KEYS & PINS

The main function of a key is to transmit torque between a shaft and a machine part assembled on it. In most cases keys prevent relative motion, both rotary and axial. In some constructions keys allow an axial motion between the shaft and the hub, such keys are called feather or spine keys. In spite of the tendency to standardize there are many key types in use by various manufacturers.

According to various characteristics keys can be distinguished as straight and tape-red; rectangular, dovetailed, chamfered round and disk-shaped; radial and tangential, and (according to their use) for light duty and for heavy duty.

Geometrically pins can be divided into cylindrical pins, called straight pins, and conical or taper pins. Dynamically pins can be classified as those used only to locate the relative position of two parts when there is little or no force acting upon the pin, and those that fasten two or more parts together and are subjected to considerable stresses, which are, mostly in shear but sometimes in bending. Locating pins are called dowel pins or simply dowels. A connecting pin, like a dowel, may be used either as a permanent connection or as a fulcrum for a movable joint.

Notes and commentary:

1. in most cases - у більшості випадків

2. feather or spline key - шпонка напрямна або призматична

3. in spite of- не зважаючи на

4. according to- згідно

5. dovetailed key - шпонка у вигляді ластівкового хвосту

6. chamfered round key- циліндрична шпонка або шпонка зі скошеними ребрами

7. disk-shaped key- дископодібна шпонка

8. radial and tangential key- радіальна або тангенціальна шпонка

9. for light and for heavy duty- для малих і великих навантажень

10. are subjected to- піддаються

11. which are mostly in shear but sometimes in bending- які зазвичай зрізуються, але іноді вигинаються

12. either…or - або…або

Task1. Answer the following questions:

1. What is the main function of a key?

2. What keys are called feather or spline keys?

3. How can keys be distinguished according to various characteristics?

4. How are keys classified according to their use?

5. How can pins be divided geometrically?

6. How can pins be classified dynamically?

7. What are locating pins?

8. What are connecting pins?

Task 2. Find in the text English equivalents for the following words and word combinations:

шпонка напрямна, малі навантаження, обертальний рух, шпонка зі скошеними ребрами, крутний момент, шпонка у вигляді ластівкового хвоста, виробники, не звертаючи увагу на, вісь.

Task 3. Use the following words and phrases in sentences of your own:

straight pins, taper pins, to be subjected to considerable stresses, permanent connection, a fulcrum for a movable joint.

PRESS, SHRINK AND FRICTION JOINTS

A press joint, also called a force joint, is obtained by forcing a shaft into a hole that is slightly smaller then the shaft. This is possible because of the elasticity of the materials which produces the grip that holds the hub and shaft together.

A shrink joint differs from a press joint chiefly by the method of assembling it. The hub is heated to expand its bore and to slip it on the shaft. When the hub cools down to the temperature of the shaft, the grip is produced in the same way as in the force joint. The shrink joint is also used to connect machine parts by means of special rings, anchors, and tie rods.

In a friction joint the holding grip is produced by the conical shape of the shaft end and the hub bore and by the pull of a nut, or by a slotted hub whose bore is smaller than the shaft and which is spread by s wedge when the joint is being assembled.

The assembling of a shaft and a hub by means of a press joint is simpler than that with a shrink joint especially if a hydraulic press of a sufficient capacity is available. Shrink joints are used mainly in places where it is difficult or impossible to assemble a press joint, as in the case of rings or anchors. On the other hand, shrink joints assemblies with the same interference as press joints give more than three times the holding power against both torsion and axial pull. This superior effectiveness is due to the absence of abrasion between the surfaces of the shaft and the hub during assembly.

All three joints are used when machine parts must be connected more securely than can be accomplished with a key or screw joint, especially when they are subjected to shock or vibration.

Notes and commentary:

1. a press joint – пресова посадка

2. is obtained by forcing a shaft into hole – отримується при впресуванні валу в отвір

3. which produces the grip that holds the hub and shaft together – той, що затискає і утримує втулку і вал разом

4. a shrink joint – гаряча посадка

5. the hub is heated to expand its bore and to slip it on the shaft – втулка нагрівається для розширення її внутрішнього діаметру і посадки на вал

6. by means of - за допомогою

7. tie rod – з'єднувальна тяга

8. the conical shape of the shaft end and the hub bore – конічна форма кінця валу та отвору втулки

9. the pull of a nut – затягування гайки

10. as in the case – як і у випадку

11. on the other hand – з іншого боку

12. more than three times – більш, ніж в три рази

13. when they are subjected to – коли вони піддаються

Task 1. Answer the following questions:

1. How is a press joint obtained?

2. What is the difference between a shrink joint and press joint?

3. What is the shrink joint used for?

4. How is the holding grip produced in a friction joint?

5. When are all three joints used?

Task 2. Retell the text using the following words and word combinations:

a press joint, to force a shaft into a hole, elasticity, to produce the grip, shrink joint, the method of assembling, the hub anchors, the conical shape of the shaft, a hydraulic press, absence of abrasion.

