EP3132868A1

EP3132868A1 - Tool for electromagnetic forming of containers with relief protrusion

Info

Publication number: EP3132868A1
Application number: EP15466009.6A
Authority: EP
Inventors: Jan Sedlacek; Josef Divoky
Original assignee: Moravia Cans AS
Current assignee: Moravia Cans AS
Priority date: 2015-08-17
Filing date: 2015-08-17
Publication date: 2017-02-22
Anticipated expiration: 2035-08-17
Also published as: HUE035796T2; EP3132868B1

Abstract

Tool (1) for electromagnetic forming of aerosol containers with relief protrusion which contains a support tube (10), a forming unit (26) seated firmly on the support tube (10), wherein the forming unit (26) consists of a hollow casing (5) with a movably arranged hollow cage (11) inside, wherein both the casing (5) and the cage (11) are provided on their walls with openings (18,19) which overlap themselves in an assembled state, further the forming unit (26) contains a pressure body (25) fixedly arranged in openings (19) of the casing (5), the pressure body (25) touches from above the forming segments (13) movably arranged in radial direction in openings (18) of the cage (11), wherein to the cage (11) is towards to the supporting tube (10) a tube guiding portion (21) adjoint, this tube guiding portion (21) is slidably arranged in the supporting tube (10), wherein between the supporting tube (10) and the cage (11) press springs (15) are mounted, the embossing tool (1) is further provided with cooperating stops for defined insertion of the container into the tool (1), wherein the casing (5) is on its free end provided with a cover (6) to prevent falling out of the cage (11) and inside of the embossing tool (1) a coil (30) for electromagnetic forming is arranged.

Description

Background of the invention

The invention relates to so-called embossing. It is a technique of decoration of materials. In the present invention embossing relates to the decorating of aerosol containers.

State of the art

Embossing is a known technique of decoration, when the surface of various metalic and non-metallic material is provided with embossed projection. If it is a flat object, e.g. credit cards, various press tools are used.
For this purpose, however, it is also possible to use the electromagnetic forming, which is long-known technology. It is based on the use of the repulsive effect of two repulsive magnetic fields, and that in the coil and in the formed material which is conductive. This creates a pressure effect of a strong magnetic field on conductive metals. By quick discharging of current in the coil, current of the opposite charge in the formed material is induced and thus also the opposite magnetic field. Forming energy can be set up and controlled. To the forming, only half of the tool is suficient, the other half consists of the coil.
In DE 10 2011 003 548 A1 a method of forming of shaped geometric projection onto a flat plate is presented, but it is stated that this technology does not apply only to flat plates.
It is also known that it is possible to create even more decorative relief types than just protrusions.
The aim of the invention is to present a tool for electromagnetic forming of containers with relief protrusion, which allows embossing of hollow objects along parts of the surface or even over the entire circumference.

Summary of the invention)

Deficiencies mentioned above are eliminated by the tool for electromagnetic forming of containers with relief protrusion according to the invention whose principles consist in that it contains a support tube, a forming unit seated firmly on the support tube, wherein the forming unit consists of a hollow casing with a movably arranged hollow cage inside, wherein both the casing and the cage are provided on their walls with openings which overlap themselves in an assembled state, further the forming unit contains a pressure body fixedly arranged in openings of the casing, the pressure body touches from above the forming segments movably arranged in radial direction in openings of the cage, wherein to the cage is towards to the supporting tube a tube guiding portion adjoint, this tube guiding portion is slidably arranged in the supporting tube, wherein between the supporting tube and the cage press springs are mounted, the embossing tool is further provided with cooperating stops for defined insertion of the container into the tool, wherein the casing is on its free end provided with a cover to prevent falling out of the cage and inside of the embossing tool a coil for electromagnetic forming is arranged.
In a preferred embodiment the pressure body is formed by a pressing insert with bearings arranged in the opening of the casing.
In another preferred embodiment have the forming segments an outer shaped surface with transverse rest grooves and inner forming surface.
In another preferred embodiment the stops are formed as a stop surface made on the end of the draw bar which is connected to the tube guiding portion and as a stop surface made on the holder which is firmly anchored on the machine outside the tool plate.
In another preferred embodiment the cage is provided on its outer surface with stop protrusions, through which screws are drawn through, which are fastened on one side to the support flange and on the other side they have a head to stop the cage by hitting on the stop protrusion.

