What is meant by “ Plant Hire”?
Лекции.ИНФО


What is meant by “ Plant Hire”?



Задание 1-1

Просмотрите текст, определите, на какие смысловые части можно его разделить, и озаглавьте каждую часть.

Задание 1-2

1)Прочтите описание одного из видов экскаваторов и заполните следующую таблицу.

Тип машины Применение Грунт Преимущества и недостатки
       

 

2) Ответьте на следующие вопросы:

1.What are shovels (hoes, draglines...) designed for?

2.What are the basic parts of the machine?

3. How is digging accomplished?

4. What is the employment of the shovel (the hoe, the dragline)?

5. What do the following terms mean : digging face, ramping down?

6. What methods of positioning the machine while digging are used?

7.Enumerate the machines you read about and their use.

SHOVELS

The shovel, or crane-shovel equipped with a shovel attachment, was the original member of the crane-shovel family.

The shovel front end includes the shovel boom, dipper stick, dipper (or bucket), shipper shaft, and necessary wire ropes or hydraulic cylinder system.

The shovel digs by a combination of crowd and hoist action illustrated in Figure 2. The dipper stick is crowded or retracted by the action of the shipper shaft. After the bucket is filled, the boom is swung laterally to the unloading point and the load dumped by releasing the bucket latch. The ability to force the bucket into the material being dug using crowd action enables the shovel to big the toughest soils and even soft or fractured rock.

Although the shovel can dig either below or above ground level, it is most efficient when digging from ground level up to about the elevation of the shipper shaft. Other front-end attachments (such as the hoe or dragline) are better suited than the shovel for excavating below ground level. Since the shovel starts its most efficient digging cycle at ground level, it can form its own roadway as it advances - an important advantage. The shovel is also able to shape the sides of its cut end to dress slopes when required. Materiel dug by the shovel can be loaded into haul units, dumped onto spoil banks, or side cast into low areas.

Figure 2. Shovel components and its digging action

For efficient digging, the shovel must have a vertical surface to dig against. This surface in known as the digging face. A digging face in easily formed when the material to be excavated exists as a bank or hillside, but when the material to be excavated is initially located below ground level, the shovel must dig a ramp down into the material until a digging face of suitable height is created. This process is known as raping down.

Once a suitable digging face has been obtained. the cut is typically developed by using once of the two basic methods of attack or a variation of these. The frontal approach allows the most effective digging position of the shovel to be used since the shovel can exert the greatest digging force in this position. This is an important consideration in digging hard materials. Trucks can be loaded on either or both aides of the shovel with a maximum swing usually no greater than 90 gr. The parallel approach permits fast move-up of the shovel as the digging face advances and it permits a good traffic flow for hauling unite. The parallel approach is usually used whenever space is limited and for highway outs.

A crane -shove1 that 1e equipped with a hoe front-end attachment is called a hoe. However, it 1e frequently reffered to as a backhoe and sometimes as a trench hoe, drag shovel, draghoe , or pull shovel. The components of a hydraulic hoe are illustrated in Figure 3. Hydraulic machines built primarily for use as hoes are frequently called hydraulic excavators.

Digging is accomplished by pulling the dipper toward the machine. When the dipper is filled, the boom is raised and swung to the unloading position. The load is then dumped by swinging the dipper up end away from the machine.

In hydraulic hoes the boom and dipper arms are raised and

lowered by hydraulic cylinders. In addition, the dipper is pivoted at the end of the dipper arm and controlled by another hydraulic cylinder so that a wrist-like action is provided.

Figure 3. Hydraulic hoe components

Dippers are available in a range of size and widths for each machine size. Dipper width is often more important in trenching work than in dipper capacity. Different size side cutters are also available to change the dipper's cutting width.

Since the hoe combines positive digging action with rigid control of the bucket, it is able to dig accurately in all but the hardest materials. The hoe's major advantages are its digging power and its ability to dig below machine level.

Although the hoe and dragline can both dig below ground level, they ar not really competitors. The draglime has a much wider digging and dumping range, but it possesses less power and accuracy in. its digging.

The hoe is especially well-suited for excavating. Trenches because of the characteristics motioned above.

Another major application or the hoe is found in making basement excavations and similar precise excavations. Other useful application of the hoe include cleaning roadside ditches and sloping or grading embankments.

In selecting the proper hoe to be used in a particular application, digging ranges and clearances are important considerations. These include the following :

1. Maximum depth required.

2. Largest working radius required for’ digging or dumping.

3. Maximum dumping height required.

4. Clearance required for carrier, superstructure, and boom. This includes surrounding buildings or obstacles as well as width of out required to provide machine clearance in a multi-layer excavation.

DRAGLINES

The crane-shovel that is equipped with a crane boom, dragline bucket end accessories, fairlead assembly, and necessary cables is known as a dragline. The dragline is an extremely versatile machine capable of digging from above machine level to far below machine level. It can handle material ranging from soft to medium hard. Probably the dragline’s greatest advantage over other members of the crane- shovel family is its long reach for both digging and dumping. It also has a high cycle speed that is surpassed only by the shovel.

The hoist cable is used to raise and lower the bucket. Digging is accomplished as the drag cable pulls the bucket through the material to be excavated. The dump cable, through tension on the drag cable, serves, to hold up the front of the bucket so that material will not spill where the bucket is being hoisted. Dumping is accomplished by releasing the tension on the drag cable while the bucket is supported by the hoist cable. The length of the dump cable is adjusted so that easy dumping is obtained with minimum spillage for the material being excavated. The fairlead assembly is used to guide the drag cable onto the drum during digging operations.

