Abstract:
A control method for a motorized blind. The control method employs an input device that sends signals to a logic control unit. The logic control unit processes the inputs received from the input device, then controls a plurality of motors to properly control of the angle and position of the slats of a motorized blind.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
       [0002]    Not Applicable 
       REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX 
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0004]    There are a variety of means that have been employed to motorize the functions of tilting the slats of a blind to the right angle, and lifting (moving) the slats of a blind to the right position. Some of them limit motorization to only motorizing the tilt function. Others limit motorization to only motorizing the lift function. Motorized blinds have been devised that utilize a motor to control both the lift and tilt operations. These blinds connect the both lift cords and tilt cords to the same reel. In the operation of these systems, both the lifting (moving) and tilting functions occur simultaneously. Other complex mechanisms have been devised to control the lift and tilt operations in a blind. A good system that provides for independent control of the lift and tilt functions is needed. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The control method employs an input device that sends signals to a logic control unit. The logic control unit processes the inputs received from the input device, then controls a plurality of motors to properly control of the angle and position of the slats of a motorized blind. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0006]    This invention is described by the appended claims. The preferred embodiment is described and makes reference to the following figures which are explained briefly as follows. 
           [0007]      FIG. 1  is an illustration of one embodiment of the present invention in the form of a venetian blind. It is shows a blind assembly with the blind slats  2  in the lowered position and with the blind slats  2  tilted open. 
           [0008]      FIG. 2  is an overhead view of the headrail  1 . Within the head rail two tubes  28 ,  29  are illustrated. In the embodiment of this illustration, one tube  28  serves the function of driving the lift cords  32 ,  33  and the second tube  29  is responsible for the tilt function. 
           [0009]      FIG. 3  is an overhead view of a headrail  1 . In this illustration a 90-degree section of each of the tubes  28 ,  29  has been cut-away to reveal the parts within the tubes  28 ,  29 . 
           [0010]      FIG. 4  is shows an end view perspective of the blind for this embodiment. From the perspective shown in this figure, the extrusion profile of the headrail  1  can be seen. Two motor mounts  24 ,  25  can also be seen that that are mounted within the channels  7 ,  8  of the headrail  1 . 
           [0011]      FIG. 5  is a state diagram for a possible control logic unit. 
           [0012]      FIG. 6  is a circuit diagram that could be used to perform the control logic function for the described embodiment. 
           [0013]      FIG. 7  is an overhead section view of the lift tube  28 , and the tilt tube,  29  and cords  32 ,  33 ,  41 ,  42 ,  43 ,  44  that are routed in a configuration that represents one possible configuration. In this particular configuration, one of the tilt cords  41 ,  43  is routed around a diverting object  60  to create an unobstructed path for the cord  41 ,  43 . 
           [0014]      FIG. 8  is an alternate perspective of the configuration illustrated in  FIG. 7 . It is a section view as seen from section line  8 - 8  of  FIG. 7 . 
           [0015]      FIG. 9  is an overhead section view of the lift tube  28 , and the tilt tube  29 , and cords  32 ,  33 ,  41 ,  42 ,  43 ,  44 ,  90  that are routed in one possible configuration. In this particular configuration, one of the lift cords  90  is routed around a diverting object  66  to create an unobstructed path for the cord  90 . 
           [0016]      FIG. 10  is an alternate perspective of the configuration illustrated in  FIG. 9 . It is a section view as seen from section line  10 - 10  of  FIG. 9 . 
           [0017]      FIG. 11  is an overhead section view of the lift tube  28 , and the tilt tube  29 , and cords  32 ,  33 ,  41 ,  42 ,  43 ,  44  that are routed in a one possible configuration. In this particular configuration, one of the tilt cords  41 ,  43  is routed at an angle to create an unobstructed path for the cord  41 ,  43 . 
           [0018]      FIG. 12  is an alternate perspective of the configuration illustrated in  FIG. 1 . It is a section view as seen from section line  12 - 12  of  FIG. 11   
           [0019]      FIG. 13  is an overhead section view of the lift tube  28 , and the tilt tube  29 , and cords  32 ,  33 ,  41 ,  42 ,  43 ,  44  that are routed in a configuration that represents another configuration. In this particular configuration, the lift cord  32 ,  33  enters the headrail  1  at a position along the length of the headrail  1  that is different than the tilt cords  41 ,  42 ,  43 ,  44  to an unobstructed path for all of the cords  32 ,  33 ,  41 ,  42 ,  43 ,  44 . 
