Improvements in acoustic vibration apparatus, signal emitters (Machine-translation by Google Translate, not legally binding)

摘要

Improvements in signal-emitting acoustic vibration apparatuses, characterized by having a casing, preferably made of cast iron, which in the upper part consists of a threaded cylinder threaded by its external surface, hollow in its interior, provided with a fixing nut which cooperates in its adaptation to said casing, whose cylinder constitutes an air intake duct, which narrows in its terminal, after a bend that suffers in its trajectory, empties into a chamber of membranes. (Machine-translation by Google Translate, not legally binding)