Constant-force spring assembly

Abstract

The utility model provides a constant-force spring assembly. The constant-force spring assembly comprises a first inner rod arranged at the left end and a coaxial second inner rod arranged at the right end. Bearings are arranged on the first inner rod and the second inner rod respectively, a first shell is coaxially arranged on the bearing of the first inner rod, and a second shell is coaxially arranged on the bearing of the second inner rod; a constant-force spring module or at least two constant-force spring modules which are arranged in parallel are arranged between the first inner rod and the second inner rod; each constant-force spring module comprises a torsion core, a constant-force spring and a spring cavity which are coaxial; one end of the constant-force spring is fixed on the torsion core, and the other end of the constant-force spring is fixed on the spring cavity; the first inner rod and the second inner rod are respectively coaxial and detachably connected with the torsion core adjacent to the first inner rod and the second inner rod, and the first shell and the second shell are respectively coaxial and detachably connected with the spring cavity adjacent to the first shell and the second shell. According to the utility model, the problems of tedious preparation work and high cost in the early-stage debugging of the curtain spring are solved.

Description

Technical Field

[0001] The utility model belongs to the field of constant force springs, and particularly relates to a constant force spring assembly. Background Art

[0002] In a fixed-width curtain system, the spring torque required for the tube and the lower beam is constant. The only variable for the spring torque required for the curtain is the fabric. Moreover, as the pulling-down height increases, the weight of the fabric gradually increases. At the same pulling-down height, the weights of different fabrics are also different. Therefore, constant force springs of different specifications are required. The ordinary springs produced and sold in the current market have a force difference during the up and down operation, and the debugging difficulty is large. The specifications of the constant force springs are mostly in units of the whole. When debugging the curtain, a large number of constant force springs of different specifications need to be prepared for replacement and testing. The specification range is small, and the replacement is troublesome. Moreover, in order to fit more curtain specifications, many kinds of spring assemblies need to be reserved, or the weight of the lower beam is increased to reduce the specifications of the spring assembly, which will not only increase the inventory but also increase the cost. Patent CN202211275214 discloses a curtain, which includes several spring modules. However, in the above modules, the inner core and the outer rotating shell are both integrally arranged, and the length cannot be increased or decreased according to the number of spring modules, and it cannot adapt to various situations. Moreover, the frictional resistance during the rotation of the spring module in the comparative document is large, which easily causes elastic force consumption. Summary of the Invention

[0003] The utility model provides a constant force spring assembly.

[0004] The purpose of the utility model is achieved in the following way: A constant force spring assembly includes a first inner rod arranged at the left end and a second inner rod arranged coaxially at the right end; bearings are respectively arranged on the first inner rod and the second inner rod. A first shell is coaxially arranged on the bearing of the first inner rod, and a second shell is coaxially arranged on the bearing of the second inner rod; A constant force spring module or at least two parallel-connected constant force spring modules are arranged between the first inner rod and the second inner rod; Each of the constant force spring modules includes a coaxial torsion core, a constant force spring, and a spring cavity; One end of the constant force spring is fixed on the torsion core, and the other end is fixed on the spring cavity; The first inner rod and the second inner rod are respectively coaxial with and detachably connected to the adjacent torsion cores, and the first shell and the second shell are respectively coaxial with and detachably connected to the adjacent spring cavities.

[0005] A clamping hook extending axially from the end of the spring cavity is arranged at one end of the shell of the spring cavity; A clamping groove is arranged on the outer circumference of the spring cavity corresponding to the position of the clamping hook of the adjacent spring cavity; The adjacent spring cavities are connected together through the cooperation of the clamping hook and the clamping groove.

[0006] A clamping groove for cooperating with a clamping hook of an adjacent spring cavity is provided at the right end of the first housing, a clamping hook for cooperating with a clamping groove of an adjacent spring cavity is provided at the left end of the second housing, a clamping hook is provided on the left side of the spring cavity and a clamping groove is provided on the right side; or a clamping hook for cooperating with a clamping groove of an adjacent spring cavity is provided at the right end of the first housing, a clamping groove for cooperating with a clamping hook of an adjacent spring cavity is provided at the left end of the second housing, a clamping groove is provided on the left side of the spring cavity and a clamping hook is provided on the right side.

