CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to U.S. provisional patent application no. 63/370,872 filed on August 9, 2022, the disclosure of which is hereby incorporated by reference.

BACKGROUND

[0002] 1. Field of the Invention

[0003] The present invention relates to window shades, and actuating systems used in window shades.

[0004] 2. Description of the Related Art

[0005] Some window shades may use an operating cord for raising a bottom part of the window shade and a wand for lowering the bottom part. More specifically, the operating cord may be pulled downward to drive a rotary part in rotation, which can be transmitted to a drive axle so that the drive axle can rotate for winding a suspension cord connected with the bottom part. When a user rotates the wand, an arrester coupled to the wand can release the drive axle, which can accordingly rotate as the bottom part lowers under gravity action.

[0006] In the aforementioned type of window shades, the braking force of the arrester may create resistance against the rotation of the drive axle when the rotary part and the drive axle rotate for raising the bottom part. As a result, the pulling force applied by the user has to overcome the braking force to be able to raise the bottom part, which may require increased effort from the user.

SUMMARY

[0007] The present application describes a window shade and an actuating system for use with the window shade that can reduce internal friction and can be conveniently operated with reduced effort.

[0008] According to an embodiment, an actuating system for a window shade includes a transmission axle rotatable about a longitudinal axis thereof, a braking spring having an engaged state adapted to prevent rotation of the transmission axle and a release state allowing rotation of the transmission axle, a brake actuating mechanism coupled to the braking spring and including a switching actuator operable between a first and a second position to switch the braking spring between the engaged state and the release state, wherein the first position of the switching actuator corresponds to the engaged state, and the second position of the switching actuator corresponds to the release state, and a detent mechanism coupled to the brake actuating mechanism. The detent mechanism is switchable between a first biasing state where the detent mechanism applies a first biasing force that assists in keeping the switching actuator in the first position, and a second biasing state where the detent mechanism applies a second biasing force that assists in keeping the switching actuator in the second position.

[0009] Moreover, the present application provides a window shade that can incorporate the actuating system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a perspective view illustrating an embodiment of a window shade;

[0011] FIG. 2 is a perspective view illustrating the window shade of FIG. 1 having a movable rail lowered from a head rail;

[0012] FIG. 3 is an exploded view illustrating the construction of a control module provided in an actuating system for a window shade;

[0013] FIG. 4 is a cross-sectional view of the control module shown in FIG. 3;

[0014] FIG. 5 is an exploded view illustrating construction details of a clutching mechanism provided in the control module;

[0015] FIGS. 6 and 7 are partial cross-sectional views illustrating an example of a sliding connection between a clutching part of the clutching mechanism and a spool of a lift actuating module;

[0016] FIG. 8 is a schematic view illustrating a portion of the control module including the connection between a braking spring and a spring coupler and a transmission assembly that connects a switching actuator to the spring coupler;

[0017] FIG. 9 is an enlarged perspective view illustrating a detent mechanism provided in the control module in a first biasing state;

[0018] FIG. 10 is a schematic view illustrating the detent mechanism in the first biasing state; [0019] FIG. 11 is an enlarged perspective view illustrating the detent mechanism in a second biasing state;

[0020] FIG. 12 is a schematic view illustrating the detent mechanism in the second biasing state;

[0021] FIGS. 13 and 14 are schematic views illustrating exemplary operation for expanding the window shade of FIG. 1 ;

[0022] FIGS. 15 and 16 are schematic views illustrating exemplary operation for raising the movable rail of the window shade of FIG. 1;

[0023] FIG. 17 is an exploded view illustrating a variant construction of a control module provided in an actuating system for a window shade;

[0024] FIG. 18 is an enlarged view illustrating some construction details of a transmission assembly provided in the control module shown in FIG. 17; and

[0025] FIGS. 19 and 20 are schematic views illustrating exemplary operation for expanding a window shade provided with the control module shown in FIG. 17.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] FIGS. 1 and 2 are perspective views illustrating an embodiment of a window shade 100 in different states. Referring to FIGS. 1 and 2, the window shade 100 can include a head rail 102, a movable rail 104, a shading structure 106 and an actuating system 200. The window shade 100 is shown in a retracted or raised state in FIG. 1, and in an expanded or lowered state in FIG. 2.

[0027] The head rail 102 may be affixed at a top of a window frame, and can have any desirable shapes. According to an example of construction, the head rail 102 can have an elongate shape including a cavity for at least partially receiving the actuating system 200 of the window shade 100.

[0028] The movable rail 104 can be suspended from the head rail 102 with a plurality of suspension elements 110 (shown with phantom lines in FIG. 2). According to an example of construction, the movable rail 104 may be an elongate rail having a channel adapted to receive to the attachment of the shading structure 106. Examples of the suspension elements 110 may include, without limitation, cords, strips, bands, and the like. According to an example, the movable rail 104 may be a bottom rail of the window shade 100. However, it will be appreciated that other shade elements may be provided below the movable rail 104 as needed. [0029] The shading structure 106 is disposed between the head rail 102 and the movable rail 104, and may have any suitable structure that can be expanded and collapsed between the head rail 102 and the movable rail 104. According to an example of construction, the shading structure 106 can have a cellular structure, which may include, without limitation, honeycomb structures. During use, the shading structure 106 can be suspended from the head rail 102, and can be expanded or collapsed by displacing the movable rail 104 away from or toward the head rail 102.

