JPH0790843B2 - Device for forming a seam at the end of a tube - Google Patents

Description

Detailed Description of the Invention a. FIELD OF THE INVENTION The present invention relates to a tube made of a plastic or laminated material consisting of a plastic and an aluminum foil layer, the end of the tube being used as a container for storing and applying toothpaste or cosmetics. To a device for forming a seam.

B. PRIOR ART AND PROBLEMS Currently, there are three main types of known tubes used to store and apply toothpaste or cosmetics and similar substances. In the past, commonly used types of tubes have been made of light metals, especially aluminum. The ends of the tubes were typically seamed by forming some folds at the ends. However, the seams at the ends of aluminum tubes are often prone to damage during use, so such seams are not sufficiently reliable.

A widely used type of tube is the envelope (envelop
e) is a plastic tube made of an elastic plastic material. Such a tube has the advantage that its shape does not change during use. This type of tube is particularly suitable for use as a container for women's cosmetics, because of its unchanged aesthetic appearance.

Another common type of tube currently in use is a laminated tube made of a laminated material consisting of alternating plastic and aluminum foil layers.
Unlike the tube, which is composed entirely of aluminum, the laminated tube deforms during use due to the placement of the aluminum layer. A commonly used plastic material for such tubes is polyolefin, such as high or low pressure polyethylene or polypropylene. The ends of the plastic or laminated tubes are usually heated at the open ends of the tubes, which are generally circular or elliptical in cross-section, for example until they are flexible, and then the tubes are squeezed together on both sides to form a seam between them. Are spliced together to form. The strength of the seam thus formed is equal to the tear resistance of the plastic foil seamed together inside the tube. The strength of the seam is therefore unacceptable considering that the longitudinal seams of the tube envelope of the tube can withstand twice as much pressure as the seams of this type of terminal can withstand if the latest manufacturing method is used. It is enough.

The seam of the end of the tube is weakened over time by corrosion caused by factors such as aromatics present in the product such as toothpaste contained within the tube. Tests have shown that the strength of the seams on the terminals is reduced to half of their original strength within 6 months. From such observation results, it is naturally necessary to carefully investigate the structure of the seam of the terminal. In order to make it easier to understand the invention and the advantages it provides, it is necessary to explain why the currently used seams are inadequate in terms of durability.

The length of the seam is usually about 5 mm to 10 mm. The seam is formed flat and its cross section is in the form of a straight line. If pressure develops in the tube, the strength of the seam will not be sufficient to prevent this and will tend to tear the sides of the seam. With the passage of time,
The aromatics mentioned above which corrode the seam also act to tear the sides of the seam. This fissure gradually becomes an elliptical cross-sectional shape, eventually leading to a hole at the end of the tube.

C. OBJECTS OF THE INVENTION AND MEANS FOR OBTAINING THE OBJECT One object of the present invention is to provide a device for forming the seams at the ends of a plastic tube or a laminated tube so as to have a greater resistance to strain of the seam. is there.
In a device for forming a seam at the other end of a filled tube which is closed at one end, according to the invention, a first bending device for bending the other end to approximately 90 ° and the other end To a second bending device for further bending up to approximately 180 ° to contact the other end of the folded end between them and change the shape of the other end of the folded end to the other end. Guides are provided that hold the ends of the to about 180 degrees until they are bent.

The seam formed according to the invention does not tear, since the cross-section of the end of the tube always holds a straight form and the opposite side of the tube's jacket cannot move in the direction of opening. Have advantages. This is because another seam is formed on the outside of the tube between the fold and the surface of the tube. Therefore, aromatics contained in the tube cannot penetrate into the seam. The seams formed according to the invention have considerably better strain resistance than known types of seams, since their strength is equal to the tensile strength of the laminated material itself.

Another important advantage of the device of the present invention is that the entire seam forming operation takes place while the tube does not sway in the anteroposterior direction but along a continuous path in the same direction.

E. Embodiments and Functions Advantageous embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the device according to the invention as seen from above with a partial cross section. This device comprises a foam rubber belt 1 for transporting a tube 2 in an upright position with its open end facing upwards. At this stage, the tube 2 has already been filled with the desired substance, for example toothpaste or similar substance. As the tubes 2 enter into the narrow space between the two oppositely arranged conveyor belts 3, 4, the upper ends of each tube 2 are squeezed together, after which the tubes 2 are The conveyor belts 3, 4 are moved further into a folding device consisting of two continuous bending disks 5, 6. The first bending disk 5 bends the end of the tube at an angle of 90 ° with respect to the vertical plane, and
The bending disk 6 finishes bending as shown in FIG. When the tube 2 exits the folding device, the end of the tube 2 is double bent.

