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BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a releasable end stop for an assembly of carriers and spacers that can be moved longitudinally within a head rail of an architectural covering, such as a covering for an architectural opening, like a window or door, particularly a vertical venetian blind, in order to open and close the covering.  
           [0003]    2. Description of the Relevant Art  
           [0004]    Vertical venetian blinds have generally been provided with horizontally-extending head rails, holding a plurality of carriers or travellers that can be moved in spaced apart relationship along the longitudinal length of each head rail. Each carrier has typically supported a vertically-extending louver or slat in such a manner that the consumer of the venetian blind could: i) move the louver along the head rail (e.g., by pulling on a first operating cord or pull cord attached to an active end of the head rail); and ii) also rotate or tilt the louver about its vertical axis (e.g., by pulling on a second operating cord or tilt cord).  
           [0005]    The carriers in the head rails of vertical blinds have also generally been provided with a plurality of longitudinally-extending spacers which keep the carriers and the louvers, supported by the carriers, in spaced-apart relationship when the carriers and louvers are moved longitudinally along the head rail, apart from each other, to close the blinds and cover their windows. Typically, the closed end or leading end of each spacer has been slidably positioned on a smooth horizontal surface within a longitudinally-extending channel or groove of a leading carrier and the open end or trailing end of the spacer has been fixed to an adjacent trailing carrier. See, for example, the carriers and their spacers in U.S. Pat. No. 5,092,386, U.S. Pat. No. 4,887,657, U.S. Pat. No. 4,732,202, U.S. Pat. No. 4,559,670 and U.S. Pat. No. 4,335,775.  
           [0006]    The most trailing spacer on the most trailing carrier has typically been affixed to the active end of the head rail to keep the most trailing spacer from moving away from the active end (towards the passive other end of the head rail) when the blind has been closed. This has made it difficult to service and clean the parts of the head rail, adjacent the active end. This is because the most trailing carriers, spacers and slats have tended to block access to the head rail adjacent its active end and have not been easy to displace, even temporarily, away from the active end (i.e., longitudinally towards the passive end).  
           [0007]    In order to be able to move the most trailing carriers and slats away from the active end of the head rails of vertical blinds, releasable connections have been provided between the most trailing carriers and the active ends of the head rails. See DE 36 20 039, U.S. Pat. No. 3,157,223 and U.S. Pat. No. 5,351,741. However, such releasable connections have not been entirely satisfactory since the most trailing carriers and slats of each such vertical blind have then had to be gripped, by hand, so that they could be moved away from the active end after the most trailing carrier had been released from the active end of its blind.  
         SUMMARY OF THE INVENTION  
         [0008]    In accordance with one aspect of this invention, a releasable end stop is provided for an assembly of carriers and spacers that can be moved longitudinally within a head rail of an architectural covering, such as a covering for an architectural opening, particularly a vertical venetian blind, to open and close the covering; the end stop comprising:  
           [0009]    a longitudinally-movable release plate, in the head rail, that is between an active end cap and a trailing spacer of a most trailing carrier and that is affixed to a trailing end of the trailing spacer of the most trailing carrier; and  
           [0010]    a longitudinally-extending, flexible resilient tongue that is on the active end cap and is adapted to detachably hold the release plate against movement of the release plate away from the active end cap with longitudinal movement of the spacers and carriers away from the active end cap.  
           [0011]    With this releasable end stop, the most trailing carriers and slats can be moved easily away from the active end of the head rails of vertical blinds to clean or service the active end, simply by pushing the release plate away from the active end.  
           [0012]    Advantageously, the releasable end stop comprises a pair of tongues that are on a laterally-extending first end surface of an end plug of the active end cap; the first end surface being adjacent to the release plate. Especially advantageous is that the tongues are vertically aligned with each other and with a pair of vertically-aligned, horizontal surfaces of the release plate. Also especially advantageous is that each tongue has a hook at a leading edge, and the hooks extend towards each other, particularly where at least one of the tongues can be flexed vertically so that its hook is moved vertically, whereby a horizontal surface of the release plate can then be moved longitudinally over or under the hook to attach or detach the release plate and the end plug, quite particularly where a laterally-extending second end surface of the release plate has a pair of mating, vertically aligned, first notches, adjacent the horizontal surfaces where the first notches can be engaged and held by the hooks by moving the release plate longitudinally against the end plug. Also particularly advantageous is that both, of the tongues are highly flexible, so that the tongues can be flexed vertically to move their hooks vertically apart, whereby the horizontal surfaces of the release plate can then be moved longitudinally over or under the hooks to attach or detach the release plate from the hooks, by pushing on one vertical side of the release plate in a direction longitudinally away from the active end cap.  
