US2809477A - Razor blade strop and method of using the same - Google Patents

Description

OGL 15, 1957 D. E. KEEcH 2,809,477

RAZOR BLADE STROP AND MTHOD OF USING THE SAME Filed June 25, 1956 1&6. c?. Maf. z2/16.6'.

IN VEN TOR.

United States atent This invention relates to the stropping of razor blades and has particular utility in stropping the edges of safety razor blades of wafer-like thinness.

it has long been known that the edge of a safety razor blade may be stropped by the simultaneous application to opposite faces of the blade of stropping elements made of leather or rubber and then, while the blade is placed under pressure from said elements, withdrawing the blade from between said elements in a direction at right angles to said edge. in spite of this knowledge, how ever, an inexpensive and satisfactory razor blade strop operating on this general principle has not heretofore een provided.

lt is an object of this invention to provide a simple, inexpensive razor blade strop which can be manipulated manually in the manner above indicated to strop a razor blade and which will have a relatively high degree of etiiciency in producing a keen shavinLT edge on said blade.

The razor blade strops of the general type mentioned and heretofore developed have been based on tie princi le of applying pressure to the blade throughout its length simultaneously. l have discovered that while theoretically an advantage, this feature has two distinct disadvantages. lt causes the device to be unnecessarily large and by spreading the pressure applied thereto uniformly over the entire blade edge, it robs the device of the capacity to apply a carefully adjusted and relatively high degree of pressure to successive areas of the blade edge. have also discovered that the application of such high opposing pressures to local areas of the blade edge is the secret of attaining uniformly good stropping by this method.

it is therefore-another object ofthe present invention to provide a finger manipulated razor strop and method of using the same in which the blade is compressed between two stropping elements pressed thereagainst by the fingers to strop the blade edge, in which a relatively high Vpressure may be applied in opposite directions to a small area ofthe blade edge while withdrawing the blade from between the stropping elements.

Another feature-common to strops of thisV general type produced in the past has been the backing of the stropping element with metal plates which-greatly inhibits the dow of a rubber stropping element about the microscopic metal particles of the blade edge when the blade is being withdrawn-from between the stropping elements.

it is an Vobject' of the present invention to provide a finger manipulated razor blade strop and method of using the same in which the stropping elements are free to respond to the fleshy tips of the iingers and thumb, by which they are applied, so as to closely conform to the beveled faces of the razor blade adjacent the edge particles to beV stropped whereby the material of the stropping elements will flow over these bevelled faces, while said elements are pressed thereagainst with a relatively high local pressurepand the blade is being simultaneously withdrawn from between said elements.

lt is a still further object of t .e invention to provide rice a razor strop including a pair of opposed stropping elements in which the whole strop including said stropping elements and the means for connecting the same and holding these resiliently in spaced relation ready to have the fingers applied thereto is comprised entirely in a single molded article.

ln razor blade strops in the kprior art of the type being discussed the stropping elements were presented so as to cause occasional accidental collision of the razor blade edge with one of the stropping elements while the razor blade was being inserted edge rst between these elements. Such collisions, of course, damage both the strop and the razor blade edge and seriously impair the utility of the strop.

It is another object of the present invention to provide a razor blade strop of the general type mentioned which will render such accidental collision of the razor blade edge with the strop, while said blade is being inserted between the stropping elements, relatively easy to avoid.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a perspective view of a preferred embodiment of the invention.

Fig. 2 is an end elevational View of Vthe strop shown in Fig. l with the strop held between the thumb and forefinger of one hand and showing how a single-edged razor blade may be inserted, edge first, between the stropping pads without likelihood of the cutting edge colliding with the strop while the blade is being so inserted.

Fig. 3 is a View similar to Fig. 2 and shows the next step in applying the strop to the blade in which the stropping pads are pinched together until the extremities come in contact with the blade. This View also shows the steep convergence of the stropping pads as they are thus brought into contact with the blade which feature also operates to prevent collision between the blade edge and the strop.

Fig. 4 is a View similar to Fig. 3 and illustrates the next successive step in applying the strop to the razor blade. In this step the stropping pads are pinched to` gether on the blade so as to enfold the blade edge between the opposed stropping pads and apply substantial pressure from the thumb and forelinger through certain localized areas of said pads to the blade edge. This view also illustrates in broken lines, the step of withdrawing the razor blade from between the stropping pads when the latter are thus pinched against the blade edge.

