#$%^&*AU2016250360A120180510.pdf#####P1395AU00 ABSTRACT An apparatus 1, for constraining a device 3 to pivot about a remote centre of motion 5. A humerus-member 7 is mounted to pivot, relative to a torso structure 9, about a shoulder axis 11. A radius-member 13 is mounted to pivot, relative to the 5 humerus-member, about an elbow axis 15. A hand-member 17 is mounted to pivot, relative to the radius-member, about a wrist axis 19 and is, or is fixable or integral to, the device. A functional four-bar linkage 21 includes a humerusconstraint-member 23 mounted to pivot, relative to the humerus-member, about a humerus-constraint axis 25 spaced an elbow-offset distance from the elbow axis. 10 The linkage further includes a radius-constraint-member 27 mounted to pivot, relative to the radius-member, about a radius-constraint axis 29 spaced the elbowoffset distance from the elbow axis and mounted to pivot, relative to the humerusconstraint-member, about an elbow-constraint axis 31 a constraint-offset distance from each of the humerus-constraint axis and the radius-constraint axis. A parallel15 keeping mechanism 33 by which the humerus-constraint-member is held parallel to a notional straight line 35 fixed relative to the torso is provided. Another parallelkeeping mechanism 37 by which the radius-constraint-member is held parallel to a notional straight line 39 fixed relative to the hand-member is provided. There is a guide-member 41. Also provided is a passive mechanical transmission 43 by 20 which two members 7, 13, of the functional four-bar linkage and mounted to pivot about one of the elbow axis and the elbow-constraint axis, are mutually connected, and the guide-member is constrained to move with a notional centerline 45 centered between the two members. A translation mechanism 47 connects the guide-member to, and constrains to move along the notional centerline, the other 25 of the elbow axis and the constraint axis.