[0030] Referring to FIGS. 1 and 2, the movable rail 104 can move vertically relative to the head rail 102 for setting the window shade 100 to a desirable configuration. For example, the movable rail 104 may be raised toward the head rail 102 to collapse the shading structure 106 as shown in FIG. 1, or lowered away from the head rail 102 to expand the shading structure 106 as shown in FIG. 2. The vertical position of the movable rail 104 relative to the head rail 102 may be controlled with the actuating system 200.

[0031] Referring to FIGS. 1 and 2, the actuating system 200 is assembled with the head rail 102, and is operable to displace the movable rail 104 relative to the head rail 102 for adjustment. The actuating system 200 can include a transmission axle 202, a plurality of winding units 204 rotationally coupled to the transmission axle 202, and a control module 206 coupled to the transmission axle 202.

[0032] The transmission axle 202 and the winding units 204 can be assembled with the head rail 102. The transmission axle 202 is coupled to the winding units 204, and can rotate about a longitudinal axis 208 of the transmission axle 202. Each of the winding units 204 is connected to the movable rail 104 via at least one suspension element 110, and is operable to wind the suspension element 110 for raising the movable rail 104 and to unwind the suspension element 110 for lowering the movable rail 104. For example, the winding unit 204 may include a rotary drum (not shown) that is rotationally coupled to the transmission axle 202 and is connected to one end of the suspension element 110, and another end of the suspension element 110 can be connected to the movable rail 104, whereby the rotary drum can rotate along with the transmission axle 202 to wind or unwind the suspension element 110. Since the winding units 204 are commonly coupled to the transmission axle 202, the winding units 204 can operate in a concurrent manner for winding and unwinding the suspension elements 110.

[0033] The control module 206 is coupled to the transmission axle 202, and is operable to cause the transmission axle 202 to rotate in either direction about the longitudinal axis 208 for raising or lowering the movable rail 104. In conjunction with FIGS. 1 and 2, FIG. 3 is an exploded view illustrating a construction of the control module 206, and FIG. 4 is a cross-sectional view of the control module 206.

[0034] Referring to FIGS. 1-4, the control module 206 can include a housing 210 that can be affixed to the head rail 102. The housing 210 can have a cavity 210A adapted to receive at least some component parts of the control module 206. According to an example of construction, the housing 210 may include two casing portions 212A and 212B that are attached to each other to define at least partially the cavity 210A, and a cover 212C and a bracket 212D that may be affixed to the casing portion 212A to close the cavity 210A at one side thereof.

[0035] Referring to FIGS. 3 and 4, the control module 206 can include an axle adapter 214, a braking spring 216, a brake engaging part 218, a lift actuating module 220 and a clutching mechanism 222, all of which can be assembled with the housing 210.

[0036] For facilitating the assembly of the different component parts, the housing 210 can include a fixed shaft 224 having multiple sections of different sizes. According to an example of construction, the fixed shaft 224 can include a lug 226 fixedly connected to the bracket 212D, and a shaft portion 228 fixedly attached to the lug 226. The lug 226 and the shaft portion 228 can be substantially coaxial to the longitudinal axis 208. It will be appreciated that the lug 226 and the shaft portion 228 may also be provided as a single part, which can be attached to or formed integrally with the bracket 212D.

[0037] The axle adapter 214 can be received at least partially inside the cavity 210A of the housing 210, and can extend outward through the casing portion 212B. According to an example of construction, the axle adapter 214 may be provided as a unitary part of an elongate shape. The axle adapter 214 may be pivotally connected about the fixed shaft 224 with the shaft portion 228 thereof inserted into a hole 230 provided in the axle adapter 214. [0038] The axle adapter 214 is rotationally coupled to the transmission axle 202 so that the transmission axle 202 and the axle adapter 214 can rotate in unison about the longitudinal axis 208 relative to the housing 210. For example, an end of the transmission axle 202 can be inserted into the hole 230 at a side of the axle adapter 214 opposite to the fixed shaft 224. A fastener (not shown) may be used to securely attach the transmission axle 202 to the axle adapter 214. Accordingly, the axle adapter 214 can be rotationally coupled to the winding units 204 via the transmission axle 202, and the transmission axle 202 and the axle adapter 214 can rotate in unison about the longitudinal axis 208 for raising and lowering the movable rail 104.

[0039] The braking spring 216 has an engaged state adapted to prevent rotation of the transmission axle 202, and a release state allowing rotation of the transmission axle 202. More specifically, the braking spring 216 can apply a braking force adapted to prevent rotation of the brake engaging part 218 in the engaged state. According to an example of construction, the braking spring 216 and the brake engaging part 218 are disposed around the longitudinal axis 208. For example, the brake engaging part 218 can have a hollow interior 232 and can be disposed around an intermediate portion of the axle adapter 214, which passes through the hollow interior 232 leaving a gap between the intermediate portion of the axle adapter 214 and the brake engaging part 218. During operation, the axle adapter 214 thus can rotate relative to the brake engaging part 218.

