US2423863A

US2423863A - Sheet metal compartment with shelf supports and method of manufacture

Info

Publication number: US2423863A
Application number: US365949A
Authority: US
Inventors: George F Wales
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-11-16
Filing date: 1940-11-16
Publication date: 1947-07-15
Anticipated expiration: 1964-07-15

Description

July 15, 1947.

ca. F. WALES SHEET METAL C OIPARTHENT WITH SHELF SUPPORT; AND METHOD oF MANUFAGTURE Filed Nov. 16, 1940 3 Sheets-Sheet 1 July 15, 1 947. G, F, WALES l 2,423,863

SHEET ETAL COIPARTMENT` WITH SHELF SUPPORTS AND METHOD 0F MANUFACTURE Filed Nov. 16,' 1940 sheets-sheet 2 ,4 Trae/vf V5.

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I July l5, r F, WALES l v2,423,863

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I Patented July 15, 1947 OFFICE SHEET METAL coMrAaTMENT wrTn SHELF surroa'rs AND METHOD oF MANUFACTURE George F. Wales, Kenmore, N. Y. Application November 18, 1940, Serial No. 365,949

(Cl. S12-141) 12 claims. l

This invention relates to improvements in metal containers provided with shelves, racks or the like arranged to slide into andout of said containers, and more particularly this invention relates to rails or supports for the slidable shelves or racks, and to methods of making container side walls having rails or supports for such shelves, racks, or the like.

Various constructions have heretofore been used for providing rails or supports for slidable shelves, racks, drawers, and the like, one of these being in the form of independent channels which were. spot welded to the sides of a container at equal heights so that a rack or shelf would slide in the channel. Considerable difficulty has been experienced in making these channels in pairs so that they are duplicates and in spot welding them in the exact relationship required so that they would support the shelves or racks horizontally in parallel relation to the bottom of the container.

With these channels, it was also necessary to weld a clip or otherwise provide a stop to the channel or container which would prevent the shelf from being inadvertently pulled completely out of the container. Other constructions require the metal of the sides of the containers` to be severely stretched, for example, by providing knob-like extensions at intervals on the sides of the container to provide intermittent bearings for the rack or shelf, and according toanother construction, rails were drawn directly into the container sides by stretching the metal of the side walls. These drawn constructions are expensive in that they require more than one operation on the metal and do no produce thebest results.

One of the objects of this invention is to provide a container with rails or supports of improved and simplified construction on the sides thereof. It is also an object of thislinvention to provide rails or supports of improved construction in which sharp corners or recesses are eliminated to the maximum extent to facilitate the cleaning of the container. on which the rails or supports are formed. A further object of this invention is to provide a container of this type with rails or supports which are formed integral with the container sides by forming the metal without stretching or weakening the same.

Another object of this invention is to provide an improvedvprocess for making container sides having my improved rails or supports formed thereon. A further object is to .provide an improved process of forming rails or supports in container sides so that they are accurately positioned with relation to the lower edges of the container sides.

Another object of this invention is to provide rails or supports for shelves or racks, in which the rails are provided with integrally formed stops to limit the extent to which a shelf or rack may be Ipulled out of the container. A further object is to provide a process for making such stops and for readily changing the positions of the stops with reference to the rail or support.

Other objects of this invention willappear from the following description and claims.

In the accompanying drawings:

Fig. l is a plan view of a flat sheet metal panel from which container sides embodying this invention may be made.

Fig. 2 is a fragmentary view of the same panel after the longitudinal edges thereof have been bent over and after the shelf supports or rails have been formed in the panel. l

Fig. 3 is a fragmentary perspective view showing an edge portion of the panel before the rails or supports have been formed therein.

Fig. 4 is a similar view thereof after the rails or supports have been formed therein.

Fig. 5 is a fragmentary perspective view of the rear portion of' a side ,of a container showing it positioned with relation to the back of the container.

Fig. 6 is a fragmentary perspective view of the rear portion of a sheet before forming the rails or supports therein, the view 'being taken from the rear looking forwardly.

