Patent Publication Number: US-2015059992-A1

Title: Damper unit for Roller Blind

Description:
BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to a roller blind and, more particularly, to a damper unit for a roller blind. 
     2. Related Prior Art 
     As disclosed in Taiwanese Patent Publication Nos. 174404 and 481217, a conventional roller blind includes a web wound on a roller supported on a frame secured to a wall. Generally, a weight in the form of a rod, tube or blade is tied to an edge of the web while an opposite edge of the web is tied to the roller. The roller is rotated in a direction to release the web from the roller. The web is spread neatly by the weight. The roller is rotated in an opposite direction to withdrawn the web onto the roller. It requires an adequate force to withdrawn the web onto the roller because of the weight. However, an excessive force is often used to withdraw the web onto the roller because an insufficient does not withdraw the web onto the roller at all. Such an excessive force causes the weight to bump the frame and make loud noise, and this is annoying and dangerous. 
     Therefore, the present invention is intended to obviate or at least alleviate the problems encountered in prior art. 
     SUMMARY OF INVENTION 
     It is the primary objective of the present invention to provide a roller blind which is operable nicely and quietly. 
     To achieve the foregoing objective, the roller blind includes a roller, a web wound on the roller, and a damper unit for damping the rotation of the roller. The damper unit includes a cylinder, an axle and a damper. The cylinder is inserted in the roller so that they are rotatable together. The axle is inserted in the cylinder so that the cylinder is rotatable on the axle. The damper is provided between the cylinder and the axle to damp the rotation or the cylinder on the axle. 
     Other objectives, advantages and features of the present invention will be apparent from the following description referring to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present invention will be described via detailed illustration of three embodiments referring to the drawings wherein: 
         FIG. 1  is a perspective view of a roller blind according to the first embodiment of the present invention; 
         FIG. 2  is an exploded view of the roller blind shown in  FIG. 1 ; 
         FIG. 3  is a partial, perspective view of a cylinder of the roller blind shown in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of the roller blind shown in  FIG. 1 ; 
         FIG. 5  is another cross-sectional view of the roller blind taken along a line A-A shown in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of the roller blind in another position than shown in  FIG. 5 ; 
         FIG. 7  is a cross-sectional view of the roller blind in another position than shown in  FIG. 4 ; 
         FIG. 8  is a cross-sectional view of the roller blind in another position than shown in  FIG. 7 ; 
         FIG. 9  is a cross-sectional view of a roller blind according to the second embodiment of the present invention; 
         FIG. 10  is a cross-sectional view of the roller blind in another position than shown in  FIG. 9 ; 
         FIG. 11  is an exploded view of a roller blind according to the third embodiment of the present invention; 
         FIG. 12  is a perspective view of a disc of the roller blind shown in  FIG. 11 ; and 
         FIG. 13  is a cross-sectional view of the roller blind shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 through 8 , there is a roller blind  10  according to a first embodiment of the present invention. The roller blind  10  includes web  12  wound on a roller  11  supported on a frame (not shown) secured to a wall (not shown). An edge of the web  12  is connected to the roller  11  while a weight (not numbered) in the form of a rod, tube or blade is tied to an opposite edge of the web  12 . Referring to  FIG. 7 , the roller  11  is rotated in a first direction to release the web  12  from the roller  11 . The web  12  is spread neatly by the weight. Referring to  FIG. 8 , the roller  11  is rotated in a second direction to withdrawn the web  12  onto the roller  11 . An excessive force is often used to withdraw the web  12  onto the roller  11  since an insufficient does not withdraw the web onto the roller at all. The roller blind  10  further includes a damper unit  20  for damping the withdrawal of the web  12  onto the roller  11  to prevent such an excessive force from causing the weight to bump the frame and make loud noise. 
     Referring to  FIGS. 2 and 3 , the damper unit  20  includes a damper  22 , a cylinder  30 , an axle  40 , a lock  60  and a rod  70 . The damper  22  is a helical spring that includes two radial ends  24  and  26  extending perpendicular to an axis about which the helical spring extends. 
     The cylinder  30  includes two ends  37  and  38 , a circular aperture  31  in the end  37 , a polygonal aperture  32  in the end  38 , three slots  34 ,  35  and  36  in the periphery, and ribs  33  on the periphery. The end  37  is made with an external diameter larger than that of the end  38 . The slot  34  extends longitudinally while the slots  35  and  36  extend transversely. The slot  34  extends to the slot  35  from the slot  36 . Thus, the slots  34 ,  35  and  36  together become a Z-shaped opening 
     The rod  70  is formed with a polygonal section  72  and a threaded section  71 . The polygonal section  72  is made corresponding to the polygonal aperture  32 . 
     The axle  40  includes two sections  41  and  50 , a screw hole  43  in the section  41 , and a flat cavity  42  in the section  50 , and blocks  49  on an external side of the section  50 . The section  50  is made with an external diameter larger than that of the section  41 , thus forming a shoulder  44  between the sections  41  and  50 . The screw hole  43  is made corresponding to the threaded section  71 . 
     The lock  60  is substantially made corresponding to the flat cavity  42 . However, the lock  60  includes two groups of ratchets  61 . Each group of ratchets  61  is arranged along a corresponding edge of the lock  60 . 
