Chairlift

An elevated passenger ropeway, or chairlift, is a type of aerial lift, which consists of a continuously circulating steel wire rope loop strung between two end terminals and usually over intermediate towers.

They are the primary on-hill transport at most ski areas (in such cases referred to as 'ski lifts'), but are also found at amusement parks and various tourist attractions.

Depending on carrier size and loading efficiency, a passenger ropeway can move up to 4,000 people per hour, and the fastest lifts achieve operating speeds of up to 12 m/s (39.4 ft/s) or 43.2 km/h (26.8 mph).

[1] The two-person double chair, which for many years was the workhorse of the ski industry, can move roughly 1,200 people per hour at rope speeds of up to 2.5 m/s (8.2 ft/s).

[2] The four person detachable chairlift ("high-speed quad") can transport 2,400 people per hour with an average rope speed of 5 m/s (16.4 ft/s).

[3] Some bi- and tri-cable elevated ropeways and reversible tramways achieve much greater operating speeds.

The rope stretches and contracts as the tension exerted upon it increases and decreases, and it bends and flexes as it passes over sheaves and around the bullwheels.

The number of towers is engineered based on the length and strength of the rope, worst case environmental conditions, and the type of terrain traversed.

Drive terminals can be located either at the top or the bottom of an installation; though the top-drive configuration is more efficient,[7] practicalities of electric service might dictate bottom-drive.

In most localities, the prime mover is required to have a backup drive; this is usually provided by a Diesel engine that can operate during power outages.

The purpose of the backup is to permit clearing the rope to ensure the safety of passengers; it usually is much less powerful and is not used for normal operation.

Some chairlifts are also equipped with an auxiliary drive, to be used to continue regular operation in the event of a problem with the prime mover.

The restraining bar is useful for children—who do not fit comfortably into adult sized chairs—as well as apprehensive passengers, and for those who are disinclined or unable to sit still.

In addition, restraining bars with footrests reduce muscle fatigue from supporting the weight of a snowboard or skis, especially during long lift rides.

Vermont and Massachusetts state law also require the use of safety bars,[citation needed] as well as most Ontario and Quebec in Canada.

[citation needed] Restraining bars (often with foot rests) on chairlifts are more common in Europe and also naturally used by passengers of all ages.

Among more notable bubble lifts are the Ramcharger 8 at Big Sky Resort, North America's first high speed eight pack; and the longest bubble lift in the world is the American Flyer high speed six pack at Copper Mountain.

[10] Many—if not most—installations have numerous safety sensors which detect rare but potentially hazardous situations, such as the rope coming out of an individual sheave.

In June 1990, Winter Park Resort performed planned destructive safety testing on Eskimo, a 1963 Riblet Tramway Company two-chair, center-pole fixed grip lift, as it was slated for removal and replacement with a high-speed quad Poma lift.

If the emergency brake/stop button is depressed by any control panel, the lift cannot be restarted until the hydraulic brake is hand-pumped to proper operating pressure.

In May 2006, a cable escaped the sheaves on the Arthurs Seat, Victoria chairlift in Australia causing four chairs to crash into one another.

If a misload or missed unload occurs—or is imminent—they slow or stop the lift to prevent carriers from colliding with or dragging any person.

Communication is also used to warn of an arriving carrier with a passenger missing a ski, or otherwise unable to efficiently unload, such as patients being transported in a rescue toboggan.

An additional electric motor, diesel or gasoline engine—even a hand crank—allows movement of the rope to eventually unload passengers.

Electromagnetic induction testing detects and quantifies hidden adverse conditions within the strands such as a broken wire, pitting caused by corrosion or wear, variations in cross sectional area, and tightening or loosening of wire lay or strand lay.

[21] If passengers fail to unload, their legs will contact a lightweight bar, line, or pass through a light beam which stops the lift.

For fixed grip lifts, a walkway can be designed so that it moves at a slightly slower speed than the chairs: passengers stand on the moving walkway while their chair approaches, hence easing the boarding process since the relative speed of the chairlift will be slower.

The technology, which was further developed by the people living in the Alpine regions of Europe, progressed rapidly and expanded due to the advent of wire rope and electric drive.

Curran re-engineered the banana hooks with chairs and created a machine with greater capacity than the up-ski toboggan (cable car) and better comfort than the J-bar, the two most common skier transports at the time—apart from mountain climbing.

The patent for the original ski lift was issued to Mr. Curran along with Gordon H. Bannerman and Glen H. Trout (Chief Engineer of the Union Pacific RR) in March 1939.