Elevator ropes

Safe using of the various lifting machines like cranes, mine hoists, air rope ways, elevators etc. depends on steel wire ropes durability. Ropes are non repairable components of the machines. That is why the ropes worn or failed must be changed. 

Performance of Cured Resin Sockets. Poured resin sockets may be moved when the resin has hardened. After ambient or elevated temperature cure recommended by the manufacturer, resin sockets should develop the nominal strength of the rope and should also withstand, without cracking or breakage, shock loading sufficient to break the rope. Manufacturers of resin socketing material should be required to test to these criteria before resin materials are approved for this end use. 

Elevators of this type are normally rope driven and are the most common drive used in elevator installations. The gearbox is fitted with a grooved traction sheave on which a series of steel ropes are wound. The ropes are attached to the top of the elevator car, wrapped around the traction sheave (and occasionally secondary sheaves) and attached to a counterweight of equal mass to the car and a percentage of its rated load (normally 40 per cent). 

Some physical activities can be very simple to add to the daily routine—taking the stairs instead of the elevator, or walking instead of driving, are good examples. Eventually, a person can add more strenuous activities to his or her routine, such as speed walking, bicycling, tennis, and jumping rope. 

For example, if the rope of an elevator breaks and the elevator then falls freely, things in the elevator behave as if there were no gravitational field. If a person in the falling elevator drops a parcel, it will not fall to the floor of the elevator because the elevator itself is falling freely and so moves at the same rate as the parcel. 

The curtains are stored in two storerooms, constructed in 1948 and 1957 (Figure 10). They are stored on curtain racks attached to a sliding carriage with permanent curtain rings. The carriages are raised and lowered by means of ropes and pulleys and are locked in place to boating cleats. The curtain racks may be pulled out into the room to have the curtains changed. When a curtain set is taken off or placed back on the rack, a white mattress pad is spread out on the floor, and the curtain carefully placed onto it. The curtain can be transferred onto a special cart that fits the museum elevator and passes easily over the museum runners. 

In recent years, poly(p-phenylene benzobisoxazole) (PBO) fibers have become prominent in high strength applications such as body armor, ropes and cables, and recreational equipment. However, degradation of PBO fiber mechanical properties following exposure to moisture has been documented by the manufacturer (7) and at least one failure of PBO-based body armor in the field has occurred (2). The objectives of this study were to compare changes in mechanical and chemical properties of yams extracted from PBO-based body armor that was penetrated by a bullet in the field approximately 6 months after being deployed, with PBO-based body armor panels of the same model aged in the laboratory under elevated temperature and moisture conditions. 

The main task is to determine the measures that should be taken to prevent these kinds of accidents. The best way to prevent a fall is by providing safeguards. Workers working at an elevation should be provided a safeguard net and fences. They may be tied with ropes as well. Then-mental and physical fitness should be checked regularly to determine whether they can work at elevations and can sustain vertigo (a dizzy, confused state of mind). 

Workers who are not properly trained should not be allowed to work on elevated sites. A worker should be chosen for work on bridges and elevated structures depending on psychological and physiological states. Workers can be provided with emergency nets, coiled knotted ropes, ladders, fire escapes, and parachutes. 

A statistical study of mine-hoist wire ropes showed that 66% of the ropes exhibited greatest loss in strength in the portion of the rope in contact with the shaft environment during its service life (26). The Mine Safety and Health Administration (MSHA) of the US Department of Labor requires that wire ropes in service be visually examined for structural damage, corrosion, and improper lubrication or dressing (27). MSHA also requires performance of careful nondestructive testing (NDT) every 6 months and cites one instance where a contractor reported that four ropes were in acceptable condition for use in an elevator shaft. However, less than 6 weeks later, one of the four 12.7 mm (0.5 in.) diameter ropes broke and another was severely corroded with several broken wires (28). 

As a filter medium, for example, acrylics lack sufficient abrasion resistance and dimensional stability at elevated temperatures to find universal acceptance. As a fiber for ropes and fish nets, acrylics excel in resistance to weathering but lack sufficient tensile strength for many applications. High-tenacity, continuous filament nylon, polyester, and UV-stabilized polyolefin are generally chosen where tensile strength is critical, even though the stability of these... 

A recent innovative machine-room-less traction elevator (ISIS) from ThyssenKrupp takes full advantage of the properties of p-aramid in the design of the hoist cable and associated traction sheaves [130-133]. The cable has three times the life of a steel rope, is smaller in size, and weighs 90% less than a steel rope at a comparable strength rating. The smaller size permits the use of smaller sheaves thereby decreasing torque requirements and operating costs. No lubrication is required because the inner strands are Teflon coated. Finally, the cable transmits less noise and provides a smoother, quieter ride. 

A major use of ropes is in lifts (elevators) and cranes, where heavy weights have to be raised and lowered. The requirement is for high strength and low extensibility plus resistance to flex fatigue in motion over pulleys and to corrosion. Heat can be a problem in deep mines or in braking an elevator in free fall. As skyscrapers and deep mines came into use in the 19th century, steel wire ropes were the natural choice. Industrial conservatism means that they continue to dominate the market. The mechanics are stress-driven and extension is a nuisance so that the high-performance fibres, such as aramid and HMPE, should be contenders. 

Otis had built there an open elevator of his new type, powered, like those of that time, by a steam engine. While he himself was using it and being transported by it up and down, he suddenly cut the lifting rope under the eyes of an astonished public, in order to demonstrate the good operation of his safety brake and, at the same time, his full confidence in it. 

Incidentally, the brake was based on a steel leaf spring, of the type currently used on coaches, inserted between the lifting rope and the elevator so that, once the load was lost due to the break of the rope, it automatically extended laterally pushing two wedges in two mating racks fixed on the walls (or columns) of the elevator pit. 

Traction elevators are a type of Koepe hoist which generally do not use balance ropes. In comparison with Koepe mine hoists, elevators have very light ropes and heavy cars and... 

Exposure to winters combined with potential product contamination on the hoist ropes has swayed recent installations towards enclosed ropeways to prevent rope slippage. Admittedly, a lot of the issue is the fear of the unknown due to limited available references. An added benefit of the ropeways has been permanent stair access to the upper headframe during sinking, construction and operational activities. Figure 3 shows headframe elevations complete with A-frame legs, hoist houses and ropeways. 

---