GB1594211A

GB1594211A - Access apparatus

Info

Publication number: GB1594211A
Application number: GB49190/76A
Authority: GB
Original assignee: John Laing Services Ltd
Current assignee: John Laing Services Ltd
Priority date: 1976-11-25
Filing date: 1976-11-25
Publication date: 1981-07-30
Also published as: ZA777003B

Description

(54) ACCESS APPARATUS (71) We, JOHN LAING SERVICES LIM ITED, a British Company, of 133 139, Page Street, London NW7, 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: This invention relates to self propelled access and treatment apparatus which is particularly suitable for use in obtaining access to the sides of a vessel in a dry dock in order, for example, to clean the sides of the vessel with a high pressure spray or to paint the sides of the vessel, although the use of the apparatus is not limited to this application.

Known access apparatus which is employed for this purpose suffers from the disadvantage that it must be supplied continuously from an external source with materials such as water and paint and with power as it moves along the side of a dock which may be five hundred metres in length.

It is thus normal for further apparatus, providing the supply of power and materials to be arranged along each side of a dock, thereby occupying space and reducing the amount of space available for a vessel in the dock and for manoeuvring the access apparatus between a side of a vessel and a respective side of the dock. The apparatus normally used is also expensive to install and maintain. Furthermore, the supply of electrical power to the access equipment as it moves continuously along the side of a dock introduces problems of insulation which, in the environment of a dock, are greater than they may be in some other environments.

Apparatus in accordance with the present invention is comparatively simple, may be completely self contained and can be used conveniently in existing docks where there is limited space.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a side view of an apparatus and a section through a part of a dock; Figure 2 shows a front view of the apparatus shown in Figure 1; Figure 3 is a side elevation of part of a paint spraying apparatus; Figure 4 is a part section on the line A A of Figure 3; Figure 5 is a partly sectioned side elevation of a further embodiment; and Figure 6 is a part section on the line A A of Figure 5.

Referring to the drawings, there is shown in Figures 1 and 2 one side 1 of a dock with a ledge 2 near to the bottom of the side of the dock arranged to provide vertical support for access equipment and a portion 3 extending from a surface 4 near to the top of side 1 of the dock. The portion 3 extending from above the surface of the dock provides horizontal support at 5 and 6 for access equipment. The ledge 2, near to the bottom of the side 1 of the dock, provides a support for a rail 7.

Access equipment for use in the dock includes a support structure 8 having an "A" frame 9, the legs of the "A" frame being supported on respective bogies 10 and 11, each bogie having flanged wheels 12 running on the support rail 7. The wheels 12 of the bogies 10 and 11 are driven by respective hydraulic motors 13 and 14 to drive the structure along the dock. The upper part of the support structure 8 carries, at 15, housings for rubber-tyred wheels which run on the surfaces 5 and 6 and provide lateral support for the structure.

The housings 15 can be demounted from the support structure 8 to allow the use of a hauling-in trolley running on the portion 3 forming a rail and extending above the dock surround.

The upper part of the support structure 8 also carried material storage housings at 17 and 18. At 17, actually within the support structure 8, there is, in the particular embodiment, a water tank. The housing 18 accommodates containers for treatment materials, for example grit, solvent and paint. as well as pressure cylinders and blower machinery for use in handling these materials.

A machine house 19 is mounted above the material storage housings on the outer ring 20 of a slewing mechanism. whose relatively fixed inner gear is attached to the top of the support structure 8. The house 19 is thus rotatable about a vertical axis 21 The house 19 carries a jib arm 22, which, in the embodiment described is 30 metres long, and is pivotable about a horizontal axis passing through the house 19 under the control of a luffing mechanism. In the machine house 19, there are hydraulically driven motors for operating the luffing and slewing gear, a diesel generator to provide electrical power, hydraulic pumps and diesel fuel supplies, among other things.

At the front end of the machine house 19 there is a control cabin 23 from which a view of the length of the jib arm 22 can be obtained.