Fig. 5 is a face View of a single-edged razor blade and showing the strop of the invention applied as in Fig. 4 to press the stropping pads thereof against opposite sides of a specific local area of the edge portion of said blade at one end of the latter. This view also shows in dotted lines how the entire edge of said blade may be stropped byapplication of the strop successively to similar like areas consecutively located along the edge portion of the blade.

Fig. 6 is a face view of a double-edged razor blade showing a pair of said strops applied thereto with corresponding local areas of the respective cutting edge portions of said blade gripped by the application of said strops thereto in similar manner to that'shown in Fig. 4. This view also illustrates how similar consecutively related areas of the blade edge portions may be strapped by successive applications of the two strops to said blade.

Fig. 7 illustrates the manner of using the invention to strop a double-edged bla-de and shows an end view of such a blade with a certain area of one edge portion of said blade gripped by one of said strops and with the blade manipulated, through the grip with which it isthus held,

Vedged blade.

to insert the opposite vedge portion of the blade between the stropping pads of the second strop. Y

Fig. 8 is a view simila-r to Fig. 7 showing the completion of the lapplication of two strops in gripping relation with opposite localareas of the two edge portions of a double-edged blade. Y

Fig. 9 illustrates the next step inV stropping a double- This View shows how excessive pressure is applied in gripping one edge portion of said blade withV one of said strops and a somewhat less pressure applied to the opposite edge portion of the blade by the other strop, and the two strops then pulled apart so as to slip the second strop away from its gripping relation with the razor blade, thus stropping'that area of the edge portion of said blade which was gripped between the pads of the second strop.

Referring specifically to the drawings and particularly to Fig. l, the embodiment ofthe invention disclosed therein comprises an approximately U-shaped integrally molded soft rubber strop 10, including opposite side elements 11 which comprise soft rubber stropping pads n flat sheet form, and an arcuate middle connecting element 12 lwhich is preferably of the same thickness as the pads 11.

The inner faces 15 of the padsV 11 of the strop 10 are smooth land the strop is preferably made of black carbon impregnated butyl rubberY with ya hardness of 50 durometers. i

The strop of the invention may have any preferred external surface characteristics but it isV highly preferable thatthe inner stropping pad faces be smooth. The strop 10 is adapted for stropping a sharpened edge of a safety razor 'blade including the well known single-edged blade 16 (Figs. 2-5) or the well known double-edged blade 17 (Figs. 6-9).

Reference will now be m-ade to Figs. 2 to 5 inclusive, which illustrate the various steps of the method of the present invention as this is performed by applying strop 10 thereof in sharpening a single-edged blade 16. Y The first step in performing this method is illustrated in Fig. 2 where one of the strops 10V is shown as held lightly between the thumb and forefinger of one hand while a blade 16 is held by the metal shod4 edge Y18 thereof in the other h-and and the sharpened edge portion' 19 of the blade, with cutting edge21 thereof in the lead, is inserted into the relatively wide U-shaped mouth of the strop 10. This view shows the latitude allowable in introducing the blade edge 21 b'etween the stropping pads 11 of the strop 10 of the inventionrwithoutany collision being inadvertently produced between theA 'blade edge and the rubber of the strop. Obviously, any such collision would be injurious to both the strop and the blader edge and must be avoided for the advantages of using the strop to be fully realized.

While holding the blade 16 with the sharpened edge portion 19 thereof inserted between the strop pads 11, the latter are pinched together between the thumb `and forenger, which results in these pads assuming an increasingly steep convergence toward eachother and toward the razor blade, culminating in the free edges of the pads engaging the yblade as shown in Fig, 3. This manner in which the pads approach and recede fromthe blade prolikelihood of a collision between the razor. blade edge 21 and the material of the strop. Y

