US2671284A

US2671284A - Steaming attachment for flatirons

Info

Publication number: US2671284A
Application number: US53963A
Authority: US
Inventors: Clemons Clement Wood; Thomas S Zastrow
Original assignee: General Mills Inc
Current assignee: General Mills Inc
Priority date: 1948-10-11
Filing date: 1948-10-11
Publication date: 1954-03-09
Anticipated expiration: 1971-03-09

Description

March 1954 c. w. CLEMONS ETAL 2,671,284

STEAMING ATTACHMENT FOR FLATIRONS Filed Oct. 11, 1948 2 Sheets-Sheet l N VE N TORS 62 CLEMENT.WOOD CLEMONS THOMAS s. ZASTROW BY yh'l; C.

A T TORNE Y March 5 c. w. CLEMONS ET AL ,6 8

STEAMING ATTACHMENT FOR FLATIRONS Filed Oct. 11, 1948 2 Sheets-Sheet 2 IN VE N TORS CLEMENT wooo CLEMONS THOMAS s. ZASTROW B; Qua; 0.36M

A T TORNE Y Patented Mar. 9, 1954 STEAMING ATTACHMENT FOR FLATIRON S Clement Wood Clemons, Minneapolis,

and

Thomas S. Zastrow, St. Paul, Minn., assignors to General Mills, Inc., a corporation of Delaware Application October 11, 1948, Serial No. 53,963

Claims. 1

This application relates to steaming devices and more particularly to steaming devices for attachment to an ordinary flatiron.

Various devices have been proposed for use in combination with a regular flatiron to generate steam or to superheat steam from an external source and. permit the use of the fiatiron as a steam iron. Because the attachment and flatiron are separable, it is sometimes difficult to maintain the parts in good heat conductive relationship with each other. We have found that the problems of proper heat conduction are aggravated, in many cases, by differences in the warpage characteristics of the fiatiron and the attachment when heated. Such warpage also complicates the problem of attachment of the device to the iron, either because the usual rigid clamping means increases the warpage tendency or because the changeof shape due to warpage tends to loosen the clamping means.

With these problems and defects of the prior constructions in view, it is accordingly one object of the present invention to provide an improved steaming device for attachmentto the bottom of .an ordinary flatiron.

Another object is the provision of a steaming device for attachment to a fiatiron, which will accommodate predetermined relative warpage of the iron and device when heated without loss of the desired heat conducting characteristics.

A further object is the provision of means to accommodate such relative warpage, in combination with improved fastening means for maintaining the attachment and flatiron in close heatconductive contact at all times, regardless of the degree of such warpage.

ther objects and advantages .of the invention will be apparent from the following specification in which certain preferred embodiments of the invention have been described by way .of example. in general, these objects are accomplished by providing at least one of the contactingsuriaces of the iron and the attachment with a portion shaped to accommodate the anticipated relative warpage of the parts. Thus, for example, where certain portions of the bottom of the iron tend to warp downwardly when heated, it is possible to recess the cooperating upper surface portion of the attachment sufficiently to accommodate the expected warpage and maintain the major areas of the iron bottom and attachment surface in sufiicient proximity for good "heat conduction. lhus proper steaming and ironing temperature can be maintained in the attachment. Preferably, We use in combination with such recessed portions, improved fastening means which are capable of maintaining good pressure contact between the iron and attachment at all times through the action of interengaging cam surfaces, at least one of which is resiliently movable to accommodate varying degrees of Warpa e.

In the drawings which form a part of this specification,

Figure 1 is a side elevation of a steaming device attached to a flatiron.

Fig. 2 is a perspective view of the steaming attachment of Fig. 1 removed from the iiatiron.

Fig. 3 is a partial sectional view of a stream soleplate and the bottom of a fiatiron, showing in exaggerated form the effect of, w-arpage when the attachment does not include features of the present invention.

Fig. 4. is a view similar to Fig. 3 in which the steam s'oleplate is designed according to the present invention to accommodate the expected warp.-

age.

