Double-curtain linkage limiting structure and curtain

Abstract

The utility model relates to a window curtain technical field discloses a kind of double curtain cloth linkage limiting structure and window curtain, including upper beam track, middle rail, lower rail and the first pull cord assembly being set on upper beam track, first curtain cloth is set between middle rail and lower rail, second curtain cloth is set between upper beam track and middle rail, first screw rod and second screw rod are set on upper beam track, first limiting nut is threadedly connected on first screw rod, the one end of first screw rod is provided with first limiting block, second limiting nut is threadedly connected on second screw rod.The utility model is positioned to first screw rod and second screw rod by first limiting nut, second limiting nut respectively, so that middle rail and lower rail are positioned in respective lower limit position, avoid the problem that curtain rope reverse winding is caused due to excessive operation in curtain cloth lowering process;First screw rod and second screw rod can be linked simultaneously, avoid second curtain cloth to lower excessively and interfere with first curtain cloth, and use experience is good.

Description

Technical Field

[0001] This utility model relates to the field of curtain technology, and more specifically, to a double curtain linkage limiting structure. Background Technology

[0002] Day and night blinds, a type of curtain product that combines light transmission and blackout functions, typically consist of two pieces of fabric: a light-transmitting fabric (allowing some light to pass through) and a blackout fabric (opaque). Each piece is raised and lowered independently via a separate beaded cord control system to meet the user's needs for both light and privacy at different times of day. These products are widely used in homes and offices.

[0003] However, existing day and night blind products generally suffer from the following technical defects: When the curtain descends to its lower limit, if the user continues to pull the cord excessively in the downward direction, the winding drum will reverse, causing the curtain to rise instead of descend, affecting the user experience. Furthermore, the light-transmitting and blackout curtains are usually arranged side-by-side on the same vertical plane, and the two lifting control systems (such as beaded cords and winding mechanisms) operate independently, lacking necessary mechanical linkage and limiting mechanisms. This structural design means that when the user operates either curtain, the system cannot constrain the relative position of the other curtain. Therefore, improper operation or visual errors can easily cause one curtain to rise or fall excessively, resulting in spatial collision and mechanical interference with another curtain that is stationary.

[0004] This interference not only generates noise and affects the appearance of the curtains, but can also cause wrinkles, deformation, and even damage to key components of the lifting mechanism, shortening the product's lifespan. Furthermore, this defect forces users to constantly visually observe the relative positions of the two curtains and adjust them carefully to avoid interference. This significantly reduces the product's usability, making "blind operation" (i.e., convenient operation without visual cues) difficult to achieve, resulting in a poor user experience. Therefore, there is an urgent need in this field for a new day and night curtain structure that can effectively solve the above problems by introducing a linkage limiting mechanism to fundamentally prevent interference between the two curtains, thereby improving operational convenience and product reliability. Utility Model Content

[0005] To address at least one of the aforementioned problems, this utility model provides a double-curtain linkage limiting structure, comprising an upper beam track, a middle track, a lower track, and a first pull rope assembly disposed on the upper beam track. A first curtain is disposed between the middle track and the lower track, and a second curtain is disposed between the upper beam track and the middle track. A first screw and a second screw are disposed on the upper beam track. A first limiting nut is threaded onto the first screw, and a first limiting block is disposed at one end of the first screw. A second limiting nut is threaded onto the second screw, and a second limiting block is disposed at one end of the second screw. A rotating sleeve is rotatably sleeved on the outer side of the second screw, and the second limiting nut is slidably sleeved on the inner side of the rotating sleeve along the axial direction of the rotating sleeve. The device is equipped with a first gear, and a second gear meshing with the first gear is provided on the rotating sleeve. When the second curtain has been pulled up a certain distance and the first curtain needs to be pulled up, the first screw drives the rotating sleeve to rotate through the meshing of the first and second gears. The rotating sleeve drives the second limiting nut to rotate, thereby pulling up the first curtain. This invention limits the first and second screws with the first and second limiting nuts, respectively, so that the middle and lower rails are limited at their respective lower limit positions, avoiding the problem of the curtain rope rewinding in reverse due to excessive operation during the curtain lowering process. At the same time, the first and second screws can be linked to prevent the second curtain from being lowered too much and interfering with the first curtain, resulting in a better user experience.

[0006] Optionally, the second limiting nut is provided with a first limiting protrusion, and the rotating sleeve is provided with a first limiting groove along its own axial direction, and the first limiting protrusion is slidably placed in the first limiting groove.

[0007] Optionally, one end of the first limiting nut is provided with a first protruding tooth, and the first limiting block is provided with a first groove corresponding to the first protruding tooth; one end of the second limiting nut is provided with a second protruding tooth, and the second limiting block is provided with a second groove corresponding to the second protruding tooth.

[0008] Optionally, the first curtain is made of a light-transmitting material and the second curtain is made of a light-blocking material; or, the first curtain is made of a light-blocking material and the second curtain is made of a light-transmitting material.

