Patent ID: 7740553

Claim:
An apparatus having a left adjustable member and a right adjustable member, comprising: a moveable member coupled to said left adjustable member and said right adjustable member such that when said moveable member is rotated in a clockwise direction said left adjustable member and said right adjustable member are moved apart and when said moveable member is moved in a counter clockwise direction said left adjustable member and said right adjustable member are moved closer together; and a belt coupling said movable member to a mechanism, wherein said mechanism converts rotation of said belt into coordinated motion of said left adjustable member and said right adjustable member so that said left adjustable member and said right adjustable member move the same distance in opposite directions wherein said mechanism includes a tensioner member and a clamp member, said tensioner member and said clamp member positioned to engage opposing surfaces of said belt, said tension member moveably mounted such that said tensioner member can rotate and is biased toward said clamp member, so that said tension member causes said left adjustable member and said right adjustable member to back off a controlled amount when said moveable member is released.