US2298962A - Dry shaver - Google Patents

Description

Oct. 1942- T. J. MURPHY 2,298,962

DRY SHAVER Filed May 10, 1939 mYENToR ATTORNEYE,

Patented Oct. 13,, 1942 UNITED STATES PATENT OFFICE DRY SHAVER Thomas J. Murphy, Stamford, Conn.

Application May 10, 1939, Serial No. 272,807 2 Claims. (01. 30-43) This invention relates to dry shaving devices, and has for an object to provide an improved and simplified dry shaver construction which will operate more effectively and efficiently to rapidly cut the hairs close to the skin without injuring or irritating the skin, and also to provide a construction to facilitate manufacturing and such that the device may be manufactured at less cost and with fewer operations.

With the foregoing and other objects in view I have devised an improved construction as illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood that I am not limited to the specific details shown but may employ various changes and modifications within the scope of the invention.

In the drawing:

Fig. 1 is a top plan view of a dry shaver cutting head constructed according to my invention with a portion broken away;

Fig. 2 is a partial side elevation and a partial section of the same;

Fig. 3 is a bottom plan View;

Fig. 4 is an exploded view of one end portion thereof showing the parts in separated relation;

Fig. 5 is an end view;

Fig. 6 is a top plan view of one end portion of the outer or guard elements on an enlarged scale;

Fig. '7 is a transverse section thereof through the upper portion of these outer or guard elements only;

Fig. 8 is a top plan view of one end portion of the inner or movable cutter on an enlarged scale;

Fig. 9 is an edge view looking toward the inner end of one set of the teeth, the view being substantially on the line 99 of Fig. 8;

Fig. 10 is a partial side elevation and partial section of one end portion of a modified construction;

Fig. 11 is an end view thereof;

Fig. 12 is a perspective exploded view of one end portion of this modified construction;

Figs. 13, 14 and 15 are an end view, elevation of one end portion, and a top plan view of one end portion respectively of another modified con struction; and

Fig. 16 is a top plan view on an enlarged scale of a few of the outer guard teeth showing the finishing operation.

This invention relates to the cutter head which is removably mounted in a body and handle so that the head may be passed over theskin during the shaving operation, and which body contains a suitable electrical operating mechanism for reciprocating the movable cutter such for example as the mechanism disclosed in my prior application 250,349, filed January 11, 1939.

Referring first to Figs. 1 to 9 inclusive, the head comprises a central block I secured to the opposite sides of which are plates 2 and 3. These plates as shown in Figs. 4 and 5 are wider than the width of the block I so as to extend beyond the upper surface thereof, and at their upper edges are provided with inwardly extending flange portions 4 and 5 respectively. The edges of these flange portions, however, do not come together but are separated by a longitudinal slot 6. In the present showing one flange only, that is the flange 4, is provided with a series of spaced guard and cutter teeth 1 extending in a direction transversely of the slot 6 and the flange 4 and having their inner ends at one edge of the slot 6. The other flange 5 is plain and has no teeth and thus has a plain edge 8 forming the other edge of the slot 6 and opposed to the teeth I. At its opposite ends the flange 4 has somewhat raised or thicker portions or bosses 9 to engage the surface of the skin to prevent the teeth 1 from digging in or irritating the skin. The central portion between these bosses and therefore the teeth I has to be ground thin enough for close shaving. The opposite plain flange 5 is substantially the thickness of the bosses 9 so that at its intermediate portion the outer surface of this flange is a short distance outwardly of the outer surfaces of the teeth 1. The width of the two flanges 4 and 5, however, are substantially the same so that the slot 6 and the cutting edges are substantially in the center of the skin contacting edge or face of the cutter head or body to give the best operation. Otherwise it does not operate as satisfactory as the angle of the skin contracting surface on the face is always changing. The plain or dead side 5 is relatively wide and the cutting edge being substantially central with activation helps to keep the device in the proper position and at the proper angle. With this arrangement the surface of the plain flange 5 engages the skin as the contacting face of the head is passed over the surface of the skin and acts as a guide and positioning means to position the teeth 1 at the proper angle and relation to the surface of the skin for the best shaving operation, so that the teeth are not too steeply inclined so that the points or ends dig into the skin to irritate it,

or too steeply inclined in the opposite direction to raise them above the surface of the skin so as not to get the proper shaving effect.

The thickness of the flange 4 at the ends through the bosses 9 is preferably about .015". The free ends of teeth 1 are preferably about .003" with the angle of the inner end Ia of the space between the teeth at an angle of about 4 to the horizontal. The width of the free ends of the teeth may be about .012 with the space between the teeth about the same. The plain flange 5 is preferably about the same thickness as the bosses 9, or that is about .015", and therefore the outer or skin contacting surface of flange 5 is somewhat above the outer surfaces of teeth I. The free edge 5a of flange 5 is also rounded so as not to irritate the skin and to prevent discomfort when moved against stubble of beard. It will of course be understood I am not limited to these dimensions but these have been found to be very satisfactory.

