US2512220A

US2512220A - Electric iron

Info

Publication number: US2512220A
Application number: US752579A
Authority: US
Inventors: Irving E Aske
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-06-05
Filing date: 1947-06-05
Publication date: 1950-06-20
Anticipated expiration: 1967-06-20

Description

2 Sheets-Sheet l l. E. ASKE ELECTRIC IRON June 20, 1950 Filed June 5, 1947 June 20, 1950 l. E. AsKE 2,512,220

ELECTRIC IRON Filed June 5, 1947 2 Sheets-Sheet 2 4 4 4 7, -mmn INVENTOR.

@Y @im mi ATTORNEY Patented June 20, 1950 UNITED STATES PATENT OFFICE ELECTRIC IRON Irving E. Aske, Ludington, Mich.

Application June 5, 1947, Serial No. 752,579

11 Claims. 1

This invention relates to improvements in electric irons.

The main objects of this invention are:

First, to provide an electric iron in which the sole plate is formed as a casting or forging having two cavities or recesses therein into which the heating element holders of sheet metal are inserted and expanded into interlocking retaining and heat transfer engagement with the sides of the cavities to effectively retain the heat element and provide sufficient heat exchange.

Second, to provide an electric iron in which the heating units are effectively clamped in their holders to provide efficient heat exchange and prevent overheating or burning out of the heating elements or unit.

Third, to provide an electric iron in which the heating elements are effectively retained, at the same time permitting replacement or removal thereof for repair by the dealer as distinguishedr from requiring return to the factory.

Fourth, to provide an electric iron having these advantages which may be very economically manufactured both as to parts and the assembly thereof.

Fifth, to provide an electric iron which eliminates the use of screws or similar fasteners for clamping the heating elements in the sole plate and one in which the heating element holders constitute reinforcing means for the sole plate.

Sixth, to provide a method of producing electric irons having the several advantagesv which may be very economically and efficiently practiced with simple equipment.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims.

Preferred embodiments of the vinvention arev illustrated in the accompanying drawing, in which:

Fig. l is a fragmentary plan view of the sole plate parts of an electric iron embodying the invention with the heating elements mounted therein, the superstructure and thermostat being omitted. v

Fig. 2 is an enlarged fragmentary transverse section on line 2-2 of Fig. 1.

Fig. 3 is a transverse section of one of the heating element holders with the heating element and top plate therefor assembled therein, the heating element parts being shown conventionally.

Fig. 4 is a fragmentary sectional view corresponding to that of Fig. 2 with the heating element holder and the .parts assembled ,therein as shown in Fig. 3 inserted in a recess provided therefor in the sole plate body member.

Fig. 5 is a fragmentary sectional view illustrating further steps in the method and further structural details of the iron.

Fig. 6 is a fragmentary sectional view illustrating further steps of the method.

Fig. '7 is an enlarged fragmentary sectional view illustrating the final step of the method and also structural details.

Fig. 8 is a fragmentary sectional view corresponding to that of Fig. 5 illustrating another method of manufacture or certain steps in a modified method of manufacture.

Fig. 9 is an enlarged fragmentary sectional view illustrating a succeeding step in the method of assembling, embodying the step illustrated in Fig. 8.

Fig. 10 is a fragmentary section corresponding to that of Fig. 2 illustrating a succeeding step in the rmethod of assembly embodying the steps shown in Figs. 8 and 9.

Fig. 11 is a fragmentary section illustrating a somewhat modified form or embodiment of the invention and one of the steps in producing the same.

Fig. 12 is a fragmentary section corresponding to that of Fig. 11 illustrating a succeeding step in the manufacture.

In the embodiment of the invention and the steps in the method of manufacture illustrated in Figs. 1 to 8 inclusive, l is a sole plate or body member formed of a casting or forging and having two longitudinally extending recesses or cavi- .

vties

2, 2 separated throughout the length thereof by a central longitudinal rib 3 of substantial width and mass. The recesses are of substantial depth, desirably at least of an inch in an iron the totalthickness of which is of an inch. The thickness of the iron beneath the holder is desirably of the order of e of an inch. I am referring to this at this time for the reason that I have made no attempt in the accompanying drawings to show the parts in accurate proportions.

