US2263955A - Electromagnetically operated mechanical shaver and like cutting appliances - Google Patents

Description

H. B. RANDOLPH 2,263,955 ELEGTROMAGNETICALLY OPERATED MECHANICAL SHAVER AND Nov, 25, 1941.

LIKE CUTTING APPLIANCES Flled April 20, 1938 2 Sheets-Sheet 1 Nov. 25,1941.vv

' H. B. RANDOLPH 2,263,955 ELECTROMAGNETIGALLY OPERATED MECHANICAL sHAvER AND LIKE CUTTING APPLIANCES 2 Sheets-Sheet 2 Filed April 20, 1938 Fig. 3.

Fig, 4.

3/7 @ffm Patented Nov. 25, 1941 ELECTROMAGNETICALLY OPERATED ME- CHANICAL SHAVER AND LIKE CUTTING APPLIANCES Harry Beckham Randolph, London, England Application April 20, 1938, Serial No. 203,143 In Great Britain May 7, 1937 16 Claims.

This invention relates to improvements in electromagnetically operated mechanical shavers and like cutting appliances.

It has been proposed to vibrate a safety razor blade by an electro-magnet of which the armature actuates a mechanical device which moves the blade supported in guides in a direction parallel to the cutting edges. In one construction one limb of an electro-magnet is provided with a head or pin which moves the blade or taps the handle when vibrated by alternating or interrupted current.

Hair clipping machines of the kind adapted for shaving the beard without use of water and soap are generally actuated by some form of motor mechanism embodying spindles, pivoted levers and bearing surfaces introducing liability to wear and noise as well as necessitating lubrication, attention and adjustment.

As is known a leaf spring xed at one end will vibrate at a high frequency when plucked at the free end. When the spring is loaded, for example, by a safety razor blade disposed in a plane at right angles to the direction of vibration a spring can be made to vibrate at a fairly high frequency and it is an object of the invention to utilise this phenomena in shavers and like cutting appliances.

It is a further object of the invention to provide an electric current actuated appliance comprising a cutting device carried upon a leaf spring ixed at one end and provided with an armature of `an electro-magnet and to so arrange this system that its natural period of vibration coincides with the frequency of the alternating electric current energising the magnet so that resonance is obtained.

A particular object of the invention is to provide cutting appliances comprising a pair of leaf springs fixed at one end and carrying a cutting device upon the free ends, this arrangement being adapted to be actuated by an electro-magnet energised by alternating electric current the frequencyl of which coincides with that ofthe natural period of vibration of the spring supported system.

One object of the invention is to provide an alternating electric current actuated appliance having a tuned leaf spring supported razor blade capable of actuation by said current to improve the cutting action.

Another object is to provide means for supporting a razor blade in a novel form of holdei permitting release of the blade to facilitate stropping thereof.

A further object is to provide an appliance of the dry shaver kind in which one of the clipping members is actuated by a leaf spring supported system, said system being tuned to resonate with the energizing alternating electric current.

A still further object of the invention is to provide adjustable means for facilitating the tuning operation of the above described vibratory systems and to secure said means in position when resonance is obtained.

Further objects and features of the invention will appear from the following description with reference tothe accompanying drawings which show embodiments of the invention by way oi example only and in which:

Figure 1 is a front view of a razor blade shaver with the cover of the handle shaped casing'removed, part of the mechanism being shown in section.

Figure 2 is a side view of theshaver shown in Figure 1, showing the casing in section.

Figure 3 is a view of part of the mechanism shown in section and takenv on line 2-2 of Figure 2.

Figure 4 is a front view of a'clipper or dry shaver form yof mechanism and Figure 5 is a side view in half section of the mechanism shown in Figure 4. l

A pair of leaf springs when xed at one end and connected together at the other end, for example, by a cutting device can be vibrated by an alternating current energised magnet the poles of which face one of the leaf springs provided' the spring is of magnetic material or is provided with an armature of such. material.

When the electro-magnet in the above described arrangement is energised by alternating current the armature will be attracted to and repelled from the poles of the magnet at a frequency of reversals depending upon` the frequency of the alternating currentsupply source. Such action will cause a slight movement of the leaf springs andof the cutting device but due to the inertia of the parts this is generally insuflcient to move the cutting implementso as to improve the cutting action thereof `to an appreciable extent. If, however, the natural period of vibration of the mechanical system coincides with the frequency of the alternating current the system will move in resonance therewith as the result of which the amplitude of movement of the cutter is greatly increased and an exceedingly eiective cutting action is obtained.