           [0020]      FIG. 14  is an alternate perspective of the configuration illustrated in  FIG. 13 . It is a section view as seen from section line  14 - 14  of  FIG. 13 . 
           [0021]      FIG. 15  is an overhead section view of the lift tube  28 , and the tilt tube  29 , and cords  32 ,  33 ,  41 ,  42 ,  43 ,  44 ,  90  that are routed in a configuration that represents another possible configuration. This particular configuration employs two lift cords  32 ,  33 ,  90 . In this configuration, the one of the lift cord  90  enters the headrail I at a position along the length of the headrail  1  that is different than the point where the other lift cord  32 ,  33  and tilt cords  32 ,  33 ,  41 ,  42 ,  43 ,  44  enter. The result is another unobstructed path for all of the cords  32 ,  33 ,  41 ,  42 ,  43 ,  44 , 90 . 
           [0022]      FIG. 16  is an alternate perspective of the configuration illustrated in  FIG. 15 . It is a section view as seen from section line  16 - 16  of  FIG. 15 . 
           [0023]      FIG. 17  is a section view that shows the tilt tube  29  on the left and the lift tube  28  on the right. In this illustration one of the lift cords  32 ,  33 ,  90  is routed around each side of the tilt tube  29  to create an unobstructed path for the cords  32 ,  33 ,  41 ,  42 ,  43 ,  44 ,  90 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    The preferred embodiment describes a venetian blind application. However, it is applicable to any type of blind that employs a plurality of parallel slats  2  including venetian blinds, vertical blinds, cloth blinds such as those that suspend fabric slats between two sheer fabric facings, and other types of blinds with slats. A group of slats  2  is a group a group of parallel members that allows light to pass when the slats are angled in one particular direction, but which substantially blocks light when the angle has changed. These parallel members may be called slats, vanes, ribbons, strips, planks, blades, or other names. However, here they are referred to simply as slats  2 . Throughout the description, the function of changing the physical location, or position, of the slats is referred to as lift, or lifting. The function of changing the angle of the slats  2  is referred to as tilt, or tilting. 
         [0025]    Many different embodiments are possible. The preferred embodiment describes one particular venetian blind, however, practical application other embodiments of venetian blinds, and to other types of blinds, can be carried out by those skilled in the art. 
         [0026]    The preferred embodiment utilizes a pair of motors  19 ,  20 . The first motor  19  serves the purpose of driving the lift function of the blind, and the second motor  20  serves to drive the tilt function of the blind. Both motors  19 ,  20  are contained within the same headrail  1 . The type of motor selected for the preferred embodiment is commonly referred to as a tubular motor. The tubular motors used in this embodiment are bi-directional motors that include a self-contained gearbox, brake, and limit switches. Each of the motors  19 ,  20  is mounted rigidly to the headrail  1 . A tube  28 ,  29  is placed around the motors  19 ,  20  and an adapter  34 ,  40  connects the drive shaft of the motor to the tube so that the power of the motor causes the tube to rotate around the motor. In this embodiment the tube becomes a reel for the cords.  FIG. 1  depicts the preferred embodiment of a venetian blind. It shows the headrail  1 , lift cords  32 ,  33 , tilt cords  41 ,  42 ,  43 ,  44 , slats  2 , and bottomrail  3 .  FIG. 2  shows a close-up view of the headrail  1  and the components installed in the headrail  1 .  FIG. 3  is a closer up view the same headrail  1  with a section of the tubes  28 ,  29 , cut-away to reveal the components inside. The headrail  1  itself in the preferred embodiment is made from extruded aluminum. Along both top edges of the headrail is a lip  4 . This lip  4  serves to reinforce and add strength. The headrail  1  also has two channels  7 ,  8  along the bottom that are an integrated part of the extrusion profile. These channels  7 ,  8  serve the function of holding the motor mounts  11 ,  12 ,  24 ,  25  in the correct position. The motor mounts  11 ,  12 ,  24 ,  25  are also screwed into place to prevent them from sliding within the channel  7 ,  8 . In this embodiment four motor mounts  11 ,  12 ,  24 ,  25  are used: one for the lift tube  24 , one for the lift motor  11 , one for the tilt tube  25 , and one for the tilt motor  12 . The mounts for the lift motor  19  and lift tube  28  are placed in the first channel  7  and the motor mounts for the tilt motor  20  and tilt tube  29  are placed in the second channel  8 . Screws are used to hold all four motor mounts  11 ,  12 ,  24 ,  25  in place. The screws are inserted through the bottom side of the headrail  1  up into the motor mount  11 ,  12 ,  24 ,  25 . Other methods of mounting the motors  19 ,  20  are possible. 
