Self-raising window covering
The present invention relates to a self-raising window covering and a control mechanism for the window covering. In particular, the window covering includes a drive unit, such as constant force spring, that is adapted to apply a substantially constant rotational force on the drive axle. A cord winding assembly is coaxially mounted on the drive axle, and includes at least one winding drum operatively connected to a second end of the raising cord and having a tapered portion, as well as a rotatable positioning member for moving the cord winding assembly laterally along the drive axle upon rotation of the positioning member. The cord winding assembly is adapted to translate the rotational force on the drive axle to a raising force on the raising cord, wherein the raising force is greater than a downward force exerted by the shade element and bottom rail throughout the range of opening and closing. A clutch member or locking member is also operatively connected with the axle and adapted to releasably lock the drive axle in a desired position.
This application is a continuation application of U.S. patent application Ser. No. 11/880,000, filed on Jul. 19, 2007, which is incorporated herein by reference.
FIELD OF INVENTIONThe present invention relates to a window covering that may be raised without the need to apply a force to either a control mechanism or the window covering itself as the window covering is opened. In particular, the present invention relates to a window covering having a control mechanism configured to exert an upward force on the light blocking element and bottom element that is of sufficient magnitude to raise the light blocking element and bottom rail without additional force being applied by the user during raising. The control mechanism selectively raises the window bottom element and portions of the window covering, and may be actuated by a downward force applied to the bottom element by the user.
BACKGROUND OF THE INVENTIONWindow shades and coverings are found in many applications and used to regulate the amount of light entering a room, and to provide aesthetic appeal to a decor. Such window shades and coverings take many forms, including roller shades, Roman shades, Venetian blinds, and cellular shades. Conventional cellular or pleated shades utilize cord locks or a transmission mechanism to raise, lower and position the window covering in a desired position. With window coverings utilizing a cord lock, cords run up through the folded fabric, across the inside of a head rail and exit through a locking mechanism. Other cellular shades include a transmission mechanism and a continuous loop cord that is pulled by a user to raise and lower the window shade. Roman shades and Venetian blinds also tend to include raising cords that are secured to a lower bar or bottom rail.
There are some disadvantages to these designs. Cords present the potential hazard of a child getting caught in or strangled by the exposed control cord. Cords also tend to distract from the aesthetics of a window covering in that they extend along the face of the window covering and, when the window shade is opened, must either be wrapped on a hook or just left on the floor. With window coverings that utilize cord locks, the cords also experience substantial wear due to friction against surfaces as a result of raising and lowering of the window covering.
Other window coverings include common roller shades, which operate in the absence of a cord. These roller shades include a wound torsion-spring retraction mechanism in combination with a clutch or locking mechanism mounted with a roller onto which the shade is rolled and collected. In operation, a roller shade is pulled down by a user to a desired location, where it is locked in place by the clutch or locking mechanism. To unlock and release the shade so that it may be raised, the user typically pulls on a bottom rail of the shade, extending the shade sufficiently to disengage the internal clutch or locking mechanism within. When the clutch or locking mechanism is disengaged and the user releases the shade, the shade is retracted using the torsion-spring driven retraction mechanism. Known roller shades, however, are only operable with flat shade material which rolls up neatly into a confined location.
The mechanism utilized in such roller shades is not compatible with other window coverings, such as cellular shades, Venetian blinds, and Roman shades. As roller shades are raised, the amount of shade being lifted decreases such that a constant force torsional spring member is capable of applying the necessary winding or upward force throughout the opening range. By contrast, a similar lifting mechanism is typically unsuitable in cellular shades, Venetian blinds, and Roman shades. In these types of window coverings the light blocking material is typically gathered by raising a bottom member, such as a bottom rail, and increasing amounts of weight are gathered on the bottom member as the window covering is raised. The reason for this is that the shade material or light blocking element increasingly stacks on the bottom rail as the bottom rail rises, which increases the load on the lifting mechanism.
In order to address this increasing weight, very strong torsional springs have been used to accommodate the maximum weight of the shade. One drawback to this approach, however, is that the rate at which the window covering is retracted may be too fast and uncontrolled. One attempt to address this problem is found in U.S. Pat. No. 6,666,252, issued to Welfonder. This patent teaches the use of a fluid brake to control the rate at which the raising cords are retracted throughout the raising process. Another approach that has been used is shown in U.S. Pat. No. 6,056,036, issued to Todd, which employs a mechanical friction member to continuously slow the rate of retraction. One problem with these approaches has been that the spring utilized exerts a force that is difficult for a user to overcome when attempting to lower the shade. Excessive pulling force by the user often results in damage to the window covering.
Alternatively, variable force springs have been used. Such variable force springs are substantially more complicated in use and manufacture.
