Heat-welded welding jaws and method

Abstract

The present invention relates to a welding jaw for heat-welding a pouch wall (1) formed from a plastic film to a welding region (2) of a spout (3) formed from plastic, comprising a jaw body (4) connectable to a heat source, wherein the jaw body (4) has a pressing surface (5), and the pressing surface (5) can press the pouch wall (1) toward the welding region (2) of the spout (3) in the surface region (1a) to be welded, and a pressing element (6) is disposed on the jaw body (4). The present invention relates to a welding jaw, in particular to a jaw body (4), wherein the pressing element (6) has a second pressing surface (7) located adjacent to the first pressing surface (5) of the pressing jaw (4), and the second pressing surface (7) is capable of pressing the pouch wall (1) in a direction toward the welding area (2) of the spout (3) or the central longitudinal axis (12) of the spout passage in a non-welding area (1b) located adjacent to the area to be welded (1a). The present invention further relates to a method for heat welding a pouch wall (1) formed from a plastic film to a welding area (2) of a spout (3) formed from plastic.

Description

Technical Field

[0001] The present invention relates to a welding jaw for thermally welding the wall of a pouch formed from a plastic film to a welding area of a spout formed from plastic, the welding jaw including a jaw body that can be coupled to a heating source, the jaw body having a pressing surface by which the wall of the pouch can be pressed toward the welding area of the spout in the surface area where the wall is to be welded.

Background Art

[0002] In particular, the pressing surface of the jaw body can be indirectly heated by a heating source, preferably based on the thermal conductivity of the jaw body formed from metal, until it reaches a temperature exceeding the melting temperature of the materials of the wall and the welding area.

[0003] By pressing the wall toward the welding area using the heated pressing surface, the wall and the welding area are heated until they exceed the respective melting temperatures of the wall and the welding area, so that these two members are joined in a material-bonded manner at their facing surfaces under the action of the applied welding pressure.

[0004] The present invention relates to a method for thermally welding the wall of a pouch formed from a plastic film to a welding area of a spout formed from plastic, the method comprising causing two welding jaws located on opposite sides to approach the welding area in opposite directions, the welding jaws each having one jaw body coupled to a heating source, each jaw body having a pressing surface by which the wall of the pouch located between the pressing surface and the welding area is pressed toward the welding area of the spout in the surface area where the wall is to be welded.

[0005] In the prior art, pouch packaging, particularly so-called squeeze pouches, is known. In pouch packaging, a spout is welded between two wall regions located on opposite sides of the pouch, allowing the contents of the pouch to be removed through the spout passage. Preferably, each wall is formed from multiple film layers.

[0006] Such a spout, in the prior art and preferably in the present invention, includes a spout passage, the passage wall of the spout passage being formed as a spout tube in a first end region, the passage wall being surrounded in a second end region by a welded region, the welded region having two welded arms, these welded arms extending to their respective ends in opposite directions perpendicular to the passage axis of the spout passage, and particularly extending away from the passage wall in the second end region, each welded arm having a welded zone, for example, a plurality of rib elements, these rib elements being coupled to the passage wall in the second end region and preferably spaced apart from each other in the direction of the passage axis, the first welded side having a first welded zone extending between the passage wall and the end of the welded arm, and the second welded side having a second welded zone extending between the passage wall and the end of the welded arm. In this case, the first and second welding zones converge toward the end of the welding arm. In a possible configuration, these welding zones may extend at least partially in a straight or flat manner. In such a case, the regions extending linearly from the first and second welding zones form an acute angle between them. However, the welding zones may be configured to be curved.

[0007] Such spouts are commonly known in the prior art, for example, as disclosed in Patent Document 1 of the same applicant. The spout is defined to be welded between two walls, for example, a film layer, of a pouch containing, for example, food products, particularly liquid food products, especially a film pouch. Due to the convergence of the weld zones in both weld arms, the weld region has a shape that tapers in the direction from the passage axis toward the end of the weld arm, and is in particular often called a boat-shaped section. This taper occurs in a plane perpendicular to the passage axis.

[0008] Welding is performed between the welding zone and the respective walls on each of the two welding sides, using welding jaws that apply welding energy from two opposing welding sides through the respective walls of the pouch to the welding zone of the welding area.

[0009] Therefore, the welded sides are the two sides located opposite each other in the welded region. The welded sides are located on both sides within a single plane that includes the passage axis and both ends of the welded arms. Here, the passage axis is the longitudinal extension axis of the spout passage extending through the spout.

