US2664884A

US2664884A - Scalp massaging device

Info

Publication number: US2664884A
Application number: US125865A
Authority: US
Inventors: Verne Albert A La
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-11-07
Filing date: 1949-11-07
Publication date: 1954-01-05
Anticipated expiration: 1971-01-05

Description

Jan. 5, 1954 A. A. LA VERNE SCALP MASSAGING DEVICE 4 Sheets-Sheet 1 Filed Nov. 7, 1949 n I mm N V E a mL A. W h 6 M M A Y B 0 4 m.. 2 a \Q "7. LP: \J

A I/arneys Jan. 5, 1954 LA VERNE 7 2,664,884

SCALP MASSAGING DEVICE Filed Nov. 7, 1949 4 Sheets-Sheet 2 -iil' Allliilfi v INVENTOR. Albert A. La Verne Attorneys Jan. 5, 1954 A. A. LA VERNE SCALP MASSAGING DEVICE 4 Sheets-Sheet 3 Filed Nov. 7, 1949 INVENTOR. Al berr A. La Verne Attorneys Jan. 5, 1954 A. A. LA VERNE SCALP MASSAGING DEVICE 4 Sheets-Sheet 4 IOB Filed Nov. 7, 1949 INVENTOR. Albert A La Verne Attorneys Patented Jan. 5, 1954 UNITED STATES PATENT OFFICE SCALP MASSAGIN G DEVICE A b t A. La Ve Bro-ck n, N X- Application November 7, 1949, Serial No. 125,865

This n nt on rel tes to d ice :fo nah u t n the h m n scal and s part cularly 0. 1 ear ed w h devices for massa in st ch he, loosening and l va i v the cal and, V er stimu lating the skin thereof as well as the roots of h h r, thereby p mot ng cir ula on nd imp c -lns the on it ons n cessa y for he mainienance and gr w h of the ha r- By way of introduction, it may be stated that e i e t c use i t e maj cases of P e a re l o ha r is th t ghtenin of t scalp around the rigid bony structure of the skull. This tightening is a pathological process usually starting in a small or restricted area requiring many months to years to develop but eventually afiecting the scalp in its entirety.

The pathological tightening of the scalp con stitute's part of a vicious cycle. The initial tightening in a given area produces in addition to the progressive loss of hair a compressive type of circulatory obstruction to the affected area, and eventually to distal areas which have circulation that is subsidiary to the initially affected area,

thereby reducing the nourishment to the hair roots and particularly to the secretory glands. This in turn results in desiccation, reduced pliability, atrophy, scarring and eventual shrink-age of scar tissue, and this process produces in its turn further tightening and an involvement of constantly increasing areas. The process is progressively aggravated and intensified by the gradual increase in the size of the skull, being severest in the areas where the scalp is stretched most tightly, namely at the promontories or acute 'angulations of the skull, which are usually at the temporal and occipital areas of the skull. The male skull increases to a greater extent than does the female skull, which accounts in some measure for the fact that premature loss of hair is more common among male adults than among ma es- T e m ni ul tion o e s alp so as to p mote, hair growth may be carried out either manually or mechanically. Manual manipulation, 1. e. the use of the hands and fingers, requires the expenditure of so much energy and has such a tiring effect on the operator that it is e c e n difficu t a d in m st c s impractical.

There have b e many att p s to man pu ate th s alp b means of hand operated and me actuated massa e devices but none have fulfilled the necessary use requirements or have achieved degree of consumer acceptance orcomln c l su ces rior art massagin devices were eith r incapable of producing the necessary manipulation hi the scalp o ser ed to appl the reat Pressure to he calp.- The scalp wi its appe da is a h hly eem ieated ph sie lo ica Qrean, consist n s it d es o deliea st uc u es in luding nerv s, b eed ess l ands hair roots, fibrous and connective tissue, fat-and mus le t ssue, and any de ice int nde to me sage the scalp must be so constructed as to carry out i s function withou au n a y inju y thereto.

he pri ary ob ect of the p e ent in en -i91 is to provide a device for manipulating the urnan scalp so a to main ain and p o ote hai er w Without causing injury to the delicate structure e eof- Ane er imp e t je is to a cade scalp manipulating device which is of relatively si 1e, inexp nsiv r gged co t uc on and W131 is Capable 0f ing used i the er eet ar its intended u p se by t ep tient hims lf or by an operator.