Vvides an additional circumstance, tending to` prevent the Y The step shownV in Fig.'3 is followed immediately by added pressure being applied to the strop pads 11 from the thumb and foreiinger holding the strop which results in bringingthe pads 11 into parallel-clamping relation with the edge portion 19 of theblade 16 `as shown in Fig. 4. This application of the strop 10 to the edgeportion 19 of the blade 16 is preferably selected so that'the area 25 in which the pressure fromthe thumb and foreiinger` is;Y

transmitted through the stropping pagdsll to the blade 16 A stropping action is now produced on that portion of the blade edge 21 lying within area 25 'by withdrawing the blade 16 from between the strop pads 11 in the direction of arrow 26 at a right angle with the blade edge 21 while maintaining a substantial pressure on said blade edge portion in area 25 thereof through said pads. Following this stropping of that part of the Yrazor 'blade edge 21 ernbraced by area 25, the same stropping operation just described for this area is repeated for similar areas 28 and 29 which areas consecutively overlap each other and, taken together, embrace the entire. cutting edge 21 of the blade 16. Y

A fairly good stropping of the cutting edge 21 of the blade 16 may be accomplished by covering the entire blade edge only once with a series of stropping operations as above described. A better stropping is sometimes accomplished Iby going over the edge two or three times, but this, of course is optional. Y

Reference is now made to Figs. 6, 7, 8 and 9 which illustrates the use of the stropV 10 for stropping the two cutting edges 35 and 36 of a double edged blade 17. The

stropping of a double-edged blade 17 may be performed with a single strop 10 in Vexactly the same man-ner as above described for stropping la single edged blade 16 in which case one edge portion 37 of the blade 17 must be held in one hand while the other edge portion 38 of the blade is being stropped. The blade is then reversed and the stropped edge portion held in one hand while the unstropped edge portion of the Iblade is stropped. This mode of operation, however, involves a danger of getting cut by gripping one'ed-ge of the blade with the hand. Likewise, gripping an edge portion -between the fingers in this manner, after it'h'as been stropped, may impair the beneficial results -produced by stropping it. f

To avoid these difficulties in stropping a double-edged blade, the method of the present invention preferably employs two of the strops 10 in this operation. Fig. 6 shows two strops 10 applied to areas 39 and 40 of opposite edge portions 37 and 38 respectively of the blade 17 toward one end of `said blade so as to snugly grip Vsaid blade edge portions in said areas as shown in Fig. 8.

With the blade 17 gripped by said two strops, the pressure applied by one of the latter is increased above the pressure applied by the other of said strops and the strops are then pulled apart as shown in Fig. 9, inthe directions of arrowsl 41 and Y42 thus; causing the blade to remain gripped by the strop through which the greater pressure is applied and permitting the strop through which the lesser pressure is applied to slip from its clamping relation withv blade 17 at iight angles to edges 35 and 36 thereof, thereby erecting a stropping action on that edge portion of the blade lying. within the area which has been compressed between the stropping pads 11 ofV that strop. p

This operation is followed by allowing the strop 10, which was slipped from clamping relation with the blade, to expand as shown in Fig. '7 and then reapplying thispto grip another area 43 of the same edge portion of the blade. An excessive pressure is now applied through that strop to area 43 while a lesser pressure is applied to the area 39 by the strop on the other side of the blade, and the two strops are pulled apart. This will leave the blade gripped by pressure applied in area 43 while the blade edge embraced by the area 39 is stropped by the strop gripping this being pulled from clamping relation with the blade.V

This second stropping operation on double-edged bladev 17, just described, is followed by the reapplication of the left strop10 into gripping relation with the left bladeY cessive pressure being applied in the area 44 and a lesser pressure in the area 43 and the two strops pulled apart to perform a stroppiug operation in the area 43. Following this operation the right hand strop is reapplied to the right edge portion of the blade 17 to clamp the latter in the area 45. The blade is then gripped with an excessive pressure in the latter area and with a lesser pressure in area 44 and the two strops pulled apart stripping the left hand strop from the area 44 and effecting a stropping action in this area on the left blade edge 35.

The left hand strop 10 is now reapplied to the left blade edge portion to clamp the same in the area 46 with an excessive pressure and the right blade edge is clamped in area 45 with a lesser pressure while the strops are pulled apart to effect a stropping operation in area 45. The right hand strop 10 is now reapplied to grip the right edge of the blade 17 with an excessive pressure in the area 45, and a lesser pressure is applied through the other strop in the area 46 while the strops are pulled apart to effect a stropping operation in the area 46.

Both cutting edges 35 and 36 of double-edged blade 17 are now stropped and the blade ready for use in shaving.

