IEC 60120:2020 pdf download

IEC 60120:2020 pdf download.Ball and socket couplings of string insulator units – Dimensions
1 Scope
The object of this international standard is to define the dimensions of a series of standard ball and socket couplings using the standard locking devices (see IEC 60372) in order to permit the assembly of insulators or metal fittings supplied by different manufacturers. This document applies to string insulator units of the cap and pin and long rod types and their associated metal fittings. For the pin ball and the socket, dimensions apply to the finished product after any surface treatment. Extreme positions of the pin ball in the socket are given in Annex A. Typical examples of gauges for checking the dimensions of pin balls and sockets are given in Annex B. NOTE Only the dimensions necessary for assembly are dealt with in this standard. Properties of material and working loads are not specified. The co-ordination of dimensions with strength classes is specified in IEC 60305 and IEC 60433.
3 Terms and definitions
For the purposes of this document, the terms and definitions of IEC 60050-471, some of which are reproduced below for ease of reference, apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses:  IEC Electropedia: available at http://www.electropedia.org/ ISO Online browsing platform: available at http://www.iso.org/obp 3.1 ball and socket coupling coupling consisting of a ball, a socket and a locking device, and providing flexibility [SOURCE: IEC 60050-471:2007, 471-03-11]3.2 string insulator unit cap and pin insulator or long rod insulator of which end fitting are suitable for flexible attachment to other similar insulator units or to connecting accessories [SOURCE: IEC 60050-471:2007, 471-03-08]
4 Designated size of coupling
This document includes eight standard ball and socket couplings designated by the nominal pin diameters in millimetres. Each designated size of coupling is defined by the dimensions of the pin ball, of the socket, of the hook-on “GO” gauge, of the lower part of the insulator and of the corresponding locking device. NOTE Dimensions of twin-balled pins for coupling of two sockets are stated in Clause 13. Dimensions of the hole for the locking devices are stated in Clause 14 and Clause 15.
5 Pin ball
The pin ball shall conform to the dimensions specified in Clause 10. The main dimensions governing the shape of the pin ball are h , d , r and r . Dimension r is given for guidance 1 2 1 2 3 because its accurate value may be obtained only by the drawing. In addition, the shank diameter d , must not exceed the specified values within a length equal to H 3 of the 1 corresponding worn hook-on “GO” gauge (see Clause 12).
6 Socket
The socket interior shall conform to the dimensions specified in Clause 11, which also specifies the thickness of the locking device. The 16 mm designated size of coupling according to Clause 11 includes two alternative sockets. There is only one type of pin ball fit for it, but the corresponding locking device should be used. That is, the 16A socket should be matched with the 16A locking device, the 16B socket should be matched with the 16B locking device. NOTE Sockets according to the clause mentioned are shown with flat bottoms. Sockets with rounded bottoms with radii of curvature not less than the dimensions r 2 of the pin balls can also be used. In this case, the dimensions R 5 have to be correspondingly decreased.