Patent Application
20130276588
This invention relates to cutting members for shaving razors.
Razor blades are typically formed of a suitable metallic sheet material such as stainless steel, which is slit to a desired width and heat-treated to harden the metal. The hardening operation utilizes a high temperature furnace, where the metal may be exposed to temperatures greater than 1145° C. for up to 18 seconds, followed by quenching.
After hardening, a cutting edge is formed on the blade. The cutting edge typically has a wedge-shaped configuration with an ultimate tip having a radius less than about 1000 angstroms, e.g., about 200-300 angstroms.
The razor blades are generally mounted on bent metal supports and attached to a shaving razor (e.g., a cartridge for a shaving razor).
In some aspects, the invention features a cutting member for a shaving razor, the cutting member including an elongated blade portion that tapers to a cutting edge; an elongated base portion that is integral with the blade portion; and a bent portion, intermediate the blade portion and the base portion.
In one such aspect, at least part of the cutting member has a thickness of at least about 0.005 inch (0.127 millimeter).
In another such aspect, the cutting member is formed of a material about 0.35 to about 0.43 percent carbon, about 0.90 to about 1.35 percent molybdenum, about 0.40 to about 0.90 percent manganese, about 13 to about 14 percent chromium, no more than about 0.030 percent phosphorus, about 0.20 to about 0.55 percent silicon, and no more than about 0.025 percent sulfur.
In yet another of these aspects, at least part of the cutting member has a ductility of at least about seven percent elongation.
Some embodiments include one or more of the following features. The cutting member may have an average thickness of about 0.005 inch (0.127 millimeter) to about 0.01 inch (0.254 millimeter); in some cases substantially the entire elongated blade, except for the cutting edge, has a thickness in this range. The bent portion may have an average thickness that is at least about 5 percent less than an average thickness of the base portion. The elongated base portion may be configured to be secured to the shaving razor. The elongated blade portion may extend at an angle of about 108 degrees to about 115 degrees relative to the elongated base portion.
The invention also features a cutting member for a shaving razor, the cutting member including a first portion; a second portion; and a bent portion intermediate the first and second portions, the bent portion having a thickness that is at least about five percent less than an average thickness of the cutting member.
The invention also features methods of making cutting members and razors including such members.
In one aspect, the invention features a method including deforming a continuous strip of material, and then separating the continuous strip into multiple discrete blades, each blade having a first portion, a second portion, and a bent portion intermediate the first and second portions.
Some embodiments may include one or more of the following features. Deforming the continuous strip of material may include pressing the strip of material between a punch and a die. Separating the continuous strip may include stamping or punching the strip. The method may also include punching longitudinally spaced apart slots in the strip prior to deforming the strip, the slots at least partially separating regions of the strip corresponding to the blades.
In another aspect, the invention features a method including hardening a strip of blade steel; forming a cutting edge on the hardened strip; after forming the cutting edge, bending the strip along its length by coining the strip; and separating the bent strip into individual blades, each blade having a bent portion.
Some embodiments may include one or more of the following features. The strip may be bent using a forming die that is configured so as not to touch the cutting edge. Bending the strip may reduce the thickness of the blade steel in the bent portion by at least about five percent relative to an original thickness of the blade steel.
The invention also features razors and razor cartridges including the cutting members described herein.
Embodiments can include one or more of the following advantages.
In some embodiments, the cutting member can be affixed to a cartridge of the shaving razor without the use of bent supports. Consequently, the shaving razor can include fewer components and, therefore, can be more cost-efficient than many conventional shaving razors.
In certain embodiments, the cutting member has a thickness that provides sufficient rigidity to prevent substantial deformation of the cutting member during use of the shaving razor.
In some embodiments, the cutting member is formed of a blade steel that has a hardness sufficient for forming a cutting edge that can cut hair, and has a ductility that is sufficient to allow bending of the blade without fracture or other substantial defects.
In some embodiments, the cutting members can be formed using a substantially continuous manufacturing process.
Other features and advantages of the invention can be found in the description, the drawings, and the claims.
Referring to
As shown in
Cutting members 100 can be mounted within cartridge 214 without the use of additional supports (e.g., without the use of bent metal supports like the one shown in
Referring again to
In certain embodiments, cutting member 100 is relatively thick, as compared to many conventional razor blades. Cutting member 100, for example, can have an average thickness of at least about 0.003 inch (0.076 millimeter), e.g., about 0.005 inch (0.127 millimeter) to about 0.01 inch (0.254 millimeter). As a result of its relatively thick structure, cutting member 100 can provide increased rigidity, which can improve the comfort of the user and/or the cutting performance of cutting member 100 during use. In some embodiments, cutting member 100 has a substantially constant thickness. For example, blade portion 105 (except for cutting edge 120), base portion 110, and bent portion 115 can have substantially the same thickness.
In some embodiments, the thickness of bent portion 115 is less than the thickness of blade portion 105 and/or base portion 110. For example, the thickness of bent portion 115 can be less than the thickness of blade portion 105 and/or base portion 110 by at least about five percent (e.g., about five percent to about 30 percent, about ten percent to about 20 percent).
