Coat of arms of Blacknell

The blazon

per bend or ( another, ar.) and az. an eagle, displayed, counterchanged. — Crest, an arm, embowed, vested, gu. cuff ar. holding in the hand ppr. four feathers, per pale, ar. and gu.

A blazon is the description of a coat of arms in the technical language of heraldry. The drawing comes from that text, and from nothing else.