A Venetian blind is constructed include a headrail, a bottom rail, a set of slats, at least one lift cord, each lift cord having a first end fixedly fastened to the bottom rail and a second end upwardly inserted through the slats into the inside of the headrail and extended transversely to one end of the headrail and then turned downwards to the outside of the headrail, and a sleeve suspended from the headrail and adapted for receiving the second end of each lift cord for enabling the second end of each lift cord to be selectively positioned in one of a series of vertical positions in the sleeve.

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to Venetian blinds and, more specifically, to such a Venetian blind that keeps the lift cords concealed.  
           [0003]    2. Description of the Related Art  
           [0004]    A regular Venetian blind is generally comprised of a top rail, a bottom rail, a plurality of slats arranged in parallel between the top rail and the bottom rail, a lift control mechanism for controlling lifting and positioning of the bottom rail to adjust the extending area of the Venetian blind, and a tilting control mechanism for controlling the tiling angle of the slats to regulate the light. The lift control mechanism comprises a lift cord suspended from the top rail at one side for operation by hand to control the elevation of the bottom rail. Because the lift cord is exposed to the outside, it destroys the sense of beauty of the Venetian blind. Further, because a child can easily reach the exposed lift cord, an accident may occur when a child pulling the lift cord for fun. In order to eliminate this problem, Venetian blinds with receivable lift cord(s) are developed. Exemplars of these Venetian blinds are seen in U.S. Pat. Nos. 2,382,100; 5,531,257; and 3,014,124. However, these Venetian blinds are commonly have a complicated structure and high manufacturing cost.  
         SUMMARY OF THE INVENTION  
         [0005]    It is the main object of the present invention to provide a Venetian blind, which keeps the lift cords concealed and out of reach of children.  
           [0006]    It is another object of the present invention to provide a Venetian blind, which enables the user to control the lifting and positioning of the slats easily.  
           [0007]    It is still another object of the present invention to provide a lift cord concealable Venetian blind, which has a simple structure and, is inexpensive to manufacture.  
           [0008]    To achieve these objects of the present invention, the Venetian blind comprises a headrail, a bottom rail, a set of slats, at least one lift cord, each lift cord having a first end fixedly fastened to the bottom rail and a second end upwardly inserted through the slats into the inside of the headrail and extended transversely to one end of the headrail and then turned downwards to the outside of the headrail, and a sleeve suspended from the headrail and adapted for receiving the second end of each lift cord for enabling the second end of each lift cord to be selectively positioned in one of a series of vertical positions in the sleeve.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a schematic drawing of a first embodiment of the present invention, showing the Venetian blind extended out.  
         [0010]    [0010]FIG. 2 is a schematic drawing corresponding to FIG. 1, showing a received status of the Venetian blind.  
         [0011]    [0011]FIG. 3 is a schematic drawing showing the lift cord endpiece disengaged from the elongated retaining notches for free movement along the longitudinal slot according to the first embodiment of the present invention.  
         [0012]    [0012]FIG. 4 is a top view of FIG. 3.  
         [0013]    [0013]FIG. 5 is similar to FIG. 3 but showing the lift cord endpiece engaged in one elongated retaining notch of the sleeve.  
         [0014]    [0014]FIG. 6 is a top view of FIG. 5.  
         [0015]    [0015]FIG. 7 is a schematic structural view showing the connection between the lift cords and the lift cord endpiece according to the first embodiment of the present invention.  
         [0016]    [0016]FIG. 8 is a schematic structural view of a Venetian blind according to a second embodiment of the present invention.  
         [0017]    [0017]FIG. 9 is a perspective exploded view of a part of the second embodiment of the present invention, showing the structure of the winding mechanism.  
         [0018]    [0018]FIG. 10 is a schematic side view showing the bobbin of the winding mechanism locked according to the second embodiment of the present invention.  
         [0019]    [0019]FIG. 11 is similar to FIG. 10 but showing the bobbin unlocked. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]    Referring to FIGS. from  1  through  7 , a Venetian blind  10  is shown comprising a headrail  12  fixedly transversely fastened to the top side of the window, the headrail  12  having a first end  13  (the right end), a bottom rail  14  extended in transverse direction and spaced below the headrail  12 , a number of slats  16  arranged in parallel between the headrail  12  and the bottom rail  14 , a sleeve  20 , two lift cords  30 , and a lift cord endpiece  40 .  
