Patent Publication Number: US-9845639-B2

Title: Blind body brake mechanism for non pull cord window blind

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to window blind technology, and more particularly to a blind body brake mechanism for non pull cord window blind. 
     2. Description of the Related Art 
     Commercial window blinds can be classified into pull-cord window blinds and non pull cord window blinds. A pull-cord window blind uses a pull cord for pulling by a user to move the blind between an extended status and a received status. However, except the drawbacks of laborious operation and poor positioning effect, the neck of a young child playing around a pull-cord window blind is likely to be caught up by the exposed pull cord of the window blind generated choking, resulting in a choking hazard. A non pull cord window blind allows a user to pull down or lift the bottom rail, enabling the blind body to be extended out or received subject to the control of a control mechanism. However, the control mechanisms of conventional non pull cord window blinds commonly have a complicated structure and can simply provide the blind body with a limited transmission effect. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present to provide a blind body brake mechanism for non pull cord window blind, which has the advantages of simple structure and ease of operation and provides the blind body with a good braking effect. 
     To achieve this and other objects of the present invention, a blind body brake mechanism comprises a casing, a rolling-up unit, a transmission unit, and a brake unit. The rolling-up unit comprises two coil spring winding wheels rotatably mounted in the casing and meshed with each other, and a coil spring connected between the two coil spring winding wheels. The transmission unit comprises two transmission gears rotatably mounted in the casing and respectively meshed with one respective coil spring winding wheel, and two transmission cords each having one end thereof respectively connected to one respective transmission gear. The brake unit comprises an operating button mounted in the casing and a return spring. The operating button comprises a braking portion disposed between the two coil spring winding wheels. The return spring is set between the casing and the operating button and adapted for providing an elastic restoring force to the operating button. 
     Thus, when press the operating button, the braking portion of the operating button is released from the two coil spring winding wheels for allowing the two coil spring winding wheels to be rotated synchronously. At this time, the blind body can be extended out or received. When release the pressure from the operating button, the braking portion of the operating button is forced by the return spring into engagement with the two coil spring winding wheels to stop the coil spring winding wheels from rotation, achieving positioning of the blind body. 
     Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational extended-out view of a blind body brake mechanism incorporated non pull cord window blind in accordance with the present invention. 
         FIG. 2  is an oblique top elevational view of the blind body brake mechanism in accordance with the present invention. 
         FIG. 3  is a front view of the blind body brake mechanism in accordance with the present invention. 
         FIG. 4  is a sectional view of the present invention, illustrating the operating button in the release position. 
         FIG. 5  is a top view of the present invention, illustrating the operating button in the release position. 
         FIG. 6  is similar to  FIG. 4 , illustrating the operating button in the press position. 
         FIG. 7  is a top view of the present invention, illustrating a transmission cord extending operation during the operating button in the press position. 
         FIG. 8  is similar to  FIG. 7 , illustrating a transmission cord receiving operation during the operating button in the press position. 
         FIG. 9  is an elevational view illustrating the blind body brake mechanism incorporated non pull cord window blind in the received position in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a blind body brake mechanism  18  is used in a non pull cord window blind  10  in accordance with the present invention. As illustrated, the non pull cord window blind  10  comprises a top rail  12 , an opposing bottom rail  14 , and blind body  16  coupled between the top rail  12  and the bottom rail  14 . Referring to  FIG. 2  and  FIG. 4 , the blind body brake mechanism  18  of the present invention comprises a casing  20 , a rolling-up unit  30 , a transmission unit  40 , and a brake unit  50 . 
     The casing  20  is mounted in the bottom rail  14 , comprising two pairs of guide portions  22  respectively located on each of opposing top and bottom walls thereof. 
     The rolling-up unit  30  comprises two coil spring winding wheels  32 , a coil spring  34  as shown in  FIG. 3 . The two coil spring winding wheels  32  are rotatably mounted in the casing  20  and meshed with each other. The coil spring  34  has two opposite ends thereof respectively connected to the two coil spring winding wheels  32 , enabling the two coil spring winding wheels  32  to be rotated synchronously. 
     The transmission unit  40  comprises two guide rods  42 , two transmission gears  44 , and two transmission cords  46  as shown in  FIG. 2  and  FIG. 5 . The two guide rods  42  are respectively rotatably mounted in two opposite end of the casing  20 . The two transmission gears  44  are rotatably mounted inside the casing  20  and respectively meshed with one respective coil spring winding wheel  32 , so that the transmission gears  44  can be synchronously rotated with the respective coil spring winding wheels  32 . The transmission cords  46  each have respective opposite ends thereof respectively connected to the top rail  12  and the respective transmission gears  44  so that on the one hand the transmission cords  46  can be pulled out by the bottom rail  14 , and on the other hand, the transmission cords  46  can be rolled up by the respective transmission gears  44 . Further, the transmission cords  46  are respectively peripherally abutted against the respective guide rods  42  so that when the transmission cords  46  are being let off or rolled up, they can be moved back and forth along the axial direction of the respective guide rods  42 , enhancing the agility and smoothness of the movement. 
