Patent Grant
9556625
This application is a 371 U.S. National Stage of International Application No. PCT/IB2012/051092, filed Mar. 8, 2012, and claims priority to British Patent Application No. 1103876.7, filed Mar. 8, 2011, the disclosures of which are herein incorporated by reference in their entirety.
This invention relates to a scaffolding system. Particularly, but not exclusively, the invention relates to a suspended scaffolding system, for example of the type for use in the construction, inspection and maintenance of structures, in particular spanning structures.
Although reference has been made to spanning structures, it is understood that the invention may be used in the construction, inspection and maintenance of many other different types of structures such as: buildings, tunnels, elevated roadways, walkways, aqueducts, and other similar civil engineering undertakings.
Many different structures span across a distance of for example, ten or more meters, including bridges and viaducts. These structures require temporary access from beneath during construction, inspection and maintenance routines, however access can be difficult. One method of access is to build a temporary scaffold from the ground up but this is unfeasible in many circumstances. Another method is to build a walkway or gantry whilst the structure is being built, however this increases costs at that stage, requires foresight and also may require security to prevent unauthorised access of the gantry.
It has therefore been recognised for a long time that a temporary structure, that is cheap and easy to deploy; is adaptable to a variety of different locations and situations; and which is safe and easy to use is wanted for construction, inspection and maintenance.
U.S. Pat. No. 4,154,318 and French Patent 2845715 disclose the use of a mobile suspended scaffold which is mounted onto a vehicle. The vehicle is driven along a bridge enabling work or inspection. If there are obstacles along the edge of the bridge the whole scaffold must be retracted and repositioned making it awkward to use in some circumstances. Some existing scaffolding systems are a suspended type ones (PERI type), but they have supporting and stabilizing elements as beams, frames or portal frames mounted on the upper surface of the structure/bridge resulting in blocking or restricting of this space use for other purposes whilst the scaffolding is present.
An object of the invention is to overcome problems associated with aforementioned construction, inspection and maintenance systems by providing a single system that is suitable for a variety of different structures, which is physically able to be re-arranged to suit different applications and that is simple and cheap to use and is readily deployed and most importantly safe. No prior art arrangements achieve simple and effective stabilization of the suspended object in relation to the solid structure by the method described in this invention.
According to the present invention there is provided a suspended scaffolding system which includes a connector system adapted to engage a fixture, the fixture in use is in contact with a surface of a structure, an arm connects the suspended scaffolding system to the connector system, so that in use the suspended scaffolding system is suspended below the structure, characterised in that, the connector system has connectors that permit relative movement with respect to the fixture in two orthogonal planes.
Preferably, relative movement is permitted with respect to the fixture in three orthogonal planes.
Thus, according to this aspect of the invention, the scaffolding system is able to move laterally (from side to side). This lateral motion is achieved by way of the connector. Preferably, the connector comprises a spherical device supported within a tubular device, but other solutions, for example as Cardan mount, can be used. In a preferred embodiment, the connector includes a spherical bearing. The connector may comprise a universal connector.
Alternatively, the connector includes a ball and socket device.
It is preferred that the fixture comprises a track along which the scaffolding system can run. This enables the scaffolding system to move both laterally (from side to side) and forwards and backwards.
Rapid, safe and easy motion of the scaffolding system, lengthwise along the bridge or structure, is important as the quicker and easier it is able to transport equipment and personnel to a desired location the better this is. However, when reaching a specific position, it is important that the suspended scaffolding system is able to be placed into a relatively stable and stationary state so that crew using it can work on the structure safely and without undue movement in the suspended scaffolding system. Prior art generally requires elaborate locking and the deployment of safety equipment so that this could occur. Deployment and retrieval of the locking and safety equipment took time and so reduced productivity.
According to a second aspect of the invention there is provided a suspended scaffolding system including a connector system adapted to engage a fixture, the fixture in use is in contact with a surface of a structure, an arm connects the suspended scaffolding system to the connector system so that in use the suspended scaffolding system is suspended below the structure, characterised in that at least one moveable counterweight is provided on the suspended scaffolding system, which is adapted to be displaced from a first position to a second position so as to change the centre of gravity of the suspended scaffolding system.
The invention provides an alternate manner of providing movable scaffolding for a structure by utilising a counterweight to stabilize a suspended movable scaffolding, having adaptable geometry, easily stabilized, lockable and equally easily releasable during the process of work carried out, able to overcome obstacles structurally present in the main structure without using large areas of the upper surface of the structure for mounting support elements.
The scaffolding is suspended from a fixture which preferably comprises a rail, either on the top of the main structure, its edge or underside. If the rail and a cooperating carriage system on the scaffolding system is used as the attachment, the working platform and the scaffolding can move as work progresses along the structure.
