1. PREPARED BY R.A.ARUL RAJA ASSISTANT PROFESSOR SRM UNIVERSITY
BASIC MECHANICAL ENGINEERING
PREPARED BY
R.A.ARUL RAJA
ASSISTANT PROFESSOR
SRM UNIVERSITY

2. MACHINE ELEMENTS

3. SPRINGS
Spring is an elastic body which deflects to certain position when force is applied and it recovers its original shape when the force is released

4. TYPES OF SPRINGS Hellical spring Conical and volute springs
Torsion spring
Spiral spring
Leaf spring

5. HELLICAL SPRING TYPES Compression hellical spring (open coiled)
Tension hellical spring (closed coiled)

6. Compression helical spring (open coiled)

7. Tension hellical spring (closed coiled)

8. In open coiled hellical springs the spring wire is coiled in such a way that there is a large gap between two consecutive turns
In closed coiled hellical springs the spring wire is coiled so close such a way that there is no gap between two consecutive turns

9. TENSION HELICAL SPRING (OR) CLOSED COILED SPRING
It has some means of transferring the load from the support to the body by means of some arrangement.
It stretches apart to create load.
The gap between the successive coils is small.
The wire is coiled in a sequence that the turn is at right angles to the axis of the spring.
The spring is loaded along the axis.
By applying load the spring elongates in action

10. CONICAL AND VOLUTE SPRINGS
These springs are used in special applications.
Here the number of active coils gradually decreases

11. TORSION SPRINGS
If the load given is torsional load then the spring is called as torsion springs.

12. TORSION SPRING
It is also a form of helical spring, but it rotates about an axis to create load.
It releases the load in an arc around the axis.
Mainly used for torque transmission
The ends of the spring are attached to other application objects, so that if the object rotates around the center of the spring, it tends to push the spring to retrieve its normal position.

13. SPIRAL SPRING
It is made of a band of steel wrapped around itself a number of times to create a geometric shape.
Its inner end is attached to an arbor and outer end is attached to a retaining drum.
It has a few rotations and also contains a thicker band of steel.
It releases power when it unwinds.

14. LEAF SPRING

15. LEAF SPRING
It consists of number of flat plates of varying lengths held together by means of clamps and bolts. These springs are mostly used in automobiles.

16. SPRING MATERIALS
The mainly used material for manufacturing the springs are as follows:
Hard drawn high carbon steel )Chrome vanadium.
Oil tempered high carbon steel ) Chrome silicon.
Stainless steel
Copper or nickel based alloys.
Phosphor bronze.
Inconel.
Monel
Titanium.

17. Kequivalent-when springs are in series

18. Kequivalent-when springs are in parallel
(Δ1= Δ2)

19. COMBINED SYSTEM (BOTH SERIES AND PARALLEL)

20. APPLICATIONS OF SPRINGS
To apply forces and controlling motion, as in brakes and clutches.
Measuring forces, as in the case of a spring balance.
Storing energy, as in the case of springs used in watches and toys.
Reducing the effect of shocks and vibrations in vehicles and machine foundations.

21. SPRING NOMENCLATURE

22. Solid length= nxd
n= total no. of coils
d= diameter of wire
Free length= Solid length + max. compression+ clearance (max 1 mm)

23. SPRING INDEX: D/d
D=mean diameter of the coil
d=diameter of wire
SPRING RATE (stiffness): K=F/δ
F= Load applied
δ= deflection of spring
Pitch= Distance between two adjacent coils in
uncompressed state

24. THANK YOU