[0009] Optionally, the double-curtain linkage limiting structure further includes a second pull cord assembly. The first pull cord assembly includes a first pull cord, and the second pull cord assembly includes a second pull cord. The first pull cord is provided with a first upward pull portion and a first downward pull portion, and the second pull cord is provided with a second upward pull portion and a second downward pull portion. The first curtain and the second curtain are located on the same vertical plane. In use, by pulling the first upward pull portion, the second screw is rotated in the opposite direction to move the middle rail upward. By pulling the first downward pull portion, the second screw is rotated in the forward direction to move the middle rail downward. By pulling the second upward pull portion, the first screw is rotated in the opposite direction to move the lower rail upward. By pulling the second downward pull portion, the first screw is rotated in the forward direction to move the lower rail downward.

[0010] Optionally, the upper beam track is provided with a first rotating shaft and a second rotating shaft. The first rotating shaft is connected to the first screw and rotates synchronously. The second rotating shaft is connected to the second screw and rotates synchronously. The first rotating shaft is provided with a first rope drum. A first curtain rope is connected between the first rope drum and the first curtain fabric. The second rotating shaft is provided with a second rope drum. A second curtain rope is connected between the second rope drum and the second curtain fabric.

[0011] Optionally, a wire groove is provided between the first and second rope drums, through which both the first and second curtain ropes pass. The upper beam track is provided with a first turntable for installing the second pull rope and a second turntable for installing the first pull rope. A third gear that rotates synchronously with the first turntable is provided on one side of the first turntable, and a fourth gear that meshes with the third gear is connected to one end of the first rotating shaft. The second pull rope and the first pull rope are respectively provided on both sides of the upper beam track, wherein the first pull rope is a first beaded rope and the second pull rope is a second beaded rope.

[0012] Optionally, the second pull rope assembly includes a first reduction transmission mechanism disposed between the fourth gear and the first rotating shaft. The first reduction transmission mechanism includes a first connecting column, a second connecting column, a third connecting column, and a first housing. The second connecting column is connected between the first connecting column and the third connecting column. One end of the first connecting column is connected to the fourth gear, and the other end of the first connecting column is provided with a first connecting block. The end of the second connecting column near the first connecting column is provided with a second connecting block. Two first mounting slots are provided between the first connecting block and the second connecting block. A first clamping spring is sleeved on the outer side of the first connecting block and the second connecting block. The first clamping spring is provided with a first support leg and a second support leg. The first support leg is placed in one of the first mounting slots, and the second support leg is placed in the other first mounting slot. The third connecting column is connected to the first rotating shaft. A first planetary carrier is provided on the third connecting column. A plurality of first planetary gears are provided on the first planetary carrier. The first housing is fixedly connected to the upper beam track. A first sun gear is provided on the second connecting column. A first gear ring is provided on the inner side of the first housing. The first planetary gears are simultaneously connected to the first sun gear. The first gear ring engages with the first pull rope assembly; the first pull rope assembly includes a second reduction transmission mechanism, the second reduction transmission mechanism includes a fourth connecting post, a fifth connecting post, a sixth connecting post, and a second housing, the fifth connecting post being connected between the fourth connecting post and the sixth connecting post, one end of the fourth connecting post being connected to the second turntable, the other end of the fourth connecting post being provided with a third connecting block, the end of the fifth connecting post near the fourth connecting post being provided with a fourth connecting block, two second mounting slots being provided between the third connecting block and the fourth connecting block, and the outer sides of the third connecting block and the fourth connecting block being provided with a second... Two clamping springs, each with a third and a fourth support leg, the third support leg being placed in one of the second mounting slots and the fourth support leg being placed in the other. A sixth connecting column is connected to the second rotating shaft, and a second planetary carrier is mounted on the sixth connecting column. The second planetary carrier has several second planetary gears. The second housing is fixedly connected to the upper beam track. A second sun gear is mounted on the fifth connecting column, and a second gear ring is mounted on the inner side of the second housing. The second planetary gears mesh with both the second sun gear and the second gear ring.

[0013] Optionally, a limiting sleeve is detachably provided on the outside of the first limiting nut, and a second limiting protrusion is provided on the outside of the first limiting nut. A second limiting groove is provided on the inner side of the limiting sleeve along its own axial direction. The second limiting protrusion is placed in the second limiting groove for limiting. An inner sidewall is provided on the upper beam track, and an abutment block is provided on the side of the limiting sleeve near the inner sidewall. In use, the abutment block abuts against the inner sidewall to restrict the circumferential rotation of the limiting sleeve and the first limiting nut relative to the upper beam track.

[0014] Compared to existing technologies, the double curtain linkage limiting structure in this utility model limits the first screw and the second screw by using the first limiting nut and the second limiting nut respectively, so that the middle rail and the lower rail are limited at their respective lower limit positions, avoiding the problem of the curtain rope rewinding in reverse due to excessive operation during the curtain lowering process; at the same time, the first screw and the second screw can be linked to prevent the second curtain from being lowered too much and interfering with the first curtain, resulting in a better user experience.