Although the dragline can dig at a level above machine elevation, it is most effective in digging at or below machine level. The dragline does not have the positive digging at or below machine level. The dragline does not have the positive digging force of the shovel or hoe but must depend on the weight of the bucket and the angle of attachment of the drag chain to the bucket to provide its digging action.

The two basic methods of positioning the dragline at the digging face are illustrated in Figure 4.

For digging trenches and other relatively narrow excavations, the ‘ in-line approach’ or ‘straight-away digging’ is usually used. In this approach the machine straddles the center line of the excavation and dumps on one or both sides of the excavation. The machine moves along the center of the excavation line and way from the digging face as excavation progresses. In the parallel approach the machine moves parallel to the digging face as work progresses. The parallel approach is used for wide excavations and for more effective sloping of an embankment.

Раздел 11

Задание 2-1

Ниже на русском и английском языках дано описание 5 экскаваторов отечественного производства а) правильно соотнесите описание каждого экскаватора, б) назовите тип экскаватора, в) выпишите в свой словарь термины, встречающиеся в описании экскаваторов, и их перевод.

1. HYDRAULIC EXCAVATOR

2. TUNNELLING EXCAVATOR

3. WHEEL TRENCHER

4. CHAIN TRENCHER

5. OPEN-MINE EXCAVATOR

1. Intended for digging blasted heavy rook and loading it to transport vehicles or discharging to dump. Employed in open mining in the ferrous and non-ferrous metallurgy, building materials industry and coal mining.

Modern design and high-grade materials used in excavator manufacture ensure its dependable operation at temperatures from +45 to -40°C.

Excavator front-end equipment consists of a face shovel with a hinged-joint boom, a round section single – girder bucket arm, and rope crowd mechanism.

All excavators mechanisms have separate electric drives while each bogie comprises its own travel drive. The excavator has a number of auxiliary devices and mechanisms facilitating its repairs and assembly.

2. Intended to perform the complete cycle of building earthen structures, including the digging of trenches, pits and gutters, their trimming or levelling and slope levelling to the specified angle of incline.

Among the special design features of the excavator is its ability to carry cut soil levelling and surface finishing, with the bucket bottom rested on the ground, and the employment of a servo system which controls bucket angle in operation.

The interchangeable front-end equipment includes a digging and levelling bucket, levelling blade, monoblock boom, extended bucket arm, dragshovel with the buckets of various capacity and application, clamshells and ripper.

3. Designed to dig trenches in the soil of up to the 4th hardness class included, and in the frozen soil with a freezing depth up to 1 m. The machine is suitable for digging trenches with slopes in the upper part in the unfrozen soil of up to the 2d hardness class included, and without slopes in the soil of the 4th hardness class or in frozen soil.

In addition to the travel motion hydraulic system the trencher comprises e separate hydraulic system for varying the height of digging wheel installation and the outreach of the discharge conveyor.

4.Intended to dig trenches of a rectangular cross- section in the soil of the 1st to 3rd hardness classes, with the exception or sticky and wet soil, with the purpose of laying communication and electric supply cables and pipelines of various application. Also suitable for trench backfilling and various small-scale earth-moving jobs in the soil of the 1st and 2nd hardness classes, using the bulldozer blade.

The trencher working tool is retained in the desired position by means of on automatic servo.

5. Intended for loading blasted rock (maximum lamp size 500 mm) to self-propelled transport vehicles in the driving of underground workings with a cross-section of 35 to 70 m^2.

Provision is made for equipping the excavator with a more powerful electric motor, and for connecting the pneumatic system to an external source of compressed air supply.

1.Предназначен для выполнения полного цикла строительства земляных сооружений: рытья траншей, котлованов, кюветов, зачистки или их планировки, а так же для планировки откосов с заданным уклоном.

Отличительные особенности экскаватора- копание с опиранием на днище ковша при планировочных или финишных работах, а так же наличие следящей системы управления угловым положение ковша.

Сменное рабочее оборудование

- экскавационно -планировочный ковш, планировочный отвал, моноблочная стрела, удлиненная рукоять, обратная лопата с ковшами различной вместимости и назначения, грейферами и рыхлителями.

2. Предназначен для рытья траншей в грунтах до 1У категории включительно и в мерзлых грунтах с глубиной промерзания до 1 м. В талых грунтах до 3 категории включительно. Траншеи можно рыть с откосами в верхней части, в грунтах 1У категории и в мерзлых грунтах – без откосов.

Кроме гидросистемы привода хода экскаватор оснащен гидросистемой , обеспечивающей изменение высоты подвески рабочего органа и вылета транспортера.

3. Предназначен для погрузки взорванной скальной пароды ( с размером кусков не более 500мм) в самоходные транспортные средства при проходе подземных выработок сечением от 35 до 70 м^2.

На экскаваторе предусмотрена возможность установки более мощного двигателя и присоединения пневмосистемы к внешней сети сжатого воздуха.

4. Предназначен для рытья траншей прямоугольного сечения в грунтах 1-3 категорий, за исключением вязких влажных грунтов, под кабельные линии связи, электропередачи и трубопроводы земляных работ малого объёма в грунтах 1 и 2 категорий с помощью бульдозерного отвала.

На машине применена автоматическая система слежения за задним положением рабочего органа.

5. Предназначен для разработки и погрузки в транспортные средства или в отвал предварительно взорванных тяжелых скальных пород. Применяются при открытых горных работах в черной и цветной металлургии, промышленности строительных материалов, угольной промышленности.

