US2818994A - Method of making corners of sheet metal articles and article produced thereby - Google Patents

Description

Jan. 7, 1958 A. GREIG ET AL METHOD OF MAKING CORNERS 0F SHEET METAL ARTICLES AND ARTICLE PRODUCED THEREBY 2 Sheets-Sheet 1 Filed May 7, 1952 Inventors HRTHuR GREI I/YM PRICE" Attorney Jan. 7, 1958 A. GREIG ET AL METHOD OF-MAKING CORNERS 0F SHEET METAL ARTICLES AND ARTICLE PRODUCED THEREBY 2 Sheets-Sheet 2 Filed May. 7, 1952 mm m 5 l r mmw m A w RM wm T Rm 5 METT-EQD @F MAKING CORNERS OF SHEET METAL ARTHCLES AND ARTICLE PRO DUCED Arthur Greig and iiilliam Price, Perivale, Greenford, England, assignors to The Hoover Company, North Canton, (title, a corporation of Ohio Application May 7, 1957., Serial No. 286,552 Claims priority, application Great Britain May h, 1951 7 Claims. (Cl. 22ti-62) This invention relates to corners of sheet metals articles, for example the corners of a generally box-like sheet metal casing, and is concerned with the formation of corners in a sheet metal article having an inwardly offset edge forming a shoulder running round the corner. By the term offset edge is meant a marginal portion of a wall lying generally in a plane different from but parallel to that of the remainder of the wall.

According to the present invention a method of forming such a corner includes cutting away a portion of the edge where the corner is to be, and securing in the gap 21 gusset similar to the piece cut out but of shorter effective length.

For instance the method according to the invention may comprise cutting away a portion of the edge where the corner is to be, then bending the sheet to form the corner leaving a gap in the edge, and finally securing in the gap a gusset similar to the piece cut out but of shorter effective length.

The piece cut out may be of such depth as to leave the material of the shoulder so that the bending of the corner forms a surface of double curvature at the corner of the shoulder. Alternatively the piece cut out may be of less depth than the offset edge.

In one form of the invention the offset edge comprises two layers whereof one extends into the gap beyond the other, and the gusset also comprises two layers whereof one extends beyond the other, the gusset being secured in position by placing the layers which extend further flat against one another and securing them together as by welding. The second layer of the offset edge may be afforded by a strengthening strip secured to one face of the first layer, as by welding. Alternatively it may be formed as a continuation of the first layer which is folded over.

The invention also covers a sheet metal article, for example a generally box-like sheet metal casing, having one or more corners formed by the method referred to.

The invention may be carried into practice in various ways but one specific embodiment Way of example with reference to the accompanying drawings, in which,

Figure l is a rear perspective view of a washing machine embodying the invention,

Figure 2 is an enlarged perspective view of a corner of the casing before the gusset is inserted in the gap,

Figure 3 is a perspective view of the gusset seen from inside before being inserted, and

Figures 4 and 5 are sections respectively on the lines lV-TV and VV of Figure 2.

in the embodiment to be described the invention is applied to the outer casing C of a washing machine of which the front, two sides and outer portions of the rear wall are formed from a single piece of sheet metal C the rear wall being completed by a flat removable panel C The machine incorporates an inner container D for washing liquid and a wringer A mounted to fold down into it.

will be described by "ice The upper edge S of the metal wall C is to be inwardly offset to afford a shoulder S so that a flanged lid G may fit over the offset portion after the latter has been covered by a bumper strip T of rubber or the like, and the edge of the lid will be approximately flush with the remainder of the wall of the casing.

Difiiculty is liable to be experienced in bending the corners of such a casing since although the material of the shoulder can be longitudinally compressed so as to form a surface of double curvature the offset edge portion, especially if it is folded so as to be of double thickness, offers too great resistance to longitudinal compression and a satisfactory bend cannot be obtained without wrinkling.

Hence in accordance with the invention the offset edge is first formed in a bending machine whilst the sheet remains otherwise in the flat condition.

The offset edge portion is then cut away to form a rectangular notch 5 adjacent the position where each corner will be formed. If necessary the depth of the notch S may be equal to that of the offset edge S so that it extends right down to the shoulder S as shown, but under certain conditions it will be possible to obtain satisfactory results with a notch of lesser depth.

