US3079689A - Pre-stressed razor blades, methods of production thereof, and holders therefor - Google Patents

Description

March 5, 1963 R. w. PECK 3, FRI-EI-STRESSED RAZOR BLADES, METHODS OF PRODUCTION THEREOF, AND HOLDERS THEREFOR Filed May 9. 1960 2 Sheets-Sheet 1 INVENTOR';

ATToRNEzi March 5, 1963 R. w. PEcK 3,079,689

PRE-STRESSEID RAZOR BLADES, METHODS OF PRODUCTION AND HOLDERS THEREFOR 2 Sheets-Sheet 2 THEREOF Filed May 9, 1960 7a. army ATTORNEYS linden aliases hastens BLADES, lflTHfiDS 8F Pi ZiJDUQTEGN TEEREGF, AND EfiLDERS Roger Wells Peel-I, 945 Fairrnount Ave., Towson, Md. Filed May 196%, Ser. No. 27,540 2 (Cl. 3tl346) This invention relates to certain improvements in prestressed razor blades, and the nature and objects of the invention will be readily recognized and understood by those skilled in the arts to which the invention relates in the light of the following explanation and detailed description of the accompanying drawings illustrating what i at present believe to be preferred embodiments or mechanical expressions of my invention from among various other forms, embodiments, combinations, constructions and expressions of which the invention is capabie within the broad spirit and scope thereof as defined by the claims hereto appended.

My invention is primarily concerned with overcoming certain disadvantages and eliminating the unsatisfactory shaving results therefrom encountered with safety razor blades of the flexible, thin metal types which are adapted for use in holders wherein they are removably clamped for support and operative positioning for shavin operations therewith. Generally, these thin, flexible types of razor blades are doubleedged, that is, the opposite parallel longitudinal edge portions of the blade are ground and honed to form the cutting edges and such blades are usually formed with a longitudinally extended central cutout, slot or aperture for receiving therein positioning members of the blade holder. While such thin, flexible razor blades are generally double edged, they may be provided with but a single cuttin edge with the blade body either solid without apertures or cut-outs or with such cut-outs, and attention is here directed to the fact that my present invention is not limited to blades of the double edge type but is equally applicable to blades of the single cutting edge ty es.

One of the major disadvantages of such thin, flexible types of metal razor blades resides in the dil'hculty in obtaining a cutting edge or cutting edges that will approach and hold as closely as practially possible to a theoretically straight edge. The cutting edges of such razor blades as now generally produced and marketed are found to have minute waves or irregularities in the form of minute departures or displacements of portions of the blade edge along its length laterally from the theoretical straight edge, even when the blade is mounted and clamped in operative shaving position in its holder. Uneven cutting results from such deviations of a blade edge from the theoretical straight edge and they are the frequent cause of small cuts and nicks in the skin as well as the uncomfortable pulling experienced during the shaving operation even with a new and unused or with a resharpe -ed blade cutting edge.

A main object of my invention is to provide a razor blade in which such disadvantageous cutting edge condi tic-us are substantially reduced by stretching and tensioning the blade cutting edge or edges in a manner to more closely approach and provide the theoretically straight cutting edge for obtaining a smoother yet closer and sharper cutting or shaving action.

A further object is to provide a razor blade having the above characteristics which can be produced in a simple, relatively inexpensive manner without external structural change in or addition to the blade and solely by permanent change in the internal structure of the metal making up the blade throughout certain areas of the blades relative to the cutting edge or edges.

A further object is to obtain the necessary tautness or tensicning in the blade edge to force and hold it permanently in a condition such that when the blade is clamped in operative position in the holder, the blade edge will more truly approach the theoretical straight edge than is possible with the edges of razor blades of the thin, flexible types as now being currently produced and used.

Another object is to provide a razor blade of the thin, flexible metal type in which the metal of the blade along and parallel with the cutting edge thereof is stretched or prestressed to place the edge in tension by changing the internal structure and distribution of the metal of the blade and thereby fixing the blade edge in straighter condition.

A further object is to provide a razor blade of the thin metal, flexible type in which the blade cutting edge is tensioned by redistributing metal internally in the blade to, in effect, shorten the length of the blade edge with respect to the length of the body of the blade and permanently set up a new pattern of internal stresses therein to bring the blade edge closer to the theoretically truly straight edge.