In the embodiment shown in Figs, 1 to 7 inclusive, the side walls 4 of the recesses are inclined inwardly and the inclination may be of the order vof 5 to 10. This, however, may be very greatly varied.

The longitudinal rib 3 is of such width as to serve as a support for the thermostat and ordinarily as means for attachment of the superstructure and handle. The thermostat, however, is not illustrated as suitable thermostats are known in the art.

The casing is ordinarily a sheet metal stamping and has the handle mounted thereon. The heating element holders are sheet metal stampings and of channel-shaped cross section.

When the sole plate body member is formed of iron the heating element holders are desirably of sheet steel and where the body members are formed of aluminum or metal other than iron the holders should desirably be formed of aluminum or other material having an expansion coefficient approximating that of the metal of the body member.

The holders 5 may be initially formed with A straight sides E and are of a shape corresponding to the general outline of the recesses 2 as is shown in Fig. 1. The iron illustrated has a square heel portion but irons are frequently tapered at both ends in which oase the holders are correspondingly shaped.

The heating elements are conventionally illustrated and comprise the micaJ rack or card I having the resistance wire or tape 8 thereon, insulating plates S and I Il being disposed below and above the resistance unit.

The top plate II is arranged on the heating element, this being desirably a metal plate of about 1/8 inch thickness and of such shape and dimensions that its edges fit within the walls of the holder as is shown in Fig. 3.

With the holder heating unit and top plate assembled in the holder, the holder is inserted in the recess 2 as shown in Fig. 4. It is apparent that as an alternative the holder may be first inserted and secured in the recess and the heating element parts and top plate then placed therein. However, ordinarily it is a manufacturing convenience to assemble these parts in the holder before introducing into the press for securing operations. After the holders are inserted in the recesses, the walls of the holders are expanded or forced as shown in Figs. 2, 5, 6 and 7 into thrust or pressure retaining heat transfer engagement with the walls 4 of the recess and with the bottoms of the holders in supported heat transfer engagement with the bottoms i Z of the recesses. It will be noted that the recesses 2 in the sole plate I are upwardly facing and that the open sides of the channel shaped holders 5 are also upwardly facing. Facing the sole plate recesses and also the open sides of the channel shaped holders upwardly facilitates assembling all the parts into a very secure and close heat contacting engagement, and also facilitates by the same operations simultaneously securing the channel shaped holders 5 within the recess 2 of the sole plate, and the heating elements and top plates within said holders, as will be apparent from the construction shown and heretofore described.,

The bottom and sides of the recesses of the castings or forgings may be finished as by using a carboloy burring tool. I consider that it is of substantial manufacturing convenience to form the side walls of castings or forgings with approximately straight walls or even some draw and the-n machine `them to provide the undercuts er inwardly inclined surfaces.

After the holders are expanded or forced into pressure retaining heat transfer engagement with the walls of the recess, the projecting edges I3 which constitute clamping iianges are folded inwardly upon the top -plate Il into clamping and heat transfer engagement therewith as best shown in Figs. 2 and '7. These clamping anges or portions of the holders are of substantial width and in the embodiment illustrated overlap substantial portions of the top plates on three sides thereof or two sides and the end thereof with the exception of the portion I4 which is left in upright position to provide a space for the nut I5 of the binding post I6. At the other end, the portion l1 of the ila-nge is left upstanding to provide space for the nut I5 of the other binding post I5. n

In Figs. 5, 6 and 7, I illustrate a practical method of expanding the sides of the holders into retaining engagement with the walls of the recess and the turning of the retaining flange portion into clamping position. The supporting bed for the sole plate is not illustrated. The die member I8 is provided with recesses i9 of suitable dimensions to receive the edges i3, the die member I3 being disposed within supporting member 20 for exteriorly supporting the flange portions I3 of the holders while they are subject to edge thrust by the member i8. This edge thrust expands or distorts the holders from the position shown in Fig. 2 so that its sides are brought into contacting retaining engagement with the undercut walls of the recesses as is shown n Fig. 5.

The next step illustrated in Fig. 6 is to turn the flange portions I3 inwardly by means of the die member 2| which has inclined edges 22 engaging the flange portions while they are in the upright position shown in Fig. 5 and turning them inwardly as the die member travels downwardly, and finally the clamp portions I3 are clamped firmly upon the top plate II by a die member 23.