A other object f im ortan e is o Pre is e scalp manipulating device capable at producing a very vigo us but neverth less ent massage action by the app ication of a surpris n y smal mou t o effort o the art, of th ope ato Another Obi -ct of the i v ntio t provide a sca p manip at s dev ce which ca he used to ma a e s etc l osen, l e brus and flush h calp, o or o of th se f ctions bein carried out sep ra l o s m ltaneou ly.

Another impor an Object is to provide a r call massaging device consisting of a relat ely few units and e ments. hi h an be readil asfimbled o disassembl d y per ns havin lit mechanical skill, which is Wholly sanitary and which can be easily kept clean.

A further o ject is t p e a m ss e de ice wh h an be r a ily ad usted to .fit a w d o head sizes an shapes of ku ls nd which can be ad ust d w hin fairly wi limit in exert a cle. reci am unt oi press re on the sea s- The und lyi g a d di ect ng conce r the invention is usceptible of b in embod ed a variety o m hanica cons ruc ions broadest essential details, the device pi the in.- enticn comprises th e rin ipal parts, We massage units of identical constructien a onne t ng yoke the massage unit bein detac a ly and adilist ly conne ted o he extr i ie of the yoke, which serves to held the massa e un s esether ier mul aneous and mo ies th n cessary p e su e for e e tive oper ti n invent on will n w e desc ibeslca ticular referen e to two pre ently re erre em 3 bodiments thereof. Referring briefly to the drawings:

Figure l is a plan view of one of the presently preferred embodiments, showing the device applied to the head of a patient, the outline of the head and the hands of the operator being in broken lines;

Figure 2 is a side elevation, the outline of the head and of the upper part of the face being shown in broken lines;

Figure 3 is a vertical cross-section through one of the massage pads, showing its attachment to the massage unit;

Figure 4 is a cross-section taken on line 4-4 of Figure 3;

Figure 5 is an end view of one of the massage units;

Figure 6 is a view illustrating the method of adjustin the position of a massage pad on the massage unit, the final adjusted position of the pad being shown in broken lines;

Figure 7 is a perspective view of the adjustment element of a massage pad;

Figure 8 is a view illustrating the method of removing the massage units from the connecting yoke;

Figure 9 is a cross-section taken on line 9-9 of Figure 3;

Figure 10 is a cross-section taken on line III-4 D of Figure 1;

Figure 11 is a cross-section taken on line I l-l I of Figure 1;

Figure 12 is a cross-section taken on line I2I 2 of Figure 11;

Figure 13 is a front elevation of a second preferred embodiment, shown in relation to the head;

Figure 14. is a plan view, one of the massage pads being shown in cross-section; and

Figure 15 is a side elevation, the massage units being shown detached from the yoke member.

Referring to Figures 1 to 12 of the drawings with greater particularity, it will be seen that the device of the first embodiment consists essentially of three principal parts, the massage units I and 2 and the connecting yoke 3. The yoke 3 serves to connect or hold the massage units to gether for simultaneous use, and provides the necessary pressure for effective operation. The massage units, which are of identical construction, are detachably and adjustably connected to the extremities of the yoke in the manner to be hereinafter described, and may be used separately and individually as will also be described.

The yoke 3 consists of two fiat

metallic strips

5 and 6, pivotally connected by means of a pin I, and bent into a generally arcuate shape. Hooks 8 and 9 are provided approximately midway between the ends of the strips. Secured to said hooks are the tension springs In and I l Threaded studs I2 and I3 are secured to the inner ends of the springs, one of said studs being provided with a right-hand thread and the other being provided with a left-hand thread. The numeral I4 designates a suitable threaded knurled hand nut which engages the threaded adjacent ends of the studs I2 and I3, as in the conventional form of turnbuckle.

It will be understood that when the hand nut I4 is rotated in one direction the springs are drawn toward the hand nut, thereby increasing the pressure exerted on the extremities of the yoke 3, and that when the nut is rotated in the opposite direction the springs are gradually loosened thereby decreasing the pressure on the extremities of the springs. The springs are proportioned to exert a maximum pressure of approximately 30 pounds when the device is mounted as shown in Figures 1 and 2 on a head of normal size.

