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WPI Technical Theatre Handbook: Lifts
 
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Lifts

Often times, a fly system is not available for use for flying lighting or audio equipment. Some venues, such as WPI's Alden Hall, do not have any permanent provisions for lighting equipment in the house. Thus, it becomes desirable to be able to fly a lighting truss in front of the proscenium by some portable means. Several companies produce portable lifts that can be raised and lowered by manual, pneumatic, hydraulic, or electric means. Lifts go by several names, such as Genie Lifts (a trade name) or towers. One such lift is shown in figure 4.7.

Lifts have a set of feet that are adjusted to give stability to the structure. These feet typically immobilize the lift, as well as increase the footprint to reduce the chances of tipping. Once the feet are in position, the lift is typically raised enough for the load to be placed on it. Once loaded, they can be raised to the appropriate height for the task.

Figure 4.7: A Genie Industries SuperTower being used to hold lighting truss.
\begin{figure}\psfig{file=rigging/supertower.eps}\end{figure}

Usually lifts have a set of forks, akin to a forklift, for bearing a load. When placing a load on these forks, the load should be placed as close to the lift end of the fork as possible, to minimize the amount of stress on the fork.

Often, two lifts are used in conjunction to raise a span of truss. When this is the case, it often helps to have a person stand back and keep watch over how level the truss is. Hand signals are typically used to tell the people raising the truss to stop or go.

Figure 4.8: The forks of a lift. The top image shows the proper orientation of the forks.
\begin{figure}\psfig{file=rigging/fork.eps}\end{figure}

At WPI, Genie Lifts are often used to fly lighting truss. There are several important things to consider when using these lifts, as listed below:

  • Make sure forks are placed on the lift properly. There are two orientations for the removable forks. The appropriate one is with the offset from the fork to the mounting piece to be facing down, as in figure 4.8

  • Never dynamically load a lift. This means don't bounce on it, and don't suddenly drop loads on to it. Most lifts have built-in braking schemes that will lock the extension arm in place if it is dynamically loaded. This means that the lift can not be raised or lowered without manually releasing the brake, which is a long and involved process.

  • Be sure to lock the lift crank after lowering. The cranks on Genie lifts are ratcheting, but the ratchet releases when lowering the lift. This ratchet will not re-engage unless the crank is turned in the upwards direction. When a loud click is heard, the ratchet is re-engaged.


next up previous contents index
Next: Chain Motors Up: Fly Methods Previous: Counterweighted Fly Systems   Contents   Index
Steve Richardson 2000-07-06

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