CHAPTER 5 SPRINGS

Spring

What is a Spring?

A spring is a device or an elastic object or a coiled piece of steel /other materials. A coiled spring also known as a helical spring.A coiled spring changes shapes when applied external force on it and return to its original shapes when force removed. If too much force applied, the coiled spring will permanently deform and will never return to its original shape.

Will a Spring Changes in Size & Shape?

Yes. A spring will change it size and shape when we:

• bend it - when a spring is bent, the size and shape of the spring are changed and when let go, the spring returns to its original size and shape;
• twist it - when a spring is twisted, the size and shape of the spring are changed and when let go, it returns to its original size and shape;
• squeeze/compress it - when a spring is squeezed/compressed, it becomes shorter and when the spring is released, the spring will return to its original length;
• stretch it - when a spring is stretched, it becomes longer and after being released, it returns to original length.

 

What Affect the Stretching Ability of a Spring?

• The length or diameter or thickness of a spring affect its ability to stretch more (easy to stretch) or less (difficult to stretch).
• Length. A longer spring is easier to stretch than a shorter spring. In other words, the shorter the spring, the less it stretches.

Diameter. A bigger diameter spring is easier to stretch than a smaller diameter spring. In other words, the smaller the diameter of the spring, the less it stretches.

Thickness. A thinner spring is easier to stretch than a thicker spring. In other words, the thicker the spring, the less it stretches.

Different weights of an object that hung at the end of a same spring will give different answer to its stretching ability. The heavier the object hung, the longer the spring stretches.

Basic Types of Springs

There are 3 basic types of springs.

Extension / Tension Spring

The coils normally touch together and when force applied to stretch the spring, the coils will separate. Examples of objects with the uses of extension/tension springs:

Source: Pohl Spring Works

baby hammock - to provide gently bouncing when baby was placed into it

stapler - to push the staplers forward and to keep the staplers in place;

spring balance - to measure weigh or force

Compression Spring

There are space between successive coils and when force applied to shorten the spring, the coils will push closer together. Examples of objects with the uses of compression springs:

Source: Pohl Spring Works

ballpoints pens - to push the nib in and out

pogo sticks - to bounce in a standing position off the ground

umbrellas - to extend or open it

toasters - to spring out the toast automatically when time out

mechanical pencils - to push the lead out

torches (battery holder) - to allow and hold the inserted battery

rocking horse - to allow it to move up and down

Torsion Spring

When force were applied to twist the coil, the spiral coil will be tightened. Examples of objects with the uses of torsion springs:

Source: Pohl Spring Works

mousetrap - to store energy and subsequently release it with the attached bar to pin a mouse to the base

clothes peg - to hold clothes tightly on a clothesline

clipboard - to hold papers tightly on the board

Other Objects with the Uses of Springs

mattress - to make it comfortable to sleep or sit on

vehicle - for suspension to allow a smooth and balance ride

office chair - to allow it to change the height of the chair

trampoline - to provide the rebounding force, such as to allow acrobats jump high into the air