is in contact with the skin immediately in front of and behind the blade tangent to the surface. In this preferred embodiment, the angle of inclination is in the range of 10 to 20°, more precisely equal to substantially 15°. Depending on the convexity of the skin-contacting surface, the blade unit is preferably shaped so that at least three points are in contact with an imaginary circumcircle having a diameter of 30 to 100 mm, preferably about 50 mm , so that it will ensure that the blade unit is at least approximately as convex as the underarm.

An important aspect of the blade unit of the present invention is that it forms a large area that can come into contact with the skin during shaving, and a circumscribing perimeter extending around the skin-contacting surface limits an ^area of at least 450 mm , This area is hereinafter referred to as "track area". The most preferred track area is in the range of ^600-750m2 , more precisely between ^650-720mm2 .

Since the present invention proposes a blade device having a long and wide shape, a substantially rectangular configuration with sharp corners at least at the edges adjacent the guard surface is unsuitable. In the context of this specification, an acute corner is considered to be an angle of less than about 120° with a radius of curvature of less than about 3mm. Preferably a curvature of at least 5mm at any corner. The unacceptability of a substantially rectangular configuration and the purpose of providing a large skin contact area means that the blade unit needs to be profiled, as seen in a plane substantially perpendicular to the skin contact area, so that A relatively large area is obtained over the total length and width dimensions. The "roundness" of a two-dimensional shape is a convenient way of relating the area enclosed by its perimeter to the length of that perimeter, and expressing it as a percentage of a circle which, for any given perimeter length, Always provide the largest area. Therefore, the roundness of any shape is determined by the following formula:

In the formula: A = area

P = peripheral

The roundness of the razor blade units of the present invention is not less than the lesser of (a) and (b), where (a) is 65%, and (b) is as long and wide as the area in contact with the skin and has Roundness of the area of a substantially rectangle with a corner radius of 30% of said width. Preferably the roundness is greater than that of a rectangle having the same overall length and overall width, and the rounded corners have a radius equal to 10% of the length. For blade arrangements having a low aspect ratio (i.e. less than about 3), the lower limit (a) will be used, although even in the case of these blade arrangements it is preferable that the roundness exceeds limit (b) . An elliptical blade arrangement with an acceptable aspect ratio above 3.25 may have a roundness of less than 65%. Preferred embodiments with aspect ratios below about 2.75 have a circularity greater than 70%, more specifically about 80%. Typical prior art blade arrangements have a roundness of less than 65%. The relatively large roundness of a blade arrangement according to the invention can be achieved with a rounded corner at the end of the blade arrangement, which has a relatively large radius of curvature of at least 6mm, or with an oval, ellipse or polygonal shapes, which do not necessarily have to be symmetrical.

According to the foregoing, the present invention pertains to a razor blade unit comprising at least one elongated blade having a rectilinear sharp edge mounted in a substantially inflexible frame, a The skin-contacting surface surrounds the one or more blades and includes the guard and the surface of the cover on opposite sides of the one or more blades, the skin-contacting surface having a length-to-width aspect ratio in the range of 1 to 4 the skin-contacting surface is convex as viewed in cross-section in a plane perpendicular to the blade or blades, the total length of the blade means at the skin-contacting surface is not greater than 60 mm, The skin-contacting surface has a circumscribed perimeter defining a track area of at least ⁴⁵⁰ mm, and the circumscribed perimeter is shaped such that the track area defined by the perimeter has a roundness (eg above), the roundness is not less than the lesser of (a) and (b), where (a) is 65%, and (b) is as long and wide as the area in contact with the skin and has the upper The roundness of the substantially rectangular area of the corner radius of said width 30%, and the edge of the blade means adjacent to the guard surface is free of sharp corners.

In shaving trials it has been found that a razor equipped with the above described blade arrangement provides a marked improvement in overall performance when shaving the underarms and has also been found to be very effective when shaving other parts of the body such as the legs .

It should be understood that unless otherwise stated, all dimensions and areas quoted herein are measured in a projected plane, and that the effect of the convex curvature of the skin-contacting surface of the blade unit as seen in the plan view has been disregarded. Determine the relevant dimensional data.

