Patent Publication Number: US-2019178030-A1

Title: Window covering system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to U.S. provisional application Ser. No. 62/335,337 filed May 12, 2016, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to window treatments. Particular embodiments relate to a mechanism that includes a short cord to control movement of a window dressing. 
     BACKGROUND OF THE INVENTION 
     Generally, window treatment systems for covering windows and/or for decorative purposes that can be used, for example, by residential, commercial, and industrial consumers are known. Some examples of these systems include window blinds, venetian blinds, roman shades, and vertical blinds. A typical system for covering a window can include a window covering element, a mechanism for raising, lowering, or otherwise opening or closing the window covering element and one or more cords configured to control the mechanism. 
     The cord may be, for example, a string, a rope, or a continuous chain (e.g., comprised of plastic or metal beads). Commonly, cords that are included in window treatment systems form a closed loop that may be openly accessible, for example, to children and pets and may cause injuries if used incorrectly. 
     To address this problem, various systems have been developed. For example, electronic systems have been designed that eliminate the need for a cord. However, such electronic systems are expensive and can be complicated to control. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to a system configured to control the raising and lowering and/or opening and closing of a window covering reliably and easily using a very short length cord positioned out of reach of a child, a pet or the like in order to eliminate potential danger to them. 
     In an embodiment, the present disclosure is directed to a window treatment system that includes an elongated tube around which a window covering can be wound, a clutch assembly including a pulley and a power spring having a first end engaging the pulley and a second end that is stationary, a booster assembly, a cord arranged at least partially within the clutch assembly, and a wand fixed to the cord to selectively raise and lower the window covering. 
     In an embodiment, the clutch assembly includes a guard that, in an assembled state, with the pulley forms at least one cavity and in the cavity the cord and the power spring are arranged. 
     In an embodiment, the guard includes at least one opening, and the clutch assembly further includes an eyelet disposed within the opening and the cord is configured to extend through the eyelet and the opening. 
     In an embodiment, the eyelet is made of a smooth, highly polished material such as ceramic to reduce friction between the eyelet and the cord as the cord moves between an extended position and a retracted position. 
     In an embodiment, the cavity between the guard and the pulley defines a path for movement of the cord between a retracted position and an extended position through the eyelet, the path being sized and shaped to reduce wear on the cord during movement thereof. 
     In an embodiment, the guard and the pulley define a path of movement for the cord through the eyelet that is angled to reduce wear on the cord. 
     In an embodiment, the eyelet is angled within the opening of the guard so that the eyelet is positioned in an orientation selected to reduce wear on the cord. 
     In an embodiment, the guard has a bottom wall that includes a first opening and a second opening, and the clutch assembly further includes a first eyelet disposed in the first opening and a second eyelet disposed in the second opening with the cord extending through the first eyelet when the window covering system is configured for right-handed operation and the cord extending through the second eyelet when the window covering system is configured for left-handed operation. Alternatively, one of the eyelets can be replaced by a blanking plug. 
     In an embodiment, the booster assembly includes a main pre-tensioned spring configured to provide a force for movement of the window covering between a retracted position and an extended position. The clutch assembly may include an aperture at an outer end, to provide access to a tensioning component engaged with the main spring, such that the tension of the main spring may be adjusted by adjusting a position of the tensioning component. 
     In an embodiment, the system may include a limiter assembly. The limiter assembly may be configured to be set at least a first position for the window covering that represents a fully retracted position of the window covering. 
     In an embodiment, the limiter assembly further comprises a stop to prevent the window covering from further raising once it reaches a predetermined upper position. 
     In an embodiment, the limiter assembly further comprises further comprising a wheel coupled to and rotatable with the window covering, wherein the stop is a threaded screw with a stop and the wheel travels axially along the screw as the screw is rotated until the travelling wheel reaches and abuts the stop when the window covering reaches a predetermined upper position. 
     In an embodiment, the limiter assembly further comprises an engaging means to manually define the predetermined upper position. 
     In an embodiment, wherein the engaging means is a thumb wheel coupled to the threaded screw for manually defining the predetermined upper position by selectively turning the screw. 