           [0013]    Also advantageously, there is a downwardly- and laterally-extending tab on the underside of the release plate. Further advantageously, there is a longitudinally extending hole through the release plate to accommodate draw cords. Yet further advantageously, there is a longitudinally-extending smooth second notch through a rear portion of the release plate to accommodate a tilt rod mounting member. Still further advantageously, there is a frontally-extending projection on a front surface of the release plate, and the bottom of the projection is horizontal and smooth, so that it can slide along a longitudinally-extending track on the front of the interior of the head rail when the release plate is moved longitudinally.  
           [0014]    Other aspects of the invention include a head rail for an architectural covering, including this releasable end stop and an architectural covering, particularly a vertical venetian blind, including this head rail.  
           [0015]    Further aspects of the invention will be apparent from the detailed description below of particular embodiments and the drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a perspective view, showing the front, passive end and top of a vertical venetian blind of this invention, when closed;  
         [0017]    [0017]FIG. 2 is a perspective view, showing the front, passive end and top of the vertical blind, when closed, with its most trailing carrier moved away from its end plug;  
         [0018]    [0018]FIG. 3 is a perspective view, showing the rear, active end and bottom of the vertical blind, as shown in FIG. 2, with its detachable release plate and its most trailing carrier moved away from an end plug of its active end cap;  
         [0019]    [0019]FIG. 4 is a perspective view, showing the rear, active end and bottom of the vertical blind, as shown in FIG. 1, with its detachable release plate moved adjacent to its active end plug;  
         [0020]    [0020]FIG. 5 is a partial sectional view of the vertical blind, as shown in FIGS. 1 and 4, with its detachable release plate held by flexible resilient tongues on its active end plug;  
         [0021]    [0021]FIG. 6 is a partial sectional view of the vertical blind, as shown in FIGS. 2 and 3, with its detachable release plate moved away from the flexible resilient tongues on its active end plug;  
         [0022]    [0022]FIG. 7 is a perspective view of the vertical blind, as shown in FIGS. 1, 4 and  5 , with its head rail removed and its detachable release plate held by the flexible resilient tongues on its active end plug;  
         [0023]    [0023]FIG. 8 is a perspective view of the vertical blind, as shown in FIGS. 2, 3 and  6 , with its head rail removed and its detachable release plate moved away from the flexible resilient tongues on its active end plug;  
         [0024]    [0024]FIG. 9 is a perspective view of the detachable release plate attached to the trailing spacer of the most trailing carrier; and  
         [0025]    [0025]FIG. 10 is an exploded perspective view of the carriers, spacers, end plugs of the vertical blind of FIGS.  1 - 9 , with a slightly modified detachable release plate.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    FIGS.  1 - 10  show a vertical blind  1  having a plurality of conventional (metal, plastic or fabric) vertical louvers or slats  3  suspended from its horizontally- and longitudinally-extending head rail  4 . Passive and active end caps  5  and  6 , respectively, are provided on opposite longitudinal ends of the head rail  4 . An upper marginal portion  7  of each louver  3  is securely suspended vertically from a conventional (preferably plastic) holder  9 , each supported by a conventional (preferably plastic) carrier, generally  11 , within the head rail  4 .  
         [0027]    As shown in FIGS.  3 - 8  and  10 , a pair of conventional (preferably thin, stainless steel or plastic), longitudinally-extending elongate spacers, generally  13 , are attached to each spacer  11 . In this regard, the leading end  14 A of one spacer  13  has been slidably positioned on a smooth surface of each carrier  11 , and the trailing end  14 B of the other spacer  13  has been fixed to the carrier. Thereby, the spacers  13  keep the carriers  11  in longitudinally spaced-apart relationship when the carriers are moved longitudinally: i) from an open position, in which they are stacked adjacent the active end cap  6  when the blind  1  is open, ii) towards the passive end cap  5  and a closed position, in which the carriers are spread apart along the length of the head rail  4  when the blind  1  is closed.  
