US1995035A - Sadiron sole plate - Google Patents

Description

- March 19; 1935. M. w. McARDLE ETAL SADIRON SOLE FLA-TE Filed Feb. 9, 1933 4 Sheets-Sheet 1 March 19, 1935. M. w. McARDLE El AL SADIRON SOLE PLATE Filed Feb. 9. 1933 4 Sheets-sheaf 2 March 19, 1935.

M. W. M ARDLE Eli AL SADIRON soLfi PLATE Filed Feb. 9, 1953 4 Sheets-sheaf, s

March 19; 1935.

M. W. M ARDLE r AL SADIRON SOLE PLATE 4 ets-Sheet 4 I Filed Feb. 9, 19

a W/zM/ m a Patented Mar. 19, 1935 UNITED STATES SADIRON SOLE PLATE Michael W. Y McAi-dle and John W. Lynch,

Chicago, Ill., assignors to Chicago Flexible Shaft Company, Chica Illinois Application February 9,

15 Claims.

This invention relates to sadirons and has particular reference to a new and improved sole plate for electric sadirons.

A purpose of the invention is to provide a composite sole plate having an outer shell of sheet metal and a body or filler which may be of a different metal and which is shaped and secured to the shell ina manner to compensate for diff rences in thermal expansion between the parts I and to hold the ironing surface of the shell firm- 1y against the body.

We have also aimed to provide a sole plate for sadirons which is light in weight but which has an outer surface of such hardness as to resist mechanical damage such as scratching and marring under the usage to which such articles are normally put.

Another object of the invention is the provision of a composite sole plate having structural characteristics insuring satisfactory performance in service,

Another aim of the invention is the provision. of a sole plate having means for preventing the improper assembly thereof whereby to insure proper performance in service.

Another object of the invention is to provide a composite sole plate wherein the shell 'is of steel or other hard sheet material and the body is of a light weight material such as aluminum, and the parts are so shaped as to compensate for the efiects of the difference in thermal expansion of the parts upon the curvature of the ironing surface of the sole plate.

We have also aimed toprovide a composite sole plate having a shell and a body, the latter being so constructed that at no time during the normal operation of the iron will the body exert undue pressure outward against the side walls of the shell.

Other objects and attendan advantages will become apparent to those skilled in the .art from the following description and the accompanying drawings, in which- Figure 1 is a top view of the shell. showing in dotted lines the shape characteristics of the blank .from which the shell is drawn;

Fig. 2 is a section on the line 2-2 of Figure 1;

Fig. 3 is a longitudinal section through one of the bosses;

Fig. 4 is a top view of the shell with the body in place showing the shell after the preliminary bending thereof;

Fig. 5 is'a section on the line- 5-5 of Fig. 4

go, 111., a corporation of 1933, Serial No. 655,932 7 showing the preliminary ben of the shell;

Fig. 6 is a top view ofv the shell and body after the preliminary comer forming operations, showing in dotted lines the manner in which the dies form the corners;

Fig. 7 is a section through the point of the shell and body parallel to the ironing. surface showing the relationship of the parts in Fig. 4;

Fig. 8 is a section on the line 88 of "Fig. 7;

Fig. 9 is a section similar to Fig. 7 showing the relationship of the parts after the die operation shown in Fig. 6;

Fig. 10 is a section on the line 10-10 of Fig. 9;

Figs. 11 and 12 are sections parallel to the ironing surfaces through one of the heel corners showing the relationships of the parts prior and subsequent to the die operations shown in Fig. 6;

Fig. 13 shows the sole plate after the flange of the shell has been completely ironed in agains the side walls of the body;

Fig. '14 is a section on the line '14-14 of Fig.13;

Fig. 15 is a top view of the completed sole plate showing the upper edges of the flanges pressed down against the top of the body and the fillister screws inserted;

Fig. 16 is a section on the line 16-16 of Fig. 15;

Fig. 17 is a section through the sole plate parallel with the ironing surface thereof after the heating step of the method;

Fig. 18 is a top view of a modified form of sole plate, and

Fig. 19 is a section onthe line 19-19 of Fig. 18.

