Gear Theory
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http://www.technologystudent.com/gears1/geardex1.htm
This activity familiarizes students with gears of different sizes and how these relate. There are excellent mathematics connections, such as relating the number of times a small gear turns to that of a larger gear. Students can also compare circumferences. Students should discover the ratio of gear teeth, such as 8 teeth on the smaller gear and 40 on the larger gear, means that the small gear must turn 5 times to move the larger gear once. You might ask students to create a table and record their results.
Brain Pop Ballston /Scotties Gears
Gears
Gears are toothed or pegged wheels meshed together to transmit motion and force. In any pair of gears the larger one will rotate more slowly than the smaller one, but will rotate with greater force. Each gear in a series reverses the direction of rotation of the previous gear.
Wheel Diameter Formula for Circumference Circumference of the wheel 1 2pi x r or pi x d 3.141 1 1/2 where pi = 3.14159 4.712 2 d= diameter of wheel 6.283 2 1/2 r = radius of wheel 7.853 3 9.424 3 1/4 10.210 3 1/2 10.995 3 3/4 11.780 4 12.566 http://www.technologystudent.com/gears1/gears1.htm
Gear 1 Gear 2 distance between centers 12 20 5/8" 12 30 13/16" 12 40 1" 20 30 1" 20 40 1 3/16" 30 40 1 3/8" Combinations from the following gears 12t, 20t, 30t & 40t
2 gears in combination - [Driver:Driven]
12:20 3:5 12:30 2:5 12:40 3:10 20:12 5:3 20:30 2:3 20:40 1:2 30:12 5:2 30:20 3:2 30:40 3:4 40:12 10:3 40:20 2:1 40:30 4:3 http://www.technologystudent.com/gears1/gears2.htm
Another look at Compound Gears
http://www.technologystudent.com/gears1/gears3.htm
Compound gear Calculator
4 gears in combination 12:20 ; 30:40 = 3/5 x 3/4 = 9/20 or 9:20 the 20t and 30t are on the same "axle"
12:20; 30:40 9:20 20:12; 30:40 5:4 30:12; 20:40 5:4 40:12; 20:30 20:9 12:20; 40:30 4:5 20:12; 40:30 20:9 30:12; 40:20 5:1 40:12; 30:20 5:1 12:30; 20:40 1:5 20:30; 12:40 1:5 30:20; 12:40 9:20 40:20; 12:30 4:5 12:30; 40:20 4:5 20:30; 40:12 20:9 30:20; 40:12 5:1 40:20; 30:12 5:1 12:40; 20:30 1:5 20:40; 12:30 1:5 30:40; 12:20 9:20 40:30; 12:20 4:5 12:40; 30:20 9:20 20:40, 30:12 5:4 30:40; 20:12 5:4 40:30; 20:12 20:9 http://www.technologystudent.com/gears1/pulley2.htm
Our Pulleys for class project:
Pulley 1 Pulley 2 Pulley 3 Pulley 4 3/8 diameter (0.375) 6/8 diameter (0.750) 9/8 diameter (1.125) 12/8 diameter (1.500) Distance Between Pulleys
Pulley A Pulley B Distance 1 2 2.375 inches 1 3 2.125 inches 1 4 1.750 inches 2 3 1.750 inches 2 4 1.375 inches 3 4 1.375 inches Speed Chart Circumference is pi (3.14159) x Diameter
Device How Far Unit Motor 11000 RPM's Drive Wheel 1.5 inches diameter Drive Wheel 1 turn 4.71 inches Drive Wheel 51810 Inches Per Minute Drive Wheel 4317.5 Feet Per MInute Drive Wheel 0.8177083 Miles Per Minute Drive Wheel 49.0625 Miles Per Hour