EP1872880A1 - Method and device for embossing a drum cover - Google Patents

Abstract

The procedure for introducing an embossing structure (3) into a metallic drum casing (1) of a washing drum, comprises positioning the drum casing, operationally locking the drum casing, and embossing the drum casing. The embossing pressure producing the embossing structure in the drum casing is exercised between the embossing structure consisting of a pressure drive and a supporting element. The supporting element is provided at a bearing surface with a die consisting of the counter structure. The cylindrically curved drum casing is held in a fixed position during the embossing process. The procedure for introducing an embossing structure (3) into a metallic drum casing (1) of a washing drum, comprises positioning the drum casing, operationally locking the drum casing, and embossing the drum casing. The embossing pressure producing the embossing structure in the drum casing is exercised between the embossing structure consisting of a pressure drive and a supporting element. The supporting element is provided at a bearing surface with a die consisting of the counter structure. The cylindrically curved drum casing is held in a fixed position during the embossing process. The drum casing is brought by turning and/or axially shifting into the intended embossing positions. The pressure forces exercised in the embossing on the drum casing mutually repeal themselves in the sum. Different embossing structures are produced in controlled manner. The drum casing is positioned over recesses, which has a typical function for the drum casing. The pressures produced for locking and embossing on one side from inner or outer radially aligned are on the drum casing. An independent claim is included for a device for introducing an embossing structure into a metallic drum casing of a washing drum.

Description

The invention relates to a method for introducing an embossed structure into a metallic hollow cylinder, in particular in the drum shell of a laundry drum, wherein the embossed structure is generated in segments between carriers on the drum shell and the embossing pressure exerted on the drum shell between at least one embossed structure having the pressure component and at least one support element acts as a pressure-transmitting components, which is coated on the contact surface with an elastic material or provided with a die having the counter-structure, and an apparatus for implementing the method. Hereinafter, without excluding the application of the invention to other areas, reference is made only to laundry drums.

Laundry drums of the type in question are provided in the drum shell with a plurality of holes that serve the liquid exchange during the washing or drying process. To optimize the washing process, symmetrically distributed drivers are arranged on the inner wall of the drum shell, via which a mechanism is introduced into the laundry during the rotational movement of the drum.

Very often, such laundry drums are provided between the receptacles for the driver with imprints that are shaped differently for the purpose of greater mechanical strength of the drum and / or to achieve a special washing technology target position of the manufacturers.

To introduce such embossments in the drum shell of laundry drums, methods and devices have been developed in which the desired embossments are introduced into a flat sheet metal blank and then the embossed metal sheet is rolled to form a drum shell cylinder. These methods have disadvantages, the use of the method is limited. The embossments introduced in the plane are partially changed during the subsequent bending process, specifically in the tangential direction more strongly than in the axial direction. Especially with deep embossing, for example, to increase the dimensional stability in the drum cylinder are introduced, this method is not applicable. The possibilities for introducing circumferentially extending embossed structures are also severely limited.

In order to avoid these deficiencies, improved processes have been developed in which embossments are introduced into the drum shell rolled into a cylinder. In the DE 199 54 027 C2 a method of this kind is described. In the known method, the drum cylinder, which has been rolled into a hollow cylinder in an upstream production step, is subjected to the embossing pressure in a rotary motion and guided between a pressure roller with a flexible jacket and a roller provided with support elements. Due to the different rotational speeds between the rollers and the drum wobbling can occur, which affect the uniformity of introduced over the drum periphery embossing structure.

This disadvantage avoids a in the DE 100 21 456 C2 described method in which the support elements are pressed from the inside of the drum shell and are rotated during the rotational movement of the pressure rollers with the drum in rotation. The supporting elements are carriers of the arch structure to be impressed. According to the intended number of drivers three or four support elements and corresponding pressure rollers are arranged distributed symmetrically in the device.

The method described above has the common disadvantage that the devices operating according to these methods are structurally complicated and very expensive to produce. In order to be able to ensure a uniform over the drum shell embossed structure, very high demands bgl. The accuracy of drum guide and positioning to make. The size of the rollers is to be matched exactly to that of the drum, which disadvantageously means that a corresponding roller must be used for each drum size. The same applies to different embossing structures. For manufacturers with a large range of equipment, this means having to hold a correspondingly large number of different rollers. Another disadvantage is that even with little wear of the rollers, the embossed structure can no longer be produced with the required accuracy and quality.

The invention has for its object to provide a method for producing the embossing in a drum shell that can be realized with simpler means. It is It is also an object of the invention to provide a method and a device realizing the method, which can be used for differently sized drums.