The present invention deals with the production of a composite sole plate as distinguished from those in which the plate is made from a single piece of metal usually cast to the desired shape. In the past, the common practice has been to cast the sole plate from gray iron or similar metal. The bottom, side wall, and a portion of the top were then ground to remove the irregularities incidental to casting and to. further shape and smoothen the casting. Following the grinding it was necessary to thoroughly polish the metal to a high degree of smoothness prior to the plating operations.

These grinding and polishing operations must be largely hand operations and consequently entail a good deal of expense. In addition to the expense involved in preparing such a sole plate, the iron from which it was made was heavy and resulted in a heavy sole plate because of the necessity of having. a comparatively thick plate of subding of the sides stantially uniform thickness to satisfactorily distribute the heat uniformly over the entire ironing surface of the sole plate and avoid hot and cold spots thereon. On the other hand, such a sole plate had a number of advantages. The metal was hard and not easily damaged through scratching and could not be easily battered out of shape when used with metal iron rests. Furthermore, the metal was easily plated and took a firm adherent coating of the plating metal. a

In the manufacture of light weight irons the tradetook to making the sole plate in the old I way by making a casting from aluminum or alumi- While such a sole plate was light in,

num alloys. weight, it still possessed the other disadvantages of the cast iron plate, and in addition, was soft and malleable so that it was easily scratched and battered in service. The aluminum plate had the further disadvantage that it was not easily plated, and that the plating, when formed, had a tendency to be cracked and chipped off in service by distortion of the soft metal beneath.

Our composite sole plate possesses the essential advantages of each of these prior plates and eliminates the disadvantages thereof. This is accomplished by making the body portion of aluminum or other light metal and the shell of steel or similar sheet metal. In this manner, we obtain a light sole plate, the outer surface of which is of steel of sufllcient thickness and hardness to withstand hard usage without scratching or deforming. By using sheet steel for the shell, we eliminate most of the grinding and polishing operations and obtain a surface which is easily plated. Furthermore, because of the substantial elimination of the grinding and polishing steps, and because of the ease of plating, we are able to produce the composite sole plate at a lower cost than those of the prior art.

One phase of the invention contemplates a method of manufacturing a composite sole plate wherein a sheet metal blank is drawn to produce a shell, means are attached to the shell for securing a body firmly against the bottom of the .shell, a filler or body is inserted in the shell, and

the flanges of the shell are ironed or formed against the sides and top of the body so as to permanently unite the body and shell. The sole plate is then heat treated to adjust the parts and prevent uneven expansion difliculties. Claims to the method are contained in a divisional application Serial No. 684,879, filed August 12, 1933.

Referring first; to Figure 1,. a blank such as shown in 'dotted lines at 21, is first out of sheet metal. This blank is then formed by suitable forming dies to a shell having a base 22 andv flanged peripheral walls consisting of side walls 23 and 24 and a rear wall 25, the flange being continuous andthe walls being connected at the point 26 and at the heel corners 2'7 and 28. The next step consists in securing to the base of the shell a plurality of wide bottomed bosses such as shown to advantage in Fig. 3. Each of these bosses is provided with a flanged bottom 30 having a plurality of projections 30 arranged to function in the welding of the bosses to the shell. These bosses serve for the attachment of the body to the base I of the shell and also for the attachment to the sole plate of the superimposed portions of the iron.

,Advantageously the bosses may be welded by means of spot welding to the inside-,of the shell and bosses 29- should be spaced from the side edges of the shell and arranged therealong in the manner shown in Figure 1. The bosses 31,

32,'and 33 are somewhat larger than the bosses 29 and serve to receive bolts for attaching the thereby facilitating the transfer of heat from the body to the base of the shell. Furthermore, the bosses should have a relatively wide area in contact with the base of the shell so as to prevent distortion of the shell upon thermal expansion of'the sole plate, as will presently be more fully discussed.

