US2182066A - Electric shaver and shearing blade therefor - Google Patents

Description

Dec. 5, 1939. J. BRUECKER ELECTRIC SHAVER AND SHEARING BLADE THEREFOR Filed May 20, 1937 3 Sheets-Sheet 1 a 1 0 MEV/g w 7 7 Z J ao f4.0@ a@ Z 6 af@ WJ a J Ln M w .t o Z2 3 j z n 3% .y 7

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ELECTRIC SHAVER AND SHEARING BLADE THEREFOR Filed ay 20 1937 3 sheets-sheet 2 JJ ff Mmm Patented Dec. 5, 11939 UNITED STATES ELECTRIC SHAVER AND SHEARING BLADE THEREFOR John Bruecker, Chicago, Ill.

Application May 20, 1937, Serial No. 143,754

5 Claims.

This application is a continuation in part of my application Serial No. 98,541, led August 29, 1936 on which Patent No. 2,081,694. was granted May 25, 1937, and relates to what is known as a dry shaver for removing Vbeards or face hair without the use of lather and similar preparations.

The shaver of my invention is characterized by the combination of a cutter to which a very rapid movement is imparted and a shearing blade of a cutting head, which shearing blade is perforated and of extreme thinness, so that the rap idly traveling cutter produces a shearing action on the minute particles of hair projecting through the perforations of the extremely thin shearing blade when the latter is pressed against the face. In the preferred form of my invention the cutter is Oscillated in an arc conforming. with that of the shearing blade, and is so supported during its rapid movement as to be urged into engagement with the inner face of the shearing blade, for which purpose the cutter is free to move outwardly under centrifugal action against the shearing blade or maybe pressed against the same by a spring or the like. This novel combination as claimed in my prior application provides for greater efficiency in the shaving operation. u I,

One of the objects of the presentvinvention is to provide an improved operating relation between the rapidly oscillating cutter and the thin, perforated shearing blade, whereby to avoid any possibility of uncut hairs being caught by the cutter at either end of its movement. To this end I have made a new .arrangement of the closely positioned hair-receiving perforations in the arcuate portion of the shearing blade by conning them to a different given zone and providing an imperforate area contiguous to each end of the perforated zone,'and I havefurther provided for operation of the cutterin -anarc so related to the said perforated Azone that when the cutter comes to rest momentarily at each end of the oscillating stroke it will be wholly in engagement with the imperforate area at such end. According to my ,invention the portion of the cutter which engages the inner side of the shearing blade is disposed outside of the closely perforated area and inside of the imperforate area at each end of the oscillating stroke and avoids any tendency of uncut hairs becoming engaged between the perforations and the cutter and thereby being momentarily pulled by motion of the shaver over the face. In the preferred form this unperforated portion is disposed between the hair-receivingperforations and perforations for the discharge of cut hair from the interior of the cutting head.

Another object is to provide an improved cutting head or shearing blade adapted for use in 5 a dry shaver of the character described.

Another object is to provide improved methods of manufacturing shearing blades suitable for use in a dry shaver, whereby to effect economies in the cost of manufacture and to provide a more 10 eflicient and satisfactory shearing blade for the purpose intended.

Other objects and attendant advantages will be appreciated by those skilled in this art as the invention becomes better understood by referi5 ence to the following description when accompanied by the following drawings, in which- Figure 1 is a longitudinal section through the cutting head end of a shaver embodying my invention;

Fig. 2 is a section taken substantially on the section line 2--2- of Figure 1;

Fig. 3 is a plan view of one embodiment of the thin shearing blade which forms the cutting head, one end of the blade being broken away; 25

Fig. 4 is an enlarged plan or face view of the perforated portion of said shearing blade;l

Figs. 5 and 6 are detail sectional views showing the manner in which the slots are formed in the central portion of said shearing blade;

"Figs. 7, 8, 9 and-10 are enlarged plan views of the face of a shearing blade in connection with different methods of making the same according to my invention;

Figs. 11, l2, 13 and 14 are vertical sections 35 corresponding with Figs. 7, 8, 9 and 10, respectively, illustrating the die action in forming the perforations;

Fig. l5 is a somewhat diagrammatic view showing the step of lapping the shearing face 40 ofthe blade according to my invention;

Fig. 16 is an enlarged detail section crosswise of one of the perforations after the lapping operation, with the blade exed to the curvature which it occupies in actual operation;

