Standard and ledger of a scaffolding system, and method for erecting the same

Abstract

A standard (10) of a scaffolding system (1), comprising an elongate tubular wall (12), having a central longitudinal axis (L.sub.s), and at least one supporting projection (14) that protrudes radially outwardly from said tubular wall (12). When the standard (10) is in a vertical orientation, the supporting projection (14), seen in a tangential direction (T.sub.s) relative to the longitudinal axis (L.sub.s), forms an annular supporting surface (16) that encircles the tubular wall (12) and that defines alternating elevations (18) and depressions (20). Also disclosed is a ledger (30) with ledger couplings (40) configured for cooperation with said standard (10).

Claims

1. A standard of a scaffolding system, comprising: an elongate tubular wall, having a central longitudinal axis; a plurality of substantially identical supporting projections that are regularly spaced apart along the longitudinal axis of the standard and that protrude radially outwardly from said tubular wall, wherein each supporting projection is a plastic deformation in the tubular wall and defines an annular supporting surface that is an integral part of the tubular wall and encircles the tubular wall and that, seen in a tangential direction relative to the longitudinal axis, when the standard is in a vertical orientation, defines alternating elevations and depressions, and wherein each of the elevations or depressions of the supporting surface of the supporting projection is associated with a keeper projection that is a plastic deformation in the tubular wall and that is an integral part of the tubular wall.

2. The standard according to claim 1, wherein the alternating elevations and depressions of the annular supporting surface define a periodic waveform.

3. The standard according to claim 2, wherein the periodic waveform is a generally sinusoidal or triangular waveform.

4. The standard according to claim 2, wherein the supporting surface defines a generally square waveform.

5. The standard according to claim 2, wherein the elevation-to-depression amplitude of the waveform is at least 0.5 cm.

6. The standard according to claim 2, wherein the distance between two consecutive elevations, as seen in the tangential direction with respect to the longitudinal axis of the standard, is at least 3 cm.

7. The standard according to claim 1, wherein each of the keeper projections is located axially above the respective associated elevation or depression when the standard is in a vertical use orientation.

8. The standard according to claim 1, wherein the supporting surface defines at least two depressions.

9. The standard according to claim 1, wherein two depressions of said alternating elevations and depressions of the supporting surface of the supporting projection are mutually offset in the tangential direction by n.Math.90 degrees, n being a positive integer in the range of 1-3.

10. The standard according to claim 8, wherein the supporting surface defines four depressions.

11. Scaffolding system, comprising: at least one standard according to claim 1; and at least one ledger comprising: an elongate tubular wall, having a central longitudinal axis; at least one ledger coupling, connected to the elongate tubular wall at an extremity thereof; characterized in that the ledger coupling includes a foot that is configured to be supported on the supporting surface of a supporting projection of said at least one standard, and that has a contour complementary to an elevation or depression of the supporting surface, such that the foot may be at least partially fittingly received on or in said elevation or depression, respectively.

12. The scaffolding system according to claim 11, wherein the foot of the ledger coupling includes a keeper projection recess, which is configured to fittingly receive a keeper projection associated with said elevation or depression of said supporting surface of said supporting projection of said at least one standard when the foot is at least partially fittingly received on or in said elevation or depression, respectively.

13. Scaffolding system, comprising at least one standard including: an elongate tubular wall, having a central longitudinal axis; a plurality of substantially identical supporting projections that are regularly spaced apart along the longitudinal axis of the standard and that protrude radially outwardly from said tubular wall, wherein each supporting projection is a plastic deformation in the tubular wall and defines an annular supporting surface that is an integral part of the tubular wall and encircles the tubular wall and that, seen in a tangential direction relative to the longitudinal axis, when the standard is in a vertical orientation, defines alternating elevations and depressions; and at least one ledger comprising: an elongate tubular wall, having a central longitudinal axis; at least one ledger coupling, connected to the elongate tubular wall at an extremity thereof; characterized in that the ledger coupling includes a foot that is configured to be supported on the supporting surface of a supporting projection of the plurality of supporting projections, and wherein the foot has a contour complementary to an elevation or depression of the supporting surface, such that the foot may be at least partially fittingly received on or in said elevation or depression, respectively.