[0010] This plane can also be called the front plane and coincides with a plane that is parallel to the walls of the pouch, especially an unfilled pouch.

[0011] When the pouch is upright during use, one end region that forms the upper end region in its function as a spout tube section is generally fitted with a removable closure, such as a cap. This cap is preferably attached to a threaded connection provided on the spout tube section, or is attachable and removable.

[0012] The second end region that forms the welding area is the lower end region of the spout during the aforementioned use. The present invention preferably relates to the use of the method according to the present invention on such a spout and to the use of such a spout in relation to the welding jaw according to the present invention.

[0013] When a welding jaw is used on the welding area of ​​such a spout, the heated pressing surface of the welding jaw comes into contact with the wall, heating the wall. Furthermore, the wall is moved closer to the welding area of ​​the spout by the movement of the welding jaw. This causes the heated surface area of ​​the wall to move relative to the unheated surface area, resulting in the extension of the heated surface area at the transition to the unheated and unwelded surface area of ​​the wall. This leads to a lack of airtightness in the wall after welding. Therefore, such airtightness can mainly occur in the unwelded surface area of ​​the wall that is directly adjacent to the welded surface area. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] German Patent Application Publication No. 102017009693 Specification [Overview of the project] [Problems that the invention aims to solve]

[0015] Against this backdrop, the object of the present invention is to improve the type of welding jaw and method described at the beginning of the invention, which involves heat welding, in order to reduce, preferably eliminate, the stretching of the wall in the transition region between the welded surface area and the unwelded surface area of ​​the wall, thereby reducing, preferably eliminating, the risk of non-sealing. [Means for solving the problem]

[0016] This problem is solved by the welding jaw of the type described at the beginning, in which a pressing element is arranged on the jaw body, and in particular is attached to the jaw body, and the pressing element has a second pressing surface located adjacent to the first pressing surface of the jaw body, and the second pressing surface allows the wall of the pouch to be pressed in a direction toward the welding area of ​​the spout in a non-welding area located adjacent to the area to be welded.

[0017] During the operation of the welding jaws as specified, that is, especially when the welding jaws are being moved toward the welding area of ​​the spout, the surface of the welding jaws that can exert force on the pouch wall is called the pressing surface, which allows the area of ​​the wall in contact with each pressing surface to move toward the welding area of ​​the spout.

[0018] This problem is solved in the type of method described at the beginning, in which a pressing element is arranged on the jaw body, and in particular is attached to the jaw body, and the pressing element has a second pressing surface located adjacent to the first pressing surface of the jaw body, and the second pressing surface presses the wall of the pouch in a direction toward the welding area of ​​the spout, in a non-welding area located adjacent to the area to be welded.

[0019] Pressing the wall in the direction toward the welding area of ​​the spout in the area of ​​the surface that should not be welded is understood to mean that the second pressing surface pushes the wall, at least in the area outside the area of ​​the surface to be welded, particularly toward the central plane, thereby reducing the distance of the wall, at least outside the area of ​​the surface to be welded, from the welding area. Here, the spout is positioned to surround an intermediate plane, which includes the central longitudinal axis extending through the spout passage of the spout. This does not suggest that this surface area reaches a position directly opposite the welding area. Only the surface area of ​​the wall to be welded reaches a position directly opposite the welding area until it contacts the welding area.

[0020] The surface area located outside the surface area to be welded on the wall / adjacent to the surface area to be welded on the wall, that is, the surface area that should not be welded to the welding area, is preferably below the welding area in the axial direction of the extension of the spout passage of the spout, on the side of the welding area opposite to the spout passage, and / or adjacent to the welding area in the radial direction with respect to the extension direction of the spout passage, particularly outside the radius of the end portion located outside the radius of the welding arm that tapers outward in the radial direction of the welding area.

[0021] That is, according to the present invention, different from the prior art, the welding jaw does not only contact the surface area to be welded on the wall, but also contacts the surface area that should not be welded, and being pushed forward during movement is achieved. Thereby, relative movement between the surface area to be welded and the surface area that should not be welded is prevented. In particular, these surface areas are not bent, and furthermore, stretching of the heated surface area at the transition to the surface area that should not be welded is avoided. Therefore, the above-mentioned drawbacks are overcome.

[0022] Preferably, the method according to the present invention keeps the second pressing surface at a temperature lower than the temperature of the first pressing surface. In particular, while keeping the second pressing surface from exceeding the melting temperature of the material to be welded on the wall and the welding area, it is defined that the temperature of the first pressing surface exceeds the melting temperature of the wall and the welding area.