     In an embodiment, the present disclosure is directed to a limiter assembly that may include a retractable pin to engage a mounting bracket. The retractable pin may be biased outwardly, such that when installing the blind, the pin can be compressed inward to allow the installer to position the limiter assembly with respect to the mounting bracket. When released, the biasing force forces the pin outward to engage the mounting bracket and secure the window treatment system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of an embodiment of a window treatment system incorporating the present invention; 
         FIG. 2  shows an exploded view of the window treatment system of  FIG. 1 ; 
         FIG. 3  shows an exploded view of a clutch assembly of the window treatment system of  FIG. 1 ; 
         FIGS. 4-12  show details of components of the clutch assembly; 
         FIG. 13  shows an assembly view of the clutch assembly; 
         FIG. 14  shows a perspective view of the clutch assembly; 
         FIG. 15  shows an exploded view of a booster assembly of the window treatment system of  FIG. 1 ; 
         FIG. 16  shows a perspective view of the booster assembly; 
         FIGS. 17-22  show details of components of the booster assembly; 
         FIG. 23  shows an exploded view of a limiter assembly of the window treatment system of  FIG. 1 ; 
         FIG. 24  shows partially exploded views of the limiter assembly; 
         FIGS. 25A-32  show details of the components of the limiter assembly; 
         FIG. 33  is a perspective view of the limiter assembly; 
         FIG. 34  shows an exploded view of a wand of the window treatment system of  FIG. 1 ; 
         FIGS. 35-38  show details of components of the wand. 
         FIG. 39  show a device used to pretension a spring of the booster assembly; and 
         FIGS. 40A-40B  show details of another embodiment of a clutch assembly that includes a cord guard assembly. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     With reference now to the drawings, embodiments of a window treatment system of the present disclosure, which is generally designated by the reference numeral  10 , will be described. It should be noted that these drawings have been drawn to scale and as such show the relative sizes of the window covering system  10 . 
     Referring first to  FIG. 1 , the window covering system  10  includes a tube  12  with a window covering  14 , such as a window shade, that is wrapped around the tube  12  in a conventional manner. The system  10  is delimited and supported by a first end bracket  16  and a second end bracket  18  between an opening, such as a window or a doorway (not shown). 
     As shown in  FIG. 2 , the window covering system  10  further includes a clutch assembly  100 , a booster assembly  200  and a limiter assembly  300 . These assemblies  100 ,  200 ,  300  are sized so that, except for components at the ends of the clutch and limiter assemblies  100 ,  300 , the assemblies  100 ,  200 ,  300  can be arranged within the tube  12  and hidden from view. 
     A wand  20  is disposed near the first end bracket  16  and attached to a cord  22  to aid in selectively moving the cord  22  between a retracted position and an extended position. By moving the cord  22  between a retracted position and an extended position, the window covering  14  can be selectively lowered or raised to a desired height between a fully extended position dictated by the overall length of the window covering  14  and a fully retracted position, which is set during installation of the window covering system  10  by the limiter assembly  300 . At any given time, the window covering  14  is locked at the preselected height by the booster assembly  200  and the window covering  14  does not go up or down except under the control of an operator. 
       FIG. 1  shows the window covering  14  at three positions: HU, H 0  and H 1 . There are two ways to raise or lower the shade. For example, the window covering  14  can be lowered from a first position H 0  to a second position H 1  (see  FIG. 1 ) by grabbing the wand  20  and pulling the wand  20  downward repeatedly, until the window covering  14  reaches the second position H 1 . The cord  22  is spring loaded (as described below). As the wand  20  is pulled downwardly, the wand  20  pulls at least a portion of the cord  22  out of the clutch assembly  100  causing the booster assembly  200  and tube  12  to rotate and allow movement of the window covering  14 . Simultaneously, a coil spring  216  arranged within the booster assembly  200  is tightened as well. Once a desired position of the window covering  14  is reached, the force on the wand  20  (and cord  22 ) is released. The cord  22  and the wand  20  are pulled upwardly toward the clutch assembly  100  until the end of the wand  20  fixed to the end of the cord  22  contacts the clutch assembly  100  such that the clutch assembly  100  acts as a stop for the movement of the cord  22  and wand  20 . Because the cord  22  is relatively short, preferably the operator can pull on the wand  20  repeatedly until the window treatment is lowered to the desired position. Each time a downward force on the wand  20  is released, the booster assembly  200  automatically locks the tube  12  and shade  14  in place. 
