Curtain limiter

Abstract

The embodiment of the invention provides a curtain limiter which comprises a base, the base comprises a bottom plate and end plates, the end plates are bent in the same direction from the two opposite ends of the bottom plate and extend in parallel, through holes for a transmission shaft of a curtain to penetrate through are formed in the end plates, and a guide structure located between the two end plates is further arranged on the base; the external thread section is arranged on the outer side wall of the transmission shaft and is arranged between the two end plates; the sliding module is arranged between the two end plates and comprises a sliding frame which can only slide back and forth in the axial direction of the transmission shaft under the guide of the guide structure, an adjusting sleeve which is pivoted on the sliding frame and a locking piece which is arranged on the sliding frame and is used for locking the adjusting sleeve on the sliding frame; the hole wall of an inner hole of the adjusting sleeve is provided with an internal thread, and the adjusting sleeve is sleeved on the transmission shaft and is correspondingly screwed with the external thread section through the internal thread. The curtain limiting stopper is simple in structure, cost can be reduced, and assembling and adjusting operation are convenient.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of curtain fittings, in particular to a curtain limiter. BACKGROUND

[0002] The existing curtain generally comprises an upper beam, a curtain body arranged below the upper beam, a winding drum and a power mechanism assembled on the upper beam, and a load rope with one end wound on the winding drum and the other end extending downward and connected to the curtain body. The power mechanism is connected to the winding drum through a transmission shaft, and the power mechanism can drive the winding drum to rotate correspondingly to wind the load rope to lift the curtain body. When a user pulls down the curtain body, the load rope descends with the curtain body and drives the winding drum to rotate reversely to release the load rope. In order to effectively limit the upper and lower limit positions of the curtain body lifting to be compatible with various height specifications of the curtain, the existing curtain generally further comprises a curtain limiter arranged on the upper beam and connected to the transmission shaft.

[0003] The existing curtain limiter comprises a base fixed on the upper beam, a nut fixed on one end of the base, a long threaded sleeve sleeved on the transmission shaft and screwed with the nut and having a radial protrusion at one end to form a stop protrusion, a movable stop block arranged between the stop protrusion and the nut for limiting the stop protrusion, and a locking assembly. The long threaded sleeve is configured to be fixed in the circumferential direction relative to the transmission shaft and axially movable relative to the transmission shaft. The movable stop block can be adjusted in position along the axial direction of the long threaded sleeve and locked by the locking assembly after adjustment. Since the long threaded sleeve is screwed with the nut and the nut is fixed, the long threaded sleeve will axially displace relative to the nut when the long threaded sleeve rotates with the transmission shaft. When the long threaded sleeve abuts against the movable stop block, the transmission shaft and the winding drum will be prevented from continuing to rotate, thereby stopping the release of the load rope. At this time, it corresponds to the lower limit position of the curtain body.

[0004] However, the inventor found in the specific implementation that the long threaded sleeve of the above-mentioned curtain limiter will axially displace when rotating with the transmission shaft, and will extend to the side of the nut away from the movable stop block, so that a larger space needs to be reserved on the corresponding side of the nut, which is not conducive to the layout design of the components on the upper beam. SUMMARY

[0005] The technical problem to be solved by the embodiment of the present application is to provide a curtain limiter which is simple in structure and convenient to assemble and adjust.

[0006] In order to solve the above technical problem, the embodiment of the present application first provides the following technical solution: a curtain limiter comprising: The base comprises a bottom plate fixed to the upper beam of the curtain, and end plates bent from the opposite ends of the bottom plate and extending in parallel, the end plates being provided with through holes for the transmission shaft of the curtain to pass through, and the base is further provided with a guide structure between the two end plates; An externally threaded segment arranged on the outer side wall of the transmission shaft and between the two end plates of the base; and A sliding module arranged between the two end plates, the sliding module comprising a sliding frame capable of sliding back and forth in the axial direction of the transmission shaft under the guidance of the guide structure, an adjusting sleeve pivotally arranged on the sliding frame, and a locking member arranged on the sliding frame for locking the adjusting sleeve to the sliding frame, the adjusting sleeve being provided with an internal thread on the inner hole wall, and the adjusting sleeve being sleeved on the transmission shaft and being correspondingly screwed with the externally threaded segment.

[0007] Further, the outer side wall of the adjusting sleeve is provided with a plurality of limiting tooth slots uniformly distributed in the circumferential direction, and the locking member is provided with a tooth for being correspondingly clamped into the limiting tooth slot to prevent the adjusting sleeve from rotating.

