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BACKGROUND OF THE INVENTION 
       [0001]    This application claims priority from U.S. Provisional Application Ser. No. 61/645,250 filed May 10, 2012. 
     
    
       [0002]    The present invention relates to an arrangement for opening and closing coverings for architectural openings such as pleated shades and cellular shades. 
         [0003]    Usually, a transport system for a covering that extends and retracts in the vertical direction has a fixed head rail which both supports the covering and hides the mechanisms used to raise and lower or extend and retract the covering. Such a transport system is described in U.S. Pat. No. 6,536,503, Modular Transport System for Coverings for Architectural Openings, which is hereby incorporated herein by reference. In the typical covering product that retracts at the top and then extends by moving downwardly from the top (top/down), the extension and retraction of the covering is done by lift cords suspended from the head rail and attached to the bottom rail (also referred to as the moving rail or bottom slat). 
         [0004]    Some window covering products are built to operate in the reverse (bottom-up), where the moving rail, instead of being at the bottom of the window covering bundle, is at the top of the window covering bundle, between the bundle and the head rail, such that the bundle is normally accumulated at the bottom of the window when the covering is retracted and the moving rail is at the top of the window covering, next to the head rail, when the covering is extended. There are also composite products which are able to do both, to go top-down and/or bottom-up. Sometimes there is a problem with the movable rail(s) becoming skewed. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides an arrangement for moving a covering from one position to another which has advantages over prior art cord drives, eliminating many of their problems, such as eliminating loose lift cords. Some embodiments disclose the path, or routing, or “cording” of cables to prevent the movable rails from skewing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic of a prior art cording arrangement for a movable rail in which the movable rail moves along two cords that are secured, at their top and bottom ends, to the frame of an architectural opening; 
           [0007]      FIG. 2  is a schematic similar to  FIG. 1 , but with the addition of a one way brake and the use of non-stretch cables; 
           [0008]      FIG. 3  is a schematic, similar to  FIG. 2 , but with a second movable rail moving along the same two cords, and including additional brakes to hold the second movable rail in place; 
           [0009]      FIG. 4  is a schematic, similar to  FIG. 3 , but with the addition of powered lift stations to aid in keeping the second movable rail parallel to the first movable rail; 
           [0010]      FIG. 5  is another alternative schematic of two movable rails moving along two fixed cords, including double one-way brakes to assist in keeping the movable rails horizontally aligned and parallel to each other; 
           [0011]      FIG. 6  is a schematic similar to  FIG. 4 , but with the addition of a lifting mechanism in the head rail; and 
           [0012]      FIG. 7  is a section view of a one-way cable clamp lock mechanism which may be used in the embodiments shown in  FIGS. 2 ,  3 ,  4 ,  5 , and  6 . 
       
    
    
     DESCRIPTION 
       [0013]      FIG. 1  schematically illustrates a prior art blind or shade  200  with a movable rail  206 , which travels along first and second guide cables  202 ,  204 . The first guide cable  202  extends from an upper anchoring point  208  at the top left of the architectural opening  201 , under a bearing support  214  at the left end of the movable rail  206 , to the right end of the movable rail  206 , over a bearing support  216  at the right end of the movable rail  206 , to a lower, fixed anchoring point  210 * at the bottom right of the architectural opening  201 . The second guide cable  204  extends from an upper anchoring point  208 * at the top right of the architectural opening  201 , under a bearing support  216  at the right end of the movable rail  206 , to the left end of the movable rail  206 , over a bearing support  214  at the left end of the movable rail, to a lower, fixed anchoring point  210  at the bottom left of the architectural opening  201 . The cables  202 ,  204  are kept taut by an elastic member. For example, the cables  202 ,  204  themselves may be made of an elastic member, or there may be springs (not shown) between the ends of the cables  202 ,  204  and their anchor points  208 ,  208 *, which act to keep the cables  202 ,  204  taut, resulting in a system frictional force that is sufficient to keep the movable rail  206  from falling when released by the user. The left and right bearing supports  214 ,  216  may be rotatable members, such as pulleys, but they are fixed on the movable rail  206 , so their relative positions along the movable rail  206  (i.e. their axes of rotation) are fixed. (The architectural opening  201  shown here is rectangular, but it could have any desired shape. Also, while the schematic shows both cords using the same bearing supports  214 ,  216 , there actually are separate bearing supports for each cord.) 
