WO1998003278A1

WO1998003278A1 - Press device for the leaktight sealing of a can wall with a separation element

Info

Publication number: WO1998003278A1
Application number: PCT/EP1997/003144
Authority: WO
Inventors: Werner Grabher
Original assignee: Werner Grabher
Priority date: 1996-07-21
Filing date: 1997-06-17
Publication date: 1998-01-29
Also published as: DE59602106D1; AU3176597A; EP0824980B1; ZA976111B; ATE180700T1; EP0824980A1

Abstract

The invention concerns a press device for producing cans in which a first contact surface (46a) of the can wall (46) is brought into close connection with a second contact surface (47a) of a base, lid or closure membrane (47). The press device comprises a pressing surface (49) composed of at least two partial surfaces (30') of at least two pressing parts (30). The partial surfaces (30') each extend along part of a peripheral line in a plane lying substantially perpendicular to the can axis (37). In order to attain uninterrupted pressing along the entire periphery, even when the pressing parts (30) in the pressing position deviate somewhat from the optimum mutual arrangement owing to tolerances of the can, the partial surfaces (30') that adjoin each other in the axial direction are disposed such that at least one partial surface (30') is always present along the entire periphery. The interruption regions occurring in the peripheral direction between partial surfaces (30') of a peripheral line are displaced in the peripheral direction with respect to the interruption regions of another peripheral line.

Description

Press device for sealingly connecting a can wall to a separating element

The invention relates to pressing devices according to the preamble of claim 1.

In the manufacture of various cans, which comprise a can wall running around the can axis and at least one separating element running at least partially transversely to the can axis, a first contact surface of the can wall is mated with a second contact surface of the separating element m that is tight to the first contact surface of the separating element brought. The separating element is designed, for example, as a base, cover or closure membrane.

In the case of cans, it is known to provide the bottom and / or lid or at least partial areas of the first and / or second contact surfaces with sealing wax in order to be able to achieve a tight connection by pressing the contact surfaces together and applying heat. To achieve a good pressing effect, pressing devices are used, for example, in which the - in particular ring-shaped - contact surfaces between the inner and outer conical belt parts are introduced, while the ring parts are then moved against one another by an axial movement. The conical press surfaces also make the connection conical, which is not desirable for many cans.

In order to also achieve essentially cylindrical connecting areas or interconnected contact surfaces, at least one pressing surface must be radially adjustable so that it can be pressed against the contact surfaces after insertion. For this purpose, collets with axial lamellae are used, which in the open state are slightly conical to the outside or inwards to accommodate the cylindrical contact surfaces. For pressing, the lamellae are slightly sam en- or pressed. There is no pressure in the areas of the gap between the lamellae, so that cannulas can remain open through the contact area. The cannulas are undesirable, axially aligned passage channels between the contact surfaces.

In a further solution according to the prior art, for example, a cylindrical tube piece with a circular cross section is cut along square sides with axially parallel cut surfaces, the corners of the square lying m or outside the wall of the tube piece and the cut surfaces each in a central area guide the inside of the pipe section. This creates four outer and four inner, essentially triangular, pressed parts, each with a part of the cylindrical pressing surface. For pressing, the outer pressed parts, and the inner pressed parts, which are carried along by them, are pushed together. Because the sliding surfaces between the outer and the inner pressed parts run transversely to the contact surfaces to be pressed, the acute-angled ends of the pressed surfaces of the inner pressed parts can lead to injuries or wrinkles in the pressed contact surfaces. To keep these errors as small as possible, the pressure must be as precise as possible with the radius of the pipe section, which is often not possible due to the tolerances of the can parts.

When pressing from the inside, at least one press part, but preferably several press parts, with a convex press surface, must be movable from a feed position with a smaller press surface circumference and a press layer with a larger circumference. The size of usable dividing disks and / or elastic rings is adapted to the smaller circumference in the feed position in which the can parts of the press device can be fed. In the press position, the press surface of the pressed parts does not extend along the entire larger circumference, so that at least one free space adjoins the contact surface to be pressed. No pressure occurs in the area of the free spaces, which leads to a leaky connection, in particular to the formation of cannulas. When pressing from the outside, at least one pressed part, but preferably several pressed parts with a concave pressing surface, must be able to be moved from a feed position with a larger pressing surface circumference to a pressing layer with a smaller circumference. The parts that can be moved from the outside in the press position can be dimensioned such that they form a paragraph-free, closed circumferential line when resting against the anemander. When colliding, in particular in the final phase, in which the interruptions between the pressing surfaces disappear, the pressed can material tends to be caught in the interruptions. To achieve the closed pressing surface, the pressed parts must always be brought into the same end position during the pressing, which is not always guaranteed with variations in the thickness of the can material or the can cross-section.

