EP0034672A1

EP0034672A1 - Column mounted crane

Info

Publication number: EP0034672A1
Application number: EP80300482A
Authority: EP
Inventors: John H. Hansen
Original assignee: Delong Corp
Current assignee: Delong Corp
Priority date: 1980-02-20
Filing date: 1980-02-20
Publication date: 1981-09-02

Abstract

A crane (28) is rotatably mounted on a base (26) which includes a jacking mechanism (30,32,38) adapted to surround and engage an upright foundation column for vertical adjustment thereon. A supporting leg of a self-elevating mobile marine platform is suitable for use as such a column for supporting the crane.

Description

COLUMN MOUNTED CRANE

This invention relates to a crane assembly mounted, or adapted to be mounted, to a column for revolving thereabout and for adjustment vertically thereon. The invention relates especially to a rotatable crane supported on a self-elevating.base that is mountable on a column for vertical movement thereon. More especially this invention relates to such a crane assembly wherein the column comprises a supporting leg for a mobile self-elevating offshore platform, although it will be realized that the crane assembly may be used with other columns for other uses.

BACKGROUND OF THE INVENTION

Mobile self-elevating offshore platforms, whether adapted for drilling for oil or gas or for construction or work purposes, almost always have need of a crane thereon. In the past many cranes used for such purpose have been of the conventional mobile type which move about on the platform deck on caterpillar-type tracks or on rubber-tired wheels. Such use of mobile cranes, however, requires heavy and expensive reinforcement of the platform deck areas on which the cranes travel. Further, deck space on such platforms available for crane travel is usually quite limited. Instead of a mobile crane, such platforms also frequently use a crane of fixed type mounted on a foundation, usually in the form of a tub or a pedestal. The fixed type crane obviously is limited to working only in a very distinct and restricted area. Further, the head room of both of the aforesaid mobile and fixed types of cranes is limited by boom length. By head room is meant the vertical distance'between the lowest load pick-up point and the maximum height to which a load may be raised by a crane. This is a limiting use factor for both of the aforesaid types of cranes irrespective of the weight of the load to be picked up.
Accordingly, it is an object of this invention to provide a crane assembly which can be mounted on any one of the supporting legs of a mobile self-elevating offshore platform, so that crane loads are imposed on such leg thus avoiding the necessity of reinforcing deck areas for a mobile crane or of providing a tub or pedestal foundation for a fixed crane.
It is another object of this invention to provide such a crane assembly wherein the base thereof comprises self-elevating means mountable to, movable vertically on, and readily removable from a supporting leg or column, thereby utilising existing platform structure for a crane foundation and also greatly increasing headroom over the usual limiting factor of boom length.
It is another object of the invention to provide such a crane assembly wherein the crane boom revolves about its supporting base.
It is a further object of this invention to provide such a crane assembly that is adapted to be mounted to and movable vertically on an upright column or tower for use in the erection of buildings, bridges, smokestacks or the like.
According to the invention a crane comprises self-elevating means (26) arranged to be mounted around, movable vertically on, and engageable with, an upright column (14) characterised by:- supporting ring means (40 ,42) mounted on the self-elevating means (26) for rotation about a vertical axis by an actuator (70); a crane boom (56) pivotally mounted (at 60) on the ring means; and an actuator (62) for the crane boom.
The invention may be carried into practice in various ways, and certain embodiments will now be described by way of example with reference to the accompanying drawings; in which

FIGURE 1 is an elevational view of a mobile self-elevating offshore platform having thereon a crane mounted on a base and a foundation in accordance with the principles of this invention.
FIGURE 2 is an enlarged fragmentary view of the crane shown in FIGURE 1.
FIGURE 3 is a fragmentary vertical sectional view taken substantially on line 3-3 of FIGURE 2; and
FIGURE 4 is a diagrammatic elevational view showing a crane mounted on a base and a foundation in accordance with the principles of this invention for use in the erection of a building.