Fig. 17 is a somewhat diagrammatic View showing a shearing blade of the kind illustrated in Fig. 10 supported in an operative position in the shaver, the radius being larger than that of the lapping tool;

Fig. 18 is an renlarged detail section crosswise through one oi the perforations of the shearing blade in its operative position shown in Fig. 17, as for example, taken on the section line |8l8 of Fig. 10;

Fig. 19 is a plan view of the face of a shearing blade of a modified form, embodying my invention;

Fig. 20 is a somewhat diagrammatic view illustrating a step in the operation of forming the blade shown in Fig. 19;

Fig. 21 is an enlarged detail plan view of a perforated portion of the blade shown in Fig. 19;

Fig. 22 is a section takenwon the section line 22-22 of Fig. 21, and

Figs. 23 and 24 illustrate additional forms of punching operations in the manufacture of a cutting head according to my invention.

My improved shaver is adapted to be embodied in a small hand unit for convenient manipula.- tion, which preferably but not necessarily includes an electric motor or the equivalent for operating the cutter. In the present application I have omitted the motor end of the unit and have shown only the cutting head end.

Referring to Figs. 1 and 2, the cutting head or shearing blade designated generally by the -reference numeral 24 is of extremely thin exible material, such, for example, as a strip of spring steel of approximately .003" in thickness having closely positioned perforations or hair-receiving openings 25 throughout a medial area 26. The cutting head when removed is normally at, as shown in Fig. 3. By flexing the cutting head medially to the semi-cylindrical form shown in Figure l, the fiat end portions 21 may be inserted through narrow slot-like openings 28 in the hous ing to the operative position here shown. In this position, the marginal portions 29 along the longitudinal edges of the cutting head seat against semi-circular shoulders 30 formed on a suitable support or bracket having end walls 3| and side walls 32. Suitable means, such as spring holding elements 33, enter openings 34 in the cutting head and exert a downward pull to hold the marginal portions 29 rmly seated against the stationary shoulders 30 and with the perforated portion in the flexed or semi-cylindrical shape shown. The bracket is fixed within a s'uitable housing designated generally by 35. Each spring element 33 is part of a coil spring 36 carried on a post 31 extending between opposite walls of the housing 35, the spring elements being constantly urged inwardly and downwardly to pull the cutting head down to its working position. Suitable means such a key not shown here but disclosed in my prior application may be provided for. spreading the spring elements 33 and withdrawing them from the cutting head so that the latter is free to be removed through the openings 28. It will be apparent that the user may grasp the projecting cutting head between the fingers and remove it bodily. 'This is desired for the purpose of replacing the cutting head when it becomes worn, or for changing blades and also for giving access to the cutter for inspection and replacement. 'I'he cutting head may be replaced by repeating the operation, the key being removed or withdrawn after the cutting head is in the working position, thereby permitting the spring elements to engage the end portions of the blade to hold the blade firmly against the seats 30.

The cutter 38, preferably of steel or a suitable alloy, is in the form of a thin at blade `and extends lengthwise from end to end of the cutting head as shown in Fig. 2. The cutter is carried by a rock-bar 39 mounted to oscillate on suitable bearings 40, in this instance carried by the end walls of the bracket. In the preferred form, the

axis about which the rock-bar oscillates is coaxial with the semi-cylindrical perforated portion of the cutting head. The rock-bar is suitably slotted or shaped to receive the cutter so that the latter is free to move bodily outwardly under centrifugal force when the rock-bar is engagement with the inner face of the cutting head from end to end of the cutter. The cutter is oscillated at a comparatively high speed by suitable power means. This may be done in many ways from a power driven shaft, but I prefer to employ a small electric motor contained within the handle portion of the shaver as above mentioned and suitably arranged to impart rotary motion at a high speed to the shaft 42. This shaft is equipped with a disk 43 which carries an eccentric pin equipped with a ball 44 disposed between parallel plates 45 xed to the rock-bar. By this means the cutter will be oscillated at a high speed, in this instance, through an arc indicated by the dotted line positions of the cutter, Fig. 1. The pressure of the cutter against the inner face of the cutting head will be uniformly distributed from end to end of the cutter, and the cutting edge will be constantly urged against the extremely thin cutting head so as to provide intimate shearing engagement between the edge of the cutter and the numerous cutting edges formed by the perforations in the cutting head. Inthe form here shown the cutter is mounted so that it is free to have ka tilting movement upon and with respect to the rock-bar at the end of each stroke, as upon the fulcrum faces 46, for reasons explained in my prior application; but it will be manifest that this pronounced tilting action is not essential. In the commercial practice of my invention the cutter is mounted in a radial position with respect to the rock-bar and has sufficient play therein to permit of the desired bodily movement under centrlfugal action or spring pressure, or both, as hereinabove described.