         [0027]    The motors used in this embodiment of the invention are tubular motors. These motors commonly used today in awnings, projection screens, and blinds. These tubular motors have several integrated features: they are bidirectional, they have integrated gearboxes, they have integrated limit switches, and they have an integrated electromagnetic brake. Components on these motors include a mounting shaft  81 ,  82 , a limit switch driver  14 ,  35 , limit switch set screws  15 ,  16 ,  17 ,  18 , a motor body  19 ,  20 , and a drive shaft  21 ,  22 . The tubular motors  19 ,  20  typically have a four-sided, square, mounting shaft  81 ,  82 . In this embodiment this mounting shaft  81 ,  82  is inserted into a complementary hole in the motor mount  11 ,  12 . Then a pin  23  is placed through the hole in the mounting shaft  81 ,  82  to keep the mounting shaft  81 ,  82  from sliding out of the motor mount  11 ,  12 . 
         [0028]    The first motor mount  11  for the lift motor  19  is connected in this manner. The motor mount  24  for the second end of the lift motor  19  is also inserted in the first channel  7  in the headrail  1  and is attached with screws. However, in this embodiment the motor mount  24  doesn&#39;t attach directly to the motor  19 . Instead, the motor mount  24  for the lift tube  28  has a round hole in it. A bolt  26  is placed through the hole in the motor mount. A nut  27  is used to secure the bolt  26  in place. Washers  30  are used, one on each side of the motor mount  24 . Onto the bolt  26 , a threaded tube adapter  31  is installed. The threaded tube adapter  31  has internal threads that match the threads of the bolt  26 . The threaded tube adapter  31  is effectively screwed onto the bolt  26 . The threaded tube adapter  31  is inserted into the first end of the lift tube  28 . Screws are used to secure the lift tube  28  to the threaded tube adapter  31 . The purpose of the bolt  26  and threaded tube adapter  31  is to cause the tube to travel axially as tube spins. This axially movement allows the lift cords  32   33  to wind evenly, without overlap, as the tube  28  spins. The result is that the bottomrail  3  remains level as it rises. Other methods to wind the cords evenly are possible. 
         [0029]    To link the power of the motor  19  to the tube  28  a drive adapter  34  is used. The drive adapter  34  couples the drive shaft  21  of the motor to the tube  28 . The drive shafts  21   22  of tubular motors  19   20  typically have two flat sides that are parallel to each other and two rounded sides that are opposite each other. The drive adapter  34  fits onto the output shaft  21  and is normally held in place with a clip that fits into a groove  69  in the end of the drive shaft  21 . The drive adapter  34  has physical contours on its exterior surface that fit complementary physical contours on the interior of the tube  28 . This arrangement connects the motor  19  to the tube  28 . No screws are used to connect the drive adapter  34  to the lift tube  28 . The tube  28  is allowed to slide axially over the drive adapter  34  as the drive shaft  21  spins. 
         [0030]    The second end of the tube  28  attaches to the limit switch receiver  35  on the motor  19 . The limit switch receiver  35  on the motor  19  is driven by the tube  28 . The limit switch receiver  35  also serves the function of supporting the end of the lift tube  28 . The lift tube  28  is allowed to slide axially over the limit switch receiver  35 , consequently the limit switch receiver  35  is long enough to support the lift tube  28  throughout the total distance that the lift tube  28  may travel. To make this possible the limit switch receiver  35  is connected to the limit switches that are integrated into the motor  19 . 
