Abstract:
A window treatment system for covering an architectural opening includes a window treatment with a sheet wound in a first direction; a housing having a longitudinal axis and receiving said window treatment; a shaft disposed coaxially within said housing for supporting said housing and a clutch coupling said housing and said shaft and having a first position in which said housing is rotatable with respect to said shaft only in one direction, and a second position in which said housing is rotatable in both directions. A spool is mounted coaxially with the longitudinal axis and is coupled to said clutch. The spool includes an elongated member such as a ribbon wound in a second direction and arranged to raise said window treatment when said elongated member is pulled from said spool.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. provisional application Ser. No. 60/845,319 filed on Sep. 18, 2006 and incorporated herein by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    a. Field of Invention 
         [0003]    This invention pertains to a window shade and other window treatment systems, and more particularly to a system in which a single cord is used to operate the shade. 
         [0004]    b. Description of the Prior Art 
         [0005]    A typical window treatment system consists of a mandrel attached to a window treatment, such as a window shade, a pulley receiving a cord used to operate the element, and a clutch coupling the pulley to the mandrel. The clutch may include a break mechanism arranged so that pulling the cord causes the window treatment to move up or down but the weight of the window treatment or a manual tug on the covering does not cause it to lower. 
         [0006]    A clutch for window treatment systems is disclosed in U.S. Pat. Nos. 5,791,393 and 5,927,370. The clutch includes a flat spring wound around a hub and having tangs at the ends. The tangs are arranged so that a rotation of the mandrel causes the spring to tighten around hub, thereby preventing the rotation of the window treatment. Rotation of the pulley causes the spring to loosen and allows the mandrel to rotate in one direction or another. In this arrangement, the cord has two ends disposed on either side of the pulley. Pulling on one end causes the window treatment to be raised and pulling on the other end causes the window treatment to be raised. 
         [0007]    However, in certain instances it is desirable to have a window treatment system that is operated by a single cord. In such a system, the window treatment is raised by pulling on a cord and is lowered by pulling on the window treatment itself. However, the clutch described above cannot be used for this system because it locks up when any force is applied to the window treatment. 
       SUMMARY OF THE INVENTION 
       [0008]    A window treatment system for covering an architectural opening constructed in accordance with this invention includes a window treatment including a sheet wound in a first direction; a housing having a longitudinal axis and receiving said window treatment; and a shaft disposed coaxially within said housing for supporting said housing. The system is further provided with a clutch coupling said housing and said shaft and having a first position in which said housing is rotatable with respect to said shaft only in one direction, and a second position in which said housing is rotatable in both directions with respect to the shaft. A spool is mounted coaxially with said longitudinal axis and coupled to said clutch. The spool includes an elongated member such as a cord or a ribbon wound in a second direction. The system is arranged so that when the clutch is in the first position, the window sheet can be raised by pulling on the elongated member. To lower the window sheet, the clutch is shifted or moved to the second position in which the housing is freely rotatable. The sheet can now be pulled down manually, either partially or all the way. 
         [0009]    In one embodiment of the invention, the clutch includes a coil spring disposed around said shaft and an actuator which, in the first position, winds said springs in a first configuration, and in the second position, winds the spring into a second configuration. The spool is preferably coupled to said actuator and cooperates therewith to pivot said actuator between said first and second positions as the elongated member is pulled by a user. 
         [0010]    Preferably, the spring has two tangs, one tang being engaged by said shaft and the second tang being engaged by said actuator. The housing includes a cylindrical surface and the spring selectively engages the cylindrical surface in the first position to form a friction fit and it disengages from said cylindrical surface in said second position. 
         [0011]    In one aspect of the invention, a mechanism for operating a window treatment including a mandrel and a sheet wound in a first direction on said mandrel is disclosed, the mechanism including a support shaft mounting the mandrel to an opening, the support shaft being fixed within the opening; a housing rotatably mounted on the support shaft; and a clutch interconnecting the support shaft and the housing selectively in one of a first configuration in which the housing is rotatable in both directions with respect to said shaft and a second configuration in which said housing rotates about the shaft in a single direction. An elongated member wound coaxially with the shaft is arranged to raise said the sheet when pulled. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows a partially exploded isometric view of a mechanism for supporting and operating a window treatment system in accordance with this invention; 
           [0013]      FIG. 2  shows a side view of the mechanism of  FIG. 1 ; 
           [0014]      FIG. 3  shows an end view of the mechanism of  FIG. 1 ; and 
           [0015]      FIG. 4  shows a center portion of the mechanism of  FIG. 1  with various adapters available as accessories. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    As shown in the  FIGS. 1-3 , a window treatment mechanism  10  constructed in accordance with this invention includes several components that fit together telescopically about a common longitudinal axis, including a housing  12 , a clutch  14 , an actuator  16  and a spool  18 . 
