TWI892845B - Curtain limit linkage device - Google Patents

Abstract

A curtain limit linkage device includes a linkage and a clutch. The linkage has a base, a top cover, a first screw and a second screw. The base and the top cover are assembled relative to each other and define a hollow cylindrical braking channel therebetween. The first screw and the second screw are respectively screwed on the two ends of the braking channel. The linkage is respectively driven by the first and second screws. The screw controls the raising and lowering of the curtain's upper and lower beams. Not only does it synchronize the upper beam with the lower beam as it moves upward, but it also works in conjunction with the clutch to provide a geared linkage and a trip-out mechanism. This prevents over-operation of the linkage, further preventing the first and second rope pullers from rotating synchronously. This effectively reduces rope entanglement and knotting, significantly enhancing the structural durability and practicality.

Description

Curtain limit linkage device

The present invention relates to a curtain brake device, and more particularly to a curtain limit linkage device with a clutch.

Common two-stage curtains on the market today typically feature independently controlled first and second pull cords, each controlling a first and second reel to wind up and release the cords, raising or lowering the upper or lower beam, and further extending or closing the curtain between the upper and lower beams. When the user wishes to prevent outsiders from viewing the interior while still allowing light to enter the upper window, they can independently operate the upper and lower beams to adjust the area of the window covered by the curtain, meeting their needs.

However, in the process of actually manipulating the lower beam to increase the light-transmitting area, when the lower beam has completely retracted the curtain cloth (i.e., the distance between the lower beam and the upper beam reaches the minimum), the second pull rope is then pulled to cause the lower beam to continue to move upward, thereby further pushing the upper beam upward. As a result, the distance between the upper beam and the upper rail is reduced, causing the curtain to be completely retracted (i.e., the distance between the lower beam and the upper rail is minimized). The rope located between the upper beam and the upper rail, which drives the upper beam, is squeezed. Because the first reel is not driven to reel in the rope, the squeezed rope section cannot be reeled in and becomes slack. This not only ruins the overall aesthetics of the curtain, but may also cause the rope to become exposed, tangled, and knotted, making it impossible to untangle it, thus damaging the curtain. It also raises safety concerns arising from the possibility of foreign objects becoming entangled.

In light of this, the inventors, drawing upon their many years of experience in the manufacturing, development, and design of related products, have, after careful design and careful evaluation, ultimately arrived at this invention, which is truly practical and practicable, with the aforementioned objectives in mind.

The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and provide a curtain limit linkage device with a clutch, comprising a linkage and a clutch, wherein: the linkage has a base, a top cover, a first screw and a second screw, the base and the top cover are assembled relative to each other and define a hollow cylindrical braking channel therebetween, the base and the top cover are provided with communicating screws at both ends of the braking channel A first screw hole and a second screw hole are cocentric, the apertures of the first and second screw holes are smaller than the inner diameter of the braking channel, the first screw is screwed into the first screw hole, and one end of the first screw has a first baffle and is accommodated in the braking channel, the second screw is screwed into the second screw hole, and one end of the second screw has a second baffle and is accommodated in the braking channel, and the outer surfaces of the first baffle and the second baffle facing each other are provided with A first stage and a second stage that fit together; the clutch has a housing, a clutch block, a compression spring and a driven block. The housing has a receiving space and a non-circular through hole is provided at the center of one end to communicate with the receiving space, while the other end forms an opening for the clutch block and the compression spring to be assembled into the receiving space. The outer periphery of the housing is axially provided with a plurality of buckle columns. One end of the clutch block is against the compression spring. The clutch block further comprises a non-circular hole extending through the center of the clutch block. A central shaft protrudes from one end of the driven block, while the other end is provided with a plurality of teeth facing the clutch block. The teeth engage the ratchets in a unidirectional manner. Finally, the driven block is secured to the opening of the housing via the snap post. The clutch is connected to either the first screw or the second screw to form an actuator.