Fig. '1 is a similar view of the same sheet after forming the rails or supports therein.

Fig. 8 is a fragmentary front elevation, partly in section, of the four Walls of the container in assembled relation to each other.

Fig. 9' is a sectional elevation of a pair of cooperating dies for use in forming the rails or supports.

Fig. 10 is a fragmentary top plan view, on an enlarged scale, of a container side wall and showing the same inoperative relation to a portion of the die for forming a rail or support therefor.

Fig. 11 is a fragmentary elevation, partly in section, of the die showing the .parts of the same in the position which they occupy when completing the forming of a rail or support in the side of a container.

Fig. 12 is a transverse section of the rail forming die showing the mechanism for forming the stops in the rails.

In the accompanying drawings, my invention is illustrated as sed in connection with the inner Wall or liner of an oven of a cooking range. but it will be understood that the invention is equally applicable to forming side walls of containers of any other type provided with rails or supports for slidable shelves, racks, drawers, or the like. I have also shown my invention as ap-4 plied to a container or oven` liner in which the two sides, the top and the bottom, are formed of a single sheet of metal, but it will be obvious that this invention is equally applicable to a container in which the side walls are formed l Y 3 separately from the top and bottom of the container.

In the accompanying'drawings, Fig. 1 shows a panel or sheet of metal I4 .of sufficient size to form the ,right and left sides I5 and I6, the top I1 and the bottom I8 vof a container. After the sheet of metal, which may, for example, be enameling iron, has been cut to the right di mensions, it is subjected to the action of a series of notching dies which provide the sides I5 and I6 of the sheet with notches 20 and 2l. These notches are formed at thefront of the two side walls I5 and I6. These notches are accurately positioned on the sheet so that each notch 20 on the front edge of the sheet has a corresponding notch 2l accurately located at the rear edge of the sheet. One pair of notches 20 and 2| is provided for each rail or support desired. If my invention is to be used in connection with oven liners, it may be desirable .to provide the front and rear edges of the oven liners with outwardly extending ilanges by means of `which. the front edge of the liner may be secured to the door frame of the oven, and the rear edge of the liner to the back wall of the oven. It may also be desirable to provide V- shaped notches 22 extending inwardly to the depth of the flanges to be formed. Another iiange 24 may also be desired at an end of the panel and corner notches 25 are, consequently, provided at the front and rear ends of the ilange 24. Preferably all of these notches are simultaneously formed in a single operation `on a punch press by means of suitable dies. The upright or vertical broken lines in Fig. sent the lines on which the front and rear edges of the panel are to be bent to form the flanges, and it will be noted that the notches 20, 2| extend inwardlybeyond these lines. The extent to which these notches extend inwardly beyond the ylines of fold depends upon where the ends of the rails are to be, the notches extending into close proximity to the ends of the rails. The

horizontal broken lines in Figs; 1 and 2 indicate the lines along which the metal is folded to form the four sides of the container.

It may also be vdesirable to provide certain holes or apertures in the ilange portions of the panel through which bolts, rivets, or the like,

may be passed for securing the oven liner to the door frame or oven back, and if desired, such holes 21 may be formed in a punching operation after the notching operation, or if desired, some or all of these holes may be formed at the same time that the panel is notched.

After the panel has been notched and the desired holes punched therein, the side flanges may be bent outwardly to occupy positions kat approximately a right angle from the main body portion of the paneL'as clearly shown in Fig. 3. The panel is then ready for the formation of the rails or supports, which are formed one at a time by means of a suitable die, and the companion notches 20 and 2| may serve as locating means for correctly positioning the panel'on the die. Since these notches can readily be `placed with1 great accuracy in the desired" positions, it will follow that by using these notches as guide means the rails or supports can also be formed accurately in the desired locations and parallel toeach other. l