The design and construction of appliances according to the invention presents considerable diiiiculties principally due to the dimculty in mathematically determining the natural period of vibration of leaf spring supported systems such as the different types contemplated by the invention.

As the result of experiments it has, however. proved possible to design leaf spring supported mechanical systems so that they can be made to resonate with 50 cycle alternating electric current. If the frequency of the alternating current is 60 cycles the springs must be stiffer or shorter or alternatively the loading must be lighter. On the other hand if the frequency is 25 cycles the springs must be more resilient or longer or the loading may be heavier.

In the construction of appliances according to the invention the dimensions and quality of -the leaf springs are proportioned to the mass of the cutting device and its mounting means, if any, and of any other part carried by the springs so that the natural period of vibration is approximately the same as the frequency of 50 cycle alternating current.

Owing to unavoidable differences in materials. manner of securing the springs and like causes it is not convenient to produce the appliances so that their characteristics are exactly identicaland according to a feature of the invention an adjustable tuning device is provided by which means the system can be tuned to resonate with the alternating electric current without dimculty and when resonance is obtained the tuning device is fixed in position.

In order to facilitate manipulation by hand the above described arrangement is mounted in a casing in the form of a handle in which the leaf springs are rigidly secured at one end the cutting implement being disposed outside the casing so that the cutting edge or teeth are convenientlyA disposed for application to the beard or hair.

Referring to the drawings and to Figures 1, 2 and 3 in particular, numeral 2 denotes a metal or composition moulding or the like forming the casing for the mechanism of the shaver and) is a lid capable of being secured thereto so as to constitute with part 2 a handle shaped casing convenient in size for holding in the hand.

Lead springs 4 and 5 are anchored in the bottom of casing 2 by a spacing piece 6 and are.

secured to the casing by a bolt 1 having a nut 8 which bolt passes transversely through the casing and clamps the casing as well as the spring iirmly. Springs 4 and 5 are of good quality spring steel and are between 2 and 3 inches long in the construction shown in the drawings being 1/2y wide and .020" thick. Spring Ii is provided with a plurality of magnetic material laminations 9 secured thereto by rivets or the like 50 so as to constitute the armature of an electromagnet the core III of which is secured in casing 2 by screws, bolts or the like. 'I'he energising winding II of the electro-magnet is 'connected to a twin electric cable I2 which passesthrough a rubber or like material gland |3 adapted to be clamped between casing 2 and lid 3.

The pole pieces of core I are spaced from the armature 9 so that forced vibrations do not holes being engaged by correspondingly shaped pins I9 fixedly secured in legs Il and I4.

The mechanism also. incorporates a blade edge guard and holder comprising a ilat plate portion 2li from which a comb guard provided with teeth i0 2| is bent up as indicated in Figures i and 2.

The guard is also provided with end lugs 22 whereby the guard is pivotally secured to frame legs I and I6. The end lugs 22 are provided with hooks or claws 23 adapted to engage the ends of the blade edge so as to retain the blade edge and the guard teeth 2| in the position in which an eilective cutting action can be obtained with the edge with a comparativelyy small risk of accidental cuts in accordance with the known safety razor guard principles.

In order to permit strapping .of the edge of blade Il. the blade guard is provided with a manipulating handle 24 whereby the guard can be manipulated to free the hooks from the edge 25 of the blade and the lugs 22 are provided with cam surfaces 25 arranged so that when the hooks are clear of the blade, cams 25 push the blade forward approximately into a horizontal position in the case of the mechanism shown in Figure 2.

Upon release of handle 24 the hooks 23 are spring urged against the side of the blade causing the same to be further rotated into a practically vertical position in the case of the mechanism shown in Figure 2 and the blade can in this position be inserted between strapping rollers or the like for the purpose of sharpening the edge and after the sharpening operation the blade I1 is pressed forward with the fingers causing the guard to pivot upon its support and to recede until hooks 23 snap over the ends of the blade edge after which the sharpened blade is in position for further use.

