Piezo-based encoder with magnetic brake for powered window covering
AssigneeSomfy SAS
InventorsPierre-Emmanuel Cavarec, Winston Glenn Walker
Life of this patent
Estimating the term…
Abstract
The position and speed and, in some embodiments, direction of rotation of a motor for turning the rod of an object such as a window covering is determined by placing a braking magnet next to the motor and a piezoelectric element between the braking magnet and motor. As the motor rotates, the piezoelectric element generates a signal that can be used to determine the speed of rotation and also the position of the motor (and, hence, the position of the object being moved). The magnet brakes the motor from turning under the weight of the object when the motor is deenergized.
Claims17
A powered assembly, comprising:
- at least one object that can be moved between a first configuration and a second configuration, the object being selected from the group consisting of window coverings, awnings, skylight coverings, curtains and screens;
- at least one motor including a rotor and a stator;
- at least one actuator, coupled to the motor and the object, to move the object when the motor is energized;
- at least one magnet mounted on the stator, juxtaposed with the rotor and magnetically coupled thereto;
- and
- at least one piezoelectric element that transfers the force of the magnet to output signals when the rotor rotates, the signals being useful in determining at least one of:
- a position, and a speed of rotation, of the motor, the magnet magnetically braking the rotor from turning when the motor is deenergized.
A drive assembly for a movable object including a rod, comprising:
- an electrically-powered drive structure couplable to the rod to move the object when the drive structure is energized, the drive structure having a motor including a rotor and a stator;
- at least one braking magnet mounted on the stator and closely spaced from the rotor;
- and
- at least one piezoelectric element juxtaposed with the magnet and generating a signal as the rotor moves past the magnet, the signal being representative at least of a position of the rotor.
A method of operating an object that can be moved between a first configuration and a second configuration, the object being selected from the group consisting of window coverings, awnings, skylight coverings, curtains, and screens, the method comprising:
- providing a motor including a rotor and a stator;
- coupling the rotor to the object such that the object is moved when the rotor is energized;
- mounting at least one magnet on the stator and closely juxtaposing the at least one magnet with the rotor;
- using the magnet to brake the drive structure when the rotor is not energized;
- and
- piezoelectrically generating signals when the rotor rotates past the magnets to determine at least one of:
- a position of the rotor, and a speed of the rotor.
Dependencies are inferred from the claim text.