US2494464A - Rotary dry shaver - Google Patents

Description

Jan. 10, 1950 w. L. L. vlvlE ErAl. 2,494,464

ROTARY DRY SHAVER Filed May 4, 1946 manufacture.

Patented Jan. l0, 1950 UNITED STATES PATENT OFFICE ROTARY DRY SHAVER Conn., as trustee Application May 4, 1946, Serial No. 667,392 In the Netherlands January 13, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires January 13, 19.62

6 Claims.

This invention relates to a cutting plate for dry-shaving apparatus having a rotary cutting member, which cutting plate possesses an annular and apertured running surface for the cutting member which surface is supported both at the inner and outer edges. It is known in the dry shaver art that in shaving by means of dryshaving apparatus the hairs are cut more rapidly and shorter as the cutting plate is made thinner at the running surface of the cutting member. Although very small thicknesses of the material have been proposed theoretically for this purpose it has been found in practice that a deiinite limit cannot be exceeded in conjunction with reasonable conditions as regards solidity, life and For this reason the thickness of the cutting plate at the running surface amounts it about 0.08 mm. in commercial apparatus of the above-mentioned kind of shaving apparatus. The invention is based on the realisation that in satisfying the above-mentioned conditions the cutting plate may be made thinner locally if on the other hand strengthenings are provided at other points.

To this end, according to the invention, the inner edge of the running surface of a cutting plate, which has an annular apertured running surface for a rotary cutting member which surface is supported both at the inner and at the outer edges, is thinner than the outer edge.

An object of the invention is to make the annular running surface for the cutting member at the inner edge thinner and at the outer edge thicker than it has hitherto been customary in practice with such cutting plates. Since the running surface of these cutting plates generally bears at the outer edge on the housing of the shaving apparatus, and the support at the inner edge is constituted by a member of the cutting plate itself solely providing for the initial relation, for instance a plate-shaped or a cup-shaped part of the cutting plate with or without a bottom, a sufficiently solid construction of the cutting plate for permitting an inner part of the running surface which is thinner than normal is obtained by making use of the outer part of the running surface which is thicker than normal.

As a result of the use of a thinner annular central part of the cutting plate according to the invention the hairs may be cut shorter and more rapidly than by means of a conventional cutting plate of this type. In this case the thicker outer edge of the running surface acts as a rough shaving device, by which the hairs are cut somewhat shorter than by means of a normal cutting plate. However, this constitutes by no means a drawback, since it has been found in practice that when using the usual cutting plate having the same thickness throughout the hairs are not directly cut to a minimum length but stepwise to a smaller length in each instance.

The cutting plate of the present disclosure is preferably realized in such manner that the thickness of the running surface gradually varies from the outside to the inner side in a radial direction. Furthermore the invention is more partiularly of importance for4 the kind of cutting plate which is already known and in which the apertures of the running surface consists of slits extending from the inner to the outer edge. In this construction the material between the slits forms dams that are supported at both sides, it is true, but these dams are readily liable to sagging owing to their comparatively great length. When making use of the invention this drawback is avoided.

A suitable practical construction of the cutting plate according to the invention is obtained by giving the thickness of the running surface at the inner edge a value of less than about 0.08 mm. for instance 0.06 mm. and at the outer edge a value of more than 0.08 mm., for instance 0.11 mm.

Finally the use of the cutting plate according to the invention is of particular importance for those well-known shaving apparatus, in which the rotary cutting member is mounted with play both on the driving shaft and in the cutting head. In fact, it has been observed that such cutting members tend to rock, and that during rotation the cutting member bears in each instance solely on one and successively on a succeeding cutting arm of the cutting member. This action" of the cutting member with the ends of the cutting arms produces shock forces which often cause deterioration or bending of the cutting plate at the outer periphery. The invention sufficiently meets also this drawback.

The invention will be more fully explained by reference to the accompanying drawings schematically representing one embodiment thereof.

Figure 1 represents half a section of a cutting plate according to the invention and a cutting member cooperating therewith, Figure 2 being a bottom view of this cutting plate.