The tube is reliably guided and transferred from the first bending disk 5 to the second bending disk 6 with its end portion in the position shown in FIG. This prevents the curved end of the tube from lashing. The tube 2 is likewise guided positively and advances from the second bending disc 6 to a SEAMER consisting of two oppositely arranged movable seam forming belts 7. The seam forming belt 7 slides along the heater 8 to squeeze the end of the tube 2. In order to securely hold the seam forming belt 7 in place in the vertical direction, the seamer is provided with a heating wire 9
Is equipped with. The heating wire 9 is embedded in the heater 8 and attached to the seam forming belt 7, for example by vulcanization. The heater 8 is equipped with a heating cartridge 10. Heat from the heating cartridge 10 is conducted from the heater 8 and the belt 7 to the end of the folded tube 2 which is to be spliced. The ends of the tube 2 are tightly squeezed together by the seam forming belt 7 while being heated. The structure of the seam thus formed will be described in detail with reference to FIGS. 11 and 12. According to the invention, it is also possible to use a seamer with only one heater 8. In that case, the heater 8 is best placed on the side where the end of the tube 2 is bent.

In addition, the device can include a cooling and stamping disc 11 located behind the seamer.
The stamp disk 11 can be used, for example, to print the serial number on the seam.

Figure 10 shows the end of a tube with a seam formed by the method most commonly used today. By this method, a seam 12 is formed between the sides 13 and 14 of the jacket. Seams 12 heat the tube and the sides of the tube 1
Formed by tightly squeezing 3,14 together during cold squeezing.

FIG. 11 shows the end seam of a tube formed by the device of the present invention. The jackets 13 and 14 are tubes each having a substantially circular cross-sectional shape before forming the joint. According to the invention, the jacket is composed entirely of plastics material or laminated from alternating plastics foils and aluminum foils. The most preferred plastic materials for this purpose are polyolefins, for example low- and high-pressure polyethylene or polypropylene. First
In the tubes shown in FIGS. 11 and 12, the jacket is
It is made of a laminated material having two aluminum foil layers 15. The number of aluminum foil layers used can be chosen freely and is not a limitation of the invention. One advantage is obtained by cutting the short portion of the jacket slightly obliquely so that the jacket on the side where the end is about to be bent is short. This makes it possible to form a seam in which the ends of the jacket halves 13 and 14 are arranged in the same plane. A seam 16 is formed between the outer surface of the jacket half 13 and the inner surface of the bent portion. A seam 17 is formed inside the fold between the two jacket halves 13 and 14. Also, the ends of the tube can be heated from the other side, if desired, to form a seam between the jacket halves 13 and 14 before folding. However, this is the case for the illustrated embodiment, which is not necessary as far as the end seam durability is concerned. In FIG. 10, FIG. 11 and FIG. 12,
The seam size is exaggerated for technical reasons and for ease of understanding of the drawings. For example, in FIG. 11, the dimension (L) is about 4-5 mm and the dimension (S) is
Is about 1 mm. In the actual dimensional ratio, the lower edge of the bent portion is not formed as round as shown in FIGS. 11 and 12,
It is sharply formed.

FIG. 12 shows an advantageous embodiment of the present invention. In this embodiment, the ends of the jackets 13, 14 have an oblique shape so that the outer edge 19 of the jacket half 14 is joined to the outer surface of the jacket half 13 after folding and seam formation. Be disconnected. This improves the appearance and further enhances the durability of the seamed ends. If not configured like this,
The structure of the end of the tube is the same as the embodiment shown in Figure 11, i.e. when heated from both sides the seam 16,1
7,18 are formed.

It will be apparent to a person skilled in the art that the present invention is not limited to the embodiments described above, but that various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a plan view of the device of the present invention seen from above showing a partial cross section, FIG. 2 is a cross sectional view of FIG. 1 cut along the line II-II, and FIG. Sectional view taken along the line III-III, FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1, and FIG. 5 is a sectional view taken along the line VV of FIG. Fig. 6, Fig. 6 is a sectional view of Fig. 1 cut along line VI-VI, Fig. 7 is a sectional view of Fig. 1 cut along line VII-VII, and Fig. 8 is Fig. 1 Sectional view cut along the line VIII-VIII, FIG. 9 is a sectional view taken along the line IX-IX of FIG. 1, and FIG. 10 is a sectional view of the seam at the end of the known tube, and FIG. FIG. 12 is a cross-sectional view of the end seam of a tube formed using the apparatus of the present invention, and FIG. 12 shows an advantageous embodiment of the present invention. 1 ... foam rubber belt, 2 ... tube, 3,4 ... conveyor belt, 5 ... first bending disk, 6 ... second bending disk, 7 ... movable seam forming belt, 8 ... heater,
9 ... Heating wire, 10 ... Heating cartridge, 11 ... Cooling and stamp disk, 12 ... Seam, 13,14 ... Outer side part, 15 ... Aluminum foil layer, 16, 17, 18 ... Seam , 19 ...
... outer edge.

Claims (1)

[Claims] 1. A device for forming a seam at the other end of a filled tube closed at one end, which is made of plastic or of aluminum foil with a plastic layer thereon, said other A bending device having a first bending device for bending the other end portion to approximately 90 ° and a second bending device for bending the other end portion to approximately 180 °, and bending the other end portion, After the other end is bent, a seam forming device that forms a seam at the other end, and a conveying device that conveys the tube from the folding device to the seam forming device, the first bending A device extending between the device and a second bending device to contact the other end of the folded end between them such that the shape of the other end of the folded end approximates the other end. Up to 180 ° Hold up gel, a guide,
An apparatus for forming a seam at the other end of a filled tube closed at one end, characterized in that the conveying device has.