Extended pins according to this document are used in roller chains according to DIN 8188-1 for assembling of further elements. These chains are used mainly for conveyor purposes.
DIN 8188-3:1998 history
2012DIN ISO 606:2012 Short-pitch transmission precision roller and bush chains, attachments and associated chain sprockets (ISO 606:2004)
1998DIN 8188-3:1998 Roller chains - American type - Part 3: Simple roller chains with extended pins; connecting dimensions