Exercise 2. Read Text A and define the functions of the underlined verbs “to be” and “to have”.
Exercise 3. Translate the following sentences and define the functions of ed-forms:
1. Powered machines have increased the speed of work to a great extent.
2. Quick-attach systems simplified attachments mounting.
3. A bucket is fixed at the arm end.
4. The machine could not swing when used in tight turn areas.
5. Modern excavators are fitted with electric motors.
6. The counterweight provided additional lifting capacity.
7. Machines are more environmentally friendly if fitted with fuel cells.
8. Hydraulic devices have expanded excavator applications.
9. A loader is a machine employed in construction.
Exercise 4. Translate Text B without a dictionary:
Text B
EXCAVATOR APPLICATION
Excavators are used extensively in numerous fields, including the following:
· wood removal in forests
· normal grading work and landscaping
· demolition of structures, and removal of debris
· mining industry
· dredging of rivers
· installation of piles in foundations
· digging of foundations, holes and trenches
· handling of heavy materials
· laying of heavy pipes
Many excavators feature quick-attach mounting systems for simplified attachment mounting, dramatically increasing the machine’s utilization on the jobsite. Excavators are usually employed together with loaders and bulldozers. Most wheeled versions, and smaller, compact excavators have a small backfill (or dozer-) blade. This is a horizontal bulldozer-like blade attached to the undercarriage and is used for pushing removed material back into a hole. Prior to the 1990s, all excavators had a hang over, or conventional counterweight that hang off the rear of the machine to provide more digging force and lifting capacity. This became a hindrance in tight turn areas – the machine could not swing the second half of its cycle due to restricted turn radius. In the early 1990s The Komatsu Engineering Company launched a new concept excavator line that did away with the conventional counterweight design, and so started building the world’s fist tight tail swing excavators (PC128, PC138, PC228, PC308). These machines are now widely used throughout the world.
Notes:
debris - обломки, строительный мусор
dredge - углублять
hang - вешать
Unit 5
Grammar: Ing-forms.
Text A
COMPACT EXCAVATOR
Excavators come in a wide variety of sizes. The smaller ones are called mini-excavators or compact excavators.
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A compact hydraulic excavator or mini excavator is a tracked or wheeled vehicle with an approximate operating weight from 0.7 to 7.5 tonnes. It generally includes a standard backfill blade and features independent boom swing. The compact hydraulic excavator is also referred to as a mini excavator.
The compact hydraulic excavator is somewhat different from other construction equipment in that all movements and functions of the machine are accomplished through the transfer of hydraulic fluid. The compact excavator's workgroup and blade are activated by hydraulic fluid acting upon hydraulic cylinders. The excavator's slew (rotation) and travel functions are also activated by hydraulic fluid powering hydraulic motors.
Most compact hydraulic excavators have three distinct assemblies: house, undercarriage and workgroup.
The house structure contains the operator's compartment, engine compartment, hydraulic pump and distribution components. The house structure is attached to the top of the undercarriage via a swing bearing. The house, along with the workgroup, is able to rotate or slew upon the undercarriage without limit due to a hydraulic distribution valve supplying oil to the undercarriage components.
Slewing refers to rotating the excavator's house assembly. Unlike a conventional backhoe, the operator can slew the entire house and workgroup upon the undercarriage for spoil placement.
The undercarriage consists of rubber or steel tracks, drive sprockets, rollers, idlers and associated components/structures. The undercarriage supports the house structure and the workgroup.
The workgroup of a compact hydraulic excavator consists of the boom, dipper or arm, and attachment (e.g. auger, bucket or breaker). It is connected to the front of the excavator's house structure via a swing frame allowing the workgroup to be hydraulically pivoted left or right to achieve offset digging for trenching parallel with the tracks.
The primary purpose of boom swing is for offset digging around obstacles or along foundations, walls or forms. A secondary use is cycling in areas too narrow for cab rotation. Independent boom swing is one of the major advantages of a compact excavator over other excavation equipment.