[0015] In addition, this utility model also provides a curtain, including the above-mentioned double curtain linkage limiting structure. This curtain also has the beneficial effects of the above-mentioned double curtain linkage limiting structure, which will not be described in detail here. Attached Figure Description

[0016] Figure 1 This is a perspective view of the double-curtain linkage limiting structure of this utility model;

[0017] Figure 2 This is a schematic diagram of the upper beam track part of the double curtain linkage limiting structure of this utility model;

[0018] Figure 3 for Figure 2 Enlarged view of section A;

[0019] Figure 4 This is a schematic diagram of the first rope drum of the double curtain linkage limiting structure of this utility model;

[0020] Figure 5 This is a cross-sectional view of the double curtain linkage limiting structure of this utility model when the first curtain is at the first lower limit position and the second curtain is at the second lower limit position.

[0021] Figure 6 This is an exploded view of the double-curtain linkage limiting structure of this utility model;

[0022] Figure 7 This is a schematic diagram of the rotating sleeve of the double curtain linkage limiting structure of this utility model;

[0023] Figure 8 This is a schematic diagram of the deceleration transmission mechanism of the double curtain linkage limiting structure of this utility model;

[0024] Figure 9 This is an exploded view of the deceleration transmission mechanism of the double curtain linkage limiting structure of this utility model;

[0025] Figure 10 This is a schematic diagram of the first housing of the double curtain linkage limiting structure of this utility model;

[0026] Figure 11 This is a schematic diagram of the second turntable part of the double curtain linkage limiting structure of this utility model;

[0027] Figure 12 This is a schematic diagram of the limiting sleeve part of the double curtain linkage limiting structure of this utility model;

[0028] Figure 13 This is a schematic diagram of the first pull rope assembly of the double curtain linkage limiting structure of this utility model;

[0029] Figure 14 This is a schematic diagram of the second housing of the double curtain linkage limiting structure of this utility model;

[0030] The component names corresponding to the various labels in the attached figures are as follows: 1 is the upper beam track, 100 is the mounting base, 101 is the inner sidewall, 2 is the middle rail, 3 is the lower rail, 4 is the first curtain fabric, 5 is the second curtain fabric, 6 is the first screw, 601 is the first limiting block, 6011 is the first slot, 602 is the first gear, 7 is the second screw, 701 is the second limiting block, 7011 is the second slot, 8 is the second pull rope, 81 is the second upper pull part, 82 is the second lower pull part, 9 is the first pull rope, and 90 is the first pull rope. Components: 91 is the first pull-up part, 92 is the first pull-down part, 10 is the first limiting nut, 1001 is the first protruding tooth, 1002 is the second limiting protrusion, 11 is the second limiting nut, 1101 is the first limiting protrusion, 1102 is the second protruding tooth, 12 is the rotating sleeve, 1201 is the second gear, 1202 is the first limiting groove, 13 is the first rotating shaft, 14 is the second rotating shaft, 15 is the first rope drum, 16 is the first curtain rope, 17 is the second rope drum, 18 is the second curtain rope, 19 is the... 20 is the first turntable, 21 is the second turntable, 22 is the third gear, 23 is the fourth gear, 24 is the limiting sleeve, 2401 is the second limiting groove, 2402 is the abutment block, 25 is the first connecting post, 2501 is the first connecting block, 26 is the second connecting post, 2601 is the second connecting block, 27 is the third connecting post, 28 is the first housing, 2801 is the first gear ring, 29 is the first planetary carrier, 30 is the first planetary gear, 31 is the first sun gear, 32 is the first clamping spring, 3 201 is the first support leg, 3202 is the second support leg, 33 is the bolt, 34 is the first mounting slot, 35 is the fourth connecting post, 3501 is the third connecting block, 36 is the fourth connecting post, 3601 is the fourth connecting block, 37 is the sixth connecting post, 38 is the second housing, 3801 is the second gear ring, 39 is the second mounting slot, 40 is the second clamping spring, 4001 is the third support leg, 4002 is the fourth support leg, 41 is the second planetary carrier, 42 is the second planetary gear, and 43 is the second sun gear. Detailed Implementation

[0031] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0032] In the description of this utility model, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship when the product is in normal use.

[0033] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0034] See Figures 1-14 This utility model embodiment provides a double-curtain linkage limiting structure, including an upper beam track 1, a middle track 2, a lower track 3, and a first pull rope assembly 90 disposed on the upper beam track 1. A first curtain 4 is disposed between the middle track 2 and the lower track 3, and a second curtain 5 is disposed between the upper beam track 1 and the middle track 2. A first screw 6 and a second screw 7 are disposed on the upper beam track 1. A first limiting nut 10 is threaded onto the first screw 6, and a first limiting block 601 is disposed at one end of the first screw 6. A second limiting nut 11 is threaded onto the second screw 7, and a second limiting block 701 is disposed at one end of the second screw 7. A rotating sleeve 12 is rotatably sleeved on the outer side of the second screw 7, and the second limiting nut 11 is slidably sleeved on the inner side of the rotating sleeve 12 along the axial direction of the rotating sleeve 12. A first gear 602 is disposed on the first screw 6. The rotating sleeve 12 is equipped with a second gear 1201 that meshes with the first gear 602. When the second curtain 5 has been pulled up a certain distance and the first curtain 4 needs to be pulled up, the first screw 6 drives the rotating sleeve 12 to rotate through the meshing of the first gear 602 and the second gear 1201. The rotating sleeve 12 drives the second limiting nut 11 to rotate, thereby realizing the pulling up of the first curtain 4. This utility model limits the first screw 6 and the second screw 7 by the first limiting nut 10 and the second limiting nut 11, respectively, so that the middle rail 2 and the lower rail 3 are limited at their respective lower limit positions, avoiding the problem of the curtain rope reversing due to excessive operation during the curtain lowering process. At the same time, the first screw 6 and the second screw 7 can be linked to prevent the second curtain 5 from being lowered too much and interfering with the first curtain 4, resulting in a better user experience.