The jib arm 22 is pivotable about a horizontal axis 24 and extends beyond the axis 24 and 25, the part 25 being fitted with counter-weights to counterbalance the arm 22.

At the other end 26 of the jib arm 22. there is an open working platform 27. The floor 28 of the platform 27 is kept in the horizontal plane, irrespective of the angle of the arm 22, by means of an arm 29 connected to a hydraulic ram on the arm 22, in a well known manner. A set of controls is provided at 30 in addition to the controls in the cabin 23. The platform 27 is rotatable about a vertical axis 31 by means of hydraulic rams (not shown). A spray head 32 is shown mounted on the platform 27. The head 32 may be used, for example, in washing or painting the hull of a vessel. Wheels 33, attached to the platform 27 can run on the hull of a vessel and maintain the spray heads at a constant distance from the hull.

It will be appreciated that hand held treatment apparatus could be employed. The treatment materials, for example grit, water or paint, are fed to the platform 27 from the house 18 via flexible supply lines (not shown). In operation the rotating portion of the apparatus, namely house 19 and arm 22, can be slewed hydraulically through an angle of 180 . The pre-determined torque exerted on the jib arm 22 by the slipping action of the fluid drive automatically keeps the working platform and spray heads at the required distance from the ship's side. The hydraulic drive also reduces the possibility of shock being transmitted to the main structure from the jib arm 22 in windy conditions.A hydraulic brake mechanism operated from the control cabin is fitied to the slewing mechanism and a locking device is incorpo- rated in the brake so that the revolving apparatus can be locked in position when the dock arm is not in use.

The jib arm 22 is rotatable about the axis 24 to enable the platform 27 to be moved from the top to the bottom of the hull of a vessel and since the platform 27 is rotatable about the vertical axis 31, it is possible to move the platform 27 over the hull of the vessel while maintaining it at constant distance from the hull.

In some situations, it may be desirable that there should be no contact between any part of the platform 27 and the hull of the vessel being treated.

Platform arrangements which are suitable for use in this situation will now be described with reference to Figures 3 and 4, which show the end of a jib 22 pivotally coupled to a platform 27 via a bracket 33. The bracket 33 pivots about a horizontal axis 34 and can be rotated about the axis 34 by means of an arm 35. The platform 27 is carried upon the bracket 33 via a slewing ring 36 which is rotatable (by means not shown) about a vertical axis 36a to enable the platform 27 to be slewed in accordance with the movement of the jib arm 22 and the shape of the hull of the vessel to maintain the position of the platform relative to the hull of the vessel.

The platform 27 carries a paint spray unit 37 and wheel units 38 which incorporate plenum chambers 39. The paint spray unit 37 and the wheel units 38 are urged, in operation, towards the hull 40 of a vessel by the action of the jib 22 as a result of a constant torque which is applied to the jib 22 and controlled from the power cabin 23 shown in Figures 1 and 2. Compressed air from housing 18 of Figure 1 is forced into the plenum chambers 39 via pipes 41 and the force exerted by the compressed air entering the plenum chambers 39 reacts against the force applied to the wheel units 38 by the jib 22 to cause the wheel units 38 to be- lifted off the hull 10 of the vessel. The amount by which the wheel units 38 are lifted off the hull 10 of the vessel is determined by the volume, velocity and pressure of the air supplied to the plenum chambers 39 via the pipes 41 and thus also determines the distance by which the spray unit 37 is spaced from the hull 10 during operation.

