Blind body collecting-expanding control device for window blinds

[0001] The present invention relates to a blind body collecting-expanding control device for window blinds wherein a cord-winding control device equipped with torsion springs is utilized to interact with the pushing or pulling force exerted by hands onto a bottom rail to loosen or tighten lift cords coiled onto a winding shaft, forming a counter-balance there-between so that a user can freely adjust the blind body into a desirable position without hurting the hands in operation, achieving the best adjustment effect as well as speedy assembly thereby.

[0002] A conventional window blinds structure includes a blind body, a transmission assembly, and pull cords drawn by force of hands to adjust the position of the blind body thereby. In operation, due to the small frictional surface of the cord bodies thereof, the pull cords tend to rub against the hands or abrade the hands directly contacting with them. Furthermore, to adjust the blind body into an expanded or collected position, the blind body becomes difficult to be accurately positioned in a desirable position in case of an excessive down-pulling force exerted onto the pull cords or a sudden release of the pull cords at great speed. As a result, the adjustment process must be repeated over again, which is quite inconvenient in operation.

[0003] It is, therefore, the primary purpose of the present invention to provide a blind body collecting-expanding control device for window blinds wherein pushing or pulling force of hands cooperatively works with the elasticity generated by torsion springs of a cord-winding control device so that a user can freely adjust a blind body into a desirable position without hurting or abrading the hands in operation thereof, achieving the best state of application thereby.

[0004] It is, therefore, the second purpose of the present invention to provide a blind body collecting-expanding control device for window blinds wherein, via the pushing or pulling force exerted by hands to interact with the elasticity generated by the torsion springs of the cord-winding control device, the blind body can be accurately adjusted by hands to reach a desirable collected or expanded position without the inconvenient process of repeated adjustment as found in the application of the conventional pull cords above, achieving more accurate and simpler operation as well as assembly thereof.

[0005] FIG. 1 is an exploded perspective view of the present invention.

[0006] FIG. 2 is an exploded perspective view of a cord-winding control device of the present invention.

[0007] FIG. 3 is an assembled perspective view of the present invention.

[0008] FIG. 4 is a partially enlarged and assembled view of the present invention.

[0009] FIG. 5 is a rear side view of torsion springs assembled onto a rotary seat of the cord-winding control device of the present invention.

[0010] FIG. 6 is a diagram showing a blind body of the present invention expanded downwards.

[0011] FIG. 7 is a diagram showing the blind body of the present invention collected upwards.

[0012] FIG. 8 is an assembled view of another embodiment of the present invention.

[0013] Please refer to FIG. 1 showing an exploded perspective view of the present invention. The present invention relates to a blind body collecting-expanding control device for window blinds, comprising a head rail 10, a bottom rail 20, a cord-winding control device 30, a transmission assembly 40, and a blind body 50. The head rail 10 has an accommodating channel 11 defining at one end thereon, and the cord-winding control device 30 (referring to FIG. 2) is equipped with a set of upper and lower housings 31, 31′, a rotary seat 32, and two torsion springs 33. The upper and lower housings 31, 31′ are respectively provided with male/female reciprocal conjoining sections and symmetrical portions that are capable of reciprocally joining to each other to form an enclosed positioning box thereby. The lower housing 31′ is identically shaped like the upper housing 31, and set in reverse directions therewith so that the upper and lower housings 31, 31′ can be placed in reverse to precisely close up onto each other. The upper housing 31, shaped in a U-shaped elongated groove, is equipped with a set of stop seats 311, 312 that, each defined by an arcuate inner wall, symmetrically extend at both lateral side edges thereon wherein one stop seat 311 has an insert hook 313 extending at the top surface thereon, and the other stop seat 312 has a recess 314 defining the outer wall to correspond to the position of the insert hook 313 thereof. The two stop seats 312 surround a shallow stepwise annular groove 315 defining the middle section of the upper housing 31. The annular groove 315 has a central shaft 316 extending upwards in the middle thereon. A protruding post 3161 and a bore 3162 are disposed on the top surface of the central shaft 316 thereon. Positioning rods 317 are symmetrically provided protruding at the four corners along the outer circumferential edge of the annular groove 315 thereon wherein the positioning rods 317 are respectively corresponded to the two stop seats 311, 312 to define two positioning arcuate grooves 3171 thereby. The two positioning arcuate grooves 3171 are respectively provided with an axle 318, 319 protruding upwards in the middle thereon wherein one axle 318 has a grooved hole 3181 defining the top surface thereon, while the other axle 319 has a protrusive rib 3191 extending at the counterpart top surface thereon. The rotary seat 32 is made up of a cylindrical actuation body 321 extending at one side, and the cylindrical actuation body 321 is equipped with a counter-winding surface 323 with fixing holes 322 defining thereon. A coiling surface 324 equipped with a roller seat is provided extending at the other side of the rotary seat 32. A stop portion 326 with a central opening 327 extending in the middle is attached to one side of the coiling surface 324, and an abutment face 325 is formed at the conjoining section of the counter-winding surface 323 and the coiling surface 324 thereof. Thus, the counter-winding surface 323 of the rotary seat 32 is allowed to mount to the central shaft 316 with the abutment face 325 precisely located in place astride onto the positioning rods 317 thereon. The transmission assembly 40 is composed of support seats 41, 42, a winding shaft 43, lift cords 44, an operational cord 45, and a sliding element 46. The support seats 41, 42 are respectively equipped with a guide passage 411, 421 at one side for the extension of the winding shaft 43 there-through. The lift cords 44 and the operational cord 45 can be made of strap bodies or cable ropes, etc.

