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Patent Searching and Data


Title:
SEALABLE CASING MATERIAL
Document Type and Number:
WIPO Patent Application WO/2017/055556
Kind Code:
A1
Abstract:
The present invention relates to a supply (MS) of flat film material (M), the flat film material (M) includes at least one layer of cellulose fiber material and has a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (120, 104) being aligned at least approximately parallel to each other, comprising connecting means (200) for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104) in order to form a tubular casing (T), wherein the connecting means (200) are arranged at least in the region of one of the first or second longitudinal edge(102, 104). The present invention further relates to a tubular casing (T) formed by a flat film material (M). a sausage-shaped product (S), like a sausage, comprising the tubular casing (M), a connecting device (50) for forming a tubular casing (M) from the flat film material (M), and a clipping machine (C) for producing sausage-shaped products (S), like sausages.

Inventors:
MEYRAHN, Joachim (Wingertstraße 28, Erzhausen, 64390, DE)
REITZ, Jürgen (Niddastraße 6, Eschborn, 65760, DE)
Application Number:
EP2016/073430
Publication Date:
April 06, 2017
Filing Date:
September 30, 2016
Export Citation:
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Assignee:
POLY-CLIP SYSTEM GMBH & CO. KG (Niedeckerstraße 1, Hattersheim, 65795, DE)
International Classes:
B65B9/06; A22C13/00
Foreign References:
US4410011A1983-10-18
EP0779324A21997-06-18
US4478670A1984-10-23
US4399839A1983-08-23
US4396039A1983-08-02
EP0508226A11992-10-14
US4475895A1984-10-09
EP1611792A22006-01-04
Attorney, Agent or Firm:
EISENFÜHR SPEISER PATENTANWÄLTE RECHTSANWÄLTE PARTGMBB (P. O. Box 31 02 60, Munich, 80102, DE)
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Claims:
Claims

1 . A supply (MS) of flat film material (M), the flat film material (M) includes at least one layer of cellulose fiber material and has a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (102, 104) being aligned at least approximately parallel to each other and comprising connecting means (200) for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104) in order to form a tubular shaped casing (T), wherein the connecting means (200) are arranged at least the region of one of the first or second longitudinal edge (102, 104).

2. A tubular casing (T) formed by a flat film material (M) of a supply (MS) of flat film material (M), the flat film material (M) includes at least one layer of cellulose fiber material and has a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (102, 104) being aligned at least approximately parallel to each other, wherein the flat film material (M) comprises connecting means (M) arranged at least in the region of one of the first or second longitudinal edges (102, 104), for connecting the flat film material (M) in the region of the first and second longitudinal edge (102, 104).

3. A sausage-shaped product (S), like a sausage, comprising a tubular casing (T) having a first end and a second end, wherein the tubular casing (T) is filled with filling material and closed at its first as well as its second end by a closure means (CC), like a closure clip,

wherein the tubular casing (T) formed by a flat film material (M) of a supply (MS) of flat film material (M), the flat film material (M) includes at least one layer of cellulose fiber material and has a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (102, 104) being aligned at least approximately parallel to each other, wherein the flat film material (M) comprises connecting means (200) arranged at least in the region of one of the first or the second longitudinal edge (102, 104), for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104).

4. A connecting device (50) for forming a tubular casing (T) from a flat film material (M) of a supply (MS) of flat film material (M),

the flat film material (M) including at least one layer of cellulose fiber material and having a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (102, 104) being aligned at least approximately parallel to each other, wherein the flat film material (M) comprises connecting means (200) arranged at least in the region of one of the first or second longitudinal edge (102, 104), for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104),

the connecting device (50) comprises means (52) for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104).

5. A clipping machine (C) for producing sausage-shaped products (S), like sausages, comprising a supply (MS) of flat film material (M), a filling tube (10) for feeding filling material into the tubular casing (T) stored on the filling tube (10) and being closed at the front end by at least one closure clip (CC) and a closing device (40) for applying and closing the at least one closure clip (CC), wherein the tubular casing (T) is formed by the flat film material (M) of the supply (MS) of flat film material (M), the flat film material (M) includes at least one layer of cellulose fiber material and has a longitudinal extension, an upper surface (106), a lower surface (108), a first longitudinal edge (102) and a second longitudinal edge (104), the first and second longitudinal edges (102, 104) being aligned at least approximately parallel to each other, the flat film material (M) comprising connecting means (200) arranged at least in the region of one of the first or second longitudinal edge (102, 104), for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104),

the clipping machine (C) comprises a connecting device (50) for forming a tubular casing (T) from a flat film material (M) having means (52) for connecting the flat film material (M) in the region of the first and second longitudinal edges (102, 104).

Description:
Sealable casing material

The present invention relates, amongst others, to a flat film material which may be formed into a tubular casing, for producing sausage-shaped products.

In the production of sausage-shaped products, like sausages, it is known that a filling material, like sausage meat, is fed through a filling tube of a filling machine, like a clipping machine, into a tubular or bag-shaped packaging casing which is temporarily stored on the filling tube and which is closed at its front end, i.e. the end pointing in the feeding direction of the filling material, by, for example, a closure means, like a closure clip, or by a fusing line at this end, respectively. The tubular packaging casing is pulled-off from the filling tube while being filled with filling material fed into the casing by the feeding pressure. After a predetermined volume of filling material has been filled into said tubular packaging casing, gathering means with a first and a second displacer unit which can each be formed by a pair of reversibly moveable displacement elements, form a plait-like portion of the tubular packaging casing, which is at least substantially free of filling material. By moving the first and second displacer units relative to each other, the length of the plait-like portion may be varied. For example, products being completely filled with filling material, or tightly filled, are usually provided with a relatively short plait-like portion whereas products being only partly filled with filling material are provided with a relatively long plait-like portion to produce a slack filled sausage-shaped product. The clipping machine then closes at least one closure means which corresponds to the closure means at the front end of the packaging casing, at the plait-like portion forming the rear end of the sausage- or bag-shaped product, i.e. the end pointing opposite to the feeding direction by respective closing tools which are reversibly movable towards the plait-like portion and the functionality of which is adapted to the type of closure means, used for closing the first as well as the second end of the packaging casing.

The casing material may be provided as a pre-packaged supply of shirred casing material stored on a carrier tube, which is positioned on the filling tube of a clipping machine, or the casing may directly be transferred from a supply roll onto the filling tube. Such systems are known from EP patent application 0 508 226 in which a pre-packaged supply of tubular casing is disclosed, and US patent 4,475,895 in which the transfer of tubular casing material directly onto the filling tube is disclosed

Alternatively, the casing material may be a film strip which is bent into a tube by a forming shoulder positioned on the filling tube of the clipping machine. The film strip is a plastic film which includes at least one layer of sealable material for sealing the longitudinal edges of the film strip which overlap each other, by means of a sealing device, in order to form a tubular casing. Such a supply of casing material and a sealing device are known from EP patent application 1 61 1 792.

