Patent ID: 8109171

Claim:
A parallel mechanism comprising: arms each being swingably pivotable on a base end portion and each including a pair of rods aligned in parallel in a longitudinal direction thereof; a bracket having an end effecter attached thereto, the bracket being retained between the pair of rods at a free end portion of the arms; a pair of ball joints for displaceably connecting the bracket with the arms, the ball joints each including a first joint element having a ball and provided to one of the pair of rods and the bracket, and a second joint element having a socket for retaining the ball and provided to the other of the pair of rods and the bracket; a connecting member for connecting the parallel rods, and for completely restricting rotation of each rod about an axis that is parallel to the longitudinal direction of the rod; and a biasing member for providing a biasing force for retaining the balls in the sockets at the ball joints.