Abstract:
The present invention pertains to an electric roman shade mainly utilizing the controller to rotate the power motor and the roller bar, thus motivating the covering sheet upward and downward. Additionally, by means of the revolving shaft having threads disposed thereon, the cord thus sequentially wraps the shaft without overlapping thereby steadily adjusting movements of the sheet. Further, the covering sheet would automatically stop working while the sliding sections touching the switching tabs, and users can also rise and descend the sheet at desired positions, thus increasing the convenience of using.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a window covering design, in particular to an electric roman shade. 
         [0003]    2. Description of the Related Art 
         [0004]    Referring to  FIG. 1 , a conventional roman shade  1  comprises a head rail  11 , a pleated sheet  12  with one end affixed to the rail  11  and a transmission device  13  for driving the sheet  12 ; wherein, the rail  11  has an inner space  111  therein and an interlocking surface  14  secured to the front side thereof (as shown in  FIG. 2 ), further a loop and hook strip  121  is attached to the upper edge of the sheet  12  for being adhesive to the interlocking surface  14 . Additionally, the transmission device  13  consists of a roller bar  131  located in the space  111 , a rolling pulley  133  attached to the bar  131 , a cord control  132  arranged round the pulley  133 , and a plurality of cord spools  16  equidistantly spaced on the bar  131 , each of which further comprises a base  161  fastened to the bar  11 , a rolling shaft  162  on the base  161 , and a cord  163  wrapped the shaft  162  having one end thereof attached to the sheet  12 . 
         [0005]    While in manipulation, users need to pull the cord control  132  to rotate the pulley  133  and the bar  131 , and simultaneously the shaft  162  becomes revolving as well to descend or lift the sheet  12  by freeing or retracting the cord  163 . Nevertheless, the conventional shade  1  requires a manual operation and probably results in the interruption of the spools  16  if imparting an uneven pulling to cord control  43 , thus it is inconvenient. By means of the shaft  162  of the spool  16  having a smooth surface, the cord  163  readily become overlapped while furling the sheet  12 , which in turn affects the output thereof in time of freeing cord  163  and the sheet  12  may not have its pendent edge to present in a uniform length, thus still needs improvements. 
       SUMMARY OF THE INVENTION 
       [0006]    Therefore, the object of the present invention is to provide an electric roman shade which sequentially and steadily transports cord without imparting a manual force so as to increase convenience of using and retain a tidy appearance of the sheet. 
         [0007]    The electric roman shade in accordance with the present invention mainly provides with a head rail, a covering sheet, a transmission apparatus and a controlling mechanism. Particularly, the transmission apparatus has a roller bar in the rail, a power motor disposed thereon for driving the bar and cord spools periodically spaced on the bar; each cord spool has a revolving shaft with threads thereon and a cord convolved thereon, thereby steadily and smoothly outputting the cord to descend or lift the covering sheet. Furthermore, the controlling mechanism, which comprises a receiver, a controller attached thereto, and a limiter electrically engaged to the controller, assists to automatically motivate the motor and the bar and then rotate the cord spool in order to prevent the conventional manual method and efficiently increase the using convenience. 
         [0008]    The advantages of the present invention over the known prior arts will become more apparent to those of ordinary skilled in the art by reading the following descriptions with the relating drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a schematic view showing a conventional invention; 
           [0010]      FIG. 2  is a side perspective view showing the conventional invention; 
           [0011]      FIG. 3  is an exploded view showing a first preferred embodiment of the present invention; 
           [0012]      FIG. 4  is a schematic view showing the first embodiment of the present invention; 
           [0013]      FIG. 5  is a partial enlarged view showing the elements of the first embodiment; 
           [0014]      FIG. 6  is a schematic view showing the first embodiment of the present invention in time of operating; 
           [0015]      FIG. 7  is a schematic view showing a second preferred embodiment of the present invention; 
           [0016]      FIG. 8  is an exploded view showing a third preferred embodiment of the present invention; and 
           [0017]      FIG. 9  is a schematic view showing the concatenation of elements of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Before describing in greater detail, it should note that the like elements are denoted by the similar reference numerals throughout the disclosure. 
         [0019]    Referring to  FIGS. 3 and 4 , an electric roman shade  2  of the first preferred embodiment is comprised of a head rail  21 , a covering sheet  22  secured to the rail  21 , a transmission apparatus  23  disposed inside the rail  21  and a controlling mechanism  24  for driving the transmission apparatus  23 ; wherein, the head rail  21  has an inner space  211  therein, and the covering sheet  22  with one end thereof is fastened to the rail  21  and a bottom rail  221  is formed at the other end thereof. 
         [0020]    Continuing with the aforementioned, the transmission apparatus  23  includes a roller bar  231  mounted in the inner space  211 , a power motor  232  secured to the bar  231  and more than one cord spool  233  equidistantly spaced on the bar  231 ; wherein, a planetary gear assembly  238  (more definitely shown in  FIG. 4 ) is located between the power motor  232  and the roller bar  231  for reinforcing a dynamic force of the power motor  232  to rotate the roller bar  231 ; each cord spool  233  further consists of a cord body  234  disposed said head rail  21 , a revolving shaft  235  mounted on the cord body  234 , and a cord  236  spiraled round the revolving shaft  235  and attached its end to the bottom rail  221 ; the revolving shaft  235  further provides with a plurality of threads  237  disposed thereon and a concave track  2371  arranged between each two threads  237  for permitting the cord  236  convoluted along the track  2371  while rotating the shaft  235 . 
