GB2175564A

GB2175564A - A stack of insulator strings

Info

Publication number: GB2175564A
Application number: GB08608525A
Authority: GB
Inventors: Motokazu Kozakai
Original assignee: NGK Insulators Ltd
Current assignee: NGK Insulators Ltd
Priority date: 1985-04-10
Filing date: 1986-04-08
Publication date: 1986-12-03
Also published as: GB8608525D0; FR2580260A1; FR2580260B1; GB2175564B

Abstract

A stack of insulator strings comprises a plurality of insulator strings 11 cubically arranged with their axes parallel, the sheds 11a of each arranged between sheds 11a of adjacent insulator strings and having trays 14 interposed between each pair of adjacent horizontal layers of the insulator strings to snugly contact the sheds of said insulator strings to prevent contact therebetween. The trays 14 may be previously formed with recesses and protrusions for contact with the sheds or may be deformed on contact with the sheds when the insulator strings are arranged on a tray horizontally covering lower insulator string layer. The trays may be made of a plastics material, waste paper pulp, or coated expanded metal. The stack of insulator strings may be enveloped by a shrinkable film. <IMAGE>

Description

SPECIFICATION A stack of insulator strings This invention relates to a stack of insulator strings for storage and transportation.

It has been known to stack insulator strings in order to store and transport them in the manner shown in Figures 1 and 2 of the accompanying drawings. A plurality of insulator strings 1 are cubically or three-dimensionally arranged so that their axes 1c are parallel to each other and their sheds 1a are located between sheds of adjacent insulator strings 1. Bar members 2 are provided in parallel with the axes 1c of the insulator strings 1 at vertexes of rectangular isosceles triangles each having a base which is a line connecting centers of two adjacent insulator strings. Each outermost bar member 2a is connected to at least one bar member 2 in the same plane by means of connecting members 3 such as metal bands, wires, cords or the like. A pallet 4 supports all the stacked insulator strings and has bar members 2b having triangular cross-sections to fit between the lowest strings.Japanese Utility Model Application Publication No. 25,489/75 discloses such an insulator string stack.

In such stacked insulator strings, however, the bar members 2 should have substantial thickness and metal bands 3 commensurate with the bars 2 should be used as the connecting members because the insulator strings have considerable weight. Therefore, the stack of insulator strings is made more bulky because of the thick bar members.

Moreover, as the insulator strings 1 are located on the bar members 2 without being retained in their axial directions, there is a risk of the insulator strings 1 inadvertently moving in the axial directions so as to contact and collide with each other, causing damage to their surfaces, during stacking, dismounting and transporting.

Furthermore, if the connecting members 3 are looped steel bands and connect the outermost bar members 2a and the inner bar members 2-1 and 22 for example between insulator strings 1-2 and 13 respectively and 1-1 as schematically shown in Figure 3, the insulator strings must be stacked in the order 1-1, 1-2. 1-3, 1-4 and 1-5 because if the bar members 2-1 and 2-2 are not subjected to the load of strings, the outer strings 1-4 and 1-5 may fall down. In dismounting the stacked insulating strings, the insulating strings must be taken down in the order 1-5,1-4,1-3,1-2 and 1-1. Accordingly, the stacking and dismounting of the insulator strings are troublesome operations, and furthermore a great number of parts for stacking them are required, which make difficult the preparation, management and operation of the stack of insulator strings.

It is a principal object of the invention to provide an insulator string stack which reduces or eliminates the disadvantages of the prior art and which is reduced in volume in comparison with that of the prior art, is easy to stack and dismount and reliably prevents the insulator strings from contacting and colliding with each other. It is also desired that the number of parts required for stacking the insulator strings can be considerably reduced.

A stack of insulator strings according to the invention comprises a plurality of insulator strings cubically arranged with their axes parallel and their sheds arranged between sheds of adjacent insulator strings, and trays interposed between two horizontal layers of the insulator strings to snugly contact the sheds of said insulator strings.

