GB2495304A

GB2495304A - Grillage installation apparatus and method

Info

Publication number: GB2495304A
Application number: GB201117126A
Authority: GB
Inventors: Trevor C Burden; Graham Plumley
Original assignee: Francis and Lewis International Ltd
Current assignee: Francis and Lewis International Ltd
Priority date: 2011-10-05
Filing date: 2011-10-05
Publication date: 2013-04-10
Also published as: GB201117126D0

Abstract

A grillage installation apparatus for installing grillage supporting an existing equipment cabinet, the apparatus comprising a grillage base frame 10 permanently located at the site of the cabinet 2, a lifting cradle (14, figure 2A) fastened to the cabinet, and a lifting frame (20, figure 2A) removably fastened to the grillage frame, a lifting mechanism, which may include chain pulls or differential pulleys, connected between the lifting cradle and lifting frame. The grillage frame may be supported by piles 12. In use the grillage base frame is installed surrounding the cabinet, the lifting cradle attached to the cabinet and the lifting frame attached to the grillage base frame. The lifting mechanism is subsequently attached to the lifting frame and the lifting cradle and the cabinet lifted to allow further grillage elements to be installed underneath the cabinet. The lifting frame is then removed.

Description

Method and ADgaratus for Installing Grillage

Background to the Invention

Telecommunications and power distribution networks, as well as other networks, often include external cabinets housing equipment relating to the network. One example of this are telecommunication cabinets housing electronic apparatus forming part of the telecommunications system. Such cabinets may be physically located at the sides of railway lines or roads. Previously such cabinets were supported on top of concrete slabs. However, such concrete slabs tend to fail after a period of time; for example, the concrete itself may degrade and begin to break up, or the ground on which the slab is formed may over time be subject to movement causing the concrete slab to crack. The latter may particularly occur when the cabinets are located next to railway lines and the original concrete slabs have been formed on the railway ballast', which is typically unbound coarse aggregate. Newly installed cabinets may be formed on metal grills, which in turn are secured to metal piles driven into the ground.

Embodiments of the present invention therefore address the problem of replacing existing concrete slabs under existing cabinets.

Summary of the Invention

According to a first aspect of the present invention there is provided a grillage installation apparatus for installing grillage supporting an existing equipment cabinet, the apparatus comprising: a grillage base frame arranged to be permanently located at the site of the cabinet; a lifting cradle arranged to be fastened to the cabinet; and a lifting frame arranged to be removably fastened to the grillage frame, wherein the lifting cradle and lifting frame are arranged to receive a lifting mechanism connected between them.

The lifting cradle preferably comprises two elongate members arranged to be secured to opposing sides of the cabinet. The lifting cradle may further comprise two clamping elements arranged to urge the elongate members towards each other, wherein the elongate members are clamped to the opposing sides of the cabinet.

The elongate members may comprise angle beams.

The lifting cradle may comprise a plurality of lifting eyes arranged to be fastened to the cabinet.

Alternatively, the lifting cradle may comprise one or more elongate elements arranged to be fastened to the underside of the cabinet.

Preferably, the lifting cradle is removably fastened to the cabinet.

The lifting frame may comprise a plurality of elongate support legs arranged to be fastened vertically to and with respect to the grillage base frame. The lifting frame may further comprise a plurality of beams supported by the support legs.

Additionally or alternatively, the apparatus may further comprise a lifting mechanism arranged to be connected between the lifting frame and the lifting cradle. The lifting mechanism may be a plurality of chain pulls.

According to a further aspect of the present invention there is provided a method of installing grillage at the location of an existing equipment cabinet, the method comprising: installing a grillage base frame surrounding the cabinet; attaching a lifting cradle to the cabinet; attaching a lifting frame to the grillage base frame; attaching a lifting mechanism to the lifting frame and the lifting cradle; lifting the cabinet by means of the lifting mechanism and installing further grillage elements underneath the cabinet; and removing the lifting frame.

The lifting cradle may be subsequently removed from the cabinet.