According to the invention this object is achieved by a method according to the features of claim 1 and with a device for implementing the method according to the features of claim 8. Further features and advantageous embodiments are contained in the respective subsequent subclaims, whose features can be used individually or in any combination with each other or with the features of claim 1 and 8 respectively.

Essential to the invention is that the cylindrically curved drum shell is held in a fixed position during the embossing process. The pressure-generating active components in the embossing device, which act on the drum casing from inside and / or outside, are linearly movable. The positionally safe holding the drum in the working position and the pressure applied to introduce the embossing pressure forces are directed radially from the outside to the middle of the drum and from the middle of the drum ago radially outwards and cancel each other out in the sum.

The device operating according to the method of the invention contains no rotating components which act on the drum. It eliminates rotary actuators and a complex leadership of the drum during the rotary motion. The device according to the invention is much simpler in comparison to those of the prior art and works extremely reliable. Furthermore, it is advantageous that the reproducibility and the accuracy of the embossed structures introduced can be improved and the tools wear out less.

As positioning aids for the establishment of the drum shell serve e.g. the boreholes, which are provided for fastening the drivers on the drum inner wall or other recesses, which have a typical function for the drum shell. This eliminates the burden of additional positioning aids.

In an embodiment of the method according to the invention, the embossments are introduced in several successive steps in the drum shell. In the various working positions of the drum-hollow cylinder is brought by rotation and displacement in the axial direction (parallel to the hollow cylinder axis). The device has to means by which the drum or drum can be moved together with the holding elements accordingly.

The additional time required for the embossing process in several work steps is compensated by the advantages that result from the use of smaller embossing dies. In addition to a more cost-effective production is also advantageous that in the circumferential direction narrower dies need not be adapted exactly to the radius of curvature of the drum. The permissible tolerance, at which no significant losses in the quality of the embossing occur, is greater the narrower the dies are designed in the circumferential direction. With very narrow embossing punches, without changing them, embossments can be made in drum coats with different radii. It must not be maintained as customary tools for each drum size, as is the case with known methods. The costs for tools and the changeover times for setting the embossing device to different types of drums are reduced. Another advantage is that the wear of the tools is very low; the service life of the tools is extended.

Narrow punches counteract the disadvantage that - as is unavoidable with wide punches - the imprints are not ideally radially introduced at the edges of the stamper and this leads to distortions that lead to quality losses especially in deep embossing or thick sheet metal material.

In an embodiment of the invention a plurality of narrower, the radius of the drum adapted stamp circumferentially arranged immediately adjacent to each embossing area. With such an arrangement, deep imprints of very high quality can be carried out in one work step.

In a further developed embodiment of the invention, the active components with respect to the time sequence, the pressure force and the stroke are controllable. In a correspondingly designed device, the linearly movable pressure elements acting from the outside on the drum shell are first actuated one after the other and activated with a low pressure force in order to lock the drum casing on a fixed holding cylinder. Subsequently, the printing elements, applied to the pressing force required for embossing, simultaneously and uniformly operated. This can be used to secure holding in the working position and the necessary for embossing the drum shell compressive forces be generated over the same component. The number of pressure generating components is thus significantly reduced, the embossing device is structurally much easier.

With such a device imprints can be introduced into the drum shell before it is welded at the seam or permanently connected in another way. From this special process variant, there are scope to design the technological process for the production of laundry drums in various ways.

In a further embodiment of the invention is provided to produce different embossing structures with a tool. For this purpose, the embossing die is segmented executed with in a curved surface next to and behind one another arranged stamp segments. In a simply configured embodiment, the individual punch segments are radially adjustable and can be fixed in at least two positions.

In a further solution variant, the individual punch segments are controllable with respect to the pressure depth and / or the pressure force exerted on them. With this very convenient embodiment a wide variety of embossments can be produced with a tool, without the embossing device must be retrofitted when changing the drum type. The use of the same tools for different embossing structures causes a considerable rationalization effect.

Fig. 1

Waschmaschine,

Fig. 2

Prägestruktur,

Fig. 3

Prozessablauf,

Fig. 4

Prägevorrichtung, 1. Variante,

Fig. 5

Prägevorrichtung, 2. Variante,

Fig. 6

Prägevorrichtung, 3. Variante,

Fig. 7

Prägestempel, segmentiert,

Fig. 8

Prägestempel steuerbar,

Fig. 9

Prägevorrichtung, Schnittebene durch die Trommelmitte, und

Fig. 10

Prägevorrichtung, Detail.

The method according to the invention and exemplary embodiments of the devices realizing the method are explained in more detail below with reference to the drawings. Show it

Fig. 1

Washing machine,

Fig. 2

Embossed structure,

Fig. 3

Process flow,

Fig. 4

Embossing device, 1st variant,

Fig. 5

Embossing device, 2nd variant,

Fig. 6

Embossing device, 3rd variant,

Fig. 7

Embossing stamp, segmented,

Fig. 8

Stamping controllable,

Fig. 9

Embossing device, cutting plane through the drum center, and

Fig. 10

Embossing device, detail.

