SUSPENDED SYSTEM FOR SUPPORTING A PERSON AND METHOD FOR USING SAME, E.G. IN CONFINED SPACES

The present invention relates to the field of rope access or industrial climbing techniques - "abseiling" in their simplest form. These techniques generally employ lightweight sports climbing and caving ropes and equipment of limited strength to suspend a person from a suspension facility such as a pneumatic or electric hoist, e.g. a winch. The person generally wears a harness which is attached to a climbing rope of the suspension facility, which is subsequently unrolled for lowering the person. Thereby, rope access techniques enable the person to reach difficult access areas without the need for scaffolding, for example to perform inspection, repair, cleaning or constructive activities - e.g. welding. Such difficult areas are, for example, surfaces of walls of enclosures, e.g. interior walls. Such enclosures may be confined spaces such as silos, tanks - e.g. for storing natural gas, cooling towers - e.g. as commonly employed in nuclear power plants, and a tower or monopile foundation of a wind turbine. Other applications are areas underneath bridges, areas of, e.g. high rise, building facades, or of other high wall surfaces, e.g. of interior wall surfaces manufacturing halls or warehouses. Use in plants or real estate is also envisaged. Furthermore, rescue operations may be performed by means rope access techniques - for example wherein caregivers are lowered into a confined space where their help is needed.

Reaching particular areas may require, in addition to the vertical distance over which the person is lowered, bridging a horizontal distance from a certain location of a suspension to a supporting location for the person, such that the person can reach the area, for example such that the person is horizontally less than an arm length away from the area. For example, when rope access is employed for inspection of a cylindrically shaped silo or tank, any suspension is often only possible through a manhole centrally arranged in a ceiling of the silo or tank, whereas the person performing the suspension needs to be within reach of the circumferential side wall at a horizontal distance from the manhole, and thus, the suspension. The horizontal distance to be bridged by the person to reach the side wall thus substantially corresponds to the radius of the silo or tank, which is typically around 5-10 meters.

Suspended structures for supporting persons are e.g. known from GB2311321 and US5301770. Both systems are to be employed as walkways, wherein the persons can walk over the structure to bridge a horizontal distance. GB2311321 discloses a modular access work platform which is capable of being suspended, comprising multiple segments which can be assembled together on the spot by suspended persons employing rope access.

US5301770 discloses a moveable platform which is capable of being suspended in a digestion tank from a hydraulic or electric hoist provided centrally at the top of the tank, wherein the platform can be extended horizontally towards the walls of the tank.

The present invention provides a system, suitable for supporting a person horizontally spaced from a suspension of the system, according to claim 1.

Contrary to the prior art wherein the supporting platforms extend horizontally, the system according to the invention comprises a V-shaped rigid support structure. The legs of the V- shape are formed by two elongate arms. These arms have outer, free ends, which define therebetween a length of the support structure. Thus, longitudinal directions of the system runs along the length of the support structure. The elongate arms extend upwardly slanted from respective inner ends thereof, which are located in a longitudinally central section of the support structure, outwardly in longitudinally opposite directions to the respective outer, free ends, of the arms. Thus, outward directions of the system run longitudinally away from the longitudinal center. In an embodiment, in the central section, the inner ends of the arms of the support structure are interconnected via a rigid connection member, e.g. a plate, e.g. made of steel.

The system furthermore comprises a span construction comprising tensile members, e.g. cables. Each tensile member is configured to be loaded under tension. Each tensile member extends horizontally or upwardly slanted from a respective outer fixation point, which is located within an outwards section of one of the arms, to the central section. Thus, the tensile members each slant downwards from the central section towards the outer ends of the arms. In the central section, the tensile members are for example each fixed at inner fixation points to an upright stand extending upwardly, interconnecting the inner ends of the arms and the tensile members. Thus, each tensile member extends from the outer fixation point to the upright stand. In the same or another example the tensile members are interconnected, or integral with each other. For example a tensile member is in fact formed by one half of one and the same physical member, e.g. a cable, which runs from the outer end of one of the arms to the outer end of the other one of the arms - either with or without additionally being fixed in the central section to the optional upright stand. An attachment member, e.g. an eyelet, is arranged in the central section, and configured for engagement by a suspension facility, e.g. by a lifting device, e.g. a crane. Via the attachment member, the system is to be suspended system from the facility, e.g. via a lifting cable of the facility thereby supporting the weight of the system and any supported person by said suspension. Thus, the attachment member enables a suspension of the system in the longitudinal center thereof. The suspension facility may be a pneumatic hoist or an electric hoist, for example a power winch. A manual hoist system may also form the suspension facility. For example, the facility is a crane. The suspension facility may also be formed by a fixed element, e.g. complying with EN 795-B, for example a beam, e.g. an I-beam or a structural anchor, e.g. a tripod. For example, such fixed elements may already be present at or near the ceiling of an enclosed space, e.g. a factory, tank, or silo.

The system is configured to support the person at a supporting location along one of the arms, e.g. at the free outer end, thereof, while a counteractive, downwards counterforce is exerted on the system at a longitudinal side of the suspension that is opposite to the side at which the person is supported. In practice, this counterforce will be exerted on the other one of the arms, e.g. at or near the outer end thereof. Such counterforce is provided in order to counteract the force moment that is caused by the weight of the person relative to the suspension. The counterforce can be provided in a number of ways. For example it may be in the form of a counterweight, e.g. the weight of another person, the counterweight being supported by the other one of the arms, e.g. mounted thereto, or be an external pushing or pulling force. The system may comprise a counterweight support element configured to support the counterweight. The outer end of the other arm may for example be arranged against a ceiling of an enclosure to be inspected, which creates a downwards pushing force onto the other arm upon exertion of the force moment by the weight of the person, and/or a cable may be spanned between the other arm and a stationary point below the arm, e.g. the ground, which creates a downwards pulling force upon exertion of the force moment. Another exemplary possibility is to provide at the outer end of the other arm a contact surface for engaging an upright, e.g. vertical, wall of an enclosure to be inspected, wherein the contact surface is configured to, upon engagement of the wall, exert a frictional upwards counterforce on the wall such as to counteract the mentioned force moment caused by the weight of the person. Such contact surface may for example be established and adapted to the required counterforce by choice of material and/or texture of the surface. For example, one or more wheels at the outer end(s) may be provided with a rough outer contact surface.

