US2146643A - Dry shaving device - Google Patents

Description

T. J MURPHY Feb. 7, 1939.

DRY SHAVING DEVICE Filed Nov. 26, 1934 5 Sheets-Sheet l INVENTOR4 Mus-Y5 T. J. MURPHY Feb. 7, 1939.

DRY SHAVING DEVICE Filed Nov. 26, 1954 5 Sheets-Sheet 2 uumummuu mm m m w a 7 a 1.3 my 5 N 15 2 :1 M j BT MH M W HUM n J11. r

F 1? II EQE XIVENTOR ATTORNEYS- F eb. 7, 1939,

T. J MURPHY 46,643

DRY SHAVING DEVICE Filed Nov.- 26, 1954 5 Sheets-Sheet 4 ATTORNEY5 7, 1939. T. J. MURPHY DRY SHAVING DEVICE Feb.

Filed Nov. 26, 1934 5 Sheets-Sheet 5 INVEN OR W34 BY W ATTORNEYS.

Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE 13 Claims.

This invention relates to a shaving device, and more particularly to a so-called dry shaver in which the shaving operation is performed mechanically.without the 'use of soap and the like,

and has for an object to provide a device for this purpose which will give a cleaner and closer shave than devices now generally on the market and will be capable of cutting'hairs of greater length than similar shavers can do now.

Another object is to provide a shaver of this type which will shave equally efl'ectively in each of the movements in opposite directions'so that the device may be operated by moving it back and forth over the surface to be shaved, two opposed shaving features being provided and so arranged that one operates on moving in one direction and the other on movement in the opposite direction and each acting as a gauge or guide for the other to retain it at the proper angle for best cutting and most eifective operation.

A further object is to provide with this type of shaving apparatus an improved operating mechanism which gives rapid operation and plenty of power, and which operates without any make or break devices for the electric current and therefore will be more reliable in operation and may be operated indefinitely.

Other objects and advantages will become apparent as the description proceeds. It, however, 30 is to be understood that various modifications and changes may be employed without departing from the spirit of the invention and within the scope of the appended claims.

Referring to the accompanying drawings:

35 Fig. 1 is a side elevation of the device on an enlarged scale with one section of the enclosing casing removed and parts broken away to more clearly show the construction;

Fig. 2 is a transverse vertical section of the easing showing the internal mechanism in side elevation;

Fig. 34s a transverse section substantially on line 3-3 of Fig. 1;

Fig. 4 is a transverse section substantially on line 4-4 of Fig. 1;

Fig. 5 is a detailed section substantially on line 5-5 of Fig. 1;

Fig. 6 is a top plan view of the operating yoke for transmitting movement from the power de vice to the cutter;

Fig. 7 is a detailed section thereof substantially on line 1-1 of Figs. 2 and 6;

Fig. 8 is an edge elevation of the completed device;

Fig. 9 is a front view thereof;

Fig. 10 is a back view;

Fig. 11 is a side elevation of one of the laminations of the core piece;

Fig. 12 is a partial side elevation and a partial longitudinal central section of the cutter head; 5

Fig. 13 is a top plan view thereof;

Fig. 14 is an end view;

Fig. 15 is a transverse section of the cutter portion substantially on line i5l 5 of Fig. 13;

Fig. 16 is a side elevation of a cutter head of 10 slightly modified construction;

Fig. 16a is an end view thereof;

Fig. 1'7 is a view similar to Fig. 1 showing a modified construction;

Fig. 18 is a longitudinal section thereof sub- 15 stantially on line l8-l8 of Fig. 17 but showing certain of the elements in elevation;

Fig. 19 is a rear elevation of the device of Figs.

17 and i8;

Fig. 20 is a transverse section substantially on 20 line 20-20 of Fig. 17;

Fig. 21 is a detailed section on line v2l-2l of Fig. 1'7

Fig. 22 is a detailed section substantially on line 22-22 of Fig. 17; 25

Fig. 23 is a plan view of one of the laminations of the core for the operating device in Fig. 17;

Fig. 24 is a vertical section through a plug-in device for operating the shaver, the section being substantially on line 24-24 of Fig. 25;

Fig. 25 is a longitudinal section substantially on line 25-25 of Fig. 29; v Fig. 26 is a side elevation; Fig. 27 is a side elevation at right angles to Fig. 26;

Fig. 28 is a transverse section through the easing substantially on line 28-28{-, of Fig. 24 and showing the enclosed elements intop plan view;

Figs. 29 and 30 are transverse sections substantially on lines 28-29 and 30-30 respectively of Fig. 24;

Fig. 31 is a wiring diagram for the electrical apparatus;

Fig. 32 is a wiring diagram for an alternative wiring;

Fig. 33 is a wiring diagram for another modification; and

Fig. 34 is a similar wiring diagram for another modification.

