Abstract:
A chain control device for inhibiting movement of chains used in window blinds, shades and the like for moving the blinds between operative positions. The chain control device is secured at a location remote from the shades&#39; clutch/drive housing. The chain control device is characterized by redirecting tension forces applied by the user of the blinds away from the shade drive.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/798,012 filed Mar. 15, 2013, which application is incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to chain control devices for roller shades, curtains or blinds or the like, and more specifically to a chain control device that minimizes jamming and chain disengagement and also prompts a user to move the chain in a direction to effect a desired movement of shades or curtains and within a desired chain tension range. 
     BACKGROUND OF THE INVENTION 
     Chain operating systems for window blinds are known in the art. They generally include a sprocket or drive wheel for driving a driven blind member such as a drive shaft, a ball chain operatively engaging the sprocket wheel, a cover on the sprocket wheel and a chain stopper on the ball chain. In these systems, the sprocket wheel is drivingly connected to a driven member of a blind. For example, the blind may be a roller blind or a vertical venetian blind. A sprocket wheel can also drive other blinds, such as a horizontal venetian blind or a roman shade. The driven member can be a conventional drive shaft of a roller blind, a central control shaft of a roman shade, a lift or tilt shaft of a horizontal venetian blind or a traverse or tilt shaft of a vertical venetian blind, or the like. 
     The ball chain, in such systems, comprises a plurality of spaced apart balls. The ball chain is looped over the sprocket wheel to operatively engage it, so that first and second depending portions of the ball chain are on either side of the sprocket wheel. By pulling one of the depending portions of the ball chain, the sprocket wheel is rotated in either a clockwise or counter-clockwise direction, and the driven shaft also is rotated. This results in a roller blind being rolled up or unrolled, a venetian blind being tilted or lifted or lowered, a vertical venetian blind being traversed or tilted or a roman shade being lifted or towered. 
     The sprocket wheel, in such systems, is typically hidden with a cover. The cover generally is over at least the part of the sprocket wheel where the ball chain is looped over it, but open top covers are also known (e.g., U.S. Pat. No. 2,577,046). The cover is open at the bottom for passage of the opposite depending portions of the ball chain. The cover acts as a guiding means to guide the ball chain into engagement with the sprocket wheel and prevent the ball chain from disengaging from the sprocket wheel. 
     In such systems, ball chains have been provided with one or more separate members which act as chain stoppers. The stoppers are adapted to block movement of the ball chains into the mechanism, thus stopping the rotation of the sprocket wheels and operating movement of the blinds. They have also been used to prevent ball chain from being pulled further than necessary for performing desired operating movements of the blinds, for example, for preventing farther than a maximum tilt of a venetian blind or preventing a roller blind from being rolled-up too far whereby its bottom would collide against its roller or its housing. 
     The chain stoppers are often larger than the cross-section of the balls or entrance into the clutch covers. These stoppers thus block the ball chains at the bottom of the sprocket covers and prevent the ball chains from being further pulled over their sprocket wheels. 
     Beaded (ball) chains or cords are thus utilized in roller shades, curtains and blinds for opening or closing the roller shades, curtains or blinds in a horizontal or vertical direction. Existing beaded chains utilize a continuous headed chain in which all of the beads are of uniform size except one or two stopper beads which are of larger size. Such beaded chains introduce a purely “by chance” event when rotating the chains as there is no way for an operator to know which chain direction is going to produce the desired result. In some situations, a person desiring to open the roller shade, curtains or blinds will pull on a side of a chain/cord only to jam or disengage from the clutch mechanism. For example, excessive forces applied to the ball chain can cause the larger chain stopper to crash into the clutch housing and disengage the ball chain or cause other damage to components of the clutch. 
     In addition to frustrating the operator, pulling the beaded chain in the undesired direction introduces unnecessary wear and tear on the mechanisms of the roller shades, curtain or blinds. For example, if a roller shade is fully opened, a hard tug on the chain stresses the chain because the roller shade does not move in response to the downward pulling force. A strong tug on the chain when the roller shade is at full extension, either opened or closed, has the potential of snapping the chain, damaging the housing or clutch, or worse, pulling an entire assembly off of a wall. Similarly, a tug on the incorrect side of the beaded chain, will cause the beaded chain or the gearing to slip which, over an extended time, will degrade the rotational mechanisms of the blinds. 