When the system is suspended from the suspension facility, a downwards force on the respective arm of the system caused by the weight of the person, and the counterforce, cause in the tensile members a tensile stress, and in the arms predominantly a compressive stress. This is the result of the upwardly slanted orientation of the arms in the outward direction, combined with the horizontal or downwardly slanted tensile members in the outward direction. This arrangement makes that the forces compensating the weight of the person supported by a respective arm, decomposes in a tensile force in the tensile member(s) directed therefrom towards the central section, and a compressive force component with the same horizontal component in the arm. It is noted that the weight of the arms may already cause a pre-tension in the tensile members. A typical safe working load for the weight of the person is 200 kilograms.

The horizontal support structures without tensile members, as known from the prior art, are, predominantly, subjected to bending forces as a result of the weight of the person on the structure at a distance from the suspension. A capability of such straight structure to carry the weight, therefore results in requirements on the flexural strength, and therefore the yield strength of the material and/or the moment of inertia of the cross-section. Typically, this results in a heavy, voluminous, expensive construction with high-performance materials, typically steel.

The support structure of the present invention being predominantly being subjected to compressive forces whilst supporting the person, may result in a more favorable mechanical stress profile, and thus advantageously lower the demands on the materials and the spatial arrangement thereof. For example, the arms may be designed to the buckling strength instead of the yield strength - which makes that materials with lower yield strengths, and/or arrangements with lower moments of inertia in the cross-section, may be suitable for the arms as well. This may considerably reduce the weight and material use of the construction - which provides important advantages regarding transport and handling, but also in terms of the ecological footprint of the system as a result of a lower material use and easier production and transport to the location where the system is to be used.

For example, according to common practice, the activities requiring rope access are performed by a specialized company which owns the system and has the educated personnel for performing the activities. After a request, the system, and possibly the suspension facility, is transported over the road, for example in parts, and assembled and set up at the location where the activities are to be performed. This generally involves carrying the parts of the support structure on the shoulders of workers, and assembling these on the spot, often at great height. After finishing the activities, the process has to be performed again in reverse order. A lighter construction may in this practice, save a considerable amount of time and physical effort - and therefore, costs. For example, with lighter and/or smaller parts, carrying and positioning requires less effort and improves handleability and maneuverability thereof. A lighter construction may pose less stringent requirements on the suspension facility, so that, for example, more types of winches and/or winches with less power, and/or structural elements would be suitable to serve as such. Furthermore, the system could be suitable for use at more places, for example places where a heavier I more voluminous structure can practically not be suspended.

It is envisaged that the system is suspended without any additional upwards support from below, e.g. any support onto the bottom of the enclosure. Thus, substantially the whole weight of the system - and in use, therefore also any thereby supported persons - is supported by means of the suspension only. Accordingly, the system is envisaged as being configured for such support via suspension only. This includes for example that the system is devoid of any stand onto which it is to be supported onto the floor.

In relation to the invention, the term longitudinally central section should be taken to mean a section which is horizontally limited within a central region. For example, the central region does not necessarily contain a midline of the system. It should at least be possible to suspend the system within the central section such that the arms extend in the intended upwardly slanted orientation.

The suspension of the system in the central section may have several advantages. For example, when the system is used in a rotationally symmetric enclosure, such as a cylindrical tank or silo, e.g. for inspecting the inner surface of the side wall, the system may be supported by the facility from above in the enclosure, through the ceiling, by means of one compact, centralized suspension. During the activity, the system may simply be swiveled around the vertical axis through the attachment member - and thus, the suspension, for reaching a horizontally adjacent part of the side wall by the supported person(s). After all, with a constant radius, the horizontal distance from the suspension to the wall is also constant over the angular range with respect to the suspension.

Throughout the disclosure, the orientational and directional terms such as ‘vertical’, ‘lateral’, and ‘horizontal’ are defined considering a suspended system. Of course, when in another orientation than when suspended, these terms will no longer apply - however, these terms should in relation such differently oriented system be considered as well as if it were indeed suspended. Preferably, the arms of the support structure have a similar angle with the vertical and/or substantially the same length, e.g. the system is substantially symmetrical with respect to a vertical axis through the attachment member - and thus, the suspension. This may be advantageous in terms of stability when suspended from the facility, and furthermore provides possibilities of use by either one two persons at a time - each being supported by a respective arm. However, it is noted that embodiments wherein the arms have a different length and/or define a different angle with the vertical, are also within the scope of the present invention.

In an embodiment, a rigid upright stand of the system extends upwardly in the central section of the system, for providing fixation points in the central section for the span construction, in particular the tensile members between outwards sections of the arms and the central section. The upright stand is connected to the inner ends of the arms, and extends upwardly from these inner ends within the central section. The tensile members of the span construction extend from the respective outer fixation points to respective inner fixation points of the upright stand. The inner fixation points are at substantially the same height of the respective outer fixation point or higher, so that the tensile members extend substantially horizontally or upwardly slanted in the direction towards the central section.

In an embodiment, the attachment member is connected to or integral with the rigid upright stand, e.g. is provided at an upper end of the upright stand, e.g. directly above the connection of the tensile members of the span construction with the upright stand.

In an embodiment the upright stand comprises wings which extend outwardly in opposed lateral directions towards respective outer lateral ends at respective lateral sides of the support structure. The inner fixation points are provided at the outer ends, and the span construction comprises two or more tensile members for each arm, which extend from the outer section of the arm to each of the fixation points. The result is that the two or more tensile members of each arm define a horizontal angle between them, and, seen from above, define a triangle with the wings, which may provide advantages in terms of strength and stability.

