Patent ID: 7574772
Filing Date: 2009-08-18
Classification: E05D,E05Y,Y10T

Abstract:
1. A spring balance comprising a top assembly which is securable to a frame member, a bottom assembly which is securable to a sliding sash, a tension spring connected to the top assembly and to the bottom assembly, a spiral rod connected to one of the top assembly and the bottom assembly, a follower bush mounted upon the spiral rod, and a torsion spring connected to the follower bush and to the other of the top assembly and the bottom assembly, whereby movement of the top assembly relative to the bottom assembly causes movement of the follower bush along the spiral rod and consequent rotation of the follower bush to change torsion in the torsion spring, the spring balance further comprising an adjustment mechanism whereby the torsion in the torsion spring is adjustable, the adjustment mechanism comprising a part of the top assembly, adjustment of the torsion in the torsion spring being effected by way of rotation of said part of the top assembly, the spring balance additionally incorporating a limit mechanism for limiting the rotation of said part of the top assembly and thereby limiting adjustment of the torsion in the torsion spring.