Using a pre-packaged supply of tubular casing has the advantage that no additional sealing devices are needed, and that a great variety of casing materials may be processed. On the other hand, the size of the supply of tubular casing material, i.e. its length, which may be stored on the filling tube, is limited depending on the length of the filling tube. Accordingly, also the number of sausage-shaped products which may be produced is limited, and a refill of tubular casing material is necessary, which takes production time and reduces the efficiency of the production. In case that tubular casing is formed from a flat film strip, the size of the supply of the film strip may be selected nearly independently from the kind of clipping machine, whereby a refill of film strip may be reduced to a minimum. However, the material for the film strip is limited as to contain at least one layer of sealable material which, conventionally, is a plastic layer. Accordingly, the film strip may not be used in the production of any kind of sausage-shaped products and, in the production of sausages, not any kind of filling material, i.e. sausage meat, may be filled into said casing material.

Furthermore, dependent on the kind of the casing material, not any kind of sealing devices or sealing methods may be used. In some cases the casing material has to be watered for enabling a stretching of the casing material during the filling process, and, for ensuring that the casing material may tighten, e.g. during drying. Such casing material may not be sealed by heat.

In the case that a casing material is heat-sealed, which is a commonly known method during which a continuous seal or seam is formed to the overlapping edges of the casing material for forming a tubular casing, the seal or seam may have other characteristics than the remaining casing material, like its water- permeability, flexibility or rigidity, which may have an influence to the quality of the product.

It is an object of the present invention to provide a supply of flat film material which overcomes the above mentioned disadvantages, and which allows the production of a great variety of different kinds of sausage-shaped products.

The flat film material according to the present invention may be used for forming a tubular or bag-shaped packaging casing for producing sausage-shaped products, like sausages. The inventive flat film material may be provided as a supply of flat film material. Alternatively, the inventive flat film material may also be formed into a tubular or bag-shaped packaging casing immediately after being produced. The flat film material according to the present invention includes at least one layer. Naturally, the flat film material may also comprise two or more layers. In this case, the layers may have different properties, and may be made from identical or different base materials.

According to a preferred embodiment of the present invention, the layer, or at least one of the layers, may be made from or includes cellulose fiber material.

According to the present invention, there is provided a supply of flat film material having a longitudinal extension, an upper surface, a lower surface, a first longitudinal edge and a second longitudinal edge, the first and second longitudinal edges being aligned at least approximately parallel to each other, the longitudinal edges may abut against each other or overlap each other for being connected, and comprising connecting means for connecting the flat film material in the region of the first and second longitudinal edges in order to form a tubular casing, wherein the connecting means are arranged at least in the region of one of the first or second longitudinal edge.

For forming a flat film material into a tube or tubular casing, in principle, there are two different methods. In a first method, a flat film material is bent about an axis being aligned with its longitudinal extension. That means, the connection line or seam formed by connecting the longitudinal edges of the flat film material, is arranged parallel to the central axis of the tubular casing. According to a second method, a tubular casing may be formed by wrapping the flat film material about a cylindrical carrier element, which e.g. may be the filling tube. The connecting or seam formed by the longitudinal edges of the flat film material extends in a helical shape about the central axis of the tubular casing.

It has to be understood that the present invention applies to both kinds of forming a tubular casing from a flat film material.

For establishing a connection between the longitudinal edges of the flat film material, said longitudinal edges may overlap each other. Alternatively, and dependent on the kind of the connecting means, it may be sufficient that the longitudinal edges abut against each other. In the following, the term "connecting the longitudinal edges" may include both, overlapping or abutting the longitudinal edges of the flat film material.

The term "abut" has to be understood such that the longitudinal edges of the flat film material are positioned laterally to each other for forming a tubular casing. In one embodiment, the longitudinal edges may be in direct contact with each other with no gap there between. In a further embodiment which is also understood under the term "abut", the longitudinal edges of the flat film material may be positioned closed to each other, but not being necessarily in direct contact over their entire length. There may be left a gap between said longitudinal edges, i.e. in order to adjust the diameter of the tubular casing or in order too balance variations in the width of the flat film material.

It is the core idea of the present invention to provide a flat film material which comprises connecting means at least in the region of at least one of its longitudinal edges. By means of said connecting means, the longitudinal edges of the flat film material may be connected such that a tubular casing is formed, by abutting or overlapping the longitudinal edges, which may be filled with a filling material, in order to produce sausage-shaped products.

Providing the connecting means in the region of the longitudinal edges of the flat film material saves costs, e.g. with regard to the quantity of connecting means, and enables specific designs of connecting means. Moreover, connecting means provided in the region of the longitudinal edges of the flat film material, have less influence to the flat film material, e.g. with regard to its specific properties, like its flexibility, stretchability or permeability.

One essential part of the present invention is the provision of connecting means which enable the forming of a tubular casing from nearly any suitable flat film material.

The connecting means may be provided in the region of one or both of the longitudinal edges of the flat film material. After overlapping or abutting the longitudinal edges to each other, in order to form a tube, the connecting means establish a permanent or temporary connection of the border area along the longitudinal edges of the flat film material.

It has to be noted that it may be sufficient to provide the connecting means only along one of the longitudinal edges of the flat film material. However, dependent on the flat film material and/or the kind of the connecting means, it may be necessary to provide connecting means along both longitudinal edges of the flat film material.

As the connecting means, various solutions may be used, which are provided in various designs or materials or combinations thereof.

Mechanical connecting means may be provided. Such mechanical connecting means may include a first connecting element provided in the region of one of the longitudinal edges, i.e. the first longitudinal edge, and a second connecting element which is provided in the region of the respective other or second longitudinal edge of the lat film material.

As one example of a mechanical connecting means, the connecting means may be realized by a hook and loop fastener. Accordingly, the first connecting element may be the "hook"-element, namely that portion of the hook and loop fastener carrying the hooks, whereas the second connecting element carries the "loops". It has to be understood that the hook and loop fastener has to be of such construction that a tubular casing including such connecting means, may be filled and closed on a clipping machine, preferably on a known clipping machine with known closure clips. Alternatively, minor adaptations at the clipping machine may be necessary, like using specific gathering elements or specific closure clips.

In other embodiments of a mechanical connecting means, the first and/or second connecting elements are such elements which may cooperate in any suitable manner for establishing a temporary or permanent connection. These elements may include any suitable form-fit or force-fit elements, or combinations thereof, like zipper elements. Specific fins or lamellar structures may be provided in the region of the longitudinal edges, which, when in closed contact, enable a connection therebetween.

Magnetic components may be provided in the region of both longitudinal edges of the flat film material for connecting the longitudinal edges of the flat film material for forming a tubular casing. The magnetic components may be formed by a thin layer extending continuously along the edges of the film material, or as particles arranged regularly or non-regularly along said edges of the film material.

As a further alternative material for establishing a connection between the longitudinal edges of the flat film material, minerals may be provided in the region of the longitudinal edges of the flat film material. Said minerals should have adhesive properties for enabling an at least temporary connection. Glimmer is one of the possible materials, which is a sheet silicate mineral with high inter- molecular forces between two adjacent layers. An additionally applied adhesive may strengthen the connection between said two layers.