Современная конструкция и высокопрочные материалы, применяемые в экскаваторе, обеспечивают его надежную работу при температуре окружающего воздуха от +45 до -40 С.

Рабочее оборудование экскаватора- прямая лопата с шарнирно- сочлененной стрелой, однобалочной рукоятью круглого сечения и канатным механизмом напора.

Все механизмы экскаватора снабжены индивидуальными электроприводами.

Каждая ходовая тележка имеет индивидуальный привод механизма передвижения. Экскаватор имеет ряд вспомогательных устройств и механизмов, облегчающих выполнение ремонтных и монтажных работ.

1. Ходовое устройство

2. Поворотная платформа

3. Рабочее оборудование

4. Силовая установка

5. Гидросистема

6. Система управления

Задание 2-2

В правой колонке найдите перевод каждого термина. Проверьте друг друга, как вы запомнили термины.

I. 1. Electric motor power 1. ширина

2. hydraulic system pressure 2. вместимость ковша

3 .bucket capacity 3. Длина планируемого участка

4. length of leveled ground 4. Мощность электродвигателей

5. maximum digging radius 5. Габаритные размеры

6. maximum discharge height 6. Давление в гидросистеме

7. maximum digging depth 7.наибольший радиус копания

8. overall diamensions 8. Наибольшая глубина копания

9 .bucket width 9. Насосная силовая установка

10.power pumping plant 10. Наибольшая высота выгрузки

11. скорость движения

II.1. capacity of face shovel bucket 1.насос с переменной подачей

2. dragshovel bucket capacity 2. Погрузочное оборудование

3. variable-capacity pump 3. Сменное рабочее оборудование

4. constant- capacity pump 4. Вместимость ковша обратной

5. hydraulic plant power лопаты

6.power pumping plant 5. Насос с постоянной подачей

7.hydraulic system maintenance 6.действие силовой гидроустановки

8. hydraulic system operation 7. Вместимость ковша прямой лопаты

9. interchangeable equipment 8. Насосная силовая установка

10. load- handling attachments 9.мощность силовой гидравлической установки

10. самоходные транспортные средства

11.обслуживание силовой гидравлической установки

 

II

III.1. self-propelled transport vehicles 1.оборудование захватно- клещевого типа

2. profiling and trimming buckets 2. рыхлитель

3.crowd-action clamshell 3.профильный и зачистной ковш

4. hydraulic hammer 4. Увеличенное тяговое усилие

5. lifting tongs 5.взорванная скальная порода

6. ripper 6.напорный грейфер

7. blasted rock 7.самоходные транспортные средства

8. increased pull 8. Наибольшая высота выгрузки

9. maximum discharge height 9.гидромолот

10. hydraulic system pressure 10.давление в гидросистеме

11.наибольшая высота копания

IV.1. to dig blasted heavy rock 1.выполнять полный цикл строительства

2. to discharge to dump земляных сооружений

3. to employ in open mining 2.управлять( следить за) угловым

4. to ensure dependable operation положением ковша

5. to facilitate repair and assembly 3.разрабатывать взорванные тяжелые

6. to carry out soil levelling and surface скальные породы

finishing 4.принудительно заглублять рабочий

7. to control bucket angle орган в грунт

8. to perform the complete cycle or 5.разгружать в отвал

building earthen structures 6.содержать индивидуальный привод

9. to comprise one's own travel механизма передвижения

motion drive 7.применять при открытых горных работах

10. to force toe digging buckets into soil 8.обеспечивать надежную работу

9.выполнять планировочные и финишные

работы

10.облегчать выполнение ремонтных и

монтажных работ

 

V. 1. rope crowd mechanism 1.вспомогательные устройства

2 . auxiliary devices 2.однобалочная рукоять ковша

3. hinged-joint boom 3. Талый грунт

4. single-girder bucket arm 4.канатный механизм напора

5. high-grade material 5.глубина промерзания

6 . rectangular cross-section 6.шарнирно- сочлененная стрела

7.Removal of soil blocks 7.прямоугольное сечение

8.Outreach of discharge conveyor 8.высокопрочные материалы

9.Unfrozen soil 9.вылет транспортера

10.Freezing depth 10.выемка целиков грунта

11.габаритные размеры

ЗАДАНИЕ 2-3

Просмотрите текст и перечислите машины, описанные в нем. Переведите текст-время 15 мин (каждый студент переводит один раздел).

LOADERS AND OTHER EXCAVATORS

1.In addition to the members of the crane-shovel family, there are a number of other pieces of equipment suitable for excavating and loading haul units. One of the items of equipment most frequently used for such purposes is called a wheel loader. The wheel loader is a wheeled version of e machine also called e scoop loader, front-end loader, bucket loader, or tractor-shovel. Track-type loaders are also available.

Many of these machines, particularly the track-type loader, closely resemble the tractor, The factors effecting speed and usable power (traction, rolling and grade resistance, etc) are the same for loaders as they are for tractors.

Loader buckets are available in a wide range of sites. Two types of buckets are usually available: a solid or scoop bucket and a multi-segment bucket. The multi-segment bucket has more flexibility than the solid bucket since it can be used like a clamshell, dozer, or scraper as well as a scoop shovel.

2. Besides the members of the crane-shovel family and front end loaders, there are several other types of equipment used for excavating and loading. These include elevating loaders, bucket wheel excavators, and trenching machines. All of these machines combine some type of cutter with a conveyor belt for moving excavated material to hauling units. Dual belts are frequently used with these machines so that haul units may be loaded on alternate sides of the machine, thus eliminating the time lost in spotting haul unites.

