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RATCHET MECHANISMS | |
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A ratchet mechanism is a toothed wheel and a pawl. As the ratchet wheel turns, the pawl falls into the 'dip' between the teeth. The ratchet wheel can only turn in one direction - in this case anti-clockwise. |
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SIMPLIFIED ANIMATION | |
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The water well seen below has a ratchet mechanism that allows the person to rotate the handle in an anticlockwise direction. The bucket of water is heavy and so the person can rest by taking his/her hands away from the handle. This is because the pawl has fallen into the 'dip' between the teeth and so the bucket cannot fall back into the well. Ratchet mechanisms are very useful devices for example, they are used in mechanical clocks. They are also very useful when using a system, such as the one seen opposite, to lift heavy weights. |
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THE ANIMATION BELOW SHOWS THE REALISTIC SIZE OF A RATCHET AND PAWL MECHANISM, IN PLACE. | |
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You are to design a ratchet mechanism to fit in the back of a delivery van. This system will be used to lift heavy packages from the van to ground level. Use drawings and notes to explain your design. |
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