7.
What is spring index (C)?
The ratio of mean or pitch diameter to the diameter of wire for the spring is called the spring
index.
8.
What is pitch?
The axial distance between adjacent coils in uncompressed state.
9.
What is solid length?
The length of a spring under the maximum compression is called its solid length.
It is the
product of total number of coils and the diameter of wire.
Ls = nt x d
Where, nt = total number of coils.
10.
What are the requirements of spring while designing?
a.
Spring must
carry
the
service
load
without
the
stress
exceeding
the safe value.
b. The spring rate must be satisfactory for the given application.
11 What are the end conditions of spring?
(a) Plain end. (b) Plain and ground end (c). Squared end (d) Squared and ground end.
12.
What is buckling of springs?
The
helical
compression
spring
behaves
like
a
column
and
buckles
at
a comparative
small
load when
the
length
of
the
spring
is more
than
4
times
the mean coil diameter.
13.
What is surge in springs?
The material is subjected to higher stresses, which may cause early fatigue failure.
This effect is
called as spring surge.
14.
What is a laminated leaf spring?
In order to increase, the load carrying capacity, number of flat plates are placed and below the
other.

S.K.P. Engineering College, Tiruvannamalai
V SEM
90
Mechanical Engineering Department
Design of machine elements
15.
What semi
–
elliptical leaf springs?
The
spring
consists
of
number
of
leaves, which
are
held
together
by U-clips.
The long
leaf fastened to the supported is called master leaf.
Remaining leaves are called as graduated
leaves.
16.
What is nipping of laminated leaf spring?
Prestressing of leaf springs is obtained by a difference of radii of curvature known as nipping.
17.
What are the various applications of springs?
The springs are used in various applications, they are
a. Used to absorb energy or shocks (e.g. shock absorbers, buffers, e.t.c.)
b. To apply forces as in brakes clutches, spring-loaded valves, e.t.c.
c. To measure forces as in spring balances and engine indicators
d. To store energy as in watches
18.
Define free length.
Free length of the spring is the length of the spring when it is free or unloaded condition.
It
is
equal
to
the
solid
length
plus
the
maximum
deflection
or compression plus clash allowance.
Lf = solid length + Ymax + 0.15 Ymax
19.
Define spring index. (ODD- 2011)
Spring index (C) is defined as the ratio of the mean diameter of the coil to the diameter of the
wire.
C =D/d
20.
Define spring rate (stiffness). (ODD- 2011)(EVEN-2016)
The spring stiffness or spring constant is defined as the load required per unit deflection of the
spring.
K= W/y
Where
W-load
Y-deflection