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AUTOMATIC SPRING ROLLING MACHINE

SYNOPSIS

In spring working industry a wide range of power and hand

operated machines are used. As the industry is a large and growing

industry different type of machines are used for different operations.

Our project the spring rolling machine is very simple in operation by

using spur gear arrangement which is coupled with motor. This

machine produces round spring of different diameters and length. This

machine can be used in various fields. This machine consist of two spur

gear which is coupled with a motor and connecting the spur gear shaft

with rolling main shaft. This machine is simple in construction and

working principle.

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INTRODUCTION

Spring rolling industry is a large and growing industry. There are

many special purposes machines used in this industry to-day. The

proper selection of the machines depends upon the type of the work

under-taken by the particular industry. There are many examples of

spring, which can be seen in our every day lives. The metals generally

used for spring rolling work include iron, copper, tin, aluminium,

stainless and brass.

Our project the “SPRING ROLLING MACHINE” finds huge

application in all spring rolling industry. Rolling is the process of

bending metal wire to a curved form. The article in the shape of round

is made by spring roller shaft. Rolling operation can be done on hand

or power operated rolling machines. In forming round spring shapes a

gradual curve is to be put in the metal rather than sharp bends. The

gap between the springs can be regulated by proper arrangement.

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The lock nut is used to fixing the spring wire to the rolling shaft.

The spring wire is supplied by a tare is called spring wire tare. This tare

is fixed to the stand by two end bearings. The tare is rotated freely

during the time of spring rolling operation. The single phase induction

motor is coupled with the spur gear arrangement by pulleys. The motor

is rotated by switch on the power supply of single phase. The spur gear

is rotated due to the rotation of motor. The spur gear is coupled with

the main shaft by bearing.

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WORKING PRINCIPLE

The single phase supply is given to the induction motor, it will

run. The motor pulley is coupled to the spur gear pulley with the help

of belt. The spur gear arrangement is run according to the speed of the

motor. Before switch on the induction motor, the spring wire is locked

to the lock nut in the spring rolling shaft. The spring wire is supply by a

spring wire tare. The tare is fixed to the frame stand by two end

bearings, so that it will run freely according to the speed of the spring

rolling shaft.

The spring rolling shaft is rotated when the single phase induction

motor switched ON. The spring wire is rolling in the rolling shaft due to

the rotation of the spring rolling shaft. The length of the rolling spring

is decided by the operator. The required length of the spring is rolled;

the single phase induction motor is switched OFF. The spring is cut by

the cutter, the next above procedure continue once again for the next

spring operation.

ADVANTAGES

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Easy in Construction and Working Principle

Man power requirement is less

High production

Length of the spring is varied

Production cost is reduced

Low Cost

Maintenance cost is very low.

Unit is compact so less space is required

Time consumption is less

Less effort & productive

Easy to install at any were

Skilled workers are not required

Convenient for mass production

Less in weight

APPLICATIONS

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Small Scale industries such as wire rolling, belt rolling

etc.

Wire rolling industries

All spring rolling industries

DISADVANTAGES

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This machine is applicable for particular diameter of

the spring

This machine is used to produce soft spring wire only

The Purpose

Coil springs are a spiral thick metal wire that is made of steel. Used in a car’s

suspension system to hold the weight, keep the ride height and control the

ride of the vehicle.

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Why replace coil springs?

There are many factors as to why coil springs are replaced. Some are by

choice and other because they need replacing. Below are some of the

reasons coil springs are replaced.

Sagging

Coil springs support a car’s body; over time coil springs will weaken and sag

causing the ride height to lower. As the coil springs sag, on side of the car

may be lower than the other and case the car to tilt.

Tyre wear

While stabilising the car’s body, coil springs and shocks keep a car’s tyres

firmly on the ground, keeping the axles at the correct angles. Warn coil

springs and shocks can misalign tyres and/or track abnormally, causing early

tyre wear.

Noise

When a car is driven over large bumps, pot holes and/or around tight corners

if a noise occurs, this often is a sign of worn coil springs and/or shock

absorbers.

Bounce

When driving if you car is bouncing or feels like you’re in a boat, you need to

replace your coil springs and/or shock absorbers.

