Spiral balance device

A coupling 3 rotatably mounted at the bottom of a tube 1 through which a spiral rod 5 projects. A torsion spring 11 fixed to the coupling 3 and fixed within the upper end of the tube in which is fixed a fixing member 14 and an adjustment member 17 rotatably mounted in the tube. The adjustment member 17 having projection 21 engageable by the spiral rod. A ratchet mechanism, e.g. abutting teeth, between fixing member and adjustment member allow rotation in a direction of spring tensioning and prevents rotation of the adjustment member in direction of unwinding torsion spring. Pre-tensioning of spring can be applied by rotating the spiral rod at the free end 7, thus rotating the coupling 3, wherein ratchet mechanism may make a 'clicking' sound. Excessive tension can be released by pulling the spiral rod to disengage it from the adjustment member 17.