[0023] This can generally be achieved by the pressing element being cooled and / or being heated less than at least the jaw body.

[0024] For this purpose, the present invention can define that, for example, the pressing element or at least the second pressing surface is formed from a material having a lower thermal conductivity than the material of the jaw body.

[0025] As a result, even when the second pressing surface is indirectly heated by the heating element through the joe body, it is achieved that the second pressing surface reaches a lower temperature than the first pressing surface. This is because a relatively small heat flow reaches the second pressing surface, and preferably this second pressing surface is farther away from the heat source than the first pressing surface. Preferably, the pressing element or at least the second pressing surface of the pressing element is formed from silicone. This material is thermally stable with respect to the normal melting temperature of plastics and has a lower thermal conductivity than the material of the joe body, for example when the joe body is preferably manufactured from metal.

[0026] Alternatively or additionally to the above-described configuration, it may be defined that the pressing element is indirectly attached to the joe body via at least one heat insulating element, and that the insulating element is formed from a material having a lower thermal conductivity than the material of the joe body.

[0027] Also by means of the heat insulating element, it is possible to achieve that the second pressing surface is kept at a lower temperature compared to the temperature of the first pressing surface, even when the second pressing surface is indirectly heated by the heating element through the joe body. This is because a relatively small heat flow reaches the pressing element or the second pressing surface through the heat insulating element, and preferably the pressing element or the second pressing surface is farther away from the heat source than the first pressing surface. When using the heat insulating element, the pressing element does not necessarily have to have a lower thermal conductivity than the joe body, i.e., for example, it may be manufactured from metal. However, also preferably in this case, it is defined that the thermal conductivity of the pressing element is lower than the thermal conductivity of the joe body, and preferably the pressing element is formed from silicone.

[0028] In all possible configurations of this invention, preferably, a gap is formed between the first and second pressing surfaces in the welding jaw, and in particular, within this gap, the pouch wall does not come into contact with the welding jaw. Thus, heat transfer to the wall is avoided in this region, but the wall moves on both sides of this region due to the welding jaw and both pressing surfaces, which prevents tension.

[0029] Preferably, the gap is formed by a spacer element positioned between the jaw body and the pressing element, having a surface area recessed behind the first and second pressing surfaces. Such a spacer element can simultaneously form the aforementioned heat insulating element. Alternatively, the gap may be formed by at least one of the opposing edges of the first and second pressing surfaces being formed with a chamfered or rounded portion.

[0030] The present invention may also specify that, in all possible configurations, the spacer element and / or thermal insulation element is preferably formed of a material containing heat-resistant fibers, particularly glass fibers. Here, heat resistance means, in particular, that the material can withstand the temperature present in the jaw body without being damaged.

[0031] Furthermore, in all possible configurations, preferably the pressing element is positioned between two retaining plates, and preferably the retaining plate located between the pressing element and the jaw body may form the aforementioned insulating element and / or spacer element.

[0032] Therefore, for example, a pressing element, particularly one formed from silicone, may be positioned between two retaining plates and attached to the jaw body via an insulating element on the side facing the jaw body. Thus, the retaining plates preferably provide the necessary stability for the flexible pressing element.

[0033] In general, the pressing element may be attached directly to the jaw body, or indirectly via one of the aforementioned elements (insulating element, spacer element, retaining plate), for example, by screw fastening.

[0034] In all possible configurations, the first pressing surface is formed between two surfaces of the jaw body that are opposite to each other in the thickness direction of the jaw body, and the second pressing surface is formed between two surfaces of the pressing element that are opposite to each other in the thickness direction of the pressing element, and the two surfaces of the jaw body that are opposite to each other and the two surfaces of the pressing element that are opposite to each other are located in a plane parallel to each other. In this case, preferably, the first pressing surface and / or the second pressing surface may be formed flat in the thickness direction, at least in the main surface area.

[0035] In particular, the second pressing surface used for welding is formed by a sub-region of a surface that joins both surfaces, which are located opposite each other, in a direction perpendicular to the surfaces.

[0036] In this configuration, the second pressing surface is located next to the spout welding area and on the side of the welding area opposite the spout passage; that is, facing the surface area of ​​the pouch wall located below the welding area when the spout passage is oriented vertically.

[0037] The pressing element, and by extension the pressing surface of the pressing element, may be attached to the jaw body, while the second pressing surface may be attached to the surface area of ​​the pouch wall located radially adjacent to the end / tip of the welding arm mentioned at the beginning. The present invention allows the pressing element to be provided simultaneously on a single welding jaw in both configurations.

