JPS5815387B2 - Nishikibukuro - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dunnage bag in which two flexible sheets are interposed between the walls of an airtight inner bag in close proximity to an air inlet. This works to prevent the inner bag from tearing during the expansion of the dunnage bag.

BACKGROUND OF THE INVENTION To transport various products or daily necessities, such as paper rolls, etc., these objects are first loaded onto a transport vehicle such as a railway vehicle, and it is necessary to ensure that the loaded objects do not move during transportation.

Therefore, what is generally called a dunnage bag is used.
The dunnage bag is placed between the objects to be transported and when inflated acts as an elastic cushion between the objects and between the objects and the walls of the vehicle.

Therefore, it is possible to prevent the object from being moved and damaged during transportation.

After arriving at the destination, the air can be removed from the dunnage bag, and the object can then be unloaded easily.

Recently, in order to reduce transportation costs, emphasis has been placed on dunnage bags that can be disposed of after the air has been removed from the bag upon arrival at the destination.

Since such dunnage bags or disposable dunnage bags are used only once, the industry has strived to reduce their cost as much as possible.

As a result, dunnage bags have been developed in which the inner bag or air-containing portion of the dunnage bag is made of a thin thermoplastic resin, such as polyethylene or other polyolefin film, and the outside is surrounded by a number of reinforcing sheets of paper.

In dunnage bags with such a structure, the inner bag is used merely as an airtight member, and the necessary strength is maintained by the paper reinforcing sheet.

Therefore, in the above configuration, that is, when a liner made of a thin thermoplastic resin is provided, the strength of the inner bag is relatively weak, and in this point, when the dunnage bag is fully inflated, the paper reinforcement This is not a big problem because the sheet provides the necessary strength, but during the process of inflating the dunnage bag, it may tear due to insufficient strength.

That is, when using a dunnage bag, it is necessary to inflate it as quickly as possible, and ordinary dunnage bags are usually equipped with a valve that penetrates the reinforcing sheet, and this valve is attached to the inner bag of thermoplastic resin. It is heat-sealed to the inner bag and serves to communicate the inside of the inner bag with the outside of the dunnage bag.

To inflate the dunnage bag, this valve is connected to a suitable source of compressed air, such as a tank with a compressor stand, to direct air into the inner bag.

At this time, the inner bag is properly folded inside the reinforcing sheet and is therefore in a state where it can freely vibrate.
When high-pressure air is introduced into the inner bag, the inner bag vibrates greatly at a high frequency due to the vortex generated by the airflow, which may cause the inner bag to tear or tear.

Furthermore, since the cross-sectional area of the valve is very small, the air flow that inflates the dunnage bag is at high speed as it flows into the inner bag, generating a large amount of kinetic energy.

Since ordinary dunnage bags have a valve attached to one of the inner walls, the high-speed, high-energy air flow directly collides with the inner wall of the inner bag on the opposite side, often causing the dunnage bag to expand. The velocity and kinetic energy of the air flow results in puncture of the inner bladder.

The present invention provides a method for preventing an inner bag from tearing when a dunnage bag is inflated, and a dunnage bag constructed in this manner.

The prior art is mainly focused on methods for increasing the strength or reducing the cost of dunnage bags, as described in U.S. Pat.
No. 072270, No. 3199689 and No. 3243
As described in US Pat. No. 822, the only dunnage bag proposed by the inventor of US Pat. No. 3,414,140 is Feldkamp, which is capable of withstanding the external forces acting during the inflation process.

In other words, in the Felt Cam patent, a reinforcing piece is attached to the inner wall of the inner bag of the dunnage bag, and this reinforcing piece is placed on the opposite side of the valve that opens into the inner bag, and is completely fixed or fixed to the inner wall of the dunnage bag. It acts as a reinforcing material that strengthens the area where the reinforcing piece is bonded and attached, and compensates for the lack of strength of the inner bag against the air flow when the dunnage bag is inflated.