The rails or supports are formed by bending portions of the metal of the sides of the containers into a substantially channel-shaped form, as indicated at 30, `without stretching the and rear edges 1 repremetal or reducing the thickness thereof. Consequently, when the metal is bent to form the channel or trough-shapedrailsjor corrugations 30, the notches 20 are contracted and, if desired, the notches 20 may be so proportioned with reference to the rails that the edges of the notches are brought together when the rail is formed, as clearly shown in Fig. 4, so that the notch 20 appears as a slit 3|. At the front of the container, it is also desirable to close the iront ends of the channel-shaped rails 3D and this is done during the folding or drawing operation by folding the metal at the end of the channel-shaped rails 30 from the peaks of the rails or corrugations across the endsthereof so as to form rounded closed ends 32. By `drawing l,the metal at least in part over the ends of the rails as shown in Fig. 4, the opening of the slits 3| is prevented, so that welding or other means for securing together the meeting edges at the slits is not necessary. The rear ends of the channel-shaped -rails 30 may be similarly formed, if desired, as shown in Fig. 2, or if it is desired to -have the rails abut squarely against a back Wall 33 0f the container, the rear ends Y of the channels forming the rails may be left open, as indicated at 34 in Fig.`7. In this construction, the back wall 33 has ay rearwardly turned edge flange 35, and when' this type `of back is used, the rear edge of the panel is not bent but extends straight rearwardly so that it may be spot welded or otherwise secured to the flange .35 of the back wall. By'means of this construction, the back wall 33 closes the open ends 34 of the channel-shaped rails. In order to facilitate the manufacture of these open-ended rails, the notches 2| may be made slightly wider than the notches 20 of the front edge, and consequently, when these rails.30 are finished, there will still be gaps or notches 31 in the rear edge portions of the side walls.

Mechanism of any suitable o r desired type may be employed for forming the channels which serve as rails or supports for the metal. In the construction shown in Figs. 9 to 12, a die set is shown, which is suitable for formingA theseA rails, .but other means for producing the same may be employed, if desired. In the construction illustrated, 4B represents a. punch which is shaped to form the interior of thechannel-shaped rails 30, and 4I represents a die having a groove'or recess 42 formed therein, which is shaped in accordance with the outer surface of the rail. In theparticular die shown, both ends of the punch Ml and groove 42 are rounded so as to produce vrounded ends 32 at both the front and rear ends ofthe rails, but as vhereinafter explained, the same die set may be employed forforming rails having one or both ends thereofl open. The punch cooper ates with a pressure Dad or plate 43 which `is nor, mally held by springs 45 in a position in which the top surface thereof is approximately o'n the same level as the upper face of the'purichqjas panel I4 may engage for correctly positioning the panel with reference to the die. l

It will also be noted that the slits or notches in the metal terminate -at a short distance from the corresponding rounded end o! the punch 4l. Consequently, when the metal is formed, which happens when the die 4I 4descends into enmement with the punch 46, the short portion oi met'al located between the end of the punch and the metal in the sheet becomes formed over the end of the punch as the punchenters into the groove 42 of the die. This also contracts the notches in opposite ends of the panel I4. In the case of the die shown in Fig. 9, this turning down of the metal over the ends of the punch occurs on both sides of the die. It will be obvious, however, that if the panel same forming action Y or metal sheet of asmaller vdimension from the front to the rear edges thereof is acted on by the die set shown in Fig. 9, then since the punch is longer than this dimension'of the metal, there will be no metal at one of the rounded ends of the punch, and consequently. the metal at this end of the punch will be shaped to form a rail with an open end 34, as shown in Figs. 5 and '1. The same dietherefore. can be used to form rails or supports oi' eitherof the two types shown. When open-ended rails are formed with this 4die set, the notches in the panel at the open ends of the rails must be somewhat wider than the notches at the closed ends of the rails, since the former notches, after being contracted by the `forming of the rails, must be of a width at least equal to the width of the punch 40.