[0008] Further, the adjusting sleeve is composed of a gear having the inner hole formed at the shaft center, the tooth slots on the outer circumferential surface of the gear forming the limiting tooth slots, and the opposite ends of the gear in the axial direction respectively protruding to form stub shafts, the two stub shafts being respectively inserted into the corresponding shaft holes formed on the sliding frame.

[0009] Further, one end of the locking member is pivotally connected to the sliding frame by means of a pivot, and the other end is provided with an elastic hook for being correspondingly clamped with a clamping block prearranged on the sliding frame to lock the locking member.

[0010] Further, the guide structure comprises at least one of the following structures: Guide side plates arranged on the opposite sides of the bottom plate and extending in parallel to the axial direction of the transmission shaft, the guide side plates being integrated with the bottom plate and / or the end plate, and the opposite side surfaces of the sliding frame respectively abutting the two guide side plates; and A slide rail arranged in the middle of the bottom plate and extending in parallel to the axial direction of the transmission shaft, and the adjacent side of the sliding frame being provided with a sliding part for slidingly connecting with the slide rail.

[0011] Further, the outer thread section comprises an equal-pitch outer thread section and an increased-pitch outer thread section connected to one end of the equal-pitch outer thread section, the pitch of the increased-pitch outer thread section is greater than the pitch of the equal-pitch outer thread section and the circumferential length of the increased-pitch outer thread section is not greater than one fourth of a circle, the inner thread is a thread provided at the inner hole close to the aperture of the increased-pitch thread section and has a notch with a circumferential length less than a circle, the inner hole wall is further provided with a receiving groove in communication with the notch for corresponding receiving the increased-pitch outer thread section, the increased-pitch outer thread section is slid into the receiving groove through the notch, and the groove side wall adjacent to one side of the notch forms a guide slope for guiding the sliding of the increased-pitch outer thread section.

[0012] Further, the outer thread section is an outer thread pipe corresponding to be sleeved on the transmission shaft, the inner wall of the outer thread pipe and the outer wall of the transmission shaft are relatively fixed in the circumferential direction by the convex edges and the concave grooves respectively corresponding arranged and extending in the axial direction, and the outer thread pipe is further relatively fixed in the axial direction with the base.

[0013] Further, the through hole penetrates to one side edge of the end plate to form an opening, and the transmission shaft is correspondingly clamped into the through hole through the opening.

[0014] Further, one end of the outer thread pipe further radially protrudes to form a stop ring for limiting the abutment of the sliding frame of the sliding module, and the stop ring is further provided with a corresponding outward protruding ratchet wheel towards one side surface of the sliding frame, and the adjacent outer side wall of the sliding frame is correspondingly provided with a stop block for circumferentially abutting and limiting with the ratchet teeth of the ratchet wheel.

[0015] Further, the outer side wall of one end of the outer thread pipe further forms an annular clamping groove, the outer thread pipe is clamped into the through hole on the end plate through the opening with the annular clamping groove, the end plate around the through hole is correspondingly clamped into the annular clamping groove, and the opposite two side groove walls of the annular clamping groove hold the end plate so that the outer thread pipe and the base are relatively fixed in the axial direction; the other end of the outer thread pipe is further sleeved with a support block, the support block is correspondingly clamped into the through hole through the opening, and one end of the support block away from the outer thread pipe is hooked and fixed in the clamping hole correspondingly provided on the end plate.

[0016] The application has at least the following beneficial effects: the outer threaded section is arranged on the outer side wall of the transmission shaft, and is arranged between the two end plates of the base, the adjusting sleeve is sleeved on the outer threaded section, the inner thread in the inner hole of the adjusting sleeve is screwed with the outer threaded section, the adjusting sleeve is locked on the sliding frame by the locking member, the sliding frame is axially slidable by cooperating with the guide structure on the base, so that the sliding frame is axially moved when the transmission shaft rotates, and the sliding frame is stopped and positioned when abutting against the end plate of the corresponding end of the base, the outer threaded section does not axially move in the whole movement process, and the layout design of the components on the upper beam is facilitated without considering the external reserved avoiding space, the adjusting sleeve can be rotated to pre-set the initial position of the adjusting sleeve in the axial direction after the locking member is unlocked, and the locking member is locked, so that the limiting stroke of the curtain positioner is adjusted to adapt to different specifications of the curtain, the whole curtain positioner can be modularly manufactured and assembled, the structure is simple, and the cost is reduced and the assembly is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure schematic view of the curtain positioner assembled to the upper beam in an optional embodiment of the application.