         [0031]    There are two limit-switch set screws on the motor  15 ,  16 . The first set screw  15  determines that maximum clockwise position of the motor and the second set screw  16  determines the maximum counterclockwise position of the motor. The rotational limits of the motor  19  can be set by turning the screws  15 ,  16  to the appropriate position. When the motor  19  reaches the predetermined position, as determined by the set screws  15 ,  16 , the motor  19  stops. The  32 ,  33  lift cords need to be joined to the tube  28 . Many different means of accomplishing this are possible. In this embodiment, the tube is provided with a groove  69  that has a dimension that precisely matches the dimension of the cord mount  36 ,  37 . The cord mount  36 ,  37  fits within the groove  69  in the tube  28 . It is designed to be a precise enough fit so that pressure holds the cord mount  36 ,  37  in place within the groove  69 . However, adhesive can be used to secure cord mounts  36 ,  37  that may be out of tolerance. The lift cords  32 ,  33  fit under the cord mount  36   37 . To keep the lift cords  32 ,  33  from sliding out, a small grommet  38   39  is crimped onto the end of the cord  32 ,  33 . 
         [0032]    In this embodiment, two motor mounts are used to support the tilt motor  12  and tilt tube  25 . Both mounts  12   25  fit within the second channel  8  in the headrail  1 . Both motor mounts  12   25  are held into place with screws. The screws go through holes in the bottom of the headrail  1  and extend up into the motor mounts. The first motor mount  12  has a square hole in it that is coupled directly to the mounting shaft  82  of the first motor  20 . The second motor mount  25  doesn&#39;t mount directly to the motor  20 , but rather connects to an idler  39 . The idler  39  fits within the end of the tilt tube  29 . The idler  39  serves the purpose of holding the end of the tube  29  in a fixed position, while allowing it to simultaneously rotate freely. The idler  39  may have ball bearings to allow it to rotate freely. 
         [0033]    To couple the power of the tilt motor  20  to the tube  29  a drive adapter  40  can be used. The drive adapter  40  connects the drive shaft  22  of the tilt motor  20  to the tube  29 . The drive adapter  40  fits onto the drive shaft  22  and is normally held in place with a clip that fits into a groove  65  in the end of the drive shaft  22 . The drive adapter in this embodiment  40  has physical contours on its exterior surface that match up with complementary features on the interior of the tilt tube  29  so that the motion of the drive shaft  22  causes the drive adapter  40  to spin. The motion of the drive adapter  40  causes the tube  29  to spin. 
         [0034]    Two different types of lift cord configurations are commonly used today in venetian blinds. The first method uses a single lift cord at each lift point. The second method utilizes two lift cords  32 ,  33 ,  90  at each lift point. In both methods, the lift cords  32 ,  33 ,  90  run vertically from the headrail down to the bottom of the blind. They attach to the bottomrail  3  and perform the function of lifting the bottomrail  3 . Many venetian blinds have just two lift points, one near each end of the blind. However, wider blinds may have additional lift points interposed between the lift points near either end of the blind. With the single-lift-cord method holes are commonly placed through each slat  2  and the lift cord  32 ,  33 ,  90  is routed through the holes. The dual-lift-cord method doesn&#39;t normally utilize slats  2  with holes them holes in them. Instead the lift cords  32 ,  33 ,  90  are routed with one lift cord  32 ,  33   90  on each side of the slats  2 . Embodiments of these common lift cord configurations are described in the section below. Other configurations of lift cords  32 ,  33 ,  90  are possible. 
         [0035]    In an embodiment of the single-lift cord configuration, one end of the lift cord  32 ,  33 ,  90  is attached to the bottomrail  3 . The lift cord  32 ,  33 ,  90  is then routed up through a hole in each of the blind slats  2 . After being routed through a hole in each of the blind slats  2  it is routed through a hole  50  in the bottom of the headrail  1 . It is then routed to the lift tube  28 . After reaching the lift tube  28 , the lift cord  32 ,  33 ,  90  is then routed under a cord mount  36 . A small metal cylinder  38  is crimped onto the end of the cord  32 ,  33 ,  90  to prevent the lift cord  32 ,  33 ,  90  from slipping out. Each of the lift cords  32 ,  33 ,  90  is routed in the manner just described. Each of the lift cords  32 ,  33 ,  90  are the same length so that the bottomrail  3  is horizontal and that the slats  2  remain horizontal as they rise. 