In the case that zipper elements are provided, along one of the longitudinal edges of the flat film material, a first zipper element may be provided which interacts with a second zipper element provided along the respective other longitudinal edge of the flat film material. The first zipper element may include at least one longitudinally extending groove in which a longitudinally extending tongue or flange engages, and which forms the second zipper element, for establishing a connection between the longitudinal edges of the flat film material. The groove and the tongue may have a form-fit design including securing means, like hooks, for preventing an unintentional opening of the connection.

Naturally, also any combination of form-fit and force-fit elements may be provided. In the case that magnetic components are provided in the region of one or both of the longitudinal edges of the flat film material, additionally, flanges or skirts and corresponding grooves may be arranged such that they extend along the longitudinal edges or with an offset thereto, and that they may engage each other in order to take up forces in circumferential direction of the tubular casing. Besides mechanical connecting means, also other kinds of connecting means may be provided. In the following, the term "chemical connecting means" is used for non-mechanical connecting means, like adhesives or materials which are treated with heat, radiation or any other means, and which thereby change their structure or properties in order to securely connect the longitudinal edges of a flat film material for forming a tubular casing.

As one example of chemical connecting means, in the region of the longitudinal edges of the flat film material, an adhesive may be provided in the form of a line extending approximately parallel to one of the longitudinal edges of the flat film material, and on its outer surface. For forming a tubular casing, the respective other longitudinal edge of the flat film material is positioned such that the longitudinal edges overlap each other and that the line of adhesive is positioned there between. Alternatively, said line of adhesive may also be provided on the inner surface of the flat film material.

Alternatively, the adhesive may be provided on a separate stripe arranged along one of the longitudinal edges of the flat film material. Said stripe extends over the longitudinal edge of the flat film material, and additional adhesive is provided on said extension for being connected with the respective other longitudinal edge of the flat film material in order to form a tubular casing. In this case, the longitudinal edges may abut each other, or a small gap may be left between said longitudinal edges, in order to adjust the diameter of the tubular casing or for balancing variations in the width of the flat film material.

In order to prevent unintentional adhering of the film material, the line of adhesive may be covered. In the simplest case, a covering strip, e.g. made of paper, may be provided, which is removed immediately before forming the flat film material into a tube. Alternatively, a covering strip may be made of a pressure sensitive or a thermal sensitive material. When joining the longitudinal edges of the flat film material by using pressure, heat or a suitable radiation, this material may change its properties, e.g. neutralize its covering property, such that a removal of the covering strip is not necessary. As one example, a layer which does not need to be removed, may be formed by a dried surface of the adhesive, which may be reactivated by applying heat, radiation or the like.

In other embodiments, particles of material may be provided in the region of the longitudinal edges of the flat film material, which form the connecting means. Said particles should be encapsulated for preventing an unintentional activation, e.g. by heat or pressure. These particles may be arranged on the surface, the inner and/or outer surface, of the flat film material.

As an alternative, the particles may be provided within the flat film material, whereby an additional covering may be omitted.

The particles forming the connecting means may be provided as solid particles which are placed on the flat film material or which may be mixed into the material during the production process of the film material.

Alternatively, the substances for the particles may be provided in a solution or a dispersion that is applied to the surface of the flat film material. After a drying process, the particles remain on the surface of the film material.

In order to increase the bonding between the particles and the flat film material, a primer may be applied to the flat film material or the solution/dispersion including the substances forming the particles.

In the case that the particles are positioned within the flat film material, the film material has to be provided with a structure which enables an accommodation of said particles.

As an example, the flat film material may comprise more than one layer, such that the particles may be arranged between two adjacent layers. In such a case, at least one of the layers covering the particles, preferably that layer forming that portion of the surface of the flat film material that is overlapped for forming the tubular casing, should have such specific properties that the particle material may diffuse through this layer for interacting with the overlapping portion of the film material, in order to establish a connection between the overlapping regions of the flat film material, like sufficient permeability.

It is also possible that the flat film material comprises only one layer. In this case, the particles forming the connecting means, may be incorporated in the film material, e.g. during the production of the film material.

In a specific embodiment, said particles are polarizable. That means, said particles may be "activated" by electric or magnetic fields, whereby e.g. a magnetic field is generated in the particles. In the case that both longitudinal edges of the flat film material are provided with such particles, the connection between the longitudinal edges may be established by said "activated" polarized particles.

As further alternative connecting means, the region of the longitudinal edges of the flat film material may be prepared for being connected with an additional connecting element.

In one embodiment, the regions of the longitudinal edges of the flat film material are prepared for being sutured for forming a tubular casing. A suturing device may be arranged in the region of the filling tube, e.g. immediately downstream the forming shoulder which forms the flat film material into a tube. In preparation for being sutured, the regions of the longitudinal edges of the flat film material may include reinforcement, like a partially arranged additional layer, or the film material may have a specific structure which eases the suturing process, and which facilitates leak tightness of the suture. In the case that the flat film material is an absorbent material, the preparation may include that an additional component is absorbed by the film material in the region of its longitudinal edges. The additional connecting element, in case that the flat film material is sutured, is a filament or yarn which preferably has properties which are at least approximately identical to the properties of the flat film material, e.g. regarding the flexibility and stretchability. Naturally, also any other suitable additional connecting means may be used for connecting the region of the longitudinal edges of the flat film material, like clips or clamps, preferably made of plastic. Dependent on the number of clips applied to the suture, the size may be selected such that the influence to the properties of the flat film material is reduced to a minimum.

The application of an additional connecting means is advantageously since the established connection may directly be loaded, which means that the tubular casing just produced may immediately be filled with filling material and closed.

It is a further essential idea of the present invention to provide a flat film material which may be equipped with the inventive connecting means, for being formed into a tubular casing.

Dependent on the intended use, like the kind of product to be produced, the tubular casing, e.g. of a sausage-shaped product, which may be made from a flat film material, may be provided with different properties, e.g. regarding its flexibility, stretchability, tightness or permeability under dry and/or wet conditions, and in different temperature ranges. Thus, various base materials may be used for producing a tubular casing, or a flat film material respectively, having defined properties.

Sausage-shaped products may be of very different kind, particular with regard to the filling material, like the kind of sausage meat. Accordingly, said different kinds of sausage-shaped products may be treated in various ways, like dried, smoked or cooked. Thus, the tubular casing, and in particular, the kind of flat film material from which the tubular casing is made, need to be provided with respective different properties. For adjusting specific properties, the flat film material may be made from different base materials which additionally may be treated in various ways during the production of flat film material or thereafter, like applying heat or pressure thereto.

The flat film material may be produced from natural base materials, like cellulose or textiles, or synthetic base materials, like polyamide or polyethylene. Depending on the required properties of the flat film material or the tubular casing, or the kind of connecting means used for forming a tubular casing, a single material or a mix of materials may be used for producing the flat film material.

The flat film material may consist of a single layer having all necessary properties, or of more than one layer, wherein the different necessary properties, like permeability or stretchability, are provided by the different layers.

Moreover, depending on the kind of the connecting means used for forming a tubular casing from the flat film material, the connecting means may be incorporated into the flat film material during the production of the film material, thereafter, or in an intermediate production step, in the case that the flat film material is a single layer material. In the case that the flat film material is a multilayer material, the connecting means may be positioned between two adjacent layers, or in side an intermediate layer which is covered by two layers.

