Battering Ram

large hard tool used to beat in a locked door or wall

A battering ram is a chase engine originating in ancient times to break open fortification walls or doors.In its simplest form, a battering ram is just a large, heavy log carried by several people and propelled with force against an obstacle; the momentum of the ram would be sufficient to damage the target if the log were massive enough and/or it were moved quickly enough (i.e., had sufficient velocity).
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Noun
1. a ram used to break down doors of fortified buildings
(hypernym) ram

(n.)
An engine used in ancient times to beat down the walls of besieged places.
  

(n.)
A blacksmith's hammer, suspended, and worked horizontally.
  

See Bosson .