Another object is to provide a blade in which such redistribution of metal internally is accomplished by applying pressures to specific areas of the body of the blade.

Another object of the invention is to provide a method of redistributing metal internally of the blade to place a cutting edge of the blade under tension by the step of rolling certain areas of the blade body under pressure along and parallel to an edge of the blade to effect a controlled redistribution and change in the internal structure of the metal of the blade. 3

And a further object of the invention is to provide a. blade holder for a blade of the invention having such tensioned cutting edge in which the body of the blade is stretched by the holder when the blade is in operative clamped position therein in order to further longitudinally tension a cutting edge of the blade to force it to more nearly conform to the theoretical straight edge with a minimum of displacement of the cutting edge from the theoretical straight edge.

With the foregoing and various other objects, features and results in Vi w, which will be readily apparent from the following detailed description and explanation, my invention consists in certain novel features in a metal razor blade of the thin, flexible type and in a holder for such blade, all as will be more fully referred to and specified hereinafter.

Referring to the accompanying darwings in which similar reference characters refer to corresponding parts throughout the several figures thereof}:

FIG. 1 is a view in plan of a razor blade having prestressed areas of the body of the blade to place the blade cutting edges under tension in accordance with my invention.

FIG. 2 is a top view of a blade holder of my invention for positioning and clamping and further stretching a pre stressed blade of the invention as disclosed in FIG. 1, the holder being shown open with the blade of the invention positioned therein.

FIG. 3 is a vertical section through the blade and holder of PEG. 2, talsen as on the line 3-3 of FIG. 2.

FIG. 4 is a perspective View of a blade clamping and stretchin component of my invention for a different type of blade holder.

FIG. 5 is a perspective view of a blade clamping and stretching component of my invention for another type of blade holder.

FIG. 6 is a more or less schematic view in front elevationof an arrangement of pressure rollers for applying generally ground and finish dovaesa pressures alongropposite sides of blades passed therebetween to form the pre-stressed blades of my invention.

FIG. 7 is a more or less schematic view in side elevation of the 'pre-stressing roller arrangement of FIG. 6 in position relative to blade edge grinding and honing components of a blade production assembly.

A razor blade generally identified by the reference characters B, of the thin, flexible type formed of hardened and tempered steel and pro-stressed in accordance with my invention, isillustrated in FIG. 1 of the accompanying drawings. This blade B of the selected example hereof happens to be of a well-known and universally used shape and form of blade oi the double edged type having the opposite longitudinal and parallel cutting edges E ground and honed thereon along opposite longitudinal edges thereof. The blade body is provided with a cut-out in the form of a slot or elongated aperture C therein positioned along the longitudinal axis of the blade between the opposite ends of vthe blade with the latter providing the edges D at and defining the opposite ends vof the slot or aperture. This cut-out or slot C is provided for receiving the positioning and holdingcomponent or components of a blade holder in which the blade is to be mounted, as

willbe hereinafter explained in detail in connection with the blade holders of the invention exemplified in FIGS. 2, 3 and 4 of the accompanying drawings.

The blade B of the instant example of my invention maybe considered to have been formed of a steel composition having the following analysis, namely:

Carbon 1.25 to 1.30 Silicon 0.015 to 0.025 Manganese 0.030 Chromium 0.015 Vanadium 0.020 Phosphorous 0.025 Sulphur 0.015

While a steel of the above analysis is specifically here givenas'an example, it is to be understood that the invention is not limited to the use of a steel of such analysis but may be applied to and carried out with blades of any suitable steel composition of ananalysis capable of being hardened and then tempered by suitable heat treatments, and'adapted to the production of pre-stressed razor blades in accordance with my present invention.

Razor blades of the illustrated example of the invention may be'considered to be manufactured in accordance with prevailing methods of razor blade manufacture by which thesteel is in strip form, such as the strip S schematically shown in FIGS. 6 and 7. Such a strip S is progressively punched or shaped to form a series of connected blade blanks which are then hardened and temperedwith the cutting edges thereon progressively rough ground and finally honed to complete Usually after honing the individual blades of a strip thereof are then cut or otherwise separated from the strip and packed for the market. In the instant example the blades so formed may have a finished thickness of the order of .0060", although it is here pointed out that blade thickness is not necessarily critical as. a blade may be formed in accordance with my invention of a thickness more or less than the selected example thickness of .0060". In accordance with my invention the step of hardening the steel of the above analysis is carried to give the steel a hardness of the order of Rockwell 60-61 C scale, before the step of pre-stressing is performed thereon. I

