Scaffold with scaffolding elements and methods for erection thereof

Abstract

A scaffold comprising at least two horizontally adjacent scaffold sections, the scaffold sections being defined substantially by lengthwise ledgers, transverse ledgers and uprights, characterized in that the scaffold comprises a guide adapted to be able to displace in substantially horizontal direction therealong a displaceable platform corresponding thereto and guided thereby; a method for erecting the scaffold, and a mobile platform.

Claims

1. A scaffold comprising: a plurality of lengthwise ledgers; a plurality of transverse ledgers interconnecting the lengthwise ledgers; and a plurality of uprights supporting the plurality of lengthwise and transverse ledgers, wherein the scaffold has multiple scaffold sections having adjacent scaffold sections, each of the multiple scaffold sections comprising a plurality of pairs of horizontally parallel lengthwise ledgers of said plurality of lengthwise ledgers, wherein each lengthwise ledger of said plurality of lengthwise ledgers comprises a respective upper rod configured to allow a displaceable platform to be supported by at least one pair of the said plurality of pairs of horizontally parallel lengthwise ledgers of said plurality of lengthwise ledgers during a movement of said displaceable platform along the respective upper rods of the plurality of lengthwise ledgers, wherein the said plurality of lengthwise ledgers are coupled to the uprights via a plurality of intermediate support elements, wherein each of the plurality of pairs of horizontally parallel lengthwise ledgers are coupled to a respective inner side of each upright of said plurality of uprights via the plurality of intermediate support elements, wherein the lengthwise ledgers of adjacent scaffold sections of said multiple scaffold sections are interconnected via the intermediate support elements so that a plurality of pairs of horizontally parallel continuous rails are formed from the respective upper rods of each of the said plurality of lengthwise ledgers and are coupled to the respective inner side of the uprights throughout the adjacent scaffold sections of said multiple scaffold sections configured to allow the displaceable platform to roll along the rails without being obstructed by the uprights, and wherein each lengthwise ledger of said plurality of lengthwise ledgers comprises: a double ledger structure comprising the upper rod of each lengthwise ledger of said plurality of lengthwise ledgers coupled to a lower rod that is disposed in parallel directly beneath the upper rod of each lengthwise ledger of said plurality of lengthwise ledgers via a plurality of vertical support structures disposed there-between, and a plate disposed at each of a pair of outer ends of both the upper rod and lower rod of each lengthwise ledger of said plurality of lengthwise ledgers.

2. The scaffold according to claim 1, wherein the transverse ledgers are coupled to the lengthwise ledgers via the intermediate support elements which are disposed below the said plurality of pairs of lengthwise ledgers forming the said plurality of pairs of continuous rails, wherein the scaffold is configured to allow movement of the displaceable platform without obstruction by the transverse ledgers.

3. The scaffold according to claim 1, wherein the lengthwise ledgers are coupled to the intermediate support elements at respective sides facing a longitudinal direction, and wherein each of the intermediate support elements comprises an upper surface that is coupled to the plurality of pairs of continuous rails formed by the lengthwise ledgers throughout the adjacent scaffold sections of said multiple scaffold section.

4. The scaffold according to claim 3, wherein a length of the upper surface of the intermediate support elements is substantially greater than a width of the uprights.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings are used to illustrate embodiments of the present invention.

(2) FIG. 1A is a perspective view of a scaffold concept according to embodiments of the present invention.

(3) FIG. 1B is a top view of such a scaffold which shows a diagonal present in a horizontal plane in one of the sections.

(4) FIGS. 2A to 2I show details of FIG. 1A.

(5) FIGS. 3A to 3D show front, top, rear and side views of a support block according to embodiments of the present invention.

(6) FIGS. 4A to 4D show respectively a front view, a rear view, a cross-sectional view along the line A-A in FIG. 4A and a side view of a half support block according to embodiments of the present invention.

