CA1108937A - Methods of forming inwardly flanged curved members and/or inwardly flanged curved members - Google Patents

Abstract

ABSTRACT

Curved inwardly flanged members in the form of cylinders (1) or conical frusta have the flange (2) thereof formed by folding sheet material (24) about a plurality of fold lines (3,10) to form corrugations or castellations having sides (6) of triangular formation and diverging first frusta segments (11) and second frusta segments (4,16) lying on two diverging conical frusta of short height relative to diameter. Such cylinders and frusta have hubs (25,58) and comprise rotating drums suitable for laundry machines such as clothes washing machines and clothes driers.

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Description

This inven-tlon rela-tes -to me-thods of forming inwardly flanyed curved members and/or inwardly flanyed curved members and has been devised particularl~ thouyh not solely in relation to forming inwardly flanged c~linders or conical frusta as par-ts of drums for clothes washing machines or driers.
It is an object of the present invention -to provide a method of forming inwardly Elanged curved members and/or inwardly flanged curved memhers which will at least provide -the public with a useful choice.

Accordingly in one aspect the invention consists in a method of forming an inwardly flanged curved member from sheet material comprising the ste~s of folding part Oe -the sheet material to form the flange about a plurality of successive substan-tially radial fold lines so that the peripheral length of any circumference of the flange at a constant radius from the centre of curvature of the curved member is substantially constant.

- In a further aspect the invention consists in a method - of forming an inwardly flanged cylinder or conical frustum said method comprising the steps of forming a flange on at least one edge of a sheet of material in a manner such that the finished article has a wall in the form of a cylinder or conical frustum with the flange in a plane substantially at right angles to the walls of the cylinder or frustum the flange having corrugations or castellations such that -the material of the flange is fol(led on old lines so -that li-ttle or no stretching or compression o~ such ma-terial occurs.

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-~ ' In a still fur-ther aspect the invention consists in an inwardly flanged curved member formed from sheet material and having an inwardly directed flange on at least one end thereof said flange having triangular webs alternating with frusta segments, the alternate frustum segments lying on two different frusta diverging from the flange curved member with the apices of the triangular webs lying on a fold line common to the parent curved member and said frustum segmen-ts.
In .a still ~urther aspect the invention consists in an inwardly flanged curved member formed from sheet ; material into a cylinder or frustum of a cone having an .inwardly directed flange on at least one end -thereof said flange being formed by a series of fold lines with sub-stantially triangular webs be-tween first and second fold . - - lines in one set of adjacent fold lines and adjacent sets of fold lines being separated by a short distance to form frustum segments lying in two different frusta, the apices of said triangular webs lying on a further fold line common 2Q to t.he parent wall and said first fold lines lying on one frustum and said second ~old~lines lying on a second frustum the outer edges of said two different frusta being separated by the bases of said triangular webs.
In a still ~urther aspect the invention consists in an inwardly.flanged curved me~ber formed from sheet material into.a cylinder or frustul~ of a cone haviny an lnwardl.y directed flange on at least one end thereo:e, said elange being formed into a series of corrugations or castellations with two adjacent cas-tellations one having a frustum segment - ' ' .

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forming a bot-tom surface, the o-ther a frustum segment forming a top surface and the bottom and top surface being separated by a side sur-Eace, the s:ide surface being connected to the bottom and top surfaces by fold lines which diverge from each other as the distance from the parent cylinder or frustum of a,cone increases.
In a still further aspect the invention consists in a rotatable member comprising the combination of a flanged curved member in the form of a cylind,er or a frustum according to any one of the preceding paragraphs and a , hub fixed to said flange by fixing means which engage at, least some of said frus-tum segments of each oE said two different frusta.' - In a still further aspect the invention consists in a laundry appliance such as a clothes washing machine and a clothes drier having a drum including a rotatable member according to the preceding paragraph.
To those skilled in the art to which this invention , relates, many changes in construction and widely differing 2~ embodiments and applications of the invention will suggest ; ' themselves without departing from the scope of the invention as defined in ~he appended claims. The disclosures' and the description herein are pureIy illustrative and are not intended to be in any sense limiting.
~ One preferred form of the invention will now be described with reference to the accompanying drawings in which:--' ' , '' ~' ~ ', .

