Abstract: The present invention mainly relates to a shock absorbing apparatus for travelling a table or tool rest in machine tools such as a grinding machine, a lathe, a milling machine, a planer, and a drilling machine, wherein staged notch section is formed at both a feed nut travelling in engagement with a feed screw shaft of a table or a tool rest and an engaging bracket placed below said table or said tool rest or a bushing member fixed together with said engaging bracket a sliding collar having a notched section in order to engage with said corresponding notch section is located between said feed nut and said engaging bracket or said bushing member, one end of said sliding collar is formed as to be projected from the outer extreme end of the same side of said feed nut in order to make it possible that a spring receiver is mounted, thereby causing a hollow section to be formed between said sliding collar itself and the extreme end of said feed nut at the same side, and the other end of said sliding collar is so fo

Abstract: By mounting unusual vibration transducer apparatus consisting of a piezo-electric vibration detecting member, a pre-amplifier including a gain adjust knob, a comparator including level adjust knob, a monostable multivibrator including a pulse width adjust knob, a preset counter including preset value setting switch, a flip flop memorizing signals, an amplifier amplifying signals, and an output circuit at a machine tool like a grinding machine, a lathe, a milling machine, a planer, and/or a drilling machine, or by mounting only a piezo-electric vibration detecting member and installing the other components at a separate position outside a specified machine tool, vibrations produced during machining work are taken out by a comparator as high or low signal and alarm is then issued when such a vibration reaches the preset value of the counter, causing rotation or travel of a tool to stop or feed of workpiece to stop, and/or causing the rapid infeed rate of wheelhead to be changed to an adequate roughing feedrate.