A body 34 is then positioned on the base 22 of the shell within the flange periphery. This body may take a wide variety of forms within the contemplation of the invention. In this instance, it consists of a casting of one piece, though it will be understood that the invention is by no means limited toa one-piece casting since a laminated body such as shown in U. S. Patents 1,749,596 and 1,749,597 issued March 4, 1932, to one of us may also be used. Likewise, the body may advantageously be of aluminum or aluminum alloy to provide a light weight sole plate, though here again it will be understood that any suitable metal may be employed. In the form shown in the drawings, the side walls of the sole plate are intended to slope inward from bottom to top and consequently the side walls 35 and 36 of the body are correspondingly sloped and terminated at their upper edge. in a marginal recess 3'7 on the upper surface of the body, this marginal recess being of a thickness to receive the upper edge of the shell flange so as to provide a substantially smooth upper surface on the completed sole plate and to permit a clamping action of the shell upon the body. When the construction of the iron warrants it, the body may also be provided with an opening 38 for the reception of the thermostatic element of the iron, not shown, so that the thermostatic element may be placed in close proximity to the ironing surface of the sole plate. A slot 39 extends from the opening 38 through the heel of the body separating the rear end of the body into two arms which may move toward and away from each other in response to the thermal changes of the iron. The lower surface of the body is curved, laterally and longitudinally, as best shown in Fig 5,' this curvature being such that when the shell is tightly formed around'the body and the sole plate heated to the operating temperature, the difference in the rate of expansion of the shell and the body will cause the lower surface of the sole plate to become less convex and approach planeness, it bein'g -prefe erable that the surface still remain slightly convex in order to insure against a possibility of the surfacebecoming concave on heating and also because the iron appears to operate better under such circumstances. The body 34 is provided with openings 41 for the reception of the bosses 29 and with openings 42 for the reception of the bosses 31, 32 and 33. The openings 41 and 42 are counterbored at top and bottom, as shown at 43 and'44, the counterbore 44 being of a thickness to just receive the wide flanged bottom of the bosses so that when screws are inserted in the bosses man cannot tighten the screws sufficiently to draw in the shell or loosen the'weld, nor can thermal expansion of the body accomplish the same thing. The openings 41 and 42 and the counterbores 43 and 44 are of slightly larger size than required for the reception of the bosses and screws, thereby permitting a certain amount of movement between the body and the shell and allowing sufilcient room to take care of a different rate of expansion of the various parts. The body is slotted from its periphery inward, as shown at 45, 46 and 47, the slots being adjacent to each corner of the body and openings 48 are positioned in the slots intermediate their ends, these openings being tapered inward from top to bottom of the body, When the body is of aluminum or other soft metal we have'found it advisable to provide protrusions on the body, such as shown at 49 and 51, to prevent distortion of the side walls of the body when the corner forming dies press the flange of the shell against the body, these protrusions flattening out during this die operation to provide a smooth side wall, as shown a in Figs. 9 and 12.

It is desirable that the sides of the sole plate be at an acute angle with respect to the ironing.

surface thereof because of the greater facility with which the edge of the iron can be 'moved under ruiiies, buttons, and other projections when ironing. The forming of the shell along which is done under considerable pressure.

When a-body of soft material is used it is advisable to provide the protrusions 49 and 51 to prevent the side walls of the body from being pressed out of the desired shape by the pressure of the die operations at the corners of the shell.

Referring again'to the forming operations, the body is inserted in the shell with the bosses in the openings 41 and 42. The assembled sole plate is then subjected to a die operation to bend the flanged side walls 23 and 24 from the position shown in Figure 1 to theposition shown in Fig. 4, theside walls of the body providing lateral support during the forming operation, and pins preferably on the dies being inserted in the openings 48 of the slots to prevent these slots from collapsingor closing during the die operation. The openings 48 are tapered to facilitate the entry of the pins. This die operation also serves to partially form the corners of the shell, as shown in the-latter figure. Care is taken, however, to prevent the corners from being bent up too far by the insertion of wedges between the body and the flange at the corners. The relative amount of forming of the sides and the corners is shown to advantage in Fig. 5.

