GB2300409A

GB2300409A - Lagging for a cable drum

Info

Publication number: GB2300409A
Application number: GB9525670A
Authority: GB
Inventors: Roy Gerald Bellfield; Alan George Rogers
Original assignee: PENTRE GROUP Ltd
Current assignee: PENTRE GROUP Ltd
Priority date: 1994-12-17
Filing date: 1995-12-15
Publication date: 1996-11-06
Anticipated expiration: 2015-12-15
Also published as: GB2300409B; GB9525670D0

Abstract

The present invention proposes lagging for a cable drum which aims to maximise the wound diameter in relation to the overall diameter of the drum. Lagging made of sheet material (1) is applied around the circumference of the drum and dimensioned to span longitudinally across the flanges of the cable drum. Clamps (21) clamp the lagging to the rim of the cable drum flanges. The clamps are spaced at intervals around the circumference of the drum. A plurality of sheets are employed with each sheet occupying part of the circumference. The longitudinal edges of adjacent sheets overlap one another. The sheets are ribbed in the circumferential direction. For wide drums, the required span is formed by welding two or more sheets together.

Description

TITLE: Lagging for a cable drum or the like DESCRIPTION The present invention relates to lagging for a cable drum or the like.

It is common practice to apply lagging to the outside periphery of a cable drum once the cable has been wound onto the drum. The primary purpose of the lagging is to protect the cable from damage either in storage or during transportation. Traditionally we have formed an annular channel in the opposed inside edges of the drum flanges to receive the ends of lengths of timber spanning between the flanges and these are introduced into the channel by way of one or more cut outs in the peripheral wall of the channel.

The thickness of the timber employed for the lagging necessarily increases the overall diameter of the drum and hence, for a given maximum diameter or overall height for transportation purposes, the theoretical capacity of the drum is reduced by that amount. This can become significant, for example, where large diameter expensive cables have to be transported long distances.

Thus, it is an aim of the present invention to overcome this problem by providing an alternative lagging arrangement.

Accordingly, one aspect of the present invention provides lagging for a cable drum or the like comprising one or more sheets of material which in use are applied around the circumference of the drum and which are dimensioned to span longitudinally across the flanges of the cable drum and, in use, are located with respect thereto, and in which the sheets are ribbed to increase their rigidity, characterised in that the ribs extend circumferentially.

We have considered locating the sheets with respect to the cable drum by extending them to project beyond the side edges of the flange and then folding around the flange and whilst this provides a particularly secure arrangement it is time-consuming to apply unless a specialised machine is employed and subsequently difficult to remove. Hence, our solution is to run the sheet material onto the flanges and then simply clamp in place, conveniently at discrete locations. The clamps can be positioned so that the overall height is not compromised.

Accordingly another aspect of the invention provides lagging for a cable drum or the like comprising one or more sheets of material which, in use, are applied around the circumference of the drum and which are dimensioned to span longitudinally across the drum onto a circumferential rim of each flange, but not usually beyond, and in which the lagging sheets are secured to said rims by clamp means engaging with the rim.

It is preferred that the sheet material is ribbed to increase its rigidity and whilst it is possible to envisage the ribs being disposed in a direction parallel to the axis of the drum, ie. extending longitudinally between the flanges, it is preferred that they are disposed in the circumferential direction. The longitudinal extent of the lagging sheets may be formed by securing together one or more sheets in side by side relation. Conveniently the lagging sheets overlap and are secured together by welding. Conveniently, the lagging sheets are provided with lifting handles, say two per sheet, and spaced in the longitudinal direction.

For wider drums, further ribs may also be provided which extend in the longitudinal direction, with one such further rib being disposed preferably adjacent each end of the lagging section.