In certain embodiments, cutting member 100 (e.g., base portion 110 of cutting member 100) has a hardness of about 540 HV to about 750 HV (e.g., about 540 HV to about 620 HV). Bent portion 115 can, for example, have a hardness of about 540 HV to about 620 HV. The hardness of cutting member 100 can be measured by ASTM E92-82—Standard Test Method for Vickers Hardness of Metallic Materials.
In some embodiments, cutting member 100 (e.g., bent portion 115 of cutting member 100) has a ductility of about seven percent to about 12 percent (e.g., about nine percent to about ten percent) elongation measured in uniaxial tension at fracture. The ductility of bent portion 115 can be measured, for example, by ASTM E345-93—Standard Test Methods of Tension Testing of Metallic Foil.
In some embodiments, bent portion 115 and the remainder of cutting member 100 have substantially the same ductility.
Cutting member 100 can be formed of any of various suitable materials. In certain embodiments, cutting member 100 is formed of a material having a composition comprised of about 0.35 to about 0.43 percent carbon, about 0.90 to about 1.35 percent molybdenum, about 0.40 to about 0.90 percent manganese, about 13 to about 14 percent chromium, no more than about 0.030 percent phosphorus, about 0.20 to about 0.55 percent silicon, and no more than about 0.025 percent sulfur. Cutting member 100 can, for example, be formed of a stainless steel having a carbon content of about 0.4 percent by weight, a chromium content of about 13 percent by weight, a molybdenum content of about 1.25 percent by weight, and amounts of manganese, chromium, phosphorus, silicon and sulfur within the above ranges.
In some embodiments, blade portion 105 and/or base portion 110 have minimal levels of bow and sweep. Bow is a term used to describe an arching normal to the plane in which the portion of the cutting member is intended to lie. Sweep, also commonly referred to as camber, is a term used to describe an arching within the plane in which the portion of the cutting member lies (e.g., an arching of the longitudinal edges of the portion of the cutting member). In some embodiments, blade portion 105 has a bow of about +0.0004 to about −0.002 inch (+0.01 to −0.05 millimeter) or less across the length of the blade portion. In certain embodiments, blade portion 105 has a sweep of about ±0.0027 inch (±0.07 millimeter) or less across the length of the blade portion. Base portion 110 can have a bow of about ±0.0024 inch (±0.060 millimeter) or less across the length of the base portion. By reducing the levels of bow and/or sweep in blade portion 105 and/or base portion 110, the comfort of the user and/or the cutting performance of cutting member 100 can be improved.
Sharpening device 315 can be any device capable of sharpening the edge of strip 350. Examples of razor blade cutting edge structures and processes of manufacture are described in U.S. Pat. Nos. 5,295,305; 5,232,568; 4,933,058; 5,032,243; 5,497,550; 5,940,975; 5,669,144; EP 0591334; and PCT 92/03330, which are hereby incorporated by reference.
Cutting device 320 can be any of various devices capable of providing slots 355 and/or slits 357 in strip 350. In some embodiments, cutting device is a punch press. In such embodiments, the progression of strip 350 can be periodically paused in order to allow the punch press to stamp slots 355 and/or slits 357 in strip 350. Cutting device 320 can alternatively or additionally be any of various other devices, such as a high power laser or a scoring operation followed by a bending or fracturing operation.
Referring again to
Bending device 330 can be any device capable of forming a longitudinal bend in strip 350. In some embodiments, as shown in
To form bent region 360 of strip 350, the relatively planar strip 350 is positioned between punch 365 and die 370, as shown in
As a result of the bending process, the thickness of strip 350 in bent region 360 can be reduced, relative to the thickness of strip 350 prior to being bent, by at least about five percent (e.g., about five percent to about 30 percent). Strip 350 in bent region 360, for example, can have a thickness of about 0.0035 inch (0.089 millimeter) to about 0.0095 inch (0.241 millimeter), while the remainder of strip 350 can have a thickness of about 0.005 inch (0.127 millimeter) to about 0.01 inch (0.254 millimeter).
Separating device 335 can be any device capable of separating the regions of strip 350 between slots 355 from the remainder of strip 350 to form discrete cutting members 100. In some embodiments, separating device 335 is a punch press. The progression of strip 350 can be periodically paused to allow the punch press to accurately separate the regions of strip 350 between slots 355 from the remainder of strip 350 to form cutting members 100.
Other devices capable of separating the regions of strip 350 between slots 355 from the remainder of strip 350 can alternatively or additionally be used. Examples of such devices include a high power laser or a scoring operation followed by a bending or fracturing operation.
While certain embodiments have been described, other embodiments are possible.
As an example, the order of many of the process steps discussed above can be altered. The process steps can be ordered in any of various different combinations.
Other embodiments are within the scope of the claims.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”
Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims propriety or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modification that are within the scope of this invention.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11400989 | Apr 2006 | US |
| Child | 13917721 | US |
