Abstract: A multiple bore electromagnetic projectile launcher is provided with series circuit elements connected to the muzzle end of conductive rails of a bore to continue current conduction in those rails following the launch of a projectile and during the launch of a successive projectile. This current flow augments the flux in the successive bore during the launching of a successive projectile. Individual firing switches can be provided for each bore or additional conductive rails can be provided in an automatic switching arrangement to conduct current from a muzzle of a fired bore to the breech of a successive bore.

Abstract: An electromagnetic projectile launching system utilizes two cylindrical rail configurations. In one configuration, multiple conductive armatures are electromagnetically accelerated along rails which are located on the inner surface of a cylindrical barrel. The second configuration utilizes armatures located between concentric cylindrical rails. Rifling provides for spin stabilization of the projectile.

Abstract: The conductivity of the laminations in an armature which conducts current between the launcher rails or switch rails of an electromagnetic propulsion system is graded such that uniform current density is achieved in each lamination. The conductivity of each lamination, which increases from the breech end to the muzzle end of the armature, is related to that of the lamination at the breech end by a single proportionality factor which is a function of the length of the armature in the direction of armature travel, the half-width of the gap between the rails, the velocity of the armature, the magnetic permeability of the rails, and the conductivity of the breech laminations and of the rails.

Abstract: A folding boom construction comprising a wheeled frame, a boom disposed transversely of the wheeled frame, the boom being adapted to support one or more cultivating tools, the boom being coupled to the wheeled frame to be rotatable about a substantially transverse axis of the wheeled frame, the boom being rotatable about an axis transverse of the boom such that on rotation about the axis transverse to the wheeled frame the cultivating tools can be raised or lowered from the ground and when the tools are in the raised position the transverse axis is substantially upright such that the boom can be swung from the transverse position to a fore-and-aft position.