'I'he hair-receiving openings 25 are confined to the zone 26 above mentioned which is shorter in length than the travel of the cutter at its outer end. Thus the cutter at each end of its stroke cornes to rest at an imperforate area 41 and thereby avoids any danger of uncut hairs being caught between the cutter and the cutting head at this stage of the operation. I prefer to employ a series of openings 48 in the cutting head just beyond each imperforate area 41 for the discharge of cut hair.

' In the embodiment of my invention shown in Figs. 3 to 6 inclusive, the medial portion of the cutting head or shearing blade is provided with a plurality of series of hair-receiving openings in the form of slots. 'I'hese series of slots extend from one edge of the medial portion to the other and are arranged at an angle of approximately 10 with respect to the end edges. As shown in Figs. 3.and 4, the slots of one series are staggered with respect to the slots of the contiguous series. The slots are formed by placing the cutting head forming strip between a pair of dies, one of which embodies a plurality of ribs corresponding in number and design to the slots, and the other of which embodies a plurality of recesses for receiving the ribs of what may be nsv together with the cutting head forming stripl therebetween, the ribs of the male die deflect the metal of the strip so that the latter has indentations 49 on one side thereof and projections 50 on the other side. The ribs on the male die are greater in height than the strip is thick with the result that the indentations in the one side of the strip, that is, the skin-engaging face, are of greater depth than the strip. After the strip' has been subjected to the action of the dies, the projections 50 on the inner face of the strip are ground olf or reduced, with the result that the slots 25, referred to above as hair-receiving openings, are formed. Because .of the specific manner in which the slots are formed, the cutting head has on the outer face thereof a plurality of series of cavities or indentations 49, and embodies on its inner face cutting edges I. The latter define the slots and are flush with the inner face of the cutting head. When the cutting head is moved over the skin for shaving or hair depilation purposes, the skin works its way into the cavities and the hairs when they encounter the slots, snap or work their way through the slots. Because of the cavities and the manner in which they operate to receive the skin, the cutting edges 5| are aligned w'lth the hairs at the points at which they protrude from the skin. As a result of this, the blade type cutter 38 when it is oscillated within the cutting head as above described, effects an extremely close cutting of the hairs. 'I'he cavities 49 are dished and serve to direct the hair through the slots. The slots are the same in length, as shown in Fig. 3, and each slot is placed from the adjoining slots of its series a distance slightly less than the slots length. As a result of this, and because the slots of every other series are staggered with respect to the slots of alternate series, all of the hairs encountered by the cutting head during each sweep of the head in connection with a shaving or hair depilation operation are encountered by the slots and are subjected to the shearing action of the cutter against the cutting edges at the inner face of the cutting head.

In Figs. '7 to 14, inclusive, I have shown other methods of forming the slots according to my invention. In Figs. 7 and 11, male and female dies 52 and 53 are shaped for punching slots 54 in the thin strip 55 which forms the cutting head or shearing blade. In Figs. 8 and 12 a second set of male and female dies 56 and 51, respectively, form the indentations 58 and projections 59 on the transversely perforated strip 55. In Figs. 9 and 13 a set of male and female dies 60 and 6I, respectively, form the indentations and projections and also slit or perforate the metal strip 62 in a single punching or stamping operation. In Figs. and 14 a second set of male and female dies 63 and 64, respectively, further perforate the indented and slitted parts of the strip 62 to give greater width to the slots. All of the foregoing operations are formed with the strip flat.

