Title of Invention	WASHING DRUM FOR A WASH TREATMENT MACHINE AND A TOOL FOR PRODUCING THE SAME
Abstract	This invention relates to a washing drum for a wash treatment machine, in which metal wall parts of the washing drum are provided with holes for entry of treatment mediums like water or air; the surrounding regions of the holes are drawn out in the direction of the outer side of the washing drum in the shape of a tulip or truncated cone, in which the hole edges are shaped flat.

Full Text

The invention pertains to a washing drum for a wash treatment machine, in which metal wall parts of the washing drum are provided with holes for the entry of treatment mediums like water or air; the surrounding regions of these holes are drawn out in the shape of a tulip or truncated cone in the direction of the outer side of the washing drum; and a tool made of a guided hole-cutting needle for producing such a drum, having a counterpoint provided with a cutting hole and resisting below the level of the inserted metal wall part. Such a washing drum is known from DE 1 756 317 U and from DE 66 06 902 U. In the production of the washing drum depicted in DE I 756 317 U apparently each flood hole is first punched out before its tulip is drawn out. This can be identified by the fact (DE 1 756 317 U, fig. 1 and 2) that the hole edges stand on the drum jacket at an inclination to the normal. On the other hand, in DE 66 06 902 U the shape of the flood holes of a washing machine-washing drum are depicted idealized. Such flood holes are still regularly produced today by a method as shown in fig. 1, in which the drum sheet metal 1 is first drawn in the punching tool 2 upto the counterpoint 4 by a downstroke cutting needle 3, before the hole section 5 is cut out. However, during cutting by the downstroke cutting needle 3, one gets a section which is at an inclination to the tulip-shaped drawn-in metal point of the drum metal 1, through which a burr is drawn at the lower edge 6 of the hole edge. This burr remains in the direction towards the outer side of the drum and spells danger on two counts: for one, the lower edges 6 are so sharp due to the burr that for washing machines which can be operated from the drum side and in case of manual rotation of the drum to the operating position, the fingertips of the operating person can get cut. The other danger is, that during spinning washing items glide through the flood holes at least to such an extent that single fibres could get caught on the burr and tear when the drum slows down and the wash items fall back into the drum. However, this simplified production method is supposed to be retained on principle. But it is the task of the invention, while following a simple production method according to fig. 1, to design a washing drum of the type already mentioned in such a way that the danger to the \ fingertips as well as the danger of the clothes fibres penetrating the flood holes and getting " hooked on to the outer edge of the holes get eliminated to a great extent. This task is fulfilled by the invention, in that the hole edges are shaped fiat. On fiat-shaped regions, whose hole edges are placed on a counter-point after punching out the holes, an already formed burr is set into the hole interior while drawing back the hole edge on the counterpoint and then slightly rounded upwards by the returning cutting needle. An especially advantageous design form of the invention was found, in that the peripheral regions have approximately twice the diameter of the holes. In this way, the truncated cone angle in the peripheral regions is large enough to, on the one hand, sufficiently escape from the reachability range of the wash-clothes; and, on the other hand, while drawing the surrounding regions the hole edge gets drawn back sufficiently enough in the tool. This purpose is also served by a further improved version of the washing drum, in which the flatly shaped hole edges have a width which is a fraction of the diameter of the holes. The required specifications of the washing drum as per the invention are also fulfilled in a very advantageous manner by a tool, in which the cutting needle for drawing a tulip or a truncated cone for a hole and for cutting out a hole section in a forming sleeve is designed/guided in such 2 a way that the cutting needle sits on the metal wall part before the forming sleeve and the stamping sleeve reveals an offset face whose diameter is lesser than the outer diameter of the surrounding regions of the holes. The invention is described in details below on the basis of a design example shown in the accompanying drawing. The following are shown: Fig.1 A flood hole of a washing machine-washing drum in the tool according to the state-of-art technology; Fig.2 A design form of a flood hole for a washing machine-washing drum as per the invention, also in a tool similar to the one in fig. 1; and Fig.3 An enlarged view of the detail III in fig.2. In the flat form of