Itis found that the thin, flexible types of razor blades as now'being produced under quantity production conditions inherently have generally unsatisfactory cutting edge conditions'in that the cutting edges thereof after grinding and honing are'minutely and irregularly wavy'or depart in minute sections therealong laterally in either direction from the theoretical straight cutting edge; The foregoing cuttingedge conditions are' notsubstantially alleviated or edge condition.

reduced when such a blade is clamped and positioned in a holder for shaving therewith. It is believed that in some instances such unsatisfactory cutting edge conditions arise.

cutting edge or edges of the blades will not'thereby be placed in the necessary longitudinally stressed or tensioned condition to draw and stretch the cutting edge or edges to reduce departures thereof from the theoretical straight edge. Thus, in shaving with a razor blade having such a cutting edge, uneven cutting may result with the hazard of small nicks and cutsinthe skin as well as the disagreeable pulling of the beard encountered during shaving.

These unsatisfactory blade edge conditions that are encountered with the currently available razor blades when such a blade is clamped in a holder in operative position for shaving cari be eliminated or substantially reduced if, in accordance with my invention, a blade is so treated and conditioned that the cutting edge of edges thereof are initially pre-stres'sed and placed and permanently maintained under a substantial degree oftension or stretching so that the blade edges more closely approach theoretical straight edges; Such a blade of my invention, if of one of the known conventional forms andshapes of blades, such as the blade B of the 'examp'le illustrated herein, may then be clamped in the holder for which it is designed and will function therein for smoother and more satisfac tory shaving resultsl v However, in accordance with a further feature of my invention I have provided several forms of blade clamping and stretching components'for incorporation invarious types of holders which will further longitudinally stretch and tension the blade cutting edges when a blade of my invention is op'eratively positioned and clamped in such a holder. Whether a blade of the invention is used in the customary holder designed for it, or'is clamped in a holder having the clamping and stretching component in accordance with my invention, much smoother and closer beard cutting will result and the hazard of skin nicks and cuts and the disagreeable pulling effect during shaving will be substantially reduced. In accordance with my invention, as applied to and incorporated in the double edged and centrally slotted, thin, flexible steel razor blade B of the selected example hereof, I stretch or elongate and pre-st ess the portions 1 and '2 of the blade body that lie along and between the central aperture or slot C and the opposite parallel longitudinal cutting edges E. This tensioning and pre-stressing is preferably done over a relatively narrow 'width of the blade body along the line a-b located parallel with the ad acent cutting edge E and between that edge and the central slot or aperture C, as indicated on FIG. 1 of the drawings. I prefer to do this tensioning and pre-stressing with the blade cold and after hardening and tempering, by applying rollers under pressure to and longitudinally along the lines ab of such portions 1 and 2, respectively, of the blade body, under sufficient pressure to reform the steel at the interior of such portions of the blade body and to thereby, in effect, redistribute portions thereof from along each ofthe edges E by taking material away from such edge'portions and rolling it into the portions 1 and 2 to thereby longitudinally elongate such latter portions to permanently tension and pro-stress the opposite cutting edges E and thereby'permanently stretch such edges into conditions more closely approaching the theoretical straight edges. However, if desired or found expedient, the entire area of the body B between theoppo'site' cutting edges B may be pre-stressed by rollers applied'to and completely in contact across such area under pressure to'thus draw material internally from the cutting edges E and the portions of the-body'B immediately adjacent thereto and redistribute such material ofthe blade intothe portions of the body cutting edges E to thus stretch such portions and place the cutting edges permanently under tension.

Such pro-stressing of portions of the body of the blade with resulting tcnsioning of the blade edges is preierably carried out with the blade cold and may performed at any time after the blade has been heat treated and hardened and tempered. Such prestressing is pref racly perfori 16d prior to the separation or cutting of the individual blades from the strip of blades, although it may be performed if found desirable to each individual blade after sepa ation thereof from the blade strip. By thus treating and reforming the internal structure of the blade, the body portions are, in sheet made longer than the cutting edges and together with the cutting edges are permanently prestressed so that the ed es are thereby tightly ter oned and stretched longitudinally to more nearly approach the theoretical straight edge.

