GB2104022A

GB2104022A - Moving cradle system for inspection of off-shore structures

Info

Publication number: GB2104022A
Application number: GB08223524A
Authority: GB
Inventors: Terence Mayo; John Mcintosh
Original assignee: SALAMIS Ltd
Current assignee: SALAMIS Ltd
Priority date: 1981-08-15
Filing date: 1982-08-16
Publication date: 1983-03-02
Also published as: GB2104022B

Abstract

The system comprises a support beam 10 carrying at each end personnel-carrying, platform arrangements 11-12. The support beam 10 includes a bogey having wheels 16-18 adapted to run on a structure 20 to be inspected. The system is caused to move along the structure by means of air winches 50, 51. <IMAGE>

Description

SPECIFICATION A moving cradle system This invention relates to a moving cradle system.

More particularly, the invention relates to a moving cradle system which has particular application for inspection and maintenance of steel members and the like used, for example, in off-shore structures.

According to the present invention there is provided a moving cradle system comprising a support beam having a platform arrangement suspended from each of its ends, bogey means attached to said support beam for enabling the support beam to run along a bracing member of a structure to be inspected and drive means for effecting movement of the support beam along said member.

Preferably, each platform arrangement comprises three vertically spaced access platforms, Preferably also, said drive means includes a cable and pulley system operated by a pair of winches each located on a respective platform arrangement.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view schematically illustrating a moving cradle system made in accordance with the present invention; Fig. 2 is front elevational view of the system of Fig. 1; Fig. 3 is a top plan view of the system of Fig. 1; and Fig. 4 illustrates the cradle system of the invention running along a horizontal and an angled bracing member.

Referring to the drawings, a moving cradle system comprises a cradle unit 1 having a support beam 10 from the ends of which are suspended respective platform arrangements 11 and 12. The support beam 10 is triangular in section and is of the welded lattice type such as to withstand the complexity of loads resulting from bending, compression and, in particular, torsion.

Each platform arrangement has three access boxes the respective floors of which form vertically spaced horizontal platforms 11 a, 11 b and 11 c and 1 2a, 1 2b and 1 2c. More specifically, the access boxes which are hung from the support beam 10 each comprises welded structural steel frames, when assembled, create three levels of access each complete with handrails, toeboards and sliding ply support panels. As will be described below, each access box is fitted with respective air winches which work independenty of each other.

Unlike conventional cradles, the unit will remain balanced when only one winch is operated.

Intermediate the ends of the support beam 10 there is provided a hinged bogey comprising two pairs of downwardly extending support structures 13, 14, each structure carrying two rollers 15, 16 and 17, 1 8 respectively, adapted to engage a steel bracing member 20 straddled by the cradle and along which the cradle may run. The steel member 20 can be horizontal or inclined as illustrated in Fig. 3, the hinged bogey permitting the suspension of the platform arrangements 11, 1 2 on the support beam 10 to be such that the platforms ila, llb, llcand 12a, 12b, l2carealways horizontal.

The support structure 1 3 comprises a first pair of arms 1 3a, 13b having respective ones of their ends connected together and hinged to the support beam at 33a, their respective remote ends carrying respective wheels 1 5, 1 6, and a second pair of arms 1 3c, 1 3d hinged to the support beam at 33b and again having their remote ends connected to the respective wheels 1 5, 1 6. The remote ends of the arms 13a, and 1 3c are connected to the remote ends of the arms 1 3b and 1 3d by a tie member 13e. In a similar manner, the support structure 14 comprises analogous arms 14a to 14e.

In use, the hinged bogey is clamped to the support beam and tightened at the same angle to the horizontal as the bracing member 20 along which it runs thereby retaining the access platforms in a horizontal position. The wheels 1 5 to 1 8 enable the trolley to run along the bracing member 20 smoothly and accurately thus providing close access for inspection and maintenance personnel. The wheels 1 5 to 18 are made of polypropylene, have sealed bearing and are fitted with guards to protect them from blasting grit, paint spray, etc.

To effect movement of the cradle unit 1 along the steel bracing member 20 and to effect lowering of the unit on to the member, the moving cradle system is provided with a cable/winch system which comprises pulleys 40, 41,42. 43 mounted on the support beam 10, cabling 60, 61 and a pair of air powered winches 50, 51 located one on each platform arrangement. The whole system is suspended by a cable 22 fixed to two suitable spaced suspension points, the cable 22 engaging a wheeled trolley 21 fixed to the cross beam 10.

There has thus been described a moving cradle system which is in the form of a personnel carrying cradle/trolley and designed primarily for inspection and maintenance work on off-shore streel structures but its use is not limited to these structures. The system is self-driven, powered and controlled from the platforms. It has a capability for vertical and horizontal movement anywhere in the vertical plane between two fixed suspension points. It can operate on both horizontal and angled members, the design of the beam being such that the floors in the platforms are always in the horizontal plane.

Modifications and improvements may be incorporated without departing from the scope of the invention.