[0040] The braking spring 216 can be disposed around the brake engaging part 218 in contact with an outer surface 234 thereof, and can apply a braking force on the brake engaging part 218 for preventing rotation of the brake engaging part 218 about the longitudinal axis 208. For example, the outer surface 234 may be defined on a ring portion of the brake engaging part 218, and the braking spring 216 can include a torsion spring mounted around the ring portion of the brake engaging part 218 in frictional contact with the outer surface 234. In the engaged state, the braking spring 216 can tighten and apply a braking force on the brake engaging part 218 via the frictional contact between the braking spring 216 and the outer surface 234 of the brake engaging part 218. In the release state, the braking spring 216 can expand so as to loosen the frictional contact between the braking spring 216 and the outer surface 234 of the brake engaging part 218. [0041] Referring to FIGS. 3 and 4, the lift actuating module 220 can include a spool 236 connected to an operating part 238, and a spring 240 connected to the spool 236. The operating part 238 can be a flexible element of a linear shape, and can have an end anchored to the spool 236. Examples of the operating part 238 can include, without limitation, a cord or a tape. The spool 236 is pivotally connected to the housing 210, and is rotatable in a winding direction to wind the operating part 238 and in an unwinding direction to unwind the operating part 238. According to an example of construction, the spool 236 may be pivotally connected around the fixed shaft 224, whereby the spool 236 can rotate about the longitudinal axis 208 for winding and unwinding the operating part 238.

[0042] The spring 240 is connected to the spool 236, and is adapted to bias the spool 236 to rotate in the winding direction. According to an example of construction, the spool 236 can have a cavity 242 through which passes the fixed shaft 224, and the spring 240 can be disposed around the fixed shaft 224 inside the cavity 242 with two ends of the spring 240 being respectively connected to the fixed shaft 224 (e.g., at the lug 226) and the spool 236. The lift actuating module 220 may be operable to raise the movable rail 104 by pulling the operating part 238 so that the spool 236 rotates in the unwinding direction. When the operating part 238 is released, the spring 240 can urge the spool 236 to rotate for winding at least partially the operating part 238.

[0043] The clutching mechanism 222 is configured to selectively couple the axle adapter 214 to either one of the lift actuating module 220 and the brake engaging part 218, wherein the clutching mechanism 222 is operable to couple the axle adapter 214 to the spool 236 of the lift actuating module 220 and decouple the axle adapter 214 from the brake engaging part 218 in response to a rotation of the spool 236 in the unwinding direction, and decouple the axle adapter 214 from the spool 236 and couple the axle adapter 214 to the brake engaging part 218 when the spool 236 rotates in the winding direction. Accordingly, the axle adapter 214 and the spool 236 can concurrently rotate relative to the brake engaging part 218 free of the braking force applied by the braking spring 216, when the spool 236 rotates in the unwinding direction. This may facilitate raising of the movable rail 104 and reduce friction between component parts. When the spool 236 rotates in the winding direction, the braking force of the braking spring 216 in the engaged state can be exerted through the brake engaging part 218 and the clutching mechanism 222 to the axle adapter 214, and thus is adapted to prevent a rotation of the axle adapter 214 and the transmission axle 202. The movable rail 104 can be thereby held at a desired position relative to the head rail 102. As described hereinafter, the clutching mechanism 222 can include two clutching parts 244 and 246 that are movable relative to the brake engaging part 218 and the spool 236 to selectively couple the axle adapter 214 to either one of the spool 236 and the brake engaging part 218.

[0044] In conjunction with FIGS. 3 and 4, FIG. 5 is an exploded view illustrating some construction details of the clutching mechanism 222. Referring to FIGS. 3-5, the brake engaging part 218 and the clutching part 244 can be disposed around an intermediate portion 248 of the axle adapter 214, and the other clutching part 246 can be disposed adjacent to an end 250 of the axle adapter 214. The clutching part 244 can be coupled to the brake engaging part 218, and is movable relative to the axle adapter 214 and the brake engaging part 218 between a disengaged position where the clutching part 244 is disengaged from the axle adapter 214 and an engaged position where the clutching part 244 is engaged with the axle adapter 214. The clutching part 246 can be coupled to the spool 236, and is movable relative to the axle adapter 214 and the spool 236 between a disengaged position where the clutching part 246 is disengaged from the axle adapter 214 and an engaged position where the clutching part 246 is engaged with the axle adapter 214.

[0045] The controlled movements of the two clutching parts 244 and 246 allow to switch the coupling state of the axle adapter 214 with respect to the brake engaging part 218 and the spool 236 of the lift actuating module 220. More specifically, the clutching mechanism 222 is configured so that a rotation of the spool 236 in the unwinding direction causes the clutching part 246 to move to the engaged position and causes the clutching part 244 to move to the disengaged position, whereby the spool 236, the axle adapter 214 and the clutching part 246 are concurrently rotatable relative to the brake engaging part 218. Moreover, the clutching mechanism 222 is configured so that a rotation of the spool 236 in the winding direction causes the clutching part 246 to move to the disengaged position, and the clutching part 244 can be switched to the engaged position while the clutching part 246 is disengaged from the axle adapter 214 so that the braking force of the braking spring 216 is adapted to prevent a rotation of the axle adapter 214. [0046] Each of the clutching parts 244 and 246 may be a single movable part. According to an example of construction, the two clutching parts 244 and 246 are configured to slide along the longitudinal axis 208 in opposite directions to selectively couple the axle adapter 214 to either one of the spool 236 and the brake engaging part 218. For example, the clutching part 244 can have a ring shape, and the intermediate portion 248 of the axle adapter 214 can be disposed through the clutching part 244 so that the clutching part 244 can slide along the intermediate portion 248 relative to the axle adapter 214. The clutching part 246 can likewise have a ring shape, and can be disposed to slide along the shaft portion 228 of the fixed shaft 224.