~3~37 Fig. ] is a plan view of an inwardly flanged curved member according to the invention, Fig. 2 is a cross-section of the construc-tion shown in Fig. 1, Fig. 3 is a perspective view of a ~lo-thes washing drum incorporating the flanged cylinder of Figs. 1 and 2, Fig. 4 is a perspective sketch of a lower part of the dr~ of Fig. 3, Fig. 5 is a plan view of the drum of Fig. 4, Fig. 6 is a cross-section of the drum oE Figs. 4 and 5 including a hub within it but removed from engagemen-t with the flange, Fig. 7 is a sketch o~ a sheet partly formed into a cylinder and flange according to the inven-tion, Fig. ~ is a cross-sectional elevation o a clothes washing machine incorporating a drum or tub according to the invention, and Fig. 9 is a sketch of a clothes drying drum according to the invention.
Referring to Figs. 1 to 3 of the drawings a curved member in the form of a cylinder 1 is formed having an inwardly directed flange 2 from a sheet of material such as a sheet of stainless steel. The forming of the flange 2 is effected by folding part of the sheet material ~the flange material) about foid lines so that little or no stretching or compression of the material results as follows.
Commencing with the radial eold line 3 a lower po~tion of the material of the flange reeerenced ~ as a result o e the folding is turned in the plane substantially at right angles to that of the sheet material forming the wall 5 of .
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" ' . ' '': ' : ,, . ' ' , ~ , ' the cylinder. An adjacent surface 6 is turned at right angles -to the firs-t surface 4. The fold llne 3 is arranged to Iie on a radjus from a centre 7. A next fold line lO
is between the surface 6 and a second sur~ace ll, the second surface ll being substantially parallel to -the surface but displaced therefrom. As may be seen in Fig. 3 the surface 6 is of triangular formation tapering from a base length 12 as seen in Fiy. 2 to a minimum length (practically zero) adjacent the junction 13 between the cylinder and the flange. ~ further triangular sur:face 14 is provided between the fold line 15 and a fold line between surface l~ and ~-surface 16, the surface 16 being in the same plane as surface 4 and this pattern is continued around the periphery ' of the :Elange until the whole of the flange has been formed. The ends 17 (Fig. 31 of the cylinder 5 are then joined together by lock seaming, spot welding or otherwise as desired. The ends of the flange material need not be joined since bolting to a hub will effectively lock the , ' flange ends in position,'particularly if the ends are over-lapped an~d bolt holes made near each end through which a hub bolt is inserted and fastened. A hub 18 is then fitted to appropriate ones of the surfaces 4 and ll formed by the above fold lines being fi-xed by welding or stainless iron ., fasteners such. as rivets or bolts and nuts, parts of which ' pass through the apertures l9 and through corresponding apertures in the hub l8 and par-ts of which such a.s the heads of the bolts and the nuts ho],d the surfaces ~ ancl ll to -the hub 18.
It will be seen that the flangi.ng is ~ormed by bending .
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the flange material about fo]d lines Eirst in one direction then in that same direction, then in the opposite direction and then again in the latter direction. The foldiny has the result that the peripheral length of any circumference of the flange is substantially constant and this peripheral length is in the form of corruga~ions or castellations 60.
Preferably the transitions between cylindrical and conical parts have substantial radii, e.g. 40-50 mrn. l'his may be effected ei-ther by providing a twisting action between members which hold the material on ei-ther side of a fold line in a manner such that each fold line is formed sub-stantially independently of any other fold line or alter-nativeIy a series of ~old lines are ormed substantially simultaneously. The folding may be ef~ected either by an indlvidual tool having two members with a gap therebetween - two such tools being side by side and turned relative to each other in the required direction or by a single tool, the rigidity of the material supplying the reaction force against the turniny of the single tool or by a series, for example, a pair of interengaging wheels having two forms corresponain~ to the shape o~ the ribs 22 or by an operation in which the ~langed material is pressed by one former over another shaped former to give the deslred result.
~ The above construction refers to a cylinder having a sharp bènd or square corner between the cylinder and the - flange. In E'igs. 4 and 5 -there is shown a part cylinder and flange arrangement in which there is a curvcd portion 20 between the cylindrical wall 21 and the flange generally shown at Z2. However, the ~lange is ~ormed in the same way ,' ' ' ' ' .

