US2312497A - Electric dry shaver - Google Patents

Description

March 2, 1943.

A. H. SOR E NSEN ELECTRIC DRY srmvn'n Filed June 20, 1938 INVENTOR LFREDH. SOQENSEA ATTORNEY Patented Mar. 2, 1943 UNITED STATES PATENT OFFICE ELECTRIC DRY SHAVER Alfred H. Sorensen, Detroit, Mich. Application June 20, 1938, Serial No. 214,620

Claims.

This invention relates to improvements in razors, particularly razors of the electric dry 1 shaver type.

Heretofore,.razors of the dry shaver type have employed stationary skin-engaging plates, variously termed shear plates, combing plates and so forth. These plates have been slotted or perness of metal, however thin that may be, and

be sheared off on the opposite side of that thickness of metal. It is true that some of the shear plates of the prior art have been extremely thin, so thin in fact as to necessitate internal bracing to prevent their collapse, but the fact remains .that in each and every instance a thickness of metal is interposed between the skin surface and the cutter. It is manifest that most, if not all, of the dry shavers of the prior art must be pressed closely against the skin surface to actually raise the skin surrounding the base of the hair to a level nearer the cutter in order to closely cut the hair. This practice often results in numerous tiny abrasions and cuts, and yet, if the shaver is not pressed closely to the skin surface, a satisfactory shave is not generally obtained.

One object of this invention is to provide a skin-engaging head which will permit the cutting or shearing elements of an internal movable cutter to cut or shear hairs as close to the base as desired. A further object is to provide a dry shaver which need not be pressed closely against the skin in order that a close shave may be obtained. It is also an object of the invention to provide a dry shaver with which the closeness 1 of the shave may be controlled by the operator by varying the angular positions in which the shaver is held in relation to the skin. The foremost object of this invention is the provision of a dry shaver in which the hairs come into direct con- 1 tact with the cutter without passing through a thickness of metal and with which the chances of cutting or abrading the skin are substantially eliminated.

In the accompanying drawing Figure 1 is an end elevation showing a portion of the operating mechanism for an oscillating cutter. Figure 2 is an elevation taken from the right side of Figure 1 with parts thereof broken away to illustrate the cooperating action of the cutter and I head. Figure 3 is an elevation similar to Figure 2 but with one half of the head removed. Figure 4 is an exploded view of the head and cutter. Figure 5 is a partial cross sectional view on line 5-5 of Figure 2 with cutter shown in neutral position. Figure 6 is similar to Figure 5 with the cutter shown in one cutting position. Figure 'l is a partial cross sectional view on line 'I--'l of Figure 2 with cutter shown in opposite cutting position.

Referring now to the drawing, in which like references indicate like parts, the head portion of a dry shaver is shown in Figure 1. The invention relates primarily to the head and cutter portions and accordingly, the usual plastic or metallic case is indicated merely by broken lines as at [0. Suffice it to say that the case 10 contains a source of motive power such as a small electric motor, to be controlled by the usual hand switch (not shown).

Located in the opening of the case is a head indicated generally at H. According to the preferred form of the invention, head ll comprises two complementary portions 12 and I3 which, in order to make the description easier to follow shall hereinafter be called the left head and right head respectively. These head portions may be held in the case In by any well known means. In Figure 1 the head is illustrated as being held against the shoulders M of the case by means of knurled set-screws l5, which also serve to maintain the left head 12 and right head I3 in assembled relationship. In addition, one or more dowel pins I6 serve to locate and hold one head portion with respect to the other. In Figure 5, dowel I6 is shown as being press-fitted within right head l3 and slip-fitted within left head I2.

The head I is provided with a cylindrical opening, one half of the opening being in each head portion. This cylindrical opening is finely machined to provide a bearing for a rotating or oscillating cutter. The cutter comprises a tubular sleeve H, which may be longitudinally split. The outer edges IQ of the split [8 are chamfered to remove the sharp edges. It will be understood that the sleeve ll, when unconfined, is of slightly larger diameter than the cylindrical opening 23 in the head. It follows that the sleeve I1 is .compressed slightly when inserted between the head portions I2 and I3 and that this compression will cause the sleeve wall to be in firm contact with the wall of the cylindrical opening 20. This radially outward pressure is desirable to keep the cutter sleeve in firm engagement with the cylindrical opening, but is insufficient to cause excessive friction.

Cutter I1 is provided with a series of very narrow slots or kerfs 2| and 22, arranged alternately as shown in Figure 3 and extending inwardly of the cutter sleeve I! nearly to the median line of the sleeve. The ends 23 of slots 2| and 22 are parallel and are very nearly normal to the walls of the sleeve H.