To further illustrate the present invention, certain forms of razor blade units formed and dimensioned in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

1-9 are schematic plan views of razor blade assemblies embodying the present invention;

Figure 10 is a graph showing circularity plotted against aspect ratio (maximum length/maximum width) and showing the results for the blade arrangements of Figures 1-9 and for certain prior art blade arrangements;

Figure 11 is a schematic cross-section through the blade arrangement of Figure 1;

Figure 12 shows a modified shape for the guard and cover surface of the blade assembly of Figure 1;

Fig. 13 shows the blade sheath of a kind of blade device as shown in Fig. 1 in perspective view form;

Figure 14 shows the blade assembly as shown in Figure 1 in a partial perspective view and has the same guard and cover surface as in the Figure 13 embodiment; and

Figures 15 and 16 are views corresponding to Figure 14, showing two and three forward facing blades, respectively.

Each of the blade assemblies shown in Figures 1-9 includes a blade guard comprising a substantially inflexible blade support frame conveniently molded of plastics material. The sheath defines a skin-contacting area surrounding the elongated rectangular slit 2, and houses a sharp, straight-edged blade (not shown in Figures 1-9) within the sheath. A single blade may be provided in the slot 2, but preferably two or more blades with parallel sharp edges are installed. In the particular embodiment shown in Figure 14, there are three blades, two facing forwards and one facing backwards, so the razor blade unit will shave in both directions, although forward across the skin Moving will generally provide a slightly better result. Figure 15 shows an embodiment with two blades in tandem tandem, while Figure 16 shows another embodiment with three blades with parallel edges all facing forward. Each of the blade units in Figures 1-9 may be considered to be suitable for accommodating two blades, or three blades similar to the blade installation in Figure 14 or all in tandem tandem. The blade guard in each of the embodiments shown in Figures 1-9 has a guard area 3 and a cover area 4, the guard area 3 being positioned in front of the blade slot (as seen in the figures). Below), while the cover area 4 is located behind the blade slit 2 (upper in the drawings).

The particular blade arrangement in Figure 1 is oval and has a rectangular shape with semicircular ends. Dimensions measured in projected plan view shown are as follows:

Total length = 42.0mm

Total width ＝18.0mm

End radius ＝9.0mm

Protection device area = 206mm ²

Cover area = 277mm ²

Total skin contact area = 504mm ²

Total track area within perimeter = 686mm ²

The blade arrangement of Figure 2 is approximately rectangular with corners having a large radius of curvature. The specific dimensions used for this example are:

Total length = 41.0mm

Total width ＝18.0mm

Corner radius = 6.0mm

Protection device area = 213mm ²

Cover area = 286mm ²

Total skin contact area = 520mm ²

Total track area within perimeter = 703mm ²

Figure 3 shows an asymmetric configuration of the blade unit. At both ends of the blade unit front edge are rounded corners of large radius (as in Figure 2), while the corners at both ends of the rear edge are rounded with a significantly larger radius of curvature.

Its specific dimensions are:

Total length = 40.0mm

Total width ＝18.0mm

Front corner radius = 6.0mm

The radius of the rear end = 10.0mm

Protection device area = 185mm ²

Cover area = 283mm ²

Total skin contact area = 488mm ²

Total track area within perimeter = 668mm ²

Figures 4-6 show blade assemblies whose sheaths have the same overall shape and dimensions as the sheath shown in Figure 1, but with a different location of the blade slit. In Figure 4 the slit is positioned such that the guard area and cover area are equal, while in Figure 5 the slit is positioned such that the cover area is significantly smaller than the guard area (but still at least ^140mm2 ), in Figure 6, the slit is positioned such that the protector area is significantly smaller than the cover area (but still at least 140mm ² ).

Fig. 7 shows a polygonal blade arrangement which is substantially shaped as a rectangle with chamfered corners 7 having an angle of 135° to the longitudinal front and rear edges and to both ends face. In the case of a blade arrangement having an overall length of 42 mm and an overall width of 18 mm, the chamfer may lie along a diagonal of a square having dimensions 5 mm x 5 mm.