The felt cam dunnage bag therefore absorbs the kinetic energy of the inflowing air stream by static means, in other words the reinforcing piece does not separate from the inner bag wall and acts only as a protection.

Experiments have also shown that this reinforcing piece functions as a kind of heat shield.

In other words, while the dunnage bag is inflated, the interior of the inner bag burns on the side opposite to the air inlet, and traces of this burn appear on the surface of the dunnage bag after inflation, but in fact, when high-pressure air is used, Often there is a hole in the inner bag on the opposite side of the valve opening.

This combustion effect or local superheating phenomenon occurs when the high-speed airflow collides with the inner bag wall and the airflow becomes congested in this area. This converts the kinetic energy of the airflow into heat, raising the temperature of both the air and the inner bag, creating a hole in the inner bag wall and a scorched area around it.

Therefore, if a reinforcing piece is provided for the felt cam, the reinforcing piece will absorb the kinetic energy of the airflow more than the inner bag, and when actually observing the felt cam reinforcing piece after the inflation operation, it was found that it was deformed or burned. It turns out that the situation is.

Considering the effects of the felt cam reinforcing piece, it is clear that the felt cam reinforcing piece statically absorbs the kinetic energy of the airflow.

Furthermore, when conducting various experiments using dunnage bags equipped with felt cam reinforcing pieces, the pressure of the incoming air flow was, for example, 3.5 kg/cm2 (50 pcm) despite the reinforcing pieces.
, s, i) It can be seen that it must be limited to the following.

If the inflow air pressure exceeds this value, the reinforcing piece may tear and the dunnage bag may also be damaged.

Furthermore, regardless of the magnitude of the inflow pressure, the wall of the inner bag on the side where the air introduction valve is attached may be damaged.

This is thought to be because the air that collided with the inner wall of the inner bag on the opposite side of the air introduction valve then changed direction and collided with the inner bag again.

However, the felt cam dunnage bag is of no use in protecting the side of the inner bag on the side where the air intake valve is located, and as mentioned above (this can also cause damage if the inner bag vibrates). It is not possible to prevent damage to the inner bag.

In summary, the felt cam dunnage bag is insufficient as a solution to the problem of preventing damage to the inner bag during the inflation process, and the felt cam dunnage bag reinforcement method does not provide an adequate solution to the problem of preventing damage to the inner bag during the inflation process. If the sides cannot be protected and the inflow pressure of the air that inflates the dunnage bag is not limited, the reinforcing piece and the inner wall of the inner bag on the back side may be damaged, and the inner bag may be torn due to vibration. Its protective ability was not sufficient.

The dunnage bag according to this invention has two flexible sheets interposed between the walls of the inner bag, one of which is the flexible sheet.

The flexible sheet is fixed to the inner bag around the opening of the air intake valve (here), and the other flexible sheet is attached to the inner bag inner wall located on the opposite side from the valve opening (here).
This is something that is stuck.

Further, as a partial modification, the second flexible sheet may be configured integrally with the first flexible sheet.

When the dunnage bag of this invention is inflated (this is when the air flow that inflates the dunnage bag flows into the inner bag), the flexible sheet vibrates due to the air flow, which inflates the dunnage bag. Dynamically absorbs the kinetic energy of the air.

At the same time, the presence of these flexible sheets can prevent the inflated airflow from directly colliding with the inner wall of the inner bag.

Next, an embodiment of the invention will be described in detail with reference to FIG.

First, Figures 1 and 2 show an example of a single-use dunnage bag, but its structure is not particularly closely related to this invention; This shows the general structure of

In other words, this dunnage bag is made up of six sheets of paper 12, 14, 16, 18.
20 and 22 are wound around a common axis, and both ends are overlapped and bonded to form a bonded portion 17, resulting in the formation of six tubes.

Note that these tubes are usually made of paper to ensure the necessary strength and to reduce costs.

