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FIELD OF THE INVENTION 
     The present invention relates generally to cord keepers, and more particularly to cord keepers adapted for window treatment assemblies to take up loose cords, chains, strings, and the like, in order to protect infants and young children from potentially lethal suffocation and entanglement hazards. 
     BACKGROUND OF THE INVENTION 
     Pull-cords are utilized in various types of window treatment assemblies for operating and manipulating such window treatment assemblies such as adjusting the level of the window coverings, for example. Typically, the pull-cord consists of a single or multiple strands of threads that are typically tied together or looped. A locking device is usually provided for clamping the cords to hold the window covering at whatever height the user desires by operation of the pull-cords. The pull-cord usually extends from a head rail portion of the window treatment assembly to within a few inches or less from floor level. Such tied or looped pull-cords extending from the window treatment assembly, often presents an attractive danger to infants or young children fascinated with pull-cords. Tragically, many infants and young children playing with such pull-cords, become entangled in the pull-cords resulting in some form of injury, and even death when accidentally hanged by the pull-cords. 
     For the foregoing reasons, there is a need for a cord keeper which can effectively prevent or minimize such accidents involving infants and young children in a simple and cost effective manner. In addition, it would be desirable to design a cord keeper that is inexpensive and easy to fabricate and use, and has a minimum number of parts while possessing the durability, reliability and strength required to withstand the stress and forces often experienced during operation of window treatment assembly pull-cords. Furthermore, there is a need for a cord keeper that is especially fail-safe, and which does not require separate actions by the user. Such a cord keeper must operate efficiently, yet be aesthetically pleasing and unobtrusive. 
     SUMMARY OF THE INVENTION 
     The present invention is generally directed to a window treatment assembly pull-cord keeper comprised of minimal component parts cooperating to form a device mountable on the surface of a wall or window casing, and adapted for continuously collecting or releasing a length of a pull-cord from a window treatment assembly for keeping the pull-cord taut each time the window treatment assembly is adjusted or operated. The pull-keeper of the present invention generally comprises a wall-mountable housing, a cord collecting assembly adapted for collecting a length of a flexible cord, and biased by spring means located within the housing, that has an opening for permitting the flexible cord to pass therethrough into the cord collecting assembly. 
     The window treatment assembly typically includes window covering material or blind slats extending between a head rail and bottom rail, and two or more lift cords connected to the bottom rail. Within the head rail, there is a cord locking device located therein. Typically, two or more lift cords are connected at one end of the bottom rail, and extend up through the window covering material or blind slats into the head rail. The lift cords then pass through a cord locking device and out of the head rail in a manner where the opposite end of the lift cords, or pull-cord, is accessible to a user. The window shades or blinds are typically raised by the user pulling on the accessible portion of the lift cords, or pull-cord, and are lowered by releasing the pull-cord. In this manner, the pull-cord can extend downward from the head rail to within a few feet from floor level. 
     The window treatment assembly pull-cord keeper of the present invention is adapted to be mounted in a manner for keeping the pull-cord out of reach of infants and small children who are typically attracted to the pull-cord, and who are most susceptible to becoming dangerously entangled in the pull-cord. The pull-cord keeper of the present invention operates by collecting the freely suspended length of the pull-cord of the window treatment assembly, and keeping the ends of the pull-cord away from persons of relatively shorter stature, particularly infants and young children. More specifically, the housing of the pull-cord keeper is adapted for secure mounting on the surface of the wall or window casing near the head rail, and the cord collecting assembly located in the housing, draws or releases the pull-cord through the housing opening according to the degree of slackness in the pull-cord. The cord collecting assembly is conveniently driven by spring means in a constant spring loaded state. The user can raise or lower the bottom rail as desired while the pull-cord keeper simultaneously draws or releases, respectively, a length of the pull-cord while keeping the pull-cord taut and away from the lower end of the window treatment assembly in a safe, efficient and effective manner. When the user is satisfied with the level of the bottom rail (e.g. of a Venetian blind), the cord locking device in the head rail is engaged as usual, and the pull-cord keeper automatically maintains the taut condition in the pull-cord. No separate action on the part of the user is required for operation. 
     In particular, one aspect of the present invention is directed to a pull-cord keeper for a window treatment assembly, which comprises: 
     a wall-mountable housing; 
     a cord collecting assembly located within the housing and adapted for collecting a loose length of a flexible cord; 
     a spring adapted for rotating the cord collecting assembly to collect the loose length of the flexible cord; and 
     an opening for permitting the flexible cord to pass therethrough into the housing to the cord collecting assembly. 