Fig. 5 is a partial view similar to Figs. 3 and 4 showing certain details of the embodiment of Fig. 2.

Fig. 6 is a partial sectional view showing details of the fastening means for use with the present invention.

Fig. 7 is a partial top plan of the rear "portion of Fig. 6.

Fig. .8 is a partial sectional view on the line 8-4? of Fig. 7, and

Fig. 9 is a view similar to Fig. 6 showing how the fastening means accommodates upward-warpage of the ends of the fiatiron.

In Fig. 1, the steaming attachment Ii] is shown in position below flatiron l2. The fiatiron includes the usual bottom plate l4. cover shell i6;

and handle l8. A control knob 20 maybe connected to a switch for controlling an electrical heating element within the fiatiron in known manner. Electric supply cord 22 provides current for the customary heating element.

The steaming attachment itself, as-shown in Fig. 2, includes a steam soleplate 24. A steam generator or chamber 26 is located within the soleplate 24 and is provided with steam outlets 21 through which the steam passes to the bottom of the soleplate 24 and thus into the material which is being ironed. Liquid is supplied to the steam chamber 26 by a suitable conduit "28 connected to a tank 38 or other suitable supply source. In this case the tank 30 is mounted pn brackets 12 at the rear end of the steam .sole- 3 be fed to the attachment, in which case the latter would superheat the steam or maintain it in vaporized condition.

When the steam soleplate 24 is clamped against the heated bottom plate 54 of fiatiron E2, the heat from the bottom surface 32 of the fiatiron will be conducted to the top surface 34 of the steam soleplate and will thus be available both for generation or heating of steam within chamber 26 and for heating the steam soleplate 24 and, in turn, the material being ironed.

In Fig. 3 we have shown in exaggerated form what happens when the bottom plate l4 of the fiatiron becomes warped during operation with a steam attachment which does not embody features of the present invention. In this figure, a combination has been illustrated in which the bottom surface 32 of the fiatiron plate 14 warps in an upward or concave direction as indicated.

As a result of this warpage, the bottom surface 32 of the fiatiron will tend to be spaced a considerable distance away from the top surface 34 of the steam soleplate 24, if there is no corresponding warpage of the latter member. Thus even though the bottom of the fiatiron and the top of the steam soleplate are in contact at the front portion 36 and the rear portion 38, there will be a substantial space (indicated at 40) between the major intermediate areas of the two members. It

is more difiicult, of course, for heat to be conducted across this air space 48 from the bottom 32 of the fiatiron to the top 35 of the steam soleplate. Therefore insufficient heat may be transferred for complete conversion of the liquid to steam and for maintenance of the necessary ironing temperatures at the bottom of the steam soleplate 24.

We have found that the warpage characteristics of a particular type of fiatiron are reasonably constant. In other words, a particular fiatiron model will have a bottom plate made of a given material, will have heating elements of a particular type arranged in a given location, and will have a particular method of holding the heati element in position. The arrangement and construction of these parts in a particular fiatiron model may give rise to warpage of the type illustrated in Fig. 3, while a different arrangement and construction of the parts in another type of iron may give rise to different warpage characteristics, for example, a downward or convex warpage of the intermediate bottom portions of the fiatiron plate. We believe, however, that the warpage characteristics of all irons of a given model or type of construction tend to be substantially similar as pointed out above. Thus we have found it possible to design a particular steam attachment for use with a fiatiron having such predetermined characteristics.

Since the amount of warpage in any given case is relatively small, and is usually limited, for example, to spacings of the order of five to fifteen thousandths of an inch, it has not previously been considered necessary to provide for the accommodation or compensation of such warpage. By ascertaining that even the small changes in spacing between the fiatiron and attachment, which are caused by such warpage of one or more of the parts, are critical in connection with the generation of steam and the maintenance of satisfactory ironing temperatures, we have made it possible to design steam attachments which operate satisfactorily on a commercial basis even with flatirons which exhibit a considerable tendency to warp when heated.

