Presentation on theme: "Application of Four-Bar Mechanisms in Cars"— Presentation transcript:
1 Application of Four-Bar Mechanisms in Cars Windshield WiperSoft Top MechanismGroup AChristopher BackJosephashwin FranklinKwongvoon WongChen Lin
2 Components of Soft Top Mechanism Cascading Four-bar MechanismsOpen Loop Four-bar ConfigurationUsed in Industrial robotsUsually requires multiple actuators to control motionPantograph LinkageOriginally used in scaled diagramsLinkages consist of Parallelograms
7 Windshield Wiper Mechanism The four-bar linkage has been show as the simplest possible pin-jointed mechanismAllows for single degree of freedom controlled motion
8 Variations of the Crank-Rocker in Windshield Wipers Grashof ConditionS+L<P+QClass I case:Ground either link adjacent to the shortest and you get a crank-rockerThe shortest link will fully rotatethe other link pivoted at the ground will oscillate
9 Tandem system Tandem system is widely used in the front windshield One Motor runs both wipersParallelogram linkage translates motion to wipers
10 Most Common Type of Windshield mechanism DOF= 3*(6-1)-2*7=1Four and Six-bar is a parallelogram linkage.Duplicate the rotary motion of the driver crank at the driven bar.
11 Crank Rocker Input to Windshield Wiper The coupler of the parallelogram linkage is in curvilinear translationRemaining at the same angle while all points on it describe identical circular paths
14 Window Single Arm The slider-crank mechanism Variations of grounding different linksInversion D
15 Diagram of Rear Wiper DOF = 3*(4-1)-2*4= 1 We can imagine that the coupler link length is very smallHow is the condition when driver link length change?
16 The Next Generation of Wipers Flexblade(TM) Wiper .Its life can extend from months to yearsThe four-bar linkage mechanism will still be used in this wiper system for a long time
17 ReferencesHow Windshield Wipers Work. (2006) In: How Stuff Works Available: <http://auto.howstuffworks.com/wiper2.htm> [2007, October 12].Norton, R.L. Design of Machinery: An Introduction to the Synthesis and Analysis of Mechanisms and Machines. 3rd ed. New York, McGraw-Hill CoHow soft top convertible works. (2006) In: How Stuff Works Available: <http://auto.howstuffworks.com/wiper2.htm> [2007, October 12].Pantographs.(2006) In: Wikipedia The Free Encyclopedia:<http://en.wikipedia.org/wiki/Pantograph> [2007, October 12].