Referring first to Figs. 1 to 16a, the device comprises an enclosing casing indicated generally at l and comprising two separable sections 2 and 3 held together by any suitable means such as transverse screws or bolts 4 extending through one section, as section 3, and threaded into metal inserts, such as indicated at 5 molded into the other section 2 at the upper end and a short transverse bolt or screw 6 at the opposite end. This casing may be of any suitable material, but is preferably of molded electrical insulating material that is a phenolic condensation or similar product, such as Bakelite.

Mounted in and enclosed by this casing is the mechanism for operating the shaver which is included in the shaving head indicated as a whole at I and mounted in an offset portion 8 formed in the upper end portion of the section 2 of the housing or casing. The shaving head 1 is of rectangular cross-section and is mounted in a similarly shaped opening 9 in the offset 8. It is preferably inclined to the body at an angle of about 45", as this seems to be the most convenient angle for the body to be easily held in the hand during the shaving operation, but I am not limited to this angle as the head may be located in any position found most desirable, and even may not be inclined at all but may extend from the end of the casing and be substantially parallel with the axis thereof, if desired, as shown in the modification of Figs. 17 and 18. The shaving head I may be held in the casing by any suitable means, but a convenient way of mounting it is by a pair of set screws l0 threaded into metal inserts ll molded in the casing, these screws clamping against the side of the head and holding it in position. Preferably, the side of the head has slight recesses I2 to receive the ends of the set screws to more effectively clamp the head in position.

This shaving head is a material advance in the art and is shown more in detail in Figs. 12 to 160. In the form of Figs. 12 to 16 it comprises a metal block or body l3 having a longitudinal slot H in one edge leading to a longitudinal passage II, which edge is curved as shown at l5. On the opposite edges of this slot are a series of narrow guide or guard teeth 6, which are spaced apart by narrow slots for entrance .of the hairs in shaving. Inwardly of these guard teeth is the longitudinal guide passage H, which in this form is substantially circular, in which is mounted a slidable steel cutter [8. This cutter is mounted to reciprocate back and forth longitudinally of the head in the passage I1 and has an eccentric longitudinal passage l9 adjacent its upper edge, with a slot 20 leading from this passage in alignment with the slot I4 in the block i3. Leading transversely from the edges of the slot 20 in the cutter are narrow slots forming the narrow cutting teeth 2| which as the cutter l8 reciprocates slide back and forth over the undersides of the guard teeth 16 and the slots between them, the edges of these teeth on the cutter and the block giving a shearing action to cut hairs which may enter the slots between the teeth. It will be seen from Fig. 15 that the teeth on the cutter i8 increase in thickness back from the points or free ends of the teeth so that the teeth have additional strength and support. Also, the guard or guide teeth on the head l3 taper backwardly from their ends or edges in the same manner giving them good strength and stiffness. The outer surface may be ground off substantially flat, as indicated at 22, providing a substantially flat surface to engage the skin and also permitting the free edges or ends of the teeth on the opposite sides of the slot It being ground to a very thin edge so as to give a out very close to the surface of the skin and thus a very close shave.

It will be evident that from this: construction there are two opposed cutting devices extending or facing in opposite directions and spaced from each other the width of the slot 14. Each of these cutting devices includes a set of guard or guide teeth on the head or body l3 and a set of reciprocating or cutting teeth cooperating therewith, both of which sets of cutter teeth are on the reciprocating cutter 18. Therefore, as these cutting devices are held against the surface of the skin and the head is moved over the surface back and forth in a. direction transversely of the slot l4, first one cutting device on one side of the slot operates as a shaving device, and then when it is moved in the other direction the other cutting device on the opposite side of the slot operates as a shaving device, and therefore as the shaver is moved back and forth over the surface there is always a shaving device with the free ends of its guard teeth moving forwardly, which is the proper movement and relation for shaving. It will also be seen that as one of the shaving devices is operating forwardly in the cutting direction the other is moving ahead of it and against the surface of the skin, and therefore formsa guide to always maintain the device which is doing the cutting at the proper angle with relation to the surface of the skin for the best cutting effect and prevents digging into the skin, and to secure this proper angle, all the user has to do is to hold the end of the cutting head .squarely against the surface of the skin, The passage l9 collects and conducts the cut off hairs from the shaving devices so they are kept clear at all times.

To secure a cutting effect it is of course necessary that the cutter i8 be reciprocated in a direction longitudinally of the slot M, or, that is, transversely of the guard teeth 16, and immediately back of the guard teeth and be held against the back of these teeth for the proper shearing effect. The amount of movement of the cutter should be at least equal to the distance between the teeth 16, but it maybe several times this amount, if desired.