         [0021]    Referring to  FIG. 4 and 5 , the controlling mechanism  24  further comprises a receiver  241  to receipt signals, a controller  242  attached to the receiver  241  and a limiter  243  electrically engaged to the controller  242 ; wherein, the singles emitted through a remote controller  3  is received by the receiver  241  and further transmitted to the controller  242 ; the limiter  243  provides with a shield base  244  disposed within the inner space  211 , a threaded shank  239  mounted to the base  244  and contacted to the roller bar  231 , dual switching tabs  248  separately disposed on two sides of the base  244  and two sliding sections  247  respectively pivoted to the threaded shank  239 . Additionally, the switching tabs  248  can be designed in an electronic induction or an automatic pressing forms, and the pressing tabs are adopted in the embodiments; the switching tabs  248  connect to the controller  242  by circuits and simultaneously attach to the power motor  232  thereby, so that the controller  242  could communicate with the power motor  232  in order to drive it rotating(shown in  FIG. 5 ); furthermore, the covering sheet  22  would automatically stop working until the sliding sections  247  hits one of the tabs  248 . 
         [0022]    Further referring to  FIG. 5 and 6 , in operation, users initially press the remote controller  3  to send signals to the receiver  241  and thereafter the receiver  241  transmits them to the controller  242 , the power motor  232  thus is driven and enhances its dynamic force through the planetary gear assembly  238  to synchronously revolve the roller bar  231  and the cord spool  233 , so as to free the cord  236  and smoothly descend the covering sheet  22  as well. By means of the threads  237  disposed on the revolving shaft  235 , the cord  236  begins to regularly deviate from the cord spool  233  along the concave track  2371 , thereby descending the covering sheet  22 . Simultaneously, the limiter  243  is also driven by the power motor  232 , namely the threaded shank  239  is also rotated by the roller bar  231  and renders the sliding sections  247  traveling thereon toward a direction (arrowed in the solid line in  FIG. 6 ), and thereafter the power motor  232  automatically stops working and the covering sheet  22  stops as well at the predetermined position until one of the sliding sections  247  touches its adjacent switching tab  248 , whereby the bottom rail  221  keeps a uniform length of its pendent edge and achieves a window blind advantage and. Deservedly, the remote controller  3  can directly suspend the covering sheet  22  at desired positions. 
         [0023]    Reciprocally, when the remote controller  3  drives the controller  242  and the power motor  232  to lift the covering sheet  22 , the sliding sections  247  remove toward another direction ( as arrowed in dotted line) and simultaneously the cord  236  in turn convolutes the revolving shaft  235  along the concave track  2371  to avoid the overlapping thereof, thereby steadily furling the cord  236  and raising the bottom rail  221  upward to its desired position or automatically stopping it until the sliding sections  247  touch the reverse switching tab  248 . 
         [0024]    Referring to  FIG. 7 , a second preferred embodiment of the present invention comprises the similar elements, operations and functions to the first preferred embodiment. Differentially, a certain amount of noise abatement cotton  212  fills the inner space  211 , and the cotton  212  wraps the transmission apparatus  23  so as to reduce the noise generated therefrom in operation. 
         [0025]    Referring to  FIG. 8 , a third preferred embodiment of the present invention is still comprised of the similar elements to the first embodiment. Particularly, an attachable mechanism  33  located between the head rail  21  and the covering sheet  22  comprises a folding assembly  331  fastened to the head rail  21  and a housing assembly  332  attached to the covering sheet  22 ; wherein, the folding assembly  331  has a plate  337 , a rod  338  attached to the plate  337  and a beveled bracket  339  protruding from the plate  337 ; the housing assembly  332  has a housing body  333 , a socket  334  affixed to the housing body  333  and a beveled plate  335  below the socket  334  protruding from the housing body  333 . Further, the beveled bracket  339  and the plate  337  intersects to form a free space  330 , where the beveled plate  335  can enter, and the socket  334 , for instance formed of a C-shape, further defines an interior  336  therein for receiving the rod  338 . 
         [0026]    Referring to  FIG. 9 , while installing, the folding assembly  331  is initially fastened to the head rail  21  by screws. Subsequently, the beveled plate  335  is inserted into the free space  330  and further the rod  338  is snapped into the interior  336  of the socket  334 , which results of the beveled bracket  339  being located below the beveled plate  335  for a sustaining advantage so that the housing assembly  332  can firmly attach to the folding assembly  331 . 
         [0027]    To sum up, the present invention takes advantages of the controlling mechanism which directly drives the power motor and automatically controls the movements of the covering sheet at desired positions so as to manipulate without imparting a manual force, and further the threads of the revolving shaft prevents the cord from being irregularly convoluted on the shaft and facilitates to steadily free or furl the cord, thus efficiently increasing the convenience and obtaining a good appearance of the sheet. 
         [0028]    While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.