         [0036]    An embodiment of the dual-lift cord configuration uses two lift cords  32 ,  33 ,  90  at each lift point. For example, a blind with three lift points, will consequently use six lift cords  32 ,  33 ,  90 . In the dual-lift cord configuration, a first lift cord  32 ,  33 ,  90  is attached to the front face of the bottomrail  3 , and a second lift cord  32   33  is attach the opposite face of the bottomrail  3 . Both of the lift cords  32 ,  33 ,  90  are normally be attached a point on the bottomrail  3  directly opposite each other. The lift cords  32 ,  33 ,  90  are then routed upward, with one cord on each side of the blind slats  2 . After being routed past all of the blind slats  2 , the lift cords  32 ,  33 ,  90  are then routed through a hole in the bottom of the headrail  1 . They are then routed to the lift tube  28 . To attach to the lift cords  32 ,  33 ,  90  to the lift tube  28  in this embodiment, the lift cords  32   33  are routed under a cord mount  36 . Then a small metal cylinder  38  is crimped onto the end of the lift cord  32 ,  33 ,  90  to prevent it from slipping out. 
         [0037]    Tilt cords  41 ,  42 ,  43 ,  44  can be secured to the tubes  29  using the same method that is used for the lift cords  32 ,  33 ,  90 . Tilt cords  41 ,  42 ,  43 ,  44  can be joined to the tilt tube  29  using a cord mount  63 ,  64 . In this embodiment the tube  29  is provided with a groove  65  that has a dimension that closely matches the dimension of the cord mount  63 ,  64 . In this embodiment the cord mount  63 ,  64  fits within the groove  65  in the tube  29 . A precise fit between the groove  65  and the cord mount  63 ,  64  can hold the cord mount  63 ,  64  in position. Alternatively, adhesive can be used to secure the cord mounts  63   64 . Then to keep the tilt cords  41 ,  42 ,  43 ,  44  from sliding out, a small metal cylinder  61 ,  62  is crimped onto the end of the cord  41 ,  42 ,  43 ,  44 . Many other means of attaching the tilt cords  41 ,  42 ,  43 ,  44 .to the tilt tube  29  are possible. 
         [0038]    Ladderbraid is a cord that is normally responsible for controlling the angle of the slats  2  in a venetian blind. Ladderbraid looks somewhat like a ladder. It consists of two main tilt cords  41 ,  42 ,  43 ,  44  and a plurality of cross-members that connect the two tilt cords  41 ,  42 ,  43 ,  44 . Each slat  2  of the blind normally rests on a separate cross-member of the ladderbraid. 
         [0039]    Ladderbraid is used in the preferred embodiment because the preferred embodiment describes a venetian blind, and ladderbraid is commonly used in venetian blinds. However, many other types of cord, or linkages can be employed to control the angle of the slats. For example in a vertical blind the slats are commonly hung from rotating piece. The angle of the rotating piece is commonly driven with cords or chain-type linkages. In cloth blinds such as those that suspend fabric slats between two sheer fabric facings, the sheer fabric facings perform the same function as the ladderbraid and tilt cords. 
         [0040]    Tilt cords  41 ,  42 ,  43 ,  44  are discussed throughout the preferred embodiment. However, a tilt cord is any of many types of connecting devices. This could include, but is not limited to belts, chains, straps, tapes, webbing, direct linkages, rods, connector pieces, cloth sheets, etc. The tilt cords  41 ,  42 ,  43 ,  44  could be solid pieces, or flexible pieces, or a combination of the two. Many configurations are possible. 
         [0041]    The angle of the slats  2  is controlled by lifting one of the tilt cords  41 ,  42 ,  43 ,  44  higher than the other tilt cord  41 ,  42 ,  43 ,  44 . Venetian blinds typically have two or more ladderbraids. Many blinds have just two ladderbraids - one at each end of the blind. However, wider windows often have additional ladderbraids interposed between the ladderbraids at each end. Each of the ladderbraids normally runs vertically from the headrail  1  down to the bottomrail  3  of the blind. To describe the routing of the tilt cords of the ladderbraid, the description will begin at the bottom of the blind and work up to the top. 