Task 3. Translate into Ukrainian paying attention to the word " by" .

1. This high pressure created by the compressed gases causes the shaft to turn or rotate.

2. Petroleum, or crude oil, is put through a refining process by which the gasoline is distilled out.

3. The method of cooling by water is easy to accomplish.

4. A new car factory will have been constructed by the end of this year.

5. The driver can make the car operate by turning the fly-wheel.

METHODS OF HOLDING TOOLS BETWEEN CENTERS

When machining a piece or work on a lathe it is usually mounted between the lathe centers. Having been mounted on the lathe the work is supported by conical points or the live and dead centers. The work must have centre holes in each and drilled by using a combined drill and a countersink. The size of the centre hole has to be proportional to the weight of the work and the size of the cut to be taken.

The two lathe centers are mounted in two spindles: one the live centre is held in the headstock spindle and turns together with the spindle and the work, the other - the dead centre is held in the tailstock spindle and in most cases does not turn and rubs against the work piece. The point of the dead centre should be hardened to prevent its wearing during the operations performed on the lathe.

Both lathe centers should always be aligned, i. e. the points are to meet when the tall stock with its centre is moved up to the headstock centre.

When works are machined at high speeds or when they are too heavy a dead centre and the work will be heated up so as to cause excessive wear from friction. In such cases so-called running centers are used.

Short parts are usually held in a chuck. This method of holding work is of great importance since it is widely used with lathes. A chuck is a rotating vice which may be attached to the nose of the lathe spindle. There are three important varieties of lathe chucks such as independent jaw chucks, concentric or self-centering chucks or contracting chucks.

Notes and commentary:

1. live centre – центр, що обертається; передній центр

2. dead centre – нерухомий центр

3. countersink - зенкування

4. running centre – обертальний центр

5. vice - лещата

6. independent jaw chucks – патрон з незалежними кулачками

7. concentric chuck - самоцентрований патрон

8. contracting chuck – цанговий патрон

Task 1. Answer the following questions:

1. What is the most widely used method of holding work in the lathe?

2. By what parts of the centres is the work supported while being turned?

3. Where are the two lathe centres mounted on a lathe?

4. What kinds of centres are used on a lathe?

5. Where is the live centre held and how does it operate?

6. Where is the dead centre held and does it turn or not?

7. Where are the short parts held?

8. What main lathe chucks do you know?

Task 2. Find in the text English equivalents for the following words and word combinations:

передня бабка, задня бабка, зенкувати, обертальний центр, лещата, патрон, вмонтовувати, підтримувати, знос, обертати, тертя, машинна обробка, розмір, отвір, вирівнювання, прикріплювати, передній кінець шпінделя.

Task 3. Translate the following sentences:

1. Відомо, що передня та задня бабки вмонтовуються на протилежних кінцях станини верстата. 2. При обробці заготівка встановлюється між центрами верстата. 3. Обидва центри верстата повинні бути вирівняні. 4. Короткі деталі закріплюються в патронах. 5. Існують різні види патронів.

MACHINE-CUTTING TOOLS

The cutting tool is that part of machine which serves for removing material from revolving work. The quality of work depends upon correct selection of cutting tools used for metal-cutting operations.

Cutting tools are made of hardened and tempered steel or alloy metals. All cutting tools are used to perform certain work more efficiently and they may be subdivided into turning tools, shaper tools, boring tools, planing tools, milling tools etc.

These tools having one effective cutting edge along which excess material from the work piece is removed are known as single-point cutting tools. Other tools removing excess material on two or more cutting edges simultaneously are known as multiple-point cutting tools. Each cutting tool consists of a shank for holding the tool in the machine and a tip or cutting edge for removing chips from the work.