         [0028]    As also shown in FIGS.  1 - 8 , a conventional pull cord  15  is provided within the active end cap  6 . The pull cord  15  is connected by longitudinally-extending draw cords  17  (shown in FIGS.  7 - 8 ) to a leading carrier (not shown) that is closest to the passive end cap  5 . The pull cord  15  is adapted to: i) pull the leading carrier toward the passive end cap  5  and thereby pull all the other carriers  11  and the spacers  13  towards the passive end cap to close the blind  1 ; and ii) also to pull the leading carrier towards the active end cap  6  and thereby to pull the other carriers and spacers towards the active end cap  6  so as to open the blind  1 . The active end cap  6  also holds a conventional bead chain  19  which serves as a tilt cord for rotating a conventional longitudinally-extending grooved tilt rod  21  (also shown in FIGS.  7 - 8 ) of the head rail  4 , so as to tilt the holders  9  and thereby tilt their louvers  3 .  
         [0029]    As further shown in FIGS.  3 - 8  and  10 , the active end cap  6  includes an end plug  23  inserted in the active end of the head rail  4 . The active end plug  23  includes conventional longitudinally-extending openings, through which the draw cords  17  can pass to the pull cord  15  and through which the tilt rod  21  can pass to a conventional pulley (not shown), around which the bead chain  19  is wound.  
         [0030]    As still further shown in FIGS.  5 - 8  and  10 , each carrier  11  has a pair of conventional rollers or wheels  24  on its front and rear. The carrier moves on the rollers  24  along longitudinally-extending tracks  25  on the front and rear of the interior of the head rail  4 , along its length, in response to movement of the pull cord  15  and draw cords  17 .  
         [0031]    Except as described below, the head rail  4  and its components are conventional. In this regard, the structure of the carriers  11 , holders  9 , spacers  13  and louvers  3  and their controlled longitudinal movement along the length of the head rail  4  and the controlled tilt of the holders  9  and louvers  3  are generally known (e.g., from U.S. Pat. Nos. 4,732,202 and 4,335,775).  
         [0032]    In accordance with this invention, a releasable end stop, generally  26 , is provided in the head rail  4  adjacent the active end cap  6 . As shown in FIGS.  3 - 10 , the releasable end stop  26  includes a longitudinally-movable release plate, generally  27 , between the end plug  23  of the active end cap  6  and the trailing spacer  13 ′ of the most trailing carrier  11 ′ as shown in FIGS.  3 - 9 . The trailing end  14 B′ of the trailing spacer  13 ′ of the most trailing carrier  11 ′ is affixed in a conventional manner to an adjacent, laterally-extending, first end surface  29  of the release plate  27 .  
         [0033]    In addition, the releasable end stop  26  includes a pair of longitudinally-extending, flexible resilient tongues, generally  31 , on a laterally-extending second end surface  33  of the active end plug  23 , adjacent the release plate  27  as shown in FIGS.  5 - 8  and  10 . The tongues  31  are vertically aligned with each other and with a pair of vertically aligned horizontal surfaces  34  of the release plate  27 . As shown in FIGS. 7 and 8, the horizontal surfaces  34  can be on the top and bottom of the release plate  27 , or as shown in FIG. 9, one or both of such horizontal surfaces  34  can be within a longitudinally-extending hole through the release plate. Each tongue  31  has a hook  35  at its longitudinal end, adjacent the release plate  27 , and the hooks  35  of the two tongues extend towards each other. The tongues  31  are adapted to be flexed vertically when the horizontal surfaces  34  of the release plate  27  are moved longitudinally above and below the hooks  35  on the lower and upper tongues respectively as described below, either: i) towards the active end plug  23  to attach the release plate to the active end plug or ii) away from the active end plug to detach the release plate from the active end plug. The hooks  35  are adapted to hold the release plate  27  adjacent the active end plug  23 , against longitudinal movement of the release plate away from the active end cap  6  and towards the passive end cap  5  with longitudinal movement of the spacers  13  and carriers  11  away from the active end cap and towards the passive end cap to close the blind  1 . As described below, the hooks  35  are also adapted to move vertically apart when their tongues  31  are flexed vertically, and thereby to become detached from the release plate  27  so that the release plate can be moved away from the active end cap  6 .  
         [0034]    As shown in FIGS.  7 - 9 , a pair of mating, vertically-aligned, first notches  37  can be provided in the first end surface  29  of the release plate  27 . Each notch is vertically adjacent one of the horizontal surfaces  34  of the release plate where it can be engaged and held by one of the hooks  35  on the flexible tongues  31  of the active end plug  23  simply by moving the release plate  27  longitudinally against the end plug  23 . In this regard, the hooks  35  can engage and detachably hold the first notches  37  when moving the carriers  11  and louvers  3  towards the active end cap  6  to open the blind  1 . However, as seen from FIG. 10, it is not necessary to provide such first notches  37  in the release plate, in order for it to be detachably held by the hooks  35 .  
