A padlock is a block of metal pierced by a keyhole, with a pivoted or hinged link to secure doors and such. It’s a period charge: a padlock Or was one of the badges of Francis, Viscount Lovel, d.1487 [HB 123]. For related charges, see fetterlock, shackle.
Randwulf Witlac bears: Sable, a padlock and on a chief argent, three wolves’ heads couped sable.
Saerthryth Seolforlocc bears: Per fess engrailed argent and azure, a padlock argent.
Rónán Ó Gobhann bears: Gules, a padlock and a chief argent.