A SCAFFOLD, UPRIGHT AND CONNECTING ELEMENT FOR A SCAFFOLD, AND OTHER SCAFFOLDING ELEMENTS

The present invention relates to the field of scaffolds.

Different types of scaffolds and corresponding uprights, ledgers, diagonals and further scaffold elements exist nowadays. A common scaffold is the scaffold of the so-called "Layher" type, as described in for instance EP 0389933 Bl. This scaffold comprises uprights which comprise substantially round tubes and which comprise a rosette at the top, which is fixed around the round, tubular upright by being fixedly welded thereto. This rosette protrudes laterally from the upright and is provided with holes in which ledgers and diagonals can engage. These ledgers or diagonals are typically further locked by blocking the ledger or diagonal with a cotter in the corresponding hole of the rosette. These rosettes are typically arranged along an upright at intervals of 50 cm. For scaffolding constructions the space between two floors lying one above the other is substantially fixed. This distance amounts typically to 2 metres. This fixed distance is typically defined in the industry, but can vary according to the geographical location and the average height of the corresponding inhabitant. There is for instance a tendency in the Netherlands to set this distance at about 2.16 metres. The uprights of the "Layher" type and many other existing types of scaffolding therefore have no flexibility in the sense that lesser distances than the predetermined distance (typically of for instance 2 metres) can be constructed between two floors lying one above the other.

The holes in the rosette of the above mentioned upright of the "Layher" type are also limited in number. Eight holes are typically arranged in the rosette, which are arranged

around the upright at equally distributed angular distances (45 degrees) . Four of these holes then serve for hooking in of the ledgers, while the other four holes, lying between the first four holes, serve for fixedly hooking in of diagonals or other ledgers. This means that, for scaffolds which consist of at least two mutually adjacent scaffold sections and wherein it is necessary for both sections to be placed at a determined angle, only predefined angles are possible which correspond to the holes in the rosettes of the "Layher" upright (directions of 45 degrees relative to the ledgers along the transverse direction of the upright) . Slight variations in these angles are sometimes still possible, although the range of attainable angles is always discontinuous and/or incomplete.

Since the "Layher" uprights further comprise external parts or protrusions, they take up a relatively large amount space and thus require a relatively large amount of stacking space. One consequence hereof are high transport costs for this type of scaffolding.

In a scaffold of the "Layher" type the ledgers and/or diagonals and/or other elements which have to be coupled to the upright are further locked by means of a cotter, which must typically be arranged or struck further into the opening by means of a hammer. This entails the risk that the hammer needed may be dropped during erection of the scaffold.

When a rosette is damaged there is moreover damage to the whole upright, since the rosette is fixedly integrated with the upright in the case of a "Layher" upright. The locking of for instance a ledger in the "Layher" upright may further also be simply forgotten, this entailing further safety risks.

UK 1058971 describes a connector for scaffolding.

It is an object of the present invention to provide a scaffold, upright, connecting elements and other scaffolding elements for coupling thereto, which obviates at least one of the above stated problems .

In this description the terms "vertical" and "horizontal" are used, as is the expression "at the same height" . These terms must be interpreted as follows; the direction running substantially parallel to the force of gravity is the vertical direction, while the direction perpendicularly of this direction is the horizontal direction. The height can be seen as the height relative to the earth' s surface for a surface which is considered substantially flat. For a non- flat surface the height can be defined as the height relative to the mass centre of the earth. When this terminology is used in the context of an upright per se, the height refers to the distance relative to the outer end of the upright which is adapted to be directed downward during use .

When a first element and a second element, for instance "surface area" or "cross-section" , have "substantially" the same size, this can mean that they have the same size or that they have the same size within the accuracy of the production processes of the corresponding objects. The term can also indicate a systematic, small, but in its context significant difference in size between the first and the second element. The skilled person will recognize the correct meaning of this phrasing from its context. The cross-section of a spigot, which has "substantially" the same size as the hole in which this spigot must be arranged,

must thus always be just slightly smaller than the cross- section of the hole.

The fixing with a pin or blocking with a pin ["caler" in French] are specific forms of locking. Depending on the context where the terminology is used, the wider term "locking" can also be used, as will be appreciated by a skilled person.

The term "coupling means" refers to a means for coupling.

Such a means can be a jaw. A "fork tooth" is one jaw of two or more jaws. A claw is a jaw which comprises at least one recess which is adapted for coupling over the edge of the tube .

A first aspect of the present invention comprises a scaffold comprising at least one upright and one connecting element (for instance placed substantially non-vertically) , the uprights and connecting elements having the form of the tube type, wherein the upright has at least one opening and wherein an outer end of the connecting element comprises a first coupling means which engages in this opening.

The connecting element (for instance placed substantially non-vertically) can for instance be a ledger or diagonal.

According to preferred embodiments of the present invention, the upright further comprises at least a second opening in which one connecting element comprises a coupling means which engages in these two openings.

According to preferred embodiments of the present invention, the first and the second opening are situated on opposite sides of the upright.

In preferred embodiments of the present invention these first and second openings can be situated at substantially the same height.

In preferred embodiments the scaffold comprises an upright which further comprises at least a third and a fourth opening, wherein the third and the fourth opening lie in line with respectively the first and the second opening in the longitudinal direction of the upright, wherein the third and the fourth opening are further situated substantially at the same height and wherein the coupling means of the connecting element comprises at least two fork teeth which engage on the four openings, wherein the first fork tooth engages on the first and the second opening and the second fork tooth engages on the third and the fourth opening.

According to further preferred embodiments of the present invention, the first and the second opening are situated mutually in line along a direction substantially parallel to the longitudinal direction of the upright.

In preferred embodiments the coupling means of the connecting element comprises at least two claws.

In preferred embodiments the coupling means of the connecting element comprises at least one claw.

In preferred embodiments the first and the second opening have the same form.

In preferred embodiments the upright can have a substantially circular cross-section.

In another preferred embodiments the one or more uprights can be of substantially rectangular cross-section and

consequently have substantially four longitudinal side surfaces, wherein at least two of these side surfaces are provided with at least two holes and are directed in the direction of adjacent uprights.

A scaffold preferably comprises more than one ledger and more than one diagonal. A typical scaffold comprises a multiple of two uprights which are stacked adjacently of and above each other and which are mutually connected using ledgers and diagonals connected to the respective uprights.

Preferred embodiments of the present invention comprise at least uprights placed and coupled mutually in line, wherein the uprights are connected by a connecting spigot which is fixed along a first of its outer ends in one of the outer ends of the one upright, and wherein the second of its outer ends is arranged in an outer end of the second upright. The respective first and second of the outer ends of the spigot can preferably be respectively a first half and a second half of the spigot.

This connecting spigot can comprise at least one opening at the position of a corresponding opening in the upright.

According to embodiments of the present invention, the opening in the connecting spigot is larger than the opening of the corresponding opening in the upright, preferably along the longitudinal direction of the upright, such that the space around and close to the internal edge of the corresponding opening in the tube or upright is left clear.

In embodiments the scaffold comprises two identical uprights according to embodiments of the present invention which can be mutually connected in that they are placed and coupled adjacently of and next to each other, for instance by

placing a blocking means through corresponding holes of the first and adjacent second scaffold. This allows strengthening of the scaffold construction in general or at the very least locally, and thus an increase in the load- bearing capacity of the scaffold.

According to a second aspect of the present invention, an upright of the tube type is shown which is adapted to form part of a scaffold, wherein the upright comprises at least one opening which is adapted to receive a coupling means of a connecting element (for instance to be placed substantially non-vertically) .

In preferred embodiments the upright comprises at least two openings which are adapted and arranged to receive a coupling means of a connecting element.

These first and second openings can be situated on opposite sides of the upright.

In preferred embodiments the first and the second opening are situated mutually in line along a direction substantially parallel to the longitudinal direction of the upright .

In preferred embodiments the openings are substantially of the oval or egg-shaped type and the longitudinal axis of the opening runs substantially parallel to the longitudinal direction of the upright. The rounding of the oval or egg- shaped holes or openings can improve the fixation of a connecting element, such as for instance a ledger or diagonal, in the opening. In other embodiments the openings are rectangular or square or have another suitable form.

In preferred embodiment the uprights have a substantially circular cross-section.

In more preferred embodiments of the present invention the uprights have a substantially rectangular or square cross- section and as a result comprise (or are substantially constructed from) substantially four longitudinal side surfaces. Such uprights are generally stronger (they can bear more load without bending or being damaged) , among other reasons because of their specific form and the presence of a relatively larger quantity of metal in the upright as compared to for instance a corresponding round upright .