[0007] A fixing rod with the same axis of rotation is fixedly arranged between the first inner rod and the second inner rod, and the torsion core is slidably sleeved on the fixing rod; no relative rotation occurs between the torsion core and the fixing rod; axial contact occurs between adjacent torsion cores, between the left-end torsion core and the first inner rod, and between the right-end torsion core and the second inner rod.

[0008] The inner cavity of the spring is a cylindrical shape with a through hole in the middle, a positioning ring is provided at the right end of the torsion core, and the positioning ring is arranged on the left side of the right-end housing of the spring torsion core to limit the left position of the spring torsion core.

[0009] An expansion rod is provided at the left end of the first inner rod, the expansion rod axially slides and is non-rotatably arranged in the first inner rod, and an elastic buffer is arranged between the expansion rod and the first inner rod.

[0010] A sliding hole is provided in the first inner rod, the right end of the expansion rod is arranged in the sliding hole, and the elastic buffer is arranged between the expansion rod and the bottom surface of the sliding hole; a limiting long groove is provided on the circumferential surface of the expansion rod, and the length direction of the limiting long groove is axial; pin holes are provided on the first inner rod and the first housing, and a limiting pin passing through the pin hole and reaching the limiting long groove is arranged in the pin hole.

[0011] A reel for winding and unwinding a curtain is fixedly and coaxially arranged outside the first housing.

[0012] Compared with the prior art, a constant-force spring assembly which is modular and convenient for assembly and disassembly is provided in the present utility model. The constant-force spring specifications are modularized, and bearings are added at both ends to maintain the coaxiality between constant-force spring modules and minimize the loss of spring force caused by friction to the greatest extent, so that customers can independently match modules according to needs to assemble a constant-force spring of the required specification, solving the problems of cumbersome preparatory work and high cost in the debugging of curtain springs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a perspective view (hiding the reel) of an embodiment of the present utility model including multiple spring modules.

[0014] Figure 2 is Figure 1 an exploded view of.

[0015] Figure 3 is Figure 1 a sectional view of...

[0016] Figure 4 is Figure 3 an enlarged view of the connection part of the constant force spring module in...

[0017] Figure 5 a sectional view of the spring cavity

[0018] Figure 6 is an embodiment including a single spring module (showing a partial coiled tube).

[0019] Figure 7 is a graph showing the relationship between the elastic force and the stretching length of constant force spring modules of various specifications

[0020] Figure 8 is an assembly drawing of the constant force spring module

[0021] Figure 9 is an assembly drawing of the first inner rod and the fixed rod [[ID=,31]]

[0022] Figure 10 is a sectional view of the first housing

[0023] Among them, 1 is the telescopic rod, 2 is the compression spring, 3 is the first inner rod, 4 is the bearing, 5 is the first housing, 6 is the fixed rod, 7 is the torsion core, 8 is the spring cavity, 9 is the second inner rod, 10 is the second housing, 11 is the screw, 12 is the constant force spring, and 13 is the limit pin. Specific implementation method

[0024] In the present utility model, unless otherwise clearly defined and limited, the technical terms used in this application should have the ordinary meanings understood by those skilled in the art of the present utility model. Terms such as "connected", "connected to", "fixed", "arranged", etc. should be understood in a broad sense. It can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium; it can be a mechanical connection or an electrical connection. Unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be direct contact between the first and second features, or indirect contact through an intermediate medium. Moreover, the first feature being "above" or "over" or "on top of" the second feature, etc., can mean that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under" or "below" or "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature. Relative terms such as first, second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Terms used in the description such as "center", "lateral", "longitudinal", "length", "width", "thickness", "height", "front", "rear", "left", "right", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0025] The technical solutions of the present utility model will be clearly and completely described below in conjunction with the drawings and specific embodiments. As Figure 1-10As shown, a constant force spring assembly includes a first inner rod 3 disposed at the left end and a second inner rod 9 coaxial with it disposed at the right end; bearings 4 are respectively disposed on the first inner rod 3 and the second inner rod 9. A first housing 5 is coaxially disposed on the bearing 4 of the first inner rod 3, and a second housing 10 is coaxially disposed on the bearing 4 of the second inner rod 9; a constant force spring 12 module or at least two parallel-connected constant force spring 12 modules are disposed between the first inner rod 3 and the second inner rod 9; each of the constant force spring 12 modules includes a coaxial torsion core 7, a constant force spring 12, and a spring cavity 8; one end of the constant force spring 12 is fixed on the torsion core 7 and the other end is fixed on the spring cavity 8; the first inner rod 3 and the second inner rod 9 are respectively coaxial with and detachably connected to the adjacent torsion core 7, and the first housing 5 and the second housing 10 are respectively coaxial with and detachably connected to the adjacent spring cavity 8. The left end and the right end here are only for indicating the relative position relationship. The left end of the bearing 4 of the first inner rod 3 is limited by a shoulder provided on the first inner rod 3, and the right end of the bearing 4 can be limited by the first housing 5. The two ends of the bearing 4 of the second inner rod 9 can be respectively positioned by the adjacent spring cavity 8 and the second housing 10. The present utility model provides a constant force spring 12 assembly that is modular and convenient for assembly and disassembly, modularizes the specifications of the constant force spring 12, and installs bearings 4 at both ends to maintain the coaxiality between the constant force spring 12 modules and minimize the loss of spring force caused by friction to the greatest extent, enabling customers to independently match the modules according to their needs to assemble the constant force spring 12 of the required specifications, and solving the problems of cumbersome preparatory work and high cost in the debugging of curtain springs in the early stage.

