Method For Fixing The End Of Tower Crane Rope
At present, the rope end fixing method of lifting wire rope and boom head of tower crane mainly adopts the combination of wedge sleeve and rope clamp. The rope end fixation method of amplitude rope and amplitude trolley mainly adopts rope clamp. The following are introduced respectively. Wedge-wedge sleeve and rope clip combination fixing method
Wedge wedge sleeve at present, the combination of wedge wedge sleeve and rope clamp fixed method, domestic and foreign tower machine manufacturers take different methods. When the wedge and wedge sleeve are connected with the wire rope by foreign tower crane manufacturers, the wire rope clamp must not connect the stressed end and the fixed end together, as shown in Figure a. When the wedge and wedge sleeve are connected with the wire rope by domestic tower crane manufacturers, the wire rope at the stressed end and the fixed end are connected together by the rope clip, as shown in Figure b.
Figure a Combination of wedge sleeve and rope clip abroad
Figure b Combination of wedge sleeve and rope clip at home and abroad The advantages and disadvantages of these two fixing methods are discussed below. The advantage of the foreign method is that it can protect the wire rope well and reduce the damage of the wire rope. It will not cause the wedge wedge sleeve to tilt after the wire rope is loaded, and the wire rope at the outlet of the wedge wedge sleeve will not be damaged by additional bending pressure. The method of operation is that the tail of the fixed end of the wire rope should be pulled out of the wedge sleeve by a distance of at least several wire rope diameters, and the tail of the wire rope at the exit of the wedge sleeve must be immediately secured with a wire rope clamp. But with this method, if the end connection suddenly unloads, this will lead to the wedge loosening and even the possibility of falling out of the wedge sleeve. The advantage of the domestic method is that the wedge and wedge sleeve are connected reliably and the wedge will not fall out of the wedge sleeve. However, it will cause the wire rope to be tilted by the load wedge sleeve, and the wire rope at the outlet of the wedge sleeve will be damaged due to additional bending pressure. The structure of the wire rope often opens outside the curve, making the core of the wire rope visible, due to the frequent bending of the wire rope around the built-in wedge. Normally, this is not dangerous, but there is some damage to the structure of the wire rope. During the winding of the hoisting wire rope, the installer will repeatedly punch the wire rope and wedge in order to try to push the wedge sleeve. In this process, the wire wire on the surface of the wire rope will be damaged.
Tower wedge sleeve and rope card combination of rope card fixed tower crane whether lifting wire rope or variable wire are used rope card, the following focus on the fixing method of rope card.
Rope card fixed according to GB5976-20066 standard, rope card number is generally not less than 3-5, rope card spacing should be 6-7 times the diameter of the wire rope, the number of clips according to the diameter of the wire rope, ≤19mm at least 3, 19-32mm at least 4, 32-38mm at least 7. The wire rope card should be used in a matching way. The U-shaped ring should be partially stuck on the side of the rope head, and the press plate should be placed on the side of the main rope. The following points should be paid attention to when the wire rope clamp is used: a) The size of the clamp should be suitable for the thickness of the wire rope, and the inner clear distance of the U-shaped ring should be 1-3mm larger than the diameter of the wire rope. Too large clear distance is not easy to clamp the rope, which is prone to accidents. b) When attaching the rope clamp, the bolt must be tightened until the rope is flattened by 1/3-1/4 diameter. After the rope is stressed, the bolt of the rope clamp should be tightened again to ensure the joint is firm and reliable. c) The rope clip should be arranged in a straight line, and the U-shaped part should contact the rope head instead of the main rope, as shown in Figure A. If the U-shaped part is in contact with the main rope, it is easy to break the wire when the main rope is pressed flat. d) To facilitate the inspection of the reliability of the joint and the detection of the slip of the wire rope, install another rope clip about 500mm behind the last rope clip and release the rope end into a "safe bend", as shown in Figure b. In this way, when the wire rope of the joint slides, the safety bend is straightened first, and measures should be taken immediately. In addition to the above two rope end fixing methods, some auxiliary role of the tower crane wire rope will also use other rope end fixing methods, there are mainly the following methods:
1) Braiding method: (Figure a) After the end of the wire rope is bypassed the heart-shaped sleeve ring, the rope head is broken and inserted into the working rope strand respectively, and then tied tightly with a fine wire rope. The binding length L= (20-25) d, where d is the diameter of the wire rope. At the same time not less than 300㎜. 2) Wedge casing method: (Figure b) Fixed with a special diagonal wedge of steel wire rope. 3) Lead filling method: (Figure c and d) disassemble the end of the wire rope, insert it into the conical quilt and bend it into a hook shape, then fill it with lead and consolidate it. 4) The aluminum alloy indenter method (Figure e) divided the end of the wire rope into six strands, each strand left the head staggered, the length of the head does not exceed the length of the aluminum sleeve, and cut the rope core, turn 180 degrees, and then inserted into the main cable. It is then put into a casing, pressed into an oval shape on a steam hammer, and molded into a shape.