Preferably, the base is concave from top to bottom with a semi-cylindrical lower arc-shaped long groove, and then two fitting recesses are provided along the two long sides of the lower arc-shaped long groove on the upper surface of the base, and the two short sides of the base are respectively concave with a first lower thread arc segment in the shape of a semi-circular hole and a second lower thread arc segment connected to the lower arc-shaped long groove. The first and second lower thread arc segments are concentric with the lower arc-shaped long groove and are proportionally smaller, thereby forming two arc-shaped baffles at both ends of the lower arc-shaped long groove, and the two arc-shaped baffles are respectively convex with a first locking step and a second locking step; the top cover is concave from bottom to top with a semi-cylindrical upper arc-shaped long groove The top cover has two engaging protrusions formed on its lower surface along the two long sides of the upper arc-shaped slot. A first upper thread arc segment and a second upper thread arc segment are recessed on the two end edges of the top cover, each in the shape of a semicircular hole, communicating with the upper arc-shaped slot. The first and second upper thread arc segments are concentric with the upper arc-shaped slot and are proportionally smaller, thereby forming two arc-shaped retaining walls at both ends of the upper arc-shaped slot. The top cover is assembled by engaging the two engaging protrusions with the two engaging recesses of the base. Furthermore, the braking slot and the first and second screw holes communicating with the two ends of the braking slot are defined between the base and the top cover.

Preferably, the two mating recessed surfaces of the base are provided with a plurality of screw holes at equal intervals, and the top cover is further provided with a plurality of through-holes at equal intervals through the two mating protruding portions from top to bottom, and a plurality of screws are screwed through the through-holes and into the screw holes to tighten the top cover.

Preferably, at least two grooves are formed between the two long sides of the base, extending through the surface of the lower arc-shaped elongated groove. At least one reinforcing rib is further provided between the two long sides of the base bottom. At least two grooves are formed between the two long sides of the top cover, extending through the surface of the upper arc-shaped elongated groove. At least one reinforcing rib is further provided between the two long sides of the top cover.

Preferably, the first baffle of the first screw has a first embedded portion on its inner surface, and the second screw has a second embedded portion on its inner surface. The first and second embedded portions respectively correspond to the first and second engaging steps of the buckle to form a positioning.

Preferably, the internal thread sections of the first and second screw holes form counterclockwise rotating reverse thread sections from right to left, and the first screw and the second screw are reverse thread screws corresponding to the first and second screw holes.

Preferably, the first screw and the second screw are each provided with an axial through-hole at both ends, and each of the axial through-holes has a non-circular hole section.

Preferably, a boss is provided at one end of the housing, the through hole is formed by axially penetrating the boss, and a screw hole is further radially penetrated through the boss, the screw hole is connected to the through hole and is screwed with a set screw.

Preferably, the ratchet of the clutch block and the control tooth of the driven block are formed by a plurality of inclined protrusions arranged in a ring shape. In particular, when the ratchet and the control tooth are viewed from the front, the inclined protrusions are gradually inclined from left to right.

Compared to prior art, the linkage of the present invention achieves lifting and lowering control of the upper and lower beams of the curtain via the first and second screws, respectively. Not only does this synchronize the upper beam with the lower beam when it moves upward, achieving curtain retraction, but the clutch also provides a gearing linkage and a trip-out mechanism to prevent over-operation of the linkage and synchronous rotation of the first and second rope pullers. This makes curtain opening and closing control more intuitive and convenient, effectively reduces rope tangling and knotting, and significantly improves structural durability and practicality.

[The present invention]

10: Connecting parts

11: Base

111: Lower arc-shaped groove

112: Fits the concave part

113: Lower thread arc segment

114: Arc-shaped retaining wall

115: First engagement stage

116: Second engagement stage

117: Screw hole

118: Grooving

119: Reinforce convex ribs

12: Top cover

121: Upper arc-shaped groove

122: Fitting convex part

123: Upper thread arc segment

124: Arc-shaped retaining wall

125: Piercing hole

126: Grooving

127: Reinforce convex ribs

13: First screw

131: First Block

132: First Stage

133: First Embedment

134: Shaft Perforation

135: Non-circular hole segment

14: Second screw

141: Second Block

142: Second Stage

143: Second inlay

144: Shaft Perforation

145: Non-circular hole segment

15: Braking groove

16: First screw hole

17: Second screw hole

18: Screw

20: Clutch

21: Shell

211: Storage Space

212: Boss

213: Penetration hole

214: Screw hole

215: Set screw

216: Opening

217: Clip-on column

22: Clutch block

221: Thorns

222: Perforation

23: Compression spring

24: Driven block

241: Center axis

242: Tooth Making

30: Curtains

31: On track

32: First Reel

33: Second reel

34: First rope puller

35: Second rope puller

36: First drive shaft

37: Upper beam

38: Second drive shaft

39: Lower beam

Figure 1 is the overall structural diagram of the curtain structure of the present invention.