A razor blade of the invention thus treated and pr stressed is preferably used in a holder such as one of the holders of the invention, as will be hereinafter describe When a blade is positioned and clamped in such a holder, further stretching forces are applied to the central portion of the body or the blade and thus place the pro-stressed and tensioned blade edges under greater tension so that they are further stretched into a condition very closely approaching theoretically straight cutting edges.

With the form of blade B of the example of a haoness of Rockwell 606l, as aforesaid, where the cutti V edge are pro-stressed and placed permanently under tensio by applying pressures to the body or" the blade along paths as defined by the lines ab of PK 1, I apply such prestressing pressures at opposite sides of the blade by suitable pressure rolls. in FIGS. 6 and 7 I have schematically illustrated an arrangement of rolls for applying p to a blade B in such a manner as to pro-stress the blade cutting edges E in accordance with the principles or" my invention. Such a pre-stressing roll arrangement may in clude an upper roll UR and a lower roll LR, each fo ed of hardened tool steel. The pre-stressing rolls UR and LR are identical with each other and each includes a body, shaft or spindle with ollers formed thereon coaxial therewith and spaced apart axially thereof. Each roll and the rollers formed thereon may be an integral unit in which rollers are formed on anti integral with the body, or the rollers may be separate components fixed to a shaft or spindle. The upper roll UR is comprised by the body or spindle 15 on which is fcrmec integral therewith the spaced rollers and 11, while the lower roll which is identical in this instance with the upeer roll, is com rised of the body or spindle J) on which is formed integral with t mere- .e spaced rollers 1 and E6. in this particular instance each of the rollers 11? and 11 of upper roll UR and id and to or" the lower roll LR is identical and each provides a relatively narrow, convexly curved rouneed peripheral, contacting edge for engagin applying ere-stressing pressure to a blade. The rollers it and 11 of upper roll UR and the rollers 14 and of the lower roll LR ar spaced apart axially along the body or sh their respective roll such that the centers of the oer-- contact surfaces 16 of the rollers will engage the body of a blade B along the lines a-b, respectively, at opoosite sides of the blade body. The rolls UR and Lil are mounted in position so that the rollers 14 and "1'6 of r ll apposite and in line with the rollers ill and ii, resusct vely, of the roll UR, so that the porticns of a blade along the lines a-b are engaged under pressure between p2- rs of rollers.

"the upper roll UR and the lower roll LR are each prc sure forced toward each other so as to force the nairs f rollers l9-ll and l4-ll into pressure engagement contact with opposite sides, respectively, of a blade B being moved therctirough and there tween. Any suitable force-exerting means may be r; force the rollers of the rolls UR and LR under p :ist and the opposite sides of a blade 23 in rolling contact with and to maintain such rolls under pressure during gassage f a blade there'oetween. in the particular example hereof I have schematically illustrated screw means P for loading the rolls UR and LR, that is, for anplying radially acting forces thereto to force the rollers of these rolls into engagement with a blade being fed or drawn therebetween. Attention is directed to the fact, however, that any other suitable type of loading, such as hydraulic, or even springs, may be utilized to force the rolls inwardly toward each other and maintain them with their respective rollers in rolling engagement under pressure with a blade or blade strip being moved therebetwee-..

The pro-stressing of the blade by the opposing pressureapplying rolls UR and LR is preferably done after the blades have been heat-treated and hardened and before the blades are ground and honed. For example, in FIG. 6 what I now believe to be a preferred location for such pre-stressing rolls is schematically illustrated with the rolls operatively positioned for pro-stressing the blades after the heat-treating t. ereof is completed and in advance of the grinding and honing of the blades. In such location the strip of lades S is drawn from the hardening and heattreating locations and is then fed or drawn between the pro-stressing rolls UR and LR and gore-stressed thereby, after which the strip of blades passes through the usual grinding and honing units, as schematically indicated in FIG. 6, such grinding and honing units or locations being generally identified by the reference characters G and H, respectively. When the blade strip S leaves the grinding and honing units G and H, the pre-stressed blades of my invention may then be separated from the strip for packing.

My invention contemplates and includes cutting edge pre-stressing and tensioning of a razor blade having but a single cutting edge. With a single cutting edge blade the pre-stressing and stretching of the blade body and edge longitudinally may be done along an area immediately adjacent the cutting edge, in the manner above described in connection with an edge E of the blade 8, and over a Width sufficient to obtain the necessary redistribution of material internally of the blade so as to longitudinally pre-stress the body and thus tension and stretch the cutting edge. liowever, if found desirable or expedient, ubstantially the entire width of the cutting b .de from adjacent the single cutting edge thereof to and adjacent the opposite, non-cutting edge, may be pressure rolled to obtain the desired pre-stressing and tensioning of the single blade edge.

