This application is a U.S. National Stage application under 35 U.S.C. §371 of International Application PCT/NL2010/050459 (published as WO 2011/008094 A1), filed Jul. 15, 2010, which claims priority to Application NL 2003206, filed Jul. 15, 2009. Benefit of the filing date of each of these prior applications is hereby claimed. Each of these prior applications is hereby incorporated by reference in its entirety.
The invention relates to a standard for a scaffolding system, as well as a scaffolding system provided with standards and ledgers and a coupling for attaching ledgers to standards.
Different types of scaffolding systems are known. US patent publication U.S. Pat. No. 4,044,523 discloses a scaffolding system, provided with standards and ledgers. The standards are provided at regular distances with annular flanges in which cut-outs are provided. The ledgers are provided at their extremities with couplings having a slot extending in horizontal direction, in which an annular flange of a standard can be received. The coupling is further provided with a wedge which can be inserted through a cut-out into the flange and, by striking the wedge into place a coupling between a ledger and a standard can be rapidly realized. A drawback of this known scaffolding system is the presence of the annular flanges on the standards. These annular flanges complicate storage of the standards. The fact is that when the standards are stacked onto each other, the annular flanges provided at regular distances will complicate the relative sliding movement of the pipes so that taking such a standard from such a stack of standards is laborious. Furthermore, the presence of a number of annular flanges on a standard leads to a considerable increase in weight of the standard. Standards are often 2-2.5 meters long and every 500 mm an annular flange is attached to the standards. Due to the increase of the weight of the standard, the total working length of the standard is limited because with greater length, the total weight is no longer manageable for the scaffolding builder. In practice, the system disclosed in this patent is indicated as ring system.
Also known from practice is the so-called cup system. Such a cup system is described in European patent application EP-0 409 051 A2. In particular FIG. 9 of this publication clearly shows the design of this cup system. On each standard, at regular distances, two cups are provided. The lower cup is fixedly connected to the standard and the top cup is movably connected to the standard. The ledgers are provided at the extremities with flanges that can be hooked into the cups. The top cup has an upper surface that inclines upward and the standard is provided with projections designed for cooperation with the upward inclining top surface. Through rotation of the top cup, the top cup can be clamped-in in downward direction between the ledger and the projection. Thus, a ledger can be rapidly and efficiently fixed. For the cup system, in principle, the same drawbacks hold true as for the above-described ring system.
GB 1,185,169 shows, in FIGS. 9-16, different variants of standards. These known standards are provided with welded-on brackets or with bolts mounted therein on which a ledger can be placed. For these brackets and bolts the same drawbacks hold true as mentioned hereinabove.
Yet another drawback, not yet mentioned, of the known systems is that the rings, cups, brackets or bolts are always provided on the standard at quite a large distance from each other. A customary distance may be 500 mm. This distance is a compromise between weight and flexibility. From a viewpoint of flexibility, it would be advantageous to provide the rings or cups at a smaller mutual distance, so that there is a greater freedom of choice with respect to the level at which the ledgers can be connected with the standards. However, from a point of view of weight reduction, a greater distance is of advantage. Apparently, 500 mm is an acceptable compromise. Advantages of the known systems are that several ledgers can be connected at the same level to a standard and that such a connection can be realized very rapidly by a scaffolding builder. Another advantage is that the ledgers are always connected to the standards at fixed positions so that a regular framework can be obtained in a simple manner.
The object of the invention is to obviate or alleviate the above-described drawbacks.
More particularly, the object of the invention is to provide a standard of a scaffolding system which can be of relatively light design while with it, still a scaffolding system with a high degree of flexibility can be provided because the ledgers can be connected to the standards at many different levels but still at fixedly defined positions.
According to a first aspect of the invention, to this end, a standard for the purpose of a scaffolding system is provided, which standard is provided with an imaginary standard longitudinal central axis (Ls), and is further provided with:
To this end, according to a further aspect of the invention, a scaffolding system is provided, which is provided with:
According to a further aspect, the invention also provides a ledger coupling intended for such a scaffolding system, which ledger coupling is provided with:
According to a further aspect of the invention, a ledger intended for such a scaffolding system is provided, wherein the ledger is fixedly connected at at least one extremity thereof with a first side of the foot of the ledger coupling.