This reciprocating motion of the cutter l8 may be secured in various ways, but in'the present instance I have provided an electrically operated reciprocating drive element 23 connected with the cutter 18 by means of a drive pin 24. This drive pin 24 is fastened to the cutter H! by any suitable means such as screw threads 25 and projects from the body 13 at the opposite edge from the cutter l8 where it has a tapered end 26 entering a socket or opening 21 in the operating element 23. In order to prevent electrical injury to the user of the device should any of the electrical contacts become grounded, this opening 21 is preferably in an electrical insulating bushing 28 carried in the member 23. In order to hold the cutter H3 in proper alignment the driving pin 24 passes through an opening in a guide plunger 29 mounted for reciprocating movements in a longitudinal passage 30 in body 13, as this can be given a good accurate sliding fit. It will be evident that as this guide plunger is spaced some distance from the cutter considerable wearbetween this guide plunger and the body would permit very little turning movement of the cutter out of alignment, and as this plunger can be given an extensive bearing surface in the body l3 it can be used indefinitely without sufficient wear being caused to have aux objectionable efiect on the alignment of the cutter. To lighten the guide plunger 29 then the ends sealed with discs 32. To permit proper movement in the body the pin 24 passes through an elongated slot 33.

In the form of Figs. 12 to 15 the body or block i3 is made in one piece, but if preferred, it may be made in two pieces 34 and 35 as shown in Figs. 16 and 16a, the line of separation being preferably substantially on the center line of the block and the sections secured together by any suitable meanssuch as the rivets 36. This construction makes the device somewhat easier to manufacture as the two opposite sides of the passages i1 and 30 can be milled in the two sides of the block, and then when these two sides are placed together in alignment these guide passages are completed. With this arrangement the cutter i8 and the plunger 29 need not be circular in cross section but may be square, rectangular or other shape.

The operating device for the cutter as shown in Figs. 1 to 6 comprises a laminated core of good magnetic material, such as soft iron, having three connected poles 31, 38 and 39 spaced from each other the proper distance and embraced by the coils 49, 4! and 42 respectively. Extending over the top of the center pole is an armature 43 of magnetic material and it is preferably U-shaped so that the opposite end portions 44 extend between poles 31 and 39 and 38 and 39, but with sufficient clearance to permit the armature to have the proper reciprocating movement. The armature should not come in contact with the pole pieces and therefore resilient live rubber buffers in the form of blocks or discs 45 are provided between these arms and one of the pole pieces, in the present instance between these arms and the center pole 39 so that the arms are nearer the outer poles 37 and 38. This armature is carried by a yoke 46 extending over the top thereof and to which the armature is secured by any suitable means, such as the rivets 41. The opposite ends of this yoke extend outwardly and downwardly as'indicated at 48 in opposite directions over the outer poles 31 and 38 and are connected at their free ends as by rivets 49 with supporting flexible spring elements 50. These flexible spring elements are supported at their lower ends by any suitable means, such as screws 5! on a supporting strap 52 fastened to the lower ends of the laminated core by means of the rivets 53, which also secure these laminations together. This strap 52 should be of non-magnetic material as should also the yoke 46. To prevent the yoke turning on the spring supports 50 the free ends thereof are provided with short flanges 54 engaging the opposite edges of the support 50. These spring supports permit the armature to reciprocate in substantially a straight line and they have sufficient resiliency to normally bring the armature back to the central or neutral position when not acted upon by the magnetic elements. On the opposite side of the core from the strap 52 may be a supporting strap 55 also secured to the laminated core by the rivets 53, and this strap is provided with a downwardly extending ear in which may be threaded a supporting screw 56 extending through the rear wall of the casing. This effectively mounts the cores and coils at the lower part of the casing. The yoke may be stiffened at the bends by striking out ribs 48a, and the supporting members 58 may also be strengthened by longitudinal ribs 50a struck therefrom.

The cutter operating element 23 is mounted on the yoke 46 so as to reciprocate with it. For this purpose the yoke is provided with a rearwardly extending arm 5? to which one end of the member 23 is connected by any suitable means, such as the rivets 58. This arrangement gives sufficient length to the arm or member 23 so that it can have yielding resilient action tending to always press the socket 21 tightly against the tapered end 26 of the operating pin 24. This automatically compensates for any wear between the pin and the socket, and it always holds the teeth on the cutter l8 closely against the underside of the guard teeth l6 and automatically compensates for wear between the cutter and the guiding head to give proper cutting action of the cutter.