All of the embodiments of Figures 1-7 have rectilinear front and rear edge portions that are parallel to one or more cutting edges for at least a substantial portion of the blade length. This may be ideal for easy orientation of the blade unit and to help the user know which direction the blade unit should move on the skin. However, this is not essential and other configurations can be used to achieve the dimensional criteria of a blade unit embodying the invention. For example. Figure 8 shows an elliptical profile blade arrangement, and even a circular shape as shown in Figure 9 is possible, although it is not the most ideal embodiment.

Figure 10 shows a graph showing circularity versus aspect ratio (ie maximum length/maximum width of the blade arrangement). The points representing each blade assembly of Figures 1-9 are represented by (1)...(9), the points representing three prior art women's razor blade assemblies purchased from the market recently are represented by A, B, and C, and the points representing A square of dots is denoted by S for comparison purposes. A line R _w runs substantially diagonally across the curve, which line R _w represents a rectangle with a corner radius of 30% of the width of the rectangle. The rectangle represented by the dashed line _RL has a corner radius of 10% of the length of the rectangle. A horizontal line is drawn at a circularity of 65%. It can be seen that all the preferred embodiments of the invention represented on this graph have aspect ratios between 1.5 and 2.8, and for the majority the aspect ratios are in the range 2.0-2.5. Furthermore, each embodiment of the present invention has a circularity greater than that of a corresponding rectangle having the same aspect ratio, and has a radius between 10% of the rectangle's length ( _RL ) or 30% of the rectangle's width ( _Rw ). rounded corners. Furthermore, the various embodiments of the present invention have greater roundness than prior art blade arrangements, and those roundnesses included on the graph all have values in excess of 60%, more precisely, values in excess of 70% . (It should be remembered that there are two points (8) shown in Figure 10 describing two additional elliptical shapes).

In all embodiments of the present invention, the skin-contacting surfaces are not planar, and the views of Figs. 1-9 are projected planar regions only. The planes are preferably shaped so that at least three points (and ideally at least four points) touch an imaginary circumscribed circle of radius 25mm. FIG. 11 shows this preferred relationship for a blade, which may for example be the blade arrangement of FIG. 1 . An imaginary circle is drawn with dashed lines, and it can be seen that the surfaces of the cover and protector generally conform to this circle. In FIG. 11 , the guard and cover surfaces are generally flat, but they may be convexly curved to provide an even closer conformity, for example, as depicted in the schematic diagram of FIG. 12 . The surfaces of the cover and guard are inclined towards a plane P which is the "shaving surface" tangent to the skin contacting surfaces just in front of and behind the one or more blades, in the exemplary embodiment shown tangent at an angle of 15°. In any particular embodiment, the most suitable bevel angle will depend on the width of the blade unit and be selected accordingly, but for most embodiments of the invention at least one angle in the range of 10-20° will be required , to ensure close agreement with the imagined circle. In the case of a convex guard and/or cover surface, as in Figure 12, it is appropriate to take into account the slope of a chord line intersecting the edges of the relevant surface closest and furthest to the adjacent blade.

In Fig. 13, a preferred form of blade unit sheath is shown. It has a frame 10 defining a slot 2 to accommodate the blades and components securing them in the frame. Mounted on the frame are parts of the protector and cover, each having an elastic surface element 12 defining a skin contact area formed by a row of cylindrical depressions 13, the Cylindrical dimples 13 are spread evenly over substantially the entire surface. For ease of manufacture and assembly, the elastic element is mounted on a support 14 firmly fixed in the frame 10 . Figures 14, 15 and 16 show a modified structure in which the elastic member 12 is directly supported by the frame 10 of the blade unit. The figures also show the blades 15 fitted within the frame, and a retaining clip 16 provided at each end of the blade unit to hold the blades in place.

It is important to note that, as previously stated, all dimensions cited in the specification and claims of this specification with respect to length, width and area are based on the shape of the blade unit projected onto a plane of the skin-contacting surface , which is parallel to the plane of the shaved surface, ie the plane indicated by P in FIG. 11 . Furthermore, any minor irregularities in the perimeter, for example due to small indentations, such as narrow notches or protrusions, which can significantly alter the perimeter without substantially changing the area, should be disregarded when calculating the roundness .