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Swaying

Coil springs and shocks work together to keep a car centered and stabilized

while going around tight corner. Worn coil springs and shock absorbers loose

their stabilising capabilities and cause a car to sway excessively.

Height

By replacing the coil springs you can choose the ride height. There is

typically three options for most cars these being:

*             Standard height

Restore the car to its formal ride height

*             Lowered height

There are options of 20mm to 60mm lower than original height. When

lowering a car remembers the car will be closer to the road, tyres and

suspension bump stops. Depending on how lowered you choose, you may

also need to replace your shock absorbers.

*             Raised height

Options are 20mm to 50mm raised above original height of the car. Why

raise the ride height?

For many reasons for example towing, LPG tank, 4WDing, load carrying and

for increased ground clearance.

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A

SPRING is an elastic

object used to store mechanical energy. Springs are usually made out of

spring steel. Small springs can be wound from pre-hardened stock, while

larger ones are made from annealed steel and hardened after fabrication.

Some non-ferrous metals are also used including phosphor bronze and

titanium for parts requiring corrosion resistance and beryllium copper for

springs carrying electrical current (because of its low electrical resistance).

When a spring is compressed or stretched, the force it exerts is proportional

to its change in length. The rate or spring constant of a spring is the change

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in the force it exerts, divided by the change in deflection of the spring. That

is, it is the gradient of the force versus deflection curve. An extension or

compression spring has units of force divided by distance, for example lbf/in

or N/m. Torsion springs have units of force multiplied by distance divided by

angle, such as N·m/rad or ft·lbf/degree. The inverse of spring rate is

compliance, that is: if a spring has a rate of 10 N/mm, it has a compliance of

0.1 mm/N. The stiffness (or rate) of springs in parallel is additive, as is the

compliance of springs in series.

Depending on the design and required operating environment, any material

can be used to construct a spring, so long as the material has the required

combination of rigidity and elasticity: technically, a wooden bow is a form of

spring.

Springs can be classified depending on how the load force is applied to them:

Tension/Extension spring – the spring is designed to operate with a

tension load, so the spring stretches as the load is applied to it.

Compression spring – is designed to operate with a compression load,

so the spring gets shorter as the load is applied to it.

Torsion spring – unlike the above types in which the load is an axial

force, the load applied to a torsion spring is a torque or twisting force,

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and the end of the spring rotates through an angle as the load is

applied.

Constant spring - supported load will remain the same throughout

deflection cycle[5]

Variable spring - resistance of the coil to load varies during

compression[6]

They can also be classified based on their shape:

Coil spring – this type is made of a coil or helix of wire

Flat spring – this type is made of a flat or conical shaped piece of

metal.

Machined spring - this type of spring is manufactured by machining bar

stock with a lathe and/or milling operation rather than coiling wire.

Since it is machined, the spring may incorporate features in addition to

the elastic element. Machined springs can be made in the typical load

cases of compression/extension, torsion, etc.

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The most common TYPES OF SPRING are:

Cantilever spring – a spring which is fixed only at one end.

Coil spring or helical spring – a spring (made by winding a wire around

a cylinder) and the conical spring – these are types of torsion spring,

because the wire itself is twisted when the spring is compressed or

stretched. These are in turn of two types:

o Compression springs are designed to become shorter when

loaded. Their turns (loops) are not touching in the unloaded

position, and they need no attachment points.

A volute spring is a compression spring in the form of a

cone, designed so that under compression the coils are not

forced against each other, thus permitting longer travel.

o Tension or extension springs are designed to become longer

under load. Their turns (loops) are normally touching in the

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unloaded position, and they have a hook, eye or some other

means of attachment at each end.

Hairspring or balance spring – a delicate spiral torsion spring used in

watches, galvanometers, and places where electricity must be carried

to partially rotating devices such as steering wheels without hindering

the rotation.

Leaf spring – a flat spring used in vehicle suspensions, electrical

switches, and bows.

V-spring – used in antique firearm mechanisms such as the wheellock,

flintlock and percussion cap locks.

Other types include:

Belleville washer or Belleville spring – a disc shaped spring commonly

used to apply tension to a bolt (and also in the initiation mechanism of

pressure-activated landmines).