[0018] Figure 2 The structure schematic view of the curtain positioner in a disassembled state in an optional embodiment of the application.

[0019] Figure 3 The internal structure schematic view of the adjusting sleeve in an optional embodiment of the curtain positioner.

[0020] Figure 4 The structure schematic view of the outer threaded pipe in an optional embodiment of the curtain positioner.

[0021] Figure 5 The structure schematic view of the sliding frame in an optional embodiment of the curtain positioner.

[0022] Figure 6 The sectional view of an optional embodiment of the curtain positioner along a sectional plane perpendicular to the middle axis of the transmission shaft and the plate surface of the bottom plate.

[0023] Figure 7 The sectional view of an optional embodiment of the curtain positioner along a sectional plane parallel to the middle axis of the transmission shaft and the plate surface of the bottom plate.

[0024] Figure 8 The sectional view of another optional embodiment of the curtain positioner along a sectional plane perpendicular to the middle axis of the transmission shaft.

[0025] Figure 9 Figure 6 is a sectional view of another alternative embodiment of the curtain positioner of the present application along a section plane perpendicular to the central axis of the transmission shaft. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with the drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are merely intended to explain the present application and are not intended to limit the present application, and the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0027] As shown in Figures 1-9 Figure 1, an alternative embodiment of the present application provides a curtain positioner, which comprises: a base 1, the base 1 comprising a bottom plate 10 fixed to the upper beam 9 of the curtain and end plates 12 bent from the opposite ends of the bottom plate 10 in the same direction and extending in parallel, the end plates 12 being provided with through holes 120 for the transmission shaft 8 of the curtain to pass through, and the base 1 being further provided with a guide structure 14 between the two end plates 12; an outer threaded section 3 provided on the outer side wall of the transmission shaft 8 and between the two end plates 12 of the base 1; and a sliding module 5 between the two end plates 12, the sliding module 5 comprising a sliding frame 50 capable of sliding back and forth in the axial direction of the transmission shaft 8 under the guidance of the guide structure 14, an adjusting sleeve 52 pivotally provided on the sliding frame 50, and a locking member 54 provided on the sliding frame 50 for locking the adjusting sleeve 52 to the sliding frame 50, the inner hole 520 of the adjusting sleeve 52 being provided with internal threads 522, the adjusting sleeve 52 being sleeved on the transmission shaft 8 and being correspondingly screwed with the outer threaded section 3 through the internal threads 522.

[0028] The present application sets the outer thread section 3 on the outer wall of the transmission shaft 8, and sets the outer thread section 3 between the two end plates 12 of the base 1, sets the adjusting sleeve 52 on the outer thread section 3, the inner thread 522 in the inner hole 520 of the adjusting sleeve 52 is screwed with the outer thread section 3, and the adjusting sleeve 52 is locked on the sliding frame 50 through the locking member 54, the sliding frame 50 is matched with the guide structure 14 on the base 1, and can only slide axially, so that the adjusting sleeve 52 is driven by the outer thread section 3 when the transmission shaft 8 rotates, and the sliding frame 50 is axially moved, and the sliding frame 50 is abutted to the end plate 12 of the corresponding end of the base 1 to realize the stop limiting, the outer thread section 3 does not move axially in the whole movement process, and external reserved avoidance space is not considered, the layout design of many components on the upper beam is facilitated, and in addition, the adjusting sleeve 52 can be rotated to pre-set the initial position of the adjusting sleeve 52 in the axial direction by only unlocking the locking member 54, and then the locking member 54 is locked, so that the limiting stroke of the curtain positioner is adjusted to adapt to curtains of different specifications, the whole curtain positioner can also realize modular manufacturing and assembly, the structure is simple, and the cost is reduced and the assembly is facilitated.

[0029] In an optional embodiment of the present application, as shown in Figure 2 , Figure 8 and Figure 9 , the outer wall of the adjusting sleeve 52 is provided with a plurality of limiting clamping grooves 524 uniformly distributed in the circumferential direction, and the locking member 54 is provided with a clamping tooth 540 which is clamped into the limiting clamping groove 524 to prevent the rotation of the adjusting sleeve 52. In this embodiment, the limiting clamping groove 524 and the clamping tooth 540 are matched to lock the adjusting sleeve 52, which has a simple structure and good locking effect.