The upper part of this operating mechanism is securely anchored to the casing by a screw 59 extending through the center pole 39 and threaded into a metal insert 60 molded in a lug or boss 6| projecting inwardly from the back wall of the casing section 3 so that the upper end of the core and associated mechanism are rigidly anchored to the casing. The core may also be braced by legs 31 and 38 resting against lugs 61a on the rear section 3 of the casing. A plate 62 is preferably placed against the front of the center core 39 through which this screw 59 passes, and at its lower end is provided with an outwardly extending flange 63 resting on the tops of the coils 40, 4| and 42 to hold them in proper position. The laminations of the core at the poles 3'! and 38 may be secured together by rivets 64,

The flattened or oval shape of the body makes it easily gripped and held in the hand of the operator. The cord 65 for the electrical leads to the various operating coils preferably extends into the casing at the lower end thereof and laterally from one edge as shown. The opening into the casing is preferably provided with ribs 66 to grip the covering on the cord when the casing sections are clamped together to securely hold the cord in position and prevent strain on the cord from pulling the lead wires away or breaking their connections to the coils. The casing may be provided with an opening 51 on the opposite side in alignment with the opening for the cord 65 to receive the ends of a cord loop 68 whereby the device may be hung on a hook or any suitable support when not in use. A metal grip or sleeve 69 may be clamped about the ends of this cord loop in the casing to prevent its withdrawal through the opening Bl.

I now refer to the modification shown in Figs. 17 to 23. It will be noted from the above description that in the form of Figs. 1 to 6 the reclproeating cutter i8 is connected directly to the armature 43 so as to move with it. In .the form shown in Figs. 17 to 22, however, the operating armature is arranged on the longer arm of a lever with the connection to the cutter on the shorter arm so as to transmit greater operative force to the cutter. To secure this eifect the laminated core indicated as a whole at 10 is reversed so that the three pole pieces H, 12 and 13 are at the lower ends of the casing 14, which casing is also composed of two sections 15 a d 16 separable at the longitudinal line of the casing. This casing is also preferably made of a phenolic condensation product as Bakelite so that it is electrically insulating and is moisture proof. With the arrangement of the pole pieces as shown it will be noted that they are at the opposite end of the casing from 'the cutter head I. Extending over and operated by the magnetic effect of these pole pieces is an armature 11 carried by lever arms 18, one on each side of the core and inturned at their lower ends as shown at 19 on which the armature is mounted by any suitable means such as screws 80. The lever arms I8 are pivotally mounted at 8| on a transverse support 82 extending through a passage 83 in the center pole of core and carried by downwardly extending ears 84 in supporting plates 85 mounted on the opposite sides of the laminated core at the upper ends thereof. These plates and the core are bound together and mounted in the casing by transverse bolts 86 which extend through openings in the casing sections I5 and "I6 and in bosses or lugs 81 on the inner walls of these sections. These bosses have recesses 88 at their inner end to receive the clamping nuts 89. Thus the laminations and the supporting plates 85 may be clamped together by the clamps 89 and then, after assembling, the unit mounted by placing the casing sections in position with the free ends of the bolts extending through the openings in the lugs 87, and can be clamped to the casing by the nuts 98.

The lever arms I8 are preferably in one piece or in substantially inverted U-shape, and they are connected at their upper ends by a transverse piece 9 I. This lever is connected to the projecting end 26 of the driving pin for the cutter I8 by the spring arm 92 connected to the upper portion of one of the lever arms I8 above the pivots 8| as indicated at 93. This spring arm acts the same as the spring arm 23 in the first form to reciprocate the cutter and to tend to force it toward and hold it closely against the underside of the guard teeth I 6 of the cutter head. The pivots 8| may be of any suitable type but preferably of headed pins as shown passing through the arms I8 and into a longitudinal passage 94 in the element 82. It will be evident that as the pivot 8| is considerably nearer to the connection to the cutter than it is to the armature II this armature has considerable leverage advantage to apply greater driving force to the cutter.

The armature and the levers 18 are normally held in the neutral or central position by two coil springs 95 connected to the center of the armature by a pin 96. At their opposite ends the springs are connected to studs 91 on a supporting plate 98 clamped against the sides of the pole pieces and to the casing by bolts 99 passing transversely through this plate and another plate IIIII on the opposite sides of the pole pieces, and to which pole pieces the plates are secured by nuts I8| on the bolts 99. When assembled in the casing the free ends of these bolts 99 extend into openings I02 through bosses I03 on the inner walls of the casing sections, which bosses have recesses I84 for the nuts IIJI, and then the whole is clamped to the casing sections by nuts I05 in recesses in the outer walls of the casing, and it will be seen that with these bolts 99 and the bolts 86 the whole mechanism is securely and firmly mounted in the casing. The laminations of the core and the plates 98 and I may all be clamped together by transverse rivets IIlIS passing through the plates and the pole sections II and I2 of the laminations. One of the laminations is shown in Fig. 23 and as will be seen the central pole section 13 is divided for the greater portion of its length by a slot 13a making a central pole really a double pole.

