Technical Information

The first rope installation as well as the later rope changing operations still belong to the relatively risky works in a shaft. In order to realize this difficult task on multi-rope hoisting systems quickly and safely in deep shafts, corresponding auxiliary devices have to be used. The need for more simple handling, economic realization and safe procedures when dealing with high loads can only be met by using continuously improved machines and adequate auxiliary devices.

The principle of the friction winch is based on the transmission of forces from the drums to the rope by friction (see sketch). The value of the traction force S₁ depends on the number of rope windings on the drums, the friction value between rope and drum lining, as well as the retaining force S₁. The required retaining force is obtained by means of hydraulically operated pressure roller chains assuring that the ropes of the last two windings are exactly pressed into the rope grooves. Thus the ropes can easily be moved from the supply reelers as they are operated almost load free (S₂).

The design of the friction winch does not only allow the lowering of ropes into the shaft, but also the pulling of the ropes in reverse mode. The friction winch is able to simultaneously install different numbers of ropes, in the case of Palabora up to 6 ropes. It can ideally handle hoisting and balance ropes as well as guide ropes.

The winch is typically designed as a mobile unit adapted to any specific requirements of road traffic and can, therefore, be used flexibly and quickly at other shafts. The travelling gear may optionally be integrated in the frame structure and hydraulically lowered so that the friction winch can be set and anchored onto the foundations quickly.

The two friction drums of the winch are driven by a DC motor and 2 planetary gears. Power transmission from the drive at the pinion end to the second drive is realized for synchronisation by means of a sufficiently dimensioned cardan shaft.

All operations and functions are controlled and monitored from the control stand. The winch may equally be applied for different rope diameters due to exchangeable drum friction-linings. Friction winches with drums in an inclined position, with respective linings, assure the careful installation and handling of flat ropes.