The object of the invention is to create a pressing device which is suitable for the annular, tight connection of a can wall with a separating element and prevents the formation of cannulas or injuries. The

The pressing device should be usable for cans made from all known can materials and, with the corresponding shape, should enable cylindrical, conical or any other closed or ring-shaped connection areas to be formed. The pressing surfaces should be able to be convex or concave, so that the pressing can take place from the inside of the can and / or from the outside of the can.

The problem is solved by realizing the generic features together with the characterizing features of claim 1. Preferred embodiments are characterized by features of the dependent claims.

The pressing device comprises a pressing surface, which is composed of at least two partial compartments of at least two pressed parts. The partial areas each extend along a part of a circumferential line in a plane which is essentially is perpendicular to the main or can axis. In order to achieve an uninterrupted pressing along the entire circumference, even if the pressed parts in the press position deviate somewhat from the optimal mutual arrangement due to the tolerances of the cans, the partial surfaces adjoining one another in the axial direction are arranged in such a way that along the entire At least one partial area is always provided circumferentially. The interruption regions which arise in the circumferential direction between partial surfaces of a circumferential line are shifted in the circumferential direction with respect to the interruption regions of another circumferential line. The partial areas are arranged in layers in the axial direction, at least two, but preferably three, layers being provided. The adjoining partial surfaces of different layers may be formed by adjoining parts in the axial direction. However, they are preferably formed by pressing surfaces of the pressed parts which are edge-like on both sides in the circumferential direction, the steps of the pressed parts adjoining one another in the circumferential direction fitting into one another.

The pressed parts are preferably designed in the form of part disks or part rings and are mounted with their central region essentially radially movable relative to the main axis. During the radial movement between the feed and the press position, the degree of overlap of the pressed parts varies in that the mating steps or layers of the pressed parts more or less interlock. In the case of convex press surfaces intended for pressing from the inside, the overlap m is maximum in the feed position and minimal in the press position. Accordingly, in the case of concaves intended for external pressing,

Press areas the maximum overlap in the feed position and minimal in the press position. The guaranteed overlap ensures that there are no pass-through-free areas when pressing from the inside and that no damage or clamping of can material is possible across the entire contact area when pressing from the outside. In order to achieve a good interaction of the partial surfaces, the outer radius of the convex pressed parts may be a little smaller than - but in particular essentially the same size as - the radius of the contact surface to be pressed. Correspondingly, the pressing surface formed from the partial areas in the overlap area may deviate somewhat inward from the circular shape, but is essentially circular, in particular in the pressing position. In the case of connection areas which have no circular cross sections, the respective cross section is essentially obtained in the press layer. Similarly, in the case of pressed parts with a concave pressing surface, the inner radius of the pressed parts is the same size or slightly larger than the radius of the contact surface to be pressed.

The longitudinal contour of the pressing surfaces in one plane through d e

The main axis can be adapted to the desired longitudinal contour between the contact surfaces to be connected to one another.

A radial movement of the pressed parts has the advantage that the change from the feed position to the pressed position is made possible by an extremely small movement of the pressed parts, with essentially no frictional movement occurring between the contact surface and the pressed parts in the circumferential direction. Due to the small movement and the small friction, only a small force is required to actuate and in particular to reset the pressed parts. In the preferred embodiments, the movement into the press position takes place due to the movement of an actuating element. When pressed from the inside, the actuating element is preferably a conical or circular cone part which can be displaced in the axial direction and on whose outer or actuating surface there are conical connecting surfaces of the pressed parts. When pressing from the outside, a section of a circular cone inner surface is preferably used as the actuating surface, on which conical part-shaped outer surfaces of the pressed parts lie as connecting surfaces. In order to achieve the desired movement, the pressed parts are in particular m in a straight guide oriented essentially perpendicular to the main axis. leads, and the actuator is substantially movable along the major axis. When the actuating element moves in a first actuating direction, the pressed parts are pressed against the can contact surfaces; In a second direction of movement, the pressed parts can preferably be reset by spring elements or pressed against the actuating element.