[0014] Please refer to FIG. 3 accompanied by FIG. 4. In assembly, the upper and lower housings 31, 31′ of the cord-winding control device 30 are correspondingly put in reverse to each other, and the two torsion springs 33 are respectively attached to the actuation body 321 of the rotary seat 32 via inverted hooked portions disposed at the coupling end thereon to be firmly hooked to the fixing holes 322 defining both sides of the counter-winding surface 323 so that the two torsion springs 33 are allowed to juxtapose in parallel and operate in a reversible S-shaped rotation as shown in FIG. 5. Then, the two torsion springs 33 are respectively mounted to the axles 318, 319 extending at the two positioning arcuate grooves 3171 of the lower housing 31′, and the actuation body 321 of the rotary seat 32 is coupled with the central shaft 316 of the annular groove 315, permitting the abutment face 325 of the rotary seat 32 to locate in place astride onto the positioning rods 317 and restrict one side edge of the two parallel torsion springs 33. Then, the upper housing 31 is covered on top of the lower housing 31′, permitting the male/female conjoining sections and symmetrical portions of the upper and lower housings 31, 31′ thereof to reciprocally couple with each other and complete the assembly of the cord-winding control device 30. The cord-winding control device 30 is fixedly mounted into the accommodating channel 11, and the support seats 41, 42 are spaced out in appropriate distance and firmly located into the head rail 10. Via the guide passages 411, 421, the winding shaft 43 is mounted to hold between the support seats 41, 42 and capable of rolling thereon. The operational cord 45 is applied to wind through the sliding element 46 of the support seat 42 and the rotary seat 32 to provide sliding guidance there-between. Then, depending on their respectively positions led through the blind body 50, the two lift cords 44 are guided to coil around both end sides of the winding shaft 43, each located at one side of the two support seats 41, 42. The lift cords mounted to the head rail 10 and the blind body 50 are respectively fixed to the bottom rail 20 thereon. And the operational cord 45, attached to one end of the winding shaft 43 at one side, is guided to wind through the sliding element 46 before fixedly attached to the coiling surface 324 at the other end thereof.

[0015] In operation, when the blind body 50 (referring to FIG. 6) is to be expanded downwards, the bottom rail 20 is pulled downwards by the force of hands, and the lift cords 44 will be drawn downwards to actuate the rotation of the winding shaft 43 therewith. Then, the winding shaft 43 will spin to the right to release the lift cords 44, and the operational cord 45 will run through the sliding element 46 to coil up at one end of the winding shaft 43 thereon. Meanwhile, the operational cord 45 will actuate the coiling surface 324, permitting the actuation body 321 to revolve in counterclockwise rotation. The two torsion springs 33 arranged in parallel to augment the elasticity thereby will be affected by the pulling force of the actuation body 321 to revolve in a reverse S-shaped movement with a constant torque naturally occurred and to counter wind tight onto the counter-winding surface 323 thereon. Then, the constant torque occurred works in a linear operation and the torque will not be altered due to the increase of the coils wound, reinforcing the strengthen of the blind body 50 affected by the pulling force to achieve efficient suspension thereby.

[0016] When the blind body 50 (referring to FIG. 7) is to be collected upwards, the bottom rail 20 is pushed upwards by the force of hands, and the torsion springs 33 counter-wound onto the counter-winding surface 323 thereon will be released to naturally recoil backwards, permitting the actuation body 321 to spin in clockwise rotation with a constant torque occurred at the same time. Then, the operational cord 45 coiled onto the winding shaft 43 will run through the sliding element 46 to rewind onto the coiling surface 324 thereon, and synchronically actuate the winding shaft 43 to spin to the left so as to wind upwards the lift cords 44 and collect the blind body 50 thereby. Therefore, the pushing and pulling force exerted by hands cooperatively interacts with the cord-winding control device 30 to generate constant torques and actuate movements in an easy manner without the hands getting abraded by the pull cords of the conventional window blind structure so that a user can freely adjust the blind body 50 into a desirable position, achieving the best application state thereby.

[0017] Please refer to FIG. 8 showing an assembled view of another embodiment of the present invention. To be installed into a smaller-size blind body 50, the cord-winding control device 30 can have one of the two parallel torsion springs 33 directly dismantled and removed there-from before mounted into the accommodating channel 11 of the head rail 10, permitting the blind body 50 to be collected or expanded in the same natural manner.