A variable geometry crane that can be used to practically demonstrate mechanical advantage to children.

Video of the crane in action can be found here,

This crane should only be used under adult supervision to prevent potential injury.

Two interchangeable winch handles are provided to let people feel the difference cause by having different diameters and hence different turning moments.

The gantry pin over which the string passes can be changed to three different heights or left out to demonstrate the effect of the geometry of the crane on the mechanical advantage.

The crane needs to be screwed down to a piece of wood. It has been tested up to a maximum of 1k.g. load. Use only string that can support at least 1k.g. 

The hook should be printed on it's side to prevent print "grain" effects weakening it.

To prevent the winch unwinding a ratchet mechanism is added. This also gives a working demonstration of a mechanism. This should only be used under adult supervision to prevent potential injury to fingers.

During construction it will be necessary to hammer the Gantry & Pivot into place in the Platform. When doing this protect the 3d printed components with pieces of wood and hit the wood.

Proof test before using.

NO responsibility is accepted for any loss or injury caused by this design. Use commonsense to prevent unfortunate incidents. Never place any part of your body under an unsupported load.