Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2003-05-23
2004-09-21
Mullins, Burton (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C160S16810P, C310S093000, C310S152000, C188S267000
Reexamination Certificate
active
06794778
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to motorized window coverings, awnings, security screens, projection screens, and the like, which are being moved against a force that is resisting the repositioning, such as gravity, a counterbalance or a preload spring.
BACKGROUND OF THE INVENTION
The present assignee has provided several systems for either lowering or raising a window covering, or for moving the slats of a window covering between open and closed positions, under control of a hand-held remote or other control device. These systems include a motor that is coupled through gears to the window covering activation mechanism. When the motor is energized in response to a user command signal, the activation mechanism moves the window covering.
As recognized herein, when no power is applied to the motor, a force (such as gravity) acting on the object being repositioned, particularly in the case of large objects, can be sufficient to overcome the inertia, stiction, and frictional drag of the power train components and cause the object to move without user command. Past efforts to eliminate such undesired movement include using solenoids that can be energized to hold the object at the last position commanded by the user or to operate a ratchet pawl that holds the object being repositioned. Unfortunately, such solenoids not only significantly add to the cost of the window covering, but also consume electrical power, a critical shortcoming in the case of battery-powered systems, and objectionable in systems powered by a public utility, since they either must be powered any time the window covering is not actually in operation, consuming considerable energy, or they must be powered during operation of the window covering significantly increasing the power required during operation. Inefficient gearing can prevent repositioning, but at the cost of additional power required to operate. The present invention understands that the above principles apply not only to raisable and lowerable window coverings such as shades, but also to projector screens and other objects that can be repositioned by a motor by raising or lowering the objects by, e.g., rolling and unrolling the objects.
SUMMARY OF THE INVENTION
A powered assembly includes an object that can be moved between a raised configuration and a lowered configuration. The assembly also includes a motor, an actuator coupled to the motor and the object to move the object when the motor is energized, with the motor and actuator defining a rotating member. A permanent magnet is affixed to one of: the rotating member, and a stationary element juxtaposed with the rotating member, while at least one of: a permanent magnet, and a magnetic element that is not a permanent magnet, is juxtaposed with the permanent magnet.
In preferred non-limiting embodiments, the motor may be powered by at least one de battery and the object may be a window covering. The rotating member may be at least a portion of a rotor of the motor.
At least one permanent magnet may be attached to the rotating member, and a magnetic element that is not a permanent magnet may be stationarily juxtaposed with the rotating member. Or, a permanent magnet may be stationarily juxtaposed with the rotating member. The magnet or magnetic element that is stationarily juxtaposed with the rotating member may define a racetrack shape, or a circular shape, or a square shape, and it may include both permanent magnet and magnetic portions.
In another aspect, a drive assembly for a movable object including a rod includes an electrically-powered drive structure couplable to the rod to move the object when the drive structure is energized to move at least one rotatable component of the drive structure. A first braking magnet is attached to one of: a rotating component of the drive structure, and a stationary component of the drive structure. Also, at least one of: a second braking magnet, and a magnetic element that is not a permanent magnet, is attached to the other of: the stationary component, and the rotatable component such that the weight of the window covering is substantially impeded from moving the rod when the drive structure is de-energized.
In another aspect, a power assembly for an object having at least one operator includes power means, motor means energized by the power means, and means for coupling the motor means to the operator. Magnetic means are provided on the motor means and coupling means for braking the object when the motor means is de-energized.
The details of the present invention, both as to its construction and operation, can best be understood in reference to the accompanying drawings, in which like numerals refer to like parts, and which:
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Scharf Rich
Schmeling Dave
Walker Winston G.
Harmonic Design Inc.
Mullins Burton
Rogitz John L.
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