The result of the next die operation is shown in Fig. 6 and the manner of performing this operation is shown diagrammatically by the dotted lines representing portions of the dies. In this instance, the dies operate at each corner bringing the lower part of the flange up against the corners of the body. 'At the same time, the

protrusions 49 and 51 are flattened out-or ironed into the body by the force of the die operation.

Figs. '7 and 8 show the point of the sole plate prior to this-die operation, whereas Figs. 9 and 10 show the point subsequent to the die operation clearly showing the manner inwhich the'sheet metal flange is pressed firmly against the side walls of the body. Likewise, Figs. 11 and 12 show one of the heel corners before this die operation and subsequent thereto.

After the corners of the shell have been brought up against the body, as shown in Fig. 6,

3 the sole plateis subjected to the action of an additional die wherein the side walls 23, 24 and 25 of the flange,.together with the upper portions.

of the corners thereof, are pressed inward,- the I metal being simultaneously contracted along the sides of the flange during this die operation, the operation resulting in a structure such as shown in Figs. 13 and 14. After this die operation there may be some clearance in places between, the flange and the side walls of the body portion such as sh wn in Fig.'14 and there would usually be a certain amountof clearance between the basely against the side walls of the body portion and the upper edge of the flange is bent down into the recess 37, thus completing theforming operations of the sole plate. In each die operation, pins are inserted in the openings 48 in the slots v45, 46 and 47 to prevent thecollapse or closing of these slots under the pressure of the, dies..

In many instances, a sole plate made in accordance with the method spfar described, will prove satisfactory, the slots in the body compensating sufliciently for the differences in expansion of the body and shell. However, it has been found that frequently when an iron embodying such a sole plate'is put into service small cracks tween the body and the shell, the body exerting undue pressure against} the side walls of the shell. This condition is particularly aggravated when the shell is made of sheet iron and the body of aluminum or aluminum alloy, the difference in expansion of these two metals tending to break the corners of the shell. however, that if the sole plate, as it comes from the last die operation; is placedin an oven or furnace and heated to a temperature slightly above the maximum temperature reached by the sole plate during normal operations, the slots 45, 46 and 47 will become partly closed, as shown in Fig. 15, thus apparently leaving space between the side walls of the shell and the body for the normal expansion of the body during the use of the iron. This condition is illustrated in Fig. 17 wherein the numeral 52 indicates the space adjacent to the heel corners of the iron resulting from the distortion of thebody by the heat treatment, whereas the numeral 53 designates the space near the point of the iron formed in the same manner. We wish it to be understood that Fig. 17 is merely illustrative of the principle-involved and .is not to be construed as a limitation as to the precise relationships between the body and the shell which corrects for the difference in expansion between the two metals.

After the heat treatment of the sole plate and after parts have returned to normal temperature, (the corner portions being in the displaced condi- We have discovered,

tion shown in Fig. 1'1), "illlister head screws 54 the screws eing drawn up tight,thereby drawing the base of the shell firmly against the lower side of the body to maintain intimate contact therebetween for maximum heat transfer between the parts. I

Figs. 18 and 19 show an additional way in which the base of the shell may be held firmly against the bottom of the body. In this instance, a curved slot 55 is formed in the body substantially evenly spaced'from one edge of the body throughout its length. If desired, this slot may be caused to intersect the periphery of the body as shown at 56 to form one of the desired expansion slots. An'angle iron strip 57 is welded, or otherwise attached, to the upper surface of the base of the shell and projects upward through the opening 55, the body being provided with a countersink 58 for the purpose of receiving one side of the strip. The upper edge of the strip is then bent over into a countersink 59 on the top side of the body, thus holding the base of the shell firmly up against the body. It isdesirable that the opennig 55 be of such width as to permit the strip to rest at a slight angle: with respect to the vertical, as shown in Fig. 19, so that 'upon expension of the body the strip may spring sidewise. The upper edge of the strip may advantageously be slotted, as shown at 61, to give greater elasticity. Likewise, a strip 62 is secured in a vcomplemental slot 63 Spaced from the opposite.

edge of the body. If desired, similar strips 64 and 65 may bepositioned in the well 38 and clamped structure for differences in thermal expansion between the body and the shell. This difference in expansion will, in part, be accounted for by the difierencein temperature normally existing between the body and the shell, the heating element of the iron normally being supported di rectly on the body whereas the shell is exposed to the cooling effects of the air. For this reason, the body will normally be at ahigher temperature than the shell, and consequently will expandto a greater extent when the iron is in service.