My invention contemplates finishing the inner face of the cutting head in such manner as to insure the provision of cutting edges either flush with such inner face or spaced slightly inwardly from such face, thereby insuring most eflicient shearing action by conjoint use of the cutter. This ls accomplished preferably by exing the perforated portion of the cutting head or strip to a curvature approximately the same as it occupies when in operative position and lapping the inner face by means of a lapping tool of approximately the same diameter. This step in the operation of manufacture is illustrated in Fig. 15 in which one of the cutting head strips here designated 65 is held on an annular lapping bar or arbor 66 in substantially the same shape and condition as when it is in operating position in a shaver. Suitable means may be employed for this purpose, and I have here shown a spacer 61 connecting the flat sides of the strip, holding them in parallel relation. By suitable motion of the lapping bar the projections left on the face of the strip as a consequence of the punching or forming operation will be removed or reduced by abrasion, leaving a smooth, mirror-like inner face. Preferably a force is applied downwardly on the spacer 61 either by spring means or a weight or suitable pressure-applying means, so that the perforated portion of the strip will be held down against the rotating arbor. with substantially the same pressure as applied by the spring elements 33 when holding the strip in operative position in a shaver. Thus I am able to obtain a very fine degree of precision in the sharpness of the shearing edges at the face' of the strip and to locate these edges precisely in the arcuate plane along which the shearing edge of the cutter travels. In other words, the cutting edges at the inner end of the perforations will lie in a true arc coincident to the arc of travel of the oscillating cutter, thus giving a very eiiicient cutting action. By making the perforations in the form of slots and arranging these at an angle to the plane of travel of the cutter, a fine shearing action is obtained. By making the lapping arbor slightly smaller in diameter so that thecurvature of the perforated portion of the strip is vslightly less than that which it occupies in operative position, the opposed cutting edges at the face of the strip will be projected slightly inwardly from the inner face of the strip when the latter is expanded or opened to its operative position, thus further insuring sharp cutting action. Another phase of my invention in this respect is to expand or open the strip 65 to a Wider diameter as shown in Fig. 17, in which case the semi-circular shoulders 68 and the side walls 69 of the bracket or the equivalent on which the strip is supported in the shaver, are shaped to provide for this larger diameter. Under this condition the opposed shearing edges 'l0 will be projected slightly inwardly in the manner illustrated in Fig. 18. This is due to stressing the metal by reason of deflection from the shape in which these edges were finished, the deected areas being diagrammatically illustrated by the dotted lines in Fig. 10. Contrasted to this, Fig. 16 shows the opposed cutting edges 1| of the finished strip 65 in the normal condition in which they are finished, that is, flush with the inner face. When the strip is removed from the lapping xture or from its operative position in the shaver, it will assume a flat condition, as illustrated in Fig. 3. This makes for convenience in handling and packing as well as in replacement of cutting heads. The lapping arbor may be of copper or it may be of any suitable abrasive material, the step of removing or reducing the projecting material being accomplished without disturbing the temper of the spring steel strip. Instead of entirely removing the projecting material, this operation may becarried on only suiiiciently to reduce the projection, thus leaving a series of smooth finished surfaces in an arcuate plane slightly spaced from the face proper of the strip.

' single stroke of the moving die element.

This form of my invention may be used particularly where the perforations are quite close together, and in such staggered relation as to insure continuous bearing contact for the cutter, thus reducing friction between the oscillating cutter and the cutting head.

In practice I have made the width of the slots from .009" to .012", and a length of approximately 11g of an inch, using a strip of spring steel of .003". These dimensions are merely for purpose of illustration.

My invention also contemplates a cutting head having the characteristics disclosed in Figs. 19 to 22, inclusive. Here the strip of extremely thin metal designated by 12 is of somewhat different proportions from that shown in Fig. 3, it being employed in a commercial form of my invention. Instead of using elongated slots, I prefer annular perforations 13 closely positioned and arranged in rows longitudinally and transversely. The longitudinal rows indicated by AA are inclined with respect t the end edges 14, and the transverse rows indicated by BB are inclined also with respect to said edges. By reason of this staggered relation of the holes, the cutting edge of the cutter moving across the inner face of the strip is effective successively on the short lengths of hair projecting through these openings, as a result of which the cutting resistances as well as the wear on the cutting edge ls more evenly distributed. In this form there is also provided an imperforate area 'l5 for the purpose above described and elongated hair-discharge openings 'I6 anking each imperforate area. These annular perforations are preferably punched out in a single operation by male and female die members Il and 18, Fig. 23, and the inner face of the strip is lapped in the same manner as described above with reference to Fig. 15, thus removing any burrs or projecting metal and providing accurate shearing edges and a smooth surface on the inner face of the strip. Instead of depressing or displacing any of the metal of the strip in this punching operation, I here form merely annular through openings and in this way I am able to locate the openings closer together without weakening the metal structure. The openings at the outer face are then beveled or rounded at the corners as at 19 by separate means such, for example, as by an abrasive bufling tool 80 while the strip is held on a suitable stationary fixture 8|, as shown in Fig. 20. The tool 80 is shown being rotated in a clockwise direction and moved transversely -to the right across the shearing zone, thus reducing the corner edges to a greater degree at the side toward the left. Reversal of this operation smilarly reduces the corner edges at the side toward the left. This gives a somewhat elongated cavity or mouth at the entrance side of each opening as shown in Figs. 21 and 22, which facilitates entrance of the hair. I may, however, employ die elements such as 82 and 83 as shown in Fig. 24 for perforating the strip and indenting the outer corners by deflection of the metal in a 'Ihis form of die may also be used in making perforations in the form oi" slots.

