| 摘要 |
The invention concerns lifting and transporting machinery, particularly lifting crane capacity power limiting devices, which are used for stopping the mechanism of the lifting crane and turnover prevention in case of the weight exceeding the maximum capacity.The aim of the invention is to simplify the exploitation of the limiting device and to reduce its cost. The limiting device, whose fundamental flow chart is shown at the Figure 1, consists of three blocks: a tensiometric voltage transformer A1, a block of electronic control A2, and an operatively connected auxiliary console for control and direction A3. The block of electronic control A2 consists of a signal sender 1, an analogue-to-digital converter 2, both of which are plugged into the diagonal of the voltage transformer A1 scheme weak link, and a microcontroller 4, which is linked to a memory device 5 and executive relays 6. The electric signal of the tensiometric transformer A1, whose precision depends only on the tension-sensitive stability of the transformer A1, goes to the signal sender 1 and then to the analogue-to-digital converter 2. The control of the transformation process, calculation of the limiting device commutation points, weight calculation and conversion of these parameters into a consecutive code is done by the microcontroller 4. The microcontroller 4 compares the current value of the code with the code values kept in the non-volatile memory device 5 and sends a signal for blocking the lifting mechanism. The operatively connected auxiliary console A3 is used for examining the current code value and weight lifted, and turning on the calibration regime. This regime allows examination and correction of the relay 6 commutation code, zero value code, and tensiometric transformer A1 graduation coefficient values.<IMAGE>
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