In an embodiment the wings together form, viewed in a longitudinal direction of the system, a triangle pointing downwards towards the central section of the support structure, which may provide advantages in terms of strength and stability. In an embodiment the upright stand has a straight, vertical, lower portion and a triangularly shaped upper portion - the triangle pointing downwards. In an embodiment, the outer fixation point of one or more of the tensile members e.g. of all tensile members, is located at the free outer end, of the respective arm. The fixation at the outer end has the advantage that a downwards force exerted by the supported person, causes, at least predominantly, a compressive force in the arm over the whole length of the arm, i.e. up to the outer end. In an embodiment, the outer fixation point of one or more of the tensile members is located further inwards along the arm, but still within an outer section thereof, between around half of the length and the free outer end of the arm, for example in the outermost quarter, e.g. fifth, e.g. tenth, e.g. twentieth, of the arm.

In an embodiment, the span construction comprises two tensile members for each arm, running laterally adjacent one another from the outer section, e.g. outer free end, of the arm to the central section, e.g. to the upright stand. In an embodiment, the span construction comprises more than two tensile members for each arm. In an embodiment, the span construction comprises multiple tensile members for each arm, wherein the outer fixation points of the tensile members for each arm, are longitudinally spaced from one another, so as to each define a different angle with the respective arm.

In an embodiment, the span construction has exactly one tensile member for each arm. In an embodiment, the span construction has exactly one tensile member, extending between the outer sections, e.g. the free, outer ends, of the arms, and through the central section.

In an embodiment, one or both of the outer ends of the arms of the support structure are provided with one or more guiding members, e.g. one or more wheels, configured for engaging a surface and guide the outer ends along the surface in a direction perpendicular to the arms. For example, this direction may correspond to a tangential direction of the circle defined by a rotation of the system around a vertical axis through the suspension of the system, i.e. through the attachment member. As mentioned before, such rotational movement may be employed during use of the system, in order for the supported person to travel horizontally along an inner circumference of an enclosure.

In an embodiment, the system is adapted for use with rope access, the person being suspended from one of the arms underneath the supporting location via a climbing rope departing downwardly from the one of the arms at the supporting location. In an embodiment the system thereto comprises for one or both of the arms of the support structure, respective rope guides for guiding one or more climbing ropes, for example a main line and a back-up line, from an upper fixation point within or above the central section via the inner end of the respective arm, along the arm via the outer section, preferably the outer end, thereof downwards from the supporting location to a lower fixation point of a climbing harness of the person being suspended from the supporting location. In an embodiment, the system further comprises the climbing rope(s). For example, the climbing rope(s) extend from a supporting location downwards all the way to or near the ground, so that the suspended person can use rope access or abseiling techniques to descend and/or ascend. In an example, the climbing rope(s) may be connected, e.g. at the upper fixation point, to a winch for moving the suspended person upwards or downwards remotely e.g. when the person is in danger, e.g. for moving the person towards a door, e.g. combined with a vertical and/or horizontal movement of the system or the arm(s) thereof, e.g. a rotation of the system around the suspension, and/or a pivoting and/or extension movement of the arms. The upper fixation point within or above the central section may be external from the system, e.g. be part of the suspension facility or of a ceiling of an enclosure inside which the system is suspended. With the mentioned rope access techniques, the support of the person by one of the arms is thus established from above the person via the climbing rope(s). In case of support of the person by means of the suspension via the climbing rope(s), the mentioned supporting location is the location at which the climbing rope departs from the arm downwards to the person. For instance when used in a cylindrical enclosure, this supporting location is preferably at the outer, free end of the arm, so that the suspended person is horizontally closest to the inner circumference of the enclosure at which the activity, e.g. inspection, has to be performed by the person. Where a climbing rope is included, it is preferably according to the worldwide I RATA rope access standard and/or certified according to EN 1891-A.

In an embodiment the arms of the V-shaped support structure each define an acute angle with the vertical direction of around 45-85 degrees. For example the angle is around 60-85 degrees, e.g. around 75-85 degrees, e.g. around 80 degrees. A larger angle results in shorter arms to establish the same system length, i.e. for bridging the same horizontal distance from the suspension, and in a larger resultant tensile stress in the tensile members from supporting the person. The larger resultant tensile stress may e.g. be accommodated by providing more tensile members or providing a higher tensile strength.

In an embodiment the arms of the support structure are pivotable around a lateral pivot axis through the central section from an operational position of the support structure to a collapsed position of the support structure. In the operational position, the arms of the support structure each define a first, maximum acute angle with the vertical direction, e.g. of between 60 and 85 degrees, the support structure having the V-shape. In the collapsed position the arms of the support structure each define a second, minimum acute angle with the vertical direction. For example the arms are, when the system is suspended, substantially vertical in the collapsed position, e.g. so as to extend substantially along the upright stand. Herein, again, it must be noted that the positions are defined when considering a suspended state of the system - merely to indicate the orientations of its parts therein. In an embodiment the system further comprises one or more actuators, e.g. cylinders or electric motors, for driving a pivoting movement of the arms, around the lateral pivot axis between the operational position and the collapsed position of the support structure.

Providing the collapsed position in these embodiments, enables to arrange the system in a compact form with a reduced occupied space. In particular, when the system is to be used inside an enclosure, e.g. a tank or silo, wherein the insertion and removal of the system into and out of the enclosure should be accomplished through a manhole, the collapsed position may, in embodiments, enable the system to be maneuvered through the manhole in one piece. For example, after the insertion and prior to the use, the arms may be pivoted from the collapsed to the operational position. After the use and prior to the removal, the arms may be pivoted again from the operational position to the collapsed position. Such insertion in one piece, provides a significant improvement with respect to the prior art. As said, the conventional practice is to move any support structure inside an enclosure in parts, e.g. segments, and to assemble the parts inside the enclosure. An insertion in one piece, may save a considerable amount of time and physical effort. In other embodiments an insertion of the system in parts may be further facilitated by the collapsible property.

