Analysis of vibration transmission in an air-operated demolition hammer

The paper presents an analysis of vibrations of a ram, body and handle of a heavy, air-operated demolition hammer. The research was conducted in order to determine the character of dynamic inputs and resulting vibrations at the tool handle which were necessary to build a structural model of local influences on an operator taking the hammer design into account. The experiment was carried out on a test stand without participation of an operator, which guaranteed repeatability of measurements and elimination of ontogenetic characteristics. The displacements of selected structural elements of the tool were recorded by means of a camera and the accelerations at the handle were recorded by means of a standard measuring apparatus. The recorded signals were subjected to the spectral analysis and the short-time Fourier transform (STFT) using dedicated software in MATLAB environment.