Plane scroll spring and curtain driving device

Abstract

An embodiment of the present invention provides a plane scroll spring. A torque provided by a working section of a reed of the plane scroll spring is gradually reduced from an outer ring toward an inner ring of the plane scroll spring. The working section includes a first length section and a second length section connected to an inner end of the first length section. In the first length section, the torque decreases by a first decrement value per unit length from the outer ring toward the inner ring. In the second length section, the torque decreases by a second decrement value per unit length from the outer ring toward the inner ring. The first decrement value is less than the second decrement value.

Claims

1. A plane scroll spring, wherein a torque provided by a working section of a reed of the plane scroll spring is gradually reduced from an outer ring toward an inner ring of the plane scroll spring; the working section comprises a first length section and a second length section connected to an inner end of the first length section; wherein in the first length section, the torque decreases by a first decrement value per unit length from the outer ring toward the inner ring; wherein in the second length section, the torque decreases by a second decrement value per unit length from the outer ring toward the inner ring; the first decrement value is less than the second decrement value.

2. The plane scroll spring of claim 1, wherein a flat outer fixing section is formed on a starting end of an outermost reed of the working section.

3. The plane scroll spring of claim 1, wherein an inner fixing portion is formed on an inner end of the reed of an innermost ring of the working section.

4. A curtain driving device, comprising: an intermediate shaft; a mandrel; and a plane scroll spring, wherein an outer end of the plane scroll spring is fixed to the intermediate shaft, and an inner end of the plane scroll spring is fixed to the mandrel; wherein a torque provided by a working section of a reed of the plane scroll spring is gradually reduced from an outer ring toward an inner ring of the plane scroll spring; the working section comprises a first length section and a second length section connected to an inner end of the first length section; wherein in the first length section, the torque decreases by a first decrement value per unit length from the outer ring toward the inner ring; wherein in the second length section, the torque decreases by a second decrement value per unit length from the outer ring toward the inner ring; the first decrement value is less than the second decrement value.

5. The curtain driving device of claim 4, wherein a flat outer fixing section is formed on a starting end of an outermost reed of the working section.

6. The curtain driving device of claim 4, wherein an inner fixing portion is formed on an inner end of the reed of an innermost ring of the working section.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an isometric view of a plane scroll spring of an embodiment of the present invention.

(2) FIG. 2 is a torque distribution diagram showing the torque distribution along the length of the plane scroll spring of an embodiment of the present invention.

(3) FIG. 3 is a graph showing the actual measured torque-turn relationship of an embodiment of the plane scroll spring of the present invention.

(4) FIG. 4 is an isometric view of a curtain driving device of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and illustrations are only used to explain the present invention and are not intended to limit the invention, and in the case of no conflict, that embodiments of the present invention and the features of the embodiments may be combined with each other.

(6) Referring to FIGS. 1 and 2, an embodiment of the present invention provides a plane scroll spring 1. A torque provided by the working section L.sub.AC of a reed 10 of the plane scroll spring 1 is gradually reduced from an outer ring 11 toward an inner ring 12. The working section includes a first length section L.sub.AB and a second length section L.sub.BC connected to an inner end of the first length section L.sub.AB. In the first length section L.sub.AB, the torque T decreases by a first decrement value per unit length from the outer ring 11 toward the inner ring 12. In the second length section L.sub.BC, the torque T decreases by a second decrement value per unit length from the outer ring 11 toward the inner ring 12. The first decrement value is less than the second decrement value.

(7) It should be understood that the working section L.sub.AC of the reed 10 in the present invention refers to a reed section that is subjected to force when the curtain body moves from an initial position of the full contraction of the curtain body to a maximum position of the curtain body. The outer ring 11 and the inner ring 12 mentioned in the present invention are relative concepts, that is, the outer ring 11 is relatively far from the axis of the plane scroll spring 1, and the inner ring 12 is close to the axis of the plane scroll spring 1. Taking the reed in the intermediate layer as an example, the reed in the intermediate layer is the inner ring 12 relative to the reed which is located on the outer side of the intermediate layer, and the reed in the intermediate layer is the outer ring 11 relative to the reed which is located on the inner side of the intermediate layer.