     In another aspect of the present invention, the pull-cord keeper comprises: 
     a housing configured for secure mounting attachment on a wall near an upper portion of the window treatment assembly, said housing further defining a cavity therein; 
     an opening in communication with said cavity; 
     a spool adapted for rotational movement within said cavity to reel and collect through said opening a length of a slender flexible material; and 
     spring bias for biasing the spool in a rotational direction for reeling in any loose length of the slender flexible material during a constant spring loaded state. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments of the invention are described in detail below with reference to the drawings, in which like items are identified by the same reference designation, wherein: 
     FIG. 1 is a front elevational view of a typical window treatment assembly with a pull-cord keeper of the present invention illustrated in use; 
     FIG. 2 is a front perspective view looking toward the bottom of a pull-cord keeper constructed in accordance with the teachings of the present invention; 
     FIG. 3 is an exploded assembly view of the pull-cord keeper showing the component parts for one embodiment of the present invention; 
     FIG. 4A is a perspective view of a mounting plate forming part of the pull-cord keeper for one embodiment of the present invention; 
     FIG. 4B is a top plan view of the mounting plate of FIG. 4A; 
     FIG. 4C is a cross sectional view of the mounting plate taken along line  4 C— 4 C of FIG. 4B; 
     FIG. 5A is a top plan view of a spool forming part of the pull-cord keeper for one embodiment of the present invention; 
     FIG. 5B is a cross sectional view of the spool taken along line  5 B— 5 B of FIG. 5A; 
     FIG. 6 is a top plan view of a spring cartridge forming part of the pull-cord keeper for one embodiment of the present invention; 
     FIG. 7 is a top plan view of a coil spring forming part of the pull-cord keeper for one embodiment of the present invention; and 
     FIG. 8 is a cross sectional view of the pull-cord keeper for one embodiment of the present invention taken along line  8 — 8  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention can be used with any type of window treatment assembly including Venetian blinds, pleated shades, Roman shades, and the like, where a pull-cord is utilized for normal operation. Although one embodiment of the present invention is shown and described in use with Venetian blinds, the invention is not so limited. As an example of the window treatment assembly having a pull-cord which forms a loop is shown in FIG.  1 . The window treatment assembly may be a pleated shade, Roman shade, or Venetian blind. When the window covering is in an open position, the pull-cord can typically extend below the window sill to within a few inches from floor level where it can be reached easily by infants and young children. 
     The window treatment assembly  2  of FIG. 1 is shown in a closed position above a window sill  6  of a window  5 . The window treatment assembly  2 , in the form of a Venetian blind, typically includes a window covering material or blind slats  8  extending between a head rail  10  and bottom rail  12 , and two or more lift cords  14  connected to the bottom rail  12 . The head rail  10  is mounted on a top frame  7  of the window  5 . A cord locking device  16  is located within the head rail  10 . Typically, the two or more lift cords  14  are connected at one end of the bottom rail  12 , and extend up through the window covering material or blind slats  8  into the head rail  10 . The lift cords  14  then pass through the cord locking device  16  and out of the head rail  10  in a manner where the opposite end of the lift cords, or pull-cord  4 , is accessible to a user. The window shades or blind slats  8  are typically raised by disengaging the cord locking device  16  and pulling the pull-cord  4 , or lowered by releasing the pull-cord  4 . When the user is satisfied with the level of the blind slats  8 , the cord locking device  16  is re-engaged to fix the pull-cord  4  in place. 
     As further shown in FIG. 1, one embodiment of a pull-cord keeper  30  of the present invention is shown in use. The pull-cord keeper  30  is attached to the pull-cord  4  and permanently and securely mounted on a wall portion  18  near the head rail  10  of the window treatment assembly  2 . The pull-cord keeper  30  may be mounted on the window casing portion of the window  5  for a more secure structural footing. During use, the pull-cord  4  is kept safely beyond the reach of infants and young children while being easily accessible to operators of the window treatment assembly  2 . Also, the pull-cord keeper  30  advantageously does not require any separate actions on the part of the user, nor interfere with the normal operation of the window treatment assembly  2 . The user simply operates the window treatment assembly  2  in the normal manner as described above. This self-operating ability enhances the fail-safety of the pull-cord keeper of the present invention. 
