GB2149046A - Scaffolding structure - Google Patents

Abstract

A scaffolding joint (1) comprises an interconnected standard (3), a ledger (4) and a brace (5) which, when assembled to form a multi-component scaffold structure, have their respective longitudinal centre of gravity lines (4G, 5G) (gravity lines) in a common vertical plane, and boltless means, eg wedge (11) and latches (16, 17), readily connecting and disconnecting the respective end fittings of the ledgers (4), standards (3) and braces (5) are provided. <IMAGE>

Description

SPECIFICATION Scaffolding structure This invention relates to a scaffolding structure, particularly for constructing a shoring structure, but equally applicable for constructing an access structure.

In recent times, conventional scaffold structures in which the required structure size and shape was constructed from a plurality of tubular poles with loose fittings, including screw tightening members, to make joints at required locations e.g. between adjacent pole ends, has been replaced by systems incorporating captive fittings avoiding screw members. Apart from increasing the speed by which joints may be made and struck by the scaffold erector, captive fitting systems firstly ensure that fittings cannot be lost, and secondly are of enhanced life in that by avoiding screw threaded members, then bending or other damage to the screw threaded members, or rusting of those members, with attendant delays in the making and striking of structures, is avoided.In detail, scaffold structures with captive fittings are constructed from standards (upright members) provided with a plurality of external sockets spaced apart both circumferentially and longitudinally of the standard, a selected socket being adapted to receive a knock-in, knock-out fastening wedge captively received in an end fitting of a ledger (horizontal member). Such end fittings have also incorporated upper and lower circular, through holes to receive a pin projecting laterally to one side of a brace (diagonal member) which, in use, is located diagonally with respect to the standards and ledgers, the use of braces triangulating the rectangular frameworks constructed with standards and ledgers and thereby increasing the rigidity of the scaffold structure.Another commonly used means of connecting braces within a scaffold structure has been with attachments on the sides of standards, of either pin or socket type, to marry with brace-end fittings.

Furthermore, in prior art proposals, the points of intersection of the longitudinal axes or gravity lines of braces, standards and ledgers have neither coincided nor been in close proximity. Thus when a scaffold using such members has been loaded, secondary stresses have been created due to either or both forms of eccentricity caused by the configuration of such members.

According to the present invention, there is provided a multi-component, linear element scaffolding structure comprising interconnected standards, ledgers and braces which when assembled to form the structure, stand with the longitudinal centre of gravity lines (gravity lines) of the joined standards, ledgers and braces in common vertical planes along and across the structures, together with boltless means of connecting and disconnecting the end fittings of the ledgers to standards and end fittings of the braces to end fittings of the ledgers providing rigid standard to ledger joints capable of withstanding bending moments equal to or greater than the moments of resistance of the standards and ledgers so joined, without (or with negligible) angular rotation one member away from the other, and hinged ledger-end to brace-end joints to transmit forces between diagonally opposite standard to ledger to brace joints in an assembled scaffold bay of two lengths of parallel, spaced apart standards and two parallel, spaced apart ledgers, axially or substantially axially through the connecting brace.

The structures in accordance with the invention, by ensuring that the braces are not offset with respect to the vertical plane in which the associated standards and ledgers are located, and that the longitudinal axes or gravity lines of braces, standards and ledgers meet or nearly meet at a point in a nodal joint, results in an improved system due to the elimination or near elimination of secondary stresses, so that the structure in accordance with the invention is capable of accommodating increased loads in comparison with prior art structures embodying off-set braces and/or substantially non-coincidental intersections of the longitudinal axes or gravity lines of the structural members.

