Abstract:
A lift cord assembly for a Venetian blind includes a first rotating member for connection of two ladder strings, and a second rotating member rotated synchronously with the first rotating member for connection of a single lift cord. By this design, the first rotating member and the second rotating member can be forced to rotate synchronously by the actuation of the lift cord, enabling the ladder strings to be wound around the first rotating member to fold slats of the Venetian blind. As a result, the ladder strings can be integrated by the lift cord assembly of the present invention into the lift cord so as to attain the purposing of enhancing safety of children in the household.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to a Venetian blind, and more specifically to a lift cord assembly for a Venetian blind, which can protect safety of children in the household. 
         [0003]    2. Description of the Related Art 
         [0004]      FIG. 1  shows a conventional Venetian blind  10 , comprising an upper rail  11 , a lower rail  12 , a plurality of slats  13  arranged between the upper rail  11  and the lower rail  12 , and two ladder strings  14  passing through the slats  13  and having a bottom end connected with the lower rail  12  and a top end suspended from the upper rail  11  through a stopper  15  mounted in the upper rail  11 . Therefore, when the suspending portions  142  of the ladder strings  14  are pulled simultaneously, the lower rail  12  can be gradually raised to fold the slats  13 . 
         [0005]    According to different needs, the slat  13  will be designed to increase its width such that the number of the ladder strings  14  has to be added in order to enable the widened slats  13  to be folded and unfolded smoothly and balancedly. However, if the ladder strings  14  are too numerous, the ladder strings  14  will have too many suspending portions  142 , causing children playing around the conventional Venetian blind  10  to be easily get caught by them. Thus, the conventional Venetian blind  10  has a potential danger to children in the household. 
       SUMMARY OF THE INVENTION 
       [0006]    It is one objective of the present invention to provide a lift cord assembly for a Venetian blind, which can prevent children from getting caught therein to protect the safety of the household. 
         [0007]    To achieve this objective of the present invention, the lift cord assembly provided by the present invention comprises a base for being mounted in an upper rail of the Venetian blind, a first rotating member rotatably mounted with the base for connection of top ends of ladder strings of the Venetian blind, a second rotating member rotatably mounted with the base and synchronously rotated with the first rotating member, and a lift cord having one end connected with the second rotating member and the other end for being suspended from the upper rail. When a user pulls a suspending portion of the lift cord, the second rotating member is driven to rotate, and then the first rotating member is rotated synchronously through the rotation of the second rotating member. Thus, the ladder strings can be wound around the first rotating member through the rotation of the first rotating member to fold slats of the Venetian blind. 
         [0008]    By the aforesaid design, no matter how many ladder strings are provided, the ladder strings can be integrated by the lift cord assembly of the present invention into one single lift cord so as to prevent children from getting caught by the lift cord and therefore enhance the safety of the household. 
         [0009]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0011]      FIG. 1  is a plan view of a Venetian blind according to a prior art; 
           [0012]      FIG. 2  is a perspective view of a Venetian blind in which a lift cord assembly according to a first embodiment of the prevent invention is installed; 
           [0013]      FIG. 3  is an exploded view of the lift cord assembly according to the first embodiment of the prevent invention, in which the lift cord is removed for concise illustration purpose; 
           [0014]      FIG. 4  is a top view of  FIG. 2 ; 
           [0015]      FIG. 5  is a plan view of a part of the Venetian blind, showing the slats are unfolded; 
           [0016]      FIG. 6  is similar to  FIG. 5 , but showing the slats are folded; 
           [0017]      FIG. 7  is an exploded view of the lift cord assembly according to a second embodiment of the prevent invention, in which the lift cord is removed for concise illustration purpose; 
           [0018]      FIG. 8  is a top view of a Venetian blind equipped with the lift cord assembly according to the second embodiment of the prevent invention; 
           [0019]      FIG. 9  is an enlarged view of  FIG. 8 , showing the lift cord assembly according to the second embodiment of the prevent invention; 
           [0020]      FIG. 10  is a plan view of a part of the Venetian blind equipped with the lift cord assembly of the second embodiment, showing the slats are unfolded; 
           [0021]      FIG. 11  is similar to  FIG. 10 , but showing the slats are folded; 
           [0022]      FIG. 12  is an exploded view of the lift cord assembly according to a third embodiment of the prevent invention, in which the lift cord is removed for concise illustration purpose; 
           [0023]      FIG. 13  is a top view of a Venetian blind equipped with the lift cord assembly according to the third embodiment of the prevent invention; 
           [0024]      FIG. 14  is an enlarged view of  FIG. 13 , showing the lift cord assembly according to the third embodiment of the prevent invention; 
           [0025]      FIG. 15  is a plan view of a part of the Venetian blind equipped with the lift cord assembly of the third embodiment, showing the slats are unfolded; and 
           [0026]      FIG. 16  is similar to  FIG. 15 , but showing the slats are folded. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    As shown in  FIG. 2 , a lift cord assembly  30  in accordance with a first embodiment of the present invention is installed in a Venetian blind  20 . In this embodiment, the Venetian blind  20  includes an upper rail  21 , a lower rail  22 , a plurality of slats  23  arranged between the upper rail  21  and the lower rail  22 , and two ladder strings  24  each passing through the slats  23 , having a bottom end connected with the lower rail  22  and a top end received in the upper rail  21 , and having a rectangular cross-section. The lift cord assembly  30  according to the first embodiment of the present invention comprises a base  31 , a first rotating member  32 , a second rotating member  33 , and a lift cord  34 . 
         [0028]    The base  31  is a hollow and rectangular box, and mounted in the upper rail  21  of the Venetian blind  20 . 