Referring to Figure 3 the pivotal support for the blade guard is shown as comprising a tube 26 to which lugs 22 are rigidly secured at the Leg I8 is provided with a pivot .pin 21- ends. xedly secured therein onto which one end of tube 26 fits with what may be termed sliding iit. Leg I I is provided with another pivot pin 23 in which is formed a groove 29 and from which extends a reduced diameter portion 30 upon which a spring 3| is mounted the end of which passes into groove 23. To obtain anchorage for the other end 34 of the spring an element comprising a portion 32 having a sliding fit in tube 26 and a reduced section portion 33 is provided. The end 34 of spring 3| rests in a groove 3S in part 32 and a recess 36 is also produced therein into which a tongue or punched out projection on tube 23 is forced whereby parts 32 and 33 are rigidly secured in the tube to form a guide and anchorage for the end of spring 3|.

Spring 3| is so arranged thattension can be applied thereto by pivot pin 28 to force hooks 23 into engagement with blade I`|l with a precause the armature to strike the poles as this 10 the action 0f the edge guard previously described would cause chatter or noise which is highly objectionable in shavers during application to the face. y

The cutting mechanism of the shaver shown in Figures l, 2 and ilv incorporates a U shaped 75 ures 1 and 2, and substitution of another blade,

1n order to facilitate removal of bladen, m-

` same time serving to secure leg I to bar leg i6 is resiliently secured to bar I4 by means of a pin 39 having a head 39 the arrangement as shown in Figure 1 being such that al spring 40 resting against head 39 and against a reduced portion of an orince 4I in bar I4 tends to retain pivot pins I9 firmly forced into holes I8 in blade I'I. By pulling leg I9 against the action of spring 40. pins i9 can be withdrawn from holes I9 whereby blade Il is freed, pivot pin 21 (Figure 3) being pulled somewhat out of I4 in a rigid manner.

The mechanism described above will vibrate when magnet II (Figure 1) is energised with 50 cycle alternating current but experience shows that it is extremely diilcult to ensure that springs 4 and 5 when mounted and loaded with 'the mechanism in the manner described above will necessarily have a natural period of vibration of 50 cycles per second which is necessary in order that the system may resonate when magnet II is energised. To overcome this dimculty springs 4 and 5 are made slightly longer than is necessary for obtaining resonance under the conditions described and an adjustably mounted tuning element 43 is forced between spring 4 and the side of casing 2 and is adjusted until the springs, when loaded as indicated, vibrate in resonance with the alternating electric current. Resonance is obtained when springs of the dimensions described and-mechanism of the proportions with respect to the springs shown in the drawings are adopted. Tuning operation is very easily carried out by sliding element 43 up and down and when the system is not in resonance a comparatively slight movement is imparted to the blade Il but as soon as resonance is approached the amplitude of vibrations increases to a very pronounced extent and further movement of element 43 will again cause the system to be thrown out of tune after which the vibrations will again become of very restricted amplitude. Normally the distance over which the element 43 can be moved is of the order of 54;" and the exact tuning point is obtained by selecting the centre of the distance over which reso-v nance appears to be obtained. When this position hasl been determined holes are produced in the bottom of casing 2 and in lid 3 so that y element 43 will be rmly held in position when the lid 3 is secured to casing 2 by screws or other suitable means.

The application of the invention to hair clippers or devices known as dry shavers is shown in Figures 4 and 5. Springs 4 and 5 in this case are secured together at the free end by a distance bar or piece 50 secured to the springs by rivets or the like 5I the ends of springs 4 and 5 projecting a short distance above the top of bar 50 as shown in Figure 4.

The cutter 52 is T shaped and is secured by means of fairly rigid struts 53 to beads 54 upon casing 2 the cutter and struts being rigidly secured together by rivets or the like 55. The cutter is provided with ne teeth 56 with which a movable U shaped cutter 51 provided with teeth 58 cooperates.

As shown in Figure 4 movable cutter 51 nts 3 between the ends of springs 4 and 5 and a pair of springs 59 housed in holes 99 in barili are arranged to push the teeth 58 of the movable cutter 51 onto the teeth 56 of the lstationary cutter 52. l 'I'he magnetic system as well as the mounting casing for the mechanism shown in Figures 4 and 5 are identical to that shown in Figures l and 2 and it will be appreciated that when springs 4 and 5 loaded as indicated in Figures 4 and 5 are tuned to'resonate with the alternating electric current the teethof the movable cutter will reciprocate with respect to the teeth of the stationary cutter and will produce a clipping action which, as is known, can be utilised for shaving provided the teeth 56 are sufilciently fine.

