WO1984002104A1 - Lames de rasoir - Google Patents

Lames de rasoir Download PDF

Info

Publication number
WO1984002104A1
WO1984002104A1 PCT/GB1983/000288 GB8300288W WO8402104A1 WO 1984002104 A1 WO1984002104 A1 WO 1984002104A1 GB 8300288 W GB8300288 W GB 8300288W WO 8402104 A1 WO8402104 A1 WO 8402104A1
Authority
WO
WIPO (PCT)
Prior art keywords
tip
edge
blade
stainless steel
cross
Prior art date
Application number
PCT/GB1983/000288
Other languages
English (en)
Inventor
Francis Russell Curry
Edwin Lloyd Glasson
Joan Pumfrey
Romauld Kozlowski
Original Assignee
Glasson Edwin Lloyd Personal R
Kozlowska Jadwiga Personal Rep
Gillette Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=10534368&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO1984002104(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Glasson Edwin Lloyd Personal R, Kozlowska Jadwiga Personal Rep, Gillette Co filed Critical Glasson Edwin Lloyd Personal R
Priority to BR8307616A priority Critical patent/BR8307616A/pt
Priority to DE8383903805T priority patent/DE3372189D1/de
Publication of WO1984002104A1 publication Critical patent/WO1984002104A1/fr
Priority to US06/870,622 priority patent/US4720918A/en

Links

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
    • 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
    • B26B21/58—Razor-blades characterised by the material

