Abstract: A method of controlling a brushless DC motor of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetized material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor. The method comprises the steps of driving current through the stator winding to generate a stator magnetic field to interact with the rotor magnetic field, detecting rotor position with respect to the stator, and cyclically commutating the stator winding current according to rotor position as the rotor rotates. Each commutation cycle includes a drive portion during which current is driven through the stator winding in one sense and at the end of which the driving of current in said sense is ceased.

Abstract: A frame includes longitudinal members secured to one another. The longitudinal members support a spline that is normally open in a first position to provide a cavity. A fabric, such a mesh screen, is arranged over the frame so that the perimeter of the screen is received within the cavities of the longitudinal members. A movable platen is actuated to engage the spline. The splines are forced into the cavities to a second position in which the perimeter of the screen is pinched between the splines and the longitudinal members. A radius nose of the splines is retained in a channel of the longitudinal members securing the screen without tearing it when under load.

Abstract: A method of controlling a brushless DC motor of the type having a stator, comprising a stator winding excitable to generate a stator magnetic field, and a rotor, arranged to rotate with respect to the stator and comprising permanently magnetised material arranged to generate a rotor magnetic field to interact with the stator magnetic field to produce rotation of the rotor. The method comprises the steps of driving current through the stator winding to generate a stator magnetic field to interact with the rotor magnetic field, detecting rotor position with respect to the stator, and cyclically commutating the stator winding current according to rotor position as the rotor rotates. Each commutation cycle includes a drive portion during which current is driven through the stator winding in one sense and at the end of which the driving of current in said sense is ceased.

Abstract: A frame includes longitudinal members secured to one another. The longitudinal members support a spline that is normally open in a first position to provide a cavity. A fabric, such a mesh screen, is arranged over the frame so that the perimeter of the screen is received within the cavities of the longitudinal members. A movable platen is actuated to engage the spline. The splines are forced into the cavities to a second position in which the perimeter of the screen is pinched between a corner of the splines and the longitudinal members. A nose of the splines, which includes the corner, is retained in a channel of the longitudinal members.

Abstract: A frame for a window screen assembly is provided that uses corner locks to secure the rails and stiles. Interlocking features provided by the corner locks are used to secure the corner locks to the rails and stiles. A method of securing screens to different sized frames using a three-stage operation is disclosed. Adhesive and a movable flange are used to secure the screen to the frame in one disclosed embodiment.