[0038] It is particularly preferable that the first pressing surface and / or the second pressing surface are formed in a concave shape, especially when viewed in a direction perpendicular to the thickness direction or in a cross-section parallel to one of the surfaces located opposite each other.

[0039] In such cases, the welding region is preferably surrounded by the first pressing surface in a predetermined area, particularly on one side of the central longitudinal axis of the spout passage, and preferably over a range of at least 170 degrees around the central longitudinal axis. Thus, the welding region is surrounded on both sides by two welding jaws located on opposite sides of each other, after these welding jaws are brought closer together.

[0040] In this configuration, preferably, the first pressing surface and / or the second pressing surface may be defined as being concave, each pressing surface comprising two sub-surfaces, in particular two flat sub-surfaces, where these two sub-surfaces form an angle between them greater than 90 degrees, preferably greater than 100 degrees, and where these two sub-surfaces transition particularly continuously to each other in the transition region, preferably being rounded.

[0041] The flat portion surface is preferably located in a plane parallel to the central longitudinal axis of the spout passage.

[0042] In a suitable combination of the spout and welding jaws, the angle at which the welding arm tapers in the welding region and the angle formed between the partial surfaces of the first pressing surface are matched to each other, so that complete contact is possible between the partial surface and the welding zone provided on the welding arm in the welding region. Preferably, the angle formed between the partial surfaces is equal to 180 degrees minus the taper angle of the welding arm.

[0043] Preferably, the present invention can specify that the second pressing surface moves in a predetermined region to precede and / or lag behind the first pressing surface, and in particular, when the pressing surfaces extend symmetrically from the inside out, the outer surface region of the second pressing surface moves to precede the outer surface region of the first pressing surface, and the inner surface region of the second pressing surface moves to lag behind the inner surface region of the first pressing surface.

[0044] Particularly for this reason, or for other reasons, the present invention may preferably specify that the angle formed between the partial surfaces of the second pressing surface is smaller than the angle formed between the partial surfaces of the first pressing surface.

[0045] More preferably, in order to achieve the aforementioned trailing / leading configuration, the first and second pressing surfaces each form a concave notch, particularly when viewed in a cross-section parallel to the surfaces located opposite each other, in which case each notch has a notch bottom, the notch bottom being surrounded by two notch edges located opposite each other, and the notch bottoms and / or notch edges of both pressing surfaces are positioned so as not to align with each other or offset from each other, particularly when viewed in a predetermined direction of movement of the welding jaws as specified during welding.

[0046] The bottom of the notch preferably includes or is a region where the partial surfaces transition to each other. The edge of the notch preferably is the pressing surface or the region where both partial surfaces of the pressing surface rise upward from the bottom of the notch.

[0047] Preferably, the notch edge of the second pressing surface protrudes beyond the notch edge of the first pressing surface, particularly in the direction toward the welding area, and / or the notch bottom of the second pressing surface is recessed behind the notch bottom of the first pressing surface, particularly with respect to the direction of motion of the welding jaw toward the welding area.

[0048] It is even more preferable that the notched edge of the second pressing surface forms a flat portion that extends longer than the notched edge of the first pressing surface, particularly when viewed in the direction of separation of the notched edges, and that the second pressing surface extends outward beyond the first pressing surface.

[0049] Here, "outward" means from the bottom of the notch beyond the edge of the notch. Each pressing surface preferably extends from the bottom of the notch through the partial surface to the highest point of the notch edge, and especially until the notch edge descends outward again. Thus, the notch edge of the second pressing surface descends more slowly outward than the notch edge of the first pressing surface.

[0050] It is even more preferable that the concave first pressing surface and / or the concave second pressing surface are formed symmetrically around a central plane that is particularly parallel to the thickness direction.

[0051] The drawings illustrate the present invention in comparison with the prior art. Figures 1 and 2 show the prior art, while Figures 3 to 6 show embodiments of the present invention. [Brief explanation of the drawing]

[0052] [Figure 1] This is a diagram showing the conventional technology. [Figure 2] This is a diagram showing the conventional technology. [Figure 3] This figure shows an embodiment of the present invention. [Figure 4] This figure shows an embodiment of the present invention. [Figure 5] This figure shows an embodiment of the present invention. [Figure 6] This figure shows an embodiment of the present invention. [Modes for carrying out the invention]

[0053] Figure 1 schematically shows the initial stage of thermal welding between the pouch wall 1 and the welding region 2 of the spout 3, where the spout 3 has a spout passage in the upper region that is closed by a cap. The spout passage extends around the central longitudinal axis 12, and below / below the cap, the spout passage transitions into the welding region 2. Figure 1B shows that the welding region 2 may be called a boat-shaped section, which is a common designation in the art. The welding region is formed by two welding arms, as is known and also in the present invention. These welding arms extend radially outward in the opposite direction from the central longitudinal axis 12, and taper outward from the central longitudinal axis, particularly tapering in a plane perpendicular to the central longitudinal axis 12. The surfaces of the radially outward-facing welding arms form the welding surface of the welding region. The wall is welded to this welding surface.