Preferably, the gravity lines of the ledgers and braces intersect within the transverse dimension of the connecting standard, passing through the outsides of associated sockets, adapted to carry a ledger-end, provided on the standard within the common plane of standard, ledger and brace, at a nodal standard-toledger-to-brace joint.It is also preferred for each ledger end fitting to be formed by means of spaced apart upper and lower limbs to fit respectively above and below a selected socket on the standard and held in position thereon by a wedge passing through slots in both upper and lower limbs of the ledger-end fittings and inside the socket, so that when the wedge is driven home the upper and lower limbs abut the adjacent periphery of the standard in, or substantially in, the common vertical plane of standard and ledger so joined together, and with an additional slotted arm above the upper limb of the ledger-end fitting, forming part of said fitting, and spaced from the adjacent periphery of the standard, the slot of the arm being smaller than, or equal in width to the slots in the upper and lower limbs, so as to retain the wedge within the ledger-end fitting when the wedge is in its raised position, by preventing a thickened or deformed portion at the lower end of the wedge, which portion is capable of passing through the slots of the lower and upper limbs, from passing through the said slot in the said additional arm and also conveniently to restrain the wedge in the raised position canted away from the standard with the bottom edge of the wedge resting on a top surface of the upper limb of the ledger-end fitting.It is also preferred that each ledger-end fitting comprises brace retaining latches, and housings to accommodate brace-end loadbearing pins insertable from one or either side of the ledger-end fittings, the latches being pivotally mounted and resiliently biassed so as to open automatically upon insertion of the brace-end pins into the selected ledger-end housings and to close automatically when the brace-end pins have been pushed into their correct load-bearing positions, with the latches capable of being opened by hand, against their resilient bias, to permit brace removal.

Preferably, the brace-end pins and the ledger end housings to receive same are both cylindrically shaped centrally to ensure axial loading of the ledger-end and brace, as structural loading of the brace is developed, and the brace-end pins at their ends remote from their supporting arms thereof and both sides of the ledger-end pin housings all are frusto-conical in shape to permit insertion and removal of the brace-end pins with ease and also during insertion of the brace-end pins to ensure that the scaffolding bays triangulated by the braces are brought to correct rectangular shape.The structure may further comprise base jacks, head jacks and associated braces, all adjustable in length, with the base jacks and head jacks being respectively for mounting coaxially below and on top of standards and being provided with integral brace-end retaining latches and housings to accommodate brace-end pins, together with braces adjustable in length with end load-bearing pins of part cylindrical and part frusto-conical shape for fixing between base-jacks and the lowest ledger-end pin housings connected to adjacent standards and from head-jacks down to the top ledger-end pin housings connected to an adjacent standard, with said adjustable braces gravity lines in the same vertical planes as the gravity lines of the standards at their ends and the ledgers and braces above them and below them respectively.

Conveniently, the standards, ledgers, and braces, are all tubular although members of other cross-sections could be used.

In detail, the joints between the braces and ledger-end fittings are preferably of a quick action push-in, push-out type, and being boltless, they avoid the use of screw threaded tightening members and attendant disadvantages.

The resilient loading of the latching means may be effected by one or more springs, rubber blocks etc., or by torsional spring means incorporated in the pivot. Such a latching means enables a pin to be inserted into a selected aperture from either end of the aperture and hence from either side of the end fitting, while furthermore places no constraints on alternative angular positions that the braces may wish to occupy in differing locations.For instance, it may be required that the diagonal angle of braces with respect to adjacent ledgers in the vertical plane may vary between approximately 22' and 704 to suit differing ledger lengths and vertical distances between ledgers one above the other and also between approximately 22' and 70 to suit differing ledger lengths and differing vertical distances between ledgers and brace attachment positions on base and head jacks respectively at the lower and upper ends of standards.

The invention will now be further described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a portion of a scaffolding structure in accordance with the invention; Figure 2 is a section on the line ll-ll of Fig.

1; Figure 3 is a section on the line Ill-Ill of Fig. 1; Figure 4 is a plan view of Fig. 1, with the brace omitted; Figure 5 is a section on the line V-V of Fig.

4; and Figure 6 is a section on the line VI-VI of Fig. 4.