- The lead cord 65 leading to the operating coils I91 and I08 is mounted in the lower end of the casing the same as shown in Fig. 1 as is also the loop 68 for hanging the device on a hook or other suitable support.

Various wiring arrangements of the electrical operating devices which can be used are illustrated in the wiring diagrams of Figs. 31 to 34. In the wiring diagram of Fig. 31 there is a coil on each of the pole pieces or legs of the core, coil 40 being on the pole or leg 31, coil 4I on the pole or leg 38, and the central coil 42 on the central pole or leg 39. This central coil 42 is in reality a double coil or in two sections because the lead I09 from the upper end ofthe coil 4| is connected to the center thereof as indicated at I ID. The lower end of the coil 40 is connected to the lower end of the coil 4| by a wire III, and the upper end of coil 40 is connected by the lead II2 to one side II3 of an alternating current supply. The other side of this alternating current supply is connected between two rectifier elements I I and I I8, which may be a single rectifier unit preferably of the cupric oxide type and the lead I I4 connected to the center plate of this unit. The outlet from the rectifier H8 is connected by a lead II8 to the upper end of the coil 42 while the lower end of coil 42 is connected by a lead III to the inlet side of the rectifier II5. It will be seen from this arrangement that the central pole 39 is always of the same polarity while the other poles 31' and 38 are alternatively of a different polarity, and when the flux of the pole 31 is zero that in 38 is at a. maximum and vice versa. The three coils 4|], 4| and 42 in the arrangement illustrated are all wound in the same direction, and in view of the various connections certain of them have different effects at different times. Thus for example for one-half of a cycle of the A. 0., supply current is entering through the lead H4 and it cannot pass through the rectifier II5 but can pass through the rectifier IIS and by lead M8 to the upper end of coil 42 and out through lead I09 to the upper end of coil 4|, then from the lower end of this coil through the lead III to the lower end of the coil 48 and out the upper end thereof back to the other side II3 of the line or A. C. supply. Thus if we assume that during this half cycle the center pole 39 is north because of the excitation by the upper half of coil 42 then the two poles 31 and 38 would be of south polarity, and the excitation by coil 4| would be of north polarity and that would cancel or suppress the south polarity of pole 38, while the excitation of coil 49 would be of south polarity and would therefore add to or build up the south polarity of pole 31, and the armature 43 will be shifted in one direction toward the pole 31. Now in the other half of the cycle current will flow in through the. lead II2 to the upper end of the coil 40, from the lower end of this coil through the lead III to the lower end of the coil 4| by lead I09 from the upper end of this coil to the center of coil 42 and through the lower half of this coil to the lead III and through rectifier II5 to the other half N4 of the line or A. C. supply. As before, the central leg 39 is still of north polarity while the polarities of coils 40 and 4| are now reversed so that 31 is now of minirr um polarity (coil 40 being now north) and the south polarity of 38 has now been built up or added to by the south polarity of coil 4| so that it is now of maximum polarity. This is because the excitation of coil 48 is now of north polarity and suppresses or cancels out the south polarity of pole 31 while the excitation of coil 4| is now south and therefore adds to or builds up the south polarity of pole 38, and the armature is shifted in the opposite direction. Thus it will be seen be of north polarity as the coils may be wound to excite the center pole of south polarity so long as it is excited in the same sense during both halves of the cycle. with this arrangement of windings and connections the function of the windings 40 and H is to suppress alternately the excitation'of the outer poles 31 and 38 of the system and while one is being suppressed to build up or add to the flux on the other pole. Therefore the armature and the cutter are given one complete back and forth movement or two cutting strokes for each cycle of the electric supply current and no make or break devices are required. There are also no rotating elements the rotating motion of which must be converted into a reciprocating movement. The two halves of coil 42 are therefore D. C. exciting coils' while coils 40 and" are A. C. coils. Only sufllcient spring action is required to hold the armature in the center or interm diate position.

Referring to Fig. 32, thisfigure shows a different arrangement of coils and connections for securing the same result. In this arrangement there are no coils on the center pole 39 butthere are two sets of D. C. exciting coils on the outer legs 31 and 38, the first set being indicated at H9 and I20 and the second at I2I and I22,