The electro-magnetic system of the present invention is of extreme simplicity and experience indicates that by obtaining `resonance of the mechanical vibratory system with the 'energising current amplitudes of movement of the cutting device of up to Mg" are easily obtainable. In the case of blade shavers such movement is actually not desirable and a movement of the order of 35nd" is preferred but it will be understood that this is somewhat reduced when the blade is applied to the face. Stopping of the blade by contact'with the face is not possible provided the system resonates and an exceedingly effective cutting action is obtained by the blade shaver shown in Figures 1 and 2.

In clipper or dry shaver devices of the kind shown in Figures 4 and 5 it is highly desirable to obtain movement in excess of a space corresponding to the width of a. tooth upon the movable cutter as well as the space between adjacent teeth and owing to the liability to reduction in amplitude of vibration a somewhat more powlerful electro-magnetic system is required for dry shavers than is necessary for blade shavers.

By reducing the weight carried by the springs 4 and 5 an increase in amplitudeis obtained and for this purpose the spacing bar 50 is preferably of light metal alloy and moreover the section of cutter 5l is reduced to the minimum necessary for adequate mechanical rigidity and in thisl manner amplitudes of the order of 5/8". are obtained such amplitude being reduced to about half when cutting through sti beard or dense hair but under normal practical conditions the clipping action remains effective under ordinary clipping and shaving conditions.

The appliance has exceptional advantages over rotor actuated appliances for `use as a power unit in shavers and hair clippers owingto its extreme simplicity, absence of mechanical mechanism and frictional eiects. Moreover it is silent in operation and extremely durable whereas the appliance lends itself to production upon a large scale at low cost compared with other forms of power units for similar purposes.

Various changes may be made in the speciiic embodiments of the invention herein described without departing from or sacricing the advantages of the invention as dened in the appended claims.

I claim:

1. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system comprising of a pair of leaf springs positioned in spaced relation, one on each side of said electromagnet. a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a cutting` device attached to the other ends of said leaf springs. an armature disposed centrally on one of said leaf springs between said base and said cutting device so as to face the poles of said electromagnet. said leaf spring supported vibratory system as a whole beingarranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

2. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet. said vibratory system consisting of a pair of leaf springs positioned in spaced relation, one on each side of said electromagnet, a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a cutting device attached to the other ends of said leaf spring, an armature consisting of a plurality of laminations of magnetic material disposed centrally on one of said leaf springs between said base and said cutting device so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural' period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained. s

3. A cutting appliance comprising: an alternating electric current electro-magnet, a leaf spring vibratory system for said electro-magnet, a supporting base for said leaf spring vibratory system. means for fixing one end of said leaf spring vibratory system to said supporting base, a cutting device attached to the other end of said leaf spring vibratory system. an armature disposed centrally on one of the leaf springs of said vibratory system between said base and said cutting device so as to face the poles of said electro-magnet, said leaf spring vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained and means for tuning said vibratory system by lengthening or shortening the e'ective vibratory portion of one of the leaf springs of said vibratory system.

4. A cutting appliance as set forth in .claim 3, having means for permanently fixing said tuning means after the vibratory system is tuned.

5. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system consisting of a pair of leaf springs, a supporting base for saidleaf springs. means for fixing one end of each of said leaf springs to said supporting base, a spacing member attached to the other ends of said leaf springs, a cutting device attached to said spacing member, an armature 'disposed centrally on one of said leaf springs between said base and said spacing member so -as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

6. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for'said electro-magnet, said vibratory system consisting of a pair of leaf springs, a supporting base for said leaf springs, means forfix'ingoneendofeachofsaidleafspringsto said supporting base. a spacingmember attached totheotherendsofsaidleafspringaalegmember rigidly attachedtoone end ofsaldspacing of said leaf springs between said spacing meinberand saidsupportingbasesoastofacethe poles of said electro-magnet. said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

tory system consisting of a pair of leaf '1. A cutting appliance comprising: an alien nating electric current electro-magnet. a vibratory system for said electro-magnet, said vibrasprings, a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a spacing member attached to the other ends of said leaf springs, a leg member rigidly attached to one end of said spacing member, another leg member resiliently secured to the other end of said spacing member. a razor blade pivotally supported between said leg members, an armature disposed centrally on one of said leaf springs between said base and said spacing member so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