         [0021]    The sleeve  20  is a straight tube vertically suspended from the first end  13  of the headrail  12  (alternatively, the sleeve can be fixedly fastened to one lateral side of the window), keeping the inside space in communication with the inside space of the headrail  12 . The sleeve  20  has a longitudinal slot  22  longitudinally extended between the top and bottom ends, and a plurality of elongated retaining notches  24  obliquely upwardly extended from the longitudinal slot  22  at different elevations at an equal pitch. According to this embodiment, the elongated retaining notches  24  are respectively extended from the longitudinal slot  22  at the same time. Alternatively, the elongated retaining notches  24  can be alternatively extended from the longitudinal slot  22  at two sides at different elevations.  
         [0022]    The lift cords  30  have a respective first end symmetrically fixedly fastened to the bottom rail  14 , and a respective top end upwardly inserted through a respective through hole (not shown) in each slat  16  and then inserted into the inside of the headrail  12  and then extended in the same direction toward the first end  13  of the headrail  12  and then extended downwards to the inside of the sleeve  20  (alternatively, one single lift cord may be used and inserted through a first through hole in each slat  16  and the bottom rail  14  and then inserted through a second through hole in the bottom rail  14  and each slat  16  and then extended through the headrail out of the first end  13  of the headrail  12  to the inside of the sleeve  20 ; subject to the size of the Venetian blind, three lift cords may be used).  
         [0023]    The lift cord endpiece  40  comprises a barrel-like body  41  received in the sleeve  20 , the body  41  having a bottom chamber  42  and a center through hole  43  axially disposed in communication with the bottom chamber  42 , a rod  44  perpendicularly extended from the periphery of the body  41  and extended through the longitudinal slot  22  of the sleeve  20 , and a spherical knob  45  fixedly fastened to the end of the rod  44  and disposed outside the sleeve  20 . The diameter of the rod  44  is smaller than the width of the longitudinal slot  22  and the elongated retaining notches  24 . The diameter of the spherical knob  45  is greater than the width of the longitudinal slot  22  and the elongated retaining notches  24 . The body  41  of the lift cord endpiece  40  is fastened to the second ends of the lift cords  30  inside the sleeve  20 . As illustrated in FIG. 7, the second end of each lift cords  30  is inserted through the center through hole  43  into the inside of the body  41  and then tied up into a knot inside the bottom chamber  42  of the body  41 .  
         [0024]    The Venetian blind  10  further comprises a tilting control mechanism adapted for controlling the tilting angle of the slats. Because the tilting control mechanism is of the known art and not within the scope of the claims of the present invention, no further detailed description in this regard is necessary.  
         [0025]    According to the aforesaid structure, the user can hold the spherical knob  45  of the lift cord endpiece  40  to move the lift cord endpiece  40  along the longitudinal slot  22  to the desired elevation (see FIGS. 3 and 4). When pulled the lift cord endpiece  40  downwards to lower the second ends of the lift cords  30 , the bottom rail  14  is lifted with the first ends of the lift cords  30 , thereby causing the slats  16  to be received to the headrail  12 . On the contrary, when reducing the pull force from the lift cord endpiece  40 , the bottom rail  14  will fall to the bottom side due to the effect of its gravity weight, thereby causing the slats  16  to be lowered and extended out and the lift cords to be pulled downwards with the bottom rail  14  to lift the lift cord endpiece  40 . When the user moved the lift cord endpiece  40  sideways to force the rod  44  into one elongated retaining notch  24 , as shown in FIGS. 5 and 6, the lift cord endpiece  40  is locked, and therefore the bottom rail  14  is stopped in position, keeping the blind in the corresponding extended status.  
         [0026]    As indicated above, the user can easily control the lifting and positioning of the Venetian blind  10 . Further, because the protruded sections of the lift cords  30  outside the headrail  12  are received in the sleeve  20 , the lift cords  30  are kept out of reach of children and prohibited from hooking the arm or neck of the person touching or operating the Venetian blind  10  accidentally.  