In preferred embodiments the upright comprises at least two columns of openings of the same form along the longitudinal direction of the upright, in at least two different of four directions chosen to be at a right angle to each other along the cross-section of the upright. In the case of uprights of square or rectangular cross -section the at least two different directions preferably correspond to the directions which are at a right angle to two of the four longitudinal side surfaces of the upright. In other words, the upright comprises at least two columns of identical openings along the longitudinal direction of the upright which are separated from each other by a rotation angle around the longitudinal axis of the upright which amounts to a multiple of 90 degrees. In preferred embodiments this angle amounts to 180 degrees.

In further embodiments the upright comprises three columns of identical openings along the longitudinal direction of the upright, of which the columns of each pair of columns are separated from each other in each case by a rotation angle around the longitudinal axis of the upright which

amounts to a multiple of 90 degrees. In the case of uprights of square or rectangular cross- section, the three different directions preferably correspond to the directions at a right angle to three of the four longitudinal side surfaces of the upright .

In preferred embodiments of the present invention the upright comprises four columns of openings of the same form along the longitudinal direction of the upright in four directions chosen to be at a right angle to each other along the cross -section of the upright. In the case of uprights of square or rectangular cross-section the four different directions preferably correspond to the directions at a right angle to the four longitudinal side surfaces of the upright. In other words, the upright comprises four columns of openings of the same form along the longitudinal direction of the upright which are separated from each other by a constant rotation angle around the longitudinal axis of the upright which amounts to 90 degrees.

In the case of uprights of square or rectangular cross- section the columns of holes present are preferably centred on the longitudinal side surfaces in which they are comprised. These uprights preferably have a width of for instance about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, although greater and smaller widths are not precluded. Each of the longitudinal side surfaces preferably comprises only one column of openings .

In preferred embodiments the adjacent openings of the same form in the same column are situated in each case at a constant mutual distance. The distance between two successive holes in the same column preferably amounts to more than 2 , more preferably more than 3 , or more than 5 or more than 10 cm. This distance preferably amounts to less

than 30 cm, less than 50 cm, less than 54 cm, less than 1 m, less than 2 m, less than 2.16 m. This distance can for instance amount to 3, 3.2, 4, 5, 6, 7, 8, 9, 10, 20, 30 cm.

Close to the outer ends of the upright the final openings are preferably placed a distance from the outer end which is substantially equal to half the constant distance between the holes . This also ensures a constant distance between the holes at the transition between for instance two coupled uprights lying one above the other (between the final hole of the one upright and the first of the following upright) .

In preferred embodiments the upright further comprises a connecting spigot which is fixed along a first of its outer ends in one of the outer ends of the upright.

This connecting spigot comprises at least one opening at the position of a corresponding opening in the upright. This opening in the connecting spigot is preferably larger than the opening of the corresponding opening in the upright, preferably along the longitudinal direction of the upright, such that the space close to the internal edge of the corresponding opening in the tube is left clear. The presence of the spigot in one of the outer ends of the uprights does not therefore prevent the upright being compatible at the position of the spigot with the coupling means of for instance ledgers according to embodiments of the present invention. Despite the presence of the spigot the wall thickness of the upright would indeed be equal around the opening to the wall thickness of the upright at a position where no spigot is present. It can be noted that, in accordance with the embodiment of the hook- in system (i.e. coupling means), it may be sufficient for this space which is left clear to be situated only at the bottom of the edge of the opening, or only at the bottom and top of the

opening. In other embodiments it could be sufficient for these spaces which are left clear to be situated (laterally) on the openings on the sides.

In embodiments of the present invention the spigot can be provided with holes at the position of any hole or opening present in the corresponding outer end of the upright .

It can be noted that two identical uprights according to embodiments of the present invention can be coupled to each other in a scaffolding construction by placing them adjacently of each other and coupling them, for instance by placing a blocking means through corresponding holes of the first and adjacent second scaffold. This allows strengthening of the scaffold construction in general, or at the very least locally, and thus an increase in the load- bearing capacity of the scaffold.

It can further be noted that the uprights according to embodiments of the present invention preferably have a smooth outer surface which comprises no protrusions. This reduces for instance the volume necessary for storage and transport. The uprights preferably have a constant cross- section perpendicularly of the longitudinal direction of the upright. The uprights are preferably hollow. They preferably comprise only limited, or more preferably no internal strengthening structures .

A third aspect of the present invention comprises a connecting element (for instance to be placed substantially non-vertically) for a scaffold, which comprises a coupling means which is adapted for coupling to a substantially tubular upright, wherein the coupling means is adapted to engage on at least one opening in the upright.

In preferred embodiments of the present invention the coupling means comprises at least one claw adapted for arranging in the opening and for hooking fixedly behind the opening in the upright.

In preferred embodiments of the present invention the coupling means is adapted to engage on at least two openings in the upright. This generally results in a better fixation than when only one opening is engaged.

In preferred embodiments the coupling means comprises two claws which are adapted to engage on the two openings situated on the same side of the upright.

In preferred embodiments the coupling means comprises two claws which are positioned fixedly relative to each other and which, after the hooking in, engage behind the underside of the respective openings.

In preferred embodiments the coupling means comprises two claws which are adapted to be pushed apart after being arranged in the respective openings, so that the two claws engage on the underside of respectively the lower and upper side of the top opening. In preferred embodiments the coupling means comprises two claws which are adapted to be pulled toward each other after being arranged in the respective openings, so that the two claws engage on the underside of respectively the upper and lower side of the bottom opening.

In preferred embodiments the coupling means is adapted to form a throughfeed connection through the first and the second openings of an upright situated on opposite sides of the upright .

In preferred embodiments the connecting element further comprises at least one hinge or swivel coupling, or means with similar functionality. This can facilitate hooking-in of the connecting element, certainly when the connecting element, which typically comprises a coupling means at each of its two outer ends, is already coupled to a first upright and must be further coupled to a second upright . The presence of a hinge or swivel coupling or other hinge means with similar functionality further allows orientation of a first part of the connecting element relative to a second part of the connecting element at any random horizontal, vertical or solid angle, wherein the two parts are situated on different sides of the hinge element. This solid angle can be defined by the skilled person in the spherical coordinates (rho, theta) : in an right-angled coordinate system (X, Y, Z), in which the first part of the connecting element runs along the X-axis and the hinge means is situated in the origin, theta refers to the angle of the second part with the X-axis in the X-Y plane and rho to the angle of the second part with the Z-axis. The first and the second part of the connecting element typically comprise two, or the two, tube parts comprised in the upright. This allows the possibility of a continuous, and in determined embodiments a full, horizontal, vertical or spatial spectrum of angles between two adjacent, connected scaffolding sections. This allows as a result the erection of scaffolds or work platforms close to a non-flat and/or curved surface or facade (for instance of a building, such as for instance a church, or storage tank of the cylindrical type) . This can for instance also allow compensation for determined height differences of the ground.

In preferred embodiments the element comprises a ledger or diagonal for a scaffold. In preferred embodiments the ledger can be a reinforced ledger in the sense that the two

coupling means of the ledger can be fixed to more than one tube element, such as for instance two tube elements, which mutually connect the coupling means .

In preferred embodiments the length of the ledger, including coupling means, is unchanging or constant, which can enhance the load-bearing capacity of the ledger. In preferred embodiments the coupling means, claws or fork teeth are fixed relative to the tube element of the ledgers.

In preferred embodiments the coupling means of a connecting element are constructed such that they allow further sliding into the relevant openings of the uprights, this over a great enough distance to ensure that, when the first coupling means is slid further into the relevant openings of a first upright of the scaffold, the second coupling means can be removed from the relevant openings of the second upright .

In preferred embodiments the connecting element further comprises an integrated locking means for locking the connecting element. This locking means can preferably be activated by an integrated activating means. In preferred embodiments the two locking means typically comprised in a connecting element can be activated by a single activating means coupled to the two locking means .

The ledger, diagonal or other components can be locked either automatically or manually during the hooking- in. In the case of automatic locking a blocking can be provided in the ledger, diagonal and the like, which automatically snaps into place when the connection is arranged in the connecting hole. The unlocking will take place manually by means of a shaft with handle, hook or rotary knob with which the blocking can be removed.

Another possibility is manual locking. A handle, lever, hook, rotary knob or other component can be provided for this purpose.

This automatic locking has the great advantage that it is impossible to forget to lock a component, this resulting in increased safety. Locking can take place on:

- one or more sides of the opening; - one or more surfaces on the inside of the opening and adjacent to the opening,-

- one or more surfaces on the outside of the opening and adjacent to the opening.