Since on a standard only supporting projections and, in one embodiment, optionally, orientation projections need to be provided, the standard can be of particularly light design. As the projections can be formed through plastic deformation of the tube wall, the presence of the projections does not even lead to any increase of weight. It is therefore possible to choose the distance between the successive supporting projections on the standard to be relatively small, for instance 200 mm, so that ledgers can be provided at many more desired levels than was customary up to now, while still, the ledgers maintain fixedly defined positions relative to the standards. This is highly beneficial to the flexibility of the scaffolding system. With the scaffolding system according to the invention, the objective of enhanced flexibility and weight reduction with regard to the known scaffolding systems is therefore realized, as the presence of annular flanges or cups that are connected to the standards can be completely abandoned. The standards need only be provided with supporting projections formed through plastic deformation of the tube walls and, optionally, with orientation projections. Such standards are also usable with scaffolding systems whose ledgers are not provided at their extremities with couplings, but where the ledgers are connected to the standards with the aid of separate cross connections. Cross connections are known in many types. Normally, the connection with the standard and the cross connection is realized based completely on clamping force. In order to generate sufficient clamping force, the cross connections are to be of heavy design. As a result of the presence of the supporting projections, it is no longer necessary to rely on clamping force only for vertical load on the cross connection. The fact is that owing to the supporting projections it is impossible for the cross connection to slide downwards. As a result thereof, when using standards according to the invention, the cross connections can be of much lighter design. Instead of cross connections in the order of 1 kg, with scaffolding tubes according to the invention, cross connection with a weight in the range of 200-500 g can suffice. This is highly beneficial to the comfort of the scaffolding builder. As the weight of the standards remains unchanged with respect to the conventional smooth scaffolding tubes, and the weight of the cross connections can be considerably less than with conventional scaffolding systems, the total weight of a scaffolding construction can be considerably less while the strength of the scaffolding construction remains the same. A scaffolding system with the same strength but less own weight can therefore still bear a larger effective load.
The special coupling allows a rapid connection of ledgers with standards and in one embodiment of the coupling, it is also possible that different ledgers can be connected in line with a standard as a result of the special configuration of the above-described coupling.
Other aspects and advantages of the invention will be further elucidated hereinafter on the basis of an exemplary embodiment with reference to the drawing.
The Figures show an example of an embodiment of a scaffolding tube, a ledger, a coupling and a scaffolding system according to the invention.
The standards 12 of the scaffolding system 10 each have an imaginary standard longitudinal central axis Ls. The first ledgers 14, 14′ each have an imaginary ledger longitudinal central axis L1 and two extremities 16, 16′. Each first ledger 14, 14′ is provided on at least one extremity 16, 16′ with a first ledger coupling 18, 18′. Although not necessarily, in general, each first ledger 14, 14′ will be provided on both extremities with a first ledger coupling 18, 18′. The first ledger couplings 18, 18′ are configured for connecting the extremity 16, 16′ of the first ledger 14, 14′ with a standard 12. The standard 12 is provided with supporting projections 20 which are provided, viewed in the direction of the standard longitudinal central axis Ls, at regular distances on the outside surface of the standard 12. In the present exemplary embodiment, the supporting projections 20 are each time provided diametrically opposite each other on two sides of the standard 12. With a first ledger 14, 14′ in a condition coupled to a standard 12, the first ledger coupling 18, 18′ of the respective first ledger 14, 14′ rests on a supporting projection 20.
In one embodiment, of which an example is shown in
The supporting projections 20 and the optionally present orientation projections 22 are provided in the standard through plastic deformation of the standard wall. Thus, the presence of such supporting projections 20 and orientation projections 22 does not lead to increase of weight of the standard 12. As the supporting projections 20 and, optionally, the orientation projections 22 project outside the profile of the standard only to a limited extent, the standards 12 can be removed from a stack of standards 12 in a simple manner. This is contrary to, for instance, standards of a ring scaffolding system or a cup scaffolding system. As the supporting projections 20 and the optional orientation projections 22 do not lead to weight increase of the standard 12, they can be provided at a smaller distance from each other viewed in the direction of the standard central axis Ls. This offers an improved flexibility with respect to the levels on which first ledgers 14, 14′ can be connected to the standard 12.
As already indicated hereinabove, in one embodiment, of which an example is shown in
In one embodiment, of which an example is shown in
An exemplary embodiment of the above-mentioned ledger coupling that will now be indicated with reference numeral 30 is described in the following with reference to
The coupling 30 is not only suitable for use on a first ledger 14, 14′, 38, 38′ and a second ledger 24, 24′, but is also eminently suitable for use on diagonal tubes (not shown). Diagonal tubes are always used in scaffolding systems and serve for providing the required robustness to the scaffolding. With the diagonal tubes in mounted condition, the couplings 30 that are provided on the diagonal tubes can for instance engage the first or second ledgers 14, 14′, 24, 24′.