A further object of the invention is to provide a suspended scaffolding system having a support positioned on one or more of the upper, side and/or lower surface of a structure whereby a counterweight movable between two positions moves the suspended scaffolding system's centre of gravity thereby producing a pushing force for stabilizing the equipment in a working position against main firm structure or object (building, bridge, slab, terrace or cliff, rock, cave, ship etc.).
Thus the movement of the counterweight changes the position of the centre of gravity of the system by producing an acting force that pushes the suspended scaffolding against the main stable structure and in that way stabilizes scaffolding position.
Preferably, a hydraulic jack powered by a motor is provided to displace the counterweight. Alternatively or additionally a hand crank is provided to displace the counterweight. Another system of displacing the counterweight can be introduced, electric or pneumatic jack for example, or even manually operated one such as a chain winch or pulley. The person skilled in the art will appreciate which alternative embodiments are suitable for use with the system.
According to a third aspect of the invention there is provided a suspended scaffolding system which includes a track connector system adapted to engage a track, the track in use is in contact with the surface of a structure, characterised in that the track connector system comprises at least three fasteners each of which is in contact with the track and each is adapted to be temporarily removed from the track, when encountering an obstacle, so as to permit the suspended scaffolding system to negotiate the obstacle or to move into a new position.
According to a fourth aspect is a method of moving a scaffolding system which is movable along a rail, the rail being fixed to a surface by at least one fastener comprising the steps of:
The fastener can be removed from the rail entirely or pivoted out of the way. This arrangement enables the scaffolding system to be used along the entire length of a structure, straight or curved, which is for example a bridge, on a rail, runner or section of a rail or runner. Sections of rail or runner may be removed and placed ahead of another section.
In a preferred embodiment, the suspended scaffolding system includes a suspended working platform (SWP™) and a safety rails disposed around a periphery of the working platform.
Traditionally, in this type of system, reaction bearings or end stops are used to prevent the scaffolding system overrunning and either becoming completely dislodged from the rail or causing damage to the connector of the scaffolding system. However, the fact that end stops are used means that these have to be removed when a new rail section is added which is time consuming and requires extra parts.
In the present invention, it is preferred that a rail end automated blocking device, designed within the rail itself, is used which are active if the rail segment is the end one, but which is de-activated by the connection on the next rail segment. This has the added safety advantage that a worker does not have to remember to add an end piece during construction; each rail has an end piece integral to it.
According to another aspect of the invention, there is provided a method of stabilizing a suspended structure comprising the steps of: providing a suspended structure; and adjusting the suspended structures' centre of gravity away from a neutral position thereby producing a stabilizing force.
Preferably, the adjustment of the suspended structures' centre of gravity is achieved by one or more of counterweight movement, ballasting and swinging. Example include moving a mass element (sliding, swinging, rotating, pumping ballast from tank to tank) or by adding or removing mass to/from the object (filling/emptying ballasting tanks).
In a preferred embodiment, the stabilizing force is transferred to a supporting structure using a bumper.
Preferably, there is provided one fixed suspension point located on the upper, side or lower edge/surface of the structure and at least two bumpers of the suspended object in contact with the structure, giving in total three points of stabilization of the suspended object position.
In a preferred embodiment, there are provided two fixed suspension points located on the upper, side or lower edge/surface of the structure and at least one bumper of the suspended object in contact with the structure, giving in total at least three points of stabilization of the suspended object position.
Adjusting the centre of gravity by deployment of for example a counterweight, the centre of gravity of the scaffolding system is shifted from a first location, at which the scaffolding system hangs freely on one or more fixing points and is able to move freely, for example by running along a rail, to a second location in which the scaffolding system is urged against the structure so that the scaffolding system is held in a relatively fixed position with at least two points in contact with a rail or runner and at least one, the third point in contact with the structure, which as a result of a reaction force ensure that the scaffolding system remains stationary, but which can be moved to a different location relatively quickly and easily, even by personnel who are on board a working platform supported by the scaffolding.
Preferably the third point of contact is by way of a friction pad or buffer/bumper.
Preferably, the suspended scaffolding system comprises a contact point, with the structure, includes a reaction bearing roller.
Therefore, it is an object of the invention to provide the technical stabilization method of the suspending objects/technical equipment in relation to the main stable outer structure by using the adjustable and lockable counterweight as part of the suspended object and by this counterweight intentional displacement inducting pushing/locking force stabilizing the suspended object to the main structure.
When using movable and adjustable counterweight and bumper/buffer system the SSS—Suspended Scaffolding System do not requires any additional top surface level or under surface level cooperation or support except own one. When the movable and adjustable counterweight is engaged it pushes the SWP—Suspended Working Platform towards the bridge/structure locking it into position. When the counterweight is disengaged, there is no pushing and no contact with the bridge/structure and the SWP can be easily moved/passed, to the new working area.
