Ultrasonic sealing device for filling and packaging machine

Abstract

To provide an ultrasonic sealing device capable of addressing a strength difference in a seal portion between a pack top side and a pack bottom side, thereby enabling improved seal formation.SOLUTION: In the ultrasonic sealing device, a pack top PT side stopper surface 16a and a pack bottom PB side stopper surface 16b of a horn cover 13 are configured as non-coplanar surfaces.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This invention relates to an ultrasonic sealing device for a filling and packaging machine used in a filling and packaging machine that produces content-filled containers by filling and packaging contents such as liquid foods and beverages into containers formed from web-like packaging material mainly made of paper or the like. [Background technology]

[0002] For example, the filling and packaging machine shown in Figure 7 is known for producing content-filled containers by filling and packaging contents such as liquid foods and beverages using a web-like packaging material made by laminating sealant layers made of thermoplastic resin on both sides of a base layer made of paper or the like.

[0003] This filling and packaging machine (1) comprises a rewinder (2) that supports a web-like packaging material (W) wound into a roll, an unwinding device (3) that sequentially unwinds the web-like packaging material (W) from the rewinder (2), a tape application device (4) that applies a sealing tape (S) made of a thermoplastic resin to one edge of one side of the unwound web-like packaging material (W) so that a part of the width of the tape protrudes, a sterilization tank (5) that sterilizes the web-like packaging material (W) by immersing it in a sterilizing solution such as hydrogen peroxide solution, and a tubular packaging material (T) that is formed by overlapping both end edges of the web-like packaging material (W) by a predetermined width and vertically sealing the overlapping part. The device is provided with a vertical sealing device (6) that attaches an overhanging portion of a sealing tape (S) to the inner surface of a tubular packaging material (T) so as to cover the inner surface of the tubular packaging material (T) (one end surface of the packaging material); a content filling device (7) that fills the tubular packaging material (T) with a fluid content using a filling tube (7a) inserted into the tubular packaging material (T) from above; a horizontal sealing device (8) that horizontally seals the tubular packaging material (T) filled with the content at a length equivalent to one container and cuts it in the middle of the width of the horizontal seal portion to form a pillow-shaped content-filled container (C1) in an intermediate form; and a container completion device (9) that forms the container (C1) into a rectangular parallelepiped content-filled container (C2) in its completed form.

[0004] An ultrasonic type horizontal sealing device (8) for such a filling and packaging machine is known (see, for example, Patent Document 1). A conventional ultrasonic sealing device (8) that is the subject of this invention is shown in Figures 8 and 9.

[0005] This ultrasonic sealing device (8) comprises a metal ultrasonic horn (31) and a metal anvil (32) that are arranged to be openable and closable and sandwich the tubular packaging material (T), and a metal horn cover (33) that covers the ultrasonic horn (31).

[0006] The ultrasonic horn 31 is formed with an elongated, flat sealing surface 34. The anvil 32 is formed with an action surface 35 that performs a sealing action facing the ultrasonic horn 31 and the horn cover 33. The horn cover 33 is formed with stopper surfaces 36 that regulate the distance between the sealing surface 34 of the ultrasonic horn 31 and the action surface 35 of the anvil 32, and that sandwich the ultrasonic horn 31 from above and below.

[0007] The working surface 35 of the anvil 32 has a horn receiving portion 35a that presses the tubular packaging material T in cooperation with the sealing surface 34 of the ultrasonic horn 31, and a stopper receiving portion 35b that is provided so as to sandwich the horn receiving portion 35a and that receives the stopper surface 36 of the horn cover 33. The horn receiving portion 35a and the stopper receiving portion 35b are flush with each other.

[0008] Although not shown in the figure, the ultrasonic horn (31) and the anvil (32) are provided with forming flaps that clamp the tubular packaging material (T) from both sides to preform it into a predetermined container shape (e.g., a square cross section).

