GB1561193A

GB1561193A - Hoist sling

Info

Publication number: GB1561193A
Application number: GB33397/77A
Authority: GB
Original assignee: Hanfwolf Wolf & Co
Current assignee: Hanfwolf Wolf & Co
Priority date: 1976-08-10
Filing date: 1977-08-09
Publication date: 1980-02-13
Also published as: FI58316B; DE2635879C2; FR2361299B1; DE2635879B1; IT1081050B; FI58316C; FR2361299A1; FI772377A

Description

(54) HOIST SLING (71) We, "HANFWOLF" WOLF & BR< COMPANY, a German Kommanditgesellschaft of Stapenhorststrasse 60, 4800 Bielefeld 1, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a hoist sling for attaching a load to a hoist.

A woven textile hoist sling is proposed in German Patent Specification 1 781 347 which has a relatively loose weave. When carrying a load, this sling undergoes elongation which can also produce oscillation of the load, so that such a sling is not conducive to very accurate load movement.

A hoist sling for bundling packages or the like has been proposed in U.S.A. Patent Specification 3 475 264, which must have a certain elasticity so that after it has been tightened, it fits frictionally against the packages. The sling comprises synthetic plastics material of limited elasticity reinforced with glass fibres. The glass fibre yarns adopt a sinusoidal form when the sling is not under load and under normal working load, they assume a stretched state. The elasticity of the synthetic plastics material is so limited that whilst it initially stretches elastically with the glass fibre yarns, glass fibre yarns soon stretch beyond the elastic limit of the synthetic plastics material which thereafter is no longer elastically deformable.

Apart from the fact that slings of this construction do not permit oscillation-free lifting and moving of loads, the onset of breakage of the reinforcement in such slings is not recognisable from outside. With this sling construction, there is a sudden breakage of the entire cross-section.

According to the invention there is provided a sling for attaching a load to a hoist including an elongated tubular or double layer outer element made of woven knitted or braided textile fabric having a load capacity greater than the rated load for the sling for providing a secondary load carrying capacity of the sling and a flexible inner element made up of metal wires, metal strands, metal ropes or bundles of fibres forming fibrous threads for providing the main load carrying capacity of the sling, the wires, strands ropes or threads of the inner element extending longitudinally, substantially in parallel, in the space in the tube interior or in the space between the two layers without being interwoven with the outer element, and the weave, knit or braiding of the fabric of the outer element being such that a break in the wires, strands, ropes or threads is visible from outside the sling.

Such a sling can offer increased safety in that as damage during operation can be more easily recognisable, operation need not be interrupted immediately, and despite a high load capacity in the longitudinal direction, it can be wound onto small diameter drums by reason of its flexibility.

With one embodiment of sling according to the invention, it is possible to lift and transport a load without oscillations occurring in the sling such as would render it impossible to transport the load in a controlled fashion and to set it down as required.

The sling is constructed and designed so that even the textile fabric outer element can support the rated load with safety.

Therefore, if one or more of the components of the inner element should break due to overloading, the hoist can initially continue to run. Any incipient or even advanced breakage of the inner element components is quite readily detectable from outside the sling and can be checked.

As the outer element enclosing the inner element is made of woven, knitted or braided textile fabric, the components of the inner element cannot be pressed through the fabric when the sling is wound onto a drum.

When the outer element is made of tubular braided material, braid threads serving as binders preferably extend through the outer element fabric.

Two flat textile structures can also be connected to one another face to face by sewn binding threads to form a hoist sling of the invention. In this latter case the seams resulting from the sewing are disposed between two of the wires, strands, ropes or threads located in the interior of the sling.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a partial perspective view of a sling according to the invention; Figure 2 is a cross-section taken on line II-II of Figure 1; Figure 3 is a longitudinal section through the sling of Figures 1 and 2; Figure 4 is a plan view of a crimped wire, strand or rope for a sling according to the invention; Figure 5 shows a textile tubular fabric with longitudinally incorporated crimped wires, shown in the longitudinal section of the sling; Figure 6 is a cross-section through the sling of Figure 5; and Figures 7 and 8 show cross-sections through two further embodiments of sling according to the invention.

