GB2028236A

GB2028236A - Displacement apparatus for a construction supportable by a spud

Info

Publication number: GB2028236A
Application number: GB7926985A
Authority: GB
Original assignee: MARINE STRUCTURE CONSULTANTS BV; Marine Structure Consultants MSC BV
Current assignee: MARINE STRUCTURE CONSULTANTS BV; GustoMSC BV
Priority date: 1978-08-08
Filing date: 1979-08-02
Publication date: 1980-03-05
Also published as: DE2931976A1; JPS5526400A; GB2028236B; NL168288C; BE878119A; NL168288B; NL7808305A

Abstract

In an apparatus for displacing a construction such as a work platform or dredger both along and transversely to a spud (1), the spud (1) extends through a frame construction (7, 8, 9) and guides the frame construction in the longitudinal direction and the frame construction is connected to the displaceable construction by means of at least three link rods (11) extending substantially parallel to the direction of the spud. Vertical movement is caused by hydraulic jacks 6 attached to a frame 7 and yokes 4 carrying releasable lock pins for engaging the spud 1. Horizontal movement is caused on hydraulic jack attached to frame 9. <IMAGE>

Description

SPECIFICATION Displacement apparatus for a construction supportable by a spud The invention relates to a displacement apparatus destined for a construction supportable by a spud and provided with both a mechanism for displacing the construction along the spud and with a mechanism for displacing the construction substantially transversely to the spud, the spud extending through a frame construction guiding same in longitudinal direction.

Such constructions are applied e.g. in working platforms displaceable above water and in dredging vessels fitted with one or more spud anchors. In working platforms use is often made therefor of working platform parts movable relatively to each other in the horizontal plane, in which parts each time one or more spuds or legs are accommodated which are displaceable upwards and downwards.

Dredging vessels with spud anchors are mostly provided with spud carriages movable relatively to the vessel and guided thereby.

It is the object of the invention to substantially simplify the displacement apparatus by replacing the often elaborate and complicated mobile or movable constructions by a simple and relatively inexpensive linkage.

This is achieved according to the invention by a displacement apparatus of the above described type in that the frame construction is connected through at least three link rods extending substantially ip the spud direction to the construction to be displaced.

The mechanism obtained in accordance with the invention is sufficiently provided with a single displacement means, e.g. a hydraulic cylinder, for performing a required displacement in substantially horizontal direction.

If in accordance with a preferred embodiment of the invention, the link rods are positioned in accordance with the longitudinal sides of a prism, it is achieved that the frame constructions and thereby also the stud is displaced during a transverse displacement parallel to itself.

In accordance with a further embodiment of the invention it is preferable that the link rods half-way through the maximum transverse displacement between spud and supportable construction extend in vertical direction. It is thus achieved that the vertical movement of the displaceable construction is minimized when the spud is stationary. This vertical movement may furthermore be entirely compensated by an opposite displacement of the lifting mechanism.

A slightly less dimensionally sensitive and hence more inexpensive displacement apparatus is obtained when the link rods are provided at both ends with ball joints. To prevent that as a result the frame construction and the spud will rotate above their longitudinal axis relative to the supportable construction, the supportable construction should be provided with guiding means for the spud in the displacement direction. However, this requires particular provisions on the displaceable construction and thus again entails tolerances of its own.Therefore from a viewpoint of loading and friction it is recommendable that at least two stabilization rods are present, the ends of which are connected pivotally about horizontal shafts perpendicular to the displacement direction on the one end to the construction and on the other end to the frame construction, said stabilization rods projected in a plane perpendicular to the displacement direction enclosing an angle to the link rods extending parallel in said plane.

If in accordance with still another embodiment of the invention the stabilization rods between their ends are provided with a joint having a shaft parallel to the displacement direction and fitted with means for controlled variation of their length, there is created the possibility to dispiace through variation of the length of the stabilization rods, the frame construction together with the spud transversely to the normal displacement direction. Possibly, depending on the design, also both directions of travel may be simultaneously executed so that movement in each direction is possible.

