US3505734A - Cutting blade with self-contained guard - Google Patents

Description

April 14, 1970 c. A. ITEN 3,505,734

CUTTING BLADE WITH SELF-CONTAINED GUARD Filed Feb. 28, 196B 2 Sheets-Sheet 1 April 14, 1970 l c. A. lTr-:N

CUTTING BLADE WITH SELF-CONTAINED GUARD 2 Sheets-Sheet 2 Filed Feb. 28, 1968 United States Patent O 3,505,734 CUTTING BLADE WITH SELF-CONTAINED GUARD Clemens A. Iten, Staunton, Va., assignor to Philip Morris Incorporated, New York, N.Y., a corporation of Virginia Filed Feb. 28, 1968, Ser. No. 709,126 Int. Cl. B26b Z1 54 U.S. Cl. 30--346.58 6 Claims ABSTRACT OlF THE DISCLOSURE This disclosure is directed to a cutting blade such as a razor blade having a self-contained permanently attached guard whereby the blade holder may be of simple economical form and the normal guards or combs or other cutting edge protective means built into the blade holder may be omitted, the guard here comprising a thread having successively spaced portions arranged to extend beyond the cutting edge the spacing and thread diameter dimensions being of critical values, the thread being of a material which is flexible to enable it to be readily formed into the desired shape but having suitable stiffness and resistance to being severed when engaged against the sharpened blade edge.

THE PRIOR ART IN GENERAL The prior art contains many and varied proposals for the direct application in permanent or detachable forms of guard means. One class comprises the so-called hair Shapers where the guard usually has teeth of a coarse or u'ide dimension with wide spaces in between such as to receive readily the hair such devices being adapted for coarse operation and not for cutting close to the skin nor leaving a clean shaven surface.

A patent to Dickenson 1,035,548 issued Aug. 13, 1912, discloses a so-called straight razor having a long blade foldable into a slot in the handle, the blade having spirally wound thereon a wire or thread of other material to form a guard according to the description. However, the wire turns are shown as widely spaced with no indication or recognition of any criticality in the spacing of the successive loops of the wire nor of the wire diameter nor of any relation between the spacing and the wire diameter.

Other patents such as the more recent one to Ferrara 3,263,330 issued Aug. 2, 1966, disclose the application to a .razor blade cutting edge of a sheet material which has preformed therein a row of holes the sheet being folded over the edge on a line bisecting the successive holes leaving a strip over the edge between holes. Such an arrangement presents practical difficulties in satisfactorily applying such a sheet strip, one factor being that the sheet sections between holes need to be of substantial width for applying and securing the sheet in place but too wide intervening sections between holes tend to iron down and pass over some of the hairs,

SUMMARY OF THE INVENTION It has been found that a cutting blade with a selfcontained guard in the form of a thread having portions or sections arranged at and extending beyond the cutting edge and generally perpendicular to the cutting edge is surprisingly effective, dependable and safe in removing hairs close to the skin which employs in combination thread diameters and spacing between adjacent thread sections of certain critical values including the relation of the thread diameter and spacing one to the other. With the proper dimensions and relations gouging is avoided and danger of nicking of the skin is greatly minimized. A

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razor blade of this type can be mounted in a simple economical holder which does not require accurate geometry or close tolerances in the relationship of parts. The guards or combs normally built into the blade holder are not required at least insofar as safety and avoidance of skin cuts are concerned, although they may be embodied for other functions such as aiding to set up the hairs for the blade cutting. The blade can be freely handled `with little danger of cutting the handler or damage to the blade cutting edge from contact with hard surfaces. With the selected critical thread diameters and spacing between adjacent thread portions at the cutting edge the blade can be drawn across the skin logitudinally of the edge without cutting. In general a close safe shave can be obtained including the shaving in close narrow spaces as around the nostrils employing little or no skill.

Various adaptations and embodiments of the invention can be made to meet particular conditions and uses, including uses of cutting blades in areas outside the field of close shaving all within the criteria and principles of the invention, representative examples being illustrated in the drawings and described hereinafter. Referring to the drawings in general:

FIGURE 1 is a view in perspective of a representative type of blade having a guard thereon in the form of a continuous thread spirally wound thereon;

FIGURE la is a fragmentary view of a section of the blade of FIGURE 1 on an enlarged scale showing the threads partially embedded in the extreme blade cutting edge;

FIGURE 1b is an end view of a blade similar to that of FIGURE 1 with the spirally wound thread but in this case with the thread extending in the form of a loop outwardly beyond and spaced from the ultimate cutting edge of the blade;

FIGURE 2 is a view in perspective of a simple holder with a blade like that of FIGURE 1 mounted therein;

