A link assembly comprising: a. a pair of mechanical links (81, 82) pivotally connected to rotate relative to one another about a pivot axis; b. a cup with an end wall which defines a first end of a winding chamber, and an annular side wall which extends from the end wall and defines a side of the winding chamber; c. a lid which defines a second end of the winding chamber opposite to the first end, wherein the lid is coupled to the cup by a bearing (21, 11) so that the cup and lid can rotate with respect to each other; d. an opening in the side wall of the cup, characterised in that the link assembly further comprises: e. a slot in the lid; f. a cable having a length, a width, and a thickness, wherein the width of the cable is greater than its thickness, and the cable comprises: i. a first portion which extends along a first one of the links and passes into the side of the winding chamber through the opening in the side wall of the cup, ii. a second portion which extends along a second one of the links and passes into the second end of the winding chamber through the slot in the lid, and iii. a rolled portion in the winding chamber in which the cable is wound into a roll, the roll including an outer turn which leads to the first portion and an inner turn which is inside the outer turn and leads to the second portion; and in that: the cup further comprises a cable guide which defines a cable channel extending tangentially away from the opening in the side wall of the cup and away from the winding chamber; and the first portion of the cable passes into the winding chamber through the cable channel, wherein the first portion of the cable is secured to the cable guide by a fastener passing through the cable portion and through holes in the walls of the guide. a. a pair of mechanical links (81, 82) pivotally connected to rotate relative to one another about a pivot axis; b. a cup with an end wall which defines a first end of a winding chamber, and an annular side wall which extends from the end wall and defines a side of the winding chamber; c. a lid which defines a second end of the winding chamber opposite to the first end, wherein the lid is coupled to the cup by a bearing (21, 11) so that the cup and lid can rotate with respect to each other; d. an opening in the side wall of the cup, characterised in that the link assembly further comprises: e. a slot in the lid; f. a cable having a length, a width, and a thickness, wherein the width of the cable is greater than its thickness, and the cable comprises: i. a first portion which extends along a first one of the links and passes into the side of the winding chamber through the opening in the side wall of the cup, ii. a second portion which extends along a second one of the links and passes into the second end of the winding chamber through the slot in the lid, and iii. a rolled portion in the winding chamber in which the cable is wound into a roll, the roll including an outer turn which leads to the first portion and an inner turn which is inside the outer turn and leads to the second portion; and in that: the cup further comprises a cable guide which defines a cable channel extending tangentially away from the opening in the side wall of the cup and away from the winding chamber; and the first portion of the cable passes into the winding chamber through the cable channel, wherein the first portion of the cable is secured to the cable guide by a fastener passing through the cable portion and through holes in the walls of the guide. i. a first portion which extends along a first one of the links and passes into the side of the winding chamber through the opening in the side wall of the cup, ii. a second portion which extends along a second one of the links and passes into the second end of the winding chamber through the slot in the lid, and iii. a rolled portion in the winding chamber in which the cable is wound into a roll, the roll including an outer turn which leads to the first portion and an inner turn which is inside the outer turn and leads to the second portion; and in that: the cup further comprises a cable guide which defines a cable channel extending tangentially away from the opening in the side wall of the cup and away from the winding chamber; and the first portion of the cable passes into the winding chamber through the cable channel, wherein the first portion of the cable is secured to the cable guide by a fastener passing through the cable portion and through holes in the walls of the guide. the cup further comprises a cable guide which defines a cable channel extending tangentially away from the opening in the side wall of the cup and away from the winding chamber; and the first portion of the cable passes into the winding chamber through the cable channel, wherein the first portion of the cable is secured to the cable guide by a fastener passing through the cable portion and through holes in the walls of the guide.