Patent Application
20180100350
The present inventions relate to cordless window shades, and spring drive systems used in cordless window shades.
Many types of window shades are currently available on the market, such as Venetian blinds, roller shades and honeycomb shades. The shade when lowered can cover the area of the window frame, which can reduce the amount of light entering the room through the window and provided increased privacy. Conventionally, the window shade is provided with an operating cord that can be manually actuated to raise or lower a bottom rail of the window shade. The bottom rail can be raised by winding a suspension member around a rotary drum, and lowered by unwinding the suspension member from the rotary drum.
However, there have been concerns that the operating cord of the window shade may pose strangulation threat to children. As a result, cordless window shades have been developed, which use electric motors or spring motors to raise and lower the bottom rail. Spring motors used in window shades generally consist of springs that are operable to apply a torque for keeping the bottom rail at a desired height. However, the conventional assemblies of the spring motors are usually complex, and require multiple moving parts to transmit the spring torque to the rotary drum. This may increase the weight of the spring motor that is provided in the cordless window shade.
Therefore, there is a need for a cordless window shade that has an improved drive system, and can address at least the foregoing issues.
The present application describes a cordless window shade and a spring drive system for use with the cordless window shade. In one embodiment, the spring drive system includes a housing, a rotary drum pivotally connected with the housing and having an inner cavity, a spring shaft connected with the housing coaxial to the rotary drum and extending in the inner cavity of the rotary drum, and a spring disposed in the inner cavity of the rotary drum. The rotary drum has a first and a second circumferential region that surround the inner cavity of the rotary drum, the first circumferential region being connected with an end of a first suspension cord, and the second circumferential region being connected with an end of a second suspension cord. The spring has a first and a second end respectively anchored with the spring shaft and the rotary drum, the spring biasing the rotary drum in rotation for respectively winding the first and second suspension cords around the first and second circumferential regions of the rotary drum.
The head rail 102 may be of any types and shapes. The head rail 102 may be affixed at a top of a window frame, and the shading structure 104 and the bottom part 106 can be suspended from the head rail 102. Moreover, the head rail 102 can have an inner cavity for receiving the spring drive system 110. The inner cavity of the head rail 102 can be sideways closed by two end caps 112 that are respectively attached to two opposite ends of the head rail 102.
The shading structure 104 is suspended from the head rail 102, and can have any suitable constructions. For example, the shading structure 104 can include a cellular structure defined by a flexible or cloth material. Stiff strips 114 may be respectively assembled with an upper and a lower end of the cellular structure so as to facilitate its attachment to the head rail 102 and the bottom part 106.
The bottom part 106 is disposed at a bottom of the window shade 100, and is movable vertically relative to the head rail 102 to expand and collapse the shading structure 104. The bottom part 106 may be formed as an elongated rail. However, any types of weighing structures may be suitable. In some embodiment, the bottom part 106 may also be formed by a lowermost portion of the shading structure 104. The bottom part 106 may have an inner cavity in which the lower end of the shading structure 104 can be attached. The inner cavity of the bottom part 106 can be sideways closed by two end caps 116 that are respectively attached to two opposite ends of the bottom part 106. Moreover, the bottom part 106 can be fixedly connected with a handle 118 that can be grasped by a user for raising and lowering the bottom part 106.
The spring drive system 110 can be affixed with the head rail 102, and can be operatively connected with the bottom part 106. In conjunction with
The housing 120 can define a receiving cavity 132 for assembly of the rotary drum 122 and the spring shaft 124. Moreover, the housing 120 can be respectively assembled with guide shafts 134 and 136 disposed outside the receiving cavity 132. In particular, the two guide shafts 134 can be assembled adjacent to each other at a first side of the receiving cavity 132, and the two guide shafts 136 can be assembled adjacent to each other at a second side of the receiving cavity 132 opposite to the side of the guide shafts 134. When the spring drive system 110 is assembled in the window shade 100, the housing 120 can be fixedly attached to the head rail 102.
The rotary drum 122 is placed in the receiving cavity 132, and is pivotally connected with the housing 120 about a pivot axis P. The rotary drum 122 has an inner cavity 138 that is delimited at least partially by a base 140 and a sidewall 142 projecting from the base 140. The base 140 is substantially perpendicular to the pivot axis P of the rotary drum 122, and can have an opening 144 through which passes the pivot axis P. The sidewall 142 can be generally perpendicular to the base 140, and can have a generally cylindrical shape. Moreover, the rotary drum 122 includes two circumferential regions 146 and 148 that respectively surround the inner cavity 138, and are separated from each other by an annular ridge 150. In one example of implementation, the rotary drum 122, including the base 140, the sidewall 142, the circumferential regions 146 and 148 and the annular ridge 150, can be formed integrally as a single part.
The suspension cord 128 has an end 128A (better shown in
The spring shaft 124 is disposed in the receiving cavity 132, and is fixedly connected with the housing 120 coaxial to the rotary drum 122. In other words, the spring shaft 124 extends generally along the pivot axis P of the rotary drum 122. The spring shaft 124 can extend through the opening 144 of the base 140 into the inner cavity 138 of the rotary drum 122.
The spring 126 can be a ribbon spring, and is disposed in the inner cavity 138 of the rotary drum 122. The spring 126 has an end 126A anchored with the spring shaft 124, and another end 126B anchored with the rotary drum 122 (e.g., by attachment to the sidewall 142 of the rotary drum 122), the spring 126 coiling around the spring shaft 124. The spring 126 thereby assembled can bias the rotary drum 122 in rotation to respectively wind the two suspension cords 128 and 130 around the two circumferential regions 146 and 148 of the rotary drum 122. A washer 152 can be disposed adjacent to the spring 126 for restrictedly positioning the spring 126 in the inner cavity 138 of the rotary drum 122. After the rotary drum 122 and spring 126 are disposed in the receiving cavity 132, a lid 154 can be fastened to the housing 120 to cover the receiving cavity 132 of the housing 120 and the inner cavity 138 of the rotary drum 122.
Once the spring drive system 110 is assembled with the window shade 100, the pivot axis P of the rotary drum 122 can extend generally vertically, and the suspension cords 128 and 130 can respectively extend through openings provided in the shading structure 104 for connection with the bottom part 106.
In conjunction with
Referring to
Once the bottom part 106 is released at a desired height, the biasing force applied by the spring 126 on the rotary drum 122 can counteract a weight exerted on the bottom part 106. As a result, the rotary drum 122 can be kept stationary, and the bottom part 106 can remain stationary at the desired position.
For raising the bottom part 106, an operator can manually push the bottom part 106 upward to collapse at least partially the shading structure 104. While the bottom part 106 rises toward the head rail 102, the spring 126 biases the rotary drum 122 to rotate about the pivot axis P in a direction R2 opposite to the direction R1 to respectively wind the two suspension cords 128 and 130 around the circumferential regions 146 and 148 of the rotary drum 122.
The spring drive system described herein can be implemented in a cost-effective manner, and is suitable for use with various types of window shades including, without limitation, honeycomb shades (as shown herein), Venetian blind, and window shades including a plurality of slats distributed vertically and parallel to one another. Moreover, the spring drive system requires less components parts and is compact in size, which can advantageously reduce the overall weight of the window shade.
Realizations of the structures have been described only in the context of particular embodiments. These embodiments are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Structures and functionality presented as discrete components in the exemplary configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of the claims that follow.
