The manufacturing processes used to make Ferris wheels varies with the design of the wheel and the manufacturer. Most of the components are built in different parts of the shop before they are brought to the main construction area for final assembly. Here is a typical sequence of operations used to build a transportable Ferris wheel used in carnivals and county fairs. In operation, the wheel described is about 60 ft (18.3 m) in diameter with a capacity to carry up to 48 riders in 16 seats.
Building the chassis
1 The trailer chassis forms the base for the Ferris wheel, both when it is being transported on the highway and when it is in operation. The component parts of the chassis are cut to length, either with a metal-cutting saw or with a torch, and are welded together. Two vertical support posts are welded to the forward section of the chassis. These posts hold the upper end of the two-wheel support towers when they are in their lowered position for travelling.
2 The completed chassis is then sandblasted to remove any scale and spatter formed during the welding operation. This ensures a smooth surface appearance and prevents the scale from chipping off later and leaving patches of bare steel.
3 The chassis is then coated with a rust-inhibiting primer. After the primer has dried, one or more coats of finish paint are applied in the desired color.
Installing the towers
4 The two-wheel support towers are fabricated and painted elsewhere and are lifted into position on the chassis. The lower ends are attached to hinges on each side of the chassis, and the upper ends rest on the two support posts. The towers include ladders welded along one edge to provide access to the electrical rings and brushes at the wheel hubs and to the electrical drive motors and wheels that tum the drive rim on each side. The center axle is then installed between the wheel hubs at the tops of the two towers.
5 A long hydraulic cylinder is attached between the chassis and the wheel support tower on each side, about halfway along the length of the tower. These hydraulic cylinders are used to raise the towers into their upright position when the Ferris wheel is being set up for operation. The cylinders are secured in place with a pivot pin at each end.
6 A separate lateral support arm is attached near the top of each wheel support tower. These arms each consist of two pieces of square tubing, with one piece slightly smaller in cross section so it slides inside the other. When the wheel support towers are raised for operation, the lateral support arms are pulled out to the side and the inner section of each is extended and locked in place with a pin. Two other pieces of square tubing are hinged to the chassis frame on each side and swing out to attach to the bases of the lateral supports. This gives the Ferris wheel the required side-to-side stability it needs.
7 Hydraulic and electrical lines are routed inside the chassis frame pieces where they will be protected. The operator's control station is installed and connected. The chassis axles, brakes, tires, wheels, and stabilizer jacks may be installed at this time or they may be installed after all other work is complete.
Installing the spokes
8 Sixteen pairs of spokes run from the center hubs at the tops of the towers out to the seats. To install the spokes in the factory, the first pair of spokes is laid flat on the factory floor, and two crossmembers are installed between the spokes. One crossmember is located at the point where the drive rims will be attached, which is about 5 ft (1.5 m) in from the outer end of the spokes. A pair of curved sections of the drive rims are also bolted in place on each side at the same point. Only one end of the drive rim sections is bolted, leaving the other end free. This procedure is repeated for the remaining spokes, crossmembers, and drive rim sections until they form a stack. The inner ends of each pair of spokes are pinned to the pair below it. V-shaped lighting booms are installed between the center of every other outer crossmember as the stack is assembled. This overlapping pattern of lights produces a double-star effect.
9 The stack is then lifted onto the trailer with an overhead crane, and the top pair of spokes is pinned to the hubs. In operation, the spokes are all pulled into the vertical position when the towers are raised. The spokes are then pinned to the hubs, one pair at a time, and the free ends of the drive rim sections are swung down and bolted to the adjacent spokes to form the wheel—like a paper fan being unfolded.
10 Electrical cables are connected from the electrical rings at the wheel hubs to each lighting boom. Mechanical support cables are installed between the ends of the spokes around the outer circumference of the wheel. Other mechanical cables are installed in an x-pattern between each pair of spokes to give additional stability.
Finishing the wheel
11The entrance and exit stairs and walkways, safety fences, and trim pieces are fabricated, painted, and installed. The seats are fabricated and painted. In operation, four of the seats are carried attached to the wheel. The remaining seats are carried separately on the trailer and are manually lifted and pinned into place after the wheel is erected.
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