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The backfill blade is used for grading, levelling,backfilling, trenching, and general dozer work. The blade can be used to increase dump height and digging depth depending on its position in relation to the excavator's workgroup, this makes it very versatile.
There are two distinct classes of compact excavators, conventional tail swing units that have a rear counterweight that will extend beyond the tracks when the house rotates, and zero-tail swing units with a house whose diameter stays within the width of the tracks through full rotation. Zero-tail swing units allow the operator to focus on digging and not watching where he or she is swinging.
Active Vocabulary:
approximate - приблизительный; приближаться
backfill - засыпка (траншей)
accomplish - совершать, выполнять
transfer - переносить, передавать
house - корпус
contain - содержать
compartment - отделение
valve - клапан
entire - полный, целый
spoil - земля, вынутая при земляных работах
sprocket -цепное, зубчатое колесо; звездочка
idler - направляющий шкив, ролик
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dipper - ковш
achieve - достигать, добиваться
offset - ответвление, отвод
obstacle - препятствие, помеха
conventional - обычный, традиционный
Exercise 1. Answer the following questions:
1. What does a compact excavator include and feature?
2. How does hydraulic excavator differ from some other construction equipment?
3. How is the house structure attached to the top of the undercarriage?
4. What is one of the major advantages of a compact excavator?
5. What is the backfill blade used for?
6. How many and what classes of compact excavators are there?
Exercise 2. Read Text A and define the part of speech and the function of the underlined words.
Exercise 3. Translate the following sentences paying attention to ing-forms:
1. Lifting and moving of heavy loads is accomplished by using a forklift truck.
2. Safety rails and revolving turntables are normally fitted for the prevention of tilting.
3. A counterweight is utilized for balancing the load being lifted.
4. The mast does the work of raising and lowering a load.
5. The interlocking rails may either have rollers or bushings as guides.
6. The function of a battery powered platform truck introduced in 1906 was moving the luggage.
7. During World War I different types of material handling equipment were being developed.
8. In 1917 Clark in the USA began developing and using powered tractors.
9. Allowing the operator to move forks the sideshifter provides easier positioning of a load.
10. A loader can move stockpiled building materials from the ground level.
Exercise 4. Translate Text B without a dictionary:
Text B
DRAGLINE HISTORY
The dragline was invented in 1904 by John W. Page of Page Schnable Contracting for digging the Chicago Canal. In 1912 it became the Page Engineering Company, and a walking mechanism was developed a few years later, providing draglines with mobility. Page also invented the arched dragline bucket; a design still commonly used today by draglines from many other manufacturers, and in the 1960s pioneered an archless bucket design.
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In 1910 Bucyrus International entered the dragline market with the purchase of manufacturing rights for the Heyworth-Newman dragline excavator. Their "Class 14" dragline was introduced in 1911 as the first crawler mounted dragline. In 1912 Bucyrus began to use electricity as a power source for large stripping shovels and draglines used in mining.
In 1914 Harnischfeger Corporation, (established as P&H Mining in 1884 by Alonzo Pawling and Henry Harnischfeger), introduced the world's first gasoline engine-powered dragline. An Italian company, Fiorentini, from 1919 produced dragline excavators licensed by Bucyrus.
In 1939 the Marion Steam Shovel Dredge Company (established in 1880) built its first walking dragline. The company changed its name to the Marion Power Shovel Company in 1946 and was acquired by Bucyrus in 1997. In 1988 Page was acquired by the Harnischfeger Corp., makers of the P&H line of shovels, draglines, and cranes.
Draglines, unlike most equipment used in earth-moving, have remained relatively unchanged in design and control systems for almost 100 years. Over the last few years, some advances in dragline systems and methodologies have occurred.