[0054] Figures 1A and 1B show the initial positions of the jaw bodies 4 of the welding jaws that can be heated by the heating element 14, from different line of sight directions, but only one of the two jaw bodies 4 is shown here. The two jaw bodies 4 are located opposite each other around the central longitudinal axis and are preferably moved toward the central longitudinal axis 12 or toward the welding region 2 in the direction of the illustrated arrows, pressing the pouch wall 1 toward the welding region 2.

[0055] In this case, the surface area 1a of the wall to be welded comes into contact with the pressing surface 5 of the jaw body 4 and is heated. The arrangement of the welding jaw / jaw body 4 and the wall 1 relative to the spout 3 is mirror-symmetric with respect to the central longitudinal axis 12 and the plane in which the tip of the welding arm is located, both in the prior art and in the present invention.

[0056] Here, in Figures 1A and 1B, it can be seen that the surface area 1b of the wall that is not to be welded, which is adjacent to, and in particular directly adjacent to, the surface area 1a to be welded, is not in contact with the pressing surface 5 of the jaw body 4, nor is it in contact with any other element that guides this surface area.

[0057] Figures 2A and 2B illustrate the resulting problems, namely, the strong relative motion between the two surface regions 1a and 1b. This is because only the region to be welded is pressed toward the welding region 2 or the central longitudinal axis 12, while the region 1b adjacent to the region to be welded and not to be welded is not pressed, and therefore this region 1b lags behind the movement. Consequently, the heated surface region 1a to be welded is stretched and weakened at the transition to the surface region 1b that is not to be welded. This leads to non-sealing in the pouches produced in the regions circled in Figures 2A and 2B, respectively.

[0058] The present invention addresses the problems shown in Figures 1 and 2 by having a pressing element 6 positioned on the jaw body 4, particularly attached to the jaw body 4 by, for example, screw fastening, and having a second pressing surface 7 positioned adjacent to the first pressing surface 5 of the jaw body 4, and by this second pressing surface 7 being able to press the pouch wall 1 in the direction toward the welding area 2 of the spout 3 or the central longitudinal axis 12 of the spout passage, in the non-welding area 1b positioned adjacent to the surface area 1a to be welded.

[0059] Figures 3A and 3B show the initial position of the jaw body 4 in the present invention in comparison with the initial position of the prior art shown in Figures 1A and 1B, and Figures 4A and 4B show the final position of the jaw body 4 in the present invention in comparison with the final position of the prior art shown in Figures 2A and 2B.

[0060] Here, it can be seen that the second pressing surface 7, provided by the pressing element 6 and acting on the surface area 1b that is not to be welded, which is adjacent to the area 1a to be welded, and in particular directly adjacent to it, ensures that no relative movement occurs between surface area 1a and surface area 1b, or that the relative movement is not too strong. As a result, the stretching and weakening of the heated surface area 1a at the transition to surface area 1b is reduced, or even completely avoided.

[0061] This is advantageously supported by the fact that the second pressing surface 7 of the pressing element 6 is kept at a lower temperature than the first pressing surface 5 of the jaw body 4, and in particular at a temperature lower than the melting temperature of the materials of the welding region 2 and the wall 1.

[0062] This can be achieved by having the pressing element 6 have lower thermal conductivity than the material of the jaw body 4, or by having the pressing element indirectly attached to the jaw body 4 via an insulating element 8, in which case the insulating element 6 has lower thermal conductivity than the material of the jaw body 4. Preferably, the material of the pressing element 6 is silicone. Metal or another plastic may also be selected.

[0063] Due to the lower thermal conductivity of the pressing element 6 and / or insulating element 8 compared to the material of the jaw body 4, the heat flow from the heat source 14 to the second pressing surface 7 is significantly smaller than the heat flow from the heat source 14 to the first pressing surface. To keep the temperature of the second pressing surface 7 lower than that of the first pressing surface, cooling by ambient air is sufficient. Alternatively, the pressing element 6 can also be actively cooled in all possible configurations.

