Engineering Components. Lathes and Machines. Materials

One of the most common forms of component ⁽¹⁾ is perhaps the bolt. It is

used for fastening together any two or more parts of a machine which may require dismantling quickly in any emergency, such as in repair work. The body of a bolt is called the shank, one end of which has ahead, while the opposite end is screw-threaded to accommodate a nut. A bolt is often fitted with a plain round washer, ⁽²⁾ which forms a sort of cushion between the nut and the workpiece which it secures.

By their shapes bolts may be divided into square-headed, cup-headed, countersunk head, etc. Bolt nuts are known as hexagonal, square, wing-nuts, and others.

To prevent nuts from working loose there exist lock-nuts, split pins, etc. To fix together some articles permanently rivets or welding may be used.

Another kind of component used to locate and secure an object ill position is а key. Usually the key is inserted between а shaft and а wheel in order to retaill the latter in а fixed position on the shaft. A shaft is intended to mount pulleys, gear wheels, etc. by forming an axle upon which they can rotate. If is usually of solid cylindrical shape, but may also be of hollow construction. А thin or lift type of shaft is often called a spindle.

Among the shafts the most typical are crankshafts, camshafts, splined shafts, and so on.

Components on which shafts are supported, or mounted, in order that they may rotate freely are called bearings⁽³⁾, journals, or pedestals. There are many types of bearings, varying from plain cast iron to those of the ball or roller pace pattern.

А typical ball bearing consists of the outer race, inner race, balls, and ball cage.

 

Power Transmission Systems. А mechanical drive is а mechanism intended to transmit power from the prime mover to the machine. By the mode of transmitting motion from the prime mover mechanical drives fall into the following types:

(а) transmission by friction: with direct contact(friction drives) or а flexible connection (belt drives);

(b) transmission by mesh: with direct contact (toothed and worm gears) or with а flexible connection (chain drives).

Components of almost аll machines used to transmit power both to and within а machine and connect shafts are called couplings and clutches.

Couplings may be divided into two groups: those of the fixed or rigid class, and those of the flexible type.

Rigid couplings may be exemplified by claw-type couplings, flanged couplings, universal couplings, etc. The most widely spread flexible couplings are disc-type and hydraulic-type ones. А clutch is а kind of coupling, by means of which two shafts ⁽⁴⁾ may be connected or disconnected at will.

The most typical clutches are disc-type or cone-type friction clutches. To prevent any serious damage of а machine due to overloading safety clutches are used.

А drive may also be formed by a series or two or more; toothed wheels, or gears, which are meshed together to make a gearing.

The most common types of gears are spur-type gears, bevel gears, bevel gears, worm gears, etc.

Lathes and Machines. Suppose а roughly shaped cylindrical steel bar is rotated, its ends having been secured between two horizontal pivots (called centers). Now if а hardened steel-cutting tool is pressed against the bar's surface and is moved at а uniform speed to and fro length-ways it will cut evenly into the bar, thereby removing its surface. Here we have the elementary principle of а lathe as used for plain machining work, or turning. А lathe consists of а strong framework, usually of east iron, its top is named the bed. Mounted on the bed is а tool-s1ide rest, which carries the tool-post (or holder) and is free to slide on  its

base across the. The workpiece is held in the lathe between two supports, known as headstock and tailstock respectively.

The headstock comprises а spindle, which is usually rotated an electric motor and gearing. The tailstock does not rotate, but holds one end of the workpiece

In addition to plain lathes, several other kinds of lathes are widely used: screw-cutting, turret lathes, etc. The cutting tools also vary considerably, but for plain turning the chief types are the roughing, facing, and parting tools.

There are some machines in which the tool is fixed and the “work” is moved to end fro against it in a horizontal plain.

 

They are: the planning machine (or planner), milling machine, grinding machine, etc.

4. Переведите письменно:

Инструмент – tool, instrument

1. Для того чтобы изготовить молоток, достаточно использовать слесарные инструменты. 2. Для того чтобы вычертить чертеж молотка, необходимы чертежные инструменты.

Сцепление – engagement, coupling, clutch, traction

1. Прежде чем включить скорость на автомашине, необходимо сперва выключить сцепление. 2. Сцепление в передаче нарушилось из-за повреждения шпонки. 3. Колеса машины буксуют из-за недостаточного сцепления с грунтом. 4. Если обеспечить сцепление этих двух шестерен, машина будет хорошо работать. 5. У автомобиля в сцеплении испортились пружины, сцепление дисков ослабло, и он не мог сдвинуться, хотя сцепление с грунтом было хорошим.

     Передача – transmission, broadcast, parcel, drive, gearing

1. Силовая передача в этой машине имеет большие потери на трение. 2. Смените масло в корпусе червячной передачи. 3. О каких событиях сообщалось в этой передаче? 4. Цепная передача есть разновидность силовой передачи. 5. Больному принесли передачу.

Ось – axis, axle, spindle, pin, pivot, shaft

1. Ось шарнира сработалась. Замените ее. 2. Задняя ось требует смазки. 3. Ось вращения заготовки не совпадает с ее центром. 4. Звонок не звонит, так как погнулась ось молоточка (hammer) звонка. 5. Промежуточная шестерня сидит на короткой оси. 6. Hеподвижная ось несет несколько шкивов.

     Pin – шпилька, штифт, чека, шплинт, шпиль, пробойник, чертежная кнопка, палец (шатуна)

1. This catch pin secures the dashing on the axle. 2. Give me some drawing pins. 3. Fix this nut with a split -pin. 4.The safety pin safeguards the grenade against selfdetonation. 5. Piston pin knocking is the characteristic noise of a piston engine being overloaded. 6. The tower pin was used as a lightning conductor. 7. Prick this metal sheet with a pin before riveting.

     Gear – шестерня, устройство, механизм, привод, шасси

1. The adjusting gear of this machine is in perfect order. 2. The friction gear plates should be safeguarded against lubricants. 3. The aircraft landed with its landing gear up. 4. The driven gear was not meshed with the intermediate one.

Key – ключ, телеграфный ключ, гаечный ключ, дверной ключ, шпонка, клавиша, код

1. Upon pressing this key down the machine starts working. 2. The radio operation transmitted our request by means of the key in no time. 3. This key does not fit into this key-hob. 4. The wheel was fixed on its shaft by means of a straight key.