Description of drawings

The invention will be described by use of drawings in which Fig.1 is a view of the tool for embossing of aerosol containers in assembled state, Fig. 2 shows the tool of Fig. 1 exploaded into individual structural items, Fig. 3 is a sectional view of the tool before starting the operation of embossing, Fig. 4 is the same sectional view of the tool while the operation of embossing in on, Fig. 5 is a sectional view of a tool with the variant embodiment of the stops, Fig. 6 is an overall view of a tool plate with tool, which is in the basic position prior to moving up to the container, Fig. 7 is an overall view of a tool plate with tool, which is in the working position with the tool mounted on the container, and Fig. 8 is a scheme of the creation of an electromagnetic field around the container in the embossing field.

Preferred embodiments of the invention

In Fig.1 is a view of the tool 1 for embossing of aerosol packaging containers in assembled state, therefore, before the placement onto the tool plate, where are also other tools, particularly shaping tools for manufacturing of the container. The embossing tool consists of a flange 2, by which the embossing tool 1 is mounted on the tool plate in the usual way. There is an outer tube 3 on the flange 2, in which a support tube 10 with a support flange 9 is inserted and there is a casing 5 mounted on it. Electric installation is placed on the opposite side in the support tube 10. The casing 5 is box-shaped and has openings 19 on each side, in which pressing inserts 7 by their projections are fixedly mounted. The casing 5 is then closed from the front by a cover 6. The end of the container 8 is also seen at a time when is inserted into the embossing tool 1 and embossing is going on.
In Fig. 2, where the embossing tool 1 is shown in an exploaded view, is very well seen its internal structure and function of each part. In the following description only the relevant parts will be described. Various common connecting pieces are not necessary to comment, as their arrangement is well known to those who are skilled in the art.
It is again seen the flange 2 with the outer tube 3, in which the support tube 10 with the support flange 9 is inserted and the casing 5 is mounted on it. The casing 5 is a part of a forming unit 26, which is best seen in Fig. 4, and its other part is a cage 11 slidably arranged inside of the casing 5, on which a guide tube portion 21 on the flange 14 is mounted and the guide tube portion 21 is slidably mounted in the supporting tube 10. Mutual springing of the stable support tube 10 and the sliding cage 11 is provided by press springs 15. The cage 11 also has a box shape with openings 18 in the walls, which are after assembling below the openings 19 in the casing 5. In this openings 18 forming segments 13 are then arranged. In the cavities of the pressing inserts 7 bearings 12 on axes are arranged, which have the function of wheels. Pressing inserts 7 and bearings form a pressure body 25. This will be discussed later. Under this pressure body 25 with pressing inserts 7 with bearings 12 are arranged forming segments 13 are arranged, which have an outer shaped surface 16 with transverse rest grooves 20 and an inner forming surface 17.
How mentioned, components are assembled as it is shown in Fig. 3, which is a cross-section of an assembled tool before moving of the embossing tool 1 on the container 8 and before starting the operation of embossing. It is seen that the cage 11 is connected to the flange 14 and its tube portion 21 is slidably mounted within the support tube 10. The tubular tube portion 21 is provided at its end with an inner stop ring 24. Its function will be discussed later. The flange 14 has an outer stop surface 23 and in the support tube 10 is again an inner stop surface 22. The outer stop surface 23 and the inner stop surface 22 are in the basic position at a distance. In order to provide defined movement of the tool parts back, when the press spring 15 is in function, the cage 11 is provided on its outer surface with stop protrusions 37, through which screws 38 are brought, which are fastened on one side to the flange 9 and from the other side they have a head. When the cage 11 returns to the basic position, it stops by hitting the head of the screw 38 on the stop protrusion 37. These components are seen in Fig.2
Conversely, in the next step, which is illustrated in Fig. 4, when the tool is already mounted on the container 8, just touch of these inner and outer stop surfaces 22,23 terminates movement of the cage 11 with forming segments 13. This contact of the stop surfaces 22,23 occures due to the pressure of the stable positioned container 8 to the inner stop ring 24 on the tube portion 21.
In the finishing phase, when the edge of the container 8 pushes the inner stop ring 24 ahead, due to the aforementioned coupled movement of the tube portion 21 and of the cage 11 the transverse rest grooves 20 are on the shaped surface 16 pushed away and bearings 12 on the pressing inserts 7 are getting onto the raised part of the shaped surface 16 and they perform its pressure function and push the forming segments 13 on the outer surface of the container 8. When the movement of the container stops, the current is let to flow into the coil 30 which is inside of the tool 1 and to the container 8 itself, and it causes electromagnetic forming in the area of contact of forming segments 13 and of the wall of the container 8. Wall of the container is thus pushed into the die in the forming segments 13 and the permanent deformation occurs, resulting in the creation of the desired relief on the wall of the container, which protrudes from its surface. The dies can be only on some forming segments 13, or on all of trhem, and the relief thus may be continuous along the whole part of formed circumference of the container 8. When pushing is finished, all forming segments 13 are locked into a compact die. Inside the support tube 10 on its free end a chuck 31 is inserted, which is tightened by a locknut and holds the coil which is placed in the tool. The coil is discussed in detail in relation to Fig. 8.
After completion of electromagnetic forming, press springs 15 are activated that push the tube portion 21 with the cage 11 back. Due to this, bearings 12 of the pressing inserts 7 move to the transverse rest grooves 20 on the shaped surface 16 and forming segments 13 thus move away from the wall of the container 8 and it creates a gap which is greater than the height of the relief and the embossing tool 1 and the tool plate are pushed into the basic position on the machine.
The above described inner and outer stop surfaces 22,23 are suitable when working with containers, which have a sufficiently rigid wall, which reliably pushes the inner stop ring 24 ahead without warping of the wall.
If the walls of the container are not sufficiently rigid 8, we can use an alternative shown in Fig. 5, with a draw bar 27 connected with the tube portion 21 ended by the stop surface 28, which would be blocked in a certain phase of the operation at the stop surface 29 of the holder 30, firmly anchored on the machine, outside of the tool plate. In this embodiment, the walls of the container would not be strained to pressure.
On the Fig. 6, there is an overall view of the tool plate 34 with the embossing tool 1, which is in the basic position prior moving up to the container 8 which is on the basic plate 35 in a clamping station 36. Fig. 7 is an overall view of the tool plate 34 with the embossing tool 1, which is in the working position with the embossing tool 1 fitted on the container 8 and performing the embossing working operation.
In Fig.8 there is a scheme of the creation of an electromagnetic field around the container in the embossing field. The setup for elecreomagnetic forming consists of the pulsed power generator 32, the inductor 33 including a fieldshaper, if applicable, the workpiece, aerosol can, and application-dependent further tool components such as form-defining dies.
The process is started by charging and subsequently discharging the capacitor of the pulsed power generator 32. Consequently, a damped sinusoidal current pulse flows through the inductor 33. This time-dependent current induces a corresponding magnetic field. If there is an electrically conductive workpiece in direct proximity to the inductor, a second opposedly directed current is induced shielding the magnetic field so that the field strength between container 8 and inductor 33 is significantly higher compared to the one on the container 8 surface facing away of the inductor 33.

