Patent Publication Number: US-6981539-B2

Title: Hardware and clutch mechanism for window treatment

Description:
RELATED APPLICATIONS 
     This Application claims priority to Provisional Application Ser. No. 60/456,974 filed Mar. 24, 2003 and incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention pertains to a support for shades, including cellular shades and other window treatments, and more particularly, to a mechanism with an improved and more effective head rail and clutch. 
     2. Background of the Invention 
     In recent years, a number of mono-control mechanisms were invented that allow lifting and lowering of cellular blinds. The early mechanisms were developed that utilized clutches and rotating lift, which required substantially more space than traditional cord, lock devices. The height and depth of these mechanisms usually exceeded 1 inch. Moreover, typically the drop length of the shade would determine the size of the spool in which lifting tape would be gathered. The longer the drop, the bigger the spool and head rail had to be. In other words, due to the complexity of the clutch mechanisms and the lift sets utilizing cords and tapes, larger head rails had to be developed to provide proper enclosure for these mechanisms. The size, and more particularly weight of the fabric of the shade were the major factors for the requirement of big clutch mechanisms. However, oversized head rail enclosures were objectionable because they detracted from the esthetical appearance of the shade. 
     Another disadvantage of the early mechanisms pertained to the structure of the pulley in the clutch. Typically the perimeter of the pulley was designed with series of rigid ramps with sharp edges forming a serpentine path receiving and engaging a cord trained around the perimeter. Sharper and more aggressive edges provided a solid engagement with the cord, thereby increasing the friction between the cord and the pulley and decreasing, or even eliminating slippage. By the same token, however, these sharp edges also tended to cut and fray the cord fibers and therefore reduce the useful life of the cord. 
     SUMMARY OF THE INVENTION 
     A window treatment support for holding and operating a window treatment, such as a shade, by selectively lowering and raising said shade, said support comprising a head rail with two opposed ends and receiving the window treatment; a clutch disposed at one end; an end cap disposed at the other end; and a shaft extending between said clutch and said end cap. The member is rotatable by said clutch and is arranged to receive an activating element from the window treatment to operate said window treatment. The clutch includes a pulley disposed co-axially with said shaft, said pulley including a plurality of teeth. At least some of the teeth have flexible projections. The teeth are arranged to receive a cord for operating said clutch. The flexible projections forming an interference fit with the cord. 
     Preferably, the pulley includes a cylindrical wall and each tooth includes a frame dependent from said cylindrical wall with said projection being suspended from said frame. The projections can be angled axially inwardly toward the opposite teeth and can have a free end and a substantially flat contact surface adjacent to the free end. 
     The pulley can include a first set teeth and a second set of teeth, said first and second sets being axially spaced along the cylindrical wall. The teeth form a serpentine channel for receiving said cord. 
     Preferably, the head rail includes a side wall and a bottom having two lateral portions and a center portion, the lateral side and said center portion extending longitudinally, and thee center portion being further spaced from a longitudinal axis of the head rail and than said side wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an isometric view of a shade support mechanism in accordance with this invention; 
         FIG. 2A  shows an exploded view of the shade support mechanism of  FIG. 1 ; 
         FIG. 2B  shows an elevational cross-sectional view of the support mechanism head rail in  FIG. 2A ; 
         FIG. 3A  shows an isometric view of a lift in the mechanism of  FIGS. 1 and 2 ; 
         FIG. 3B  shows a side view of the support mechanism with the lift shown in  FIG. 3A  in place; 
         FIG. 4A  shows an isometric view of the clutch and the clutch housing used in the shade support mechanism of  FIGS. 1 and 2A ; 
         FIG. 4B  shows an end view of the clutch mechanism and housing of  FIG. 4A ; 
         FIG. 5A  shows an isometric view of the pulley of  FIGS. 4A and 4B ; 
         FIG. 5B  shows an enlarged view of the pulley with details of the teeth used for the engagement of the cord. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in the Figures, a shade support  10  constructed in accordance with this invention, includes a head rail  12 , a clutch housing  14 , an end cap  16 , one or more lifts  18  and a shaft  20 . The support  10  is mounted in a window opening or on a wall (not shown) by brackets  22 . The brackets  22  are shaped so that they can engage either the front wall  24  or the back wall  26  of the head rail  12 . Front wall  24  has a somewhat curved profile while the back wall  26  is substantially straight. Thus, a customer can be given the option of mounting the support  10  so that either the front wall  24 , or the back wall  26  are facing inwardly. 