(7) FIG. 5A shows a side view of a lengthwise ledger according to embodiments of the present invention. FIG. 5B is a front view of the coupling means of the ledger which comprises two slots.

(8) FIGS. 6A to 6F illustrate embodiments of a connecting ledger according to embodiments of the present invention.

(9) FIG. 6A shows a perspective view, FIG. 6B a cross-sectional view along line C-C in FIG. 6C. FIG. 6C is a side view. FIGS. 6D and E are end views of the ledger. FIG. 6F is a top view.

(10) FIGS. 7 and 8A to 8C illustrate two types of pairs of slots in the coupling means of the ledgers according to embodiments of the present invention.

(11) FIGS. 9A and 9B show a front view and a cross-sectional view in the direction A-A indicated in the front view of a coupling plate of a support block, or extension ledger. The coupling means of a half support block is similar.

(12) FIG. 10 shows a top view of a non-standard construction of a scaffold in which a determined scaffold column has a greater width than the standard scaffold sections.

(13) FIGS. 11A, 11D and 11E show respectively a front view, a top view and a perspective view of an extension ledger according to embodiments of the present invention. FIGS. 11B and 11C show front views of coupling means suitable for coupling to the coupling means of the extension ledger.

DESCRIPTION OF THE ILLUSTRATIVE EXAMPLES

(14) The above stated and other advantageous features and objects of the invention will become more apparent and the invention better understood from the following detailed description when read in combination with the respective drawings.

(15) The description of the aspects of the present invention is given by means of specific embodiments and with reference to, but not limited to, specific drawings. The figures shown are only schematic and should be deemed as non-limitative. Determined elements or features may for instance be shown out of proportion or scale in relation to other elements.

(16) FIG. 1A shows a scaffold according to preferred embodiments of the present invention. The scaffold comprises rows and columns (I, II, III) of scaffold sections. Each of these scaffold sections is defined substantially by corresponding uprights 6, lengthwise ledgers 4L and transverse ledgers 4B. The scaffold sections can further be strengthened by the use of diagonals 8. At the bottom the uprights typically comprise a foot jack 7.

(17) According to preferred embodiments of the present invention, ledgers 4L, 4B are connected to support means or support ledger 50 and support blocks 51, and 52. An extension ledger 4VL can also be arranged between for instance a support block 52 and a main ledger 4L. These support blocks 51, 52 and support ledger 50 are in turn connected to uprights 6. Support blocks 51, 52 and support ledger 50 are further also adapted for coupling to ledgers 4B which mutually connect two adjacent uprights in the width direction. The use of support blocks 51, 52 and support ledgers 50 allows arrangement of the ledgers within the section defined by their respective uprights; in other words, the ledgers can be positioned on the interior of the scaffold defined by the uprights, i.e. on the side of the uprights pointing inward into the scaffold. These ledgers are preferably also adapted to serve as guide means for a platform guided displaceably thereby. The displaceable platform, typically comprising a wheel device 31, a work-floor 33 and a rail 32, can be displaced over this guide surface of the lengthwise ledgers. This by allowing co-action of the wheels of wheel device 31 with the rails formed by, among other parts, the lengthwise ledgers and parts of the support blocks. The support blocks can themselves be provided for this purpose with a rail part or ledger part which, together with a guide surface of ledgers 4L, form a continuous rail through the scaffold construction at a determined ledger level. This is possible for instance at each ledger level. A mobile platform can take the place of the work-floors for a specific scaffold level. Different types of support blocks are described here; the narrow support blocks 52, the half support blocks 51 and support ledgers 50. These elements will be described in more detail below. The displaceable platform is preferably a lift cage or a climbing lift as described respectively in the Belgian patent applications 2010/0442 and 2010/0443. Described in BE2010/0442 of these applications is a so-called climbing lift which allows ascent and descent in a scaffold. During ascent or descent in the scaffold this climbing lift can transport construction material for the scaffold. In BE2010/0443 a lift cage is described as an alternative platform allowing movement up and downward in vertical direction in a scaffold column. These respective climbing lift or lift cage devices are then preferably provided with guide means 31 which can co-act with the rails formed by lengthwise ledgers 4L and the respective support blocks 51, 52 or support ledgers 50. The horizontally displaceable platform 3 is preferably also a vertically displaceable platform, or it can be displaced on a vertically displaceable platform (and carried into the scaffold from the vertically displaceable platform).