For preventing the layers of a multi-layer flat film material from shifting, said layers are temporarily or permanently connected to each other, e.g. by gluing, welding or calendaring.

Alternatively to the use of a multi-layer flat film material, the different layers may be provided one after the other during the forming of the tubular casing. That means, a first layer, e.g. a water or air permeable layer is formed into a tube by means of a first forming shoulder provided on the filling tube. Thereafter, a second layer is formed into a tube which surrounds the tube formed from the first layer. The second layer may provide the necessary stiffness or stretchability. For forming the second layer into a tube, a second forming shoulder is provided downstream the first forming shoulder. It has to be noted that in such a case, where a first layer is formed into a tube which is subsequently covered by a second tube formed from a second layer, it may be necessary to provide only the second layer or flat film material with the inventive connecting means. It has also to be understood the second or outer layer may be a laminar or a net-shaped film material. In a specific embodiment of a two-layer film material, the inner or first layer is a foodstuff-compatible cellulose material having a defined permeability and the second or outer layer is a plastic net-shaped material having the necessary stretchability and comprises the connecting means, e.g. in the form of weldable portions.

One of the base materials used for the production of flat film material for tubular casings is cellulose.

Cellulose may be the basis for paper-like film material which may be steeped or which may comprise a coating, like viscose, on one side or on both sides.

The connecting means may be applied to the flat film material, and in particular to the region along its longitudinal edges, after a strip of flat film material has been produced. Alternatively, dependent on the kind of the connecting means, e.g. when using a "chemical" connecting means, like an adhesive, the coating may be omitted in the region of the longitudinal edges where the connecting means have to be applied, or the coating is deposited after the connecting means have been applied.

Cellulose may also be processed into non-woven material. During the production process, specific properties may be adjusted, like tear strength, stretchability or shrinkage behavior, e.g. by selecting a specific fiber length or the treatment temperature.

Additionally thereto, the cellulose non-woven may be treated after being produced, like saturated or coated.

Non-wovens may also be produced from synthetic fibers, like polyester, poly ethylene, polyamide and the like, or mixtures thereof.

Non-woven of synthetic fibers may have identical properties like paper, e.g. regarding the flexibility, but a higher resistance against tearing. It is known that flat film material made from polyamide or mixes of synthetic fiber including polyamide has a shrinking behavior, which is of advantage when filling material, like sausage meat reduces its volume, e.g. during a drying process.

Also, film material including cellulose, and tubular casings made thereof, has shrinking properties.

A further advantageous material for the flat film material is a composition of natural and synthetic fibers, like cellulose and polyethylene or the like, in order to combine the properties of the components.

Further alternatively, flat film material may be made from textiles, like silk or cotton, which comprise additional coatings, like collagen coating, to generate specific properties.

Moreover, depending on the mixture of the components of the film material, the connecting means may be applied to the region of the longitudinal edges of the flat film material.

The application of "mechanical" connecting means may be done before or after the flat film material has been produced in a desired width which corresponds to the required diameter of the tubular casing or the diameter of the sausage- shaped product, in an intermediate production step or as the final production step.

In the case that hook and loop fastener are used, the first connecting element which carries the "hook"-elements, and the second connecting element which carries the "loops", are attached to the region of the longitudinal edges of the flat film material such that the first and the second connecting element facing each other when the flat film material is bent into an tube, whereby the longitudinal edges of the flat film material overlap each other. The first and second connecting elements may be glued or welded to the flat film material. Zipper elements may be attached to the flat film material in the same manner, namely glued, welded, like ultra-sonic welding, or by applying heat in any other way thereto.

In the case that particles are used for forming the connecting means, their application depends on the kind and size of the particles.

The substances forming the particles may be provided as a solution or dispersion. In this case, the solution is applied to the flat film material, and particularly, the region of its longitudinal edges. After a drying process, the substance remains in the form of regularly or non-regularly distributed particles on the surface of the flat film material.

One example for connecting means being provided in the form of a solution is polyvinyl alcohol or PVOH which is dissolved e.g. in a sodium hydroxide solution. After drying, PVOH is thermally sealable. It has to be understood that, dependent on the concentration of the solution, PVOH may also form a continuous layer on the flat film material.

As explained above, the particles forming the connecting means, may be incorporated in the film material, e.g. during the production of the film material. In the case that PVOH is selected for forming the particles, PVOH may be dissolved or dispersed in a respective solvent. This solution or dispersion is added to the raw-material for producing the flat film material, like viscose. After a drying process, PVOH forms particles arranged within the film material.

As an alternative, after the production of the flat film material, and prior to a drying process, a solution or dispersion including PVOH, or any other suitable particle forming material, is applied to a portion of said film material, like the region of one or both of the longitudinal edges. Thereafter, the drying process is executed for finishing the film material. Particles in the form of spheres, e.g. of moldable plastic, may be injected into the flat film material by means of a suitable injection apparatus which may include respective needles or the like.

Particles of non-regular shape or with specific features, like magnetism, may be incorporated in the flat film material during its production.

Alternatively, particle, independent from their specific features, may be attached to the surface of the flat film material, by gluing, welding or the like.

When using minerals, like Glimmer, or magnetic components, these elements may also be formed by thin layers extending continuously along the edges of the film material, to which they may be glued or welded or fixed in any other suitable manner.

Further alternatively, the flat film material may be designed as being a two-layer material, at least in the region of the connecting means, i.e. in the region of the longitudinal edges of the flat film material. Accordingly, the connecting means may be positioned between these two layers.

In a further alternative, these second layers applied in the region of the longitudinal edges of the flat film material, form the connecting means, e.g. when made of moldable plastic or a pressure- or temperature-sensitive glue. Such an additional layer may be formed as a small stripe of particularly modified plastic, e.g. acid-modified ethylene copolymer, like maleic anhydride modified poly propylene. It has to be understood that such an additional layer of modified plastic may also be applied to the longitudinal edges of the flat film material immediately before being sealed into a tube.

In the case that the flat film material is formed by a non-woven, which is an absorbent material, the longitudinal edges of this flat film material may be dipped into a connecting means, like molten plastic, a solution or a dispersion of the substances forming the particles which is soaked by the film material, and which solidifies thereafter, e.g. by cooling or drying. The longitudinal edges of the flat film material may be connected to each other by overlapping the edges and activating the connecting means. In order to reduce the thickness of tubular casing in the region of the overlapped portions, the region of the longitudinal edges of the flat film material has a reduced thickness. In the best case, the thickness of the overlapped portions, after being connected, corresponds to the thickness of the remaining film material. That means, the thickness of the region of the longitudinal edges of the flat film material is approximately 50% of the thickness of the remaining flat film material.

For forming the flat film material into a tubular casing, the flat film material is guided to the filling tube of a clipping machine and bent about the filling tube into a tube by a forming shoulder which is positioned on the filling tube. Downstream the forming shoulder, a connecting device is positioned, which permanently or temporarily connects the longitudinal edges of the flat film material.