[0035] Specifically, in this embodiment, a first limiting nut 10 and a second limiting nut 11, which can move axially with the rotation of the screws, are respectively provided on the first screw 6 and the second screw 7. The displacement of the nuts is rigidly blocked by the limiting block at the end of the screw, so that the middle rail 2 and the lower rail 3 can be reliably locked when they reach the preset lower limit position, avoiding the problem of the curtain rope rewinding in reverse and the curtain fabric rising instead of falling due to excessive pulling. The mechanical linkage between the first screw 6 and the second screw 7 is realized by the meshing of the first gear 602 on the first screw 6 and the second gear 1201 on the rotating sleeve. This ensures that during operation, the lowering stroke of the second curtain fabric 5 is constrained by the position of the first curtain fabric 4, avoiding collision between the two curtain fabrics when descending, ensuring smooth and coordinated operation, and significantly improving the reliability of the product and the user experience.

[0036] Furthermore, in use, the lower rail 3 has a first lower limit position and the middle rail 2 has a second lower limit position. When the lower rail 3 is at the first lower limit position and the middle rail 2 is at the second lower limit position, the first limiting nut 10 abuts against the upper limit of the first limiting block 601 to restrict the first screw 6 from rotating forward and causing the lower rail 3 to move downward, thus restricting the first curtain 4 from falling down. At the same time, the second limiting nut 11 abuts against the upper limit of the second limiting block 701 to restrict the second screw 7 from rotating forward and causing the middle rail 2 to move downward, thus restricting the second curtain 5 from falling down. When it is necessary to pull the second curtain 5 up, external force drives the second screw 7 to rotate in the opposite direction through the first pull rope assembly 90. The second screw 7 drives the second limiting nut 11 to disengage from the second limiting block 701 a certain distance. At the same time, the second screw 7 drives the middle rail 2 to move upward and pulls the second curtain 5 up. After the external force is removed, the second screw is locked by the first pull rope assembly 90. 7; When it is necessary to pull up the first curtain 4, the first screw 6 is driven to rotate in the opposite direction by external force. The first screw 6 drives the first limiting nut 10 to disengage from the first limiting block 601. At the same time, the first screw 6 drives the lower rail 3 to move up and pull up the first curtain 4. The first screw 6 drives the rotating sleeve 12 to rotate through the meshing of the first gear 602 and the second gear 1201. The rotating sleeve 12 drives the second limiting nut 11 to rotate synchronously and approach the second limiting block 701 to realize the pull up of the first curtain 4. When the second limiting nut 11 abuts against the upper limit of the second limiting block 701, the second limiting nut 11 restricts the first screw 6 to rotate in the opposite direction through the rotating sleeve 12 to restrict the pull up of the first curtain 4. At this time, the first curtain 4 is located at the upper limit position that can be pulled up. The upper limit position of the first curtain 4 depends on the pull up position of the second curtain 5. The first curtain 4 can be adjusted between the upper limit position and the first lower limit position as needed.

[0037] See Figures 5-7 The second limiting nut 11 is provided with a first limiting protrusion 1101, and the rotating sleeve 12 is provided with a first limiting groove 1202 along its own axial direction. The first limiting protrusion 1101 is slidably placed in the first limiting groove 1202. The first limiting protrusion 1101 is stuck in the first limiting groove 1202, so that the rotational movement of the rotating sleeve 12 can be effectively transmitted to the second limiting nut 11, so as to drive the second limiting nut 11 to rotate synchronously.

[0038] See Figure 5 , Figure 6 , Figure 7 and Figure 12The first limiting nut 10 has a first protruding tooth 1001 at one end, and the first limiting block 601 has a first slot 6011 corresponding to the first protruding tooth 1001. When the first limiting nut 10 and the first limiting block 601 abut against each other for limiting, the first protruding tooth 1001 engages with the first slot 6011, making the limiting more stable and improving the reliability and stability of the limiting function. The second limiting nut 11 has a second protruding tooth 1102 at one end, and the second limiting block 701 has a second slot 7011 corresponding to the second protruding tooth 1102. When the second limiting nut 11 and the second limiting block 701 abut against each other for limiting, the second protruding tooth 1102 engages with the second slot 7011, making the limiting more stable and improving the reliability and stability of the limiting function.

[0039] See Figure 1 The first curtain 4 is made of a light-transmitting material, and the second curtain 5 is made of a light-blocking material; or, the first curtain 4 is made of a light-blocking material, and the second curtain 5 is made of a light-transmitting material. In this embodiment, the light-transmitting material can be fiber, glass yarn, yarn, etc.; the light-blocking material can be light-blocking linen, high-density polyester, nylon, etc. One curtain is made of a light-transmitting material, and the other curtain is made of a light-blocking material. The corresponding curtain can be unfolded for use as needed to meet the needs of daytime and nighttime use. For example, when a little sunlight needs to be allowed into the room during the day, the light-transmitting curtain can be unfolded for use; at night, the light-blocking curtain can be unfolded for use to ensure privacy. In this embodiment, both the first curtain 4 and the second curtain 5 are honeycomb curtains.