Description of the Drawings

Figures 1A & 15 schematically illustrate in side and plan view respectively an existing telecommunications cabinet mounted on a concrete slab; Figures 2A & 25 show side & plan views respectively of a partially installed grillage according to an embodiment of the present invention; and Figures 3A & 35 show side and plan views respectively of a partially installed grillage according to an embodiment of the present invention with a lifting frame attached.

Description of Embodiments of the present Invention An illustrative example of an existing telecommunications cabinet mounted on a concrete slab is shown in Figures 1A & 16. The cabinet 2 is typically of metal construction and is generally of a rectangular form.

Typically the cabinet is supported on four or more legs that are fixed to the concrete slab. However, in some instances, and as illustrated in the Figures, the cabinet may be mounted to the concrete slab 4 by means of a plinth 6 of smaller plan area than the cabinet. The plinth 6 may be integrally formed with the cabinet or may be separately formed. Figure lB indicates that the concrete slab 4 is of a sufficient area to allow access to the interior of the cabinet by means of the cabinet door 8.

Figures 2A & 2B show an initial stage of the installation of metal grillage as a replacement to the concrete slab in accordance with an embodiment of the present invention. A base frame 10 of metal girders or beams has been assembled surrounding the cabinet 2. As illustrated the base frame is rectangular in shape as this most conveniently surrounds the square based cabinet, however the shape may be any shape as desired for the final grillage provided that the cabinet is surrounded by the frame. The frame has a greater plan area than the existing concrete slab and is mounted to a number of piles 12 driven into the surrounding ground. The piles 12 are driven into the ground to a sufficient depth so as to be substantially unaffected by any subsequent anticipated ground movement.

Also illustrated in Figure 2A, a separate lifting cradle 14 is secured to the base of the cabinet 2. In the particular embodiment illustrated in Figure 2A the lifting cradle includes a pair of angle beams 16 that are clamped to opposite sides of the cabinet base by a pair of threaded studs 18 and nuts, such that the angle beams 16 are tightly fastened against and underneath the cabinet. In preferred embodiments lifting eyes or bolts are formed or secured to either end of each of the angle beams 16.

A lifting frame 20 is subsequently assembled around the cabinet and secured to the grillage base frame 10, as illustrated in Figures 3A & 3B.

The lifting frame includes a number of upright support legs 22 secured at their lower ends to the grillage base frame 10, and a number of generally horizontal beams connected together so as to surround the cabinet 2 but be spaced away from the cabinet, the horizontal beams being connected to the upper ends of the support legs, Consequently, the lifting frame is arranged to surround the cabinet at a certain distance from the base of the cabinet but with a clearance between the lifting frame and the cabinet. In other embodiments the number of horizontal beams may be such so that they do not surround the cabinet. For example, a pair of beams may be supported by the support legs on opposing sides of the cabinet. In further embodiments the lifting frame may not include any horizontal beams, with the upper ends of the support legs being arranged to be directly connected to a lifting mechanism.

One or more lifting mechanisms are subsequently connected between the lifting frame 20 secured to the grillage frame 10 and the lifting cradle 14 secured to the cabinet. The lifting mechanism preferably includes a number of chain pulls (differential pulley) connected between the lifting frame and lifting cradle. For the arrangement illustrated in Figures 2A, 26, 3A & 36 four chains pulls are preferably used, one located at each corner of the lifting frame and connected to the lifting eyes/lugs of the lifting cradle. Corresponding eyes/lugs may be provided on the lifting frame 20 for the chain pulls to be connected to. The cabinet is at this stage separated from the concrete slab, either by unbolting the cabinet from the slab or plinth (where provided) or by cutting. However, the internal electrical connections to the equipment housed within the cabinet are preferably not disconnected (provided enough slack is present in the connections/cabling to accommodate the subsequent lifting operation.