(18) In embodiments according to aspects of the present invention it is possible to erect a scaffold in an alternative, rapid and efficient manner using an above stated climbing lift or alternative device which allows vertical transport of material in a scaffold column. In order to illustrate the idea we shall assume that scaffold column II is a column in which displaceable platform 3 can be displaced vertically.

(19) During erection of prior art scaffolds the lengthwise ledgers typically extend from upright to upright, or they extend at least from their first outer end located close to the first upright (for instance the rosette of a Layher upright) to a similar position on an adjacent upright. The lengthwise ledgers are difficult to stack horizontally here without leaving essential space clear for the personnel erecting the scaffold. Stacking of the scaffold material at an angle or vertically is less obvious. By using support blocks in the form of support ledgers 50 or half support blocks 51 the overall distance between two adjacent uprights in the longitudinal direction can be made substantially greater than the standard length of a lengthwise ledger 4L. When such ledgers are stacked horizontally on the climbing lift or an alternative work-floor which can travel on the rails, a person can be placed on both sides of the horizontally stacked ledgers 4L. Together they can easily lift ledger 4L upward and couple it to the support blocks.

(20) Because the displaceable platform 3 can displace along the rails at a determined level in substantially horizontal direction, a complete row of scaffold sections can be erected quickly and efficiently by travelling with a displaceable platform 3 on the upper ledgers of the underlying row of scaffold sections. Once a subsequent level of scaffold sections has been erected in such manner, the displaceable platform 3 can preferably be re-placed in scaffold column II. The displaceable platform 3, can then ascend a level further in the scaffold and the following row of scaffold sections can be erected in similar manner. Once the scaffold material has been used up, the displaceable platform 3 can descend via the optionally wider scaffold column II to ground level to load material for further construction. The skilled person will appreciate that the scaffold system according to aspects of the present invention is indeed a very rapid, efficient and so less cost-intensive solution for erecting scaffolding constructions.

(21) Once the whole scaffold has been erected in such an efficient manner, the displaceable platform can for instance be converted to a lift cage system or lift system or, after removal of the climbing lift, such a lift system can be arranged in a determined scaffold column. The lift system preferably comprises a guide means for guiding a horizontally displaceable platform. Such a guide can for instance be realized by using rail elements of the type used for the ledgers and support blocks and arranged on a floor part of the lift system. Mobile platforms can then be arranged at one or more levels of the scaffold in order to perform determined operations on for instance a building. It is therefore no longer necessary to have to arrange work-floors in the scaffold, this resulting in quite some time-saving. These mobile platforms can be arranged permanently at specific or all levels of the scaffold during work operations. It is also possible for one or more displaceable platforms to change level in the scaffold during work operations by making use of the lift system. In determined embodiments a lift system is used in a standard scaffold construction and the horizontally displaceable platforms are adapted to retract/extend the wheels in the transverse direction. In alternative embodiments at least one wider scaffold column can be erected in which the lift system will later be arranged. The width of the platform 3 can then be relatively greater, and this allows the use of horizontally displaceable platforms having a constant wheelbase and so being of simpler construction (see FIG. 10).

(22) In an alternative construction scenario, wherein the guide system is arranged only at a determined, e.g. the lowest, level of a scaffold, typically for use with scaffold material not per se comprising a guide system, e.g. Layher systems, a complete scaffold column can be erected to a predetermined height by making use of for instance a climbing lift. The climbing lift can then descend back to ground level and travel on the rails arranged in the lowest level of the scaffold to for instance the adjacent scaffold column. This can then be erected vertically in similar manner, and so on. Existing scaffolding systems can also be improved in such manner, for instance in the sense that the erection/dismantling thereof can be accelerated.