     To raise the window covering  14  from an extended position, the wand  20  can be pulled downwardly slightly and then released, causing the cord  22  and the clutch assembly  100  to release the window covering  14 . A main coil spring  216  of the booster assembly  200  applies a rotational force on the tube  12  causing the tube  12  to rotate and in turn raise the window covering. Damping forces are applied within the booster assembly  200  to ensure that the upward motion of the window dressing  14  is a controlled, relatively slow and linear in motion. As such, the booster assembly  200  performs two functions: (1) it provides a force necessary to raise the window covering  14  and (2) it acts as a speed governor by controlling the speed at which the window covering  14  rises when released from a resting state. It is noted that if no action is taken by an operator when the window covering  14  is being raised toward an upper limit HU, the window covering  14  will continue to rise until it reaches the upper limit HU as set and defined by the limiter assembly  300 . 
     Alternatively, instead of using the wand  20 , an operator can grab a lower end  14 A of the window dressing  14  and manually pull the window covering  14  from the first position H 0  to the second position H 1 . When the window covering  14  is manually raised and/or lowered by pulling directly on the window dressing  14 , the cord  22  is disassociated from the booster assembly  200  by the clutch assembly  100  and remains in place together with the wand  20 , as explained below. 
     To manually raise the window covering  14 , an operator can pull downwardly slightly and then release the lower end  14 A of the window covering  14 , causing the booster assembly  200  to be unlocked and thereby allowing the booster assembly  200  to cause rotation of the tube  12 , and in turn, raise the window covering  14  toward the upper position HU. 
     As shown in  FIG. 3 , the clutch assembly  100  includes: a self-locking ring  101 ; a cord guard  102  with a boss  104 ; a washer  105 ; a concentric power spring  106 ; a pulley  108 ; an eyelet  108 A; a cord guard cover  110 ; a clutch sleeve  112 ; a cam drive dog  114 ; a clutch spring  116 ; a clutch spring bushing  118 ; a compression spring  120 ; a compression spring retainer  122 ; a crown  124 ; a clutch cover  126 ; two clutch springs  128 ; an adjusting shaft  130 ; a clutch inner member  132 ; a self-locking ring  134 ; and a connector drive  136 . Optionally, the clutch assembly  100  may also include a blanking plug  108 B. A similar clutch is described in more detail in International Application No. PCT/AU2016/00053, the contents of which are incorporated herein by reference, with the difference being that the embodiment of the present clutch is adapted for use with a cord and wand rather than a looped cord as described in International Application No. PCT/AU2016/000053. 
       FIGS. 4-12  show details of the components comprising a clutch assembly  100  and how these components interact with each other to provide the described functions. As can be seen in  FIG. 14 , in an assembled state, the clutch assembly  100  is compact, requiring little space. The pulley  108  and guard  102  form a first cavity  102 X (See  FIG. 13 ) therebetween in order to house cord  22  (when it is wound) and a second cavity  102 Y for holding power spring  106 . 
     As also shown in  FIG. 11A , guard  102  has an opening  108 X in which an eyelet  108 A (shown in  FIG. 9 ) can be arranged through which the cord  22  can extend in order to prolong the life of the cord  22  by preventing the cord  22  from being damaged (e.g., frayed, cut, etc.). In an embodiment, the eyelet  108 A is made of a long-lasting, low friction material such as ceramic or a similar material. As described below, the cord  22  is reciprocated up and down through the eyelet  108 A and may be frequently at an angle such that the cord  22  rubs against an inner surface of the eyelet  108 A. The eyelet is made of a low-friction material to prolong the life of the cord.  FIG. 11  illustrates an embodiment with a single eyelet  108 A.  FIGS. 40A-B  show another embodiment with eyelets  108 A disposed in respective holes  404 ,  406 . This embodiment is described in more detail below. As discussed above, the system  100  can be configured for right-handed or left-handed operation. 
     Details of the pulley  108  are shown in  FIGS. 6-7 . As can be seen, the pulley  108  includes a first opening  108 XX and a second opening  108 YY with one opening being used for the left-handed operation and the other being used for the right-handed operation. The cord  22  is wound on the outer perimeter of the pulley  108  and is terminated with a knot (not shown). The knot is configured to fit into either of the first opening  108 XX or the second opening  108 YY. The guard  102  is shown in  FIG. 11B  and it not only protects the elements of the clutch mechanism but also forms a smooth path for the cord  22  from one of the openings  108 XX,  108 YY to eyelet  108 A. 
     As mentioned above, as the cord  22  is pulled down by wand  20 , the cord  22  causes the pulley  108  to turn. This rotation of the pulley also tightens power spring  106 . 