A particularly compact embodiment is obtained when the frame construction comprises an upper and a lower rectangular frame embracing and guiding the spud, which two frames are rigidly interconnected by a box-shaped construction, whereby adjacent the angular points of the upper frame four link rods are secured, the transverse displacement mechanism engages the lower frame and the longitudinal displacement mechanism is accommodated in the box-shaped construction. This geometrically simple construction, to be made from readily obtainable standard sections, has the additional advantage that the longitudinal displacement mechanism is present within a protective envelope.

In accordance with a further embodiment of the invention it is also preferable that two stabilization rods are present, of which each time the end coupled pivotally to the frame construction is rigidly connected each time to a link rod adjacent the upper frame in such a way that the centerlines of both rods intersect each other at the link pin of the link rod with the frame, whereby the two other link pins of the rods are co-extensive. Besides the saving of two links and a rectilinear movement of advance in a plane perpendicular to the longitudinal axes of the stabilization rods, this construction moreover provides an optimal starting point for realizing a displacement transversely to the normal dispiacement direction.

One embodiment of the displacement apparatus according to the invention will now be described, by way of example, with reference the accompanying drawings, wherein: Figure lisa cross-section of the displacement apparatus according to the invention on the line I-I in figure 2; Figure2 is a longitudinal section on the line ll-ll in figure 1; Figure 3 is a longitudinal section on the line Ill-Ill in figure 1; Figure 4 is a cross-section on the line IV-IV in figure 3; and Figure 5 shows on a reduced scale a construction supportable by a spud which by means of the displacement apparatus according to the invention is movable relatively to said spud.

In the drawing a spud 1 is shown which is adapted to support a construction 2. The construction 2 may be e.g. a working platform or a dredging vessel. The spud 1 has a rectangular cross-section, whereby two oppositely disposed sides are each provided with two rows of regularly spaced apart bores 3 adapted to co-act with pins 5 slidably accommodated in a yoke 4. Along each side of the spud 1 provided with bores 3 there is present a yoke 4 guided by said side.

Each yoke 4 is connected through two hydraulic cylinders 6 to a rectangular frame 7 entirely embracing the spud 1 and guidable along said spud. The frame 7 is rigidly connected through a rigid box-like construction 8 to a similar rectangular frame 9. On each of the four angular points of the frame 7 there is disposed an outwardly extending sheet-like ear 10.

On each of the ears 10 is attached the one end of a link rod 11 by means of preferably a ball joint 12. The other ends of the link rods 11 are pivoted to the construction 2, likewise preferably by means of ball joints 13. Two ears 14 are rigidly secured to two of the four rods 11, which ears 14 carry a linearjoint 15 and are each connected via said joints 15 to the one end of a stabilization rod 16, the other end of which is pivoted to the construction 2, preferably via ball joints 17. The frame 9 is pivoted to the one end of a hydraulic cylinder 18, the other end of which is coupled, in a manner not shown, pivotally to the construction 2.

The displacement of the spud 1 in its longitudinal direction relative to the construction 2 is effected by means of the hydraulic cylinders 6 which on the one end can be coupled via yokes 4 to pins from the spud 1 and on the other end are connected via the frame 7 and the link rods 11 to the construction 2. By alternately coupling the two yokes 4 to the spud 1 while operating the hydraulic cylinders 6 accordingly, the spud may be displaced in a continuous movement relative to the construction 2.

For displacing the spud 1 in transverse direction relative to the construction 2, reference may be made to figure 5. If the construction 2 is assumed to be free from a subjacent water surface, whereby the spud 1 makes contact with the bottom underneath said water surface, then, starting from the position shown by full lines the position drawn by dash-dot lines will be occupied by retracting the hydraulic cylinder 18. The construction 2 consequently has been displaced relative to the stationary spud 1 by means of swivelling of the link rods 11. If the construction 2 is a dredging vessel, then a second spud may be present which in principle need only be displaceable in longitudinal direction. During displacement of the construction 2 said second spud should be free from the bottom.After completed displacement of the construction, the second spud is brought in contact with the bottom and the spud 1 is raised. In such case, through telescoping the hydraulic cylinder 18, the spud 1 may be displaced relative to the construction 2 until the spud 1 is again in its starting position. In case the second spud is likewise provided with a transverse displacement mechanism, then a continuous displacement of the construction 2 is possible.

