US3274686A

US3274686A - Laminated razor blade for injector razor

Info

Publication number: US3274686A
Application number: US436438A
Authority: US
Inventors: Dawidowicz Jan
Original assignee: Eversharp Inc
Current assignee: Eversharp Inc
Priority date: 1965-03-02
Filing date: 1965-03-02
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27
Also published as: DE1286430B; NL6602712A; SE314610B; GB1065933A

Description

Sept. 27, 1966 J. DAWIDOWICZ LAMINATED RAZOR BLADE FOR INJECTOR RAZOR Filed March 2, 1965 2 Sheets-Sheet 1 INVENTOR.

TAN DAWIDOWICZ "5 L/ E, M M

WV O O A M 4 M -5 ATTORNEYS Sept. 27, 1966 J. DAWIDOWICZ LAMINATED RAZOR BLADE FOR INJECTOR RAZOR Filed March 2, 1965 2 Sheets-Sheet 2 FIG. 5

FIG. 4

FIG. 3

INVENTOR- U'AN DAWIDOWICZ Fifi ATTORNEYS United States Patent M 3,274,6fi6 LAMHNATED RAZOR BLADE FOR INJECTOR RAZOR Jan Dawidowicz, Fairficld, Conm, assiguor to Eversharp, lam, Milford, Conn, a corporation of Delaware Filed Mar. 2, 1965, Ser. No. 436,438 3 Claims. ((311. 30-348) This invention relates to a laminated razor blade for an injector razor and to the method of making the same.

Safety injector razors are constructed with spring biased compression means for holding a single-edge razor blade in the razor head with the cutting edge of the blade extending out from a guard bar in its safety cutting position. These razors are designed to receive a single-edge blade as it is injected laterally into the head from an injector device that holds a surplus of the razor blades. The injector razor is specifically designed so that upon insertion of the blade into the razor head the leading end edge of the blade will come into abutting contact with the end edge of the used blade already positioned in the razor and will push the used blade out of one side of the razor head while the new blade is being inserted. In order to effect good abutting contact between the end edge of the blades, it is essential that the blade have sufficient cross-sectional thickness to present a suitable surface area for abutment. For this reason injector razor blades have always had a cross-sectional thickness more than twice the cross-sectional thickness of the standard double-edge razor blade. Any attempt to use a razor blade having the cross-sectional thickness of a standard double-edge razor would be inoperative because the thin cross-sectional thickness would not provide a good abutting surface between old and new blade during reloading and the new blade would fail to abut properly and become inserted over or under the old blade without displacing it out of the razor head.

In increasing the cross-sectional thickness of the injector blade, formation of the cutting edge is made more dilficult and the cutting edge formed is not comparable to the quality cutting edge which is formed on the thinner standard double-edge blades. The reasons for the poorer cutting edge formation are obvious; since the thickness of the injector blade is so relatively large, the amount of material which must be removed is greater. Furthermore, there is a limitation on the diameter of the grinding wheels which can be used and this has necessitated a first grinding operation to form a cutting edge and at least two subsequent honing operations in order to get an effective thin cutting edge on the blade. With the thinner standard double-edge blades, material removal is substantially less and the cutting edge realized is substantially sharper.

I have developed a razor blade for use in injector razors which utilizes a thinner blade than that heretofore used and laminates to it reinforcing strips which increase its thickness and rigidity so that it can be used in combination with the present injector razors. More specifically the invention involves the pragmatic utilization of the already mass produced standard double-edge blades with thin superior outing edge properties, in combination with strategically positioned reinforcing strip to construct an injector razor blade which has a superior cutting edge While retaining all the advantageous features of injector razors, including the ease of injection loading.