     Importantly, as shown in  FIG. 4 , the power spring  106  is narrow. It is made of a high quality type 301 steel. In one embodiment, it has a thickness of about 0.011 in, a width of about 0.080 in and a length of about 80.5 inches. It can generate a torque of about 0.60 lbf.in. 
     The power spring  106  is terminated in two respective U-shaped tabs  106   a  and  106   b . Each tab is about 0.150 in length and has a radius of curvature of about 0.025 in. As shown in  FIG. 7 , pulley  108  is formed with a curved circumferential slot  108 Z accessible through a radial channel  108 ZZ. As can be seen from  FIG. 7 , the slot  108 Z extends on either size of channel  108 ZZ. The channel  108 ZZ and slot  108 Z are sized and shaped to receive tab  106   b  of power spring  106  with the power spring  106  being wound either clockwise or counterclockwise, depending on whether a right-handed or left-handed operation is used. The pulley  108  is shaped to form a circular housing for the power spring  106 , thereby insuring the overall axial dimension of the clutch is as small as possible. 
     The other tab  106   a  of power spring  106  fits into slot  410  formed on the internal surface of guard  102 , as shown in  FIG. 11B . 
     When the wand  20  is pulled down, the pulley  108  is turned by cord  22  and the clutch mechanism is engaged. Since the guard  102  is stationary, as the pulley  108  is rotated by cord  22 , it winds the power spring  106  as cord  22  is pulled down. Once the downward force on the wand  20  is removed, the clutch mechanism is disengaged and the wound power spring  106  rotates the pulley  108  in the opposite direction thereby pulling the cord  22  up and winding it on the pulley  108  until the end of wand  20  proximal to the cord guard  102  comes in contact with the clutch assembly, which acts as a stop. 
     As shown in  FIG. 15 , the booster assembly  200  includes: a booster outer sleeve  202 ; a barrel cam tube adapter  204 ; a position stop track member  206  with a plurality of tracks  208 ; a ball bearing  210  running in tracks  208  on the stop track member  206 ; a position stop jacket  212 ; a shaft  214  shorter than sleeve  202 ; a booster spring  216 ; a free head  218 ; a booster idler tube adaptor  220 ; a booster/decelerator adapter  222 ; a brake or damper  224 ; and a decelerator adapter  226 . 
       FIG. 16  shows how many of the components of the booster assembly  200  are assembled to each other and fit into the booster outer sleeve  202 . It should be noted that most of the components are arranged in the same manner whether the cord  22  is disposed on the right or the left side of the system  10 . However, the position of the booster/decelerator adapter  222 , the brake or damper  224  and the decelerator adapter  226  are reversed when the cord  22  is on the right side of the system  10  and some minor changes to assembly configurations may be needed as well without departing from the overall invention. 
       FIGS. 17-22  show details of the components of the booster assembly  200 . 
       FIGS. 23 and 24  show exploded views of the limiter assembly  300 . The limiter assembly includes the following components: a bracket cover  302 ; a keyed end bracket  304 ; a retractable pin  306 ; a compression spring  308 ; a spring disk  310 ; limiter wheel springs  312 ; a thumb wheel  314 ; a housing  316 ; spring pins  318 ; a limiter screw  320 ; a limiter stop wheel  322 ; a stop boss  324 ; an idler wheel  326 ; and an adjustment wheel sleeve  328 . The keyed end bracket  304  can be secured to an end of the window covering  14 . 
       FIGS. 25 to 32  show details of the components of the limited assembly  300 .  FIG. 33  illustrates the limiter assembly  300  in an assembled state. 
     The wand  20  is shown in further detail in  FIGS. 34 to 38 . The wand  20  engages and encloses the end of cord  22 . As shown in  FIG. 34 , the wand  20  includes top cap inner  23 , top cap  24 , wand body  25  and bottom cap  26 .  FIGS. 35 to 38  show details of the components of wand  20 . 
     In the embodiment illustrated at  FIGS. 34 to 38 , the end of cord  22  passes through top cap inner  23  where it can, for example, terminate with a knot or other means. The inner cap  23  can be fixed within top cap  24 , which is then itself fixed to wand body  25 , to ensure that the cord  22  cannot be separated from the wand  20 . In the illustrated embodiment, the top cap  24  is fixed to the wand body  25  by engaging means on each piece. The wand may also include bottom cap  26 , which is an aesthetic cap attached to the end of the wand body  25  distal to the cord  22 . 