We envisage using sheet metal for the lagging (especially steel, although other materials may be employed) and to form the ribs by carrying out a pressing operation. Having regard to the concerns for achieving satisfactory strength without significantly increasing the overall thickness of the lagging, we envisage employing a plurality of relatively shallow ribs and usually these will be spaced at equal distances in the lateral direction. It is preferred to form a seating to the opposite ends of the sheet to sit on the peripheral flanges of the cable drum and offset from the remainder of the sheet by forming a joggle in the sheet material.Advantageously the remaining sheet material is set radially inwardly from the seating save for the ribs which can be pressed radially outwardly, in which case they would not normally project beyond the level of the aforesaid seating so that any loading is taken over the area of the flanges rather than on the ribbing. The joggle serves as a lateral positioning and alternatively, the ribbing may be inwardly directed in which case the joggle may be replaced by one of the ribs to minimise inward displacement of the lagging and therefore maximise the load capacity. It is usual to allow for a small gap between the outer periphery of the cable wound onto the drum (ie. the maximum wrap diameter) and the lagging.

The present invention also extends to a cable drum in combination with lagging according to any one of the above described aspects or embodiments.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a lagging sheet according to the invention, Figure 2 is a fragmentary cross-sectional view showing securing of the lagging to a cable drum, Figure 3 is a plan view illustrating different embodiments of lagging installed on a drum, Figure 4 is a section on A-A, Figure 5 is a section on X-X, and Figure 6 is a section on Y-Y.

Referring to the drawings of Figures 1 and 2, a cable drum has a rotational axis 20, and comprises a cylindrical core 10, opposite end flanges 12, each of which has a circumferential rim 14 and radial webs 16.

Lagging 1 for a cable drum comprises sheet material tailored to the width of the cable drum to which it is to be applied as measured across the flanges 12 in the direction of the drum axis. For most practical purposes the lagging will be in discrete lengths, each of which covers a portion of the periphery. Thus, we envisage that a drum with a diameter of approximately 4m and a circumference of approximately 12m, will have lagging sheets applied in say 2m lengths. A single wrap is a possibility but is not currently preferred.

As will be seen from Figure 1, the opposite sides of the lagging sheet define seatings 3, 5 to sit on the respective peripheral rims 14 of the cable drum and the seatings are connected to the remainder of the lagging sheet by an inwardly directed joggle 7. In the illustration, five circumferential ribs 9 are formed by pressing the sheet to increase the strength. Sheets may be joined as necessary to give the required span across the flanges and a lap joint can add strength in place of a rib. The number of ribs will be related to the span and the thickness of the metal used for the lagging thus the illustrated embodiment is merely an example and the invention is not restricted to the number of ribs shown. Sheet metal, especially steel, is preferred for the lagging.

Securing of the lagging to the drum makes use of the out-turned rim 14 to the periphery of the cable drum and a simple clamping arrangement comprising a U-shaped clamp member 21 and a headed bolt 23 in threaded communication with one limb 22 of the clamp member whereby the seating portion 3 of the lagging is held in contact with the outer peripheral rim 14 of the cable drum flange as is apparent from Figure 2. For the above described segmental laggings, each sheet will be clamped using say two clamps to each rim. Conveniently, a location strip is fitted along one longitudinal side of the lagging to overlap with the adjacent lagging sheet.

It is currently envisaged that the strip will fit under the side of the previously positioned lagging so that there is an overlap of the lagging (including location strip) in the circumferential direction.

It will be appreciated that the drawings are not to scale and that for a typical flange span of say 2.3m the sheet metal (where steel) can be of the order of 12mm thick and the joggle and ribs will be between 8 and llmm giving an overall thickness for the lagging of 10 12mm which is a considerable saving over the traditional timber lagging thickness of 76mm.

Referring now to Figures 3 to 6, there is illustrated modified embodiments of lagging. The lagging is essentially the same as that described with reference to Figures 1 and 2 in that it employs circumferential ribs 9, joggles 7 and seatings 3, 5.

Also clamp elements 21.

Figure 4 illustrates a section between the end flanges 12 of a drum, but for an axial length of drum which require two lagging sheets 9' to be joined side by side. The sheets have a joggled top joint as illustrated at 41 and are secured together by welding.

For spans of less than around 2300mum the adjacent circumferential sections of lagging simply overlap as illustrated with reference to Figure 5. For wider spans, typically spans greater than 2300mm, the lagging sheets are provided with two longitudinal ribs 43. The ribs are inset by a short distance from the respective ends of each lagging section so as to leave opposite end sections 45, 47 to from a lap joint. Figure 3 illustrates both the embodiments of Figures 5 and 6, although these would not normally be used together.