         [0014]    The upper anchoring points  208 ,  208 * may represent tying the first ends of the first and second guide cables  202 ,  204  to a window frame, to a fixed head rail, or to some other point that is fixed relative to the opening  201 . Likewise, the lower fixed anchoring points  210 ,  210 * may represent tying off of the second ends of the first and second guide cables  202 ,  204  to the bottom of a window frame, to a fixed bottom rail, or to some other points fixed relative to the opening  201 . A covering material, such as a blind or shade, may extend from the top of the opening  201  (or from the top anchoring points  208 ,  208 *) to the movable rail  206 , or from the movable rail  206  to the bottom of the opening  201  (or to the bottom anchoring points  210 ,  210 *), or there may be two covering materials, with the first covering material extending from the top of the opening  201  to the movable rail  206  and the second covering material extending from the movable rail  206  to the bottom of the opening  201 . 
         [0015]    This arrangement is known in the prior art and is used, for instance, in shades for recreational vehicles. As described earlier, these arrangements require the first and second cables  202 ,  204  to be very taut so that, when the user moves the movable rail  206  and then releases it, there is enough system friction to hold the movable rail  206  in place. 
         [0016]    The purpose of the cording arrangement shown in  FIG. 1  is to keep the movable rail  206  horizontal (that is, so that it cannot skew). This is accomplished because the guide cables  202 ,  204  have a fixed length. If the user pulls down on the left end of the movable rail  206 , causing the length of the first cable  202  between the upper fixed point  208  and the left bearing support  214  to increase, then the length of the first cable  202  between the left bearing support  214  and the bottom fixed point  210 * must decrease a corresponding amount. This causes the right bearing support  216  to move downwardly the same distance as the left bearing support  214 , thereby keeping the movable rail  206  horizontal. (This arrangement may be referred to as horizontal cording). 
         [0017]    Referring now to  FIG. 2 , this cording is substantially identical to the horizontal cording of  FIG. 1 , except that the first and second guide cables  202 ,  204  are not kept taut by an elastic biasing means. Since the cables  202 ,  204  are no longer as taut, friction is greatly reduced and is no longer sufficient to hold the movable rail  206  in place when it is released by the user. Instead, a brake  212  is used to prevent the movable rail  206  from falling. The guide cables  202 ,  204  are fixedly secured to their respective anchoring points  208 ,  208 *,  210 ,  210 * and still travel over and under the bearing supports  214 ,  216  as in the previous embodiment. However, because the guide cables  202 ,  204  are not as tight between their respective top and bottom anchoring points, the operating force required to raise and lower the blind  200 * is reduced. These cables  202 ,  204  still are taut, in that they do not have slop or slack, but not so taut that the cables provide enough friction to prevent the movable rail  206  from falling without the aid of the brake  212 . 
         [0018]    Various types of brakes are known and could be used here. (For the purposes of this application, a brake can be distinguished from general system friction in that a brake includes a mechanism that allows the user to release the braking force, so the user does not have to act against the force of the brake to extend and retract the covering. Various types of release mechanisms are well known in the art, such as a button or lever acting against a biasing spring force, a pivoting dog brake with teeth that pivots in one direction to pinch the cord against a fixed surface and pivots in the opposite direction to release the cord, a capstan brake arrangement in which a release mechanism allows the capstan to rotate, a clutch brake with a release mechanism, and various other known brakes with various release mechanisms.) 
         [0019]    In this particular embodiment  200 *, a one-way brake  212  is used, and this particular one-way brake is a one-way cable clamp lock mechanism, similar to the off-the-shelf item supplied by GripLock systems, as shown in  FIG. 7 . The one-way brake  212  is arranged so that it provides very little resistance to the cable  204  passing from left to right through the brake  212 , which corresponds to raising the movable rail  206 , but it stops the cable  204  from moving from right to left through the brake  212 , which corresponds to lowering the movable rail  206  (or to the movable rail  206  falling). 