Figure 3 is a side view in sectional elevation of the annular cutting plate showing a stepwise variation of the axial thickness of the said plate.

Figure 4 is still another side view in sectional elevation of the cutting plate showing a constant axial thicknes'sat one annular portion of the said plate and, aj'comparatively rapidly decreasing thickness at another annular portion of the said plate.

Figure 5 is a further side view in sectional elevation of the cutting plate showing a gradual radial increase in thickness' of the said plate.

Figure 6 is an additional-side view in sectional elevation of the cutting plate, with a flat top surface showing a decrease in'thickness of the said plate at the inner side of the cutting head.

Referring to Figure 1, a cup-shaped cutting plate l is furnished with a central recess 2 and a number of slits 3 which, as isA shown in Fig. 2,` extend radiallir (3') or substantially radially` (3"), but generally from the central excavation to the outer edge. However, also other apertures may be used such as those shown, for inf stance, at 3V. The slits or apertures preferably open' in the central recess and in the outer wall of the "cutting plate. At the inner side of the cup-shaped cutting plate is provided an annular running surface 4 for a rotary cutting member 5. The running surface i is supported at the outer side by the cylindrical outer wall and at the inner side bythe wall of the central recess which yields the required stiffness. According tothe invention the thickness of the running surface at the inner edge 6 is smaller than at the outer edgev 'l in such manner that the thickness of the material at 6 is smaller and at greater than the normal thickness which is deemed admissible in the caseof a cutting plate having the same thickness throughout the active running surface. In-Fig. 1 use is made of a gradually varying thickness. l

Figures 3 to 6 representstill other forms of construction. In Figure 3 the decrease in thicknesstakes placeV stepwise. Figure 4 shows from the outside to the inner side at first a constant thickness followed by a .comparatively rapidly decreasing thickness and then a constant thickness again. In Figure 5 use ismade of a gradual decrease in thickness atboth sides of the cutting plate and in Figure 6 solely a decrease in thickness Aof the'running surface has taken place at the inner side of the cutting head.

What we claimI is:

l. Dry shaving apparatus, comprising an annular cup-shaped cutting plate'oand a rotary cut'- ting member, said platephaving an apertured annular running surface for the said member, said plate being` axially', thinner at the inner portion of the said running surface than at the outer portion of the said surface.

2. Dry shaving apparatus, comprising an annular cup-shaped cutting plate with a central recess and arotary cutting finer-uber, said plate having an apertured. .annular running surface for the said member, said plate axially decreasing in thickness in a uniform manner from the outside portion of the said surface to the inside portion of the said surface.

3. Dry shaving'apparatus, comprising an annular cup-shaped cutting plate and a rotary cutting member, said plate having an apertured annular running ysurface for the said member, said plate axially decreasing in thickness in a stepwise manner from the outside edge of the said surface to the inside edge of the said surface.

4. Dryshaving apparatus, comprising an annular cup-shaped `cutting plate with a central recess and a rotary cutting member, said plate having a radially apertured annular running surface for the saidmember, said plate axially varying in thicknessfrom the inside edge of the said surface to the outside edge of the ,saidsurface.

5. Dry shaving apparatus, comprising an annular cup-shaped cutting plate with a central recess and a rotary cutting member, said plate having an annular running surface with substantially radial aperturesy for the said member, said plate being axially thicker at one annular portion of the said runningv surface than at another annular portion.

6. Dry shaving apparatus, comprising an annular cup-shaped cutting plate with a central recess and a rotary cutting mem-ber, said vplate having an apertured annular. running surface for the said member, Vsaid plate vbeing axially thicker at the outside edge of the running surface than at the inside edge of thesaid. surface, the said cutting member beinggsupported at the edges of the said surface.

WILHELMUS LAMBERTUS LEONARDUS VIVIE. ALBERTUS VAN im LEE.

REFERENCES CITED The following referenceS. arcor record in the nie of this patent:

UNITED STATES PATENTS

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