[0026] A clamping hook 14 extending axially out of the end of the spring cavity 8 is disposed at one end of the housing of the spring cavity 8; a clamping groove 15 is disposed on the outer circumference of the spring cavity 8 corresponding to the position of the clamping hook 14 of the adjacent spring cavity 8; adjacent spring cavities 8 are connected together through the cooperation of the clamping hook 14 and the clamping groove 15. The shape of the clamping hook 14 only needs to facilitate its slight deformation so as to cross the circumferential surface of a section of the spring cavity 8 to reach the clamping groove 15 of the adjacent spring cavity 8. The material of the clamping hook 14 can be a material such as plastic with certain plasticity and elasticity to facilitate entering the clamping groove 15. Of course, for the convenience of installation, inclined surfaces and limiting surfaces can be respectively disposed at both ends of the clamping hook 14. The inclined surface can be a plane or a curved surface, and the inclined surface is used to cross the end surface of the spring cavity 8. The limiting surface is used to block the reverse movement of the clamping hook 14 so as to prevent it from getting out of the clamping groove 15.

[0027] A clamping groove 15 is provided at the right end of the first housing 5 for cooperating with a clamping hook 14 of an adjacent spring cavity 8, and a clamping hook 14 is provided at the left end of the second housing 10 for cooperating with the clamping groove 15 of the adjacent spring cavity 8. A clamping hook 14 is provided on the left side of the spring cavity 8, and a clamping groove 15 is provided on the right side; or a clamping hook 14 is provided at the right end of the first housing 5 for cooperating with the clamping groove 15 of the adjacent spring cavity 8, a clamping groove 15 is provided at the left end of the second housing 10 for cooperating with the clamping hook 14 of the adjacent spring cavity 8, a clamping groove 15 is provided on the left side of the spring cavity 8, and a clamping hook 14 is provided on the right side. The left and right here are only for indicating the relative positions and the cooperation relationship between the clamping groove 15 and the clamping hook 14, and are not absolute left and right. In the present utility model, the cooperation between the first housing 5 and the spring cavity 8, and between the second housing 10 and the spring cavity 8 also adopts the cooperation mode of the clamping groove 15 and the clamping hook 14, and there are specifically two matching modes. Of course, other cooperation modes can also be adopted between the first housing 5 and the spring cavity 8, and between the second housing 10 and the spring cavity 8, such as common connection structures like screw connection and bolt connection.

