Plastic bag for vacuum sealing

Abstract

A plastic bag for vacuum sealing that has a folding line formed during fabrication of a plastic bag to form an air channel communicating with a housing chamber so that when the plastic bag is coupled on a vacuum sealing machine remaining air in the housing chamber may be fully extracted before the plastic bag is sealed.

Description

FIELD OF THE INVENTION

The present invention relates to a plastic bag for vacuum sealing and particularly to a plastic bag for holding goods that has a suction pocket for extracting remaining air then be sealed to prevent external air from entering to protect the quality of the goods.

BACKGROUND OF THE INVENTION

In the general household preserving goods that easily rust or perish is a commonly encountered problem, especially for food. While fresh vegetables and fruits may be held in containers and stored in a refrigerator to maintain the freshness, the general foodstuffs such as biscuits, potato chips, candies cannot be stored in the refrigerator once unpacked and not consumed immediately. They tend to lose the original tasty flavor after having exposed to the air. To remedy this problem, many vendors have developed household sealing machines so that users can store goods to be preserved in an air impermeable thermoplastic bag and extract the remaining air from the thermoplastic bag, and seal the opening of the plastic bag. Thereby the goods can maintain their original taste next time they are removed from the plastic bag.

Owing to the housing chamber of the plastic bag has a selected length, when the sealing machine starts suction and extracts the air, the air around the bag opening is extracted immediately. As the plastic bag is made from thermoplastic material which has viscosity, extracting the air around the bag opening tends to make the sealing machine mistakenly judge that the remaining air in the housing chamber has been completely extracted and proceed sealing operation. As a result, there is still air trapped inside the housing chamber coexisting with the goods held inside. The sealing effect is compromised. In order to remedy this problem, U.S. Pat. No. 4,756,422 (RE34,929) discloses a plastic bag for vacuum sealing. It has air channels formed in a spaced pattern by heat embossing on at least one air impermeable layer to communicate the housing chamber with the bag opening. Through the air channels, the plastic bag opening does not partially seal and all the air in the plastic bag may be extracted before the sealing machine starts sealing operation.

Nevertheless, the cited reference mentioned above has to form the air channels by heat embossing, and the air impermeable layer of the plastic bag has to be thickened. Hence, not only the fabrication process is more complicated the costs of fabrication and material increase greatly and the products become more expensive as well. With increased thickness, more sealing time is required. As most sealing machines are designed to stop air extraction during the sealing process, while the plastic bag is sealed, the air tends to reenter the plastic bag through the air channels, and the actual air extracting and sealing effect is not desirable.

Other references also can be found in U.S. Pat. Nos. 3,809,217 and 4,093,068.

SUMMARY OF THE INVENTION

The primary object of the present invention is to solve the aforesaid disadvantages. The invention provides a plastic bag that has an air channel communicating the bag opening with the housing chamber of the bag at a lower fabrication and material cost without the need of altering the bag thickness. The air channel is formed on a first air impermeable layer or a second air impermeable layer through injection by directly forming a folding line on the first air impermeable layer or the second air impermeable layer. When the plastic bag is coupled with a sealing machine, the remained air inside the housing chamber can be fully extracted through the air channel before sealing process is started.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a schematic view of the first embodiment of the present invention in a fabrication condition.

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a schematic view of the second embodiment of the present invention in a fabrication condition.

FIG. 5 is a front view of the bag opening of the first embodiment of the present invention.

FIG. 6 is a front view of the bag opening of a third embodiment of the present invention.

FIG. 7 is a front view of the bag opening of a fourth embodiment of the present invention.

FIG. 8 is a front view of the bag opening of a fifth embodiment of the present invention.

