An anchor for attaching a pull cord to a window covering comprises a connector for attaching the anchor to the covering, a holder for connecting the pull cord to the anchor, and a clamp for releasably holding the pull cord on the holder and wherein the holder and clamp comprise a plug and socket combination and the connector is on either the holder or the clamp.

CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to European patent application No. 05076718.5, filed 26 Jul. 2005, which is hereby incorporated by reference as if fully disclosed herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to an anchor for a pull cord of a window covering, such as a roman shade, horizontal venetian blind or the like, which allows the length of the pull cord to be adjusted.  
         [0004]     2. Description of the Related Art  
         [0005]     A conventional Roman shade has a fabric shade or curtain panel which is attached to a header or head rail at the top and which can be pulled up by pull cords that are connected to a bottom portion of the panel or to a bottom bar. The pull cords are threaded through loops, rings or the like on the panel from top to bottom. Generally, a plurality of pull cords are spaced apart and parallel to each other along the length of the panel and extend from the bottom of the panel or the bottom bar to the head rail. Each pull cord is threaded through a plurality of rings, loops or the like, which are attached to the panel in vertically aligned and vertically spaced apart, parallel columns spaced apart along the length of the panel. The lower end of each pull cord is attached by a bottom knot to a ring, loop or the like on the bottom of the panel or to the bottom bar. The upper end can be routed through the head rail or through a top row of rings, loops or the like and then extend lengthwise along one side of the panel to function as an operating cord end. The upper ends of a plurality of pull cords can thus be routed to one lengthwise side of the shade and be bundled to function as an operating cord for the shade, or a separate operating cord can be attached to the bundle of pull cords. Pulling the operating cord or the pull cords directly will raise the Roman shade. Alternatively the upper end of each pull cord can be attached to a cord winding spool in the head rail, so that rotation of the winding spool will wind or unwind the pull cords and lift or lower the shade.  
         [0006]     In order that the panel hangs properly with its pull cords and its columns of rings, loops or the like extending vertically, the effective length of each pull cord relative to the panel and the other pull cords has to be carefully determined and set by the position of its bottom knot. If necessary, the length of each pull cord has to be adjusted by correcting the position of the bottom knot in relation to the length of the pull cord, the position of its bottom ring and the positions of the lower ends of the other pull cords.  
         [0007]     A conventional horizontal venetian blind has a plurality of horizontal blind slats. The slats are attached to a head rail by ladder cords and include a bottom slat or bottom rail supported by the ladder cords. The bottom slat or rail can be pulled up by pull cords that are connected to the bottom slat or rail and are threaded through the other slats up to the head rail. Generally, a plurality of pull cords are spaced apart and parallel to each other along the length of the slats and extend from the bottom slat or rail to the head rail. The lower end of each pull cord is attached by a bottom knot to the bottom slat or rail. The upper end is routed through vertically-aligned holes in the slats to the head rail and extends lengthwise to one side of the blind to function as an operating cord end. A plurality of pull cords can thus be routed to one lengthwise side of the blind and be bundled by a so-called cord equalizer to function as an operating cord, or a separate operating cord can be attached to the bundle. Pulling the operating cord or the pull cords directly will raise the blind. Alternatively, the top end of each pull cord can be attached to a cord winding spool in the head rail, so that rotation of the winding spool will wind or unwind the pull cords and lift or lower the blind.  
         [0008]     In order that the blind hangs properly with its pull cords and ladder cords extending vertically, the effective length of each pull cord relative to the height of the blind and the other pull cords has to be carefully determined and set by the position of its bottom knot. If necessary, the length of each pull cord has to be adjusted by correcting the position of the bottom knot in relation to the length of the pull cord, the position of the bottom slat or rail and the positions of the lower ends of the other pull cords.  
         [0009]     Anchors are known which can be attached to one end of a pull cord of a window covering to allow for easy attachment of the pull cord to a bottom portion of the covering, thereby obviating the need to knot the pull cords to the covering. Such anchors can also allow the effective length of the pull cord to be easily adjusted. See, for example, DE 299 22 954U and DE 102 44 033 which have a hook for attachment to a ring, loop or the like at the bottom of a covering and a clamp that can hold the pull cord and that can be disengaged from the cord in order to adjust its length.  