[0028] A fixing rod 6 with the same axis of rotation is fixedly arranged between the first inner rod 3 and the second inner rod 9, and the torsion core 7 is slidably sleeved on the fixing rod 6; there is no relative rotation between the torsion core 7 and the fixing rod 6; the adjacent torsion cores 7, between the left-end torsion core 7 and the first inner rod 3, and between the right-end torsion core 7 and the second inner rod 9 are in axial contact. A fixing hole corresponding to the fixing rod 6 is arranged inside the torsion core 7, and the fixing hole is a through hole. The shape of the fixing rod 6 matches the shape of the fixing hole. The shape of the fixing rod 6 can be various, such as the cross-section of the fixing rod 6 being D-shaped, L-shaped, spline-shaped, circular with protrusions or grooves, etc., as long as it can ensure that there is no relative rotation between the fixing rod 6 and the torsion core 7. The first inner rod 3 and the second inner rod 9 can be respectively fixed to both ends of the fixing rod 6 through screws 11. The torsion core 7 is slidably arranged on the fixing rod 6, which is convenient for installation and disassembly. The axial contact here means that there is no axial gap. After installation, there is no axial movement space between the torsion cores 7 of the constant force spring 12 module. A torsion core boss for fixing one end of the constant force spring 12 is arranged on the circumferential surface of the torsion core 7. The connection mode between both ends of the constant force spring 12 and the torsion core 7 and the spring cavity 8 belongs to the prior art and will not be described in detail. Before or after installation, the length of the fixing rod 6 can be cut to a suitable length according to needs. By setting the structure of the fixing rod 6 in the present utility model, compared with the structure without a fixing rod 6 where the adjacent torsion cores 7 are fixedly connected, multiple torsion cores 7 in the present utility model are based on the fixing rod 6, which is easier to ensure the coaxiality of the multiple torsion cores 7 thereon, and also increases the strength inside the constant force spring 12 assembly, and is more suitable for large curtain structures with larger torques.

[0029] The inner cavity of the spring is a cylindrical shape with a through hole in the middle. A positioning ring 71 is provided at the right end of the torsion core 7. The positioning ring 71 is arranged on the left side of the right-end housing of the spring torsion core 7 to limit the left movement of the spring torsion core 7. The limit of the axial movement of the right side of the spring cavity 8 is achieved through the cooperation between the engaging hook 14 and the engaging groove 15. The left limit of the spring cavity 8 can effectively prevent the spring cavity 8 from continuing to move leftward when stressed, resulting in the phenomenon that the engaging hook 14 and the engaging groove 15 are disengaged. In addition, the right end of the inner cavity of the spring and the right end of the corresponding torsion core 7 also play a role in separating adjacent constant-force springs 12.

[0030] A telescopic rod 1 is provided at the left end of the first inner rod 3. The telescopic rod 1 is axially slidable and non-rotatably arranged in the first inner rod 3, and an elastic buffer is provided between the telescopic rod 1 and the first inner rod 3. For curtains without a cover or an upper beam, the curtain needs to be installed horizontally on the curtain bracket. There must be a certain lateral telescopic gap between the curtain body and the curtain bracket. The telescopic rod 1 is fixed to the curtain bracket, and the first inner rod 3 and the entire constant-force spring 12 assembly are fixed to the curtain body. Therefore, the axial distance between the telescopic rod 1 and the first inner rod 3 needs to be telescopic, that is, it can vary within a certain range. The telescopic rod 1 may not be provided at the left end of the first inner rod 3, which is applicable to conventional curtains with a cover. The cross-section of the telescopic rod 1 is preferably rectangular, or it can also be other shapes that are not convenient to rotate.

[0031] The first inner rod 3 is provided with a sliding hole. The right end of the telescopic rod 1 is arranged in the sliding hole, and the elastic buffer is provided between the telescopic rod 1 and the bottom surface of the sliding hole; a limiting long groove 17 is provided on the circumferential surface of the telescopic rod 1, and the length direction of the limiting long groove 17 is axial; pin holes are provided on the first inner rod 3 and the first housing 5, and a limiting pin 13 passing through the pin hole and reaching the limiting long groove 17 is arranged in the pin hole. The limiting pin 13 is used to fix the axial positions of the telescopic rod 1 and the first inner rod 3, ensuring that the telescopic rod 1 only axially moves within the length range of the limiting long groove 17. The limiting pin 13 also fixes the axial positions of the first inner rod 3 and the first housing 5. The elastic buffer can be a compression spring 2, and the compression spring 2 ensures that the telescopic rod 1 and the first inner rod 3 are in a compressed state axially. The limiting long groove 17 can be a through hole or a blind hole. In the structure of the attached drawing, the limiting long groove 17 is a through groove, and a long limiting pin 13 passes through the first outer shell, the first inner rod 3, and the telescopic rod 1 to fix the axial positions of these three. A spring hole is provided inside the right end of the telescopic rod 1 to facilitate the placement of the spring therein.

