3. True or false statements.

1. Welding processes can be applied to a wide variety of metals.

2. Welding processes are not used in space.

3. The process is commonly used in industry, especially for large products.

4. It is widely used in open-air applications.

5. Gas welding process was by Russian cosmonauts in 1969 in Space.

4. Listen to the text once again and answer the following questing:

1. What processes are commonly used in a wide variety of conditions?

2. Where are welding processes used?

3. When did the welding attempt by Russian cosmonauts.

4. What methods of welding are used in Space?

V. Communicative skills.

Topic for discussion. The main application of joints of machine elements in mechanical engineering.

Unit 12 Topic: Transmission machine parts

1. Pre-reading tasks

1. You will read a text about rotary motion drives. Do you know the members carrying rotating parts?

2. Read and memorise the following words and word-combinations in their specialized meanings.

1. to transmit – трансформувати, передавати

2. rotary motion drives – механізми обертаючого руху

3. intermediate – проміжний

4. substantial – щільний

5. utilize – використовувати

6. friction – тертя, зчеплення

7. worm – винтовий

8. torque – пусковий момент

9. pivot - повертатись, шарнір

10. journal – цапфа

11. shaft – стержень, ручка

12. axis – вал, вісь

2. Read and translate the following text into Ukrainian. Rotary Motion Drives

Transmission of energy from one machine to another or from one member of a machine to another is effected by means of various intermediate mechanisms called drives.

The most common are the rotary motion drives. This is attributable to the substantial advantage of uniform rotary motion over reciprocating motion.

Modern machines utilize mechanical, hydraulic, pneumatic and electric drives. This course in machine design deals with the parts of mechanical drives only.

Mechanical drives may be classified as follows:

according to the physical conditions of transmission of motion: by friction (friction, belt and rope drives); and by engagement of two members (gear, worm and chain drives);

according to the method of linking the driving and driven members: drives with direct contact between the driving and driven members (friction, gear and worm, drives); drives with an intermediate link between the driv­ing and driven members (belt, rope, chain drives).

Each transmission mechanism comprises two basic shafts, namely the driving (input) shaft and the driven (output) shaft.

The members to which power is transmitted from the driving members are called driven members.

Multistage drives have intermediate or idler shafts between the driving and driven shafts.­

Axles and shafts

Members carrying rotating parts (pulleys, gears) are called axles or shafts. Axles and shafts are distinguished according to the conditions they work under. Axles, support­ing the rotating parts, do not transmit torque and are subjected to bending stress only; shafts, which like axles are supporting members, transmit torque and are subjected to bending and to torsional stresses.

The portions of axles and shafts located within the bear­ings are referred to as journals. The journals located at the shaft ends are termed end journals, whereas those between them are called neck journals.

The butt ends or intermediate shoulders of a shaft or axle, which bear against a fixed support and prevent axial displacement are called pivot journals or collars. The pivot journals can be of a flat, spherical or conical shape.

From the viewpoint of design axles can be divided into two main groups:

1. Axles rotating in the bearings together with the members rigidly fixed to them.

2. Stationary axles which support members rotating on them.

Shafts are classified as solid and hollow, straight and cranked, with a variable shape of the geometrical axis (flexible wire shafts, and arti­culated).

As a rule, axles and shafts are designed as bars consisting of a number of cylindrical sections of different diameters.

3. Find the answers to the questions:

1. What is called drives?

2. How may mechanical drives be classified as?

3. What does each transmission comprise?

4. Multistage drives have intermediate or idler shafts between the driving and driven shafts, haven’t they?

5. Which members carrying rotating parts do you know?

6. Which groups of design axles do you know?

4. Complete the sentences:

1. ... are the rotary motion drives.

2. Modern machines utilize ... .

3. Each transmission mechanism comprises ... .

4. Axles and shafts are ... .

5. The portions of axles and shafts located ... .

6. The shafts are classified as ... .

5. Match the following English words and word-combinations.

1. drive a. тертя, зчеплення

2. friction b. сила

3. force c. сплайн, паз

4. dimension d. підкладка, втулка

5. belt e. приводити в рух; привід

6. shaft f.розмір, вимір, обсяг

7. liner g. підшипник

8. spline h. ручка, стержень

9. cast iron i. пояс, ремінець

10. bear j. чавун,відливка з чавуну

6. True or false statements:

1. Each transmission mechanism comprises two basic sliding keys.

2. Multistage drives have back bolts between the driving and driven shafts.

3. Members carrying rotating parts are called the gear.

4. The pilot journals can be of a flat, Spherical Shape.

5. The parts carried by the axle or shaft are secured to them by means of keys, Splines.

II Retell the text “Rotary Motion drives”.

III Rendering.

1. Read the text and translate it into Ukrainian using new words in their specialized meanings below.

1. couplings – зв’язування, з’єднування

2. clutches – змичка, затискувати

3. attach – прикріплювати, прив’язувати

4. safety – запобіжний, безпека

5. sleeve – вікель, трубка, муфта

6. shear – зріз

7. pin – болт