. while the two A. C. coils in series are indicated at I 23 and I24. As shown the lower end of coil I23 is connected by lead I25 to one side I28 of the A. C. supply while the other end of this coil is connected by the lead I21 to the upper end of the coil I24. These coils are'so wound as to excite their respective cores with the same polarity. The lower end of coil I24 is connected by leads I28 and I29 to the lower end of coil I20, theupper end of this coil being connected by lead I30 to the upper end of coil II9 while the lower end of this coil is connected by lead I3I to the outlet side of'the rectifier 32. The lead I28 is also connected to the lower end of coil I22 the upper end of which is connected by lead I33 to the upper end of coil I2I the lower end of which is connected by lead I34 to the inlet side of the rectiiier I35. nating supply, indicated at I38, is connected between the two rectifiers I32 and I35. The two coils H9 and I20 polarize the outer legs 31 and 38 in a different sense, that is one south and one north polarity during one half of the cycle. The two coils I2I and I22 have the same effect as the coils H9 and I20 on the next half of the cycle. Therefore, if we assume that during onehalf cycle the current enters through lead I38 it will pass through rectifier I32 to coil II9 polarizing the leg 31 of south polarity. It will also pass through 0011 I20 polarizing leg 38 with north polarity. It will then pass by lead I28 through the coil I24 which will tend to polarize theleg 38 with north polarity which adds to the north polarity of the coil I20. The current then passes through the coil I 23 to the other lead I28 of the A. C. supply. This polarizes the leg 31 with north polarity which cancels or suppresses the south Thus it will be seen that The other side of the alterpolarity of the coil II9. Now on the other half of the cycle as current enters from the leg I28 11; passes throughthe coil I23 exciting pole 31 with south polarity and passes through the coil I24 to excite pole 38 with south polarity. It then passes through the coils I22 and I2I which excite legs 38 and 31 respectively with north and south polarity and out through the rectifier I35 to side I36 0! 'the'supply. In this case the coil I23 has built up or added to the south excitation of coil I2I'whlle coil I24 has cancelled out or suppressed the north excitation of coil I22, which is just the opposite of the effect on the first half of the cycle.

Another arrangement for securing this effect is shown in Fig. 33 in which there is a coil on each of the three legs of the core. Coil I 31 is connected to one side I38 of the A. C. supply while at its upper end it is connected by lead I 39 to the upper end of the coil I40 on leg 38 which is connected at its lower end at I between the rectifiers I42 and I43. The other side I44 of the A. C. supply is connected between the rectifiers I45 and I48. The lower end of the center coil I41 is connected at I48 between the rectifiers I43 and I48 while the upper end of this center coil is connected by lead I49 between the rectifiers I42 and I45. If now we assume that during one half of the cycle current enters through lead I44 to pass through rectifier I45 to the center coil .I41, exciting pole 38 with north polarity (and legs 31 and 38 consequently of south polarity), it then passes by connection I48 through rectifier I43 to the lower end of coil*I40 tending to excite leg 38 with south polarity. It then passes by lead I39 to enter top of coil I31 tending to excite leg 31 with north polarity and passes to the other side I38 of the line. It will thus be seen that it has built up or added to the south polarity in the leg 38 due to the excitation of coil I41 and it has suppressed or cancelled out the south polarity in the leg 31. On the other half of the cycle current enters from the lead I38 to the lower end of coil I 31 exciting leg 31 with south polarity, passes by lead I39 to the upper end of coil I40 exciting leg 38 with north polarity and passing through rectifier I42 to the upper end of center coil I41 exciting the center pole 39 with north polarity the same as on :excitation of leg 38 is suppressed or cancelled out .and that of leg 31 added to or built up during one-half of the cycle, and the excitation of 31 is suppressed or cancelled out and that of 38 built up on the other half of the cycle.

Still another arrangement is shown in Fig. 34. In this arrangement there is no coil on the center leg 39. There are two D. C. exciting coils I50 and I5I one on each leg 31 and 38, the upper end of I50 being connected by lead I52 to the upper end of coil I5I. The lower end of I50 is connected by lead I53 connected between the rectifiers I54 and I55 while the lower end of coil I5I is connected by lead I58 between the rectifiers I51 and I58. Also, on the legs 31 and 38 are the two A. C. coils I53 and I80 connected at their upper ends by the leads I 8|. The lower end of coil I59 is connected by lead I82 to one side I83 of the A. C. supply. The lower end of coil I 60 is connected by lead I 84 between the rectlfiers I54 and I51 The other side I85 of the A. C. supply is connected between the rectiflers I55 and I58.