For example, as shown in Fig. 4, the upper surface 34 of the steam attachment may be shaped to correspond to the expected warpage of the fiatiron. In this case, in which the fiatiron warpage is similar to that of Fig. 3, the forward portion of the upper surface of steam soleplate 24 is tapered or sloped downwardly from point 42 throughout the forward area 44 to the tip of the soleplate. The rear portion 48 of the upper surface is likewise tapered or recessed downwardly from point 46 to the rear end of the soleplate. Such an arrangement permits the front and rear of the fiatiron bottom plate [4 to be deformed downwardly into the tapered or recessed portions 44 and 43 when the fiatiron is heated. The

surfaces

32 and 34 will accordingly be in contact at

points

42 and 46 rather than at the extreme ends as indicated at 36 and 38 in Fig. 3. The location of these contact areas nearer the central portion of the attachment makes it possible for the attachment to accommodate the same amount of warpage of fiatiron plate 14 as is shown in Fig. 3 with the presence of only a relatively small separating space 40 between the

surfaces

32 and 34 throughout their intermediate portions. Thus the surfaces will be in closer contact throughout the major heat transmitting area of the fiatiron bottom so that the necessary amount of heat can be transmitted to the steam soleplate 24 and steam chamber 26. In this connection it should be noted that the major area of the steam generating chamber 26 is located in the central portion of the soleplate. It is in and around this area that the heat transmission is improved by the structure of the present invention.

It is not necessary that the forward and

rear portions

44 and 48 of the upper surface 34 of the steam soleplate be tapered to correspond exactly to the expected warpage of the fiatiron bottom I4. It is suflicient, for example, if these portions be offset downwardly as indicated at 50 in Figs. 2 and 5 so that the forward portion 52 is horizontal but is displaced slightly below the intermediate major portion of surface 34.

Similarly, the rear portion of the steam soleplate 56 may be offset downwardly at 54 to accommodate downward warpage of the rear end of the fiatiron. It should be noted that the devices of Figs. 2 and 4 are not only designed to accommodate downward warpage of the front and rear of the fiatiron or, in other words, fiatirons which tend to be upwardly concave when heated, but also that these embodiments of the invention will operate satisfactorily with flatirons which have no warpage at all when heated. Thus the intermediate portion of the upper surface 34 is perfectly flat from ledge 50 to ledge Ed in Fig. 2 or between the

points

42 and 46 of Fig. 4 at which points the front and rear portions begin to taper downwardly. Thus the important major central area of the steam soleplate is perfectly flat in this case and is therefore capable of receiving heat efiiciently from the major central portion of a fiatiron bottom having no warpage as well as from a fiatiron bottom having upward or concave warpage. As indicated below, this particular design will also operate efficiently with flatirons having a downward or convex warpage of the bottom, since the particular fastening means of the steam soleplate 24 are designed to permit limited upward movement of the ends of the fiatiron with respect to the soleplate.

The exact location of the lines of offset 50 and 54 orthe lines of taper 42and 46 may, of course,

actress be varied to accommodate the range or warpage characteristics of any particular fiatiron model with which the attachment is designed for use.

In the embodiment of Figs. 2 and 5, there will of course be some space indicated at 58 in Fig. 5 between the bottom of the flatir'o'n and the forward portion 52 of the steam soleplate nearest the ledge. This space is not critical, however, since the area of portion 52 is relatively small and does not interfere with heat transfer to any substantial area of the steam generating chamber 26 or the main ironing portions of the soleplate.