3.Elevating loaders combine a scoop-type cutting head with a belt loader. Usually, the machine is towed by one or more earthmoving tractors, although the loader may be equipped with its own propelling units. Such machines are capable of excavating and loading several thousand bank cubic yards of material per hour under favorable conditions.

Bucket wheel or continous -wheel excavators combine large bucket wheel-type cutters with a belt loading system. These machines are usually self-propelled and designed for high production rates. They, like the elevating loader, are best suited to large. relatively flat excavation areas. These machines may yield low excavating and loading unit costs on large earthmoving project such as dam construction, mining, etc.

4. Trenching machines were developed to dig trenches for cables and pipelines faster and more economically then excavators like the hoe or the dragline. Major types of trenching machine include the continuous chain trencher, the ladder-type trencher, and the wheel-type trencher.

Continuous-chain trenchers use a series of digging scoops spaced along a continuous, power-driven chain to provide digging action. They are used for relatively shallow, narrow trenches and are available in very small sizes for laying power and communications lines. They are usually limited in digging depth to 6 ft or so.

Ladder-type trenchers operate somewhat like continuous-chain trenchers but are larger and heavier. They are available in a wide range of bucket widths and can excavate to a depth of 30 ft or more. Thus, they have the greatest depth capability of any trencher.

Wheel -type trenchers use a bucket wheel-type of excavator for digging action. They are also available in a range of bucket widths but are limited in digging depths to around 10 ft.

ЗАДАНИЕ 2-4

Прочтите текст, осветите следующие положения:

1)классификация экскаваторов по их массе,

2)область применения,

3)факторы, определяющие выбор той или иной машины.

HYDRAULIC EXCAVATORS: INCREASES IN EFFICIENCY

By Margaret Briggs

Just as the gradual introduction some 15 to 20 years ago of the hydraulic excavator marked a major step forward in performance and precise control compared with rope operated machines, so more recent developments in the hydraulic systems have achieved a substantial increase in efficiency.

What kind of application is a hydraulic excavator used for? This varies very much according to machine size. The majority of hydraulic excavators may be divided into categories: the first, covering machines of 11 to 14 tonnes. Category 2 may be considered as the 15 to 17 t excavators and the third, 17 to 23 t. This does not cover the very small units or the very big, the latter often face shovels.

The category 1 machine is capable of doing almost any job but it is too small where bulk shifting and high outputs are involved.

Highway maintenance often involves the use of an excavator. Digging a trench, loading into dump trucks, handling.

Hymac 890 featuring a medium pressure hydraulic system with three variable volume piston pumps and summated power control pipe and back filling are common excavator tasks. Excavator-mounted concrete breakers are highly efficient. A category 1 excavator must be versatile and the range of attachments available may be important. The time it takes to exchange buckets or couple up other equipment must be considered.

Work involving category 2 or 3 and even larger excavators covers most construction and civil engineering work and, of special importance, pipe laying.

On Jobs such as road construction, there is some indication that excavators and articulated dump trucks are sometimes taking over from scrapers. The excavator can work down to a finish level and the machines can operate in all but the very worst conditions. Excavators can sometimes replace dragline or crawler dozer for the construction of batters alongside roads. Excavators can operate from the roadway.

The precise control of the hydraulic excavator makes 1t very suitable for demolition work. Another area where excavators feature largely is in the scrap industry, utilising grabs, magnets and other attachments. Precise control is again an important asset.

(Highways and Public Works, Journal)

2. Ответьте на следующие вопросы.

1. What advantages does the hydraulic excavator have over rope operated machines?

2. What factor influenced its efficiency increase?

3. What does the excavator application depend on ?

4.What kind of jobs can excavators perform on road construction ?

5. What time has passed since the hydraulic excavator marked its appearance?

ЗАДАНИЕ 2-5

Скажите, какой из двух вариантов русского перевода соответствует оригиналу. Какие элементы предложения искажают его смысл.

It is only 35 km across the English Channel but judged by the use of wheeled excavators both here and on the continent, then the gulf is probably more like the size of the Atlantic Ocean.

А) Ширина Да - Манша составляет только 35 км, но, если судить по применению экскаваторов на колесном ходу в Великобритании и на континенте , может показаться, что этот пролив равен по величине Атлантическому океану.

Б) длина Да- Манша равна всего 35 км, но, судя по применению экскаваторов на колесном ходу в обеих странах, можно сказать, что пролив больше Атлантического океана.

РАЗДЕЛ III

ЗАДАНИЕ 3-1

1.Прочтите текст и подготовьте его устный перевод.

2. Отрывок “The excavator-loader, also known as…” кончая словами “..in general appearance to be made” переведите письменно.

3.Подготовьте краткое сообщение по следующему плану:

1) The main features of the excavator-loader.

1) Other names given to the machine.

3) The reason of its rapid acceptance.

A) Technical modifications made to the original design.

EXCAVATOR-LOADERS

by Wilfred Barson. Plant Hire Journal.

The forst excavator-loader in the UK was probably a machine by Witlock Bros, shown at a Public Works Ixhibition in the early 1950 s. This first machine, based on an agricultural tractor, was of the same general configuration as the present-day machines, with a forward mounted loading shovel and a rear mounted backhoe excavator, both powered from the tractor hydraulic circuit.