The lagging sheets are secured in place by Ushaped clamp elements 21' which have threaded holes to the inner and outer limbs 21a, 21b to receive a respective cone pin socket set screw 51. This design of clamp may be used in place of that described above.

Also illustrated in Figures 3 and 4 are U-shaped lifting handles 53 for manoeuvering the lagging sheets.

Two of these are provided for each segment of lagging and disposed for convenient access to the sides of the drum and positioned approximately midway between the opposites ends of the lagging sheet.

Claims

1. Lagging for a cable drum or the like which has spaced flanges, the lagging comprising one or more sheets of material which in use are applied around the circumference of the drum and which are dimensioned to span longitudinally across the flanges of the cable drum and, in use, are located with respect thereto, and in which the sheets are ribbed to increase their rigidity, characterised in that the ribs extend circumferentially.

2. A cable drum as claimed in claim 1 in which the sheets are located with respect to the cable drum by running the sheet material onto the flanges and then clamping it in place using clamp means.

3. Lagging for a cable drum or the like which has spaced flanges, the lagging comprising one or more sheets of material which, in use, are applied around the circumference of the drum and which are dimensioned to span longitudinally across the drum onto a circumferential rim of each flange, but not usually beyond, and in which the lagging sheets are secured to said rims by clamp means engaging with the rim.

4. Lagging as claimed in claim 3 in which the sheet material is ribbed to increase its rigidity.

5. Lagging as claimed in claim 4 in which the ribs are disposed in a direction parallel to the axis of the drum, ie. extending longitudinally between the flanges.

6. Lagging as claimed in any one of claims 1 to 4 in which the ribs are disposed in the circumferential direction.

7. A cable drum as claimed in claim 2 or any one of claims 3 to 6 in which the clamp means are disposed at spaced circumferential locations around the rim.

8. A cable drum as claimed in claim 7 in which each clamp means is generally U-shaped having two spaced limbs which fit over the rim and further comprising a screw threaded member passing through a complimentary threaded hole in one limb and engageable with the inside of the rim to draw the other limb radially inwardly and thereby hold the lagging against the rim.

9. Lagging as claimed in any one of the preceding claims in which the longitudinal extent of the lagging sheets is formed by securing together two or more sheets in side by side relation.

10. Lagging as claimed in claim 9 in which the lagging sheets overlap and are secured together by welding.

11. Lagging as claimed in any one of the preceding claims in which the lagging sheets are provided with lifting handles.

12. Lagging as claimed in any one of the preceding claims and comprising further ribs which extend in the longitudinal direction.

13. Lagging as claimed in claim 12 in which there is one such further rib disposed adjacent each end of the lagging section.

14. Lagging as claimed in any one of the preceding claims and made from sheet metal.

15. Lagging as claimed in any one of the preceding claims in which there are a plurality of relatively shallow spaced apart ribs.

16. Lagging as claimed in any one of the preceding claims in which a seating is formed to the opposite ends of the sheet to sit on the peripheral flanges of the cable drum and offset from the remainder of the sheet by forming a joggle in the sheet material.

17. Lagging as claimed in claim 16 in which the remaining sheet material is set radially inwardly from the seating.

18. Lagging as claimed in claim 16 or 17 in which the ribs are pressed radially outwardly, but do not project beyond the level of the aforesaid seating so that any loading is taken over the area of the flanges rather than on the ribbing.

19. Lagging as claimed in any one of claims 16 or 17 in which the ribbing is inwardly directed in which case the joggle comprises one of the ribs.

20. Lagging as claimed in any one of the preceding claims in which a plurality of sheets are employed to lag the circumference of the drum and wherein the sheets are applied sequentially one after the other with the adjacent edges in overlapping relation.

21. A cable drum in combination with lagging according to any one of the preceding claims.

22. Lagging for a cable drum constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings of Figures 1 to 3 or as modified according to Figures 4, 5 or 6.