The two plates 2 and 3 may be secured to the block I by any suitable means but preferably they are clamped tightly against the opposite side surfaces of the block I and soldered thereto by solder supplied to the contacting surfaces. Thus the block accurately spaces and relatively locates the two plates 2 and 3 and their flange portions. To facilitate the soldering the block I may be provided with suitable recesses or notches III in their side edges which are also preferably tapered as shown so as to carry the solder to the adjacent surfaces of the block and the plates.

Mounted within the body of this head between the projecting portions of the side plates 2 and 3 and between the flanges 4 and 5 and the top of the block is a longitudinal reciprocable cutter II. This is of substantially rectangular cross section having a bottom wall I2 and side walls I3. At the upper edges of the side walls are two rows of spaced cutter teeth I4 projecting inwardly toward each other in opposed relation as shown. These teeth extend in a direction transversely of the slot 5 and their free ends are separated by a similar longitudinal slot I5 in alignment with the slot 6. The top surfaces of these teeth are inclined at the same angle as inner surfaces I5 and II of the teeth I and flange 5 respectively which is preferably about to the horizontal, and when the cutter is in position in the head the top surfaces of these teeth engage the inner surfaces of the flanges 4 and 5 as shown in Fig. 5. Also, as shown in this figure the free ends of the teeth I and the edge 8 of the flange 5 project slightly beyond the free edge of the cutter teeth I4 to prevent these teeth irritating the skin. It is preferred that the outer teeth I overhanging the inner teeth about .004" or .005" to permit rounding and buffing of ends of the outer teeth so that when completed they will project slightly over the inner teeth. The free edge of plain flange 5 also overhangs the free ends of cutter teeth I4 under this flange. The teeth I4 cooperate with the teeth I for the cutting and shaving operation and it is preferred that the pitch or spacing between the teeth I4 be slightly different from the pitch or spacing of the teeth I so that as the cutter reciprocates the teeth do not all reach their cutting position with respect to the teeth 'I at the same time so that the cutter teeth I4 and the guard and cutting teeth I perform their shearing operations in succession thus reducing the power required for operation of the cutter. Preferably the width of teeth I4 at their face is about .010" and the space between the teeth .020".

It is not necessary to have two sets of cutting teeth on the reciprocating cutter II as there is only one set of stationary guard and cutting teeth I on the skin contacting face of the head, but it is preferred to use two sets of cutter teeth I4 as shown and to make the cutter reversible so that should one set of cutter teeth I4 become dulled while cooperating with the guard teeth I the movable cutter may be reversed to bring the other set of teeth I4 into operative cutting position under the teeth I and the dulled teeth placed under the inoperative side of flange 5. During operation of the cutter there is a sort of burnishing operation between the outer faces of the inactive teeth engaging the inner surface II of the plain flange 5 which sharpens these teeth restoring their cutting edges preparatory to again being used as the active cutting teeth in cooperation with the teeth 'I.

For reciprocable operation of the cutter I I the block I is provided with an elongated opening I8 through which projects an operating pin I9 from the electrical operating mechanism, not shown, the upper end of this pin being tapered and rounded as indicated to seat in the rounded transverse recess 20 in the lower wall I2 of the reciprocable cutter. This recess may be formed by pressing up the wall of the cutter as indicated at 2I before hardening. The outer side surfaces of side walls I3 may be relieved as shown at I30. to reduce the friction surfaces between this element and the sides 2 and 3 leaving narrow bearing surfaces I3b.

Figs. 10, 11 and 12 show a somewhat modified construction. In this construction the body comprises a central block 22 and side plates 23 and 24 corresponding to the block I and side plates 2 and 3 of the first form, but while the block 22 is the same as the block I plates 23 and 24 are somewhat wider than the plates 2 and 3 so as to project somewhat further beyond the top surface of the block 22 to accommodate a somewhat different construction of movable cutter. The upper edges of the plates 23 and 24 are however formed the same as the upper edges of the plates 2 and 3, that is, the plate 23 is provided with stationary guard or cutter teeth I and the bosses 9 while the plate 24 has the same plain flange as the plate 3. Located at the inner surfaces of these flange portions are the two sets of movable cutter teeth I4 the same as in the first form, but these teeth instead of being on an integral one-piece cutter as shown in Figs. 4 and 5 are formed on the side plates 25 of a cutter constructed similarly to the body. That is this cutter comprises a central block 26 to the opposite sides of which the plates 25 are secured, preferably by clamping them to the sides of the block 25 and soldering them to the surfaces of this block, the same as the plates 2 and 3 are soldered to the block I and the plates '23 and 24 are soldered to the block 22. In a similar manner the sides of the block 26 are provided with tapered recesses 21 to carry the solder to the contacting surfaces the same as the tapered recesses III in the sides of the blocks I and 22. For operating this cutter the block 22 is provided withan elongated opening 28 for the operating pin 29 connected to the electrical operating device and seated at its end in a suitably shaped recess 30 in the bottom wall of the block 26. The relation of the flange 4, teeth I and flange 5 with respect to the cutter teeth I4 in this construction is the same as described in connection with the first form. To decrease the bearing surfaces between the plates 25 and the plates 23 and 24 the outer surfaces of the plates 25 may be cut away as shown at 3| leaving longitudinally extending narrow bearing surfaces 32 to thus reduce the frictional contact'between the plates. Also, as shown in the prior application mentioned a spring tends to force the pins l9 and 29 against the movable cutters so as to press the movable cutter teeth I4 against the inner surfaces of the teeth I and flange 5 to retain the proper cutting relation.