Figure 2 is a three-dimensional diagram of the linkage and clutch components of the present invention.

Figure 3 is an exploded view of the linkage of the present invention.

Figure 4 is a cross-sectional view of the linkage assembly of the present invention.

Figure 5 is an exploded view of the clutch components of the present invention.

Figure 6 is a cross-sectional view of the clutch assembly of the present invention.

Figure 7 is a schematic diagram of the present invention showing the first pull rope being pulled clockwise to move the upper beam downward.

Figure 8 is a schematic diagram of the clutch actuation when the first pull rope is pulled clockwise.

Figure 9 is a schematic diagram of the linkage of the present invention when the first pull rope is pulled clockwise.

Figure 10 is a schematic diagram of the present invention showing the first pull rope being pulled clockwise to move the upper beam downward to abut against the lower beam.

Figure 11 is a schematic diagram showing the clutch in a disengaged state when the first screw and the second screw of the present invention are engaged and positioned.

Figure 12 is a schematic diagram showing the meshing and positioning of the first screw and the second screw of the present invention.

Figure 13 is a schematic diagram of the present invention showing the first pull rope being pulled counterclockwise to move the upper beam upward.

Figure 14 is a schematic diagram showing the linkage of the linkage components when the first pull rope is pulled counterclockwise.

Figure 15 is a schematic diagram showing the first screw gradually rotating out and away from the second screw when the first pull rope is pulled counterclockwise.

Figure 16 is a schematic diagram of the present invention showing the second pull rope being pulled counterclockwise to move the lower and upper beams upward.

Figure 17 is a schematic diagram showing the clutch in the disengaged state when the second pull rope is pulled counterclockwise.

Figure 18 shows the second screw engaging and driving the first screw when the second pull rope is pulled counterclockwise.

To help you, the Review Committee, gain a deeper understanding of the purpose, features, and efficacy of this invention, please provide the following detailed description with the accompanying diagrams:

First, please refer to Figures 1 to 4 to see a curtain limit linkage device, including a linkage 10 and a clutch 20, wherein: the linkage 10 has a base 11, a top cover 12, a first screw 13 and a second screw 14, the base 11 and the top cover 12 are assembled relative to each other, and define a hollow cylindrical braking channel 15 therebetween. The base 11 and the top cover 12 are provided with a first screw hole 16 and a second screw hole 17 at both ends of the braking channel 15, which are connected and concentric. The apertures of the first and second screw holes 16 and 17 are smaller than the inner diameter of the braking channel 15. The first screw rod 13 is screwed into the first screw hole 16, and one end of the first screw rod 13 has a first baffle 131 and is accommodated in the first screw hole 16. In the braking channel 15, the second screw 14 is screwed into the second screw hole 17, and one end of the second screw 14 has a second baffle 141 and is accommodated in the braking channel. The outer surfaces of the first baffle 131 and the second baffle 141 facing each other are provided with a first step 132 and a second step 142 that can fit each other, and the inner surface of the first baffle 131 is provided with a There is a first embedded portion 133, and the inner surface of the second baffle 141 is provided with a second embedded portion 143. The first screw 13 and the second screw 14 are both provided with an axial through hole 134, 144 at both ends. The axial through holes 134, 144 have a non-circular hole section 135, 145. The clutch 20 has a housing 21, a clutch block 22, a compression spring The housing 21 has a receiving space 211. A boss 212 is provided at the center of one end of the housing 21. A non-circular through-hole 213 is provided axially through the boss 212 and communicates with the receiving space 211. A screw hole 214 is further provided radially through the boss 212. The screw hole 214 communicates with the through-hole 213 and is screwed with a stop. The housing 21 has an opening 216 formed at the other end thereof for the clutch block 22 and the compression spring 23 to be assembled into the accommodating space 211. The housing 21 is also provided with a plurality of latching posts 217 axially disposed on its periphery. One end of the clutch block 22 abuts against the compression spring 23, while the other end is provided with a plurality of ratchets 221. A non-circular through hole 222 is provided through the center. A central shaft 241 is provided on one end of the driven block 24. A plurality of teeth 242 are provided on the surface of the other end and face the clutch block 22. The ratchet 221 of the clutch block 22 and the teeth 242 of the driven block 24 are formed by a plurality of inclined protrusions arranged in a ring shape. In particular, the ratchet 221 and the teeth 242 are arranged in a ring shape. Viewed from the front, the inclined projections (42) are tapered from left to right, allowing the control teeth 242 and the ratchet teeth 221 to engage in the same direction. Finally, the follower block 24 is secured to the opening 216 of the housing 21 via the snap-fit post 217. The clutch 20 is connected to either the first screw 13 or the second screw 14 as the actuator.