(23) The skilled person will appreciate that embodiments of the present invention allow not only the above stated but in fact a whole range of new erection scenarios for scaffolds.

(24) The use of a half support block 51 is typically advantageous close to an outer end of the scaffolding construction (for instance on the left or right) where no further erection is required. Support blocks 50, 51, 52 can in any case be coupled to further ledgers or extension ledgers. This can take place by means of different mechanisms, several of which are described below. The connection between width ledgers 4B and the associated support blocks 50, 51, 52 can also take place by means of the same coupling mechanisms.

(25) FIG. 1B shows a top view of the scaffold of FIG. 1A. The section furthest to the right here comprises a diagonal according to embodiments of the present invention.

(26) FIGS. 2A to 2G show details of FIG. 1. FIG. 2A shows a perspective view of a half support block 51 coupled to an upright 6 in the longitudinal direction of the scaffold and to a width ledger 4B in the width direction. FIG. 2B is similar but illustrates the use of a full support ledger 50. FIG. 2C shows the coupling between a lengthwise ledger 4L and an extension ledger 4VL in more detail. FIG. 2D shows the other side of extension ledger 4VL coupled to a support block 52. Support block 52 is connected to upright 6 and is coupled to a width ledger 4B. On the other side of the support block in the longitudinal direction there is a coupling to a lengthwise ledger 4L. This latter type of coupling is also shown in FIG. 2E, be it on the other side of the above-mentioned lengthwise ledger 4L.

(27) The specific features of the different coupling means used are described in more detail below. FIG. 2E further illustrates a diagonal 8 as example of a stabilizing element. Diagonal 8 comprises at least two, and here four arms 81 (e.g. rods) which can be oriented relative to each other and which are each connected at a first outer end 811 to a shared folding means 82 and at another outer end comprise a connecting means (812, 813, 814, 815, 816, 817) which is adapted for fixing to elements of the scaffold. For this purpose the first outer end of arms 81 can for instance end in a ring structure which is connected as a chain link to a central ring 82. At the second outer ends of the orientable arms a similar ring structure 812 can for instance be coupled to a hole 815 in a coupling plate in a first part 814 of the connecting means. The connecting means can for instance also comprise a second part 816 lying for instance, though not necessarily, at an angle to first part 814 differing from 180 degrees. This angle is for instance predetermined as a function of the size of respective typical scaffold dimensions and as a function of where exactly the coupling between the coupling plate and the scaffold, for instance upright, support block or support ledger, has to take place. The angle can be determined such that the first part 814 comes to lie in line with the corresponding rod 81 when the diagonal is placed in a corresponding scaffold section. The second part typically comprises a hook-like recess 817 which allows hooking behind a threaded rod, for instance of a bolt. After such a hooking the second part 816 can be tightened against the upright by means of a nut, or the bolt, and the diagonal can be locally secured. The use of a hook-like recess allows a simple coupling to the threaded rod. This is illustrated in FIGS. 2F, 2G, 2H and 2I.

(28) In preferred embodiments the plane in which the ring structure extends at the first outer end 811 (the plane defined by this ring structure) can for each arm 81 lie perpendicularly of the plane in which the second ring structure 812 extends. Central ring 82 and ring structures 812 can in this way come to lie in a plane parallel to the plane defined by the rectangle spanned by the diagonal in the scaffold.

(29) The two or four arms 81 can be folded together because of the central ring structure 82, the orienting means. The length of the diagonal can hereby be reduced, this enabling horizontal stacking of the diagonal on a work platform, horizontally and/or vertically displaceable platform.

(30) A diagonal embodied with four arms 81 as described further provides an additional stability factor when compared to the situation in which two independent diagonals were to intersect or be arranged in the vicinity of each other, since a redistribution of the forces can occur at the orienting means, e.g. the central ring 82.