Referring now to the drawings there is shown, in FIGURE 1, a mobile self-elevating marine platform 10 having a buoyant barge-like body 12 with a plurality of upright supporting legs 14 guided for vertical movement relative to the body. Jacking mechanisms 16 are connected to the body 12 above the deck 18, one for each supporting leg 14, and are engageable with such legs to selectively lift or lower the legs relative to the body, or when the legs are engaged with the marine bottom as shown, to raise or lower the body on the legs. The jacking mechanisms 16 illustrated in the drawings as exemplary of this invention, are of the so-called air jack type exemplified by the U.S.A. patent to Pointer, 2,775,869, granted January, 1st 195,7. It will be realised, however, that jacking mechanisms for use in this invention may be of the slip jack type, exemplified by the U.S.A. patent to Lucas, 2,841,961 granted July 8th, 1958, or of the so-called pin jack type, exemplified by the U.S.A. patent to Suderow, 2,822,670, granted February llth, 1958. All such jacking mechanisms, however, have the common components of an upper section 20 and a lower section 22 adapted to surround a supporting column or leg 14 and to be releasably engageable therewith. against vertical movement relative thereto, and power-operated means 24 interconnecting the two sections for selectively effecting vertical movement in either direction therebetween. Further, as illustrated herein the supporting legs 14 are in the form of so-called caissons, i.e., steel cylinders, frequently of the order of about six feet in . diameter, but it will be understood that other types of supporting legs, symmetrical in horizontal section, can be utilized for practicing this invention.
The base 26 for a crane 28 in accordance with this invention is illustrated, as aforesaid, as being a jacking mechanism of the type disclosed in the aforementioned Pointer patent. For use in this invention such mechanism constitutes a self-elevating base 26 mounted to one of the supporting legs 14 above the deck 18 of the body 12, and above the jacking mechanism 16 associated with such leg for lifting and lowering the latter relative to the body or lifting and lowering the body on the legs when the latter are engaged with the marine bottom as shown.
As shown best in FIGURE 3 of the drawings, the self-elevating crane base 26 includes upper and lower gripper sections 30 and 32, each in the form of a structural ring surrounding the leg 14 and movable vertically therealong. Each section 30 and 32 is provided on its inner side with one or more inwardly facing rigid annular channels 34. Disposed in each channel 34 is an inflatable annular tube 36 which, when inflated, is constricted into gripping engagement with the outer surface of the supporting leg 14 so as to fix the corresponding gripper section 30 or 32 against vertical movement relative to the leg. Connected to and between the upper and - lower gripper sections 30 and 32 are a plurality of pneumatic or hydraulic cylinder and piston combinations 38 constituting linear actuators. The majority of the cylinders 38 may be of a single acting construction, while a few, arranged symetrically about the leg 14, are of a double acting construction so as to be adapted not only to exert forces to move the two gripper sections 30 and 32 apart vertically, but also to exert forces to pull them together. As explained in detail in the aforementioned Pointer patent, the base 26 comprises a self-elevating mechanism which can be operated to move step-by-step vertically in either direction on the supporting leg 14 and while the base is at rest, the inflatable tubes 36 of either, and preferably both, gripper sections 30 and 32 may be energized or inflated to securely fasten the entire base to the supporting leg against vertical movement.
For use in this invention the aforedescribed crane-supporting base 26 is provided with rotating rings, one 40 mounted to the upper gripper structure section 30 and the other 42 mounted to the lower gripper structure section 32. Each ring 40 and 42 is angular in radial section having a flat horizontal portion 44 and an outer depending skirt 46. Supporting rollers 48 secured to the undersides of the horizontal portions 44 of the rings 40 and 42 ride on corresponding upwardly facing annular tracks 50 provided on top of each gripper section 30 and 32, while rollers 52 mounted on the inner sides of the ring skirts 46 engage outwardly-facing circumferential tracks 54 provided on the outer periphery of the sections.
Conventional structure (not shown) may be employed to prevent upward movements of the rings 40 and 42 relative to their respective tracks 50 and 54.
The rings 40 and 42 form a rotating support for crane structure which includes a conventional boom 56 having its inner end 58 connected to the lower ring 42, as at 60, for pivotal movement about a horizontal axis. Raising and lowering of the boom 56 about such horizontal axis may be effected by a pair of double-acting hydraulic cylinder and piston combinations 62 having the inner ends thereof pivotally connected, as at 64, to opposite sides of the upper ring 40 and the outer ends thereof pivotally connected, as at 66, to the boom 56 outwardly of its inner end 58. Rotation of the . crane 28 about the supporting leg 14 desirably is effected by power-operated means, such as a pinion gear 68 mounted on the lower ring 42 for rotation about a vertical axis, driven by a hydraulic motor 70, and meshing with gear teeth 72 mounted to the circumferential track 54 on the lower section 32 out of the way of the rollers 52.