The various types of cutting tools differ in shapes and in the angles to which the surfaces of the tools are ground. The cutting tip should be ground by hand or by machine with correct angles on the top face (rake angles) and sides (clearance angles) to a desired shape.

The shape of the tool as well as the proper rake and clearance angles depend upon a large number of factors, such as the specific operations, the material to be cut, and the material from which the tool is made. For efficient operations of the machine, the proper surface speed of the work being machined must be maintained. If the speed is too slow, the jobs take more time than necessary and on the other hand, if the speed is too great, the cutting edge will be worn down too rapidly.

Cutting tolls used for longitudinal turning are subdivided into roughing tools and finishing tools. Roughing tools are applied for roughing or removing the excessive metal from the work. Such tools are usually carbide-tipped and they have a long cutting edge.

Finishing tools are used after the work has been turned with a roughing tool to give accurate size and clean surface to the work being machined. Before starting the cutting operation tools should be clamped in the tool-holder by means of two or more bolts.

Notes and commentary:

1. effective cutting edge - робоча ріжуча кромка

2. single-point cutting tool - різець з дуже тонкою ріжучою кромкою

3. multiple-point tool - різець з декількома ріжучими кромками

4. roughing tools - чорнові різці

5. rake- нахил, кут нахилу, передній кут різця

6. clearance - зазор; просвіт, допуск

7. clearance angle - задній кут

Task 1. Answer the following questions:

1. What is the cutting tool used for?

2. What are cutting tools made of?

3. What kind of work do cutting tools perform?

4. What parts does а cutting tool consist of?

5. What are finishing tools used for?

Task 2. Translate the following sentences:

1. Різці виготовляються із загартованої сталі. 2. Ріжучі інструменти використовуються для зняття металу з деталі. 3. Кожен різець складається з хвостовика і ріжучої кромки. 4. Різні типи різців відрізняються формою і кутом, під яким заточена поверхня різця. 5. Для ефективної роботи верстата повинна підтримуватися відповідна швидкість обробки.

Task 3. Use the following words and phrases in sentences of your own:

turning tool, roughing tools, cutting edge, shank, accurate size, finishing operations, tool-holder, by means of, surface, to machine.

HYDRAULIC SYSTEMS

The simplest hydraulic system is perhaps the hydraulic shock absorber which consists of a pump (piston) and resistance. Another elementary type of system is the hydraulic weighing machine, which consists of a non-continuous pump element (piston or diaphragm) and a pressure gauge.

Other elementary systems consist of a jack, transmission line, and a pump of the non-continuous type without control gear, although valves may still be present for secondary purposes. Systems of this type are used for remote transmission of manual or pedal effort or motion, or for remote transmission of instrument indication. The simplest best known system of this type is the hydraulic brake.

The basic elements of hydraulic systems are: the fluid, the generator element (pump), the transmission element (pipes and connections), the control element (valve or restrictor), the motor element (jack or continuous motor), tank and filter.

The most elementary form of pump can only function as а pump while the piston is moving into the cylinder and acts as a motor while the piston moves back. If non-return valves are added, the inlet valve is connected to a tank and the piston is given a to-and-fro motion, the device becomes a source of continuous supply of liquid, except for interruptions during the suction stroke, which can be avoided by having two or more cylinder and pistons. Thus we obtain a continuous pump.

Notes and commentary:

1. non-return valve - зворотний клапан

2. to-and-fro motion - зворотно-поступальний рух

3. pressure gauge - манометр

4. remote transmission - дистанційна (на відстані) передача

5. manual or pedal effort - ручного або ножного підсилення

Task 1. Answer the following questions:

1. What are the basic elements of hydraulic systems?

2. What is the simplest hydraulic system?

3. What does the hydraulic weighing machine consist of?

4. How can you describe the hydraulic brake?

Task 2. Make up questions to the underlined words:

1. The low-pressure oil for the controlling hydraulic mechanisms is supplied by the additional gear pump.

2. Electrically remote-controlled hydraulic system with a pump and rotary motor operates the feed and rapid traverse of a milling machine.

3. The variable delivery piston pump with axial pistons is intended for controlling the speed of the constant delivery hydraulic motor.

4. With a constant delivery pump the discharge is controlled by throttling the flow.

5. In circuit with variable delivery pumps the cutting speed and the rate of feed can be regulated by reducing or increasing the flow of the fluid.

TUBING, TUBE CONNECTORS AND FLEXIBLE HOSE

The various units of a hydraulic system are connected with some form of tubing or flexible hose. Tubes are joined by means of tube connectors, usually of the same material.