In Fig. 1, a washing machine 15 is shown with a horizontally arranged laundry drum. The drum casing 1 has an embossed structure 3 in the areas between the drivers 16 (FIG. 2). The drum shell 1 is embossed according to a method in which the cylindrically curved drum shell 1 is held in a fixed position during the embossing process. The embossing is introduced in one or more work steps (see Fig. 3).

A first embodiment of an embossing device 7 is shown in Fig. 4, which is designed for laundry drums with three drivers 16. Characteristic of this device 7 are mutually symmetrically offset by 120 ° radially arranged embossing dies 4, which act from the outside perpendicular to the drum shell 1 and are covered with an elastic layer 5. An analog embossing device 7 for four drivers 16 is shown in Fig. 9 in longitudinal section.

The intended for receiving the drum shell 1 holder 2 is formed segmented. The outer surfaces of the retaining segments 2 have the embossed structure 3 as depressions and form the abutment to the externally acting embossing stamps 4. The individual retaining segments 2 are radially outwardly movable and are. With respect to their size and shape corresponding to the embossing dies 4 formed.

The plugged with little play drum shell 1 is taut and reliable held in the respective embossing position by spreading the retaining segments 2 radially outwardly against the inner wall of the drum shell 1. The spreading of the retaining segments 2 can be effected in a simple manner via an eccentric shaft. The eccentric shaft and other structural details of the embossing device 7 are not shown in the drawing.

The embossing device 7 described can be used for closed drum shells 1, which are welded at the seam or firmly connected in another way. With the device 7 drum shells 1 can be processed without and with inserted rear wall. Associated with this is the advantage of being able to flexibly place the embossing process in the technological production chain of the laundry drum. The pressurization of the three punches 4 takes place simultaneously and under the same pressure, so that the applied pressure forces cancel each other out in the sum. The requirements for the housing of the device 7 with respect to its mechanical strength can be kept to a minimum.

The device is designed so that the embossing process takes place in two steps. After a first embossing process, the retaining segments 2 are released, the drum shell 1 is rotated by a little less than 60 ° and firmly clamped again in the second printing position. The embossing device 7 can also be designed for more than two working steps, wherein the different positions can be adjusted both by turning and by moving the drum shell 1 in an axial direction to him. The various working positions can also be adjusted by rotating and / or displacing the holding device 2 together with the clamped drum shell 1 in the embossing device 7.

In a simple version with two working positions in the axial and tangential direction, the holding devices 2 are driven against rigid stops (not shown) which determine the respective end positions. The control of such a device can be realized in a very simple manner.

In another embodiment (Fig. 5), the embossing device 7 is designed for laundry drums 1 with four drivers. The four punches 4 are arranged symmetrically offset by 90 ° in the embossing device 7 and completely cover the individual embossed areas between the Mitnehmern16. For safe positioning positioned holding the drum shell 1, a rigid cylinder 17 is present, the radius of which is adapted to the drum shell 1.

The device is specially designed so that the cylindrical rolled drum shell 1 is not yet welded at the seam or permanently connected in any other way. The cylindrical carrier 17 contains no active components. The externally acting radially on the drum shell 1 plunger 4 form in functional unit at the same time the holding and the embossing elements. This simplifies the construction of the embossing device 7 considerably. An embossing device 7 constructed in this way can be produced inexpensively and is easy to operate.

The drum shell 1 is pushed approximately horizontally onto the solid cylinder 17, which is provided with an elastic layer 5 circumferentially and positioned with the aid of the boreholes provided for the fastening of the driver and then fixed by means of the pressure stamp 4 engaging from the outside and movable in the radial direction. Due to the open seam, the cylindrical rolled drum shell 1 can be easily attached to the holding cylinder 17. The plunger 4 are actuated sequentially in time, the two of the open drum seam 10 opposite punch 4 are first brought into attack. This ensures that the drum shell 1 rests closely over the entire surface of the support cylinder 17. After clamping, the embossed structure 3 is introduced, wherein the required pressure 11 is applied simultaneously and uniformly over all pressure punches 4, as in the first example. In the drawing, the time sequence and the pressure strength of holding and embossing pressure 13 and 11 are represented symbolically by different strong and arranged behind each other arrows.

In the embossing device 7 in FIG. 6, a plurality of embossing dies 4 aligned with the drum axis are arranged directly next to one another per embossing area. The pressure surfaces are adapted to the drum radius. Each individual stamp 4 is radially movable. The device 7 is particularly suitable for introducing deep embossing structures 3. The more embossing dies 4 are arranged circumferentially, i. the narrower the tangential width of the punch 4 is designed, the better quality requirements can be realized and the lower the wear of the tools.