         [0027]    FIGS. from  8  through  11  show a Venetian blind according to a second embodiment of the present invention. According to this alternate form, the Venetian blind  50  comprises, a headrail  52 , a bottom rail  54 , a set of slats  56 , a sleeve  60 , a winding mechanism  70 , and two lift cords  80 . The structure and arrangement of the headrail  52 , bottom rail  54  and slats  56  of this embodiment are same as the corresponding members of the aforesaid first embodiment of the present invention. According to this embodiment, the sleeve  60  is a straight tube of rectangular cross section suspended from the headrail  52 . The top end of the sleeve  60  is fastened to the bottom side of the first end  53  of the headrail  52 . The sleeve  60  has a proper length such that the user's hand is conveniently reachable to the bottom end of the sleeve  60  for operation. The sleeve  60  has two pivot holes  63 ; 64  respectively disposed in front and rear sidewalls  61 ; 62  thereof, and a plurality of, for example, four locating holes  65  disposed in the rear sidewall  62  around the corresponding pivot hole  64 .  
         [0028]    The winding mechanism  70  is mounted in the bottom end of the sleeve  60 , comprised of a bobbin  71 , a handle  76 , and a spring  77 . The bobbin  71  comprises a body  72 , a front round rod  73  axially extended from the center of one end of the body  72 , a rear round rod  74  axially extended from the center of the other end of the body  72 , and a pin  75  protruded from one end of the body  72  adjacent to the rear round rod  74 . The round rods  73 ; 74  are respectively pivotally mounted in the pivot holes  63 ; 64  of the sleeve  60 . After installation of the bobbin  71  in the sleeve  60 , the bobbin  71  can be rotated on its own axis, and moved axially between the sidewalls  61 ; 62  of the sleeve  60  within a limited arrange (between the position shown in FIG. 10 and the position shown in FIG. 11). The handle  76  may be various shaped. According to this embodiment, the handle  76  is a crank handle fastened to the end of the front round rod  73  and disposed outside the sleeve  60  for operation by hand to rotate the bobbin  71  causing it to wind up the lift cords  80 . The spring  77  is mounted on the front round rod  73  inside the sleeve  60 , having one end stopped at the inner surface of the front sidewall  61  of the sleeve  60  and the other end stopped against one end of the body  72  of the bobbin  71 . According to this embodiment, the spring  77  is a compression spring that forces the bobbin  71  backwardly away from the front sidewall  61  of the sleeve  60  toward the rear sidewall  62 , keeping the bobbin  71  in the rear position shown in FIG. 10.  
         [0029]    The lift cords  80  each have a first end fixedly fastened to the bottom rail  54 , and a second end upwardly inserted through the slats  56  into the inside of the headrail  52  and then extended transversely to the first end  53  of the headrail  52  and then turned vertically downwards into the inside of the sleeve  60  and fixedly fastened to the periphery of the body  72  of the bobbin  71  (in the drawings, the second ends of the lift cords  80  are joined into one single rope in the sleeve  60  and then fixedly fastened to the periphery of the body  72  of the bobbin  71 ).  
         [0030]    Normally, the spring  77  holds the bobbin  71  in the rear position where the pin  75  is engaged into one locating hole  65  of the sleeve  60  to stop the bobbin  71  from rotation, keeping the second ends of the lift cords  80  fixed to the bottom end of the sleeve  60 , and therefore the bottom rail  54  is held in position. When adjusting the extending area of the blind, the user can pull the handle  76  outwards to disengage the pin  75  from the locating holes  65  of the sleeve  60  (see FIG. 11), and then rotate the handle  71  clockwise or counter-clockwise, causing the bobbin  72  to wind up or let off the lift cords  80 . When the bobbin  72  rotated clockwise to wind up the lift cords  80 , the bottom rail  54  is lifted. On the contrary, when the bobbin  72  rotated counter-clockwise to let off the lift cords  80 , the bottom rail  54  is lowered. When the bottom rail  54  adjusted to the desired elevation, release the hand from the handle  76 , enabling the pin  75  of the bobbin  71  to be forced into one locating hole  65  of the sleeve  60  by the spring power of the spring  77  to lock the bobbin  71  again (see FIG. 10).  
         [0031]    The aforesaid winding mechanism may be variously embodied. Further, a spiral or torsional spring may be used to impart a winding force to the bobbin.