Patent Publication Number: US-RE37143-E

Title: Slat angle adjusting device for a venetian blind

Description:
FIELD OF THE INVENTION 
     The present invention relates to an angle adjusting device, and more particularly to a slat angle adjusting device for a Venetian blind. 
     BACKGROUND OF THE INVENTION 
     A conventional slat angle adjusting device for a Venetian blind is shown in FIG. 5, however, there still remain shortcomings therein. There will be a complete illustration in the detailed description of the preferred embodiments, concerning the conventional adjusting device. 
     The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional device. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, there is provided a slat angle adjusting device for a Venetian blind and comprising a first casing and a second casing coupled with each other. 
     A pinion is rotatably mounted between the first and second casings. A worm is rotatably mounted between the first and second casings and meshes with the pinion. A driven gear is fixedly mounted on one end of the worm. A drive gear is rotatably mounted between the first and second casings and meshes with the driven gear. A drive axle is formed on one end of the drive gear and extends outward of the first and second casings. 
     A bracket includes a first end portion engaged with the first and second casings, and a second end portion having two side walls extending upwardly therefrom. A roller is fixedly mounted on the drive axle and is rotatably received between the two side walls of the bracket. 
    
    
     Further features of the present invention will become apparent from a careful reading of the detailed description provided hereinbelow, with appropriate reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a slat angle adjusting device for a Venetian blind in accordance with the present invention; 
     FIG. 2 is an exploded view of FIG. 1; 
     FIG. 3 is a front plan cross-sectional view of FIG. 1, showing the adjusting device being received in a headrail of the Venetian blind; 
     FIG. 4 is a partially cross-sectional side view of FIG. 1; and 
     FIG. 5 is an exploded view of a conventional slat angle adjusting device for a Venetian blind in accordance with the prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For a better understanding of the present invention, reference is made to FIG. 5 illustrating a conventional slat angle adjusting device for a Venetian blind (not shown) in accordance with the prior art. 
     The conventional slat angle adjusting device comprises a first casing  72  and a second casing  74  coupled together with each other and received in a substantially U-shaped headrail (not shown) of the Venetian blind. 
     A tilt rod (not shown) is longitudinally disposed in the headrail and extends through the first and second casings  72  and  74 . A pinion  78  is rotatably received between the first and second casings  72  and  74  and is fixedly mounted around the tilt rod. 
     A worm  76  located beneath the pinion  78  is rotatably mounted between the first and second casings  72  and  74  and meshes with the pinion  78 . A drive shaft  762  square in cross-section is formed on one end portion of the worm  76 . A pulley  80  is rotatably received between the first and second casings  72  and  74  and is fixedly mounted around the drive shaft  762 . A tilt cord (not shown) winds around the pulley  80  and has two distal ends extending downwardly. 
     In operation, a user can exert a drawing force on the two distal ends of the tilt cord, thereby rotating the pulley  80  which can drive the drive shaft  762  to rotate the worm  76  which can in turn rotate the pinion  78  so as to rotate the tilt rod, thereby adjusting a rotational angle of a plurality of slats (not shown) of the Venetian blind. 
     By such an arrangement, the worm  76  together with the drive shaft  762  is driven by means of the drawing force of the tilt cord so as to rotate the tilt rod via the pinion  78 , thereby rotating the plurality of slats. 
     However, the user has to exert a large force on the tilt cord so as to rotate the plurality of slats via a transmission of the worm  76  and the pinion  78  when the plurality of slats are made of a heavy material such as wood and the like, thereby greatly causing an inconvenience in operation. 
     Referring to the remaining drawings, and initially to FIGS. 1-3, a slat angle adjusting device  10  in accordance with the present invention is provided for adjusting a rotational angle of a plurality of slats (not shown) of a Venetian blind  40 . The Venetian blind  40  comprises a headrail  42  substantially U-shaped in section with two side walls each having a hook portion  422  extending inwardly and downwardly therefrom. 
     The slat angle adjusting device  10  comprises a first casing  12  and a second casing  14  received in the headrail  42  and coupled with each other. The first and second casings  12  and  14  respectively have an abutting edge  122  and  142  on each of which an associated hook portion  422  of the headrail  42  is securely rested respectively. 
     A pinion  18  is rotatably mounted between the first and second casings  12  and  14 . A tilt rod  46  is fixedly mounted in and driven by the pinion  18  for adjusting a rotational angle of the plurality of slats of the Venetian blind  40 . 
     A worm  16  located beneath the pinion  18  is rotatably mounted between the first and second casings  12  and  14  and meshes with the pinion  18 , and a driven gear  162  is fixedly mounted on one end of the worm  16 . 
     A drive gear  222  located above the driven gear  162  is rotatably mounted between the first and second casings  12  and  14  and meshes with the driven gear  162 . A drive axle  22  with a square cross-section is integrally formed on one end of the drive gear  222  and extends outward of the first and second casings  12  and  14 . 
     A supporting bracket  24  is received in the headrail  42  and has a first end portion mounted on an underside of the first and second casings  12  and  14 , and a second end portion having two side walls  242  extending upwardly therefrom. Two spaced holes  246  are vertically defined in the second end portion thereof and are located between the two side walls  242 . 
     A first ear  247  and a second ear  248  are formed on the first end portion of the supporting bracket  24  and are each mounted on an outer wall of the first and second casings  12  and  14  respectively. 
     A pin  26  extends sequentially through a second hole  249  defined in the second ear  248 , a second bore  144  defined in the second casing  14 , a first bore  124  defined in the first casing  12  and a first hole (not numbered nor shown) defined in the first ear  247 . A small distal tip of the pin  26  is deformed to prevent its loss. The supporting bracket  24  is thereby attached to the combined first and second casings  12  and  14 . 
     A roller  20  is fixedly mounted to the drive axle  22  and is rotatably received between the two side walls  242  of the supporting bracket  24 . 
     Referring to FIGS. 2 and 4, the roller  20  includes two sides each having a flange  200  extending radially and outwardly therefrom. A recess  201  is defined between the two flanges  200 . Each of the two flanges  200  has a slit  202  defined therein and communicating with the recess  201 . A through hole  204  is longitudinally defined in the roller  20 . 
     A tilt cord  30  extends through the through hole  204  and has a first end  302  extending through one slit  202 , it then winds around the roller  20  and extends downwardly through one hole  246  of the supporting bracket  24 , and has a second end  304  extending through the other slit  202 , it then winds around the roller  20  along a direction opposite to that of the first end  302  and extends downwardly through the other hole  246  of the supporting bracket  24 . 
     Preferably, a knot  32  is formed at a meditate portion of the tilt cord  30  and is stopped by a side wall defining the through hole  204  of the roller  20 . 
     In operation, referring to FIGS. 2 and 3, a user can exert a pulling force on the first end  302  (or the second end  304 ) of the tilt cord  30 , thereby rotating the roller  20  which can force the drive axle  22  to rotate the drive gear  222  which in turn rotates the driven gear  162  together with the worm  16  which is able to rotate the pinion  18  so as to rotate the tilt rod  46 , thereby easily adjusting a rotational angle of the plurality of slats of the Venetian blind  40 . 
     By such an arrangement, the tilt cord  30  can be used to rotate the plurality of slats of the Venetian blind  40  by means of the drive gear  222  co-operating with the driven gear  162  and the worm  16  co-operating with the pinion  18  without having to exert a large pulling force on the tilt cord  30  even when the plurality of slats are made of heavy material such as wood and the like, thereby greatly facilitating operation of the tilt cord  30 . 
     It should be clear to those skilled in the art that further embodiments of the present invention may be made without departing from the scope and spirit of the present invention.