Therefore, there is a need for a window covering raising mechanism for window coverings such as Venetian blinds, cellular shades and Roman shades that is self-raising and overcomes the foregoing problems.
SUMMARY OF THE INVENTIONThe present invention relates to a self-raising window covering and a control mechanism for the window covering. In particular, the window covering is a self-raising window covering that includes a head rail, a light blocking element, such as a cellular panel, blind slats, or Roman shade material, a bottom rail or bottom element, at least one raising cord operatively connected at a first end to the bottom rail or bottom element, and a control mechanism. The head rail may define an elongated channel wherein the control mechanism is disposed therein. In some embodiments, the control mechanism includes a drive shaft and a drive unit operatively connected with the drive shaft. The drive unit, which may be a constant force spring, is adapted to provide a substantially constant rotational force on the drive shaft.
At least one translation member is also provided in co-axial relation with the drive shaft. Typically, the number of translation members will be the same as the number of raising cords. However, in some instances, the translation member may be adapted to raised multiple cords. The translation member preferably includes at least one winding drum operatively connected to a second end of the raising cord and having a tapered portion. The translation member also includes a rotatable positioning member for moving the translation member laterally along the drive shaft upon rotation of the positioning member. In a preferred embodiment, the positioning member is a threaded tubular member connected to the winding drum. The translation member is adapted to translate the rotational force on the drive shaft to a raising force on the raising cord, wherein the raising force is greater than a downward force exerted by the light blocking element and bottom rail throughout the range of opening and closing. In a preferred embodiment, the translation member is rotationally secured with the drive shaft by a hub member adapted to engage the translation member and the drive shaft. The hub member may be in a sliding relationship with the tapered portion of the translation member.
A clutch or locking or actuating member is also operatively connected with the axle and adapted to releasably lock the drive shaft in a desired position. In a preferred embodiment, the clutch or locking or actuating member comprises a spring member adapted to releasably secure the position of the drive shaft when in a tightened condition and to permit rotation of the drive shaft when in a relaxed condition. A reciprocator may also be disposed annularly about the drive shaft and adapted to selectively hold the spring member in the tightened and relaxed positions. An annular collar may also be secured with the drive shaft and connected with the spring member. In some embodiments, it may also be desired to include a brake unit engageable with the translation member.
The invention disclosed herein is susceptible to embodiment in many different forms. Shown in the drawings and described in detail hereinbelow are preferred embodiments of the present invention. The present disclosure, however, is only an exemplification of the principles and features of the invention, and does not limit the invention to the illustrated embodiments.
Referring to
Referring to
For example, a spring unit 114 is shown in
Referring again to
Translation member 20 is mounted co-axially with the drive shaft (not shown), and includes a winding drum 24 and a rotational positioning member, such as threaded tubular member 32. The translation member 20 is preferably mounted to the drive axle by way of a hub member, such as adapter 60. The winding drum 24 may be tapered and is preferably frustoconical in shape, and may include striations or grooves. An end of the raising cord (not shown) is secured towards the larger diameter end 62 of the winding drum 24 such that as the cord is wound, the raising cord is wrapped around increasingly narrower portions of the winding drum 24. The translation member is mounted within the head rail 12 (
Referring to
As the spring units 14 and 16 raise the bottom rail 40 and stack the light blocking element 38 on the bottom rail 40, the total weight being raised increases. The load of the springs is described with reference to one of the spring units. The load of the spring unit 14 can be approximated as the force F relative to the drive axle as being equal to the product of the suspended weight W, which includes the weight of the bottom rail plus the amount of panel stacked thereon, by a winding radius R of the winding drum 24. As the bottom rail rises, W increases while R decreases. Because of the tapered winding drum 24, the force of the spring unit 14 translated to an upward force on the raising cord 28 will vary slightly so that the constant force spring 46 (
As discussed, the drive units are configured to provide a force sufficient to raise the bottom rail 40 and light blocking element 38 regardless of the current position of the window covering. Accordingly, a clutch member or actuator 36 is also provided in order to lock the window covering in a desired position. Clutch member 36 is mounted with the drive axle 18 and is configured to unlock the drive axle 18 as the user pulls down the bottom rail 40, and to lock the drive axle 18 when the user releases the bottom rail 40 at the desired height. When the user pulls down slightly on the bottom rail again, the clutch disengages and allows the bottom rail 40 to be raised by the spring units 14 and 16. Referring to
An alternative embodiment of the window covering according to the present invention is shown in
The preferred embodiment of the deceleration member 520 is shown in
The foregoing descriptions are to be taken as illustrative, but not limiting. Still other variants within the spirit and scope of the present invention will readily present themselves to those skilled in the art.