     The brake unit  50  comprises an operating button  51 . The operating button  51  comprises a press portion  52 , two opposite suspension arms  53 , two opposite braking portions  54 , and two opposite pairs of stop blocks  55 . The suspension arms  53  each have one end connected to the press portion  52  and an opposite end provided with two spaced slits  56 . The braking portions  54  are respectively located at a respective one end of one respective suspension arm  53  remote from the press portion  52  and between the associating two slits  56 . The stop blocks  55  are respectively located at the suspension arms  53  at two opposite lateral sides. In installation, the two suspension arms  53  are respectively inserted in between the respective pairs of guide portions  22  of the casing  20 , enabling the operating button  51  to be moved between a press position P 1  (see  FIG. 6  and  FIG. 7 ) and a release position P 2  (see  FIG. 4  and  FIG. 5 ). After installation, the press portion  52  of the operating button  51  is exposed to the outside through an opening (not shown) in the bottom rail  14  for pressing by the user, and, the braking portions  54  of the operating button  51  are disposed between the two coil spring winding wheels  32 . When the operating button  51  is in the press position P 1  shown in  FIG. 6  and  FIG. 7 , the braking portions  54  of the operating button  51  is released from the coil spring winding wheels  32 . When the operating button  51  is in the release position P 2  shown in  FIG. 4  and  FIG. 5 , the braking portions  54  of the operating button  51  is engaged in between the coil spring winding wheels  32 . Further. the brake unit  50  comprises a return spring  57  stopped with two opposite ends thereof between the casing  20  and the press portion  52  of the operating button  51  to provide a restoring force to the operating button  51 , keeping the operating button  51  in the release position P 2 . 
     When wishing to extend out the blind body, apply a force to move the operating button  51  to the press position P 1  shown in  FIG. 6 , releasing the braking portions  54  of the operating button  51  from the coil spring winding wheels  32 . At this time, the return spring  57  is compressed by the press portion  52  of the operating button  51  to store elastic potential energy. Thereafter, pull the bottom rail  14  downward to pull out the transmission cords  46 . When the transmission cords  46  are being pulled out, the transmission gears  44  are rotated (see  FIG. 7 ). During rotation of the transmission gears  44 , the meshed coil spring winding wheels  32  are rotated, causing the coil spring  34  to be wound up from one coil spring winding wheel  32  onto the other coil spring winding wheel  32 , thereby storing an elastic restoring force. Once the user releases the hand from the bottom rail  14  after the blind body  16  reached the desired extended position, the operating button  51  is immediately returned by the return spring  57  to the release position P 2  shown in  FIGS. 4 and 5 , forcing the braking portions  54  of the operating button  51  into engagement between the two coil spring winding wheels  32 . At this time, the coil spring winding wheels  32  are stopped from rotation, enabling the blind body  16  to be held in the extended condition as shown in  FIG. 1 . 
     When wishing to receive the blind body  16 , apply a force to the operating button  51  to move the operating button  51  to the press position P 1  shown in  FIG. 6 , thereby releasing the braking portions  54  of the operating button  51  from the coil spring winding wheels  32 . At this time, the return spring  57  is compressed by the press portion  52  of the operating button  51  to store elastic restoring force. Thereafter, the user can lift the bottom rail  14 . During lifting of the bottom rail  14 , the elastic restoring force of the coil spring  34  forces the two coil spring winding wheels  32  to rotate. During rotation of the coil spring winding wheels  32 , the transmission gears  44  are rotated to roll up the respective transmission cords  46  (see  FIG. 8 ). At this time, the transmission cords  46  are guided by the respective guide rods  42  and wound on the respective transmission gears  44  properly without causing interference or tangling, allowing the transmission cords  46  to be smoothly extended out in a next operation. After the blind body  16  reached the desired position, release the pressure from the operating button  51  and the lifting force from the bottom rail  14 , enabling the operating button  51  to be returned by the return spring  57  to the release position P 2  shown in  FIGS. 4 and 5  where the braking portions  54  of the operating button  51  are engaged in between the two coil spring winding wheels  32 . At this time, the coil spring winding wheels  32  are stopped from rotation, keeping the blind body  16  in the received condition shown in  FIG. 9 . 
     In conclusion, the blind body brake mechanism  18  of the invention uses the operating button  51  for controlling the rotation of the coil spring winding wheels  32  to achieve a good braking effect during the extending or receiving procedure of the blind body  16 , and the guide rods  42  for guiding movement of the transmission cords  46  to let the transmission cords  46  to be smoothly and properly rolled up, and thus, the blind body  16  can be smoothly and steadily extended out or received.