GB2207119A - Conveyance bag - Google Patents

Abstract

A conveyance bag (1) for bulk has its hangers (3) for receiving ropes for suspension from a crane hook attached to the bag (1) in a manner to distribute the load. End portions (4) of a folded band (3) are laterally aligned and are superimposed on corresponding portions of a trunk (2) of the bag (1). The portions (4) and the corresponding portions of the trunk (2) are sewn together by first and second sewing threads (5a, 5b). The thread (5a) forms a framing pattern that gradually widens on both lateral sides thereof from the upper to the lower end. At least the lower corners of this framing pattern curve so as to describe circular arcs. The thread (5b) forms a winding pattern that is disposed inside the framing pattern and is repeatedly bent at corners on both lateral sides thereof. <IMAGE>

Description

CONVEYANCE BAG The present invention relates to conveyance bags which are often referred to as "flexible container bags" and are suitable for use in conveyance of bulky cargo such as a bulk material. More particularly, the present invention concerns an improved structure with which hangers are attached to the bag.

Flexible container bags which are formed of base cloth made of materials such as synthetic resin tape yarn and synthetic fiber yarn have been developed for use as conveyance bags, and the introduction of bags of this type has allowed physical distribution to be performed more efficiently. Such a conveyance bag is used as a container for containing bulky cargo such as a bulk material and is thus employed in container transportation. Because these bags can be folded with ease while they are light in weight, are simple in structure and require low costs, a large number of these bags have been used in recent past.

A typical conveyance bag has hangers which are attached to the base cloth by sewing. A conventional structure employed to attach the hangers will be described with reference to Fig. 4.

As shown in Fig. 4, a conventional conveyance bag has a main body 51 which is formed of a piece of base cloth which is in turn formed by weaving materials such as synthetic resin tape yarn and synthetic fiber yarn.

Hangers 53 (only one of which is shown) are attached to a trunk 52 of the main body 51 at four locations on the upper portion of the trunk 52. Each of the hangers 53 consists of a band-shaped member which is formed by, for instance, weaving synthetic resin tape yarn and synthetic fiber yarn, which has an excellent strength, in such a manner that the synthetic fiber yarn extends in the longitudinal direction.

Each of the band-shaped members is folded at the center thereof, and two end portions 54 thereof, which are to be sewn, are aligned in the widthwise direction. The thus aligned end portions 54 are superimposed on corresponding portions of the trunk 52, and the portions 54 of the hangers 53 and the portions of the trunk 52 are sewn together by sewing thread. More specifically, these portions are sewn by thread which forms a rectangular framing pattern 55a, intersecting linear patterns 55b which each extend obliquely, and zigzag patterns 55c which each extend substantially vertically. (These patterns 55a, 55b, and 55c are formed continuously.) The conveyance bag is suspended and conveyed by, for instance, passing a suspension rope (not shown) through each pair of hangers 53, and by hanging the ropes from, for instance, the hook (not shown) of a crane.

However, with this structure in which the portions 54 and the corresponding portions of the trunk 52 are sewn together by forming the rectangular framing pattern 55a, the obliquely extending and intersecting linear patterns 55b, and the substantially vertical zigzag patterns 55c, the following problems are encountered. Namely, when the ropes passed through the hangers 53 are hung from, for instance, the hook of a crane, the folded portions of the hangers 53 are compressed pleated, as shown by two-dotchain lines in Fig. 4, and the bag is suspended along the line passing through the center of the pleated hangers 53.

In consequence, a large load is applied to the part of thread that forms the lower corners of the sewing patterns, thus causing the thread to be broken relatively easily.

Once the thread is broken at the corners, the remaining thread may be broken in sequence. In addition, each of the hangers 53 is attached by folding the band-shaped member at the central portion thereof, laterally aligning the end portions 54 to be sewn, superimposing the aligned end portions 54 on the corresponding portions of the trunk 52, and sewing these portions together. In consequence, if the folded portions of the hangers 53 are twisted, the upper portions of both lateral side portions 54a of the corresponding sewn portions 54 tend to separated from the trunk 2.In particular, when the bag is suspended in the above-mentioned manner, the folded portions of the hangers 53 are compressed and pleated, as described before, thereby causing the lateral side portions 54a of the corresponding sewn portions 54 to separate from the trunk 52 by widths which each increase gradually from the lower to the upper part thereof. If a load is applied to the sewn portions 54 while they are in this condition, the upper corners of the sewing patterns 55a, 55b, and 55c are acted upon by, in addition to the load, the forces which act to separate the sewn portions 54 from the trunk 52. In consequence, the thread is relatively easily broken at theses corners. This may lead, in the end, to breakage of the entire thread. In this way, the conventional conveyance bag has a low strength with which the hangers are attached to the trunk by sewing.

