Figure. All Geared Headstock Centre Lathe

1 — surfacing hand traverse; 2 — auxiliary slide; 3 — dead; 4 — centre tailstock barrel; 5— barrel locking lever; 6— tailstock; 7— tailstock clamping; 8— tailstock transverse adjustment; 9 — bed; 10— swarf tray;

11 — screwoutting lever; 12 — surfacing feed lever; 13 — sliding feed lever; 14 — sliding hand traverse; 15— lead screw; 16— reversing shaft feed shaft or lead screw lever; /7 — push button starter; 18— gear-box feed selection lever; 19— norton type; 20— change to feed shaft; 21 — guard speed; 22— spindle; 23 — constant speed driving pulley; 24 — speed change levers; 25 — gear change headstock; 26 — starting clutch lever; 27 — driving or catch plate; 28— live centre; 29— tool post; 30— cross slide; 31 — saddle; 32— rack; 33 — lead screw; 34 — apron; 35 — reversing shaft lever; 36 — feed shaft

The saddle consists of a casting designed to carry the tool post slide or slides, and is fitted to the ways to 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 fortraversing 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.

The tool slide is mounted on the cross slide. There are four main types, of headstock, 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-conepulley corresponding to the step cone on the lathe.

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

Exercise 1.1. Find the Russian equivalents for the following word combinations:

capable of doing a great quantity and variety of work; the main casting of the lathe; in a wide variety of types and sizes; on which the saddle and the tailstock slide; the mounting of other parts; the headstock is bolted; is bolted rigidly to the bed; is mounted in the plain bearings; the nose of the spindle; is provided with the external thread; for attaching a face plate; is moved axially by a hand wheel; is bored for a sliding sleeve; without lateral movement; for traversing the saddle towards and away

from the headstock; by the method of power application; pulley corresponding to the step cone on the lathe; built directly into the headstock.

ролик (шкив), соответствующий ступенчатому приводу токар­ного станка; по способу применения силы (мощности); встроен­ный в переднюю бабку; для крепления планшайбы; с наружной резьбой; способны выполнять разнообразные виды работы вы­сокого качества; передняя бабка крепится болтами; высверлива­ется с помощью скользящей втулки; движется вокруг своей оси с помощью ручного маховика без поперечного движения; за пере­мещением башмака к передней бабке и обратно; по которой скользит башмак и задняя бабка; главная составная часть токар­ного станка; в широком разнообразии типов и форм; крепление других деталей; прочно крепится к станине; крепится в подшип­никах без вкладышей; передняя часть шпинделя.

Exercise 1.2. Answer the questions:

1. What are lathes?

2. Are there a wide variety of types and sizes of lathes?

3. What parts does the lathe consist of?

4. What is the bed?

5. What is it provided with?

6. What does the bed consist of?

7. What is the headstock?

8. What does the headstock consist of?

9. How are noses of spindle mounted?

10. What does the tailstock consist of?

11. How is a sliding sleeve moved?

12. What does the saddle consist of?

13. Where is the cross slide mounted?

14. What are four main types of lathes?

15. What are features of lathes?

16. What is a source of power in a recent design of lathe?

    7*

    99

Exercise 1.3. Complete the sentences:

1. Lathes are made from ...

2. The lathe consists of...

3. ... consists of a good quality gray iron casting of rigid design.

4. ... carries the lathe spindle and a back gear-box.

5. The saddle, the tailstock and the headstock are bolted on ...

6. The spindle is mounted in ...

7. A gear is used to drive the lead screw ...

8. The tailstock is bored for ...

9. ... slides along without lateral movement.

10. The cross slide is mounted ... must be at right angles to the bed.

11. A direct motor-drive geared head has ...

12. The front of the saddle is called ...

Exercise 1.4. Translate into English:

1. Токарные станки — сложные устройства, обрабатывающие разнообразные детали.

2. Токарные станки состоят из станины, передней бабки, задней бабки и опоры.

3. Токарные станки бывают различных типов и размеров.

4. Передняя бабка крепится к станине станка.

5. Передняя часть шпинделя обнажена внешней резьбой для крепления планшайбой.

6. Каркас основы перемещает резцедержательные салазки.

7. Салазки на верху башмака находятся под прямым углом к станине.

24. Text A

LATHE

Memorize the pronunciation of the following words:

lathe [leid] — токарный станок bed [' bed] — станина станка headstock [ 'hed, stok] — передняя бабка tailstock [' teilstok] — задняя бабка

apron ['eipran] — фартук, основная поворотная доска резцовой каретки

carriage [' kasridj] — каретка станка to traverse [' traeva: s] — пересекать; поперечина to clamp [' klaemp] — крепить, закреплять spindle [spindl] — шпиндель

to maintain [,men'tein] — поддерживать, обслуживать, содержать

Word combinations for connecting reading:

linear feed motion — прямолинейное движение подачи feed gearbox — коробка подач speed gearbox — коробка скоростей

TEXT

The lathe is the most general and useful of all machine-tools and is used in producing many types of machine parts.

In machining operations on lathes, the work is rotated, while the cutting tool has a linear feed motion.

Although there are many types of lathes employed in industry, they have many units and parts in common. The principle units of an engine lathe are the bed, headstock, tailstock, feed gearbox, apron andcarriage. All the principle units of the lathe are mounted on the bed. The latter has ways along which the carriage and tailstocktraverse. The work isclamped and rotated by the headstock which contains thespindle andspeed gearbox. In all lathe work it is most importantto clamp the work and the tool as firmly as possible.

The separate parts and mechanisms of the lathe can be maintained in proper operating condition only by attentive care.

Exercise 1.1. Find the Russian equivalents for the following word combinations:

the most useful of all machine-tools; the work is rotated; in producing parts; are mounted on the bed; is rotated by the headstock; to maintain in proper condition; contains spindle.

деталь вращается; содержит шпиндель; содержать в особых условиях; крепятся на станине; вращается при помощи передней бабки; в изготовлении деталей; наиболее используемый из стан­ков.

Exercise 1.2. Answer the questions:

1. What machine-tools are the most general?

2. Where is lathe used?

3. What are the main parts of an engine lathe?

4. Where are all the principle units of the lathe mounted?

5. What does the headstock contain?

6. When is the headstock rotated?

Exercise 1.3. Find the wrong statements and correct them:

1. Lathe is used in manufacturing many types of machine-tools.

2. The principle units of an engine lathe are the bed, headstock, speed gearbox, feed gearbox, apron and carriage.

3. The work is rotated by the tailstock.

4. The lathe parts are clamped on the bed.

5. The headstock contains the carriage and feed gearbox.

Exercise 1.4. Complete the sentences choosing the appropriate variants:

1. The cutting tool has ...

2. In machining operations on lathes the work is ...

3. The work is clamped and rotated by ...

4. The spindle and speed gearbox are the parts of...

headstock; linear feed motion; rotated.

Exercise 1.5. Translate into English:

1. Токарный станок используют в производстве деталей.

2. Прямолинейное движение подачи режущего инструмента обеспечивает вращение детали.

3. На станине крепятся основные части токарного станка.

4. Деталь вращается при помощи передней бабки.

5. Передняя бабка содержит шпиндель и коробку скоростей.

6. Станина и задняя бабка — это основные части токарного станка.

24. Text С