         [0042]    The end of the first tilt cord  41 ,  43  is attached to the front edge of the bottomrail  3 . The second tilt cord  42 ,  44  is attached to the opposite side of the bottomrail  3 . The ladderbraid extends vertically up from the bottomrail  3 . A plurality of cross-members connects two tilt cords  41 ,  42   43 ,  44 . One slat is placed upon each cross-member, up to the headrail  1 . Next, the tilt cords  41 ,  42 ,  43 ,  44  are routed through holes  70 ,  71  in the bottom of the headrail  1 . There is one hole for each of the ladderbraid&#39;s tilt cords  70 ,  71 . The ladderbraid is then routed and mechanically connected to the tilt tube  29 . 
         [0043]    In this embodiment both tilt cords  41 ,  42 ,  43 ,  44  are attached to the tilt tube  29 . They are routed so that each tilt cord  41 ,  42 ,  43 ,  44  makes initial contact with the tilt tube  29  on opposite sides of the tilt tube  29 . They are also attached to the tilt tube  29 . The spinning tilt tube  29  causes one of the tilt cords  41 ,  42 ,  43 ,  44  to wind around the tilt tube  29  while the other tilt cord  41 ,  42 ,  43 ,  44  simultaneously unwinds. The effect of driving the second motor  20  is to cause the slats  2  of the blind to tilt. It is also possible to connect only one of the tilt cords  41 ,  42 ,  43 ,  44  to the tilt tube  29  and still achieve the tilting operation. In the preferred embodiment, the tilt cords  41 ,  42 ,  43 ,  44  are attached to the tilt tube  29  using the same method that is used to attach the lift cords  32 ,  33 ,  90  to the lift tube  28 . 
         [0044]    Methods of routing the tilt cords  41 ,  42 ,  43 ,  44  and lift cords  32 ,  33 ,  90  are employed to ensure that the lift cords  32 ,  33 ,  90  and tilt cords  41 ,  42 ,  43 ,  44  don&#39;t interfere and tangle with each other. For aesthetic reasons it is common practice in venetian blinds to have the tilt cords  41 ,  42 ,  43 ,  44  and lift cords  32 ,  33 ,  90  rise vertically across the slats  2  at substantially the same position along the length of the slats  2 . As a result, the tilt cords  41 ,  42 ,  43 ,  44  and lift cords  32 ,  33 ,  90  typically enter the headrail  1  at substantially the same position along the length of the headrail  1 . So that there is an available path for all of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44 , a routing method is provided. There are four different routed methods described to provide a path for each of the tilt cords  41 ,  42 ,  43 ,  44  and lift cords  32 ,  33 ,  90 . The first method is to divert some of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  out of the path of the other cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44 . The second method is to route cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  at an angle such that they don&#39;t contact the other cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44 . The third method involves offsetting the holes  50 ,  70 ,  71 ,  72  for the lift cords  32 ,  33 ,  90  and tilt cords  41 ,  42 ,  43 ,  44  so that they don&#39;t interfere with each other. The fourth method is to route each of the cords from one tube, around opposite sides of the opposite tube. More details on each of these four methods are described below. A few examples of these routing methods are illustrated in  FIG. 7-17  that show a few of the many possible embodiments of these methods. 
         [0045]    One method of creating a free, unobstructed routing path for the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  is to divert some of the cords or all of the cords,  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  of the group the tilt cords  41 ,  42 ,  43 ,  44  and lift cords  32 ,  33 ,  90  into an unobstructed path by routing them out of the obstructed path by creating a path that routes one or a plurality of the cords  31 ,  32 ,  90 ,  41 ,  42 ,  43 ,  44  around a diverting object  60 ,  66 , such as a pulley or a non-rotating object that the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  can slide across. Many embodiments of this method are possible. However, two embodiments of this method are shown in  FIG. 7 ,  8 ,  9 , and  10 .  FIG. 7 and 8  are two illustrations of the same configuration from two different perspectives that illustrate a configuration that employs a single lift cord  32 ,  33  per lift point. In these  FIG. 7 and 8  one of the tilt cords  41 ,  43  is routed out of the obstructed path and around a diverting object  60 , creating a free path for all of the cords  32 ,  33 ,  42 ,  44 .  FIG. 9 and 10  are two illustrations of one configuration from two different perspectives that employ the dual-lift-cord-per-lift-point method. In this embodiment one of the lift cords  32 ,  33  is routed out of the obstructed path and around a diverting object  66 . 
