Rope lock

A rope lock is a device used in a counterweight fly system to prevent a rope, and the line set it controls, from moving. The 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 operators.

Locking mechanism

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.

Rope

A rope is a group of yarns, plies, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting, but are too flexible to provide compressive strength. As a result, they cannot be used for pushing or similar compressive applications. Rope is thicker and stronger than similarly constructed cord, line, string, and twine. Ropes made from metal strands are called wire rope.

Construction

Rope may be constructed of any long, stringy, fibrous material, but generally is constructed of certain natural or synthetic fibres. Synthetic fibre ropes are significantly stronger than their natural fibre counterparts, but also possess certain disadvantages, including slipperiness.

Common natural fibres for rope are manila hemp, hemp, linen, cotton, coir, jute, straw, and sisal. Synthetic fibres in use for rope-making include polypropylene, nylon, polyesters (e.g. PET, LCP, HDPE, Vectran), polyethylene (e.g. Dyneema and Spectra), Aramids (e.g. Twaron, Technora and Kevlar) and acrylics (e.g. Dralon). Some ropes are constructed of mixtures of several fibres or use co-polymer fibres. Wire rope is made of steel or other metal alloys. Ropes have been constructed of other fibrous materials such as silk, wool, and hair, but such ropes are not generally available. Rayon is a regenerated fibre used to make decorative rope.

Rope (data structure)

In computer programming, a rope, or cord, is a data structure composed of smaller strings that is used for efficiently storing and manipulating a very long string. For example, a text editing program may use a rope to represent the text being edited, so that operations such as insertion, deletion, and random access can be done efficiently.

Description

A rope is a binary tree having leaf nodes that contain a short string. Each node has a weight value equal to the length of its string plus the sum of all leaf nodes' weight in its left subtree, namely the weight of a node is the total string length in its left subtree for a non-leaf node, or the string length of itself for a leaf node. Thus a node with two children divides the whole string into two parts: the left subtree stores the first part of the string. The right subtree stores the second part and its weight is the sum of the left child's weight and the length of its contained string.

The binary tree can be seen as several levels of nodes. The bottom level contains all the nodes that contain a string. Higher levels have fewer and fewer nodes. The top level consists of a single "root" node. The rope is built by putting the nodes with short strings in the bottom level, then attaching a random half of the nodes to parent nodes in the next level.

Rope (unit)

A rope may refer to any of several units of measurement initially determined or formed by ropes or knotted cords.

Length

The Greco-Roman schoenus, supposedly based on an Egyptian unit derived from a wound reed measuring rope, may also be given in translation as a "rope". According to Strabo, it varied in length between 30 to 120 stadia (roughly 5 to 20 km) depending on local custom.

The Byzantine equivalent, the schoinion or "little rope", varied between 60 to 72 Greek feet depending upon the location.

The Thai sen of 20 Thai fathoms or 40 m also means and is translated "rope".

The Somerset rope was a former English unit used in drainage and hedging. It was 20 feet (now precisely 6.096 m).

Area

The Romans used the schoenus as an alternate name for the half-jugerum formed by a square with sides of 120 Roman feet.

In Somerset, the rope could also double as a measure of area equivalent to 20 feet by 1 foot. Walls in Somerset were formerly sold "per rope" of 20 sq ft.

Garlic

In medieval English units, the rope of garlic was a set unit of 15 heads of garlic. 15 such ropes made up the "hundred" of garlic.