A still further modification is shown in Figs. 13, 14 and 15. It will be seen from Figs. 4 and 11 that the top surface of the flange 4 and the cutter teeth I is lower than the top surface of the bosses 9 at the opposite ends of the flange 4. This requires a comparatively expensive grinding operation and therefore I have devised a construction shown in Figs. 13, 14 and 15 to secure the effect of the raised bosses 9 but eliminating or reducing the expensive grinding operation. In this construction the body comprises the central block 33 corresponding to the blocks I and 22 of the other form to the opposite sides of which are soldered the side plates 34 and 35 corresponding to plates 2 and 3, and 23 and 24. The flange 36, however, at the top edge of the plate 34 on which are formed the stationary guard and cutter teeth 31, is made of the same thickness throughout the length of the plate eliminating the raised bosses 9 as used in the first form. However, to secure the guiding and protective effect of these raised flanges a ferrule 38 is placed about the block 33 and side plates 34 and 35 with the proper thickness so that its top surface at 39 is located at the proper height above the surface of the flange 36 to correspond with the top surfaces of the bosses 9. However, as the plain flange 40 on the top edge of the plate 35 is thicker than the flange 36 the end portions of this flange 40 are reduced or recessed the proper amount as indicated at 4| to receive the band or ferrule 38 to located its top or skin contacting surface substantially on the same level of the skin contacting surface of the flange 40. With this construction the stock for the side members 34 and 35 can be rolled or drawn in great lengths almost to finished dimensions with a corresponding saving in cost. These ferrules 38 at the opposite opposite ends of the head may be pressed over the ends and secured by soldering them to the bottom of the block 33 and also to the plates 34 and 35. To prevent the ferrule when applied forcing inwardly the upper edges of the flanges 36 and! to bring them too close together the ferrule may be provided with a short downwardly extending lug or lip 42 projecting downwardly between the flanges 36 and 40 as shown so as to keep these flanges in proper spaced relation and prevent the teeth springing together when the ferrule is pressed on the ends of the head. The ferrules may be of steel of about .015" or .020" thick by wide. Cooperating with the teeth 31 and the flange 46 is the cutter 43 which may have the same two sets of teeth I4 as provided on the cutter in the first two forms. This cutter may be constructed as shown in Fig. 4 or it may have the construction of Figs. 11 and 12.

It will be seen that this cutter head is very simple in construction involving a minimum number of parts. As the plates 2, 3, 23, 24, 34 and 35 are formed separately from the mounting block they are much easier to manufacture and finish and may be made at much less cost. It is also much easier to properly shape and finish the teeth 1 than would be the case if the body of the head was formed in one piece. As shown in Fig. 16 a simple and effective way of finishing the teeth 1 is by using an angularly shaped fine stone or abrasive element 44 to remove the sharp corners 45 of the teeth as indicated at 46, and then by bufling the ends of the teeth are rounded and given a substantially half-round shape as shown at 41 eliminating sharp corners which might dig into or irritate the skin and cause discomfort.

Having thus set forth the nature of my invention, what I claim is:

1. In a hair cutting deviceof the character described, a cutter head comprising a mounting block, plates secured to the opposite side faces of the block and extending beyond the top edge thereof, the upper edges of the plates being extended inwardly toward each other and inclined backwardly in opposite directions forming flanges having substantially flat oppositely inclined outer surfaces to engage the surface of the skin and with the free edges of these flanges separated by a central longitudinal slot, one of these flanges being plain to form a guiding surface on the skin and the other flange including a set of spaced guard and cutter teeth extending in a direction transversely of the slot with their free ends forming one edge thereof, and a longitudinally reciprocable cutter mounted between the plates on said block and having a row of spaced cutter teeth extending in a direction transversely of the slot with their free ends at the edge of the slot and located back of the first teeth to cooperate therewith.

2. A hair cutter of the character described comprising a central block, plates secured to the opposite sides of said block and extending beyond the top surface thereof, the upper edge portions of said plates being extended inwardly toward each other to form flange portions with their edges separated by a longitudinal slot, one of said flanges being provided with a series of spaced guard and cutting teeth extending in a direction transversely of the slot and with their free ends at the edge of the slot, a ferrule embracing the plates at each end thereof and extending above the top surface of the teeth to provide skin engaging surfaces, a lug on each ferrule extending into. the slot between the free edges of the flanges and of substantially the width of the slot to maintain the edges in spaced relation, and a longitudinally reciprocable cutter mounted between the plates and having a' row of spaced similarly arranged teeth in back of the first series of teeth to cooperate therewith.

THOMAS J. MURPHY.

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