         [0035]    As shown in FIGS.  5 - 10 , a downwardly- and laterally-extending tab  39  is preferably provided on the bottom of the release plate  27  and preferably extends below the head rail  4 . The tab  39  allows one to grasp easily the release plate  27 , beneath the head rail  4 , and push the release plate longitudinally away from the active end cap  6  to detach the release plate from the hooks  35  of the flexible tongues  31  of the active end plug. In this regard, pushing the tab  39  of the release plate  27  away from the active end cap  6  initially causes the upper horizontal surface  34  of the release plate to move along the bottom surface of the upper tongue  31  towards the active end cap  6  and to urge the upper tongue upwardly, as the bottom of the release plate is moved with the tab  39  away from the active end cap  6  and the lower horizontal surface  34  of the release plate moves over the lower hook  35 . Then pushing the tab  39  of the release plate  27  further away from the active end cap  6  causes the lower horizontal surface  34  of the release plate  27  to move longitudinally away from the lower hook  35  and then moves the upper horizontal surface  34  of the release plate under and away from the upper hook  35  and away the active end cap  6 . Once detached from both hooks  35 , the release plate  27  can thereafter be moved longitudinally, with the adjacent carriers  11  and louvers  3 , further away from the active end cap  6  in order to service or clean the active end of the head rail. Subsequently, the release plate  27  can be moved, with the adjacent carriers  11  and louvers  3 , towards the active end cap  6  so that the release plate is engaged and held again by the hooks  35 . This can be done simply by pulling on the pull cord  15  to open completely the blind  1 . Preferably, the tongues  31  are made highly flexible, so that their hooks  35  are moved vertically in and out of engagement with the notches  37 , to attach and detach the hooks from the release plate  27 , and moved longitudinally above and below the horizontal surfaces  34  of the release plate without pushing too hard on the tab  39  or pulling too hard on the pull cord  15 .  
         [0036]    As shown in FIGS.  7 - 10 , a longitudinally-extending hole  41  also is preferably provided through the release plate  27  to accommodate the draw cords  17 .  
         [0037]    In addition, a longitudinally-extending smooth second notch or groove  43  is preferably provided through a rear portion of the release plate  27  as shown in FIGS.  7 - 10 . The second notch  43  accommodates a mounting member  44  for the tilt rod  21 , which member extends longitudinally from the second end surface  33  of the active end plug  23 .  
         [0038]    Moreover, a frontally-extending projection  45  is provided on the front surface of the release plate  27  as shown in FIGS.  7 - 10 . The bottom of the projection  45  is horizontal and smooth and is located so as to slide easily along the longitudinally-extending track  25  on the front of the interior of the head rail  4  when the release plate  27  is moved longitudinally. In this regard, the second notch  43  is preferably adapted also to slide easily along the tilt rod  21  when the release plate  27  is moved longitudinally.  
         [0039]    This invention is, of course, not limited to the above-described embodiments which can be modified without departing from the scope of the invention or sacrificing all of its advantages. In this regard, the terms in the foregoing description and the following claims, such as “longitudinal”, “lateral”, “above”, “below”, “top”, “bottom”, “vertical”, “horizontal”, “front”, “rear”, “frontally” and “rearwardly”, have been used only as relative terms to describe the relationships of the various elements of the releasable end stop for an assembly of carriers and spacers of a head rail of an architectural covering. For example, the louvers  3  of the vertical blinds  1  could be replaced by other vertical sections of an architectural covering, for example by: i) vertical sections of a conventional drapery fabric or a vaned fabric as described in PCT publication WO 96/35854 or ii) vertical vanes as described in PCT publication WO 96/35881. Likewise, the blind  1  could have two sets of louvers  3  and, at each longitudinal end, an active end cap  6  with a releasable end stop  26 , so that the blind can be closed by moving the sets of louvers towards each other and towards the longitudinal center of the blind, and the blind can be opened by moving each set of louvers towards one of the active end caps.

Summary:
A releasable end stop is provided for an assembly of carriers and spacers that can be moved longitudinally within a head rail of an architectural covering, such as a covering for an architectural opening, and particularly a vertical venetian blind, wherein the end stop permits movement of operative components of the covering to permit cleaning and servicing of the control system for the covering.