US Patent 11919134 Working tool

A tool having a working piston that moves along a working axis, a drive, for driving the working piston along the working axis, the drive having an electrical capacitor, a squirrel-cage rotor arranged on the working piston and an excitation coil, wherein current flows through the coil during rapid discharge of the capacitor and generates a magnetic field that accelerates the working piston, the tool having a frame of a soft-magnetic and electrically conducting material surrounding the excitation coil and extending in a circumferential direction with respect to the working axis, the frame having one or more at least partial interruptions, which extend over a significant part of a radial extent of the frame with respect to the working axis.