         [0010]     The cord anchor of DE 299 22 954U includes a base (1) with a hook (6) and a cord opening (4) in the base near the hook, through which a pull cord (3) is laced. This anchor also includes a clamp in the form of a screw (5) which is screwed into a blind hole in the base (1). The blind hole is perpendicular to the opening (4) and opens out into the opening (4), so that the pull cord (3), when threaded through the opening (4), can be clamped between the tip of the screw (5) and an inner wall of the base. The clamping action of the screw (5) depends on the extent to which the screw is turned into the base (1).  
         [0011]     The cord anchor of DE 102 44 033 includes a base (5) with a hook (6) and a cord opening (4) extending through the base, through which a pull cord (2) is laced. A second or blind hole is provided in the base (5), that is perpendicular to and crosses the opening (4) and that ends at an inner wall of the base. FIG. 2 of DE 10244033 shows the anchor as including a spring loaded pin (10) for holding the cord in place, the pin having a, opening, through which the cord can be threaded through the pin. A spring (11) is located at the end of the pin (10) and at the end of the second opening and biases the pin outwardly such that the cord (2), which is threaded through the base and the pin, is clamped between the base (5) and the pin.  
         [0012]     The clamps in these anchors act on the pull cords in a direction perpendicular to the direction in which the cords are threaded through the anchors. The clamps can engage the cords to prevent them from moving or can be disengaged from the cords to allow the engaged lengths of the cords to be adjusted.  
         [0013]     However, these anchors are relatively bulky because of the perpendicular openings in their base, needed for their clamping action. Also in the anchor of DE 29922954U, its clamping action depends upon a user screwing its screw sufficiently tight, which creates the risk that the anchor will fail if its screw is not carefully tightened. In the anchor of DE 10244033, its attachment to a cord is not simple because the cord has to be laced or threaded through its pin. Also, its spring represents an additional part which is an extra cost.  
         [0014]     It is therefore an object of the invention to provide a cord anchor which is smaller and simpler, so that it can be laced through the rings, loops or the like of a Roman shade or the openings in the slats of a venetian blind. Secondly, it is an object of the invention to provide a cord anchor which allows the length of a pull cord, held by the anchor, to be adjusted in a simple manner, and without the risk that the cord will not be tightly held by the anchor. Thirdly, it is an object of the invention to provide a cord anchor that is easy to assembly and use.  
       SUMMARY OF THE INVENTION  
       [0015]     These objects are realized by an anchor of this invention for attaching a pull cord to a window covering, which comprises a connector for attaching the anchor to the covering, a holder for connecting the pull cord to the anchor and a clamp for releasably holding the pull cord on the holder and wherein the holder and clamp comprise a plug and socket combination and the connector is on either the holder or the clamp.  
         [0016]     According to one aspect of the invention, the holder comprises the plug, the clamp comprises the socket, and the plug fits snugly into the socket. Advantageously, the plug can be positioned in the socket in at least a first or cord-engaging position and a second or cord-adjusting position.  
         [0017]     According to a second aspect of the invention, the holder or the clamp, which comprises the plug, includes a channel for receiving the cord. Advantageously, the channel is a U-shaped channel comprising a transverse, generally horizontal leg and a pair of generally vertical legs that are upstanding at the ends of the horizontal leg. Particularly advantageously, the cross-section of the vertical legs is U-shaped. More particularly, the channel has friction enhancing means.  
         [0018]     According to another aspect of the invention, a roman shade is provided comprising: a panel having a top attached to a header and a bottom; at least one pull cord attached at the bottom by an anchor, which includes a connector for attaching the anchor to the bottom, a holder for connecting the pull cord to the anchor and a clamp for releasably holding the pull cord on the holder and wherein the holder and clamp comprise a plug and socket combination and the connector is on either the holder or the clamp. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     Further aspects of the invention will be apparent from the detailed description below of particular embodiments and the drawings thereof, in which:  
         [0020]      FIG. 1  is a perspective view of a roman shade with the cord anchor of the invention;  
         [0021]      FIG. 2  is an exploded view of the anchor of  FIG. 1 ;  
         [0022]      FIG. 3  is a side view of the holder of the anchor of  FIG. 1 ;  
         [0023]      FIG. 4  is a cross-section of the clamp of the anchor of  FIG. 1 ;  
         [0024]      FIG. 5A  is a cross-section of the anchor of  FIG. 1  in a closed position, engaging a pull cord attached thereto;  
         [0025]      FIG. 5B  is a cross-section of the anchor of  FIG. 1  in a partially open position, disengaged from a pull cord attached thereto; and  
         [0026]      FIG. 6  is a schematic cross-section of a second embodiment of the cord anchor of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]      FIG. 1  shows a roman shade  1  with a fabric panel  3 , having a top rim  3 A for attachment to a header  5 , pull cords  7 ,  9 , 11  threaded through parallel, vertically-extending columns of rings  13  on rear of the panel  3 . A cord anchor  15  of this invention is on the lower portion  7 B,  9 B,  11 B of each pull cord  7 ,  9 ,  11 . Each anchor  15  includes a hook  17  for attachment to a bottom ring  13 B of each column of rings  13  near a bottom rim  3 B of the shade  3 .  