Definitions

  • This invention relates to razor blades and is particularly concerned with the shaping of the cutting edge.
  • n is in the range 0.65 to 0.75 and a is in the range 0.70 - 0.80.
  • blades having these tip characteristics provide improved shaving on comparative shave testing, but are sufficiently strong to give a reasonable useful life.
  • Figure 1 is a greatly magnified view of a blade tip of typical, or average shape
  • Figure 2 is a tip shape diagram illustrating the principle of "chord-width” measurement
  • Figure 3 is a highly diagrammatic representation of the cutting of a facial hair
  • Figures 4 to 7 are cross-sections of various respective blades currently marketed by a variety of manufacturers;
  • Figure 8 is a view, like Figures 4 to 7, of the tip shapes described in British Patent Specification 1465697.
  • Cutting edges on razor blades are sharpened by grinding a succession of pairs of facets (usually three) of different included angles onto a strip of steel by means of suitably arranged abrasive wheels.
  • the cross-section through such an edge is illustrated in Figure 1 with typical values for dimensions and angles shown, and is customarily described as a "3-facet edge".
  • strip deflection in the sharpening machine together with the mechanical interaction between the steel and the abrasive particles of the wheel, produces final facets which are usually not planar but slightly convex.
  • the curvature is a function of the type of steel and abrasive wheel used, as well as the sharpening machine setting parameters.
  • the blade tip cross section in this region is customarily referred to as "Gothic arched".
  • the curvature prohibits precise geometrical definition of this part of the blade tip bymeans of a single parameter ao that it is usual to characterise the shape by defining "tip” or “chord” widths at various distances back from the edge.
  • An alternative method is to ascribe a mathematical equation to fit the form of each half of the facet cross-section. These methods are illustrated in Figure 2.
  • a razor blade is held in the razor at an angle of approximately 25o, and with the edge in contact with the skin, it is moved over the face so that when the edge encounters a beard hair, it enters and severs it by progressive penetration, aided by a wedging action. It is believed that the cut portion of the hair (which is on average about 100 ⁇ m diameter) remains pressed in contact with the blade facets remote from the facial skin surface for a penetration up to only about half the hair diameter. Beyond this, the hair can bend and contract away from the blade to relieve the wedging forces. The resistance to penetration through reaction between hair and blade facets therefore occurs only over about the first 50 ⁇ m of the blade tip back from the edge and the geometry of the blade tip in this region is regarded as being the most important from the cutting point of view. This is illustrated in Figure 3.
  • Blades currently produced have tip geometries with some dimensions which are below these minimum values and are known to become dulled by edge bending during the normal shaving life (which is on average, approximately 10 days for a blade made from conventional razor blade stainless steel).
  • the blade tip cross-section is first narrowed by grinding the three facets to smaller included angles than those typified in Figure 1. This produces a blade tip whose cross-section is generally narrower throughout and, importantly, in the 0 -40 ⁇ m distance back from the edge, which is of particular interest during hair cutting. Such an edge is too weak to withstand stresses during shaving and must be further modified. This is achieved by adding what amounts to a fourth sharpening stage. It is carried out using rotating interlocking discs or spirals of leather or synthetic leather, (usually called "strops”) with abrasive material added to their peripheries.
  • strops rotating interlocking discs or spirals of leather or synthetic leather
  • abrasive stropping Because of the flexibility of the strop leather, allowing it to conform somewhat to the sharpened blade tip, abrasive stropping increases the curvature of the final facet, close to the edge, while having less effect on the facet shape further back.
  • the ultimate tip radius of the edge should be conventional, with an average value of less than 1000°A and preferably less than 500°A as stated, for example, in Patent Specification 1,378,550 (U.S. 3,761,374), that is, within the normal range for conventionally sharpened edges.
  • Blades in accordance with the invention have been found to have superior shaving performance when compared with conventional blades on a standard shaving test.
  • One form of blade in accordance with the invention and the manner in which it is formed are described in detail below, by way of example, with reference to Figures 9, 10 and 11, in which: Figure 9 is a diagrammatic illustration of a blade tip stropping operation;
  • Figures 10 and 10A are representations of blade tip forms in accordance with the invention, compared with the known blade tip forms seen in Figures 4 to 8.
  • Fig. 10A is a detail from Fig. 10 on a larger scale;
  • Figure 11 is a graph of chord widths 'w' at different distances 'd' plotted on logarithmic scales.
  • Stainless steel razor blade strip of nominal composition 1 3% Cr , 0.6% C, was hardened and tempered in accordance with conventional practice, and sharpened by grinding and honing to produce edges of three facet configuration, as illustrated in Figure 1, but with included angles smaller than those conventionally manufactured.
  • the blades were passed between rotating strops of artificial leather, whose surfaces contained fine alumina abrasive, in the manner of conventional abrasive stropping, where the angle set on the strops (which is the included angle between the tangents to the strops at their point of intersection, as shown in Figure 9) was in the range 30°-34°.
  • the facets were provided with a metallic coating of an alloy of chromium and platinum (applied in accordance with Patent U.S.
  • the blade is tilted at an appropriate angle so that the fringes are displaced to reveal the topography of the blade facets.
  • the fringe spacing is adjusted so that fringe displacements can be readily measured at various distances back from the edge. Knowing the angle of tilt, the tip shape is calculated from the sum of these fringe displacements, measured at corresponding positions on each side of the blade.
  • chord widths w at distances d from the extreme edge were as set out below:- d ( ⁇ m) w ( ⁇ m)
  • the known blades measured were found to have best fit straight lines with exponents (or gradients) within the range 0.76 - 1.0.
  • the smaller gradient is a primary characteristic of the present invention and results in the fact that the blade tip of the present invention, compared with those of the prior art, is relatively thick and strongly arched close to the extreme edge, but relatively thin over the remainder of the tip.
  • the included facet angles in the region 40 - 100 ⁇ m from the tip are in the range 9o to 111 ⁇ 2o but making due allowance for manufacturing tolerances could be in the range 7o to 12o or even 7o to 14o.
  • tip shapes described above are for stainless steel blades and could be made substantially thinner for harder blade materials such as sapphire, titanium carbide or diamond.
  • chord widths In inverse proportion to the square root of the yield strength of the harder material in comparison with stainless steel, we reduce the corresponding chord widths in inverse proportion to the square root of the yield strength of the harder material in comparison with stainless steel. In the case of diamond, for example, the chord widths would be approximately 40% of those calculated for stainless steel.
  • the tip region of a stainless steel blade may be coated with a .material harder than stainless steel and having a higher yield strength.
  • the chord widths given by the basic equation are reduced by adopting the modified formula: in which m is the ratio of the yield strength of the coating material to that of stainless steel.
  • the value for w must also satisfy the equation W 3 ⁇ (W-2h)a 2 d 2n , where h is the thickness of the coating.
  • h is the thickness of the coating.

Landscapes

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

Abstract

Le fil d'une lame de rasoir possède une forme en coupe définie, sur 40 mum à partir du bord extrême, par l'équation w = adn, dans laquelle w est l'épaisseur de la corde du fil de la lame en mum à une distance d à partir du bord extrême; a est un facteur de proportionnalité n'excédant pas 0,8, et n est un exposant ayant une valeur comprise entre 0,65 et 0,75. On obtient un fil de lame dont la forme est relativement épaisse très près du bord mais dont la section globale est étroite, par rapport aux formes de fil connues.
PCT/GB1983/000288 1982-11-19 1983-11-14 Lames de rasoir WO1984002104A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BR8307616A BR8307616A (pt) 1982-11-19 1983-11-14 Laminas de barbear
DE8383903805T DE3372189D1 (en) 1982-11-19 1983-11-14 Razor blades
US06/870,622 US4720918A (en) 1982-11-19 1986-06-04 Razor blades

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8233014 1982-11-19

Publications (1)

Publication Number Publication Date
WO1984002104A1 true WO1984002104A1 (fr) 1984-06-07

Family

ID=10534368

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1983/000288 WO1984002104A1 (fr) 1982-11-19 1983-11-14 Lames de rasoir

Country Status (9)