The crane boom 56 has mounted thereon, adjacent its inner end 58, the usual winding drum 74, operated by an appropriate hydraulic motor (not shown). A cable 76 wound on the drum 74 is trained over a pulley 78 on the outer end of the boom 56, thence downwardly through the usual crown block 80 having a hook 82 and thence upwardly where the end of the cable 76 is fastened to the outer end of the boom, as at 84. Opposite the boom 56 the lower ring 42 is provided with an outwardly projecting frame 86 for supporting a counterweight 88 which may be shiftable radially by known load-sensitive mechanisms (not shown) to counter balance loads supported from the crane hook 82. Preferably, the counter weight 88 may include a hydraulic power unit (not shown) for operating the aforedescribed hydraulic motors. Of course, such motors may be electric rather than hydraulic and in that case, the counterweight may include an electric power unit.
An operator's cab 90 containing appropriate controls (not shown) for operating the aforedescribed motors preferably is mounted on the upper ring 40 facing the boom 56 and located, as is conventional, to one side of a vertical plane extending through the centerline of the boom and the axis of the ring 40 for better operator visability of loads supported from the crane hook 82. Appropriate controls for the jacking mechanism incorporated in the crane base 26 also may be located in the cab 90 or, if preferred, located on the deck 18.
It will be seen that in operation the crane base 26 can be secured at any height desired along the supporting leg 14, and if more "headroom" is desired, the base may be elevated by its jacking mechanism to any desired convenient height.
Usually, a mobile marine platform of the type described herein is towed from one location to another with the legs 14 elevated.and held up by the jacks 16, so as not to engage the marine bottom. During such a tow the entire crane assembly 28 may be left in place on its foundation leg 14 or, if desired, the assembly may be lifted off its foundation leg and placed on the deck 18 of the body 12. In this same connection, the crane assembly 28 may be moved from one supporting leg 14 to another, as dictated by its required use. This may be done either by partial disassembly, i.e., removing the boom 56 and the counterweight 88 from the base 26, or by lifting the entire crane assembly 28, including its base and counterweight, from its foundation leg 14 and installing it on another leg. This may be accomplished with an appropriate travelling crane (not shown) moving about on the deck 18 or with a crane (not shown) mounted on an adjacent barge (not shown).
Referring now to FIGURE 4 of the drawings, there is illustrated a use of this invention for construction work on land, such as constructing a building 92. For such use there is erected on the building site an appropriate upright column or tower 94 and a crane base 26 in accordance with this invention is mounted to the tower for self-elevation thereon. The manner of use-of a crane assembly 28 in accordance with this invention, for the erection of buildings, smokestacks, bridges, and the like, is self-evident. It is pointed out, however, that in use of this invention for building erection the entire crane assembly 28 progressively moves upwardly along the column 94, to which additional top sections can be added progressively as needed. Most cranes presently in use for building erection are mounted for rotation to the top of a tower-like structure, and such structure, together with crane, is moved progressively upwardly as a unit as the building becomes progressively higher. Exemplary of such conventional cranes are U.S. patents Nos. 1,788,451; 3,207,475; and 3,366,251. U.S. patent No. 3,789,565 discloses a crane structure rotatably mounted on a self-elevating base mounted to and movable vertically on vertical tracks affixed to the side of a tall building structure, e.g., a silo, chimney, or the like, for erecting the latter in segments. Such a base, however, requires the use of special tracks and the crane is not rotatable about the tall building. In fact, its rotation is restricted to a limited arc except when the base is at the upper end of the tracks.
A specific and preferred embodiment of the invention has been illustrated in the drawings and described in detail above. It will be realized, however, that there can be various modifications incorporating the broad principles of the invention. For example, the crane structure has been illustrated and described as being attached to rotating rings 40 and 42 on the upper and lower sections 30 and 32 of the crane base 26. Either one of the sections 30 or 32, however, preferably the upper, may be of sufficient vertical extent for attachment of the entire crane structure thereto rather than to both sections. In such event, both the inner end 58 of the crane boom 56, as well as its raising and lowering cylinders 62, will be pivotally connected to rotating rings secured to the one section, and the lower of such rings may have the framework 86 and counterweight 88 supported thereon. In such event the rotating ring on the other section of the base 26 would be eliminated.
The invention has also been described with reference to a base embodying a general type of jacking mechanism having upper and lower holding means movable relative to each other by power-operated means. It will be seen, however, that the principles of the invention can be utilized with other types of self-elevating jacking mechanisms that are movable vertically on a foundation column, for example rack and pinion type jacking mechanisms. In order to permit the crane to revolve properly about the column, however, the column preferably should be symmetrical in horizontal section with the jacking mechanism engageable therewith symmetrically thereabout. For example, the column can be circular, square, or in the shape of an isosceles triangle.
It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the specific embodiment shown and described is susceptible to modification without departure from the principles of the invention. Hence, the invention encompasses all modifications within the spirit and scope of the following claims..