Broadly stated, my invention is for use in combination with a safety injector razor having spring compression means for holding a razor blade in a safety cutting position, in which a new razor blade is loaded into the razor head in the safety cutting position relative to safety guard by laterally forcing the blade into the head and 3,274,686 Patented Sept. 27, 1966 abutting one end edge of the new blade against a corresponding end edge of a used blade positioned within the head, and laterally pushing the used blade out of one side of the razor head while forcing the new blade into the other side. The improvement comprises a thin flat metal blade with a cutting edge formed along one elongated edge of the blade, and a thin flat reinforcing strip attached to at least one elongated edge of the blade with their respective broad faces in faceto-face adhesive bond to define a composite blade having a substantially flat and uniform thickness with the end edge of the blade and reinforcing strip defining with their combined thickness an edge surface area sufiicient for abutting contact with a corresponding edge surface area on the end edge of a similar blade. One side edge of the reinforcing strip extends parallel to but is spaced from the cutting edge so that the cutting edge extends from the side edge of the reinforcing strip an extent sufiicient to extend the cutting edge out of the head of the razor in safety cutting position relative to the safety guard on the razor head.

The invention also relates to the laminated razor blade per se with a reinforcing strip attached to either one or both broad surfaces of the blade.

A method of forming the single-edge laminated injector razor blade from standard double-edge razor blades is also presented. This method consists of successively positioning double-edge razor blades at a first station and positioning a thin flat reinforcing strip against at least one of the fiat surfaces of the blade at the first station with their respective faces in face-to-face contact with an adhesive bond therebetween. The blade and strip are then successively fed to a sealing station at which the blade and strip are adhesively bonded together as positioned to define a composite blade having a combined substantially flat and uniform thickness. The laminated blade and strip are then separated to form two identical singleedge laminated injector razor blades. According to the method the reinforcing strip can be applied to one or both surfaces of the blade.

A preferred embodiment of the invention is described hereinbelow with reference to the drawings wherein:

FIG. 1 is a step-wise illustration of the method of forming the laminated single-edge razor blades from doubleedge blades;

FIG. 2 is a side view of single-edge laminated injector razor blade;

FIG. 3 is a section of the single-edge laminated injector razor blade taken along lines 33 of FIG. 2;

FIG. 4 is a section of a second embodiment of a singleedge laminated razor blade having only one reinforcing strip laminated thereto; and

FIG. 5 is a section of a safety injector razor head with a laminated razor blade positioned therein in its safety cutting position.

Referring initially to FIG. 1, a method of forming the laminated razor blades of the invention in a series of continuous steps is shown. A continuous thin fiat reinforcing strip 10 of aluminum of a thickness of from about .003 to about .005 inch is successively fed to a feeding station 11, preferably by a Ferguson indexing mechanism. At the feeding station 11, a standard double-edge razor blade 12 which has previously been ground to form the finished cutting edges 13 and 14 is located above the reinforcing strip 10 and is positioned on the strip against one of the flat broad surfaces thereof with their respective broad faces in face-to-face contact with an adhesive layer 15 therebetween. The adhesive layer is preferably a thermal setting adhesive which is pre-coated on the surface of the reinforcing strip that will be placed in contact with the broad surface of the razor blade so that the adhesive layer will be positioned at the interface therebetween. The

blade can be stainless steel and can be coated with a silicone or polytetrafiuorethylene as is known in the art.

The aluminum reinforcing strip is coated with an ad-.

hesive in advance to form an adhesive coated aluminum strip available as Plymaster FN-98A (Pittsburgh Plate Glass Company trade name) The aluminum used for the strip was 5052 H-38 alloy. The adhesive coated aluminum strip is prepared by coating it with a liquid adhesive which consists essentially of a combination of a butadieneacrylonitrile copolymer and curing phenol-aldehyde resins in a volatile ketone solvent. About 1 dry mil of this adhesive is coated on the strip and then the solvent is substantially completely evaporated at a temperature range progressing from about 140 F. through 260 F. in 5 to minutes. The dried adhesive-coated aluminum is wound up continuously with a polyethylene interleaf so as to permit easy unwinding.