While razor blades of my invention, such as blade 3 of the illustrated example, with their prestre sed and tensioned cutting edges E brought to condition closely approaching the theoretical straight edge, are highly ethcient and will obtain the desired new results when used in the conventional holders designed for them, nevertheless I have, in accordance with a further feature of my invention, provided a design of blade holding component of a known type of blade holder that will further longitudinally stress and tension a blade cutting edge when a blade is mounted and clamped in such a holder. in FIG. 2 of the drawings 1 have shown such a component of my invention as embodied in the center bar component of a welllrnown standard holder for a blade of the form and design of the blade B. it is believed only necessary herein to generally illustrate such well-known type of holder as such type is in Wide general use and the construction and operation thereof are known.

Such a blade holder includes a handle Ztl transversely across one end of which there is secured a head structure 21 which provides a blade receiving platform or base corn nonent. An actuating rod 22 extends axially through nanole and mounts at the end thereof at the head structure 21, the center bar 23. Rod 22 is engaged by a rotatable part of the handle 29 and may thus be axially displaced outwardly and inwardly to displace the center bar 23 outwardly or inwardly relative to the head 21, all as well known and familiar in this art. Suitable clamping plates 24 are positioned along the opposite outer longitudinal edges of the head 21 and are pivotally coupled with opposite end linkage systems indicated generally in each instance by the reference character 25 that are in turn operatively coupled and connected to opposite ends, respectively, of the center bar 23. A blade, such as the blade B of the selected example of the invention, is mounted in the holder when the clamping plates 24 are intheir outwardly swung positions, with'the center bar 23 received in and extending upwardly through the center slot or aperture C of the blade 13 as shown in FIG. 2. The center bar 23 provides the opposite end edge surfaces 26 which, in accordance with my invention, 1 dispose at an inclination inwardly from the outer edge 27 of the bar 23 to the head structure 21, so as to thereby present the surfaces 26 as wedging or camming surfaces for en gagernent by the opposite edges D provided by the blade body B at the opposite ends ofthe central slot C.

In the operation of the type of holder generallyillu'strated by FIG. 2 when the actuating rod 22 is moved outwardly, it carries with it the center bar 23 and through the linkages 25 swings the clamping plates to open posi tion and is itself bodily displaced outwardly from the head 21. When rod 22 is drawn inwardly relative to the head structure 21, the center bar 23 is drawn inwardly and through the linkages 25 swings the clamping plates 24 inwardly into blade clamping and setting position. Thus, when a pre-stressed blade B of the invention is mounted'in this type of holder, the center bar 23 is reccived in and extends'outwardly through the central slot C of the'bladewith the camming surfaces 250i the center bar out of camming engagement with the edges D of the blade when the holder is in its open, blade-receiving position of FIG. 2. However, when the clamping plates 24 are swung inwardly to blade clamping and setting positions, the center bar 23 is drawn inwardmly and thereby the camming surfaces 26 at the opposite ends of this bar engage the edges D, respectively, of the blade and longitudinally stretch the blade so that the already pretensioned and stressed cutting edges E of the blade are further drawn or stretched longitudinally to force them further toward the theoretical straight edge. In this manner increased shaving efficiency, including sharper and smoother beard cutting with the obtained potential inherent in the blade to cut or nick t e skin being substantially reduced. p

In FIG. 4 of the drawings the blade clamping plate 3i? for another type of holder for blades of the form of blade B is shown inreverse position, that is, with the underside thereof uppermost. A'longitudinal and centrally disposed rib member 31 is provided extending outwardly from the underside of clamping plate member 3% for fitting into a suitable central aperture or slot in a double edged blade, such as the slot C of blade B. The opposite ends of the rib member 31 are, in accordance with my invention, formed to provide the inclined wedging or camming surfaces 32 for camming engagement with the opposite end edges of the central slot of a blade, such as the edges D of the blade B. When the clamping plate 36 is in its normal position in the holder, it rests on the blade with the rib member 31 received in the central slot of the blade. Then, when the plate 36 is drawn inwardly to operative blade clamping position by suitable actuating means engaged with the post 33 in a manner well known in the art, the camrning edges 32 engage the edges D of the blade and further longitudinally stretch the blade to increase the longitudinal tensioniug and stretching of the cutting edges of the blade.