In the case that the connecting means include a hook and loop fastener, the connecting device comprises at least one pressing tool for pressing the hook elements and the loop elements against each other. Additionally, this specific connecting device may comprise guide means for guiding the hook elements and the loop elements such that they are arranged congruently above each other.

The connecting device for connecting the longitudinal edges of a flat film material, which include magnetic or mineral particles or stripes thereof, includes guide means fur aligning the connecting means to each other. Furthermore, pressing tools may be provided for bringing the connecting elements into closed contact with each other.

In general, pressure tool may also be used for connecting pressure-sensitive connecting means, like pressure sensitive glue. Additionally, the pressure tools may also apply thermal energy to the connecting means for activating thermal- sensitive connecting elements, e.g. for executing e welding process. Naturally, it is also possible that a welding device is provided for executing a welding process, e.g. by applying heat, radiation or ultrasonic waves, for activating the respective connecting means.

Particularly when applying heat, or in the case that the casing material grows warm during the connecting process, a cooling device may be arranged downstream the connecting device, which may use water or air as the coolant.

Moreover, in the case that the longitudinal edges are prepared for being connected by suturing or clipping, the connecting device may be a sewing machine or a clipping machine.

The connecting means explained above, in conjunction with the respective connecting devices also explained above, enable the production of a tubular casing at least approximately just in time, or to produce a small buffer of tubular casing in order to compensate variations in the production speed.

Moreover, the connecting means disclosed above, may operate at least approximately independently from the kind of film material used. That means, by means of the above explained connecting means, nearly all possible kinds of film materials may be processed for nearly any kind of sausage-shaped products.

In particular, the flat film material may be wet film material for forming wet tubular casings, and which is produced from cellulose based material, e.g. for producing raw sausages. Said raw sausages are produced by filling the raw sausage meat under pressure into said wet tubular casing which may be made of fibrous material, whereby the casing material is stretched and the diameter of the tubular casing is enlarged. During smoking and/or drying, the volume of the sausage meat reduces, and while drying, the casing material shrinks, at lest approximately to its former size, for omitting air-bubbles in the sausage meat or inside the tubular the casing.

Additionally, by providing the inventive flat film material including the specific connecting means, any kind of flat film material may be processed, namely formed into a tubular casing which may immediately be filled and closed for forming sausage-shaped products, like a sausages. The flat film material may be prepared in any necessary condition, like dry or wet, depending on the kind of sausage-shaped products to be produced, and the prepared flat film material may be processed immediately after the preparation or may be store in prepared conditions for later processing. Thus, there is no waiting time needed between the preparation of the flat film material, the forming of the tubular casing and the filling process.

Further according to the present invention, there is provided a tubular casing formed by a flat film material having a longitudinal extension, an upper surface, a lower surface, a first longitudinal edge and a second longitudinal edge, the first and second longitudinal edges being aligned at least approximately parallel to each other, wherein the flat film material comprises connecting means arranged at least in the region of one of the first or second longitudinal edge, for connecting the flat film material in the region of the first and second longitudinal edges.

Since nearly any kind of flat film material together with the respective connecting means may be processed for forming a tubular casing just in time, that means without unnecessary time delay between the tube forming process and the filling process, nearly any kind of sausage-shaped products may be produced.

Moreover, the present invention is further directed to a sausage-shaped product, like a sausage, comprising a tubular casing having a first end and a second end, wherein the tubular casing is filled with filling material and closed at its first as well as its second end by a closure means, like a closure clip. The tubular casing is formed by a flat film material having a longitudinal extension, an upper surface, a lower surface, a first longitudinal edge and a second longitudinal edge. The first and second longitudinal edges are aligned at least approximately parallel to each other, and the flat film material comprises connecting means arranged at least in the region of one of the first or second longitudinal edge, for connecting the flat film material in the region of the first and second longitudinal edges. Due to the wide range of properties of the flat film material and the connecting means, a great variety of sausage-shaped products may be produced. Said sausage-shaped products may be sausages or other sausage-shaped packages which include any suitable foodstuff, like butter or cheese, or industrial filling materials, like cleaning paste, explosives, lubricants, silicone or adhesives.

According to the present invention, there is further provided a connecting device for forming a tubular casing from a flat film material, the flat film material having a longitudinal extension, an upper surface, a lower surface, a first longitudinal edge and a second longitudinal edge, wherein the first and second longitudinal edges being aligned at least approximately parallel to each other. The flat film material comprises connecting means arranged at least in the region of one of the first or second longitudinal edge, for connecting the flat film material in the region of the first and second longitudinal edges, the connecting device comprises means for connecting the flat film material in the region of the first and second longitudinal edges.

Depending on the kind of connecting means, different connecting devices may be provided, like a sewing machine, a clipping machine, heat or ultrasonic radiation applying device or pressing tools.

Additionally, said connecting device may be exchanged by another connecting device in order to process various kinds of connecting means applied to different kinds of flat film material.

Further according to the present invention, there is provided a clipping machine for producing sausage-shaped products, like sausages. The clipping machine comprises a filling tube for feeding filling material into the tubular casing stored on the filling tube and being closed at the front end by at least one closure clip, and a closing device for applying and closing the at least one closure clip. The tubular casing is formed by a flat film material having a longitudinal extension, an upper surface, a lower surface, a first longitudinal edge and a second longitudinal edge, the first and second longitudinal edges being aligned at least approximately parallel to each other, the flat film material comprises connecting means arranged at least in the region of one of the first or second longitudinal edge, for connecting the flat film material in the region of the first and second longitudinal edges The inventive clipping machine comprises a connecting device for forming a tubular casing from a flat film material having means for connecting the flat film material in the region of the first and second longitudinal edges.

The clipping machine thereby provides all advantages as explained in conjunction with the flat film material, the tubular casing made from said flat film material, the sausage-shaped product including the tubular casing, and the connecting device for producing a tubular casing, all according to the present invention.

Further advantages and preferred embodiments of the present invention will be described in the following together with the drawings listed below. The expressions "left", "right", "below" and "above" used in the following description, are referred to the drawings in an alignment such that the reference numbers and the notation of the Figs, used can be read in normal orientation.

In the drawings:

Fig. 1 : is a schematically view to a clipping machine for producing sausage- shaped products according to the present invention;

Fig. 2: the general constitution of the flat film material according to the present invention;

Fig. 3: is a schematic and cross sectional view to a tubular casing made from a first group of flat film material according to the present invention;

Fig. 4: is a schematic view to a first embodiment of the first group of flat film material according to the present invention; Fig. 5: is a schematic view to a second embodiment of the first group of flat film material according to the present invention;

Fig. 6: is a schematic and cross sectional view to a tubular casing made from a second group of flat film material according to the present invention;

Fig. 7: is a schematic view to a first embodiment of the second group of flat film material according to the present invention;

Fig. 8: is a schematic view to a second embodiment of the second group of flat film material according to the present invention; and

Fig. 9: is a schematic view to a third embodiment of the second group of flat film material according to the present invention.

Fig. 1 is a schematically view to a clipping machine C for producing sausage- shaped products S according to the present invention.