The present invention aims to eliminate the above-stated problems.

The present invention provides a conveyance bag comprising a main body having a trunk, and band-shaped members which are each folded and which each have two end portions to be sewn, the portions being laterally aligned and superimposed on corresponding portions of the trunk of the main body, the portions of theband-shaped members and the corresponding portions of the trunk being sewn together, and wherein the said portions of the band-shaped members and the corresponding portions of the trunk are sewn together by a first sewing thread which forms a framing pattern that gradually widens on both lateral sides thereof from the upper to the lower end, at least the lower corners of the framing pattern curving so as to describe circular arcs, and by a second sewing thread : which forms a winding pattern that is disposed inside the framing pattern and is repeatedly bent at corners on both lateral sides thereof.

The conveyance bag in accordance with the present invention provides the following effect. When the bag is suspended by means of its hangers which each consists of the corresponding band-shaped member, since both lower corners of the framing pattern formed by the first sewing thread are curved, the load can be distributed at each of the corners.Also, when the bag is suspended, even if the folded portions of the hangers are compressed and pleated, thereby causing both lateral side portions of the sewn portions of the hangers to tend to separate from the trunk by widths which each increase gradually from the lower-.to the upper part thereof, since both lateral sides of the framing pattern formed by the first sewing thread each incline in such a manner as to correspond to the increasing separation width, both the load and the forces acting to separate the above-mentioned members can be distributed.

In addition, the second sewing thread forms a winding pattern including transverse segments within the framing pattern formed by the first sewing thread, thereby further ensuring a substantially even distribution of the load.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which Fig. 1 is a perspective view of a conveyance bag in accordance with one embodiment of the present invention; Fig. 2 is an enlarged view of essential parts of the conveyance bag; Fig. 3 is an enlarged view of essential parts of a conveyance bag in accordance with another embodiment of the present invention; and Fig. 4 is an enlarged view of essential parts of a conventional conveyance bag.

Reference is first made to Figs. 1 and 2 which illustrate a first embodiment of the present invention Fig. 1 is a perspective view of a conveyance bag in accordance with the first embodiment, and Fig. 2 is an enlarged view of essential parts of the conveyance bag.

As shown in Figs. 1 and 2, the conveyance bag in accordance with this embodiment has a main body 1. The main body 1 is formed of a piece of base cloth which is formed by weaving materials such as synthetic resin tape yarn and synthetic fiber yarn. If necessary, the base cloth may be laminated with a synthetic resin film so that it is provided with water-proof characteristics. The bag has inlet and discharge ports, neither of which is shown.

Hangers 3 are attached to a trunk 2 of the main body 1 at four locations on the trunk 2. Each of the hangers 3 consists of a band-shaped member which is formed by, for instance, weaving synthetic resin tape yarn and synthetic fiber yarn, which has an excellent strength, in such a manner that the synthetic fiber yarn extends longitudinally along the member. Each of the band-shaped members is folded at the center thereof, and two end portions 4 thereof, which are to be sewn, are aligned in the widthwise direction.The thus aligned end portions 4 to be sewn are superimposed on corresponding portions of the trunk 2, and the portions 4 of the hangers 3 and the corresponding portions of the trunk 2 are sewn together by sewing threads Sa and Sb. More specifically, those portions are sewn.by the thread Sa which forms a framing pattern that gradually widens on inclined lateral sides thereof from the upper to the lower end. Each of the upper and lower corners of the pattern is curved so as to describe a circular arc, and the lower side of the pattern continues from the lower curved corners and curves so as to describe a gentle circular arc.

Those portions are also sewn by the thread 5b which is disposed inside the framing pattern formed by the thread 5a and which forms a winding pattern that bends at corners on both lateral sides thereof.

