Английский язык в сфере профессиональной коммуникации. Горные машины. Учебное пособие

SOME TYPES OF MACHINES USED

IN STRIPPING OPERATIONS

Deposits of nonmetallic minerals are usually covered by valueless materials which must be removed in order to allow excavation by the open-pit process. There is now available a large variety of motorized stripping and excavating equipment which is selected on the basis of the depth of the overburden and the amount of overburden to be moved each year.

For shallow overburden averaging only a few feet in depth and where only a small acreage needs to be cleaned each year, the modern crawler tractor with bulldozer or bullgrader equipment is probably the most economical method of operation, provided the overburden does not need to be carried any great distance or the rock surface is not too uneven. One man, the tractor operator, can carry on the entire operation. This plan offers an additional advantage in that the same equipment can also be used to advantage in the pit for grading roads, cleaning the floor, and bunching materials in front of the loading shovel. A ripper may also be used behind the tractor fitted with the bulldozer.

Where a greater amount of material is to be moved or where longer hauls are necessary than are practical for the “dozer” type of equipment, consideration should be given to the 2-wheeled scraper or the 4-wheeled scraper hauled behind a tracklaying tractor. The 2-wheeled scraper can be moved and turned easily, and, as it dumps backward, the spoil can be dumped exactly where desired, as over banks and down in the gullies. The 4-wheeled scraper can spread their loads while dumping.

Scrapers are available in capacities from 3 cu. yd. struck capacity up to 42.1 cu. yd. and can be operated very economically. To obtain maximum results with sizes above 15 cu. yd. a pusher tractor should be used to aid in loading. A single tractorscraper unit can take care of the stripping work for most quarry or sand-and-gravel operations, and when not in use for stripping, the tractor can be used to good advantage for other work in the pit or around the plan. This unit also requires only a one-man crew, as the tractor driver handles the operations of loading and dumping from controls just behind his seat on the tractor.

Sometimes the tractor which pulls the scraper is equipped with a bulldozer, thus eliminating the need for a second tractor. The bulldozer can be used for leveling the hauling roads or for spreading the spoil.

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The tractor-scraper combination, being a self-loading hauling unit, has the advantage of being able to move the spoil or waste material, as it is excavated, back from the pit edge, thus eliminating dangerous slides. Its ability to haul its own load often makes possible a more advantageous disposal of the spoil than is economically possible with the ordinary side-casting method of overburden removal. Many operators opening new pits with tractor-scraper units arrange the haul so that spoil can be wasted into old abandoned pits. This method eliminates later rehandling of the overburden.

Where the overburden is comparatively shallow, that is, from 5 to 15 ft. deep, tractor-scraper units usually handle all the stripping, thus enabling the shovels and draglines to put all their time on the productive job of material handling.

After the overburden has been removed from the pit, the tractor-scraper combination can be converted from an earth-moving tool into a material-handling unit. When used for material handling from the pit, tractor-scraper units normally dump over a ramp on a conveyer leading directly into the plant, or, where the plant is some distance from the pit, into trucks. The usual big-capacity scraper hauls enough material in one load to fill from one to four trucks. Once the material had gone through the plant, tractor-scrapers frequently can be used for stock-piling, and for reclaiming and loading from stockpiles.

Rippers have increased the range of practical usefulness for scrapers by providing good fragmentation for handling hardpan, shale, clay and limestone overburden. These tools have from one to five teeth and penetrate to a depth of 20 to 30 inches. On many jobs scraper efficiency is increased from 25 to 50 per cent because of the shorter loading time and larger loads. Tractor usefulness is increased by using a bulldozer on the front and a ripper on the rear with the same tractor and there is no loss of time for equipment change-overs.

The latest innovation in stripping is the use of high-speed, rubber-tired twoand four-wheeled tractors for long-haul work. These are equipped with either trailers or scraper hauling units. Both types are available in sizes from 8 to 33 cu. yd. struck measure. This type of tractor-trailer equipment, because of its large capacity and truck-speed, can do the work of trucks and trains. In certain conditions a tractorscraper outfit can perform the task of the shovel or dragline because of its selfloading feature, when used with a pusher. One of the advantages of the tractorscraper combination is its ability to handle so many incidental jobs, such as building ramps into pits, building truck roads from pit to plant, digging drainage ditches, grading for railroads, constructing dams, etc.