[0047] Referring to FIGS. 3-5, the clutching part 244 is coupled to the brake engaging part 218, and is movable between the disengaged position and the engaged position in sliding contact with the brake engaging part 218. According to an example of construction, the clutching part 244 can be disposed around the intermediate portion 248 of the axle adapter 214 and at least partially received in the hollow interior 232 of the brake engaging part 218. The connection between the brake engaging part 218 and the clutching part 244 allows a limited displacement of the clutching part 244 relative to the brake engaging part 218 between the disengaged position and the engaged position. To this end, the clutching part 244 can be in sliding contact with the brake engaging part 218 inside the hollow interior 232 via at least one ramp surface provided on the clutching part 244 or the brake engaging part 218. For example, the clutching part 244 can have a notch 252 disposed eccentric from the longitudinal axis 208, and an inner wall 254 of the brake engaging part 218 at least partially delimiting the hollow interior 232 thereof can have a protrusion 256 that is restricted to slide within the notch 252. The notch 252 of the clutching part 244 can include a ramp surface 258 extending between two stop surfaces 260 A and 260B, the protrusion 256 of the brake engaging part 218 can have a ramp surface 262 extending between two stop surfaces 264A and 264B, and the clutching part 244 can be disposed with the ramp surface 258 in sliding contact with the ramp surface 262.

[0048] With the aforementioned construction, the clutching part 244 can move relative to the brake engaging part 218 between the disengaged position and the engaged position with the ramp surface 258 in sliding contact with the ramp surface 262. More specifically, the clutching part 244 can concurrently rotate about and slide along the longitudinal axis 208 for switching between the disengaged position and the engaged position, the protrusion 256 of the brake engaging part 218 being displaced between the two stop surfaces 260A and 260B of the notch 252 during the movement of the clutching part 244 relative to the brake engaging part 218. When the clutching part 244 is in the disengaged position, the axle adapter 214 is rotatable about the longitudinal axis 208 while the brake engaging part 218 and the clutching part 244 remain generally stationary. When the clutching part 244 is in the engaged position, the axle adapter 214 and the clutching part 244 are rotationally coupled to each other, and the braking force applied by the braking spring 216 on the brake engaging part 218 is adapted to prevent a rotation of the axle adapter 214 and the clutching part 244 via a contact between the stop surface 260A of the clutching part 244 and the stop surface 264A of the brake engaging part 218.

[0049] Referring to FIGS. 3-5, the axle adapter 214 can include a plurality of teeth 266 disposed around the longitudinal axis 208, and the clutching part 244 can include a plurality of teeth 268 disposed around the longitudinal axis 208. The teeth 268 can be engaged with the teeth 266 when the clutching part 244 is in the engaged position, and disengaged from the teeth 266 when the clutching part 244 is in the disengaged position. The teeth 266 may be disposed along a first circumference of the axle adapter 214 at an end of its intermediate portion 248, and the teeth 268 may be disposed along a circular edge of the clutching part 244 that extends around the intermediate portion 248 facing the teeth 266 of the axle adapter 214. The teeth 266 and 268 may have a saw-tooth pattern. When the clutching part 244 is in the engaged position, the engagement between the teeth 266 and 268 allows torque transmission from the axle adapter 214 to the clutching part 244 in only one direction R1 and allows rotation of the axle adapter 214 relative to the clutching part 244 in a direction R2 opposite to the direction Rl. The direction R1 corresponds to a direction of rotation that would move the stop surface 260A of the clutching part 244 toward the stop surface 264A of the brake engaging part 218. A torque in the direction Rl can be created by the suspended load of the movable rail 104. When the clutching part 244 is in the engaged position, the braking force of the braking spring 216 can oppose a torque in the direction Rl to hold the movable rail 104 in position. When the axle adapter 214 rotates in the direction R2, the configuration of the teeth 266 and 268 is so that the axle adapter 214 can push the clutching part 244 to move away from the engaged position to the disengaged position.

[0050] Referring to FIGS. 3-5, the clutching part 246 is coupled to the spool 236 of the lift actuating module 220, and is movable between the disengaged position and the engaged position in sliding contact with the spool 236. According to an example of construction, the clutching part 246 can be disposed around the shaft portion 228 and at least partially received in a hollow interior of the spool 236. The clutching part 246 can be coupled to the spool 236 via a sliding connection configured so that a rotation of the spool 236 in the unwinding direction (i.e., for unwinding the operating part 238) causes the clutching part 246 to slide toward the axle adapter 214 to the engaged position, and a rotation of the spool 236 in the winding direction (i.e., for winding the operating part 238) causes the clutching part 246 to slide away from the axle adapter 214 to the disengaged position. The sliding connection between the spool 236 and the clutching part 246 can be carried out via at least one ramp surface provided on the clutching part 246 or the spool 236.

[0051] FIGS. 6 and 7 are partial cross-sectional views illustrating an example of a sliding connection between the spool 236 and the clutching part 246. Referring to FIGS. 3-7, the clutching part 246 can have a ramp surface 270 radially distant from the longitudinal axis 208, and the spool 236 can have a protrusion 272 in sliding contact with the ramp surface 270. The ramp surface 270 may be exemplary defined on an edge of a slot 270A provided on a circumferential surface of the clutching part 246, and the protrusion 272 may be provided on an inner wall of the spool 236. It will be appreciated the sliding connection may also be achieved by providing the ramp surface 270 on the spool 236 and the protrusion 272 on the clutching part 246. Through the sliding connection, the clutching part 246 can concurrently rotate about and slide along the longitudinal axis 208 for switching between the disengaged position and the engaged position in response to a rotation of the spool 236. The clutching part 246 is shown in the disengaged position in FIG. 6 and in the engaged position in FIG. 7.

