Scrambler (ride)

The Scrambler, Twist (in the UK), Twister, Cha Cha (in Australia), Sizzler, or Merry Mixer, is an amusement ride in which suspended riders spinning in cars experience centrifugal force, while spinning along two separate axes. Riders are seated in small carriages clustered together and connected by beams at the top to a central point. The clustered vehicles are spun in one direction, while the ride as a whole spins in the opposite direction. There are a number of variations of the design.
Early history.
The first scrambler was invented by Richard Harris of Georgia and installed at Lakewood Fairgrounds in 1938. Two additional rides were built and sold in the following two years. In 1941, Harris was granted a U.S. patent for the design, which was then acquired or licensed by the Eli Bridge Company.
In late 1953, the Eli Bridge Company road-tested its Scrambler ride, and sold the first five by the end 1954. The original ride had a total of 12 cars distributed among its three arms with a capacity of 24 adults or 36 children. The entire ride rotated clockwise at 9–12 revolutions per minute.
The Eli Bridge Scrambler had one of its first major showings at the 1955 Florida State Fair, where it grossed $1,700 (at 25 cents a ride) in a single day and interested many additional buyers.
The rides first appeared in the UK in 1959, when they were manufactured by Edwin Hall under license from the Eli Bridge Company. Eli Bridge rides were first imported in 1979.
Variants.
Grasscutter.
A grasscutter scrambler has a basic frame shape and no platform and is driven by a lower arm assembly. This type of ride is extremely popular in the United States.
Sizzler.
A Sizzler is a ride which has thicker arms and a platform. It was when these type started being manufactured, the manufacturers concentrated on the ride aesthetics. Concerns have been raised about its safety, as the ride has been involved in at least six fatalities since 1997. 
Gee Whizzer.
The 'Gee Whizzer' derivative was constructed and commissioned by the operators King Carnival amusements of Tasmania, Australia during the 1950s. The project was carried out by rail engineers who utilised rail and tram parts which were common for the era. This machine is currently the largest and fastest of the variants utilising a unique fully suspended balanced single sweep arm design, driven from the top resulting in no lower arm assembly. The centre support core is fully independent and does not require a support deck, instead eight extended stabilisers are fitted to the core during assembly. Only one of these machines are known to be in existence.
Cyclone.
A Cyclone, also known as a Lifting Twist, manufactured by ARM UK, has very much the same function and appearance as a normal Sizzler, except that the centre structure begins to lift with the cars once it reaches up to normal speed until it reaches above the fence level, where it remains for the duration of the ride. They are considerably fast when they reach full speed, although they normally slow down first so riders can brace for the full speed. After the full speed part is over, the centre structure begins to lower back to platform level as the ride slows down to a stop. Only one of these Cyclones currently exist in the world.