In an embodiment which may be collapsed and/or is built from multiple separate parts, e.g. including truss segments, the system may be suitable to be passed through a hole with an effective diameter of around 0.5 m, e.g. of 0.4 m, e.g. of 0.2 m, e.g. in an upper section of a silo, e.g. even in a side wall of an enclosure.

In an embodiment the system is adapted for use inside an enclosure, e.g. a confined space, e.g. a silo, the enclosure having a height and circumferential side, bottom and top walls with an inner surface, wherein the walls delimit an internal space of the enclosure. When the system is suspended inside the enclosure via the attachment member, the free outer ends each face opposite sides of the inner surface. The length of the support structure substantially corresponds to an internal horizontal dimension of the confined space, so that the inner surface is within reach of a person supported by one of the free outer end of one of the arms of the system suspended inside the enclosure, It is envisaged that the person is suspended underneath the supporting location, preferably at or near one of the outer ends of the arms, to perform work relating to the inner surface, e.g. inspection or cleaning work. The person can be lowered by lowering a larger length of rope underneath the supporting location, so that the person can progress to lower areas of the inner surface. Or, the suspended person can employ rope access climbing or abseiling techniques and/or a rope winch for ascending and descending. In this case, as mentioned before, both a main line and a back-up line may already run from the supporting location to the bottom of the enclosure. When combined with an advancing horizontal rotation of the system around the suspension of the system, the inner surface of the side wall can be reached by the person along a major part of, or the entire, height and inner circumference, e.g. a major part of the surface area of the inner surface, of the enclosure.

In an embodiment the arms of the support structure each have a length of 5-12 meters, e.g. of around 10 meters each. These embodiments would enable the horizontal distance which can be bridged by the supported person from the suspension to the outer end, to be for example up to 5-10 meters. As mentioned, this distance would correspond to the radius of a commonly used silo or tank - an envisaged application of the system - so that the person would be able to move from the suspension the inner surface of a side wall of the silo or tank, in particular to a supporting location at or near the outer end, within reach of the inner surface.

In an embodiment one or both of the arms of the support structure are extensible and retractable. For example, the arms are telescopically extensible and retractable. For example, segments of the arms may be slid alongside each other, or inside and outside each other. Alternatively, the arms may be articulated, with mutually pivoting segments. In an embodiment, the arms are retractable to 0.2-0.8 times, e.g. 0.5 times, a maximum length thereof. In an embodiment, the system further comprises one or more actuators, e.g. cylinders or electric motors, for driving a extending and retracting movement of the arm(s), between a retracted position and an extended position of the arm(s). These embodiments may be favorable considering compactness of the system, e.g. facilitating transportation, handleability, and insertion into and removal from an enclosure, but also in applications of the system where it is beneficial to vary the horizontal distance between the supporting location and the suspension. Such applications may for instance be inside an enclosure of which the cross-section of the internal space varies along the height, for instance an egg-shaped digestion tank or a frustoconically shaped foundation of a wind turbine. For instance, the person may be supported, e.g. standing on, or e.g. suspended via a climbing rope underneath, the support point at or near the outer free end in order to reach the inner surface of the enclosure, and as the process continues, progress upwards or downwards by lifting or lowering of the whole system, by the suspension facility. For instance, this lifting or lowering of the whole system may be done instead of, or in addition to, lifting or lowering the person itself when suspended underneath the supporting location. When the cross-section of the internal space is at the higher or lower height is larger or smaller, the lifting or lowering of the system may be accompanied, respectively, by an extension or retraction of the arm to increase or decrease the horizontal distance to the suspension of the system, so as to bring the supported person within reach of the inner surface again.

In an embodiment, one or both of the arms are constructed out of releasably interconnectable segments. In an embodiment combined wherein the support structure is collapsible, this may for instance enable a method wherein the support structure is transported in segments, and is assembled on the spot prior to suspension from the suspension facility, for example prior to insertion into an enclosure. For example, the segments may be 0.2-2.5 meters long. For example, segments may be 2, 1, 0.5 and/or 0.25 meters. The dimensions and weight of the segments may be designed to optimize handleability, by man and/or machine. For example, the dimensions and weight may be adjusted to international or national working standards and norms, e.g. to NIOSH, NEN-1005-2, and/or ISO-11228-1 , or similar standards and norms. For example, the segments may be designed to have a mass of at most 25 kg each. For example, one or more segments may be designed to have a mass of at most 23 kg, e.g. of at most 20 kg, e.g. of at most 15 kg, e.g. of at most 8 kg.

In an embodiment, one or both of the arms of the support structure is/are furthermore adapted for supporting a person from below on the arm. For example, the arm may be designed to facilitate walking over, and/or standing or sitting on the arm. When for example a person is to be suspended from the outer end of one of the arms, the person may have to firstly move along the arm to the outer end. In practice, this involves securing of the person to a climbing rope for safety purposes in case the person falls from the arm. E.g. for the same safety purposes, the movement of the person to the end may be facilitated by the design of the arm(s). For example, one or both of the arms may comprise a walkable surface, e.g. a longitudinal walkway, along the arm(s), and/or a platform and/or working cage and/or seat, e.g. at the outer end(s). For example, one or both arms may be provided with means for supporting multiple floor platforms. For example, it is envisaged that such floor platforms may be supported in between multiple of the systems suspended juxtaposed to one another, e.g. at a distance of 2-8 meters. Or, in case one or more additional arms are provided in addition to the two opposed, described arms, between the additional arm(s) and the described arm(s).