         [0028]      FIGS. 2-4  show the cord anchor  15  to have two separable parts: a holder  19  for one of the pull cords  7 ,  9 , 11 , with the hook  17  extending downwardly from the holder; and a clamp  21  for releasably holding the pull cord on the holder. The holder  19  and clamp  21  form a plug and socket combination. In this regard, an upper portion or plug  23  of the holder  19  has a vertically-elongated and rounded finger-like shape that is adapted to be inserted into the clamp  21  as described below. A lower portion  24  of the holder  19  is attached to the hook  17 .  
         [0029]     As best seen in  FIG. 3 , the upper portion or plug  23  of the holder  19  has a top  23 A and a bottom  23 B, and within the holder is a channel  25  for receiving, and accommodating movement of, one of the pull cords  7 ,  9 ,  11 . The channel  25  is generally U-shaped and has, at its bottom, a transverse, generally horizontal leg  27  that is adjacent to the bottom  23 A of the plug  23  and extends through the plug from left to right as shown in  FIG. 2 . The channel  25  also has left and right, generally vertical legs  29 ,  31  that are upstanding at the left and right ends of the horizontal leg  27  and are open at the surface of the plug  23 , on its left and right sides. Thus, the vertical channel legs  29 ,  31  divide the plug  23  into a front wall  23 F and a rear wall  23 R as shown in  FIG. 2 , and the horizontal and vertical channel legs  27 ,  29 ,  31  are preferably centered between the plug's front and rear walls  23 F,  23 R.  
         [0030]     The legs  27 ,  29 ,  31  are interconnected and together form the U-shaped channel  25  for a pull cord in the plug  23  of the holder  19 . The left and right, vertical legs  29 ,  31  each have a generally U-shaped cross-section with an upstanding base  29 A,  31 A, horizontally-extending, parallel walls  29 B,  31 B,  29 C,  31 C extending perpendicularly from left and right sides of its base  29 A,  31 A and an open top. The horizontal leg  27  has a generally square cross-section with a upstanding rear base wall base  27 A, horizontal top and bottom walls  27 B,  27 C and an upstanding front opening  27 F. The front opening  27 F is in the front wall of the plug  23 F, so that a pull cord can be inserted in the horizontal channel leg  27 .  
         [0031]     Preferably, the left and right, channel bases  29 A,  31 A have left and right, friction blocks  33 ,  35 . The friction blocks  33 ,  35  are generally rectangular projections in the vertical channel legs  29 ,  31 . Each friction block  33 ,  35  includes a top surface  33 A,  35 A, a bottom surface  33 B,  35 B and an outer surface  33 C,  35 C that is parallel to the upstanding base  29 A,  31 A of its vertical leg  29 ,  31 , so that the vertical legs are relatively shallow where the friction blocks  33 ,  35  are located. The outer surface  33 C,  35 C of each friction block preferably has a friction enhancing surface F, such as a saw-tooth profile, to better hold a pull cord in place. The friction blocks  33 ,  35  are preferably near the bottom of the vertical channel legs  29 ,  31  and level with, or just above, the horizontal channel leg  27 .  
         [0032]     The plug  23  of the holder  19  also has upper and lower, front latching notches  37 F,  39 F and upper and lower, rear latching notches  37 R,  39 R. The upper and lower notches  37 F,  37 R and  39 F,  39 R are parallel and vertically spaced apart horizontally-extending grooves in the front and rear walls  23 F,  23 R. The front upper notch  37 F is positioned over the transverse horizontal leg  27  of the channel  25  and at the same level, or just above, the top portion  33 A,  35 A of the left and right friction blocks  33 ,  35 . The front bottom notch  39 F is located just below the horizontal channel leg  27 . The rear upper and lower notches  37 R,  39 R are vertically aligned with the front upper and lower notches  37 F,  39 F. The distance between each pair of upper and lower notches  37 F,  39 F and  37 R,  39 R is thus at least equal to the sum of the vertical heights of the friction blocks  33 ,  35  and the horizontal channel leg  27 .  