Because of the relative movement between the actuating element and the pressed parts, the contour lines of the actuating surface and the connecting surfaces lying opposite one another in the normal plane of the main axis also shift. In order to prevent clamping effects between the parts lying against each other, the radii of the contour lines are selected so that the radius of the outside line is always larger or the same as the radius of the inside line in the entire area between the feed and the press position. In order that the power transmission is optimal during pressing, essentially the same radii are preferably assigned to one another in the area of the pressing position, and the surfaces accordingly lie essentially close together. In the area of the feed position, the surfaces essentially abut one another only along a straight surface line.

When using clamping rings that can be pressed on, the friction movement is significantly higher and there is also a risk of non-round pressings. In addition, when using open rings, the only interruption is essentially as large as the total of all interruptions between several press parts that may be provided. Even if at least two press rings with mutually offset interruptions are provided, the large interruptions can lead to unsightly connecting sections.

The connection between the contact surfaces pressed against one another is frequently achieved by heating at least one sealing layer applied to a contact surface. The heat is preferably supplied via the pressing surface. To do this, a good heat transfer from the pressing device to the contact surfaces or the pressing surfaces can be achieved. It has now been shown that this cannot be easily guaranteed when using elastic rings. An optimal heat flow is achieved with pressed parts in the form of belt parts. In this case, at least one heating element is preferably in heat-conducting contact via a heat-conducting body with a transfer surface of the pressed part which is in particular normal to the main axis and is sufficiently large for the desired heat flow. In the pressed part, the heat flows directly to a partial surface without further contact transition. If necessary, a heating element could be connected to each pressed part. However, a heating device is preferably provided which connects with a heating surface to the transfer surfaces of all pressed parts, the transfer surfaces slidingly moving along the heating surface when the pressed parts move. In order to adapt the pressing surface to the different can cross-sections, only the pressed parts have to be replaced, the heating device remains on the pressing device.

Pressing devices according to the invention can be used in a wide variety of configurations. Due to the optimally shaped and uninterrupted pressing surface, pressing can usually be done without a counterpressing surface, at least in the case of seal joints. In the case of separating elements or can endings with contact surfaces which abut the inside or outside of the can jacket, pressing with a convex or concave pressing surface from the inside or outside is sufficient. The stability of the can wall is very high when pressing with a press surface of the same shape. The possibility of pressing without a counterpressing surface is a further advantage of the pressing device according to the invention and enables, for example, the attachment of a can end after the attachment of the other can end or a separating membrane. Further details of the invention will become apparent from the following description of exemplary embodiments explained in the drawings. Show it:

Fig.la a section through a press device with pressed parts guided by a fixed stamp surface, the feed position being shown on the left and the press position on the right, FIG. 1b a plan view of the press parts, FIG. 2 a section through a press device with 3 shows a perspective view of the pressed parts, FIG. 4 shows a top view of the pressed parts for an oval box, FIG. 5 shows a top view of the pressed parts for a hexagonal box, and

6 shows a section through a pressing device for pressing from the outside.

According to FIG. 1, a pressing device according to the invention comprises pressed parts 30, each of which abuts an actuating surface 32 of a conical actuating element 33 with a conical connecting surface 31. In order to ensure that the connection surfaces 31 always rest on the actuation surface 32, a restoring means, preferably at least one restoring spring 34, is assigned to each pressing element 30. The return springs 34 press the pressing elements 30 radially against the actuating element 33 by means of a heat-conducting body 36 which is held by a fixed holding part 35 equipped with heating cartridges 51a. The pressing parts 30 can be moved radially to the axis 37 by moving the actuating element 33 along an axis 37. For actuation, an actuating rod 38, which is guided through the holding part 35 and the heat-conducting body 36, is connected to the actuating element 33. To guide the actuating rod 38, in particular a slide bearing 36a is provided in the heat element. In order to guide the pressing part movement, the heat-conducting body 36 has heating surfaces 39 which are arranged vertically to the axis 37 and which bear against transfer surfaces 40 of the pressing parts 30. The end surfaces 41 facing away from the transmission surfaces 40 are guided from the inside of a fixed stamp surface 42. The stamp surface 42 is connected to the heat-conducting body 36 via fastening point 43a and spacers 43b, which go through through openings 43c of the pressed parts 30. Instead of the guide with the stamp surface 42, the guide can be achieved, for example according to FIG. 2, by radial guide slots 44 in the heat-conducting body 36 and by extensions 45 of the pressing elements 30 guided therein.