In an embodiment the arms of the support structure are embodied as truss structures, e.g. constructed at least of longitudinal outer main chords and a plurality of diagonal members laterally and vertically interconnecting the main chords. This embodiment may provide a favorable ratio of mechanical strength and stiffness properties to weight and/or volume and/or material use. Furthermore, truss structures and segments thereof are widely used and produced, and commercially available. This may provide the advantage, that in certain applications, the arms of the system may be assembled from parts which are available from suppliers close to the place of use - which may reduce the need for transportation thereof from more remote locations.

In an embodiment, one or more the arms of the support structure are pivotable about a pivot axis substantially parallel or corresponding to the vertical axis through the suspension. This embodiment may enable horizontal displacement of the supported person in a direction perpendicular to the arm.

In an embodiment the support structure is predominantly made of aluminum, e.g. the inner and outer ends of the arms, being made of steel, e.g. stainless steel. This embodiment may provide a favorable ratio of mechanical strength and stiffness properties to weight and/or volume and/or material use.

In an embodiment the system has a total weight of below 350 kg, e.g. below 300 kg, e.g. below 250 kg. Such an embodiment may provide advantages in terms of handleability and ease of transportation, e.g. footprint.

In an embodiment the tensile members are fiber ropes, e.g. made of ultra-high molecular weight polyethylene, e.g. braided fiber ropes. A particularly suitable fiber rope is, at the time of filing the application, sold under the trademark Dyneema®. Embodiments are also envisaged wherein the tensile members are cables made from another material, e.g. steel, or wherein the tensile members are embodied as tensile bars.

In an embodiment, the system comprises, vertically between the attachment member and the span connection points, a rotary bearing for enabling rotation of the support structure, the upright stand, and the span construction relative to the attachment member, and therefore, to the suspension of the system via the attachment member.

In an embodiment, the tensile members are designed to facilitate fall protection of a person supported on the support structure, which secures himself to the tensile member(s). The tensile members may in this embodiment be configured, in addition to supporting the arms of the support structure, to support the person from above e.g. in case the person falls from the support structure. The support may involve a downwards deformation of the tensile member - for example, the tensile member may be pulled into a V-shape as a consequence of the support. In an example, the tensile member is configured to absorb a peak load of multiple times a maximum reference weight of the person, for example multiple times 100-200kg, for example six times the maximum reference weight - since the climbing harness of the person will generally reduce the peak load to six times the weight of the person.

In an embodiment, the system is configured to absorb a peak load of multiple times a maximum weight of the person, for example multiple times 100-200kg, for example six times the maximum weight, at the outer end of each arm, or example involving a plastic deformation of the system. Tensile members may be stretched, arms and upright stand may be buckled.

The invention furthermore relates to a method for supporting a person horizontally spaced from a suspension of the system according to the invention. The method comprises suspending the system via the attachment member from a suspension facility, involving engagement by the facility of the attachment member. The method further comprises supporting the person at a supporting location along one of the arms, e.g. at the free outer end thereof, while providing a counteractive, downwards counterforce on the system at a longitudinal side of the suspension opposite to the supported person, e.g. on the other one of the arms.

In an embodiment, the supporting of the person is performed by suspending the person from the one of the arms underneath the supporting location, e.g. the supporting location corresponding to the free outer end of the one of the arms. In an embodiment the system adapted for facilitating rope access, such as specified in claim 8, and the method further comprises, prior to the suspending of the person, attaching the climbing rope departing from the arm to the lower fixation point of the climbing harness of the person.

In an embodiment, the system is collapsible, such as specified in claim 10, and the method further comprises, prior to at least the supporting of the person, unfolding the system from the collapsed position to the operational position.

In an embodiment, wherein the system is adapted for use inside an enclosure, such as specified in claim 19, wherein the system is suspended inside the enclosure so that the free outer ends each face opposite sides of the inner surface. In an embodiment, the method further comprises inserting the system into the enclosure. For example, the system is therein collapsible as described, and the unfolding, i.e. the pivoting of the arms from the collapsed to the operational position, is performed after the insertion.

In an embodiment the supporting location is located at the free outer end of the one of the arms.

In an embodiment the method further comprises an action relating to a surface within reach of the person suspended underneath the supporting location, e.g. at the free outer end, the action comprising inspecting the surface and/or cleaning the surface and/or performing maintenance on the surface and/or performing construction work on the surface.

In an embodiment the method comprises, after at least the suspending, causing a rotation of the system around a vertical axis through the suspension of the system via the attachment portion, for example by exerting a tangentially directed push-off force by the supported person against a surface within reach of the supported person. For example, as discussed, inside an enclosure, this may be an inner surface of a side wall of the enclosure.

The invention furthermore relates to a method for arranging a support structure in an enclosure, e.g. a confined space. The method comprises suspending the system via the attachment member from a suspension facility, involving engagement by the facility of the attachment member. The method further comprises supporting the person at a supporting location along one of the arms, e.g. at the free outer end thereof, while providing a counteractive, downwards counterforce on the system at a longitudinal side of the suspension opposite to the supported person, e.g. on the other one of the arms. The method further comprises inserting the system into the enclosure. For example, the system is therein collapsible as described, and the insertion is done while the support structure is in the collapsed position. An unfolding, i.e. the pivoting of the arms from the collapsed to the operational position, may subsequently be performed after the insertion.

It is noted that to this method, the beforementioned optional features in relation to the method for supporting a person, may also be applied.

The invention furthermore relates to a method for conducting an action in an enclosure, e.g. a confined space. The method comprises suspending the system via the attachment member from a suspension facility, involving engagement by the facility of the attachment member. The method further comprises supporting the person at a supporting location along one of the arms, e.g. at the free outer end thereof, while providing a counteractive, downwards counterforce on the system at a longitudinal side of the suspension opposite to the supported person, e.g. on the other one of the arms. The method further comprises conducting, by the supported person, an action relating to a surface within reach of the supported person, e.g. suspended underneath the supporting location, e.g. at the free outer end. In an embodiment the action comprising inspecting the surface and/or cleaning the surface and/or performing maintenance on the surface and/or performing construction work on the surface. In an embodiment the method comprises, after at least the suspending, causing a rotation of the system around a vertical axis through the suspension of the system via the attachment portion, for example by exerting a tangentially directed push-off force by the supported person against a surface within reach of the supported person. For example, as discussed, inside an enclosure, this may be an inner surface of a side wall of the enclosure.