Further explanation, the base 11 is concave from top to bottom with a semi-cylindrical lower arc-shaped long groove 111, and then the upper surface of the base 11 is provided with two fitting recesses 112 along the two long sides of the lower arc-shaped long groove 111, and the two short sides of the base 11 are respectively concave with two lower thread arc segments 113 in the shape of semi-circular holes and communicate with the lower arc-shaped long groove 111. The two lower thread arc segments 113 and the lower arc The lower arc-shaped slot 111 is concentric and proportionally smaller, and two arc-shaped baffles 114 are formed at both ends of the lower arc-shaped slot 111. The two arc-shaped baffles 114 are respectively provided with a first engaging step 115 and a second engaging step 116. The first and second engaging steps 115 and 116 are respectively provided to the first embedded portion 133 and the second embedded portion 143 for locking and positioning. The cover 12 is concave from bottom to top with a semi-cylindrical upper arc-shaped long groove 121, and then two fitting protrusions 122 are provided along the two long sides of the upper arc-shaped long groove 121 on the lower surface of the top cover 12. The two end edges of the top cover 12 are respectively concave with two upper thread arc segments 123 in the shape of semi-circular holes and communicate with the upper arc-shaped long groove 121. The two upper thread arc segments 123 are concentric with the upper arc-shaped long groove 121. The upper arc-shaped slot 121 is proportionally smaller, forming two arc-shaped retaining walls 124 at both ends. The top cover 12 is assembled by engaging the two engaging protrusions 122 with the two engaging recesses 112 of the base. Furthermore, the braking channel 15 and the first and second screw holes 16 and 17 connecting the ends of the braking channel 15 are defined between the base 11 and the top cover 12.

Secondly, the two mating recesses 112 of the base 11 are equidistantly provided with a plurality of screw holes 117. The top cover 12 further has a plurality of through-holes 125 equidistantly provided through the two mating protrusions 122 from top to bottom. A plurality of screws 18 are screwed through the through-holes 125 and tightened to the screw holes 117.

Furthermore, at least two slots 118 are formed between the two long sides of the base 11, extending through the surface of the lower arc-shaped slot 111. At least one reinforcing rib 119 is further provided between the two long sides of the base bottom. At least two slots 126 are formed between the two long sides of the top cover 12, extending through the surface of the upper arc-shaped slot 121. At least one reinforcing rib 127 is further provided between the two long sides of the top cover 12.

The composition of the structure is shown in Figures 2 to 5. The first screw 13 and the second screw 14 are firstly mounted on the two lower thread arc segments 113 of the base 11, and the first baffle 131 and the second baffle 141 are placed facing each other in the arc-shaped long groove 111 below the base 11, and then the top cover 12 is assembled on the top of the base 11. The two engaging protrusions 122 are engaged with the two engaging recesses 112 of the base 11 to form a hollow cylindrical braking channel 15 through the lower arc-shaped slot 111 and the upper arc-shaped slot 121. The first screw hole 16 and the second screw hole 17 are formed between the two lower thread arc segments 113 and the two upper thread arc segments 123. The plate 141 is limited in the braking channel 15 and provides the first and second screw rods 13 and 14 with screw displacement through the first and second screw holes 16 and 17. Finally, a plurality of screw members 18 are screwed and tightened through the through-holes 125 and the screw holes 117 to complete the linkage 10. The accommodation space 211 of the clutch 20 is sequentially arranged to accommodate the compression spring 23 and The clutch block 22 is then assembled with the driven block 24 against the opening 216 of the housing 21 and secured with a plurality of snap posts 217. The clutch block 22 is pushed against the driven block 24 by the compression spring 23, and the ratchet 221 engages the stopper 242 to form a toothed linkage or a disengaged idle motion, thereby completing the curtain limit linkage device.