         [0033]     As shown in  FIGS. 5A and 5B , one of the pull cords  7  can be looped about the plug  23  of the holder  19  and inserted in its channel  25 . This can be done by first inserting a portion of the pull cord  7  through the open portion of the opening  27 F of the horizontal channel leg  27  at the front of the plug  23 , so that the pull cord is positioned in the horizontal leg  27 , and then folding upwardly other portions of the pull cord, extending from opposite ends of the horizontal leg  27 , so that the other portions are positioned in the vertical channel legs  29 ,  31 . The pull cord positioned in the cord channel  25  can slide then along it when pulled at either end to adjust the length of the pull cord.  
         [0034]     As best seen in  FIG. 4 , the clamp  21  for releasably holding a pull cord on the holder  19  includes a hollow, vertically-elongated socket  41 , into which the plug  23  can be inserted and removed vertically. The socket  41  has a hollow, vertically-elongated and rounded interior  43  which fits closely around the exterior of the plug  23  when it is inserted in the socket  41 . The socket  41  also has an outer wall  45 , a bottom opening  47 , through which the plug  23  can be vertically inserted into, and removed from, the hollow interior  43  of the plug, and a top opening  49 , through which the ends of the pull cord can extend. The hollow interior  43  of the socket  41  has a pair of inwardly- and vertically-extending ribs  51 ,  53 , on opposite sides of the hollow interior surface  43 A of the socket  41 . Preferably the top  51 A,  53 A of each rib  51 ,  53  is adjacent the top opening  49 , and the bottom  51 B,  53 B of each rib is at approximately the middle of the height of the socket  41 . The ribs  51 ,  53  are positioned and dimensioned so that when the plug  23  of the holder  19  is inserted in the hollow interior  43  the socket  41 , the ribs  51 ,  53  slide along the vertical channel legs  29 ,  31  of the plug. A pair of slots  55 ,  57  also extend through opposite sides of the outer wall  45  of the socket  41 , beneath the ribs  51 ,  53 . The slots  55 ,  57  extend upwardly from the bottom opening  47  along a portion of the height of the outer wall  45  of the socket  41 . The slots  55 ,  57  create front and rear latches  59 ,  61  at the bottom of the socket  41  that can be flexed slightly inwardly and outwardly when the plug  23  of the holder  19  is inserted in the hollow interior  43  of the socket  41 . The latches  59 ,  61  have cams  63 ,  65  projecting horizontally into the hollow interior from inner surfaces that can resiliently engage either the upper or lower notches  37 F,  39 F or  37 R,  39 R in the front and rear walls  23 F,  23 R of the plug  23  of the holder  19  when the plug is inserted in the hollow interior  43  of the socket  41 , thereby securing the clamp on the holder.  
         [0035]     The clamp  21  and its socket  41  can be held on the plug  23  of the holder  19  of the cord anchor  15  in two positions: a cord-engaging position shown in  FIG. 5A  and a cord-adjusting position shown in  FIG. 5B . In both positions, one of the pull cords  7  and enters the anchor through the top opening  49  in the socket  41 , passes around the plug  23  through its channel  25 , past the friction blocks  33 ,  35  and exits the anchor through the top opening  49  with end portion  7 B. There are thus has two portions of the pull cord  7  extending upwardly from the top opening  49 , its end portion  7 B and an extending length  7 A as a portion of the whole pull cord  7 . In the cord-adjusting position of the cord anchor, a length of the pull cord  7  can be slid through the anchor to: reduce the effective length of the pull cord when its end portion  7 B is pulled or to increase its effective length when its other extending length  7 A is pulled.  