FIGURE 3 is a view in perspective of a double edge blade with the guard spirally wound thereon similarly to FIGURE 1;

FIGURE 4 is a View in perspective of a simple type of handle adapted to support a blade such as that of FIGURE 3;

FIGURE 5 is a vertical section on substantially the plane 5 5 of FIGURE 4 illustrating a means for securing the blade in the holder of FIGURE 4;

FIGURE 6 illustrates an application of the invention in a single edge backed blade of the type commonly referred to as a Gem blade;

FIGURE 7 is an end View of the blade of FIGURE 6;

FIGURE 8 is a further form of the application of a permanently secured thread type guard which in this case is applied solely to the beveled ank surface of the sharpened edge in a sinuous form;

FIGURE 9 is a fragmentary cross sectional view on an enlarged scale taken on a section 9 9 of FIGURE 8;

FIGURE 10 shows a continuous strip blade with the thread guard applied thereto in the form of a spirally wound continuous thread;

FIGURE 1l is a fragmentary View in largely diagrammatic form showing a holder for a continuous strip blade of the type indicated in FIGURE 10;

FIGURE 12 illustrates a manner of applying the 4threads to a blade adaptable particularly for injector razors;

FIGURE 13 is a fragmentary cross sectional view taken on the plane 13-13 of FIGURE l2 but on an enlarged scale;

FIGURIE 14 is a perspective View in elevation of a holder and blade assembly the holder in this case embodying a built-in guard or soap bar; and

FIGURE is a View in elevation of a holder supporting a pair of single cutting edge blades of the character concerned in this invention arranged in the holder with the cutting dege in opposed relation.

Referring rst to FIGURE l there is illustrated a sample application of the principles of the invention to a single edge blade 10 having a cutting edge 11. The blade may for example have the dimensions and proportions comparable to those of the present commercial blades of the injector type. Such a `blade could have a length of about 11/2 inches, a width of about 1A inch, and a thicknes of about .O10 of an inch.

The guard comprises a thread of small diameter applied in a manner to provide successive portions extending over and beyond the blade edge. Conveniently this is accomplished by spirally winding the thread 12 around the blade 10.

The thread may be of any type of material which is flexible and capable of conforming to the shape of the blade to which it is applied, and is capable of being pressed against the ultimate cutting edge of the blade under normal shaving pressures for example without severing the thread. Fine metal wire as for example of steel is particularly well adapted to the purpose, but other materials can be employed such as glass ber thread or some `synthetic such as a tough grade of nylon. Likewise the manner of securing the thread to the blade may vary dependent in some casesI upon the kind of material of which it is composed. One method may be of an adhesive such as one of the epoxy resin adhesives. Normally a band of adhesive extending longitudinally of one or both blade surfaces serves the purpose. The band may be considerably narrower than the blade and should in any case be spaced from the blade cutting edge. In the case of a metal thread it may be spot welded to the blade surface as indicated at 13 and each turn of the thread may be welded or the welding may be at regularly spaced turns with intervening turns unwelded. Ordinarily it may be suicient with a spirally wound wire to spot weld one or two thread passes at each extreme end of the blade. The blade cutting edge may also be coated with a friction reducing material such as polytetrauoroethylene coating as disclosed in the United States patent to Fischbein No. 3,071,- 856 and the coating applied either before or after the guard means. Coating after the guard means has been applied has the advantage that the thread has an outer coating which gives a smoother easier shave due apparently to the reduced drag on the skin.

Of critical importance in a shaving blade are the spacing and diameter of the thread. The diameter should he small enough to avoid ironing down of hairs at the areas of the threads and the spacing should be small enough to prevent too close contact of the skin with the cutting edge. There is, of course, a relation between the diameter of the thread and the spacing between threads, the larger the diameter of the thread the larger may be the spacing between threads and conversely, these factors being criti- :ally limited by the necessary requirements of catching all of the hairs without cutting the skin. It has been found that diameters in the range of about .O02 to .O10 of an inch may be employed with windings in the range of about 30 to 65 per inch, or perhaps a few more windings with `threads in the smaller end of the range. However, a better range of diameter size is about .002 to .006 3f an inch, and in most cases preferably in the range .0025 to .004. Typical examples are a thread diameter of `0025 of an inch with windings in the range of about 55 to 65 per inch; and a thread diameter of .004 of an inch with windings in the range of about 30 to 60 per inch. It has been determined that human hairs may in some :ases be as large as .010 of an inch in diameter' through :ommonly much smaller. Accordingly for general usage he net spacing between threads should not be less than `O10 of an inch. It may be noted as examples within the bove criteria a thread diameter of .002 lwith windings of Cit 60 inch results in a clear space between adjacent threads of a little less than .015 of an inch; and a thread diameter of .004 with 45 windings per inch results in a clear space of about .018 of an inch. Even with the larger diameter threads the free space between adjacent threads should preferably not exceed about .035 of an inch. Because of the small dimensions involved, particularly the thread diameter, it should be understood that for clarity of disclosure many of the apparent dimensions and relations indicated in the various gures are out of proportion.

