Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26B—HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR
  • B26B21/00—Razors of the open or knife type; Safety razors or other shaving implements of the planing type; Hair-trimming devices involving a razor-blade; Equipment therefor
  • B26B21/54—Razor-blades
  • B26B21/56—Razor-blades characterised by the shape

Definitions

• RAZOR BLADES Razor blades with undulating blade edges have been proposed, for example in U.S. Patents 2043998, 3654701 and 3797110, primarily for the purpose of pro- viding discrete edge portions which are set obliquely to the intended direction of travel of the razor over the skin in order to secure localized slicing cuts on facial hair.
• the blades shown in the first two U.S. Patents mentioned above are of the wafer type, that is they are formed from flat, stainless steel strip of minimal thick ⁇ ness which by analogy with conventional wafer blades as currently marketed would be in the order of 0.004" (0.1mm) .
• the sharpened edges must be cropped or otherwise given their basic undulating form and then sharpened by grinding facets which follow the undulating profile.
• the blades have rolled or forged guard ribs extending transversely to the edge and in one case the blade material between the ribs is impressed to a V-shape in one surface, so that when the blade edge is sharpened with a planar facet, the individual edge portions between adjacent pairs of ribs also have a V-shape.
• the amplitude of the V-shape is severely restricted by the fact that the depth of the impressed V-shape must be substantially less than the thickness of the blade material, Additionally, the width of the facet is not uniform but increases proportionately with distance from the apex of the 'V.
• the present invention aims at overcoming the shortcomings of the above mentioned blade edge designs.
• a razor blade formed from a wafer of blade steel to have at least one longitudinal edge and a series of corrugations each extending transversely to the length of said edge, and a substantially planar facet intersecting the said series of corrugations over the full depth there ⁇ of to define an undulating sharpened cutting edge.
• the width of the edge facet is substantially constant, provided that the thickness of the blade material is substantially constant through the corrugations.
• the amplitude of the corrugations is greater than the thickness of the blade strip so as to provide for blade edge undulations, measured in the plane of the facet, of substantial amplitude.
• deeper corrugations impart a greater degree of rigidity to the blade margin.
• the method of the present invention essentially comprises the steps of forming the corrugations in a planar strip of blade material, then hardening the strip and then cutting the facet, for example by grinding. Subsequent de-burring and polishing of the cutting edge may then be effected conventionally e.g. by electro-polishing.
• Figure 1 is a scrap perspective view of a blade edge formed in accordance with the invention
• Figure 2 is a plan view of the blade edge shown in Figure 1;
• Figure 3 is a section on the line III-III of Figure 2;
• Figure 4 is an end view of the blade edge form of Figures 1 to 3;
• Figures 5 and 6 are scrap perspective views of two razor heads incorporating the blades of Figures 1 to 4.
• the blade edge shown in the drawing is produced by forming a series of corrugations 10 in the marginal portion of a planar blade strip 11, which may be of a conventional blade steel of standard 0.1 mm thickness.
• the corrugations extend perpendicular to the edge of the strip and preferably extend equally to opposite sides of the original plane of the blade strip 11. (See le t hand portion of Figure 1) .
• the blade strip is then hardened and then ground by a conventional grinding wheel to form a facet 12 as shown in the right hand portion of Figure 1.
• the facet may be perfectly plane, or it may be formed by the periphery of a grinding.wheel, in which case it will be slightly concave, although for practical purposes it may be regarded as substantially planar.
• the facet intersects the series of corrugations over the full depth thereof, so as to define an undulating sharpened cutting edge which is co-planar with the facet 2 but which follows the contours of the corrugations.
• the edge may be finished by conventional means, for example by electro-polishing, to remove grinding burrs and to polish the facet 12.
• electro-polishing In grinding the facet, it is presently preferred to grind away from the edge, i.e. with the periphery of the grinding wheel passing downwardly along the facet 12 as viewed in Figure 4. This technique has less tendency to damage the sharpened edge. It results in a feathery burr, but this is found to be readily removed by electro- polishing.