     Referring to FIG. 2, the pull-cord keeper  30  is shown set apart from the wall portion  18 , looking toward the bottom and front portions. The pull-cord keeper  30  includes a cylindrical housing  32  which is adapted for securely mounting on a flat surface area of a wall or a portion of the window casing. The housing  32  comprises a cover or cap member  34  with an opening  36  in communication with an interior cavity  38  defined therein, and a mounting plate  40  with two mounting holes  42  for screw fasteners (not shown). The housing  32  is mounted to the wall  18  on a mounting surface  52  of the plate  40  which is shown hogged out for purposes of saving material and weight. The opening  38  is adapted to receive a free end of the pull-cord  4  and provides the pull-cord  4  access into the cavity  38 . During use, the pull-cord keeper  30  retracts or releases the pull-cord  4 , through the opening  38  after appropriate adjustment of the window treatment assembly  2 . The opening  38  is elongate in shape and extends circumferentially along a portion of the side of the cover  34 . 
     With reference to FIG. 3, the pull-cord keeper  30  is shown in an exploded assembly view for illustrating all of the component parts and the arrangement of such parts therein. The pull-cord keeper  30  generally includes the mounting plate  40 , a pair of screw fasteners  44 , a coil spring  46 , a spring cartridge  48 , a spool member  50 , and the cap member  34 . The coil spring  46  fits into the spring cartridge  48 . The spring cartridge  48 , in turn, fits into a central cavity of the spool  50 . The resulting assembly is enclosed within the cap member  34 , with the mounting plate  40  being secured to the open end of the cap member  34 . 
     The mounting plate  40  includes the mounting surface  52  on one side and a bearing surface  54  on an opposed interior side. In this embodiment, the mounting surface  52  is shown hogged out for reducing material usage and weight. The mounting surface  52  of the plate  40  is fastened to the wall  18  by the screw fasteners  44 . The screw fasteners  44  are inserted through the screw holes  42  from the bearing side  54  into the wall  18 . The mounting plate  40  further includes a centrally-located spindle body  56  extending perpendicularly from the bearing surface  54 , a stepped portion  58  with a pair of opposed ramped projected recesses  60  formed circumferentially thereon, and a base flange  62  extending along the periphery thereof. The spindle body  56  supports the spool  50  for rotational movement therearound and is further configured for anchoring one end of the coil spring  46  during spring loading as will be described. 
     The spool member  50  includes a cylindrical body  64  with first and second flanges  66  and  68 , respectively, and an axial bore  70  therebetween, a slot  72  extending radially through the first flange  66  and longitudinally through the side of the cylindrical body  64 , and a base portion  74  at the lower end of the axial bore  70 . The spool member  50  is free to rotate in a first direction on a bearing surface  76  of the cap member  34  for reeling a length of the pull-cord  4 , and the rotation thereof in this direction being biased by the action of the coil spring  46 . When the length of the pull-cord  4  is drawn from the keeper  30 , the spool member  50  rotates in the opposite direction being resisted by the action of the coil spring  46  for rotationally biasing the spool member  50  in the first direction, thus loading the spring  46  with each turn. The top surface of the first flange  66  of the spool member  50  includes a set of friction contact strips  78  formed thereon as will be described. 
     The slot  72  of the spool  50  allows the free end of the pull-cord  4  to be inserted into the axial bore  70 . The free end is preferably knotted to prevent the free end from slipping through the slot  72 . The remaining length of the pull-cord  4  is wound around the cylindrical body  64  and captively retained between the flanges  66  and  68 . 
     The base portion  74  and the axial bore  70  of the spool  50  forms a seat for the spring cartridge  48 . The base portion  74  further includes a centrally-located aperture  80  and a raised cupola  82  extending around the aperture  80 . The cupola  82  forms a hollow (not shown) for accommodating the free end of the pull-cord  4  occupying the axial bore  70  and supports the bottom of the cartridge  48  seated in the axial bore  70 . 
     The spring cartridge  48  includes a ridge  84  extending longitudinally along the exterior side thereof, a notch  86  in the interior side thereof coinciding with the exterior ridge  84 , and a centrally-located hole  88 . The cartridge  48  is configured to receive and retain therein the coil spring  46 . As shown in FIG. 7, the coil spring  46  includes an external tang  90 , an internal tang  92 , and a coiled body  94 . The external tang  90  is adapted to be inserted and retained in the notch  86  of the cartridge  48  as shown in FIG.  3 . With the spring cartridge  48  seated within the axial bore  70  of the spool member  50 , the ridge  84  is inserted and retained in the spool slot  72  with the bottom of the cartridge  48  resting on the raised cupola  82  above the knotted free end of the pull-cord  4 . 
