The present invention relates to a folding/unfolding device for a window shade and, more particularly, to a balanced folding/unfolding device for a shade unit of a window shade without a pull cord.
Window shades can provide a shield from the sun and privacy as well as decoration in rooms and can even show the taste of the users. Modern window shades generally include a pull cord to provide convenient folding/unfolding of a shade unit. However, the exposed length of the pull cord may strangle a child playing nearby, which problem is highlighted in countries that value human rights and demand regulations for safe window shades.
Window shades without a pull cord have been developed and use a driving string to move the shade unit. Specifically, the window shades without a pull cord, though having differences in the main structure, generally includes a set of coiling springs (or known as vortex springs) connected to an end of a driving string. and the other end of the driving string is fixed to the shade unit of the window shade. The weight of the shade unit and the elasticity of the vortex springs are in a balanced state. The balanced state can be manually broken when it is desired to fold or unfold the shade unit. In actual use, a plurality of sets of vortex springs is used and is directly or indirectly connected to a plurality of driving strings, respectively. The driving strings are fixed to the shade unit. The elastic forces could come from different vortex springs and, thus, have difference factors. Furthermore, the forces transmitted to the shade unit could be uneven due to changes in the extending directions of the driving strings. The results are an oblique, shade unit and/or non-smooth folding/unfolding operation of the shade unit.
Thus, a need exists for a novel folding/unfolding device providing even forces transmitted to the driving strings for the shade unit to prevent the oblique state and/or non-smooth folding/unfolding operation of the shade unit.
A balanced folding/unfolding device for a shade unit of a window shade without a pull cord according to the present invention includes a top housing having a first string hole and a second string hole. A reverse winding portion and forward winding portion are mounted in the top housing. A vortex spring unit is mounted in the top housing and includes a first spring mechanism directly or indirectly connected to a first end of a first driving string and a first end of a second driving string. The first driving string and the second driving string extend in the same function. A second end of the first driving string extends around the forward winding portion and then passes downwards through the first cord hole for connection with a shade unit of a window shade without a pull cord. A second end of the second driving string extends around the reverse winding portion and then passes downwards through the second cord hole for connection with the shade unit.
The reverse winding portion can be a guiding column or a guiding wheel. The forward winding portion can be a guiding column or a guiding wheel. The reverse winding portion and the forward winding portion are mounted in a frame. The frame includes a rod extending across the reverse winding portion and the forward winding portion. The first driving string extends around the rod and then extends around the forward winding portion. The second driving string extends around the rod and then extends around the reverse winding portion.
The balanced folding/unfolding device can further include a driving string distributor and a distal string portion. The driving string distributor includes a frame. The reverse winding portion is mounted in aside of the frame adjacent to the vortex spring unit. The forward winding portion is mounted in the other side of the frame distant to the vortex spring unit. The first string hole is located in a bottom of the driving string distributor. The second string hole is located in a bottom of the distal string portion. The first spring mechanism can include a first vortex spring and first, second, and third wheels. One of the first and second wheels coils the first vortex spring while the other of the first and second wheels uncoils the first vortex spring. The first driving string and the second driving string are wound around the third wheel. A gear is mounted to each of the second and third wheels. The gears on the second and third wheels mesh with each other.
The vortex spring unit can further include a second spring mechanism having a second vortex spring and fourth and fifth wheels. One of the fourth and fifth wheels coils the second vortex spring while the other of the fourth and fifth wheels uncoils the second vortex spring. A gear is mounted to each of the first and fifth wheels. The gears on the first and fifth wheels mesh with each other.
The driving string distributor can include two guiding wheels spaced from each other by a gap, and the gap forms the first string hole.
The distal string portion can include two guiding wheels spaced from each other by a gap, and the gap forms the second string hole. Each of the driving string distributor and the distal string portion can include an upright column. The upright column of the driving string distributor guides the first driving string into the first string hole. The upright column of distal string portion guides the second driving string into the second string hole.
The vortex spring unit can be mounted between the driving string distributor and the distal string portion.
The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.
The balanced folding/unfolding device according to the present invention includes a top housing 2 having a first string hole 40 and a second string hole 30. The top housing 2 includes two side boards 21 and 22 for closing two ends thereof.
The balanced folding/unfolding device further includes a reverse winding portion 41 mounted in the top housing 2, a forward winding portion 47 mounted in the top housing 2, and a vortex spring unit 5 mounted in the top housing 2. The vortex spring unit 5 includes a first spring mechanism 5A directly or indirectly connected to a first end of a first driving string 60 and a first end of a second driving string 61. The first driving string 60 and the second driving string 61 extend in the same function. A second end of the first driving string 60 extends around the forward winding portion 47 to change the extending direction and then passes downwards through the first cord hole 40 for connection with the shade unit 1. A second end of the second driving string 60 extends around the reverse winding portion 41 to reverse the extending direction and then passes downwards through the second cord hole 30 for connection with the shade unit 1.
The first spring mechanism 5A is the source of the elastic force for both of the first driving string 60 and the second driving string 61. Furthermore, the second end of the first driving string 60 and the second end of the second driving string 61 are both guided towards the reverse winding portion 41. As mentioned above, the second end of the first driving string 60 extends around the forward winding portion 47 to change the extending direction and then passes downwards through the first cord hole 40 for connection with the shade unit L The second end of the second driving string 60 extends around the reverse winding portion 41 to reverse the extending direction and then passes downwards through the second cord hole 30 for connection with the shade unit 1. Although the first driving string 60 and the second driving string 61 are spaced from each other, the guiding procedures for both of the first driving string 60 and the second driving string 61 are almost the same, such that the pull forces applied by the first driving string 60 and the second driving string 61 are evenly imparted to the shade unit 1 due to the same elastic force source and the substantially identical paths towards the reverse winding portion 41 and the forward winding portion 47. Thus, the driving forces transmitted to the shade unit 1 are even, reducing the risk of the oblique and/or non-smooth folding/unfolding operation of the shade unit 1. The reverse winding portion 41 can be a guiding column or a guiding wheel to reduce friction. Likewise, the forward winding portion 47 can be a guiding column or a guiding wheel to reduce friction. The reverse winding portion 41 and the forward winding portion 47 are mounted in a frame 48. The frame 48 includes a rod 49 extending across the reverse winding portion 41 and the forward winding portion 47. The first driving string 60 extends around the rod 49 and then extends around the forward winding portion 47. The second driving string 61 extends around the rod 49 and then extends around the reverse winding portion 41. The rod 49 provides correction or modification for the first driving string 60 and the second driving string 61 before the winding procedures to obtain substantially synchronous winding states before winding around the forward winding portion 47 and the reverse winding portion 41.
With reference to
In the first and second embodiments, the first spring mechanism 5A includes a first vortex spring 50 and first, second, and third wheels 51, 52, and 53. One of the first and second wheels 51 and 52 coils the first vortex spring 50 while the other of the first and second wheels 51 and 52 uncoils the first vortex spring 50. The first driving string 60 and the second driving string 61 are wound around the third wheel 53. A gear 521, 531 is mounted to each of the second and third wheels 52 and 53. The gears 521 and 531 on the second and third wheels 52 and 53 mesh with each other.
In the first embodiment shown in
With reference to
The gap forms the first string hole 40 to permit smooth passage of the first driving string 60. Likewise, the distal string portion 3 includes two guiding wheels 33 and 34 spaced from each other by a gap, and the gap forms the second string hole 30 to permit smooth passage of the second driving string 61. With reference to
With reference to
Although specific embodiments have been illustrated and described, numerous modifications and variations are still possible without departing from the scope of the invention. The scope of the invention is limited by the accompanying claims.