GB2082639A

GB2082639A - Sling belt

Info

Publication number: GB2082639A
Application number: GB8027775A
Authority: GB
Original assignee: MIURA MUMIHIMO KOJYO KK
Current assignee: MIURA MUMIHIMO KOJYO KK
Priority date: 1980-08-28
Filing date: 1980-08-28
Publication date: 1982-03-10
Also published as: GB2082639B

Abstract

A woven sling belt includes a face side (11) and a rear side (12), the face side (11) being formed to haves generally C-shaped or channel-shaped cross- section woven of synthetic resin filaments of a polyamide, the rear side (12) being formed to have a flat cross- section and is woven of synthetic resin filaments which have higher strength but lower elongation than those of the filaments of the face side (11). <IMAGE>

Description

SPECIFICATION Sling belt The present invention relates to a belt for a sling which is used to lift an article, and more particularly to a sling belt made of multi-layered fabric which is composed of a face side to be brought into direct contact with the article thereby to provide a measure of its state of wear and a rear side to be positioned apart from the article thereby to take its share in the strength of the sling.

The present inventor has succeeded in improving the safety and durability of a belt sling whch is composed of a sheath and a core having different colours, as has been disclosed in Japanese Utility Model Registrations Nos. 53-14777 and 53-29811. He has also succeeded in further improving the durability of the sling belt by making one of the layers constituting the sheath, i.e., the layer to be brought into direct contact with the article, thicker than the other layer, as has been disclosed in his preceding Japanese Utility Model Application No.52-39813.

It is an object of the present invention to improve the safety and durability of sling belts.

Another object of the present invention is to provide a fibrous sling belt having a multi-layered construction; especially, a two-layered construction which is composed of a face side having a generally C-shaped or channel-shaped cross-section adapted to be brought into direct contact with an article to be lifted and a rear side positioned apart from the same article and having such a rectangular cross-section as can be tightly fitted in the recess formed in the generally C-shaped or channel-shaped cross-section of the face side.

According to the present invention, there is provided a sling belt for lifting an article, comprising: a face side made of fibres interlaced with one another and adapted to be brought into direct contact with an article during a lifting operation; a rear side made of fibres interlaced wth one another and positioned apart from the article during the same operation; and binder warp yarns intersecting and binding said face and rear sides, said face side being formed to have a generally C-shaped or channel-shaped crosssection and being constructed of warp and weft synthetic resin filaments of such a polyamide as has excellent anti-abrasiveness but low heat resistance, said rear side being formed to have such a flat cross-section as can be received in the recess, which is formed in the generally C-shaped or channelshaped cross-section of sad face side, and constructed by interlacing synthetic resin filaments of KEVLAR (Registered Trade Mark) or polyester, which has higher strength but lower elongation than those of the filaments of said face side, said rear side being formed to have such a rectangular cross-section as can be received in the recess of said face side.

For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows one embodiment of a sling belt in accordance with the present invention; Figure 2 is a diagrammatical cross-section, to an enlarged scale, taken along the line 2-2 in Figure 1; Figure3 is similarto Figure 2 but illustrates an alternative embodiment; Figure 4 is a longitudinal section showing the sling belt having the construction of Figure 2; Figure 5 is also a longitudinal section but shows the construction of Figure 3; Figure 6 is a partial cross-section showing the structure of Figure 2; Figure 7 is a similar to Figure 6 but shows the structure of Figure 3;; Figure 8 is a cross-section, to an enlarged scale, taken along the line 9-9 in Figure 1 but shows a sling belt having a core-sheath construction according to the prior art; and Figure 9 is a section, to an enlarged scale, taken along the line 9-9 of Figure 1 but shows a construction in accordance with the invention.

Referring to the accompanying drawings, Figure 1 generally shows a sling belt which is constructed from a belt in accordance with the present invention.

the sling belt has the construction that is shown in the section 2-2 in Figure 2. Specifically, the reference numeral 11 appearing in Figure 2 indicates an upper or face side which is to be brought into contact with an article to be hoisted. The face side 11 is formed to have a generally C-shaped or channel-shaped crosssection thereby to provide a recess in which a lower or rear side 12 of a rectangular cross-section which is to be free from contact with that article is received.

The reason why the rear side 12 is formed to have such a rectangular cross-section that both its edges are covered by the face side 11 is because both side portions of the latter, which are liable to be abraded, are protected by the same filaments as those of the face side, which gives improved anti-abrasiveness, thereby extending the durability of the belt as a whole.

Turning now to Figure 3, there is shown a belt which is prepared by adding a core 13, if necessary, to the belt having the two-layered construction shown in Figure 2 thereby to provide a three-layered construction. The belts of the above two types are constructed to include the face side 11, the rear side 12 and binder warp yarns 14, and 14' intersecting the two sides 11 and 12, and further the core 13, as shown in longitudinal sections in Figures 4 and 5.

The face side 11 is constructed by plainly weaving warp and weft yarns 1 la and 1 1b of synthetic fibre filaments of polyamide, such as nylon, which has excellent anti-abrasiveness but low heat resistance.

On the other hand, the rear side 12 is constructed by mainly weaving warp yarns 1 2a of synthetic fibre filaments of polyester, such as KEVLAR (Registered Trade Mark owned by E.l. Du Pont de Nemours & BR< Co.), which is stronger than the filaments of the face side 11 while having low elongation, or TETRON (Registered Trade Mark), and weft yarns 12b leading to and from the weft yarns 1 16 of the face side 1 1.

