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ENGR 107 – Introduction to Engineering
Simple Machines and Mechanical Advantage (Lecture #4) ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Simple Machines ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Simple Machines A mechanical device that changes the magnitude or direction of a force. ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Simple Machines The six classical simple machines are: Lever Wheel and axis Pulley Inclined plane Wedge Screw All complex machines are constructed from one or more of these simple machines. ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Simple Machines Simple machines can be classified as follows: Those dependent on the vector resolution of forces Inclined plane Wedge Screw Those in which there is an equilibrium of torques Lever Pulley Wheel ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Lever ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Wheel and Axle ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Pulley ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Inclined Plane ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Wedge ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Screw ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Simple Machines A simple machine uses an applied force to do work against a load. Work done on the load is equal to the work done by the applied force. Can be used to increase the force acting on the load, at the expense of a proportional decrease in the distance that the load is moved. The ratio of the force acting on the load to the force applied to the simple machine is known as the mechanical advantage. ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Mechanical Advantage ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Mechanical Advantage The factor by which a simple machine multiplies the force or torque applied to it. ENGR Introduction to Engineering
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MA = output force / input force
Mechanical Advantage MA = output force / input force applied force force acting on load ENGR Introduction to Engineering
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MA = distanceapplied force / distanceload moved
Mechanical Advantage MA = distanceapplied force / distanceload moved ENGR Introduction to Engineering
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Mechanical Advantage WorkIN = WorkOUT
Force applied x distanceapplied force = Force acting on load x distanceload moved ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Lever ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Pulley ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Pulley r1 r2 input output ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Torque (Moment) The tendency of a force to rotate an object about an axis, fulcrum or pivot. ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Torque (Moment) ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Torque T = F x d d = Distance measured from the point of rotation to the applied force F = applied force perpendicular to the measured distance ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Mechanical Advantage MA = T2 / T1 = r2 / r1 output input output input T = torque r = radius ENGR Introduction to Engineering
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T2 = MA x T1 F2 x d2 = MA x (F1 x d1) F2 = MA x F1 x (d1 / d2)
Mechanical Advantage T2 = MA x T1 F2 x d2 = MA x (F1 x d1) F2 = MA x F1 x (d1 / d2) ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Gears ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Gears ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Gears Gears may be considered a simple machine. Two or more gears working in tandem can produce a mechanical advantage. Gear ratio Unequal number of teeth Gears in a transmission are analogous to wheels in a pulley. ENGR Introduction to Engineering
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MA = T2 / T1 = #Teeth2 / #Teeth1
Mechanical Advantage MA = T2 / T1 = #Teeth2 / #Teeth1 output input output input T = torque #Teeth = # of teeth on gear ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Velocity Reduction ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Velocity Reduction VR = 1 / MA ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Velocity Reduction VR = T1 / T2 = r1 / r2 input output T = torque r = radius ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Pulley r1 r2 input output ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Gears r1 r2 input output ENGR Introduction to Engineering
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Angular Speed A measure of the speed of rotation about an axis.
Often specified in revolutions per minute (rpm). ENGR Introduction to Engineering
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ENGR 107 - Introduction to Engineering
Angular Speed w2 = VR x w1 output input w1 = angular speed of input wheel or gear w2 = angular speed of output wheel or gear ENGR Introduction to Engineering
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