     Importantly, at a proximal end of the wand  20 , the cord  22  passes through the wand  20  and immediately enters the clutch assembly  100  through an eyelet  108 A ( FIG. 3 ) mounted on a bottom surface of the clutch assembly  100 . The cord  22  is wound around the pulley  108 . The spring  106  and pulley  108  are arranged to pull the cord  22  into the clutch assembly whenever it is released (as discussed below) so that the wand  20  virtually abuts the clutch assembly and the cord  22  is almost invisible ( FIG. 14 ). In this way, the device ensures that the cord  22  is not normally exposed to cause possible injury to a child. 
       FIG. 39  shows details of a tool  500  used to pre-tension the spring  216  of the booster assembly  200 . Initially, the spring  216  is pre-tensioned using the tool  500  at the factory. In addition, the clutch assembly  100  features an adjustment shaft  130  that engages the tool  500  and the clutch inner member  132  to the pre-tension spring  216 . Turning the tool in one direction causes the spring  216  to be tightened. Turning the tool  500  in the opposite direction loosens the spring  216 . 
     At the site, the device including the shade rolled up on tube  12  ( FIG. 1 ) is unpacked and prepped for installation, for example, on a wall, a window frame, etc. As part of this process, the limiter assembly is adjusted to set the desired upper position of the window shade (as described below). This is the position at which the window shade moves when it is released from any lower position. 
     Once the system  10  is installed, it can be readily used to lower or raise the window covering  14  as desired either, manually or using the wand  20 . For the purposes of the discussion below, it is assumed that initially the window covering  14  is in its upper position. As the wand  20  pulls on the cord  22  for a short distance (e.g. about ¼ inch), the window covering  14  does not move. The reason for this is that within the clutch assembly  100 , the compression spring  120  ( FIG. 3 ) pushes the clutch sleeve  112  and the cam drive dog  114  towards the right and into the core guard cover  110  and clutch pulley  108  (e.g., toward a disengaged position). As the cord  22  is pulled downward and out of the clutch assembly  100 , the cord  22  unwinds from clutch pulley  108  and forces the cam drive dog  114  and clutch sleeve  112  to move to the left, against the force of the spring  120 . As these parts continue to move axially to the left, they come into contact with the crown  124 . Pulling the cord  22  further causes the rotation of clutch pulley  108  to be transmitted to the crown  124  and the crown  124  in turn rotates the drive connector  136 . The drive connector  136  is inserted into tube  12  and therefore the rotation of connector  136  causes the tube  12  to rotate, thereby lowering the window covering  14 . Depending on several factors, including the length of the window covering  14 , the length of cord  22 , and the desired lower position of window covering  14 , the window covering  14  can be lowered using a single stroke of the wand  20  or multiple up and down strokes. Whenever the tension on the cord  22  is released, the elements discussed above move back to the right, disengaging from the crown  124 . Meanwhile the spring  106  retracts the cord  22  back into the clutch assembly  100  and winds it onto the pulley  108 . 
     The rotation of the tube  12  is also transmitted to the booster assembly  200 . As previously mentioned, the spring  216  is pre-tensioned and tightened as the tube  12  is rotated to lower the window covering  14 . The spring  216  normally provides the force for turning the tube  12 , raising window covering  14 . The booster system  200  is further adapted to provide damping so that the window covering  14  does not rise too quickly, but instead rises at a substantially constant speed. Finally, the booster system  200  further provides a break that ensures the tube  12  and window covering  14  remain in an intermediate position during the upward stroke of the wand  20 . 
     The position track stop  206  and ball bearing  210  are disposed in the position stop jacket  212 . This housing is fixed at the end of booster assembly  200  and it is not allowed to spin freely inside tube  12  because tube adapter  204  is keyed into a fixed position and is inserted into an end of the position of track jacket  212 . The other end of jacket  212  engages an end of the booster spring  216  and fixes this spring end so it does not rotate with tube  12 . Inside the spring jacket, there is a lateral groove arranged to keep the ball bearing  210  on one of the tracks  208  and stop it from jumping to other tracks. 
     The position stop track  206  provides a locking function for the booster assembly  200 . The tracks  208  and the ball bearing  210  cooperate to form a barrel cam with six paths that define six positions for locking and releasing the booster assembly  200 . As the tube  12  rotates, the jacket  212  rotates with the tube  12  and causes the ball bearing  210  to follow one of the tracks  208 . When the tube  12  stops, the spring  216  applies a torque on the tube  12 , thereby forcing the ball bearing  210  into one of the locking paths  208 . 