(31) FIGS. 3A to 3D show support ledgers 50 in more detail. FIG. 3A shows a front view, FIG. 3B a top view, FIG. 3C a rear view and FIG. 3D a side view of this support ledger. In preferred embodiments the upper surface 501 of the support ledger forms a guide surface for a displaceable platform. This is not however essential. The support ledger 50 according to this embodiment comprises a central support 502 which is provided with two recesses 5021 and 5022 on its rear side. The central support can for instance comprise a piece of hollow, square or rectangular tubing provided with the necessary openings and coupling means. Central support 502 can then be coupled using two bolts which are attached through upright 6 by coupling to respective nuts on the rear of the upright. The heads of the relevant bolts can slide here in central support 502 behind a rear surface 5023 of central support 502. By tightening the nuts on the rear of the upright the central support 502 or the support ledger 50 can thus be fixed to upright 6. The central support is further provided with a coupling means adapted for coupling to transverse ledgers 4B which will be described in further detail. This coupling means preferably comprises two threaded rod elements 5024A and 5024B which can be provided with nuts 5025A and 5025B. After coupling of threaded rods 5024A and 5024B to slots in the coupling means of transverse ledgers 4B, as will be described below, and tightening nuts 5025A and 5025B, transverse ledger 4B can be fixed to central support 502. Central support 502 is further connected to at least one elongate ledger part 50A which in determined embodiments can form a part of a rail, a guide means for a displaceable platform. This rail part 50A extends on both sides of central support 502. This can for instance be at a distance on either side of for instance 30, 40, 50, 60 or more centimeters. Provided at the outer end of ledger part 50A are coupling means for coupling to travel rail ledgers, as will be described below (in particular travel rail ledgers comprising two slots). The coupling means at both outer ends of rail part 50A here comprise a plate element provided with two threaded rod elements, a first threaded rod element 5026A situated above a second threaded rod element 5026B, to which travel rail ledgers can be coupled in similar manner as described for the coupling between threaded rod elements 5024A and 5024B. The support ledger can further also comprise a lower ledger part 50B which likewise extends on either side of central support 502 and is possibly also further connected to rail part 50A by means of additional connecting elements 503. Lower rail part 50B is also connected to central support 502 and to the coupling means at the outer ends of the support ledger, for instance using the coupling plates comprising the threaded rod elements. A strengthened support ledger or, as will be described below, a corresponding strengthened travel rail ledger is formed in this manner. Threaded rod elements 5026A and 5026B and the corresponding nuts 5027A and 5027B lie in predetermined fixed positions. This allows coupling to the coupling means at the end of travel rail ledgers which will be described below.

(32) In preferred embodiments rail part 50A comprises a rod of square cross-section which is tilted. When the support ledger is installed in the scaffold, the rod can be connected here to the rest of the support ledger by means of one longitudinal rib, wherein this longitudinal rib and the diametrically opposite longitudinal rib lie in the same vertical plane. The two other, also diametrically opposite longitudinal ribs are then typically situated in a substantially horizontal plane. The use of such a ledger part 50A (which in determined embodiments is typically a rail part) allows a connection between ledger part 50A and the rest of the support ledger 50 to be realized in simple manner (e.g. is easily welded) and also allows a locking mechanism to be realized in simple manner between wheel device 31 of a displaceable platform 3 and ledger part 50A. Note that the chosen pitch of the relevant threaded rods 5024A, 5024B, 5026A, 5026B and of their corresponding nuts 5025A, 5025B, 5027A, 5027B is relatively large in preferred embodiments so that a small rotation of the respective nuts can provide for a fixation of the support ledger to the travel rail ledger, as will be further described.

(33) FIGS. 4A-4D show so-called half support blocks 51. These half support blocks are wholly similar to the support ledgers 50 illustrated in FIG. 3, although parts 51A and 51B extend here along only one side of central support part 572. In the direction opposite to the direction in which ledger parts 51A and 51B extend the central support block part 572 comprises threaded rod elements 5126A and 5126B and corresponding nuts 5127A and 5127B. Central support 572 can hereby be coupled to for instance travel rail ledgers which are described below.