[0052] As shown in FIGS. 3 and 4, the clutching part 246 may be connected to a torsion spring 274 that is disposed tightly around the shaft portion 228. The torsion spring 274 can provide some resistance for assisting in keeping the clutching part 246 in the disengaged position. [0053] Referring to FIGS. 3-7, the axle adapter 214 can include a plurality of teeth 276 disposed around the longitudinal axis 208 axially spaced apart from the teeth 266, and the clutching part 246 can include a plurality of teeth 278 disposed around the longitudinal axis 208. The teeth 278 can be engaged with the teeth 276 when the clutching part 246 is in the engaged position, and disengaged from the teeth 276 when the clutching part 246 is in the disengaged position. The teeth 276 may be disposed along a second circumference of the axle adapter 214 at another end of its intermediate portion 248 that is smaller than the first circumference along which are disposed the teeth 266. The teeth 276 and 278 may have a saw-tooth pattern. When the clutching part 246 is in the engaged position, the engagement between the teeth 276 and 278 allows torque transmission from the spool 236 and the clutching part 246 to the axle adapter 214 in only the direction R2 and allows rotation of the spool 236 and the clutching part 246 relative to the axle adapter 214 in the direction Rl.

[0054] Exemplary operation of the clutching mechanism 222 is described hereinafter with reference to FIGS. 3-7. Supposing that the clutching part 244 is in the engaged position and the clutching part 246 in the disengaged position, which corresponds to a state of the clutching mechanism 222 in which the axle adapter 214 is coupled to the brake engaging part 218 and decoupled from the spool 236. By pulling the operating part 238, the spool 236 can be rotated in the unwinding direction corresponding to the direction R2, which causes the clutching part 246 to slide in a direction DI from the disengaged position to the engaged position so that the axle adapter 214 is rotationally coupled to the spool 236 via the clutching part 246 for rotation in the direction R2. Owing to the configuration of the teeth 266 and 268, the coupled rotation of the spool 236 and the axle adapter 214 in the direction R2 then can urge the clutching part 244 to slide in a direction D2 opposite to the direction DI from the engaged position to the disengaged position, whereby the axle adapter 214 can be decoupled from the brake engaging part 218. Accordingly, the clutching mechanism 222 can be switched to a state in which the axle adapter 214 is decoupled from the brake engaging part 218 and coupled to the spool 236 for rotation in the direction R2. In this state, the braking force of the braking spring 216 in the engaged state no longer applies on the axle adapter 214. While the brake engaging part 218 and the clutching part 244 remain generally stationary, the spool 236, the clutching part 246, the axle adapter 214 and the transmission axle 202 can rotate concurrently for raising the movable rail 104.

[0055] When the operating part 238 is released after it has been extended from the spool 236, the spring 240 can bias the spool 236 to rotate in the winding direction corresponding to the direction R1 for retracting the operating part 238. The rotation of the spool 236 in the direction R1 causes the clutching part 246 to slide in the direction D2 from the engaged position to the disengaged position so that the axle adapter 214 is rotationally decoupled from the spool 236. The suspended load of the movable rail 104 then may cause the axle adapter 214 to rotate in the direction Rl. Owing to the sliding contact between the ramp surface 258 of the clutching part 244 and the ramp surface 262 of the brake engaging part 218 and a frictional contact between the axle adapter 214 and the clutching part 244, the rotational displacement of the axle adapter 214 in the direction Rl causes the clutching part 244 to rotate and slide in the direction DI from the disengaged position to the engaged position so that the axle adapter 214 is coupled to the brake engaging part 218 via the clutching part 244. As a result, the clutching mechanism 222 can be switched to a state in which the axle adapter 214 is coupled to the brake engaging part 218 and decoupled from the spool 236. In this state, the braking force of the braking spring 216 in the engaged state can apply on the axle adapter 214 to prevent its rotation in the direction Rl, whereby the movable rail 104 can be held in position relative to the head rail 102 while the spool 236 rotates in the direction Rl for winding the operating part 238.

[0056] In the clutching mechanism 222 described herein, the clutching part 244 thus can slide in the direction D 1 and the clutching part 246 in the opposite direction D2 to rotationally couple the axle adapter 214 to the brake engaging part 218 and at the same time rotationally decouple the axle adapter 214 with respect to the spool 236. Conversely, the clutching part 244 can slide in the direction D2 and the clutching part 246 in the opposite direction DI to rotationally couple the axle adapter 214 to the spool 236 and at the same time rotationally decouple the axle adapter 214 with respect to the brake engaging part 218. Since the axle adapter 214 is coupled to only one of the brake engaging part 218 and the spool 236 at a time, undesirable friction between the axle adapter 214 and the brake engaging part 218 can be prevented when the axle adapter 214 rotates along with the spool 236. [0057] Referring to FIGS. 1-4 and 8, the control module 206 further includes a brake actuating mechanism 302. The brake actuating mechanism 302 is coupled to the braking spring 216, and includes a switching actuator 306 that is movably connected to the housing 210 and has at least a first and a second position. The switching actuator 306 is operable between the first and the second position to switch the braking spring 216 between the engaged state and the release state, wherein the first position of the switching actuator 306 corresponds to the engaged state of the braking spring 216, and the second position of the switching actuator 306 corresponds to the release state of the braking spring 216.

