At present, two conventional detection methods are given in the crane safety verification specification. These two methods are not only poor in measurement accuracy, but also difficult to operate. Method 1: a steel wire rope with a diameter of 1 mm was used. One end of the rope was tied with a small mound, and the other end was connected with a fixed microswitch (normally closed contact). The normally closed contact was connected to the descending circuit controlled by the contactor. The weight of the mound should be enough to make the switch act and cut off the descending circuit. When the rated load was measured, the small mound was placed on the load (weight). When the rated load dropped to a certain position at a slow speed, the small mound was separated from the load At this time, the descending circuit is cut off immediately, and the load begins to descend and brake immediately. After the rated load stops, the vertical distance between the small mound and the load is measured, which is the descending braking distance. Measure it several times and take the average value. Method 2: connect the counting circuit of the measuring instrument with the controller to ensure that the rated load drops slowly. The controller returns to the zero position and the counter counts from zero while the control circuit is powered off. During the test, the measuring wheel shall be touched at the outer diameter of the end of the drum (the contact force should not be greater than 60N). When the rated load stops braking at a slow descent speed, the counter's count value k is read as the original data of converted braking distance.
summary of the invention
In view of the shortcomings of the existing technology, the utility model provides a crane brake sliding amount detection device with less use of electronic components, simple structure, convenient operation, low price and more accurate.
The utility model has the following beneficial effects:
(1) Adopt mature pulling rope Displacement sensor It is low cost to measure the height of the connector during the whole process of crane sliding brake Displacement sensor Generally, it is several thousand yuan / piece, while the laser ranging sensor with the same accuracy and frequency is tens of thousands yuan / piece);
(2) The measuring connector is fixed on the side of the rated load to avoid damaging the displacement sensor due to load falling, so that the detection personnel can avoid the load and the measurement process is safer;
(3) It overcomes the influence of delay or error of electronic components in other measurement methods on the detection of brake slip, and ensures the detection accuracy.
Description of drawings
Fig. 1 is the structural diagram of the specific implementation mode of the utility model.
Among them: 1 rated load, 2 magnetic base a, 3 measuring connector, 4 rope displacement sensor, 5 magnetic base B, 6 metal mass block, 7 data acquisition card, 8 upper computer.
Specific implementation mode
As shown in Fig. 1, the device for detecting the brake sliding amount of the crane of the utility model, The data processing system refers to the data acquisition card 7 and the upper computer 8. The rated load 1 is suspended on the crane hook, the measuring connector 3 is fixed on the rated load 1 of the crane, and the rope displacement sensor 4 is placed under the measuring connector 3, and the rope displacement sensor 4 is connected with the data acquisition card 7 through the line, The data acquisition card 7 is connected with the upper computer 8. The data acquisition card reads out the displacement signal collected by the pulling rope displacement sensor, and displays or processes it through the upper computer. The upper computer can directly identify the starting time of the braking, that is, the deceleration start of the rope displacement sensor is the starting time of the braking, and the stop of the displacement sensor is the stop time of the braking, and then the braking sliding amount is measured. The measuring joint 3 is fixed on the side of the rated load 1, and the pulling rope displacement sensor 4 is vertically connected to the measuring joint 3. If the measuring range of the pulling rope displacement sensor 4 is insufficient, an extension line can be added; the measuring joint 3-end is fixed on the magnetic base A2, and the magnetic seat A2 is fixed on the side of the rated load 1; the other end of the rope displacement sensor 4 is fixed on the magnetic base B5, The magnetic base B5 is fixed on the metal mass block 6 on the ground, and the lower end of the metal mass block has a fixed foot for adjusting the level, and the surface of the metal mass block is adjusted to be horizontal, and the weight of the metal mass block is greater than or equal to 2.5 kg. The incremental encoder in the rope displacement sensor 4 converts the height change of rated load 1 into pulse signal, which is transmitted to the data acquisition card 7 for conversion, and then the information is transmitted to the upper computer 8 for reading or processing.