In one embodiment, of which an example is shown in
In one exemplary embodiment, the coupling 30 can comprise a second wedge recess 66 which is provided in the coupling hook 44 adjacent the first extremity 46. The second wedge recess 66 is configured for allowing the passage of a wedge 58′ of a second, corresponding coupling 30′ of a second ledger 38′ which is connected at the same level to the standard 12. It is highly advantageous when ledgers 38, 38′ can be connected to a standard 12 at the same level, because then, floor parts that are placed on the ledgers 38, 38′ may extend at the same level. This is highly beneficial to safety.
In one embodiment, of which, again, an example is shown in the Figures, the locking element 54 can have, on a side proximal to the standard receiving space 50, a substantially circular segmental locking support surface 68. Here, an imaginary center of the circular segmental locking support surface 68 preferably substantially coincides with the central axis A of the standard receiving space 50. In the exemplary embodiment shown, the locking element is designed such that it automatically enters into the locking position when a standard 12 is pressed completely into the standard receiving space 50. By striking the wedge 58, only the securing of the locking element 54 in this locking position is realized. This effect is obtained in that the locking element 54 extends on two sides of the pivot 56, while both sides can engage on a standard 12.
In one embodiment, of which an example is shown in
In one embodiment, which is preferred from a point of view of production and rigidity and strength, the foot 32 and the coupling hook 44 are designed integrally as one single casting.
The coupling 30 described hereinabove with reference to
The invention further relates to a standard 12 which can be intended for a scaffolding system 10 as described hereinabove. As already indicated hereinabove, such a standard 12 has an imaginary standard longitudinal central axis Ls and it is further provided with supporting projections 20 which, viewed in the direction of the standard longitudinal central axis Ls, are provided at regular distances on the outside surface of the standard 12.
In one embodiment, the standard can then further comprise orientation projections 22 which, viewed in the direction of the standard longitudinal central axis Ls, are provided at regular distances on the outside surface of a standard 12 and which are each associated with an associated supporting projection 20.
As already noted hereinabove, such a standard 12 can be of light design because the projections hardly if at all add weight to the standards 12. As a result, the supporting projections 20 and the optional orientation projections 22 can be provided at a relatively limited distance viewed in the direction of the longitudinal central axis Ls of the standard 12. Thus, a great flexibility is obtained with respect to the levels on which ledgers 14, 24 can be connected to a standard 12.
Such standards 12 can also be advantageously utilized for scaffolding systems where the ledgers 14 are not provided with ledger couplings 18 at their extremities, but where the ledgers are connected to the standards by cross connections. As the cross connections can rest on the supporting projections 20, the joint between a standard and a ledger does not depend just on the clamping force the cross connection exerts on the standard 12. As a result, considerable lighter cross connections can suffice. Instead of cross connections having a weight in the order of 1 kg, cross connections with a weight in the order of 200-500 g can suffice.
Finally,
Although the invention is represented in detail and described with reference to the drawings, these drawings and the description should only be considered to serve as example. The invention is not limited to the described embodiments. For instance, in an alternative embodiment, the supporting projections 20 and the optional orientation projections 22 may also have been provided on the standards 12 through a welding operation. However, it is preferred to provide projections through plastic deformation because this does not lead to any weight increase and furthermore does not require additional finishing operations that may be required when welding because of internal stresses introduced by the welding process into the steel tubing. Other finishing operations such as, for instance, an anti-corrosion treatment, such as for instance galvanizing, can also be omitted with projections provided through plastic deformation or be carried out less intensively than when projections are provided with the aid of a welding operation. Characteristics that are described in the subclaims can be combined with each other. Reference numerals in the claims should not be construed to be limitations of the claims but serve merely as clarification.
Number | Date | Country | Kind |
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2003206 | Jul 2009 | NL | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/NL2010/050459 | 7/15/2010 | WO | 00 | 4/2/2012 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2011/008094 | 1/20/2011 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3092407 | Blonder | Jun 1963 | A |
4566819 | Johnston | Jan 1986 | A |
5427465 | Sato | Jun 1995 | A |
6168345 | Legge | Jan 2001 | B1 |
6481912 | Shih | Nov 2002 | B2 |
6575652 | Krauss | Jun 2003 | B2 |
6786302 | Liew et al. | Sep 2004 | B2 |
7147398 | Liew et al. | Dec 2006 | B2 |
7448819 | Fu | Nov 2008 | B1 |
20020106237 | Rogers | Aug 2002 | A1 |
20020141811 | Shih | Oct 2002 | A1 |
20090249591 | Melic | Oct 2009 | A1 |
Number | Date | Country |
---|---|---|
1429423 | May 1966 | FR |
2119719 | Aug 1972 | FR |
1185169 | Mar 1970 | GB |
10131475 | May 1998 | JP |
Number | Date | Country | |
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20120181111 A1 | Jul 2012 | US |