[0009] As shown in Figure 9, the sealing surface (34) of the ultrasonic horn (31) has a horn protrusion D, which is the amount of protrusion from the stopper surface (36) of the horn cover (33). As a result, when crimping to form a seal, the sealing surface (34) of the ultrasonic horn (31) comes into contact with the tubular packaging material (T) first, and then the stopper surface (36) of the horn cover (33) comes into contact with the tubular packaging material (T).

[0010] The sealing surface (34) of the ultrasonic horn (31) is formed into two strips, one above the other, that extend parallel to each other along the length direction, and a cutter escape groove (37) is formed between the two sealing surfaces (34).

[0011] The horn receiving portions 35a on the working surface 35 of the anvil 32 are formed as two strips, one above the other, that extend parallel to each other along the length and face the two sealing surfaces 34 of the ultrasonic horn 31. A cutter 39 for cutting the transverse seal at the midpoint of its width is housed in a slit 38 formed between the two horn receiving portions 35a so as to be freely retractable.

[0012] During horizontal sealing, the tubular packaging material (T) is locally clamped and deformed at a predetermined height by the sealing surface (34) of the ultrasonic horn (31) and the horn receiving portion (35a) of the working surface (35) of the anvil (32) with a predetermined pressure, and the two flattened portions of the packaging material (T) are crimped together. In this state, an ultrasonic oscillator (not shown) is operated to fuse the inner surfaces of the two crimped portions of the packaging material (T) together, and the sealing tape (S) is fused to the inner surface of the portion of the packaging material (T) opposite the overlap portion. At this time, both end edges of the sealing tape (S) are also fused to the inner surface of the packaging material (T), thereby forming two upper and lower seals (P1) and (P2).

[0013] Then, the horizontal seal portion is cut at the widthwise middle position by a cutter (39), thereby separating the pack bottom (PB) and pack top (PT) of the continuously sealed pillow-shaped content-filled container (C1).

[0014] Steps (38a) facing the ultrasonic horn (31) are formed at the upper and lower edges of the opening of the slit (38) in the anvil (32). Horizontal grooves (40) with a V-shaped cross section are formed in each of the upper and lower operating surfaces (35) of the anvil (32) so as to separate the horn receiving portion (35a) and the stopper receiving portion (35b) from each other. These horizontal grooves (40) are designed to extrude a portion of the molten thermoplastic resin that constitutes the sealant layer on the inner surface of the packaging material (T) portions and form resin pools adjacent to the inner surfaces of the two flat packaging material (T) portions that are fused together by the horizontal seal. This allows for the formation of good horizontal seals with excellent sealing properties and also enables the horizontal seals to be cut smoothly by the cutter (39).

[0015] As shown in Figure 9, in the conventional ultrasonic sealing device (8), the sealing surface (34) of the ultrasonic horn (31), the working surface (35) of the anvil (32), and the stopper surface (36) of the horn cover (33) are all formed symmetrically with respect to the midpoint of the width (the midpoint between the top and bottom in the figure). That is, the sealing surface (34) of the ultrasonic horn (31) is flush with the pack top (PT) side and the pack bottom (PB) side, the action surface (35) of the anvil (32) is also flush with the pack top (PT) side and the pack bottom (PB) side, and the stopper surface (36) of the horn cover (33) is also flush with the pack top (PT) side and the pack bottom (PB) side.

[0016] Note that Fig. 9 is a simplified view of the portion indicated by E2 in Fig. 8. At the portion indicated by E1 in Fig. 8, an additional recess is provided to accommodate the overlap portion (T1) of the tubular packaging material (T), but this is not shown. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-233309 Summary of the Invention [Problem to be solved by the invention]

