adjusting force in fixed joints?

i have attached three capsules in series with a sphere at the top , all attached through hinge joints.the sphere at the last dosn't use gravity and is kinematic so it is still on which i use a script to move around.bt as soon as the sphere moves out of the capsule length it dosnt stops but the capsule joints feel differences in b/w. i have also try fixed joints in these places but the problem still exists.. please find me a solution. ?