Sight & Sound
the counterweights. Think back to your high school physics: When the load is in proper balance, it is relatively easy to move the load by pulling on the hand line. If you have to struggle to move the load, the set is out of balance. By the same token, if the set moves by itself or takes virtual- ly no effort to move, it is also out of balance. Either of these situations is potentially dangerous.
Here’s where gravity comes in: The heavier side of the system will always move downward, while bringing the lighter side up—and the more the system is out of balance, the faster it will do this.
A loading gallery is a necessity for any counterweight rigging sys- tem. In order to properly balance (counterweight) the load on the batten, it is necessary to add or remove weight from the counterweight arbor. This must be done at the same time the weight is being changed on the batten, so that the system is always in balance.
Determine the permanent counter- weight. Identify the empty trim (pipe) weight for each batten, so the trim weight will not be mistakenly removed. Every set will have permanent counterweight on the arbor to balance the empty batten. Consider painting these permanent weights red or yellow, to signal that they should not be removed from the arbor. Strapping them in place with flat metal bands or cable ties is also a good idea. Keep weights in neat stacks at the side of the loading gallery—but no higher than the toe boards at the bottom of the gallery. This will keep operators from accidentally kicking them off the bridge. Don’t overload the gallery. There should be a sign on the gallery to tell you how much load the bridge will carry. Keep your mind on the job. Make sure a responsible adult is in charge of the coun- terweight system, and keep distractions to a minimum backstage. Wear heavy-duty work gloves and closed, hard shoes. Fingers and toes can be in peril during any production.
The loading gallery must be designed by a structural engineer who understands theatrical rigging systems. Most of your extra weights will be stored on the bridge, so must be designed properly.
How can you determine what the load on the batten actually weighs? As you load or unload counterweights, feel the system by seeing which side of the hand line is in tension. When a set is in balance, both lines have the same amount of tension, and they move fairly easily. Once you have balanced the load, you can count the counterweights to get a rough weight.
Keep these basic issues in mind as you work with your counter- weight rigging system:
Know your load limits. Each line set has a specific load capacity; make sure these are written on the batten end caps and on the index cards under each rope lock at the lock rail. Do not exceed these limits, as they can affect the structure of your building.
Train and authorize the operators. Keep a log that details which of your staff members and volunteers have had official training on use of the rigging. Choose one of these people to supervise rigging operation during productions.
Rigging Operation: Attaching Loads to Battens and Loading Arbors
These steps are listed in J. R. Clancy’s Operation & Maintenance Manual for Single Purchase Counterweight Rigging System with Loading Bridge. You can download the entire manual at www.rigging-safety.com. If you believe your system is double-purchase, or if your system does not have a loading bridge, you’ll find manuals for these systems at this Web site as well.
Attach the load to the batten.
Bring the empty batten to the FULL IN (or Low Trim) position just above the stage floor.
Engage the rope lock and set the oval safety ring.
In the loading gallery, remove all the weight from the arbor except for the permanent “pipe weight.” Now the batten is the same weight or heavier than the arbor, so that the system is in a stable condition.
Securely attach the scenery, drapery, track, lights, etc., to the batten. Be sure that the
September 2009 / Church & Worship Technology