The excavator- loader, also known variously as backhoe-loader, digger- loader and loader backhoe, is in many ways a unique development in construction equipment , as it fulfils efficiently dual and divergent purposes in a manner unparalleled by any other single machine in the range of earthmovers. It must. be said that it is cumbersome and ungainly in appearance and yet it has won rapidly increasing acceptance, having established itself as one of the few machines of economical working on widely varying sites. Furthermore, integrated design of the tractor and equipment and modern manufacturing techniques have made some styling and improvement in general appearance to be made.

The JD410 , a typical excavator-loader with side shift backhoe equipment

Although originally based on agricultural or industrial tractors, considerable strengthening of the frame and other modifications were often necessary and now, almost without exception, the chassis are specially constructed as part of the over- all design, including many standard parts such as transmissions, wheels and axles and other components used for general economy in manufacture and operation.

The loader equipment is generally similar to that fitted to ordinary wheel loaders of comparable size, while the back-hoe excavator equipment is a complete unit with its own operating controls and can usually be detached from the tractor fairly readily.

ЗАДАНИЕ 3-2

1. Прочтите текст и подготовьте его устный перевод.

2. Отрывок , в котором говорится о применении мини-экскаватора, переведите письменно.

3. Подготовьте краткое сообщение о прочитанной статье по следующему плану:

1. What is a mini excavator?

2. What is the reason of its creation?

3. What jobs does a mini excavator carry out?

4. What are its technical characteristics?

5. What is the application of a dozer blade in the mini excavator?

6. What attachments are used with a mini excavator?

MINI EXCAVATORS

by Wilfred Barson

A mini excavator is considered to be a single bucket backhoe machine up to about 5 tonnes weight, mounted on power driven crawlers or four wheels and having a 360 degree slewing superstructure incorporating the operator's cab.

The mini excavator carries out many of email trenching and general excavating jobs which, a few years ago, would have been done manually by pick and shovel because limited space, difficulty of access and transport costs ruled out the use of a standard size excavator. The mini excavator is a true miniature of the standard excavator excepting that the often cramped working conditions call for some extra movements not always essential on the larger standard machines. Chief among these is offsetting the boom and front end equipment by swinging it about 50 degrees to each side, independently of the main slew, to facilitate digging near to side obstructions; also a hydraulically operated, full width dozer blade for grading, backfilling and levelling when necessary to provide safer standing for the machine. The blade can be used also as a stabilizer or dug into the ground to act as en extra digging brake, particularly useful when working on sloping surfaces.

To enable the mini excavator to handle most phases of the small jobs, a wide range of buckets and other attachments is available and provision is made for operating a hydraulic hammer. There is also a hydraulic power takeoff for hand-held breakers and other tools.

РАЗДЕЛ IУ

ЗАДАНИЕ 4-1.

Прочтите статьи, изложите краткое содержание и ответьте на поставленные к ним вопросы.

What is the story about?

FILM STRESSES SERVICE SAFETY

It took top honors at the international industrial Film Festical in Copenhagen. But Caterpillar‘s “Shake Hands With Danger” is also a motion picture with a message, as they say.

The message is simple: Follow safety rules when servicing and maintaining construction equipment - or pay the consequences.

According to Caterpillar, the film is aimed at the “old pro” who thinks he knows all the safety rules. To get the point across, special effects and dramatic portrayals reenact accident case histories.

The recent award brings to seven the number of major prizes won by Caterpillar on safety.

 

The 16mm color film in available for local showing from Caterpillar dealers. Companion pieces include a 32-page service-man’s safety booklet, stereo cassettes of the theme music, and toolbox warning decals for handouts.

(Engineering and Contract Record; Construction Equipment)

ЗАДАНИЕ 4-2

Напишите аннотацию и реферат данной статьи.

 

Задание 1-1

Просмотрите текст, определите, на какие смысловые части можно его разделить, и озаглавьте каждую часть.

Задание 1-2

1)Прочтите описание одного из видов экскаваторов и заполните следующую таблицу.

Тип машины Применение Грунт Преимущества и недостатки
       

 

2) Ответьте на следующие вопросы:

1.What are shovels (hoes, draglines...) designed for?

2.What are the basic parts of the machine?

3. How is digging accomplished?

4. What is the employment of the shovel (the hoe, the dragline)?

5. What do the following terms mean : digging face, ramping down?

6. What methods of positioning the machine while digging are used?

7.Enumerate the machines you read about and their use.

SHOVELS

The shovel, or crane-shovel equipped with a shovel attachment, was the original member of the crane-shovel family.

The shovel front end includes the shovel boom, dipper stick, dipper (or bucket), shipper shaft, and necessary wire ropes or hydraulic cylinder system.

The shovel digs by a combination of crowd and hoist action illustrated in Figure 2. The dipper stick is crowded or retracted by the action of the shipper shaft. After the bucket is filled, the boom is swung laterally to the unloading point and the load dumped by releasing the bucket latch. The ability to force the bucket into the material being dug using crowd action enables the shovel to big the toughest soils and even soft or fractured rock.

Although the shovel can dig either below or above ground level, it is most efficient when digging from ground level up to about the elevation of the shipper shaft. Other front-end attachments (such as the hoe or dragline) are better suited than the shovel for excavating below ground level. Since the shovel starts its most efficient digging cycle at ground level, it can form its own roadway as it advances - an important advantage. The shovel is also able to shape the sides of its cut end to dress slopes when required. Materiel dug by the shovel can be loaded into haul units, dumped onto spoil banks, or side cast into low areas.

