3. Fixed joints

3.1 Double joint

• Constitution

  This system consists of two cardan joints which are fitted with an internal or external ball joint to ensure that one of the shafts is centered in relation to the other and that the system's break angle θ is distributed almost equally over the two elementary joints. Figure 5 shows such a double joint with a hollow central unitary jaw and two annular crosspieces enabling the use of an internal ball joint. Given the fixed distance between the two joints, perfect homokineticity is achieved only for the zero angle and for an angle θ _c retained at design, where we then have θ _...