[0030] In an optional embodiment of the present application, as shown in Figure 2 , Figures 6-9 , the adjusting sleeve 52 is composed of a gear with the inner hole 520 formed at the shaft center, the tooth groove on the outer circumferential surface of the gear constitutes the limiting clamping groove 524, and the opposite two ends of the gear in the axial direction are respectively protruded to form a short shaft 526, and the two short shafts 526 are respectively inserted into the shaft hole 500 correspondingly formed on the sliding frame 50. In this embodiment, the gear with the inner hole 520 formed at the shaft center is used as the adjusting sleeve 52, so that the tooth groove on the outer circumferential surface of the gear can be well used as the limiting clamping groove 524, the clamping tooth 540 is clamped into any one tooth groove to lock the adjusting sleeve 52, and the adjusting precision is high. The short shaft 526 formed at the two ends of the gear is inserted into the shaft hole 500 on the sliding frame 50 to realize the pivoting, and the opposite two end walls 501 of the sliding frame 50 which are provided with the shaft hole 500 can stop the end surface of the gear to limit the gear in the axial direction, so that the axial movement of the gear is avoided.

[0031] In an alternative embodiment of the present application, as shown in Figure 2 , Figure 8 and Figure 9 , one end of the locking member 54 is pivotally connected to the sliding frame 50 by means of a pivot 542, and the other end is provided with an elastic clamping hook 544 for clamping and locking the locking member 54 corresponding to the clamping block 502 provided on the sliding frame 50. In this embodiment, the locking member 54 is locked by clamping and hooking the elastic clamping hook 544 with the clamping block 502 on the sliding frame 50, which is convenient for locking and unlocking, and the end of the locking member 54 is also pivotally connected to the sliding frame 50, which will not easily fall off after unlocking.

[0032] In an alternative embodiment of the present application, as shown in Figure 2 , Figure 8 and Figure 9 , the guide structure 14 comprises at least one of the following structures: guide side plates 140 provided on opposite sides of the bottom plate 10 and extending axially parallel to the transmission shaft 8, the guide side plates 140 being integrated with the bottom plate 10 and / or the end plate 12, and the opposite sides of the sliding frame 50 being respectively attached to two of the guide side plates 140; and a slide rail 142 provided in the middle of the bottom plate 10 and extending axially parallel to the transmission shaft 8, and the adjacent sides of the sliding frame 50 being provided with slide portions 503 for slidingly connecting with the slide rail 142.

[0033] This embodiment provides two kinds of guide structures, which can be flexibly selected during specific implementation. The guide side plates 140 are used as the guide structure, and the guide side plates 140 can also form a semi-enclosed box body with the bottom plate 10 and the end plate 12, which is only open on the side opposite to the bottom plate 10, and the outer thread segment 3 and the sliding module 5 can be accommodated in the box body, the entire window curtain position limiter has stronger integrity and better modularization characteristics, and external objects can be prevented from easily touching the outer thread segment 3 and the sliding module 5, thereby improving the structural safety and the positioning accuracy. The slide rail 142 and the slide portion 503 are used to realize the guidance, and the structure is relatively simple and the guidance effect is good. In specific implementation, the inner side of the guide side plate 140 can also form a stepped surface 141, and the corresponding side of the sliding frame 50 can also form a stepped portion 504 adapted thereto, so as to further improve the guidance effect of the guide side plate 140 on the sliding frame 50. The slide rail 142 can be a slide groove track (as shown in Figure 9 ), a convex rail or a guide column, and correspondingly, the slide portion 503 can be a sliding block provided in the slide groove track or slidingly connected to the convex rail or the guide column.

[0034] In an alternative embodiment of the present application, as shown in Figure 2 , Figure 3 and Figure 4 , the outer thread segment 3 comprises an equal-pitch outer thread segment 30 and an increased-pitch outer thread segment 32 connected to one end of the equal-pitch outer thread segment 30, the pitch of the increased-pitch outer thread segment 32 is greater than that of the equal-pitch outer thread segment 30 and the circumferential length of the increased-pitch outer thread segment 32 is not greater than one fourth of a circle, the inner thread 522 is a thread provided at one end of the inner hole 520 close to the increased-pitch outer thread segment 32 and has a notch 527 with a circumferential length less than one circle, the hole wall of the inner hole 520 is further provided with a receiving groove 528 in communication with the notch 527 for corresponding receiving the increased-pitch outer thread segment 32, the increased-pitch outer thread segment 32 is slid into the receiving groove 528 through the notch 527, and the side groove wall of the receiving groove 528 adjacent to one side of the notch 524 forms a guide slope 529 for guiding the sliding of the increased-pitch outer thread segment 32. In this embodiment, the outer thread segment 3 is designed as two segments with different pitches, so that when the inner thread 522 of the adjusting sleeve 52 of the sliding module 5 cooperates with the equal-pitch outer thread segment 30, the axial sliding of the sliding module 5 is relatively balanced, and when the inner thread 522 of the adjusting sleeve 52 starts to cooperate with the increased-pitch outer thread segment 32, the axial movement is accelerated, thereby quickly reaching the stop limiting purpose.