It can be noted that it is also possible to envisage other elements which can be used in combination with a scaffold or upright according to embodiments of the present invention, which comprise a coupling means adapted to engage on one or more holes or openings of an upright according to the present invention. Such elements are for instance, though not only, consoles, lattice girders (comprising latticework based on girders and connecting elements between such girders), edging boards and railings.

In a fourth aspect of the present invention a foot jack is further provided which is adapted to co-act with an upright according to the embodiments of the present invention. This foot jack is preferably also adapted to co-act with a connecting element according to the embodiments of the present invention.

It can be noted that different coupling means can be combined in a scaffold, or in a section of a scaffold, or for a connecting element. When considering a scaffold with horizontal rectangular sections, coupling means can thus be

used in the width direction (typically a side part perpendicularly of a wall) of the sections which are different from those used in the longitudinal direction (typically the front part, for instance parallel to a wall) of the sections.

Ledgers can comprise the same coupling means at the two outer ends, although these can also differ depending on the movement required to cause the coupling means to engage on a second upright after engagement with a first upright has already been realized.

The same applies for the diagonals.

Determined coupling means, which will be described in detail hereinbelow, can further be adapted more for use in diagonals, while others can be adapted more for use in ledgers .

In embodiments of the present invention a connecting element can comprise on only one of its outer ends a coupling means which is adapted to engage on one or more openings in the upright. The other, free outer end of the connecting element (in some embodiments the free outer end of the tube connected to the coupling means) can be adapted for coupling to a further tube, which can in turn optionally be coupled again to a subsequent tube, etc. By finally providing a second coupling means at the other outer end of the mutually connected series of tubes (for instance by again providing a connecting element with only one coupling means) relatively great distances can be spanned between two non-adjacent scaffold sections which are situated next to each other, without uprights having to be arranged below the bridging. In embodiments of the present invention the tubes used for the bridging can be uprights. In embodiments of the present

invention coupling means are provided according to embodiments of the present invention which are adapted to couple in an outer end of an upright according to the present invention (for instance by sliding in or over an outer end of the upright and being further locked by means of for instance a pin) and which are further adapted to engage in an opening in the side of the upright.

When different connecting elements must engage at the same height of an upright, it is necessary to take into account the relevant coupling means. In the example of a rectangular upright which comprises four surfaces which are each provided with holes: some coupling means hook in on one side of the upright and also allow similar coupling means to engage afterwards in the other free openings at the same height of the upright, since the necessary space remains clear internally in the upright. They for instance also allow another coupling means of the "throughfeed connection" type to be formed at the same height. When two coupling means of the "throughfeed connection" type are for instance used, they cannot be coupled to the scaffold at the same height .

The embodiments of the present invention do however readily allow arranging of the different connecting means at levels which differ little (for instance about 3 cm) without significantly weakening the stability and strength of the scaffold.

In embodiments according to the present invention there are also provided bent ledgers of the tube type which further have an (in each case downward or upward) bend on each side close to the coupling means, so that the tube of the bent ledger nevertheless ends substantially at a higher or lower level than that where the coupling means of the bent tube

are coupled to the upright, which for instance corresponds to the level of another ledger in a direction perpendicularly of the direction of the bent ledger.

In further embodiments of the present invention of the

"offset ledger" type, the coupling means of the "throughfeed connection" type, in particular the jaws or fork teeth thereof, can comprise a cross-section substantially corresponding to one of the two equal lateral halves of the openings in the upright (for instance vertical or horizontal halves) . This would still allow coupling of two coupling means of the throughfeed connection type to the upright at the same height and, in addition, in the same pair of opposite holes.

It can be noted that the scaffolds, uprights, connecting elements and jacks according to embodiments of the present invention can also be used for supporting and shoring, as can be the case for instance in concrete constructions. It can be advantageous for this purpose that different uprights can be coupled mutually in line or adjacently of each other.

The blocking means, such as for instance single pins which can be used in combination with embodiments of the present invention, are preferably of the elongate type and preferably have a constant cross-section which is substantially equal (typically slightly smaller, i.e. leaving clear a space of 0.5 mm) to the openings in the uprights. One of the outer ends of the single pins can be adapted to be able to exert a force thereon in simple manner so as to thus facilitate the removal of the blocking means from for instance an upright. It can for instance comprise an annular structure connected to the rest of the pin.

Other blocking means of the "double pin" or "multiple pin" type can comprise more than one pin, which together form a fork structure and wherein each pin preferably corresponds to the single pin according to embodiments of the present invention. The different pins comprised in such blocking means can be connected to each other via a connecting piece. They can for instance be formed integrally with the connecting piece. The connecting piece can further be adapted to exert a force thereon in simple manner so as to thus facilitate the removal of the blocking means from for instance an upright . It can for instance comprise an annular structure or handle- like structure.

It can further be noted that each time the term "means" is used, this can refer to "device" or "apparatus" ; the

"coupling means" can thus also be referred to for instance as a coupling device or coupling apparatus.

The above stated and other advantageous features and objectives of the invention will become more apparent and the invention better understood as a result of the following detailed description when read in combination with the respective drawings.

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

Reference symbols are chosen such that they are the same for similar or the same elements or features in different figures or drawings.

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 must be deemed as non- limitative .

Determined elements or features may for instance be shown out of proportion or scale in relation to other elements .

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 solely in all features of such group features present in the description of a specific embodiment.

Figures 22A, B, C, D show a scaffold (1) , uprights (2) and connecting elements (31 (311, 321 in the length direction of the scaffold sections) , 32 (322, 312 in the width direction of the scaffold sections) ) according to embodiments of the present invention. Figure 22A shows a front view of such a scaffold, while figure 22B shows a perspective view of the same scaffold, figure 22C shows a side view of the same scaffold and figure 22D shows a top view of the same scaffold. The scaffold is constructed from a plurality of uprights, typically a multiple of two uprights, which form scaffold sections which can be disposed and coupled adjacently of each other or above each other. Uprights (2) are mutually connected by means of ledgers and diagonals in order to thus complete the sections and impart strength and stability to the whole scaffold construction. According to embodiments of the present invention, uprights (2) from which the scaffold is constructed comprise an array of prearranged openings or holes (7) . These openings or holes preferably take the same form and are arranged at preferably constant distances from each other. This constant distance can for instance be chosen at about 3 cm. In order to enable

an easier estimation of the height level of a hole, for instance in order to simplify the horizontal placing of the ledgers between two uprights, the holes (for instance in a column) can be marked in systematic manner, such as for instance numbered or marked with a regular repetition of a successive series of symbols (for instance square / circle / triangle / square / ... ) . The uprights of the present invention as shown in figure 22B are preferably such that they have a square or rectangular cross -section. Such a rectangular or square upright typically has a greater load- bearing capacity than for instance a round upright, so that internal strengthening structures in the uprights can be avoided. Each of the four surfaces which define the upright are preferably provided with such columns of holes. The ledgers and diagonals which are adapted for use in such scaffolds and in combination with the uprights according to embodiments of the present invention comprises coupling means 4 (4A, 4B) which are adapted to engage in at least one opening of the upright. These coupling means can further also be adapted to engage in two openings situated on the same side of the upright, or in two openings situated on opposite sides of the upright. The coupling means can further also be adapted to engage in more than two openings, for instance in four openings, wherein the four openings consist of two pairs of opposite openings, wherein the pairs are aligned along the longitudinal direction of the uprights . The uprights are preferably further adapted for coupling to an overlying or underlying upright. Also provided at the bottom of the scaffold are foot jacks (6), as it were the feet of the scaffold, which are adapted to co-act with the upright and connecting elements according to embodiments of the present invention.

Figure 23 shows possible embodiments of the holes which can be arranged in each of the four side surfaces of the

upright. These holes are preferably of the oval type, but may also be rectangular or square. They may also have other shapes, as will be appreciated by the skilled person. Openings (7) shown in figure 23 consist substantially of four sides (71, 71' , 72 , 72 ' ) together defining an elongate opening, the longitudinal direction of which is substantially parallel to the longitudinal direction of the upright. The connection between these four sides can be angular, or rather rounded. The upper and lower sides of the opening (71, 71') can for instance be straight (so without curvature), while the sides of the opening (72, 72') can be curved, wherein this curvature is preferably convex and is so directed outward. The sides of the opening being curved outward can facilitate or improve the fixing of a coupling means according to embodiments of the present invention.

This shape can also facilitate the insertion of a claw, jaw or fork tooth, and the shape of the opening can thus be chosen as a function of these characteristics.

Upper side 71 and lower side 71' of opening 7 can also be curved, wherein this curvature is preferably convex and directed outward.