Referring to Figures 5 and 6, illustrating yet another embodiment of an arrangement for spacing a platform from a hull, there are shown an end of a jib 22 which is controlled from a power cabin 23 as shown in Figures 1 and 2 and which is capable of horizontal and vertical movement. A bracket 42 is pivotally connected to the end of the jib 22 about a horizontal axis 43 and a slewing ring 44 carrying a platform 27 is pivotally mounted upon the bracket 42 in such a way that it is rotatable with the slewing ring about a vertical axis 45. the platform 27 carries a paint spray unit 46 which incorporates paint spray nozzles 47, a plenum chamber 48 and wheel units 49.The paint spray unit 46 and the wheel units 49 are urged, in operation, towards the hull 50 of a vessel by the action of the jib 22 as a result of a constant torque which is applied to the jib and controlled from the power cabin 23 shown in Figures 1 and 2. Compressed air is forced into the plenum chamber 48 via pipes 51 and the force exerted by the compressed air entering the plenum chamber 48 reacts against the force applied to the wheel units 49 by the jib 22 to cause the wheel units 49 to be lifted off the hull 50 of the ship. The amount by which the wheel units 49 are lifted of the hull of the ship is determined by the volume, velocity and pressure of the air supplied to the plenum chamber 48 via the pipes 51 producing a cushion effect and thus also determines the distance by which the spray unit 46 is spaced from the hull 50 during operation.

The chamber 48 is so constructed that the reaction between the air in the chamber and the hull 50 facilitates a loss-minimized, controlled, paint spraying process. Other treatments, for example blasting with grit and washing with water can be made from the platform 27 in a similar way.

It will be appreciated that, although the invention has been described, by way of example, with reference to particular embodiments, variations and modifications can be made within the scope of the invention

Claims

claimed. For example, a materials storage housing may be fixed relative to and therefore rotatable with the machine housing. In another embodiment, the materials storage housing is rotatable about a vertical axis and the jib is rotatable vertically about the materials storage housing. Other forms of boom than jib 22 can be employed. For example, a telescopic boom can be used which, in its retracted condition, can be raised or lowered more easily and can carry heavier loads than can the single lattice structure. It will also be understood that the housing 19 could be rotated through 3605, the apparatus being employed on a dock wall separating two docks to operate in either of the docks merely by the rotation of the housing 19 through 180 The arrangement described has the advantage over known arrangements that it is not necessary to have high pressure fluid supplied through long lengths of flexible tubing or to have power cables suspended flexibly along the length of the side of the dock as is the case in certain previously proposed arrangements. Other power transmission means than hydraulic fluid could be used to rotate the jib 22 and the platform 27, and it will be appreciated that other means than piston and cylinder arrangements could be used for driving these parts of the apparatus. WHAT WE CLAIM IS:

1. Self propelled access apparatus including a carriage arranged to carry a vertical load, a materials storage structure, a drive machinery housing, the carriage supporting the materials storage structure and the drive machinery housing, a jib, the jib being rotatable with respect to both a horizontal axis and a vertical axis under the control of the drive machinery, and a working platform, the working platform being carried by the jib and being rotatable with respect to the jib about both a second vertical axis and a second horizontal axis, the materials storage structure being adapted to carry materials for use at the working platform and materials for use in operating the apparatus to cause movement of the carriage, the jib and the working platform, thereby rendering the apparatus self contained.

2. Apparatus as claimed in claim I including first and second wheels mounted upon the materials storage structure, the wheels being arranged to carry loads in first and second horizontal opposing directions.

3. Apparatus as claimed in either claim 1 or claim 2 wherein the carriage includes first and second bogies and first and second hydraulic motors arranged to drive the bogies respectively.

4. Apparatus as claimed in any one of the preceding claims including means to maintain the working platform at a distance from a surface.

5. Apparatus as claimed in claim 4 wherein the means to maintain the working platform at a distance from the surface includes means to provide a cushion of air between the platform and the surface.

6. Apparatus as claimed in claim 5 including a plurality of spraying nozzles mounted on the platform, the spraying nozzles being surrounded by the cushion of air.

7. Apparatus as claimed in any one of the preceding claims wherein the materials storage structure is fixed relative to the carriage, including a housing containing the drive machinery, the said housing being rotatable with respect to a vertical axis, the jib being carried by the housing and being rotatable about a horizontal axis with respect to the housing.

8. Self propelled access and treatment apparatus substantially as described herein with reference to Figs. I and 2, Figs. 1, 2, 3 and 4, or Figs. 1, 2, 5 and 6 of the accompanying drawings.