[0018] As described in Patent Document 1, in the ultrasonic sealing device (8), how to regulate the horn protrusion D is an important factor in order to form a good seal. With the conventional ultrasonic sealing device (8) described above, a difference in strength may occur between the seal portion (P1) on the pack top (PT) side and the seal portion (P2) on the pack bottom (PB) side. In this case, because the pack top (PT) side and the pack bottom (PB) side are sealed simultaneously, if the seal portion (P1) on the pack top (PT) side is weaker than appropriate and the seal portion (P2) on the pack bottom (PB) side is appropriate, the welding energy must be increased to strengthen the seal portion (P1) on the pack top (PT) side. However, this measure also increases the welding energy on the pack bottom (PB) side, which means that the seal portion (P2) on the pack bottom (PB) side is subjected to welding energy that exceeds the appropriate level. This may cause scorching and damage to the barrier layer, resulting in a loss of hermeticity in the finished content-filled container (C2).

[0019] The object of this invention is to provide an ultrasonic sealing device that can address the difference in strength of the seal between the top and bottom sides of the pack and form an even better seal. [Means for solving the problem]

[0020] In order to achieve the above object, the present invention comprises the following aspects.

[0021] 1) An ultrasonic sealing device for a filling and packaging machine, which comprises an ultrasonic horn having an elongated and flat sealing surface, an anvil having an operating surface including a horn receiving portion that presses the tubular packaging material in cooperation with the sealing surface of the ultrasonic horn, and a horn cover that covers the ultrasonic horn and has a stopper surface that regulates the distance between the sealing surface of the ultrasonic horn and the operating surface of the anvil, forms a content-filled container by horizontally sealing the tubular packaging material filled with content in lengths equivalent to one container and cutting the horizontally sealed portion at the middle of the width, An ultrasonic sealing device in which the pack top side stopper surface and the pack bottom side stopper surface of the horn cover are not flush with each other, or the pack top side stopper receiving portion of the working surface of the anvil facing the pack top side stopper surface of the horn cover and the pack bottom side stopper receiving portion of the working surface of the anvil facing the pack bottom side stopper surface of the horn cover are not flush with each other.

[0022] Conventionally, the stopper surface of the horn cover and the working surface of the anvil were flush with each other on the pack top side and the pack bottom side. In contrast, in the ultrasonic sealing device described in 1) above, the pack top-side stopper surface and the pack bottom-side stopper surface of the horn cover are not flush with each other (the horn protrusion (the amount of protrusion of the ultrasonic horn from the horn cover) is different on the pack top side and the pack bottom side), or the pack top-side stopper receiving portion and the pack bottom-side stopper receiving portion of the working surface of the anvil are not flush with each other (the amount of protrusion of the stopper receiving portion relative to the horn receiving portion on the working surface of the anvil is different on the pack top side and the pack bottom side). The pack top-side sealing surface and the pack bottom-side sealing surface of the ultrasonic horn are flush with each other, as in the conventional case.

[0023] Factors that affect the strength of the seal include the pressure, energy, and time applied to the seal surface. With the ultrasonic sealing device described in 1) above, the stopper surface of the horn cover and the stopper receiving portion on the working surface of the anvil, which were previously not distinguished between the top and bottom sides of the pack, can be made to have different dimensions on the top and bottom sides of the pack, making it possible to adjust the pressure applied to the seal on each of the top and bottom sides of the pack.

[0024] 2) The ultrasonic sealing device of 1) above, wherein the working surfaces of the anvils are flush with each other and the pack top side stopper surface of the horn cover is recessed relative to the pack bottom side stopper surface.

[0025] 3) The ultrasonic sealing device of 2) above, wherein the pack top side portion and the pack bottom side portion of the horn cover are formed from separate members.

[0026] 4) The ultrasonic sealing device of 1) above, wherein the stopper surfaces of the horn cover are flush with each other and the pack bottom side stopper receiving portion of the anvil's working surface protrudes further than the pack top side stopper receiving portion. [Effects of the Invention]

[0027] According to the ultrasonic sealing device described above in 1), by making the horn protrusions different between the top and bottom sides of the pack, the pressure applied to the seals on the top and bottom sides of the pack is regulated, thereby optimizing the thickness of each seal and making the strength of the seals on the top and bottom sides equal. Furthermore, instead of using the horn protrusions, the stopper receiving portion of the anvil's working surface facing the stopper surface of the horn cover is made different between the top and bottom sides of the pack, thereby optimizing the thickness of each seal and making the strength of the seals on the top and bottom sides equal. By addressing the difference in seal strength between the top and bottom sides of the pack in this way, an even better seal can be formed.