Claims (181)

1. A razor blade assembly comprising at least one elongated blade having a rectilinearly sharpened edge mounted on a substantially fixed frame, a skin contacting surface surrounding the one or more blades and comprising Surfaces of the guard and cover on opposite sides of the one or more blades, the skin-contacting surface has a length/width aspect ratio in the range of 1-4, in a plane perpendicular to the one or more blades The skin-contacting surface is convex, the total length of the blade means at the skin-contacting surface is not greater than 60 mm, as seen in cross-section, the skin-contacting surface has a circumscribed perimeter defining a A track area of 450 ^mm2 , and the circumscribed perimeter is so shaped that the track area bounded by said perimeter has a roundness not less than the lesser of the two values (a) and (b) , wherein (a) is 65%, and (b) is the roundness of a substantially rectangular area having the same length and width as the track area of the skin-contacting surface and having a corner radius of 30% of said width. 2. The blade unit of claim 1, wherein the edge of the blade unit adjacent the surface of the guard has no sharp corners. 3. The blade device according to claim 1, wherein the track area is in the range of 600-750 mm ² . 4. The blade device according to claim 3, wherein the track area is in the range of 650-720 mm ² . 5. The blade unit according to any one of claims 1 to 4, wherein the total length of the blade unit at the skin-contacting surface is not greater than 50 mm. 6. The blade device according to any one of claims 1 to 4, wherein the aspect ratio of the length to the width is in the range of 1.5-2.8. 7. The blade device according to claim 6, wherein the aspect ratio is in the range of 2.0-2.5. 8. The blade unit according to any one of claims 1 to 4, wherein each of the surfaces of the guard and the cover has an area of at least 140 mm and is at a position where the ^width of a blade unit is at its maximum , each of the guard and cover surfaces has a width of at least 4.0 mm. 9. The blade unit according to any one of claims 1 to 4, wherein the maximum width of the blade unit is in the range of 12-23 mm. 10. The blade device according to claim 9, wherein the maximum width is in the range of 15-20 mm. 11. The blade unit according to any one of claims 1 to 4, wherein the total area of the surface of the guard and the cover is at least 400 mm ² . 12. The blade device according to claim 11, wherein the total area of the surface of the protective device and the cover is in the range of 450-500 mm ² . 13. The blade unit according to any one of claims 1 to 4, wherein each of the surfaces of the guard and the cover is arranged so as to pass therethrough from the nearest and the closest to one or more blades A straight line of the far edge is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 14. The blade unit according to claim 13, wherein the angle of inclination to each of the surfaces of the guard and the cover is in the range of 10[deg.]-20[deg.]. 15. The blade device according to one of claims 1 to 4, wherein the skin-contacting surface is shaped in cross-section so that at least three points and an imaginary circumcircle with a radius of 15-70 mm touch. 16. The blade device of claim 15, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle of radius 25mm. 17. The blade device of claim 16, wherein the skin-contacting surface is machined to approximately conform to said imaginary circle on the surface of the guard and cover. 18. The blade assembly of any one of claims 1 to 4, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 19. The blade device according to one of claims 1 to 4, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness greater than a substantially rectangular area of roundness, the The rectangular area has the same overall length and overall width as the skin-contacting surface, with corner radii of 10% of that length. 20. The blade device according to any one of claims 1 to 4, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle , the rectangle has the same overall length and overall width as the skin-contacting surface, and has a corner radius that is 30% of the width. 21. The blade unit according to any one of claims 1 to 4, wherein at least one of the front and rear edges of the blade unit comprises a straight line portion and smoothly curved corner portions, the straight line portion along A major portion of the length of the blade extends parallel thereto, the corner portions being located at one end of the straight portion. 22. The blade unit of claim 21, wherein said corner portion has a radius of curvature of at least 6mm. 23. The blade means of claim 21, wherein the blade means has a semi-circular end. 24. The blade device of any one of claims 1 to 4, wherein the skin-contacting surface has an oval shape. 25. The blade unit according to any one of claims 1 to 4, characterized in that the surface of the guard and the cover are formed by elastic elements. 26. Blade means according to claim 25, wherein the resilient member defines a surface having a plurality of dimples distributed over said surfaces. 27. The blade unit of any one of claims 1 to 4, wherein at least two blades have forwardly directed cutting edges, the two blades being mounted in a blade holder. 