Self-propelled Platform Tower Having Mechanical And Hydraulic Supporting Means

Abstract

This invention relates to a deck or work platform of improved design supported so that it can be moved into a selected direction over the ground, both under water and on land. It may be used on the sea bottom, particularly at an offshore location and it may also be used on tundra, muskeg, swampy locations and the like. The improved tower of the present invention has combined mechanical and hydraulic support means and normally the hydraulic means would be used when moving the tower from one place to another while the mechanical support means would ordinarily be used after the tower was in a desired location.

Description

SUMMARY OF THE INVENTION

Exploitation of various materials which were found offshore, such as minerals, oil, deposits from oyster shells and the like, are gaining importance. The provision of a suitable platform or work surface has been met in various ways, usually be erecting a structure in one location. Proposals had been made for portable platforms but they were not fully satisfactory. In the prior art structures some could only move in a single direction or two directions at right angles to each other. If one wishes to move such a platform at an angle, it is necessary to float the platform to the desired new angle. Other prior art structures did allow an angular movement but they achieve this either by employing circular roller tracks or a central roller pad, both of which are expensive and required having specially built parts. In my previous U.S. Pat. No. 3,612,210, I described and claimed an improved self-propelled platform tower which could not only move forward and back and sideways, but which could also be moved in an angular direction. My invention provided a simple, rugged corner structure which enabled the platform to be moved at an angle.

Although this represented a substantial improvement over prior art structures, the structure was originally designed to employ hydraulic cylinders exclusively for raising and lowering the legs. Hydraulic lifts have many obvious advantages since they are simple, inexpensive structures, capable of exerting enormous pressures. However, hydraulic lifts do suffer from one defect, namely, that it is almost impossible to provide a hydraulic lift without some slight leakage. This presents no problem when the hydraulic mechanism is actively in use such as when the platform is being moved from one location to another. However, if the platform is to be left at a location for a substantial length of time, some means must be provided for maintaining pressure in the system to make up for any small leaks. This is particularly important if the platform is located on irregular ground, which is usually the case. Thus, if the platform is to be left in place for days, weeks or even longer, the hydraulic support structure becomes undesirable because of the necessity of monitering and maintaining the oil pressure. A mechanical system would overcome these defects in the hydraulic system since a mechanical system can be locked in place for an indefinite period of time. However, it is difficult and expensive to devise a mechanical system which is strong enough to handle the enormous loads which are involved in moving a platform from place-to-place.

In accordance with the present invention, a dual system is provided which has all of the advantages and none of the disadvantages of a purely hydraulic system. Hydraulics are used for moving the platform from place-to-place but after the platform is once in place, the mechanical system can be brought into play to support the structure so that it is not necessary to maintain oil pressure when the platform is left for long periods of time. Furthermore, since the mechanical and hydraulic systems are independent, the maximum raise can be substantially greater than that provided by the hydraulic cylinder alone. Thus, in many instances, the mechanical system is made strong enough to raise the tower if this is found necessary and serves to extend the range through which the legs can be moved.

It is therefore an object of the present invention to provide a structure of generally improved design over my previous patented structure U.S. Pat. No. 3,612,201 wherein a combination of mechanical and hydraulic extension means is employed in the legs of the platform.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings forming part of this application:

FIG. 1 is a perspective view of a moveable platform embodying the present invention.

FIG. 2 is a side view of such a platform showing the operation of moving the platform from place-to-place.

FIG. 3 is a section through one of the legs of the moveable platform.

FIG. 4 is a section on the line 4--4 of FIG. 3.

FIG. 5 is an enlarged partial section with some parts cut away of the mechanical drive mechanism.

FIG. 6 is a plan view of the platform.

FIG. 7 is a diagrammatic view showing how the platform and table assembly can be skewed for angular movement.

FIG. 8 is a section on the line 8--8 of FIG. 6.

FIG. 9 is an enlarged section of a horizontal support assembly used in the platform.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with this invention, I provide a work deck or platform 7. This is generally rectangular in shape and provides a solid working surface to support suitable tools such as a derrick. Mounted on the surface of the deck is a control panel 9 which includes suitable controls for operation of hydraulic pump 11 which is utilized to supply pressure for the operation of various hydraulic rams as will be described. Control panel 9 also serves to control the motors of the mechanical systems.

In accordance with this invention, I provide a first set of vertical corner posts 12 at each of the four corners of the work deck. Each corner post includes and supports a moveable ground engaging member 13. Each ground engaging member can be selectively raised and lowered with respect to its supporting corner post by means later described in detail.

In accordance with this invention, I provide a rectangular frame 18 which is selectively moveable in a fore and aft direction as indicated by arrows 15 with respect to the deck, in a direction transverse to the deck as indicated by arrows 20 and at angles thereto as indicated by arrows 16. The frame 18 is made up of longitudinal members 19 and transverse members 21 joined together to form a rectangular frame. At each corner of the frame, a second set of four corner posts 22 is provided. These may be similar in construction to each of the four corner posts previously described and which are attached to the deck 7; each of the corner posts 22 supports a moveable ground engaging member 23 which is raised and lowered by the means later described.

At each corner of the deck 7, a rectangular frame, generally indicated at 26, is mounted, this having an upper channel rail 27 and a lower channel rail 28, supported on one side by corner post 12 and at the other end by the vertical member 29. The horizontal members 19 are supported in a hexagonal frame 31 (FIG. 9) having vertically extending rollers 32 mounted therein on opposite sides to support one of the members 19. At the top and bottom of each member 19, tracks 33 are provided and are engaged with horizontal rollers 34. At the top and bottom of the hexagonal frame 31, rollers 36 ride in the channel rails 27 and 28 to permit the hexagonal frame and the supported frame 18 to be moved transversely of the deck by the hydraulic ram, generally indicated at 39. To move the frame 18 fore and aft, another ram structure, generally indicated at 37, is mounted on the underside of each of the frame members 19 as appears in FIG. 6, each of the piston rods 38 being connected to one of the corner posts 12. To move at an angle, both sets of rams would be actuated to skew the platform as is shown in FIG. 7. The hexagonal frame members 31 can be employed at all four corners, or only two need be used, one on each end.