It is noted that to this method, the beforementioned optional features in relation to the method for supporting a person, may also be applied.

The invention furthermore relates to a system for supporting a person horizontally spaced from a suspension of the system.

The system comprises a rigid support structure, comprising at least one elongate arm, having an outer, free end. The elongate arm extends upwardly slanted from an inner end thereof located in a suspension section of the system, outwardly to the outer free end of the arm.

The system comprises a span construction comprising one or more tensile members, e.g. one or more cables. Each tensile member extends from an outer fixation point within an outwards section of one of the at least one arm, horizontally or upwardly slanted to the suspension section.

The system comprises an attachment member, e.g. an eyelet, which is arranged in the suspension section, and is configured for engagement by a suspension facility for suspending the system from the facility, e.g. via a lifting cable thereof.

The system is configured to support the person at a supporting location along one of the at least one arm, e.g. at the free outer end, thereof, while a counteractive, downwards counterforce is exerted on the system at a longitudinal side of the suspension opposite to the supported person, e.g. on another one of the arms, if present. The counterforce may also be exerted by the weight of a counterweight, provided at the other longitudinal side of the suspension.

When the system is suspended from the suspension facility, a downwards force on the respective arm, of the system caused by the weight of the person causes in the tensile members extending between the arm and the suspension section, a tensile stress, and in the arm, predominantly a compressive stress.

In an embodiment, the at least one elongate arm consists of two elongate arms, which are preferably arranged in line with each other, each at an opposed longitudinal side of the suspension. Preferably both arms slant upwards in the outward direction from the suspension section, the tensile member(s) extending between the outer section thereof and the suspension section, so that the person can be supported on either one of the arms.

Embodiments are also envisaged with more than two arms, for example three arms, of which at least one slants upwards in the outward direction with tensile members extending between its outer section and the suspension section, for supporting the person on that arm.

It is noted that to this system, the herein mentioned optional features in relation to the system for supporting a person according to claim 1, may also be applied.

In all,, the invention thus relates to a system and its use, supporting a person horizontally spaced from a suspension of the system via an attachment member in a suspension section, e.g. a central section, of the system. Tensile members extending horizontally or at an obtuse angle with the suspension between an outward section of a respective supporting arm of the system, and the suspension section of the system establish that when the system is suspended, a downwards force on the respective arm caused by the weight of the person, and a counterforce on the other arm, cause in the tensile members a tensile stress, and in the arms predominantly a compressive stress.

The invention will now be described in relation to the appended figures. In the figures: figure 1 illustrates, in a perspective view, a system according to the invention, and a detail of an upright stand of the system, figures 2a-b illustrate, in respectively a top and lateral view, the system of figure 1 , and details of the inner and outer ends of the arms of the system, figure 3 illustrates, schematically, in a lateral view, the same system being used inside an enclosure, with rope access, figure 4 illustrates, schematically, in a lateral view, a balance of forces in the support of a person by the system during the same use in the enclosure, figure 5 illustrates, schematically, in a top view, the same use of the system inside the enclosure, and figure 6 illustrates, schematically, some details of the same use of the system.

The figures show an embodiment of a system 1 according to the invention, for supporting a person 80 horizontally spaced from a suspension of the system 1. Figures 3-6 illustrate the system 1 being suspended via attachment member 40, which is formed by an eyelet and indicated in the detail of figure 1.

In figure 1, the longitudinal directions DLN, the upper direction D _u , the downward direction DD, the inward direction Di, and the outward direction D _o in relation to the system are indicated, when the system is suspended via the attachment member 40.

The system 1 has a central section 2, indicated in figures 3, 4 and 6, which is formed by the section of the system that is located centrally in the longitudinal direction DLN.

The system 1 comprises a V-shaped rigid support structure 10. In the lateral views of figures 2b, 3, 4, and 6, the V-shape can be best distinguished. The legs of the V-shape are formed by two elongate arms 12,13 having outer, free ends 16,17. The free ends 16,17 define therebetween a length 10L of the support structure 10, see figure 2b. The elongate arms 12,13 have respective inner ends 14,15, which are located in the central section 2, see figures 2a-b. The inner ends are interconnected by a connection member in the form of a steel plate. To form the V-shape, the elongate arms 12,13 extend upwardly slanted from the respective inner ends 14,15 thereof outwardly in longitudinally opposite directions DLN to the respective outer, free ends 16,17 of the arms 12,13.

The system 1 further comprises a rigid upright stand 20 which is connected to the inner ends 14,15 via the connection member, i.e. the steel plate, and extends upwardly therefrom within the central section 2 of the system 1. See e.g. figure 1 and the detail thereof. The tensile members 31,32,33,34 extend from the respective outer fixation points to the upright stand 20, in particular to respective inner fixation points 35,36,37,38 of the upright stand 20 at substantially the same height of the respective outer fixation point. Thus, the tensile members 31,32,33,34 extend horizontally when the system 1 is suspended. The system 1 further comprises a span construction 30, which comprises four tensile members 31,32,33,34 in the form of one or more cables. The tensile members 31 and 32 each extend from a respective outer fixation point at the outer end 16 of the leftmost one of the arms 12 horizontally to a respective inner fixation point 35,36 within the central section 2. The tensile members 33 and 34 each extend from a respective outer fixation point at the outer end 17 of the rightmost one of the arms 13 horizontally to a respective inner fixation point 35,36 within the central section 2.