Claims
1. A window covering comprising:
- a head rail;
- a shade element including a top end and a bottom end, wherein the top end is secured with the head rail, and the shade element is vertically suspended from the head rail and suspended at a stationary first position;
- a bottom element secured with the bottom end of the shade element;
- a raising member connecting a control mechanism and the bottom element;
- the control mechanism including a drive unit that exerts a raising force in a first direction, the raising force being selectively communicated to the raising member and is sufficient to raise the bottom element from the first position to a second position and to stack increasing portions of the shade element on the bottom element, the control mechanism further including an actuator having a locked condition and a release condition such that when in the locked condition the actuator counteracts application of the raising force on the raising member, and when the actuator is in the release condition the raising force is communicated to the raising member to raise the bottom element; and
- the actuator is moved from the locked condition to the release condition by communication of a second force to the drive unit, the second force being opposite in direction to the raising force in the first direction.
2. The window covering of claim 1, wherein the bottom element is stationary in the first position and the actuator is in the locked condition.
3. The window covering of claim 1, wherein the bottom element is movable from a position vertically higher than the first position to the first position by a downward force on the bottom element, wherein after release of the downward force the actuator switch member is in the locked position.
4. The window covering of claim 1, wherein:
- the raising member is a cord element having a distal end connected with the bottom element;
- the control mechanism further comprises a cord winding assembly configured to wind and unwind the cord element;
- the drive unit continuously applies a spring force for rotating the cord winding assembly in the first direction that winds the cord element; and
- the actuator is a clutch operable to selectively lock rotation of the cord winding assembly.
5. The window covering of claim 4, wherein the clutch member permits rotation of the cord winding assembly in a direction for unwinding the cord element when a downward force is applied on the bottom element.
6. The window covering of claim 4, wherein the drive unit continuously applies the spring force on a drive axle coupled with the clutch member and the cord winding assembly.
7. The window covering of claim 6, wherein the clutch member selectively locks rotation of the drive axle against the spring force of the drive spring unit.
8. The window covering of claim 1, wherein the shade element includes a collapsible structure.
9. A window covering comprising:
- a head rail;
- a shade element vertically suspended from the head rail;
- a bottom element secured with a bottom end of the shade element, the bottom element being suspended from the head rail at a first position; and
- a control mechanism operatively connected to the bottom element by a raising member, wherein the control member selectively retracts the raising member and raises the bottom element from a first position to a second position in response to a downward displacement of the bottom element from the first position sufficient to disengage an actuator, and wherein increasing portions of the shade element are stacked on the bottom element as the bottom element is raised.
10. The window covering of claim 9, wherein the raising member is a cord, and wherein the control mechanism comprises:
- a spring unit;
- a cord winding assembly coupled with the bottom element via the cord; and
- the actuator is a clutch member configured to block rotation of the cord winding assembly when the bottom element is in the first position, and enable rotation of the cord winding assembly in response to the downward displacement of the bottom element from the first position.
11. The window covering of claim 10, wherein the spring unit continuously applies a spring force to rotate the cord winding assembly in a first direction that winds the cord element.
12. The window covering of claim 10, wherein the clutch member permits rotation of the cord winding assembly in a second direction for unwinding the cord element when a downward pulling force is applied on the bottom element.
13. The window covering of claim 10, wherein the clutch member and the cord winding assembly are coupled with a drive axle.
14. The window covering of claim 13, wherein the spring unit applies the spring force on the drive axle.
15. The window covering of claim 14, wherein the clutch member selectively blocks rotation of the drive axle against the spring force.
16. The window covering of claim 9, wherein the shade element includes a collapsible structure.
17. A method of operating a window covering, wherein the window covering comprises a shade element vertically suspended from a head rail, a bottom element secured with a bottom end of the shade element, and a control mechanism adapted to apply a spring force in a first direction to selectively raise the bottom element and to stack increasing portions of the shade element on the bottom element, the method comprising:
- applying a downward force on the bottom element and moving the bottom element from a stationary first position to a release position lower than the first position such that the downward force is communicated to the control mechanism and acts in an opposite direction to the spring force in the first direction; and
- discontinuing application of the downward force on the bottom element when the bottom element is at the release position; and
- permitting the spring force of the control mechanism to raise the bottom element free of a user applied upward force on the bottom element and such that at least a portion of the shade element is stacked on the bottom element.
18. The method of claim 17, wherein the shade element includes a collapsible structure.
19. The method of claim 17, further comprising applying a downward force on the bottom element after permitting the spring force of the control mechanism to raise the bottom element and causing the control mechanism to block further raising of the bottom element.
Type: Application
Filed: Apr 13, 2009
Publication Date: Oct 15, 2009
Inventors: Fu-Lai Yu (Taipei Hsieh), Chin-Tien Huang (Taipei Hsieh)
Application Number: 12/386,016
International Classification: A47H 5/00 (20060101);