When the thread is wound spirally around the blade in the form shown in FIGURE l some tension normally will be employed and as a consequence the respective passes over the thin delicate extreme cutting edge will be embedded to some extent as illustrated at 14 in FIGURE la. This localized breaking down of the edge does not affect the cutting since the broken area is fully occupied by the thread. Furthermore it has an overall advantage in that it insures that the threads are maintained in proper spaced relation. The degree of indentation has a bearing of course on the size of thread and spacing to be selected. Assuming a thread .004 of an inch in diameter it may be embedded .002 of an inch giving the guard a net lead in advance of the cutting edge of .002 of an inch. With such a small thread and corresponding small lead the spacing of the threads should be in the lower range.

The blade illustrated in FIGURE l may be mounted in any simple type of holder of inexpensive form such as that indicated in general in FIGURE 2 which has a head 15 and a suitable handle 16 the blade 10 being secured between a lower plate 17 and an -upper cap plate 18. Since the blade 10 has its own guard the razor does not embody any guard or comb elements as such, and the cutting edge of the blade 10 extends a substantial distance beyond the plates 17 and 18. The plate 17 may have a front locating means for the blade such as the lugs 19. The blade holder may be 0f metal 0r plastic and since it can be cheaply made the blade may be permanently secured in the holder and the razor as a whole disposable. If preferred, however, the cap plate 18 may be hingedly mounted in any suitable manner enabling the blade 10 to be replaced.

FIGURE 1b shows a modication of the blade of FIG- URE 1 in which the thread guard means 25 has loops 26 extending beyond and free of the ultimate cutting edge 27 of the blade 28. In this case the thread material must have a certain amount of rigidity such as would be afforded by a steel wire to avoid substantial deformation under shaving pressure. The lead or distance to which the loops 26 extend beyond the cutting edge 27 will vary dependent upon the circumstances. The thread diameter and spacing should take into account the amount of such leda. As a general rule, with the added lead the spacing between thread passes will be greater than when the thread is embedded as in the form of FIGURES 1 and la. The thread 25 can be spirally wound and secured in place as described with respect to the blade of FIGURE l. To form the loops 26 the thread winding means may include a small forming pin or wire located in front of the cutting edge over which the successive wire turns are looped, the pin being drawn along parallel to the cutting edge from successive loops as the spiral winding progresses. A razor embodying this type of blade would have particular advantage in a so-called Prep razor used in hospitals for removing longer hair preparatory to an operation, for example.

FIGURE 3 illustrates an application of the principles of the invention in a double cutting edge razor blade. If the blade is mounted in a holder of the type of that shown in FIGURE 4 it may be quite thin, as for example about .004 of an inch in thickness. In the case of the blade 30 of FIGURE 3 the guard is illustrated as comprising a spirally wound thread 31 such as a ne wire, the type of thread and the conditions and dimensions being of the character described more fully in connection with FIG- URE l. Likewise the manner of securing the thread in place may be in accordance with the description above in connection with FIGURE 1.

Any suitable holder may be provided for the blade and the dimensions and character of the blade and holder made compatible with each other. FIGURE 4 shows a holder having a base support plate 32 and a cap plate 33 forming a head mounted on a handle 34, the blade 30 being clamped between the two plate members by any suitable means. The razor may be of metal or plastic material and of economical construction and manufacture and assembly. The assembly may be permanent and the razor disposable or the cap 33 may be removable for replacement of the blade. One form of construction is illustrated particularly in FIGURE 5 in which the support plate 32 has an integral lug 36 at each end adapted to extend through a corresponding notch 37 in the blade and into a depression 38 in the cap plate 33, the plate 33 being held in position by a hook portion 39 at each end adapted to snap over and engage around the lower support plate 32.

FIGURES 6 and 7 illustrate an application of the principles of the invention to a single edge backed type of blade of the type sold under the trademark Gem Typically such a blade comprises the blade proper 41 having a U-shaped backing member 42 clamped over the back edge of the blade 41. In this case the guard may be likewise spirally wound on the blade member 41 before being clamped in the backing member 42 or arranged and secured in any suitable manner such as by weaving the thread back and forth and over and around the cutting edge 44. As illustrated at 45 .for example the thread has a return loop at 46. Once the backing member 42 is clamped in place the threads are securely held although additional securing means may be employed such as an adhesive securing the portions of the threads outside of the backing member 42. However, it will be understood that the blade 41 may be made much narrower than the ordinary Gem blade or the backing member 42 eX- tended farther toward the cutting edge 44 eliminating any necessity for additional securing means for the individual thread portions.