When a cylindrical can 46 is supplied with a first contact surface 46a arranged on the inner surface of the can 46, a second cylindrical contact surface 47a of an inserted separating membrane 47 bears against this contact surface 46a, for example. The can is optionally received by the free end of a displaceable centering ring 13, in particular comprising a feed area, and by moving the

Centering ring guided over the pressed parts 30. The centering ring 13 is guided axially parallel on the heat-conducting body and / or on guide pins 14 and is pressed away from the holding part 35 by at least one compression spring 15. The bolts 14 protrude from a disk 14a, which is fastened to the heat-conducting body 36 with screws 14b. The heat-conducting body 36 is fastened to the holding part 35 with screws 48.

In the inserted state, the contact surfaces 46a and 47a enclose the pressing surface 49 formed by the pressed parts

The contact surfaces 46a, 47a are pressed by the movement of the pressed parts 30 from the feed position to the pressed position. The centering ring 13 is optionally designed such that a partial surface can be used as a counterpressing surface. In order to be able to achieve a seal directly during pressing, the

Heat conducting body 36 emitted heat from the heating surfaces 39 via the transfer surfaces 40 to the pressing surface 49. The temperature The temperature of the heat-conducting bodies is measured by a temperature sensor 50 and used to control the supply of the heating cartridges 51a. The supply takes place via feed lines 51.

The design of the pressed parts 30 is illustrated by the top view in FIG. 1b and the perspective illustration in FIG. 3. In the illustrated embodiment, six pressed parts 30 are put together to form a press ring. In this case, three pressed parts 30 are the same. In the compilation, different pressed parts 30 alternately adjoin each other. The pressing surfaces 30a of the pressed parts 30 have a step-like edge in the circumferential direction, the one pressed part having ascending and descending steps 30b on one side and descending on the other side, the other pressing parts having reversed ascending or descending steps 30b. In the illustrated embodiment, stages of various pressed parts that adjoin one another in the axial direction always have an overlap. The pressing parts 30 are moved radially by the axial movement of the actuating element 33; the overlap also varies. Since the radial movement is very small, the interruptions in

Circumferential direction can be chosen very small. In Figure 3 they are shown exaggerated. Radial bores 34a serve to receive the return springs 34.

In order to simplify the production of the pressed parts 30, these are, as indicated on a pressed part in FIG. 3, composed of differently sized disc parts with partial compartments 30 '. Instead of a fixed connection, the disk parts can optionally be guided radially by a common guide device. It goes without saying that a wide variety of step shapes 30b adapted to one another can be provided. By using a large number of steps, the step height can be selected to be very small. Instead of six pressed parts 30, any, preferably a larger, and in particular an even number of pressed parts 30 can be used. FIGS. 4 and 5 show pressed parts 30 which are designed for pressing cans with two semicircular side areas and a straight middle area or with a hexagonal cross section. The pressed parts 30 adjoin one another with steps 30b lying against one another in an overlapping manner. The

Pressed parts 30 are shown in a receiving position in which the steps 30b abut one another.

6 shows an example of a pressing device for pressing from the outside. A first and second heat conducting part 36a and 36b of a heat conducting body 36 is fastened to the holding part 35 with the heating cartridges 51a. A radially projecting guide groove 52 is formed on the second heat-conducting part 36b, which fits in the guide slots 53 of part-shaped press parts 30. The guide slots 53 are open against the axis 37 hm and, together with the guide groove 52, form a radial guide m which the pressed parts 30 are radially movable but axially fixed.

The pressing surfaces 49 of the pressed parts 30 are directed inwards against the axis 37. In order to move the pressing surfaces inward for pressing together contact surfaces of a can, the pressing parts 30 comprise outwardly directed conical connection surfaces 31 which bear against an inwardly facing, conical actuating surface 32 of an annular actuating element 33. In order to ensure that the connection surfaces 31 always rest on the actuating surface 32, a restoring means, preferably at least one restoring spring 34, is assigned to each pressing element 30. The return springs 34 press the pressing elements 30 radially outward from the second heat-conducting part 36b against the actuating element 33. The pressing parts 30 can be moved radially to the axis 37 by moving the actuating element 33 in the direction of the axis 37. For actuation, at least one actuating rod 38 ′ is connected to the actuating element 33 via a connecting device 56 m t.

