NL1041774B1

NL1041774B1 - Foldable staircase.

Info

Publication number: NL1041774B1
Application number: NL1041774A
Authority: NL
Inventors: Cornelis Rietema Klaas
Original assignee: Cornelis Rietema Klaas
Priority date: 2016-03-22
Filing date: 2016-03-22
Publication date: 2017-10-05

Abstract

it is an objective of the present invention to provide a staircase comprising stairs that enable bridging a significant height difference. The staircase according to the present invention, also referred to as stairs or stair sections, comprises at least two interconnected elongated articulated structures,. The staircase has a landing between each stair section as is required by health and safety regulations. The first stair section comprises mounting means at its first end and a hinge mechanism at its second end which provides a hinged connection with the first end of the second stair section. This assembly provides for a foldable staircase. The mounting means can comprise means which either can engage rotatably with a fixed counterpart or rigidly with a rotatable counterpart, providing a turntable which allows the first stair section to rotate around its first end both in a horizontal and a vertical plane. In an embodiment each stair section can bridge a height difference of maximum 4 meters.

Description

FOLDABLE STAIRCASE

FIELD OF THE INVENTION

The invention relates to offshore operations in general, more specifically to a staircase for the transfer of people between a fixed platform and a mobile platform which are situated at a distance from each other and at a different height.

BACKGROUND OF THE INVENTION

The invention relates to offshore operations whereby people have to be transferred between a fixed platform and a second mobile platform which are situated at a distance from each other and at a different height. For example, the first platform is a permanent offshore drilling platform and the second platform a jack-up drilling barge that temporarily rises above the water level on retractable legs. Often there is a height difference between the platforms that need to be bridged, and additionally the difference in height may change during the course of time through the settling of the lowered retractable legs into the sea bed.

Existing types of staircases are temporary and constructed on site, on the highest platform, often from the drilling platform: a climbing tower is built using scaffolding or staircase structure on the lowest platform, from which a gangway is laid to the other platform. The scaffolding or staircase is often craned over from the jack-up barge and taken away again on departure. This is labour-intensive and relatively unsafe and a crane must be available to transfer the material. Finally, the last people to dismantle the climbing tower must be transferred safely using a man cage on the crane. These requirements cause delays in the final stages of arrival and departure of the drilling barge.

The Dutch patent NL1039328 discloses a gangway that eliminates some shortcomings of earlier gangways and earlier modes of transferring people. Among the advantages of the gangway proposed by that Dutch patent is the fact that its support frame may be mounted in or on a container. Another advantage is the freedom of movement of the gangway. However, this gangway according to the prior art also has some drawbacks.

SUMMARY OF THE INVENTION

It is therefore an objective of the present invention to provide a staircase comprising stairs that enable bridging a significant height difference. The staircase according to the present invention, also referred to as stairs or stair sections, comprises at least two interconnected elongated articulated structures,. The staircase has a landing between each stair section as is required by health and safety regulations. The first stair section comprises mounting means at its first end and a hinge mechanism at its second end which provides a hinged connection with the first end of the second stair section. This assembly provides for a foldable staircase. The mounting means can comprise means which either can engage rotatably with a fixed counterpart or rigidly with a rotatable counterpart, providing a turntable which allows the first stair section to rotate around its first end both in a horizontal and a vertical plane. In an embodiment each stair section can bridge a height difference of maximum 4 meters.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which: - FIG. 1 is a schematic side view of an embodiment of the foldable staircase according to the invention in the unfolded operational state; FIG. 2 is a schematic perspective front view of an embodiment of the foldable staircase according to the invention in the unfolded operational state; FIG. 3 is a schematic side view of an embodiment of the foldable staircase according to the invention in the stowed state; FIG. 4 is a schematic perspective view of an embodiment of the foldable staircase according to the invention in the stowed state; FIG. 5 is a schematic back view of the turntable and top section of the staircase according to the invention.

Identical or similar parts have been designated with the identical or similar reference numbers in all drawings.

DETAILED DESCRIPTION OF THE INVENTION

The foldable staircase according to the invention provides a quick and cost effective solution for obtaining a ready to use staircase between two objects with a difference in height. In addition, the staircase according to the invention has a modest foot print while stowed. The staircase is mounted in a container or on a container base. Auxiliary equipment, such as for example an hydraulic power pack and a control panel for the operation of the staircase may also be located in this container or on this container base. FIG. 1 is a schematic side view of an embodiment of the staircase according to the invention in its unfolded or extended state, which is best viewed in combination with FIG. 2. FIG. 2 is a schematic perspective front view of the embodiment of the unfolded foldable staircase as shown in FIG. 1. In this embodiment the staircase comprises essentially three stair sections 1, 2 and 3, each of them comprising essentially one flight of stairs and a landing 4a, 4b or 4c at their upper end. The first stair section 1 has a longer landing 4a than the landings of the second and the third stair section. The first end or upper end of the first stair section 1, being the end comprising the landing 4a is connected to turntable engagement means 5 enabling hinge-like relative movements about a generally horizontal axis or generally horizontal axes driven by a slewing drive 8. In an embodiment the turntable comprises at least one slewing drive 6 for rotation of the turntable about an essentially vertical axis.