         [0020]    Looking now at  FIG. 7 , which shows the details of the one-way brake  212 , the housing  244  of the brake  212  is fixed relative to the movable rail  206 . The housing  244  has a generally cylindrical, tubular shape, except that the inside surface tapers to a smaller diameter at the left end. A plunger  250  also has a generally cylindrical, tubular shape, is coaxial with the housing  244 , and moves in and out longitudinally along its axis relative to the housing, with the left end of the plunger  250  projecting out beyond the left end of the housing  244 . Three ball bearings  242  are housed in the plunger  250 , and, as the plunger moves to the left, and the inside diameter of the housing  244  decreases, the ball bearings  242  are pushed inwardly, causing the ball bearings  242  to grip the cable  204  that extends through the plunger  250  and the housing  244  so the cable  204  stops moving relative to the housing  244  and relative to the movable rail  206 , which stops the movable rail  206 . 
         [0021]    A biasing spring  246  biases the plunger  250  to the left, so the brake  212  is normally locked. However, when the user grabs the movable rail  206  and raises it upwardly, the cable  204  drags the plunger  250  to the right, against the force of the spring  246 , which greatly reduces the force of the ball bearings  242  on the cable  204 , thereby releasing the braking force, so the cable  204  can travel freely from left to right through the one-way brake  212 . 
         [0022]    If the user wants to lower the movable rail  206 , he can push in on the plunger  250 , moving it to the right, against the biasing force of the spring  246 , which releases the lock  212 , allowing the cable  248  to move freely in either direction. 
         [0023]    Of course, the one-way brake  212  could be replaced by a two-way brake, which would require the user to disengage the brake both to raise and to lower the movable rail  206 . However, in the embodiment shown in  FIG. 2 , which has a one-way brake, the user only needs to push on the plunger to release the brake  212  when pulling down on the movable rail  206 . The user may raise the movable rail  206  by pushing up on the movable rail  206  anywhere along the length of the movable rail  206 , without having to handle the brake  212 . 
         [0024]    Due to the natural “horizontal bias” of the horizontal cording of  FIG. 2 , the movable rail  206  will always remain horizontal, no matter where the user applies force to raise or lower the rail  206 . The user will then be raising the rail  206  against the minimal drag of the one-way brake  212  in the non-braking direction. If the user wishes to further reduce the drag from the one-way brake  212  while raising the movable rail  206 , he may push in on the plunger  250  while raising the rail  206 . The one-way brake  212  may be located anywhere along the length of the movable rail  206  that is convenient to the user. This schematic shows the brake  212  located near the right end of the movable rail  206 , but it could be located near the left end, near the center, or in any other convenient location as long as the housing  244  of the brake  212  is fixed relative to the rail  206 . 
         [0025]    To summarize,  FIG. 2  shows a horizontal cording arrangement with the addition of a one-way brake  212  so that the guide cables  202 ,  204  are in a taut condition but are not taut enough to rely on system friction to hold the movable rail  206  in place, making it easier to raise and lower the shade  200 *. 
         [0026]      FIG. 3  shows a shade  200 ** which is similar to the shade  200 * of  FIG. 2 , but which has a second movable rail  218  added below the first movable rail  206 . This second movable rail  218  has one-way brakes  220  at each end of the rail, which are identical to the one-way brake  212 . Each of the one-way brakes  220  serves as a guide bearing where it receives its respective cable  202 ,  204 . The one-way brakes  220  are oriented so they do not interfere with raising the second movable rail  218  but prevent the second movable rail  218  from falling. When a user wants to lower the second movable rail, he engages an actuator which disengages the brakes  220  and preferably does so with a control that disengages both brakes  220  simultaneously. 
         [0027]    There is no mechanism to ensure that the second movable rail  218  remains horizontal or parallel to the first movable rail  206 . The position of the second movable rail  218  is independent of the position of the first movable rail  206 , except that the second movable rail  218  always remains below the first movable rail  206 . 