Referring to the drawings a sling 1, shown in Figures 1 to 3, a double layer outer element made of two flat elongated structures 2, 3 made of woven or knitted textile fabric, connected to each other by binding threads 4, 5 located at the edges and at intermediate positions across the width of the outer element of the sling. Alternatively the outer element can be made of braided textile fabric in elongated tubular form. The outer element has a load capacity greater than the rated load for the sling for providing a secondary load carrying capacity of the sling.

Extending in the longitudinal direction in intermediate spaces 6 in the tubular interior or between the two layers 2, 3 is a flexible inner element made up of metal wires, metal strands, or metal ropes 7, or bundles of fibres forming fibrous threads 9. This inner element provides the main load carrying capacity of the sling and the wires, strands, ropes or threads forming the components of the inner element extend substantially in parallel without being interwoven with the outer element.

Figures 4, 5 and 6 show that the wires, strands or ropes 8 may be of crimped construction. This results in a particularly elastic form in the longitudinal direction of the sling.

In the embodiment of Figure 7, the intermediate spaces 6 in the tubular or double layer outer element has bundles of fibres 9 therein, for example of carbon, boron or aramide, forming fibrous threads.

Figure 8 shows a sling in which, in the intermediate spaces 6, between the double layer or tubular outer element, there are a plurality of wires, strands, ropes or threads disposed in several layers in straight or crimped form. The multi-layer wires, strands, ropes or threads may be woven to one another.

It is advantageous to construct the outer element, such as the flat structures 2, 3 as densely woven, knitted or braided textile fabric material, so that the wires, strands, ropes or threads laid in the intermediate spaces 6 do not press through the outer element when the sling is wound onto a drum. Moreover the weave, knit or braiding of the outer element must be such that a break in the wires, strands, ropes or threads is visible from outside the sling.

So that the sling is torsion-free, the strands or ropes which are disposed one beside another in the tubular or double layer outer element interior are preferably made alternately with a right-hand (Z) and left-hand (S) direction of pick, i.e. twist.

It is also possible for the wires, strands, ropes or bundles to be made as flat sided or oval or round sectioned components.

WHAT WE CLAIM IS: 1. A hoist sling for attaching a load to a hoist, including an elongated tubular or double layer outer element made of woven, knitted or braided textile fabric having a load capacity greater than the rated load for the sling for providing a secondary load carrying capacity of the sling, and a flexible inner element made up of metal wires, metal strands, metal ropes or bundles of fibres forming fibrous threads for providing the main load carrying capacity of the sling, the wires, strands, ropes or threads of the inner element extending longitudinally, substantially in parallel, in the space in the tube interior or in the space between the two layers without being interwoven with the outer element, and the weave, knit or braiding of the fabric of the outer element being such that a break in the wires, strands, ropes or threads is visible from outside the sling.

2. A hoist sling according to claim 1, including textile binding warps interconnecting the two layers of the double layer outer element between two adjacent wires, strands, ropes or threads.