[0032] The outside of the first housing 5 is fixedly and coaxially provided with a reel 16 for retracting and extending a curtain. One end of the curtain fabric is connected to the reel 16, and the reel 16 rotates forward and backward when the curtain fabric is retracted. In the utility model, the first housing 5, the second housing 10, and the spring cavity 8 are fixedly arranged inside the reel 16 and rotate along with the reel 16. The first inner rod 3, the second inner rod 9, the fixed rod 6, and the torsion core 7 thereon are fixed by the telescopic rod 1 and the curtain bracket and do not rotate along with the reel 16.

[0033] Working principle: The elastic forces of the respective spring modules can be the same or different. For example, there are four specifications, namely No. 1, No. 2, No. 3, and No. 4, corresponding to the torques required for curtain systems with widths of 10, 20, 30, and 40 cm respectively. The spring modules have corresponding initial torques to provide the torques required for the tube and the lower beam in the curtain system. The spring torque change coefficient is consistent with the midline coefficient of the corresponding width, and for the same stretching length, the torque of the latter specification module is twice that of the former specification module. The spring modules provide torques consistent with the requirements for retracting and extending the curtain, ensuring stable and smooth retraction and extension of the curtain. During the curtain debugging process, for curtain systems with widths greater than 40 cm, they can be adapted by modules composed of four specifications of modules. For widths within the corresponding ranges of two specifications, use the module of the larger specification. For example, for a 32-cm-wide curtain, use the convenient spring of the No. 4 module; for a 52-cm-wide curtain, use the convenient spring of the module corresponding to a 60-cm-wide curtain. The differences in torques required for different types of tubes and lower beams can be adjusted by increasing or decreasing the counterweights. For tubes and lower beams that are too heavy, the initial torque of the convenient spring can also be increased by pre-tightening. For example, to adjust a 70-cm-wide curtain, a module composed of the No. 3 and No. 4 spring modules or a module composed of the No. 1, No. 2, and No. 4 spring modules can be used, etc. The combination is flexible and the operation is convenient. The torque of the module is the sum of the torques of the modules within the module. When the curtain rebounds due to the tube and the lower beam being too light in weight due to reasons such as the shape and material of the tube and the lower beam, counterweights can be added to the lower beam. When the curtain cannot be retracted due to the tube and the lower beam being too heavy, the module can be pre-tightened to increase the initial torque of the convenient spring.

[0034] Assemble the left-end telescopic rod 1 and the bearing 4: Place the spring into the spring hole at the right end of the telescopic rod 1, align the sliding hole of the first inner rod 3 with the telescopic rod 1 and move it leftward to install it on the telescopic rod 1. Install the bearing 4 on the first inner rod 3. Insert the fixed rod 6 into the D-shaped groove at the right end of the first inner rod 3 and fix it with the side screw 11. Install the bearing 4 assembly at the left end into the first housing 5, and insert the limit pin 13 to restrict the first housing 5, the first inner rod 3, and the telescopic rod 1.

[0035] When assembling the spring module: Hook the straight notch at the center end of the constant force spring 12 onto the boss of the torsion core 7 and rotate it 90 degrees to prevent detachment. The other end is snapped into the groove of the spring cavity 8. The right end of the torsion core 7 is inserted into the central circular hole of the spring cavity 8 for positioning. The left end is inserted into the central circular hole of the left docking spring cavity 8 or the central circular hole of the first housing 5 for positioning. The left end of the spring cavity 8 is used to snap onto the top boss of the left docking part, and the engaging hook 14 is snapped into the engaging groove 15 of the docking part for complete restraint. The engaging groove 15 and the top boss on the spring cavity 8 are restrained by the right docking part.

[0036] Insert the torsion core 7 of the assembled spring module into the fixed rod 6, and the fixed rod 6 restrains the torsion core 7. The left and right ends of the torsion cores 7 and the spring cavities 8 of multiple spring modules are respectively restrained by the positioning and engaging structures. After the spring module is assembled, the end of the fixed rod 6 is inserted into the D-shaped through hole of the second inner rod 9 and fixed by the side screw 11 to restrain the second inner rod 9. The part of the fixed rod 6 extending out of the D-shaped through hole can be removed by a tool. A bearing 4 is installed on the second inner rod 9 and then inserted into the second housing 10. The right end of the second inner rod 9 is inserted into the central circular hole of the second housing 10 for positioning, and the axis is aligned through the conical part. The left end is inserted into the central circular hole of the docking spring inner cavity for positioning. The left end of the second cavity snaps onto the top boss of the docking part, and the engaging hook snaps into the engaging groove 15 of the docking part for complete restraint. The NKI1520 bearing 4 on it cooperates with the NKI1520 bearing 4 on the first inner rod 3 to support the fixed rod 6 and radially and axially position the shaft rotating relative to other components such as the bearing 4 seat, ensuring the coaxiality between modules.