         [0028]    This covering arrangement  200 ** is suitable for operation as a top-down/bottom-up shade. To use it as a top-down/bottom-up shade, a covering material (not shown) extends from the first movable rail  206  to the second movable rail  218 . The first movable rail  206  operates exactly in the same manner as the movable rail  206  in the shade  200 * of  FIG. 2 . It may be raised by pushing up anywhere along the length of the movable rail  206 , and it may be lowered by disengaging the one-way brake  212  and pushing down anywhere along the length of the movable rail  206 . The second movable rail  218  is raised by pushing up on it, and it is lowered by disengaging the one-way brakes  220  to release their braking action and then pushing down on the second movable rail  218 . It is preferred for the user to grab the second movable rail  218  near the midpoint of the length of the second movable rail  218  when raising and lowering that rail in order to avoid skewing the second movable rail  218  and to keep it horizontal and parallel to the first movable rail  206 . 
         [0029]      FIG. 4  shows a shade  200 ′ which is similar to the shade  200 ** of  FIG. 3 , but has a take-up system to force the second movable rail  218  to remain parallel to the first movable rail  206 . In this instance, the take-up system includes two lift stations  20  (which include lift spools) and a spring motor  29  functionally interconnected by the lift rod  22 . These lift stations  20  and spring motor  29 , and their operating principles are disclosed in U.S. Pat. No. 6,536,503 “Modular Transport System for Coverings for Architectural Openings”, issued Mar. 25, 2003, which is hereby incorporated herein by reference. Very briefly, the lift rod  22  is rotationally connected to an output spool on the spring motor  29 . A flat spring (not shown) in the spring motor  29  has a first end connected to the output spool (having a first axis of rotation) of the spring motor  29 . The second end of the flat spring in the spring motor  29  is either connected to a storage spool (not shown) having a second axis of rotation, or is coiled about an imaginary axis defining this second axis of rotation. The flat spring is biased to return to its “normal” state, wound around the second axis of rotation, and typically this corresponds to when the movable rail  218  is in the fully raised position (retracted). As the movable rail  218  is pulled down (extended) the flat spring unwinds from the second axis of rotation and winds onto the output spool, increasing the potential energy stored in the spring. When the movable rail  218  is raised (retracted) the spring winds back onto the storage spool, using some of the potential energy to assist the user in raising the movable rail  218  by rotating the output spool and thus the lift rod  22  connected to the output spool of the spring motor  29 . 
         [0030]    Of course, a spring motor with drag brake may be used instead of the combination of just the spring motor  29  and the two simultaneous one-way brakes  220  for the same end result. An example of a spring motor with drag brake is disclosed in U.S. Pat. No. 7,740,045 “Spring Motor and Drag Brake for Drive for Coverings for Architectural Openings”, issued Jun. 22, 2010, which is hereby incorporated herein by reference. The spring motor  29  (or spring motor with drag brake) keeps tension on the lift cables  222  that extend between the first movable rail  206  and the second movable rail  218  and through the slats, pleated shade, or other covering material. Since the two (or more) lift stations  20  are driven together by the same lift rod  22 , they wind up and unwind the same amount of lift cable  222 , which prevents the second movable rail  218  from skewing and keeps the second movable rail  218  parallel to the first movable rail  206 . 
         [0031]    As shown in  FIG. 5 , in the parallel cording arrangement, a first cable  202  is secured at its first end to a point  208  at the upper left of the opening, goes under a bearing support  214  on the left end of the first movable rail  206 , crosses over to the right side of the first movable rail  206  along the first movable rail  206 , passing through a one-way brake  234  and then over a second bearing support  216  on the right of the first movable rail  206 , then extends down to the second movable rail  218 , passing under a third bearing support  222  on the right of the second movable rail  218 , then crosses over to the left side of the second movable rail  218 , passing through a second one-way brake  234 , then over a fourth bearing support  224  on the left end of the second movable rail, and is then secured at its second end to a point  210  at the lower left of the opening. 