         [0046]    Routing the cords,  32 ,  33 ,  41 ,  42 ,  43 ,  44  of the group of tilt cords  41 ,  42 ,  43 ,  44 , and lift cords  41 ,  42 ,  43 ,  44  at an angle that is not perpendicular to the length of the headrail  1  provides another method of creating an unobstructed path. There are many different possible embodiments of this method. One embodiment of this method is illustrated in  FIG. 11 and 12 .  FIG. 11 and 12  are two illustrations of the same configuration from two different perspectives. In  FIG. 1 and 12  one of the tilt cords  41 ,  43  is routed at an angle so that it doesn&#39;t interfere with the other tilt cord  42 ,  44 , or the lift cord  32 ,  33 . 
         [0047]    If some of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  within the group, the group consisting of lift cords  32 ,  33 ,  90  and tilt cords  41 ,  42 ,  43 ,  44 , enter the headrail  1  at a position along the length of the headrail  1  that is different from the point where other cords within the group enter the headrail  1  an unobstructed path for all of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  can be created. 
         [0048]      FIG. 13 ,  14 ,  15 , and  16  show two different configurations that employ this method.  FIG. 13 and 14  are two illustrations of the same configuration from two different perspectives that show routing implementations where the lift cord hole  50  is at a different position along the length of the headrail than the ladderbraid holes  70 ,  71 . The configuration in  FIG. 13 and 14  employs a single lift cord  32 ,  33  per lift point.  FIG. 15 and 16  show a dual-lift-cord-per-lift-point configuration.  FIG. 15 and 16  are two illustrations of the same configuration from two different perspectives. In  FIG. 15 and 16  one of the lift cord holes  72  is at a different position along the length of the headrail than the other lift cord hole  50  and the tilt cord holes  70   71 .  FIG. 13 ,  14 ,  15 , and  16  illustrate just two different configurations that employ this method. There are many possible configurations that can employ this method to create an unobstructed path for all of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44 . 
         [0049]    Another method to achieve an unobstructed routing path for the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44  is to route each of the cords from one tube, around opposite sides of the opposite tube. For example, this could be accomplished by routing one tilt cord  41 ,  42 ,  43 ,  44  around one side of the lift tube, and routing the other tilt cord around the other side of the lift tube. Likewise this could be accomplished by routing one lift cord around one side of the tilt tube, and routing the other lift cord around the other side of the tilt tube. This method can be employed to create an unobstructed routing path for all of the cords. 
         [0050]    There are many possible embodiments of this method. One embodiment of this method is shown in  FIG. 17 . In this embodiment the tilt cords  41 ,  42 ,  43 ,  44  are routed directly from the holes  70 ,  71  in the bottom of the headrail  1  to the tilt tube  29 . In this embodiment one of the lift cords  32 ,  33  is routed directly to the lift tube  28 . The other lift cord  90  is routed from the hole  50  in the bottom of the headrail  1 , then around the tilt tube  29 , and to the lift tube  28 . The result is an unobstructed path for all of the cords  32 ,  33 ,  90 ,  41 ,  42 ,  43 ,  44 . 
         [0051]    A logic control unit  45  is used to coordinate the operation of the blind. Many embodiments of this logic control unit  45  are possible. The preferred embodiment uses a switch  52  as the input device. Many other types of input devices are possible which would include, but not be limited to: magnetic switches, proximity sensing switches, remote control, thermal switches, light sensors, solid states switches, relay switching. Although many types of switches could be used, the preferred embodiment uses a single single-pole, double-throw momentary contact switch  52  that is mounted vertically such that there is an “up” contact that is in the higher vertical position and a “down” contact that is in the lower vertical position. The logic control unit  45  can be configured many different ways to support a variety of different logical blind functions. However, for the preferred embodiment the functionality is divided into 5 basic operations as described below. 