The yoke 3 may be advantageously, and preferably is, encased in a housing I 5 in order to prevent the hair from becoming entangled in the springs when the device is being adjusted on the head. The housing is made of a fiat sheet of suitable material such as plastic, which is bent, as shown in Figure 1, to form a top 58, a bottom I! and a front wall [8. The edges or" the blank are cut to conform to the curvature of the yoke, as shown in Figure 1. A rectangular slot 13 is cut in the top I6 of the housing and an aligned slot 20 is cut in the bottom I T of the housing. The knurled periphery of the hand nut I protrudes through these slots so that it may be adjusted. These slots are elongated to allow for the linear movement of the hand nut, which cccurs during its adjustment. Compare Figures 1 and 8. The housing is secured to the yoke only at the pivot pin 1', and is held against rotation by the projection of the hand nut I4 through the slots I9 and 2!]. The front wall l8 extends somewhat less than the full length of the shield in order to permit the inward movement of the outer ends of the yoke 3 as shown in Figure 8.

The outer ends of the

metallic strips

5 and 6 are provided with the forwardly projecting fiat portions 2| and 22. To these flat portions are welded or otherwise suitably secured the

tubular bearings

23 and 24. In these hearings are rotatably mounted the

rods

30 and 3! respectively. The rods may be kept from axial movement by the

shoulders

32, 33 and the retaining

nuts

34, 35. The outer end 30a of the rod 38 is bent at and the outer end He of the odd 3! is bent similarly, for a purpose to be hereinafter pointed out.

The two massage units l and 2 are detachably secured to the yoke 3 by means of the rods 39 and 3! respectively in the manner to be described. These units are of identical construction, and hence a description of the unit 2 will suffice for both.

The unit 2 is shaped, as shown in Figures 1, 6 and 8, substantially like the combined transmitter-receiver of the French type of telephone instrument, i. e. like an elongated letter C. The central elongated portion, which is designated by the numeral 40, constitutes the handle as in the case of the telephone instrument, and terminates at each end in the inwardly projecting boss 4!. The two units are normally mounted on the

rods

30 and 3| with their bosses facing each other.

The central handle portion 40 is provided with a slot 42 cut in its outer periphery and extending from about the middle of the rear end thereof. As a result the rear half of the handle portion is substantially channel shaped in cross-section as shown in Figure 10. The vertical leg of the channel is denoted by 43 and the two end portions by 44 and 45. A hole 46 is provided in the lower end portion 45 at the center of the handle 40. Said hole is provided with a bushing 41, which is chamfered at its upper end as shown at 48. The reference numeral 50 denotes a slot which is cut in the upper end portion 44, starting directly above the hole 46 and extending forwardly and outwardly to form an obtuse angle with the groove 42.

As shown in Figure 1, the two massage units 1 and 2 are normally mounted on the

rods

30 and 3| with their corresponding bosses 4I facing each other. The .rods 13.0 and 1| :arereeeived within the slot 42 of the .eor'responding 4 .or 2, with the bent end a :or Me received in the bushing 41 in the hole 46.. The eham'fer 4 8 in the upper portion :of the bushing provides clearance for the radius of the bend .in the rod. The :unit is locked against removal from the mod, but the unit may be rotated with the rod 30., 3| in the

tubular bearing

23, 24. When the unit is turned through 180 (from the position in dot and dash lines to the one in solid lines in Figure :8.) and only then, the slot permits the removal of the bent portion 31a of the rod 31 from the bushing 41 so that the unit may. be disconnected from the rod.

It is thought to be clear from the foregoing description that to attach the unit .2 to the rod 31, the unit 2 is held in the position shown in solid lines in Figure 8, the lower portion of the rod '31 is inserted in the slot 50, the bent portion 3|a is inserted into the bushing 41., and the unit is rotated about the portion -.-3|-.w to the dotted position so that the rod 31 is received in the slot 42. As long as the unit 2 is held in the position shown in dot and dash lines in Figure 8, the unit is locked against removal from the rod, but it is free for rotation with the rod in the bearing 24 and also rotatable in the bushing 41 in all positions intermediate the two positions in Figure 8.

It will be noted from an inspection of -Figure 1 that the slot 50 in unit 2 is on the top side of the unit whereas in unit l, the slot 50 is on the bottom side. This is due to the fact that the units are of identical construction are arranged on the

rods

30 and 3| so that the massage pads face each other. If considered desirable, the units may be made so that they are mirror images or counterparts of each other, in which case the slot '50 in both units will be on the same side.

