This standard specifies the characteristics of long pitch precision roller chains used for mechanical power transmission and for conveyors and the characteristics of the corresponding attachments and wheels. It provides the dimensions, tolerances and minimum measurement and breaking loads. These long pitch chains derive from some short pitch precision transmission chains covered by UNI 7484, with which they have common dimensions except for the pitch which is twice as large. These chains are intended for uses with less severe conditions, in relation to the speed and power transmitted, compared to the chains referred to in UNI 7484 from which they derive.
UNI 7890-1978 history
1978UNI 7890-1978 Extended pitch precision roller chains, attachments and chain wheels for transmission and conveyors.