When the body is made of aluminum or aluminum alloy, this condition is aggravated by-the' greater coeflicient of expansion of the aluminum.

However, by providing the slots in the body, and

subjecting the sole plate to the heat treatment previously described, we are enabled to bring about a condition in the sole plate such that the difference in expansion between the component parts thereof is rendered harmless and at no time in thenormal operation of the iron will the body exert undue pressure outwardly against the side This feature is of greatest advantage'when the sole plate forms a part of an automatic iron wherein the ironing surface is maintained at a substantially uniform normal operating temperature.

stances the sole plate is preheated to a certain Under. such circumhigher temperature to allow a safety factor for overrunin temperatureof the iron. Likewise, by providing the body with a convex face we provide means for counteracting the normal tendency of the shell to curl since the lateral expansion of the aluminum body will be greater than the expansion of the steel shell, heating of the sole plate will bring about the straightening of the convex surface to nearly a flat surface on the bottom of the sole plate, when the iron is in service. 5

Attention is also directed to the shape of the bosses, which are welded or attached to the base of the shell. It will be seen that these are provided with flanged or disc-like bottoms so that they cover arelatively large area on the bottom 10 of the insert. Likewise, the body is counterbored to a depth justsufiicient to receive this disc-like bottom of the flange. Thus, when the body thickens through expansion, the bottoms of the bosses merely draw up against the body, the strain 15 caused by the expansion thus being taken between the fillisterhead of the screw and the base of the boss. If instead of the large bases, straight bosses or nipples were used without any flange, the body would, when on heat, exert an upward pressure 20 on the fillister head screws, due to the expansion of the metal and would pull the straight round boss up through the hole of the body, thus causing the outer shell to follow through the hole, which would show a small depression on the outer 25 surface of the base of the shell. On the other hand, with our present construction, this becomes impossible and it is impossible to visually detect from the outside of the sole plate the points at which the bosses are welded to the shell.

Through this construction we are enabled to produce a relatively light sole plate having the advantage of the greater heat conductivity of aluminum and yet retain the surface hardness resulting from the steel shell. In other words, 35

when a steel sole plate is used, the sole plate is relatively heavy though it possesses the requisite hardness, whereas when an aluminum sole plate is used the article is light in weight, possesses greater heat conductivity than the steel article 40 but is so soft that it is readily scratched-or deformed. We have succeeded in combining the advantages of these two forms of sole plate and a in eliminating the disadvantages of each. Furthermore, through our construction we have elim- '5 inated-the necessity fora large amount of polishing and grinding both on the ironing surface of the plate and the side walls thereof, thus ma terially reducing the cost of manufacture of the sole plate.

By the method disclosed, we have succeeded in forming the steel shell around the body by means a specific embodiment of our invention, we are aware that numerous alterations and changes may be made therein within the spirit of the invention and the scope of the appended claims, in which i We claim:

1. A composite sole plate for sadirons of the type having means for controlling normal operating' temperature, comprising -a body, and a sheet steel shell covering, the lower face of the. body and formed over the bottom edge and sides of the body,-the body being slotted along its edge so that at no time in the normal operation within the. temperature contrplled range will the corners of the. body exert undue pressure outwardly against said formed side walls of the shell.

exerting undue 2. A composite sole plate for sadirons compr ing a body of metal having inwardly inclined sides, and a shell of sheet metal covering the lower facev of the body and having sides formed jtorted at. the corners so as to partially close said slots and leave a space between the side walls of said shell and said body to compensate for the diiference in expansion between the shell and the against said sides of the body, the co-eflicient of body expansion of the body metal being. greater than that of the shell, and the body having slots pre'-.

venting the corner portions of the body from pressure outwardly against the expansion during normal operaplate for sadirons comprisshell by thermal tion.