Some of the factors governing the selection of tubing are corrosion, temperature, weight, mechanical strains, abuse, and pressures. Because of its light weight, aluminum-alloy tubing and fittings are used wherever possible.

Fittings are designed to withstand the bursting pressure that the tube of maximum wall thickness will withstand, assuming that the tube and fittings are of similar materials. For general high pressure installations steel tubes and fittings are recommended.

Flexible hose is used to connect hydraulic units between stationary and moving parts. Hoses are made up of varying layers of synthetic rubber, fabric, and wire braid. In installing hoses care must be taken that the hose is free from twists. Under pressure a twist will rotate the hose and loosen the connection, causing failure.

Notes and commentary:

1. tubing - труби

2. flexible hose - гнучкий шланг

3. joined by means of – з'єднані за допомогою

4. the factors governing the selection - чинники, що визначають вибір

5. whenever possible - де тільки можливо

6. the bursting pressure - розривний тиск

7. assuming that - беручи до уваги

8. stationary and moving parts - нерухомі й рухомі частини

9. are made up of - зроблені з

10. In installing flexible hose a care must be taken that the hose is free from twist - При установці гнучкого шланга слід вжити заходи проти скручування шлангу

Task 1. Answer the following questions:

1. How are the various units of a hydraulic system connected?

2. What are the factors governing the selection of tubing?

3. What are fittings designed for?

4. What is the use of flexible hoses?

5. What are hoses made up of?

Task 2. Translate the following sentences paying attention to Passive Constructions, Gerund and Participle:

1. Strength of metals is the property of hard materials to be subjected to the influence of external forces without changing their shape. 2. The ability of a material to take deformation without breaking is known as plasticity. 3. By testing a metal one can define its mechanical properties. 4. This bar is subjected to the action of two sets of external forces. 5. Cutting tools are made of carbon steel. 6. The distance that the tool is set into the work for cutting operations is referred to as the depth of cut. 7. Different kinds of cutting tools are used for metal-cutting processes depending upon the kind of metal being cut.

PLANER, SLOTTER & SHAPER

Planers are essentially used for machining plane surfaces which are larger than can be cut or reached on the shaper. The modern planer with modern electric controls has a high output.

The planer has a reciprocating table which travels beneath a cross bar on which the tool heads are mounted. Normally one or two tool heads are mounted on the cross bar, but additional tools, generally for cutting vertical faces, may be mounted on the columns supporting the crone bar. The usual design comprises two vertical columns between which the table reciprocates. The cross bar is so mounted that it can slide vertically on these columns. All motions for feed or cut take place either by dropping the cross bar, moving the tool head across the cross bar, or lowering the tool holder mounted on the tool head. The first two of these motions are generally power or hand-operated but the last is often hand-operated only.

The table is normally operated by some form of rack-and-pinion of spiral drive. Modern high-speed planers are now fully electrified. The slotting machine may be looked upon as a vertical shaping machine. It machines the internal surfaces of a casting or forging and can do circular work by virtue of its pivoted table. Originally slotters were used for cutting keyways, machining the square holes in such parts as dog clutches and they are still used for this work in small shops.

The work table is usually circular and provided with T-slots for clamping the work. It is mounted on two horizontal slides at right angles to each other and can be moved with either hand or intermittent automatic feed in either direction along them.

It can also be rotated in the horizontal plane about its axis in either direction by hand or automatically. Slotters are usually provided with three or four speeds, obtained either by cone pulley or gear-box.

A shaper is a machine that forms surfaces by successive reciprocating cuts of a tool over the work. The work is stationary with reference to the tool but moves laterally in small steps so that the successive cuts can be made. Although most of the work performed on shapers consists of plane horizontal surfaces, it is also possible to finish vertical and angular surfaces, and, with the proper tools and accessories even curved surfaces may be machined.

The size of a shaper is determined by the longest stroke of the ram. Shapers are driven by belt from a countershaft, by direct connected motor, or by hydraulic power.