The turntable, is mounted on or includes a sub bottom frame 7. In an embodiment the turntable sub bottom frame 7 is mounted in a container or on a container base and does not only allow (sliding) movements in the longitudinal direction of the container, i.e. movement in an essentially horizontal direction. The invention also includes embodiments in which the turntable can be adjusted in a vertical direction.

The landing 4a of the first stair section 1 has to be long enough to allow the sub bottom frame of the turntable to move without being hindered by the inclined back of the first stair section 1.

In the embodiment shown in FIG. 1 and FIG. 2 the hinge connection between the first stair section 1 and the turntable engagement means 5 comprise at least one slewing drive 8.

The second or lower end of the first stair section 1 is connected to the landing 4b at the first or upper end of the second stair section 2 for hinge-like relative movement about a generally horizontal axis or generally horizontal axes. This hinge connection between the first stair section 1 and the second stair section 2 comprises at least one hydraulic or electric slewing drive 9 for the staircase folding and unfolding movements. The rotational axis of this hinge connection is located essentially at a position within the length of the landing 4b, perpendicularly to the longitudinal direction of the landing. When the stair sections are rotated into the operational position, all sections will be locked mechanically. The connection between the first stair section and the turntable will be locked close to the slewing drive 8. The connection between the first stair section and the second stair section will be locked in the vicinity of the slewing drive 9. The turntable will also be locked to prevent rotation around the essentially vertical axis of the slewing drive 6.

In the embodiment of the staircase according to the invention shown in FIG. 1 the second or lower end of the second stair section 2 is connected to the landing 4c at the first or upper end of the third stair section 3 for hinge-like relative movement about a generally horizontal axis or generally horizontal axes. This hinge connection between the second stair section 2 and the third stair section 3 comprises at least one hydraulic or electric slewing drive 10. The rotational axis of this hinge connection is located essentially at a position within the length of the landing 4c; perpendicularly to the longitudinal direction of the landing. The position of the rotational axis of the hinge connection between the second stair section 2 and the third section 3 located within landing 4c may, and is likely to, be different relative to the length of the landing as compared to the position of the rotational axis of the hinge connection in the landing 4b between the first stair section 1 and the second stair section 2. Apart from differences in the position of the rotational axis of two hinging landings within the same staircase, the positions may also vary from one embodiment of the staircase to another. The connection between the second stair section and the third stair section will be locked above the slewing drive 10. The locking of the connections between the staircase sections 1, 2 and 3 and/or between the first staircase section and the turntable may comprise a manually, hydraulically or electrically operated locking mechanism, for example a locking pin.

The differences in the positioning of the rotational axis of the hinge connection within the landings between the first and second stair section on the one hand and the second and third stair section on the other hand, which are created to achieve a more compact folding of the staircase assembly, may hereinafter also be referred to as differentiated hinged landings. It should be understood that the term differentiated hinged landing also covers any other suitable hinged connection that achieves the goal of having a compact staircase in the folded or stowed state and will therefore be within the scope of the invention.

The embodiment of the third stair section 3 as shown in FIG. 1 and FIG. 2 comprises engagement means 11 at its second or lower end in order to allow it to engage with a fourth stair section 12, hereinafter also referred to as a height adjustment section 12. At the lower end of the height adjustment section a detachable unit with one or more hydraulically operated support legs may be installed. The hydraulically operated support leg or legs exert a permanent upward force on the free end of the staircase assembly if the adjustment section 12 is attached, preferably rigidly, to the third stair section through the engagement means 11. This force ensures stability of the staircase and prevents it from dancing due to external forces such as for example the wind force. The staircase according to the invention comprises embodiments with a variety of combinations of heights of stair sections including the height of the height adjustment section 12. The heights of these sections can be altered by adding or removing individual steps of the stairs. In this way the staircase represents a modular system which can bridge any desired height difference. Depending on the height difference which has to be bridged embodiments of the staircase assembly that is actually used may comprise two stair sections 1 and 2 or three stair sections 1, 2 and 3 or four stair sections 1, 2, 3 and 12. If the height adjustment section 12 is not used the hydraulically operated support legs may be attached to the end of the stair section that comprises the free end of the staircase.