In preferred embodiments of the present invention the transition between the lower part and/or upper part and/or side part of the holes and the inner surface and/or outer surface of the upright is at least partially rounded or curved.

The respective curves of the lower part and/or upper part of the holes can be such that hooking in and/or securing of coupling means in the upright is facilitated or made possible.

The openings can have a height or length of about 15, about 20, about 25, about 30 mm, about 35 mm, about 40 mm or about 45 mm. They can for instance have a height of 30.5 mm. The openings can have a width which varies but is for instance on average about 15 mm, or about 20 mm, or about 25 mm.

Figures 24A and 24B show an upright (2) according to embodiments of the present invention. This upright has a substantially square cross-section, and comprises on each of its side surfaces columns of holes (7) of the same form which are placed at a fixed distance from each other along the longitudinal direction of the upright, and preferably such that the longitudinal axis of each opening is also aligned with the longitudinal axis of the upright. At the top the upright can comprise a connecting spigot (28) which is fixed along a first of its outer ends (282) in one of the outer ends of the one upright, while the second of its outer ends (281) is adapted to be arranged in an outer end of another upright. The two outer ends are typically connected to each other directly or connected via a widening part 29. The connecting part can comprise a surface running obliquely relative to the longitudinal direction of the upright, and thus provide a continuous transition between the two parts, although the transition between the two parts can also take place via a discontinuous step in which the diameter of connecting spigot 28 is stepped at the position of widening part 29. At the position of the openings in upright (7) the connecting spigot also comprises openings (7*) which lie centred relative to openings (7) . The opening in the connecting spigot is here then the opening of the corresponding opening in the upright, substantially along the longitudinal direction of the upright, such that the space around and close to the internal edge of the corresponding opening in the tube is left clear. Openings 7 and 7* are shown equally wide here, although this is not

strictly necessary. Openings 7 and 7* can also have a different general shape, or not be isomorphic.

In order to enable placing of the uprights on each other a spigot can thus be provided which is pressed into the upright and locked by means of for instance rivets (bolts or welds) . Several millimetres outside the upright the spigot will have the same dimensions as the inside of the tube in order to obtain a closing connection. The spigot can preferably be provided with holes which correspond to the holes of the upright and the recesses for connection to the upright .

In other embodiments shown in figure 28 connecting spigot 28 is separate from the upright and adapted to slide into or over the upright, having for this purpose a constant, slightly smaller or slightly larger diameter than the upright, and further described as in the fixed spigot. By means of for instance one, two or more pins which are arranged through holes in the spigot and uprights, this spigot 28 can then be placed in or over the outer ends of the uprights to be fixedly connected. Note that the holes in the spigot, when they are arranged in the uprights, are similar to the holes described for the fixed spigot. When however the spigot slides over the uprights, the holes are preferably also such that the engaging of the coupling means in the holes of the upright is not impeded at the position of the spigot (engagement in this case takes place through the spigot) . These holes are then similar to holes 7** as described below in respect of the embodiments R for a foot jack. Such spigots can also be used to connect different uprights in a bridging construction between two non-adjacent scaffold sections situated next to each other, as for instance described above.

Note that the openings in spigots 28, which are situated close to the outer ends of the spigots, for instance the first and second holes (on all sides of the upright where holes are provided) can be of the same size as the holes in upright 7. This allows fixing of the upright and the spigot with a pin adapted for use with holes 7 (having substantially the same cross-section and being adapted for arranging in holes 7) . The other holes that are present can then be of the type 7* and 7**. This can be the case for both the fixed and the separate spigots and, in the case of the separate spigots, for the embodiments in which the spigot is situated internally on the uprights as well as the embodiments in which the spigot is situated on the outside of the uprights. In the embodiments with a fixed spigot in an outer end of the upright only the openings close to the non- fixed outer end of the fixed spigot can be of the type 7 (for instance the first hole or the first two holes close to this outer end) , while the other holes can be of the type 7* .

Figures 29A, 29B, 29aA and 29aB show a spigot according to embodiments of the present invention. This spigot is similar to the spigot shown in figure 28 and is provided for arranging at the outer end of an upright so as to thus enable a coupling of an upright to be arranged horizontally to a first vertical upright. Spigot 28 can hereby slide either internally into the upright for placing horizontally (figure 29aA, figure 29aB) or slide externally over the upright for placing horizontally (figure 29A, figure 29B) . As also described for the separate spigot, which was also described in figure 28, the spigot in this embodiment also comprises holes 7** or 7*. These spigots can further be coupled to the vertical upright by means of a fixing mechanism 531 which comprises a part 5311 which can be arranged through a hole in the vertical upright and which

can be provided with screw thread (or other suitable self- locking means) on one of its outer ends, onto which a nut or similar element 5312 can be screwed so as to thus realize a fixing of the spigot to the vertical upright. Part 5311 preferably comprises a cross -section substantially equal to the surface area of opening 7. Part 5311 is preferably fixed (for instance fixedly welded) to spigot 28 at its other outer end. Note that the openings close to the free outer end of the spigot according to figures 29A, 29B, 29aA and 29aB can also correspond to openings 7 in the upright as described for the separate spigot, but that the further openings in this spigot preferably correspond to openings 7* or 7**, as described for the separate connecting spigot. The length of part 5311 can substantially correspond to the width of an upright or to a multiple of, for instance double, the width of an upright. This allows the fixing on one or more uprights .

The locking of uprights situated one above the other can take place by inserting a pin wholly through the spigot and the upright . Locking can however also take place through the ledgers, diagonals or other connecting elements, depending on the coupling means used.

The upright can also be locked automatically. A hook can herein engage in the spigot of the upright. The hook can be built in at the bottom of the uppermost upright, this at the position of for instance the uppermost hole of the spigot of the lowest upright. When upright and spigot are slid into each other, the hook will automatically snap into place behind the spigot owing to the force of gravity or by means of a spring means (such as for instance a spring) , whereby the upright is automatically locked without performing an additional operation. For the purpose of unlocking the hook will have to be pushed through the hole.

Figure 1 shows a coupling means (4) according to embodiments of the present invention. The coupling means can be connected to the rest of the connecting element in different ways by means of a fixing part 5. They can preferably be welded, riveted or screwed, or be joined to the rest of the connecting element in other ways known to the skilled person, such as for instance using one or more rods or tubes (31X, 31Y, 32X, 32Y) which mutually connect the for instance two coupling means of the connecting element. Holes 8 can be provided for this purpose in this connecting element, for instance in fixing part 5. The figure, and similar further figures, show a rear view and a front view of the coupling element on respectively the left and right-hand side. A top view of the coupling element is shown at the bottom. A side view of the coupling element is in the centre. The coupling element comprises two claws 9 and 9 ¹ which are adapted to engage in two holes on the same side of the upright. The claws (or, in other embodiments, jaws or fork teeth) can be connected to fixing part 5 via a connecting body 90. Body 90 can be integrated and can be formed from one piece with the claws, fork teeth or jaws and/or with connecting means 5. The coupling means is adapted particularly to be arranged in two openings in the upright and to then hook fixedly into the edge of these openings, in particular the lower edge of the relevant openings in the upright, by means of a recess 91 and 91' which define the claw. The coupling means is further provided with a locking means 12 which can be manually activated by means of a rod 10, which can end in an eye, runs through an opening 13 in body 90 and is connected on the other side to the block or locking means 12. The block is guided in its movement by a guide structure or rail 12A to which block 12 is preferably slidably coupled. After hooking into holes 7 of the upright, a space comes free between the top surface of the upper claw and the top side

of the opening, which space can be filled with the block or locking means 12. Figure 1 ' shows a perspective view of the same embodiment .

These coupling means are preferably constructed such that they allow further sliding of the connecting element of which they form part into the relevant openings of the uprights, this over a distance (for instance d) which is great enough to ensure that, when the first coupling means is slid further into the relevant openings of a first upright of the scaffold, the second coupling means can be removed from the relevant openings of the second upright. This can for instance be achieved by keeping the fork teeth on claws of the connecting means narrow enough so that their further inward passage through the openings of the upright still remains possible over a determined distance.