14. Method for erecting a scaffolding frame, including: providing a scaffolding system according to claim 11 or claim 13; arranging the standard in a substantially vertical orientation; and supporting the ledger coupling of the ledger on the supporting surface of the at least one supporting projection of the standard, thereby allowing gravity to slide the contour of the foot into fitting engagement with an elevation or depression of said supporting surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic perspective view of a node of a first exemplary embodiment of a scaffolding system, wherein the standard has multiple axially spaced apart supporting projections each defining a supporting surface with a generally sinusoidal waveform;

(2) FIG. 2 is a schematic perspective view of a node of a second exemplary embodiment of a scaffolding system, wherein the standard has multiple supporting projections each defining a supporting surface with a generally square waveform;

(3) FIG. 3 is a schematic perspective view of an exemplary embodiment of a ledger extremity fitted with a ledger coupling suitable for use with the supporting projections of the standard shown in FIG. 1;

(4) FIG. 4 is a schematic cross-sectional perspective view of the exemplary embodiment of the ledger extremity shown in FIG. 3;

(5) FIG. 5 is a schematic top view of the exemplary embodiment of the ledger extremity shown in FIG. 3;

(6) FIG. 6 is a schematic cross-sectional top view of the exemplary embodiment of the ledger extremity shown in FIG. 3;

(7) FIG. 7 is a schematic perspective view of two ledgers extremities as shown in FIGS. 3-6 in aligned engagement with each other;

(8) FIG. 8 is a schematic cross-sectional perspective view of the ledger assembly shown in FIG. 7;

(9) FIG. 9 is a schematic perspective view of a second exemplary embodiment of a ledger extremity fitted with a ledger coupling suitable for use with the supporting projections of the standard shown in FIG. 2; and

(10) FIG. 10 is a schematic perspective view of a node including a standard with two aligned ledgers and one transverse ledger, and having floor parts arranged on the latter.

DETAILED DESCRIPTION

(11) FIG. 1 is a schematic perspective view of a node 2 of a first exemplary embodiment of a scaffolding system 1. The node 2 comprises a standard 10, two aligned ledgers 30, and a transverse ledger 30. It is understood that a node 2 may alternatively be formed by a standard 10 and one first ledger 30, by a standard 10 and two first ledgers 30, by a standard 10 with a first ledger 10 and two second ledgers 30, or a standard with two first ledgers 30 and two second ledgers 30.

(12) The standard 10 of the scaffolding system 1, which extends along an imaginary central longitudinal axis L.sub.s, includes an elongate tubular wall 12. In the depicted embodiment the tubular wall 12 is substantially cylindrical; it is contemplated, however, that alternative embodiments of the standard 10 may have a non-circular cross-sectional shape, for instance a regular polygonal shape. The standard 10, including the tubular wall 12, may be manufactured from metal, e.g. steel, sheet steel, or aluminum, or another suitable material.

(13) The standard 10 may include one or more supporting projections 14, which may protrude from an external surface of the tubular wall 12, in a generally radially outward direction R.sub.s with respect to the central longitudinal axis L.sub.s. In the depicted embodiment, the standard 10 includes multiple supporting projections 14 which are regularly spaced apart along the length of the standard, e.g. at regular distances of about 250 mm or 500 mm.

(14) Each of the supporting projections 14 may extend circumferentially around the tubular wall 12 of the standard 10. When the standard 10 is in a vertical use orientation, an upper surface of each of the supporting projections 14 may define an annular supporting surface 16. Seen in a tangential direction T.sub.s relative to the central longitudinal axis L.sub.s, this supporting surface may define alternating elevations 18 and depressions 20. Or phrased otherwise, the axial/vertical coordinate of the supporting surface 16 of a supporting projection 14 may vary in the tangential direction T.sub.s.

(15) In the embodiment of the standard 10 depicted in FIG. 1, each of the supporting projections 14 takes the form of a wavy ring that, as it extends along the circumference of the tubular wall 12, defines a supporting surface 16 which undulates according to a generally sinusoidal or triangular waveform. It is understood that, when embodied in metal, for example in the form of an upset flange, the ideally varying slopes of sinusoidal wave flanks may approximate the straight flanks of a triangular wave, while the ideally angular elevations/depressions of a triangular wave may approximate the arched elevations/depressions of a sinusoidal wave, such that these types of waveform may in practice appear quite similar. The terms generally sinusoidal and generally triangular are therefore to be construed as referring also to imperfect sinusoidal or triangular waveforms.