         [0032]    A second cable  204  follows a mirror image of this cording arrangement. Its first end is secured to a point  208 * at the upper right of the opening. It then passes under a bearing support  226  on the right end of the first movable rail  206 , through a one-way brake  234 , over a bearing support  228  on the left of the first movable rail, down to the second movable rail  218 , under a bearing support  230  on the left of the second movable rail  218 , through a one-way brake  234 , over a bearing support  232  on the right end of the second movable rail, and its second end is secured to a fixed point  210 * at the bottom right of the opening. The bearing supports  226 ,  228 ,  230 ,  232  for the second cable  204  are separate from the bearing supports  214 ,  216 ,  222 ,  224  for the first cable  202 . Also, the one-way brakes  234  for the first cable are separate from the one-way brakes  234  for the second cable, but the one-way brakes  234  on the first movable rail  206  have a single button, lever or other actuator that disengages them both at the same time, and the same is true of the one-way brakes  234  on the second movable rail  218 . 
         [0033]    As with the previous embodiment, the one-way brakes  234  are arranged so they do not engage to interfere with the user raising the respective movable rail  206  or  218 , but they act to prevent their respective rail from falling. When the user wants to lower the respective movable rail  206  or  218 , he pushes a button or lever or other actuator to disengage the one-way brakes  234  for that respective movable rail and then pushes down on the rail. (As was explained earlier with respect to another embodiment, it would be possible to use a two-way brake instead of a one-way brake, and, in that case, the user also would have to push the button or lever or other actuator to disengage the brakes to raise the rail.) 
         [0034]    If the brakes  234  were not present, this cording arrangement would ensure that the first and second horizontal movable rails  206 ,  218  would be parallel to each other. By adding the brakes  234 , this arrangement ensures that the first and second movable rails  206 ,  218  remain both parallel and horizontal. 
         [0035]    Referring to  FIG. 5  and assuming that the brakes  234  are not present, if a user were to push down on the left side of the first movable rail  206 , causing the bearing support  214  to move downwardly and the first movable rail  206  to skew, then, since the cord  202  is in a taut condition and is fixed at both ends to fixed points, the increase in the amount of cord  202  above the bearing support  214  has to be compensated for by a decrease in the amount of cord below the bearing support  214 . This means that the second movable rail  218  also will skew, so that it remains parallel to the first movable rail  206 . 
         [0036]    If the user only moves one of the movable rails  206 ,  218  at a time, the bearing supports on the movable rail that remains stationary function as if they were the fixed end points in a horizontal cording arrangement (as explained in more detail below), thereby ensuring that the movable rail that is being moved remains parallel to the movable rail that is remaining stationary. Thus, if the rail that is remaining stationary is horizontal, then this parallel cording arrangement will ensure that the moving rail also will be horizontal. 
         [0037]    Looking at  FIG. 5  and assuming that the first movable rail  206  remains stationary, then from the point of view of the second movable rail  218 , it is in a horizontal cording arrangement like the arrangement of  FIG. 2 . The cable  202  is fixed at the bearing support  216  on the first movable rail  206 , which then provides the same function as the upper right fixed point  208 * of the horizontal cording embodiment of  FIG. 2 , and the cable  204  is fixed at the bearing support  228  of the first movable rail  206 , which then provides the same function as the upper left fixed point  208  of the horizontal cording embodiment of  FIG. 2 . 
         [0038]    Thus, in  FIG. 5 , when the first movable rail  206  is stationary, the cable  202  extends down from its top right anchoring point  216 , goes under the bearing support  222 , crosses over to the other side of the second movable rail  218 , goes over the bearing support  224  and extends down to its bottom left anchoring point  210  on the opposite side of the window opening from the top anchoring point  216 . The other cable  204  follows a mirror image routing of the first cable  202 , extending downwardly from the upper left fixed anchor point  228 , under the bearing support  230 , across the movable rail  218 , over the bearing support  232 , and then down to the lower right anchor point  210 *. This is a horizontal cording arrangement with respect to the second movable rail  218 . This means that the second movable rail  218  will behave as if it is in a horizontal cording arrangement relative to the first movable rail  206  (which in fact it is), and it will remain parallel to the first movable rail  206 . If the first movable rail  206  is horizontal and is not moved by the user, then the cording arrangement ensures that the second movable rail  218  remains horizontal (parallel to the first movable rail  206 ) as the second movable rail  218  is moved by the user. 