Another example of an adhesive which is coated on the reinforcing strip in the same manner as that just described is the following:

Ingredients: Parts by weight Hycar 1042 100 CKR 2620 150 Methyl ethyl ketone 350 This adhesive is prepared by first milling the Hycar for approximately 5 minutes on a standard two roll rubber mill at a mill temperature of about 150 F. All of the ingredients are then charged into a Struthers-Wells internally agitated mixer; complete solution takes place in about 8-12 hours. The final liquid adhesive has a viscosity range of about 500-2000 cps. as measured on a Brookfield RVF viscosimeter at 25 C.

Hycar 1042 (trade name of B. F. Goodrich, Chemical Division) is a butadiene-acrylonitrile copolymer; it contains about 65% by weight butadiene and 35% by weight acrylonitrile. It is a rubbery solid having a specific gravity of 0.98 and a Mooney viscosity of '70-95.

CKR 2620 (trade name of Union Carbide Company) is a phenol-aldehyde resin, which is an alkaline catalyzed resin which is the reaction product of mixed phenols and an excess of formaldehyde. The resin exists as an amber colored lump; it is thermosetting; and its specific gravity is about 1.24 with a melt point of about 200 F.

In one example, the second adhesive was used to bond the reinforcing strip to a stainless steel razor blade in a flat platen press. The platen on the aluminum side was heated to a temperature range of 325350 F., and the bond was effected in a 5 second cycle at 25-50 p.s'.i. The bonded reinforcing strip and blade were tested by peeling the reinforcing strip from the razor blade at a rate of 3 inches/minute and at a peel angle of 180. The bond made and tested this way had a peel strength of 10-12 lbs/inch and this was satisfactory to resist separation in normal use.

As shown, the blade has a width of about 0.736 to about 0.738 inch from cutting edge to cutting edge, and the width of the strip from edge to edge is about 0.625 inch. Elongated bayonet slots 20 and 21 of about .085 inch in width are cut out of the center portion of both the blade and reinforcing strip and are used for insertion of a bayonet member of the indexing mechanism for guiding the strip and blade from station to station. Pairs of longitudinally spaced

holes

22 and 23 are provided between the bayonet slots 20 and 21 and the edges of the strip and blade which are positioned in alignment with each other when the blade and strip are placed in faceto-face position at the first station. As will be seen these holes are positioned to receive pins of an indexing mechanism for moving the blade once the blades have been cut into single-edge blades and the bayonet slot has been destroyed.

At the first station 11, the reinforcing strip and blades are tack welded at portions 25 and 26, which are portions that will be cut off subsequently in the formation of the blade and will not form a part of either of the single-edge blades being prepared. The blade and reinforcing strip joined together by tack welding are then moved intermittently by the indexing mechanism to a second station 27 where a reinforcing strip 28 of the same thickness as the first reinforcing strip is placed over the broad surface 29 of the blade so that second strips bayonet slot 30 and pairs of holes 31 align with those of the blade and reinforcing strip as described. The reinforcing strip 28 is precoated with an adhesive on its broad face as described above. When the reinforcing strip is positioned on the blade, the broad face of the reinforcing strip with the adhesive thereon and the broad face 29 of the blade respectively are in face-to-face contact with an adhesive layer therebetween in locations identified by

numerals

57, 58 and 70 as shown in FIGS. 3 and 4. The reinforcing strip 28 is then tack welded to the blade at portions 38 and 39 which portions will subsequently be removed.

The blade with the reinforcing strips tacked to its broad surfaces is then fed to a first sealing station 40 where heat and pressure is applied to the assembly causing the reinforcing strips to become adhesively bonded at the interface between the broad surfaces. A second sealing station 41 may also be provided to heat and pressure seal a second time to insure formation of a good adhesive bond therebetween. It is contemplated that a typical output from the continuous formation will be about 200250 units per minute and the two station sealing time will be /3 second at 350 F.

