A mechanism is the part of a machine which contains two or more pieces arranged so that the motion of one compels the motion of the others Generally used to Change the direction of movement Change the type of movement ID: 1025001
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1. Mechanisms
2. What is a Mechanism? A mechanism is the part of a machine which contains two or more pieces arranged so that the motion of one compels the motion of the others. Generally used to:Change the direction of movementChange the type of movementChange the speed of movementChange the amount of torque or force available to do work
3. Mechanism MovementRotaryLinearReciprocating Oscillating
4. Universal JointAngular Range > 90˚ and < 270˚Speed and Torque constantRatio 1:1Flow of Power reversible Input & Output Shafts same direction
5. Where Can You Find a Universal Joint?Drive shaft of vehiclesPower take-offwww.rqriley.com/imagespln/pattersn_ujoint.jpgUniversal joints are used to transmit rotary movement at an angle that is not 90°.
6. Bevel Gear90˚ AngleSpeed and Torque constantGear Ratio 1:1Flow of Power reversible
7. Where Can You Find a Bevel Gear?The bevel gear is used to change rotational motion at a 90˚ angle.Using gears with differing numbers of teeth will change the speed and torque.Hand drillCar differentialShaft-driven bicycle
8. Simple Gear Train with IdlerInput and Output Shafts parallelSpeed is decreasedTorque is increasedRatio 4:1Flow of Power reversibleInput and Output Gears same directionWithout Idler Gear different directionIDLER GEAR
9. Where Do You Find a Simple Gear Train with Idler?Two meshed gears will rotate in opposite directions.An Idler Gear allows the drive and driven gears to rotate in the same direction.Paper Transport Rollers
10. Worm and Wheel90˚ AngleSpeed is decreasedTorque is increasedGear Ratio 20:1 Flow of Power NOT reversibleDirection of Travel reversible
11. Where Do You Find a Worm and Wheel?A worm is used to reduce speed and increase torque. The motion is not reversible; a gear cannot drive a worm.Tuning mechanism on string instrumentsElectric motorsWinch
12. Crown and Pinion90˚ AngleSpeed is decreasedTorque is increasedGear Ratio 3.2:1Flow of Power reversibleDirection of Travel reversible
13. Where Do You Find a Crown and Pinion?WatchesCarouselDVD playerHow many crown and pinion gears do you see in this pendulum clock?
14. Rack and PinionInput Movement rotaryOutput Movement linearDistance is 2 in.With a Larger Pinion Gear - the rack will move a longer distanceFlow of Power reversibleDirection of Travel reversible
15. Where Do You Find a Rack and Pinion?Used to convert between rotary and linear motion.Provides gear reduction to make it easier to turn the wheels.Used in steering systems of cars to convert rotary motion of steering wheel to the side to side motion in the wheels.Rack and pinion steeringRackPinion
16. Pulley and BeltInput and Output Shaft parallelSpeed is increasedTorque is decreasedRatio 1:2.5Flow of Power is reversibleOpen Belt wheels turn in same directionCrossed Belt wheels turn in opposite direction
17. Where Do You Find a Pulley and Belt?Lawn mowerCar engineBELTS
18. Cam and FollowerInput Movement rotaryOutput Movement reciprocatingFollower moves up and down 1 time for every revolution of the crankFlow of Power Not reversibleDirection of Travel reversibleCAMFOLLOWER
19. Where Do You Find a Cam and Follower?As a cam rotates, the flat follower is raised and lowered, converting rotary motion to reciprocating (back and forth) motion.Cam shaft
20. Lead Screw (important gear, but you cannot make with Legos)Input Movement rotaryOutput Movement linear6 Revolutions = 1 in.Flow of Power NOT reversibleForce is IncreasedDirection of Travel reversible
21. Where Do You Find a Lead Screw?JackViceChanges rotary movement into linear movementSignificantly increases forceA person can put a little force into turning the handle to move a heavy car.
22. Crank and Slider (another important gear you cannot make with Legos)Input Movement rotaryOutput Movement reciprocatingIncreased Crank increased distance slider movesFlow of Power not reversible
23. Where Do You Find a Crank and Slider?Steam trainInternal combustion engine
24. Image ResourcesMicrosoft, Inc. (2008). Clip Art. Retrieved November 25, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx