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Gears and Gear Systems. Gears. http://www.technologystudent.com/gears1/gears1.htm. Gear ‘A’ has 30 teeth and gear ‘B’ has 20 teeth. If gear ‘A’ turns one revolution, how many times will gear ‘B’ turn ? When gear 'A' completes one revolution gear 'B' turns 1.5 revolutions (1 ½ times)
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Gears http://www.technologystudent.com/gears1/gears1.htm
Gear ‘A’ has 30 teeth and gear ‘B’ has 20 teeth. If gear ‘A’ turns one revolution, how many times will gear ‘B’ turn ? When gear 'A' completes one revolution gear 'B' turns 1.5 revolutions (1½ times) Which gear revolves the fastest ? 1 2
http://www.technologystudent.com/gears1/grdetail.htm Gear details The pitch point is the point where gear teeth actually make contact with each other as they rotate.
Gear Train http://www.technologystudent.com/gears1/gears2.htm This is a good example of a ‘gear train’. A gear train is usually made up of two or more gears. The driver in this example is gear ‘A’. If a motor turns gear ‘A’ in an anticlockwise direction;Which direction does gear ‘B’ turn ?Which direction does gear ‘C’’ turn ?Does gear ‘C’ revolve faster or slower than gear ’A ? - explain your answer So far you have read about ‘driver’ gears, ‘’driven’ gears and gear trains. An ‘idler’ gear is another important gear. In the example below gear ‘A’ turns in an anticlockwise direction and also gear ‘C’ turns in an anticlockwise direction. The ‘idler’ gear is used so that the rotation of the two important gears is the same.Is the speed of gears A and B the same ?
http://www.technologystudent.com/gears1/gears2.htm It would be very difficult to draw gears if you had to draw all the teeth every time you wanted to design a gear system. For this reason a gear can be represented by drawing two circles.
Rack and Pinion http://www.technologystudent.com/gears1/gears4.htm A ‘rack and pinion’ gears system looks quite unusual. However, it is still composed of two gears. The ‘pinion’ is the normal round gear and the ‘rack’ is straight or flat. The ‘rack’ has teeth cut in it and they mesh with the teeth of the pinion gear.If gear ‘A’ rotates how would you describe the movement of the rack ?
The basics - Gears http://www.technologystudent.com/gears1/gearat1.htm Many machines use gears. A very good example is a bicycle which has gears that make it easier to cycle, especially up hills. Bicycles normally have a large gear wheel which has a pedal attached and a selection of gear wheels of different sizes, on the back wheel. When the pedal is revolved the chain pulls round the gear wheels at the back. Look at the gear wheel with the pedal attached and compare it in size to the gear wheels in the centre of the back wheel. What do you notice about them?
The reason bicycles are easier to cycle up a hill when the gears are changed is due to what is called Gear Ratio (velocity ratio). Gear ratio can be worked out in the form of numbers and examples are shown below. Basically, the ratio is determined by the number of teeth on each gear wheel, the chain is ignored and does no enter the equation. If the pedal gear revolves once how many times will the sprocket gear revolve?