28. A razor blade device comprising: a plurality of elongated blades having longitudinally elongated sharp edges permanently spaced apart from a bracket, a skin-contacting surface surrounding the blade sharp edge and comprising a skin-contact guard and a cover surface, the skin-contact guard being on the front side and a skin-contacting cover surface being on the rear side of the blade unit, A plurality of blades are located between the skin contact guard on the front side and the skin contact cover surface on the rear side and have sharpened blades each facing the skin contact guard in the same direction so that during the shaving shock, The protective surface, the sharp edges of several blades, and the cover surface are in contact with the skin in turn, the skin-contacting surface has an aspect ratio of length to width in the range of 1:1 to 4:1, At least one of the lid surface and the skin-contacting surface is convex in a cross-section in a plane perpendicular to the blade, the total length of the blade unit at the skin-contacting surface is not greater than 60 mm, The skin-contacting surface has a circumscribing perimeter defining a track area of at least 450 mm ² , The guard surface has an area within the track area of at least 140 mm ² and at least about 18.6% track area. 29. The blade device of claim 28, wherein the aspect ratio of the length to width of the skin-contacting surface does not exceed 3.25:1, and the circumscribed perimeter has a shape such that the locus area defined by the circumscribed perimeter has a circle Spend. 30. A blade arrangement as claimed in claim 28 or 29, wherein the cover surface is spaced behind a plurality of blades. 31. A blade arrangement as claimed in claim 28 or 29, wherein the blade sharpened edge has a straight line. 32. A blade unit as claimed in claim 28 or 29, wherein the bracket is fixed in nature. 33. The blade unit according to claim 28 or 29, further comprising a clamp for mounting the plurality of blades on the bracket. 34. The blade arrangement of claim 30, wherein the blade sharpened edge has a rectilinearity. 35. The blade assembly of claim 30, wherein the bracket is fixed in nature. 36. The blade assembly of claim 31, wherein the bracket is fixed in nature. 37. The blade assembly of claim 30, wherein the bracket is fixed in nature. 38. The blade assembly of claim 31, wherein the bracket is fixed in nature. 39. The blade assembly of claim 32, wherein the bracket is fixed in nature. 40. The blade assembly of claim 5, wherein the overall length of the blade at the skin contacting surface is in the range of 40-45 mm. 41. The blade arrangement according to claim 2, wherein the track area is in the range of ^600-750mm2 . 42. The blade unit of claim 5, wherein each of the surfaces of the guard and the cover has an area of at least 140 mm ² , and at a position where the width of a blade unit is maximum, the guard and the cover Each of the surfaces of the cover has a width of at least 4.0 mm. 43. The blade unit of claim 6, wherein each of the surfaces of the guard and the cover has an area of at least 140mm ² , and at a position where the width of a blade unit is maximum, the guard and the cover Each of the surfaces of the cover has a width of at least 4.0 mm. 44. The blade unit of claim 7, wherein each of the guard and the surface of the cover has an area of at least 140 mm ² , and at a position where the width of a blade unit is maximum, the guard and the cover Each of the surfaces of the cover has a width of at least 4.0 mm. 45. The blade unit of claim 5, wherein the blade unit has a maximum width in the range of 12-23 mm. 46. The blade unit of claim 6, wherein the blade unit has a maximum width in the range of 12-23 mm. 47. The blade unit of claim 7, wherein the blade unit has a maximum width in the range of 12-23 mm. 48. The blade unit of claim 8, wherein the blade unit has a maximum width in the range of 12-23 mm. 49. The blade assembly of claim 5, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 50. The blade assembly of claim 6, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 51. The blade assembly of claim 7, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 52. The blade assembly of claim 8, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 53. The blade assembly of claim 9, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 54. The blade assembly of claim 10, wherein the total area of the guard and cover surfaces is at least ^400mm2 . 55. The blade unit of claim 5, wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 56. The blade unit of claim 6, wherein each of the surfaces of the guard and the cover is arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 57. The blade unit of claim 7, wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 58. The blade unit of claim 8 , wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 59. The blade unit of claim 9, wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 60. The blade unit of claim 10, wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 61. The blade unit of claim 11 , wherein each of the surfaces of the guard and the cover is arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 62. The blade unit of claim 12 , wherein each of the surfaces of the guard and the cover are arranged so as to pass through one of its nearest and farthest edges from the one or more blades. The line is inclined at an angle of at least 5° to a plane that is tangent to the skin-contacting surface just in front of and behind the one or more blades. 