4th post- Machines & Mechanisms

Machines & Mechanisms

 1-When a structure is stable ?

 We say that a structure is stable when it remainds in equilibrium even when a force is applied to it  

 2-When is the centre of gravity ?

  The centre of gravity is the point where the weight of an object is considered to be concentrated.

3-What is a machine ?

 We use the word machine to describe a set of elements or parts thet work together and use energy to perform a task and obtain a result.It has three components:

1-Driver element: feeds energy to the machine 

2-Driven element : recieves the force produced in the machine

3-Converting and/or trasmitting element-: trasmits and / or converts the motion from the driver element to the driven element,

4-What is mechanism ?

 Devices that transmit an/or convert motion.

Motion transmission mechanisms:the mechanism is feed enrgy from the driver element and simply transfers it to the driven elements.

We can class motion transmissions machines as:

• Linear transmission mechanisms. there are type ofsimple machine.
• Rotary transmission mechanisms. these include friction wheels ,belt and pulley systems ,gears, chain and sprocket systems,and woems gears.

  Motion conversion mechanisms. The mechanism converts the mpvement from the driver element into a movement that the driven element can use.Example:nuts and bolts.                                           

5-What is a lever ?

A lever is a rigid bar that can pivot on point of support called a fulcrum.

5-What is a pulley?

Is used to lift heavy loads.they are wheels with a grooved rim

6-Belt and pulley system

This system is made up of 2 pulley wheels joined by a belt that slots into the grooved rim of wheels.

7-Gear

A gear is mechanism consisting of two wheels with teeth.Example : correction tape