     The shaft  214 , that can be, for example, comprised of aluminum, is fixed at one end to the position stop track  206  and at the other end to the free head  218  in order to provide structural support for the booster assembly. This aids in forming a rigid assembly capable of handling large forces and torques generated by the booster spring  216 . 
     The free head  218  is attached to the other end of the booster spring  216  and is fixed to the shaft  214 . The adapter  220  secures the free head  218  within the tube  12 , but prevents it from rotating with tube  12 . Thus, the spring  216  is tightened by jacket  212 . Jacket  212  rotates with tube  12 , which in turn is rotated by connector  136 . 
     It was previously noted that in addition to wand  20 , the system  10  can be operated by pulling the window covering  14  down. When the window covering  14  is released, it moves up slightly until the ball bearing  210  is trapped in one of the stop tracks  208 , forcing the window covering  14  to stop and remain in position. Pulling the window covering  14  down slightly causes the ball bearing  210  to disengage and when the window covering  14  is then released, it is free to move up and roll onto tube  12  under the influence of spring  216 . 
     The damper or brake  224  provides damping to tube  12  so that it does not spin uncontrollably when the shade  14 , is released either directly or by wand  20 , and allowed to move up and wind onto tube  12 . 
     Details of the limiter assembly  300  are shown in  FIG. 23 . 
     Idler  326  and wheel  322  are connected to screw  320  and both support and are rotated by tube  12 . The idler  326  is free to rotate on the end of the screw  320 . Wheel  322  is engaged by the screw  320  so that as the shade goes up and down, as discussed above, the wheel  322  moves laterally along the threads of screw  320 . Initially, the screw  320  and wheel  322  are arranged so that when the shade is in its lowest position, the screw  320  is in its left most position (in the orientation shown in  FIG. 20 ) adjacent to the idler  326 . As the shade is moved up, the wheel  322  moves to the right toward the end  340  of screw  320 . The end  340  and the wheel  322  are configured so that when the wheel  322  reaches the end  340 , they engage each other, and the wheel  322  stops rotating, thereby providing an effective stop for the shade. In other words, when the wheel  322  reaches the end  340 , the window covering  14  can no longer move upwards. The thumb wheel  314  is mechanically coupled to the screw  320  so that rotating the thumbwheel  314  causes the screw  320  to rotate as well. 
     The purpose of the limiter assembly  300  is to allow an operator to select the position of the window covering  14  beyond which the window covering  14  does not move. This is accomplished as follows. First, the operator moves the window covering  14  to the desired position. As previously discussed, as the window covering  14  moves up, wheel  322  moves to the right, along screw  320  towards end  340 . When the operator stops the window covering  14  at a desired upper height H 0  (see  FIG. 1 ), the wheel  322  reaches a position X along screw  320 . At this point, the operator turns thumbwheel  314  causing the screw  320  to advance to the left through wheel  322  until end  340  reaches and engages the wheel  322  (See  FIG. 2 ). In this manner the upper limit H 0  has been set. Of course, next time the window covering  14  is lowered to its lower limit, the wheel  322  again travels to the left along screw  322 , but it no longer reaches the idler  326 . 
       FIGS. 40A-40B  show an alternate embodiment of the cord guard  400 . This cord guard  400  includes a housing  402  with two holes  404 ,  406 . The holes  404 ,  406  are disposed in a wall of the housing  402  such that they are not horizontal, but rather are offset by an angle that aligns with the direction of cord as the wand  20  is pulled. This angle may be about 20 degrees. Two rings or eyelets  108 A (shown in  FIG. 9 ) may are disposed in the holes  404 ,  406 . The cord  22  operating the window covering  14  is wound within the guard  400  and passes through hole  404  when the window covering  14  is set for a right handed operation and through hole  406  when set for a left handed operation. A blanking plug  108 B may be placed in hole  404  and hole  406  when the window covering is set for left and right handed operation, respectively, to cover the hole. 