Claims

1. A crane comprising self-elevating means (26) arranged to be mounted around, movable vertically on, and engageable with, an upright column (14); characterised by:- supporting ring_' means (40,42) mounted on the self-elevating means (26) for rotation about a vertical axis by an actuator (70); a crane boom (56) pivotally mounted (at 60) on the ring means; and an actuator (62) for the crane boom.

2. A crane as claimed in Claim 1 including a counterweight (88) mounted to the ring means opposite the crane boom.

3. A crane as claimed in Claim 1 or Claim 2 including an operator's cab (90) mounted to the ring means offset laterally from the centerline of the crane boom.

4. A crane as claimed in any of Claims 1-3 in which the self-elevating means includes power operated upper and lower.holding means (30,32) each releasably engageable with the column against vertical movement relative thereto, and actuators (38) for effecting relative vertical movement selectively in either direction between said upper and said lower holding means.

5. A crane as defined in Claim 4 in which the ring means includes an upper ring (40) mounted on the upper holding means (30) and a lower ring (42) mounted to the lower holding means (32), and wherein the inner end of the crane boom is pivotally mounted on the lower ring and the crane actuator (62) is connected between the crane boom and the upper ring.

6. A crane as claimed in Claim 4 or Claim 5 wherein each holding means includes a pneumatic clamp ring adapted to surround the column.

7. A crane as claimed in Claim 6 in which each pneumatic clamp ring comprises an inflatable annular clamping member.

8. A crane as claimed in any preceding claim with the self-elevating means mounted around an upright, cylindrical or other, column (14) for example a tower (94)-for erecting a building.

9. A crane as claimed in any of Claims 1-7 in combination with a multi-leg platform (12) having jacks (16) connecting the legs with the platform, the self-elevating means being mounted along the platform and around one supporting legs which constitutes the column.

10. A crane and platform combination as claimed in Claim 9 in which the platform can float.