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3~3 as above described and the same reference numbers havé
been used in Fig. 4. In Fig. 5 it can be seen that the radial lines 3 extend from the inner edge 23 of the castellations o.r corrugations made according to -the invention.
In ~ig. 6 the cylinder and flange of Figs. 4 and 5 is shown in cross-secti.on and inside the cyl.inder is a hub 25 having castellations 26 which in use engage the castellations of the flange 27. It will be seen that the surface 28 of the hub 25 may be fixed to the surface 11 of the flange and -the surface 29 fixecl to the surface 16.
Thus, the hub is fixed to the flange in two planes giving considerable increase in strength as compared with existing constructions which use only a single plane of fixing. The hub may be made of any suitable material, for - example, may be a die casting.
- ~ In Fig. 7 there is shown a blank 24 in which the castellations are formed in a part thereof and the blank 24 thus has a portion which has been curved by a suitable : 20 operation before the castellating operation is commenced.
` .Referring now to Fig. 8 ~that figure shows a laundry appliance 30 in the form of a clothes washing machine in cross-section containing an electric motor 31, a drive mechanism 32 driving an agitator 33 through a shaft 34 and having a tube 35 which drives a hub 36 on which is mounted the drum or tub 20~ Ayain the ~lange (2) of the drum 20 is . fastened to the hub 36 in two planes b~ screws 37 and 38 again giving the desired e:Efect.
: - It is to be noted tha~ the drum 20 is provided w~-th `~ ' ' ~ ' ' 8~37 apertures, Eor example, apertures 40 comprisiny pieces of metal which are cracked out from -the parent metal to leave a gap between the expanded piece of metal and tlne parent metal while the expanded piece Oe metal is stil~ retained by the members 41 and 42 to the paren-t metal 43.
Thus, the openings are provided in the cylinder by making -two parallel cu-ts and stretching -the metal between the cuts so that a loop is :Eormed, the ends o~ the loop being still integral with the parent metal so that the lO openings are provided between the edges of each stretched piece of metal and the parent metal.
The dr~n 50 shown in Fig. g is, for example, a rotat-able member for use as a drum of a clothes drying machine such as -that described in British Patent Specifica-tion No. 1,221,343. The flange 51 formed as above described is fixed to flanges 52 and 53 which form a hub 58 by pop rivets, spot welding or bolts. It is to be noted that flange 52 is on tubular shaft 54 and flange 53 is on a collar 55 fixed to the shaft 54. It will be noted that the hub fixing to the flange is in two planes. The ~lange 55 also formed as above describe~ surrounds an opening 56 which is defined by a channel cross-section ring 57 of, for example, a suitable plastics material.
It will be seen that in at least one of the preferred forms the above construction results in the formation of a flanged cylinder or frustum of a cone (or for tha-t matter a cone) in which an inwardly d.irected :flange is eormed by folding metal rather than by stretch;.ng i.t as :is e:efected in a drawiny operation. The drawing operat.ion has the . _ 9 - .

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disadvantage that the metal of the drawn flange is thinned at points where it is desirable to have increased streng-th rather than reduced s-treng-th.
It will be seen also that the resulting flange is of considerable strength in that the surfaces 11 of the adjacent ribs lie on the surface of a conical frust~n having a low height relati-ve to its width and the surfaces