The die is preferably also provided with means for accurately positioning the work or panel I4 relatively to the die mechanism shown in Figs. 9 to 12, and this is done by providing beyond the opposite ends of the punch 49 movable positioning members which are of such width as to enter into the no'tches at opposite sides of the panel when -the panel is correctlyposltloned in the die set. In the construction shown for this purpose, the pressure pad 43 of the lower die member is provided beyond the ends of the punch with grooves or recesses 46, extending transversely of the punch 40, the walls or edge portions 44 each forming one edge of these grooves. Each of these grooves has a slidable positioning member 48 arranged therein to slide into and out of engagement with the wall or edge portion 44 of the groove. These members 48 may be guided in their movement toward and from the walls 44 in any suitable manner, for example, by means of undercut guide members 49 suitably secured in the recesses 46. The slide members -are urged by means of springs 50 into engagement with the walls 44 of the grooves 46. Each slide is of a width just suflicient to enter into a notch of the panel. Consequently, when it is desired to position a panel in the forming die, lthe panel is placed on the punch 49 so that the anges or turned-over edges of the plate extend downwardly into the grooves 46 and contact with the inner walls 44 of these grooves. The panel I4 is then moved lengthwise until the` two oppositely arranged notches are in registration with the two slides 49, whereupon the panel will drop as the slides enter the notches. When thus positioned, the panel is ready for the forming operation which has been described.

Means must, of course, be employed to remove the slide members 49 from the notches before the forming operation begins so that these slides will 6 f v suitable or desired means may be provided for moving these slides out of their normal positions shown in Fig. 9, and for this purpose, each slide is provided with an upwardly extending portion 62, which is adapted to be engaged by the die 4I during its descent to move the slide members out of their normal positions. lThis movement may be accomplished in any desired manner. for example, by means o! inclined or beveled faces on the slide members which are positioned so that they are engaged by correspondingly beveled faces 63 of the die 4| when the die descends toward the punch and theengagement of these inclined faces will cause the slides to move outwardly against the action of the springs 69, and out of the notches in the panel, so that the panel 4I is released by the slides 49 just before the die 4I engages the panel I4 to start the folding operation. rThe.panel positioning means described are illustrated merely by way of example, since it will be obvious that any other means for correctly positioning the panel relatively to the forming dies may be employed. If one edge of the panel is not provided with a bent-over flange, as shown in Figs. 5 to '7, a slidable positioning member similar to that illustrated may be employed, but which is turned to slide vertically instead of horizontally.

When rails or supports of this type are used in ovens or food containers having slidable shelves or racks, it may be desirable to provide below each rail some form of stop means to limit the extent to which a shelf or rack may be pulled outwardly. Generally these stops are provided below the rail or support and engage a rearwardly projecting stop part on the shelf or rack when the shelf is in approximately horizontal position. If it is desired to remove the shelf or rack from a pair of supports or rails, then the front end of the shelf or rack is swung upwardly to enable the stop thereon to disengage the stop. Similarly when a rack or shelf is in this inclined position, it may also be moved into operative relation to another l pair of rails or supports.

| I have provided an improved stop device for use in connection with my improved rails or supports, which is formed integral therewith and with the sides I5 and I6 of the container. Stops are, consequently, formed out of the metal of the panel or container side during the folding or forming operation,A and consequently, these stops are of a very sturdy construction and are also preferably curved or rounded in such a. manner that they can be easily kept clean. It will be noted, however, that these stops must be formed on the lower edges only of the rails or supports, and consequently, if the container is formed of a single panel folded to form four sides thereof, the stops 60 on the portion I6 of the panel must extend in the opposite direction from the stops 6I) of the part I5 of the panel, as, clearly shown in Fig. 2. Similarly, if the sides of the container are formed of separate pieces or panels, the panel for theright side of the container must be formed diiferently than the panel for the left side, so that all the stops will be arranged at the same distance from the front ends of the side walls of the container and below the rails. It is, consequently, necessary to provide means for forming these stops at either side of a rail or support.