Subsequent to the heat sealing operation, the assembly moves to a first blanking station 42 which removes the center portions of the laminated assembly so as to create two continuous fabricated strips of injector blade assemblies. The severed blades are then fed to a second blanking station 43 by an indexing mechanism which has pins which are insertable into the pairs of holes for moving the blades intermittently along, where they are severed into individual laminated blade assemblies. The finished blade assemblies are then fed to a loading station at which they are loaded into injector blade feeding devices. In the first blanking operation a substantially hexagonal portion 44 is removed from between the strips, which removes the portions of the laminated assembly at the ends of the bayonet slots and this serves to separate the assembly longitudinally. It also puts a 45 angle 45 at edge of the assembly opposite to the cutting edge. A similar 45 angle 46 is defined at the cutting edge because of the formation of the cutting edge at this point. The second blanking operation removes a portion 47 of the assembly between the continuous single edge blade assemblies, to provide an end edge 48 which has sufficient cross-sectional thickness to define a surface area large enough to permit engagement of the end edge portions of similar blades in abutting contact.

In FIGS. 2 and 3 the single-edge laminated injector razor blade 50 resulting from the practice of the method is shown. It comprises a thin flat metal razor blade 51 of about 0.327 inch in width with a cutting edge 52 formed along one elongated edge of the blade. A first thin flat reinforcing strip 53 of about 0.271 inch in width is adhesively bonded to one flat broad surface 54 of the blade, and a second thin flat reinforcing strip 55 is adhesively bonded to the other flat broad surface 56 of the blade with said respective broad faces of the reinforcing strips and blade in a face-to-face adhesive bond with

adhesive layers

57 and 58 at the interfaces therebetween. This defines a composite blade assembly having a combined substantially flat and uniform thickness not greater than about 0.012 inch, with the end edges 59 and 60 of the blade and reinforcing strip being coextensive and defining with their combined thickness end edge surface areas suffiicent for abutting contact with a corresponding edge surface area on the end edge of a similar blade. The interfacial adhesive bond between the reinforcing strips and the blade must be sufiicient to prevent separation therebetween at this interface from the combined compressive and shearing forces on the blade as it is advanced laterally into the spring compression means of the razor head.

It is also to be noted that side edges 61 and 62 of the first and second reinforcing strips extend parallel to but are spaced from the cutting edge by about 0.056 inch so that the cutting edge extends from the side edge of the reinforcing strip an extent sufficient to extend the cutting edge out of the head of the razor in safety cutting position relative to the safety guard of a razor head, as will be seen. The opposite elongated side edges 63 and 64 of the first and second reinforcing strips are coextensive with the elongated edge 65 of the blade.

In FIG. 4 a second embodiment of a laminated razor blade is shown. This razor blade 66 consists of a thin flat metal razor blade 67 with a cutting edge 68 along one side thereof and a single thin flat reinforcing strip 69 adhesively bonded thereto in the same manner as described in relation to the first double laminated embodiment with an adhesive layer 70 therebetween. It also has the same dimensional characteristics except that the reinforcing strip is from about .004 to about .008 inch thick and preferably nearer the upper range. Of course the razor blade assembly with the single reinforcing strip will be formed according to the same method described in relation to FIG. 1, the only exception being that the lamination of the second reinforcing strip to the blade will be omitted.

In FIG. 5 a standard injector safety razor head 71 and a portion of the handle 72 are shown. Basically the head assembly consists of a main frame member 73 which is spring biased toward a blade seat member 74 to provide a compressive force on a laminated blade 75 positioned therebetween to hold it in position. A pair of marginal portions, only one of which is indicated as 76, of the blade seat are positioned to abut against the 45 angle portions at the ends of the cutting edge to hold the blade from extending out of the head too far. A guard bar 77 is provided to prevent the cutting edge from being exposed out of its safety cutting position. Of course in loading injector razors of this type a new blade is forced laterally into the head and one end edge of a new blade is abutted against a corresponding end edge of a used blade positioned within the head. Continued forcing of the new blade in abutment with the old blade pushes the old blade out of one side of the razor while laterally inserting the new blade into the position shown in FIG. 5.

Obviously blades having the thickness of the standard double-edge blade could not be abutted because the thickness is too small. By adding reinforcing strips as described, so as to increase the thickness, while still retaining the superior cutting edge characteristics of standard double-edge blades, the advantages of the injector razor are combined with the advantages of a double-edge razor blade to give a superior product.