• a wide variety of edge shapes may be derived by variations in the corrugations, particularly with reference to their pitch, amplitude and form.
• the amplitude ('A' in Figure 3) may, for example be 0.15, 0.25 or 0.38 mm and their pitch ('P 1 in Figure 2) may typically be from 0.5 mm to about 2 mm.
• the width of the corrugated marginal portion of the blade is about 2 mm, leaving the remainder of the blade strip plain. It would be alternatively possible if desired to currugate the blade strip across its full width and, if desired, to sharpen both edges. Again, the strip may be corrugated and sharpened at both edges, leaving a planar medial portion to the blade.
• the corrugations may conveniently be formed by a conventional press-tool, and the same tool may be employed to produce corrugations of different amplitudes by varying the degree of closure of the die and punch.
• corrugations shown are of generally sinusoidal form but they might alternatively be more angular, e.g. of generally V-shape. Furthermore, the corrugations are shown as extending perpendicular to the length of the blade strip but they could alternatively extend obliquely to the length of the strip.
• the blade edge included angle C'S' in Figure 4) may be in the range 15° to 30° and preferably between 18 ⁇ and 25°.
• the angle 'S' illustrated is 22 ° .
• Cutting edges of the above described form may be provided on both edges of a double-edge blade or as the sharpened edges of single edged blades of individual or of continuous strip form.
• Blades in accordance with the invention may be employed in various forms of safety razor but in most cases it is preferred to arrange the razor head and blade in such a way that the blade edge is presented to the skin with the blade facet substantially flat against the skin so as to reduce the risk of the leading tips of the un- dulating edge digging in to the ski , as well as to main ⁇ tain the full length of the edge in contact with the skin so as to optimise the cutting efficiency of the blade.
• One form of razor head incorporating a blade as described above, and which may be part of a disposable razor or may constitute an exchangeable cartridge is illustrated by way of example in Figure 5, which shows the blade securely and permanently clamped between a blade platform 20 and a cap member 21, with the corrugations projecting forwardly towards a guard member 22.
• the guard member 22 is formed on its rear, inner surface with corrugations 10 complementary to the un ⁇ dulating blade edge, so as to maintain a substantially con ⁇ stant gap or span between confronting portions of the guard member and blade edge.
• the blade is positioned relative to the guard and cap members with the blade edge facet 12 coincident or parallel with a notional plane drawn tangentially to the skin engaging surfaces of those members.
• the blade edge may be given a positive or a negative blade exposure measured as the perpendicular distance between the facet and the tangent plane, or it may have a zero exposure by positioning the facet in the tangent plane.
• Figure 6 is a scrap cross-section of a tandem blade cartridge or razor incorporating the blades of the present invention.
• the two blades are clamped between a blade plat ⁇ form 20 and cap member 21, with a spacer 23 sandwiched between the blades, and again the guard member 22 has a complementary undulating form.
• the blade facet angles S are both 22 ⁇ and both facets are set at a dis ⁇ tance ('E') of 0.5 mm above the notional guard/cap tangent plane.
• the undulations on both blade edges and the guard member are in register with each other.

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• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Dry Shavers And Clippers (AREA)
• Knives (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10553754

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (2)

Citations (6)

Family Cites Families (5)

• 1983
  • 1983-12-23 GB GB838334310A patent/GB8334310D0/en active Pending
• 1984
  • 1984-12-18 JP JP50021485A patent/JPS61500773A/ja active Pending
  • 1984-12-18 WO PCT/US1984/002092 patent/WO1985002809A1/en not_active Application Discontinuation
  • 1984-12-18 EP EP19850900437 patent/EP0167571A1/en not_active Withdrawn
  • 1984-12-18 GB GB08431917A patent/GB2151532A/en not_active Withdrawn
  • 1984-12-18 BR BR8407242A patent/BR8407242A/pt unknown
  • 1984-12-21 ES ES1984289841U patent/ES289841Y/es not_active Expired
• 1985
  • 1985-08-30 ES ES546592A patent/ES8608980A1/es not_active Expired

Patent Citations (6)

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