Abstract: An electromagnetic hammer having a ferromagnetic moving mass, the hammer comprising both a tube (1) designed to rest via an anvil on an element to be hammered (50), carrying a peripheral coil (2), and slidably receiving the mass (14) inside itself, and electrical power supply means connected to the coil (2) to excite it in such a manner as to generate an electromagnetic field for raising the mass, the mass striking the anvil under the action of its own weight when the coil is no longer excited, the coil (2) being made by being wound around the tube (1), and the tube being made of a non-magnetic material and having means (3, 4, 5, 6) for taking up axial forces and for transmitting said forces to the anvil (13) while the mass (14) is being raised. The power supply means comprise an flywheel associated with a rotary motor and with an alternator.

Abstract: A method and device are provided for simultaneously driving two driving wheels of a vehicle by means of a driving roller meshing with both wheels. This roller is formed of star-shaped flanges carrying bars which engage the sculptures of the tires, so as to push out the dirt collected on the tires. This dirt is easily evacuated between the arms of the roller flanges. The invention applies to the drive of any tandem set of wheels, including those of tracked vehicles and heavy vehicles.