     This configuration has several advantages. As the cord  22  is pulled successively through one of the respective holes, the friction between the cord  22  and the respective hole is reduced substantially. Therefore, the window covering  14  is easy to operate. In addition, because of this reduced frictional force, the cord  22  resists fraying or breaking. In the first embodiment shown, for example, in  FIG. 11B , the hole  108 X for the cord  22  is in a central position in order to allow the cord guard  102  to be used in either left or right-sided operation. This bilateral symmetry is maintained in the present embodiment by providing an area for an eyelet to be inserted in either or both of holes  404 ,  406 . 
     For both embodiments discussed above for the cord guard  102 , the spring  106  shown in detail in  FIG. 4  is formed with two U-shaped ends  106   a ,  106   b . The spring  106  is disposed in the core guard in a manner such that end  106   a  engages a slot  410  (see  FIG. 11B ) in the central stationary boss  104  (See  FIG. 3 ). 
     The other end  106   b  of the spring  106  is engaged in a slot  108 Z of pulley  108  (see  FIGS. 6-7 ). (Slots  108 XX and  108 YY shown in  FIG. 6  are used to hold the end of the cord  22 , one slot being used in the right-side configuration and the other for the left side configuration). Significantly, the slots for holding the ends of the spring  106  are shaped so that the spring  106  can be mounted for either operation. 
     As discussed above, in order to raise the window covering  14 , the cord  22  is pulled down. This motion causes the pulley  108  to rotate. Because the spring  106  is disposed between the stationary boss  104  and the pulley  108 , as the pulley  108  is rotated by the cord  22 , the pulley  108  rotates an end of the power spring  106 , causing the power spring  106  to tighten. When the cord  22  is released, the power spring  106  causes the pulley to reverse direction and rotate in the other direction, thereby pulling the cord  22  back into the cord guard  102 . 
     Importantly, the elements of the clutch assembly  100  and the cord guard  102  are arranged and constructed to define a space for spring  106  in such a way that the spring  106  does not come into contact or rest on any sharp edges, indentations or slots. Rather, the spring  106  only lies on or comes in contact with smooth rounded surfaces on the pulley  108  and the cord guard  102 . It has been found that any discontinuities could cause the spring  106  to bend with a small radius of curvature or force the coil to twist and distort. Any such bending and distortion of the coil can result in metal fatigue in the spring  106  and, after repeated operations, the spring  106  can break at the bending or distortion points. In the present device, these problems are substantially avoided or reduced, thereby increasing the useful life of the spring  106  and hence the whole system  10 . 
     In summary, the above-described system  10  has numerous advantages over other devices known in the art. 
     For example, because of the arrangement and structure of its components, the system  10  is slimmer and results in a smaller light gap between the system  10  and the supporting surface. 
     The system  10  requires a lower pull force to operate, especially under low or no load conditions. 
     The exit point of the cord  22  from the guard  102  is formed by an eyelet  108 A or eyelets that not only presents a low coefficient of friction, but is/are oriented to align more accurately with the cord  22  as the cord  22  is pulled in and out of the core guard  102 . This design reduces the contact surface area, as well as reduces frictional force, thereby reducing the operational force required to raise the window covering  14 . Moreover, abrasion on the cord  22  is also reduced, thereby increasing its useful life. 
     The system  10  (more specifically clutch assembly  100 ) is provided with recessed holes for engaging stationary brackets supporting the system  10 . This feature further reduces light gaps around the window covering  14 . 
     The spring used to bias the pulley  108  is arranged and supported so that it only experiences and applies radial forces, and does not experience any axial forces or other forces that may distort it. 
     The system  10  is configured to allow access to the clutch mechanism with an appropriate tool (see  FIG. 39 ). The tool extends through a hole formed in the respective end of the clutch assembly  100  and is used to adjust the booster tension while the system  10  is installed. 
     The system  10  can be mounted for either right-handed or left-sided operation and for either forward or reverse operation of the window treatment. 
     The device is provided with an adjustable limiter  300  to set and adjust a top and/or a bottom stop position for the window shade. This adjustable stop position can be set easily using a thumb wheel  314  provided on one side of the device. The thumb wheel  314  can be accessed during or after the installation of the window shade. 
     The limiter  300  and other components of the device are configured with interlocking members to ensure that the components are snapped together efficiently and securely. The limiter  300  includes a spring loaded element that is configured so that it does not interfere with the installation or removal of the window shade. 
     Although this invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. In addition, while several variations of the embodiments of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, including, but not limited to, the substitutions of equivalent features, materials, or parts, will be readily apparent to those of skill in the art based upon this disclosure without departing from the spirit and scope of the invention.