Any suitable means may be provided for forming these stops, and in the construction illustrated, I have provided the upper die 4I with oppositely arranged recesses 6I and 62 extending not prevent the contracting of the notches. Any 'l5 outwardly in opposite .directions from opposite `'moved-'into an upper position to enter into a stop forming recess of the die. As shown in Fig. 12, the nger 65 is arranged in its upper position, so

that the top edge thereof is substantially at the level of the top edge of the punch 40 yand so that .it will enter into the recess 62 of the upper die 4|, and the other nger 64 in Fig. 12 is shown in a lower position, in which it does not act upon the panel i4. Consequently, when the metal is folded to form the rails or supports, one of the fingers 54 or 65 `will press some of the metal of the panel into the corresponding recess to form a stop li.k

As the panel is fed between the punch 40 and die f3! to form the rails or supports 30, one at a time, the operator must change the positions of the punch iingers 64 and G5 as the panel progresses between the dies. For example, with the panel shown in Fig. 2, after the four stops 60 are formed on the portion I 5 of the panel, the fingers 66 and 65 mus-t be alternated to form the stops 6i) on the rails 'on the part I6 of the panel. Any

suitable quickly operating mechanism may be employed for this purpose, and in the construction illustrated, the two

punch fingers

64 and 65 are guided for vertical movement incorrespondingly shaped recesses formed in the pressure pad 43 of the lower die. Below this pad, I provide a slide 10 which may be suitably guided for movement in a direction lengthwise of the punch 40 and the lower ends of the

fingers

64 and 65 cooperate with cam faces of this slide 1U. The slide may, for example, be provided with a cam-shaped upper face including an inclined part 1| leading toa raised part 'l2 of the slide 10, which cooperates with the finger 65 in such a manner that when the slide is in the position shown in Fig. 9, the nger 65 is in its elevated position. The cam face of the slide includes another inclined portion i3 shown in broken lines in Fig. to a raised portion 'I4 and cooperates With the other finger 64. The two raised portions 12 and i4 are spaced fr0-m eachother on the slide 10 in such a manner that when one finger is raised,

9, which leads the other one will be lowered and vice versa. 'Ihe y -slide may be moved inwardly and. outwardly by any suitable or desired means, for example, by means of a lever or handle 15, Fig. 9, connected to one end of the slide. Consequently, in the use of this die for forming the rails or supports shown in Fig. 2, the slide 10 will be moved into one position during the forming of the four rails and stops on one side Wall of the container, and the slide 'l0 will be moved to the other end of its movement for changing the fingers to form the stops on the other side wall.

It is, of course, unnecessary to provide any means for closing the recess 6| or 62 in the upper die 4| when the same is not being used, since the metal of the panel I4 bridges across this gap or recess, as clearly shown in Fig. 12.

Container walls provided with rails such as herein described have the advantage that they are strong and durable in construction. Byforming the metal as herein described without stretching the same, but by merely folding or bending the metal to form the rails, the metal of door frames or rear walls,

.side walls provided with rails the rails will not be weakened at any portion thereof and will have the metal at all parts of the rail substantially of the same thickness as at other portions of theside wall of the container. Furthermore, by means of my construction, the ends of these channel-shaped rails can be closed by metal formed over these ends, and by making the notchesin the metal before forming, a smooth and substantially uninterrupted surface is formed which has no sharp corners and can, therefore, .be easily cleaned. The bending of the metal to form the rails is easily eiiected in a single operation, whereas when rails are formed by stretching the metal, several operations are usually required .to form rails of the necessary depth. The slits formed in the metal may be secured together by welding or other means, but in most cases, this is not necessary. Since in many cases, containers of this kind are covered with a vitreous enamel,

this enamel iills the small slits which remain after the notches have been contracted, Kas shown in Fig. 8. Stops formed in accordance with my invention, are of very strong and rigid construction, and since they are formed in the same operation with the forming of the rails, they do not add to the cost of making the container sides, except for the slight additional initial die cost.

By forming the metal of the peaks of the rails at least partly across the end-s of the rails in a directional; a right angle to the sheet, the ends of the rails will be at least partly closed by integral unslitted end portions which bridge the two sides of the rails and thus prevent them from separating or spreading apart. This construction, consequently, also keeps the metal at the slits 3l from separating, and thus produces a rigid and strong structure without welding.

When container side walls constructed as herein disclosed areused in the liner of an oven, these wa11s have the advantage of materially increasing the surface through which heat transferred from the hot gases surrounding the oven to the interior of the `oven may take place. The area of the as herein described is increased bythe amount of metal bent or folded inwardly to form the rails.