[0037] The utility model connects the axes of each module in series through the fixed rod 6, enabling the axes to rotate synchronously, ensuring the synchronization rate of each spring module. When using the modular and convenient constant force spring 12, the descending heights of each spring module are the same, preventing deformation problems caused by individual spring modules exceeding the maximum stroke of the spring.

[0038] The technical features of the above-described embodiments can be combined arbitrarily. As long as there is no contradiction in the combination of these technical features, it should be considered within the scope described in this specification. Without departing from the overall concept of the utility model, any changes and improvements made by equivalent replacement or modification based on the technical solution of the utility model should also be regarded as within the protection scope of the utility model.

Claims

1. A constant force spring assembly, characterized in that: It includes a first inner rod arranged at the left end and a second inner rod arranged coaxially at the right end; bearings are respectively arranged on the first inner rod and the second inner rod, and a first housing is coaxially arranged on the bearing of the first inner rod, and a second housing is coaxially arranged on the bearing of the second inner rod; a constant force spring module or at least two parallel-connected constant force spring modules are arranged between the first inner rod and the second inner rod; each of the constant force spring modules includes a coaxial torsion core, a constant force spring and a spring cavity; one end of the constant force spring is fixed on the torsion core and the other end is fixed on the spring cavity; the first inner rod and the second inner rod are respectively coaxial with and detachably connected to the adjacent torsion cores, and the first housing and the second housing are respectively coaxial with and detachably connected to the adjacent spring cavities.

2. The constant force spring assembly according to claim 1, wherein: A clamping hook extending axially out of the end of the spring cavity is arranged at one end of the housing of the spring cavity; a clamping groove is arranged on the outer circumference of the spring cavity corresponding to the position of the clamping hook of the adjacent spring cavity; the adjacent spring cavities are connected together through the cooperation of the clamping hook and the clamping groove.

3. The constant force spring assembly according to claim 2, characterized in that: A clamping groove for cooperating with the clamping hook of the adjacent spring cavity is arranged at the right end of the first housing, a clamping hook for cooperating with the clamping groove of the adjacent spring cavity is arranged at the left end of the second housing, a clamping hook is arranged on the left side of the spring cavity and a clamping groove is arranged on the right side; or a clamping hook for cooperating with the clamping groove of the adjacent spring cavity is arranged at the right end of the first housing, a clamping groove for cooperating with the clamping hook of the adjacent spring cavity is arranged at the left end of the second housing, a clamping groove is arranged on the left side of the spring cavity and a clamping hook is arranged on the right side.

4. The constant force spring assembly according to claim 1, wherein: A fixed rod with the same axis of rotation is fixedly arranged between the first inner rod and the second inner rod; the torsion core is slidably sleeved on the fixed rod; there is no relative rotation between the torsion core and the fixed rod; the adjacent torsion cores, the left torsion core and the first inner rod, and the right torsion core and the second inner rod are in axial contact.

5. The constant force spring assembly according to claim 3, wherein: The inner cavity of the spring is a cylindrical shape with a through hole in the middle, a positioning ring is arranged at the right end of the torsion core, and the positioning ring is arranged on the left side of the right-end housing of the spring torsion core to limit the torsion core to the left.

6. The constant force spring assembly according to any one of claims 1-5, characterized in that: An expansion rod is arranged at the left end of the first inner rod, and the expansion rod axially slides and is non-rotatably arranged in the first inner rod and an elastic buffer is arranged between the expansion rod and the first inner rod.

7. The constant-force spring assembly according to claim 6, wherein: A sliding hole is arranged on the first inner rod, the right end of the expansion rod is arranged in the sliding hole, and the elastic buffer is arranged between the expansion rod and the bottom surface of the sliding hole; a limiting long groove is arranged on the circumferential surface of the expansion rod, and the length direction of the limiting long groove is axial; pin holes are arranged on the first inner rod and the first housing, and a limiting pin passing through the pin hole and reaching the limiting long groove is arranged in the pin hole.

8. The constant force spring assembly according to any one of claims 1-5, characterized in that: A winding tube for winding and unwinding the curtain is fixedly and coaxially arranged outside the first housing.

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