[0040] See Figure 1 , Figure 4 , Figure 5 , Figure 8 and Figure 11 The double-curtain linkage limiting structure also includes a second pull cord assembly. The first pull cord assembly 90 includes a first pull cord 9, and the second pull cord assembly includes a second pull cord 8. The first pull cord 9 is provided with a first upward pull part 91 and a first downward pull part 92, and the second pull cord 8 is provided with a second upward pull part 81 and a second downward pull part 82. The first curtain 4 and the second curtain 5 are located on the same vertical plane. In use, by pulling the first upward pull part 91, the second screw 7 is rotated in the opposite direction to move the middle rail 2 upward. By pulling the first downward pull part 92, the second screw 7 is rotated in the forward direction to move the middle rail 2 downward. By pulling the second upward pull part 81, the first screw 6 is rotated in the opposite direction to move the lower rail 3 upward. By pulling the second downward pull part 82, the first screw 6 is rotated in the forward direction to move the lower rail 3 downward. The second curtain 5 and the first curtain 4 are operated by the first pull cord 9 and the second pull cord 8 respectively, which is convenient to operate.

[0041] Specifically, when the lower rail 3 is at the first lower limit position and the middle rail 2 is at the second lower limit position, the first limiting nut 10 abuts against the upper limit of the first limiting block 601, restricting the forward rotation of the first limiting nut 10. This locks the second pull-down part 82, preventing it from pulling down further. Simultaneously, the second limiting nut abuts against the upper limit of the second limiting block 701, which, through the rotating sleeve 12, restricts the reverse rotation of the first limiting nut 10. This prevents the lower rail 3 from moving upwards, and both the second pull-up part 81 and the second pull-down part 82 cannot be pulled, preventing user misoperation. At this point, the first pull-up part 91 needs to be pulled to drive the second screw 7 to rotate in the opposite direction, causing the middle rail 2 to move upwards. The second limiting nut 11 then moves away from the second limiting block 701. Pulling the second pull-up part 81 again then moves the lower rail 3 upwards. Pulling the second pull-up part 81 moves the lower rail 3 upwards until it is close to the middle rail 2. During the process, the first screw 6 drives the second gear 1201 and the rotating sleeve 12 to rotate through the first gear 602. The rotating sleeve 12 drives the second limiting nut 11 to move towards the second limiting block 701. When the lower rail 3 moves up to a position close to the middle rail 2, the second limiting nut 11 abuts against the second limiting block 701 to limit it. At this time, the second limiting nut 11 and the rotating sleeve 12 cannot continue to rotate. Thus, the rotating sleeve 12 restricts the first screw 6 from continuing to rotate, thereby locking the second pull-up part 81 and the first pull-down part 92 so that they cannot be pulled further. This avoids the second pull-up part 81 and the first pull-down part 92 from being pulled too much, causing interference or damage between the lower rail 3 and the middle rail 2 (the first curtain 4 and the second curtain 5), thus improving the reliability of use. If it is necessary to continue to move the lower rail 3 up, the first pull rope 9 must be pulled first to move the middle rail 2 up to leave room for the lower rail 3 to move up, and then the second pull rope 8 must be pulled to move the lower rail 3 up to the required position.

[0042] See Figure 1 and Figure 4 The upper beam track 1 is provided with a first rotating shaft 13 and a second rotating shaft 14. The first rotating shaft 13 is connected to the first screw 6 and rotates synchronously. The second rotating shaft 14 is connected to the second screw 7 and rotates synchronously. The first rotating shaft 13 is provided with a first rope drum 15. The first rope drum 15 is connected to the first curtain 4 with a first curtain rope 16. The second rotating shaft 14 is provided with a second rope drum 17. The second rope drum 17 is connected to the second curtain 5 with a second curtain rope 18. The rotational motion of the first screw 6 and the second screw 7 is converted into the actual lifting motion of the curtain through the first rope drum 15 and the second rope drum 17.

[0043] See Figure 1 , Figure 4 and Figure 8A groove 19 is provided between the first rope drum 15 and the second rope drum 17. The first curtain rope 16 and the second curtain rope 18 both pass through the groove 19, which restrains the first curtain rope 16 and the second curtain rope 18 within the groove 19, preventing them from becoming tangled and ensuring smooth operation. The upper beam track 1 is provided with a first turntable 20 for installing the second pull rope 8 and a second turntable 21 for installing the first pull rope 9. A third gear 22 that rotates synchronously with the first turntable 20 is provided on one side of the first turntable 20. One end of the first rotating shaft 13 is connected to a fourth gear 23 that meshes with the third gear 22. The second pull rope 8 and the first pull rope 9 are respectively provided on both sides of the upper beam track 1. The first pull rope 9 is the first pull bead rope, and the second pull rope 8 is the second pull bead rope. Through the meshing transmission of the third gear 22 and the fourth gear 23, the rotation direction of the first rotating shaft 13 can be changed, so that the second pull part 81 that pulls the second pull rope 8 and the first pull part 91 that pulls the first pull rope 9 can be changed. At the same time, both drums perform the action of winding up the curtain, thus uniformly realizing the operation logic of "pulling up raises the curtain" and reducing the difficulty of operation for users.

