Flexible or portable closure – partition – or panel – Pleating type – With power operating means
Reexamination Certificate
2000-08-18
2001-05-01
Purol, David M. (Department: 3634)
Flexible or portable closure, partition, or panel
Pleating type
With power operating means
C160S008000, C160S171000, C160S296000, C160S308000
Reexamination Certificate
active
06223802
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to control systems for coverings for architectural openings and the like and, more particularly, to a uni-directionally driven pull system that drives a lift cord system for moving the covering between extended and retracted positions.
2. Description of the Relevant Art
Coverings for architectural openings such as windows, doors, archways and the like take numerous forms including conventional draperies, horizontal Venetian blinds, vertical blinds, roll up shades and numerous other coverings that resemble or define modifications of the afore noted standard coverings. The control systems utilized to operate the coverings sometimes vary depending upon the type of covering so that a roll up shade, for example, would normally have a different control system than a vertical blind or a horizontal Venetian blind. Most control systems are operated with pull cords, pull tapes, or tilt wands which hang from an end of a headrail and are manipulated by a human operator to move the covering between extended and retracted positions relative to the architectural opening in which it is mounted. The suspended cords or wands may also tilt slats or vanes in the covering while the covering is extended across the architectural opening so that the slats or vanes can be rotated about longitudinal axes between open and closed positions to permit the passage of vision and light through the covering.
When pull cords or pull tapes are utilized, they are frequently endless thereby defining a loop of cord or tape at one end of the headrail and loops of this type have presented problems in inadvertently causing physical harm to infants and young children who may put a body part within the loop and get caught in the loop.
There has been a considerable amount of activity in recent years designed to remove the inherent danger in endless pull cords to young children and by way of example, the endless cords may be divided into two distinct cords so that no loop is present. The ends of such a divided cord may also be releasably connected so that under predetermined conditions or pressures, the ends of the cord will become separated to avoid harm to an infant.
It is to provide a new and improved approach to the endless cord problem and to provide an otherwise improved control system for a covering for an architectural opening that the present invention has been developed.
SUMMARY OF THE INVENTION
The present invention resides in an unique approach to solving the closed loop pull tape or cord problem by utilizing a single pull tape, cord, or handle as opposed to an endless loop or two adjacent pull tapes or cords to drive the system. The single pull tape, cord, or handle is utilized to drive a uni-directional pull system that intermittently rotates a drive shaft in one direction. The drive shaft can be used in connection with various types of architectural coverings but for purposes of the present disclosure it is described in connection with a covering with lift cords and, more specifically, with a unique lift system in which lift cords associated with the covering are operatively wrapped around spools rotated by the drive shaft to lift a covering from an extended lowered position to a retracted raised position adjacent the top of the architectural opening. Gravity is utilized to lower the covering from the retracted position to the extended position.
The lift system component and the pull system component of the present invention are operatively interconnected to effect the desired operation of the covering. The lift system component cooperates with one or more conventional lift cords that extend through or are adjacent to the sheet or other component of the covering that extends across the opening and are attached to a lower edge or bottom rail of the covering sheet or the like. The lift cords are secured at their upper end to associated cord spools that are rotatably driven by the drive shaft. Each lift cord is fed onto a cord spool tangentially and at an acute angle so that the cord wraps smoothly about the spool when the covering is being raised to its retracted position. The cord spool is mounted for sliding movement along its rotative axis so that the cord can be fed to the spool from a single location and the spool is caused to be slid along its rotational axis by the engagement of each wrap of cord against a previous wrap. A resilient member, such as a spring or a foam bushing, yieldingly resists sliding movement of the cord spool as the cord is being wrapped therearound and serves to return the cord spool to a beginning position as the blind is lowered to its extended position. An outer cylindrical shell surrounds the cord spool and is spaced from the cord spool a distance that is only slightly greater than the diameter of the cord so that the cord is prevented from overlapping itself causing tangling of the cord resulting in a malfunction of the lift system.
The pull system component of the present invention, which in the disclosed embodiment is utilized to rotate the drive shaft that in turn rotates the cord spools, includes a main drive assembly and a clutch/brake assembly. The main drive assembly has a drive spool about which a pull tape or pull cord is wrapped with the drive spool being operatively connected to a spiral spring that biases the drive spool in one direction toward a starting position. For purposes of the present disclosure, the pull element of the system will be referred to as a pull tape even though a pull cord or a handle could also be utilized. The spiral spring is tensioned as the pull tape is extended or unwrapped from the drive spool rotating the drive spool in a first direction from its starting position. The spiral spring serves to automatically return the drive spool to its starting position once the pull tape is no longer being unwrapped and the reverse rotation of the drive spool causes the pull tape to be rewrapped onto the drive spool.
The drive spool is axially aligned with an independent driven member having a diameter slightly less than that of the drive spool. The drive spool and driven member are axially aligned with a cylindrical cavity in a housing for the pull system and a clutch spring cooperates with the drive spool, the driven member and the cylindrical cavity in selectively effecting rotation of the driven member in only the first direction when the drive spool is rotated in the first direction as is caused by an unwinding of the pull tape from the drive spool. Rotation of the drive spool in the opposite or second direction does not drive or rotate the driven member due to the clutch spring. In fact, the driven member is allowed to be freewheeling relative to the drive spool when the drive spool rotates in the second direction so that the alternating direction of rotational movement of the drive spool caused by the unwinding and rewinding of the pull tape affects only uni-directional rotation of the driven member. The uni-directional rotation of the driven member is operative to lift the covering from the extended to the retracted position as will be explained hereafter.
It will be appreciated that, at the end of a drive cycle, as when the pull tape has been fully extended and unwound from the drive spool, the covering will have been lifted a predetermined amount which will typically be less than a full retraction of the covering. To prevent the covering from dropping by gravity during a re-wind cycle, as when the pull tape is being rewound onto the drive spool and the driven member is operatively disconnected from the drive spool, the pull system includes a clutch/brake assembly that selectively prevents rotation of the driven member in the opposite or second direction.
The clutch/brake assembly includes a second spring clutch that is operatively connected to the driven member to grip the driven member when it would otherwise be allowed to rotate in the second direction or the direction in which the covering would drop toward an extended position. The second clutch spring its
Dorsey & Whitney LLP
Hunter Douglas Inc.
Purol David M.
LandOfFree
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