Pointing mechanism with two independant rotation movements and no dead-centre

摘要

The Cardan mechanism is extended by the addition of a further coupling to ensure full movement without dead point. The mechanism has two rotational movements about independent x- and y-axes, turning through angles alpha and beta . It is based on a classical Cardan suspension in which the y-axis is able to pivot about the x-axis by an angle alpha . The mechanism further includes a provision to allow the x-axis to pivot about the y-axis by a third angle gamma . The mechanism includes a coupling between the two articulations (Q,A) controlling these rotational movements. This ensures that the angles alpha and gamma are equal.