Figure 1 depicts the principle layout of a 4-bar linkage which can
be used to move a piston of an engine along a straight line. Point 4 in
this figure is uch a point which moves almost exactly along a straight
vertical line by an amount equal to the Figure 1 : Principle layout of 4-bar linkage
To give you a feeling for the range of curves (orbits) point 4 moves on as the crank ( center at point 0 ) rotates once around click on the following links : oval , ovals with cusps , ovals with "ears" , leaning double-8 , double-8 with vanishing waist , and perfect double-8 orbit. Program 4bar can do one of two things for you by filling out the boxes either on the left or right below. On the left side - labeled "Find an optimal Configuration ...." - you provide the smallest amount of information the program needs to determine the remaining parameters. On the right hand side - labeled "Or enter your values ...." - the program will determine the orbit of point 4 for your configuration. Sample Input for Optimization : Desired stroke 10 ratio e/a 0.4 x4_diff 0.1Result from program : r 0-1 4.188803 a 18.689442 b 11.822348 c 2-3 18.925111 d 1-3 12.010892 e 4-5 7.475779 f 3-5 0.075418 Vbox 16.930246 Hbox* 25.934334 Stroke 10.000000Nobody can machine the various parts exactly to the demanded dimensions. But you can check now what happens if you round the above numbers and re-enter them as your configuration : r 0-1 4.200000 a 18.700000 b 11.800000 c 2-3 18.900000 d 1-3 12.000000 e 4-5 7.500000 f 3-5 0.100000The program gives you back the following information : Vbox 16.979104 Hbox* 25.928940 Stroke 10.028491 x4_diff 0.124848and you have to judge whether you can live with that. |

Last revised: 01/24/15