Notes and commentary:

1. planer - поздовжньо-стругальний верстат

2. plane surface - плоска поверхня

3. high output - висока продуктивність

4. reciprocating table – стіл, що рухається назад і вперед

5. cross bar - поперечина

6. tool heads - інструментальні головки

7. motions for feed or cut take place - рухи для подачі або обробки ріжучим інструментом відбуваються

8. rack-and-pinion drive - зубчато-рейковий привід

9. spiral drive - привід гвинтовими колесами

10. may be looked upon - може розглядатися

11. by virtue of its pivoted table - завдяки повороту стола на осі

12. cutting keyways - прорізання шпонкових канавок (пазів)

13. dog clutch - кулачкова муфта

14. T-slots for clamping the work - Т-подібні пази для затискання деталі

15. in either direction - у будь-якому напрямі

16. in the horizontal plane about its axis - у горизонтальній площині навколо своєї осі

17. cone pulley - ступінчастий шків

18. by successive reciprocating cuts of a tool over the work - послідовним зворотно-поступальним зняттям металу ріжучим інструментом, що переміщується над деталлю

19. in small steps - малими подачами

20. plane horizontal surfaces - плоскі горизонтальні поверхні

Task 1. Make the following sentences refer to the past and future:

1. Some lathes can do over two hundred various operations.

2. The energy of water is converted into mechanical energy.

3. We must cut different metals at different speeds.

4. We can harden high carbon steel by heating it to a certain temperature and then quickly cooling in water.

5. This steel must be used for automobile parts such as gears, and

Task 2. Put questions to each part of the following sentences:

1. Drilling apparatus and techniques have undergone wide improvements.

2. Various methods have also been applied to collect supplementary information.

GЕNERAL DESCRIPTION OF LATHES

A lathe is a machine tool for producing and finishing surfaces of work-pieces. The machine is designed to hold and revolve a work around an axis of rotation so that it may be subjected to the action of a cutting tool moving in a horizontal plane through the axis of the work. When the cutting tool moves in a longitudinal direction or parallel to the axis, the operation is known as " turning"; when it moves in a transverse direction, it is known as " facing". In addition to turning and boring, which the machine is designed for, many other operations, such as drilling, threading, tapping, and by employing special adapters grinding and milling, may be performed on a lathe.

Modern lathes are highly efficient, accurate and complex devices, capable of doing a great quantity and variety of work. Lathes are made in a wide variety of types and sizes, from the small precision lathe found in watch repair shops to the immense machine.

The lathe consists essentially of a bed, headstock, tailstock and saddle.

The Bed. The main casting of the lathe is called the bed, and usually consists of a good quality grey iron casting of rigid design. It is provided with accurately machined ways, on which slides the saddle and the tailstock, and on which the headstock is located and bolted. The ways may be flat or of inverted V-type. Various lugs and brackets are integral with the casting for the mounting of other parts as required on the machine.

The headstock is located true with the ways and bolted rigidly to the bed at the left-hand end. It carries the lathe spindle and back gearbox if the lathe is of the all-geared head type. The spindle is mounted in two large plain bearings, capable of adjustment, and provided with thrust washers to prevent end play. The nose of the spindle is provided with an external thread and register for attaching a face plate or a chuck back plate and a taper bore for the insertion of a centre. On the other end is mounted a gear to drive a train of wheels for driving the screw and the feed shaft.

The tailstock consists of a casting fitted to the bed and capable of being firmly clapped to it at any position along its length. The casting is bored for a sliding sleeve which is moved axially by a hand-wheel at the right-hand end.

The saddle consists of a casting designed to carry the tool post slide or slides, and is fitted to the ways of the bed so that it may slide along it without lateral movement. The front of this casting, called the apron, carries the gearing and controls for traversing the saddle towards and away from the headstock. The cross slide is mounted on the top of the saddle and must be at right angles to the bed.

On the cross slide is mounted the tool slide. There are four main types of headstocks, which are classified by the method of power application. They are the step-cone head, the geared head, the built-in motor-drive head, and the full hydraulic-drive head.

The step-cone type of lathe is driven by a belt from an overhead countershaft, which has a step-cone pulley corresponding to the step cone on the lathe. A geared-head lathe is driven by a constant-speed motor usually located in the base of the lathe, or it may be driven by belt on a single pulley. A direct motor-drive geared head has the motor built directly into the headstock.

A recent design of lathes uses a variable-speed hydraulic motor as a source of power. The motor is belted to the head by means of V-belts. The hydraulic motor has a speed variation from zero to maximum speed by an infinite number of steps. Any working speed can be obtained by merely turning a dial that regulates the hydraulic motor.

