Read the following word combinations and try to guess their meaning

Lowering a load, manually operated, pneumatically driven, wire rope, lifting hook, to engage the chain, integral-package unit, cost-effective purchasing, moderate use, built-up custom unit, vertical lifting, rated load, high-performance chain.

Read the text about Hoists and complete sentences 1-7 with appropriate words from the text.

Hoists

A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fiber or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook.

The basic hoist has two important characteristics to define it: lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoist and chain hoist have been in common use since the 1800s. However, mass production of an electric hoist did not start until the early 1900s and was first adapted by Germany. A hoist can be built as one integral-package unit, designed for cost-effective purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance. The built-up hoist will be much more expensive, but will also be easier to repair and more durable. Package units were once regarded as being designed for light to moderate usage, but since the 60s this has changed. Built-up units are designed for heavy to severe service, but over the years that market has decreased in size since the advent of the more durable packaged hoist. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or NASA would use a built-up unit to meet durability, performance, and repairability requirements.

Common small portable hoists are of two main types, the chain hoist or chain block and the wire rope or cable type. Chain hoists may have a lever to actuate the hoist or have a loop of operating chain that one pulls through the block (known traditionally as a chain fall) which then activates the block to take up the main lifting chain.

A hand powered hoist with a ratchet wheel is known as a "ratchet lever hoist" or, colloquially, a "come-along". The original hoist of this type was developed by Abraham Maasdam of Deep Creek, Colorado about 1919, and later commercialized by his son, Felber Maasdam, about 1946.

Ratchet lever hoists have the advantage that they can usually be operated in any orientation, for pulling, lifting or binding. Chain block type hoists are usually suitable only for vertical lifting.

For a given rated load wire rope is lighter in weight per unit length but overall length is limited by the drum diameter that the cable must be wound onto. The lift chain of a chain hoist is far larger than the lift wheel over which chain may function. Therefore, a high-performance chain hoist may be of significantly smaller physical size than a wire rope hoist rated at the same working load.

Also known as a Man-Lift, Buckhoist, temporary elevator, builder hoist, passenger hoist or construction elevator, this type of hoist is commonly used on large scale construction projects, such as high-rise buildings or major hospitals. There are many other uses for the construction elevator. Many other industries use the buckhoist for full-time operations, the purpose being to carry personnel, materials, and equipment quickly between the ground and higher floors, or between floors in the middle of a structure. There are three types: Utility to move material, personnel to move personnel, and dual-rated, which can do both.

The construction hoist is made up of either one or two cars (cages) which travel vertically along stacked mast tower sections. The mast sections are attached to the structure or building every 25 feet (7.62 m) for added stability. For precisely controlled travel along the mast sections, modern construction hoists use a motorized rack-and-pinion system that climbs the mast sections at various speeds.

In underground mining a hoist or winder is used to raise and lower conveyances within the mine shaft. Human, animal and water power were used to power the mine hoists documented in Agricola's De Re Metallica, published in 1556. Stationary steam engines were commonly used to power mine hoists through the 19th century and into the 20th, as at the Quincy Mine, where a 4-cylinder cross-compound Corliss engine was used. Modern hoists are powered using electric motors, historically with direct current drives utilizing solid-state converters (thyristors); however, modern large hoists use alternating current drives that are variable-frequency controlled. There are three principal types of hoists used in mining applications, Drum Hoists, Friction (or Koepe) hoists and Blair multi-rope hoists.

1. Buckhoist is commonly used on large scale construction projects, such as _______ buildings or major hospitals.

2. Modern hoists are _______ using electric motors.

3. Chain block type hoists are usually suitable only for _______ lifting.

4. In underground mining a _______ is used to raise and lower conveyances within the mine shaft.

5. A hoist is a device used for _______ or lowering a load by means of a drum.

6. NASA would use a built-up unit to meet durability, performance, and _______ requirements.

7. The load is attached to the hoist by means of a lifting _______.