4 lle on a similar conical ~rustum but which is inverted relative to the frustum on which the surfaces 11 lie.
Again, this gives an increase in strength in a desirable manner! particularly when used to fix the drum to a hub as described.
The flanged cylinder made as above described is preferably provided as an outer or preferably inner container for a clothes washing machine, the inner container being lined with, for example, a liner of a plastics material.
The invention also enables inwardly flanged drums or tubs to be made of, or example, stainless steel withou-t the necessity for using e`xpensive deep drawing quality metal.
Again, because of the absence of the thinning which is normally present when deep dr~awing is necessary a thinner gauge metal may be used. Also, since folding and preferably consecutive folding operations are used, the power (and therefore size of the equipment) and energy requirements are less ~han with deep drawing, resulting in savings in running and capital costs.
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Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of forming a rotatable drum for a laundry machine comprising the steps of forming a rectangular shaped sheet of material to a cylinder, fixing the sides of the sheet to each other, integrally forming on at least one end of said cylinder, a radially inwardly directed flange and having a width substantially less than the length, of the cylindrical member, by forming said flange to have a castellated shape at its inner edge the flange thereby having triangular webs alternating with sets of segments, the sets of segments being spaced apart by said triangular webs and diverging from the outer edge of said flange at the cylindrical surface of said cylindrical member to said castellated shape at said inner edge of said flange.

2. A rotatable drum for a laundry machine comprising a cylindrical member formed from rectangular shaped sheet material with the sides thereof fixed to each other thereof, a radially inwardly directed flange integrally formed on at least one end of said cylindrical member and having a width substantially less than the length of the cylindrical member, and flange having a castellated shape at its inner edge by having triangular webs alternating with sets of segments, the sets of segments being spaced apart by said triangular webs and diverging from the outer edge of said flange at the cylindrical surface of said cylindrical member .

3. A rotatable drum for a laundry machine comprising a cylindrical member formed from sheet material and open at the ends, a radially inwardly directed flange integrally formed on

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at least one of said ends, said flange having a width substan-tially less than the length of the cylindrical member and having a corrugated cross sectional shape formed by a series of fold lines with substantially triangular webs between first and second fold lines in one set of adjacent fold lines and adjacent sets of fold lines being separated by a short distance to form two sets of segments separated from each other by said triangular webs.

4. A rotatable drum for a laundry machine comprising a cylindrical member formed from sheet material, said cylinder having open ends, a radially inwardly directed flange on at least one of said ends having a width substantially less than the length of the cylinder, said flange having a cross sectional shape of a series of corrugations adjacent pairs of corrugations providing one substantially planar segment forming a bottom sur-face and a second substantially planar segment forming a top surface, said bottom and top surfaces being separated by triangu-lar side surfaces, the side surfaces being connected to the bottom and top surfaces by fold lines which diverge from each other in the radially inward direction.

5. A rotatable drum for a laundry machine as claimed in claim 1 and further comprising a hub fixed to said flange by fixing means which engage at least some of each set of said segments.

6. A rotatable drum for a laundry machine as claimed in claim 2 and further comprising a hub fixed to said flange by fixing means which engage at least some of each set of said segments.

7. A rotatable drum for a laundry machine as claimed in claim 3 and further comprising a hub fixed to said flange by

Claim 7 continued .....

fixing means which engage at least some of each set o said segments.

8. A rotatable drum for a laundry machine as claimed in claim 5, 6 or 7 wherein the cylindrical surface of said cylindrical member is provided with a series of apertures therein, each aperture being formed by forming adjacent two parallel slits of equal length through said cylindrical surface, the strip of material between the slits being expanded radially outwardly to form a loop fixed at each end to said cylindrical surface.

9. A rotatable drum for a laundry machine as claimed in claim 5, 6 or 7 wherein there are two sets of segments, a first set forming a first surface and a second set forming a second surface.

10. A rotatable drum for a laundry machine as claimed in claim 4 and further comprising a hub fixed to said flange by fixing means which engage at least some of the segments forming the bottom surface and at least some of the segments forming the top surface.

11. A rotatable drum for a laundry machine is claimed in claim 10 wherein the cylindrical surface of said cylindrical member is provided with a series of apertures therein, each aperture being formed by forming adjacent two parallel slits of equal length through said cylindrical surface, the strip of material between the slits being expanded radially outwardly to form a loop fixed at each end to said surface.