In the drawings, and in particular in Fig. 1, is illustrated a portion of a multi-component, linear element, scaffolding structure 1 in accordance with the invention, the portion being a joint 2 between an elongate, upright standard 3, an elongate, horizontal ledger 4 and an elongate, diagonally located brace 5, the scaffolding structure 1 being constructed with a plurality of spaced apart standards 1, an adjacent pair defining a bay, with the ledgers 4 approximating in length to the width of each bay, and with the braces 5 extending diagonally across the bay, between a ledger 4 and either an upper and/or a lower ledger, at the other side of the bay, or a head jack or a base jack, provided respectively at the terminal upper end and lower end of each standard 3. Hence each standard 3 has a vertical longitudinal axis or gravity line 3G, each ledger has a horizontal longitudinal axis or gravity line 4G, and each brace has a diagonal longitudinal axis or gravity line 5G.

As can be seen from Fig. 1, the standards 3, ledgers 4 and braces 5 are of hollow, tubular section, the standard 3 being provided at selected spacings, both longitudinally and circumferentially with V-shaped sockets 6, one socket only being illustrated in Fig. 1 and Fig.

4, while the head jacks and base jacks (not shown) usually associated with the respective upper and lower ends of the standard 3 may be of generally conventional design, but incorporating housings and latches for brace-end connection and retention.

To each ledger 4 is welded, at each end, an end fitting 7 comprising an upper limb 8 and a lower limb 9 spaced apart from one another to define a gap 10 capable of accommodating a selected socket 6, each limb 8 and 9 being slotted so that a locking wedge 11 is readily slidable between the limbs, with the wedge 11 illustrated in full line in Fig. 1"in its locked position, and illustrated in chain dotted line in Fig. 1 in its raised and unlocked position.

Above the upper limb 8 is provided an arm 12, which is also slotted but to an extent smaller than that of the limbs 8 and 9, such that a projection 1 1A at the lower end of the wedge 11 can pass through the slots in the limb 8 and 9, but cannot pass through the slot in the arm 1 2. The end fitting 7 is also provided with a pair of housings in the form of through holes 13, each hole comprising a frusto-conical outer portion 14 and a cylindrical inner portion 1 5 the centres of which lie on the gravity lines 5G.Furthermore each end fitting is also provided, adjacent each hole 1 3 with an aperture 1 6 housing a pair of or a single brace retaining latch 1 7 pivotally mounted on a pin 1 8 for rotation about an axis 1 9 and each latch loaded by a spring 20 into its latching position (illustrated in Fig. 2) and manually displaceable from its latching position, and having a latching head 21 with a retaining face 22, and an angled displacement face 23.

To the end of each brace 4 is welded an end fitting 24 comprising a support spigot 25, an integral supporting arm 26 projecting longitudinally from one side of the support spigot 25 and having a chamfered face 27, a rear face 28 and an integral, load-bearing pin 29 extending orthogonally with respect to the gravity line 5G and having a frusto-conical lead in nose 30 and a contiguous cylindrical portion 31 which lies on the gravity line 5G and is adapted, in the assembled condition, to engage the cylindrical inner portion 1 5 of a selected hole 1 3.

To assemble a ledger to a standard, a socket 6 is selected, and with the wedge 11 in its retracted position, the limbs 8 and 9 are engaged around the selected socket and the wedge 11 then lowered through the slot in the upper limb 8, the socket 6, and the slot in the lower limb 9 for hammering home to tighten the joint 2, thereby part forming a joint 2, so that the standard gravity line 3G and the ledger gravity line 4G lie in a common, vertical plane P, as shown in Fig. 4. To connect a brace 5, in order to complete formation of the joint 2, a pin 29 at one end of a brace 5 is pushed into a selected hole 1 3 in a ledger end fitting 7.Initially, the chamfered face 27 of the supporting arm 26 strikes the angled displacement face 23 of the latch 17, to rotate the latch 1 7 about its pivot axis 19, to enable the pin 29 to penetrate its selected hole, the chamfered lead-in nose 30 of the pin 29 serving to centre progressively the pin 29 in its hole 1 3 and simultaneously to pull the structure into true, right angled triangular shape, or considering a complete bay, into true rectangular shape, the latch 1 7 automatically rotating to its latching position illustrated in Fig. 2 in which its retaining face 22 engages behind the rear face 28 of the brace-end fitting 24, to prevent inadvertant withdrawal of the pin 29 from its hole 1 3.