With reference to Figs. 2, 6, '7, and 8, the improved means for attachment of the steam soleplate 24 to the fiatiron i2 will now be described. In this particular case, the steaming device is designed for use with a fiatiron in which the edges of the flatiron bottom plate M are beveled or sloped outwardly and downwardly. Such beveled bottom plates are customarily used in fiatirons to facilitate ironing around buttons and also to improve the appearance of the iron. The sloping or beveled forward edge 60 of the flatiron bottom plate M is received beneath an upwardly and rearwardly inclined clamping portion or toe box 52, the inner surface 64 of which is sloped to correspond to the inclined forward edge 66 of the ilatiron. Thus, as long as the flatiron bottom It is urged to the left in Fig. 6 against the inclined retaining surface 64, the forward portion of the flatiron will be held in close engagement with the forward end of the steam soleplate. In other words, the use of the inclined cooperating surfaces 6 and 6 1 gives rise to a camming engagement between the forward portions of the flatiron and steam soleplate such that relative movement of the flatiron it to the left or against the inclined retaining portion 64 tends to urge the attachment even more tightly up against the bottom of the flatiron.

As shown in Fig. 2, a movable retaining or clamping member 55 is provided at the rear of the steam soleplate 24. This movable clamp is in the form of a heavy wire which is bent to provide clamping arms 68 for engagement with the rear beveled portions of the flatiron bottom plate I i. Other portions of the clamping member 65 extend through and are pivoted to the supporting brackets '52 of tank 30 at points 1-0. An operating handle Hi is fastened to one of the shaft portions 70 for manual operation of the latch 86. A strong spring 16 is designed to urge the latching portions 68 resiliently downward toward the steam soleplate 24, i. e., against the sloping or beveled rear edge portions 18 of the bottom plate i l of the flatiron.

As is shown in Figs. 7 and 8, this rear portion 18 slopes both downwardly toward the rear and downwardly toward the lateral sides of the fiatiron plate i4. Thus, the resilient engagement of the latching portions 68 which are forced downwardly against portions 18 by the spring 16 tends to exert a further camming action on the bottom plate i4 and to force the rear portion of the plate downwardly in firm contact with the rear of the steam attachment, as well as forwardly toward the front of the iron. Thus the beveled forward edge 60 is held against the inclined retaining surface ea of the toe portion 62. As pointed out above, this tendency of the latch 68 to urge the bottom plate 14 toward the forward end of the attachment makes the camming engagement of surfaces '60 and 64 effective "to clamp the forward portions of the steam 1 soleplate and neuron tbthi. specific latching and retaining means is claimed per se in a copending application of John N. Polivka et a1., Serial No. 53,902, filed October 11, 1948, and assigned to the same assignee as the present invention. I g

The present invention includes the combination of such resilient latch means with the particular location of recessed "portions in the steam soleplate upper surface. Thus the combination of cooperating cam surfaces at the front and rear of the attachment not only "maintains the attachment and liatiron in proper contact with each other, but also permits limited relative warpage of one member with reference to the other, as shown in dotted lines in Fig. 6. Thus, if the li'atiron warps as previously described in connection with Figsg3 and 4, the front and rear portions of the fiatiron plate [4 will be deformed downwardly into the recessed or offset portions 52 and 5 6. As this deformation takes place, however, the latch member 68 will be urged downwardly under the influence of its spring and will not only maintain the rear portions :of the flatiron and steaming attachment in proper contract with each other but will alsourge thefiatiron forwardly with respect to the steam soleplate so that the camming engagement of surfaces 50 and 53 will effectively maintain the forward portions of the flatiron and attachment in close contact. In the absence of the camming engagement of the respective retaining means, the downward warpage of the front and rear of the en into the recessed portions s2 and 55 would loosen the clamping engagement of the respective parts and wouldaccording-lypermit some relative separation of the attachment and flatiron which would be detrimental to proper heat conduction between the parts. This difliculty is avoided by the use of attaching means at the respective ends of the steam rsoleplate :24 which not only have a clamping action tending to hold the parts together but also have a camm'ing engagement tending to take up any slack in the clamping surfaces which may result from warpage of the parts.