3. A hoist sling according to claim 1, in which the outer element is tubular made of textile fabric, wherein opposite sides of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. braided textile fabric, the components of the inner element cannot be pressed through the fabric when the sling is wound onto a drum. When the outer element is made of tubular braided material, braid threads serving as binders preferably extend through the outer element fabric. Two flat textile structures can also be connected to one another face to face by sewn binding threads to form a hoist sling of the invention. In this latter case the seams resulting from the sewing are disposed between two of the wires, strands, ropes or threads located in the interior of the sling. The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a partial perspective view of a sling according to the invention; Figure 2 is a cross-section taken on line II-II of Figure 1; Figure 3 is a longitudinal section through the sling of Figures 1 and 2; Figure 4 is a plan view of a crimped wire, strand or rope for a sling according to the invention; Figure 5 shows a textile tubular fabric with longitudinally incorporated crimped wires, shown in the longitudinal section of the sling; Figure 6 is a cross-section through the sling of Figure 5; and Figures 7 and 8 show cross-sections through two further embodiments of sling according to the invention. Referring to the drawings a sling 1, shown in Figures 1 to 3, a double layer outer element made of two flat elongated structures 2, 3 made of woven or knitted textile fabric, connected to each other by binding threads 4, 5 located at the edges and at intermediate positions across the width of the outer element of the sling. Alternatively the outer element can be made of braided textile fabric in elongated tubular form. The outer element has a load capacity greater than the rated load for the sling for providing a secondary load carrying capacity of the sling. Extending in the longitudinal direction in intermediate spaces 6 in the tubular interior or between the two layers 2, 3 is a flexible inner element made up of metal wires, metal strands, or metal ropes 7, or bundles of fibres forming fibrous threads 9. This inner element provides the main load carrying capacity of the sling and the wires, strands, ropes or threads forming the components of the inner element extend substantially in parallel without being interwoven with the outer element. Figures 4, 5 and 6 show that the wires, strands or ropes 8 may be of crimped construction. This results in a particularly elastic form in the longitudinal direction of the sling. In the embodiment of Figure 7, the intermediate spaces 6 in the tubular or double layer outer element has bundles of fibres 9 therein, for example of carbon, boron or aramide, forming fibrous threads. Figure 8 shows a sling in which, in the intermediate spaces 6, between the double layer or tubular outer element, there are a plurality of wires, strands, ropes or threads disposed in several layers in straight or crimped form. The multi-layer wires, strands, ropes or threads may be woven to one another. It is advantageous to construct the outer element, such as the flat structures 2, 3 as densely woven, knitted or braided textile fabric material, so that the wires, strands, ropes or threads laid in the intermediate spaces 6 do not press through the outer element when the sling is wound onto a drum. Moreover the weave, knit or braiding of the outer element must be such that a break in the wires, strands, ropes or threads is visible from outside the sling. So that the sling is torsion-free, the strands or ropes which are disposed one beside another in the tubular or double layer outer element interior are preferably made alternately with a right-hand (Z) and left-hand (S) direction of pick, i.e. twist. It is also possible for the wires, strands, ropes or bundles to be made as flat sided or oval or round sectioned components. WHAT WE CLAIM IS:

1. A hoist sling for attaching a load to a hoist, including an elongated tubular or double layer outer element made of woven, knitted or braided textile fabric having a load capacity greater than the rated load for the sling for providing a secondary load carrying capacity of the sling, and a flexible inner element made up of metal wires, metal strands, metal ropes or bundles of fibres forming fibrous threads for providing the main load carrying capacity of the sling, the wires, strands, ropes or threads of the inner element extending longitudinally, substantially in parallel, in the space in the tube interior or in the space between the two layers without being interwoven with the outer element, and the weave, knit or braiding of the fabric of the outer element being such that a break in the wires, strands, ropes or threads is visible from outside the sling.

tube are connected to one another by sewn binding threads, disposed between any two of the wires, strands, ropes or threads.

4. A hoist sling according to any one of claims 1 to 3, in which the wires, strands, ropes or threads are made of flat sided, or oval or round sectioned components.

5. A hoist sling according to any one of claims 1 to 4, in which the ropes or strands have alternately left hand and right hand directions of twist and are disposed one beside another.

6. A hoist sling according to any one of claims 1 to 5, in which the wires, strands, ropes or threads are crimped.

7. A hoist sling according to any one of claims 1 to 6, including a plurality of the wires, strands, ropes or threads disposed in more than one layer.

8. A hoist sling according to claim 7, in which the multi-layer wires, strands, ropes or threads are woven to one another in crimped or straight form.

9. A hoist sling substantially as hereinbefore described and illustrated with reference to Figures 1 to 3, Figures 4 to 6, Figure 7 or Figure 8 of the accompanying drawings.