The trays contact the sheds in a manner so as partially to envelop the sheds, i.e. the trays conform to the arrangement of the overlaping sheds.

The trays may be made of a material deformable on contact with the sheds of the insulator strings when the insulator strings are arranged in a horizontal layer on the tray horizontally covering insulator strings immediately therebelow, or the trays may be previously formed with recesses and protrusions in order to snugly contact the sheds of the insulator strings before the trays are arranged on the insulator strings in horizontal layers.

Each tray is preferably provided at its periphery with a reinforcement. The stack of insulator strings is preferably enclosed by a shrinkable film.

The trays may be made of a plastic material, dissolved and moulded waste paper or metal wire mesh such as expanded metal.

Embodiments of the invention will be described below, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a stack of insulator strings of the prior art; Figure 2 is a schematic enlarged front view of a part of the stack shown in Figure 1; Figure 3 is a schematic view explaining the order of stacking of the insulator strings, according to the prior art; Figure 4 is a perspective view illustrating a state where insulator strings are about to be settled on a tray covering already arranged insulator strings, in the formation of a stack embodying the invention; Figure 5 is a perspective view corresponding to Figure 4 of the state where the insulator strings have been settled on the tray, so that the tray is deformed to fit the sheds of the upper and lower insulator strings;; Figure 6 is a schematic view illustrating the deformed tray taken along the line Vl-Vi in Figure 5; Figure 7 is a schematic view similar to Figure 6 taken along the line VII-VII in Figure 5; Figure 8 is a perspective view illustrating an insulator string stack embodying the invention; Figure 9 is a perspective view illustrating another tray to be interposed between insulator strings in another stack embodying the invention; and Figure 10 is a perspective view illustrating a tray of expanded metal to be interposed between insulator strings in yet another stack embodying the invention.

In cubically arranging a plurality of insulator strings 11 so that their axes are parallel to each other and their sheds 11a are located between sheds of adjacent insulator strings 11, according to one embodiment of the invention a tray 12 formed with recesses and projections snugly contacting the sheds 11a of the strings 11 is interposed between two horizontal layers of the insulator strings e.g. as shown in Figures 4 and 5.

A material of the tray 12 may be a metal wire mesh, plastic material, molded pulp, or the like.

Moreover, the tray may be provided at its outer periphery with a reinforcement 14 to improve the mechanical strength of the tray.

In the embodiment of Figures 4 and 5, the recesses and projections are formed in the tray when the insulator strings of one horizontal plane are placed on the tray which is horizontally covering insulator strings in the horizontal plane immediately below the first mentioned horizontal plane.

Sectional configurations of the recesses and protrusions are of sinusoidal wave as shown in Figure 6 taken along the line VI-VI in Figure 5 and sawtoothed shapes as shown in Figure 7 taken along the line VII-VII in Figure 5. Alternatively, depending on the material of the tray, these recesses and projections may be pre-formed.

Example I Trays 12 of dissolved waste paper were previously formed with recesses and protrusions as shown in Figure 9 mating with sheds of insulator strings, to be stacked in the following manner.

A plurality of insulator strings 11 are arranged in a plurality of horizontal planes with the trays formed as above described interposed between the insulator strings. The strings are in respective horizontal planes so that their axes were parallel to each other and the axial directions of the insulator strings adjacent horizontally and vertically are opposite to each other. The sheds of each string are located between the sheds of the strings adjacent horizontally and vertically as shown in Figure 8, i.e.

the strings are axially staggered. A pallet 15 was previously arranged under the lowermost insulator strings. Finally, the stack of insulator strings were packed in a shrinkable film as shown by phantom lines 16 in Figure 8.

The total volume of the stack of insulator strings was 1.55 m3 which was 0.3 m3 smaller than the 1.85 m3 volume of those stacked by the prior art method. The stacking and dismounting operations were easier than in the prior art.

