Striking device for dot printer

Striking system comprising at least one set formed of groups of several striking devices, each striking device comprising an electrodynamic coil lying generally in a plane and operatively associated with a striking hammer, said coil including two parallel rectilinear parts, magnetic means producing a first magnetic field acting on said first rectilinear part and practically perpendicular to the plane of said coil and said first rectilinear part, second magnetic means producing a second magnetic field acting on said second rectilinear part with the direction of said second magnetic field being opposite to the direction of said first magnetic field, a deformable elastic suspension unit connecting said coil to a fixed support, said electrodynamic coil being a spiral in the form of a thin metal foil having at least one spiral cut therein, and said elastic suspension unit including narrow strips which are substantially coplanar with each other and with said spiral, said striking devices being juxtaposed side by side in a group with said groups being mounted onto a common axle and separated by the magnetic means which produce said magnetic fields, and means for separately introducing electrical energy into each of said coils.

A striking unit comprising a fixed axle, an elastic suspension unit fixedly mounted on said axle, an electrodynamic coil mounted on said suspension unit for pivoting relative to said fixed axis, said coil being in the form of a thin metal foil sheet having at least one spiral cut therein and defining at least one spiral strip including two parallel rectilinear parts, a striker hammer carried by said coil for movement therewith, first magnetic means disposed adjacent said coil remote from said axle for producing a first magnetic field substantially perpendicular to the plane of said foil sheet and to said first rectilinear part, second magnetic means producing a second magnetic field acting on said second rectilinear part with the direction of said second magnetic field being opposite to the direction of said first magnetic field, and means connected to said coil for selectively electrically connecting said coil to a source of electrical energy to effect a pivoting of said coil and said hammer about said axis.