         [0017]    The housing  12  is tubular with a smooth inner cylindrical surface  20  and an outer surface  22 . Outer surface  22  has a plurality of longitudinal fins  24 . The purpose of fins  24  is to engage a mandrel  26  that support a window treatment  28 . One end of housing  12  has an enlarged head  30  formed with a plurality of radially running teeth  32 . 
         [0018]    The clutch  14  includes a hollow shaft  40 . One end of shaft  40  is formed with two axially extending fingers  42  (seen in  FIG. 4 ). The fingers  42  can be flexed inward toward the longitudinal axis of the shaft  40  and are sized and shaped to engage and trap the housing  12  when the housing  12  is in the operative position, as described more fully below and shown in  FIG. 4 . 
         [0019]    The opposite end of the shaft  40  terminates with a tubular boss  42  having an enlarged diameter and holding a flat torsion spring  44  with two end tangs (with only one tang  50  being visible) near the end of the shaft  40 . Tang  50  extends radially outward. The other tang extends radially inward and is received in a hole in the shaft  40  (not shown). Shaft  40  is provided at its opposite end with an annular rib  51 . 
         [0020]    Clutch  14  further includes a toroidal actuator  46 . Actuator  46  has an inner cylindrical surface  48  with an annular groove (not shown) sized and shaped to accept the annular rib  51 . Actuator  46  is also formed with one or more slots  60  on its outer surface. The actuator  46  is shaped to fit over the opposite end of the shaft  40 , as shown in  FIG. 1 , with the annular rib  51  disposed within the annular groove to capture the actuator  46 . Thus, the actuator  46  is attached to the shaft  40 , but can rotate with respect to this shaft. The angular motion of the actuator is limited, as discussed in more detail below. 
         [0021]    Shaft  40  of clutch  14  also includes a plurality of radial teeth  52 A,  52 B of said opposite end.  FIG. 1  shows a set of these teeth; however, two or more sets of teeth may be used as well. The actuator  46  has a disc-shaped body with at least two fingers  54 A,  54 B extending tangentially. (see  FIG. 3 ) These fingers  54 A,  54 B are visible through two windows  56 A,  56 B in the actuator  46  and have a slight radial extension (not shown). Fingers  54 A,  54 B are flexible in a radial direction, and their function is described in more detail below. Finally, the actuator  46  also has at least one slot  58  for receiving tang  50  of spring  44 . 
         [0022]    Once the actuator  46  of clutch  14  is assembled, the teeth  52 A,  52 B of shaft  40  are disposed between the fingers  54 A,  54 B. Fingers  54 A,  54 B are oriented toward each other, as seen in  FIG. 3 , and are arranged and shaped to limit the rotational movement of the actuator  46  with respect to shaft  40 . More particularly, in the position shown in  FIG. 3 , the actuator  46  can be rotated clockwise until the tooth  52 A comes into contact with the finger  54 A. Turning the actuator  46  further causes the finger  54 A to flex radially outwards by the caming action of the tooth  52 A against the radial extension  52 C. Once the tooth  52 A passes the tip of the finger  54 A, the finger  54 A snaps back, thereby engaging and trapping the tooth  52 A. In this configuration, the tooth  52 A and finger  52 A define a first position for the actuator  46  with respect to the shaft  40 . Tooth  52 B cooperates in a similar manner with the finger  54 B to define a second position for the actuator  46 . 
         [0023]    As previously mentioned, the tang  50  of spring  44  is received and engaged by slot  58  of the actuator  46 . Since the other end of the spring  44  is captured by the shaft  40 , the radial movement of the actuator  46  in the clockwise direction causes the spring  44  to wind tighter around the shaft  40 , and radial movement of the actuator  46  in the counterclockwise direction causes the spring  44  to unwind so that it is separated slightly from the shaft  40 . 