Clipping machine C comprises as its main components: a filling tube 10 having a first end 12, a second end 14 and a longitudinally extending axis A, a casing break device 20 being arranged at filling tube 10 in the region of its first end 12, a forming shoulder 30 arranged on filling tube 10 and upstream casing brake device 20, and a clipping device 40 being positioned downstream filling tube 10 and immediately in front of first end 12 of filling tube 10. Horizontally arranged filling tube 10 is coupled to filler (not shown) by its second end 14. Clipping machine C further comprises a supply MS of flat film material M stored on a supply roll RS, flat film material M is guided via guide rollers RG to forming shoulder 30. By means of forming shoulder 30, flat film material M is bent into a tube. Furthermore, downstream forming shoulder 30, a connecting device 50 for fixing flat film material M in its tubular shape for forming a tubular casing T is provided. It has to be understood that clipping machine C includes a control unit (not shown) which controls and coordinates the function of the components of clipping machine C, like the time point for activating clipping device 40 or connecting device 50.

In the embodiment according to Fig. 1 , casing brake device 20 is designed as a spreading ring having an inner diameter corresponding to the outer diameter of filling tube 10. The outer diameter of casing brake or spreading ring 20 is selected such that tubular casing T when drawn over spreading ring 20, is unfolded and stretched to a diameter of a defined size which may be larger than the diameter of tubular casing T in unstretched conditions, e.g. about a predefined percentage.

Forming shoulder 30 is designed in the known manner, such that flat film material M may be bent into a tube, in which its longitudinal edges abut against each other, or, if desired, overlay or overlap each other about a defined width. It has to be noted that forming shoulder 30 is adapted for processing flat film material M of a defined width. Thus, in the case that film material M of a different size has to be processed, forming shoulder 30 may be exchanged by a respective other forming shoulder.

Clipping device 40 comprises a first pair 42 of displacer elements 42a, 42b and a second pair 44 of displacer elements 44a, 44b for forming in known manner a plait-like portion P of tubular casing T being at least approximately free of filling material, and a pair closing tools 46 in the form of a punch 46a arranged between displacer elements 42a, 44a above filling tube 10 and a die 46b positioned between displacer elements 42b, 44b below filling tube 10 opposite to punch 46a, provided for attaching at least one closure clip CC to plait-like portion P of tubular casing T.

According to the embodiment of clipping machine C of Fig. 1 , connecting device 50 includes a connecting tool 52 which is arranged immediately downstream forming shoulder 30 and above tubular casing T. Connecting device 50, or at least connecting tool 52, may reversibly be moved towards filling tube 10 and at least approximately vertically thereto, between a working position and a resting position which is shown in Fig. 1 . In the working position, the lowermost surface of connecting tool 52 is in contact with tubular casing T, whereas in the resting position, connecting tool 52, and particularly its lowermost surface, is out of contact with tubular casing T.

It has to be understood that the terms "in contact" and "out of contact" with regard to connecting tool 52 have a functional meaning, whereby "in contact" means not only a direct contact of connecting tool 52 and tubular casing T, e.g. for mechanically acting on tubular casing T, but also a functional contact in which the connecting function is executed, and in which connecting tool 52 not necessarily needs to be in direct contact with tubular casing T, e.g. when heat or radiation is applied for executing the connecting function. Also, when being "out of contact", connecting tool 52, on one hand, may be removed from tubular casing T into a distance with regard to tubular casing T, sufficient for preventing the transmission of any connecting energy thereto, on the other hand, a slight contact may be allowed, e.g. in the case that mechanical connecting means are provided and the slight contact does not transmit sufficient energy for the connecting process. In the latter case, particularly, when no thermal energy is transmitted, a contact of connecting tool 52 and tubular casing T in the resting position may be allowable.

Fig. 2 shows the general constitution of the flat film material M according to the present invention.

Film material M comprises a flat film strip 100 including a first longitudinal edge 102, a second longitudinal edge 104, an upper surface 106 which is visible in Fig. 2, and a lower surface 108 being not visible in Fig. 2. Attachment portions or areas 1 12, 1 14 extend along first longitudinal edge 102 and second longitudinal edge 104 of film strip 100, to which connecting means 200, being explained in greater detail below, are attached, and by means of which longitudinal edges 102, 104 may be connected.

According to Fig. 2, connecting means 200 are attached to both attachment portions 1 12, 1 14. It has to be understood that connecting means 200 may also be attached to one of connecting portions 1 12, 1 14 only, as it is explained in greater detail below, in conjunction with the specific embodiments.

Fig. 3 is a schematic and cross sectional view to a tubular casing T made from a first group of flat film material M according to the present invention. The first group of flat film material M according to the present invention includes connecting means 210 which are attached to only one of the attachment portions 1 12, 1 14 of film strip 100.

As can be inferred from Fig. 3, film strip 100 is bent into a tube with its lower surface 108 facing outwardly, thereby forming the outer side of tubular casing T, and with its upper surface 106 facing inwardly forming the inner surface of tubular casing T. Attachment portions 1 12, 1 14 of film strip 100 overlap each other, and connecting means 200 is positioned between overlapping attachment portions 1 12, 1 14 of film strip 100.

Connecting means 200 is designed as a single-piece connecting means 210 which may be attached to one of the attachment portions 1 12, 1 14 only. When attached to attachment portion 1 12, connecting means 210 are positioned on upper surface 106, whereas, when positioned in attachment portion 1 14, connecting means 210 are positioned on lower surface 108.

In a simple case, as shown in Fig. 3, connecting means 210 may be formed by an adhesive material, or a weldable material, which is arranged on the outer surface of film strip 100, e.g. in the form of a strip covering one of attachment portions 1 12, 1 14.

One example of a weldable material forming connecting means 210 is a strip of modified plastic, like maleic anhydrite modified poly propylene, which is applied to one of attachment portions 1 12, 1 14. Such modified plastics have high affinity to non-woven materials, like cellulose fiber materials, and provide good results in sealing cellulose fiber materials as the flat film material M into tubular casing T. Alternatively, connecting means 210 may also be applied to one of attachment portions 1 12, 1 14 in the form of a solution including the connecting means in dissolved state.

One example for connecting means being provided in form of a solution is polyvinyl alcohol or PVOH which is dissolved e.g. in a sodium hydroxide solution. After drying, PVOH is thermally sealable. It has to be understood that, dependent on the concentration of the solution, PVOH may also form a continuous layer on the flat film material.

Additionally to the sealing properties, PVOH is insensible to glycerin that is used as a softener in the production of elastic materials. Furthermore, glycerin may support the integration and cross-linking of PVOH, whereby the properties of the sealing connection are enhanced, like water resistance.

Fig. 4 is a schematic view to a first embodiment of the first group of flat film material M according to the present invention, which includes connecting means 200 which is designed as a single-piece connecting means 210 attached to only one of attachment portions 1 12, 1 14. Accordingly, only one attachment portion, exemplarily attachment portion 1 12, is shown.

Single-piece connecting means 210 according to the specific embodiment of Fig. 4, is not arranged on one of the outer surfaces 106, 108 of film strip 100, but inside filmstrip 100, and in particular, inside attachment portion 1 12.

