Patent Application
20080099157
1. Field of Invention
The present invention relates to a device for winding a suspension cord of a blind, and more particularly to a device for winding a suspension cord of a blind, which arranges the suspension cord on a cord spool in sequence through a guide means and adjusts the output torque of the cord spool by using the friction force applied to the cord spool by an adjusting means.
2. Related Art
A cordless blind utilizes a spring housing as a power source, and the torque applied to a cord spool by the spring housing is balanced out with the torque applied to the cord spool by the gravity of the blind. Therefore, the blind can be kept at any position.
The relevant technology has been disclosed in some U.S. patents. U.S. Patent Publication No. 5,706,876 has disclosed that a suspension cord is wound when a roller shade bar is rotated, and a power spring is disposed in the roller shade bar to generate the power of rotation for winding the suspension cord.
U.S. Patent Publication No. 5,813,447 has also disclosed that the roller shade bar is rotated and moved in an axial direction to arrange the suspension cords along the surface of the roller shade bar, thereby preventing the suspension cords from intertangling together. However, the structure for winding the suspension cords is complicated and the space for the roller shade bar to move in an axial direction is limited. Therefore, such structure is unsuitable for a blind with a large size or long suspension cords.
U.S. Patent Publication No. 5,133,399 and U.S. Patent Publication No. 5,328,113 have disclosed that the cord spool has a taper and the spring housing is also used as a power source. The suspension cords can be arranged on the surface of the cord spool automatically when being wound. Therefore, the structure for winding the suspension cords is simple. In U.S. Patent Publication No. 5,133,399, spiral grooves are formed in the surface of the cord spool for accommodating suspension cords, however, a long suspension cord needs an accordant spiral groove of the cord spool, thus, the cord spool should be of a larger size for completely accommodating a long suspension cords. Therefore, the cord spool should have different sizes for the length of the suspension cord varies with different occasions for fitting a blind. Spiral grooves formed in the surface of the cord spool must increase the manufacturing cost. In U.S. Patent Publication No. 5,328,113, the cord spool shapes like a taper, such that the suspension cord may be arranged on the cord spool with a taper automatically when winding a suspension cord. However, there is no guide mechanism between the suspension cord and the cord spool, and the portion with a taper is far away from the position where the suspension cord corresponds to the cord spool. As such, the suspension cord will be easily seized during the later stage of winding the suspension cord due to the absence of the guide of the taper, resulting in the non-smoothness in winding the suspension cord. Additionally, the torque of the spring housing will be attenuated as the time passes and the frequency of use increases. The attenuated torque of the spring housing cannot be balanced out with the torque applied to the cord spool by the gravity of the blind. Therefore, the blind cannot be fixed due to the gravity thereof, and such problem cannot be solved until the spring housing is replaced. Additionally, the size of the blind should be slightly adjusted depending on different installation occasions. Thus, the gravity of the blind is various, while the torque of the spring housing is constant, resulting in that the spring housing cannot be completely suitable for the blinds with different sizes.
However, the device for winding a suspension cord without using the spring housing often suffers from the problem of the non-smoothness in winding the suspension cord. Therefore, the smoothness in winding the suspension cord becomes a topic to be studied.
In view of the aforementioned problems needed to be solved, the device for winding a suspension cord of a blind provided by the present invention may arrange the suspension cord on a cord spool in sequence and can compensate the torque of a power resilient element for the blinds of different sizes.
Accordingly, the present invention provides a device for winding a suspension cord of a blind which is used to wind a suspension cord passing through at least one covering material of a blind. The device for winding a suspension cord of a blind comprises a power resilient element, a pedestal, a cord spool, a guide means and an adjusting means. The cord spool is pivoted to the pedestal and driven by the power resilient element to rotate, such that the suspension cord is guided by the guide means to be wound about the cord spool smoothly and sequentially. Additionally, the adjusting means is mounted on the pedestal to apply a friction force to the cord spool to damp the rotation of the cord spool, thereby balancing out the torque applied to the cord spool by the power resilient element and the torque applied to the cord spool by the covering material of the blind.
Furthermore, the present invention provides a module for winding a suspension cord of a blind, which is used to wind a suspension cord passing through at least one covering material of a blind. The module for winding a suspension cord of a blind comprises a pedestal, a cord spool, and a guide means. The cord spool is pivoted to the pedestal and is rotated to wind the suspension cord. The guide means has a guide portion, which is used to guide the suspension cord to be wound about the cord spool and arrange the suspension cord along the cord spool in sequence.
In the present invention, the guide means guides the suspension cord such that the suspension cord is wound about the cord spool by a specific angle, and with the taper of the cord spool, the suspension cord is arranged on the cord spool in sequence. When the cord spool is connected to the power resilient element as a power source for rotation, the present invention further provides the adjusting means. The adjusting means applies friction force to the cord spool to adjust the torque of the cord spool. When the present invention is applied to the blinds with different sizes, or the power resilient element has an insufficient torque due to the attenuation of the elastic force, the torque applied to the suspension cord by the cord spool can be constant by reducing the friction force. Therefore, the device for winding a suspension cord of a blind provided by the present invention can wind the suspension cord about the cord spool smoothly and can be used for the blinds of different sizes by adjusting the torque applied to the suspension cord by the cord spool. Furthermore, when the elastic force of the power resilient element attenuates, the torque of the cord spool can also be adjusted to achieve the efficacies of being commonly used, conventional assembling, and subsequent adjustment.
