Flexible or portable closure – partition – or panel – Pleating type – With preformed pleats
Reexamination Certificate
2001-04-13
2003-09-23
Purol, David M. (Department: 3634)
Flexible or portable closure, partition, or panel
Pleating type
With preformed pleats
C160S171000
Reexamination Certificate
active
06622769
ABSTRACT:
FIELD OF INVENTION
The invention relates to lift systems for raising and lowering window blinds which have a cord lift system such as pleated shades, roman shades and venetian blinds.
BACKGROUND OF THE INVENTION
Venetian type blinds have a series of slats hung on ladders which extend from a headrail to a bottomrail. In most venetian blinds a pair of lift cords is provided each having one end attached to the bottomrail and then passing through elongated holes in the slats up to and through the headrail. When the lift cords are pulled downward the blind is raised and when the lift cords are released the blind is lowered. A cord lock is usually provided in the headrail through which the lift cords pass. The cord lock allows the user to maintain the blind in any desired position from fully raised to fully lowered. Pleated shades and roman shades are also raised and lowered by lift cords running from the bottom of the shade into a headrail. The cord lock system and other cord lift systems used in venetian blinds can also be used in pleated shades and roman shades.
Another type of lift system for window blinds utilizes a take-up tube for each lift cord. These tubes are contained on a common shaft within the headrail. Each lift cord is attached to one end of a tube. The tubes are rotated to wind or unwind the lift cord around tubes. This system is generally known as a tube lift system. One problem with tube lift systems of the prior art is that the tube may rotate faster than the cord is pulled away from the tube during lowering of the blind. This can occur when one end of the blind is prevented from moving downward as happens when the blind hits a piece of furniture that is too close to the window. That will cause the cord to bunch and often become tangled within the headrail. When this occurs it is usually enough to help the bottomrail with your hand to the bottom most position and then operate again. However, sometimes it is necessary to remove the blind from the window and untangle or replace the tangled lift cord. This is especially true when the capstan has a cone shape. There is a need for a tube lift system which is easy to operate and which will prevent the lift cords from becoming tangled when the blind is raised and lowered.
A second problem with tube lift systems arises from the fact that the diameter of the lift cords can vary by as much as five thousandths of an inch and the diameter of the tube or spool on which the lift cords are wrapped can vary by four thousandths of an inch. If a blind has two lift cords, each cord having a different diameter and each spool on which a lift cord is wound having a diameter different from the other spool, then it is possible that one lift cord will end up being longer than the other lift cord when the blind is lowered. This difference can be as much as one half to three fourths of an inch when the blind is fully lowered. Consequently, the bottomrail is noticeably slanted or uneven. Prior to the present invention the art had found no good solution to this problem. One solution was to shorten the cord which was longer when the blind was fully lowered so that the bottomrail appeared to be even when the blind was fully lowered. However, when that was done the bottomrail was slanted in an opposite direction when the blind was stacked. Another solution was to replace the lift cords. Depending upon how close the diameters of the replacement cords were to one another, this may or may not have been an improvement. Whatever the solution, the shade had to be disassembled and restrung. Consequently, there is a need for a cord lift system for blinds which can be adjusted to compensate for differences in diameters of lift cords and spools on which they are wound.
SUMMARY OF THE INVENTION
I provide a lift system for blinds of the type having at least one pair of lift cords for raising and lowering the blind. I prefer to provide a conical cord collector or cone for each center lift cord or each pair of lift cords that pass over the edge of the slats. I prefer that the cone be threaded. In an edge lift cord system two lift cords will lie side by side when wrapped around the cone. An axle passes through each externally threaded cone so that rotation of the axle will rotate the cones and the cones may slide along the axle or the axle will traverse the headrail. I prefer that the cones have a frusto-conical shape. I further prefer to provide a cover that surrounds at least a portion of each cone. This cover may be internally threaded. Optionally a drive wheel is positioned adjacent the cone which engages a lift cord as that lift cord is unwrapped from around the cone. The drive wheel is literally fixed relative to the headrail so that it is always adjacent where the lift cord enters the headrail space. At least one cone can be adjusted laterally and radially relative to the axle and the other cones so that the lift cord can effectively start wrapping on any diameter of the cone.
Other objects and advantages of the present invention will become apparent from a description of the present preferred embodiments shown in the drawings.
REFERENCES:
patent: 13251 (1855-07-01), Bixler
patent: 2250106 (1941-07-01), Lorentzen
patent: 2420301 (1947-05-01), Cusumano
patent: 3981343 (1976-09-01), De Vito
patent: 5133399 (1992-07-01), Hiller et al.
patent: 5178200 (1993-01-01), Hagen
patent: 5259433 (1993-11-01), Cloutier
patent: 5628356 (1997-05-01), Marocco
patent: 5699847 (1997-12-01), Villette et al.
patent: 6325131 (2001-12-01), Dekker et al.
Buchanan Ingersoll P.C.
Purol David M.
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