In Fig. 7 and 8, two segmented embossing units are shown. The embossing unit consists of a curved support 8 with a plurality of radially aligned guides 9 for receiving individual, linearly movable punch segments 6. The punch segments 6 are in an active, the embossed structure 3 generating position can be fixed (Fig. 7). The embossing pressure 11 is generated by radial movement of the carrier 8.

In the embossing unit 8 in Fig. 8, the punch segments 6 are individually controllable with respect to the pressing force and the embossing depth. The carrier 8 is not in the embossing process emotional. With such an embossing unit different embossed structures 3 can be generated controlled.

The application of the segmented embossing units results in the possibility of embossing drum shells 1 having different structures with only one tool.

Claims (17)

Method for introducing an embossed structure (3) into a metallic hollow cylinder, in particular in the drum shell (1) of a laundry drum, wherein the embossed structure is produced in segments between drivers (16) on the drum shell (1) and the embossing pressure exerted on the drum shell (1) between at least one pressure component (4) having the embossed structure and at least one support element (2) acting as pressure transmitting components coated on the abutment surface with an elastic material (5) or provided with a matrix having the counterstructure, characterized in that cylindrically curved drum shell (1) is held in a fixed position during the embossing process. A method according to claim 1, characterized in that the drum shell (1) is processed one after the other as follows: - Positioning, - reliable locking - Shape. A method according to claim 1, characterized in that the embossments (3) in several steps in the drum shell (1) are introduced, wherein the drum shell (1) by turning and / or by axial displacement (parallel to the hollow cylinder axis) successively in the intended embossing positions is brought. A method according to claim 1, characterized in that the embossing on the drum shell (1) exerted pressure forces (11, 13) cancel each other out in the sum. A method according to claim 1, characterized in that different embossed structures (3) are generated controlled. Method according to Claim 1, characterized in that the pressures (11, 13) generated for the reliable locking and embossing are aligned radially on the drum shell (1) from the inside or outside on one side. A method according to claim 1, characterized in that the drum shell (1) is positioned over recesses which have a typical for the drum shell (1) function. Device for introducing embossed structures into a metallic hollow cylinder, in particular into the drum shell (1) of a laundry drum according to the method according to one of Claims 1 to 7, with pressure-generating components (2) acting from inside and / or outside on the drum shell (1) , 4), characterized in that at least one of the embossing structure (3) generating components (2, 4) is active and in the embossing device (7) is linearly movable and that for reliable locking of the drum shell (1) and / or the when embossing transmitted compressive forces (11, 13) are directed radially towards the hollow cylinder axis and away from it. Apparatus according to claim 8, characterized in that the active components (2, 4) in the embossing device (7) are arranged rotationally symmetrical to each other. Apparatus according to claim 8, characterized in that the contact surfaces of the active components (2, 4) are adapted to the radius of the drum (1). Apparatus according to claim 8, characterized in that the contact surface of a group of active components (2 or 4) occupied by the embossing structure to be introduced (3) and the contact surface of the group of counteractive active components (4 or 2) with an elastic material (5 ) is provided. Apparatus according to claim 8, characterized in that the contact surface of a group of active components (2 or 4) occupied by the embossing structure to be introduced (3) and the contact surface of the group of counteracting active component (4 or 2) with the Gegenmatrize (14) is provided. Apparatus according to claim 8, characterized in that per embossing area a plurality of radially aligned dies (4) are arranged directly next to each other. Apparatus according to claim 8, characterized in that the embossing (11) generating components in guides (9) of a carrier (8) for a plurality of in a cylindrical surface next to and behind the other arranged punch segments (6) guided radially movable, with respect to the embossing depth and / or the pressure force can be controlled and fixed in at least two positions. Apparatus according to claim 8, characterized in that the embossing (11) generating components guided in guides (9) of a carrier (8) for a plurality of in a cylindrical surface next to and behind one another arranged punch segments (6) radially movable and with respect to the embossing depth and / or the pressure force are controllable. Apparatus according to claim 8, characterized in that the receptacle for reliable locking of the drum shell (1) is a rigid cylinder (17), which is preferably covered over the entire surface with an elastic material (5), and that the punch (4) for generating the Holding and the embossing pressure (13, 11) are used and from the outside on the drum shell (1) are arranged to be moved. Apparatus according to claim 8, characterized in that the rigid cylinder (17) or the holding elements (2) in the embossing device (7) are arranged parallel to the hollow cylinder axis displaceable and / or rotatable or pivotable about it.

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