Abstract: A joint locking mechanism comprising a latch assembly and a gear movable relative to the latch assembly and comprising gear teeth. The latch assembly comprises an actuator moveable between a withdrawn position and a deployed position; first and second latches, each comprising an engagement element adapted to interlock with the gear teeth, each being moveable between an unlocked position and a locked position; a pivotable coupling comprising a first end coupled to the first latch, a second end coupled to the second latch, and a pivot positioned between the first and second ends which is rotatably coupled to the actuator. When the actuator is in the withdrawn position both the first and second latches are in the unlocked position. Movement of the actuator from the withdrawn position to the deployed position causes one, but not both, of the first and second latches to move to the locked position.

Abstract: An arm device comprising a universal joint, which universal joint comprises a first wrist joint, a second wrist joint and a first elbow joint wherein: each wrist joint comprises a first part, a second part and a slipring, which slipring comprises a rotor coupled to the first part and a stator coupled to the second part, which rotor is coaxially engageable with the stator and infinitely rotatable relative to the stator such that: the first part of the first wrist joint is infinitely rotatable relative to the second part of the first wrist joint about a first axis, and the first part of the second wrist joint is infinitely rotatable relative to the second part of the second wrist joint about a second axis; the first elbow joint comprises a first portion and a second portion, which first portion is rotatably engageable with the second portion about a third axis; the first wrist joint is coupled to the first elbow joint; and first elbow joint is coupled to the second wrist joint.