4. Choose the right statement:

1). Couplings normally form permanent or semipermanent connections … , while clutches are associated with rapid engagement.

a)between tubes;

b) between shafts;

c) between plates.

2). Couplings for high-speed and / or high-power machinery are almost

exclusively of … type.

a) rigid;

b) flexible;

c) the gear (or dental).

3). When it is necessary to dis­connect or connect machines while in operation … coupling can be used.

a) a jaw-type;

b) a rigid type;

c) a permanent.

5. Fill in the gaps.

Couplings are machine 1)____ used to join one shaft to another, which are needed because of specialized 2)____ of the machine – for example, 3)____ or servicing. The coupling of an electric motor 4)____ a wa­ter pump or a gear box may transmit power.

1). a) elements, b)parts, c) details.

2). a)functions, b)operations, c)problems.

3). a) installation, b) repairing, c) assembling.

4). a)servicing, b) driving, c) managing .

6. Complete the sentences.

Couplings normally 1)____ permanent or semipermanent connections between shafts, while clutches are associated with rapid 2)____. Solid couplings 3)____ of rigid flanges on each shaft, 4)____ solidly together to form a continuous stiff shaft. Their use is favored when it is 5)____ that the connected machines act as a single unit (for example, the rotor of a motor or generator may be used as the flywheel of a 6)____ engine or compressor) or to

reduce over-all length (such as an overhanging blower) or to 7)____ bearings (by 8)____ components together such as a gear pinion to a turbine). Shaft 9)____ can result between the two shafts,10) ____bearing loads. Jaw-type coupling is operated only when the two shafts are 11)____ at the same speed.

c) form, f)consist, e) bolted, g)desired, i)reciprocating, h)eliminate,j) coupling, k) misalignment, d) engagement, m)running l)increases.

7. Group the synonyms.

1)act, 2)result, 3)made of, 4)apply, 5)link, 6)fast, 9)use, 10)fasten, 7)carry, 16)consist of, 11) join, 20)quick, 19)composed of, 12) operate, 17)attach, 8)bear, 18)rapid, 13)deed, 14)action, 15)consequence.

UNIT 8

1. Learn the notions and their definitions.

Washer A flat disc, ring of metal, rubber etc., locking a nut in a place.

Shaft A machine part supporting and confining a moving part.

Gear A toothed wheel designed for being engaged with another one or with a warm.

Spur Gear A gear with straight teeth parallel to the axis.

Pinion The smaller member of a pair of gears or the smallest gear of a series; gear is used to designate the larger member.

Helical Gear A gear with teeth cut in the shape of a helix

Herringbone Gear A helical gear with two sets of teeth at equal

but opposite angles to each other.

Bevel Gear A gear with teeth slanted at an angle to the plane of the wheel itself.

Worm Gear A mechanism consisting of a gear that meshes with a worm, a screw with helical teeth.

Sun-and-Planet Gears An arrangement in which a smaller gear (the planet) rotates around a larger gear (the sun).

Casing, housing A machine covering

Bearing That part of a machine which supports parts in relative Motion.

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