FIG. 9 is a schematic view of the invention coupling with a sealing machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please referring to FIGS. 1, 2 and 5, the plastic bag 10 according to the invention has a bag opening 14 and may be sealed by a sealing machine 20. The plastic bag 10 consists of a first air impermeable layer 11 and a second air impermeable layer 12 made from an air impermeable material that are bonded together by thermal pressing or supersonic fusion to form a housing chamber 13. Referring to FIG. 2, the plastic bag 10 has a selected length with the bag opening 14 on one end communicating with the housing chamber 13, and a closed end 16 on other end connecting to the bag opening 14 of another plastic bag 10. Referring to FIGS. 3 and 4, the plastic bag 10 may also have only the bag opening 14 on one end. Users can cut off the bag at a length desired according to the quantity of goods to be contained inside.

The main feature of the invention is to form at least one air channel 15a on the first impermeable layer 11 or the second air impermeable layer 12. The air channel 15a is formed by fabricating at least one folding line a on the first impermeable layer 11 or the second air impermeable layer 12 during the integrated injection molding process of the plastic bag 10. The folding line a may be one line or double lines b and c. Refer to FIG. 5 for the air channel 15a formed by a single folding line a that is located outside the housing chamber 13. FIG. 6 illustrates the double lines b and c that form two air channels 15b and 15c outside the housing chamber 13 that have a jointed passage 151 at the front end communicating with the housing chamber 13. FIG. 7 shows another form of double folding lines b and c that form two air channels 15b and 15c outside the housing chamber 13 that communicate with the housing chamber 13 separately. Referring to FIG. 8, the folding line a may also be formed respectively on the first impermeable layer 11 and the second air impermeable layer 12 to form respectively an air channel 15a thereon.

Refer to FIG. 9 for the invention coupling on a sealing machine 20. The plastic bag 10 is coupled on a suction mechanism 21 of the sealing machine 20 (the sealing machine 20 may have various structures. In this embodiment shown in the drawings only the suction mechanism 21 and a heat sealing mechanism 22 are indicated for discussion purpose). When the heat sealing mechanism 22 clamps the plastic bag 10 on the upper side and the lower side, the sealing machine 20 may be activated, and the suction mechanism 21 starts extracts air from the plastic bag 10. As the plastic bag 10 has the air channel 15a leading to the housing chamber 13 from the bag opening 14, the design of the folding line a can prevent the mistaken judgement of air suction were completed caused by the closing of the bag opening 14 at the initial air suction stage by the suction mechanism 21 so that the remaining air in the housing chamber 13 may be fully extracted. After the suction mechanism 21 has finished air extraction, the heat sealing mechanism 22 is activated to seal the bag opening 14 of the plastic bag 10. As the invention does not need to increase the thickness of the plastic bag 10, sealing of the plastic bag 20 can be accomplished rapidly, and the possibility of the external air to reenter the housing chamber 13 through the air channel 15a decreases.

By means of the construction set forth above, the plastic bag 10 of the invention may be made without adding material. The cost is lower and fabrication process also is simpler. Thus total production cost may be reduced. In addition, the sealing time does not increase, and air return flow may also be reduced.

While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.

Claims

1. A plastic bag to be coupled with a vacuum sealing machine, comprising:

a first air impermeable layer and a second air impermeable layer bonded to form a housing chamber to hold goods having at least one bag opening communicating with the housing chamber; and

at least one air channel selectively formed on the first air impermeable layer or the second air impermeable layer by forming at least one folding line on the first air impermeable layer or the second air impermeable layer that communicates the bag opening with the housing chamber;

wherein the plastic bag is coupled with the vacuum sealing machine so that remaining air in the housing chamber is extracted by the sealing machine through the air channel, and the bag opening is sealed thereafter.

2. The plastic bag of claim 1, wherein the folding line is a single folding line to form the air channel outside the housing chamber.

3. The plastic bag of claim 1, wherein the folding line is double folding lines to form two air channels outside the housing chamber that have a joint passage on the front end of the housing chamber.

4. The plastic bag of claim 1, wherein the folding line is double folding lines to form two air channels outside the housing chamber to communicate respectively with the housing chamber.

5. The plastic bag of claim 1, wherein the folding line is formed respectively on the first air impermeable layer and the second air impermeable layer to form respectively an air channel on the first air impermeable layer and the second air impermeable layer.