Figure IA shows a similar coupling means with double claw and manual locking, which is further provided with a pivot point (11) at the top situated close to upper claw 9 and between upper claw 9 and fixing part 5. These embodiments of the coupling means can preferably be used for connecting elements of the diagonal type. Pivot point (11) allows a vertical pivoting of the ledger. Figure IB shows a coupling means with double claw and manual locking, which is further provided with a pivot point 11 at the bottom situated between lower claw 9 ¹ and fixing part 5. This embodiment can preferably be used for connecting elements of the diagonal type. In determined embodiments a diagonal can comprise a first coupling means according to figure IA at its first outer end and a second coupling means according to figure IB at its second outer end. The first coupling means can preferably engage lower in the scaffold construction than the second coupling part. The locking by means of locking

means 12 preferably takes place on the other claw which is furthest removed from pivot point 11 or hinge 16V. Figures 1C, 1C , 1C ' show coupling means with a double claw 9, 9 ¹ and automatic locking 12, which can preferably be used for the connecting elements of the ledger type. These embodiments correspond to the embodiments of figures 1 and 1 ' , although they further comprise an automatic locking means 12B. The automatic locking means comprises for instance a spring 14 which is coupled to block 12 and which allows an automatic outward sliding of block 12 when space becomes free or is available for this purpose.

Figures ID, ID' and ID' ' show further coupling means according to embodiments of the present invention, wherein the locking takes place automatically and unlocking can take place simultaneously on both sides of the connecting element by making a single movement. A connection which makes possible the simultaneous unlocking along both sides runs through tube 3 IX. A centrally placed locking mechanism 1OA is connected for this purpose to the two coupling means in such a way that the two coupling means can be locked and unlocked together. This locking mechanism can be provided internally or on the outside of tube 31X.

Figures IE, IE' , IE' ' and IE' ' ' show a reinforced ledger according to embodiments of the present invention, in which a plurality of tubes, for instance two tubes 3IX and 3IY, connect the coupling means on either side of the ledger. These embodiments can produce an increased load-bearing capacity.

It can be noted that in embodiments of the present invention the load-bearing capacity of a floor can be increased by arranging under this floor more than one level of ledgers, which also support directly on each other. The support can

be realized by making use of one or more accessories adapted for this purpose. Such an accessory is described for use in a scaffold according to embodiments of the present invention comprising at least two ledgers, a first ledger situated parallel to and above a second ledger at a predetermined distance, with the feature that the accessory comprises two outer ends and is adapted at a first of its outer ends to engage on the first ledger and is adapted at a second of its outer ends to engage on the second ledger. The distance between the two points of engagement of the accessory can be substantially equal to the predetermined distance. The accessory is preferably of symmetrical construction. Because the distance between two successive holes in the upright can be relatively small, the accessories can be of relatively small size and the reinforcement of the ledger can also take place with limited impact on the degrees of freedom of the user. An example of such an accessory is a self -clamping plastic block. In other words, the use of such accessories creates a reinforced ledger in simple manner.

Figures IF and IF' show a coupling means with double claw and automatic locking which is adapted for manual unlocking. The coupling means locks automatically during hooking- in in that tilting element 15 has a form such that it is adapted to automatically perform a tilting movement around a pivot 14 while seeking balance, such that block 12 automatically hooks into the space which is left clear in the opening of the upright after the claws have hooked into the edge of the openings. The unlocking must take place manually here by moving the tilting element away from the upright by means of a preferably pivoting movement around a pivot 14. The coupling element locks automatically during hooking- in. The hook falls shut automatically due to a spring and/or its own weight and provides for locking. This unlocking can take place along one side as well as simultaneously along both

sides of the ledger through one movement. In the case of a simultaneous locking along both sides a connection will run through the tube (this can preferably be used for connecting elements of the ledger type) .

Figures 25, 25' , 25 ' ' , 25 ' ' ' , 25'''' show a similar coupling means according to embodiments of the present invention.

Note that tilting element 15 is placed internally here in the coupling means, for instance internally in a housing formed by claw 9 and body 90, although this is not strictly essential. The tilting element can also be arranged externally, for instance on the outside of claw 9 and/or body 90.

In figures IG and IG' the coupling means as shown in for instance figure 25 are further provided with a pivot element 16V allowing pivoting of the connecting element.

Figure 2 shows a coupling means of the "double throughfeed connection" type. Two jaws or fork teeth pass wholly through the upright, after which they can drop in the upright via recesses (91, 92, 91', 92') arranged in the bottom of the fork teeth. A locking is hereby already obtained in the horizontal direction. In order to lock the coupling means in its entirety, a manual locking can also be provided which can for instance be similar to the locking means described in the above embodiments . Figure 3 shows a further embodiment of the "throughfeed connection" type. The jaw or fork tooth passes wholly through the upright and engages at multiple locations (91', 92, 99) . A manual locking is further provided, and a pivot point is present which enables pivoting in vertical direction. Connecting part 5, for instance for ledgers, diagonals and consoles, here comprises for instance a plate

positioned at a right angle to the longitudinal axis of the coupling means and provided with one or more holes against which the tube or tubes can be fixed, such as for instance screwed. Figure 3' shows a perspective view of the same embodiment. Protrusion 92 is a point of engagement positioned on the outside of the upright above the second opening after hooking in of the coupling means through a first and then second opposite opening.

The point of engagement 91' fulfils a similar function as recesses 91' in other embodiments comprising one or more claws. The point of engagement 99 is preferably provided with a suitable rounding such that the insertion of the coupling means into the first and/or the second opening of the upright is made possible or facilitated. The point of engagement 99 can further rest on the underside of the second opening after being hooked into the upright. During placing of the coupling means the point of engagement 93 engages on the upper side of the second opening. A manual locking means is further provided, which consists of a block connected to a ring 12C which couples the block slidably to the coupling means.

Figure 4 shows another embodiment of the "throughfeed connection" type. The jaw or fork tooth here passes wholly through the upright and engages at multiple locations. A manual locking is further provided, and an optional pivot point is present in horizontal direction which allows the pivoting of the connecting element in horizontal direction. A threaded rod 5 is further provided for connecting ledgers, diagonals and consoles. Figure 4' shows a perspective view of the same embodiment.

Figure 5 shows a further embodiment of the "throughfeed connection" type. The jaw or fork tooth here passes wholly

through the upright and engages at multiple locations. Manual locking is provided and there is also a pivot point 11 or horizontal hinge 16M in order to enable the pivoting in horizontal direction. A connecting piece 5 for ledgers, diagonals and consoles is further also provided. Figure 5 ¹ shows corresponding side views of embodiments of figure 5. Figure 5'' shows a perspective view.

Figure 5A shows a coupling means of the "throughfeed connection" type. The jaw or fork tooth passes wholly through the upright and the locking takes place by means of a pin lying in perpendicular direction thereof wholly through the upright. Figure 5B shows a further "throughfeed connection" . The jaw or fork tooth passes wholly through the upright, after which it can drop into the upright via the recess arranged in the underside of the jaw or fork tooth. A locking in the horizontal direction is hereby already obtained. In order to lock the coupling means in its entirety a manual locking can also be provided. An optional pivot point 16H for pivoting in horizontal direction is further shown .

In figure 6 the jaw or fork tooth passes wholly through the upright and engages at multiple locations. A manual locking is provided and the pivot point allows the pivoting in horizontal direction. A connecting piece or connecting part 5, for instance for a square tube, is further provided. Figure 6 ¹ is a perspective view of the same embodiment.

Figure 7 shows a further "throughfeed connection" . The jaw or fork tooth passes wholly through the upright and engages at multiple locations. Figure 7 ' is a perspective view of the same embodiment .

Figure 8 shows a "throughfeed connection" in which the jaw or fork tooth passes wholly through the upright and engages at multiple locations. Manual locking is provided and an optional vertical pivot point 16V is present to enable the pivoting in vertical direction. Figure 8 ¹ shows a side view of the same embodiment. Figure 8'' shows a perspective view of this embodiment.

Figure 9 shows a further "throughfeed connection" . The jaw or fork tooth passes wholly through the upright and engages at multiple locations. Manual locking is provided. A pivot point is also present for allowing the pivoting in the vertical direction. Connecting means 5 is here a rectangular tube. Figure 9 ¹ shows a side view of the embodiment of figure 9. Figure 9'' shows a perspective view of the same embodiment .

Figure 9A shows a further "throughfeed connection" . The jaw or fork tooth passes wholly through the upright and the locking takes place by means of a pin in the direction at a right angle thereto. A pivot point for pivoting in vertical direction 16V is provided and comprises a connecting piece 5 for ledgers, diagonals and consoles.

Figure 9B shows a further "throughfeed connection" according to embodiments of the present invention. The jaw or fork tooth passes wholly through the upright, after which it can drop into the upright via recesses 91' and 92' arranged in the underside of the jaw or fork tooth. A locking is hereby already obtained in the horizontal direction. In order to lock the coupling means in its entirety a manual locking 12 can also be provided. A pivot point is also provided in the vertical direction 16V, which is further provided with a connecting piece for ledgers 5, diagonals and consoles.

