nice ppt

1. Topic : TYPES OF PULLEY
Created by Rajesh Goswami

2.  Pulley
 Pulleys are used to transmit power from one shaft to another
with the help of belt or rope running over them.
 Pulleys are made from cast iron,cast steel, wrought iron or
aluminium.

3.  The main part of pulley
Rim
Hub or boss
Arms or rib

4.  Rim
 It is the periphery of the pulley on which the belt runs.
 The outer face of the rim is made slightly convex which
is called crowning.
 This keep belts at centre when pulley is misaligned.

5.  Hub or boss
 It is the central hollow cylindrical portion of pulley as
shown in figure.
 The size of bore on hub is corresponds to the diameter
of the shaft.
 It is mounted on shaft.
 A keyway is provided to fasten the pulley to the shaft
with the help of a key.

6.  Arms or rib
 It is joining member of the hub and the rib of pulley.
 It may be straight or curved.
 It’s cross section may be circular or elliptical.
 Pulleys with smaller diameter are provided with a rib
which is like a circular disc joining hub and rim.

7.  Types of pulley
 Solid pulley
 Split pulley
 Stepped or cone pulley
 Fast and loose pulley
 Jockey pulley
 Guide pulley
 Grooved pulley

8.  Solid pulley
 It is made from single piece of cast iron .
 Solid pulley relatively smaller in size.
 This pulley can be mounted on shaft by inserting from
one end.

9.  Solid pulley

10. Split pulley
 It is split in two halves ,and it can be joined at the rim
and the hub by means of bolts or links.
 This pulley can be mounted on the shaft at any place
without changing the assembly of bearing and shaft.

11.  Split pulley

12.  Stepped or cone pulley
 Stepped pulley is used when the speed of the
driven shaft is to be changed very frequently as in
case of machine tools such as lathe , drilling
machine etc. a stepped pulley is an integral casting
having three or more number of pulleys of different
diameter as show in figure.
 Each stepped pulley is mounted on driving and driven
shaft can be varied by shifting the diameters of driving
and driven pulleys are such that same belt will operate
when shifted on different pairs of pulley.

13.  Stepped or cone pulley

14.  Fast and loose pulley
 When a number of machines run from a main driving shaft , it may require to start or
stop some of the machines intermittently without start or stop the main driving shaft
every time.
 This is possible by mounting pair of pulleys is securely keyed to the machine shaft so
that it can rotate along with shaft while the loose pulley fitted with brass bush so that it
can freely rotate on the shaft as shown in figure .
 The wider driving pulley keyed to the main driving shaft , hence it rotates along with it.
 When the belt on the fast pulley , the power is transmitted from driving shaft to the
machine shaft.
 When belt shifted from fast pulley to loose pulley , the loose pulley rotates through belt,
but machine shaft not rotates along with it because loose pulley can freely rotates on
shaft .
 The movement of belt from fast to loose pulley or loose to fast pulley take place by axial
movement of belt shifter.

15.  Fast and loose pulley

16. Jockey pulley
 Jokey pulley is idler pulley and is used to increase the
angle of contact in open belt drive.
 It is mounted near the smaller pulley of the two pulleys
and is placed on the slack side of the belt as shown in
figure.
 It increases angle of contact lead to increased power
transmission capacity of drive.

17.  Jockey pulley

18.  Guide pulley
 The guide pulleys are used to guide the belts when
connecting non-parallel, intersecting or non-
intersecting shafts.
 The guide pulleys guide the belt to keep the belt in a
proper plane as shown in figure.

19.  Guide pulley

20.  Grooved pulley
 Grooved pulley have V-grooves or circular grooves on
the rim to carry V-Belt or ropes.
 It is generally made from cast iron.
 The grooves on the rim is help to increase the frictional
grip of the belt or rope on the pulley.
 Therefore the chance of slip is reduced.
 Figure shows grooved pulley for V-belt and figure shows
grooved pulley for rope drive.

21.  Grooved pulley

22. Thank you…