[0064] Figures 3 and 4 show that multiple pressing elements 6 may be used, and the second pressing surfaces 7 of these pressing elements 6 are adjacent to the first pressing surfaces 5 in different / multiple directions. For example, Figures 3A and 4A show pressing elements 6 located adjacent to / below the jaw body 4 in the axial direction of the central longitudinal axis 12, while Figures 3B and 4B show pressing elements 6 located at least substantially radially adjacent to the jaw body 4, or radially outward from the pointed end of the welding arm. Both types of pressing elements 6 can be used simultaneously.

[0065] Figures 3 and 4 further illustrate the gap 9 between the pressing element 6 and the jaw body 4, which may be formed by an insulating element 8 or spacer element 10 located between the pressing element and the jaw body. The gap 9 may be formed alone or additionally by chamfered or rounded edges formed by the edge formation of the opposing edges of the pressing element 6 and the jaw body 4. In the gap region 9, the wall 9 does not contact both pressing surfaces, which causes even less heating in this region.

[0066] In the configurations shown in Figures 3 and 4, the pressing element positioned at the tip of the welding arm shown in Figures 3B and 4B is omitted, and only the pressing element 6 shown in Figures 3A and 4A is provided. In particular, it may be specified that this pressing element 6 contacts the surface area 1b below the welding area 2 that should not be welded, in the axial direction of the axis 12.

[0067] Figures 5 and 6 show specific preferred embodiments of the welding jaw according to the present invention from various different viewpoints, without showing the heating source provided on the jaw body 4. Generally, the heating source 14 may be attached to the surface of the jaw body 4 that is not occupied by the pressing element 6.

[0068] Figures 5 and 6 show that the pressing element 6 is formed as a planar element / plate, and its large, spaced-apart surface in the thickness direction is parallel to the opposite surfaces 4a and 4b of the jaw body 4. These surfaces 4a and 4b are spaced apart in the thickness direction, and a first pressing surface 5 is formed between surfaces 4a and 4b over the thickness.

[0069] The first pressing surface 5 and the second pressing surface 7 each form a concave notch having a notch bottom 5c or 7c and a notch edge 5d or 7d in a cross-section parallel to at least the surfaces 4a and 4b. Each concave notch rises outward from the notch bottom 5c or 7c to the notch edge 5d or 7d. Partial surfaces 5a and 5b of the first pressing surface 5 are located between the notch bottom 5c and the notch edge 5d, and partial surfaces 7a and 7b of the second pressing surface 7 are located between the notch bottom 7c and the notch edge 7d.

[0070] In particular, Figures 6A and 6B show that each concave notch is preferably formed mirror-symmetric with respect to a plane that passes through the bottom of the notch and is perpendicular to the surfaces 4a and 4b. The concave notch of the first pressing surface is preferably precisely fitted to the shape of the outside of the welding region 2 of the spout, so that the wall 1 can be pressed against the welding region in the area to be welded. Substantially, the concave notch of the first pressing surface 5 may coincide with the negative shape of one of the two welding surfaces located opposite each other in the welding region 2.

[0071] The concave notch of the second pressing surface 7 may be the same as the concave notch of the first pressing surface 5 in a cross-section of a plane parallel to surfaces 4a and 4b, but preferably it is different from the concave notch of the first pressing surface 5.

[0072] Figures 6A and 6B clearly show that the angle α1 formed between partial surfaces 5a and 5b of the first pressing surface 5 is greater than the angle α2 formed between partial surfaces 7a and 7b of the second pressing surface 7.

[0073] Furthermore, it is specified here that the notch bottom 7c of the second pressing surface 7 is recessed behind the notch bottom 5c of the first pressing surface 5, particularly with respect to the direction of movement of the welding jaw toward the welding region 2, which is represented here by arrow 15. As a result, the notch bottom 7c lags behind the notch bottom 5c in the direction of movement 15 during the welding process.

[0074] Additionally, the notched edge 7d of the second pressing surface 7 is specified to protrude beyond the notched edge 5d of the first pressing surface 5, and particularly in the direction toward the welding region 2. As a result, the notched edge 7d precedes the notched edge 5d in the direction of motion 15 during the welding process.

[0075] Furthermore, the notched edge 7d of the second pressing surface 7 forms a flat portion 7e that extends longer than the notched edge 5d of the first pressing surface 5, particularly when viewed in the direction of separation of the notched edges 7d, and in particular, the second pressing surface 7 continues outward beyond the first pressing surface 5.