In accordance with my invention, the rails may be of any desired depth, there being no limit to the extent to which these rails may be folded or bent inwardly, since the metal is not stretched or drawn by this folding operation.

By notching the edge portions of the panel and forming the rails between notches, it is possible to make side walls of containers with their front and rear edges at or uncorrugated, so that they may be easily secured to other members, such as to make a substantially tight joint therewith. I, therefore, obtain the advantages of a corrugated sheet -without the .disadvantage of having the corrugations extend from edge 'to edge of the sheet.

I claim as my invention:

l. A sheet metal oven interior comprising two sides, a top, a bottom, and a back, said sides in- Cluding integral pairs of rack supports projecting inwardly at spaced levels above the bottom, said supports terminating short of the rear edges of the' sides to provide substantially hat rear por tions on said sides, said back having flanges eX- tending rearwardly therefrom .and which are secured to said rear portions with said back abutting against the rear ends of said rack supports.

2. A sheet metal oven interiorcomprising two sides, a top, a bottom; and a back, said sides including pairs of rack-supporting rails formed by 9 bending portions of the sides into substantially channel form, Vsaid rails projecting inwardly at spaced levels above the botto said supporting,

-which comprises;I first, cutting a pair of notches,

onein the front and one in the back edge portions of a. rectangular blank at each portion where a support is to be formed, the two notches of any pair being arranged directly opposite each other;

second, bending flanges along said edges rto approximately right' angles to said blank, the width of each ange being less than. the depth oi the notches; and third, bending the portions o the metal between the notches into substantially channel-shaped rails and simultaneously9 bringing together the opposite edges oi? the notches and working the metal adjacent the bottom edges of said notches to forni closed end walls for each rail.

4. 'I'he method of manufacturing a sheet metal compartment including a top, bottom, and side walls, all having perforated flanges iront and back, and said side walls having oppositely disposed longitudinally extending shelf supporting ledges which consists in; rst, shearing a sheet oi metal to obtains.. rectangular panel of proper size; second, cutting a ,plurality of pairs of recu tagnular shaped notches in. the front and -ioaclr edges of said panel, the two notches of any pair being arranged directly opposite each other and being positioned in alinement with the portions of the panel 'at which ledges are to be located; third, cutting a plurality of pairs of slitting notches adapted to allow the panel to bebent at right angles transversely to its length as a nal operation; fourth, perforating holes in said panel wherever desired; fth, bending seid iront and back edges to form anges at approximate right angles to said panel, the width of said anges being less than the depth of the notches; sixth, forming the portions oi the metal in alinement with said rectangular shaped notches into sub stantialiy channel-shaped ledges and simultaneously bringing the opposite edges oi. the notches toward each other and working the metal adiacentr the bottom edge of each notch to form closed end walls for each ledge; yand seventh, bending the panel transversely to its length in line with said slitting notches to iorm said panel into a compartment body with each'shelf supporting ledge of one side wall directly opposite a companion ledge on the other side wall and equally spaced above the bottom.

5. A method of manufacturing an open end container having four sides and a baci: in which the four sides comprise one integral piece of metal nandthe back another, the operations for manufacture of the integral piece consisting in; rst, cutting the blank to size; second, punching holes in the front edge and cutting out pairs of notches from the front and rear edges; third, bending a flange on'said front edge a width equal to the depth of some of the notches and less than the depth of others; fourth, forming channel-shaped rails extending partially between the latter pairs of notches and simultaneously closing in the front ends of said rails, the rear ends remaining open; fifth, bending the piece at right angles trans- 10 versely to its length in line with the pairs of the notches first mentioned, into a body portion of substantially rectangular cross sectional configuration; and sixth, mechanically attaching a back to the body insuch manner that said rear open ends of said rails are closed by said back.