Figure 2. Shovel components and its digging action

For efficient digging, the shovel must have a vertical surface to dig against. This surface in known as the digging face. A digging face in easily formed when the material to be excavated exists as a bank or hillside, but when the material to be excavated is initially located below ground level, the shovel must dig a ramp down into the material until a digging face of suitable height is created. This process is known as raping down.

Once a suitable digging face has been obtained. the cut is typically developed by using once of the two basic methods of attack or a variation of these. The frontal approach allows the most effective digging position of the shovel to be used since the shovel can exert the greatest digging force in this position. This is an important consideration in digging hard materials. Trucks can be loaded on either or both aides of the shovel with a maximum swing usually no greater than 90 gr. The parallel approach permits fast move-up of the shovel as the digging face advances and it permits a good traffic flow for hauling unite. The parallel approach is usually used whenever space is limited and for highway outs.

A crane -shove1 that 1e equipped with a hoe front-end attachment is called a hoe. However, it 1e frequently reffered to as a backhoe and sometimes as a trench hoe, drag shovel, draghoe , or pull shovel. The components of a hydraulic hoe are illustrated in Figure 3. Hydraulic machines built primarily for use as hoes are frequently called hydraulic excavators.

Digging is accomplished by pulling the dipper toward the machine. When the dipper is filled, the boom is raised and swung to the unloading position. The load is then dumped by swinging the dipper up end away from the machine.

In hydraulic hoes the boom and dipper arms are raised and

lowered by hydraulic cylinders. In addition, the dipper is pivoted at the end of the dipper arm and controlled by another hydraulic cylinder so that a wrist-like action is provided.

Figure 3. Hydraulic hoe components

Dippers are available in a range of size and widths for each machine size. Dipper width is often more important in trenching work than in dipper capacity. Different size side cutters are also available to change the dipper's cutting width.

Since the hoe combines positive digging action with rigid control of the bucket, it is able to dig accurately in all but the hardest materials. The hoe's major advantages are its digging power and its ability to dig below machine level.

Although the hoe and dragline can both dig below ground level, they ar not really competitors. The draglime has a much wider digging and dumping range, but it possesses less power and accuracy in. its digging.

The hoe is especially well-suited for excavating. Trenches because of the characteristics motioned above.

Another major application or the hoe is found in making basement excavations and similar precise excavations. Other useful application of the hoe include cleaning roadside ditches and sloping or grading embankments.

In selecting the proper hoe to be used in a particular application, digging ranges and clearances are important considerations. These include the following :

1. Maximum depth required.

2. Largest working radius required for’ digging or dumping.

3. Maximum dumping height required.

4. Clearance required for carrier, superstructure, and boom. This includes surrounding buildings or obstacles as well as width of out required to provide machine clearance in a multi-layer excavation.

DRAGLINES

The crane-shovel that is equipped with a crane boom, dragline bucket end accessories, fairlead assembly, and necessary cables is known as a dragline. The dragline is an extremely versatile machine capable of digging from above machine level to far below machine level. It can handle material ranging from soft to medium hard. Probably the dragline’s greatest advantage over other members of the crane- shovel family is its long reach for both digging and dumping. It also has a high cycle speed that is surpassed only by the shovel.

The hoist cable is used to raise and lower the bucket. Digging is accomplished as the drag cable pulls the bucket through the material to be excavated. The dump cable, through tension on the drag cable, serves, to hold up the front of the bucket so that material will not spill where the bucket is being hoisted. Dumping is accomplished by releasing the tension on the drag cable while the bucket is supported by the hoist cable. The length of the dump cable is adjusted so that easy dumping is obtained with minimum spillage for the material being excavated. The fairlead assembly is used to guide the drag cable onto the drum during digging operations.

Although the dragline can dig at a level above machine elevation, it is most effective in digging at or below machine level. The dragline does not have the positive digging at or below machine level. The dragline does not have the positive digging force of the shovel or hoe but must depend on the weight of the bucket and the angle of attachment of the drag chain to the bucket to provide its digging action.

The two basic methods of positioning the dragline at the digging face are illustrated in Figure 4.

For digging trenches and other relatively narrow excavations, the ‘ in-line approach’ or ‘straight-away digging’ is usually used. In this approach the machine straddles the center line of the excavation and dumps on one or both sides of the excavation. The machine moves along the center of the excavation line and way from the digging face as excavation progresses. In the parallel approach the machine moves parallel to the digging face as work progresses. The parallel approach is used for wide excavations and for more effective sloping of an embankment.

Раздел 11

Задание 2-1

Ниже на русском и английском языках дано описание 5 экскаваторов отечественного производства а) правильно соотнесите описание каждого экскаватора, б) назовите тип экскаватора, в) выпишите в свой словарь термины, встречающиеся в описании экскаваторов, и их перевод.

1. HYDRAULIC EXCAVATOR

2. TUNNELLING EXCAVATOR

3. WHEEL TRENCHER

4. CHAIN TRENCHER

5. OPEN-MINE EXCAVATOR

1. Intended for digging blasted heavy rook and loading it to transport vehicles or discharging to dump. Employed in open mining in the ferrous and non-ferrous metallurgy, building materials industry and coal mining.

Modern design and high-grade materials used in excavator manufacture ensure its dependable operation at temperatures from +45 to -40°C.

Excavator front-end equipment consists of a face shovel with a hinged-joint boom, a round section single – girder bucket arm, and rope crowd mechanism.

All excavators mechanisms have separate electric drives while each bogie comprises its own travel drive. The excavator has a number of auxiliary devices and mechanisms facilitating its repairs and assembly.

2. Intended to perform the complete cycle of building earthen structures, including the digging of trenches, pits and gutters, their trimming or levelling and slope levelling to the specified angle of incline.