Single-piece connecting means 210 according to Fig. 4 include a number of particles 212 which are arranged inside attachment portion 1 12 and, at least approximately below upper surface 106 of film strip 100.

Particles 1 12 may consist of any suitable material by means of which a connection between attachment portion 1 12 and attachment portion 1 14 when overlapping attachment portion 1 12, may be reached. Particles 212 may consist of a material that becomes liquid under the impact of energy, like heat, radiation or pressure. Particles 212, accordingly may be made of plastics or the like, which may be welded or sealed.

As it further can be seen in Fig. 4, particles 212 are arrange side by side in two rows parallel to upper surface 106 of film strip 100, and in regular intervals. Naturally, particles 212 may have any other arrangement and any suitable number of rows, like three ore more rows, and arranged offset to each other for forming a kind of labyrinth for enhancing the tightness of tubular casing T, with a minimum influence of the single-piece connecting means 210 to the properties of film strip 100.

According to Fig. 4, particles 212 are arranged in regular intervals. It is also possible that particles 212 are non-regularly arranged.

In one specific embodiment, film strip 100 is made from a non-woven, like cellulose fiber material. In this case, the connecting means or particles 212 are provided in the form of a solution, like polyvinyl alcohol or PVOH which is dissolved e.g. in a sodium hydroxide solution. The solution is provided to attachment portion 1 12 and soaked by the non-woven film material. After drying, PVOH forms particles in attachment portion 1 12 of film strip 100. Depending on the concentration and the kind of application of the solution, PVOH forms particles 212 which are arranged regularly or non-regularly.

Fig. 5 is a schematic view to a second embodiment of the first group of flat film material M according to the present invention, including single-piece connecting means 210.

In this embodiment, single-piece connecting means 210 are arranged in attachment portion 1 12, and provided in the form of a stripe 214 having a width corresponding to the width of attachment portion 1 12 of film strip 100.

Stripe 214 is arranged within attachment portion 1 12, parallel and closed to upper surface 106 of film strip 100. Film strip 100 according to the embodiment of Fig. 5, is designed as a two-layer strip in the region of attachment portion 1 12. Attachment portion 1 12 is of a reduced thickness, particularly, a portion of strip material corresponding to the width of attachment portion 1 12, has been left at upper side 106, what may be done during the production of film strip 100 or in a production step thereafter. In this clearance, stripe 214 forming the connecting means has been placed, and subsequently, stripe 214 has been covered by a layer 1 16 for filling the remaining clearance.

Stripe 214 may be of any suitable material being weldable or sealable by applying energy, like heat, radiation or pressure, thereto. Layer 1 16, in one specific embodiment, is made from permeable material, such that the material of stripe 214 when treated with energy, may liquefy and may be soaked by layer 1 16 to come in contact with attachment portion 1 14 in order to establish a connection between connecting portions 1 12, 1 14 of film strip 100 for forming tubular casing T.

It is also possible that layer 1 16 is only a covering layer which is removed immediately before connecting connection portions 1 12, 1 14 of film strip 100. Accordingly, layer 1 16 does not need to have a thickness to fill the clearance in attachment portion 1 12. Additionally, also attachment portion 1 14 may have reduced thickness, with a respective clearance facing to the clearance in connecting portion 1 12, such that the overall thickness of the joint of tubular casing T formed by connecting portions 1 12, 1 14 is at least approximately equal to the thickness of film strip 100.

Fig. 6 is a schematic and cross-sectional view to a tubular casing T made from a second group of flat film material M according to the present invention. The second group of flat film material M according to the present invention includes connecting means 200 which are attached to both attachment portions 1 12, 1 14 of film strip 100. That means connecting means 200 is designed as a two-piece connecting means 220, which includes two connecting elements with a first connecting element attached to attachment portion 1 14, and second connecting element attached to attachment portion 1 14 of film strip 100. As it can be inferred from Fig. 6, film strip 100 is bent into a tube with its lower surface 108 facing outwardly, thereby forming the outer side of tubular casing T, and with its upper surface 106 facing inwardly forming the inner surface of tubular casing T. Attachment portions 1 12, 1 14 of film strip 100 overlap each other, and two-piece connecting means 220 is positioned between overlapping attachment portions 1 12, 1 14 of film strip 100.

In a simple case, as shown in Fig. 6, the two connecting elements of two-piece connecting means 220 may be formed by an adhesive material, or a weldable material, and be arranged at connecting portion 1 12 on upper side 106 of film strip 100 and at connecting portion 1 14 on lower side 108 of film strip 100. It has to be understood that connecting means 220 may be of that kind explained in conjunction with Fig. 3 above.

Fig. 7 is a schematic view to a first embodiment of the second group of flat film material M according to the present invention, including two-piece connecting means 220.

Two-piece connecting means 220 according to Fig. 7 includes a first connecting element 222 arranged at attachment portion 1 12 on upper side 106 of film strip 100, and a second connecting element 224 arranged at attachment portion 1 14 on lower side 108 of film strip 100.

First connecting element 222 comprises two flanges 222a, 222b which extend along longitudinal edge 102 of film strip 100 at attachment portion 1 12, and which are arrange parallel to each other with an offset there between.

Second connecting element 224 comprises three flanges 224a, 224b, 224c which extend along longitudinal edge 104 of film strip 100 at attachment portion 1 14, and which are arrange parallel to each other with an offset there between.

The offset or distance between flanges 224a, 224b, 224c of second connecting element 224 corresponds to the width of flanges 222a, 222b of first connecting element 222, and at least the width of flange 224b of second connecting element 224 corresponds to the offset between flanges 222a, 222b. This design enables flanges 222a, 222b to engage into the grooves formed between flanges 224a, 224b, 224c in order to establish a form-fit connection between connection portions 1 12, 1 14 of film strip 100.

It has to be noted that flanges 222a, 222b and 224a, 224b, 224c may be provided with additional elements arranged along their edges, like hooks, grooves or lips, for improving the positive locking between these elements. Thereby a kind of zip- lock may be realized, which enabled a permanent or temporary connection of connection portions 1 12, 1 14, which may also be re-opened, e.g. for removing tubular casing T.

Alternatively, flanges 222a, 222b and 224a, 224b, 224c may also consist of a sealable material, which e.g. may be fused for establishing a permanent connection between connection portions 1 12, 1 14 of film strip 100.

In this embodiment, first and second connecting elements 222, 224 also function as guide means for correctly position connection portions 1 12, 1 14 of film strip 100 above each other.

Furthermore, this specific kind of connecting means 220 is not limited to the described number of flanges or their specific design. It is also possible that at one of the connecting portions 1 12, 14 only one flange 222 is arranged, and two flanges 224 are positioned at the respective other connecting portion 1 14, 1 12. Also more than two or three flanges may be provided, e.g. in order to enhance the stability or security of the closure.

Fig. 8 is a schematic view to a second embodiment of the second group of flat film material M according to the present invention, which includes two-piece connecting means 220.

As can be seen in Fig. 8, two-piece connecting means 220 include particles 226 arranged in both connecting portions 1 12, 1 14 of film strip 100, which means within the strip material of connecting portions 1 12, 1 14, as already explained in conjunction with single connecting means 210 according to the embodiment of Fig. 4.