The drawings illustrate the invention at a scale so that when the drawings are reduced in size in printing the patent, the patent will illustrate the invention correctly in full size scale.

It may be noted by observing the shape of the strop 1i) in Fig. 2, that this strop, when unconstrained, provides a mouth for receiving the cutting edge 21 of the razor blade 16 which is wide enough to permit considerable latitude in inserting said edge into said mouth without accidentally contacting the strop 10 with said cutting edge. Dotted line representations of the blade 16 in Fig. 2 illustrate this latitude. The width of said mouth is considered to be the distance which the surfaces of the stropping pads 11 are separated at the free ends of said pads. The depth of said mouth may be considered to be the distance which the blade 16 would extend into said mouth past the plane of the free ends of pads 11 if said blade were extended horizontally from the position in which it is shown in Fig. 2 until its edge 21 contacted the innermost point in said mouth. The length of said mouth may be considered as the outside dimension of the strop 19 measured along the axis of curvature of the middle element 12.

By reference to Figs. 2 or 7 it may be observed that, in the preferred embodiment of the invention here illustrated, the width of the U-shaped mouth formed by strop 1Q when the strop is free of constraint is almost as much as the depth of said mouth. Such a ratio between the width and depth of the mouth of the strop 10 is highly desirable, although the invention may be practically operated with a somewhat smaller ratio between the width and depth of said mouth. It is preferable, however, that the front opening of the mouth of the strop 19 have a width which is in excess of one-half the depth of said mouth, in order to prevent accidental collision between the cutting edge 21 and one of the pads 11 when inserting said edge between said pads.

lt is also to be noted in Fig. 2, that the inside radius of curvature of the middle element 12 is approximately onethird the depth of said mouth. This ratio is preferable and this radius should be in excess of at least one-fourth the depth of said mouth. 1t is also preferable that the pads 11 diverge from their points of union with said middle element when the strop 16 is not under constraint.

Attention is also called to the fact that the preferred embodiment of the invention shown in the drawings has an over-all width in the piane of the mouth opening thereof which is approximately equal to the over-all depth of the unit. While the strop of the invention is described as preferably made of soft rubber, the claims employing this term are understood to also embrace equivalent materials.

Use of the strop 10 of the present invention as above described has been found to reduce the skin cuts otherwise suffered in safety razor shaving approximately Such use also makes the razor cut the beard smoothly, closely and with practically no pulling, Its use furthermore doubles the number of shaves to be had from each blade as well as making all shaves uniformly excellent.

The claims are:

l. A method of strapping an edge of a safety razor blade which comprises the steps of interposing between the thumb and the forenger of one hand, a pair of soft sheet rubber pads, held in spaced relation and with said pads free to resiliently adapt themselves to the shape of said thumb and forenger when said pads are forced together and compressed between said thumb and forenger, inserting an edge portion of said safety razor blade between said spaced pads, pinching said pads and blade edge portion between said thumb and forenger to apply substantial compression to said blade edge portion only in the area thereof corresponding to the opposed areas in which said pads are pressurally engaged respectively by the tips of said thumb and 'forefingen withdrawing said blade from between said pads while so compressed, in a. direction at a right angle with said edge, and repeating said operation with successive fractions of said blade edge portion disposed within the compression area aforesaid, whereby the entire blade edge is stropped.

2. A method as in claim l in which a double-edged safety razor blade is stropped and in which the aforesaid method is applied concurrently by the respective thumbs and foreingers of two hands to the two edge portions of said razor blade and in which said blade is held tightly by the gripping of one edge portion thereof between one pair of said pads and thumb and forelinger of one hand, each time said stropping operation is performed on a fractional area of the other edge portion of said razor blade by the other hand.

3. A method as in claim 2 in which the successive fractional area stropping operations performed on one of the edges of said double-edged blade are interspersed alternately between the corresponding successive fractional area stropping operations performed on the other of said edges.

4. A safety razor blade strop comprising a pair of soft rubber stropping pads in iiat sheet form and means for uniting said pads along one side of said strop in widely spaced relation to form a relatively wide U-shaped mouth between said pads, the length of said mouth being substantially shorter than said safety razor blade, said pads being free to be pressed together between a thumb and a forelinger, while a razor blade extends between said pads, and to yieldably conform to the opposed tips of said thumb and forenger and transmit pressure to said razor blade confined substantially to the areas on said pads engaged by said tips of said thumb and 'forefinger, a stropping operation taking place when a Arazor blade, thus compressed, is withdrawn from between said pads in a direction at a right angle with the razor edge, a repetition of said operation on successive fractions of said edge being requisite to strop the entire edge.