         [0024]    Because of the properties described herein, the elements of the mechanism  10  (except for the spring  44 ) are preferably made of a suitable plastic material by molding or other well known means. The spring  44  is preferably made of steel or other similar material and has a square or rectangular cross section to present a larger contact surface with the surface of the shaft  40  and the inner surface of the housing  12 . The diameter of housing  12  is chosen so that when the spring  44  is unwound, the spring  44  is in intimate contact with the inner surface of housing  12 . As a result of this arrangement, when the actuator  46  is in the first position, the shaft  40  of clutch  14  and the housing  12  are free to rotate with each other. When the actuator  46  is in the second position, the spring  44  is unwound sufficiently to come into contact with the inner surface of the housing  12 . As a result, the housing  12  is free to rotate with respect to the shaft  40  in the clockwise because this type of rotation tightens the spring  44  just enough so that the outer surface of the spring  44  separates from, or slides with respect to, the inner surface of the housing  12 . However, if the housing  12  is rotated in an opposite direction, the spring  44  expands and forms a frictional engagement with the inner surface of the housing  12 , thereby effectively locking the housing  12  and the shaft  40  together so that one cannot rotate without the other. 
         [0025]    Spool  18  is formed of two circular elements  70  and  84  (see  FIGS. 1 and 4 ) that cooperate to form a toroidal shaped space. The inner circular element  70  is formed with a ring-shaped base  74  and a tubular section  76  depending rearwardly from base  74 . Base  74  has a forward surface  72 . The tubular section  76  has an outer cylindrical surface  78  and an inner cylindrical surface  80  formed with a plurality of grooves  82 . The other circular element  84  includes a cylindrical outer wall  86  with a slot  88  (see  FIG. 3 ) and an outer ring-shaped wall  90  with two diametrically spaced prongs  92  extending axially therefrom. A ribbon  94  is wound around the surface  78  of member  84  and has a free end  94 A extending through the slot  88 , as seen in  FIG. 3 . 
         [0026]    Tubular section  76  of inner circular element  70 , is assembled with ribbon  94  wound thereon to define spool  18 . The spool  18  is attached to the housing  12  and the other elements inserted in the housing, with the teeth  32  of housing head  30  cooperatively engaging the grooves  82  of inner circular element  70 . The prongs  92  of circular element  84  snap into slot  60  formed along the outer surface of actuator  4  to form an interference fit between the spool and the actuator  46 . 
         [0027]    A window treatment  28  with mechanism  10  is assembled and installed as follows. The inner surface of the shaft  40  is provided with a plurality of radial ribs  96  (see  FIG. 3 ). When the mechanism  10  is installed in a window or door opening, a bracket section (not shown) supports the mechanism  10  and engages the ribs  96  to prevent the shaft  40  from rotating in either direction. The outer surface of the housing  12  with its ribs  22  along outer surface  22  are fit telescopically into the mandrel  26  and form a frictional engagement therewith so that they rotate together. The mandrel  26  supports a window treatment  28  including a sheet  29 . 
         [0028]    The mechanism  10  operates as follows. Initially, sheet  29  of window treatment  28  is wound all the way on the mandrel  26  and the actuator  46  is thus in its first position. The ribbon  94  is unwound from surface  78  of element  70  and its free end  94 A is hanging unwound along a side of the window opening. In this configuration, the window mechanism  10  is in its open position in order to allow light and air to come through the window opening. In order to close the window treatment  28 , the ribbon  94  is pivoted upward as at B (in  FIG. 3 ) by a user and pulled slightly to cause the actuator  46  to pivot from its first to its second position. With the actuator  46  in the second position, the housing  12  is free to rotate in either direction with respect to the shaft  40 . The user can now grab the end of the sheet  27  of treatment  28  downward, either all the way until the window treatment is closed, or to any intermediate position. As the sheet  29  of window treatment  28  is unwound from the mandrel  26 , the housing  12  turns counterclockwise and the ribbon  94  is wound up into spool  18 . When the desired position of the window treatment is reached, the user pulls on the ribbon  94  slightly downward, causing the actuator  46  to pivot back to its first position. In this position, the housing  12  is allowed to rotate clockwise but not counter clockwise and therefore the window treatment is blocked from being unwound any further. In this configuration, pulling the ribbon  94  causes the housing  12  to rotate clockwise to wind the sheet  29  into the mandrel  26 . 
         [0029]    The mechanism  10  can be modular to accommodate several different types of window treatments and several different types of window/door openings. For this purpose, as shown in  FIG. 4 , the mechanism  10  can be distributed with one or more mandrels  26 A,  26 B having different diameters, as well additional bracket adapters  98 A,  98 B that fit into shaft  40  as shown. 
         [0030]    Numerous modifications may be made to this invention without departing from its scope, as defined in the appended claims.