     The assembled spool member  50 , cartridge  48 , and coil spring  46  are then placed into the cap member  34 . The cap member  34  is then mounted on the mounting plate  40  where the spindle body  56  is inserted through the center of the coil spring  46 , the cartridge hole  88 , and the spool bore  70  and aperture  80 . The spindle body  56  includes a slot  96  formed by two or more bosses  102  for receiving and retaining the interior tang  92  of the coil spring  46 . The cap member  34  further includes a pair of opposed ramped projection tabs  98  which cooperate with the pair of ramped projected recesses  60  adapted for secure locking engagement. The cap member  34  is slipped over the mounting plate  40  where the edge portion of the cap member  34  contacts the top surface of the mounting plate flange  62  and the sides of the stepped portion  58 . For locking of the cap member  34  to the mounting plate  40 , the projected recesses  60  and the projection tabs  98  are positioned adjacent to each other. Then, the cap member  34  is rotated in either direction on the mounting plate  40  until the tabs  98  snaps into the projected recesses  60 . The cap member  34  may be removed from the mounting plate  40  by further rotating the cap member  34  until tabs  98  disengage the projected recesses  60 . It is noted that the opening  36  of the cap member  34  in the locked position, should be directed towards the window treatment assembly  2  for efficient operation. 
     The cap member  34 , the mounting plate  40 , the spring cartridge  48 , and the spool  50  of the pull-cord keeper of the present invention consist of any durable and rigid material including, but not limited to, plastic materials such as polyamide, nylon, polyethylene, polychloropene, polyvinyl chloride, polyester, polypropylene, polystyrene, polytetrafluoroethene, and polyurethane, and the like. More preferably, the material consists of thermosetting plastics, for example, resins, melamine, polyester, Bakelite®, and the like. The coil spring  46  consists of an elastic, resilient material including, but not limited to, metals. 
     Referring to FIGS. 4A to  4 C, the mounting plate  40  is shown in greater detail. The spindle body  56  is substantially cylindrical in shape, and includes a plurality of bosses  102  for defining a pair of perpendicular slots  96  therebetween. The slots  96  are configured to receive and retain therein the interior tang  92  of the coil spring  46 . The mounting plate  40  includes a pair of ramp areas  104  each located proximate to the projected recesses  60 . The ramp areas  104  facilitates sliding of the cap member tabs  98  over the raised portion of the projected recesses  60  for tight coupling engagement between the tabs  98  and the projected recesses  60 . It is also noted that the screw holes  42  are countersunk for setting the heads of the screws flush with the bearing surface  4  of the mounting plate  40 . 
     Referring to FIGS. 5A and 5B, the spool member  50  is illustrated in greater detail. The top surface of the first flange  66  and the bottom surface of the second flange  68 , each provide bearing surfaces that cooperate with the bearing surfaces  54  and  76  of the mounting plate  40  and the cap member  34 , respectively, for sliding engagement therebetween. In addition, the edge portions of the flanges  66  and  68  also provide bearing surfaces corresponding with the interior circumferential surface of the cap member  34 . Accordingly, the spool  50  can slidingly rotate in either direction within the housing  32  formed by the cap member  34  and the mounting plate  40 . The slot  72  permits the knotted free end of the pull-cord  4  to be inserted into the hollow  100  of the base portion  74  and be captively retained therein by the spool slot  72  and the spring cartridge  48 . 
     The frictional contact strips  78  provided on the top surface of the first flange  66 , include irregular surface contours for improving frictional contact between the spool  50  and the user&#39;s finger. During installation prior to use, the user is required to wind the free end of the pull-cord  4  into the pull-cord keeper  30 . The frictional contact strips  78  assist and improve the user&#39;s gripping contact with the spool  50 , and facilitate the winding up of the pull-cord  4  prior to mounting the cap member  34  to the mounting plate  40 . The frictional contact strips  78  may include other forms such as finger indentations, rubber projections, protuberances, adhesive patches, and the like for improving the gripping contact with the user&#39;s finger on the spool  50 . In this embodiment, the frictional contact strips  78  are each rendered in the shape of an arrow for indicating to the user the rotational direction of the spool  50  for winding up the pull-cord  4  during installation as will be described. 
     Referring to FIG. 6, the spring cartridge  48  is shown in greater detail. The cartridge  48  comprises a circular base portion  106 , and a sidewall  108  extending along the periphery thereof. The ridge  84  extends radially outward from the sidewall  108  for insertion into the spool slot  72  during assembly. The coil spring, as shown in FIG. 7, is placed into the cartridge  48  for facilitating assembly of the pull-cord keeper  30 . The exterior tang  90  is placed into the notch  86  of the spring cartridge  48 . The other end of the spring  48 , or the internal tang  92  is slipped into the slot  96  of the spindle body  56  of the mounting plate  40  (see FIG. 4C) for providing an anchor point during loading of the spring  46 . 