[0028] According to the ultrasonic sealing device of 2) above, an ultrasonic sealing device having the effect of 1) above can be obtained by machining (e.g., cutting) either or both of the pack top side stopper surface and the pack bottom side stopper surface of the horn cover based on a conventional ultrasonic sealing device.

[0029] According to the ultrasonic sealing device of 3) above, by using a conventional ultrasonic sealing device as a base and using two horn covers, an ultrasonic sealing device having the effect of 1) above can be obtained.

[0030] According to the ultrasonic sealing device of 4) above, an ultrasonic sealing device having the effect of 1) above can be obtained by machining (e.g., cutting) either or both of the pack top side acting surface and the pack bottom side acting surface of the anvil based on a conventional ultrasonic sealing device. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a diagram illustrating the configuration of a conventional ultrasonic sealing device corresponding to the characteristic parts of the ultrasonic sealing device of the present invention. FIG. [Figure 2]1 is a cross-sectional view showing a first embodiment of an ultrasonic sealing device of the present invention. [Figure 3] 1 is a perspective view of an ultrasonic horn and a horn cover showing an example of a first embodiment of an ultrasonic sealing device of the present invention. [Figure 4] 3 is a perspective view of an ultrasonic horn and a horn cover showing another example of the first embodiment of the ultrasonic sealing device of the present invention. FIG. [Figure 5] 10 is a perspective view of an ultrasonic horn and a horn cover showing still another example of the first embodiment of the ultrasonic sealing device of the present invention. FIG. [Figure 6] FIG. 3 is a cross-sectional view showing a second embodiment of the ultrasonic sealing device of the present invention. [Figure 7] 1 is a perspective view showing an example of a filling and packaging machine in which the ultrasonic sealing device of the present invention is used. [Figure 8] FIG. 1 is a perspective view showing an example of a conventional ultrasonic sealing device. [Figure 9] FIG. 1 is a cross-sectional view showing an example of a conventional ultrasonic sealing device. DETAILED DESCRIPTION OF THE INVENTION

[0032] An ultrasonic sealing device 10 according to an embodiment of the present invention will be described below with reference to Figures 1 to 6. The following description will be based on the simplified diagram shown in Figure 9. In each figure, the same components as those shown in Figure 9 will be assigned the same reference numerals, and their description will be omitted. In the following description, the pack top (PT) will be abbreviated as PT, and the pack bottom (PB) will be abbreviated as PB.

[0033] FIG. 1 is a diagram illustrating the configuration of a conventional ultrasonic sealing device (8) corresponding to the characteristic parts of the ultrasonic sealing device (10) of the present invention. In FIG. 1, (a) shows the case where the size of the horn protrusion (the amount of protrusion of the ultrasonic horn (31) from the horn cover (33)) is A, and (b) shows the case where the size of the horn protrusion is B, which is larger than A. The left side of each diagram shows the state before crimping, and the right side of each diagram shows the state after crimping.

[0034] The thicknesses of the upper and lower two seal portions (P1) and (P2) shown in FIG. 9 are regulated by sandwiching the tubular packaging material (T) between the horn cover (33) and the anvil (32). That is, the thicknesses of the seal portions (P1) and (P2) change depending on the size of the horn protrusion D.

[0035] In the case of the example shown in FIG. 1, in the state where A < B with different horn protrusions, the lower stage (b) with a larger horn protrusion shows that the seal becomes stronger as the thickness of the seal portion becomes thinner. On the other hand, the upper stage (a) with a smaller horn protrusion shows that the seal becomes weaker as the thickness of the seal portion becomes thicker.