The unit 2 is adapted to carry two spaced massage pads, each "one of which is denoted by the reference numerals 5|, in such manner that they may readily be adjusted in reference to the unit as well as to its mate. The pads are of identical construction, and hence only one need be described. Before doing so, it is to be noted that the inwardly projecting boss 4| terminates in a rectangular block 52. The reference numerals 53 denote a vertical slot which is formed in each outer end of the units, extending through the bosses 4| and the terminal blocks 52. Looking from either end of the unit 2 (see Figure 5, and

also Figure 3), it will be seen that the slot has a symmetrically curved upper portion '54, a restricted intermediate portion 55, and a relatively Wide lower portion 56. The portions 54and 55 a're joined by a smooth curved surface 51. The vertical walls or sides of the lower portion 56 of the slot are denoted by 58 and 59. In each of these walls or sides are cut or formed a plurality of teeth 60 for a purpose which will hereinafter appear.

The massage pad 5| has for its body portion a vided inits center wtih a-rectangular aperture 65,

through which is adapted to .pass the elastic finger orstemfl. Thereferencenumerals-BB and 61*denotetwoprojections on the upper surface of the block; one'on'each long side of the aperture. A numberof teeth 68 is formed on the sides of the projections away from the apertures. These teeth are proportioned so as to cooperate with the teeth =60 previously described.

Thacup-shaped-element 6| is secured to the positioning block-64 "in the manner shown in Figures 3, 4 :and fi. The positioning block rests on the-convex side of the cup-shaped element 6 l the fingerbr stem 62 passing through the aperture 65 in the block. The cup-shaped element is shown as having two covers, an inner one 69 detachably secured by means of an elastic band 10, andanbuter one secured by means of an elastie band 4-2. Both-covers may be of fabric, but the outer one is preferably of an inexpensive readily disposable material such as paper or gauze, for sanitary reasons. One or both covers may be of asoft material such as velvet, velveteen, mohairgplush, or other fabric having a pile. This type of material is preferred for the reason that when applied under pressure and rubbed against thescalp for-several minutes, itserves to produce a maximum gripping action and minimum irritation. As shown in Figures 3 and 5, the elastic band 12 secures the outer margins of the outer cover 1| about the circumference of the positioning block 84.

The manner in which "each massage pad is adjustably secured to one of the massage units is shown in-Figure =6. As shown in said figure, the

.. massage unit 1 o 2 is held in one hand by means of the handle portion 40, and the pad 5-! is held by the fingers of the other hand. The ball 63 on the elastic resilient finger 62 is inserted in the roove 53 so that it rests on the eurved lower surface 51 of the upper portion 54 thereof, and then the finger 62 is stretched and drawn into the communicating portion 55 of the groove, bringing it into the position'illustrated. The tension on the finger 152 is then relieved'so that the pad isdrawn up against the terminal block 52 of the boss 4| with the teeth 51 of the positioning block 64 in engagement with the teeth -60 in the terminal block 52 (see the position in dotted lines). The pads 5| may be readily adjusted inwardly or'outwardly with respect to the handle of the massage units by stretching the finger B2 and moving the :pad the desired amount in the desireddire'ction. The tension in the fingerBZ keeps the pads locked in adjusted position.

It is important to noted that the bosses 4| on the ends of the handle portion '46 are not parallel but are in converging relation to each other. Hence the pads are in angular relation to each other, conforming generally to the average human skull so as to produce a close fit. The adjustability of the pads and the inherent flexibility of the body portion 5| of the pads take care of diller'ent head sizes and any irregularities of "shapes. As has been stated, the springs in the yoke -3 are proportioned to exert a maximum pressure of about 30 pounds when the device is mount-ed on a head of normal size as shown in Figures 1 and 2, and that by rotating the hand nut 14 the pressure i'nay be varied.