The thus constructed sides 11 and 12 intersect each other by means of the binder warp yarns 14 and 14' made of filaments which are the same as those of the face side 11 while having a smaller denier. The interlacing points of the adjoining binder warp yarns 14 and 14', which extend longitudinally of the belt at a spacing from each other, with the weft yarns 11 b and 12b are consecutively displaced partly to flatten the belt surface and partly to improve the antiabrasiveness. On the other hand, the core 13 is constructed by arranging filaments of synthetic resin fibres of vinylon or polyester longitudinally of the belt in a non-interlacing manner and in parallel with each other.Thus, it goes without saying that the face side 11, rear side 12 and binder warp yarns 14 and 14', and further the core 13, are arranged in position in a plainly woven manner or in a twill- or noninterlaced manner by single weaving operations thereby to provide an integral two- or three-layered belt.

Figures 6 and 7 are section views for clarifying the interlaced constructions of Figures 2 and 3. It will be understood from these Figures that the warp yarns 1 lea forming the face side 11 are constructed by doubling three filaments of nylon whereas the weft yarns 1 2a forming the rear side 12 are constructed from a single filament of KEVLAR (Registered Trade Mark) having a large denier and that both side portions are covered with the elongated warp yarns 1 lea thereby to prevent the edge portions of the belt of this kind from being abraded.

Figure 9 is a section taken along the line 9-9 in Figure 1. As is apparent from a comparison with Figure 8 illustrating a similar section of a sling belt having a core-sheath constructed in accordance with the prior art, the sling according to the present invention is notformed with two abutting outer covers 11c. More specifically, since a sling belt according to the prior art has its outer covers formed into a sheath shape, there are formed the two outer covers ill as shown in Figure 8, when the sling is to be used as shown in Figure 1. Here, since the abrasion of the sling at its periphery is used as a measure of its state of wear, it is unnecessary that the particular portion to be hidden inside when the belts are overlapped into the sling be made so as to have the same colour and yarns as those of the face side of the belt.Therefore, the lifetime of the belt can be extended by eliminating the two outer covers 1 1c and by increasing the thickness of the face side 11 to such an extent as to compensate for their elimination, as shown in Figure 9. It has been revealed by the tests conducted by the inventor, using an anti-abrasiveness tester, that the belt disclosed in Japanese Utility Model Registration No. 53-14777 had its surface abraded after anti-abrasiveness tests of three to five thousand abrasions whereas a belt according to the present invention can endure anti-abrasiveness tests of eighteeen to twenty two thousand abrasions.

According to the yarn constructions exemplified in the foregoing embodiments, if the the temperature, when the sling is used, exceeds the melting point (215 to 220"C) of nylon due to the difference in the heat resisting properties between the respective materials, the limit of usability can be determined in view of the fact that the face side 11 is melted.

However, even after the strength of the face side 11 becomes ineffective, a belt according to the present invention can still maintain its safety factor to a sufficient extent due only to the strength of the rear side 12. Thus, the belt according to the present invention can provide an ideal construction for the sling. In order to enhance the strength thereby to attain improved safety, however, it is sufficient either to treat the belt with a synthetic resin or to cover the belt with a heat-sensitive shrinking tube or an extendible rubber tube which has a smaller peripheral length than the outer peripheral length of the belt proper.

Claims

1. A sling belt for lifting an article, comprising: a face side made of fibres interlaced with one another and adapted to be brought into direct contact with an article during a lifting operation; a rear side made of fibres interlaced with one another and positioned apart from the article during the same operation; and binder warp yarns intersecting and binding said face and rear sides, said face side being formed to have a generally C-shaped or channel-shaped crosssection and being constructed of warp and weft synthetic resin filaments of such a polyamide as has excellent anti-abrasiveness but low heat resistance, said rear side being formed to have such a flat cross-section as can be received in the recess, which is formed in the generally C-shaped or channelshaped cross-section of said face side, and constructed by interlacing synthetic resin filaments of KEVLAR (Registered Trade Mark) or polyester, which has higher strength but lower elongation than those of the filaments of said face side, said rear side being formed to have such a rectangular cross-section as can be received in the recess of said face side.

2. A sling belt as claimed in claim 1, wherein both side portions of said face side forming said generally C-shaped or channel-shaped cross-section are made to extend along both edges of said rear side thereby to form both side portions of said belt.

3. A sling belt as claimed in claim 1 or 2, wherein said face and rear side have different colours.

4. A sling belt as claimed in any preceding claim, further comprising a core sandwiched between said face and rear sides.

5. A sling belt as claimed in claim 4, wherein said core is made of synthetic resin, vinylon or polyester filaments which are arranged longitudinally of said belt in a non-interlaced manner and in parallel with one another.

6. A sling belt as claimed in any preceding claim, wherein said binder warp yarns are made of synthetic resin filaments of polyamide, such as nylon, which are made partly to extend longitudinally of g said belt at a spacing from one another and partly to be alternately interlaced to bind said face and rear sides in such a way that the interlacing points of the adjoining binder warp yarns and said weft filaments are consecutively displaced.

7. A sling belt substantially as hereinbefore described with reference to any of the embodiments illustrated in Figures 1 to 7 and Figure 9 ofthe accompanying drawings.