[0076] The configurations in Figures 5 and 6 show that the pressing element 6 may preferably be held between two retaining plates 11, and in particular between two retaining plates containing heat-resistant fibers, such as glass fibers. This is advantageous when the pressing element is formed from a material that is otherwise not sufficiently stable, such as silicone. These retaining plates 11 also provide insulation to the jaw body 4. The retaining plates 11 may also preferably have concave notches, preferably mimicking the contour shape of the concave notches of the first pressing surface 5, that is, identical in shape to the concave notches of the first pressing surface, particularly in planes parallel to surfaces 4a, 4b, but more preferably set back parallel to the concave notches of the first pressing surface, particularly with respect to the direction of motion 15 toward the central longitudinal axis. The bottom of the notch of the retaining plate 11 can be aligned with the bottom of the notch 7c of the pressing element 6, particularly at least at its deepest point. In this configuration, the unit consisting of the pressing element 6 and the two retaining plates 11 surrounding the pressing plate is indirectly attached to the jaw body 4 via the heat insulating element 8. This results in a sufficient temperature reduction at the second pressing surface 7.

[0077] Preferably, during the implementation of the method, the temperature of the first pressing surface is generally higher than 190°C, and the temperature of the second pressing surface is lower than 190°C, preferably lower than 170°C, and particularly lower than 150°C. Preferably, the temperature of the first pressing surface is at least substantially uniform across the surface, and the temperature of the second pressing surface 7 decreases in the direction away from the first pressing surface 5.

Claims

1. A welding jaw for heat-welding the wall (1) of a pouch formed from a plastic film to the welding area (2) of a spout (3) formed from plastic, comprising a jaw body (4) connectable to a heat source, wherein the jaw body (4) has a pressing surface (5), and the pressing surface (5) can press the surface area (1a) of the pouch wall (1) toward the welding area (2) of the spout (3), in a welding jaw, A welding jaw is characterized in that a pressing element (6) is arranged on the jaw body (4), and in particular is attached to the jaw body (4), and the pressing element (6) has a second pressing surface (7) located adjacent to the first pressing surface (5) of the pressing jaw (4), and the second pressing surface (7) can press the wall (1) of the pouch in a direction toward the welding area (2) of the spout (3) or the central longitudinal axis (12) of the spout passage in a non-welding area (1b) located adjacent to the area to be welded area (1a).

2. The welding jaw according to claim 1, characterized in that the pressing element (6) or at least the second pressing surface (7) is formed from a material having lower thermal conductivity than the material of the jaw body (4).

3. The welded jaw according to claim 1 or 2, characterized in that the pressing element (6) is indirectly attached to the jaw body (4) via at least one insulating element (8), and the insulating element (8) is formed of a material having lower thermal conductivity than the material of the jaw body (4).

4. A welding jaw according to any one of claims 1 to 3, characterized in that a gap (9) is formed between the first pressing surface (5) and the second pressing surface (7), and in particular, the wall (1) of the pouch does not come into contact with the welding jaw within the gap (9).

5. The gap (9) is formed by a spacer element (10) positioned between the jaw body (4) and the pressing element (6), having a surface region recessed behind the first pressing surface (5) and the second pressing surface (7), and more particularly by a spacer element (10) that also forms the insulating element (8) as described in claim 3, or The aforementioned gap (9) is formed by the fact that at least one of the opposing edges of the first pressing surface (5) and the second pressing surface (7) is formed with a chamfered portion or a rounded portion. The welding jaw according to claim 4, characterized in that

6. The welding jaw according to any one of claims 3 to 5, characterized in that the spacer element (10) and / or the heat insulating element (8) are formed from a material containing heat-resistant fibers, particularly glass fibers.

7. The welding jaw according to any one of claims 1 to 6, wherein the pressing element (6) is positioned between two retaining plates (11), and preferably the retaining plate (11) located between the pressing element (6) and the jaw body (4) forms the insulating element (8) and / or the spacer element (10) according to claim 3.

8. The welding jaw according to any one of claims 1 to 7, characterized in that the first pressing surface (5) is formed between two surfaces of the jaw body (4) that are located opposite to each other in the thickness direction of the jaw body (4), and the second pressing surface (7) is formed between two surfaces of the pressing element (6) that are located opposite to each other in the thickness direction of the pressing element (6), and the two surfaces of the jaw body (4) that are located opposite to each other and the two surfaces of the pressing element (6) that are located opposite to each other are located in a plane parallel to each other.

9. The welding jaw according to any one of claims 1 to 8, characterized in that the first pressing surface (5) and / or the second pressing surface (7) are formed flat in at least the main surface area in the thickness direction.