The double application of tractors and dump trailers to stripping and the hauling of rock and other quarry and pit products has enhanced their value to the operator. Both track-type trailers and pneumatic rubber-tired trailers are used extensively and give substantial savings in maintenance cost.

As stripping must precede excavating it is usually done when difficult weather and road conditions are encountered. Heavy frost necessitates the use of sturdy shovels to insure continuous digging and hauling equipment that is able to perform continuously under these adverse conditions. A modern heavy-duty ripper can be employed to break up frost effectively. Using a tool such as this relieves the shovel of

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this duty so that it can concentrate on production alone. Ripper application would not tie up an expensive piece of equipment like a shovel and would assure uninterrupted production.

There has been an increase in the use of rubber-tired equipment for overburden removal. Bottom-dumping trailers mounted on pneumatic tires and drawn by shortwheelbase truck-type tractors provide large capacity and tractive power combined with speed and maneuverability. They are available in pay-load capacities ranging from 9 to 22.7 cu. yd., with power ratings from 100 to 200 h. p., weight from 28,000 to 56,000 lbs., and speed from 2 to 24 or 27 m. p. h. the trailer bodies have wedgeshaped hoppers with smooth, unobstructed sides and bottom doors operated by compressed air.

Rear-dumping bodies, mounted on the truck chassis, employ the same features. They range in capacity from 8.2 to 13.0 cu. yd., have the same horse-power range as the bottom-dumping machines, weight from 20,000 to 30,000 lbs., and range in speed from 1.9 to 24.9 m. p. h. the dumping is done hydraulically.

In some conditions stripping can be handled best with a power shovel. Stripping shovels are available in any capacity from 3/8 cu. yd. modern machines are crawler-mounted and may be operated by gasoline or Diesel engines or electric motors. Most crawler-mounted shovels of ⅜ cu. yd. or grater capacity have the “high lift” feature by which they can be equipped with longer booms and sticks to increase the dumping radius and additional counterweight to compensate for the longer reach. These machines are usually used for the average small quarry or sand- and-gravel pit stripping job. They are extremely fast, turning out four or five digging cycles per minute and are highly mobile and able to traverse almost any surface on which they are required to operate.

Large electric-powered shovels up to 35 cu. yd. capacity or large electric draglines carrying booms up to 250 ft. in length are available for stripping but the cost of this equipment limits their application.

In the course of development of the stripping work, the shovels have greatly increased in dipper capacity from 2 ½ cu. yd. to 33 cu. yd., in the radius of digging and in the dumping radius. The large modern machine has an advantage in its increased bail pull, enabling it to dig a higher bank without leaving material hanging at the top, and it can dig at a slightly greater distance from the shovel, thus preventing the bank from interfering with the shovel. The modern large shovel is available with special front-end combinations, using long booms and handling correspondingly smaller dippers for deep overburden digging.

In stripping sand-and-gravel pits the draglines are usually used. This makes an excellent arrangement as no additional stripping equipment is required. It may also be practical to economize on the equipment investment by using a small dragline for stripping and the same machine with a clam-shell for working stockpiles. In comparison with the shovel, the dragline works over a greater radius, has the ability to stay on the side of the bank, digs at a considerably lower level and still load into a hopper, truck, trailer, or car. Many of these draglines are of ⅜, ½, and ¾ cu. yd. capacity, and are fully convertible.

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Where the overburden is material which need not be blasted and the width of the operation is limited, it is possible to install a slack-line cableway excavator with the head tower and tail tower arranged so that they can be transported lengthwise of the cut. In some cases the head tower can be stationary, but this limits the area that can be stripped. There are two general methods. One is the method of digging near the tail tower and dumping in front of the head tower. In the other the head tower on the original ground surface and the tail tower in an abandoned portion of the quarry are used, the digging being done in front of the head tower and the spoil being deposited in front of the tail tower.