8. A lcutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system consisting of a pair of leaf springs,`

a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a spacing member attached to the other ends of said leaf springs, a leg member rigidly attached to one end of said spacing member, another leg member resiliently secured to the kother end of said spacing member, a razor blade pivoted to said leg members, means for limiting the pivotal movement of said lrazor blade, an armature disposed centrally on one of said leaf springs between said base and said spacingmember so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

9. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system consisting of a pair of leaf springs, a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a spacing member attached to the other ends of said leaf springs, a leg member rigidly attached to one end of said spacing member, another leg member resiliently secured to the other end of said spacing member, a razor blade pivoted between said leg members, a guard for said blade edge, spring urged hooks for said guard, said hooks being adapted to engage the ends of said blade edge, an armature disposed centrally on one of said leaf springs between said base and said spacing member so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electromagnet so that resonance, is obtained.

10. A cutting appliance as set forth in claim 9 having pivot pins secured to said leg members for supporting said guard, and a spring attached to one of said pins and to said guard for normally urging said guard hooks into engagement with the ends of said blade edge.

11. A cutting appliance as set forth in claim 9 having pivot pins secured to said leg members for supporting said guard, a spring attached to one of said pins and to said guard for normally urging said guard hooks into engagement with the ends of said blade edge, finger actuated means for disengaging said guard hooks from said blade edge, and cam means for moving said blade about its pivots.

12. A cutting appliance as set forth in claim 9 having pivot pins secured to said leg members for supporting said guard, a spring attached to one of said pins and to said guard for normally urging lsaid guard hooks into engagement with the ends of said blade edge, nger actuated means for disengaging said guard hooks from said blade edge, and means for moving said blade on its pivots into stropping position upon release of said finger actuated means.

13. A cutting appliance as set forth in claim 9 having pivot pins secured to said leg members ior supporting said guard, a spring attached to one of said pins and to said guard for normally urging said guard hooks into engagement with the ends of said blade edge. linger actuated means for disengaging said guard hooks from said blade edge, and means for moving said blade on its pivots into stropping position upon release of said finger actuated means and back into engagement with said guard hooks by the application of nger pressure to said blade.

14. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system consisting of a pair of leaf springs, a supporting base for said leaf springs, means for fixing one end of each of said leaf springs to said supporting base, a T-shaped hair clipper cutter supported over the free ends of said springs, a Ushaped sliding cutter associated with said T- shaped cutter and attached to the free ends of said springs, an armature disposed centrally on one of said leaf springs between said base and said Ushaped cutter so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that resonance is obtained.

15. A cutting appliance comprising: an alternating electric current electro-magnet, a vibratory system for said electro-magnet, said vibratory system consisting of a pair of leaf springs. a supporting base for said leaf springs, means for iixing one end of each of said leaf springs to said supporting base, a spacing member attached to the other ends of said leaf springs, a Ushaped cutting device, a T-shaped cutter carried by said supporting base and associated with said Ushaped cutting device, spring means carried by said spacing member and engaging said Ushaped cutting device for pressing it into engagement with said T-shaper cutter, an armature disposed centrally on one of said leaf springs between said baseI and said spacing member so as to face the poles of said electro-magnet, said leaf spring supported vibratory system as a whole being arranged to have a natural period of vibration substantially coinciding with the frequency of the alternating current energizing said electro-magnet so that. resonance is obtained.

16.A cutting appliance comprising: an electro-magnet adapted to be energized by pulsating electric current having a denite frequency, a cutting device, a vibratory system actuated by said electromagnet, said vibratory system consisting of a leaf spring for substantially floatingly supporting one end of said cutting device and for driving said cutting device, a supporting base for said leaf spring, means for rigidly fixing one endA of said leaf spring to said supporting base, said vibratory system including additional supporting means for ilexibly and substantially iloatingly supporting the other end of said cutting device on said base, and an armature disand said cutting device as a whole having a natural period of vibration substantially coinciding with the frequency of the pulsating current energizing said electro-magnet so that resonance is obtained.

HARRY BECKHAM RANDQLPH.

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