Heavy-duty hoist chain

Abstract

A chain has interconnected links each formed by at least one endlessly and continuously circularly woven sheath of tubular shape and circular cross section made of plastic warp yarns and plastic weft yarns surrounding a core. These plastic warp and weft yarns are made of filaments of high tensile strength with a fineness-related maximum tensile strength of at least 5 cN/dtex.

Claims

1. A chain comprised of interconnected links each formed by at least one endlessly and continuously circularly woven sheath of tubular shape and circular cross section made of plastic warp yarns and plastic weft yarns surrounding a core, the plastic warp and weft yarns being made of filaments of high tensile strength with a fineness-related maximum tensile strength of at least 5 cN/dtex.

2. The chain according to claim 1, wherein the plastic warp and weft yarns are multifilament yarns made of plastic filaments.

3. The chain according to claim 1, wherein the plastic warp and weft yarns are formed from thermoplastics based on polyethylene, polyamide, polyethylene terephthalate, or polypropylene.

4. The chain according to claim 1, wherein the plastic warp and weft yarns are made from an ultra-high molecular weight thermoplastic polyolefin.

5. The chain according to claim 1, wherein a fineness of the plastic warp and weft yarns is at least 20 dtex.

6. The chain according to claim 1, wherein ends of an outer layer of the sheath are braided in a direction of lay.

7. The chain according to claim 1, wherein the links have a tensile or breaking strength of at least 1 kN.

8. The chain according to claim 1, wherein the links interlock directly or are coupled to one another by connectors.

9. A method comprising providing the chain according to claim 1 for storing, securing, lifting, and handling cargo and vehicles.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following, the invention is illustrated with reference to an illustrated embodiment described in more detail. Therein:

(2) FIG. 1ABC show different steps in the manufacture of a grommet from an endlessly laid ring made of laid rope and consequently the production of a link,

(3) FIGS. 2A and 2B show two different variants of the rope used in cross-section,

(4) FIG. 2C shows a particularly preferred variant of the one used rope, and

(5) FIGS. 3 and 4 show the chain according to the invention in two basic variants.

SPECIFIC DESCRIPTION OF THE INVENTION

(6) In each of FIGS. 1A to 2C, a grommet is shown having at least one endlessly laid ring of beaten laid rope. In principle, several rings can also be used. The grommet shown in detail FIGS. 1A to 2C is described in more detail below and is used according to the embodiment and as evidenced by FIGS. 3 and 4 to form a chain of interconnected links 6. The chain of FIG. 3 has individual links 6 connected to one another in such a way that the links 6 or the grommets interlock directly. The variant of FIG. 4, on the other hand, has individual links 6 that interlock indirectly via intermediaries such as the connectors 7. The connectors 7 can be steel rings, endless plastic bands or comparable connectors. The chain shown in FIGS. 3 and 4 can in principle be used for storage, securing, lifting and handling of freight, cargo, but also vehicles, as is generally known in the prior art referenced and described above in detail.

(7) As already explained, each link 6 is designed as at least one endlessly laid rope ring made of plastic filaments and in particular as a grommet formed as shown in detail in FIGS. 1 and 2A to 2C. The rope 1 is formed by a core helically surrounded by a plurality of filaments or wires.

(8) According to the embodiment in FIGS. 1ABC, a single rope is used that is continuously wound helically around itself as the core. The two rope ends 1a and 1b that ultimately remain in this context in FIG. 1C each in the laying direction at the end of the laying process form an outer rope layer.

(9) This means that the two rope ends 1a and 1b are engaged, as it were, under the outer rope layer into the interior the grommet and do not project outward, which in principle would also be possible.

(10) FIG. 1A shows an S-twist. But a Z-twist can also be used. If several helically wound ropes for are employed, they can extend counterclockwise and clockwise with one covering the other according to the invention.

(11) The rope 1 is itself comprised of plastic filaments 2, as can be seen in particular in the sectional detail views through the rope 1 in FIG. 2C. In fact, the rope 1 is basically a plastic rope, that is to say a rope 1 made of individual plastic filaments 2. The plastic filaments 2 for their part can be yarns or plastic strands 3 and 4. In this embodiment, the yarns 3 are warp yarns 3, while the yarns 4 are weft yarns 4.

