JSS 2: Simple machine (I)

A machine is a device used to overcome load at one end by the application of effort at the other end. It is used to transfer energy from one place to another. A machine that has no friction is called an ideal (perfect) machine. Examples of machines are, pliers, wheelbarrows, screwjack, etc 

                  Types of machine 

The different types of machines are:

1. Lever 

2. Pulleys 

3. Inclined plane 

4. Screw 

5. Wheel and axle 

6. Wedge 

7. Gear wheels 

8. Hydraulic press 

                              Lever 

A lever is a simple machine consisting of a rigid rod pivoted at a fulcrum.

Terms used about lever:

1. Effort: Effort is the force applied 

2. Load: Load is the object been lifted 

3. Fulcrum: The fulcrum is the point of pivoting.

                         Types of lever 

There are three classes of levers:

1. First-order lever 

2. Second-order lever 

3. Third-order lever 

                         First-order lever 

In first-order lever, the fulcrum is between the load and the effort.

Example: Scissors, pliers, crowbar, claw hammer etc 

                 Second-order lever 

In the second-order lever, the load is between the fulcrum and the effort.

Example: Wheelbarrow, nutcracker, nail clipper, bottle opener, etc 

                   Third-order lever 

In the third-order lever, the effort is between the fulcrum and the load.

Example: Tongs, forearm, forceps, stapler, etc 

            Maintenance of machines 

Ways of taking care of a machine include the following:

1. Ensure regular lubrication 

2. Clean the machine thoroughly after use 

3. Check the machine for wear and tear 

4. Keep the machine in a dry place after use 

5. Avoid exceeding performance specification