Among the special design features of the excavator is its ability to carry cut soil levelling and surface finishing, with the bucket bottom rested on the ground, and the employment of a servo system which controls bucket angle in operation.

The interchangeable front-end equipment includes a digging and levelling bucket, levelling blade, monoblock boom, extended bucket arm, dragshovel with the buckets of various capacity and application, clamshells and ripper.

3. Designed to dig trenches in the soil of up to the 4th hardness class included, and in the frozen soil with a freezing depth up to 1 m. The machine is suitable for digging trenches with slopes in the upper part in the unfrozen soil of up to the 2d hardness class included, and without slopes in the soil of the 4th hardness class or in frozen soil.

In addition to the travel motion hydraulic system the trencher comprises e separate hydraulic system for varying the height of digging wheel installation and the outreach of the discharge conveyor.

4.Intended to dig trenches of a rectangular cross- section in the soil of the 1st to 3rd hardness classes, with the exception or sticky and wet soil, with the purpose of laying communication and electric supply cables and pipelines of various application. Also suitable for trench backfilling and various small-scale earth-moving jobs in the soil of the 1st and 2nd hardness classes, using the bulldozer blade.

The trencher working tool is retained in the desired position by means of on automatic servo.

5. Intended for loading blasted rock (maximum lamp size 500 mm) to self-propelled transport vehicles in the driving of underground workings with a cross-section of 35 to 70 m^2.

Provision is made for equipping the excavator with a more powerful electric motor, and for connecting the pneumatic system to an external source of compressed air supply.

1.Предназначен для выполнения полного цикла строительства земляных сооружений: рытья траншей, котлованов, кюветов, зачистки или их планировки, а так же для планировки откосов с заданным уклоном.

Отличительные особенности экскаватора- копание с опиранием на днище ковша при планировочных или финишных работах, а так же наличие следящей системы управления угловым положение ковша.

Сменное рабочее оборудование

- экскавационно -планировочный ковш, планировочный отвал, моноблочная стрела, удлиненная рукоять, обратная лопата с ковшами различной вместимости и назначения, грейферами и рыхлителями.

2. Предназначен для рытья траншей в грунтах до 1У категории включительно и в мерзлых грунтах с глубиной промерзания до 1 м. В талых грунтах до 3 категории включительно. Траншеи можно рыть с откосами в верхней части, в грунтах 1У категории и в мерзлых грунтах – без откосов.

Кроме гидросистемы привода хода экскаватор оснащен гидросистемой , обеспечивающей изменение высоты подвески рабочего органа и вылета транспортера.

3. Предназначен для погрузки взорванной скальной пароды ( с размером кусков не более 500мм) в самоходные транспортные средства при проходе подземных выработок сечением от 35 до 70 м^2.

На экскаваторе предусмотрена возможность установки более мощного двигателя и присоединения пневмосистемы к внешней сети сжатого воздуха.

4. Предназначен для рытья траншей прямоугольного сечения в грунтах 1-3 категорий, за исключением вязких влажных грунтов, под кабельные линии связи, электропередачи и трубопроводы земляных работ малого объёма в грунтах 1 и 2 категорий с помощью бульдозерного отвала.

На машине применена автоматическая система слежения за задним положением рабочего органа.

5. Предназначен для разработки и погрузки в транспортные средства или в отвал предварительно взорванных тяжелых скальных пород. Применяются при открытых горных работах в черной и цветной металлургии, промышленности строительных материалов, угольной промышленности.

Современная конструкция и высокопрочные материалы, применяемые в экскаваторе, обеспечивают его надежную работу при температуре окружающего воздуха от +45 до -40 С.

Рабочее оборудование экскаватора- прямая лопата с шарнирно- сочлененной стрелой, однобалочной рукоятью круглого сечения и канатным механизмом напора.

Все механизмы экскаватора снабжены индивидуальными электроприводами.

Каждая ходовая тележка имеет индивидуальный привод механизма передвижения. Экскаватор имеет ряд вспомогательных устройств и механизмов, облегчающих выполнение ремонтных и монтажных работ.

1. Ходовое устройство

2. Поворотная платформа

3. Рабочее оборудование

4. Силовая установка

5. Гидросистема

6. Система управления

Задание 2-2

В правой колонке найдите перевод каждого термина. Проверьте друг друга, как вы запомнили термины.

I. 1. Electric motor power 1. ширина

2. hydraulic system pressure 2. вместимость ковша

3 .bucket capacity 3. Длина планируемого участка

4. length of leveled ground 4. Мощность электродвигателей

5. maximum digging radius 5. Габаритные размеры

6. maximum discharge height 6. Давление в гидросистеме

7. maximum digging depth 7.наибольший радиус копания

8. overall diamensions 8. Наибольшая глубина копания

9 .bucket width 9. Насосная силовая установка

10.power pumping plant 10. Наибольшая высота выгрузки

11. скорость движения

II.1. capacity of face shovel bucket 1.насос с переменной подачей

2. dragshovel bucket capacity 2. Погрузочное оборудование

3. variable-capacity pump 3. Сменное рабочее оборудование

4. constant- capacity pump 4. Вместимость ковша обратной

5. hydraulic plant power лопаты

6.power pumping plant 5. Насос с постоянной подачей

7.hydraulic system maintenance 6.действие силовой гидроустановки

8. hydraulic system operation 7. Вместимость ковша прямой лопаты

9. interchangeable equipment 8. Насосная силовая установка

10. load- handling attachments 9.мощность силовой гидравлической установки

10. самоходные транспортные средства

11.обслуживание силовой гидравлической установки

 