     Referring to  FIG. 4 , a section of the lock  60  is inserted in the flat cavity  42  of the axle  40  while an opposite section of the lock  60  is secured to the frame of the roller blind  10 . Thus, the axle  40  and the lock  60  are not rotatable relative to the frame of the roller blind  10 . The groups of ratchets  61  enable easy insertion of the lock  60  into the flat cavity  42 . However, in an attempt to pull the lock  60  from the flat cavity  42 , the groups of ratchets  61  bite the wall of the cavity  42  and keep the lock  60  in the flat cavity  42 . 
     The section  41  of the axle  40  is inserted in the damper  22 . The damper  22  is allowed to rotate on the section  41  of the axle  40 . 
     The threaded section  71  of the rod  70  is inserted in the screw hole  43  of the axle  40 . Thus, the rotation of the rod  70  relative to the axle  40  causes rectilinear movement of the rod  70  relative to the axle  40 . 
     The polygonal section  72  of the rod  70  is inserted in the polygonal aperture  32  of the cylinder  30  while the axle  40  and the damper  22  are placed in the cylinder  30 . The radial ends  24  and  26  of the damper  22  are inserted in the slots  35  and  36 , respectively. The blocks  49  are placed in the circular aperture  31 . The cylinder  30  is allowed to smoothly rotate on the axle  40  due to a small total area of contact of the wall of the circular aperture  31  with the blocks  49 . The cylinder  30  is fit in the roller  11  so that they are rotatable together. 
     Referring to  FIG. 7 , the roller  11  is rotated in the first direction to release the web  12  from the roller  11 . The cylinder  30  and the rod  70  are rotated in the first direction relative to the axle  40 . The rotation of the rod  70  in the first direction causes rectilinear movement of the rod  70  into a position shown in  FIG. 6  from a position shown in  FIG. 5  because of the insertion of the threaded section  71  of the rod  70  in the screw hole  43  of the axle  40 . 
     The radial end  26  of the damper  22  is pressed by the cylinder  30  so that the damper  22  is rotated on the axle  40 . The friction between the damper  22  and the axle  40  damps the rotation of the cylinder  30  and the roller  11 . 
     Referring to  FIG. 8 , the roller  11  is rotated in the second direction to withdraw the web  12  onto the roller  11 . Accordingly, the cylinder  30  and the rod  70  are rotated in the second direction relative to the axle  40 . The rotation of the rod  70  in the second direction causes rectilinear movement of the rod  70  into the position shown in  FIG. 5  from the position shown in  FIG. 6  due to the insertion of the threaded section  71  of the rod  70  in the screw hole  43  of the axle  40 . 
     The radial end  24  of the damper  22  is pressed by the cylinder  30  so that the damper  22  is rotated on the axle  40 . The friction between the damper  22  and the axle  40  damps the rotation of the cylinder  30  and the roller  11 . 
     The threaded section  71  reaches a closed end of the screw hole  43  to avoid further rotation of the rod  70  relative to the axle  40  in the second direction. The extent to which the web  12  can be withdrawn onto the roller  11  is adjustable by changing the depth of the threaded section  71  in the screw hole  43  when the web  12  is substantially completely released from the roller  11 . The web  12  can be withdrawn onto the roller  11  to a relatively small extent if the threaded section  71  is relatively deep in the screw hole  43  when the web  12  is substantially completely released from the roller  11 . The web  12  can be withdrawn onto the roller  11  to a relatively large extent if the threaded section  71  is relatively shallow in the screw hole  43  when the web  12  is substantially completely released from the roller  11 . 
     Referring to  FIGS. 9 and 10 , there is a roller blind according to a second embodiment of the present invention. The second embodiment is like the first embodiment except four things. At first, the axle  40  includes a screw hole  46  instead of the flat cavity  42 . Secondly, there is additionally a plug  47 . The plug  47  includes a threaded section  45  inserted in the screw hole  46 . The flat cavity  42  is made in the plug  47  instead of the axle  40 . Thirdly, there is a ball  48  to keep the threaded section  71  from the plug  47  and hence avoid deadlock of the threaded section  71  to the plug  47 . Fourthly, there is an auxiliary damper  80 . The auxiliary damper  80  includes a spring  81 , a ring  82 , a washer  83  and a screw  84 . The ring  82  is placed on the polygonal section  72  of the rod  70  and against the end  38  of the cylinder  30 . The screw  84  is used to secure the washer  83  to the tip of the polygonal section  72 . The spring  81  is compressed between the ring  82  and the washer  83 . Thus, the threaded section  71  of the rod  70  is tighter in the screw hole  43  according to the second embodiment than the first embodiment, and the damping is better according to the second embodiment than the first embodiment. 
     Referring to  FIGS. 11 through 13 , there is a roller blind according to a third embodiment of the present invention. The third embodiment is like the second embodiment except several things. At first, a clip  90  is used instead of the washer  83  and the screw  84 . The clip  90  includes an aperture  91  made therein axially, a conical frustum  93  formed around the aperture  91 , and slits  92  made in the conical frustum  93  in a radial manner. Secondly, the rod  70  includes a circular section  85  extending from the polygonal section  72 . The aperture  91  is made with a diameter smaller than that of the circular section  85 . The aperture  91  and the slits  92  are enlarged as the clip  90  is forced onto the circular section  85  in a direction. The clip  90  tends to close and lock itself onto the circular section  85 . 
     The present invention has been described via the detailed illustration of the embodiments. Those skilled in the art can derive variations from the embodiments without departing from the scope of the present invention. Therefore, the embodiments shall not limit the scope of the present invention defined in the claims.