Text 8. Derrick

Derrick (or Derick) was the name of a London hangman (палач) in about 1600. Given the similarity between a gallows (виселица) and lifting devices in use at that time, it is not hard to see how our present equipment came to bear this name.

In the ANSI Safety Code for Cranes, Derricks, Hoists, Jacks and Slings, a derrick is defined as “an apparatus consisting of a mast or equivalent member held at the end by guys or braces, with or without a boom, for use with a hoisting mechanism and operating ropes.” There is one more, less restrictive definition of a derrick: “a device for raising and lowering loads laterally through use of a hoisting mechanism employing ropes but whose hoisting engine is not an integral part of the machine. This latter definition also provides a simple definition for a crane, which is a derrick with the simple integration of a hoist engine.

The derrick illustrated in Figure below is of the most basic form, it includes a hoisting system, a luffing system, and a strut or boom. It is called a Chicago boom and is used to hoist machinery and equipment onto high buildings, to hoist and place exterior facing panels, and for other purposes. Capacities range from less than 1 ton (900 kg) to at least as high as the 35-ton model. Chicago booms are usually installed by mounting them to building columns. The same arrangement of derrick becomes a guy derrick when it is mounted to a mast and a stiffleg derrick when it is fixed to a frame.

The derrick configuration must be stable in both the vertical and horizontal planes. Vertical stability is ensured by the triangular arrangement of the boom, the topping lift, and the structure on which the derrick is mounted. Lateral stability is provided by guy lines attached to each side of the boom (strut) tip and running back to the structure. The same lines that provide lateral stability are used to swing the boom. This is done by taking up on one guy line while paying out the other, a procedure usually done manually but sometimes by winches or hydraulic or electric devices.

Переведите текст на русский язык. Сформулируйте содержание каждого абзаца в 1-2 предложениях на английском языке.

2. Ответьте на вопросы:

1. What is the distinctive feature of derricks?

2. How can we define a crane using the definition of a derrick?

3. In what directions can a derrick move loads?

4. How is the lateral stability ensured in guy derricks and in stiffleg derricks?

5. What purpose does the derrick mast serve?

3. Исправьте ошибки в переводе (преобразуйте предложение в правильное литературное):

1. There are various types of derrick based on how the tower or mast is set up and the use of boom:
Существуют различные типы вышке, основанные на том, как башня или мачта устанавливается и использование стрелы:

2. In an A-frame derrick, the tower is set up from two masts with their bottom ends spread from each other and their top ends joint together. There are crossbars to connect the two poles, forming a letter " A" shape tower. The tower is ground-anchored to provide support. A boom is hinged from the lowest cross bar and extends outward and upward. The top end of the boom is connected to a pulley system which is connected to the top of the tower. Manipulating the pulley system will allow the boom to change the angle against the tower. There is another pulley system to connect to the top of the boom for load lifting. When an A-frame derrick is used in a vessel, it is called floating A-frame derrick.
В А-образная рама вышка, башня устанавливается из двух мачты с их нижними концами распространение друг от друга, а их верхние концы сустава вместе. Есть поперечины, чтобы соединить две мачты, образуя письмо башни формы " А". Башня размалывают на якорь, чтобы оказать поддержку. Бум шарнирно соединен с нижней поперечиной и простирается наружу и вверх. Верхний конец стрелы соединен с системой шкивов, которая соединена с верхней части башни. Манипулирование систему шкива позволит стрелы, чтобы изменить угол по отношению к башне. Существует еще одна система шкива для подключения к верхней части стрелы для подъема груза. Когда А-репером деррик используется в сосуд, она называется плавающей А-образная вышка.

3. A Chicago boom derrick is a derrick with a boom which is attached to an external structure. The external upright member of the structure serves as the mast, and the boom is stepped in a fixed socket clamped to the upright. The boom is connected to at least three pulley systems to control the position of the boom. For example, a pulley system is connected to the top of the boom and the higher area of the external structure and two pulley systems near the top of the boom connected on either side of the boom to the external structure. The position of the top of the boom can be controlled by manipulating these pulley systems. The load is lifted from a separate pulley system that is connected to the top of the boom.
Чикагский бум Деррик является Деррик со стрелой, которая прикреплена к внешней структуре. Внешний вертикальный элемент конструкции служит мачты, а стрела шагнула в фиксированном гнездо плотно прижат к вертикально. Штанга соединен, по меньшей мере, трех систем шкивов для управления положением стрелы. Например, Шкив система подключена к верхней части стрелы и большей площади внешней структуры и двух шкивов систем вблизи верхней части стрелы, связанной с каждой стороны штанги к внешней структуре. Положение верхней части стрелы можно управлять посредством манипулирования этими системы шкивов. Груз поднимается от отдельного шкива системы, который подключен к верхней части стрелы.