II

III.1. self-propelled transport vehicles 1.оборудование захватно- клещевого типа

2. profiling and trimming buckets 2. рыхлитель

3.crowd-action clamshell 3.профильный и зачистной ковш

4. hydraulic hammer 4. Увеличенное тяговое усилие

5. lifting tongs 5.взорванная скальная порода

6. ripper 6.напорный грейфер

7. blasted rock 7.самоходные транспортные средства

8. increased pull 8. Наибольшая высота выгрузки

9. maximum discharge height 9.гидромолот

10. hydraulic system pressure 10.давление в гидросистеме

11.наибольшая высота копания

IV.1. to dig blasted heavy rock 1.выполнять полный цикл строительства

2. to discharge to dump земляных сооружений

3. to employ in open mining 2.управлять( следить за) угловым

4. to ensure dependable operation положением ковша

5. to facilitate repair and assembly 3.разрабатывать взорванные тяжелые

6. to carry out soil levelling and surface скальные породы

finishing 4.принудительно заглублять рабочий

7. to control bucket angle орган в грунт

8. to perform the complete cycle or 5.разгружать в отвал

building earthen structures 6.содержать индивидуальный привод

9. to comprise one's own travel механизма передвижения

motion drive 7.применять при открытых горных работах

10. to force toe digging buckets into soil 8.обеспечивать надежную работу

9.выполнять планировочные и финишные

работы

10.облегчать выполнение ремонтных и

монтажных работ

 

V. 1. rope crowd mechanism 1.вспомогательные устройства

2 . auxiliary devices 2.однобалочная рукоять ковша

3. hinged-joint boom 3. Талый грунт

4. single-girder bucket arm 4.канатный механизм напора

5. high-grade material 5.глубина промерзания

6 . rectangular cross-section 6.шарнирно- сочлененная стрела

7.Removal of soil blocks 7.прямоугольное сечение

8.Outreach of discharge conveyor 8.высокопрочные материалы

9.Unfrozen soil 9.вылет транспортера

10.Freezing depth 10.выемка целиков грунта

11.габаритные размеры

ЗАДАНИЕ 2-3

Просмотрите текст и перечислите машины, описанные в нем. Переведите текст-время 15 мин (каждый студент переводит один раздел).

LOADERS AND OTHER EXCAVATORS

1.In addition to the members of the crane-shovel family, there are a number of other pieces of equipment suitable for excavating and loading haul units. One of the items of equipment most frequently used for such purposes is called a wheel loader. The wheel loader is a wheeled version of e machine also called e scoop loader, front-end loader, bucket loader, or tractor-shovel. Track-type loaders are also available.

Many of these machines, particularly the track-type loader, closely resemble the tractor, The factors effecting speed and usable power (traction, rolling and grade resistance, etc) are the same for loaders as they are for tractors.

Loader buckets are available in a wide range of sites. Two types of buckets are usually available: a solid or scoop bucket and a multi-segment bucket. The multi-segment bucket has more flexibility than the solid bucket since it can be used like a clamshell, dozer, or scraper as well as a scoop shovel.

2. Besides the members of the crane-shovel family and front end loaders, there are several other types of equipment used for excavating and loading. These include elevating loaders, bucket wheel excavators, and trenching machines. All of these machines combine some type of cutter with a conveyor belt for moving excavated material to hauling units. Dual belts are frequently used with these machines so that haul units may be loaded on alternate sides of the machine, thus eliminating the time lost in spotting haul unites.

3.Elevating loaders combine a scoop-type cutting head with a belt loader. Usually, the machine is towed by one or more earthmoving tractors, although the loader may be equipped with its own propelling units. Such machines are capable of excavating and loading several thousand bank cubic yards of material per hour under favorable conditions.

Bucket wheel or continous -wheel excavators combine large bucket wheel-type cutters with a belt loading system. These machines are usually self-propelled and designed for high production rates. They, like the elevating loader, are best suited to large. relatively flat excavation areas. These machines may yield low excavating and loading unit costs on large earthmoving project such as dam construction, mining, etc.

4. Trenching machines were developed to dig trenches for cables and pipelines faster and more economically then excavators like the hoe or the dragline. Major types of trenching machine include the continuous chain trencher, the ladder-type trencher, and the wheel-type trencher.

Continuous-chain trenchers use a series of digging scoops spaced along a continuous, power-driven chain to provide digging action. They are used for relatively shallow, narrow trenches and are available in very small sizes for laying power and communications lines. They are usually limited in digging depth to 6 ft or so.

Ladder-type trenchers operate somewhat like continuous-chain trenchers but are larger and heavier. They are available in a wide range of bucket widths and can excavate to a depth of 30 ft or more. Thus, they have the greatest depth capability of any trencher.

Wheel -type trenchers use a bucket wheel-type of excavator for digging action. They are also available in a range of bucket widths but are limited in digging depths to around 10 ft.

ЗАДАНИЕ 2-4

Прочтите текст, осветите следующие положения:

1)классификация экскаваторов по их массе,

2)область применения,

3)факторы, определяющие выбор той или иной машины.

HYDRAULIC EXCAVATORS: INCREASES IN EFFICIENCY

By Margaret Briggs

Just as the gradual introduction some 15 to 20 years ago of the hydraulic excavator marked a major step forward in performance and precise control compared with rope operated machines, so more recent developments in the hydraulic systems have achieved a substantial increase in efficiency.









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