In case the construction 2 is a working platform, at least five spuds should be present, which may be brought upwards and downwards. At least three of the five spuds should be provided with a transverse displacement mechanism in order to enable a running movement of the working platform. The five spuds present should thereby be so distributed over the working platform that the centre of gravity thereof is always present within the triangle formed by three spuds making contact with the bottom.

An increase of the displacement possibilities of the above described construction is obtained when the stabilization rods 16 are provided with means for varying the length thereof. These means may be a spindle with swivel or hydraulic cylinder. Through these means a displacement produced transversely to the displacement may be effected by the hydraulic cylinder 18. By causing these movements to take place in combined and simultaneous relationship, a displacement in any direction is possible.

An enlargement of the maximum displacement to be effected with the hydraulic cylinder 18, may be obtained by making the distance seen in figure 2 between the joints 13 larger than that between the joints 12, likewise seen in figure 2. In that that spud 1 then obtains a fictive centre of rotation above the construction 2 and will tilt slightly, the step size is enlarged. However, additional moments will occur therein in favour of the tilted spud, so that this will be applicable only in special cases, e.g. in case of relatively short spud lengths.

In addition to the above described variants of the construction shown in the drawings, many other amendments are possible without departing from the scope of the invention. In this respect it may be considered inter alia a number of link rods deviating from four, a different longitudinal displacement mechanism for the spud, a spud having a crosssection deviating from a rectangle, a modified frame construction and a directly pivotable coupling of two or more stabilization rods to the frame construction, and application to columns, pillars or the like other than spuds for working platforms and dredging vessels.

Claims

1. A displacement apparatus destined for a construction supportable by a spud and provided both with a mechanism for displacing the construction along the spud and a mechanism for displacing the construction substantially transversely to the spud, said spud extending through a frame construction guiding same in longitudinal direction, characterized in that the frame construction is connected to the displaceable construction by means of at least three link rods extending substantially in the spud direction.

2. A displacement apparatus according to claim 1, characterized in that the link rods are positioned in accordance with the longitudinal sides of a prism.

3. A displacement apparatus according to claim 2, characterized in that the link rods half-way through the maximum transverse displacement between spud and supportable construction extend in vertical direction.

4. A displacement apparatus according to any one of the preceding claims, characterized in that the link rods are provided at both ends with ball joints.

5. A displacement apparatus according to claim 4, characterized in that at least two stabilization rods are present, the ends of which pivotable about horizontal shafts perpendicular to the displacement direction are connected on the one end to the construction and on the other end to the frame construction, the stabilization rods projected in a plane perpendicular to the displacement direction enclosing an angle to the link rods that extend parallel in said plane.

6. A displacement apparatus according to claim 5; characterized in that the stabilization rods between their ends are provided with a joint having a pin parallel to the displacement direction and provided with means for controllably varying their length.

7. A displacement apparatus acccording to any one of the preceding claims, characterized in that the frame construction comprises an upper and a lower rectangular frame embracing and guiding the spud, which two frames are rigidly interconnected by a box-like construction, whereby adjacent the angular points of the upper frame there are attached four link rods, with the transverse displacement mechanism engaging on the lowerframe while the longitudinal displacement mechanism is accommodated in the box-like construction.

8. A displacement apparatus according to claim 7, characterized in that a pair of stabilization rods are present, of which at least the end pivotally connected to the frame construction is rigidly connected each time to a link rod adjacent the upper frame in such a way that the axes of both rods intersect each other at the pivot pin of the link rod with the frame, the two other pivot pins of the rods being coextensive.

9. A diplacement apparatus substantially as hereinbefore described with reference to the accompanying drawings.

10. A construction supported by at least one spud and provided with displacement apparatus according to any preceding Claim.

11. The features as herein described, or their equivalents, in any novel selection.