US2229971A - Dry shaving razor - Google Patents

Description

Jan. 2s, 19141. E, HAMMERUNG 2,229,971

DRY SHAVING RAZOR Filed Feb. 23. 12937 INVENTOR, Manuel Mlm/2h19,

- ,S ATTORNEYS Y til Patented Jan. 28, 1941 UNITED STATES PATENT OFFICE DRY SHAVING RAZOR manuel Hammerling, Cedarhurst, N. Y., assigner to American Safety Razor Corporation, Brooklyn. N. Y., a corporation of Virginia Application February 23, 1937, Serial No. 127,031 3 claims. (ci. sci-4,3)

This invention relates to dry shaving razors of the type comprising a rotary cutting blade.

An object of the invention is to produce a, dry shaving razor which is self-sharpening and has y the ability to automatically adjust itself to compensate for wear of the cooperating shearing parts of the same.

A further object of the invention is to produce a dry shaving safety razor in which uniform contact is assured between the shearing elements thereof.

A still further object of the invention is to provide a dry shaving razor which aiords full skin protection during the operation thereof and also one so constructed as to exert a skin tensioningeifect, thereby presenting the hair to the lll shearing elements of the razor in a substantially More specifically, the shearing edge on theI head may be produced by forming a slot longitudinally of the head communicating with the bore and grinding or forming a portion of the head extending along the cutting edge to produce a shearing edge of the desired thickness, such as is disclosed in iny co-pending application Serial provided at each end of the shearing edge by grinding the portion lof the head adjacent the. shearing edge. These extensions'aid in guiding the razor head along the skin and exert a skin tensioning effect to properly draw the hair into .w an erect position. The razor head may further include guard teeth, the free ends of which are spaced from the shearing edge by the slot.

The bore through the head of the razor is preferably of generally elliptical form, although sa it may be suitably made by grinding or drilling a cylindrical bore through the head and then grinding away a portion ofthe walls rof the head spaced from the shearing edge to produce curvatures of different radius in the bore.

as Mounted within the bore is a rotary cutter No. 97,895, filed August 26, 1936. Extensions are which may consist of a twisted or spiral blade having shearing edges on its longitudinal edgesto cooperate with the shearing edge on the head. Bearing members may be provided at the ends of 'the cutter blade of a diameter substantially 5 equal to the width of the blade. The diameter of the disks or bearing members is preferably such as to iit accurately in the cylindrical portion or the bore adjacent the shearing edge on the head, but to loosely iit the remainder oi' the 10 bore so that the cutter may move toward or away from the shearing edge. The comparatively large bearing surface area of the bearing disks or members results in a reduction of wear on these parts and in a reduction of wear on the shearing edges.

` In order to maintain the cutter blades in operative shearing engagement with the shearing edge on the head, resilient means may be provided for urging the entire cutter structure to- 2c ward the shearing edge and into the cylindrical portion of the bore.

The cutter is thus, in eilect, a free oatingw construction having no portions fixedly connected to the head, thereby allowing the cutter 2t to advance gradually as the ohead and the cutter blade wear, maintaining close engagement between them and tending to re-sharpen both the head shearing edge and the shearing edges of the cutter as they wear during operation.

Suitable means may also be provided for driv ing the iioating cutter construction from a motor preferably mounted in the handle of the razor.

For better understanding oi the present invention, reference may .be had to the accompanying drawing in which:

Figure l is a side elevation of a typical form of razor embodying the present invention;

Figure 2 is an end View of a typical form of cutter head embodying the present invention;

Figure 3 is a side view of the cutter head with an end plate removed to show the gearing for driving the cutter element;

Figure 4 is a side view of the opposite end of the razor with an end plate removed to disclose a typical form oi cutter advancing means;

Figure 5 is a sectional view oi. the razor taken' on line 5-5 of Figure 3.

Figure 6 is an enlarged sectional view taken on line 6-6401 Figure l; and i Figure 'l' is a sectional view, partly broken away, taken on line i--l of Figure -.4.

In the form of the invention disclosed in the drawing, the razor may consist of a handle member I0 containing'a rotary motor of any 55 suitable type and carrying at one end a cutter head E2.

The cutter head i2. may suitably consist of a block of metal i@ such as, for example, steel, of generally rectangular shape and having at one end a curved or arcuate surface iti. If desired, the arcuate end of the block id may be formed independently of the remainder of vthe bloei; and attached thereto in any desired manner. block it may be provided with a bore i5 eccentrically formed with respect to the curved surface i@ to produce a gradually decreasing thickness of metal toward the center of the arcuate surface i5. A shearing edge 2@ and guard teeth 2i of substantially the same thickness at their adjacent ends may be formed by slotting the metal iongitudinally oi' the curved surface it and then grinding down the arcuate surface i@ to provide comparatively thin edges adjacent the slot. Guard teeth 2i may be formed by slotting the metai in a plurality of planes perpendicular to the shearing edge 2i), thus providing a guard which will prevent the skin from passing inwardly of the shearing edge 20 but at the same time allowing whiskers to engage the shearing edge 25.