[0044] See Figure 4 , Figure 8 , Figure 9 and Figure 10A reduction gear transmission mechanism is connected between the fourth gear 23 and the first rotating shaft 13. Another reduction gear transmission mechanism with the same structure is also provided between the second rotating shaft 14 and the second turntable 21 to perform the reduction transmission function; details will not be elaborated here. The reduction gear transmission mechanism includes a first connecting post 25, a second connecting post 26, a third connecting post 27, and a first housing 28. The second connecting post 26 is connected between the first connecting post 25 and the third connecting post 27. One end of the first connecting post 25 is connected to the fourth gear 23, and the other end of the first connecting post 25 is provided with a first connecting block 2501. The end of the second connecting post 26 near the first connecting post 25 is provided with a second connecting block 2601. Two first mounting slots 34 are provided between the first connecting block 2501 and the second connecting block 2601. A first clamping spring 32 is sleeved on the outer side of the first connecting block 2501 and the second connecting block 2601. The first clamping spring 32 is provided with a first support leg 3201 and a second support leg 3202. 3201 is placed in one of the first mounting slots 34, and the second support leg 3202 is placed in the other first mounting slot 34; the third connecting column 27 is connected to the first rotating shaft 13, and a first planetary carrier 29 is provided on the third connecting column 27. Several first planetary gears 30 are provided on the first planetary carrier 29. The first housing 28 is fixedly connected to the upper beam track 1. A first sun gear 31 is provided on the second connecting column 26, and a first gear ring 2801 is provided inside the first housing 28. The first planetary gears 30 mesh with both the first sun gear 31 and the first gear ring 2801. A first clamping spring 32 is provided, so that the preload of the first clamping spring 32 tightly clamps the first connecting column 2501 and the second connecting column 2601, so that power is transmitted from the fourth gear 23 to the second connecting column 2601; the reduction transmission mechanism transmits power from the second connecting column 2601 through the fixed first gear ring 2801, and after reduction by the first planetary gears, outputs power from the first planetary carrier 29; see reference. Figure 11 , Figure 13 and Figure 14The first pull rope assembly 90 includes a second reduction transmission mechanism, which includes a fourth connecting post 35, a fifth connecting post 36, a sixth connecting post 37, and a second housing 38. The fifth connecting post 36 is connected between the fourth connecting post 35 and the sixth connecting post 37. One end of the fourth connecting post 35 is connected to the second turntable 21, and the other end of the fourth connecting post 35 is provided with a third connecting block 3501. The end of the fifth connecting post 36 near the fourth connecting post 35 is provided with the fourth connecting block 3601, and the third connecting block 3501 is connected to... Two second mounting slots 39 are provided between the fourth connecting blocks 3601. Second clamping springs 40 are provided on the outer sides of the third connecting block 3501 and the fourth connecting block 3601. The second clamping springs 40 are equipped with a third support leg 4001 and a fourth support leg 4002. The third support leg 4001 is placed in one of the mounting slots 39, and the fourth support leg 4002 is placed in the other mounting slot 39. The sixth connecting column 37 is connected to the second rotating shaft 14. A second planetary carrier 41 is provided on the sixth connecting column 37. The planetary carrier 41 is equipped with several second planetary gears 42. The second housing 38 is fixedly connected to the upper beam track 1. The fifth connecting column 36 is equipped with a second sun gear 43. The second gear ring 3801 is provided on the inner side of the second housing 38. The second planetary gears 42 mesh with both the second sun gear 43 and the second gear ring 3801. The first and second reduction transmission mechanisms achieve deceleration and increase the output torque, allowing the user to pull the pull rope with a small force. The mechanism generates a sufficiently large torque to lift the curtain, reducing the operating effort and making the lifting process more effortless and smooth, thus improving the user experience. In addition, when there is no external force pulling the first pull rope 9 and the second pull rope 8, the first and second reduction transmission mechanisms lock the second screw 7 and the first screw 6. In the planetary gear system, when the gear ring is fixed and the planetary carrier is used as the input, the system will self-lock, generating a large internal resistance, which will prevent the planetary carrier from rotating. This will allow the first screw 6 and the second screw 7 to be driven to rotate only by pulling the corresponding pull rope with external force.

[0045] See Figure 3 , Figure 5 , Figure 6 and Figure 12 A limiting sleeve 24 is detachably provided on the outer side of the first limiting nut 10. A bolt 33 connects the first limiting nut 10 and the limiting sleeve 24, securing them together for easy assembly. A second limiting protrusion 1002 is provided on the outer side of the first limiting nut 10. A second limiting groove 2401 is provided on the inner side of the limiting sleeve 24 along its axial direction. The second limiting protrusion 1002 is placed within the second limiting groove 2401 for limiting. An inner sidewall 101 is provided on the upper beam track 1, and an abutment block 2402 is provided on the side of the limiting sleeve 24 near the inner sidewall 101. (See reference...) Figure 3In this embodiment, the upper beam track 1 includes a mounting base 100, and the first screw 6 and the second screw 7 are rotatably mounted on the mounting base 100. The inner sidewall 101 is mounted on the mounting base 100. In use, the abutment block 2402 abuts against the inner sidewall 101 to restrict the circumferential rotation of the limiting sleeve 24 and the first limiting nut 10 relative to the upper beam track 1, thereby allowing the first limiting nut 10 to move in the axial direction, thus playing a limiting role. A limiting sleeve 24 that can be separated from the first limiting nut 10 is provided, so that the initial position of the first limiting nut 10 on the screw can be adjusted, which is convenient for adjusting the position of the first limiting nut 10 at the factory, and the curtain does not need to be unfolded during adjustment, making the operation convenient.