Country Link
EP (1) EP0126128B1 (fr)
JP (1) JPS59502135A (fr)
CA (1) CA1229476A (fr)
DE (1) DE3372189D1 (fr)
ES (1) ES275817Y (fr)
GB (1) GB2130955B (fr)
IN (1) IN160884B (fr)
MX (1) MX161634A (fr)
WO (1) WO1984002104A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0884142A1 (fr) * 1997-06-10 1998-12-16 Warner-Lambert Company Arrête de lame améliorée
US6962000B2 (en) 2001-07-11 2005-11-08 Koninklijke Philips Electronics N.V. Cutting member with dual profile tip
EP3592515B1 (fr) 2017-03-08 2020-07-29 BIC-Violex S.A. Lame de rasoir
EP3592516B1 (fr) 2017-03-08 2020-10-07 BIC-Violex S.A. Lame de rasoir
EP3800016A1 (fr) * 2019-10-01 2021-04-07 Dorco Co., Ltd. Lame de rasage
WO2021256728A1 (fr) * 2020-06-16 2021-12-23 주식회사 도루코 Lame de rasoir
US11230025B2 (en) 2015-11-13 2022-01-25 The Gillette Company Llc Razor blade
US11654588B2 (en) 2016-08-15 2023-05-23 The Gillette Company Llc Razor blades

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7144403B2 (en) 2003-07-29 2006-12-05 Alcon, Inc. Surgical knife
JP4575735B2 (ja) * 2004-09-27 2010-11-04 フェザー安全剃刀株式会社 ミクロトーム替刃
US9751230B2 (en) * 2014-05-19 2017-09-05 The Gillette Company Razor blades
WO2016015771A1 (fr) 2014-07-31 2016-02-04 Bic-Violex Sa Revêtement de lame de rasoir
MX2017008324A (es) * 2014-12-22 2017-10-24 Bic Violex Sa Hoja de afeitar.
JP6864034B2 (ja) * 2019-05-13 2021-04-21 ビック・バイオレクス・エス・エー 剃刀の刃
US20210276211A1 (en) * 2020-03-05 2021-09-09 John Robert Harris Razor blade with improved asymmetric profile

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1258348A (fr) * 1969-10-15 1971-12-30
US3811189A (en) * 1971-07-09 1974-05-21 Gillette Co Process for producing an improved cutting tool
FR2234100A1 (fr) * 1973-06-20 1975-01-17 Wilkinson Sword Ltd

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3461616A (en) * 1966-10-14 1969-08-19 Gillette Co Methods and apparatus for sharpening razor blades or similar cutting tools
GB1350594A (en) * 1970-02-05 1974-04-18 Gillette Industries Ltd Sharpening cutting edges

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1258348A (fr) * 1969-10-15 1971-12-30
US3811189A (en) * 1971-07-09 1974-05-21 Gillette Co Process for producing an improved cutting tool
FR2234100A1 (fr) * 1973-06-20 1975-01-17 Wilkinson Sword Ltd

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0884142A1 (fr) * 1997-06-10 1998-12-16 Warner-Lambert Company Arrête de lame améliorée
AU738778B2 (en) * 1997-06-10 2001-09-27 Warner-Lambert Company Improved blade edge
US6962000B2 (en) 2001-07-11 2005-11-08 Koninklijke Philips Electronics N.V. Cutting member with dual profile tip
US11230025B2 (en) 2015-11-13 2022-01-25 The Gillette Company Llc Razor blade
US11654588B2 (en) 2016-08-15 2023-05-23 The Gillette Company Llc Razor blades
EP3592515B1 (fr) 2017-03-08 2020-07-29 BIC-Violex S.A. Lame de rasoir
EP3592516B1 (fr) 2017-03-08 2020-10-07 BIC-Violex S.A. Lame de rasoir
EP3800016A1 (fr) * 2019-10-01 2021-04-07 Dorco Co., Ltd. Lame de rasage
US11660770B2 (en) 2019-10-01 2023-05-30 Dorco Co., Ltd. Shaving blade
EP4219100A1 (fr) * 2019-10-01 2023-08-02 Dorco Co., Ltd. Lame de rasage
WO2021256728A1 (fr) * 2020-06-16 2021-12-23 주식회사 도루코 Lame de rasoir

Also Published As

Publication number Publication date
JPH0532076B2 (fr) 1993-05-14
ES275817Y (es) 1984-12-16
EP0126128B1 (fr) 1987-06-24
IN160884B (fr) 1987-08-15
CA1229476A (fr) 1987-11-24
GB2130955B (en) 1985-10-02
ES275817U (es) 1984-05-16
GB2130955A (en) 1984-06-13
GB8330432D0 (en) 1983-12-21
EP0126128A1 (fr) 1984-11-28
MX161634A (es) 1990-11-27
JPS59502135A (ja) 1984-12-27
DE3372189D1 (en) 1987-07-30

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