(16) The periodic length of the waveform of the supporting surface 16 depicted in FIG. 1 is equal to about .sup.th of the circumference of the tubular wall 12, such that four substantially sinusoidal or triangular waves fit onto this circumference. Accordingly, the supporting surface 16 alternatingly defines four elevations 18 and four depressions 20. In alternative embodiments, the waveform of the supporting surface 16 may have a different periodic length, for example half of the circumference of the tubular wall 12. The different supporting projections 14 are arranged such that the elevations 18 and depressions 20 of their supporting surfaces 16 are in axial registry with each other. This facilitates the erection of a regular scaffold frame, and ensures that ledgers 30, 30 connected to the standard 10 at different axial positions radiate from the standard in the same respective directions.

(17) A supporting projection 14 having a sinusoidal or triangular waveform as shown in FIG. 1 offers the advantage that it may gently guide an extremity of a ledger 30 supported thereon towards the nearest depression 20, irrespective of the point on the supporting surface 16 on which the extremity is first supported. A drawback of the sinusoidal and triangular waveforms, however, is that their sloping flanks may allow a firm horizontal push against a (not yet secured) ledger 30 that is still being connected to the standard 10 to force the ledger from the depression 20 in which it is trapped. This is in particular true when the amplitude of the waveforms is relatively shallow. The problem may be overcome by using a supporting surface 16 defining steeper flanks, such as a substantially square waveform, instead.

(18) FIG. 2 schematically illustrates a second exemplary embodiment of a node 2 of a scaffolding system 1. In this embodiment, the standard 10 is provided with multiple supporting projections 14 each defining a supporting surface 16 with a generally square waveform, again with a periodic length equal to about .sup.th of the circumference of the tubular wall. The flanks 22 of the supporting surface 16 run parallel to the longitudinal axis L.sub.s of the standard and are sufficiently steep (relative to the horizontal) to prevent an extremity 34 of a ledger 30 trapped in a depression from being pushed out by a horizontal thrust.

(19) The supporting projections 14 may preferably be provided on the standard 10 through plastic deformation of its tubular wall 12. Alternatively, a supporting projection 14 may be manufactured separately, and subsequently be slid onto and then connected, e.g. welded, to the tubular wall of the standard. This latter option, however, is more laborious and thus more costly.

(20) In an embodiment, of which an example is shown in FIG. 1, each of the depressions 20 of a supporting projection 14 may be associated with a, typically stud-like, keeper projection 24. Like the supporting projection 14, the keeper projection 24 may preferably be formed by plastic deformation of the tubular wall 12 of the standard 10. Alternatively, it may be manufactured separately and later be connected, e.g. welded, to the outside of the tubular wall 12. When the standard 10 is in a vertical orientation, the keeper projection 24 may be located axially above the respective associated depression 20.

(21) The keeper projection 24 is particularly useful in combination with a supporting projection 14 that defines a supporting surface 16 with gently sloping flanks 22 and relatively shallow depressions 20. Although such a supporting surface 16 presents an important improvement over the prior art in its ability to aid in selecting a nearby ledger mounting position (in the form of a depression), and in trapping the ledger extremity 34 at such a position, the rough treatment of a ledger 30 that is sometimes required to force it into place between two standards 10 may exceed the level of release-resistance that the supporting projection 14 is dimensioned to provide. Thus, in such cases, a yet unlocked and freely supported ledger extremity 34 may occasionally be pushed out of contact with the supporting projection 14.

(22) This problem may be overcome by, on the one hand, associating a keeper projection 14 with each of the depressions 20 of a supporting projection 14, and, on the other hand, providing ledger couplings 40 (connected at ledger extremities 34) with a complementary provision in the form of a keeper projection recess or slot 78. Accordingly, when the ledger 30 is loosely coupled to the standard (e.g. supported on the supporting projection 14 of the standard 10, but not yet secured thereto) the keeper projection 14 may be received in the keeper projection recess 78 in order to define the rotational and/or translational position of the ledger coupling 40 relative to the standard 10.

(23) The construction of a ledger 30, and of a ledger coupling 40 that is provided at an extremity thereof, will now be clarified below with reference to FIG. 3-8.