Example II This Example is substantially the same as Example I with exception of the trays. The trays in this case were made of metal wire mesh of 1 mm diameter wires and coated with 1 mm thick plastic coating. These trays were formed to have curved surfaces mating with the sheds of insulating strings to be stacked.

Example III This Example is substantially the same as Example I with exception of the trays. The trays were made of expanded metal and formed into the required shapes by means of forming dies and press.

Upper and lower forming dies were prepared, which were formed with protrusions corresponding to the sheds of insulator strings which are to be arranged in the same manner as in Example I. These upper and lower forming dies were attached to upper and lower die holders of the press to press the expanded metal trays.

The upper and lower dies were preferably formed at their circumferences with flat portions to form the trays with flat edges for the purpose of subsequent processing of the peripheries of the trays. After pressing, the trays were trimmed.

In order to avoid scoring or other marking in vitreous surfaces of the insulator strings by the metallic trays, the expanded model trays were coated with polyethylene by a fluidized-bed coating method. The thickness of the coating was of the order of 0.5 mm. Wood bars having trapezoidal cross-sections were attached onto both sides of peripheries of the trays by nails to form reinforcements of the trays. Edges of the trays extending from the wood frames were bent at right angles to planes of the trays to prevent the edges from leaving the wood frames.

Preferably, the expanded metal was previously collapsed by rollers to obtain uniform plastic coating with good result.

Example IV Trays were made of a plastics material injectionmolded in dies. The trays were integrally formed at their peripheries with pentagonal hollow cylinders in the injection molding, and polygonal wood bars were inserted into the hollow cylinders and retained by nails. The material of the trays was polyethylene and the thickness of the trays was approximately 5 mm.

Example V Trays were made of molded pulp by the use of dies and a heating forming machine. The thickness of the trays was approximately 5 mm. Wood bars having trapezoidal cross-sections were attached onto both sides of the peripheries of the trays by nails to form reinforcements of the trays. In this case, the joint strength between the trays and wood was sufficiently high, it was not needed to bend the edges of the trays.

In order to avoid direct contact of insulator strings, boards of bent corrugated cardboards were inserted between strings. A wood framework was arranged on the insulator string stack to prevent the strings from contacting other objects. However, instead of such a framework, the tray formed as above described may be used.

As the tray in this Example had a high strength, a package of the stack of insulator strings by a mere covering was sufficient. The simple wood framework or pieces of corrugated cardboard were applied to the stack of insulator strings, together with packaging by shrinkable film and bundling by steel bands.

Claims

1. A stack of insulator strings comprising a plurality of insulator strings cubically arranged with their axes parallel to each other and the sheds of each arranged between the sheds of adjacent insulator strings, and trays interposed between each adjacent pair of horizontal layers of the insulator strings and in contact with the sheds of the insulator strings of the pair of layers.

2. A stack of insulator strings as set forth in claim 1, wherein said trays are made of a material deformable on contact with the sheds of the insulator strings when the insulator strings are assembled in a horizontal layer on the tray horizontally convering insulator strings immediately therebelow.

3. A stack of insulator strings as set forth in claim 1, wherein said trays are previously formed with recesses and protrusions for contacting the sheds of the insulator strings, before the trays and insulator strings are arranged ih horizontal layers.

4. A stack of insulator strings as set forth in any one of claims 1 to 3, wherein each said tray is provided at its periphery with a reinforcement.

5. A stack of insulator strings as set forth in any one of claims 1 to 4, wherein said trays are made of a plastics material.

6. A stacked insulator string as set forth in any one of claims 1 to 4 wherein said trays are made of dissolved and molded waste paper.

7. A stack of insulator strings as set forth in any one of claims 1 to 4, wherein said trays are made of metal wire mesh such as expanded metal.

8. A stack of insulator strings as set forth in any one of the preceding claims wherein said stack is enveloped by a shrinkable film.

9. A stack of insulator strings substantially as herein described with reference to and as shown in Figure 4 to Figure 8, Figure 9 or Figure 10 of the accompanying drawings.