The SSS—Suspended Scaffolding System is more practical and cost-effective solution, than the currently used ones: top support mounted frames with suspended arms; trailer under bridge inspection units; lower level surface mounted up scaffolding for the structure above. The invention is presented here (as particular example, not excluding other different applications) as the mode to construct the suspended scaffolding with working platform (SWP) for carrying the maintenance or structural work from underneath the bridge/structure without using the constructing extended scaffolding structures on the top of the bridge as support for the mounted down scaffolding towers with suspended on the underside working platforms. The SSS solution saves time and money, as well leaving upper bridge/structure surface freely accessible for other stages of construction work or the standard uninterrupted and not distracted use.
The invention will now be described, by way of example, with reference to the accompanying drawings: in which:
Each of
For applications in which the suspended object is movable along the length of the structure, a rail 31 is provided for attachment to the structure 30 and one, two or more independent carriage/truck sets 32 are provided which roll within the rail 31 connected via a pin mounted in a bearing 33 at the end of the suspended object/suspended working platform beam or arm 34,39.
The fixing system includes a spherical bearing 33 or Cardan mount or any other bearing solution allowing rotation in any plane. The suspended object/suspended working platform frame is represented here by the suspended object/suspended working platform beam or arm 39 (
The whole suspended object/suspended working platform 34,35,36,37,39 in a free hanging position (
In examples where the support points 31 are provided on a rail, in this configuration—hanging freely—the suspended object is easily movable along the length of the structure and can pass obstacles.
The suspended working platform 34,35,36,37,39 comprises suspended object/suspended working platform beam or arm 39 through which the suspended object is attached to the structure 30, vertical side frames 34, a horizontal frame of working platform 35 and bumpers/buffers 36 for abutment to the underside 29 of the structure 30. The angle and length of the bumpers and buffers 36 are adjustable according to need. In the free hanging position (
The stabilization effect of the free hanging object to the main outer structure is achieved by adding a counterweight 37, to the suspended object/scaffolding, and adjusting this counterweight's position. The counterweight can be moved and locked in different positions in relation to the suspended object/scaffolding, for example by the use of rails and hydraulic jack).
When the centre of gravity 38 of the whole hanging structure (suspended working platform 34,35,36,39 and counterweight 37 and possibly workers, equipment and materials as well as add-on accessories) is in a neutral position, it lies within a strictly vertical plane B below the upper attachment point/points 31, then the whole structure is hanging freely—like the scheme pictured on
When the counterweight part 37 of the whole suspended working platform 34,35,36,39 is intentionally repositioned in direction C opposite the main outer structure location 30 i.e. away from the centre of the structure 30 or towards an outer edge of the structure 30, then the centre of gravity 38 of the whole structure (suspended working platform 34,35,36,39 and counterweight 37 and possible workers, equipment and materials as well as add-on accessories) is moved off its neutral position—like the schemes pictured in
In this position, the main acting force—the gravity, is forcing the shifted centre of gravity 38 back towards neutral position which is exactly within a strictly vertical plane below the upper attachment point/points 31. However, this movement is prevented by the bumpers/buffers, that indicated force F3 52 is then transferred into the structure 30 via bumpers/buffers 36, and the passive resistance of the structure 30 gives the stability to the whole equipment. The suspended object/suspended working platform remains then in the stabilized, locked-in, working position, as pictured in
Note: the forces diagrams of
In the free hanging position of the suspended object (
The rail 120 is secured to a structure 30, such as a bridge, using spaced apart distance supporting pads 126 (see
The suspended working platform—SWP 100 includes frame having a base portion 111 and two side portions 110 which are disposed on opposite sides 110′,110″ of the base portion 111. At the distal end of each of the side portions 110 a pivotable arm 114 is provided. The frame base 111 is, in use, partially suspended beneath a structure 30 via the frame sides 110 and the pivotable arms 114.
The base 111 includes a counterweight system 140 which comprises a counterweight 142 which is moveable between working positions as shown and a non-working or passable position (see
The pivotable arm 114 includes an aperture 218 in which a spherical bearing 118 is housed. The carriage/truck 112 has two vertically disposed extensions 212 in between which the pivotable arm 114 is located. The extensions 212 each have an aperture (not shown) which align with each other and the aperture 218 of the pivotable arm 114 enabling a pin 214 or other fastener to secure the pivotable arm 114 to the carriage/truck 112 via the spherical bearing 118. When the carriage/truck 112 is moved along the rail, the pivotable arm 114 and thus the frame 110, 111 is moved along the rail.