Notes and commentary:

1. modern lathes - сучасні токарні верстати

2. accurate and complex devices - точні та складні прилади

3. precision lathe - прецизійний токарний верстат (для точної обробки)

4. main casting of lathe is called a bed - основний каркас токарного верстата називається станиною

5. accurately machined ways - точно оброблені напрямні верстата

6. on which slide the saddle and the tailstock – по яких рухаються полозки та задня бабка

7. of inverted v-type - форма перевернутої літери V, клиноподібний

8. are integral with the casting - зроблені відповідно до станини

9. is located true with the ways – розміщується паралельно до напрямних

10. at the left-hand end – з лівого краю

11. all geared head type - токарний верстат із передньою бабкою з одношківним приводом та коробкою швидкостей

12. the lathe spindle - шпиндель токарного верстату

13. plain bearings – підшипники (вальниці) без вкладиша

14. thrust washers - опорні шайби

15. to prevent end play - запобігти подовжньому люфту

16. external thread - зовнішня різьба

17. face plate - планшайба

18. chuck back plate - диск універсальної планшайби

19. taper bore - конусне розточування

20. to drive a train of wheels - приводити в рух систему колес

21. lead screw - ходовий гвинт

22. feed shaft - вал подачі

23. firmly clamped to it - міцно прикріплений до нього

24. at any position along its length – у будь-якому місці вздовж всієї її довжини

25. sliding sleeve - ковзаюча втулка, висувна піноль

26. to carry the tool post slide - переміщувати полозки, що тримають різець

27. lateral movement - поперечний рух

28. towards and away from the headstock – у напрямку передньої бабки та назад

29. step-cone head - передня бабка зі ступінчатим приводом

30. geared-head - передня бабка з постійною швидкістю ременя та коробкою швидкостей

31. built-in motor drive head - передня бабка з вмонтованим мотором

32. single-pulley - одношківний

33. V-belts – клинові ремені

34. infinite number of steps - нескінченна кількість ступенів

35. by merely turning a dial – простим поворотом шкали

36. turning – обробка на токарному верстаті

37. facing – обробка (обточка) торцівки

38. boring – розточка, висверлювання, розсверлювання

39. drilling - сверління

40. threading – нарізування різьби мітчиком

41. tapping – нарізання різьби

42. grinding - шліфування

43. milling – фрезування

44. bench-lathe - верстат

45. turret lathe – револьверний верстат

Task 1. Answer the following questions:

1. What is a lathe? What is the lathe designed for?

2. What is facing?

3. What operation is known as turning?

4. What kind of operations can lathes perform?

5. How are lathes classified?

Task 2. Find in the text English equivalents for the following words and word combinations:

горизонтальна площина, вісь обертання, нарізування різьби, шліфування, свердлення, конструкційні особливості, деталь обробки, верстак, розточування, в поперечному напрямі, точність, револьверний верстат, обробка (обточування) торцівки.

Task 3. Translate the following sentences paying attention to the Participle Constructions:

1. A lathe being a machine tool, it can perform different operations. 2. Numerous experiments having been carried out, the design of the new grinding wheels was approved. 3. Clutch constructions being based on the positive-action and friction principles, couplings are made in two main types: rigid and flexible. 4. The automatic lathe being designed by a group of young engineers works with great precision. 5. Moving with great speed the motor is heated.

ANNEX 1

Reading Techniques

Skimming is a technique suitable for scientific texts as well as for general texts. This is defined as the search of main ideas using only the first and last paragraphs to obtain a general view of the text. When you are working with scientific texts applying this technique can be easier since this type of literature usually contains topic headings, abstracts or summaries that might come in handy for the reader. Another advantage of a scientific text is that they are usually written in block of information grouped in paragraphs. In this case the best alternative is to read the first sentence of each paragraph. It is important to note that this technique is used not as a short cut to reading the whole text. It does not mean that you can simply read the first and last paragraphs and that you can understand everything. This technique is used to help you get n idea of what you are about to read. Skimming is like having a map before entering a city. It is less likely that you get lost if you have previous information.

Scanning. When students face a new text they tend to read word by word. This way of reading affects the general understanding of the passage and the time taken to finish the reading can be too long for the final results. The students can end up reading every word very well but in the long run the idea of what they have read is lost. To avoid this loss of time and effort a reader can use Scanning to help him or her. Scanning consists on running your eyes down the text, searching for important or key words, as well as the most outstanding facts. Scanning can be a preliminary step in reading because with it you can locate new terms, look them up in a dictionary or a glossary and save time when you actually begin to read. The process of Scanning can not take more than a couple of minutes. After that you must decide which terms are the most important and which part of the reading deserves more attention. Do not forget that this is only a comprehension technique designed to help you get into the reading, in order to interpret the authors intentions and ideas it is important to read the whole text and the analysis of it must be done with a little bit more detail.

