Rope lock
Encyclopedia
A rope lock is a device used in a counterweight fly system
Fly system
A fly system, flying system or theatrical rigging system, is a system of lines , blocks , counterweights and related devices within a theatre that enable a stage crew to quickly, quietly and safely fly components such as curtains, lights, scenery, stage effects and, sometimes, people...

 to prevent a rope, and the lineset it controls, from moving. It consists of two metal cams which are pressed towards each other so as to grip the rope by compressing it. A long steel handle—which is typically red powder coated
Powder coating
thumb|right|Aluminium extrusions being powder coatedPowder coating is a type of coating that is applied as a free-flowing, dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler...

 or covered by a red rubber grip—engages the lock when vertical and releases it when horizontal. An oval shaped steel ring encircles both the rope and the handle to ensure that the lock cannot be accidentally released.

Rope locks are designed to only hold in-balance loads. They are not designed to keep an out-of-balance line set in place. Most rope locks are only rated to hold a 40 pound
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

 (20 kg
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...

) difference. Misuse of the rope lock is a very common source of rigging accidents, especially among students. For this reason, proper loading technique is very important for safety in theaters.

Some more expensive rope locks exist which will not allow an operator to unlock it if it is too out-of-balance. These reduce the number of accidents, but also cause inconvenient loading situations. Expense also prevents many theaters from adopting them. Most rope locks have a hole through them to allow the set to be padlock
Padlock
Padlocks are portable locks used to protect against theft, vandalism, sabotage, unauthorized use, and harm. They are designed to protect against some degree of forced and surreptitious entry.- History :...

ed closed, to prevent accidental use of the set. This may be used, for example if a set piece is flown underneath the batten, and flying the batten would cause a collision.

Rope locks are attached to a locking rail which provides structural support and holds them at a level easily accessible for rail operators. When being installed, ropes must be threaded through the rope lock and the safety before it is tied off to the arbor.
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