First, the crown block traction method
When hanging the optical cable, the cable tray to be placed should be erected first, and the big pulley for placing the optical cable should be fixed on the poles at the top and bottom. Hanging lines on each crossbar, each 10 ~ 20.
M Hang a small pulley (guide pulley) and put the traction rope into the small pulley. Then make a traction head, connect the traction rope with the optical cable, and prepare for deployment.
When manual traction is adopted, the optical cable reel is manually pushed to gradually release the optical cable, and then a person is placed on every other pole to assist traction (guide pulleys are installed on corner poles if necessary). Gradually tighten the traction rope at the traction end, so that the optical cable is slowly paid out. In order to fully ensure the safety of optical fiber, three contact telephones are set at the pay-off end, the take-up end and the cable traction head of the optical fiber line, and the communication is kept smooth at all times. When a single optical cable is long, it is generally laid twice: after the first half is laid, the word "8" is inverted on the spot, and then the second half is laid in the opposite direction.
When mechanical traction is used, the main engine of mechanical traction should be placed at the cable receiving end, and the auxiliary traction machine should be placed at the appropriate position of the erection line. Erect the cable drum to be laid at the cable laying end, manually push the cable drum to lay the cable gradually from the top of the drum, and use mechanical traction instead of manual traction to achieve the purpose of laying the cable. When making the traction end, it must be ensured that the traction force mainly acts on the steel bar of the optical cable. Under the limit of the allowable traction of optical cable, the length of optical cable laying at one time should depend on the terrain conditions. In addition, the traction speed of the cable tractor should be determined in advance. When the traction tension exceeds the standard, there should be an automatic cut-off or alarm device.
After laying the optical cable, the length of the optical cable required for the joint and the length of the optical cable reserved for each pole shall be reserved. Finally, hang the winding end of the remaining cable on the telephone pole.
When laying suspended overhead cables, telescopic bends should be made on poles. In the middle load area, heavy load area and overweight area, it is generally required to reserve each pole; Light load area, one reserved every 3 ~ 5 poles; For ice-free areas, it cannot be reserved (but the optical cable should not be pulled too tightly when laying, and attention should be paid to natural sagging). See Figure 1 for the specifications of the telescopic bend of the optical cable on the pole. The middle part of the pole should be protected by polyethylene corrugated pipe, and the reserved length is 2.
M (generally not less than 1.5m). Both sides and binding parts should be reserved, and care should be taken not to tie them to death, so that they can freely expand and contract when the temperature changes, and play a role in protecting the optical cable. When the optical cable passes through the "X" messenger wire or the "D" messenger wire, a protective tube should also be installed.
Hooks are generally used to fix and hang overhead cables. The spacing between optical cable hooks is 50 cm, and the allowable deviation should not be greater than 3.
Cm. Hook direction on the suspension line should be consistent, hook plate should be complete, and there should be no mechanical damage. The distance between the first hook on both sides of the pole and the messenger wire splint should be 25 cm, and the allowable deviation should be no more than 2 cm.
Second, the cable drum moving release method
This suspension method is to put the optical cable tray on the truck (fix one end of the optical cable on the suspension wire of the pole), manually push the optical cable tray, so that the optical cable is placed along the overhead pole road, and at the same time hang the optical cable on the suspension wire. After laying one pole distance, you can fix the optical cable on the suspension line and start laying the next pole distance. This arrangement method is simple to operate, but the use of trucks for erection is limited by conditions. When using this method, the following conditions should generally be met.
① The width of the road can allow vehicles to drive.
(2) The distance between the overhead pole road and the roadside is not more than 3m. ..
③ Erection is partially barrier-free.
(4) messenger wire is located at the lowest point of other lines on the pole road.