The attachment member 40, i.e. eyelet 40, is arranged in the longitudinally central section 2. It is configured for engagement by a suspension facility 70, e.g. by a lifting device, e.g. a crane, which is here only schematically represented, for suspending the system 1 from the facility 70 via a lifting cable 71 thereof. The suspension being located in the central section 2, makes that the central section 2 corresponds to a suspension section 2.

Figures 3, 4 and 6 illustrate that the system 1 is configured to support the person 80 at a supporting location along one of the arms 12,13. Here, the person 80 is supported at the free outer end 17 of the rightmost arm 13, in particular, underneath the supporting location via a climbing rope 61 from which the person 80 is suspended. The weight of the person 80 exerts a downward force Fw on the outer end at the supporting location. The system is configured to support the person 80 while a counteractive, downwards counterforce Fw is exerted on the system 1 at a longitudinal side of the suspension, i.e., of the attachment member 40, that is opposite to the longitudinal side at which the person 80 is supported, namely, on the outer end 16 of the leftmost one of the arms 12.

When the system 1 is suspended from the suspension facility 70, the downwards force Fw on the respective arm 13 of the system 1 caused by the weight of the person 80, and the counterforce Fw on the other arm 12, cause in the tensile members 31 ,32,33,34 a tensile stress, and in the arms 12,13 predominantly a compressive stress. To illustrate this, in figure 4, an example balance of forces at each of the outer ends 16 and 17 is shown. The downward force Fw causes an upward vertical force component in the arm 12, and at the same time a horizontal tensile force FT in the tensile members 33,34 to counteract the force moment caused by Fw around the inner end 15 of the arm 13, the tensile members 33,34 being configured for being loaded with tension. The horizontal tensile force FT is counteracted by a horizontal force component in the arm 12. Thus, arm 12 is subjected predominantly to a compressive force Fc resulting from FT and Fw. It is noted herein, that the force balance is significantly simplified, and provided merely for illustrating the working principle of the invention. For example, the weight of the arms 12,13 is left out here, however, may in practice cause a pre-tensioning of the tensile members 31 ,32,33,34.

In the shown system, the outer fixation point of each of the tensile members 31 ,32,33,34 is located at the free outer end 16,17 of the respective arm 12,13. Embodiments are however envisaged, wherein the outer fixation points of the tensile members that are connected to the same arm, are spaced apart in the longitudinal direction DLN.

As in particular follows from the detail of the upright stand in figure 1 , the attachment member 40 is connected to or integral with the rigid upright stand 20 at an upper end of the upright stand 20, directly above the inner fixation points 35,36,37,38 of the tensile members 31 ,32,33,34 of the span construction 30 at which these are connected with the upright stand 20.

Referring in particular to figure 1 and figure 2a, the upright stand 20 comprises wings 21 ,22 extending outwardly in opposed lateral directions DLT towards respective outer, lateral ends 23,24 at respective lateral sides of the support structure 10. The inner fixation points 35,36,37,38 are provided at the outer lateral ends 23,24 and the span construction comprises two or more tensile members for each arm 12,13, which extend to each of the inner fixation points 35,36,37,38. As a result, the tensile members 31 and 32 of the leftmost arm 12, and the tensile members 33 and 34 of the rightmost arm 13, define between them a horizontal angle at the outer end. The tensile members at either side define a triangle between them and the wings 21 ,22, seen in a top view, e.g. figure 2a.

Furthermore, the wings 21 ,22 themselves are shaped to together form, viewed in a longitudinal direction DLN of the system as in the detail of figure 1 , a triangle pointing downwards towards the interconnected inner ends 14,15 of the support structure.

The shown system 1 is adapted for use inside an enclosure, e.g. a confined space, e.g. a silo. The system 1 is shown being used inside an enclosure 90, namely, a silo, in figures 3-6. The silo 90 has a height 90H and circumferential side, bottom and top walls 91 with an inner surface 92. The walls 91 delimit an internal space of the silo 90, wherein when the system 1 is suspended inside the enclosure 90 via the attachment member 40, the free outer ends 16,17 each face opposite sides of the inner surface 92. The length 10L of the support structure 10 substantially corresponds to the internal diameter of the silo 90, so that the inner surface 92 of the side wall 91 of the silo 90 is within reach of the person 80 supported by the free outer end 17 of the rightmost arm 13 of the system 1 suspended inside the silo 90, in this case suspended underneath the supporting location at the free outer end 17. The length 10L of the system 1 is in particular 10-20 meters. The arms 12,13 of the support structure 10 each have a length of 5-12 meters, e.g. of around 10 meters each.

One or both of the outer ends 16,17 of the arms 12,13 of the support structure 10 are provided with one or more guiding members 18 in the form of a set of wheels 18, see the detail of the outer end 16 in figure 2b. These wheels 18 are configured for engaging a surface 92, in the illustrated use in figures 3-6 a ceiling part of the inner surface 92 of the walls 91 of the enclosure 90, and guide the outer ends 16,17 along this surface 92 in a direction perpendicular to the arms 12,13. Such a direction is for example a tangential direction DTG of a rotation R of the system 1 around a vertical axis 19 through the suspension of the system 1 , as indicated in figure 5. A tangential force FR, for example exerted by the supported person 80 against the inner surface 92 of the side wall 91 of the enclosure 90, may cause such rotation Rv, in order for the supported person 80 to be displaced in that direction and continue his work on the piece of the surface area that has consequently come into his reach.