(24) A ledger 30 may comprise an elongate tubular wall 32, having a central longitudinal axis L.sub.l and two opposite extremities 34. At least one of the extremities 34 may be provided with a ledger coupling 40 that is configured to connect the ledger extremity 34 to a standard 10. For clarity it is noted that in the embodiments of FIGS. 1 and 2, the ledger couplings 40 are designed such that two ledgers 30 can be connected in mutual engagement to a standard 10 at a same axial/vertical level, such that the central axes L.sub.l of the ledgers 30 are in line with each other (see also FIG. 7).

(25) A ledger coupling 40 may comprise a foot 42, which may have a first side 44 that is (configured to be) fixedly connected to an extremity 34 of a ledger 30 associated with the coupling 40. To this end the first side 44 may define a foot ring 50. The foot 42 may further comprise two foot wings 52 lying opposite each other. Each foot wing 52 may be provided, on a side remote from the foot ring 50, with a foot support surface 48. The foot support surface 48, which thus lies at a second side 46 of the foot 42, opposite the first side 44, serves for abutment against an outside surface of the standard 10. With such a design, the first end 56 of a coupling hook 54 (to be described below) may be connected to both the foot ring 50 and the two foot wings 52. Between the two foot wings 52, a hook receiving space may be formed inside the foot 42, which space may provide a receiving possibility for a coupling hook 54 of a second, corresponding coupling 40 of a second ledger 30 that is to be connected to the standard 10 at the same level.

(26) An important aspect of the foot 42 of the coupling 40 depicted in FIGS. 3-8 is the outer contour 49 of each of its wings 52, in particular near the second side 46 of the foot 42. It is understood that the foot 42 may be configured to be supported on the supporting surface 16 of a supporting projection 14 of a standard 10 as shown in FIG. 1. More in particular, the foot 42 may be configured to enable sliding off of elevations 18 of the supporting surface 16, along the flanks 22 thereof, towards a state of stable reception in a flanked depression 20 of the supporting surface 16. To this end, a foot wing 52 of the coupling 40 may have a contour 49 complementary to a flanked depression 20 of the supporting surface 16, such that at least a part of the foot 42 may be fittingly received in said flanked depression 20, and preferably such thatin a fully received statethe contour 49 only contacts the flanks 22 while remaining clear of the depression 20 itself. Smooth, generally convex contour shapes are preferred to facilitate movement of the foot 42 towards and into a depression 20.

(27) In the embodiment of the coupling 40 shown in FIGS. 3-8, the contour 49 of a foot wing 52 includes two opposite, convexly tapering sides for engagement with the flanks 22 of a depression 20, and a convex, slightly flattened apex designed to remain clear of the depression 20 itself. By way of example, FIG. 9 shows an alternative embodiment of a ledger coupling 40 that is configured for cooperation with the supporting projections 14 on the standard 10 shown in FIG. 2. The contour 49 of the foot wing 52 shown in FIG. 9 includes two straight, parallel sides for engagement with the flanks 22 of a square depression 20 of the supporting surface 16 shown in FIG. 2, and a straight tip for contact with the depression 20 itself.

(28) A coupling 40 may further comprise a coupling hook 54, which may be connected at a first end 56 to the foot 42. The coupling hook 54 may form a coupling hook support surface 60 which, together with the foot support surface 48, may define a substantially semi-circular standard receiving surface 48, 60. The radius of the standard receiving surface 48, 60 may substantially correspond to an outer diameter of a standard 10. The substantially semi-circular standard receiving surface 48, 60 may define a standard receiving space 62 having a central axis A which, with the coupling 40 in a condition coupled to a standard 10, may substantially coincide with the central axis of the standard L.sub.s. Together with the foot 42, the coupling hook 54 may define a standard inlet 64 via which a standard 10 can be introduced into the standard receiving space 62.