My invention contemplates new and improved results in shavers of this type, particularly by reason of the provision of annular perforations arranged close together in a shearing area and providing maximum open area with maximum strength and maximum length of shearing edges. In actual practice with a cutting head of .003" thickness, I employ perforations of approximately .025" diameter-and space the holes approximately .040" from center to center with respect to each other. This gives an open area of approximately 35% of the shearing area of the head and gives annular cutting edges of considerable length. This 'construction also allows a comparatively large body of metal to insure strength throughout this area. In using a cutting head of .004. thickness, the perforations would be of slightly larger diameter, and when the cutting head is of .002" thickness, the openings should be of slightly less diameter. With my invention the hairs enter the perforations in all directions of movement o'f the cutting head, but their entrance is facilitated by the cavities 19 when the cutting head is worked back and forth in a transverse plane. By reason of the relatively large open area and the closeness with which the cutting edges are brought to the skin Without irritation, I am able to provide closer and more eiicient shaving than is possible with prior shavers of this general class.

'I'he methods of processes of manufacture are claimed in my copending application Serial No. 189,573, a division of this application.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention, in which- I claim:

1. In a shaver, a cutting head of extreme thinness to present a skin-engaging part provided with a plurality of hair-receiving apertures, a cutter, means for rapidly oscillating the cutter, and means for supporting the cutter in such manner as to exert during its movement pressure against that arcuate surface of the extremely thin cutting head which is directed away from the skin to produce a rapid shearing action in cooperation with the edges of the hair-receiving apertures, said apertures being confined to a given` zone, the cutter being so supported and operated that it traverses said 'zone and at each end of the oscillating stroke its cutting edge is disposed beyond said zone over an unperforated part of the cutting head, and hair discharging openings contiguous to the outer end of each said unperforated part. v

2. In a shaver, a cutting head of extreme thinness to present a skin-engaging part provided with a plurality of hair-receiving apertures, a cutter, means for imparting rapid movement to the cutter, means for supporting the cutter in such manner as to exert during its movement pressure against that arcuate surface of the extremely thin cutting head which is directed away from the skin to produce a rapid shearing action in cooperation with the edges of the hair-receiving apertures, that -portion of the cuttinghead containing the hair-receiving apertures being shorter in length than the path traveled by the cutter, whereby to prevent hair from being caught between the cutter and the cutting head upon re- `version of movement of the cutter, and hair discharging openings in thev cutter head beyond the cutter path at each end thereof.

3. A cutting head for a shaver comprising a strip of thin flexible metal having closely positioned hair-receiving openings, the strip being flexed so that its said perforated portion is in arcuate form, the convex side serving to rest against the skin when shaving and the concave side having cutting edges at the inner end of the perforations adapted to coact with a cutter in a shearing action for severing particles of hair projecting through the perforations, said cutting edges being spaced inwardly beyond the inner concave face of the cutting head.

4. A cutting head for a shaver comprising a strip of extremely thin spring metal having hairreceiving openings closely spaced over a medial area, an imperforate area contiguous to each longitudinal end of the perforated area and of such width as to provide a closed area at the end of each stroke of a cutter oscillated across the inner side of the perforated area, and hair discharging openings contiguous to the outer end of each imperforate area.

5. In a shaver, a cutting head having an arcuate portion of thin metal provided with closely positioned hair-receiving apertures confined to a given zone and further provided with an imperforate area contiguous to each end of said perforated zone, cutting means coacting with the inner arcuate side of the cutting head adapted to be rapidly oscillated in an arcuate motion for traversing said apertures in shearing engagement with the inner edges thereof, and means for so operating said cutting means and confining the oscillating stroke to a definite range of movement with relation to said perforated zone and said imperforate areas, in which movement that portion of the cutting means adapted for shearing engagement with the inner side of the head is disposed within the said imperforate area at each end of the oscillating stroke, and in which the said cutting portion of the cutting means is disposed outside of said perforated zone at each end of the oscillating stroke.

JOHN BRUECKER.

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