Using Context. Most of the times we are faced with reading something just then, at that precise moment. In the real world you can not be too prepared to read a text. In many cases you simply do not have the time to use a dictionary or to apply a given technique. It is only you and the text. This is when understanding context can come in handy. Context can defined as the elements that surround a term and help clarify its meaning. The first thing to do when taking advantage of context is recognizing the grammatical category of the word we are trying to understand of define. Is it an adverb, an adjective, a verb or a noun? English grammar can give us some tips to know exactly what kind of word we are dealing with, for example:

If the word ends in ly and is located after a verb it is likely that you have an adverb.
If the word is before a noun and is not pluralized it can be an adjective.
If the word is after a personal pronoun or a noun it might be a verb.
If the word has a definite or indefinite article or it is pluralized it is possible to be a noun.

ANNEX 2

Writing Techniques

The Paragraph. A paragraph is a basic unit of organization in writing in which a group of sentences develops one main idea. The number of sentences a paragraph contains is not important. It can be as short as one sentence or as long as nine sentences, the most important thing is that the idea stated at the beginning is clearly developed.

Parts of a Paragraph. Three essential parts compose any paragraph: a topic sentence, supporting sentences and a concluding sentence.

1. Topic Sentence: it states the main idea of the paragraph. It contains the name of the topic that is to be carried out. This sentence has to be precise, but avoid telling everything in the first sentence or your reader will lose interest. The topic sentence serves to limit the topic to one or two areas that will be discussed entirely in the space of one paragraph. The area is what we call the controling idea.

2. Supporting Sentences: they come after the topic sentence, making up the body of a paragraph. they help develop the topic sentence. It means that these sentences explain the topic by giving reasons, examples, facts, statistics, and quotations.

3. Closing Sentences: itґs the last sentence in a paragraph, it indicates that the paragraph is ending and sums up important points to remember or reprises the main idea. You write it restating the main idea of a paragraph but using different words.

In adition to the three parts of a paragraph, a good paragraph also needs two important elements: unity and coherence. Unity: it means that in your paragraph you discuss one and only one main idea which is stated in the topic sentence and then developed by the supporting sentences. Coherence: it means that your paragraph is easy to read and understand because:

your supporting sentences are in logical order
your ideas are connected by the use of a appropriate transition signals.

How to Write an Essay. To define the essay briefly, one can say that it is a piece of writing usually short (3 to 10 pages), written in prose, and that may be on any subject. The essay is generally based on other people's statements. In the essay you can include your personal opinion, and some examples to illustrate your point of view. It is written about one topic, just as a paragraph is. However, the topic of an essay is too long and too complex to discuss it in one paragraph. Therefore, you must divide the topic into several paragraphs. In general, essays have three basic parts: introduction, body and conclusion.

The Introduction. It is the first section of your essay. This makes it extremely important, because first impressions are often lasting ones. It consists of two parts: a few general statements about your subject to attract your reader's attention, and a thesis statement, that states the specific subdivisions of your topic and/or the " plan" of your paper. The introduction then, begins with remarks to interest people. As it progresses, it should present general ideas or facts to orient the reader. Then, it will narrow its focus, and move from general to specific facts smoothly and logically.

The body Paragraphs. They are the longest section of you essay. In a short essay there are usually three body paragraphs, each one considering in detail one aspect of the essay's controlling idea. This is called a three-point essay. At the beginning of each of your support paragraphs, there is a topic sentence that tells what the rest of your text is going to be about. This sentence should direct your readers back to the controlling idea and indicate which aspect of it you are going to discuss. Once you present your topic, you need details and facts to support it. It is not enough to state your position; your reader needs to be convinced that your point of view is valid an accurate. There is not any rule that determines how long a body paragraph should be. The more relevant detail you can bring in to support your topic sentence, the clearer your points will be.

The Conclusion. The ideas in this part must be consistent with the rest of your essay. In it, you should restate the controlling idea. This restatement is usually more effective when it is located at the beginning of the conclusion. It reminds your public about the major points you were trying to make, and it indicates your essay is about to end. Many writers like to end their conclusion with a final emphatic sentence. This strong closing statement will make your readers think about the implications of what you wrote. You do not introduce your points in your conclusion.