(29) The coupling 40 may further comprise a locking element 66 which may be hingedly connected to the coupling hook 54 about a pivot 68. The pivot 68 may extend parallel to the central axis A of the standard receiving space 62. The locking element 66 may have a locking position in which the standard inlet 64 is blocked by the locking element 66. The locking element 66 may further have a releasing position in which the standard inlet 62 is released for letting a standard 10 into or taking it out of the standard receiving space 62. The locking element 66 may have, on a side proximal to the standard receiving space 62, a substantially circular segmental locking support surface 76. An imaginary center of the circular segmental locking support surface 76 may coincide with the central axis A of the standard receiving space 62. In the embodiment of FIGS. 3-8, the locking element 66 is designed such that it automatically enters into the locking position when a standard 10 is pressed completely into the standard receiving space 62. This effect is obtained in that the locking element 66 extends on two sides of the pivot 68, while both sides can engage on a standard 10.

(30) The coupling 40 may also comprise a wedge 70, which may be slideably connected to the coupling hook 54, and which, in a securing position, may engage the locking element 66 and hold this locking element 66 in the locking position. In an alternative embodiment of the coupling 40, the wedge 70 may be replaced by a bolt (not shown), which may be screwingly (instead of slideably, as with the wedge) inserted into a threaded recess in the coupling hook 54 in order to engage the locking element 66 and hold it in its locking position.

(31) The coupling 40 may additionally comprise a first wedge recess 72 in the coupling hook 54 adjacent the second end 58 of the coupling hook 54 that is remote from the first extremity 56 of the coupling hook 54 connected to the foot 42. The wedge 70 may be slideably but not removably received in the wedge recess 72. Such a design has as an advantage that when erecting a scaffolding frame, the wedge 70 cannot come loose from the coupling 40, so that it is always at hand. Furthermore, the wedge 70 falling on a bystander or a fellow scaffolding builder is thus prevented. Moreover, striking the wedge 70 into place allows a rapid, secure connection of a ledger 30 to a standard 10. The uncoupling of a ledger 30 can be realized rapidly too by knocking the wedge 70 loose.

(32) The coupling 40 may further comprise a second wedge recess 74, which may be provided in the coupling hook 54 adjacent the first extremity 46. The second wedge recess 74 may be configured to enable the passage of a wedge 70 of a second, corresponding coupling 40 of a second ledger 30 which is connected at the same level to the standard 10. It is highly advantageous that ledgers 30 can be connected to a standard 10 at a same axial/vertical level, because then, floor parts 4 that are placed on the ledgers 30 may extend at the same level. This is highly beneficial to safety.

(33) In one embodiment, which is preferred from a point of view of production and rigidity and strength, the foot 42 and the coupling hook 54 may be designed integrally as one single casting.

(34) Finally, FIG. 10 shows a node of a scaffold frame, including two longitudinally aligned ledgers 30 and one transversely arranged ledger 30, all of which are connected to a standard 10. The depicted coupling 40 of the transverse ledger 30 rests on the couplings 40 of the two longitudinally aligned ledgers 30, which are in mutual engagement at the same vertical level. The two couplings 40 themselves are supported on the supporting surface 16 of a supporting projection 14 of the standard 10, such that their feet 42 are stably arranged in opposite depressions thereof. On the second ledger 30, floor parts 4 are placed.

(35) Although illustrative embodiments of the present invention have been described above, in part with reference to the accompanying drawings, it is to be understood that the invention is not limited to these embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, it is noted that particular features, structures, or characteristics of one or more embodiments may be combined in any suitable manner to form new, not explicitly described embodiments.

LIST OF ELEMENTS

(36) 1 scaffolding system 2 node 4 floor part 10 standard 12 tubular wall of standard/standard tube 14 supporting projection 16 supporting surface 18 elevation/gravitational potential hill 20 depression/gravitational potential valley 22 flank 24 keeper projection 30 ledger 32 tubular wall of ledger/ledger tube 34 extremity of ledger 40 ledger coupling 42 foot 44 first side of foot 46 second side of foot 48 foot support surface 49 contour of foot support surface 50 foot ring 52 foot wing 54 coupling hook 56 first end of coupling hook 58 second end of coupling hook 60 coupling hook support surface 62 standard receiving space 64 standard inlet 66 locking element 68 pivot 70 wedge 72 first wedge recess in coupling hook 74 second wedge recess in coupling hook 76 locking support surface 78 keeper projection recess A central axis of standard receiving space L.sub.s longitudinal central axis of standard L.sub.l longitudinal central axis of ledger R.sub.s radial direction with respect to longitudinal axis of standard T.sub.s tangential direction with respect to longitudinal axis of standard