         [0029]    The first rotating member  32  is rotatably connected between two opposite sides of the base  31 , having a first rod  322  for connection of the top ends of the ladder strings  24 , a first spur gear  324  connected with one end of the first rod  322 , and two first wheels  326  and  328 , one of which is connected with the other end of the first rod  322 , and the other of which is connected with a middle of the first rod  322  to divide the ladder strings  24  from each other. 
         [0030]    The second rotating member  33  is rotatably connected between two opposite sides of the base  31 , having a second rod  332  parallel to the first rod  322 , a second wheel  334  connected with one end of the second rod  332 , and a second spur gear  336  connected with the other end of the second rod  332  and engaged with the first spur gear  324 . 
         [0031]    The lift cord  34  has a circular cross-section, and has one end connected with the second rod  332  of the second rotating member  33 , and the other end suspending from the upper rail  21  through a stopper  25  mounted in the upper rail  21 , as shown in  FIG. 5 . 
         [0032]    When the suspending portion of the lift cord  34  is pulled by an external force, as shown in  FIGS. 3 and 6 , the second rotating member  33  is driven to rotate by the lift cord  34 , and then the first rotating member  32  is rotated synchronously by the second rotating member  33  through the engagement between the second spur gear  336  and the first spur gear  324 . During the rotation of the first rotating member  32 , the ladder strings  24  can be wound around the first rod  322  of the first rotating member  32  to gradually fold the slats  23 . 
         [0033]      FIGS. 7 to 9  show a lift cord assembly  40  in accordance with a second embodiment of the present invention, comprising a base  41 , a first rotating member  42 , a second rotating member  43 , a third rotating member  44 , and a lift cord  45 . 
         [0034]    The base  41  includes two opposite lateral plates  414 , a bottom plate  412  connected between the lateral plates  414 , two support portions  416  protruding from a top surface of the bottom plate  412  and each having a concavity  418  at a top end thereof. 
         [0035]    The first rotating member  42  includes a first rod  422  rotatably placed on the concavities  418  of the support portions  416  of the base  41 , two first reels  424  respectively connected with two ends of the first rod  422  for connection of the top ends of the ladder strings  24 , and two spur gear  426  respectively connected with the first rod  422  at locations near two ends of the first rod  422  and spaced a distance from the adjacent first reel  424 . 
         [0036]    The second rotating member  43  is rotatably connected between the support portions  416  of the base  41 , having a second rod  432  for connection of the lift cord  45  and two second spur gears  434  respectively connected with two ends of the second rod  432  and engaged with the adjacent first spur gear  426 . 
         [0037]    The third rotating member  44  is rotatably connected between the support portions  416  of the base  41 , having a third rod  441  and two third spur gears  443  respectively connected with two ends of the third rod  441  and engaged with the adjacent first spur gear  426  and the adjacent second spur gear  434 . 
         [0038]    By this way, when the suspending portion of the lift cord  45  is pulled by the external force, as shown in  FIGS. 9 to 11 , the second rotating member  43  is driven to rotate by the lift cord  45 , and then the first rotating member  42  is rotated synchronously by the second rotating member  43  through the engagement between the second spur gears  434  and the first spur gears  426 , and meanwhile the third rotating member  44  is rotated synchronously through the engagement among the second spur gears  434 , the first spur gears  426 , and the third spur gears  443 . Thereafter, the ladder strings  24  can be wound around the first reels  424  of the first rotating member  42  during the rotation of the first rotating member  42  to gradually fold the slats  23 . 
         [0039]      FIGS. 12 to 14  show a lift cord assembly  50  in accordance with a third embodiment of the present invention, comprising a base  51 , a first rotating member  52 , a second rotating member  53 , and a lift cord  54 . 
         [0040]    The base  51  includes an upper base body  511  having two opposite curved notches  514  at a top surface thereof and two slots  515  each formed at a periphery of one of the curved notches  514 , a lower base body  512  fastened to a bottom side of the upper base body  511  and provided with a post  516  protruding from a top surface thereof, and two covers  513  spacedly fastened to a top side of the upper base body  511 . 
         [0041]    The first rotating member  52  includes two first reels  522  for connection of the top ends of the ladder strings  24 , and two first bevel gears  524  each having a teeth portion  525  and a shaft portion  526  connected between the teeth portion  525  and the first reel  522  and provided with a protrusion  527  at an outer periphery thereof inserted into one of the slots  515  of the upper base body  511 , such that the two first bevel gear  524  of the first rotating member  52  are rotatably and oppositely mounted on the top side of the upper base body  511  and covered by the covers  513 . 
         [0042]    The second rotating member  53  includes a second reel  532  having a bottom side inserted by the post  516  of the lower base body  512  and connected with one end of the lift cord  54  such that the second reel  532  can be pulled to rotate by the lift cord  54 , and a second bevel gear  534  connected with a top side of the second reel  532  and engaged with the first bevel gears  524  such that the first rotating member  52  can be driven to rotate through the rotation of the second reel  532 . 
         [0043]    When the suspending portion of the lift cord  54  is pulled by the external force, as shown in  FIGS. 12 , and  14  to  16 , the second rotating member  53  is driven to rotate by the lift cord  54 , and then the first reels  522  are driven to rotate synchronously by the second rotating member  43  through the engagement between the second bevel gear  534  and the first bevel gears  524 , and meanwhile the ladder strings  24  can be wound around the first reels  522  of the first rotating member  52  during the rotation of the first reels  522  so as to gradually fold the slats  23 . 
         [0044]    Accordingly, even though the number of the ladder string is added in order to cooperate with the widened slat, the lift cord assembly of the present invention can be used to integrate all of the ladder strings into one suspending lift cord for preventing children from getting caught by the lift cord and enhancing the safety of the household. 
         [0045]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.