63. The blade device of claim 5, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 64. The blade device of claim 6, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 65. The blade device of claim 7, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 66. The blade device of claim 8, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 67. The blade device of claim 9, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 68. The blade device of claim 10, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 69. The blade device of claim 11, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 70. The blade device of claim 12, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 71. The blade device of claim 13, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 72. The blade device of claim 14, wherein the skin-contacting surface is shaped in cross-section so as to bring at least three points into contact with an imaginary circumscribed circle having a radius of 15-70 mm. 73. The blade assembly of claim 5, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 74. The blade assembly of claim 6, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 75. The blade assembly of claim 7, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 76. The blade assembly of claim 8, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 77. The blade assembly of claim 9, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 78. The blade assembly of claim 10, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 79. The blade assembly of claim 11, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 80. The blade assembly of claim 12, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 81. The blade assembly of claim 13, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 82. The blade assembly of claim 14, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 83. The blade assembly of claim 15, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 84. The blade assembly of claim 17, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a roundness in the range of 70%-85%. 85. The blade device of claim 5, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 86. The blade device of claim 6, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 87. The blade device of claim 7, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 88. The blade device of claim 8, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 89. The blade device of claim 9, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 90. The blade device of claim 10, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a circularity of a substantially rectangular area having the same shape as the rectangular area. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 91. The blade device of claim 11 , wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 92. The blade device of claim 12 , wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 93. The blade device of claim 13, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 94. The blade device of claim 14, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 95. The blade device of claim 15, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 96. The blade device of claim 17, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 97. The blade device of claim 18, wherein the area defined by the circumscribed perimeter of the skin-contacting surface has a circularity greater than a substantially rectangular area having a circularity equal to the area of the rectangle. The skin-contacting surfaces have the same overall length and overall width, and have corner radii that are 10% of that length. 98. The blade device of claim 5, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 99. The blade device of claim 6, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 100. The blade device of claim 7, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 101. The blade device of claim 8, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 102. The blade device of claim 9, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 103. The blade device of claim 10, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 104. The blade device of claim 11 , wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 105. The blade device of claim 12, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 106. The blade device of claim 13, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 107. The blade device of claim 14, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 108. The blade device of claim 15, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 109. The blade device of claim 17, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 110. The blade device of claim 18, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 111. The blade device of claim 19, wherein the aspect ratio is less than 3, and the circularity of the area defined by the circumscribed perimeter of the skin-contacting surface is greater than the circularity of a rectangle having the same shape as The skin-contacting surfaces have the same overall length and overall width and have corner radii that are 30% of the width. 112. The blade unit of claim 5, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 113. The blade unit of claim 6, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 114. The blade unit of claim 7, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 115. The blade unit of claim 8, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 116. The blade unit of claim 9, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 117. The blade unit of claim 10, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 118. The blade device of claim 11 , wherein at least one of the front and rear edges of the blade device includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 119. The blade unit of claim 12, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 120. The blade unit of claim 13, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 121. The blade unit of claim 14, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 122. The blade unit of claim 15, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 123. The blade device of claim 17, wherein at least one of the front and rear edges of the blade device includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 124. The blade device of claim 18, wherein at least one of the front and rear edges of the blade device includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 125. The blade unit of claim 19, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 126. The blade unit of claim 20, wherein at least one of the front and rear edges of the blade unit includes a straight line portion and smoothly curved corner portions, the straight line portion along a major portion of the blade length part extending parallel thereto, the corner parts being located at one of the ends of the straight part. 127. The blade device of claim 5, wherein the skin-contacting surface has an oval shape. 