I claim:

1. A laminated razor blade for use in an injector razor comprising a thin flat metal razor blade of resiliently flexible material having a thickness of no greater than about .005 inch, a cutting edge formed along at least one elongated edge of said blade, a thin fiat reinforcing strip having a thickness from about .003 to about .008 inch attached to at least one of the flat surfaces of the blade with their respective broad faces in a face-to-face adhesive bond to define a composite blade having a combined flat and uniform thickness with the end edge of the blade and reinforcing strip defining with their combined thickness an edge surface area suflicient for abut-ting contact with a corresponding edge surface area on the edge of a similar blade, one side edge of the reinforcing strip extending parallel to but spaced from the cutting edge, whereby the cutting edge extends from the side edge of the reinforcing strip an extent sufficient to extend the cutting edge out of the head of the razor in safety cutting position relative to the safety guard of an injector razor.

2. A laminated razor blade according to claim 1 wherein said reinforcing strips are aluminum and the razor blade is stainless steel.

3. A laminated razor blade according to claim 1 comprising two reinforcing strips, each reinforcing strip adhesively bonded to one of the two broad faces of the blade, said blade having a thickness from about .004 to about .005 inch and each of the reinforcing strips having a thickness of from about .003 to about .005 inch, with the combined thickness of the blade and reinforcing strips being not greater than about .012 inch.

References Cited by the Examiner UNITED STATES PATENTS 794,798 7/ 1905 Heckel.

858,701 7/1907 Brokamp et al 76l04 929,059 7/1909 Week 30348 1,458,192 6/1923 Nickerson 30-348 1,734,554 11/1929 Behrman 76l04 1,916,416 7/1933 Connolly 76l04 2,335,472 11/ 1943 Auerbach. 2,937,976 5/1960 Granaham et al 30-346 2,983,045 5/1961 Diatikar 30-73 X 3,111,756 11/1963 Kruger et al 3063 3,128,551 4/1964 Crown 3063 FOREIGN PATENTS 498,465 2/ 1951 Belgium.

1,264 1/ 1884 Great Britain.

WILLIAM FELDMAN, Primary Examiner.

MYRON C. KRUSE, Examiner.

Claims

1. A LAMINATED RAZOR BLADE FOR USE IN AN INJECTOR RAZOR COMPRISING A THIN FLAT METAL RAZOR BLADE OF RESILIENTLY FLEXIBLE MATERIAL HAVING A THICKNESS OF NO GREATER THAN ABOUT .005 INCH, A CUTTING EDGE FORMED ALONG AT LEAST ONE ELONGATED EDGE OF SAID BLADE, A THIN FLAT REINFORCING STRIP HAVING A THICKNESS FROM ABOUT .003 TO ABOUT .008 INCH ATTACHED TO AT LEAST ONE OF THE FLAT SURFACES OF THE BLADE WITH THEIR RESPECTIVE BROAD FACES IN A FACE-TO-FACE ADHESIVE BOND TO DEFINE A COMPOSITE BLADE HAVING A COMBINED FLAT AND UNIFORM THICKNESS WITH THE END EDGE OF THE BLADE AND REINFORCING STRIP DEFINING WITH THEIR COMBINED THICKNESS AN EDGE SURFACE AREA SUFFICIENT FOR ABUTTING CONTACT WITH A CORRESPONDING EDGE SURFACE AREA ON THE EDGE OF A SIMILAR BLADE, ONE SIDE EDGE OF THE REINFORCING STRIP EXTENDING PARALLEL TO BUT SPACED FROM THE SIDE EDGE, WHEREBY THE CUTTING EDGE EXTENDS FROM THE SIDE EDGE OF THE REINFORCING STRIP AN EXTENT SUFFICIENT TO EXTEND THE CUTTING EDGE OUT OF THE HEAD OF THE RAZOR IN SAFETY CUTTING POSITION RELATIVE TO THE SAFETY GUARD OF AN INJECTOR RAZOR.