Intentional withdrawal is effected by thumb pressure on the latching head 21, until the latch 1 7 has been rotated to an extent that the retaining face 22 clears the rear face 28 of brace-end fitting 24. Thus, in the assembled and latched condition best illustrated in Fig. 2, the cylindrical portion 31 of the pin 29 engages the cylindrical inner portion 1 5 of the hole 13, and because the pin 29 extends orthogonally and has its cylindrical portion 31 intersected by gravity line 5G, the latter also finds itself within the common vertical plane P, thereby substantially if not wholly eliminating from the structure secondary stresses present in prior art constructions which employ off-set braces.

As shown in Fig. 1, the gravity line 5G from brace 5 intersects the gravity line 4G from ledger 4 at an angle of 46" and at a location within the lateral dimension i.e. of the standard 1 between the outward extremitites, of the sockets, the gravity line 5G passing through the upper, outer side of the socket 6, while a gravity line 5G from a lower brace (not shown) which is also connected to the end fitting 7, also intersects at 46 within the lateral dimension of the standard at a common point 32.

Claims (6)

1. A multi-component, linear element scaffolding structure comprising inter-connected standards, ledgers and braces which when assembled to form the structure, stand with the longitudinal centre of gravity lines (gravity lines) of the joined standards, ledgers and braces in common vertical planes along and across the structures, together with boltless means of readily connecting and disconnecting the end fittings of the ledgers to standards and end fittings of the braces to end fittings of the ledgers providing rigid standard-to- ledger joints capable of withstanding bending moments equal to or greater than the moments of resistance of the standards and ledgers so joined, without (or with negligible) angular rotation one member away from the other, and hinged ledger-end to brace-end joints to transmit forces between diagonally opposite standard-to-ledger-to-brace joints in an assembled scaffold bay of two lengths of parallel, spaced apart standards and two parallel, spaced apart ledgers, axially or substantially axially through the connecting brace.

2. A scaffolding structure as claimed in Claim 1, wherein the gravity lines of the ledgers and braces intersect within the transverse dimension of the connecting standard, passing through the outsides of associated sockets which are, adapted to carry a ledger-end and are, provided on the standard within the common plane of the standard.

ledger and brace, at a nodal standard-toledger-to-brace joint.

3. A scaffolding structure according to Claim 1 or Claim 2, wherein the ledger-end fittings are each formed by means of spaced apart upper and lower limbs to fit respectively above and below a selected socket on the standard and held in position thereon by a wedge passing through slots in both upper and lower limbs of the ledger-end fittings and inside the socket so that when the wedge is driven home the upper and lower limbs abut the adjacent periphery of the standard in, or substantially in, the common vertical plane of standard and ledger so joined together, and with an additional slotted arm above the upper limb of the ledger-end fitting, forming part of said fitting, and spaced from the adjacent periphery of the standard, the slot of the arm being smaller than, or equal to in width the slots in the upper and lower limbs, so as to retain the wedge within the ledger-end fitting when the wedge is in its raised position, by preventing a thickened or deformed portion at the lower end of the wedge, which portion is capable of passing through the slots of the lower and upper limbs, from passing through the said slot in the said additional arm and also conveniently to restrain the wedge in the raised position canted away from the standard with the bottom edge of the wedge resting on a top surface of the upper limb of the ledger end fitting.

4. A scaffolding structure as claimed in any preceding Claim, wherein each ledger end fitting comprises brace retaining latches and housings to accommodate brace end loadbearing pins insertable from one or either side of the ledger-end fittings, the latches being pivotally mounted and resiliently biassed so as to open automatically upon insertion of the brace-end pins into the selected ledger-end housings and to close automatically when the brace-end pins have been pushed into their correct load-bearing positions, with the latches capable of being opened by hand, against their resilient bias, to permit brace removal.