the hole edges 7 as per the invention, as shown in fig. 2 and 3, just like In the state-of-art technology a burr gets created on the outside edge 6. It is however rendered safe for clothes and fingertips on account of the special design of the tool. For this, in the upper part 8 of the tool a forming sleeve is additionally arranged, which sits on the drum metal 1 after the cutting needle 3. Initially the cutting needle 3 draws the hole edge 7 outwards in a conical shape till the metal sheet 1 sits on the counterpoint. Then the needle 3 cuts out the hole section 5, before the forming sleeve 9 dish-draws the hole edge 7 upto the counterpoint 4. Thereby the short meridian line of the truncated cone gets elongated because it is drawn deeper by the offset shape of the forming sleeve 9. Thus the edge 6 of the hole edge 7 retracts over a stretch T of about 0.1 to 0.2 mm from the cutting needle 3 and takes along its burr 11, which is drawn over the edge of the counterpoint 4 and hence sets itself hole-Inwards. As soon as the cutting needle again moves upwards, its outer face rubs along the burr 11 and draws it slightly upwards at the same time rounding it, i.e. in the direction on to the drum interior. It is thus completely removed from the accessibility range of the fingertips. The rounding - this has been the Finding - allows clothes fibres which have reached the burr 11 to slide away again, so that tearing of fibres is now almost ruled out. It can be seen that the holes have a diameter which is larger by an amount 2XT, than the cutting needles 3 of the tool that cut them. Fig 2 also shows outer portions 11 of the washing machine drum outside a sheet metal wall portion 1, as well as region 10 of the sheet metal wall portion 1 surrounding the holes toward the outer portions 11. The regions 10 surrounding the holes have flat-formed edges 12 bordering the holes. In Fig. 2 the holes have a diameter D, the flat-formed edges 12 of the sheet metal wall portion 1 bordering on the holes have a width B which is a fraction of the diameter 0, and the regions 10 of the sheet metal wail portion 1 surrounding the holes have a diameter approximately twice the diameter D of the holes. Therefore, the female stamping die 9 has an offset end surface with a diameter D+2xB which is less than the outer diameter D+2x"10" of the surrounding regions 10. In a washing machine-washing drum, the holes designed as per the invention are generally provided as flood holes in the jacket of the washing drum (not shown). They can also be additionally arranged in one or both bottom discs of the washing drum. On the other hand, for a washing drum of a clothes drier such holes can be arranged for example exclusively in one bottom disc, through which hot air is blown into the washing drum. WE CLAIM Washing drum for a wash treatment machine , in which metal wall parts of the washing drum are provided with holes for entry of treatment mediums like water or air; the surrounding regions of the holes are drawn out in the direction of the outer side of the washing drum in the shape of a tulip or truncated cone, in which the hole edges are shaped flat. 2. Washing drum as per claim 1, in which the surrounding rcgions(1O) havc L. twice the diameter of the holes (D). " 3. Washing drum as per claim 1 or 2, in which the flatly shaped hole edges have a width(B) which is a fraction of the diameter (D) of the the holes. 4. Washing drum as per one of the claims 1 to 3, in which the holes have a diameter(D) larger than that of the cutting needles (3) of the tool by an amount (2 x T). 5. A tool made of a guided hole-cutting needle for producing such a drum, having a counter-point provided with a cutting hole and resisting below the level of the inserted metal wall part, as per one of the claims 1 to 4, in which the cutting needle(3) is designed for drawing a tulip or a truncated"cone for a hole and for cutting out a hole section in a forming sleeve in such a way that the cutting needle (3) sits on the metal wall part before the forming sleeve (9) and the forming sleeve reveals an offset face whose diameter (D + 2 x B) is lesser than the outer diameter (D + 2 x "10") of the surrounding regions (10) of the holes. This invention relates to a washing drum for a wash treatment machine, in which metal wall parts of the washing drum are provided with holes for entry of treatment mediums like water or air the surrounding regions of the holes are drawn out in the direction of the outer side of the washing drum in the shape of a tulio or truncated cone, in which the hole edges are shaped flat.

Documents:

02339-cal-1997-abstract.pdf

02339-cal-1997-claims.pdf

02339-cal-1997-correspondence.pdf

02339-cal-1997-description (complete).pdf

02339-cal-1997-drawings.pdf

02339-cal-1997-form 1.pdf

02339-cal-1997-form 2.pdf

02339-cal-1997-form 3.pdf

02339-cal-1997-form 5.pdf

02339-cal-1997-letter patent.pdf

02339-cal-1997-pa.pdf

02339-cal-1997-priority document others.pdf