Grashof Double Rocker


This type of Grashof linkage is obtained when the shortest link is the floating link (r3). Both the input and output links have limited ranges of motion that are defined as follows:

Input Link

lower limit: theta2 = theta1 + theta2'

upper limit: theta2 = theta1 + theta2''

where theta2' = acos [ ( r1^2 + r2^2 - ( r3 - r4 )^2 ) / ( 2 * r1 * r2 ) ]

and

theta2'' = acos [ ( r1^2 + r2^2 - ( r3 + r4 )^2 ) / ( 2 * r1 * r2 ) ]

Output Link

lower limit: theta4 = 180 + theta1 - theta4''

upper limit: theta4 = 180 +theta1 - theta4'

where theta4' = acos [ ( r1^2 + r4^2 - ( r3 - r2 ) ^2 ) / ( 2 * r1 * r4 ) ]

and

theta4'' = acos [ ( r1^2 + r4^2 - (r3 + r2)^2 ) / (2*r1*r4) ]

To see animations of this linkage select the links below:


Copyright © 1995 UC Davis Integration Engineering Laboratory
design@iel.ucdavis.edu
Last time modified, 7/18/1996