There are also places where a power drag-scraper may be used; namely, where the material is loose enough to be plowed without difficulty, where the depth of the overburden does not exceed 10 ft., where the maximum haul does not exceed 300 ft., and where the surface of the material to be uncovered is fairly even.

Under certain conditions it is possible to use a belt conveyer loaded by a small dragline or shovel to convey the material to the spoil bank.

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UNIT XI. RUBBER-TIRED LOADERS

I. Прочитайте следующие слова, группы слов и предложения. Предложения переведите.

1.to add. The major trend is to add power and capacity for most new loaders.

2.to enable. The loader has a 22 cubic-yard bucket, which enables it to load a 170-ton haul truck.

3.to exist. The company also added a 3 cubic-meter wheel loader to its line.

4.to encounter. New problems were encountered while testing a new loader.

5.intermediate. Few manufacturers added a small to intermediate sized loader to its equipment line.

6.internal. Acceptable sound levels are easily met with the unique internal and external sound insulation designs.

7.to market. Many new machines were marketed by this company.

8.production rate – производительность. This shovel is designed for high production rate.

9.range – (from – to). Buckets range from 4,5 to 22 cubic yard capacity.

10.rubber-tired loader – погрузчик на резиновом ходу. Rubber-tired loaders were manufactured in Russia many years ago.

II. Выполните упражнения, способствующие извлечению информации из текста:

RUBBER-TIRED LOADERS

Several equipment companies including Volvo BM, John Deere and Company, and International Harvester Company have added new rubber-tired loaders to their equipment lines. The major trend appears to be added power and capacity for most new loaders being marketed during 1979.

John Deere marketed its new 260-horsepower loader, the JD844 for the first time in June 1979. The JB844 is the largest, most powerful four-wheel-drive articulated loader that the company produces. Buckets ranging from 4,5 to 7-cubic- yard capacity handle loads in excess of 15,000 bounds per cycle. The John Deere V-8 turbocharged Diesel engine produces 260 net horsepower which is converted to a maximum forward speed of 23,4 miles per hour by a single stage torque converter transmission.

The world's largest single engine rubber-tired front-end loader was marketed by International Harvester, late in 1979. The IH 580 has a standard 22-cubic-yard bucket which enables it to load a 170-ton haul truck in six cycles with a total loading time of 4,5 minutes. A Detroit 12V-149TI turbocharged engine develops the machine's 1,075 flywheel horse-power. Three of the IH 580 loaders have been field tested in coal and uranium mines with few problems encountered.

Volvo BM of Sweden added a new 1,95-cubic-meter (2,5 cubic-yard) wheel loader to its product list during 1979, being, one of the few manufacturers to add a small to intermediate sized loader to its equipment line. The new 4400 machine is designed for both excellent production rate and environmental considerations.

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Acceptable sound levels are easily met with the unique internal and external sound insulation designs.

Volvo also added a 2,3-cubic-metre (3,12-cubic-yard) wheel loader to its existing line, the 4500 model, which replaced the older 1240 model. The new 4500 has a 25 percent higher breakout force than the older 1240 machine and also has a turning radius of 5,52 meters (18 feet), making it faster and more maneuverable.

COMMENTARY

1.four-wheel-drive articulated loader – полноприводной погрузчик

2.the John Deere V-8 turbocharged Diesel engine – дизельный двигатель

V-8 с турбонадувом

3.a single stage torque converter transmission – трансмиссия с одноступенчатым гидропреобразователем

4.the machine's 1,075 flywheel horse-power – маховик мощностью

1.075 л.с.

III. Прочитайте первый абзац и найдите ответы на следующие вопросы. Ответы прочитайте.

1.О каких компаниях идет речь в тексте?

2.Что прибавилось в их оборудовании?

3.В каком направлении разработан погрузчик?

4.Почему модель JD844 является самой большой и мощной?

5.Какова емкость ковша?

IV. Переведите второй абзац текста расскажите по-русски о рабочей характеристике погрузчика компании “IH”.

V. Переведите текст до конца.

VI. Расскажите по-русски об особенностях погрузчика компании

“Volvo BM”.

VII. Определите, какие предложения соответствуют содержанию текста.

1.Three companies have added a new excavator to their equipment line.

