Apparatus for determining levels of physical loads

An apparatus for determining levels of physical loads, having a housing with two switching elements disposed therein and electrically coupled to an indicator and through a cut-out switch to a power supply unit. The apparatus further comprises a seismic mass constituted by a permanent magnet and secured in the housing by means of elastic suspension elements. The switching elements are positioned along the direction of movement of the seismic mass. The indicator includes three indicating elements indicating, respectively, the minimum, the optimum and the maximum level of physical load. One of the switching elements is a group of magnetically operated hermetically sealed changeover contacts, while the other switching element is a pair of magnetically operated hermetically sealed normally open contacts, said group of changeover contacts including a normally open contact connected to one of the terminals of the indicator element indicating the minimum level of physical load, a normally closed contact connected to one of the terminals of the indicator element indicating the optimum level of physical load, and a common contact connected to one of the terminals of the power supply unit and to one of the contacts of said pair of contacts the other contact of which is connected to one of the terminals of the indicator element indicating the maximum level of physical load. The other terminals of the indicating elements of the indicator through the cut-out switch are connected to the other terminal of the power supply unit. The seismic mass is positioned in the zone of operation of said group of changeover contacts.