Particles 226 in connecting portions 1 12, 1 14 are positioned such that they are arranged opposite to each other when connecting portions 1 12, 1 14 are overlapped for being connected.

Particles 226 are arrange side by side in two rows parallel to upper surface 106 of connecting portion 1 12 of film strip 100 and to lower surface 108 of connecting portion 1 14 of film strip 100, and in regular intervals. Alternatively, particles 226 may have any other arrangement and any suitable number of rows, like three ore more rows, and arranged offset to each other for forming a kind of labyrinth for enhancing the tightness of tubular casing T, with a minimum influence of two- piece connecting means 220 to the properties of film strip 100.

As it further can be inferred from Fig. 8, the thickness of connecting portions 1 12, 1 14 is reduced in relation to the remaining portion of film strip 100. Namely, a first clearance has been formed into upper side 106 extending over the entire surface of connecting portion 1 12, and a second clearance has been formed into lower side 108 of film strip 100, which extends over the entire surface of connecting portion 1 14.

Furthermore, form-fitting means 230 are provided, whereby the surface of connecting portion 1 12 facing towards connecting portion 1 14, is provided with a recess 232 having an at least approximately rectangular shape, and the surface of connecting portion 1 14 includes a protrusion 234 having a shape corresponding to the shape of recess 232. By forming recess 323, the width of which is smaller than the width of connecting portion 1 12, on both sides of recess 232, protrusions 232a, 232b have been created. In the same manner, while forming protrusion 234 in connecting portion 1 14, on both sides of protrusion 234, recesses 234a, 234b are generated, the size of which corresponds to the size of protrusions 232a, 232b. When forming flat film material M according to the embodiment of Fig. 8 into a tubular casing T by overlapping connecting portions 1 12, 1 14, protrusions 234, 232a, 232b engage recesses 232, 234a, 234b, whereby, additionally to the force fit connection by activating connecting means 220, also a form-fit connection is established. By providing both, a form-fit connection and a force-fit connection, each of the connecting means may be reduced to a minimum, at least in relation to the use of only one of this connecting means. Accordingly, the influence of the connection between connecting portions 1 12, 1 14, particularly with regard to the properties of film strip 100 may be reduced, and the connection or seam and film strip 100 may have approximately identical properties, e.g. regarding the stretchability, permeability or the like.

It has to be understood that the combination of form-fit connecting means and force-fit connecting means is not limited to the embodiment as shown in FIG. 8. Such a combination may be provided to any other embodiment, which e.g. include single-piece connecting means or two-piece connecting means, and in which connecting portions 1 12, 1 14 are overlapped to be connected.

Fig. 9 is a schematic view to a third embodiment of the second group of flat film material M according to the present invention which includes two-piece connecting means 220.

In contrast to the embodiments of flat film material M according to the embodiments of Figs. 7 and 8, in the embodiment according to Fig. 9, tubular casing T is formed by abutting longitudinal edges 102, 104 of film strip 100 against each other, and activating two-piece connecting means 220.

Two-piece connecting means 220 according to Fig. 9, include particles 226 as already known from the embodiments according to Figs. 4 and 8. Particles 226 are placed within connecting portions 1 12, 1 14, and in closed vicinity to longitudinal edges 102, 104 of film strip 100.

When abutting longitudinal edges 102, 104 of film strip 100, and activating connecting means 220, particles 226 may liquefy under the impact of energy, like heat, radiation or pressure, and the liquefied material of particles 226 may saturate the region of both longitudinal edges 102, 104. While solidifying, a connection between connecting portions 1 12, 1 14 is established, without increasing the thickness of the connection region.

In alternative embodiments, it is possible to arrange particles 226 in only one of connecting portions 1 12, 1 14 of film strip 100 for forming single-piece connecting means 210, or to replace particles 226 by a stripe arranged within one or both of connecting portions 1 12, 1 14, as explained in conjunction with the embodiment according to Fig. 5.

In alternative embodiments, particles 212, 226 or stripe 214 may be made of other than sealable materials which are activated by applying energy, like heat, radiation or pressure, thereto. Particles or stripes may consist of any suitable material such that adhesive forces act between two adjacent particles or stripes being sufficient for establishing a temporary or permanent connection of connecting portions 1 12, 1 14 for forming a tubular casing T, like magnetic forces, inter-crystalline or inter-atomic forces.

For forming a tubular casing T, from a supply MS of flat film material M stored on a supply roll RS, flat film material M is guided via guide rollers RG to forming shoulder 30 of clipping machine C, which is arranged on filling tube 10 of clipping machine C. While passing forming shoulder 30, flat film material M is bent into a tube, whereby longitudinal edges 102, 104 of filmstrip 100 of flat film material M are positioned closed to each other. Dependent on the kind of connecting means 210, 220, longitudinal edges 102, 104 abut each other, or connecting portions 1 12, 1 14 of filmstrip 100 overlap each other.

Thereafter, connecting tool 52 of connecting device 50 is activated. That means, connecting tool 52 is moved towards connecting portions 1 12, 1 14 for activating connecting means 200.

In the case that connecting means 200 are activated by applying heat thereto, or in the case that connecting means 200 are heated by applying radiation thereto, a cooling device which is positioned immediately downstream connecting device 50, is activated for solidification of the liquefied connecting means, or at least for cooling the seam.

Tubular casing T which is closed at its front end by a closure clip CC, is pulled-off from filling tube 10 in the known manner, namely by the pressure of the filling material fed through filling tube 10. After a predetermined volume or mass of filling material has been fed into tubular casing T, gathering means 42, 44 gather the filled tubular casing T and forming a plate-like portion P thereto. Thereafter, clipping tools 46 place and close at least one, preferably two, closure clips CC to the plait-like portion P. Also in the known manner, a suspension element, like a suspension loop, may be coupled to the plait-like portion P, e.g. by means of the closure clip CC which closes the just filled portion of tubular casing T for producing a sausage-shaped product S, like a sausage.

During the filling process, tubular casing T is, at least approximately, continuously pulled off from filling tube 10 by the pressure of the filling material fed through filling tube 10, whereby additional tubular casing T is formed by bending flat film material M into a tube and connecting the connecting portions 1 12, 1 14 by means of connecting device 50.

Clipping machine C includes a control unit, which not only controls the flow of the filling material, but also controls the operation of connecting device 50. During the continuous pull-off of tubular casing T, additional tubular casing T is formed by connecting device 50, which, in this time, also continuously operates.

In case that the production process is interrupted or the production speed is lowered, also the operation of connecting device 50 may be interrupted by the control unit. Alternatively, connecting device 50 may be controlled such that a supply of tubular casing T is produced and stored on filling tube 10, particularly between connecting device 50 and casing break device 20, e.g. for leveling reductions in the speed of the production process, like the closing phases in which the filled tubular casing T is gathered and closed, and in which the flow of filling material may be reduced. In this case, an additional device may be provided, which pulls flat film material M over forming shoulder 30, particular in that times when no filling pressure is applied for pull-off of tubular casing T from filling tube 10.