1. A moving cradle system comprising a support beam having a platform arrangement

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A moving cradle system This invention relates to a moving cradle system. More particularly, the invention relates to a moving cradle system which has particular application for inspection and maintenance of steel members and the like used, for example, in off-shore structures. According to the present invention there is provided a moving cradle system comprising a support beam having a platform arrangement suspended from each of its ends, bogey means attached to said support beam for enabling the support beam to run along a bracing member of a structure to be inspected and drive means for effecting movement of the support beam along said member. Preferably, each platform arrangement comprises three vertically spaced access platforms, Preferably also, said drive means includes a cable and pulley system operated by a pair of winches each located on a respective platform arrangement. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view schematically illustrating a moving cradle system made in accordance with the present invention; Fig. 2 is front elevational view of the system of Fig. 1; Fig. 3 is a top plan view of the system of Fig. 1; and Fig. 4 illustrates the cradle system of the invention running along a horizontal and an angled bracing member. Referring to the drawings, a moving cradle system comprises a cradle unit 1 having a support beam 10 from the ends of which are suspended respective platform arrangements 11 and 12. The support beam 10 is triangular in section and is of the welded lattice type such as to withstand the complexity of loads resulting from bending, compression and, in particular, torsion. Each platform arrangement has three access boxes the respective floors of which form vertically spaced horizontal platforms 11 a, 11 b and 11 c and 1 2a, 1 2b and 1 2c. More specifically, the access boxes which are hung from the support beam 10 each comprises welded structural steel frames, when assembled, create three levels of access each complete with handrails, toeboards and sliding ply support panels. As will be described below, each access box is fitted with respective air winches which work independenty of each other. Unlike conventional cradles, the unit will remain balanced when only one winch is operated. Intermediate the ends of the support beam 10 there is provided a hinged bogey comprising two pairs of downwardly extending support structures 13, 14, each structure carrying two rollers 15, 16 and 17, 1 8 respectively, adapted to engage a steel bracing member 20 straddled by the cradle and along which the cradle may run. The steel member 20 can be horizontal or inclined as illustrated in Fig. 3, the hinged bogey permitting the suspension of the platform arrangements 11, 1 2 on the support beam 10 to be such that the platforms ila, llb, llcand 12a, 12b, l2carealways horizontal. The support structure 1 3 comprises a first pair of arms 1 3a, 13b having respective ones of their ends connected together and hinged to the support beam at 33a, their respective remote ends carrying respective wheels 1 5, 1 6, and a second pair of arms 1 3c, 1 3d hinged to the support beam at 33b and again having their remote ends connected to the respective wheels 1 5, 1 6. The remote ends of the arms 13a, and 1 3c are connected to the remote ends of the arms 1 3b and 1 3d by a tie member 13e. In a similar manner, the support structure 14 comprises analogous arms 14a to 14e. In use, the hinged bogey is clamped to the support beam and tightened at the same angle to the horizontal as the bracing member 20 along which it runs thereby retaining the access platforms in a horizontal position. The wheels 1 5 to 1 8 enable the trolley to run along the bracing member 20 smoothly and accurately thus providing close access for inspection and maintenance personnel. The wheels 1 5 to 18 are made of polypropylene, have sealed bearing and are fitted with guards to protect them from blasting grit, paint spray, etc. To effect movement of the cradle unit 1 along the steel bracing member 20 and to effect lowering of the unit on to the member, the moving cradle system is provided with a cable/winch system which comprises pulleys 40, 41,42. 43 mounted on the support beam 10, cabling 60, 61 and a pair of air powered winches 50, 51 located one on each platform arrangement. The whole system is suspended by a cable 22 fixed to two suitable spaced suspension points, the cable 22 engaging a wheeled trolley 21 fixed to the cross beam 10. There has thus been described a moving cradle system which is in the form of a personnel carrying cradle/trolley and designed primarily for inspection and maintenance work on off-shore streel structures but its use is not limited to these structures. The system is self-driven, powered and controlled from the platforms. It has a capability for vertical and horizontal movement anywhere in the vertical plane between two fixed suspension points. It can operate on both horizontal and angled members, the design of the beam being such that the floors in the platforms are always in the horizontal plane. Modifications and improvements may be incorporated without departing from the scope of the invention. CLAIMS

1. A moving cradle system comprising a support beam having a platform arrangement suspended from each of its ends, bogey means attached to said support beam for enabling the support beam to run along a bracing member of a structure to be inspected and drive means for effecting movement of the support beam along said member.

2. A moving cradle system as claimed in claim 1 wherein said support beam is in the form of a welded lattice member having a triangular section.

3. A moving cradle system as claimed in either claim 1 or 2 wherein said bogey means is hingedly attached to said support beam enabling the platform arrangement to be maintained in a horizontal plane.

4. A moving cradle system as claimed in any preceding claim wherein said bogey means comprises a number of arms hingedly fixed to said support beam and carrying wheels at their remote ends.

5. A moving cradle system as claimed in any preceding claim wherein the platform arrangement comprises a plurality of access boxes the respective floors of which form vertically spaced horizontal platforms.

6. A moving cradle system as claimed in claim 5 wherein said access boxes are in the form of welded structural steel frames.

7. A moving cradle system as claimed in any preceding claim wherein said support beam is provided with a wheeled trolley suspended by cables on a structure to be inspected.

8. A moving cradle system as claimed in any preceding claim wherein said drive means includes a cable and pulley system operated by a pair of air winches each located on a respective platform arrangement.

9. A moving cradle system substantially as hereinbefore described with reference to the accompanying drawings.