(8) As shown in FIG. 3, it is a torque-turn relationship diagram drawn by the actual measurement of the torque of the plane scroll spring 1 provided by the embodiment of the present invention. The abscissa in the figure represents the number of turns from the outermost ring toward the inner ring. The torque is measured every 0.2 laps in actual measurement. The ordinate represents the measured value of the torque T, and the unit is N.Math.m. Since the plane scroll spring 1 is wound in turn circle by circle, it is obvious that the length of each outer ring 11 will be greater than the length of each inner ring 12, that is, the number of turns per unit length will be sequentially increased from the outer ring 11 toward the inner ring 12. Therefore, as shown in FIG. 3, it is also found that the torque T distribution tendency along the length of the reed 10 is substantially the same as the torque T distribution tendency shown in FIG. 2.

(9) In the embodiment, the working section L.sub.AC of the plane scroll spring 1 is divided into the first length section L.sub.AB and the second length section L.sub.BC. In the first length section L.sub.AB, the torque T provided decreases by the first decrement value per unit length from the outer ring 11 toward the inner ring 12. In the second length section L.sub.BC, the torque T decreases by the second decrement value per unit length from the outer ring 11 toward the inner ring 12. The first decrement value is less than the second decrement value. Therefore, the torque T distribution of the working section L.sub.AC of the plane scroll spring 1 is better matched with the supporting force to be required by the curtain body when the curtain body is lifted to different height positions, so that the smooth and effective supporting force required for the curtain body can always be provided, and the lifting or falling of the curtain body is more stable.

(10) Referring to FIG. 1, in an alternative embodiment, a starting end of the outermost reed 10 of the working section L.sub.AC of the plane scroll spring is provided with a flat outer fixing section 3. In a specific application, referring to FIG. 4, the outer fixing section 3 can be used for being fixed to an intermediate shaft 4 for receiving and winding the plane scroll spring 1. The outer fixing section 3 may be a structure that can fix the starting end of the outermost reed 10 of the plane spiral spring 1 to the corresponding intermediate shaft 4, such as an I-shaped piece, a T-shaped piece, or a rectangular piece defining a circular hole, and the like. The outer fixing section 3 functions as a non-working section and is designed as a straight structure, and does not generate torque itself, so that the outer fixing section 3 can be more conveniently fixed to the corresponding intermediate shaft 4, to improve the assembly efficiency of the plane scroll spring 1.

(11) Referring to FIG. 1, in an alternative embodiment of the present invention, an inner end of the reed 10 of the innermost ring of the working section L.sub.AC of the plane scroll spring 1 is further provided with an inner fixing portion 6. In a specific application, referring to FIG. 4, the inner fixing portion 6 can be used for being fixed to a mandrel 5 for receiving and winding the plane scroll spring 1. The inner fixing portion 6 is constituted by one or more circular reeds having a smaller radius of curvature than the innermost reed 10 of the working section L.sub.AC. In the embodiment, by designing the inner fixing portion 6, the plane scroll spring 1 can be conveniently wound and fixed on the corresponding mandrel 5, and the matching clearance is smaller, so as to prevent the plane scroll spring 1 from shaking during operation and improve the stability of curtains during use.

(12) In another embodiment of the present invention, referring to FIG. 4, the embodiment of the present invention further provides a curtain driving device 7 including an intermediate shaft 4, a mandrel 5, and a plane scroll spring 1. The planar scroll spring 1 is similar to the plane spiral spring 1 as described above. The outer end of the plane scroll spring 1 is fixed to the intermediate shaft 4, and the inner end of the plane scroll spring 1 is fixed to the mandrel 5.

(13) The embodiment of the present invention provides driving power by adopting the aforementioned plane scroll spring 1. The plane scroll spring 1 is connected to the reel of the drawstring through the intermediate shaft 4, to drive the reel. Since the working section L.sub.AC of the plane scroll spring 1 is divided into the first length section L.sub.AB and the second length section L.sub.BC, the torque T provided in the first length section L.sub.AB decreases by the first decrement value per unit length from the outer ring 11 toward the inner ring 12, and the torque T provided in the second length section L.sub.BC decreases by the second decrement value per unit length from the outer ring 11 toward the inner ring 12, and the first decrement value is less than the second decrement value, the torque T distribution of the working section L.sub.AC of the plane scroll spring 1 is better matched with the supporting force required by the curtain body when the curtain body is lifted or lowered to different height positions. Therefore, the smooth and effective supporting force required for the curtain body can always be provided, which makes the lifting or falling of the curtain body smoother.

(14) The specific embodiments of the present invention described above further explain the objects, technical solutions, and beneficial effects of the present invention. It should be understood that the foregoing is only illustrative of specific embodiments of the present invention, and is not intended to limit the scope of the invention. Any modifications, equivalents, improvements, etc. made within the spirit and principles of the present invention are intended to be included in the scope of the present invention.