128. The blade device of claim 6, wherein the skin-contacting surface has an oval shape. 129. The blade device of claim 7, wherein the skin-contacting surface has an oval shape. 130. The blade device of claim 8, wherein the skin-contacting surface has an oval shape. 131. The blade device of claim 9, wherein the skin-contacting surface has an oval shape. 132. The blade device of claim 10, wherein the skin-contacting surface has an oval shape. 133. The blade device of claim 11, wherein the skin-contacting surface has an oval shape. 134. The blade device of claim 12, wherein the skin-contacting surface has an oval shape. 135. The blade device of claim 13, wherein the skin-contacting surface has an oval shape. 136. The blade device of claim 14, wherein the skin-contacting surface has an oval shape. 137. The blade device of claim 15, wherein the skin-contacting surface has an oval shape. 138. The blade device of claim 17, wherein the skin-contacting surface has an oval shape. 139. The blade device of claim 18, wherein the skin-contacting surface has an oval shape. 140. The blade device of claim 19, wherein the skin-contacting surface has an oval shape. 141. The blade device of claim 20, wherein the skin-contacting surface has an oval shape. 142. The blade unit of claim 5, wherein the guard and cover surfaces are formed by resilient members. 143. The blade unit of claim 6, wherein the guard and cover surfaces are formed by resilient members. 144. The blade unit of claim 7, wherein the guard and cover surfaces are formed by resilient members. 145. The blade unit of claim 8, wherein the guard and cover surfaces are formed by resilient members. 146. The blade unit of claim 9, wherein the guard and cover surfaces are formed by resilient members. 147. The blade unit of claim 10, wherein the guard and cover surfaces are formed by resilient members. 148. The blade unit of claim 11, wherein the guard and cover surfaces are formed by resilient members. 149. The blade unit of claim 12, wherein the guard and cover surfaces are formed by resilient members. 150. The blade unit of claim 13, wherein the guard and cover surfaces are formed by resilient members. 151. The blade unit of claim 14, wherein the guard and cover surfaces are formed by resilient members. 152. The blade unit of claim 15, wherein the guard and cover surfaces are formed by resilient members. 153. The blade unit of claim 17, wherein the guard and cover surfaces are formed by resilient members. 154. The blade unit of claim 18, wherein the guard and cover surfaces are formed by resilient members. 155. The blade unit of claim 19, wherein the guard and cover surfaces are formed by resilient members. 156. The blade unit of claim 20, wherein the guard and cover surfaces are formed by resilient members. 157. The blade unit of claim 21, wherein the guard and cover surfaces are formed by resilient members. 158. The blade unit of claim 22, wherein the guard and cover surfaces are formed by resilient members. 159. The blade unit of claim 23, wherein the guard and cover surfaces are formed by resilient members. 160. The blade unit of claim 24, wherein the guard and cover surfaces are formed by resilient members. 161. The blade unit of claim 5, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 162. The blade unit of claim 6, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 163. The blade unit of claim 7, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 164. The blade unit of claim 8, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 165. The blade unit of claim 9, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 166. The blade unit of claim 10, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 167. The blade unit of claim 11, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 168. The blade unit of claim 12, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 169. The blade unit of claim 13, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 170. The blade unit of claim 14, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 171. The blade unit of claim 15, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 172. The blade unit of claim 17, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 173. The blade unit of claim 18, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 174. The blade unit of claim 19, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 175. The blade unit of claim 20, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 176. The blade unit of claim 21, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 177. The blade unit of claim 22, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 178. The blade unit of claim 23, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 179. The blade unit of claim 24, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 180. The blade unit of claim 25, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder. 181. The blade unit of claim 26, wherein at least two blades have forwardly directed edges, the two blades being mounted in the blade holder.

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