It is believed that the manner 'of using the device for its intended purpose can be readily understood from the foregoing description of its structure. However, a brief explanation will be given as to the presently preferred manner of The device is positioned on the head of apatient as shown in Figures 1 and 2, the desired degree of pressure being applied by means of the hand nut I4. The operator grips the handle 42 of a unit in each hand, and proceeds to massage the scalp by pushing and pulling on the two units so that the scalp is not merely moved but is actually stretched. To cover the entire scalp, the manipulation is performed first by means of relatively slow full strokes horizontal to the skin surface in one direction, and then in the opposite direction. The two units are then moved up and down with slow full strokes to elevate and lower the scalp, and finally the two units are manipulated with a rotational movement first clockwise and then counterclock-wise. The device, it will be understood, can be manipulated over practically the entire head, and because of the manner of connection of the massage units to the yoke, the massage units remain in continuous contact with the contour of the skull.

At various times during the manipulation, the relationship of the massage units to the skull may be changed. In the drawings, the massage units are shown as being positioned at the sides of the skull on the same level. The units may be positioned in other relationships. For instance, the two units may be positioned at dilTerent levels of the skull either at the sides or at the front and rear thereof.

Referring now to the embodiment shown in Figures 13, 14 and 15, it will be seen that said device consists essentially of a yoke or spring frame I and the two massage units I02 and I03. The yoke or spring frame consists of a strip of flat spring steel I04 in the form of an inverted U, having the normally horizontal middle portion I05 and the two downwardly projecting legs I06 and I0! substantially at right angles to said middle portion I05. Secured to the upper surface of the horizontal portion I05 by means of two machine screws I08 is a strip I 09 of steel or other suitable material to reenforce the horizontal portion and to render it rigid. The screws I08 pass through holes in the strips I04 and I09 and are received in the threaded holes in blocks H0. The reenforcing strip is preferably slightly shorter than the horizontal portion I05, the screws I08 secure the ends of the strip I09 to the horizontal portion, and the blocks III! are spaced a short distance inwardly of the vertical legs I05, I01 Each of said legs is provided near its juncture with the horizontal portion I05 with a screw-threaded stud III, the outer end of which is provided with a knurled hand nut H2 and the inner end of which bears against one of the blocks IIO. A suitable aperture is provided in each of the legs I06, I01 to receive the studs III. It will be understood that the studs III and the hand nuts I12 constitute means to separately change the angles between the legs I06, I01 and the horizontal portion I05 of the U-shaped element IOI, thereby separately adjusting the pressure of the massage units against the skull to be massaged. The reference numerals H3 denote short flat metal strips to reenforce the legs I06, I01 in the area of the studs and to distribute the pressure caused by tightening the nuts H2. The strips II3 are each provided with an aperture to receive the stud I I I.

The lower end of each of the vertical legs I06, I0! is provided with means to detachably secure thereto one of the massage units I02, I03. Referring to Figure 15, it will be seen that said means consists of a tube H4 secured to the lower end of the leg, and a pin I I 5, secured in said tube and projecting to one thereof. In Figure 15, the tube H4 is shown as being secured to the right hand side of the lower end of the leg I07 and the pin I I5 is shown as projecting to the left. It will be understood that in the case of the leg I06, the tube H4 is secured to the left hand side of the lower end of the leg and the pin II5 projects to the right.

Each of the massage units I02, I03 consists essentially of a fiat strip I20 of metal bent into arcuate form, a handle I2I secured to the middle of said strip on the outside convex surface thereof, and a massage pad I22 detachably and adjustably secured to each end of said arcuate strip. The strip I20 may be either of rigid or flexible material, the fiexible material having the advantage that it can be readily bent to fit the skull to be massaged. One of the massage units is righthanded and the other is left-handed, but otherwise they are identical. As shown in Figure 15, the arcuate strip I 20 is provided at the middle just above the point of attachment to the handle iZI with a short horizontal tube I23 adapted to i receive the pin I I5 previously referred to, thereby securing the massage unit 03 to the leg I 01. The other massage unit I02 is secured to the leg I06 in a similar manner, the only difference being that the tube I23 on said unit is at the right instead of the left. The pin II5 may be locked in place by means of a pivotally mounted short strip of metal I24. A nut I25 constitutes means to tighten the pivotal connection so as to secure the strip I 24 in looking position.

The massage pads I22 are of identical construction, the detailed construction being shown in the cross-sectional part of Figure 14. Each pad has for its body portion a shallow cup-like member I26 of an elastic resilient material such as rubber, which is supported and reenforced by a metal backing element I21. The backing element is secured to the body portion of the pad by means of a long screw I28 which passes through aligned apertures in both the body memher and the backing element, and a nut I29. The screw I28 extends beyond the nut I29 and is adapted to receive a knurled nut I30. The pad has a permanent cover I3 I, which may be of elastic or padded material, and an outer cover I32 of inexpensive, readily disposable material such as paper, gauze, etc.