5. A safety razor blade strop comprising an approximately U-shaped integrally molded soft rubber unit in which the opposite side elements of the U comprise stropping pads in flat sheet form and the middle connecting element of the U comprises a torque-providing integrating base which unites the stropping pads, and, when unconstrained, holds said pads in opposed spaced relation to provide a relatively wide mouth into which a razor blade may be inserted, edge first, with relatively small likelihood of a frontal collision between said edge and said strop, said base yielding when said pads are pinched between a thumb and foreiinger to cause said pads to swing inwardly and converge at a steep angle in their initial contact with said razor blade, said pads then yielding to further pressure 'from said thumb and forefor uniting said pads along one side of said strop whereby the resiliency of the material in said pads normally holds said pads, when unconstrained, in widely spaced relation defining a wide mouth between said pads into which the sharpened edge of a razor blade may be readily inserted in Ya direction at right angles with said edge and Without colliding'with said pads, said pads being free to be di- Y rectly engaged respectively by the thumb and forelinger of a hand and to be liexed inwardly by said engagement into compressing relation with said blade, said pads being immediately returned by said resiliency to said spaced relation upon the relaxing of pressure on said pads by said thumb and foreiinger.

7. A safety razor blade strop comprising a pair of soft rubber stropping'pads in at sheet form which are molded integrally with each other so as to be thus united along one side of said strop and normally held by said integral relation, when unconstrained, in widely spaced relation defining a wide mouth between said pads into which the sharpened edge of a razor blade may be readily inserted in a direction at right angles with said edge and without colliding with said pads, said pads being free to be directly engaged respectively by the thumb and foreinger of a hand and to be exed by said engagement into compressed relation with said blade, said pads being immediately returned, by the resiliency of the material of which they are molded and by their integral connection, to said normal spaced relation upon the relaxing of pressure upon said pads by said thumb and foreiinger.

8. A combination as in claim 7 in which said strop comprises an approximately U-shaped unit including a resilient sheet-form hinge element, opposite extremities of which are integrally united with said stropping pads, the wide mouth between said pads being substantially shorter than said razor edge, and having a front openn ing, the width of which is in excess of one-half the depth of said mouth.

9. A combination as in claim 7 in which said strop comprises an approximately U-shaped unit including a resilient sheet-form hinge element, opposite extremities of which are integrally united with said stropping pads, .the wide mouth between said pads, being substantially shorter than said razor edge, the inside radius of said hinge ele.

mentrbeing` in excess of one-quarter the depth of said mouth, saidY stropping pads diverging from their union with said hinge element, when not under constraint, to

facilitate said introduction of said blade edge therebetween.

10. A combination as in claim 7 in which said strop comprises an approximately U-shaped unit including a resilient sheet-form hinge element, opposite extremities.

of which are integrally united with said stroppingvpads',

the Vwide mouth between said pads being substantially shorter than said razor edge, the width of said unit in the plane of said mouth opening being approximately equal to the depth of said unit.

11. A strop as defined in claim 7 which, when compressed between tips of a thumb and foreiinger, with any portion of an edge of a double-edged safety razor blade held therebetween, transmits said compression from said thumb and foreiinger to a maximum of approximately one-third of said blade edge whereby, the withdrawal of said edge from between said pads in a direction at right angles to said edge, while said portion of said edge is thus compressed permits the stropping `of said one-third of said edge with the full compressive capacity of said thumb and foreinger applied solely to said one-third of said edge, said pads when released from pressure, immediately regaining their widely spaced relation whereby a different and unstropped portion of said blade edge may be inserted rapidly in the opposite direction between said pads, for continuing the operation of progressively stropping said edge, a fractional portion at atime.

References Citedlin the lile of this patent UNITED STATES PATENTS 609,516 Mack Aug. 23, 1898 932,536 Conrad Aug.'31, 1909 1,179,459 Kennedy Apr. 11, 1916 1,723,124 Bencze Aug. 6, 1929 2,629,211 Tierney Feb. 24, 1953

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