FIELD: mine hoisting plants equipped with two hoisting vehicles. SUBSTANCE: device has two waveguides located hoisting shaft parallel to direction of motion of hoisting vehicles. Located in upper part of hoisting shaft are transmitters and receivers of oscillations of electromagnetic waves. Transmitters and receivers are designed for transmission of electromagnetic waves by waveguides and reception of waves after their reflection from moving hoisting vehicles. Included between transmitters are receivers of electromagnetic wave oscillations are circulators for uncoupling of transmitted and received electromagnetic waves. Connected to end of each waveguide is matched load. Outputs of oscillation receivers are inputs of data processing unit which is made of successively connected mixers, filters, amplifiers, discriminators and single-threshold comparator. Th latter is connected so that signals from branch of one hoisting vehicle are always input, and signals of branch of other hoisting vehicle are always reference with respect to which input signals are compared. Comparator output serves as output of data processing unit electrically connected with safety brake of hoisting plant drive. In this case, frequency of electromagnetic waves reflected from moving hoisting vehicles differs from frequency of transmitted electromagnetic waves from oscillation transmitters by a value of Doppler frequency proportional to speed of motion of hoisting vehicle in hoisting shaft. EFFECT: higher safety, reliability and extended field of device application. 1 dwg
