Regulators inclined to let novel elevator ride on flexible cable

Feb. 19, 2004
An unusual inclinator -- a combination elevator and escalator -- ran afoul of state regulators who insisted on applying standard rules to its unconventional design.

One of only a few installed worldwide, the inclinator travels at a 30° angle like an escalator, but is fully enclosed in glass. The enclosure weighs approximately 3,000 lb and travels on steel tracks supported by a concrete raceway. A counterweight helps smooth the ride.
An Energy Chain cable carrier from igus Inc. houses and protects cables which must flex over a tight bend radius. The track extends approximately 120 ft and then doubles back on itself, requiring 250 ft of cable.

Otis Elevators, Farmington, Conn., designed the unit for the San Diego Convention Center. It uses Chainflex control cables from igus Inc., East Providence, R.I. ( But the continuous-flex cables had never been approved by OSHA for use in elevators. The State of California ordered a retrofit with standard elevator cables.

Problem: Typical elevator cables serve exclusively in hanging applications and usually have unrestricted room for sway. But on the inclinator they sat in a confined cable carrier and had to bend 180° to move people. So they tended to prematurely wear and cause breakdowns.

Fortunately igus had test results that proved the Chainflex cables, which are designed for small bending radii, met California OSHA standards. Says Kash Gopinath of Otis, "A similar inclinator currently runs in Europe with igus Chainflex cables. They easily flex enough ability to support the application." The company's CF5 and CF6 cables each have a bending radius of 7.5 times the diameter, and the CF1 has a bend radius of just five times the cable diameter.

Igus continuously performs rigorous flex testing in conditions such as extreme temperatures, erratic and high speeds, and a multitude of debris-infested environments. The CF5 cables, for instance, deliver more than 5 million cycles in short-travel applications. The cables are also recognized by UL and CSA. With the state of California satisfied, the inclinator has run smoothly with the Chainflex cables for nearly a year with no interruptions, outages, or downtime.

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