[0058] Referring to FIGS. 1-4 and 8, the brake actuating mechanism 302 can include the switching actuator 306, and a spring coupler 308 connected to the braking spring 216, the switching actuator 306 being connected to the spring coupler 308 via a transmission assembly 310. The braking spring 216 can be mounted in frictional contact with the outer surface 234 of the brake engaging part 218 as described previously, and can have two ends 216A and 216B respectively connected to the housing 210 and the spring coupler 308.

[0059] The spring coupler 308 is configured to be movable for switching the braking spring 216 between the engaged state and the release state. According to an example of construction, the spring coupler 308 can be disposed for rotation about the longitudinal axis 208 to urge the braking spring 216 to switch between the engaged state and the release state. For example, the spring coupler 308 can have a ring shape pivotally disposed around the intermediate portion 248 of the axle adapter 214. The spring coupler 308 is thereby rotatable relative to the axle adapter 214 to displace the end 216B of the braking spring 216 either in a direction that urges the braking spring 216 to enlarge and loosen its frictional contact with the brake engaging part 218, or in an opposite direction that causes the braking spring 216 to tighten its frictional contact with the brake engaging part 218.

[0060] The switching actuator 306 is operable to urge the spring coupler 308 to move for switching braking spring 216 between the engaged state and the release state. The switching actuator 306 may include any structures that can facilitate manual operation. For example, the switching actuator 306 may include a wand that extends along a lengthwise axis Y and is exposed for operation. The operating part 238 may be threaded through a hollow interior of the wand of the switching actuator 306, and may have an end anchored to a handle 312. The handle 312 is disposed adjacent to a distal end of the switching actuator 306, and can be pulled away from the switching actuator 306 for extending the operating part 238 from the spool 236. A guide element 287 may be provided inside the housing 210 for guiding the operating part 238.

[0061] Referring to FIGS. 3, 4 and 8, the transmission assembly 310 includes a plurality of transmission elements through which the switching actuator 306 is connected to the spring coupler 308. The transmission assembly 310 is configured so that an actuating movement of the switching actuator 306 can be transmitted through the transmission assembly 310 to urge the spring coupler 308 to move for switching the braking spring 216 between the engaged state and the release state.

[0062] According to an example of construction, the connection between the switching actuator 306 and the housing 210 allows rotation of the switching actuator 306 about the lengthwise axis Y thereof relative to the housing 210, and the transmission elements of the transmission assembly 310 are configured to convert a rotational movement of the switching actuator 306 about the lengthwise axis Y into a rotation of the spring coupler 308 about the longitudinal axis 208. For example, the transmission assembly 310 can include two transmission elements 314 and 316, which can include gear elements. The transmission element 316 has a gear portion 316A, is pivotally connected to the housing 210 about a pivot axis 316R, and is pivotally connected to the switching actuator 306. The transmission element 314 has two gear portions 314A and 314B, and is pivotally assembled inside the housing 210 about a pivot axis 314R. The gear portion 316A of the transmission element 316 is engaged with the gear portion 314A of the transmission element 314, and the gear portion 314B of the transmission element 314 is engaged with a gear portion 308A provided on the spring coupler 308. The two transmission elements 314 and 316 may be disposed so as to respectively rotate about the two pivot axes 314R and 316R that are perpendicular to each other, the pivot axis 314R of the transmission element 314 being parallel to the longitudinal axis 208, and the pivot axis 316R of the transmission element 316 being tilted an angle relative to a vertical direction. With the arrangement described herein, a rotational displacement of the switching actuator 306 about the lengthwise axis Y can be transmitted through the transmission assembly 310 to the spring coupler 308, which causes the spring coupler 308 to rotate and urge the braking spring 216 to switch between the engaged state and the release state. Moreover, the pivotal connection between the transmission element 316 and the switching actuator 306 allows to modify the inclination of the switching actuator 306 for facilitating its operation.

[0063] Referring to FIGS. 3 and 9-12, the control module 206 further includes a detent mechanism 320 that is coupled to the brake actuating mechanism 302 and is switchable between a first biasing state and a second biasing state. In the first biasing state, the detent mechanism 320 applies a first biasing force Fl (better shown in FIG. 10) that assists in keeping the switching actuator 306 in the first position. In the second biasing state, the detent mechanism 320 applies a second biasing force F2 (better shown in FIG. 12) that assists in keeping the switching actuator 306 in the second position. More specifically, the detent mechanism 320 can include a spring 322 that is configured to be loaded as the switching actuator 306 moves between the first position and the second position, and to apply the first biasing force Fl when the switching actuator 306 is in the first position and to apply the second biasing force F2 when the switching actuator 306 is in the second position.

[0064] Referring to FIGS. 3 and 9-12, the detent mechanism 320 can be coupled to the transmission element 314, and each of the first biasing force Fl and the second biasing force F2 is an off-axis force applied on the transmission element 314. More specifically, the transmission element 314 can have an eccentric portion 324, and the detent mechanism 320 can apply the first biasing force Fl or the second biasing force F2 on the eccentric portion 324 of the transmission element 314. The eccentric portion 324 is fixedly connected to the transmission element 314 so that the eccentric portion 324 is movable along with the transmission element 314 around the pivot axis 314R. According to an example of construction, the eccentric portion 324 may be formed integrally with the transmission element 314.

