Puzzle Basics

Unlike word or jigsaw puzzles, mechanical puzzles are hand-held objects that must be manipulated to achieve a specific goal. Mechanical puzzles are presented as a set of physically interlinked pieces. There are several categories of mechanical puzzles:

Assembly / Put-Together Puzzles

In this category the puzzle is present in component form, and the aim is to produce a certain shape. The Half Hour Puzzle and is an example of this type of puzzle. Assembly puzzles do not interlock, and are frequently presented as a packing puzzle where the goal is to fit the set of pieces into a container.

Disassembly / Take-Apart Puzzles

Puzzles in this category are usually solved by opening or dividing them into pieces. Some interlocking puzzles can be considered disassembly puzzles if the intended challenge is to take them apart.

Boxes called secret boxes or puzzle boxes with secret opening mechanisms are included in this category. These containers are locked by opening mechanisms which reveal a hollow space on opening. There are a vast variety of opening mechanisms, such as concealed panels, inclination mechanisms, magnetic locks, movable pins which need to be rotated into a certain position, etc.

Interlocking / Burr Puzzles

In an interlocking puzzle, one or more pieces hold the rest together, or the pieces are mutually self-sustaining. The aim is to completely disassemble and then reassemble the puzzle. Burr #306 is a classic example of an interlocking puzzle.  Both assembly and disassembly can be difficult – contrary to assembly puzzles, these puzzles usually do not just fall apart easily. The level of difficulty is usually assessed in terms of the number of moves required to remove the first piece from the initial puzzle.

Lock Puzzles

These puzzles, also called trick locks, are locks (often padlocks) which have an unusual locking mechanism. The aim is to open the lock. If you are given a key, it will not open the lock in the conventional way. For some locks it may then be more difficult to restore the original situation.

Wooden mechanical puzzles can require special care and storage. For more information, please read Caring for Wood Puzzles.


References:
https://en.wikipedia.org/wiki/Mechanical_puzzle
http://www.indiana.edu/~liblilly/collections/puzzles.shtml