The supporting leg structure which constitutes the gist of the present invention will now be described in detail. One is shown in FIGS. 3, 4, and 5, and, since all eight of the legs are of substantially the same structure, only one will be described in detail. Each leg includes a tubular member 40, having a telescoping leg 42 slideably mounted therein with a foot plate 44. Hydraulic cylinder 46 is attached to leg 42 by means of connection 48, the hydraulic cylinder 46 having the usual piston 50 and piston rod 52, the top of the piston rod being attached by connection 54 to the cylinder 40. Oil through lines 56 is supplied from pump 11.

Cylinder 40 is provided The a plurality of racks 58, suitably four in number, each of which passes through a slot 60 in a keeper assembly 62. By passing through slot 60, cylinder 40 is prevented from turning but may slide up and down in corner assembly 62. It will be understood that the keeper 62 can form a corner of the work deck 7 or the frame member 18. Mounted in slot 61 in keeper 62 is a ring gear 66 having concave spur teeth 68 on its outer surface and a helical thread 70 on its inner surface. Thread 70 meshes with he racks 58. A worm gear 72 driven by a motor 74 meshes with the spur teeth 68. Thus, by turning gear 66, cylinder 40 is moved up and down through the keeper 62. It will thus be seen that the foot 44 can be raised or lowered either by the action of the hydraulic cylinder 46 or by turning gear 66.

The method by which the device crawls from one location to the other is shown in FIG. 2. There the feet 13 of platform 7 are in contact with the surface of the ground or a sea bottom as at 17. The feet 23 of the frame member 18 are now raised, and by the action of the cylinders 39 or 37 or a combination of both sets of cylinders, the frame is moved in a desired direction which may be forward, aft, sideways, or at an angle to a position such as that shown in dot dash lines in FIG. 2. The feet 23 of the frame are now lowered to support the entire structure and now the platform feet are raised; the frame can remain stationary while the platform 7 is moved in a desired direction, again by the use of the cylinders 37 or 39 or a combination thereof. These operations are, of course, repeated until a desired location is reached.

As has been previously stated, one of the advantages of the present invention is that it combines the best features of the mechanical and hydraulic systems. Thus, in moving from one location to another, the mechanical system need not be actuated, and all of the vertical movement is accomplished by use of the hydraulic system. Then when the platform is in the desired position, the mechanical system can be used to extend the legs while simultaneously withdrawing them by means of the hydraulic system so that finally the bottom of the cylinder 40 rests on the foot member 44 as is shown in FIG. 1. When the parts are in this position, the platform will be stable because of the large amount of friction in the mechanical system and the hydraulic system can be completely deactivated.

In many instances, by using the hydraulic system to move the platform vertically and using the mechanical system merely to hold the platform in place once the desired location is established, the mechanical system can be made much weaker than the hydraulic system, thus effecting a substantial saving in cost. Further, it is not necessary that all eight legs have both mechanical and hydraulic systems. Thus, the platform legs might be fitted with combined mechanical and hydraulic legs, while the frame had only hydraulic legs. On the other hand, in some instances it is desirable to make the mechanical system strong enough to elevate the platform, in which case one obtains the advantage of much greater extension of the legs than could be obtained with either the hydraulic or the mechanical system alone, permitting operation over a wider range of terrain.

Although a specific mechanical method of raising and lowering the legs has been described, other mechanical methods may be substituted. For instance, the legs can be threaded and rotated in fixed nuts to raise and lower the legs.

From the foregoing, I believe it will be apparent that I have provided a novel and simple moveable platform construction which can be moved fore and aft and transversely by hydraulic means over a sea bottom which may be of quite an uneven contour.

Claims

I claim:

1. In a moveable platform comprising:

a. a flat generally horizontal rectangular deck,

b. a first set of four corner posts provided at each corner of said deck,

c. each of said first corner posts including and supporting a movable ground engaging member therein,

d. means for raising and lowering each movable ground engaging member (c) with respect to its supporting corner posts,

e. a rectangular frame,

f. means supporting said frame on said deck for movement selectively fore and aft, transversely and angularly to said deck,

g. means for moving said frame selectively in each such direction,

h. a second set of four corner posts provided at each corner of said frame,

i. each of said second corner posts including and supporting a movable ground engaging member therein,

j. means for raising and lowering each movable ground engaging member (i) with respect to its supporting corner posts,

k. said means (j) for at least one of said sets of corner posts comprising a first system for extending and retracting each ground engaging member hydraulically and a second system for extending and retracting each ground engaging member mechanically.

2. The structure of claim 1 wherein both the first and second sets of corner posts are provided with both mechanical and hydraulic systems.

3. The platform of claim 1 wherein each of the supporting corner posts includes the following structure:

a. a cylinder mounted to move up and down in a keeper structure,

b. a telescoping leg mounted to move up and down in said cylinder,

c. hydraulic means adapted to move said leg up and down in said cylinder, and

d. mechanical means adapted to move said cylinder up and down in said keeper structure.

4. The structure of claim 3 wherein said mechanical means includes:

a. at least one rack mounted on the outside of said cylinder,

b. a ring gear having an internal helical thread meshing with said rack, and

c. means for turning said ring gear to move the cylinder up and down.