     The shaft  20  extends longitudinally through the head rail  12  and is supported by the clutch (discussed in more detail below) and the lifts  18 . A typical shade (not shown) has blades or cells that are supported by strings or other similar activating members (not shown) trained about the lifts  18 . A cord  28  with two ends (shown in  FIGS. 4A and 4B ) is trained around the clutch  15 . Pulling one end of the cord  28  causes the clutch to turn (as described in more detail below) in one direction and pulling the other end of the cord  28  causes the clutch to turn in the opposite direction. The rotation of the clutch is transmitted to the lifts  18  by the shaft  20 . Rotation in one direction causes the strings of the shade to wind up on the lifts  18  and to pull up or lift the shades. Rotation in the opposite direction causes the strings to wind down from the lifts  18  and allow the shades to lower. 
     Referring now to  FIGS. 2A and 2B , the head rail  12  is formed with a bottom wall  30  that extends substantially horizontally forms two trough shaped chambers: an upper chamber  32  and a lower chamber  34 . The upper chamber  32  holds the clutch  15 , lifts  18  and shaft  20 . The lower chamber is used for mounting the upper part of the shade (not shown). This shade can be cellular shade, a venitian blind or other type of window treatment. 
     The bottom wall  30  has a trapezoidal shape with a central portion  30 C and two lateral portions  30 A and  30 B angled upwards as shown. The central portion is disposed further from a longitudinal axis of the head rail  12  then the back wall  26 . Above the bottom wall  30  there are two facing lips  36 . These lips  36  engage and form a respective interference fit with the clutch housing  14 , the end cap  16  and the lifts  18  and hold these elements in place. As discussed above, it is important to provide the shade support mechanism with a large-sized clutch so that it can provide a large mechanical advantage for the raising of the shade. The dimension that has the biggest effect on the size of the clutch is the effective height H 1  of the upper chamber  32 . In previous shade support mechanisms, the bottom wall was planar and it was disposed at the position of the two lips  36 . Therefore the effective height of the upper chamber was much smaller, as indicated in  FIG. 2B  at H 2 . Hence the upper chamber  32  could accommodate a smaller clutch mechanism then the head rail  12  shown herein. In other words, the head rail  12  is able to accommodate a bigger clutch because of the shape and configuration of its bottom wall  30 . Of course, the bottom wall  30  could have different shapes as well and still achieve the same effect. For example, the bottom wall could be curved. 
     In  FIGS. 1 and 2A , only the clutch housing  14  is visible, with the actual clutch being hidden by a cover  38 . Details of the clutch  40  are shown in  FIGS. 4A ,  4 B,  5 A and  5 B. The clutch  40  includes a pulley  42  and a boss  44 . The pulley  42  has a peripheral cylindrical wall  46 . This wall  46  is formed with two sets of radial gripping teeth  48 ,  50 . Teeth  48  are placed axially inwardly of teeth  50  and define therebetween a serpentine-shaped annular channel  52  having dimensions that are approximately equal to the diameter of the cord  28 . 
     Each tooth  48 ,  50  is formed of two radial posts  53 ,  54  connected at their top by a cross piece  56 . The posts  53 ,  54  and cross piece  56  form a frame  58 . A projection  60  is suspended from the cross-piece  56  and extends radially inwardly therefrom. In addition, the projection  60  is also angled so that it extends between the teeth  48  and  50  to define at least part of the annular space  52  as shown. The projection  60  is somewhat flexible so that it can be deflected axially, i.e. toward or away from frame  58 . The projection  60  also has an engaging surface  64 . When the pulley  42  is introduced into the housing  14 , the housing and the serpentine channel form a torroidal space for the cord  28 . 
     As discussed above, in the prior art, pulleys for shade supports were provided with rigid ramps with sharp edges that cut into, and degraded the cord over time. In the present invention, as a cord  28  is introduced into the channel between the teeth  48 ,  50 , it pushes the projections  60  of teeth  48 ,  50  axially outwardly the respective frames  58 . Therefore, once the cord  28  is introduced between the teeth  48 ,  50 , an interference fit is formed between the projections  60  and the cord  20  that provides a gripping force on the cord and insures that there is no slippage as the cord  28  is pulled one way or the other. However the flexibility of the projections  60  and the shape and positioning of the engaging surface  64  insures that the fibers of the cord are not cut and therefore the cord is not damaged. 
     As shown in the  FIGS. 5A and 5B , preferably, the teeth of the set  48  are angularly offset from the teeth of set  50 . so that the projection on one tooth  48  is not opposite a projection on a tooth  50 . Moreover, the teeth of one set are offset from the teeth of the other set. This configuration forces the cord to take a serpentine path along channel  52 . 
     In an alternate embodiment of the invention, only some of the teeth have the flexible projections  60 . For example, all the teeth on one side may have the projection, or every second or every third tooth from both sets  48  and  50  is provided with a projection  60 . 
     While the invention has been described with reference to several particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles of the invention. Accordingly, the embodiments described in particular should be considered as exemplary, not limiting, with respect to the following claims.