[0036] In the conventional ultrasonic sealing device (8), as shown in FIG. 9, the sealing surface (34) of the ultrasonic horn (31), the working surface (35) of the anvil (32), and the stopper surface (36) of the horn cover (33) were all formed symmetrically with respect to the middle position in the width (the middle position in the vertical direction in the figure). That is, by making the same dimensions on the PT side and the PB side, it was considered that the strength of the seal portion (P1) on the PT side and the strength of the seal portion (P2) on the PB side would be equal.

[0037] The ultrasonic sealing device (10) of the present invention enables coping with the occurrence of a difference in the strength of the seal portions (P1) and (P2) between the PT side and the PB side, which has not been considered conventionally. In the first embodiment thereof, the ultrasonic horn (31) and the anvil (32) have the same configuration as in the conventional case, and for the stopper surfaces (16a) and (16b) of the horn cover (13), which were the same surface conventionally, the PT side stopper surface (16a) and the PB side stopper surface (16b) of the horn cover (13) are made non - identical surfaces. In the examples shown in FIGS. 2 and 3, the PT side stopper surface (16a) is made concave with respect to the PB side stopper surface (1(6b)).

[0038] According to the ultrasonic sealing device 10 of the first embodiment, the pressure applied to the seal portion P1 on the PT side and the seal portion P2 on the PB side is regulated, thereby optimizing the thickness of each seal portion P1, P2, and making it possible to form the seal portion P1 on the PT side and the seal portion P2 on the PB side with equal strength. In other words, by taking measures to prevent a difference in strength between the seal portions P1, P2 on the PT side and the PB side, it is possible to form a better seal than with the conventional ultrasonic sealing device 8.

[0039] To realize the embodiment shown in FIG. 2, in addition to the example shown in FIG. 3 (where the horn protrusion is changed by setting the difference between the recess amounts a and b from the reference surface so that a > b), it is also possible to make the PB side stopper surface (16b) flush with the reference surface and give the PT side stopper surface (16a) a recess amount (ab) relative to the reference surface, as shown in FIG. 4.

[0040] Also, as shown in FIG. 5, the PT side portion (13a) and the PB side portion (13b) of the horn cover (13) may be formed from separate members, and the PB side stopper surface (16b) and the PT side stopper surface (16a) may be formed on the same plane, with the PT side stopper surface (16a) being given a recess amount (ab) relative to the PB side stopper surface (16b).

[0041] As shown in FIG. 6, in the second embodiment of the ultrasonic sealing device (10) of the present invention, the ultrasonic horn (31) and the horn cover (33) have the same configuration as the conventional one (the sealing surface (34) of the ultrasonic horn (31) and the stopper surface (36) of the horn cover (33) are both flush on the PT side and the PB side), and the anvil (12) has an operating surface (15) consisting of a PT side horn receiving portion (15a), a PT side stopper receiving portion (15b), a PB side horn receiving portion (15c), and a PB side stopper receiving portion (15d), and the PT side stopper receiving portion (15b) and the PB side stopper receiving portion (15d) are not flush with each other. In the illustrated example, the PB side stopper receiving portion (15d) is configured to protrude more than the PT side stopper receiving portion (15b), and the PT side horn receiving portion (15a) and the PB side horn receiving portion (15c) are flush with the PT side stopper receiving portion (15b).

[0042] In this second embodiment, as in the first embodiment, the pressure applied to the PT-side seal portion (P1) and the PB-side seal portion (P2) is regulated, thereby optimizing the thickness of each seal portion (P1) (P2) and making the strength of the PT-side seal portion (P1) and the strength of the PB-side seal portion (P2) equal. In other words, by taking measures to prevent a difference in strength between the PT-side and PB-side seal portions (P1) (P2), a better seal can be formed than with the conventional ultrasonic sealing device (8).