(34) Described in FIGS. 5A-5C is a ledger (e.g. travel rail ledger) for use in a scaffold according to preferred embodiments of the present invention. Ledger 4L comprises a coupling means 4L4 at each of its outer ends. The coupling means preferably comprises guide slots 4LS1 and 4LS2 adapted to be able, during placing of the ledger, to successively receive respectively a first threaded rod element and a second threaded rod element situated at fixed positions. These threaded rod elements are preferably arranged at an outer end of the support blocks 51, 52 or support ledgers 50 as described above in the longitudinal direction of the scaffold. The travel rail ledger preferably comprises a first rod 4LA which substantially defines the length of the ledger and which is coupled to coupling means 4L4 at its outer ends. In preferred embodiments this rod can serve as guide means for a displaceable platform (formed for instance by two parallel rods, two parallel ledgers). The rod can for instance comprise a square cross-section. The first rod 4LA of square cross-section can be oriented such that it lies with two diametrically opposite longitudinal ribs in a substantially vertical plane, as also described in respect of the support ledger 50. The two other diametrically opposite longitudinal ribs then lie in a substantially horizontal plane. The use of a guide surface formed hereby in combination with wheels on a displaceable platform which form a complementary guide surface provides for an increased stability of the displaceable platform on the formed rails. The complementary guide surfaces of the wheels of a displaceable platform can for instance comprise a substantially complementary radial recess (V-groove).

(35) In preferred embodiments the travel rail ledger also comprises a second connecting element, such as a connecting rod 4LB, which is also connected at its outer end to coupling means 4L4 and which is also connected in between to the first connecting element, the first rod 4LA, by means of support structures 4L3. Use of this double ledger structure increases the load-bearing capacity of the ledger, which can be highly relevant particularly in the case a relatively great load has to be carried by the travel rail ledger. This is particularly the case when use is made of a mobile climbing lift or a mobile platform, which will typically have to carry and transport a substantial quantity of scaffolding, construction and other material as well as personnel.

(36) In order to enable coupling to the threaded rod elements of the support blocks and/or support ledgers as described above, the travel rail ledger (more generally the lengthwise ledger) and the width ledger comprise a modified structure on their head. This structure comprises a substantially flat plate 4L4S which in determined embodiments can form part of a bracket structure substantially comprising two slots 4LS1 and 4LS2. Guide slots 4LS1 and 4LS2 are for instance provided in a coupling plate which is substantially flat and the main surface of which lies perpendicularly of the longitudinal direction of the ledger. The fixed position of the first and second threaded rods on the support blocks or support block ledgers is preferably such that they run parallel to the longitudinal direction of the ledgers when the guide slots receive the threaded rod elements and a coupling is thus formed between the ledger and the support block or support ledger. The slots can preferably comprise a lower slot 4LS1 and an upper slot 4LS2, wherein the upper slot lies at a higher position than the lower one. Lower slot 4LS1 is substantially straight and extends substantially vertically upward through a predetermined distance from the lower edge of the coupling plate. When a travel rail ledger or a width ledger is coupled to the threaded rod elements of the support blocks or support ledgers as described above, this can preferably take place by having the lower slot 4LS1 coupled to the lower threaded rod on the respective support blocks or support ledgers. Once the ledger, typically identical at both outer ends, is coupled to the respective first threaded rods, this ledger can temporarily support thereon. A coupling to the second slot 4LS2 can then be obtained in different ways depending on the type of slot for 4LS2.