If we assume now that current enters during one-half cycle from side I65 of the A. C. supply it passes through the rectifier I55 to the coil I50 and then through the coil I5I, one of which, for example coil I50, is wound to excite pole 31 with south polarity, and the other coil I5I to excite leg 38 with north polarity. This current then passes through the rectifier I51 and lead I64 to the coil I60 which excites leg 38 with north polarity. This adds to or builds up the north polarity of coil I5I. The current then passes by lead I6I to coil I59 and by lead I62 to the other side I63 of the A. C. supply. This excites coil I59 with north polarity which cancels out or suppresses the south polarity of the coil I50. On the next half of the cycle the current enters from I63 through lead I62 to coil I59 exciting leg 31 with south polarity, then by lead I6 I to coil I60 exciting leg 38 with south polarity. Then goes by lead I64 to rectifier I54 and by lead I53 to coil I50 which as before excites leg 31 with southpolarity, and then goes by lead I52 to coil I5I which also as before excites leg 38 with north polarity. It then passes by lead I56 through rectifier I58 to the other side I65 of the A. C. supply. During this half of the cycle the south polarity of coil I59 builds up or adds to the south polarity of coil I50 while the south polarity of coil I60 cancels out or suppresses the north polarity of coil I5I which is just the opposite of the effect of the first half.

In each one of the examples given it is of course not necessary that the coils be wound in the directions shown so longas the D. C. coils are wound and connected so as to excite the core in the same direction or with the same polarity during both halves of the cycle while the A. C. coils are so wound and connected as to suppress the flux in one of the outer legs and build up that in the other leg during one-half of the cycle and then suppress the flux in the second outer leg and build up the first outer leg during the second half of the cycle, or merely to alternately suppress the flux in the two outer legs during the two halves of the cycle.

It is preferred in each arrangement to surround the center pole or leg with a copper tube 39!! to sustain the fiux and reduce stresses on the rectifiers. It prevents the field from collapsing between impulses and so protects the exciter windings from voltage stresses.

The rectifiers, that is the two rectifiers H5 and H6 of Fig. 31 and the rectifiers I32 and I34 of Fig. 32 may be mounted in the plug-in device for connecting the shaver to an outlet receptacle or a lighting socket of a house wiring system, as shown in Figs. 24 to 30. The same device can be used for mounting the four rectifiers of Figs. 33 and 34, it being only necessary to add the two additional rectifiers in the proper relation as indicated in the diagrams of Figs. 33 and 34. In each instance there are two contact blades I66 and I61 projecting from one end of the plug-in device which when inserted in an outlet receptacle in the usual manner connect the device with the house wiring system, or, that is, the A. C. current supply. Also, in each instance there are three leads extending from this plug-in device to the coils in the shaving device. We will assume for illustration that blade I66 represents the side I I3 of the A. C. supply. In the arrangement of Fig. 31 it is connected in the plug-in device to lead II2 which leads to the coil 40. This blade includes an enlarged central portion I68 provided with a lug I69 to which the lead II 2 is soldered.

A plate I10 is insulated from the blade I 68 by insulation HI and to this plate I10 is connected the lead II 1 leading to the lower end'of coil 42. The other blade I61 is offset so as to be connected to a central plate I12 and on the opposite side of this plate I12 from the plate I10 is a third plate I13 connected to the lead I I8 from the top end of coil 42. Between plates I13 and I12 is the rectifier 6, while between the plate I12 and the plate I10 is the rectifier II5, these rectifiers being preferably of the usual dry plate rectifier of the cupric oxide type which as is well known permits current to pass in one direction but prevents it from passing in the opposite direction. Thus I have shown the rectifiers as each composed of two copper plates I14 each treated on one side with the oxide, separated by a lead wash-er I15 against the oxide side to give better electrical contact. All of the plates with the blades I66 and I61 may be assembled and clamped together as a unit by a central bolt I16, the plates being insulated from each other and this bolt by an insulating sleeve I11. The blade I66 may also be insulated by an insulating washer I18 between it and the nut or head I 19 of the bolt, with a similar insulating washer I at the opposite side. The Whole device may then be mounted in a casing of molded insulating material, preferably a' phenolic condensation product, such as "Bakelite; The casing shown is in two sections I BI and I32 provided with recesses I83 to receive the head and nut of the bolt to hold the assembled rectifier unit in proper location in the casing and for compactness, the sections being secured together by transverse bolts I84 and I85. Bolt I85 also preferably passes through lugs or bosses I86 extending from the inner walls of the two side sections so that the bolt is thoroughly insulated. At the upper end the casing has an opening for the cord I81 carrying the three leads II2, II 1 and H8, and this opening has ribs I 88 to grip the rubber covering of the cord so as to take any pulling strain on the cord off the connections of the leads to the rectifier plates, and thus prevent these connections being broken by a pull on the cord.

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

1. In a device of the character described, a cutter head comprising a body having a longitudinal passage adjacent one edge with a longitudinal slot in said edge communicating with said passage, the opposite edges of said slot comprising closely spaced guard teeth extending transversely of the slot, a cutter in said passage having two rows of cutter teeth at the inner sides of the guard teeth to cooperate therewith, and means for reciprocating the cutter in a direction longitudinally of the slot.

