DIN EN 74-1:2005 pdf free.Couplers, spigot pins and baseplates for use in falsework and scaffolds -Part 1: Couplers for tubes – Requirements and test procedures.
6 General requirements
6.1 Materials
All elements of couplers shall be made of steel or cast iron and shall fulfil the requirements given in European Standards where design data are provided. Some information about those most commonly used is given in
EN 12811-2. Elements shall be protected against atmospheric corrosion in general in accordance with EN 12811-2. Electrolytical zinc coating C1 with an average thickness of 15 jim conforms to 8.1 of 12811-2:2004.
For screw and nut connection, other corrosion protection which is specified in EN or ISO standards may be applied. It shall be shown that they achieve at least equivalent protection. When tested to EN 10002-1, cast irons shall have a minimum elongation of 5 % on ultimate strength where 3d.
6.2 Design
6.2.1 A coupler model of a defined type and class shall conform to all requirements specified in Table 8. It means for any structural parameter that the evaluated test results shall be equal or exceed the specified values in this European Standard except for indentation. The characteristic values and safety coefficients to be applied for use shall be as given in EN 12811-1 and in EN 12812.
6.2.2 The design of couplers shall be such that after tightening onto any steel or aluminium tube given in Clause 5 and tightened in accordance with 7.1.7 and 7.1.8, there shall be significant effective travel on the nut or wedge.NOTE Experience shows that 2 mm of thread or wedge remaining and a minimum gap of 2 mm between the closing flap and the body are suitable limits.
6.2.3 A coupler shall be manufactured so that the elements cannot be separated during normal service condition. The bolt class shall be at least M12. The bolt strength class shall be at least grade 5.6 in accordance with EN ISO 898-1. The proof load on each bolt, R shall not be less than 32,2 kN and the R.I.JRM ratio not greater than 0,8. The recommended bolt is M14x2, with tolerances in accordance with ISO 965. 114Whft’wor.th threads shall comply with Annex A. The nut and bolt combination shall be in accordance with EN 20898-2. The nut shall be one of the following: — plain hexagonal nut with a separate loose washer; or special flanged hexagonal nut having an integral fixed washer flange; or — special hexagonal nut incorporating an integral rotating washer. The outside diameter of the washers or nut flanges shall be at least equal to the measurement across the corners of the hexagonal nuts at specified dimensions + 2 mm. The washer or nut flange thickness shall not be less than 2,5 mm. A loose washer shall have a hardness of between 200 HV and 300 HV.DIN EN 74-1 pdf download.