[0046] The double curtain linkage limiting structure of this utility model limits the first screw and the second screw by the first limiting nut and the second limiting nut respectively, so that the middle rail and the lower rail are limited at their respective lower limit positions, avoiding the problem of the curtain rope rewinding in reverse due to excessive operation during the curtain lowering process; at the same time, the first screw and the second screw can be linked to prevent the second curtain from being lowered too much and interfering with the first curtain, resulting in a better user experience.

[0047] In addition, this utility model also provides a curtain, including the above-mentioned double curtain linkage limiting structure. This curtain also has the beneficial effects of the above-mentioned double curtain linkage limiting structure, which will not be described in detail here.

[0048] In the description of this disclosure, it should be understood that the terms "upper", "lower", "bottom", "inner", "outer", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0049] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0051] In this disclosure, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first feature or in indirect contact with the first feature through an intermediate medium.

[0052] It should be noted that when a component is described as being "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is described as "connected to another component," it can be directly connected to the other component or there may be an intervening component. Furthermore, when a component is described as being "fixedly connected" to another component, the connection can be detachable or non-detachable, such as through socketing, snap-fitting, integral molding, welding, etc., which are achievable in conventional technologies and will not be elaborated upon here.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A double-curtain linkage limiting structure, characterized in that, The system includes an upper beam track (1), a middle track (2), a lower track (3), and a first pull rope assembly (90) disposed on the upper beam track (1). A first curtain (4) is disposed between the middle track (2) and the lower track (3). A second curtain (5) is disposed between the upper beam track (1) and the middle track (2). A first screw (6) and a second screw (7) are disposed on the upper beam track (1). A first limiting nut (10) is threaded onto the first screw (6). A first limiting block (601) is disposed at one end of the first screw (6). A second limiting nut (11) is threaded onto the second screw (7). A second limiting block (701) is disposed at one end of the second screw (7). A rotating sleeve (12) is provided on the outer side, and the second limiting nut (11) is slidably sleeved on the inner side of the rotating sleeve (12) along the axial direction of the rotating sleeve (12). A first gear (602) is provided on the first screw (6), and a second gear (1201) is provided on the rotating sleeve (12) to mesh with the first gear (602). When the second curtain (5) has been pulled up a certain distance and the first curtain (4) needs to be pulled up, the first screw (6) drives the rotating sleeve (12) to rotate through the meshing of the first gear (602) and the second gear (1201). The rotating sleeve (12) drives the second limiting nut (11) to rotate, so as to realize the pulling up of the first curtain (4).

2. The double-curtain linkage limiting structure according to claim 1, characterized in that, The second limiting nut (11) is provided with a first limiting protrusion (1101), and the rotating sleeve (12) is provided with a first limiting groove (1202) along its own axial direction. The first limiting protrusion (1101) is slidably placed in the first limiting groove (1202).

3. The double-curtain linkage limiting structure according to claim 1, characterized in that, The first limiting nut (10) has a first protruding tooth (1001) at one end, and the first limiting block (601) has a first slot (6011) corresponding to the first protruding tooth (1001); the second limiting nut (11) has a second protruding tooth (1102) at one end, and the second limiting block (701) has a second slot (7011) corresponding to the second protruding tooth (1102).

4. The double-curtain linkage limiting structure according to claim 1, characterized in that, The first curtain (4) is made of light-transmitting material, and the second curtain (5) is made of light-blocking material; or, the first curtain (4) is made of light-blocking material, and the second curtain (5) is made of light-transmitting material.

5. The double-curtain linkage limiting structure according to claim 1, characterized in that, It also includes a second pull cord assembly. The first pull cord assembly (90) includes a first pull cord (9), and the second pull cord assembly includes a second pull cord (8). The first pull cord (9) is provided with a first pull-up part (91) and a first pull-down part (92). The second pull cord (8) is provided with a second pull-up part (81) and a second pull-down part (82). The first curtain (4) and the second curtain (5) are located on the same vertical plane. In use, by pulling the first pull-up part (91), the second screw (7) is driven to rotate in the opposite direction, so as to drive the middle rail (2) to move upward. By pulling the first pull-down part (92), the second screw (7) is driven to rotate in the forward direction, so as to drive the middle rail (2) to move downward. By pulling the second pull-up part (81), the first screw (6) is driven to rotate in the opposite direction, so as to drive the lower rail (3) to move upward. By pulling the second pull-down part (82), the first screw (6) is driven to rotate in the forward direction, so as to drive the lower rail (3) to move downward.