(37) According to a first embodiment for upper slots of the first type, upper slot 4LS2 extends from a lateral edge of the coupling plate and the upper slot comprises an entry opening at a height adapted to correspond to the predetermined position of the second bolt relative to the first bolt. The upper slot preferably extends further upward in a curve. The slot comprises a lower edge 4LS22 and an upper edge 2LS21 which come together at a highest point at the end of slot 4LS2. The positions of the outer ends of the lower and upper slot are preferably adapted such that they can simultaneously receive the respective first and second threaded rods close to their respective outer ends. The upper edge (or upper guide surface) of slot 4LS2 of the upper slot further comprises locally a downward directed dip 4LS23. This dip 4LS23 blocks the passage of the second threaded rod in second slot 4LS2 in the first instance after the second threaded rod has been received to limited extent by the second slot as a result of rotation of the ledger around the first bolt. The temporary blocking of the second threaded rod by this dip 4LS23 can be released by slightly lifting the ledger. This is preferably done through a distance smaller than the length of the lower slot, so that the coupling between the lower slot and the first threaded rod is not released. Slight lifting of the ledger in combination with a further rotation of the ledger around the first bolt then provides the final coupling between the two slots and the respective threaded rods. The positions of the threaded rods preferably correspond here with the outer ends of the slots 4LS1 and 4LS2. Surfaces 4LS11, 4LS24, which define the edge at the end of the respective slots 4LS1 and 4LS2, can particularly rest here on the respective threaded rods. The connection between the connecting elements (e.g. connecting rods) 4LA and 4LB and the coupling plates of coupling means 4L4 consequently takes place at locations differing from the locations of slots 4LS1, 4LS2 so as not to obstruct the coupling to the threaded rod elements by means of the slots. Upper rod 4LA can thus be fixed to the coupling plate above the second slot and lower rod 4LB can be fixed between the first slot and the second slot. The second rod can consequently be curved upward close to its outer ends, while away from its outer ends it is situated a constant distance from the first rod.

(38) In preferred embodiments of the present invention a coupling means of the bracket type is used as coupling means for the width ledgers (also referred to as transverse ledgers or connecting ledgers) 4B. Such a structure allows tightening of respective nuts from inside the bracket in order to realize the coupling to respective support blocks or support ledgers. Such a ledger can comprise the same coupling structures with slots as described for the travel rail ledger or lengthwise ledger. FIG. 6A shows a perspective view, FIG. 6B shows a cross-section along the line C-C of FIG. 6C. FIG. 6C shows a side view of the connecting ledger. FIGS. 6D and 6E show side views of the coupling means and FIG. 6F shows a top view of the connecting ledger. The width ledgers can also be embodied without bracket structure, for instance with only a flat coupling plate as described for the lengthwise ledgers.

(39) It can further be noted that the space created by the upper rods or connecting elements 4LA of square cross-section is not required for the width ledgers, since these are not typically used as guide means for a displaceable platform 3. Connecting elements 4BA can thus have a circular or other cross-section. Width ledgers 4B are further preferably embodied such that the upper surface of the upper connecting element 4BA lies below, preferably substantially below, the height of the upper side of connecting part 4LA so as not to obstruct the passage of a displaceable platform 3. The connecting ledger is preferably also of the double ledger type and consequently also comprises a connecting part 4BB which can for instance be embodied as a cylindrical rod. Connecting parts 4BA and 4BB are preferably connected to each other by means of support structures 4B3. This connecting ledger 4B is described in more detail in FIGS. 6A-6F.

(40) FIGS. 7A and 7B show in more detail the coupling means which will preferably be used for width ledgers 4B. Thus also shown in FIG. 7A is the recess or opening 4L4U, 4B4U arranged at the bottom of the bracket to allow the passage of nuts or bolt heads.

