Patent Publication Number: US-2012031572-A1

Title: Low Profile Roller Shade Control Unit

Description:
FIELD OF THE INVENTION 
     The invention relates generally to control units for controlling the up and down movement of a roller shade by means of a chain. 
     BACKGROUND OF THE INVENTION 
     Roller shades often incorporate a chain operated control unit for raising and lowering the blind or shade. The control unit generally incorporates a sprocket coupled to a roller tube barrel, both of which are mounted to some sort of support bracket. The roller tube barrel is inserted and mounted to one end of the roller tube which supports the blind. The roller tube barrel is in turn mounted to sprocket such that rotation of the sprocket causes the roller tube barrel to rotate in response, with the effect of raising or lowering the blind. A chain loop consisting of a plurality of beads on a string is coupled to the sprocket and used to rotate the sprocket. To prevent the chain from jamming or coming loose, the control unit is generally provided with some sort of chain guide designed to limit the movement of the chain and to keep the chain coupled to the sprocket. 
     This system of control unit is quite successful and common in the marketplace; however, it does suffer from a few drawbacks. In particular, there is always a gap separating the end of the roller tube and the support bracket holding the sprocket and roller tube barrel. As a result, a large light gap is formed between the edge of the window and the blind. Also, the design is not foolproof in preventing the chain from jamming against the edge of the blind in the control mechanism. Therefore, and improved roller shade control unit is desired. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, there is provided an improved roller shade control unit having a reduced profile resulting in a much reduced light gap. The improved roller shade control unit made in accordance with the present invention includes a flat plate and a roller tube mount rotatably mounted to the flat plate. The roller tube mount has a barrel portion with an extended edge portion extending radialy from one end of the barrel portion which rotates with the barrel portion. The control unit further includes a sprocket mounted between the flat plate and the roller tube mount. The extended edge portion of the roller tube mount is dimensioned to cover the sprocket to a peripheral edge of the sprocket. 
     In accordance with another aspect of the present invention, there is provided an improved roller shade control unit having a reduced profile for use with a roller tube and roller chain. The improved roller shade control unit including a tube housing for coupling to the roller tube and a sprocket for coupling the tube housing to the chain. The sprocket has a peripheral edge configured to couple to the chain. A chain guide for keeping the chain coupled to the sprocket is provided, said chain guide comprising a flat member having a bottom and a side, an aperture dimensioned to contain the sprocket being formed on the side. The tube housing has a barrel portion and an extended edge portion projecting radially from an end of the barrel portion, said extended edge portion configured to cover the sprocket, said extended edge portion having at least one cut out dimensioned to permit a portion of the chain to pass there through. 
     With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the preferred typical embodiment of the principles of the present invention. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view of a roller shade control unit made in accordance with the present invention. 
         FIG. 2  is a front view of a roller shade control unit made in accordance with the present invention. 
         FIG. 3  is a side view partly in section of the roller shade having the control unit made in accordance with the present invention. In the drawings like characters of reference indicate corresponding parts in the different figures. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a roller shade control unit made in accordance with the present invention is shown generally as item  10  and includes roller tube mount  12 , flat mounting plate  16  and sprocket  14  mounted between the roller tube mount and the flat mounting plate. The roller tube mount includes a barrel portion  18  and an extended edge portion  20  which extends radially away from the barrel portion. Roller tube mount  12  and sprocket  14  are both coaxially aligned and rotatably mounted to mounting element  22  of flat plate  16  such that both the roller tube mount and the sprocket can rotate relative to flat plate  16 . Flat plate  16  forms part of a mounting bracket (not shown) for mounting to a wall or window frame (not shown). Preferably roller tube mount  18  is made from one injection molded piece such that extended edge portion  20  and barrel portion  18  are integral and rotate together. Sprocket  14  is circular and has a central portion  24  which is mountable to mounting element  22  and it has a peripheral edge  26  at the peripheral edge of the sprocket. Extended portion  20  of roller tube mount  12  is sufficiently dimensioned (i.e. wide) to cover over sprocket  14  such that edge  28  of the extended portion overlaps and covers over sprocket  14  right to peripheral edge  26  so that the peripheral edge is covered by the extended portion. As best seen in  FIG. 2 , extended portion  20  has cut out sections  30  on peripheral edge  28  which are dimensioned to permit a portion of chain  32  to pass through the cut out section. In particular, cut out section  30  should be a little larger than the diameter of beads  34  making up chain  32  to permit the chain to be looped onto peripheral edge  26  of sprocket  14  by passing a portion of the chain through cut out (apertures)  30 . 
     Mount plate  16  has a chain guide  36  formed therein (or mounted thereto) which consists of a circular aperture  38  having a diameter sufficient to receive sprocket  14 . Aperture  38  is defined by wall  42  and has edge  40 . Aperture  38  and sprocket  14  are dimensioned such that peripheral edge  26  of sprocket  14  is positioned immediately adjacent wall  42  and edge  40  of chain guide  36 . Extended portion  20  is dimensioned such that peripheral edge portion  28  of the extended portion is positioned adjacent edge  40  so that sprocket  14  is entirely covered by edge portion  20  and contained within aperture  38 . As best seen in  FIGS. 1 and 2 , chain guide  36  has a lower portion  43  which has a gap  44  separating edge portion  46  from the sprocket  14 . Gap  44  is dimensioned such that a loop of chain  32  can pass through the gap so that it can be threaded onto sprocket  14 . 
     Referring now to  FIG. 3 , when assembled, control unit  10  is mounted to a wall  9  and roller tube  52  is inserted onto barrel portion  18  of roller tube mount  12 . End  55  of roller tube  52  is pushed against roller tube mount  12  such that end  55  either abuts or is immediately adjacent extended portion  20 . Since extended portion  20  rotates with roller tube mount  12 , and therefore roller tube  52 , it is less likely that edge  54  will jam in socket  14  since it is separated from the socket by extended portion  20 . By forming extended portion  20  onto roller tube mount  12 , the whole control unit  10  can be made with a very narrow profile such that light gap  56  is as narrow as possible. Indeed light gap  56  can be made to be approximately the same dimensions as the width of chain guide and plate  16 . 
     A specific embodiment of the present invention has been disclosed; however, several variations of the disclosed embodiment could be envisioned as within the scope of this invention. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.