The sheet is then bent about what will be vertical axes to form the four corners which may be curved to a suitable radius. The material of the shoulder (and what if any is left of the offset edge below thenotch) is compressed longitudinally during this operation so as to produce a surface of a double curvature, and at the same time it will be appreciated that the opposed ends of the offset edges are brought closer together at each corner.

A strengthening strip U is then spot welded against the outer face of each side along the offset edge S, the strips being of such length as to terminate short of the vertical notches S Finally each corner is filled in by a gusset V comprising a small piece of metal of generally squat-T shape such that the stem V of the T, which will constitute the inner layer, is narrower than the head V which will constitute the outer layer. This is folded over and is then bent to a suitable radius to form the corner of the offset edge as shown in Figure 3 and is applied to the notch S so that the portion V fills that notch whilst the portion V abuts against the adjacent ends of the strengthening strips U and fills the space between them. The length of the portion V is slightly shorter than the original length of the notch S so that it fits in the gap when it has been shortened as referred to. The portion V is then secured to the offset edge S of the main blank by spot welding.

The casing may then be finished in known manner and the upper offset edge covered by the rubber bumper strip T.

It Will be appreciated that the invention is not limited to the details of the arrangement described by way of example. Thus instead of employing separate strengthening strips U welded in position it is possible to make them integral with the upper edge 8 of the side wall and fold them over similarly to the gusset V. Again the notch S may be cut out after the formation of the shoulder S or at the same time.

What we claim as out invention and desire to secure by Letters Patent is:

l. A method of forming an offset corner in a sheet of metal which comprises: working the sheet to form a shoulder and an offset edge extending therefrom substantially parallel to the plane of said sheet, removing a portion of said offset edge to form offset edge portions with a gap therebetween, working the metal to form a corner in said shoulder at said gap and position the separated offset edge portions substantially normal to each other, and closing said gap by a gusset to form a continuation of the offset edge portions around said corner.

2. A method according to claim 1 wherein the piece of tttwitMWM W 3 metal cut out to form the gap is of less depth than the depth of said offset edge.

3. A method according to claim 1, and placing metal alongside said olfset edge portions to form a second layer of metal with one layer extending into said gap beyond the other, and placing metal alongside said gusset to form a second layer of metal with one layer extending beyond the other, and closing said gap with said gusset by superimposing the said extended layers and securing them together.

4. A method according to claim 3, in which said second layer of said offset edge portions is formed by folding the latter to provide two layers of metal.

5. A method of forming an offset corner in a sheet of metal which comprises: removing a portion of said sheet along one edge thereof where the offset corner is to be made, working said sheet along said one edge to form a shoulder terminating in an offset edge generally parallel to and oflfset from the plane of said sheet and interrupted by a gap where said portion of said sheet was removed, bending said sheet to form a corner in said shoulder at said gap and form said olfset edge in two portions substantially normal to each other, and closing said gap by a gusset to form a continuation of said offset edge portions around said corner.

6. A box-like casing comprising: a single sheet of metal having a pair of opposite parallel side walls, an intervening wall substantially perpendicular to said opposite walls, and at least the edges of a fourth Wall substantially parallel to said intermediate wall, each of said walls having an integral shoulder projecting inwardly of the casing and said shoulders connected by integral corners, each of said shoulders terminating in an integral offset edge substantially parallel to its connected wall, each ofiset edge separated from adjacent ofiset edges by a gap at each of said shoulder corners, and metal gussets closing each of said gaps and secured to said ofiset edges at said corners.

7. A sheet metal article comprising: a single sheet of metal having a pair of angularly related Walls, each of said Walls having an integral shoulder connected together by an integral corner, each of said shoulders terminating in an integral offset edge substantially parallel to its connected wall, said offset edges separated by a gap in said single sheet at said shoulder corner, and a metal gusset closing said gap and secured to said ofiset edges at said corner.

References Cited in the file of this patent UNITED STATES PATENTS 1,462,467 White July 17, 1923 1,929,742 Hedlund Oct. 10, 1933 1,974,794 Blickman Sept. 25, 1934 2,095,964 Blickman Oct. 19, 1937 2,356,457 Gonda Aug. 22, 1944 2,357,793 Clark Sept. 12, 1944 2,455,828 Theil Dec. 7, 1948 2,675,774 Bergan Apr. 20, 1954 FOREIGN PATENTS 354,624 France Oct. 9, 1905 226,971 Switzerland Aug. 2, 1943

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