The lower or skin engaging end of the head Il may be rounded as indicated at 24 or may be any other suitable shape and is preferably flattened 01f as at 25. Left head I2 is provided with a series of fine kerfs 26 extending horizontally as shown in the several figures. There kerfs 26 and the metal between each of them are approximately the width of an average hair. Right head I3 is likewise provided with a series of kerfs 21, disposed oppositely to kerfs 26 in left head l2. It will be understood that the metal between one of the kerfs 26 will be disposed opposite one of the kerfs 21. Kerfs 26 and 21 might be termed combing slots. Kerfs 2| and 22 in the cutter l1 and the thicknesses of metal between them are of the same width as the kerfs 26 and 21 in the head Kerfs 2| are in alignment with kerfs 26 and kerfs 22 are in alignment with kerfs 21. The ends 23a of kerfs 2| coact with the sharp edges of the metal between kerfs 21 to shear hairs guided toward the shearing point by kerfs 26, and conversely ends 231) of kerfs 22 coact. with the sharp edges of the metal between kerfs 26 toshear hairs guided toward the shearing point by kerfs 21. It will be seen in Figure 4, an exploded view, that by grinding or honing the bottom surfaces of the thicknesses of metal lying between kerfs 26 and 21 to form the flattened portion 25, the edges of these thicknesses of metal may be made extremely sharp, and that a hair brought into engagement with one of these sharp edges will be sheared by the cutter substantially at its base. Figure 6 shows the end 2311 of one of the kerfs 2| immediately after it has been rotated past the edge of one of the thicknesses of metal between kerfs 21, and Figure 7 shows one of the alternate ends 23b immediately after it has been rotated pastthe edge of one of the thicknesses of metal between kerfs 26.

Figures 1 through 4 illustrate one type of mechanism which may be used to impart an oscillating movement to the cutter IT. A pair of crank arms 28, joined by a cross-head 29, are pivoted as at 30 to depending legs 3| which form a part of the motor mounting inside case I. The lower end of each crank arm 28 is slotted as at 32 to receive a headed stud or rivet 33 at the end of a crank arm 34, one of which is disposed at each end of the cutter sleeve ll. A shaft 35 leading from the motor (not shown) has an oifset portion 36 projecting through a slot 31 in a flange 38 of the cross-head 29. It will be seen that rotary movement of shaft 35 will be translated into oscillating movement of the cutter sleeve IT by means of the mechanism just described. The range of oscillation is illustrated by Figures 6 and '7, and amounts to approximately 120 degrees.

In the dry shaver illustrated and described the closeness of the cut may be controlled by the operator. lating type of cutter the shaver may be moved in two directions in its shaving operation. The closest shave will be obtained by holding the shaver normal to the skin surface and if the operator wishes to cut the hairs a little less closely to the skin surface, the shaver may be held at a slight angle to the normal position. This causes the shearing point to move slightly away from the skin surface, moving about somepoint on the lower end of curve 24 or the flat as afulcrum.

By virtue of the sharpness of the stationary cutting edges, hair may be sheared as closato the base as desired. Itwill be seen that each hair is sheared off on the opposite side of a very sharp, razor-thin edge. This edge could hardly be called a thickness of metal. 7

I claim:

It is obvious that in using an oscil- 7 1. A dry shaver comprising, in combination, a head consisting of complemental head portions each having a cutting edge, and a cutter having an oscillating movement within said head, said 5 cutter being a split sleeve having two series of kerfs cut therein, the ends of the kerfs being substantially normal to the wall of the sleeve,

. said kerf ends forming cutting edges disposed on each side of the split and spaced therefrom, the two series of cutting edges on said cutter sleeve being respectively adapted to coact with the cutting edges in said head portions.

2. A dry shaver comprising, in combination, a head having a plurality of cutting edges and a cutter having an oscillating movement within said head, said cutter being a split sleeve and having two series of kerfs cuttherein the ends of the kerfs being substantially normal to the wall of the sleeve, said kerf ends forming cutting edges disposed on each side of the split and spaced therefrom, the two series of cutting edges on said cutter sleeve being respectively positioned to coact with the cutting edges in said head.

3. A dry shaver comprising, in combination, a head having a plurality of cutting edges and a cutter having an oscillating movement within said head, said cutter being a split sleeve and having two series of kerfs cut therein the ends of the kerfs being substantially normal to the wall of the sleeve, said kerf ends forming cutting edges disposed on each side of the split and spaced therefrom, the two series of cutting edges on said cutter sleeve being respectively positioned to coact with the cutting edges in said head, said outter sleeve having a yielding frictional engagement with said head.

4. A dry shaver comprising, in combination, a head consisting of complemental head portions each having a series of alternately positioned cut- 40 ting edges and combing slots in one end thereof arranged with the combing slots in each head portion opposite the cutting edges in the other head portion and adapted to guide hairs thereto and an oscillating cutter within said head, said cutter being a split sleeve having a series of slotted cutting edges on each side of the split and spaced therefrom, one seriesof cutting edges in said cutter being adapted during one movement of the cutter to coact with the cutting edges in one of said head portions'and the other series of cutting edges in said cutter being adapted during the reverse movement of said cutter to coact with the cutting edges in the other of said head portions.

5. A dry shaver comprising, in combination, a head consisting of complemental head portions each having a series of alternately positioned cutting edges and combing slots in one end thereof arranged with the combing slots in each head portion opposite the cutting edges in the other head portion and adapted to guide hairs thereto and an oscillating cutterwithin said headJsaid cutter being a split sleeve having a series of slotted cutting edges on each side of the split and spaced therefrom, one series of cutting ."ed'gesin said cutter being adapted during one movement of the cutter to, coact with the cutting edges in one of said head portions and the other series of cutting edges in said cutter bein adapted durin the reverse movement of said cutter to coact with the cutting edges in the other of saidhead portions, said cutter having a yielding frictional engagement within said head.

ED ii. sesessss.

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