Figure 10 shows a further embodiment of the present invention of the "throughfeed connection" type. Figure 10' shows side views of this embodiment. Figure 10'' shows a perspective view of this embodiment. Fixing part 5 is adapted for coupling to a square tube. The coupling means further comprises a vertical hinge 16V.

Figure 11 shows a "throughfeed connection". The jaw or fork tooth passes wholly through the upright and engages at multiple locations. A manual locking is provided (12, 12C), in addition to a connecting piece for a diagonal. The tube of a diagonal can move along all sides and rotate between the two half -spheres 17A and 17B which fixing part 5 comprises. Figure II ¹ shows a perspective view of the same embodiment.

Figure HA shows another embodiment of the "throughfeed connection" type. Jaw 9 passes wholly through the upright and the locking can take place by arranging a pin wholly through the upright and hole 9G in the jaw in the transverse direction. The tube of diagonal 32 can then be oriented in all directions while pivoting between the two half -spheres 17A and 17B which fixing part 5 comprises.

Figure HB shows a similar embodiment in which jaw 9 comprises a first recess 91' and a second recess 92' on its underside, these being adapted to hook over the undersides of two opposite openings in an upright. The jaw is further provided at the top with a guide means or rail 12A and a locking means or block 12 which engages on or over the rail and is connected in slidable manner thereto.

Figure HC shows an embodiment such as for instance in figure 10, without locking means 12 and vertical pivot

element 16V, and with a fixing part 5 for a rectangular tube 3 IX.

Figures 12 , 12 ' and 12 ' ' show a further embodiment of the type as shown for instance in figure 10, with a fixing means 5 adapted for coupling to a round tube.

Figures 12A and 12A' show further embodiments of coupling means which enable an orientation of the connecting element at all solid angles, comprising a swivel coupling constructed from a vertical hinge 16V and a horizontal hinge 16H.

Figure 12A' ' shows a part of a scaffold according to embodiments of the present invention, in which connecting elements of the "throughfeed connection" type are arranged. Figure 12A' ' ' is a detail view of the part A shown in figure 12A' ' . A horizontal (16H) and a vertical (16V) hinge are provided in order to enable both horizontal and vertical pivoting.

Figures 13, 13 ',13'' show embodiments as for instance described in figure 12, but provided with a horizontal hinge 16H instead of a vertical hinge 16V. Connecting part 5 is adapted here for coupling to a round tube.

Figure 14 shows a further "throughfeed connection" . The jaw or fork tooth passes wholly through the upright, after which it can drop in the upright via the recesses which are arranged in the underside of the jaw or fork tooth. A locking is hereby already obtained in the horizontal direction. In order to lock the coupling means in its entirety a manual locking 12 is also provided which passes wholly through the upright. In figure 14' the embodiment further comprises a guide means 12A for a block 12 (not

shown) . The combination with block 12 is shown in Figure 14'', and Figure 14''' shows a perspective view of this embodiment .

Figure 14A shows a coupling means 4 coupled to an upright 2 of the throughfeed connection type and analogous to those described in figures 14, 14', 14'' and 14''' . The distance d between the locking means or block 12 and the closest side of the upright (in this case,- more generally the distance between the location where the cross-section of the coupling means arranged correctly in the upright becomes greater than the cross -section of the relevant opening (so that the further sliding of the coupling means into the upright would no longer be possible here) , and the closest outer side of the upright) is however relatively smaller here than that shown in the previous figures. By choosing a greater distance d (for instance D) , as in the previous embodiment, arranging and removal of the jaw in the openings of the upright can be facilitated or become possible. The distance D is preferably greater than the thickness of the upright. The distance D is ^J preferably greater than the sum of the thickness of the upright and the width U of the part of the jaw protruding behind the upright. This is particularly a factor in the case of ledgers provided with such a coupling means on both sides. Jaw 9 comprises two recesses 91' and 92 ' , which hook into the side walls of the upright after arranging of the jaw in opening 7. After hooking- in there typically remains an opening 7 ' free between the upper side of jaw 9 and the upper side of opening 7, in which a locking means 12 can be arranged in order to thus fully block the ledger.

Figure 15 shows a further embodiment according to the present invention of the "double throughfeed connection" type. The coupling means is provided here with a first jaw

or fork tooth 9 and a second jaw or fork tooth 9 ¹ , each provided with recesses or contact surfaces 91' and 92' and an engaging surface or engaging point 92. These engaging surfaces ensure a fixation of the coupling means in the corresponding openings in the upright. In this embodiment upper jaw 9 further comprises a blocking part 92B which is situated on the outside of the upright after placing of the coupling means in the upright, and which protrudes higher than the upper edge of the opening so that the coupling means is further anchored relative to the upright.

Figure 16 shows an embodiment of the "throughfeed connection" type. Jaw 9 comprises an opening 9G and the coupling means further comprises a fixing part 5 which is provided with holes for coupling to the tube of the ledger. The jaw is adapted to pass wholly through the upright and covers substantially the whole surface area of hole 7 (a space of 0.5 mm can for instance be provided) . The locking can take place by means of a pin wholly through the upright and hole 9G in jaw 9 in the transverse direction.

Figure 16' shows a top view of this embodiment, wherein pin 18 is arranged wholly through upright 2 and through opening 9G in j aw 9.

Figure 16'' shows a side view of the same embodiment.

Figure 16A shows an embodiment of the same type as that shown in figure 16, but wherein a shorter length of jaw 9 has been chosen or, in other words, a distance d' has been chosen which is shorter than the distance D shown in figure 16'' . Through a suitable choice of the distance d as defined in figure 14 and following, for instance greater than the sum of the thickness of the upright and the width U of the part of the jaw protruding behind the upright, as explained

for figure 14 and following, removal or arranging of a ledger in the upright can be facilitated. This is particularly the case when the ledger comprises such a coupling means at both outer ends .

Figures 17 shows a further embodiment of the invention of the "double throughfeed connection" type. The jaws or foreteeth pass wholly through the upright and the jaws or fork teeth cover almost the full size of the holes. The locking can take place by means of one or more pins arranged in the transverse direction through the upright and hole 9G of one of the fork teeth. In this embodiment the jaws are preferably of substantially the same size as holes 7 (a space of 0.5 mm can for instance be provided) .

Figure 17' shows a side view, front view and cross-section in longitudinal direction of the coupling means of figure 17.

Figure 17'' shows a perspective view of the same embodiment.

Figure 17A once again shows a similar embodiment of the invention, wherein a smaller distance d is chosen between the bottom B of the (for instance angular) U- shapes defined by the two fork teeth and the closest outer side of the upright, when the coupling means is arranged correctly in the upright, than in the embodiment of for instance figure 17. The great distance D (greater than d) , which is preferably greater than the sum of the thickness of the upright and the width U of the part of the jaw protruding behind the upright, can simplify arranging or removal of the ledger in the upright. This is particularly the case when the ledger is provided with such a coupling means on both sides. Formulated more generally, the distance between the location where the cross-section of the coupling means

arranged correctly in the upright (or the jaw or fork teeth corresponding thereto) is greater than the cross -section of the relevant opening and the closest outer side of the upright is preferably greater than the thickness of the upright. This distance is preferably greater than the sum of the thickness of the upright and the width U of the part of the coupling means or the jaws which protrudes behind the upright .

Figure 18 shows a further embodiment of the present invention of the "double claw" type, wherein both claws hook and clamp shut in the upright. This double claw comprises a first claw 9 and second claw 9 ¹ , which are provided respectively with recesses 91 and 92 ^■ which are adapted to engage on respectively the bottom side of an upper opening and the top side of a lower opening in the upright, wherein these upper and lower openings are situated on the same side of the upright and are aligned along the longitudinal direction of the upright. Lower jaw 9 ¹ is fixed to the coupling means by means of a pivot 19. An automatic locking or unlocking button and control mechanism 20 are provided, for instance on the side of coupling means 4. The control mechanism is coupled to the locking mechanism of the coupling means and can preferably also be coupled to the coupling means or the corresponding coupling means at the other outer end of the ledger, for instance by means of a rod- like coupling 1OB.

Figure 18A shows a perspective view of the same embodiment.

