WO1988003212A1

WO1988003212A1 - Scaffolding system

Info

Publication number: WO1988003212A1
Application number: PCT/AU1987/000346
Authority: WO
Inventors: Hans Heinrich Schmidt
Original assignee: Lubeca Contruction Systems Pty. Ltd.
Priority date: 1986-10-28
Filing date: 1987-10-14
Publication date: 1988-05-05

Abstract

A connecting element (20) for use between a ledger or transom (12), and a standard (11), in a scaffolding system, and including a hook shaped member (19) attached to the end of the ledger or transom, with a slot (21) being provided between the hook shaped member and the remainder of said connecting element and which receives a connecting eyelet (18) attached to the standard. A spring biased retractable pin (22, 25) is carried by the connecting element and is movable across the entrance to the slot and beneath the eyelet to prevent unintentional disengagement of the hook shaped member from said eyelet. The leading end of the retractable pin is tapered at (27) whereby, during connection to the eyelet, the engagement of the tapered end with the eyelet forces the pin to move to its retracted position against the action of the biasing spring (25) and whereby, after the engagement has passed, the pin extends back into the slot beneath the eyelet under the action of the biasing spring. The hook shaped member is tapered and at least part of the inside of the eyelet is similarly tapered to produce a wedging action.

Description

SCAFFOLDING SYSTEM Technical Field

This invention relates to a scaffolding system and more particularly heavy duty scaffolding for the construction industry as well as scaffolding producing heavy duty formwork support systems and also lightweight mobile scaffolding.

Background Art

The scaffolding systems to which the present invention relates basically consist of standards in the form of upright members which in turn support horizontal ledgers for spacing the standards and horizontal transoms which apart from spacing the standards also support working platforms 88/03212 - ₂ -

formed from timber and metal planks. The system is completed by braces extending diagonally between vertically and horizontally spaced corners, formed by connections between the standards and the ledgers and transoms, and such as to render the system rigid and square. In addition, such systems include stage brackets for support of the scaffold planks, and tie bars which hook onto the stage brackets to assist in correct spacing of the scaffold planks, and also together with ladder access and return transoms, toe board clips for fixing of kick board planks to the standards, screw jacks to allow leveling of the system and head screw jacks which allow height adjustment of overhead beams and the like.

The aforementioned components form the basic components of scaffolding and formwork support systems to which the present invention relates, whilst a relatively large number of special purpose fittings can also be provided for special systems.

The present invention relates particularly to the connection of ledges, transoms and bracers to the standards. With known systems there have been provided lower fixed upright cup-shaped supports on, and surrounding, a standard with upper loose inverted cup shaped connectors surrounding the standard. The ends of the ledgers and transoms are provided with diametrically opposed lugs, a lower one of which jams within the lower support in the annular space between it and the standard, and the upper one of which is jammed between the upper connector in the annular space between it and the standard when the upper connector is moved downwardly and whereby rotation of the upper connector about the standard and subsequent striking of protruding lugs thereon tightly locks the ends of all the ledgers and transoms into position on the standard at the connector. One such system is marketed in Australia under the name Cuplok by S.G.B.. Other known systems include the use of fixed, upright, cup-shaped supports on the standards and into the annular space between it and the standard is received a down

turned or otherwise attached hook member on the end of an associated ledger, transom or brace, with the hook member being jammed against the support by means of a wedge-shaped member received through an aperture in the end of the associated ledger, transom or brace, and against the outer frame of the support. Such a system has been marketed under the name Betco Scaffolding by Betco Manufacturing Company. A similar system, utilizing wedges, is also marketed under the name Wedgelock by Waco International Limited, except that the support, rather than being cup-shaped, consists of a plurality of U-shaped loops forming eyelets with the free ends being welded to the standard to provide recesses into which the hook members on the ends of the ledgers, transoms or bracers, are received. The major problem with such known systems is the reliance on a wedging or jamming action between the ends of the ledgers, transoms or bracers, and the supports and connecting parts which, due to incorrect or non-diligent assembly, can result in loose connections or connections which eventually work loose, whilst with some of such systems the requirement for separate loose components for the connections means possible lose or theft of components and inconvenience during installation if dropped. Considerable effort can also be required during disassembly in order to unlock the wedged or jammed components.

Disclosure of the Invention

The present invention therefore envisages a connecting element for use between a ledger, transom or brace, and a standard, in a scaffolding system, said connecting element including a hook shaped member attached to, or adapted in use to be attached to, the end of a ledger, transom or brace, with a slot being provided between said hook shaped member and the remainder of said connecting element and adapted, in use, to receive a connecting eyelet attached to said standard, and retractable means supported by said connecting element and movable across an entrance to said slot to a position extending beneath said eyelet to prevent unintentional disengagement of said hook shaped member from said eyelet.

Preferably said retractable means cooperates with means to bias it towards said extended position.

Preferably said biasing means is a spring means.

Preferably said retractable means has a finger engaging portion formed thereon by which to retract it from extended position against the action of said biasing means. Preferably the leading end of said retractable means is tapered whereby, during assembly, its engagement with said eyelet forces it to move to said retracted position against the action of said biasing means and whereby, after the engagement between said retractable means and said eyelet has past, said leading end extends back into said slot.

Preferably the hook member is tapered and at least part of the inside of said eyelet is similarly tapered whereby said hook member will be wedged within said eyelet, but is such that said wedging action can be broken when required by upwardly forcing or striking said hook member and/or said connecting element.

Best Mode for Carrying out the Invention

One preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a side elevational view of a scaffolding system having connections incorporating connecting elements in accordance with the present invention;

Figure 2 is a cross-sectional view through the standard taken along lines 2-2 of Figure 1?