         [0052]    Operation 1: Pressing and holding the up contact causes slats  2  to tilt forward. Operation 1 is terminated when the up contact is released or when the angle of the slats  2  reach a completely vertical (closed) position 
         [0053]    Operation 2: Pressing and holding the down contact causes slats  2  to tilt backward. Operation 2 is terminated when the down contact is released or when the angle of the slats  2  reaches a completely vertical (closed) position. 
         [0054]    Operation 3: Pressing the up contact momentarily causes the slats  2  to first rotate into a horizontal angular position, then all the slats  2  are lifted to the top. Operation  3  is terminated when the up or down contact is momentarily pressed, or when the operation is complete. The operation completes when the slats  2  are at a horizontal (open) angle and the blind has reached the fully-raised position. 
         [0055]    Operation 4: Pressing the down contact momentarily causes the slats  2  to first be dropped to their lowered-most position, then the slats  2  are rotated to a horizontal angular position. Operation 4 is terminated when the up or down contact is momentarily pressed, or when the operation is complete. The operation is complete when the when blind has reached the fully-lowered position and slats  2  reach a horizontal (open) angle. 
         [0056]    Operation 5: Tapping the down contact twice in quick succession causes the slats  2  to be dropped to their fully lowered position. Operation 5 doesn&#39;t change the angle of the slats  2 . Operation 5 is terminated when the up or down contact is momentarily pressed, or when the blind has reached the fully-lowered position. 
         [0057]    A state diagram that shows the states of the preferred embodiment of the logic control unit is shown in  FIG. 5 . 
         [0058]      FIG. 6  shows a circuit diagram of the logic control unit  45  for the preferred embodiment. The logic control unit  45  is responsible for switching the motors  28 ,  29  on and off to drive the appropriate functions of the blind. The logic control unit  45  consists of a power supply  46 , a microcontroller  47 , and four relays  48 ,  49 ,  50 ,  5   1 . The power supply  46  converts the AC input voltage to a DC voltage that can power the microcontroller  47  and relays  48 ,  49 ,  50 ,  5   1 . A single-pole, double-pole momentary contact switch  52  is provided. The switch  52  provides inputs to a microcontroller  47 , which performs the logic control functions. In this embodiment two of the I/O pins  91 ,  92  on the microcontroller  47  are defined as inputs. The two defined inputs  91 ,  92  have internal pull-up resistors that maintain a “high” on the input until they are pulled low by depressing the switch  52 . Depressing the switch  52  in either direction causes the microcontroller  47  to read a “low” on the respective input. The microcontroller reads the signals from the switch  52  and determines the appropriate action to take using logic defined in the program. However, the program is first responsible for de-bouncing the switch; this is accomplished by waiting a short period of time (about 10 ms) after an input is read before any other inputs can be recognized. 
         [0059]    The four outputs of the microcontroller  47  are connected to each of the four relays  48 ,  49 ,  50 ,  51 : the first relay  49  enables driving the lift motor  19  clockwise, the second relay  48  enables driving the lift motor  19  counterclockwise, the third relay  51  enables driving the tilt motor  20  clockwise, the fourth relay  50  enables driving the tilt motor  20  counterclockwise. The embodiment of the present invention employs an Atmel AVR microcontroller  47 . The Atmel AVR microcontrollers  47  have sufficient power to directly drive Tyco V23079A relays  48 ,  49 ,  50 ,  51 . The Tyco V23079A relays  48 ,  49 ,  50 ,  51  are selected because they can be driven with just 28 mA, which is within the capabilities of the Atmel AVR 2313 microcontroller  47 . These Tyco V23079A relays  48 ,  49 ,  50 ,  51  can switch a  5 A load, more than enough for the motors  19 ,  20 . 
         [0060]    In the preferred embodiment, the logic control unit  45  is mounted within the headrail  1 . It is mounted to one of the motor mounts  12 . However, for safety, the logic control unit  45  is encased in a fire-resistant electrical box.