. 6. A method of forming in an open ended sheet metal container having two sides, a top, and a bottom, shelf supports projecting inwardly from either side in pairs at spaced levels above said bottom, each support havinga portion thereof formed of greater width than other portions of the support and projecting downwardly'to form a stop for limiting the outward movement of a shelf sul-1-l ported on any pair oi.' supports, said method consisting in cutting out notches of metal from the front and back edges of a blank directly opposite y one another in the Portions wheresupports are to be formed, bending anges to approximately right angles to said blank along the front and back edges, then forming said supports one at a time locating from said notches and simultaneously bringing the opposite edges of the notches toward each other and working the metal adjacent the bottom edge of each notch to form closed en d walls for each support, then bending said blank into box form, the front to back corner bends being made on aline extending from other notches in said iianges to permit said forming.

7. ln sheet metal container side walls ci varylng sizes the method of forming channel-shaped raclr or shelf supporting ledges consisting in; rst,

cutting oppositely disposed pairs of rectangular shaped notches in the front and rear edges oi each side wall blank in line with the portion of said wall which is to be formed into a ledge, each front notch being inthe same relation to the front edge in any size of blank with reference to both width and depth of notch, each rear notch being in the same relation to the rear edge of said blank with reference to both width and depth of notch, said rear notches being wider than said front notches an amount equal to or greater than the inside dimansion of the formed channel; .and second, forming the portions of the metal in alinement with said notches into channel-shaped ledges and simultaneously bringing the edges of the front notches together and working the metal adjacent to the bottom edges of said front notches to form a closed front end wall for each ledge and at the same time bringing the edges of the rear notches toward each other no closer than the inside width of said channel, thereby leaving the rear end of each channel-shaped ledge open at a distance short oi the rear edge equal to the depth of the rear notch and a gap in the rear edge equal to the depth of the rear notch and of a width equal to or greater than the inside width of said channel.

8. A sheet metal oven interior comprising two sides, a top, a bottom, and'. a back, said sides including integral pairs of rack supports projecting inwardly at spaced levels above the bottom, said supports terminating short of the rear edges of the sides to provide substantially nat rear portions on said side walls, said top and bottom sections having flat. rear portions extending rearwardly the same distance as the side walls, said back having flanges on four sides extending rearwardly therefrom and which are secured to said rear portions of said sides, top, and bottom, with said back abutting against the rear ends of said panels including integral pairs of rackl supports projecting inwardly at spaced levels abovel the bottom, each of said supports terminating short of the rear edge of its side panel in such manner` said back abutting against the rear ends of said.

rackI supports.

10. A sheet metal oven interior comprising two side panels, a top, a bottom, and a back, said side panels including integral pairs of rack supports projecting inwardly at spaced levels above the bottom, each of said supports terminating short of the rear edge of its side panel in such manner that a gap, wider than said support and extending from the termination of said support to the side panel rear edge, exists at the rear of each support,

- the metal between gaps providing substantially fiat rear portions on said side pane1s,'said top and bottom sections having flat rear portions extending rearwardly substantially the same distance asv the at rear portions of the side panels, said back having anges on four sides extending rearwardly therefrom and which are secured to said rear portions of Asaid side panels, top, and bottom, with said back abutting against the rear ends of said rack supports, said supports terminating short of a ilange bent on the front edge of each of said side panels and in a separation of the metal of said flange extending parallel to and into the front end wall of each support, which end wall is completely closed.

11. In a sheet metal container side wall having a flange on the front edge formed at approximately right angles and a rearwardly extending vflange on the rear edge, a longitudinally extending shelf support including an inwardly formed part of the metal of said side wall, said support being of substantially channel-shape and closed at the front end by a wall formed from metal worked in from said end, the support rear-end being open and terminating short of the rear edge of said side wall and said rearwardly extending flange having a notch equal in width or greater ing ange inwardly to said support rear-end.

12. One or more supports for a. side wall in accordance with claim 11 and including means for closing each open end of the support by providing a back member having a flange extending rearwardly which .is secured to the rearwardly extending ange of the side wall with said back member abutting against the rear end of each of said supports.

' GEORGE F. WALES,

REFERENCES CITED .The following references are of record in the ille of this patent:

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