The invention comprises controls which enable mutual balancing of the load exerted by the hydraulically operated support legs of the height adjustment section 12 and the load and movement of the slewing drives of the staircase assembly. As explained earlier, in the operational state the stair sections are locked mechanically. The lowest stair section end, also referred to as the free end of the staircase assembly, will have a load controlled leg support to keep the full stair case in a fixed position. In the unfolded operational state of the staircase the connection between the first stair section 1 and the turntable engagement means 5 is locked at the slewing drive 8 and the turntable is also locked mechanically to disable rotation in an essentially horizontal plane. In this mode the support leg or legs at the lowest end of the staircase assembly exert a dynamic load in order to create stability.

When the height difference that has to be bridged by the staircase is such that the adjustment section does not have to be installed, the hydraulically operated support legs can be attached to the second end of the third stair section 3.

Based on regulatory requirements each stair section between two landings may bridge a height difference of maximum 4 meters. FIG. 3 is a schematic side view of an embodiment of the foldable staircase according to the invention in the stowed state. The drawing shows that the differentiated hinged landing connections assure that the stair sections fold closely together, thereby limiting the length and height of the space occupied by the staircase in the stowed or folded state. FIG. 4 is a schematic perspective view of an embodiment of the foldable staircase according to the invention in the stowed state. The invention includes embodiments of the foldable staircase, whereby the staircase can be rotated fully, both horizontally and vertically while in the folded state. FIG. 5 is a schematic back view of the turntable and top section of the staircase according to the invention, with a clear view of the slidable sub bottom frame 7.

While the attached drawings show embodiments of the staircase according to the invention in which the turntable is positioned on the highest platform, the staircase may also be positioned in the opposite direction, i.e. with the turntable on the lowest platform and the free end extending to the highest platform. In the latter case the free end will essentially be the highest end of the staircase.

The invention includes any embodiment of the foldable staircase with a staircase that is suitable for industrial application. In order to obtain a staircase with a high strength and stiffness while having a relatively low weight, a truss structure seems to be a good option for the staircase.

It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Claims

A device for bridging by persons a height difference between two objects located in proximity to one another, the device being connected at a first end to a turntable rotatable substantially about a vertical axis, characterized in that the device comprises at least two comprises stair sections (1,2) provided at a first end with a platform (4a, 4b), the first stair section (1) being rotatable at the first end with the aid of a hydraulically or electrically driven sprocket bearing (8) about a substantially horizontal axis connected to the turntable.

Device according to claim 1, characterized in that the turntable comprises a toothed wheel bearing (6) for rotation about a substantially vertical axis.

Device according to claim 1 or 2, characterized in that the device comprises a third stair section (3).

Device according to claim 3, characterized in that the first stair section (1) at the second end is substantially pivotally connected in a vertical plane to the landing (4b) of the second stair section (2) and in that the second stair section ( 2) at the second end is hingedly connected to the platform (4c) of the third stair section (3), the connection between the first and second stair section and the connection between the second and third stair section each having a hydraulically or electrically driven sprocket bearing (9) , 10).

Device according to one or more of the preceding claims, characterized in that the device comprises one or more differentiated hinged platforms (4b, 4c) for the purpose of being able to collapse the device more compactly.

Device according to one or more of the preceding claims, characterized in that the device comprises a fitting piece (12).

Device as claimed in one or more of the foregoing claims, characterized in that the staircase parts are secured in the unfolded state by means of a manually, hydraulically or electrically operable locking pin.

Device according to one or more of the preceding claims, characterized in that the turntable is secured by means of a manually, hydraulically or electrically operated locking pin.

Device according to one or more of the preceding claims, characterized in that the device comprises a hydraulically or electrically driven punch at the free end.

Device according to one or more of the preceding claims, characterized in that the device comprises a control system that controls the hydraulic or electrical control of the stamp.

Device according to one or more of the preceding claims, characterized in that the device is arranged on or in a container.

Device according to claim 11, characterized in that the turntable of the device is arranged so as to be movable in horizontal and / or vertical direction on a base frame (7) placed on or in a container.

Device according to claim 11 or 12, characterized in that the hydraulic unit and / or the control panel of the device are arranged in the container.

Device as claimed in one or more of the foregoing claims, characterized in that the third step part comprises engagement means (11) for substantially rigid but releasable engagement of the fitting piece (12).

Device according to one or more of the preceding claims, characterized in that the stair parts (1, 2, 3) and the fitting piece (12) are adjustable by coupling or uncoupling one or more stair steps.

Device as claimed in one or more of the foregoing claims, characterized in that one of the objects located in the vicinity of each other comprises a fixed offshore installation.