2.The major trend is to increase the size of new loaders.

3.John Deere marked its new 260 horsepower loader.

4.Three of the IH580 loaders have been field tested in coal and uranium mines.

5.The world’s largest single engine rubber-tired front-end loader was marked

by I.H.

6.Volvo BM of Germany added a new 3-cubic-metre wheel loader to its product list.

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VIII. Прочитайте текст и постарайтесь понять его содержание при помощи данных слов:

articulated – шарнирный; assembly – агрегат;

augment – увеличивать, добавлять; bale – кипа, тюк;

casualty – жертва, пострадавший; chip – стружка, щепка;

debris – осколки; обломки пород; expiration – истечение (срока); highway – шоссе;

landscape chores – ландшафтные работы

LOADERS

A loader is an engineering vehicle (often used in construction) that is primarily used to “load” material (asphalt, demolition debris, dirt, feed, gravel, logs, raw minerals, recycled material, rock, sand, wood chips, etc.) into or onto another type of machinery (dump truck, conveyor belt, feed-hopper, rail-car, etc.).

A loader (also known as: bucket loader, front loader, front-end loader, payloader, scoop loader, shovel, skip loader, and/or wheel loader) is a type of tractor, usually wheeled, sometimes on tracks, that has a front mounted square wide bucket connected to the end of two booms (arms) to scoop up loose material from the ground, such as dirt, sand or gravel, and move it from one place to another without pushing the material across the ground. A loader is commonly used to move a stockpiled material from ground level and deposit it into an awaiting dump truck or into an open trench excavation.

The loader assembly may be a removable attachment or permanently mounted. Often the bucket can be replaced with other devices or tools, for example, many can mount forks to lift heavy pallets or shipping containers, and a hydraulically-opening

“clamshell” bucket allows a loader to act as a light dozer or scraper. The bucket can also be augmented with devices like a bale grappler for handling large bales of hay or straw.

Large loaders, such as the Kawasaki 95ZV-2, John Deere 844J, Caterpillar 950H, Volvo L120E, Case 921E, or Hitachi ZW310 usually have only a front bucket and are called front loaders, whereas small loader tractors are often also equipped with a small backhoe and are called backhoe loaders or loader backhoes or JCBs, after the company that first invented them.

The largest loader in the world is LeTourneau L-2350. Currently these large loaders are in production in the Longview, Texas facility. The L-2350 uses a diesel electric propulsion system similar to that used in a locomotive. Each rubber-tired wheel is driven by its own independent electric motor.

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Loaders are used mainly for uploading materials into trucks, laying pipe, clearing rubble, and digging. A loader is not the most efficient machine for digging as it cannot dig very deep below the level of its wheels, like a backhoe can. Their deep bucket can usually store about 3-6 cubic meters (exact number varies with the model) of earth. The front loader’s bucket capacity is much bigger than a bucket capacity of a backhoe loader. Loaders are not classified as earthmoving machinery, as their primary purpose is other than earthmoving.

Unlike most bulldozers, most loaders are wheeled and not tracked, although track loaders are common. They are successful where sharp edged materials in construction debris would damage rubber wheels, or where the ground is soft and muddy. Wheels provide better mobility and speed and do not damage paved roads as much as tracks, but provide less traction. In construction areas loaders are also used to transport building materials – such as bricks, pipe, metal bars, and digging tools – over short distances.

Loaders are also used for snow removal, using their bucket or a snowbasket, but usually using a snowplow attachment. They clear snow from streets, highways and parking lots. They sometimes load snow into dump trucks for transport.

High-tip buckets are suitable for light materials such as chip, peat and light gravel and when the bucket is emptied from a height.

Unlike backhoes or standard tractors fitted with a front bucket, many large loaders do not use automotive steering mechanisms. Instead, they steer by a hydraulically actuated pivot point set exactly between the front and rear axles. This is referred to as “articulated steering” and allows the front axle to be solid, allowing it to carry greater weight. Articulated steering provides better maneuverability for a given wheelbase. Since the front wheels and attachment rotate on the same axis, the operator is able to “steer” his load in an arc after positioning the machine, which can be useful. The trade-off is that when the machine is “twisted” to one side and a heavy load is lifted high, it has a greater risk of turning over to the “wide” side.