By grinding down the `outer cylinder surface I6, as best shown in Figures 2 and 6, shoulders 22 and 2d are formed at opposite ends of cutting edge 20. The shoulders 22 and 24 engage the skin, stretching it alongr the cutting edge. By stretching the skin, the whiskers are extended in an erect position against the shearing edge, allowing them to be severed close to the skin. Also, the vstretching action aids in preventing entry of the skin between the guard teeth 2I and into the slot between the shearing edge 20 and the free ends of the guard teeth 2 I v v The bore I8 is preferably of substantially cylindrical shape but is provided with an undercut portion which renders it somewhat elliptical in shape with its greatest diameter at an angle of about 60 to the shearing edge zo.

Mounted in the bore I8 is a cutter which may suitably consist of a spiral or twisted blade 26 of hardened steel having shearing edges 28 on its opposite longitudinal edges. stood that the cutter 26 may be provided with more than two shearing edges, if desired. The

i diameter of the cutter 26 from shearing edge to shearing edge is substantially equal to the smallest diameter of the bore I8, that is, within limits of manufacturing tolerances. The blade 26 is preferably given a left-hand twist in order that the severed hair will be directed from the left end of the cutter as viewed in Figure 5, toward -the right-hand end of the cutter, as it is rotated. The purpose of this construction will appear on further description of the construction.

Fixed to the opposite ends of the cutter blade 26 are disks 30 and 32 of a diameter equal to the diameter of the cutter blade from edge 28 to edge 28 and equal to the smallest diameter of the bore I8. The disks 30 and 32 form the bearings for the cutter blade and normally bear against the cylindrical surface of the bore I8 adjacent the cutting edge,` although the entire cutter assembly of blade 26 and disks 30 and 32 is capable of limited movement away from the shearing edge 20 because ofthe elliptical shape of the bore IB.

The cutter 26 and disks 30 and 32 construction thus is, in effect, a free floating construction which is not in a fixed coaxial relationship with respect to the shearing edge 26 or the bore I8.

The cutter assembly 25, 35 and 32 may be maintained in proper relationship to the shearing The It will be under-- edge Z5 of the-cutter head by resilient means norlly urgingthe cutter 25 outwardly and the disks t@ and t2 against the surface of the bore adjacent the shearing edge 2B. While any suitable means may be used for this purpose, I prefer toI use the construction best shown in Figures 4 and l consisting or an anti-friction bail 51B at each end of the cutter assembly and bearing against the disks 55 and 32. The balls may be mounted in suitable angularly arranged grooves 35 in opposite ends of the block ifi and are normally urged against the disks t@ and 32 by means of coil springs 3d. The grocves lie in the plane of the greatest diameter of the bore it. The ends of the head It arepreferably recessed, as best shown in Figure 5, to receive at one end the end plate fi@ for covering the ball 5t and spring E35, and at the opposite end for receiving gearing and a suitable cover plate F12 for covering the same.

The cutter y25 may be rotated by the rotary motor shaft it carrying a bevel gear is at its outer end. The bevel gear 55 meshes with a similarly beveled gear 48 carried onfa stub shaft 50 iournaled in a transverse bore in the head block It. The outer end of the shaft 50 may be provided with a spur gear 52- which, upon rotation, drives a third pinion 54 fixed to the disk 32 through an idler spur gear 56 mounted on stub shaft 58. The gear.54 and its drive gear 56 'l may be suitably ground so that a relative movement toward and from each other will not affect their driving relationship.

It will be seen from the foregoing description that the construction disclosed assures positive and uniform engagement between the shearing edges 28 of rotary cutter blade 26 and the shearing edge 20 on the cutter head. Also, the spring tension means will advance the entire cutter assembly as it and the cylinder surface of the bore I8 adjacent the shearing edge 20 wear away will prevent any of the severed hairs from being thrown into the train of gears 52, 54 vand 56. It will be understood from the foregoing that I have thus produced an effective and eiiicient dry shaving razor capable of long life without replacement of parts.

It will further be understood that many variations may be made in the specific construction thickness in said housing, two oppositely directed spiral shearing edges on said cutter cooperating with the edge of the blade to sever hair, means connected to one end of the cutter for rotating it, gearing and means to drive the gearing, torotate the cutter in such a direction as arrasar to sever hair and. cause the spiral edges to direct the severed hair away from said gearing.

2. In a dry shaving razor, the combination of a housing, a curved blade on said housing tapering in thickness to a longitudinal shearing edge, a longitudinal bore in said housing, a. rotatable cutter in said housing, oppositeiy directed helical shearing edgesn on said cutter, cooperating with the edge of the blade to sever hair, a hair discharge opening extending tangentially from the bore adjacent the shearing edge through the housing and means including gearing connected to one end of the cutter for rotating the cutter to sever and direct hair away from thegearing tl'iroh said discharge opening..

said shearingedge and a cover for said groove siidably mounted in said end.

HAMAERIJNG.

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