Fig. 9 shows how the clamping means permits warpage of the flat-iron in the opposite directionfrom that shown in Fig. 6. In this case theendsof the fiatiron plate i-i warp upwardly when hot, as shown by dotted lines. As the front of the plate M warps up, the camming engagement of surfaces Bt and 64 tends to move the plate it 'back toward the rear of the steam soleplate e25. Resilient latch 58 is designed :to'accommodate this rearward movement and topermit corresponding upward warpage of the rear of plate [4, by movement from the heavy line position to the dotted line position of Fig. 10. In other words, there is both relative longitudinal and vertical movement between latch 58 and beveled edge 1-8. At the same time, resilient latches-continues to urge the plate Hi downwardly and forwardly so that the combination of the -latch and the inclined retaining surface (it holds the :flatiron plate M and steam soleplate 2 t close heat-conductive contact throughout their major central or intermediate areas. Thus adequate heat conduction can be obtained for the steam generating and ironing areasof the attachment according to this invention whether the .flatiron Warpage be concave or convex.

It will be apparent from the foregoing description that an improved steam attachment has been provided for use with an ordinary :flatiron that tween the parts in spite of relative differences in warpage of the attachment and fiatiron.

Obviously, variations in the specific details of construction of the parts and the manner in which they engage each other to perform their specific functions may be made in the light of the teachings of this application. This invention is therefore intended to include all such modifications, changes, and improvements as fall within the spirit and scope of the attached claims.

Now, therefore, we claim:

1. A steaming device for use with any one of a plurality of flatirons of different possible but individually unpredictable warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation, comprising a steam soleplate having a steam chamber therein, and means for attachment of the soleplate to the flatiron with its upper surface against the bottom of the flatiron, the upper surface of the soleplate having a recessed portion outside the main area of the steam chamber at one end, said recessed portion having an area and depth adapted for accommodation of relative downward warpage of the corresponding end of any of said plurality of flatirons said recessed portion minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the fiatiron and steam chamber area during such warpage.

2. A steaming device for use with any one of a plurality of flatirons of different possible but specifically unpredictable warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation, comprising a steam soleplate having a steam chamber therein, means for attachment of the soleplate to the fiatiron with the upper surface of the soleplate against the bottom of the iron, the upper surface of the soleplate being tapered downwardly at each end outside the major area of the steam chamber, the area and depth of said tapered ends corresponding substantially to the maximum expected relative downward warpage of the ends of any of said plurality of flatirons said tapered ends minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

3. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation, each of which irons has an outwardly and downwardly beveled lower edge, said device comprising a steam soleplate having a steam chamber therein, and means for attachment of the soleplate with its upper surface against the bottom of the iron, said attachment means comprising a resilient latch on the soleplate resiliently movable downwardly against the beveled lower edge of the iron, a portion of the upper surface of the soleplate outside the main areaof said steam chamber and adjacent said latch being recessed in an area and depth adapted to accommodate relative downward warpage of the corresponding-portion of any of said plurality of flatirons said recessed portion minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

4. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation, each of which irons has an outwardly and downwardly beveled lower edge, said device comprising a steam soleplate having a steam chamber therein, and means for attachment of the soleplate with its upper surface against the bottom of the iron, said attachment means comprising a retaining member at one end of the soleplate for engagement with the beveled lower edge of the corresponding end of the flatiron, a latch member at the opposite end of the soleplate having a portion movable downwardly along a line angularly intersecting the beveled lower edge of the flatiron, and resilient means urging the latch portion downwardly against the beveled edge, the upper surface of the steam soleplate having a recessed portion outside the main area of said steam chamber and adjacent at least one of said latch and retaining members, said recessed portion having an area and depth adapted for accommodation of the maximum relative downward warpage of the corresponding portion of any of said plurality of flatirons said recessed portion minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

