Users/Telanoc/Gears

A Beginners Guide to Gearbox Design

Notation Conventions:

• A shaft location will be denoted by its row and column, for example 8C is the top row, third from left
• When discussing gear ratios a “/” denotes one gear that meshes with and turns another. For example 5/3
• When discussing gear ratios a “*” denotes two gears that share a single shaft. For example 3*5
• An example would be 5/3*6/5/3. This means a 5 tooth gear turning a 3 tooth gear. On the same shaft as that 3 tooth on a different layer is a 6 tooth gear, which turns a 5 tooth gear, which the turns a 3 tooth gear

The Rules and Concepts

• Every gearbox must start at “1A” (the lower left hand corner as you face the gearbox)
• Every gearbox must have at least one, but no more than three outputs in the top row (Row 8)
• You may use up to, and no more than, thirty (30) gears in your gearbox
• You may use up to, and no more than, fifteen (15) shafts in your gearbox. A shaft is a row and column intersection that has one or more gears (e.g. B2)
• There are three layers in a gearbox. Gears can only mesh when they are on the same layer. The input and output layers don’t matter.
• There are eight rows numbered 1 to 8
• There are eight columns numbered A to H
• Gears come in 1,3,4,5,6, and 7 tooth.
  • 1 tooth is a “Spacer”, and costs no materials.
  • 3 and 4 are considered “Small Gears”, and will cost 2 debens of metal to cast.
  • 5 and 6 are considered “Medium Gears”, and will cost 15 debens of metal.
  • 7 is considered a “Large Gear”, and will cost 100 debens of metal

• The sum of adjacent gears in the horizontal or vertical axis must be 6. Therefore only 3/3 is valid when moving one space in either the horizontal or vertical axis
• The sum of adjacent gears in the diagonal axis must be 8. So 4 and 4, 5 and 3, and 7 and 1 are valid configurations.
• The sum of the gears in the horizontal or vertical axis that are separated by one space (so not adjacent) must be 11. Therefore valid configurations are 6 and 5, 7 and 4
• The sum of the gears in a “Knight’s move”, which is to say two space away and one off the axis, must be 12. Therefore 6 and 6 or 7 and 5 are valid pairs.

• Whenever a gear turns another gear, it is a ratio based on the fraction created from the number of teeth.
  • If a larger fear turns a smaller gear, the output value increases. For example, if a 5 tooth turns a 3 tooth, the output will be increased by 67% because five thirds (5/3) is equal to 1.67.
  • If a smaller gear turns a large gear, the output value decreases. For example, if a 3 tooth turns a 5 tooth, then the output will be 60% of the input because three fifths (3/5) is equal to 0.6.