The inner thread sections of the first and second screw holes 16 and 17 form counterclockwise rotating reverse thread sections from right to left, and the first screw rod 13 and the second screw rod 14 form reverse thread screws corresponding to the first and second screw holes 16 and 17. When the first screw rod 13 rotates counterclockwise, the first screw rod 13 is displaced from right to left and gradually rotates out of the braking groove. 15. Conversely, when the screw is rotated clockwise, the first screw 13 is displaced from left to right and gradually screwed into the braking groove 15. When the second screw 14 is rotated counterclockwise, the second screw 14 is displaced from right to left and gradually screwed into the braking groove 15. Conversely, when the screw is rotated clockwise, the second screw 14 is displaced from left to right and gradually screwed out of the braking groove 15.

The embodiment of the assembly of the link 10 and the clutch 20 with the curtain is shown in Figures 1, 5 and 6. The link 10 and the clutch 20 are installed in an upper rail 31 of a curtain 30. The curtain 30 is a curtain structure that adjusts the curtain sheet and curtain cloth by pulling a rope. The upper rail 31 is provided with at least one first rope device 32 and at least one second rope device 33. The clutch 20 is provided with a second reel 33, a first pull rope 34 and a second pull rope 35 for controlling the reeling or unreeling of the first and second reels 32 and 33 respectively. In this embodiment, the clutch 20 is installed between the first screw 13, the first reel 32 and the first pull rope 34, wherein the driven block 24 of the clutch 20 is connected to the first screw 13 by a central shaft 241. The pull rope 34 is connected and a first drive shaft 36 is sequentially passed through the through hole 222 of the clutch block 22, the through hole 213 of the housing 21 and the first reel 32 and then fixed to the non-circular hole section 135 of the first screw 13. The first reel 32 is connected to drive an upper beam 37 of the curtain 30, and further controlled by the first pull rope 34. To raise and lower the beam 37, the second pull rope 35 drives a second drive shaft 38, which then passes through the second reel 33 and the non-circular hole 145 of the second screw 14, securing the second reel 33. The second reel 33 is connected to and drives a lower beam 39 of the curtain 30, further controlling the raising and lowering of the lower beam 39 via the second pull rope 35.

As mentioned above, in actual use of the structure, the curtain 30 is driven by the first and second rope pullers 34 and 35 to drive the first and second rope reels 32 and 33 to retract and release the rope body, and further control the upper beam 37 or the lower beam 39 to move up and down, so as to achieve the purpose of unfolding the curtain or curtain cloth to block light and retracting it to transmit light; as shown in Figure 1, it is a schematic diagram of the lower beam 39 moving down to unfold the curtain cloth to form a light-blocking state. When the upper beam 37 is adjusted to move up to form the upper half of the curtain to transmit light, the curtain is unfolded as shown in Figures 7, 8, and 9. When the first cable puller 34 is pulled clockwise, the tooth 242 of the driven block 24 disengages the ratchet 221 of the clutch block 22. However, the clockwise rotation of the driven block 24 loosens the clutch block 22, allowing the clutch block 22 to rotate by lowering the upper beam 37 under its own weight. Simultaneously, the first drive shaft 36 drives the first screw 13 clockwise, gradually screwing it into the brake channel 15, thereby moving the upper beam 37 downward and allowing light to pass through.

Secondly, when the upper beam 37 moves down to be close to the lower beam 39, as shown in Figures 10, 11, and 12, the first baffle 131 of the first screw 13 and the second baffle 141 of the second screw 14 are close to each other, and the first and second stages 132, 142 are engaged with each other to form a positioning, so that the first screw 13 cannot be When the first pull rope 34 is rotated again, the clutch block 22 will no longer rotate due to the relaxation of the driven block 24. This will cause the driven block 24 to enter an idle state, preventing the first reel 32 from continuously unwinding the line and causing the rope to become tangled and knotted. At the same time, it protects the connecting member 10 from damage due to excessive operation.

