In a theater fly system, a rope lock is a device used to prevent a rope, and the line set it controls, from moving. A rope lock is controlled by a steel handle that engages the lock when vertical and releases it when horizontal. The handle is typically red powder coated or covered by a red rubber grip. A steel, oval-shaped safety ring encircles both the rope and the handle to ensure that the lock cannot be accidentally released. Rope locks are mounted to a locking rail, which provides structural support and holds them at a convenient level for the stage crew.
Two metal cams, one stationary and one movable, are used to immobilize the rope. The position of the movable cam is controlled by the locking handle. When the handle is raised, the movable cam is pressed towards the stationary cam so as to grip the rope by compressing it between the cams. Conversely, the lock is released by lowering the handle, thus retracting the movable cam away from the stationary cam and releasing the grip on the rope. The position of the stationary cam can usually be adjusted with a socket head adjustment screw. This enables the spacing between the cams to be adjusted so that, when locked, the rope lock can accommodate ropes of different diameters.
Simple rope locks are designed to immobilize only balanced or slightly unbalanced loads; they will not hold significantly unbalanced line sets in place nor are they intended to be used for line set speed control. Most traditional rope locks are rated to hold a difference of 50 pounds (23 kg) or less. [1] For this reason, proper loading technique is essential for safe operation. Misuse of the rope lock is a common source of rigging accidents, especially among students.[ citation needed ] More complex rope locks are available which will prevent unlocking if the line set is excessively unbalanced. These load-sensing locks reduce the probability of accidents, but may cause inconvenient loading situations and are more expensive than simpler locks. Rope locks are also available which are designed to hold unbalanced line-sets and act effectively as a brake. [2]
Many rope locks provide a hole that will accommodate a padlock. When a padlock is installed, the control lever is locked in the vertical orientation and the line set cannot be moved. A rope lock is typically padlocked to prevent accidental movement of the set.
A knife is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone, over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin.
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the tension of a rope or wire rope.
The pin tumbler lock, also known as the Yale lock after the inventor of the modern version, is a lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key.
A lock is a mechanical or electronic fastening device that is released by a physical object, by supplying secret information, by a combination thereof, or it may only be able to be opened from one side, such as a door chain.
Running rigging is the rigging of a sailing vessel that is used for raising, lowering, shaping and controlling the sails on a sailing vessel—as opposed to the standing rigging, which supports the mast and bowsprit. Running rigging varies between vessels that are rigged fore and aft and those that are square-rigged.
Self-locking devices are pieces of rock-climbing equipment intended to arrest the fall of solo climbers who climb without partners. This device is used for rope solo climbing, for "ground-up climbing", and for "top rope solo climbing". To date, several types of self-locking devices have evolved.
The CZ 52 is a semi-automatic pistol designed by two brothers, Jan and Jaroslav Kratochvíl, in the early 1950s for the Czechoslovak military. Around 200,000 vz. 52s were made by Česká Zbrojovka in Strakonice from 1952 to 1954. Before standardizing on the 7.62×25mm vz. 52, the Czechoslovak military used several domestic and foreign pistol models in three different calibers. After 30 years of military service, the vz. 52 was eventually replaced by the 9×18mm Makarov caliber vz. 82.
A caster is an undriven wheel that is designed to be attached to the bottom of a larger object to enable that object to be moved.
A door handle or doorknob is a handle used to open or close a door. Door handles can be found on all types of doors including exterior doors of residential and commercial buildings, internal doors, cupboard doors and vehicle doors. There are many designs of door handle, depending on the appropriate use. A large number of handles, particularly for commercial and residential doors, incorporate latching or locking mechanisms or are manufactured to fit to standardised door locking or latching mechanisms.
A rotary combination lock is a lock commonly used to secure safes and as an unkeyed padlock mechanism. This type of locking mechanism consists of a single dial which must be rotated left and right in a certain combination in order to open the lock.
Padlocks are portable locks usually with a shackle that may be passed through an opening to prevent use, theft, vandalism or harm.
A latch or catch is a type of mechanical fastener that joins two objects or surfaces while allowing for their regular separation. A latch typically engages another piece of hardware on the other mounting surface. Depending upon the type and design of the latch, this engaged bit of hardware may be known as a keeper or strike.
A jackscrew, or screw jack, is a type of jack that is operated by turning a leadscrew. It is commonly used to lift moderate and heavy weights, such as vehicles; to raise and lower the horizontal stabilizers of aircraft; and as adjustable supports for heavy loads, such as the foundations of houses.
A vise or vice is a mechanical apparatus used to secure an object to allow work to be performed on it. Vises have two parallel jaws, one fixed and the other movable, threaded in and out by a screw and lever. The jaws are often flat but may have grooves, adapt to the shape of the workpiece or be custom made.
A fly system, or theatrical rigging system, is a system of ropes, pulleys, counterweights and related devices within a theater that enables a stage crew to fly (hoist) quickly, quietly and safely components such as curtains, lights, scenery, stage effects and, sometimes, people. Systems are typically designed to fly components between clear view of the audience and out of view, into the large space, the fly loft, above the stage.
An interlock is a feature that makes the state of two mechanisms or functions mutually dependent. It may consist of any electrical, or mechanical devices or systems. In most applications, an interlock is used to help prevent any damage to the machine or to the operator handling the machine. For example, elevators are equipped with an interlock that prevents the moving elevator from opening its doors and prevents the stationary elevator from moving.
Locking pliers are pliers that can be locked into position, using an "over-center" cam action. Locking pliers are available with many different jaw styles, such as needle-nose pliers, wrenches, clamps and various shapes to fix metal parts for welding. They also come in many sizes.
A scenery wagon, also known as a stage wagon, is a mobile platform that is used to support and transport movable, three-dimensional theatrical scenery on a theater stage. In most cases, the scenery is constructed on top of the wagon such that the wagon, and the scenery it supports, forms a single, integrated structure. Heavy duty casters are mounted to the underside of the platform so that the entire assembly can be quickly moved onstage or offstage, so as to facilitate rapid scenery changes during live productions. Scenery wagons are built in a wide range of sizes, ranging from less than one square foot up to the size of the playing area of the stage.
A tripod head is the part of a tripod system that attaches the supported device to the tripod legs, and allows the orientation of the device to be manipulated or locked down. Modular or stand-alone tripod heads can be used on a wide range of tripods, allowing the user to choose which type of head best suits their needs. Integrated heads are built directly onto the tripod legs, reducing the cost of the tripod system.
Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. A team of riggers design and install the lifting or rolling equipment needed to raise, roll, slide or lift objects such as heavy machinery, structural components, building materials, or large-scale fixtures with a crane, hoist or block and tackle.