     A beaded chain of the prior art does not provide an operator with the opportunity to learn which chain side to pull because the beaded chain tends to hang in such a manner that the sides of the chain are indistinguishable. For example, the chain sides often are touching or are wound around each other, and may not be in predictable locations, e.g. to the front or to the back, due to interference with the blinds, furniture, or the window sill. Further, the typical operator does not have the patience to scrutinize the chain and sprocket (not shown) to determine which side to pull. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the disadvantages and shortcomings of the prior art by providing a control device which limits chain stopper collisions with the clutch housing or cover. The present invention provides a device which limits the transfer of forces to the clutch housing, such as resulting from excessive pulling of the chain. Instead, the device redirects forces applied through the chain, particularly through the chain stopper, to a location remote from the housing and clutch assembly. 
     A device of the present invention provides a user with an indication of desired chain movement wherein chain movement is limited in one direction upon stopper contact with the device. A chain control device enables a user to manipulate roller shades in a desired manner while limiting threes applied by the chain to the clutch mechanism. 
     It is another advantage to provide a chain control device that prevents wear and tear on the clutch or drive mechanisms by tactilely prompting a user to pull the correct side of the chain or cord to effect a desired movement of the shade. The chain control device of the exemplary embodiment utilizes a spring sized to provide a tactile differentiation as the spring is compressed. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: 
         FIG. 1  is a perspective view of a roller shade and control device of the present invention. 
         FIG. 2  is a perspective view of a vertical blind and control device of the present invention. 
         FIG. 3  is a perspective view of the shade control device of  FIG. 1 . 
         FIG. 4  is a view of the beaded chain and stopper engaging the spring and spring caps of the control device of  FIG. 1 . 
         FIG. 5  is another perspective view of the shade control device of  FIG. 1   
         FIG. 6  is a cross-sectional view of the shade control device of  FIG. 1 . 
         FIG. 7  is a perspective view of the retainer of the shade control device of  FIG. 1 . 
         FIG. 8  is a perspective view of another embodiment of a shade control device of the present invention. 
         FIGS. 9 and 10  are perspective views of a third embodiment of a shade control device of the present invention. 
         FIG. 10  is a perspective view of the spring clip of the connector of  FIG. 9 . 
         FIG. 11  is a perspective view of a forth embodiment of a shade control device of the present invention. 
         FIG. 12  is a top view of the control device of  FIG. 11   
         FIG. 13  is a cross-sectional view of the control device of  FIG. 12  taken along lines  13 - 13 . 
         FIG. 14  is an exploded perspective view of the control device of  FIG. 11   
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a roller shade  2  is supported by a pair of brackets including a end plug bracket  4  and a clutch bracket  6 . A clutch  8  is provided at an end of shade  2  and is supported upon clutch bracket  6 . Clutch  8  is engaged to rotate the roller shade into a desired position by a pulling manipulation of chain  12 . A control device  10  of the present invention engages chain  12  at a location remote from the clutch  8 . Preferably control device  10  is secured to a window frame or molding or nearby wall surface. 
     Control device  10  includes a body adapted to receive portion of chain, such as ball chain  12 . Other chains, such rope or segmented metal chains may also be used. Ball chain  12  is utilized as described above to control movement of a roller shade  2 . Ball chain  12  is provided with stoppers  14 , which in this embodiment, are larger ball elements. Ball chain  12  may include multiple ball stoppers to control movement of the roller shade. For example, one ball stopper  14  may be used to delimit the upper or open position of the shade and another ball stopper  14  may be used to delimit the lower or closed position of the shade. Examples of chain drive systems for window shades include U.S. Pat. No. 4,424,852, Bead-Chain Drive System for Window Shade, and U.S. Pat. No. 5,137,073, Chain Pulling Device, each patent being incorporated by reference. 
       FIG. 2  illustrates another embodiment of a shade system include a plurality of vertical blinds  20  supported by a housing  22  and positioned by a bead chain-driven clutch  24 . Control device  10  of the present invention is positioned away from housing  22 , preferably secured to a window frame or nearby wall. Ball chain  12  and stoppers  14  are utilized to control the position of vertical blinds  20 . 
       FIG. 3  through  FIG. 7  illustrate a first embodiment of the invention. Control device  10  includes a body  30  and a pair of springs  32  held within body  30 . Spring caps  34  are inserted into ends of springs  32 . Spring caps  34  include an opening  36  through which ball chain  12  passes, but openings  36  prevent ball stoppers  14  from passing. Springs  32  and spring caps  34  are thus held within body  30 , but are free to react to forces applied by ball chain  12  and ball stoppers  14 . 
     During operation of the control device  10 , ball stopper  14  engages and compresses spring  32  held within the body  30 . Ball stopper  14  may assume other designs or configurations functioning to provide some structural differentiation to the other elements of the ball chain  12 . For simplicity of explanation, only a portion of the ball chain  12  is shown in  FIG. 3  and a second portion of ball chain  12  (not shown) would pass through other spring  32 . 