FIGURES 8 and 9 illustrate still another application of a permanently attached thread to a cutting blade. In this case the thread has a serpentine or sinuous form and is applied to the ground flank on one side of the blade the successive threads each being secured in place by appropriate means such as by spot welding at each of the strand portions as indicated at 52. In the case of Welding, the thread of course would need to be composed of metal. In any event it should have substantial stiffness so as to retain its shape under shaving or other cutting pressure. As in the case of the extending loop construction of FIG- URE lb the degree to which the loops extend beyond the cutting edge 53 will depend upon the circumstances including particularly the intended cutting purposes. In the case of a razor blade the projection beyond the cutting edge 53 may appropriately be in the range of up to about 1/32 of an inch.

Blades of the types shown in FIGURES 6 and 7 and 8 and 9 can be mounted in a simple economical type of holder designed to be disposable or capable of replacementof the blades as desired. There are various hinged cover razors of a type adapted to receive a blade such as that of FIGURES 6 and 7 which may be employed in the event it is desired to make the blade replaceable. Either of these two types of blades can of course be employed in a simple razor like that depicted in FIGURE 2.

FIGURES and 11 illustrate the application of a guard of the type concerned here in a razor blade of the continuous strip form adapted to be employed in razors of the general type shown in such patents as Jones 2,492,292, Iones 2,591,702 and Nissen 3,262,198. In razors of that type the strip is a narrow thin band typically about 37/15 of an inch wide and having a thickness in the range of about .0015 to .005 of an inch.

FIGURE 10 shows in plan a section 60 of such a type blade band. The blade band may have a sharpened cutting edge at either or both longitudinal edges. Spirally Wound thereon is the thread 661, the diameter of the thread such as a fine metal wire and the spacing of the coils being in accordance with the criteria described heretofore in connection with the blade of FIGURE 1. Likewise the individual coils may be secured in place by suitable means similar to those described in connection with FIGURE 1. In other words it may be by means of for example an adhesive or spot welding. The winding operation normally involves some tension in the thread 'and corresponding indentation of the thread at the extreme cutting edges as described in connection with FIGURE la.

FIGURE 11 illustrates in simple and sometwhat diagrammatic form a blade holder of the general type concerned suitable for mounting the present blade with its self-contained guard. Accordingly the razor has a head portion 63 with a handle 64 extending therefrom, the head 63 being adapted to hold a cartridge having a pair of reels 65 and 66 one of which is the initial supply reel and the other the take-up reel, the blade being advanced successively in steps from the supply reel to the take-up reel lby suitable manually operating means which the foregoing noted -patents illustrate. In the present case, however, the blade carries its own guard which functions in shaving but also protects the blade in handling and feeding from one reel to the other, and suitable guides may be provided without danger of injuring the cutting edge such as the hollow loops 67 and 68 arranged at opposite `ends of the stationary bar 69 on which the blade 60' rides.

Assuming each longitudinal edge of the blade strip is a sharpened shaving edge the blade strip extends laterally of the supporting bar 69 a substantial distance such as at least j/16 of an inch and of course no auxiliary guards or comb in the blade holder are required. If it is a single cutting edge band the bar 69 may include a vertically extending flange constituting a back rest and guide against which the unsharpened edge engages. If the blade strip has suiicient stiffness and is under tension the supporting bar 69 may be omitted or at least the mid portion thereof omitted whereby the blade at that region may by moderate pressure be made to conform substantially with the area being shaved.

FIGURES 12 and 13 illustrate a method of applying a guard of the type here concerned to provide a blade especially adapted for use in an injector razor and an injector blade dispenser. The blade 70 which may be of standard injector type and size has threads 71 applied thereto which may be metal and spirally wound thereon. The blades which at this stage may be in a continuous strip form are then fed through a welding means which has opposed electrodes such as of disc shape which produce welds at the points 72, 73 located on the ground facets of the blade.

Following that Operation the blade strip `continues through a thread shearing means comprising a pair of opposed cutters adapted to shear the threads immediately to the rear of the weld points and the portions of the threads shown in 'broken lines in FIGURE 12 are freed and removed leaving a blade such as shown in FIGURE 13 having the guard sections 71a. It will be noted that the weld points 72, 73 and the guard sections 71a are inside the projected planes of the flat surfaces of the blade and accordingly the blades may be arranged flatwise in full surface Contact in a stack and dispensed and otherwise handled in the normal manner.