In another form of holder blade clamping plate 39' for a type of holder similar to that for which the plate member 30 of FIG. 4 is employed, instead of a continuous longitudinal rib member, the longitudinally spaced and centrally located lugs 32 are provided projecting outwardly from the underside of the plate 3W. Each lug member 32;"has the outer side thereof which is adjacent an end of the plate 313 inclined inwardly to provide a camming surface 32". With such form of blade clamping plate, a blade is either provided with a central slot or aperture having edges, such as the edges D of blade B, at opposite ends thereof for carnming engagement with the surfaces 32" of the lugs 32', or may be provided with spaced holes or apertures therethrough' positioned for receiving the lugs 32' for operation of the camming surfaces 32" when the clamping plate is drawn inwardly on its holder, to further longitudinally stretch a blade and thereby increase the tensioning of the blade cutting edge or edges.

It will also be evident that various other changes, modifications, constructions, combinations, substitutions and additions may be resorted to inthe' pro-stressed blades and in the method of producing such blades, without departing from the broad spirit ands'cope' of my invention, and hence I do not intend or desire to limit my invention in all respects to the exact and specific examples of blades and/or of method as herein disclosed, except as may be required by intended specific limitations thereto appearing in any of the claims hereto appended.

What I claim is:

1. A cutting blade comprising a tlrin, flexible blade body formed of heat-treated and hardened steel having an edge thereof providing a cutting edge; said heattreated and hardened blade body having the internal structure of a section thereof adjacent to, and substantially parallel with and extending throughout substwtially the length of said cutting edge permanently reformed and permanently longitudinally t'ensioned' and elongated relative to the length of said cutting edge; and said cutting edge being permanently drawn and tensioried longitudinally by said permanently reformed and elongated adjacent section of said straighter edge condition.

2. A cutting blade comprising a thin flexible blade 7 body formed of heat-treated and hardened steel having opposite parallel edges thereof providing cutting edge said blade body having an elongated slot therethrough along and centrally located between said opposite cutting edges; said heat-treated and hardened blade body structure having the internal structure of a section thereof adjacent to and substantially parallel with and'extending substantially throughout the length of each of said cutting edges between such cutting edge and said centrally located slot permanently reformed with such section permanently longitudinally tensioned and elongated relative to the length of said cutting edge adjacent thereto; and each of said cut-ting edges being permanently drawn and tensioned' longitudinally by said permanently internally reformed and elongated section of said blade body adjacent thereto into a permanent straighter edge condition.

References Cited in the til of this patent UNITED STATES PATENTS 1,734,554 Behrman 1,916,416 Connolly July 4, 1933 2,693,874 Stargardter Sept. 21, 1937 2,322,744 Benjamin June 29, 1943 2,365,581 Muros Dec. 19, 1944 2,593,307 Jacobseu Apr. 15, 1952 2,632,243 Hellmann Mar. 24, 1953 2,754,583 Liberatore July 17, 1956 2.952.911 Shuitzier et al. Sept. 20, 1960 blade body into permanent Nov. 5, i929

Claims (1)

1. A CUTTING BLADE COMPRISING A THIN, FLEXIBLE BLADE BODY FORMED OF HEAT-TREATED AND HARDENED STEEL HAVING AN EDGE THEREOF PROVIDING A CUTTING EDGE; SAID HEATTREATED AND HARDENED BLADE BODY HAVING THE INTERNAL STRUCTURE OF A SECTION THEREOF ADJACENT TO, AND SUBSTANTIALLY PARALLEL WITH AND EXTENDING THROUGHOUT SUBSTANTIALLY THE LENGTH OF SAID CUTTING EDGE PERMANENTLY REFORMED AND PERMANENTLY LONGITUDINALLY TENSIONED AND ELONGATED RELATIVE TO THE LENGTH OF SAID CUTTING EDGE; AND SAID CUTTING EDGE BEING PERMANENTLY DRAWN AND TENSIONED LONGITUDINALLY BY SAID PERMANENTLY REFORMED AND ELONGATED ADJACENT SECTION OF SAID BLADE BODY INTO PERMANENT STRAIGHTER EDGE CONDITION.

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