         [0039]    Similarly, if the situation is reversed and the second movable rail  218  is stationary while the first movable rail  206  is moved by the user, then the bearing supports  230 ,  222  of the second movable rail  218  function as the left and right lower fixed supports for the first movable rail  206 , so the cording will keep the first movable rail  206  parallel to the stationary second movable rail  218  as the user moves the first movable rail  206 . 
         [0040]    As in the embodiment of  FIG. 2 , the one-way brakes  234  allow the operator to raise each movable rail  206  or  218  without having to disengage the brakes  234 . The one-way brakes  234  prevent the rails from falling when they are released by the user, and the user actuates a button, lever, or other actuator to disengage the one-way brakes  234  on a movable rail and pushes down on that rail in order to move that respective movable rail downwardly. 
         [0041]    If the two rails  206 ,  218  become skewed relative to the architectural opening, it is a simple matter for the user to run both of the movable rails  206 ,  218  to the top or bottom of the opening to get them reoriented into the horizontal direction. The covering material in the arrangement of this shade  200 ″ typically extends between the two movable rails  206 ,  218 , the cords  202 ,  204  can pass through the covering material, and the covering can be extended and retracted without blowout (fabric stabilization). Only one cable (one cable at each end of the covering  200 ″) is exposed and this cable is advantageously located at the end of the shade, hugging the jamb, for safety. 
         [0042]    The embodiment of  FIG. 6  is the same as the arrangement shown in  FIG. 4 , except that a headrail  236  has been added, and a lift control mechanism  238  and lift cord  240  have been added. The lift control mechanism  238  is housed in the headrail  236 , and the lift cord  240  extends down from the headrail to the first movable rail  206 . The lift control mechanism  238  may be any device which causes a spool to rotate, such as a remote-controlled electric motor, for instance. A single lift cord  240  extends from the lift control mechanism  238  to the first movable rail  206 . This lift cord  240  is the only moving cord; the other cables  202 ,  204  are anchored at their respective ends so they do not move. Of course, the lift control mechanism  238  may be housed in the first movable rail  206  instead of in the top rail  236 , in which case the top rail  236  may not be needed as the upper end of lift cord  240  could be anchored directly to the frame of the window opening. 
         [0043]    The cording in this embodiment puts the first movable rail  206  in a horizontal cording arrangement, so it always remains horizontal. Thus, the lift cord  240  can be secured to the first movable rail  206  at any point along the first movable rail  206 , such as at the left end, as shown here. When the lift cord  240  starts retracting, it pulls up on the first movable rail  206 . If desired, a sleeve (not shown) may be placed over the lift cord  240  and over the portion of the cable  202  above the first movable rail  206  to enclose them together into a single sleeve. The sleeve should collapse and expand as the first movable rail  206  moves up and down. An accordion style sleeve is one example of a type of sleeve that would be suitable for this application. 
         [0044]    The lift control mechanism  238  and lift cord  240  could be added to many of the previous embodiments as well, such as the embodiments of  FIGS. 2 ,  3 , and  5 . 
         [0045]    It should be noted that a covering material (not shown) may be connected to and extend between a fixed top rail (or the top of the opening) and the first movable rail  206 ; a covering material may be connected to and extend between the first and second movable rails  206 ,  218 , and a covering material may be connected to and extend between the second movable rail  218  and a fixed bottom rail (or the bottom of the opening). And there may be any combination of such coverings. 
         [0046]    It will be obvious to those skilled in the art that modifications may be made to the embodiments described above without departing from the scope of the present invention as claimed.

Summary:
A covering for an architectural opening has a horizontal movable rail supported by cords, with a variety of configurations, some of which prevent the horizontal movable rail from skewing, most of which conceal the cords.