(12) The warp yarns 4 run predominantly longitudinally, here circumferentially of the ring of FIG. 1. In contrast, the weft yarns 4 are transverse to this orientation and run predominantly radially of the ring. To make the strands 2 from the filaments 3 and 4, the strands are twisted together in this embodiments as described above.

(13) According to the embodiment, the warp yarns 3 shown in FIG. 2A all have the same diameter. The same applies to the weft yarns 4 in this variant, where the diameter corresponds to that of the warp yarns 3. As part of the variant of FIG. 2B, however, the warp yarns 3 are of different diameters, whereas in this variant again weft yarns of the same diameter is used. In fact, in FIG. 2B one can see warp yarns 3 with a relatively small diameter or cross-section, whereas in contrast, warp yarns 3 have a larger diameter.

(14) Either way, the warp yarns 3, 3 in conjunction with the weft yarns 4 define a rope 1 made from plastic filaments 2. For this purpose, the rope 1 is laid to have a circular section, made of warp yarns 3 and 3 and weft yarns 4. The warp yarns 3 define in each case different layers 5 on top of one another, as indicated in FIG. 2A. In fact, three layers 5 on warp yarns 3 are used at this point that are interwoven with the respective weft yarns 4 and form a rope 1 of circular section. The braiding process can be detailed using a device or machine for circular weaving, as is described in detail by way of example in above-cited EP 0 059 483.

(15) In the particularly preferred variant according to FIG. 2C for making the circularly braided rope 1, the procedure is such that one or more layers 5 each is formed of a tubular fabric from the warp yarns 3 or weft yarns 4. In fact, the circularly woven rope 1 is produced in this context in the course of a single- or double-tube weaving process. The tubular fabrics are in turn made up of the warp yarns 3 in the longitudinal direction and the weft yarns 4 running transversely on the other hand. In addition, an insert, not shown, may be used. The insert can be a core made of further unillustrated plastic filaments. Other cores are also conceivable.

(16) According to this embodiment, the yarns 3 and 4 have a fineness of at least 20 dtex. In addition, yarns 3 and 4 are high-tensile yarns 3 and 4 with a fineness-related full tensile strength of at least 10 cN/dtex. The yarns 3 and 4 are plastic yarns 3 and 4 and in particular thermoplastic filaments. That is the individual plastic filaments 2 form yarns 3 and 4, the filaments 2 being made, for example, of PE, PA, PET, PP etc.

(17) Plastic filaments 2 are very particularly preferred of polyolefin of ultra-high molecular weight, so-called UHM-WPE (ultra-high-molecular-weight polyethylene). Such plastic filaments 2 and yarns 3 and 4 made from them are, for example, sold under the brand name Dyneema7. The invention is of course not limited to this. In principle, plastic filaments 2 made of polyamide (PA) can also be used at this point or polyester or polyethylene terephthalate (PET). Combinations are of course also conceivable. That is, in this case the yarns 3 and 4 in question are made up of plastic filaments 2 of different plastics.

(18) The breaking strength of the ring produced in this way is generally determined as the sum of the individual strand breaking strengths. That means each individual rope 1 has a corresponding breaking strength. If, for example, the maximum tensile strength related to the fineness is 10 cN/dtex and the rope 1 has a fineness of 20 dtex, the maximum tensile strength is 200 cN or 2N for that considered rope 1 (10 cN/dtex?20 dtx=200 cN). As a rule, however, one is working with a fineness of at least 100 dtex so that the maximum tensile strength of the rope 1 is 10 N.

(19) Typical rope diameters of 4 mm, for example, lead to a strength of mostly more than 100 N, so that if, for example, six ropes 1 are used for the embodiment of FIGS. 1A-C a breaking strength of at least 600 N is obtained. From this sum a loss of laying force must then be deducted from the individual rope breaking strengths in order to be able to determine and establish overall the breaking strength of the ring. The loss of laying force is typically about 10% of the above-mentioned sum (i.e. 10% of 600 n=60 n), so that in the example, a breaking strength of the ring of at least 500 n can be assumed.

(20) The breaking strength of ring forming the link 6 is therefore the same as for the chain as a whole.