     With reference to FIG. 8, the pull-cord keeper  30  is shown in cross section in the assembled form and mounted on a wall  18 . The knotted free end  106  of the pull-cord  4  is held captive in the hollow  100 , and extends radially away through the spool slot  72  (as shown in FIGS. 4A and 4B) and around the spool cylindrical body  64  prior to exiting the cap member opening  36 . The spool  50  with the coiled pull-cord  4 , the spring cartridge  48 , and the exterior tang  90  are rotatable as a single unit within the interior cavity  38  of the housing  32  around the spindle body  56 . During operation, the mounting plate  40 , the interior tang  92  (as shown in FIG.  7 ), and the cap member  34  remains stationary. As the pull-cord  4  is being drawn from the spool  50 , the coil spring  46  is wound up around the spindle body  56  into a spring loaded state. As the pull-cord  4  is released from the window treatment assembly  2  (i.e. window covering is raised), the spring loaded spool  50  is rotationally biased in the direction for winding up the relaxed length of the pull-cord  4  into the keeper  30 . 
     During operation, the pull-cord keeper  30  is subject to substantial torque forces and stresses associated with repeated use. The locking interaction between the tabs  98  and the projected recesses  60  are further enhanced by the spindle body  56  biasing the central portion of the cap member  34  away from the mounting plate  40  as represented by arrow  112 . This biasing effect causes the rim portion of the cap member  34  to press radially inward as represented by arrows  114 . As a result, the tabs  98  are biased into the projected recesses  60  for a tighter, more secure fit. In order to remove the cap member  34 , the cap member  34  must be rotated axially about the spindle body  56  to overcome the bias forces generated by the spindle body  56  on the cap member  34  to disengage the tabs  98  from the ramped projected recesses  60 . Removal by pulling the cap member  34  away from the mounting plate  40  requires substantial force to be applied. This enhanced locking interaction substantially improves the overall durability and reliability of the pull-cord keeper  30 . 
     With reference to FIGS. 1 to  8 , the installation and operation procedures of the pull-cord keeper will now be described. A suitable point on the wall  18  proximate the upper portion of the window treatment assembly  2  is selected. The mounting plate  40  is fastened to the point on the wall  18  by the fastening screws  44  with the spindle body  56  extending away from the wall  18 . The spool  50  is placed into the cap member  34  with the open end of the axial bore  70  oriented up. The pull-cord  4  of the window treatment assembly  2  is then drawn all the way out (i.e., raising the bottom rail  12  to the top of the window  5 ). The end of the pull-cord  4  is pulled through the opening  36  of the cap member  34 . The free end of the pull-cord  4  of the window treatment assembly is knotted and placed into the axial bore  70 . The pull-cord  4  is slipped into the spool slot  72 . The coil spring  46  is placed into the spring cartridge  48  with the exterior tang  90  occupying the cartridge notch  86 . The spring  46  and cartridge  48  are then placed into the axial bore  70  of the spool  50 . The spool assembly is then rotated in a clockwise direction or the direction indicated by the arrows rendered by the frictional contact strips  78  to wind up the pull-cord  4 . As the pull-cord  4  is wound up, the cap member  34  is transported up to the mounting plate  40  on the wall  18 . The frictional contact strips  78  improves the user&#39;s gripping contact on the spool  50  during rotation. The interior tang  92  is slotted into the spindle body  56 . The cap member  34  is oriented so that, upon locking, the opening  36  is directed towards the window treatment assembly  2 . The cap member  34  is rotated on the mounting plate  40  into a locked position where the tabs  98  snap securely into the projected recesses  60 . 
     For operation, the user simply manipulates the pull-cord  4  in the normal course of operating the window treatment assembly  2 . The pull-cord keeper  30  automatically lets out or takes in the length of the pull-cord  4  as required to maintain a taut condition. No separate action on the part of the user is required for operating the pull-cord keeper  30 . In this manner, the pull-cord  4  is always kept away from the reach of the infant or young child while permitting easy access to the adult user. 
     Although various embodiments of the invention have been shown and described, they are not meant to be limiting. Those of skill in the art may recognize various modifications to these embodiments, which modifications are meant to be covered by the spirit and scope of the appended claims.

Summary:
A pull-cord keeper is provided for a window treatment assembly with a pull-cord for operation. The pull-cord keeper includes a wall-mountable housing adapted for permanently mounting to the wall at a desired height above the floor, the housing further including a cavity defined therein and an opening in communication with the cavity, and at least one fastener for securely mounting the housing to the wall. The pull-cord keeper further includes a spool adapted for rotational movement within the cavity to reel and collect through the opening a length of the pull-cord, and a spring for biasing the spool in a rotational direction for automatically and continuously collecting any loose length of the pull-cord.