What is a double purchase counterweight system?
Double purchase counterweight systems are sometimes used where the vertical travel of the counterweight arbor would be inadequate due to limited fly space or stage-level wing space. In systems of this type, the operating and lift lines are double-purchased so that the batten will travel twice the distance of the arbor.
What is a single purchase counterweight system?
Single purchase Counterweight The term single purchase indicates that it is a one-to-one system, not only in the weight as described above, but in its movement – if you pull the rope one foot, the load (scenery, for example) moves one foot. See double purchase counterweight to the right for further explanation.
What is a counterweight assist fly system?
A COUNTERWEIGHT FLY SYSTEM is a system for flying stage scenery by means of adjustable counterweights that are connected by cables running over loft blocks to battens which support the scenery. [ Merriam-Webster Dictionary] A counterweight is an equivalent counterbalancing weight that balances a load.
Where are the loft blocks in the fly system?
The loft wire lines run from the top of the cradle up to the top of the fly tower, around the head block, across the stage to evenly spaced loft blocks, then down, terminating at the batten, a load- bearing pipe that spans much of the width of the stage.
How does a double purchase system work?
Double purchase system: similar to reversed double pull block and tackle. In Block & tackle, rope doubles back through a floating pulley: 2 feet of rope is pulled for every 1 foot of rise of load, but your need only pull half as hard. The load is twice the weight of the pull, and moves only half as far.
How heavy is a stage weight?
A 12.6-kilogram (28 lb) stage weight supporting a scenery brace.
What is a double purchase system?
What is the difference between a single purchase and double Purchase fly system?
A single purchase would not allow full travel floor to grid, but double purchase with “muled” headblocks and loading rail halfway to the ceiling would allow full travel of the batten.
What are three parts of a counterweight fly system?
Counterweight Rigging System:
- Wire Rope and Rope Lock. Wire ropes are connected to the top of the arbor and travel up and over the head blocks.
- Counterweight Arbor. The counterweight arbor is loaded with weight equal to the production items hanging on the batten.
- Head and Loft Blocks.
How does a counterweight system work?
A counterweight is a weight that, by applying an opposite force, provides balance and stability of a mechanical system. The purpose of a counterweight is to make lifting the load faster and more efficient, which saves energy and is less taxing on the lifting machine.