Table of Contents
In this section, you can see a summary of various events that in one way or another were associated with the fall of construction equipment – large-sized cranes.
Safety devices of the Astro crane construction
Devices that ensure safe operation of the crane include safety devices, indicators, limiters of operating positions of mechanisms and load limiters. On cranes of various types, safety devices can be of different design and placed on different parts of the crane.
Safety devices include rail grips that hold the valve inoperative from moving along the crane track under the influence of wind; safety supports used to describe the crane in case of breakage of the:
- running wheels or their axles
- dead ends.
Limiting the movement of the crane along the track, dropping shields prevent foreign objects from falling under the travel wheels.
The indicators used on the cranes are the indicators of the number of revolving of the freight winch (for cranes, the lifting mechanism of which consists of two winches with autonomous control), the departure and wind force – anemometers.
The indicator of the number of revolving of the winch consists of a potentiometer, the lead head of which is rotated being connected with the winch reel of the drive limit switch and installed in the cockpit of a voltmeter crane with a scale graduated in the number of revolving of the winch reel.
The departure indicator mounted on cranes with a lifting boom consists of a shaft connected to the bracket on the boom through the lever and pull rod. On the shaft, the arrow is fixed, indicating the flight along the graduated scale. The stopper is adjusted by changing the length of the traction with the help of the drive.
On cranes with a beam arrow, the departure indicators (cargo truck position indicators) are arranged in a manner similar to the index of the speed of the winch reel. The lead of the potentiometer at these pointers is connected with the reel of the winch of the freight trolley, and on the scale of the voltmeter, the departure is indicated.
In the thirties of the twentieth century, tower cranes thoroughly occupied a niche in the construction industry, and they keep it up to now. The first models of tower cranes were not as efficient and productive as modern analogs, besides, they had a complex sequence of operations during assembly and disassembly at the construction site, which increased the labor costs of companies. Despite the shortcomings and difficulties with the operation of the first production models, the tower cranes gave undeniable advantages in the speed and convenience of the construction process. This allowed to develop and improve this class of hoisting machines. Now it is difficult to imagine any construction without the use of effective lifting equipment because many materials lifted have a mass of several tons. There are just no alternatives to tower cranes for such parameters as efficiency, productivity, cost and time for assembly-disassembly. The modern tower crane is one of the main tools of any construction, from the creating of a small kindergarten to the construction of a hundred-meter skyscraper.