6. The double-curtain linkage limiting structure according to claim 5, characterized in that, The upper beam track (1) is provided with a first rotating shaft (13) and a second rotating shaft (14). The first rotating shaft (13) is connected to the first screw (6) and rotates synchronously. The second rotating shaft (14) is connected to the second screw (7) and rotates synchronously. The first rotating shaft (13) is provided with a first rope drum (15). The first rope drum (15) is connected to the first curtain (4) with a first curtain rope (16). The second rotating shaft (14) is provided with a second rope drum (17). The second rope drum (17) is connected to the second curtain (5) with a second curtain rope (18).

7. The double-curtain linkage limiting structure according to claim 6, characterized in that, A wire groove (19) is provided between the first rope drum (15) and the second rope drum (17). The first curtain rope (16) and the second curtain rope (18) both pass through the wire groove (19). The upper beam track (1) is provided with a first turntable (20) for installing the second pull rope (8) and a second turntable (21) for installing the first pull rope (9). A third gear (22) that rotates synchronously with the first turntable (20) is provided on one side of the first turntable (20). One end of the first rotating shaft (13) is connected to a fourth gear (23) that meshes with the third gear (22). The second pull rope (8) and the first pull rope (9) are respectively provided on both sides of the upper beam track (1). The first pull rope (9) is the first pull bead rope, and the second pull rope (8) is the second pull bead rope.

8. The double-curtain linkage limiting structure according to claim 7, characterized in that, The second pull rope assembly includes a first reduction transmission mechanism disposed between the fourth gear (23) and the first rotating shaft (13). The first reduction transmission mechanism includes a first connecting post (25), a second connecting post (26), a third connecting post (27), and a first housing (28). The second connecting post (26) is connected between the first connecting post (25) and the third connecting post (27). One end of the first connecting post (25) is connected to the fourth gear (23), and the other end of the first connecting post (25) is provided with a first connecting block (2501). The end of the second connecting post (26) near the first connecting post (25) is provided with a second connecting block (2601). Two first mounting slots (34) are provided between the first connecting block (2501) and the second connecting block (2601). The outer surfaces of the first connecting block (2501) and the second connecting block (2601) are... A first clamping spring (32) is provided on the side sleeve. The first clamping spring (32) is provided with a first support foot (3201) and a second support foot (3202). The first support foot (3201) is placed in one of the first mounting slots (34), and the second support foot (3202) is placed in the other first mounting slot (34). The third connecting column (27) is connected to the first rotating shaft (13). A first planetary carrier (29) is provided on the third connecting column (27). A plurality of first planetary gears (30) are provided on the first planetary carrier (29). The first housing (28) is fixedly connected to the upper beam track (1). A first sun gear (31) is provided on the second connecting column (26). A first gear ring (2801) is provided on the inner side of the first housing (28). The first planetary gears (30) mesh with the first sun gear (31) and the first gear ring (2801) at the same time.The first pull rope assembly (90) includes a second reduction transmission mechanism, which includes a fourth connecting post (35), a fifth connecting post (36), a sixth connecting post (37), and a second housing (38). The fifth connecting post (36) is connected between the fourth connecting post (35) and the sixth connecting post (37). One end of the fourth connecting post (35) is connected to the second turntable (21), and the other end of the fourth connecting post (35) is provided with a third connecting block (3501). The end of the fifth connecting post (36) near the fourth connecting post (35) is provided with a fourth connecting block (3601). Two second mounting slots (39) are provided between the third connecting block (3501) and the fourth connecting block (3601). A second clamping spring (4) is provided on the outside of the third connecting block (3501) and the fourth connecting block (3601). 0), the second clamping spring (40) is provided with a third support leg (4001) and a fourth support leg (4002). The third support leg (4001) is placed in one of the second mounting slots (39), and the fourth support leg (4002) is placed in the other second mounting slot (39). The sixth connecting column (37) is connected to the second rotating shaft (14). The sixth connecting column (37) is provided with a second planetary carrier (41). The second planetary carrier (41) is provided with a plurality of second planetary gears (42). The second housing (38) is fixedly connected to the upper beam track (1). The fifth connecting column (36) is provided with a second sun gear (43). The second housing (38) is provided with a second gear ring (3801) on the inner side of the second housing (38). The second planetary gears (42) mesh with the second sun gear (43) and the second gear ring (3801) at the same time.

9. The double-curtain linkage limiting structure according to claim 1, characterized in that, A limiting sleeve (24) is detachably provided on the outside of the first limiting nut (10). A second limiting protrusion (1002) is provided on the outside of the first limiting nut (10). A second limiting groove (2401) is provided on the inner side of the limiting sleeve (24) along its own axial direction. The second limiting protrusion (1002) is placed in the second limiting groove (2401) for limiting. An inner sidewall (101) is provided on the upper beam track (1). An abutment block (2402) is provided on the side of the limiting sleeve (24) close to the inner sidewall (101). In use, the abutment block (2402) abuts against the inner sidewall (101) to restrict the circumferential rotation of the limiting sleeve (24) and the first limiting nut (10) relative to the upper beam track (1).

10. A curtain, characterized in that, Includes the double-curtain linkage limiting structure as described in any one of claims 1-9.

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