         [0036]     As seen in  FIG. 5A , the plug  23  of the holder  19  has been inserted to a maximum extent upwardly into the hollow interior  43  of the socket  41 , so that the cord anchor  15  is in its cord-engaging position. Thereby, the latches  63 ,  65  of the clamp  21  have been pushed into the lower, front and rear, notches  39 F,  39 R on the front and rear walls  23 F,  23 R of the plug. As a result, the ribs  51 ,  53  are directly adjacent the top surfaces  33 A,  35 A of the friction blocks  33 ,  35  in the left and right, vertical legs  29 ,  31  of the channel  25 . Also as a result, the pull cord  7  is held at two places, between the bottom ends  51 B,  53 B of the ribs and the top surfaces  33 A,  35 A of the friction blocks  33 ,  35 . Also, the pull cord is held by friction between the friction enhancing surface F of the outer surfaces  33 C,  35 C of the friction blocks  33 ,  35  and the hollow interior surface  43 A of the clamp, below the bottom ends  51 B,  53 B of the ribs  51 ,  53 . In this regard, the dimensions of the ribs  51 ,  53 , the cord channel  25  and the friction blocks  33 ,  35  are chosen such that in the cord-engaging position: i) the vertical distances between the bottom ends  51 B,  53 B of the ribs and the top surfaces  33 A,  35 A of the friction blocks are smaller than the thickness of the pull cord  7 ; and ii) the horizontal distances between the outer surfaces  33 C,  35 C of the friction blocks and the hollow interior surface  43 A of the clamp, below the bottom ends  51 B,  53 B of the ribs  51 ,  53 , are also smaller than the thickness of the pull cord.  
         [0037]     As seen in  FIG. 5B , the plug  23  has been inserted only to a partial extent upwardly into the hollow interior  43  of the socket  41 , so that the cord anchor  15  is in its cord-adjusting position. Thereby, the latches  63 ,  65  of the clamp have been pushed into the upper, front and rear, notches  37 F,  37 R on the front and rear walls  23 F,  23 R of the plug. As a result, the bottom ends  51 B,  53 B of the ribs  51 ,  53  are above the top surfaces  33 A,  35 A of the friction blocks. The ribs  51 ,  53  are thus in the vertical channel legs  29 ,  31  and directly opposite their upstanding base  29 A,  31 A. The horizontal distances between the bases  29 A,  31 A of the vertical channel legs  29 ,  31  and the ribs  51 ,  53  of the socket  41  are such that the pull cord  7  can slide along the cord channel  25 .  
         [0038]      FIG. 6  shows a second embodiment of a cord anchor  115  of the invention which is similar to the cord anchor  15  of  FIGS. 1-5  and for which corresponding reference numerals (greater by 100) are used below for describing the same parts or corresponding parts.  
         [0039]     The anchor  115  has two separable parts: a holder  119  for a pull cord  107 ; and a clamp  121  for releasably holding the pull cord on the holder. A hook  117  extends downwardly from the holder. The holder  119  and clamp  121  form a plug and socket combination. In this regard, the holder  119  has an upper portion or plug  123  that has a vertically-elongated and rounded shape with a generally conical cross-section. The plug  123  also has a U-shaped channel  125  for the pull cord  107 .  
         [0040]     An upper portion  167  of the clamp  121  includes a hollow, vertically-elongated socket  141 . A lower portion  169  of the clamp  121  is attached to the hook  117 . The socket  141  has a top opening  149 , through which the ends of the cord can extend, and a bottom opening  147 , through which the plug  123  can be inserted into, and removed from, the hollow interior  143  of the socket. The upper part of the hollow interior  143  of the socket  141  is shaped, so that the upper part of the plug  123  can be moved upwardly to fit snugly there to hold the pull cord  107  in place in a cord-engaging position of the cord anchor  115 . The hollow interior  143  of the socket  141  is also vertically long enough for the plug  123  to be moved downwardly to a top surface  171  of the upper portion  167  of the clamp  121  to a cord-adjusting position shown in  FIG. 6 . In the cord-adjusting position, the pull cord  107  can be slid through the anchor  115  to: reduce its effective length when its end portion  107 B is pulled or to increase its effective length when its other extending length  107 A is pulled.  
         [0041]     This invention is, of course, not limited to the above-described embodiments which may 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 “horizontal”, “vertical”, “right”, “left”, “front”, “rear”, “top”, “bottom”, “outer”, “inner”, have been used only as relative terms to describe the relationships of the various elements of the cord anchor of the invention as shown in the Figures.  
         [0042]     For example, instead of the open horizontal leg  27 ,  127  of the channel  25 ,  125  with its open entrance  27 F,  127 F at the front, a through hole could be provided in the left and right sides of the plug  23 ,  123  of the holder  19 ,  119 . Also for example, the cord anchor of this invention could alternatively be used to attach a pull cord to a bottom rail of a horizontal venetian blind. In such a case, an alternative to the hook  17 ,  117  would be used for connecting the anchor to the shade, such as a bayonet closure.