Clutches
A clutch is a device for connecting two parts, such as a shaft and a pulley. The difference between a coupling and a clutch is that a coupling and a clutch is that a coupling is used to connect two shafts permanently, while a clutch may ensure easy and quick connection and disconnection of two shafts. Clutches used in lather, are subdivided into several types, such as rigid coupling and disengaging clutches. A rigid coupling serves for connecting coaxial shafts which are not disengaged in the process of operation. A rigid coupling consists of a solid bushing connecting electric motor and lathe shaft by means of a key.
Disengaging clutches are applied in lathes for temporary engagement and disengagement of a shaft and parts connected to it. They are divided into friction clutches and jaw clutches . Friction clutches serve to connect a stationary machine part to transmit the required power. Sometimes friction clutches are intended as safety devices to prevent breakage of parts in the transmission train. Friction clutches may be divided into two groups according to the direction of acting force: axial clutches and radial or rim clutches Axial clutches can be subdivided into cone clutches, and combined cone and disc clutches. By turning the eccentric clamp to 90 the friction clutch is disengaged , a spring pressing out the toothed wheel from the friction disc. Radial or rim clutches may be classified as band clutches, block clutches, and as external, internal, and combined internal and external clutches. Jaw clutches consist of two half-clutches - a fixed one and a movable one which have jaws on their faces. The fixed half-clutch is rigidly fastened on one shaft, the movable one being keyed to another shaft. The shafts are connected through the coupling of jaws on both, half-clutches.
ІІІ. Language.
Ex.9. Match words and word combinations in column A with those in column B:
Column A |
Column B |
|
|
Ex.10. Match words and their definitions:
|
|
Ex.11. Find the right ending of the sentences and translate these sentences:
A clutch is a device ……………. .
which may be divided into two groups.
for connecting coaxial shafts.
connecting two shafts or a shaft and a pulley.
A coupling is used ………………. .
to connect two shafts permanently.
to connect a stationary machine part.
to ensure easy and quick connection and disconnection of two shafts.
Disengaging clutches are applied ………….. .
as safety devices to prevent the breakage of parts.
in lathes for temporary engagement and disengagement of a shaft and parts connected with it.
for connecting coaxial shafts which are not disengaged in the process of operation.
Friction clutches serve ……………… .
to connect two shafts permanently.
to connect electric motor and lathe shaft by means of a key .
as safety devices to prevent the breakage of parts in the transmission train.
Friction clutches may be divided into : ………………. .
two groups, according to the direction of the acting force: axial clutches and rim clutches.
cone clutches and combined cone and disk clutches.
band clutches and block clutches.
Disengaging clutches are divided into: …………….. .
axial and radial clutches.
friction clutches and jaw clutches.
band and block clutches.
Ex. 12 Fill in the blanks using the following words:
fixed clutch, b) disengaged, c) ensure, d) block clutch, e) to protect, f) rim clutch.
Jaw clutches consist of two half-clutches: ……….. and a movable one which have jaw on their faces.
Radial or rim clutches may be classified as band clutches, …………… and as external clutches.
Friction clutches may be divided into two groups: axial clutches and …………… .
A clutch may …………… easy and quick connection and disconnection of two shafts.
A rigid coupling serve for connecting coaxial shafts which are not ………… in the process of operation.
Sometimes friction clutches are intended as safety devices to ………….. the breakage of parts in the transmission train.
Ex. 12 Answer the questions:
What is the difference between a clutch and a coupling?
How are clutches subdivided?
What does a rigid coupling serve for?
What is a disengaging clutch applied for?
What is a friction clutch?
How are friction clutches classified?
What is the difference in application of the contact pressure in axial clutches and in radial clutches?
Ex. 13. Give information about clutches using the table .
Clutches a
device to
connect two parts
Rigid coupling to
connect coaxial
shafts
Disengaging clutches temporary
engagement disengagement
of a shaft
Friction clutches to
transmit the
required power to
connect a
stationary machine parts
Jaw clutches devices
to prevent breakage
of parts
Axial clutches direction
of acting force
Radial or rim clutches direction
of acting force
Half
clutch (fixed) to
connect through the coupling of jaws
Half
clutch (movable) to
connect through the coupling of jaws
Cone clutches
Combined
Cone &Disc clutches