In order to ensure good heat transfer from the heat-conducting body to the pressed parts 30, the first and the second are Thermally conductive part 36a and 36b heating surfaces 39 formed, connect to the transfer surfaces 40 of the pressed parts 30. If necessary, an ejection device is provided which makes 54 cans ejectable with an ejection surface arranged between the pressed parts. The ejection surface 54 is one

Ejection rod 55 connected and movable in the direction of the axis 37 by actuation thereof.

The invention is not restricted to the illustrated embodiments. It is clear to the person skilled in the art that, in addition to circular pressing, any concave pressing surfaces, in particular pressing surfaces with oval and polygonal, preferably with hexagonal, cross sections can also be used for the external pressing.

Claims

PATENT CLAIMS

1. Press device for sealingly connecting a can wall (46) to a separating element (47) with at least two pressing parts (30), which together form an adjustable pressing surface (49) arranged around an axis (37) and consisting of partial surfaces (30 ') , characterized in that the partial surfaces (30 ') each extend along a part of a circumferential line in a plane which is substantially perpendicular to the axis (37), and the interruptions between partial surfaces (30') of a first circumferential line with respect to the interruptions of a other circumferential line are offset in the circumferential direction, so that the pressing surface (49) has no continuous interruptions in the axial direction.

2. Device according to claim 1, characterized in that the partial surfaces (30 ') are arranged in layers in the axial direction, at least two, but preferably three layers are provided and the partial surfaces (30') of adjoining layers are designed to overlap in the circumferential direction .

3. Device according to claim 1 or 2, characterized in that the adjoining partial surfaces (30 ') of different layers are formed by parts adjoining one another in the axial direction, but preferably by pressed parts (30) bordered on both sides in the circumferential direction, whereby the steps (30b) of the pressing parts (30) adjoining one another in the circumferential direction fit into one another.

4. Device according to one of claims 1 to 3, characterized in that the pressed parts (30) are part-disk or part-ring-shaped and in a substantially normal to the axis (37) straight guide (39, 42; 44, 45; 52 , 53) are mounted with their central region essentially radially movable, the degree of overlap of the partial surfaces (30 ') being different Layers in the radial movement between the feed and the press position varies in that the mating steps (30b) or layers of the pressed parts (30) engage more or less with each other.

5. Device according to one of claims 1 to 4, characterized in that a convex or concave pressing surface (49) is provided for pressing from the inside or outside, and preferably in a pressing surface with a circular cross-section, the outer radius of the convex or

The inner radius of the concave pressed parts (30) is the same as - or a little smaller or a little larger than - the radius of the contact surface (46a, 47a) to be pressed, with the pressing surface (49) formed from the partial pockets (30 ') in the overlap - Lapping areas may differ somewhat inwards or outwards from the circular shape, but is preferably essentially circular in the pressed position.

6. Device according to one of claims 1 to 4, characterized in that for a pressing from the inside or outside pressing parts (30) are provided, whose common inward or outward pressing surface (49) consists of flat parts, preferably one Part of the pressed parts (30) comprises two flat partial surfaces which adjoin one another at connecting edges.

7. Device according to one of claims 1 to 6, characterized in that the pressing surface (49) is at least partially cylindrical and / or conical and is optionally adapted to a flanged can end.

8. Device according to one of claims 1 to 7, characterized in that at least one heating element with a preferably normal to the main axis of the transfer surface before a pressing part (30) is in thermal contact, preferably a heating surface (39) of a heat-conducting body (36) the transmission surfaces (40) of all pressed parts (30) connects and the heating surface (39) serves as a guide surface for the movement of the pressed parts (30).

9. Device according to one of claims 1 to 8, character- ized in that an actuating element (33) movable in the axial direction is provided, which has a conical actuating surface (32) arranged around the axis (37), on which conical connecting surfaces (31 ) of the pressed parts (30), whereby to achieve the desired radial movement of the pressed parts (30) they are guided radially and can be pressed against the actuating surface (32) by means of restoring elements, in particular spring elements (34).