[0035] In an alternative embodiment of the present application, as shown in Figure 2 , Figure 4 , Figures 6-9 , the outer thread segment 3 is an outer thread pipe corresponding to being sleeved on the transmission shaft 8, the inner wall of the outer thread pipe and the outer wall of the transmission shaft 8 are relatively fixed in the circumferential direction by being respectively correspondingly provided with and extending in the axial direction the convex rib 31 and the concave groove 81 and being interlocked with each other, and the outer thread pipe is further relatively fixed in the axial direction with the base 1. In this embodiment, the outer thread segment 3 is formed by sleeving the outer thread pipe on the transmission shaft 8, which facilitates the selection and assembly of parts and is conducive to reducing costs.

[0036] In an alternative embodiment of the present application, as shown in Figure 2 and Figure 6 , the through hole 120 penetrates to one side edge of the end plate 12 to form an opening 122, and the transmission shaft 8 is correspondingly clamped into the through hole 120 through the opening 122. In this embodiment, the through hole 120 is designed to penetrate to one side edge to form an opening 122, so that the transmission shaft 8 can be directly clamped into the through hole 120 through the opening 122 during assembly, thereby improving the assembly efficiency.

[0037] In an alternative embodiment of the present application, as shown in Figure 2 , Figures 4-7As shown, one end of the externally threaded tube also radially protrudes to form a stop ring 35 for correspondingly abutting against the sliding frame 50 of the sliding module 5 and limiting its movement. The side surface of the stop ring 35 facing the sliding frame 50 is also provided with a correspondingly protruding ratchet 350. The adjacent outer side wall of the sliding frame 50 is correspondingly provided with a stop block 56 that abuts against the ratchet teeth of the ratchet 350 in the circumferential direction for limiting its movement. In this embodiment, by forming a stop ring 35 at one end of the externally threaded tube, the stop ring 35 abuts against the sliding frame 50 to achieve stopping. Furthermore, the ratchet 350 formed on the side of the stop ring 35 engages with the stop block 56 on the sliding frame 50 to achieve circumferential limiting, effectively preventing further rotation of the externally threaded tube and the drive shaft 8, resulting in a better limiting effect.

[0038] In an optional embodiment of the present invention, such as Figure 2 , Figure 6 and Figure 7 As shown, an annular groove 58 is formed on the outer side wall of one end of the externally threaded tube. The externally threaded tube is inserted into the through hole 120 on the end plate 12 through the opening 122 via the annular groove 58. The end plate 12 around the through hole 120 is correspondingly inserted into the annular groove 58. The opposite side walls of the annular groove 58 clamp the end plate 12, thereby fixing the externally threaded tube and the base 1 axially. A support block 59 is also sleeved on the other end of the externally threaded tube. The support block 59 is correspondingly inserted into the through hole 120 via the opening 122. The end of the support block 59 away from the externally threaded tube is hooked and fixed in the corresponding locking hole 123 on the end plate 12. In this embodiment, an annular groove 58 is formed at one end of the externally threaded tube. This groove 58 is aligned with and interlocks with the through hole 120 on the end plate 12. The opposite side walls of the annular groove 58 hold the end plate 12, thus achieving axial relative fixation between the externally threaded tube and the base 1. A support block 59 is fitted onto the other end of the externally threaded tube. This support block 59 is inserted into the through hole 120 and hooked and fixed to the end plate 12, effectively and stably supporting the externally threaded tube. This prevents the externally threaded tube and the drive shaft 8 from bending, deforming, or radially running, resulting in smoother power transmission.

[0039] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many variations under the guidance of the present invention without departing from the spirit of the invention and the scope of protection of the claims. These variations are all within the scope of protection of the present invention.