I have illustrated these as separate or succes'sive steps with three die members but it will be understood that the operations may be performed by other apparatus than I have illustrated.

As the holders are expanded. into engagement with the walls of the recesses the bottom of the holder is firmly pressed against the bottoms of the recesses thereby insuring a good heat transfer contact between the holders and the bottoms of the recesses as well as between the sides of the holder and the side walls. The top plate is by this arrangement of parts provided with an elective heat transfer connection to the sole plate and this results not only in a quick transfer of heat but in protection of the heating eleN ments or units. If, however, the heating elements are found to be defective or become defective in use, the. flanges I3 may be turned up with a suitable tool to permit removal and replacement of the heating elements.

While the gauge of the holders may be varied considerably, when formed of sheet steel I consider .025 of an inch a desirable gauge. When formed of aluminum or brass I consider .O40 of an inch satisfactory not only for heat transmission but providing the desired pressure engagement with the top plate and engagement with the walls of the recess.

With the parts thus arranged, the holders serve as effective reinforcing elements for the sole plate and permit the use of sole plates having thin walls between the heating elements and the faces of the sole plates. This results in a rapid transfer of heat to the face of the sole plate with little mass to cause override in the temperature on initial heating. The holders are effective in preventing warpage of the iron at operating temperatures and at the variations in temperatures to which irons are subjected, particularly when used for relatively short periods.

In the embodiment of the invention illustrated in Figs. 1 to '7 inclusive the holders 5 are initially formed with straight sides and flat bottoms, the Sides being distorted or upset into pressure or thrust retaining heat transfer engagement with the walls of the recess.

In the embodiment and method illustrated in Figs. 8, 9 and 10 the bottom 60 0f the holder 5 is upwardly curved transversely of the holder, as shown in Fig. 8. In this embodiment, the holder with the heating element assembly and the top plate ll superimposed thereon are introduced into the recess and the assembled parts subjected to a press such for example as shown in Fig. 5, the die member i3 imparting such pressure to the top plate Il as will flatten the upwardly curved bottom Ell against the bottom I2 of the recess and into heat transfer contact therewith. This straightening or fattening of the bottom forces the bottom corners of the holder` outwardly into the undercut of the recess. During this operation the side walls of the holder shift from the position shown by full lines in Fig. 8 and dotted lines in Fig. 9 to approximately the position shown by full lines in Fig. 9. The succeeding operation as illustrated in Fig. ll) is substantially that shown in Fig. 6.

After the edges of the holder are turned inwardly, as shown in Fig. 10, they are clamped down upon the top plate as shown in Fig. 7. This initial forming of the holder with the curved bottom enables the interlocking of the pressure engagement of the holder with the walls of the recess with somewhat less stress on the walls of the holder-that is, as compared to the method shown in Figs. l to 7 inclusive.

In the embodiment of the invention illustrated in Figs. 11 and 12 the bottom 25 and the sides 26 of the recess are left rough or unfinished as they ordinarily come from the mold. The holder 5 is the same as that shown in Figs. 3 and 4 for example, that is, the bottom is fiat and the side walls are vertical thereto. The holder, however, is of such dimensions that a forced or pressure ft is required to seat in the recess. The same press and die parts may be utilized as illustrated in the other figures described but the holder is forced into the recess into engagement with such pressure or thrust that it has a pressure of thrust retaining engagement with the side walls of the holder, the minute projections commonly found on surfaces of unfinished castings being embedded into the surface of the holder both as to the sides and bottom thereof. This results in an effective interlocking retaining engagement even when there is the slight draw or outward inclination to the side walls necessary orconsidered desirable for the molding operations. The method of assembly employing the inwardly inclined side walls or undercut with smooth surfaces on the walls is, however, preferred by me, as the most effective heat transfer retaining or interlocking engagement is secured by that means. rEhe eliminating of the undercut or finishing steps decrease `somewhat the cost of manufacture.

