Constant Concern of Runaways
Since the counterweight rigging system was introduced to the theatre years ago, the runaway arbor has remained one of its most pressing hazards. It is extremely difficult to stop thousands of pounds of falling metal, which has resulted in prevention procedures and damage mitigation being the primary ways of dealing with them.
The Arbor Trap Mitigates Runaways
A runaway arbor results from a lineset in which the arbor becomes significantly heavier than its load. Such an imbalance is caused by one of two procedural errors – either the load is removed before the counterweight is removed, or counterweight is added before the load is added.
Technological innovations such as spreader plates and locking plates, which are incorporated into the conventional rod arbor, are intended to mitigate the damage done in the event of a runaway, by preventing bricks from flying out of the arbor on impact. However, no technology has existed to successfully mitigate the actual occurrence of runaways – until now.
The Arbor Trap works by detecting imbalance, either when load is removed or counterweight added. As the arbor becomes heavier than the load, the arbor settles into the trap. The trap prevents the release of the arbor until the lineset is rebalanced, at which time the trap can be released and the lineset operated normally.
The Arbor Trap, as an out-of-balance-detecting device, has significant advantages over existing safety devices which detect overspeed arbors. An overspeed-detecting device requires that the line go into free-fall before engaging. In this case, both the line set and the device experience damaging shock loading when arresting the runaway. On the other hand, an out-of-balance detecting device simply cannot release a heavy arbor, and thus a runaway cannot even begin – and both the lineset and device remain undamaged.
The damage done by a single runaway can easily amount to the cost of a full set of Arbor Traps – not counting the immeasurable potential damage to human life. Protect your theatre and your workers with Arbor Trap.