Figures 18B and 18F show the placing of the coupling means according to the embodiment of figure 18 on an upright, wherein the control mechanism is shown in further detail. The control mechanism preferably comprises a rod 10, which runs through a longitudinal opening in connecting means 5

and is attached at its outer end directed toward the closest coupling means to an L- shaped plate which in the coupling means can block or unblock the outer end of lower jaw 9' housed therein. The plate can further comprise a sub-element for fulfilling this function. Because lower jaw 9 ¹ is mounted pivotally around a pivot 19 and the external part of jaw 9 is typically chosen to be greater than the internal part, the jaw automatically falls open when it is unblocked. In order to arrange the coupling means on the upright, the first jaw 9 is typically first inserted into a top opening

7B, then lowered slightly such that recess 91 hooks into the side of the upright on the underside of hole 7B . A space 7B' is typically also left between the upper side of jaw 9 and the upper side of opening 7. Lower jaw 9' can then be closed in pivoting manner so as to thus engage in a lower opening 7A. Following this closing engagement an automatic locking system can come into operation, based on the operation of control mechanism 20, which can comprise elements 21 and/or 10, such that the ledger becomes fixed to the upright. A space 7A' is left at the bottom, between the underside of lower jaw 9' and the upper side of opening 7A. In this embodiment no further locking is necessary due to an element optionally being arranged in one of the openings 7A' or 7B' . Note that holes 7A and 7B need not necessarily be adjacent holes, and that one or more holes can be skipped depending on the predefined distance between the holes. For a distance in the order of 3 cm it can be recommended to skip one, two or more holes in order to thus improve the strength of the coupling. In some such embodiments the use of diagonals in the scaffold can be less necessary, or unnecessary.

This operation is further shown in figure 18C. At the top the coupling means is shown when it is folded shut. In the middle view the lower jaw 9 drops open when the control mechanism releases this jaw and this jaw consequently

rotates away pivotally and opens as a result of the force of gravity. The bottom view once again shows the jaw as if it were arranged on an upright and blocked by control mechanism 20.

Figure 18D shows the same embodiment, wherein a ledger is however shown which is provided on both sides with a coupling mechanism as for instance shown in figure 18. It can be noted that this embodiment is preferably such that the upper side of the ledger, which comprises the coupling means, comprises no protrusions, and that the coupling means are preferably flat, with their surface in line with the upper surface of the tube which connects the two coupling means so as to thus form the ledger.

Figure 18E shows how the coupling means can be uncoupled from the upright in that control mechanism 20 unlocks the lower jaw, and this lower jaw is once again released and rotates out of the lower opening, herein releasing the ledger from the upright once the upper jaw or claw 9, provided with recess 91, has also been removed from the upper opening .

Figures 18B, 18F and 18G further show the control mechanism which serves for locking and unlocking of lower claw 9' . An L-shaped plate 21 which is attached to a connecting rod 10 running through an opening in connecting part 5 consists substantially of a first leg 211 which runs substantially parallel to the upper side of the housing, which in turn also runs parallel to the upper surface of the coupling means, and which is preferably connected at a right angle to a second leg 212 coupled to connecting rod 10. By now sliding the L-shaped plate forward and backward, this plate engages on the outer end of claw 9 ¹ present in the housing. Claw 9 ¹ can thus be either secured or released. When claw 9'

is released, it can drop downward. One or more sub-elements can also co-act with plate 21 in order to improve this function. A tongue 213 can further be present, which is coupled to the plate (for instance to second leg 212) and which is adapted to protrude out of an opening 22 present in the side of the coupling means, particularly in the side of the housing of the coupling means.

Figure 18H shows an embodiment of the same family, wherein a control mechanism 1OB is provided which can enable the unlocking and locking of the coupling means on the upright at both outer ends of the ledger. This can preferably take place by performing for instance a rotating movement on a shaft which is coupled to rods 10 and 10' provided in the coupling means, such that a rotation in one direction simultaneously drives the forward pushing of rods 10 and 10 ' or the retraction of rods 10 and 10 ^■ .

Figures 19A, 19B, 19C show a further embodiment of the present invention, in which coupling means 4 comprises two claws and wherein these claws are adapted to hook into the upright in two different openings on the same side of the upright. First claw 9 thus comprises a notch or recess 91 on the upper surface, while claw 9 ¹ comprises a notch or recess 91' on its lower surface. After arranging claw 9' in the lower of the two openings, wherein recess 91' hooks over the bottom edge of the lower opening, upper claw 9 can be moved upward so as to thus hook behind the top edge of the upper opening by means of notch 91. The upward movement of the upper claw can take place in different ways. It can for instance take place by providing the upper claw and the connecting body 901 associated therewith with a bore provided with screw thread. A rod provided with screw thread which can be fixed at one of its outer ends to a rotary knob 190 can then be arranged in the opening with screw thread of

body 901. Body 901 is preferably further mounted for sliding by means of a shaft-like protrusion 192 in an opening 191 present in body 901' of the lower claw. This opening 191 is preferably elongate and has a longitudinal axis which preferably runs parallel in the direction of the upright. The shaft of body 901 can then move slidably and be guided into opening 191 of lower body 901' . By tightening or loosening rotary knob 190 in the bore provided with screw thread in lower body 901' the upper claw can as a result be moved upward and downward relative to the lower claw. For the purpose of fixing the coupling means to the upright the claw 9 can thus be moved upward by tightening screw 190, while releasing the claw from the upright can take place by loosening screw 190.

Figures 2OA, 2OB and 2OC illustrate further embodiments according to the present invention, wherein the coupling means is provided with two claws 9, 9' adapted to engage in a single opening in an upright. Claws 9 and 9' are provided with respective recesses 91 and 91' which are adapted to engage on respectively the top edge and bottom edge of a single opening in the upright. Lower claw 9' can for instance be fixed to connecting part 5, while upper claw 9 can be displaceable in vertical direction. Different mechanisms can be envisaged for this purpose. In a determined embodiment the upper claw can be provided with a bore with screw thread and a rod with screw thread 193 which co-acts with a rotary knob 190 can be screwed into the opening with screw thread in the upper claw such that the upper claw can be displaced upward and downward by tightening or loosening rotary knob 190. It can be noted that this type of coupling means generally produces a less strong coupling than the coupling means which engage on at least two openings in the upright. These coupling means are therefore adapted particularly to fix scaffolding elements

which do not necessarily have to contribute toward the strength of the scaffold, such as for instance railings, although the applications are not limited thereto.

Figures 26A, 26B, 26C, 26D, 26E, 26F, 26G, 26H and 261 show a further embodiment according to the present invention. The coupling means comprises a jaw 9 constructed substantially from three parts, i.e. a first part 991, a second part 992 and a third part 993, which lie mutually in line. First part 991 and third part 993 preferably have the same cross- section, which is more preferably substantially equal to the cross-section of openings 7 in the upright, while second part 992 has a smaller cross-section than the first and the third part. The distance along the longitudinal direction of jaw 9 between the first part and the third part is preferably substantially equal to the width of a corresponding upright. When the coupling means is placed correctly in the upright, the cross-section of first part 991 and third part 993 is preferably wider than the horizontal width of the opening of the upright, such that the first and the third part provide for a locking of the coupling means relative to the upright. The second part, which has a smaller cross-section, preferably has a cross- section with a side surface which substantially corresponds to a part of the side surface of the lower portion of the holes. Second part 992 moreover preferably has a maximum diameter which is smaller than the horizontal width of the openings in the upright. This makes it possible to allow the coupling means to engage on an upright, to first rotate the upright 90 degrees around its axis relative to the final correct positioning of the coupling means in the upright, to then place the first part through the first opening on one side of the upright, to push jaw 9 further into the upright until second part 992 is also arranged in the upright, and to place the jaw further through the second opposite opening

in the upright. Once this has taken place, the coupling means can be rotated back 90 degrees around its axis such that the first and the third part 991 and 993 provide for locking of the coupling means in the direction at a right angle to the side surfaces of the upright which comprise the openings, and so that second part 992, because its surface is complementary to the bottom side of the opening, further fixes the coupling means in the sense that a rotation of the coupling means in the hole is no longer possible. This is particularly illustrated in figure 26F. This embodiment can be used for connecting elements of the railing type, but is not limited to these applications.

Figures 3OA, 3OB, 3OC show the embodiment of the "bent ledger" type, wherein two connecting elements, which are preferably of the type to be arranged horizontally in the ledger, are arranged at two successive levels in an upright (for instance levels N and N+l) , but wherein the effective height of connecting elements (for instance ledgers) is still the same and comes out at a level N+l/2. This can take place by providing body 90 with a bend, which can bridge the height difference between a level N and N+l/2 or the height difference between level N+l and N+l/2.