[0065] Referring to FIGS. 3 and 9-12, the detent mechanism 320 can include a pivoting element 326, a link element 328 and the spring 322. The pivoting element 326 is configured to rotate about a pivot axis 326R. The link element 328 is pivotally connected to the eccentric portion 324 of the transmission element 314, and is configured to slide radially relative to the pivot axis 326R of the pivoting element 326. The spring 322 is connected to the pivoting element 326 and the link element 328, and is configured to apply the first biasing force Fl or the second biasing force F2.

[0066] The pivoting element 326 can be pivotally connected to the housing 210 about the pivot axis 326R. The pivot axis 326R of the pivoting element 326 is parallel to and spaced apart from the pivot axis 314R of the transmission element 314.

[0067] The link element 328 is slidably connected to the pivoting element 326, and is pivotally connected to the eccentric portion 324 of the transmission element 314 about a pivot axis 328R. According to an example of construction, the link element 328 may be a rod having a first and a second end, the first end being slidably connected to the pivoting element 326, and the second end being pivotally connected to the eccentric portion 324 of the transmission element 314.

[0068] The spring 322 can have one end connected to the pivoting element 326, and another end connected to the link element 328. According to an example of construction, the spring 322 may be a compression spring disposed around the link element 328, the spring 322 being connected to a flange provided on the link element 328. During operation, the spring 322 can generate an elastic force that applies as the first biasing force Fl or the second biasing force F2 to the eccentric portion 324 of the transmission element 314.

[0069] Exemplary operation of the detent mechanism 320 is described hereinafter with reference to FIGS. 3 and 9-12. When the switching actuator 306 moves between the first position and the second position, the transmission element 314 can rotate about the pivot axis 314R, the link element 328 can concurrently rotate relative to the transmission element 314 about the pivot axis 328R and slide relative to the pivoting element 326, and the pivoting element 326 can rotate about the pivot axis 326R relative to the housing 210. The movement of the switching actuator 306 between the first position and the second position can displace the pivot axis 328R of the link element 328 across a line L joining the pivot axis 314R of the transmission element 314 and the pivot axis 326R of the pivoting element 326, and can switch the detent mechanism 320 between the first biasing state and the second biasing state.

[0070] Referring to FIGS. 9 and 10, when the detent mechanism 320 is in the first biasing state corresponding to the first position of the switching actuator 306, the pivot axis 328R of the link element 328 is located at a first side of the line L. In the first biasing state, the first biasing force Ft applied by the spring 322 is located at the first side of the line L, and assists in keeping the switching actuator 306 in the first position and the braking spring 216 in the engaged state.

[0071] Referring to FIGS. 11 and 12, when the detent mechanism 320 is in the second biasing state corresponding to the second position of the switching actuator 306, the pivot axis 328R of the link element 328 is located at a second side of the line L opposite to the first side. In the second biasing state, the second biasing force F2 applied by the spring 322 is located at the second side of the line L along a direction different from that of the first biasing force Fl. The second biasing force F2 can counteract a spring force of the braking spring 216, and assists in keeping the switching actuator 306 in the second position and the braking spring 216 in the release state.

[0072] In conjunction with FIGS. 1-12, FIGS. 13 and 14 are schematic views illustrating exemplary operation for expanding the window shade 100 provided with the actuating system 200 described previously. Referring to FIGS. 1-10, supposing that the movable rail 104 is initially held in position relative to the head rail 102. In this initial state, the switching actuator 306 is in the first position. Accordingly, the axle adapter 214 is decoupled from the spool 236 and coupled to the brake engaging part 218 via the clutching part 244, and the braking spring 216 is in the engaged state. The tightening action exerted by the braking spring 216 on the brake engaging part 218 can prevent rotation of the axle adapter 214 and the transmission axle 202 in a direction that would lower the movable rail 104. Moreover, the detent mechanism 320 is in the first biasing state and can apply the first biasing force Fl (as shown in FIG. 10) that assists in keeping the switching actuator 306 in the first position and the braking spring 216 in the engaged state. As long as the switching actuator 306 is in the first position, the braking spring 216 thus remains in the engaged state.

[0073] Referring to FIGS. 3-7 and 11-13, when the window shade 100 is to be expanded, a user can rotate the switching actuator 306 about its lengthwise axis Y in one direction XI from the first position to the second position, and then release the switching actuator 306 in the second position. As described previously, this rotational displacement of the switching actuator 306 from the first position to the second position can urge the spring coupler 308 to move for causing the braking spring 216 to switch to the release state and loosen the frictional contact with the brake engaging part 218. As a result, the transmission axle 202, the axle adapter 214, the brake engaging part 218, and the clutching part 244 in the engaged position can rotate concurrently relative to the braking spring 216 for lowering the movable rail 104 by gravity action. The spool 236 and the clutching part 246 can remain generally stationary while the axle adapter 214 and the transmission axle 202 continuously rotate for lowering the movable rail 104. Moreover, the rotational displacement of the switching actuator 306 from the first position to the second position switches the detent mechanism 320 from the first biasing state to the second biasing state, whereby the detent mechanism 320 can apply the second biasing force F2 (as shown in FIG. 12) that assists in keeping the switching actuator 306 in the second position and the braking spring 216 in the release state. The movable rail 104 thus can lower without the need for the user to apply extra effort for holding the switching actuator 306 in the second position. As long as the switching actuator 306 is in the second position, the braking spring 216 remains in the release state.