[0043] In the above embodiments, the horn projection is described as being positive (greater than 0). However, if the horn projection is negative, the horn receiving portions 15a, 15c, and 35a of the working surfaces 15 and 35 of the anvils 12 and 32 can be made relatively protruding, or the stopper receiving portions 15b, 15d, and 35b of the working surfaces 15 and 35 of the anvils 12 and 32 can be made relatively recessed, thereby achieving the same effect as when the horn projection is greater than 0, and the horn projection is not limited to being positive.

[0044] 3 to 5 show an example in which the horn cover (13) surrounds the ultrasonic horn (31) on all four sides (in a square-shaped configuration), but the horn cover (13) only needs to have the cross-sectional shape shown in FIG. 2, so it may have no side portions and sandwich the ultrasonic horn (31) from above and below (in a V-shape), or it may have side portions on only one side (in a U-shape).

[0045] In the first embodiment, the PT-side stopper surface 16a of the horn cover 13 is recessed relative to the PB-side stopper surface 16b. However, the PT-side stopper surface 16a of the horn cover 13 may protrude relative to the PB-side stopper surface 16b. In the second embodiment, the PB-side stopper receiving portion 15d of the operating surface 15 of the anvil 12 protrudes relative to the PT-side stopper receiving portion 15b. However, the PB-side stopper receiving portion 15d of the operating surface 15 of the anvil 12 may be recessed relative to the PT-side stopper receiving portion 15b. In either case, the amount of recession or protrusion (values ​​such as a and b shown in FIGS. 3 to 5) is determined appropriately depending on the material and shape of the tubular packaging material T to be sealed, thereby enabling the formation of an optimal seal. [Industrial Applicability]

[0046] The present invention is suitably used as a sealing device when manufacturing packaging containers in which juice or dairy products are filled and sealed using an ultrasonic method. [Explanation of symbols]

[0047] (10): Ultrasonic sealing device for filling and packaging machines (11)(31):Ultrasonic horn (12)(32):Anvil (13)(33):Horn cover (15)(35):Action surface (15a): PT side horn holder (15b): PT side stopper receiving part (15c): PB side horn holder (15d): PB side stopper receiving part (16a): PT side stopper surface (16b): PB side stopper surface (34): Sealing surface (36): Stopper surface (P1): PT side seal (P2): PB side seal (PT): Pack Top (PT) (PB): Pack Bottom (PB) (T): Tubular packaging material

Claims

1. an anvil having an operating surface including a horn receiving portion that cooperates with the sealing surface of the ultrasonic horn to press the tubular packaging material; and a horn cover that covers the ultrasonic horn and has a stopper surface that regulates the distance between the sealing surface of the ultrasonic horn and the operating surface of the anvil, wherein the ultrasonic sealing device for a filling and packaging machine forms a content-filled container by transversely sealing the tubular packaging material filled with content at a length equivalent to one container and cutting the transversely sealed portion at a widthwise intermediate portion thereof, An ultrasonic sealing device in which the pack top side stopper surface and the pack bottom side stopper surface of the horn cover are not flush with each other, or the pack top side stopper receiving portion of the working surface of the anvil facing the pack top side stopper surface of the horn cover and the pack bottom side stopper receiving portion of the working surface of the anvil facing the pack bottom side stopper surface of the horn cover are not flush with each other.

2. 2. The ultrasonic sealing device according to claim 1, wherein the working surfaces of the anvil are flush with each other, and the pack top side stopper surface of the horn cover is recessed relative to the pack bottom side stopper surface.

3. 3. The ultrasonic sealing device according to claim 2, wherein the pack top side portion and the pack bottom side portion of the horn cover are formed of separate members.

4. 2. The ultrasonic sealing device according to claim 1, wherein the stopper surfaces of the horn cover are flush with each other, and the pack bottom side stopper receiving portion of the working surface of the anvil protrudes further than the pack top side stopper receiving portion.

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