The conveyance bag having the above-described construction is used in the following way. After bulky cargo such as a bulk material has been received in the bag, the conveyance bag is conveyed by passing a suspension rope, not shown, through each pair of opposite hangers 3, and by hanging the ropes from, for instance, the hook of a crane. During this time, since both the lower corners of the framing pattern formed by the thread 5a are curved, the load borne by each corner can be distributed. At the same time, the folded portion of each of the hangers 3 is compressed and pleated, as shown by two-dot-chain lines in Fig. 2 and, hence, two lateral side portions 4a of the sewn portion 4 each tend to separate from the trunk 2 by a width that increases gradually from the lower to the upper part thereof.According to the present invention, however,*even if a load is applied to the sewn portions 4 while they are in this condition, since both the lateral sides of the framing pattern formed by the thread 5a is applied in such a manner that the pattern widens from the upper to the lower end, i.e., in such a manner that the lateral sides incline in correspondence with the width by which the corresponding side portions of the sewn portion 4 separate from the trunk 2, both the load and the forces that act to separate the sewn portions 4 from the trunk 2 can be distributed by the inclined lateral sides of the sewing pattern.In addition, the thread 5b which forms the winding pattern between the inclined lateral sides of the framing pattern formed by the thread 5a extends in such a manner as to provide a plurality of transverse sewing segments, thereby enabling a substantially even distribution of the load. Thus, according to the present invention, it is possible to prevent the risk of the threads 5a and Sb being easily broken and thereby improve the sewing strength.

Experiments were conducted using the conveyance bag in accordance with this embodiment of the present invention and the conventional conveyance bag which was used as a comparison example. These bags had the trunks 2 and 52, the hangers 3 and 53, and the threads 5a and 5b, and 55a, 55b and 55c, respectively, which were prepared by using the same materials. Each of the bags was tested with respect to its sewing strength by suspending the bag from a crane through a hook on which was hung one pair of hangers 3 or 53 of the bag. The results of the experiments were as follows.With the comparison example, the sewing threads 55a and 55b broke at the corners when a load of no more than It was applied, while, with the bag of the present invention, the threads 5a and 5b did not break even when a load of more than lt was applied.

A second embodiment of the present invention will now be described. Fig. 3 is a view of essential parts of a conveyance bag in accordance with the second embodiment.

The conveyance bag in accordance with this embodiment has the same structure as that of the bag of the previous embodiment, except that the sewing thread 5a forms a different framing pattern. Namely, the central portion of the lower side of the framing pattern formed by the sewing thread 5a is recessed in such a manner as to describe lines which are each substantially parallel to the corresponding lateral side of the framing pattern. The thread 5b is applied in such a manner as to wind within each of the thus bifurcated lower parts of the frame as well.

The conveyance bag having the above-described arrangement in the lower portion of the sewn portions 4 was tested in the same manner as that described before. It was found from the results of the test that the conveyance bag in accordance with this embodiment of the present invention was capable of distributing the load more evenly than the bag of the previous embodiment, thus providing an increased sewing strength. It is conjectured that this is because the bifurcated lower part enabled even distribution of the load to the left and right sides.

As described above, with the conveyance bag in accordance with the present invention, when the bag is suspended by means of its hangers, since both lower corners of the framing pattern formed by the first sewing thread are curved, the load can be distributed at each of the corners. Also, when the bag is suspended, even if the folded portions of the hangers are compressed and pleated, thereby causing both lateral side portions of the sewn portions of the hangers to tend to separate from the trunk by widths which each increase gradually from the lower to the upper part thereof, since both lateral sides of the framing pattern formed by the first sewing thread each incline in such a manner as to correspond to the increasing separation width, both the load and the forces acting to separate the above-mentioned members can be distributed.

In addition, the second sewing thread forms a winding pattern including transverse segments within the framing pattern formed by the first sewing thread, thereby further ensuring a substantially even distribution of the load.

According to the present invention, therefore, it is possible to increase the strength with which the hangers are attached to the trunk by sewing. Thus it will be apparent that the preferred embodiments of the present invention can provide a conveyance bag in which the hangers are attached to the trunk by sewing with an increased strength.

Claims (3)

CLAIMS:

1. A conveyance bag comprising a main body having a trunk and band-shaped members which are each folded and which each have two end portions to be sewn, said portions being laterally aligned and superimposed on corresponding portions of said trunk of said main body said portions of said band-shaped members and said corresponding portions of said trunk being sewn together, and wherein the said portions of said band-shaped members and said corresponding portions of said trunk are sewn together by a first sewing thread which forms a framing pattern that gradually widens on both lateral sides thereof from the upper to the lower end, at least the lower corners of said framing pattern curving so as to describe circular arcs, and by a second sewing thread which forms a winding pattern that is disposed inside said framing pattern and is repeatedly bent at corners on both lateral sides thereof.

2. A conveyance bag according to claim 1, wherein said framing pattern formed by said first sewing thread is recessed at the central portion of the lower side thereof in such a manner that the recessed portion describe lines which are each parallel to the corresponding lateral side of said framing pattern.

3. A conveyance bag substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3.