Abstract: The non-impact dot matrix printer is a high speed alpha-numeric, electric spark discharge printer that utilizes a rotating perforated dielectric belt in cooperative association with a laminar stack of insulated electrical conductors to control electric spark discharge printing on an electrical conductive erosive surface of a recording medium. The belt is disposed between the laminar stack and the conductive surface of the recording medium, and alpha-numeric characters are printed on the printing surface by applying a controlled source of voltage between the printing surface and the stack to cause spark discharging through the perforations in the rotatable belt, under the overall control of appropriate electronic circuitry.

Abstract: An impact sensing detector for monitoring the operation of metal forming impact presses. The detector operates on an analog electric signal corresponding to the shock wave produced as the press ram impacts the fixed press platen and workpiece to produce a plurality of samples of the amplitude of said analog signal. These samples are digitized and compared against time corresponding standard samples previously derived from normal press operation. The detector may also be applied to other working areas of the press where waveform analysis can detect improper operation in order to avoid catastrophic failures. Predetermined differences between compared samples produce warning indicator signals which may be used to stop the press and also a fault analysis tool to help the press operator pinpoint the malfunction.