(41) FIG. 8 shows an alternative coupling means which can be used for both lengthwise ledgers and width ledgers for the purpose of coupling to the threaded elements of the support blocks or support ledgers. The coupling mean shown here is of the bracket type and can preferably be used for width ledgers 4B. The coupling means can also comprise a single plate, this preferably for the lengthwise ledgers. There is then no recess 4L4U. Slots 4LS1, 4PS1, 4LS2 and 4PS2 can be identical to those described for FIG. 8. The coupling means comprises an upper slot 4LS2, 4BS2 which extends from a lateral edge of the coupling plate (bracket) and which comprises an entry opening lying at the height adapted to correspond to the predetermined position of the second threaded rod of the support block or the support block ledgers relative to the first threaded rod. In these embodiments of a second type for the second slots the upper slot further extends in an upward curving circular arc. The curvature of the circular arc corresponds to the rotation of the ledger round the first threaded rod. The coupling plate therefore preferably comprises on the rear side a recess 4LS24, 2BS24 which can receive, close to the outer end of the circular upper slot 4LS2, 4BS2, a nut which is coupled to the upper threaded rod when this nut is screwed on. Undesired release of the coupling resulting from a possible undesirable rotation of the ledger can in this way be prevented.

(42) FIG. 9A shows a front view of a coupling plate such as can be comprised at the outer end of a support ledger 50, half support block 51 or extension ledger 4VL. In order to illustrate the idea a head 504 of a support ledger 50 is for instance considered (see also FIG. 3A). This also corresponds mutatis mutandis with the configuration of threaded rod elements on a narrow support block 52. FIG. 9B shows a cross-sectional view along the line A-A in FIG. 9A. The bolts or threaded rod elements 5043 are arranged in holes 5041 in plate 504. Holes 5041 comprise for this purpose screw thread 5042 into which the first longitudinal part of bolt 5042 with a first diameter d1 can be tightened. A second longitudinal part of the bolt has a broader diameter d2, wherein the transition from the part with diameter d1 to the part with diameter d2 is stepped. The part with diameter d2 hereby provides for a blocking effect from a determined screw-in depth of the bolt into opening 5041. The bolt does not comprise a classic head here but comprises an opening 5046, for instance a hexagonal opening, but also any other known form of opening, in which a screwing means such as a screwdriver or key can engage in order to realize screwing-in of the bolt. A nut 5045 can then co-act with a screw thread on the protruding part of the bolt.

(43) The skilled person will appreciate that alternative systems of fastening the bolt are possible. The bolt can optionally also be arranged through an opening in a plate and secured by means of a nut or other element with screw thread along the rear side of the opening.

(44) FIGS. 11A to 11E illustrate the extension ledger 4VL. Such a ledger can be used to later erect on for instance a narrow support block 52, or on the side without ledger part in a half support block 51, a scaffold section with a length substantially greater than the length of extension ledger 4L. For this purpose the extension ledger comprises at a first outer end a first coupling means 4VL41 and at a second outer end a second coupling means 4VL42. Two connecting parts 4VLA (upper) and 4VLB (lower) connect these two coupling means and are connected to each other by means of support 4VL3. The structure at the second outer end 4VL42 corresponds to the structure of coupling means 504 of the ledger as described for instance in FIGS. 5A and 5B, 8B. The structure at the first outer end corresponds for instance to the structure at the outer end of the ledger part of a support beam ledger as for instance described with reference to FIG. 3A or 4A.

(45) Note that the coupling means of the longitudinal and width ledgers as described in the present invention can also be coupled to each other by means of bolts and nuts. This allows, if desired, mutual coupling of two or more longitudinal or width ledgers, and so the formation of longer ledger elements.

(46) In the description of determined embodiments according to the present invention different features are sometimes grouped in a single embodiment, figure or description thereof, with the purpose of contributing toward the understanding of one or more of the different inventive steps. This may not be interpreted as if all features of the group are necessarily present in order to solve a specific problem. Inventive aspects are not to be found in all features of such group features present in the description of a specific embodiment.

(47) While some of the embodiments described herein comprise some, but not other, features included in other embodiments, combinations or features of different embodiments are intended to lie within the scope of the invention and to form different embodiments, as would be appreciated by the skilled person.

(48) While the principles of the invention have been described above in respect of specific embodiments, it must be clearly understood that this description is given only by way of example and is not limitative for the scope of protection defined by the appended claims.