There are various methods for sealing both ends of a tube, but the one shown in Figures 1 and 2 is one of the most common methods. An integral extension piece 122 to 22a is provided at one end of the constituent sheet, and this is superimposed on the other end of the sheet to form the part 11 in FIG.
Glue as shown in 5.

The inner side of the reinforcing sheets 12, 14, 16.1B, 20 and 22 (herein, an airtight inner bag 29 is arranged, and the inner bag 29 is extruded into a tubular shape) is formed by a thin-walled polyethylene tube. Ru.

Further, both ends of this inner bag are sealed by bending them along one horizontal line I as shown at 9 and heat sealing them.

In addition, by overlapping the end piece 12a of the innermost reinforcing sheet 12 with the folded part 9 of the airtight inner bag 29 (thus reinforcing it), and providing a valve 10 that penetrates the reinforcing sheet one more time. Fluid can be introduced into the inner bag.

The structure of a typical disposable dunnage bag is as described above, but the dunnage bag 30 shown in FIG. 3 has almost the same structure as the dunnage bag shown in FIGS. 1 and 2. A case in which the invention is applied is shown.

For convenience of explanation, some of the six reinforcing sheets shown in FIGS. 1 and 2 are omitted in the dunnage bag shown in FIG.
It is assumed that only two reinforcing sheets 31 and 32 are used.

An inner bag consisting of a front wall 25 and a rear wall 27 is provided inside the dunnage bag 30, and the inner bag is arranged inside the reinforcing sheets 31 and 32.

Valve 10 is used to pass through the reinforcing sheets 31 and 32 and introduce fluid into the inside of the bladder.

To explain in more detail, the eyelet 19 passing through the reinforcing sheets 31 and 32 is provided, and the opposing surface 1 of the eyelet 19 is provided.
3 and 21, the reinforcing sheets 31 and 32 are adhered, and the valve 10 is placed inside the eyelet 19,
Preferably, a flange 23 is provided at one end of the valve 10, and the flange 23 and the outer surface of the valve 10 are made of polyethylene.

Additionally, a retaining ring 1 is provided on the outside of the valve 10 as shown in FIG.
5 is provided, and the annular groove formed in the valve 10 is connected to the retaining ring 15.
This annular groove is not shown in FIG.

Note that the retaining ring 15 is attached to the dunnage bag 30 with respect to the valve 10.
The flange 23 of the valve 10 is pulled outward from the inner surface 21 of the eyelet 19.
is pressed against and serves to secure the valve 10 in place.

Further, in the embodiment shown in FIG. 3, the flange 23 of the valve 10 is bonded to the wall 25 of the inner bag, and if the flange 23 is made of polyethylene and the inner bag is also made of polyethylene, both are heated. It can be easily adhered by sealing.

When the flange 23 is sealed to the wall 25 of the inner bag in this manner, it becomes possible to introduce fluid into the interior of the inner bag via the valve 10.

Note that a valve mechanism configured to allow fluid to flow into the inner bag but not to flow out of the inner bag is housed inside the valve 10.

Since such a valve mechanism is well known in the art, it is omitted from FIG. 3.

According to this invention, a sheet 32 is interposed between the walls 25 and 27 of the inner bag, and the sheet 32 is folded at a fold line 35 into two sheets 33 and 34 and stacked one on top of the other. 32 is shown before being bent in two.

Further, as can be seen from FIGS. 3 and 4, a hole 36 is provided in the first sheet 33, and the hole 36 is arranged at a position aligned with the inlet of the valve 10.

Further, the first sheet 33 is adhered to the wall 25 of the inner bag around the valve 10.

That is, adhesive is applied to the portion of the inner bag inner wall 25 facing the valve flange 23, and the first sheet 33 is attached to the inner bag inner wall 2.
Glue to 5.

The most effective specific method is the first sheet 33
Apply polyethylene to the part facing the inner wall 25 of the inner bag,
This is heat-sealed to the inner bag inner wall 25 at the same side of the valve 10, and if such a method is used, no special adhesive is required.

