Toys Using Levers

Along with cams and cranks, many mechanical toys use levers to transmit energy from one side of the toy to the other. There are three classes of levers. The most used and the most useful are the First Class levers. By moving the pivot they allow you to transmit power in different ways as shown below:

Figure A

Figure B

Figure C

• The lever on Figure A transmits equal power on both sides. This means that to lift a load on one side you need to use the same power you would use to lift the load directly, without level. The difference however is that when using a lever the direction is the opposite (to move the load up you need to press the lever down).
• The lever on Figure B uses less power to lift the load than you would use otherwise. But of course you have to move the right side of the lever a lot more than the load is lifted. This is a typical lever used in real world engineering.
• The lever on Figure C requires more power to lift the load. However it lifts the load a lot more than you move the lever. This type of levers is often used in mechanical toys.

This whole ting is explained in even more details here.

Usually levers work together with cams and cranks to transmit the power along the line. The links below will give you some ideas about how toys use levers:

• A lever toy project using class one lever. This is a project for kids between 7 and 9 years. It shows the typical small movement - large output lever usage that was explained in figure C above.
• How To Make A Simple Toy With Lever Wedge And Screw - short guide, unfortunately no pictures. But it's still a good start.
• For a nice example of a wooden lever toy, check this page.

Building lever toys is great for children education so consider including such activities in your home school or local school education program.