Figure 3 is an enlarged side elevational view, partially sectioned, of the connector of Figure 1;

Figure 4 is a perspective view of a standard and an affixed connecting member with which the connecting element engages; and Figure 5 is a perspective view of the connecting element of Figure 3.

Referring to Figure 1 of the drawings a typical scaffolding system incorporating the connections of the present invention is generally illustrated as 10, and comprises upright standards 11 of hollow tube, with ledgers or transoms 12 also of hollow tube and interconnecting spaced apart standards. As shown, the upper ends of the standards have extension members 13 of reduced diameter received within the standards and fixed thereto, and which in turn are slidably received in the ends of further standards 11 and pinned thereto through aligned holes 14 and 15 to extend the height of the scaffolding system.

Connecting members 16 surrounding the standards are fixed thereto, such as by welding at 16a, and are provided at spaced apart intervals along the length of the standard. With reference to Figures 2, 3 and 4 of the drawings, each connecting member 16 comprises a sleeve 17 surrounding and fixed to the tube of the standard, with a plurality, in this case four, U-shaped straps forming eyelets 18 attached to, such as by welding, at their free ends to the sleeve 17, and within which hook like members 19 forming part of connecting elements 20 will be received as will be later described. The connecting elements 20 are in turn received and fixed within, such as by welding at 20a, the ends of the tubes forming the ledgers or transoms 12.

Turning to Figures 3 and 5 of the drawings, each connecting element 20 comprises a hook like member 19 forming a slot 21 between itself and the remainder of the connecting element, whilst the other end of the connecting element has a cylindrical section formed thereon which is received within the end of the associated ledger or transom 12. The connecting element 20 carries a retractable pin or bolt 22, which is slidably received within the connecting element such as to be moved between a retracted position and an extended position across the slot 21 as shown in Figures 3 and 5, whereby, when the hook like member is received within the eyelet 18, the strap forming the eyelet is caught within the slot and the retractable pin or bolt 22 will prevent upward movement of the connecting element and disengagement of the hook like member from within the eyelet. The pin or bolt within the connecting element has an abutment 23 formed thereon and, together with the remainder of the pin or bolt and the upper portion of the inside of the connecting element, defines a chamber 24 within which a compression coil spring 25 is received. One end of the coil spring 25 bears against the abutment 23 and the other end against a downwardly extending portion 23a of the connecting element and serves to bias the retractable pin or bolt to a position across the entrance to the slot 21. The lower edge of the pin or bolt 22 has a finger grip 26 formed therein so as to enable, in trigger like fashion, the pin or bolt 22 to be retracted, against the biasing action of the spring 25, from the slot 21 and allows the connecting element and its hook like member to be disengaged from the eyelet.

The leading end of the pin or bolt 22 is provided with a tapered surface 27, whereby, upon connection of the connecting element to an eyelet, the contact of the strap of the eyelet with the end of the pin or bolt forces the pin or bolt to move to its retracted position against the biasing action of the spring 25, and, after the pin and strap have passed each other, the spring returns the pin to its extended position closing the slot and the horizontal upper surface of the end of the pin adjacent the strap acts as a stop during attempts to disengage the connecting element from the eyelet and prevents disengagement unless the pin is retracted. In addition, the vertical surface of the sleeve at the eyelet is downwardly and outwardly tapered at 28, and its cooperation with a similar taper on the hook-like member 19 produces a wedging action to also counteract disengagement of the hook member and the eyelet, and such wedging action can be counteracted merely by applying an upward force or striking action to the hook-like member and/or connecting element and/or end of the ledger, transom or brace with which the connecting element is associated.

The components of the connection, including the sleeve and straps forming the eyelets, the hook like member and the remainder of the connecting element, may be formed from sturdy, hammer forged steel, and when applied to a lightweight scaffolding system, such as a mobile system, the sleeve and eyelet component may be fetted to aluminium tubing forming the standards with aluminium tubing also being used for the ledgers, transoms and braces.

It is to be understood that the invention includes any modifications that would be envisaged by a person skilled in the art and which do not depart from the spirit of the invention, and any such modifications are to be considered within the scope of the invention.

Claims

88/03212 - 8 -CLAIMS :

1. A connecting element for use between a ledger, transom or brace, and a standard,- in a scaffolding system, said connecting element including a hook shaped member attached to, or adapted in use to be attached to, the end of a ledger,- transom or brace, with a slot being provided between said hook shaped member and the remainder of said connecting element and adapted, in use, to receive a connecting eyelet attached to said standard, and retractable means supported by said connecting element and movable across an entrance to said slot to a position extending beneath said eyelet to prevent unintentional disengagement of said hook shaped member from said eyelet.

2. A connecting element as claimed in Claim 1, wherein means are provided to bias said retractable means towards its extended position across the entrance to said slot.

3. A connecting element as claimed in Claim 2, wherein said biasing means is a spring.

4. A connecting element as claimed in Claim 2 or 3, wherein said retractable means has a finger engaging portion formed thereon by which to retract it from said extended position against the action of said biasing means.

5. A connecting element as claimed in any one of Claims 2 to 4, wherein the leading end of the retractable means is tapered whereby, during connection to said eyelet, the engagement of said tapered end with the eyelet forces said retractable means to move to said retracted position against the action of said biasing means and whereby, after the engagement of said tapered end and said eyelet has passed, said leading end extends back into said slot beneath each said eyelet under the action of said biasing means.

6. A connecting element as claimed in any one of the preceding claims, wherein said hook shaped member is tapered and at least part of the inside of said eyelet is similarly tapered whereby said hook member will be wedged within said eyelet.

7. A connecting element for a scaffolding system, substantially as hereinbefore described with reference to the accompanying drawings.

8. A scaffolding system including at least one connecting element as claimed in any one of Claims 1 to 7.

£