3. A composite .sole

ing a body of material-having inwardlyinclinedsides, a shell ofsheet metal covering the lower face 'of the body and having sides formed against said sides of the body, the coeilicient of expansion of the body material being greater than that of the shell, and means uniting the shell bottom to the body over a substantially central area, the body having slots which compensate for thermal expansion between said central area and the corner portions of the body whereby at no, time in the normal operation will the comers of the body exert undue pressure outwardly against the shell.

4. A composite sole plate for sadirons of the type having means for controlling the service temperature thereof comprising a body and a sheet steel shell formed thereon, the body having a greater coeflicient ofexpansion than the shell and the bottom of the body and shell having a convex curvature. longitudinally and 1 laterally when cold, the difference in the rate of expansion of the body and-shell causing theconvexity to be reduced in the service temperature of the iron.

, 5. A soleplate for sadirons comprising a body,

a sheet metal'shell formed thereon,'a plurality.

ofa body, a sheet metal shell formed thereon,.

- the body being of a material having materially greater coefficient of expansion than the shell.

and a plurality of body elements'attached to the base of the shell and extending into the body, said body having openings for the reception of saidelements of a size greater than required so as to permit relative movement between the body and the elements with thermal changes thereof.

7. The combination in a sole plate for sadirons of a body, a sheet metal shell formed thereon, a pluralityofbody securing elements attached to the base of the shell and extending into the body, the body having openings for the. reception of said elements of a size greater than required so as to permit relative movement-between the body and the shell with thermal changes thereof, and means for preventing the outer surface of the shell from being depressed by being drawn into v the openings inthe body upon thermal expansion of the latter.

8. A sole plate for sadirons comprising a body, a sheet metal shell having flanged sides formed on said body, said body having a plurality of diagonally positioned slots extending inwardly from the periphery thereof. the body being disin expansion between metal I 9. sole plate for sadirons comprising a body,

a sheet metal shell having a flange formed against the side walls of the body, a plurality of wide base bosses attached to the base of said shell and extending into the body, said body having openings for the reception of said bosses and abutments for the bases thereof, and a plurality of screws 1 in said bosses for securing and said body together.

10. A sole plate for sadirons comprising a body, a sheet metal shell formed thereon, a plurality of the base of .saidshell angle strips attached to the base of said shell intermediate the'sides thereof, said body having slots for the reception of said strips, said' strips being bent over against the top of said body to clinch the base of said shell against said body.

11.. In a composite sole plate for sadirons'having a body and a sheet metal shell formed thereon, means for securing the base .of the shell against the body comprisingspaced bosses weld-- ed'to thebase, said bosses being receivable in bores in the body, and means for preventing the base at-the point where the bosses are welded thereto from being drawn out of-alignment by thermal expansion of the body.

12. In a composite sole plate for sadirons having a body and a sheet metal shell formed thereon, means for securing the base of the shell against the body comprising spaced b'osses having wideflanges welded to thbase, said bosses being receivable in bores in the body and the flanges being receivable in counterbores in the body .01 a thickness substantially equal to the thickness of, the flanges, and screws in the .bores' receivable in the bosses to' draw the base of the shell against the boihr.

13. A composite sole plate for sadirons comprising a body having a lower surface and a sheet metal shell formed thereon having a base in contact with said surface, said body and shell being formed of metals of different coefllcients 'of expension, and having a curvature when cold, the curvature-being such that the difference in the rate of expansion brings said surface and base plane substantially at the service temperature of said iron. v

14. A composite sole plate' for sadirons comprising a body of, metal high in aluminum having a convex lower surface, a sheet metal shell formed thereon having a base held against said convex surface, the curvature of said surface being such that the difference in thermal expansion of said members cause said surface and said base to become substantially plane at the service temperature of the sole plate. 1

15. A composite sole plate for sadirons comprising a body, a sheet steel shell covering the lower i'ace'of' the body and formed over the sides of the body. and means over a central area of the body and shell uniting the two, the body having slots 'for preventing it from exerting sufficient pressure outwardly against the shell to crack the body.

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of the shell by thermal expansion of the

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