5. A scaffolding structure as claimed in Claim 4, wherein the brace-end pins and the ledger-end housings to receive same are both cylindrically shaped centrally, to ensure axial loading of the ledger-end and brace, as structural loading of the brace is developed, and the brace-end pins at their ends remote from their supporting arms thereof and both sides of the ledger-end pin housings are all frustoconical in shape to permit insertion and removal of the brace-end pins with ease and also during insertion of the brace-end pins to ensure that the scaffolding bays triangulated by the braces are brought to correct rectangular shape.

6. A scaffolding structure as claimed in Claim 4, wherein the angle of inclination of the brace is such that intersection of the gravity lines of the brace and ledger at a nodel joint is within the transverse dimension of a socket of the standard.

6. A scaffolding structure as claimed in any preceding Claim, comprising base jacks, head jacks and associated braces, all adjustable in length, with the base jacks and head jacks being respectively for mounting co-axially below and on top of standards and being provided with integral brace-end retaining latches and housings to accommodate brace end pins, together with braces adjustable in length with end load-bearing pins of part cylindrical and part frusto-conical shape for fixing between base-jacks and the lowest ledger-end pin housings connected to adjacent standards and from head-jacks down to the top ledger-end pin housings connected to an adjacent standard, with said adjustable braces gravity lines in the same vertical planes at the gravity lines of the standards at their ends and the ledgers and braces above them and below them respectively.

7. A scaffolding structure as claimed in any preceding Claim, wherein the standards, ledgers, and braces, are all tubular.

8. A scaffolding structure as claimed in any preceding Claim, wherein the joints between the braces and ledger-end fittings are of a quick action push-in, push-out type.

9. A scaffolding structure as claimed in any preceding Claim, wherein the resilient loading of the latching means is effected by one or more springs, rubber blocks etc., or by torsional spring means incorporated in the pivot.

1 0. A scaffolding structure substantially as hereinbefore described with reference to the accompanying drawings.

CLAIMS Amendments to the claims have been filed, and have the following effect: Claims 1 and 2 above have been deleted or textually amended.

New or textually amended claims have been filed as follows: Claims 3 to 10 above have been re-numbered as 7 to 14 and their appendancies corrected.

1. A multi component, linear element scaffolding structure comprising interconnected standards, ledgers and braces, with the longitudinal centre of gravity lines (gravity lines) of joined standards, ledgers and braces in common vertical planes along and across the structure and furthermore with the gravity lines of interconnected braces and ledgers intersecting within the overall transverse dimension of interconnecting standards, together with boltless means of readily connecting and disconnecting end fittings of the ledgers to connection elements of the standards and boltless means of readily connecting and disconnecting end fittings of the braces to the end fittings of the ledgers.

2. A scaffolding structure as claimed in Claim 1, wherein the standards, which when joined end to end have the same longitudinal axis, comprise an elongate tubular element and a plurality of external connection elements spaced apart longitudinally, the ledgers each comprise an elongate element and end fittings providing both rigid standard-to-ledger joints capable of withstanding bending moments equal to or greater than the moments of resistance of the standards and ledgers so joined without (or with negligible) angular rotation one member away from the other, and hinged brace-to-ledger joints to transmit forces between diagonally opposite standardto-ledger-to-brace joints in an assembled bay of two lengths of parallel, spaced apart standards and two parallel, spaced apart ledgers, axially or substantially axially, through the connecting brace.

3. A scaffolding structure as claimed in Claim 2 wherein the connection elements on the standards are sockets, with groups of sockets comprising two pairs of sockets at right angles to each other and each pair diametrically opposite each other across the longitudinal tubular elements.

4. A scaffolding structure as claimed in Claim 3, wherein the gravity lines of the ledgers pass centrally, or generally so, through the sockets on the standards to which they are connected, and the gravity line of a brace, inclined to associated ledgers at an angle dependant upon the chosen horizontal distance between the two standards and the chosen vertical distance between the ledgers of an assembled scaffold bay, intersects the ledger gravity lines within the overall transverse dimension of the two standards at the nodel standard-to-ledger-to-brace joints.

5. A scaffolding structure as claimed in Claim 4, wherein the angle of inclination of the brace is such that intersection of the gravity lines of the brace and ledgers at a nodel joint is within the transverse dimension of the tubular element of the standard.