| 摘要 |
FIELD: materials handling facilities. ^ SUBSTANCE: group of inventions is designed for protection of boom cranes at operation in confined areas and near electric power lines. According to first methods, sensor in form of electric antenna is mounted on boom to detect voltage, amplify it, filter and convert the voltage into emergency signal or crane motion blocking signal, additional vibratory displacements of sensor of sensor mounted on boom are provided. Reception of acoustic signal created by vibrating sensor and reflected from objects surrounding the crane can be provided and amplitude and/or Doppler frequency shift can be revealed and, basing on their values, distance to objects surrounding the crane or speed of their approach to crane can be determined, and at decrease of distance or increase of speed above tolerable values, emergency signal or crane blocking signal can be formed additionally. Forming of ultrasonic signal can be done not by mechanical vibrations of antenna, but by means of separate acoustic converter. Additional forming of modulation signals and acting by this signal onto amplitude or vibration frequency of sensor and determination of distance to objects surrounding the crane can be provided by measuring delay of received signal relative to modulation signal. According to second method, movement of crane boom and sensor mounted on boom are determined additionally and, depending on parameters of movement, sensor voltage amplification factor or indicated threshold level are determined. Direction of movement can be revealed additionally and, depending on said direction, sensor output voltage amplification factor or said threshold level can be changed. Revealing of boom movement can be done not by revealing the direction, but by revealing the speed, and sensor output voltage amplification factor can be increased or set threshold level can be reduced proportionally to said speed. Protection of crane from dangerous approach of boom to electric power line in traveling is provided owing to the fact that at revealing of boom movement speed, translation of crane is additionally taken into account. Direction of location of obstacle is revealed additionally and, if said obstacle approaches the crane with boom motionless, boom drive of crane is switched on to move in opposite direction to automatically prevent collision of boom with said obstacle. Device for implementing proposed method contains sensor mounted on boom and electronic unit whose input is connected to sensor and output is connected with input of emergency signaling or crane movement blocking device, and electromechanical converter connected to electronic unit. Sensor is fastened on electromechanical converter, and electronic unit is made for generating excitation signal of electromechanical converter. Acoustic signals can be received by means of additional acoustic converters connected to additional outputs of electronic unit. ^ EFFECT: provision of reliable protection of crane from dangerous approach to ac and dc electric power lines. ^ 15 cl, 1 dwg |