2. In a device of the character described, two spaced cutting devices each comprising a set of spaced guard teeth and a set of cutter teeth cooperating therewith, said cutting devices being arranged in opposition to each other and facing in opposite directions, and means for reciprocating the cutter teeth in a direction transversely of the guard teeth.

3. In a device of the character described, a cutter head comprising a body having at one and two spaced rows of guard teeth facing in opposite directions with the free ends of said teeth toward each other, a separate set of cutter teeth cooperatirfg with each row of guard teeth, said two sets of cutter teeth being spaced from each other with the free ends of the teeth in each set toward the other satiand means for reciproeating the cutter teeth in a direction transversely of the guard teeth.

4. In a device of the character described, two spaced cutting devices each comprising a set of guard teeth and a set of cutter teeth, said devices being arranged so that the free ends of the teeth face in opposite directions and toward each other so that as the device is moved back and forth with the guard teeth against a surface each set alternately acts as a guide for the other set to hold it at the proper angle for cutting, and means for reciprocating the cutter teeth in a direction transversely of the guard teeth.

5. In a device of the character described, a cutter head comprising a body having a longitudinal passage adjacent one edge and a longitudina'l slot in one edge leading to the passage, transverse guard teeth on each edge of the slot, a. reciprocable cutter in the passage having an eccentric longitudinal passage therein and a slot leading therefrom in alignment with the first slot, the edges of said slot in the cutter being provided with transverse cutter teeth cooperating with the guard teeth, and means for longitudinally reciprocating the cutter.

6. In a device of the character described, a cutter head comprising a body having a curved edge having a longitudinal slot, opposed cutting devices at the opposite sides of this slot and facing each other, each device including a row of guide teeth at the edge of the slot, a reciprocable cutter having two spaced rows of cutter teeth one row on each side of the slot cooperating with the guard teeth, and means for reciprocating the cutter in a direction longitudinally of the slot.

7. In a device of the character described, a cutter head including a body having a curved edge and a cylindrical passage adjacent said edge, said edge having a longitudinal slot communicating with said passage provided with a series of guide teeth in the opposite edges thereof, a cylindrical cutter in said passage having an eccentric passage and a slot leading therefrom in alignment with the first slot and provided with cutting teeth on the edges of the second slot cooperating with the guard teeth, a guide passage in the head parallel with the first passage and spaced therefrom on the opposite side of the cutter from the slot, a guide plunger reciprocable in the latter passage, and an operating pin for the cutter connected with the cutter and the guide plunger so that the plunger keeps the cutter in alignment with the guard teeth.

8. In a device of the character described, a cutter head including a body having a longitudinal cylindrical passage adi n one edge, and a second longitudinal passage spaced from the first passage, a cylindrical cutter reciprocable in the first passage, said cutter and body having aligned slots having opposite edges and provided on these opposite edges with cooperating cutting and guard teeth respectively, a guide plunger reciprocable in the second passage, and a connection froin the cutter to the plunger so that the plunger prevents the cutter from turning in its passage.

9. In a hair clipper, a skin contacting member, adapted to be passed over the skin for clipping hair therefrom, said member provided with sets of opposed teeth extending toward but not reaching each other and separated by slots and a cutter provided with sets of similarly opposed teeth and operating adjacent the member and cooperating therewith to clip hair from the skin as the clipper is passed thereover.

10. In a device of the character described, a circumferentially slotted housing, a circumferentially slotted cutter member cooperating therewith, said housing and member having longitudinal channels disposed thereon transversely of and intersecting the said slots.

11. A device of the character described comprising a housing having a transversely curved portion provided with opposed teeth extending toward but not reaching each other, a cutter adjacent the housing and having similarly opposed teeth to cooperate with the housing teeth in cutting and means for operating the cutter.

12. In a hair clipper, a housing having a plurality of opposed by slots and provided with a channel arranged thereon transversely of the said slots to accommodate hair independently of its length to thereby present the hair to the slots as the hair clipper is passed over the skin, a cutter member ar-'- ranged adjacent the housing and means for oper-% ating the cutter 'member in relation to the hoiis ing.

13. In a hair clipper, a housing slotted to provide a plurality of opposed parallel spaced teeth separated by the slots, said housing provided with a channel arranged thereon transversely of said housing slots to accommodate the hair independently of its length to thereby present the hair to the slots as the hair clipper is passed over the skin, a cutter member arranged adjacent the housing and similarly slotted and channelled and means for operating the cutter member in relation to the housing.

THOMAS J. MURPHY.

.Patent No. 2,1l 6,6b,5.

' February 7, 1959.

THOMAS J. MURPHY. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: column, line 17, claim 5, for the word "one" read said;

Page 7, first and that the said Letters Patent should be read with this correction therein that the 88.1118 may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of September, A. D. 1959.

(Seal) Henry Van Arsdale, Acting Commissioner of Patents.

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