       FIG. 4  shows the spring  32 , spring caps  34 , chain  12  and stopper  14 . Ball stopper  14  engages spring  32  via lower spring cap  34 . Spring caps  34  have a first end sized to be received into the spring  32  and a second, wider end sized to engage stopper  14 . 
     Referring to  FIGS. 5 and 6 , the springs  32  and spring caps  34  are held within the body  30  by a retaining  37 . Retaining  37  is secured to the body  13  via a threaded fastener  38 . A pair of alignment pins  40  are utilized to align the retainer  37  upon body  30 , such as during assembly. The ball stoppers  14  are sized to pass through openings in retainer  37  so as to engage with springs  32  and spring caps  34 . The control device  10  is adapted to be secured to a wall or window structure with threaded fasteners passing through a pair of apertures  39  in body  30 . 
     Referring to  FIG. 7 , retaining  37  has a pair of apertures  54  through which the ball chain  12  and ball stoppers  14  can pass. The apertures  54  are sized to prevent the spring retainers caps  34  from escape out of body  30 . 
     Body  30  is adapted to be secured to a wall or other surface via threaded fasteners (not shown) passing through apertures  39 . Body  30  is secured against internal and external surfaces of the window frame or other opening. The body  30  is preferably secured at a location away from the roller shade housing. 
     In operation, the user applies tension to the chain  12  causing movement of the roller shade. The tension force being transferred to the clutch/drive assembly is effectively limited when the ball stopper  14  engages the control device  10  of the present invention. As the ball stopper  14  engages the spring cap  34 , the spring  32  is compressed within body  30 . If the user applied tension on the chain is sufficient, spring  32  is fully collapsed and the ball stopper  14  is stopped by contact with inner surfaces of the housing  30  or contact between spring retainers  34 . The device thus redirects destructive forces applied to the ball chain  12  away from the clutch housing/drive assembly to a remote location (wall, window casing, etc.) 
     Springs  32  may be held within body  30  without the use of retainer  36 . For example, the springs  32  could be inserted through an opening (not shown) at the back face of body the surface held against wall or window frame). The springs  32  could simply be compressed and inserted into an elongated cavity. The cavity could be cylindrical in form with ends tending to engage and secure the spring  32  within the body  30 . A variety of spring retention structures could be used to maintain the spring  32  within the body  30 . 
     The spring caps  34  could be eliminated by using a different spring, for example, a coil spring having reduced diameter ends. A variety of different springs could be utilized in alternative embodiments. For example, a resilient polymer spring may be utilized in place of coiled spring  32 . Or, a foam or fluid-filled shock absorbing element could be utilized in place of spring  32 . 
     The ball chains  12  could be shaped by balls formed on a chain or cord. The balls could be spherical or non-spherical. For example, a rectangular (cylindrical) stopper may be utilized. 
       FIG. 8  illustrates another embodiment of the invention which a single control device  80  is utilized with a pair of shades (not shown). The control device  80  is positioned between the pair of shades and four segments of hall chains  12  are received into the control device  80 . For simplicity of explanation, only a single ball chain  12  is shown in  FIG. 8 . The springs  32  and spring retainers  34  of control device  80  may be placed into the body  82  through openings accessible at the rear side  84  of body  82 . The chain stoppers  14  engage the springs  32  through lower openings in body  82 . 
       FIG. 9  illustrates yet another embodiment of the invention  90  where the body includes a mounting plate  92  which is generally perpendicular to a plane containing the springs  32 . The mounting plate  92  would allow the control device  90  to be mounted, for example, within a window frame interior or window moldings, depending on the application. 
       FIG. 10  is another view of the control device  90  of  FIG. 9  showing a rear access  100  through which the spring  32  and spring retainers  34  are inserted, such as during manufacture. 
       FIG. 11  is a perspective view of another embodiment of the present invention. A control device  102  include a body  113 , a pair of springs  132 , spring caps  134 , and cap retainers  135 . Cap retainers  135  secure the springs and caps  134  within body  113 . Cap retainer  135  includes a latch structure to prevent it from being dislodged. Body  113  is shown mounted to bracket  136 . Body  113  can also be directly mounted to a window frame or wall surface without the use of bracket  136 . Body  113  can be mounted to intermediate bracket  136  which is mounted to a window frame or wall surface. Bracket  136  can be used to mount the control device  102  within certain window interiors. 
       FIG. 12  is a top view of control device  102  showing body  113  secured to bracket  136  via fastener  138 .  FIG. 13  is a cross-sectional view of control device  102  taken along lines  13 - 13  in  FIG. 12 .  FIG. 14  is an exploded view of the control device  102 . 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.