In the embodiment of FIG. 3, the overlapping sheets 33 and 34 prevent the air flow which inflates the dunnage bag from impinging directly against the walls of the inner bag when the dunnage bag is inflated.

This point is an extremely important advantage of this invention, but
A further unexpected feature has been found to be very effective if the two sheets 33 and 34 are made of a particularly lightweight material.

That is, the flexibility of the sheets 33 and 34
It was found to be very effective in protecting 5 and 27.

The reason is not very clear, but these sheets 33
This is considered to be because the kinetic energy of the expanding airflow is dynamically absorbed by the components 34 and 34.

That is, it is considered that the flexible sheet vibrates during inflation of the dunnage bag, thereby dynamically absorbing the kinetic energy of the air flow that inflates the dunnage bag.

When we actually conducted numerous experiments on the dunnage bag of the present invention, we found that when the sheets 33 and 34 are flexible sheets, the initial inner bag is most likely to be damaged during the process of expanding the dunnage bag. It was found that the vibrations are most active during the easy periods.

Furthermore, due to the vibration at this time, the flexible sheets 33 and 3
In some cases, 4 was torn and completely broken into pieces.

Taking these into consideration, the flexible sheets 33 and 34
It is clear that the energy that causes the dunnage to vibrate is derived from the kinetic energy of the airflow that inflates the dunnage bag, and therefore the kinetic energy of the airflow that inflates the dunnage bag is dissipated by the flexible sheet. This prevents damage to the inner bag.

Furthermore, by continuously changing the flow direction of the air flow that inflates the dunnage bag, damage to the inner bag can be more effectively prevented.

That is, since the flexible sheet constantly vibrates, the angle at which the air flow that inflates the dunnage bag impinges on the sheet changes constantly, and therefore the flow direction of the air flow constantly changes.

In this invention, the walls 25 and 27 of the inner bag are protected by the method described above, and therefore only a portion of one wall of the inner bag is protected by a reinforcing shield and the inflation air is This is completely different from a structure that statically absorbs the kinetic energy of the flow.

The method and structure described with respect to FIG. 3 is also generally effective in protecting against certain phenomena that tend to occur during dunnage inflation.

That is, just before the dunnage bag shown in FIG. 3 is inflated, the wall 27 of the inner bag is close to the wall 25, for example, about 2.5 mm.
Sometimes it approaches 54 cm (1 inch).

Therefore, if the two flexible sheets 33 and 34 are not present, when high-pressure air is sent into the inner bag, the inner bag wall 27
A phenomenon occurs in which the valve opening does not move away and remains as it is, or conversely approaches the opening of the valve 10.

This is caused by the high speed airflow flowing into the inner bag changing its direction.

That is, when the high-speed airflow flows into the inner bag and collides with the inner bag wall 27, the flow direction changes in the direction shown by the arrow in FIG. The high-velocity air flow flowing through will create a low pressure area in this area due to the Bernoulli effect, so that the wall 27 of the inner bag remains stationary or approaches the opening of the valve 10 in reverse.

In any case, the wall 27 of the inner bag is likely to be damaged due to the influence of such a high-speed, high-energy incoming air flow.

Therefore, providing a reinforcing piece only at a position facing the opening of the valve 10 as in the prior art is of no use in preventing the above-mentioned phenomenon.

However, in the present invention, the flexible sheet 34 is disposed in the portion facing the opening of the valve 10 (FIG. 3), so that the flexible sheet 34 maintains a stationary state or absorbs air that inflates the dunnage bag. Even if it is sucked in by the current,
The inner bag wall 27 is not subjected to such hydrodynamic action and is therefore free to move away from the valve opening.

FIG. 6 shows a second embodiment of the invention, and the overall structure of the dunnage bag is almost the same as that shown in FIG.
Flexible sheet 4 interposed between inner walls 25 and 27
The difference from the case of FIG. 3 is that 1 and 42 are made independent of each other, and in FIG. 3, both are connected to each other at a broken line.