Constant-force spring — a tightly rolled ribbon that exerts a nearly

constant force as it is unrolled.

Gas spring – a volume of gas which is compressed.

Ideal Spring – the notional spring used in physics: it has no weight,

mass, or damping losses.

Mainspring – a spiral ribbon shaped spring used as a power source in

watches, clocks, music boxes, windup toys, and mechanically powered

flashlights

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Negator spring – a thin metal band slightly concave in cross-section.

When coiled it adopts a flat cross-section but when unrolled it returns

to its former curve, thus producing a constant force throughout the

displacement and negating any tendency to re-wind. The commonest

application is the retracting steel tape rule.[7]

Progressive rate coil springs – A coil spring with a variable rate, usually

achieved by having unequal pitch so that as the spring is compressed

one or more coils rests against its neighbour.

Rubber band – a tension spring where energy is stored by stretching

the material.

Spring washer – used to apply a constant tensile force along the axis of

a fastener.

Torsion spring – any spring designed to be twisted rather than

compressed or extended. Used in torsion bar vehicle suspension

systems.

Wave spring – a thin spring-washer into which waves have been

pressed.[8]

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Contents

 [hide] 

1 History

2 Types

3 Physics

o 3.1 Hooke's law

o 3.2 Simple harmonic motion

4 Theory

5 Zero-length springs

6 Uses

7 References

8 Further reading

9 External links

[edit] History

Simple non-coiled springs were used throughout human history e.g., the bow

(and arrow). In the Bronze Age more sophisticated spring devices were used,

as shown by the spread of tweezers in many cultures. Ctesibius of Alexandria

developed a method for making bronze with spring-like characteristics by

producing an alloy of bronze with an increased proportion of tin, and then

hardening it by hammering after it is cast.

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Coiled springs appeared early in the 15th century,[1] in door locks.[2] The first

spring powered-clocks appeared in that century[2][3][4] and evolved into the

first large watches by the 16th century.

In 1676 British physicist Robert Hooke discovered the principle behind

springs' action, that the force it exerts is proportional to its extension, now

called Hooke's law.

[edit] Types

A spiral torsion spring, or hairspring, in an alarm clock.

A volute spring. Under compression the coils slide over each other, so

affording longer travel.

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Vertical volute springs of Stuart tank

Tension springs in a folded line reverberation device.

A torsion bar twisted under load

Leaf spring on a truck

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Springs can be classified depending on how the load force is applied to them:

Tension/Extension spring – the spring is designed to operate with a

tension load, so the spring stretches as the load is applied to it.

Compression spring – is designed to operate with a compression load,

so the spring gets shorter as the load is applied to it.

Torsion spring – unlike the above types in which the load is an axial

force, the load applied to a torsion spring is a torque or twisting force,

and the end of the spring rotates through an angle as the load is

applied.

Constant spring - supported load will remain the same throughout

deflection cycle[5]

Variable spring - resistance of the coil to load varies during

compression[6]

They can also be classified based on their shape:

Coil spring – this type is made of a coil or helix of wire

Flat spring – this type is made of a flat or conical shaped piece of

metal.

Machined spring - this type of spring is manufactured by machining bar

stock with a lathe and/or milling operation rather than coiling wire.

Since it is machined, the spring may incorporate features in addition to

the elastic element. Machined springs can be made in the typical load

cases of compression/extension, torsion, etc.

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The most common types of spring are:

Cantilever spring – a spring which is fixed only at one end.

Coil spring or helical spring – a spring (made by winding a wire around

a cylinder) and the conical spring – these are types of torsion spring,

because the wire itself is twisted when the spring is compressed or

stretched. These are in turn of two types:

o Compression springs are designed to become shorter when

loaded. Their turns (loops) are not touching in the unloaded

position, and they need no attachment points.

A volute spring is a compression spring in the form of a

cone, designed so that under compression the coils are not

forced against each other, thus permitting longer travel.

o Tension or extension springs are designed to become longer

under load. Their turns (loops) are normally touching in the

unloaded position, and they have a hook, eye or some other

means of attachment at each end.