The counterweight 142 is attached to counterweight carriage 148. The counterweight carriage 148 has wheels 248 which are adapted to run along the counterweight rail 144. A counterweight stabilizer 150 is introduced to stabilize counterweight from swinging. A counterweight shield 146 covers the counterweight rail 144 and the wheels 248 of the counterweight carriage 148 protecting them from damage and ingress of dirt etc. . . .
A hydraulic jack 152 is connected to either the counterweight 142, via mounted plate 154, or to the counterweight stabilizer 150 and when actuated, the jack 152 moves the counterweight 142 linearly along the path of the counterweight rails 144. Movement of the counterweight 142 is generally perpendicular to the longitudinal axis A-A of the structure 30 and this movement causes pivoting of the frame 110, 111 with respect to the structure 30 about rotational axis B-B between a free hanging and a working position when the frame 110,111 is stabilized to the structure 30.
An upper platform 374 provides access from the structure 30 to a first ladder 378. In this example, an intermediate platform 376 is provided at the bottom of the first ladder 378 with access to a second ladder 380 which leads to the working platform 372. A skilled person will understand how many, if any, intermediate platforms are required.
The scaffold 370 is an infill, of suspended scaffolding system and its suspended working platform and can be any required system scaffolding for example PERI, but any appropriate scaffolding system can be used. The scaffold infill 370 creates a wall 382 around the perimeter of the frame base 111 and a tower 384 around the access point and ladders 378,380. At the corners 388 of the frame base 111 distal to the frame sides 110 i.e. the corners of the frame base 111 which are underneath the structure 30, the corner upright 392 of the scaffold wall 382 extends beyond the wall height ending in an abutment bumper or buffer 390. When the counterweight 142 is in its' working position, as shown, the abutment bumper 390 abuts the underside of the structure 30. The abutment bumper is an integrated part of this invented device, not the standard scaffolding infill.
The frame sides 110 are each connected to a carriage/truck 112 which can be moved along rail 120 which is connected to a structure 30 using spaced apart distance supporting pads 126 between the rail 120 and the structure 30 and rail fasteners 122 which bridge over the rail 120.
The rail fasteners 122 are spaced apart by a nominal distance of around 200 cm however this can be smaller or larger depending on the structure 30. The rail fasteners 122 fix the rail 120 and in addition act as a stop/obstruction for the scaffolding system 350 movements. In order to move the scaffolding system 350 further along the structure, a rail fastener 122 must be temporarily doubled (one in front of, the other behind the carriage to be moved) to allow one fastener to be removed or pivoted away from the rail 120. It is preferred that the distance and multiples of the distance between rail fasteners 122 is not the same as the distance between the two frame sides 111 so only one fastener 122 is removed or displaced at a time to allow passage of the scaffolding.
In this example, in order to move the scaffolding system 350 further along the structure, a rail support 122 must be removed or pivoted away from the rail 120. Again, it is preferred that the distance and multiples of the distance between rail fasteners 122 is not the same as the distance between the two frame sides 111 so only one fastener 122 is removed or displaced at a time to allow passage of the scaffolding.
Some or all of the scaffolding system 350 may be removed from a structure 30 when not in use as the scaffolding 370 is easy to dismantle and transport, the frame sides 110 could be unbolted from the frame base 111 and the rail 120 removed. Alternatively, the scaffolding system 350 is left attached to a structure 30.
The hydraulic jack may be supplemented by a hand crank in case of failure or replaced by a hand crank or alternative movement options.
In the examples shown and described herein, the rail or track 120 is shown as being located on the upper surface of the structure 30 (see
One use of the suspended working platform 100 is to provide under bridge access for carrying the construction, maintenance or inspection work to the lower and side surface of the structure 30. The suspended working platform 100 is delivered on the required work site in parts (dismantled or folded), then the main frame (side frames 110 and horizontal working platform 111) and other structural parts of SWP are assembled together and attached to the supporting fixing points or rail 120 (by crane for example from below, or from above; by chopper; by sea ship crane). Then the whole optional add-on accessory (372,374,376,378,380,382,384,390
SWP frame 100 has adjustable geometry and structure according to particular case and purposed use and is erected to the geometrical form of the structure 30. The dimensions and geometry of the SSS—Suspended Scaffolding System equipment varies in each particular case of use, adjusted to specific needs, the geometry of the structure to be work subject and the specific requirements of the work type to be carried out, for example:
It is to be appreciated that these Figures are for illustration purposes only and other configurations are possible.
The invention has been described by way of several embodiments, with modifications and alternatives, but having read and understood this description further embodiments and modifications will be apparent to those skilled in the art. All such embodiments and modifications are intended to fall within the scope of the present invention as defined in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1103876.7 | Mar 2011 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2012/051092 | 3/8/2012 | WO | 00 | 9/6/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/120471 | 9/13/2012 | WO | A |
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