Further, in the embodiment shown in FIG. 6, the flexible sheet 42 is fixed to the wall 27 of the inner bag at 43, and the flexible sheet 42
1 is fixed to the wall 25 of the inner bag in the same manner as in FIG.

As for the method of fixing these sheets to the inner bag, the simplest method is to adhere them as described above.More specifically, as explained in FIG. The simplest method is to coat the opposing surfaces with polyethylene or other thermoplastic resin.

That is, in this manner, the sheets 41 and 42 can be heat-sealed to the inner wall of the inner bag.

The functions and advantages of the embodiment of FIG. 6 are exactly the same as those described in FIG. 3.

Although paper is preferably used as the material for the flexible sheet, it is also possible to use other flexible materials, such as flexible sheets of plastic.

In particular, with regard to paper, experimentation with this invention has shown that paper having a basis weight of 18 kg (40 bond), or 0.28 kg per 3000 square centimeters (40 pounds per 3000 square feet), is most suitable.

As mentioned above, it is desirable to provide at least six reinforcing sheets, and it is desirable to use paper as the material for the reinforcing sheets.

It should be noted that the above embodiments are presented merely to explain the present invention, and do not limit the present invention in any way, and the scope of the present invention is as described in the claims.

The embodiments of this invention are as follows.

1. Claims 1 and 2, characterized in that the inner bag is made of thermoplastic resin (dunnage bag described herein).

2. The dunnage bag according to claim 1, wherein the reinforcing sheets 31 and 32 are made of paper.

3 At least 6 paper reinforcing sheets 12, 14° 16.
18, 20, 22. A dunnage bag according to claims 1 and 2, characterized in that the dunnage bag comprises: 18, 20, 22.

4. The dunnage bag according to claim 1, wherein the flexible sheets 41 and 42 are made of paper.

5. A thermoplastic resin is coated on at least one side of flexible sheets 41 and 42 made of paper, and this is adhered to the thermoplastic resin inner bag by heat sealing. The dunnage bag described in paragraph 1.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional, partial perspective view showing a dunnage bag to which this invention can be applied, FIG. 2 is a sectional view of the dunnage bag shown in FIG. 1, and FIG. 4 is a plan view of a flexible sheet used in the dunnage umbrella of the present invention, FIG. 5 is a sectional view showing the inner bag of the dunnage bag, and FIG. 6 is another embodiment of the present invention. 1 is a partial cross-sectional view of an example dunnage bag; FIG. 12 to 22 and 31, 32... reinforcing sheet,
29... Inner bag, 25, 27... Wall of inner bag, 33° 34.41.42... Flexible sheet, 30... Load Matsubukuro, 10... valve.

Claims (1)

[Claims] 1. Consists of an airtight inner bag surrounded by a large number of reinforcing sheets 31, 32 and equipped with a valve 10 penetrating through the reinforcing sheets 31, 32, through which the inside and outside of the airtight inner bag are communicated. In the dunnage bag 30, two flexible sheets 41 and 42 are interposed between the two opposing walls 25 and 27 of the airtight inner bag, and one flexible sheet 41 is having a hole 36 aligned with the valve 10;
In addition, the area around the hole 36 is fixed to one wall 25 of the airtight inner bag, and a part 43 of the other flexible sheet 42 is bonded to the other wall 27 of the airtight inner bag. dunnage bag. 2 Consists of an airtight inner bag surrounded by a large number of reinforcing sheets 31, 32 and equipped with a valve 10 penetrating through the reinforcing sheets 31, 32, so that the inside and outside of the airtight inner bags 25, 27 are communicated by the valve 10. In the configured dunnage bag 30, there is a
Fold it in half with two flexible sheets in between.
Forming a double layer 33.34, one side 33 of the double layer 33.34
The valve 10 has a hole 36, which is provided in the airtight inner bag.
The double layer 3
A dunnage bag characterized in that the other 34 of the airtight inner bag is near one wall 27 of the airtight inner bag and extends to a position facing the hole 36.