Now referring to figures 3 and 6, the system further comprises, for one or both of the arms 12,13 of the support structure 10, respective rope guides for guiding the climbing rope 61 from a fixation point 62 above the central section 2 via the inner end 15 of the respective arm 13, along the arm 13 via the outer section, namely the outer free end 17, thereof downwards from the supporting location to a fixation point of a climbing harness 81 of the person 80 being suspended underneath the supporting location. In embodiments, the system includes the climbing rope 61. In this shown use of the system 1 , fixation point of the climbing rope 61 is a point at the ceiling of the silo 90, however, it will be clear that other locations are suitable as well - for example the lifting device 70, a point at the side wall of the silo 90. In other embodiments, the climbing rope 61 may be attached to a part of the system itself, e.g. having a dedicated rope fixation point therefor, e.g. on the upright stand 20. The climbing rope 61 may not even be guided via an inner end 14,15, and possibly neither via an outer end 16,17, e.g. in case the rope fixation point is provided at the inner end 14,15, or even at the outer end 16,17.

The arms 12,13 of the support structure 10 are each pivotable around a lateral pivot axis through the central section 2, in particular through the respective inner ends 14,15, from an operational position to a collapsed position. This pivoting is indicated by the curved arrows in figure 2b. In the figures, the support structure is shown only in the operational position, wherein the arms 12,13 of the V-shaped support structure 10 each define an acute angle with the vertical direction Dv of around 80 degrees. In the collapsed position (not shown) of the support structure 10 the arms 12,13 of the support structure 10 each are substantially vertical, e.g. extending in the vertical direction Dv, e.g. such as to extend substantially along the upright stand 20 with the outer ends 16,17 directed upwardly, or such as to extend e.g. in line with the upright stand 20 with the outer ends 16,17 directed downwardly. The arms 12,13 may also be pivoted to other angles with the vertical direction Dv, e.g. to other operational positions wherein the support structure is V-shaped, e.g. with the arms having angles of 60- 85 degrees with the vertical direction Dv, and e.g. to other positions, e.g. intermediate or collapsed positions, or more extended positions. From the figures it may be envisaged that the system may in embodiments comprise one or more actuators (not shown), e.g. cylinders or electric motors, for driving the pivoting movement of the arms 12,13 around the lateral pivot axes, between the operational position and the collapsed position of the support structure 10 and/or to other positions.

In order to reach the suspended position of the person 80, the person 80 generally has to be moved onto the support structure 10, and has to walk over the arm 13 from which the person is to be suspended, to the outer end 17, where the person can secure the harness 81 to the climbing rope 61. In the shown embodiment, therefore, both of the arms 12,13 of the support structure 10 are adapted for supporting a person 80 from below on each of the arms 12,13. Embodiments are envisaged wherein the arms 12,13 further comprise a longitudinal walkway.

During the walk over the arm 13, it is possible for the person 80 to secure himself to the tensile member(s) 33,34, e.g. with a carabiner attached to the harness 81 via a fall arrest rope. The tensile members 31,32,33,34 are therefore, for safety purposes, preferably configured to facilitate fall protection of the secured person 80 that is supported on, e.g. walking over, the support structure 10. The tensile members 31,32,33,34 may in this embodiment be configured, in addition to supporting the arms of the support structure, to support the person 80 from above e.g. in case the person falls from the support structure 10 during his walk. Such support may involve a downwards deformation of the tensile member 31,32,33,34 - for example, the associated tensile member(s) may be pulled into a V-shape as a consequence of the support. In the shown embodiment, the tensile member(s) are each configured to absorb a peak load of at least six times a reference weight of 100kg. The climbing harness of the person 80 will generally reduce the peak load to six times the weight of the person 80.

The arms 12,13 of the support structure 10 are embodied as truss structures, constructed at least of longitudinal outer main chords and a plurality of diagonal members laterally and vertically interconnecting the main chords. The support structure 10 is predominantly made of aluminum. The inner and outer ends 14,15,16,17 of the arms 12,13 are made of stainless steel. As a consequence, the system has a total weight of below 300 kg. The tensile members 31 ,32,33,34 are fiber ropes, made of ultra-high molecular weight polyethylene.

As can be envisaged from the shown use of the system 1 , a method for supporting the person 80 at a horizontal distance from the suspension of the system 1, involves suspending the system 1 via the attachment member 40 from the suspension facility 70, which in turn involves engagement by the facility of the attachment member 40. The method involves supporting the person 80, as discussed in relation to figures 3-6, at the supporting location along one of the arms 12,13, e.g. at the free outer end 16,17 thereof as shown, while providing a counteractive, downwards counterforce Fw on the system at a longitudinal side of the suspension opposite to the supported person 80, e.g. on the other one of the arms 12,13.

In the method illustrated by figures 3-6, the supporting of the person 80 is performed by suspending the person 80 from the one of the arms 13 underneath the supporting location. In this case the supporting location corresponds to the free outer end 17 of the arm 13. The method may further comprise, prior to the suspending of the person 80, attaching the climbing rope 61 departing from the one of the arms 13 to the fixation point of the climbing harness 81 of the person 80. The person will generally secure the climbing harness 81 to the rope 61 after his walk over the arm 13, while being secured to one or more of the tensile members 33,34, but may alternatively already be secured to the climbing rope 61 prior to his walk.

The support structure 10 being collapsible, makes that the method may include, prior to at least the supporting of the person 80, unfold the system from the collapsed position to the operational position. In particular, the method may comprise firstly inserting the system into the enclosure 90 whilst the supporting structure 10 is in the collapsed position, wherein the unfolding is performed after the insertion. In the shown case, the system 1 is inserted whilst collapsed through the manhole in the ceiling, by lowering the hoist cable 71 from the lifting device 70.

The use of the system may comprise an action relating to a surface 92 within reach of the person 80 supported at, in this case suspended underneath, the supporting location at the free outer end 17, the action for example comprising inspecting the surface 92, cleaning the surface 92, performing maintenance on the surface 92, and/or performing construction work on the surface 92. As explained in relation to figure 5, the method may after at least the suspending, include causing a rotation Rv of the system around a vertical axis 19 through the suspension of the system 1 via the attachment portion 40, e.g. by exerting a tangentially directed push-off force F _R by the supported person 80 against a surface 92 within reach of the supported person 80, in this case of the side wall 91 of the silo 90.