Claims

Tool for electromagnetic forming of aerosol containers with relief protrusion, characterized in that it contains a support tube (10), a forming unit (26) seated firmly on the support tube (10), wherein the forming unit (26) consists of a hollow casing (5) with a movably arranged hollow cage (11) inside, wherein both the casing (5) and the cage (11) are provided on their walls with openings (18,19) which overlap themselves in an assembled state, further the forming unit (26) contains a pressure body (25) fixedly arranged in openings (19) of the casing (5), the pressure body (25) touches from above the forming segments (13) movably arranged in radial direction in openings (18) of the cage (11), wherein to the cage (11) is towards to the supporting tube (10) a tube guiding portion (21) adjoint, this tube guiding portion (21) is slidably arranged in the supporting tube (10), wherein between the supporting tube (10) and the cage (11) press springs (15) are mounted, the embossing tool (1) is further provided with cooperating stops for defined insertion of the container into the tool (1), wherein the casing (5) is on its free end provided with a cover (6) to prevent falling out of the cage (11) and inside of the embossing tool (1) a coil (30) for electromagnetic forming is arranged.
Tool according to claim 1, characterized in that the pressure body (25) is formed by a pressing insert (7) with bearings (12) arranged in the opening (19) of the casing (5).
Tool according to claim 1 and 2, characterized in that the forming segments (13) have an outer shaped surface (16) with transverse rest grooves (20) and an inner forming surface (17).
Tool according to claim 1, characterized in that the stops are formed as an outer stop surface (23) on the flange (14) of the tube portion (21) and as an inner stop surface (22) in the support tube (10).
Tool according to claim 1, characterized in that the stops are formed as a stop surface (28) made on the end of the draw bar (27) which is connected to the tube guiding portion (21) and as a stop surface (29) made on the holder (30) which is firmly anchored on the machine outside the tool plate.
Tool according to claim 1, characterized in that the cage (11) is provided on its outer surface with stop protrusions (37), through which screws (38) are drawn through, which are fastened on one side to the support flange (9) and on the other side they have a head to stop the cage (11) by hitting on the stop protrusion (37).