Patent Application
20130087295
1. Field of the Invention
The present invention relates to a blind slat controller with braking function for rotating and locating blind slats at a predetermined light obstruction angle.
2. Description of the Related Art
A conventional blind slat controller is used to turn open blind slats for light to come into a room or close the blind slats to obstruct the light. The conventional blind slat controller generally includes a cord reel and two pull cords affixed to the cord reel. The pull cords can be pulled up and down to rotate the cord reel for driving and rotating a control shaft. The control shaft then controls the blind slats to rotate to a desired light obstruction angle.
U.S. Pat. Nos. 7,562,600m 6,761,204, 6,601,636, 6,561,254 and 5,636,677 disclose some typical blind slat controllers. The typical blind slat controller generally includes a cord reel and two pull cords wound on the cord reel. The pull cords can be pulled up and down to rotate the cord reel for driving and rotating a shaft rod. The shaft rod in turn drives a control shaft to control the blind slats to rotate to a desired light obstruction angle. The shaft rod is drivingly connected with the control shaft via a thread engagement transmission. There are gaps between the threads and the blind slat controller has no brake structure. Therefore, when the blind slats reach a predetermined light obstruction angle and a user stops pulling the pull cords to stop the cord reel from rotating, the weight of the blind slats will cause a downward pull force. Under the downward pull force, the control shaft is displaced in a reverse direction. In this case, there will be an error in light obstruction angle and the blind slats can be hardly located at the true light obstruction angle. Therefore, the blind equipped with the conventional blind slat controller has poorer light obstruction effect and cannot be accurately operated.
Moreover, the pull cords wound around the cord reel are generally directly suspended from the blind rail and positioned under the window. In this case, a child is likely to play the pull cords and get strangled. This is quite dangerous and leads to poor appearance.
It is therefore a primary object of the present invention to provide a blind slat controller with braking function. The blind slat controller is able to effectively locate blind slats at a predetermined light obstruction angle. At least one coiled spring is fitted on a base seat. A cord reel is used to control the coiled spring to unbind or bind the base seat. When unbound, the cord reel can be rotated to adjust the angle of the blind slats. When bound, the cord reel is braked and prevented from rotating to locate the blind slats at the predetermined light obstruction angle. This overcomes the problems existing in the conventional blind slat controller that the blind slats cannot be truly located and the operation cannot be accurately performed.
It is a further object of the present invention to provide the above blind slat controller, which is able to prevent a child from playing the pull cord and thus protect the child from being strangled by the pull cord.
To achieve the above and other objects, the blind slat controller with braking function of the present invention includes a base seat receivable in a blind rail and having a hub section formed on one side of the base seat, a shaft rod received in the base seat, a worm gear engaged with the shaft rod, a cord reel connected with one end of the shaft rod and a coiled spring fitted on the hub section of the base seat and positioned in the cord reel. The cord reel has a protruding push body. When rotating the cord reel, the push body serves to push a coiled spring to unbind or bind a hub section of the base seat, whereby the cord reel is permitted to rotate or is braked and prevented from rotating. When unbound, a slat control rod can be driven and rotated to control the rotational angle of the blind slats. After the blind slats are rotated to a predetermined light obstruction angle, the cord reel stops rotating. At this time, due to the coiled spring's own elasticity, the coiled spring is restored to again bind the hub section. The bent up stop section of coiled spring serves to stop the cord reel from rotating backward so as to prevent the blind slats from moving downward. Accordingly, the blind slats can be located in their true positions without error in light obstruction angle.
After wound around the cord reel, two ends of the pull cord are conducted out of the blind rail to fixedly connect with a hard pull cord member for ensuring safety. The pull cord member includes a movable sleeve having a hollow interior and an elongated straight rod fitted through the hollow interior of the movable sleeve. Two ends of the pull cord are respectively connected with the movable sleeve and the elongated straight rod. The two ends of the pull cord can be one up and one down pulled by means of operating the movable sleeve or the elongated straight rod to directly control the rotation of the cord reel so as to control and locate the blind slats. The hard structure of the pull cord member prevents a child from playing the pull cord and thus protects the child from being strangled by the pull cord.
The present invention can be best understood through the following description and accompanying drawings, wherein:
Please refer to
Each of the first and second casings 10, 11 is formed with a cavity 100, 110. A semi-tubular protrusion 12, 13 extends from one side of the cavity 100, 110 to define a semicircular trough 120, 130 in communication with the cavity 100, 110. The first and second casings 10, 11 are mated and assembled with each other, whereby the semi-tubular protrusions 12, 13 together form a cylindrical hub section with a central circular hole on one side of the base seat 1. The coiled spring 4 is fitted around the hub section. Two ends of the coiled spring 4 are respectively formed with two bent up stop sections 40, 41. An inner face of each cavity 100, 110 is correspondingly formed with a perforation 101, 111. Two lateral barrel sections 71, 72 of a worm gear are fitted in the perforations 101, 111 respectively, whereby the worm gear 7 is rotatably mounted in the base seat 1. The worm gear 7 has a tooth section 70 engaged with the thread 20 of the shaft rod 2. When the shaft rod 2 is rotated, the worm gear 7 is driven by the shaft rod 2 to rotate. The worm gear 7 is formed with an axial rectangular shaft hole 73. A blind slat control rod is fitted in the shaft hole 73, whereby the blind slat control rod can be driven to rotate the blind slats by different light obstruction angles.
The shaft rod 2 is received in the base seat 1, including a circular rod section 21 with the thread 20 and a rectangular rod section 22. The circular rod section 21 is received in the semicircular troughs 120, 130 of the first and second casings 10, 11, whereby the shaft rod 2 is rotatably restricted within the base seat 1. The rectangular rod section 22 protrudes out of the semicircular troughs 120, 130. A connection body 30 is formed with a rectangular hole 31 corresponding to the rectangular rod section 22. The rectangular rod section 22 is fitted in the rectangular hole 31 to connect with the connection body 30. A front end of the rectangular rod section 22 is formed with an insertion block 23. The insertion block 23 abuts against a closed face 32 of the cord reel 3 to integrally fixedly connect the shaft rod 2 with the cord reel 3. The cord reel 3 is fitted around the cylindrical hub section of the base seat 1 with the connection body 30 received in an open end 301 of the cord reel 3. An upper side of the connection body 30 is formed with a notch 300. A push body 33 protrudes from inner circumference of the open end of the cord reel 3. The notch 300 provides a space for the push body 33 to extend into, whereby the push body 33 can push and twist/untwist the coiled spring 4 so as to unbind or bind the hub section of the base seat 1.
The rotation of the cord reel 3 is controlled by a pull cord 35. Referring to
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The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.