I have illustrated and described an electric iron embodying the preferred forms ofthe invention. I have not attempted to illustrate or describe other embodiments orv adaptations which I contemplate as it is believed that this disclosure will enable those skilled in the art to embody or adapt the invention as may be desired. Further, I have described my method and illustrated steps and a satisfactory means for practicing the same. I desire to point out, however, that other apparatus than that illustrated might be employed for practicing the method.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. An electric iron comprising a sole plate member having laterally spaced upwardly facing recesses of substantial depth disposed longitudinally thereof, the walls of the recesses being inwardly inclined, the sole plate member having an integral longitudinal rib of substantial width and mass between and separating the recesses throughout the length thereof, sheet metal heating element holders of upwardly facing channel section and of shapes corresponding to the outlines of the recesses disposed Within the recesses and having their side walls in expanded retaining and heat transfer contacting engagement with corresponding inwardly inclined walls of the recesses and their bottoms in pressed heat transfer relation to the bottoms of the recesses with portions of the sides of the holders extending from the recesses and constituting heating element clamping flanges, heating elements disposed in said holders, and top plates for said heating elements disposed thereon, the flanges of the holders being bent inwardly into pressing and clamping retaining and heat transfer engagement with the edges and border tcp portions of the top plates.

2. An electric iron comprising a body member having an upwardly facing recess therein of substantial depth and having undercut walls, a sheet metal heating element holder of upwardly facing channel section corresponding in shape to the outline of the recess disposed within the recess with edge portions thereof projecting from the recess to constitute heating element clamping flanges, the sides of the holder being in expanding pressure retaining engagement with the undercut walls of the recess, the bottom of the holder being in heat transfer supported relation to the bottom of the recess, a heating element disposed in said holder, and a top plate for said heating element disposed thereon, the flanges of the holder being in heat transfer engagement with the edges of the top plate and in clamping heat transfer contact with substantial portions of the top of the top plate.

. 3. An electric iron comprising a sole plate member having laterally spaced upwardly facing recesses of substantial depth separated by an integral longitudinal rib of substantial width and mass, the sole plate at the bottoms of the recesses being relatively thin as compared to the horizontal thickness of the side walls of the recesses, the side walls of the recesses being undercut, heating element holders of upwardly facing channel section disposed within the recesses, the side walls of the holders being in interlocking engagement with the undercut side walls of the recesses, the holders constituting reinforcing elements acting to resist warpage of the sole plate, and heating elements disposed in said holders and clampingly retained thereby.

4. The method of making electric irons comprising the steps of providing a sole plate member having an upwardly facing recess of substantial epth and having a flat bottom and inwardly inclined side walls, inserting a channel-shaped heating element holder of sheet metal into said sole plate upwardly facing recess with the open side of the channel-shaped holder also facing upwardly and with a flat bottom supported on the flat bottom of the recess and vertical side walls projecting from the recess, the holder being of a shape corresponding to the outline of the recess and having a heating element disposed therein together with a top plate for the heating element closely fitting within the holder, and applying pressure to the edges of the walls of the holder while exteriorly supporting the portions thereof projecting from the recess to expand the holder 'walls within the recess into retaining heat transfer contact with the walls of the recess, and folding the projecting edges of the holder inwardly into clamping retaining heat transfer engagement with the edges and border top portions of the top plate.

5. The method of making electric irons comprising the steps of providing a sole plate member having an upwardly facing recess of substantial depth and havingV a flat bottom and inwardly inclined side walls, inserting a channel-shaped heating element holder of sheet metal into said sole plate upwardly facing recess with the open side of the channel-shaped holder also facing upwardly and with a flat bottom supported on the flat bottom of the recess and vertical side walls projecting from the recess, the holder being of a shape correspon-ding to the outline of the recess, and applying pressure to the walls of the holder to expand the holder walls within the recess into retaining heat transfer contact with the inwardly inclined walls of the recess.

6. rlhe method of making an electric iron comprising the steps of providing a sole plate member having an upwardly facing recess of substantial depth and having opposed inwardly inclined side walls. inserting 'a channel-shaped heating element holder of sheet metal into the recess with the open side of the channel shaped-holder also facing upwardly and with the edges of the holder side walls projecting from the recess, the holder being of a shape corresponding in outline to the outline of the recess and having a transversely and upwardly curved bottom and having a heating element disposed therein together with a top plate superimposed on the heating element and fitting within the wall of the holder, applying pressure to the top plate and to the edges of the wall of the holder while transversely supporting the saine to flatten and compress the curved bottom onto the bottom of the recess, the flattening of said bottom forcing the walls of the holder into retaining and heat transfer engagement with the walls of the recess, and folding the edges of the holder element onto the top plate and into retaining heat transfer engagement therewith- 7. An electric iron comprising a sole plate member having laterally spaced upwardly facing recesses of substantial depth extending longitudinally thereof, the sole plate member having an integral longitudinal rib of substantial width and mass between and separating the recesses throughout the length. thereof, bendable sheet metal heating element holders of upwardly facing channel section and of a shape corresponding to the outlines of the recesses disposed within the recesses and having their side walls in side by side contacting thrust retaining and heat transfer engagement with corresponding walls of the recesses and their bottoms in direct contactrig heat transfer relation on the bottoms of the recesses with portions of the sides of the holders extending above the walls of the recesses and constituting heating element clamping flanges, heating elements disposed in said lholders, and metal to-p plates of substantial thickness for said heating elements disposed thereon, the flanges of the holders being retainingly clamped and in heat transfer engagement with the edges and border top portions of the top plates.