5. A steaming device for use with any one of a plurality of flatirons having different possible but not necessarily predictable warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation, comprising a steam soleplate having a steam chamber therein, and means for attachment of the soleplate with its upper surface against the bottom of the flatiron, said attachment means comprising a fixed inclined retaining member at one end of the soleplate having cam engagement with one end of the fiatiron for urging the flatiron and soleplate against each other in response to relative longitudinal movement of the iron and soleplate in one direction, and a manually movable resilient latch at the other end of the steam soleplate for cam engagement with the opposite end of the flatiron along a path urging the flatiron and soleplate against each other and tending to cause said relative longitudinal movement in one direction, the upper surface of the steam soleplate having recessed portions outside the main area of the steam chamber and adjacent both the retaining member and latch, said recessed portion having an area and depth sufficient for accommodation of relative downward warpage of the respective ends of any of said plurality of flatirons said recessed portion minimizing the spacing between the flatiron and the steam chamber of the steam soleplate during said relative downward warpage and thereby minimizing the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

6. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics, at least one such fiatiron being characterized by variations in relative downward warpage of its edges when heated and cooled during normal operation, said device comprising a steam soleplate having a steam chamber therein, and means on the soleplate at opposite edges of the steam chamber for attachment of the soleplate to the bottom of a flatiron, said attachment means comprising a resilient member constantly urging the flatiron and steam soleplate toward each other at said opposite edges throughout such warpage variations, and the upper surface of the steam soleplate having a recessed portion at one of said opposite edges, said recessed portion having an area and depth adapted for accommodation of the relative downward warpage of the corresponding edge portion of any of said plurality of flatirons said recessed portion minimizing the spacing between the fiatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

7. A steaming device for use with any on of a plurality of flatirons of different possible warpage characteristics, at least one such flatiron being characterized by variations in relative downward warpage of its edges when heated and cooled during normal operation, said device comprising a steam soleplate having a steam chamber therein, and means on the soleplate for attachment of the soleplate to the bottom of a fiatiron, said attachment means constantly urging the flatiron and steam soleplate toward each other in the area of said steam chamber throughout such warpage variations, and the upper surface of the steam soleplate having a recessed portion outside the area of the steam chamber, said recessed portion corresponding in area to one edge portion of the flatiron and having a depth corresponding substantially to the maximum expected relative downward warpage of the corresponding edge portion of any of said plurality of fiatirons said recessed portion minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative downward warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

8. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation comprising a steam soleplate having a steam chamber extending over a predetermined area therein, and means for attachment of the soleplate with its upper surface against the bottom of a fiatiron, a substantial portion of the upper surface of the soleplate located within the area of possible engagement of the flatiron but outside the major area of the steam chamber and a substantial portion of the upper surface about the major area of the steam chamber being at different levels to accommodate relative warp- 10 age of the corresponding portions of any of said plurality of fiatirons, and portions of different levels minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

9. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation comprising a steam soleplate having a steam chamber extending over a predetermined area therein, and means for attachment of the soleplate with its upper surface against the bottom of a flatiron, substantial portions of the upper surface located at the front and rear of the device within the area of possible engagement of the flatiron but outside the major area of the steam chamber lying at a different level from the plane of the intermediate portion of the upper surface of the soleplate, said portions of difierent levels minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

10. A steaming device for use with any one of a plurality of flatirons of different possible warpage characteristics which may vary in any given iron when such iron is heated and cooled during normal operation comprising a steam soleplate having a steam chamber extending over a predetermined area therein, and means for attachment of the soleplate with its upper surface against the bottom of a fiatiron, substantial portions of the upper surface located at the front and rear of the device within the area of possible engagement of the fiatiron but outside the major area of the steam chamber lying below the plane of the intermediate portion of the upper surface said lower front and rear portion minimizing the spacing between the flatiron and the steam chamber area of the steam soleplate during said relative warpage and thereby maintaining the necessary heat conducting relation between the flatiron and steam chamber area during such warpage.

CLEMENT WOOD CLEMONS. THOMAS S. ZASTROW.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 990,922 Stoll May 2, 1911 1,023,802 Blattle Apr. 23, 1912 1,858,250 Smith May 17, 1932 2,302,264 Schwartz Nov. 17, 1942 FOREIGN PATENTS Number Country Date 487,322 Germany Dec. 6, 1929