Front loaders gained popularity during the last two decades, especially in urban engineering projects and small earthmoving works. Many engineering vehicle manufacturers offer a wide range of loaders, the most notable are those of John Deere, Caterpillar, Case, Volvo, Komatsu, Liebherr, JCB and Kawasaki, being the longest, on-going manufacturer of articulated wheel loaders in the world.

Popular additions to compact utility tractors and farm tractors are front-end loaders, also referred to as a FEL. Compact utility tractors, also called CUTs are small tractors, typically with 18 to 50 horsepower (37 kW) and used primarily for grounds maintenance and landscape chores. There are 2 primary designs of compact tractor FELs, the traditional dogleg designed style and the curved arm style.

John Deere Tractor manufactures a semi-curved loader design that does not feature the one piece curved arm, but also is not of the traditional two piece design. New Holland Ag introduced a compact loader with a one piece curved arm on its compact utility tractors, similar one piece curved arm loaders are now available on compact tractors on many brands including Case/Farmall, and some Montana and Kioti tractors. Kubota markets traditional loader designs on most of its compact

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tractors but now features a semi-curved loader design similar to the John Deere loader design on several of its small tractors.

While the front-end loaders or CUT size tractors are capable of many tasks, given their relatively small size and low capacities when compared to commercial loaders, the compact loaders can be made more useful with some simple options. A toothbar is commonly added to the front edge of a loader bucket to aid with digging. Some loaders are equipped with a quick attach (QA) system, the QA system allows the bucket to be removed easily and other tools to be added in its place. Common additions would include a set of pallet forks for lifting pallets of goods or a bale spear for lifting hay bales.

A skid loader is a small loader utilizing four wheels with hydraulic drive that directs power to either, or both, sides of the vehicle. Very similar in appearance and design is the track loader, which utilizes a continuous track on either side of the vehicle instead of the wheels. Since the expiration of Bobcat’s patent on its quickconnect system, newer tractor models are standardizing on that popular format for front-end attachments.

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UNIT XII. HYDRAULIC EXCAVATORS

I. Прочитайте следующие слова, группы слов и предложения. Предложения переведите.

1.to apply – применять. modern computer technology has now been applied in designing these excavators.

2.as well as – (а) также (и), так же как. Modular construction is employed for large hydraulic excavators as well as dragline.

3.to appear – появляться, казаться. Japanese, Russian and American models of hydraulic excavators appeared in the late 1970s.

4.to believe – верить, полагать. The computer fitted on this excavator is believed to control an energy saving system.

5.to create – создавать, творить. This company is going to create a highly innovative excavator.

6.despite – несмотря на. Despite the size of the Marion 3500 its modular form makes it possible to assemble in only five days.

7.to exhibit – показывать, выставлять. This machine also exhibits feature found on other models of hydraulic mining excavator.

8.feature – особенность, характерная черта. Hydraulic excavators for mining operations have many important positive features.

9.to improve – улучшать(ся). The cab can be moved hydraulically in order to improve vision.

10.to intend – предполагать, предназначать. This dragline is intended for stripping operations.

11.to introduce – вводить, представлять. Komatsu intends to introduce larger machines.

12.to monitor – проверять, контролировать. An electrical sensing system monitors twenty three functions.

13.a number of – ряд, несколько. Manufacturers designed some excavators with a number of significant features.

14.recently – недавно.New models of backshoes have recently appeared.

15.to sponsor – предлагать, финансировать. A 600t hydraulic excavator jointly sponsored in Japan is under active consideration.

II. Прочитайте текст “Hydraulic excavators” и постарайтесь понять его содержание.

III. Найдите в тексте ответы на следующие вопросы.

1.What models of Hydraulic excavators are achieved during the last years?

2.What engines are used on hydraulic excavators?

3.What are advantages of large modular hydraulic excavators?

4.How is the operator’s cab equipped?

5.What new technology is applied in designing large excavators?

6.What excavators will be produced in future?

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