Once the cabinet has been separated from the concrete slab the cabinet is lifted clear of the slab by means of the lifting mechanism. Whilst the height of the lifting frame over the grillage base frame is not a critical distance, it must be sufficient to accommodate the lifting mechanism and allow the cabinet to be lifted by an adequate distance. In this respect, it may be preferred for the height of the horizontal beams of the lifting frame to be selected such that in the event of a mishap during the lifting operation causing the cabinet to fall against one side of the lifting frame, the lifting frame is of a sufficient height relative to the cabinet sides to prevent the cabinet toppling over completely.

With the cabinet in the raised position a number of further elements of the grillage base frame are connected to the base frame underneath the cabinet. The cabinet is subsequently lowered onto the grillage base frame, by means of the lifting mechanism, such that the cabinet is now fully supported by the piled grillage rather than the concrete slab. The lifting frame and optionally the lifting cradle are subsequently dismantled from the grillage support frame and cabinet respectively and any further desired elements added to the grillage to complete it, such as handrails and floor grills. Depending on the particular implementation of the lifting cradle this may be left fastened to the cabinet.

It will be appreciated that various implementations of the lifting cradle, lifting frame and lifting mechanism are possible within the scope of the present invention. For example, the lifting cradle may be formed by a number of lifting eyes/lugs directly connected to the cabinet sides, by bolts or welding for example. Alternatively, where the cabinet is mounted on discrete feet such that access underneath the cabinet is already available prior to any lifting of the cabinet, then one or more lifting beams may be placed beneath the cabinet and the lifting mechanism connected to these beams.

By utilising the method and apparatus of embodiments of the present invention piled support grillage can be installed as a replacement support base for existing cabinets without the need to disconnect the electrical equipment within the cabinet, thus greatly reducing the time required to replace failed concrete slabs.

Claims

<claim-text>Claims 1. Grillage installation apparatus for installing grillage supporting an existing equipment cabinet, the apparatus comprising: a grillage base frame arranged to be permanently located at the site of the cabinet; a lifting cradle arranged to be fastened to the cabinet; and a lifting frame arranged to be removably fastened to the grillage frame, wherein the lifting cradle and lifting frame are arranged to receive a lifting mechanism connected between them.</claim-text> <claim-text>2. The apparatus of claim 1, wherein the lifting cradle comprises two elongate members arranged to be secured to opposing sides of the cabinet.</claim-text> <claim-text>3. The apparatus of claim 2, wherein the lifting cradle further comprises two clamping elements arranged to urge the elongate members towards each other, wherein the elongate members are clamped to the opposing sides of the cabinet.</claim-text> <claim-text>4. The apparatus of claim 2 or 3, wherein elongate members comprise angle beams.</claim-text> <claim-text>5. The apparatus of claim 1, wherein the lifting cradle comprises a plurality of lifting eyes arranged to be fastened to the cabinet.</claim-text> <claim-text>6. The apparatus of claim 1, wherein the lifting cradle comprises one or more elongate elements arranged to be fastened to the underside of the cabinet.</claim-text> <claim-text>7. The apparatus of any preceding claim, wherein the lifting cradle is removably fastened to the cabinet.</claim-text> <claim-text>8. The apparatus of any preceding claim, wherein the lifting frame comprises a plurality of elongate support legs arranged to be fastened vertically to and with respect to the grillage base frame.</claim-text> <claim-text>9. The apparatus of claim 8, wherein the lifting frame further comprises a plurality of beams supported by the support legs.</claim-text> <claim-text>10. The apparatus of any preceding claim further comprising a lifting mechanism arranged to be connected between the lifting frame and the lifting cradle.</claim-text> <claim-text>11. The apparatus of claim 10, wherein the lifting mechanism comprises a plurality of chain pulls.</claim-text> <claim-text>12. A method of installing grillage at the location of an existing equipment cabinet, the method comprising: installing a grillage base frame surrounding the cabinet; attaching a lifting cradle to the cabinet; attaching a lifting frame to the grillage base frame; attaching a lifting mechanism to the lifting frame and the lifting cradle; lifting the cabinet by means of the lifting mechanism and installing further grillage elements underneath the cabinet; and removing the lifting frame.</claim-text> <claim-text>13. The method of claim 12, wherein the lifting cradle is subsequently removed from the cabinet.</claim-text>