It is often inconvenient to use long trains of gears to transmit force from one location to another. An alternative transmission design uses a chain to connect the motor and hub instead. In this mini-project, you will develop a fan with a more convenient design that uses chains and sprockets instead of a gear train. Fan with Chain and Sprockets
Materials Needed
Step 1: Build the Chain and Sprocket Fan
Modify the fan according to the following diagrams with the chain and sprocket. Tip: It is easier to tighten the top brackets first, put the chain around both sprockets, then adjust the height and tighten the bottom brackets to the extrusion.
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Chain and Sprockets (1/6)
Chain and Sprockets Page 1
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Step 2: Start the SRS Programmer
Follow the instructions to start the SRS Programmer.
1. Switch the SRS Programmer to "ON." 2. Press the "Test" button twice. 3. Then press any directional button to spin the fan left or right.
SRS Programmer
Using the Rev Chain Tool
Step 3: Observe
The chain transmits motion from the motor sprocket (bottom) to the hub sprocket (top) to generate a working fan.
Did You Know? Loose and Tight Chains
When installing the chain, note that the chain should have a snug fit. Loose chains and tight chains can be damaging to the chains, sprockets, and overall structure.
Loose ChainTight Chain
Try It! Faster Sprocket Fan
Replace the top sprocket with a 15-tooth sprocket. How will that effect the speed and torque of the fan? Attach smaller sprocket on top of the fan
What happens?
Did You Know? Gear Ratios with Sprockets
Sprockets also have gear ratios, as they are essentially the equivalent of gears in a chain or belt drive system. A sprocket is a toothed wheel that is designed to mesh with a chain or belt to transmit power from one shaft to another.
Gear Ratio with Sprockets
The gear ratio of a sprocket system is determined by the number of teeth on the sprockets. Similar to gears, the gear ratio of a sprocket system is calculated by dividing the number of teeth on the driven sprocket by the number of teeth on the driving sprocket.
Try It! Stronger Sprocket Fan
Rearrange the sprockets so that the 15-tooth sprocket is attached to the motor and the 40-tooth sprocket is attached to the hub of the fan at the top. How will this design effect the speed and torque? Rearrange big and small sprockets
What happens?
Did You Know? Compound Gear and Sprocket
To make a compound gear with a gear and a sprocket, you would need to mount the gear and sprocket on the same shaft. Compound Gear and Sprocket
When designing a compound gear with a gear and sprocket, it's important to ensure that the gear ratio is calculated correctly. The gear ratio of the compound gear will depend on the number of teeth on the gear and the number of teeth on the sprocket that are in mesh with each other. The gear ratio is calculated by dividing the number of teeth on the driven sprocket by the number of teeth on the driving gear.
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