Hairspring or balance spring – a delicate spiral torsion spring used in

watches, galvanometers, and places where electricity must be carried

to partially rotating devices such as steering wheels without hindering

the rotation.

Leaf spring – a flat spring used in vehicle suspensions, electrical

switches, and bows.

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V-spring – used in antique firearm mechanisms such as the wheellock,

flintlock and percussion cap locks.

Other types include:

Belleville washer or Belleville spring – a disc shaped spring commonly

used to apply tension to a bolt (and also in the initiation mechanism of

pressure-activated landmines).

Constant-force spring — a tightly rolled ribbon that exerts a nearly

constant force as it is unrolled.

Gas spring – a volume of gas which is compressed.

Ideal Spring – the notional spring used in physics: it has no weight,

mass, or damping losses.

Mainspring – a spiral ribbon shaped spring used as a power source in

watches, clocks, music boxes, windup toys, and mechanically powered

flashlights

Negator spring – a thin metal band slightly concave in cross-section.

When coiled it adopts a flat cross-section but when unrolled it returns

to its former curve, thus producing a constant force throughout the

displacement and negating any tendency to re-wind. The commonest

application is the retracting steel tape rule.[7]

Progressive rate coil springs – A coil spring with a variable rate, usually

achieved by having unequal pitch so that as the spring is compressed

one or more coils rests against its neighbour.

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Rubber band – a tension spring where energy is stored by stretching

the material.

Spring washer – used to apply a constant tensile force along the axis of

a fastener.

Torsion spring – any spring designed to be twisted rather than

compressed or extended. Used in torsion bar vehicle suspension

systems.

Wave spring – a thin spring-washer into which waves have been

pressed.[8]

[edit] Physics

[edit] Hooke's law

Main article: Hooke's law

As long as they are not stretched or compressed beyond their elastic limit,

most springs obey Hooke's law, which states that the force with which the

spring pushes back is linearly proportional to the distance from its

equilibrium length:

where

x is the displacement vector – the distance and direction the spring is

deformed from its equilibrium length.

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F is the resulting force vector – the magnitude and direction of the

restoring force the spring exerts

k is the rate, spring constant or force constant of the spring, a

constant that depends on the spring's material and construction.

Coil springs and other common springs typically obey Hooke's law. There are

useful springs that don't: springs based on beam bending can for example

produce forces that vary nonlinearly with displacement.

[edit] Simple harmonic motion

Main article: Harmonic oscillator

Since force is equal to mass, m, times acceleration, a, the force equation for

a spring obeying Hooke's law looks like:

The displacement, x, as a function of time. The amount of time that passes

between peaks is called the period.

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The mass of the spring is assumed small in comparison to the mass of the

attached mass and is ignored. Since acceleration is simply the second

derivative of x with respect to time,

This is a second order linear differential equation for the displacement as a

function of time. Rearranging:

the solution of which is the sum of a sine and cosine:

and are arbitrary constants that may be found by considering the initial

displacement and velocity of the mass. The graph of this function with

(zero initial position with some positive initial velocity) is displayed in the

image on the right.

[edit] Theory

In classical physics, a spring can be seen as a device that stores potential

energy, specifically elastic potential energy, by straining the bonds between

the atoms of an elastic material.

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Hooke's law of elasticity states that the extension of an elastic rod (its

distended length minus its relaxed length) is linearly proportional to its

tension, the force used to stretch it. Similarly, the contraction (negative

extension) is proportional to the compression (negative tension).

This law actually holds only approximately, and only when the deformation

(extension or contraction) is small compared to the rod's overall length. For

deformations beyond the elastic limit, atomic bonds get broken or

rearranged, and a spring may snap, buckle, or permanently deform. Many

materials have no clearly defined elastic limit, and Hooke's law can not be

meaningfully applied to these materials. Moreover, for the superelastic

materials, the linear relationship between force and displacement is

appropriate only in the low-strain region.

Hooke's law is a mathematical consequence of the fact that the potential

energy of the rod is a minimum when it has its relaxed length. Any smooth

function of one variable approximates a quadratic function when examined

near enough to its minimum point as a result of the Taylor series. Therefore,

the force—which is the derivative of energy with respect to displacement—

will approximate a linear function.