8. An electric iron comprising a body member having an upwardly facing recess therein of substantial depth, a bendable sheet metal heating element holder of upwardly facing channel section corresponding in shape to the outline of the recess disposed within the recess with edge portions thereof constituting bendable heating element clamping flanges, the sides of the holder being in side by side direct contacting thrust engagement with corresponding walls of the recess, the bottom of the holder being in direct contasting heat transfer engagement with the bottom of the recess throughout the area thereof, a heating element disposed in said holder, and a metal top plate of substantial thickness for said heating element disposed thereon, the flanges of the holder being clamped upon the top plate in heat transfer engagement therewith,

9. An electr-ic iron comprising a body member having an upwardly facing recess therein of substantal depth and having undercut walls, a sh eet metal heating element holder of upwardly facing channel section of a shape corresponding to the outline of the recess disposed within the reless with its bottom in direct heat transfer contact with the bottom of the recess and with edge portions thereof projecting from the walis of the recess and constituting bendable heating element retaining flan es, the sides of the holder being in side by side contacting retaining and heat transfer engagement with the corresponding undercut side walls of the recess, said heating element being clamped between flanges the bottom of the holder with the in heat transfer association with the element.

19. An electric iron comprising a sole plate member having laterally spaced. upwardly facing recesses of substantial depth separated by an integral longitudinal rib of substantial width and mass, the thickness of the sole plate at the hottoms of the recesses being of the order of of an inch, bendable sheet metal holders of upwardly facing channel section and of outline corresponding to the shapes of the recesses disposed in the recesses with edge portions thereof projecting from the side walls of the recesses and constituting heat element retaining flanges, the sice walls of the holders ibeing in side by side contacting retaining and heat transfo engagement with the side walls of the recesses, the bottoms of the holders being in direct heat transfer contact with the bottoms of the recesses, the holders constituting reinforcing elements for the sole plate acting to resist warpage thereof, heating elements disposed in said holders and metal top plates for said heating elements disposed thereon and being of substantial thickness, the flanges of the holders being in heat transfer association with the top plates.

ll. An electric iron comprising `a sole plate member having an upwardly facing recess therein of substantial depth and embracing a substantial area of the sole plate, the sole plate at the bottom of the recess being relatively thin as compared to the horizontal thickness of the side Walls of the recess, a bendable sheet metal heating element holder of upwardly facing channel section disposed within the recess with the bottom of the holder in direct heat transfer and reinforcing contact/with the bott-om of the re- 9 ness throughout the area thereof, the side Walls of t1 e holder Ibeing in direct heat transfer and interengaging retaining engagement with the side Walls of the recess thereby retaining the holder in the recess to constitute a reinforcing eiernent for the sole plate resisting Warpage thereof, a heating eernent disposed in said. holder, and a metal top plate of substantial thickness superimposed on said heating element with its edges in engagement with the inner sides of the side Walls of the holder, the side Walls projecting above the top plate and being clampingly fo1ded upon the top thereof into retaining hea-t transfer engagement therewith.

IRVING E. ASKE.

10 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 876,639 Harwood Jan. 14, 1908 1,150,428 Hadaway Aug. 17, 1915 1,645,867 Louthan Oct. 1S, 1927 1,821,822 Wiegand Sept. 1, 1931 1,998,764 Jordan et a1 Apr. 23, 1935 2,049,089 Stackhouse July 28, 1936 FOREIGN PATENTS Number Country Date 503,299 Great Britain Mar. 30, 1939