Electrical window operator

A window operator for opening and closing a window having a generally rectangular main frame and a generally rectangular sash mounted for pivoting movement relative to the main frame about a pivot axis generally parallel to a pair of opposed sides of said sash, comprising:

• at least one arm connected pivotally in a first end with a first coupling member connected with one of said opposed sides of the sash and at the other end with a second coupling member connected with a side of said main frame located opposite said one opposed side of the sash, at least one of said pivotal connections of said one and other ends of said arm with said first and second coupling members, respectively forming a detachable coupling,
• an operator housing arranged at one side of the main frame and accommodating an elongate rotatable drive shaft with a threaded section of a predetermined length, said second coupling member comprising a nut element engaging said threaded section of the drive shaft to be longitudinally displaceable within said predetermined length thereof by rotation of the drive shaft, and an electrical drive unit comprising a motor and transmission means arranged in said operator housing in axial extension of said drive shaft for rotation of said shaft in one or the other direction of revolution.