Figures 27A, 27B and 27C show an embodiment of the present invention which shows a pin for use in combination with uprights of the present invention. As described above, uprights according to the present invention can be placed one above the other, but also adjacently of each other and against each other. In some embodiments other connecting elements or coupling means are secured using a pin. In order to realize such connections a pin 270 can be provided which comprises an elongate main part 272 comprising a preferably solid rod, and two outer ends on either side of the main part, the first outer end comprising a screw thread 276

adapted to co-act with a corresponding nut 271 (for instance a wing nut) and the second comprising a head 273 adapted to block the pin when it has passed through the one or more uprights. In preferred embodiments head 273 comprises a means for simplifying arranging and/or removal of the pin from the upright. The head can for instance thus comprise a ring or other structure which simplifies manual removal of the pin. The pin can comprise coupling means, for instance on the head and optionally in combination with the ring or a similar structure, which are adapted to co-act with and/or engage on prior art scaffolding elements, such as for instance, but not only, cotter-head swivel couplings, swivel couplings, universal joints or welded connections. The length of the main part preferably corresponds substantially to the width of an upright or to the width of two uprights. The main part can preferably have a cross -section which substantially corresponds to the cross -section of opening 7 in the uprights. As shown in figure 27C, two uprights 2 with standard openings 7 can in this way be connected to each other by placing the upright spigot wholly through a first upright and then wholly through a second upright, and tightening nut element 271 on the first outer end of the pin provided with screw thread.

Figure 2IB shows two embodiments (R, L) of a foot jack 6 adapted for use in combination with an upright and other connecting elements according to embodiments of the present invention. A perspective view of the same embodiments is shown in Figure 21A (L + detail B, R + detail A) . Figure 21D further illustrates the embodiment R in a cross -section.

Figure 21E further illustrates the embodiment L in a cross - section. Figure 21C illustrates further embodiments.

The foot jacks serve to compensate for the level differences of the ground surface. The jacks comprise a preferably

square tube 61 coupled to a base or foot 27 by means of a pipe nut 26. The underside of tube 61 is fixed (for instance welded) to a rod Sl, which is provided with screw thread and is coupled to the top side of pipe nut 26. The base is further also coupled to a rod S2, which is also provided with screw thread and coupled to the underside of pipe nut 26. The coupling between rod S2 and foot 27 can for instance take place by means of a coupling of the ball joint type in order to enable at least partial compensation for unevenness of the ground surface. At a determined height (for instance halfway along the length of the pipe nut) pipe nut 26 comprises one or more holes 28 which are adapted for coupling to a rotating rod. The holes are preferably provided in pairs of opposite holes so that a rotating rod can be inserted wholly through pipe nut 26. Two such pairs of holes can preferably be provided, of which the axes connecting the holes of each pair are perpendicular to each other. The jack is further adapted so that no rods Sl or S2 are present at the position of the holes.

The jack can be discontinuously adjusted, for instance every 32 millimetres (or any predetermined distance between two holes lying one above the other) , by placing a pin 23 wholly through the foot jack in corresponding openings. The height of the jack can further be continuously adjusted by tightening or loosening the pipe nut, for instance using a rotating rod which couples to the pipe nut by being arranged through holes 28. The screw threads are chosen for this purpose such that, when the pipe nut is rotated in one direction, this tube 61 is pushed upward and foot 27 downward. The reverse takes place in the other direction.

The uprights can slide in (R) or around (L) tube 61.

In the embodiment L of Figures 21A,B,E the pin is provided at the bottom with a thickened portion, whereby it is easily centred in the middle of foot jack 6. Arranged on top of pin 23 is a round disc 24 which comprises a central opening and which hereby slides over the preferably square tube 61 of foot jack 6. The upright comes to lie on top of the disc and so slides over the preferably square tube 61 of foot jack 6 until it supports on ring 24. Special holes 67 can be arranged in the tube of the foot jack such that the upright can always be connected in all holes to all existing coupling means. For this purpose the holes are similar to the holes of the connecting spigot as described above for Figure 24 (7*) and can be described in similar manner.

In the embodiment R of Figures 21A,B,D foot jack 6 comprises a preferably square tube 61 with special holes 7**. Upright 2 can slide into this tube. Holes 7** are preferably centred on the holes of a corresponding upright and have a form which is chosen such that arranging coupling means according to embodiments of the present invention in the holes of the upright is not prevented. The holes are therefore preferably larger than the holes of the upright, preferably in the longitudinal direction of the upright. Lying on top of the tube of the foot jack is a special disc 24' which slides over the tube of the foot jack. This disc is provided on the top with a groove 29 adapted such that pin 23, which is placed wholly through upright 2, can centre in groove 29. An upright tongue, which makes sliding of the pin impossible, can further be provided at both outer ends of the groove. The pin is hereby also locked.

Figure 21C illustrates alternative embodiments of the types L and R. In these embodiments upright 2 can be fixed to tube 61 of the jack by means of one or more pins. A double pin 23 can for instance be used for this purpose, which comprises

two pins or fork teeth which are adapted to be arranged through the openings in an upright (and have substantially the same cross-section) . In these embodiments the holes in tube 61 can be similar to holes 7* and 7**, depending on the situation and as discussed for the foregoing embodiments, although the first, first and second and/or further openings have in each case openings of the type 7 close to the free outer end of tube 61 (in each case for each side surface of tube 61) . This makes fixing of an upright onto tube 61 possible using pins which have a cross-section corresponding to the holes of the type 7.

Embodiments of the present invention can provide at least several of the advantages stated below: • The upright has no protruding parts and thus requires a minimum of stacking space. Space-saving of 315% compared to certain competing products on the market.

• The system has no welded-on connection points so that no damage can be sustained or fouling such as mortar or plaster cannot adhere thereto.

• There are connecting or coupling options at relatively short distances, for instance every ± 30 mm. Existing systems scaffolds however have a connection every 500 mm. In practical terms this means that in the existing systems the space between the two floors is fixed at 2 metres, since 2.50 metres is too high for many activities in the building industry.

• In the existing systems uprights and diagonals must be placed when there is a change to a greater space between the floors. In embodiments of the scaffold according to the invention there is a free choice of the correct height. Ledgers, consoles, extensions etc.

can be fixed without problem to the upright at any desired height and, if desired, in four directions, this for instance every + 30 mm.

• Possibilities for reaching all solid angles around the upright owing to the claw with swivel coupling, whereby forming of bends in the scaffold becomes realizable in practice .

• Diagonals can easily be placed at level N of the scaffold in the hole above the ledger and at level N+l (typically 2 metres higher) in the hole below the ledger. Since the difference is only 30 mm, this has a negligible influence on stability and distribution of forces. Four holes thus always remain clear at level N+l for making horizontal connections.

• Easy and rapid screening of the whole using tarpaulin or shrink-wrapping, since the uprights are smooth and there are no external parts or protrusions.

• The locking does not take place using an (optionally separate) cotter. No hammer is required for assembly. Quicker working is thus possible and both hands are free, so that there is less chance of injury.

Repeatedly taking out and putting the hammer away again is moreover a time-consuming element in the erection and dismantling of the scaffold.

• The ledgers can be easily stacked (depending on the type, offset or not) , whereby a space-saving of 63% can be achieved compared to competing products on the market .

• Both claws of the ledgers can be locked by performing one operation along only one side of the ledger. The assembly time and the physical load for the erector will hereby decrease.

• The saving in space results in a substantial cost- saving compared to determined prior art scaffolds :

° Decrease in transport costs since more components can be loaded onto one truck.

_° Weight becomes more important than space. The truck no longer has to be loaded so high, this contributing toward an increased safety during loading and unloading.

_° Reduced labour costs, since fewer containers have to be loaded and unloaded.

° Smaller stacking space required at the workplace.

_° Decrease in warehouse costs : more storage in a smaller space.

• The time-saving results in a substantial cost -saving compared to determined prior art scaffolds:

o Easier and quicker stacking of the product in the transport containers .

o Smaller number of containers to load and unload as a result of the space-saving.

_° Reduction in the number of transports.

_° Rapid erection and dismantling time owing to the simple method of the product.

• Increased safety:

_° Increase in safety, since no accessories (for instance hammer) are required to assemble and disassemble the scaffold. The erector can always have the option of keeping one hand free, this resulting in increased safety.

_° In the manual displacement of the material it is much easier and safer to carry uprights without protrusions (no dishes or discs) .

o Increase in safety during the transport and during loading and unloading, since the transport containers have to be stacked much less high as a result of the space-saving.

Embodiments of the present invention moreover differ from the prior art in at least one of the following aspects:

1. Tubes (uprights, ledgers and diagonals) can preferably be square or rectangular where they are usually round in the existing systems .

2. Hook- in system of the ledgers.

3. Connecting options every 30 mm, preferably in the four directions .

4. No welded-on rosettes or extensions on the uprights.

5. No tools required for assembly.

6. Much greater stacking capacity.

While some of the embodiments described herein comprise some, but not other, properties included in other embodiments, combinations or properties 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. Properties discussed for one of the aspects of the present invention are thus typically also applicable in embodiments of the other aspects.

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.