Transitional Signals can be compared to traffic signs. They are words that tell you to go forward, to turn, to slow down and to stop. Better said, they help the reader when to you are giving a similar idea, an opposite idea, an example, a result, or a conclusion. As a writer it is important to use these types of words to help you follow your ideas coherently.

Types of Transitional Signals. Transition words can be classified taking into account they type of help they might offer a writer. They can be classified in the following types:

1. Words that Show Addition. They aid the writer when he or she wants to present two or more ideas that continue along the same line of thought. Some common adition words are: and, also, another, in addition, moreover, first of all, second, third, furthermore, finally.

2. Words that Show Time. They indicate a time relationship. They tell us when an specific event took place in relation to another. Some of these words are: First, then, often, since, next, before, after, soon, as, now, until, previously, while, during, immediately, frequently.

3. Words that Show Contrast. They signal a change in the direction of the writer's thought. They tell us a new idea will be different in a significant way from the previous one. Some contrast words are: but, however, yet, although, in contrast, instead, still, in spite of, despite, on the other hand, on the contrary.

4. Word that Show Comparison. These words are used when a writer wants to point out a similarity between two subjects. They tell us that the previous idea is similar to the next one in some way. Some words that show comparison are: like, as, just like, just as, in like manner, equally, similarly, in a similar fashion, in the same way.

5. Words that Show Illustration. These words are used if you as a writer want to provide one of more examples to develp and clarify a given idea. They tell us that the second idea is an example of the first. Some illustration words are: for example, for instance, as an illustration, to illustrate, such as, to be specific, including.

6. Words that Show Location. Location transitions show a relationship in space. They tell us where something is in relation to something else. Some of these words can be: next to, in front of, in back of, below, between, inside, outside, opposite, on top of, across, beneath, in the middle of, on the other side, at the end of, ahead of, over, under, behing, near, far.

7. Words that Show Cause and Effect. These types of words are useful if an author wants to describe a result of something. They tell us what happened or will happen because something else happened. These type of words are: because, if... then, as a result, consequently, accordingly, therefore, since, so.

8. Words that Summarize or Conclude. These types of words are used when the idea that follows will sum up the entire writing or a final statement will be written as a conclusion. These words are: in summary, in conclusion, in short, all in all, in brief, in other words, on the whole, to conclude, to sum up.

Capitalization Rules. We use a capital letter in the following cases:

1. First words. Capitalize the fist word of every sentence and of a quotation.

2. Personal Names. Capitalize the names of people including initials and titles of address, family words if they appear alone of followed by a name. (Let's go, Dad. Where's Grandma? ). Capitalize names of God. (Allah, Jesus Christ). Do not capitalize family words with a possessive pronoun or article. (My uncle. An aunt)

3. Place Names. Capitalize the names of countries, states, provinces, cities, lakes, rivers, islands, mountains (Mexico, the Amazon, Lake Ontario).

Do not capitalize the names of seasons (summer, spring, fall, winter)

References:

1. Большой политехнический словарь: В 2-х т. - М., 1997

2. Eric H. Glendinning, Norman Glendinning - OXFORD English for Electrical and Mechanical Engineering, Oxford University Press, 1995

3. M. Young, The Technical Writers Handbook. Mill Valley, CA: University Science, 1989

4. Automotive Engineering - on-line technical magazine (www. ae-plus. com)

5. Engineering (Workshop) Lindsay White, Oxford University Press, 2003

6. Popular Mechanics – technical magazine (www. popularmechanics. com)

7. Professional Engineering – (www. profeng. com)

8. Prof. Engineering - on-line technical magazine for professionals (www. professionalcareers. net)

9. Publishing of the Institution of Mechanical Engineers - Journal of Mechanical Engineering Science

10. Publishing of the Institution of Mechanical Engineers - Journal of Multi-body Dynamics

11. Publishing of the Institution of Mechanical Engineers - Journal of Engineering Materials and Technology

12. Publishing of the Institution of Mechanical Engineers - Journal of Fluids Engineering

13. Publishing of the Institution of Mechanical Engineers - Journal of Mechanisms and Robotics

14. Web Resources: www. science-library. com. ua, www. scienceworld. com,

www. tech-libruary. com. ua, www. wikipedia. com.

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