Balance assembly for a window

A balance assembly adapted to be positioned in a side jamb of a window frame comprising:

• an elongated housing having enclosing sidewalls and a back wall,
• a gas pressurized cylinder and piston assembly wherein said piston has one end partially enclosed within said cylinder and in which said piston is reciprocally movable within said enclosing sidewalls of said elongated housing,
• said cylinder and piston assembly being adapted to oppose said reciprocal movement,
• a first pulley assembly fixed to the end of said piston opposite said enclosed end,
• said first pulley assembly having a plurality of grooved pulley wheels and having a shaft forming the axis of rotation of said pulley wheels
• a second pulley assembly fixed to the end of said cylinder opposite said enclosed end of said piston,
• said second pulley assembly having a plurality of grooved pulley wheels and having a shaft forming the axis of rotation of said pulley wheels,
• means for locking one of said pulley assemblies against movement within said elongated housing assembly,
• a sash cord connected at one end to one of said pulley assemblies and wound alternately around pulleys of said first and second pulley assemblies with a free end of said sash cord extending through the lower end of said elongated housing, and
• a connector member secured to said free end of said sash cord, said connector being adapted to be connected to a window sash.