Force of fully compressed spring

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where

E – Young's modulus

d – spring wire diameter

L – free length of spring

n – number of active windings

– Poisson ratio

D – spring outer diameter

[edit] Zero-length springs

"Zero-length spring" is a term for a specially designed coil spring that would

exert zero force if it had zero length. That is, in a line graph of the spring's

force versus its length, the line passes through the origin. Obviously a coil

spring cannot contract to zero length because at some point the coils will

touch each other and the spring will not be able to shorten any more. Zero

length springs are made by manufacturing a coil spring with built-in tension,

so if it could contract further, the equilibrium point of the spring, the point at

which its restoring force is zero, occurs at a length of zero. In practice, zero

length springs are made by combining a "negative length" spring, made with

even more tension so its equilibrium point would be at a "negative" length,

with a piece of inelastic material of the proper length so the zero force point

would occur at zero length.

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A zero length spring can be attached to a mass on a hinged boom in such a

way that the force on the mass is almost exactly balanced by the vertical

component of the force from the spring, whatever the position of the boom.

This creates a horizontal "pendulum" with very long oscillation period. Long-

period pendulums enable seismometers to sense the slowest waves from

earthquakes. The LaCoste suspension with zero-length springs is also used in

gravimeters because it is very sensitive to changes in gravity. Springs for

closing doors are often made to have roughly zero length so that they will

exert force even when the door is almost closed, so it will close firmly.

Hooke's Law

Springs are fundamental mechanical components which form the basis of

many mechanical systems. A spring can be defined to be an elastic member

which exerts a resisting force when its shape is changed. Most springs are

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assumed linear and obey the Hooke's Law,

where F is the resisting force, D is the displacement, and the k is the spring

constant.

For a non-linear spring, the resisting force is not linearly proportional to its

displacement. Non-linear springs are not covered in depth here.

Basic Spring Types

Springs are of several types, the most plentiful of which are shown as

follows,

Circular cross section springs are shown. If space is limited, such as with

automotive valve springs, square cross section springs can be considered. If

space is extremely limited and the load is high, Belleville washer springs can

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be considered. These springs are illustrated below,

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Leaf springs, which are illustrated below in a typical wheeled-vehicle

application, can be designed to have progressive spring rates. This "non-

linear spring constant" is useful for vehicles which must operate with widely

varying loads, such as trucks.

History of Springs

Like most other fundamental mechanisms, metal springs have existed since

the Bronze Age. Even before metals, wood was used as a flexible structural

member in archery bows and military catapults. Precision springs first

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became a necessity during the Renaissance with the advent of accurate

timepieces. The fourteenth century saw the development of precise clocks

which revolutionized celestial navigation. World exploration and conquest by

the European colonial powers continued to provide an impetus to the

clockmakers' science and art. Firearms were another area that pushed spring

development.

The eighteenth century dawn of the industrial revolution raised the need for

large, accurate, and inexpensive springs. Whereas clockmakers' springs were

often hand-made, now springs needed to be mass-produced from music wire

and the like. Manufacturing methodologies were developed so that today

springs are ubiquitous. Computer-controlled wire and sheet metal bending

machines now allow custom springs to be tooled within weeks, although the

throughput is not as high as that for dedicated machinery.

Risk Factors

Compression spring bucking refers to when the spring deforms in a non-axial

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direction, as shown here,

Buckling is a very dangerous condition as the spring can no longer provide

the intended force. Once buckling starts, the off-axis deformation typically

continues rapidly until the spring fails. As a result, it is important to design

compression springs such that their likeliness to buckle is minimized.

Buckling of compression springs is similar to buckling for vertical structural

columns. When the free height of the spring (Lfree) is more than 4~5 times

the nominal coil diameter D, the spring can buckle under a sufficiently heavy

load.

The maximum allowable spring deflection Dmax that avoids buckling depends

on the free length, the coil diameter, and the spring ends (pivot ball, ground

& squared, etc.).

Buckling Thresholds

One quick method for checking for buckling is to compute the deflection to

free height ratio (D/Lfree) and use the following chart to check if the ratio

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exceeds the maximum allowable value:

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