The features and practice of the preferred embodiments of the present invention will be illustrated below in detail with reference to the drawings.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein:
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One end of the cord spool 300 is connected to a power resilient element 700 through a rotating shaft 910, and a pedestal 310 and a guide means 330 are mounted to a top rail 900. The pedestal 310 is adjacent to the guide means 330 and used for bearing the cord spool 300 to be rotated. The suspension cord 110 passes through the pedestal 310 from bottom to top, then passes through the guide means 330 laterally, and is finally wound about the cord spool 300.
An adjusting means 500 is further disposed on the pedestal 310 and is used to adjust the resistance force occurring when the cord spool 300 is rotated, so as to solve the problems that the elastic force of the power resilient element 700 is attenuated after long-term usage and the blinds of different sizes require different elastic forces.
Furthermore, a cover 800 has one end buckled in the pedestal 310, and the other end pivoted to one end of the cord spool 300 far away from the pedestal 310, such that the two ends of the cord spool 300 are respectively pivoted to the pedestal 300 and the cover 800. Therefore, the cord spool 300 may be rotated smoothly.
The power resilient element 700 is a spring housing, which uses a power spring as a power source. The power spring may be used to generate torque, and it is a constant force spring.
The rotating shaft 910 passes through the axle center of the cord spool 300, and is connected to one or more power resilient elements 700 with one end or both two ends thereof, and passes through multiple devices for winding a suspension cord disposed on in the top rail 900.
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Besides, an annular accommodation space formed between the cover 800 and the cord spool 300 is used to accommodate the suspension cord 110 wound around the cord spool 300, and the space between the cover 800 and the cord spool 300 is slightly greater than the diameter of the suspension cord 110 and smaller than the double diameters of the suspension cord 110, such that the suspension cord 110 is wound about the cord spool 300 sequentially and smoothly and prevented from being wound about the cord spool 300 overlappedly.
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A bolt hole 515 is formed beside the through hole 513, and the knob has a screw axis 571. A screw thread is formed on a part of the surface of the screw axis 571 to be screw-connected to the bolt hole 515. Furthermore, the free end of the screw axis 571 has a retaining ring 573 extending along the outer circumference of the screw axis 571. A second hole 535 is opened beside the sliding bar 533 of the tablet 530, such that the retaining ring 573 of the screw axis 571 passes through the second hole 535 and presses against the circumference of the second hole 535, therefore, one end of the knob may slide in the second hole 535.
A resilient element 550 is fitted in the knob and placed between the tablet 530 and the fixed plate 510, so as to be compressed by the tablet 530 and the fixed plate 510 to generate an elastic force, which drives the tablet 530 to face the cord spool 300. As such, the tablet 530 can constantly press against the retaining ring 573 and press the surface of the cord spool 300, so as to form damping effect through the friction force correspondingly generated by the positive pressure on the surface of the cord spool 300, and reduce the torque when the cord spool 300 is driven to rotate by each of the resilient elements 700 and the rotating shaft 910.
Of course, the arc plate 531 at the lower end of the tablet 530 can be directly pressed on the surface of the cord spool 300. However, in this embodiment, a blade spring 537 respectively extends from the left side and right side of the arc plate 531. The blade springs 537 press against the cord spool 300, and adjust the height of the tablet 530 by rotating the knob, so as to adjust the application force applied by the blade springs 537 pressing against the cord spool 300.
Therefore, the relational expression of the torque Ts applied to the cord spool 300 by the power resilient element 700, the torque Tf applied to the cord spool 300 by the friction force generated by the tablet 530 pressing against the cord spool 300, and the torque Tc generated when the suspension cord 110 holds the cord spool 300 is Ts+Tf=Tc.
The rotation of the cord spool 300 is hindered by the toque Tf, thus it can be balanced out with the torque Ts. Therefore, the torque Tf can be changed by the application force generated when the tablet 530 presses against the cord spool 300, thereby adjusting the torque of the cord spool 300. When the resilient element 700 has attenuated elastic force after long-term usage, the torque Ts is reduced. The pressure applied to the cord spool 300 by the tablet 530 is reduced by adjusting knob, so as to reduce the resistance force of the torque Tf on the cord spool 300. As such, the torque Ts and the torque Tc can be balanced out with each other. In another aspect, when assembling, due to the different sizes of windows, blinds should be suitably cut accordingly, thus the torque Tc changes as well. However, the torque Ts is generally constant. Therefore, when the torque Tc changes, the pressure applied to the cord spool 300 by the tablet 530 may be used to change the toque Tf. Similarly, the torque Ts and the torque Tc can be balanced out with each other.
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The pedestal, the cord spool, and the guide means may be combined to form a module for winding a suspension cord of a blind. Such module is driven by the suspension cord or the power resilient element to rotate the cord spool, and can be commonly used in a blind winding structure with or without the suspension cord.
Therefore, the device for winding a suspension cord of a blind provided by the present invention can adjust the torque of the power resilient element to be suitable for blinds with different sizes, and also can be used to reduce the limitation on the torque of the power resilient element when the torque of the power resilient element is decreased, such that the torque applied to the blind by the power resilient element is increased, so as to compensate the attenuated elastic force. Furthermore, the device for winding a suspension cord of a blind according to the present invention is equally applicable to other types of blinds, including but not limited to, curtain, cellular shade and the like.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