10. The welding jaw according to any one of claims 1 to 9, characterized in that the first pressing surface (5) and / or the second pressing surface (7) are concave when viewed in a cross section perpendicular to the thickness direction or parallel to one of the two surfaces located opposite each other, preferably the first pressing surface (5) can surround the welding area (2) in a predetermined area, particularly on one side of the central longitudinal axis (12) of the spout passage, and preferably over a distance of at least 170 degrees around the central longitudinal axis (12).

11. The welding jaw according to claim 10, characterized in that the first pressing surface (5) and / or the second pressing surface (7) each include two sub-surfaces (5a, 5b, 7a, 7b), in particular two flat sub-surfaces (5a, 5b, 7a, 7b), the two sub-surfaces (5a, 5b, 7a, 7b) forming an angle (α) between them that is greater than 90 degrees, preferably greater than 100 degrees, and preferably the two sub-surfaces (5a, 5b, 7a, 7b) transition particularly continuously to each other in the transition region, and preferably rounded, thereby forming a concave shape.

12. The welding jaw according to claim 10 or 11, characterized in that the angle (α2) formed between the partial surfaces (7a, 7b) of the second pressing surface (7) is smaller than the angle (α1) formed between the partial surfaces (5a, 5b) of the first pressing surface (5).

13. The welding jaw according to any one of claims 10 to 12, characterized in that the concave first pressing surface (5) and / or concave second pressing surface (7) are formed symmetrically around a central plane (13) that is particularly parallel to the thickness direction.

14. A welding jaw according to any one of claims 10 to 13, characterized in that the first pressing surface (5) and the second pressing surface (7) each form a concave notch when viewed in a cross-section parallel to the surfaces located opposite to each other, and each notch has a notch bottom (5c, 7c), the notch bottom (5c, 7c) being surrounded by two notch edges (5d, 7d) located opposite to each other, and the notch bottoms (5c, 7c) of both pressing surfaces (5, 7) and / or the notch edges (5d, 7d) of both pressing surfaces (5, 7) are arranged so as not to align with each other or are offset from each other when viewed in a predetermined direction of movement of the welding jaw as specified during welding.

15. The welding jaw according to claim 14, characterized in that the notched edge (7d) of the second pressing surface (7) protrudes beyond the notched edge (5d) of the first pressing surface (5), particularly in the direction toward the welding region (2), and / or the notched bottom (7c) of the second pressing surface (7) is recessed behind the notched bottom (5c) of the first pressing surface (5) with respect to the direction of movement of the welding jaw toward the welding region (2).

16. The welding jaw according to claim 14 or 15, characterized in that the notched edge (7d) of the second pressing surface (7) forms a flat portion (7e) that extends longer than the notched edge (5d) of the first pressing surface (5) when viewed particularly in the direction of separation of the notched edges (7d), and in particular the second pressing surface (7) extends outward beyond the first pressing surface (5).

17. A method for heat-welding the wall (1) of a pouch formed from a plastic film to the welding region (2) of a spout (3) formed from plastic, wherein two welding jaws located on opposite sides of each other are moved toward the welding region (2) from opposite directions, and each welding jaw has one jaw body (4) connected to a heating source (14), and each jaw body (4) has a pressing surface (5), and the pressing surface (5) presses the pouch wall (1) located between the pressing surface (5) and the welding region (2) toward the welding region (2) of the spout (3) in the surface region (1a) to be welded, A method characterized in that a pressing element (6) is arranged on the jaw body (4), and in particular is attached to the jaw body (4), and the pressing element (6) has a second pressing surface (7) located adjacent to the first pressing surface (5) of the jaw body (4), and the second pressing surface (7) presses the wall (1) of the pouch in a direction toward the welding area (2) of the spout (3) or the central longitudinal axis (12) of the spout passage, in a non-welding area (1b) located adjacent to the area to be welded (1a).

18. The method according to claim 17, characterized in that the second pressing surface (7) is kept at a temperature lower than the temperature of the first pressing surface (5).

19. The method according to claim 17 or 18, characterized in that the second pressing surface (7) is moved in a predetermined area to precede and / or lag behind the first pressing surface (5), and in particular when the pressing surfaces (5, 7) extend symmetrically from the inside to the outside, the outer surface area of ​​the second pressing surface (7) is moved to precede the outer surface area of ​​the first pressing surface (5), and the inner surface area of ​​the second pressing surface (7) is moved to lag behind the inner surface area of ​​the first pressing surface (5).

Images