The arcuate member I20 is provided with two longitudinal slots I33, one on each side of the handle I2I, to provide means for detachably and adjustably securing the pads thereto. The pads are secured to said member by passing the ends of the screws I28 through the slots I33, positioning the pads in the desired relationship, and then securing the pads to said member by placing the knurled nuts I30 on the screws and tightening said nuts. A washer I34 may be interposed between the arcuate member and the knurled nut. The portion of the screw I 28 beyond the nut I29 may advantageously be rectangular in cross-section so as to fit in the slot I33. An aperture I35 is shown as being provided in the arcuate member at about the middle thereof for a purpose which will be later pointed ou The second embodiment of the invention may be used in substantially the same manner as explained for the first embodiment. In the case of both embodiments, one or both massage units may be removed from the connecting yoke and used separately or simultaneously to massage the 9 scalp. In the case of the second embodiment, a single massage pad may be secured to the middle of one of the arcuate members I20 by means of the aperture I35, the long screw I28 and the nuts I29 and I30, and manipulated over the scalp by means of the handle I2I.

It is to be noted that a very important function of the device is the elevating and lifting of the scalp by sliding the skin over the skull curvatures. When this function is performed, the scalp may be kept in elevated or lifted position without further manipulation for any desired duration of time. Such elevation increases the stretching action and considerably enhances the circulation to the elevated areas.

Another very important function is the production of flushing of the scalp by deliberately producing slipping or rubbing of the massage elements over the scalp, thereby squeezing and foreing blood in the direction of movement toward the respective areas.

Still another function is to produce a brushing of the scalp, thereby pulling on the hairs and their roots and resulting in the stimulation of circulation, nourishment and hair growth.

It is important to note that, except when the pads are intentionally permitted to slip or slide over the scalp, as when it is desired to produce a flushing or brushing action, the manipulation must be with suflicient gripping pressure so that the skin, instead of being merely moved from one place to another, is stretched firmly between two areas. The stretch must be adequate to overcome the cohesion or internal resistance of the elastic fibrous and muscular tissue. The manipulation must be vigorous but at the same time not so forceful as to injure the skin or its delicate appendages.

Because of the manner in which the two massage units are detachably secured to the yoke, they may be readily removed as previously described and used separately and independently for producing any one or more of the above described manipulations.

It should be understood that the drawing and specification illustrate merely preferred embodiments of the invention and that they are subject to considerable variation and modification without a departure from the spirit and scope of the claims which follow. Hence, the disclosure is to be considered as illustrative and exemplary of 10 the invention, and not in any wise as restrictive thereof.

I claim:

1. As an element of a scalp manipulating device, a yoke having an intermediate portion and two legs, said legs being substantially at right angles to said intermediate portion, two blocks, each secured to said intermediate portion a short distance inwardly of said legs, and a screwthreaded stud extending through each leg near its juncture with said intermediate portion and contacting one of said blocks, said blocks and studs constituting means to adjust the angle between the intermediate portion and said legs and thereby adjusting the pressure of the device against the skull to which it is applied.

2. A scalp manipulating device comprising a yoke having an intermediate portion and legs, means to retain said legs in adjusted position towards and away from each other, an arcuate member secured intermediate its ends to each of the free ends of said legs, massage pads mounted. on each of said arcuate members, and means for adjusting the position of said massage pads on said arcuate members, said last-named means including an elongated slot in each of said arouate members, a threaded stem carried by each of said massage pads and extending through each of said slots and a nut received on each of said stems.

ALBERT A. LA VERNE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 543,455 Weber July 23, 1895 723,735 Schillberg Mar. 24, 1903 1,322,924 Mezera Nov. 25, 1919 1,577,751 Paschall Mar. 13, 1926 1,712,764 Hassler May 14, 1929 1,726,560 Hassler Sept. 3, 1929 2,001,871 Foster May 21, 1935 2,249,145 Kraft July 15, 1941 2,504,791 Baron Apr. 18, 1950 FOREIGN PATENTS Number Country Date 265,342 Switzerland Nov. 30, 1949 327,336 France Mar. 24, 1903