Claims

1. A curtain limiter, characterized in that, include: The base includes a bottom plate fixed to the upper beam of the curtain and end plates that bend in the same direction and extend in parallel from opposite ends of the bottom plate. The end plates are provided with through holes for the drive shaft of the curtain to pass through. The base is also provided with a guide structure located between the two end plates. An external threaded section is provided on the outer wall of the drive shaft and positioned between the two end plates of the base; and A sliding module is disposed between the two end plates. The sliding module includes a sliding frame that can only slide back and forth axially on the drive shaft under the guidance of the guide structure, an adjusting sleeve pivotally mounted on the sliding frame, and a locking member disposed on the sliding frame for locking the adjusting sleeve onto the sliding frame. The inner wall of the adjusting sleeve is provided with an internal thread. The adjusting sleeve is sleeved on the drive shaft and the internal thread is screwed into the corresponding external thread section.

2. The curtain limiter as described in claim 1, characterized in that, The outer wall of the adjusting sleeve is provided with a number of limiting grooves evenly distributed in the circumferential direction, and the locking member is provided with corresponding locking teeth that are engaged in the limiting grooves to prevent the adjusting sleeve from rotating.

3. The curtain limiter as described in claim 2, characterized in that, The adjusting sleeve is composed of a gear with an inner hole formed at the center of the shaft. The tooth grooves on the outer circumference of the gear form the limiting groove. The two opposite ends of the gear in the axial direction respectively protrude to form short shafts, and the two short shafts are respectively inserted into the corresponding shaft holes formed on the sliding frame.

4. The curtain limiter as described in claim 1, characterized in that, One end of the locking member is pivotally connected to the sliding frame by means of a pivot, while the opposite end is provided with an elastic hook for engaging with a pre-set locking block on the sliding frame to lock the locking member.

5. The curtain limiter as described in claim 1, characterized in that, The guiding structure includes at least one of the following structures: Guide side plates are disposed on opposite sides of the base plate and extend parallel to the axial direction of the drive shaft. The guide side plates are integrally connected to the base plate and / or the end plate. The opposite sides of the sliding frame are respectively abutted against the two guide side plates. A slide rail is provided in the middle of the base plate and extends axially parallel to the drive shaft. The adjacent side of the sliding frame is provided with a sliding part that slides and engages with the slide rail.

6. The curtain limiter as described in claim 1, characterized in that, The external thread segment includes a constant pitch external thread segment and an increasing pitch external thread segment connected to one end of the constant pitch external thread segment. The pitch of the increasing pitch external thread segment is greater than the pitch of the constant pitch external thread segment, and its circumferential length is no more than one-quarter turn. The internal thread is a thread with a notch located at the end of the inner hole near the increasing pitch external thread segment and with a circumferential length of less than one turn. The inner hole wall is also provided with a receiving groove connected to the notch for correspondingly receiving the increasing pitch external thread segment. The increasing pitch external thread segment slides into the receiving groove through the notch. The side wall of the receiving groove adjacent to the notch forms a guide slope to guide the sliding of the increasing pitch external thread segment.

7. The curtain limiter as described in claim 6, characterized in that, The external threaded section is an external threaded tube correspondingly sleeved on the drive shaft. The inner wall of the external threaded tube and the outer wall of the drive shaft are mutually engaged and fixed in the circumferential direction by correspondingly provided and axially extended protrusions and grooves. The external threaded tube is also fixed in the axial direction to the base.

8. The curtain limiter as described in claim 7, characterized in that, The through hole extends to one side edge of the end plate to form an opening, and the drive shaft is inserted into the through hole through the opening.

9. The curtain limiter as described in claim 8, characterized in that, One end of the externally threaded tube also protrudes radially to form a stop ring for correspondingly abutting against the sliding frame of the sliding module and limiting its position. The side surface of the stop ring facing the sliding frame is also provided with a correspondingly protruding ratchet. The adjacent outer side wall of the sliding frame is provided with a stop block that corresponds to the ratchet teeth of the ratchet and abuts against each other in the circumferential direction to limit its position.

10. The curtain limiter as described in claim 8, characterized in that, The outer side wall of one end of the externally threaded tube also forms an annular groove. The externally threaded tube is inserted into the through hole on the end plate through the annular groove and the opening. The end plate around the through hole is correspondingly inserted into the annular groove. The opposite side walls of the annular groove hold the end plate so that the externally threaded tube and the base are axially fixed. The other end of the externally threaded tube is also fitted with a support block. The support block is inserted into the through hole through the opening. The end of the support block away from the externally threaded tube is hooked and fixed in the corresponding locking hole on the end plate.

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