Furthermore, when the upper beam 37 is moved upward from the bottom and the curtain is unfolded, as shown in Figures 13, 14, and 15, the first pull rope 34 is pulled counterclockwise. The tooth 242 of the driven block 24 engages the ratchet 221 of the clutch block 22 as it rotates counterclockwise, causing the clutch member 20 to form a linked state. This drives the first reel 32 to reel in the rope via the first drive shaft 36, and simultaneously drives the first screw 13 to rotate counterclockwise, gradually rotating out of the braking channel 15. When the upper beam 37 moves upward to abut the bottom of the upper rail 31, there is no room for further upward movement. Simultaneously, the rope has been completely retracted by the first reel 32, preventing the clutch block 22 from rotating. The compression spring 23 contracts, disengaging the follower block 24. Consequently, if the first reel 34 is continuously pulled counterclockwise, the follower block 24 enters an idle state, preventing the first reel 32 from continuously winding the wire and protecting the linkage 10 from damage due to excessive operation.

In addition, when the lower beam 39 is moved upward and the curtain cloth is folded, the second pull rope 35 is pulled counterclockwise as shown in Figures 16, 17, and 18, and the second drive shaft 38 drives the second reel 33 to reel in the rope, and drives the second screw 14 to rotate counterclockwise and gradually rotate into the braking channel 15. As the second screw 14 reels the curtain cloth, During the process of the second screw 14 being screwed in, the first screw 13 and the first reel 32, the clutch 20 and the first reel 32 are not actuated. Then, when the second screw 14 is gradually screwed in so that the second baffle 141 abuts against the first baffle 131 of the first screw 13 and the first and second stages 132 and 142 are engaged with each other, the second screw 14 is engaged with the first reel 32. When the lower beam 39 has abutted against the upper beam 37 to form the curtain folded state, if the upper beam 37 has not abutted against the upper rail 31 at that time, the first screw 13 will be engaged and driven by the second screw 14 to rotate synchronously counterclockwise, so that the first and second drive shafts 36 and 38 have a synchronous rotation state, further driving the first and second reels 32 and 33 to reel in the ropes, so that This allows the upper beam 37 to gradually move upward along with the lower beam 39. When the clutch block 22 rotates counterclockwise, it disengages from the driven block 24, rendering the clutch 20 inactive and preventing the first cable pull 34 from actuating. This prevents the first cable pull 34 from actuating synchronously and potentially damaging it, thereby improving the durability of the curtain and providing a longer service life.

The structure of the above-described embodiment provides the following benefits: The linkage 10 of the present invention achieves the following lifting and lowering control of the curtain's upper beam 37 and lower beam 39 via the first and second screws 13 and 14, respectively. Not only does it synchronize the upper beam 37 with the lower beam 39 as it moves upward, thereby closing and retracting the curtain, but it also utilizes the clutch 20 to provide a geared linkage and a trip-out mechanism to prevent over-operation of the linkage 10 and further prevent synchronous rotation of the first and second rope pullers 34 and 35. This makes curtain opening and closing control more intuitive and convenient, effectively reduces rope entanglement and knotting, and significantly enhances the structural durability and practicality.

In summary, this invention has indeed achieved a groundbreaking structural design and possesses innovative features. It is also capable of industrial applicability and advancement. Furthermore, this invention has not been previously published and is novel, thus complying with the relevant provisions of the Patent Law. Therefore, we have filed an invention patent application in accordance with the law and sincerely request the Review Board of the Jun Bureau to grant us the legitimate patent rights. We are deeply grateful.

However, the above is merely a preferred embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. In other words, all equivalent changes and modifications made within the scope of the patent application for this invention should still fall within the scope of coverage of this patent.

10: Connecting parts

11: Base

12: Top cover

126: Grooving

127: Reinforcement of convex ribs

13: First screw

14: Second screw

20: Clutch

21: Shell

217: Clip-on column

24: Driven block

241: Center axis

36: First drive shaft

38: Second drive shaft

Claims (8)