UDD stands for Universal-Dig-Dump. It represents the first fundamental change to draglines for almost a century. Instead of using two ropes (the hoist rope and the drag rope) to manipulate the bucket, a UDD machine uses three ropes, two hoists and one drag. This allows the dragline operator to have much greater selectivity in when to pick up the bucket, and in how the bucket may be dumped. UDD machines generally have higher productivity than a standard dragline. The improvements justify their costs.
Notes:
arch - арка, дуга; изгибать дугой
purchase - покупка
strip - полоса; снимать слой
acquire - приобретать
Unit 6
Grammar: Infinitive;
Infinitive Constructions.
Text A
DRAGLINE EXCAVATOR
Dragline excavation systems are heavy equipment used in civil engineering and surface mining. In civil engineering the smaller types are used for road and port construction. The larger types are used in strip-mining operations to move overburden (soil layers) above coal. Draglines are amongst the largest mobile equipment, and weigh in the vicinity of 2000 metric tonnes, though specimens weighing up to 13,000 metric tonnes have also been constructed.
A dragline bucket system consists of a large bucket which is suspended from a boom (a large truss-like structure) with wire ropes. The bucket is manoeuvred by means of a number of ropes and chains. The hoist rope, powered by large diesel or electric motors, supports the bucket and hoist coupler assembly from the boom. The drag rope is used to draw the bucket assembly horizontally. By skillful manoeuvre of the hoist and the drag ropes the bucket is controlled for various operations.
In a typical cycle of excavation, the bucket is positioned above the material to be excavated. The bucket is then lowered and the drag rope is then drawn so that the bucket is dragged along the surface of the material. The bucket is then lifted by using the hoist rope. A swing operation is then performed to move the bucket to the place where the material is to bedumped. The drag rope is then released causing the bucket to tilt and empty. This is called a dump operation.
The bucket can also be 'thrown' by winding up to the jib and then releasing a clutch on the drag cable. This would then swing the bucket like a pendulum. Once the bucket had passed the vertical, the hoist cable would be released thus throwing the bucket. On smaller draglines, a skilled operator could make the bucket land about one-half the length of the jib further away than if it had just been dropped. On larger draglines, only a few extra metres may be reached.
Draglines have different cutting sequences. The first is the side cast method using offset benches*; this involves throwing the overburden sideways onto blasted material to make a bench. The second is a key pass. This pass cuts at the toe of the new high wall and also shifts the bench further towards the low wall. This may also require a chop pass if the wall is blocky. A chop pass involves the bucket being dropped down onto an angled highwall to scale the surface. The next sequence is the slowest operation. However, this pass moves most of the material. It involves theaccess to bottom of the material to lift it up to an elevated bench level. The final cut if required is a pull back, pulling material back further to the low-wall side.
The primary limitations of draglines are their boom height and boom length, which limit where the dragline can dump the waste material. Another primary limitation is their dig depth, which is limited by the length of rope the dragline can utilize. A dragline is most efficient excavating material below the level of its base. While a dragline can dig above itself, it does so inefficiently and is not suitable to load piled up material (as a rope shovel can).
Despite their limitations, and their extremely high capital cost, draglines remain popular with many mines, due to their reliability, and extremely low waste removal cost.
*bench - терраса, уступ
Active Vocabulary:
surface - поверхность
mining - горное дело, разработка недр
strip - полоса, снимать (слой)
specimen - образец, экземпляр
draw - тащить, тянуть
release - освобождать, отпускать
throw - бросать
skilled - квалифицированный
drop - падать, ронять
sequence - последовательность, следование
involve - включать, вовлекать
waste - отходы, пустая порода
Exercise 1. Answer the following questions:
1. What types of draglines are used for road construction?
2. What does a dragline bucket system consist of?
3. What means is the bucket manoeuvred by?
4. How is the typical cycle of excavation performed?
5. How many cutting sequences do draglines have?
6. What are the primary limitations of draglines?
7. Why do draglines remain popular?
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