As illustrated in the various forms thus far described and blade of the invention embodies its own permanently self-contained guard means. It may be desirable in some applications to include in the assembled razor a built-in guard or soap bar which may be generally similar to the conventional forms of guards. FIGURE 14 illustrates one such form or application. The holder maybe generally similar to that of FIGURE 2 with a head 81 in which is mounted the blade 10, the head including a top plate 82 and a bottom plate 83, the latter having a pair of lugs or hooks 84 against which the cutting edge is engaged. In this case, however, the bottom plate includes an extension in the form of a downwardly curved bar 85 having a slotted opening 86 for escape of soap corresponding to the guard or soap bar normally embodied in an injector type razor. Since the blade, in the present case, however, embodies its own guard, the bar 85 need not be designed and located to serve as a guard primarily but more as an auxiliary means in this respect acting to smooth down the surface and aid in setting up the hairs for engagement by the blade. Accordingly the spacing between the bar and the blade edge and the shaving angle are not critical and not required to be held to any close dimension and in general the spacing may be larger than in a razor with a normal plain blade.

FIGURE 15 discloses a razor 90 employing a pair of blades 81, 92 which may be equipped with guard means similar to that of FIGURES l and 1a or FIGURE 1b, the blades being arranged with the cutting edges opposed A clearance space 93 is provided for soap and debris. In this construction and relation of the elements one guarded blade acts as an auxiliary guard for the opposite one. In other Words when, for example, the razor is moved to the left in FIGURE l and blade 91 is on a cutting stroke the opposite blade 92 acts as a guard and soap bar. In addition the holder may be provided with top rounded portions 94, 95 which also are adapted to bear against the skin 96 as indicated in the figure. Preferably the razor head is freely pivoted to the handle at 97 whereby when the pressure is appropriately applied at the handle the head assumes a balanced position with both rounded bearing portions 94, 95 in contact with the skin.

Since further forms and modifications of the guarded blade may be made in addition to those disclosed herein and different embodiments of the invention made without departing from the scope of the invention, it is intended that all matter contained herein shall be interpreted as illustrative and not in a limiting sense I claim:

1. A razor blade with a self-contained guard in the form of a plurality of spiral windings of a thread firmly attached to the blade, said windings being spaced along and extending around the cutting edge, said thread being of exible material capable of being pressed against the razor blade edge by normalshaving pressure without severance of the thread, said thread having a diameter within the range of .0025 to .006 of an inch and the spacing between adjacent windings of said thread being uniform and in the range of .010 to .035 of an inch.

2. A razor blade in accordance with claim 1 wherein the thread is a metal wire and is attached to said blade by welding.

3. A razor 4blade in accordance with claim 1 wherein the thread is attached to said blade with an adhesive.

4. A razor blade in accordance with claim 1 Wherein .the diameter of said thread is within the range .0025 to .004 of an inch.

S. A razor blade in accordance with claim 1 wherein the windings of said thread are embedded for a portion of the diameter of said thread in the extreme cutting edge of said blade.

6. A razor blade in accordance with claim 1 wherein both the blade cutting edge and said thread have a polytetrauoroethylene coating thereon.

References Cited UNITED STATES PATENTS 1,035,548 t8/1912 Dickenson 30-78 1,270,783 7/1918 Cartlidge 30--78 2,794,246 6/1957 Marsh et al. 30--77 X 3,263,330 8/1966 Ferrara 30-346.56

FOREIGN PATENTS 836,027 10/1938 France.

97,254 6/1898 Germany.

OTHELL M. SIMPSON, Primary Examiner J. C. PETERS, Assistant Examiner U.S. Cl. X.R. 30-78 gg UNI'IED STATES PATENT OFFICE CETIFICATE OF CRRECTIN patent No. 3,505,734 lDated April 14, 1970 Inventores) Acumulus A. ITEN It is certified .that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

f- Col. 3, line 4, "dege" should read edges -4- Col. 3, lines 5-6 "sample" should read simple Col'. 3, line 29, after "be", "of" should read by Col. 3, 1:L ne 71, through" should read though Col. 4, line 52, "leds" should read lead Col. 6, line 4, "661" should read 6l Col. 6, line 70, "and" should read the Col. 7, line 13, before "surface" insert VA skin Col. 7, line 20, "81" should read 91 -i- SlGNED Ms I SEALI Aus 1 mgm l (SEAL) Mmewlmlr mlm n. Mmmm, JR. Edwm? Gomissione'r of Patents AOW" A

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