A curtain limit linkage device includes a linkage and a clutch, wherein: the linkage has a base, a top cover, a first screw and a second screw; the base and the top cover are assembled relative to each other and define a hollow cylindrical braking channel therebetween; the base and the top cover are provided with a first screw hole and a second screw hole at both ends of the braking channel that are connected and concentric; the apertures of the first and second screw holes are smaller than the inner diameter of the braking channel; the first screw is The first screw is screwed into the first screw hole, and one end of the first screw has a first baffle and is accommodated in the braking channel. The second screw is screwed into the second screw hole, and one end of the second screw has a second baffle and is accommodated in the braking channel. The outer surfaces of the first baffle and the second baffle facing each other are provided with a first step and a second step that can fit each other. The clutch has a housing, a clutch block, a compression spring and a driven block. The housing has an accommodating space. , and a non-circular through-hole is provided at the center of one end to communicate with the accommodation space, and an opening is formed at the other end for the clutch block and the compression spring to be assembled into the accommodation space, and a plurality of snap columns are axially provided on the outer periphery of the shell. One end of the clutch block is against the compression spring, and a plurality of ratchets are provided on the surface of the other end. The clutch block further penetrates a non-circular through-hole in the center, and a central shaft column is protruded at one end of the driven block, and a plurality of ratchets are provided on the surface of the other end. Facing the clutch block, the ratchet of the clutch block and the control tooth of the driven block are formed by a plurality of beveled protrusions arranged in a ring shape. In particular, when viewed from the front, the ratchet and control tooth are gradually inclined from left to right, allowing the control tooth and the ratchet to engage in a unidirectional manner. Finally, the follower block is secured to the opening of the housing via the snap post. The clutch is connected to either the first screw or the second screw to act as an actuator. As described in claim 1, the curtain limiting linkage device, wherein the base is recessed from top to bottom with a semi-cylindrical lower arc-shaped long groove, and two fitting recesses are provided on the upper surface of the base along the two long sides of the lower arc-shaped long groove, and the two short sides of the base are recessed with a first lower thread arc segment in the shape of a semi-circular hole and a second lower thread arc segment connected to the lower arc-shaped long groove, the first and second lower thread arc segments are concentric with the lower arc-shaped long groove and are proportionally smaller, and then two arc-shaped baffles are formed at both ends of the lower arc-shaped long groove, and the two arc-shaped baffles are respectively protruded with a first engaging step and a second engaging step; the top cover is recessed from bottom to top with a semi-cylindrical lower arc-shaped long groove The top cover has a cylindrical upper arc-shaped slot, and two engaging protrusions are provided on the lower surface of the top cover along the two long sides of the upper arc-shaped slot. A first upper thread arc segment and a second upper thread arc segment are recessed in the two end edges of the top cover, respectively, in the shape of semicircular holes, communicating with the upper arc-shaped slot. The first and second upper thread arc segments are concentric with the upper arc-shaped slot and are proportionally smaller, thereby forming two arc-shaped retaining walls at the two ends of the upper arc-shaped slot. The top cover is assembled by the two engaging protrusions engaging with the two engaging recesses of the base. The braking channel and the first and second screw holes communicating with the two ends of the braking channel are further defined between the base and the top cover. The curtain limit linkage device as described in claim 2, wherein the two engaging recessed surfaces of the base are provided with a plurality of screw holes at equal intervals, and the top cover is further provided with a plurality of through-holes at equal intervals through the two engaging protruding portions from top to bottom, and a plurality of screws are screwed through the through-holes and into the screw holes. The curtain limiting linkage device as described in claim 2, wherein at least two slots are formed between the two long sides of the base, penetrating the surface of the lower arc-shaped elongated groove; at least one reinforcing rib is further provided between the two long sides of the base bottom; at least two slots are formed between the two long sides of the top cover, penetrating the surface of the upper arc-shaped elongated groove; at least one reinforcing rib is further provided between the two long sides of the top cover. The curtain limiting linkage device according to claim 2, wherein the inner surface of the first baffle of the first screw is provided with a first embedded portion, and the inner surface of the second screw is provided with a second embedded portion, wherein the first and second embedded portions respectively correspond to the first engaging step and the second engaging step to form a position. The curtain limiting linkage device as described in claim 1, wherein the internal thread segments of the first and second screw holes form reverse-threaded segments that rotate counterclockwise from right to left, and the first and second screw rods form reverse-threaded screw rods corresponding to the first and second screw holes. The curtain limit linkage device as described in claim 1, wherein the first screw and the second screw are each provided with an axial through-hole at both ends, and each of the axial through-holes has a non-circular hole section. The curtain limit linkage device as described in claim 1, wherein a boss is provided at one end of the housing, the through hole is formed by axially penetrating the boss, and a screw hole is further radially penetrated through the boss, the screw hole communicates with the through hole and is threaded with a set screw.