[0074] Referring to FIGS. 3-7 and 14, when the movable rail 104 moving downward reaches a desired position, the user can reversely rotate the switching actuator 306 about its lengthwise axis Y in a direction X2 so that the switching actuator 306 is switched from the second position to the first position. As a result, the braking spring 216 can recover the engaged state, and the movable rail 104 can be held in the desired position relative to the head rail 102. Moreover, the rotational displacement of the switching actuator 306 from the second position to the first position switches the detent mechanism 320 from the second biasing state to the first biasing state, whereby the detent mechanism 320 can apply the first biasing force Fl (as shown in FIG. 10) that assists in keeping the switching actuator 306 in the first position.

[0075] In conjunction with FIGS. 1-8, FIGS. 15 and 16 are schematic views illustrating exemplary operation for raising the movable rail 104 of the window shade 100 provided with the actuating system 200 described previously. Referring to FIGS. 3-8 and 15, when a user wants to raise the movable rail 104, the operating part 238 can be pulled downward with the handle 312, which causes the spool 236 to rotate in the unwinding direction. As a result, the clutching mechanism 222 is switched to the state in which the axle adapter 214 is decoupled from the brake engaging part 218 and coupled to the spool 236 via the clutching part 246 like previously described. Accordingly, the transmission axle 202, the axle adapter 214 and the spool 236 can rotate concurrently for raising the movable rail 104, while the braking spring 216 remains in the engaged state.

[0076] Referring to FIGS. 3-8 and 16, the user can release the handle 312 when the movable rail 104 has reached a desired position or when the operating part 238 has extended a maximum length. As a result, the spool 236 rotates for winding the operating part 238 owing to the action of the spring 240, and the clutching mechanism 222 is switched to the state in which the axle adapter 214 is decoupled from the spool 236 and coupled to the brake engaging part 218 via the clutching part 244 like previously described. Accordingly, the tightening action exerted by the braking spring 216 on the brake engaging part 218 can prevent rotation of the axle adapter 214 and the transmission axle 202 so that the movable rail 104 is held in position while the spool 236 rotates in the winding direction.

[0077] The aforementioned actuation and release of the operating part 238 can be repeated multiple times until the movable rail 104 rises to a desired position. The switching actuator 306 can remain in the first position during the aforementioned operation for raising the movable rail 104.

[0078] FIG. 17 is an exploded view illustrating a variant construction of the control module 206 in which the transmission assembly 310 previously described is replaced with a transmission assembly 310’, and FIG. 18 is an enlarged view illustrating some construction details of the transmission assembly 310’. Referring to FIGS. 17 and 18, the transmission assembly 310’ includes transmission elements that are configured to convert a sliding movement of the switching actuator 306 along a vertical direction into a rotation of the spring coupler 308 about the longitudinal axis 208 for causing the braking spring 216 to switch between the engaged state and the release state. Rather than rotating the switching actuator 306 about its lengthwise axis Y, the switching actuator 306 is configured to move up and down to switch between the first position and the second position.

[0079] Referring to FIGS. 17 and 18, the switching actuator 306 can be slidably connected to the housing 210 via a slider 340. For example, the slider 340 can be connected to an upper end of the switching actuator 306, and can be slidably received in a channel provided inside the housing 210. The switching actuator 306 and the slider 340 can slide in unison upward and downward relative to the housing 210.

[0080] The transmission assembly 310’ can include the transmission element 314 described previously, and replace the transmission element 316 shown in FIG. 3 with a transmission element 342 that is engaged with the gear portion 314A of the transmission element 314 and a toothed portion 344 provided on the slider 340. The transmission element 342 can be a gear element pivotally connected to the housing 210 about a pivot axis 342R that is parallel to and spaced apart from the pivot axis 314R of the transmission element 314. The toothed portion 344 may extend generally parallel to an axis of sliding movement of the slider 340. With this arrangement, the switching actuator 306 can slide downward from the first position to the second position, which can be transmitted through the transmission assembly 310’ and cause the spring coupler 308 to rotate and urge the braking spring 216 to switch from the engaged state to the release state. Conversely, an upward sliding displacement of the switching actuator 306 from the second position to the first position causes the spring coupler 308 to rotate reversely so that the braking spring 216 switches from the release state to the engaged state.

[0081] Aside the transmission assembly 310’, the remaining components of the control module 206 shown in FIG. 17 can be similar in construction and operation to the previous embodiment shown in FIG. 3.

[0082] In conjunction with FIGS. 17 and 18, FIGS. 19 and 20 are schematic views illustrating exemplary operation for expanding the window shade 100 provided with the control module 206 shown in FIG. 17. Referring to FIGS. 17-19, when the window shade 100 is to be expanded, a user can pull the switching actuator 306 downward in a direction VI from the first position to the second position, and then release the switching actuator 306 in the second position. This downward sliding displacement of the switching actuator 306 can urge the spring coupler 308 to move for causing the braking spring 216 to switch to the release state and loosen the frictional contact with the brake engaging part 218. As a result, the transmission axle 202, the axle adapter 214, the brake engaging part 218, and the clutching part 244 coupled thereto can rotate concurrently for lowering the movable rail 104 by gravity action. Moreover, the downward sliding displacement of the switching actuator 306 from the first position to the second position switches the detent mechanism 320 from the first biasing state to the second biasing state, whereby the detent mechanism 320 can apply the second biasing force F2 (as shown in FIG. 12) that assists in keeping the switching actuator 306 in the second position. Like previously described, the movable rail 104 can lower without the need for the user to apply extra effort for holding the switching actuator 306 in the second position.

[0083] Referring to FIG. 20, when the movable rail 104 moving downward reaches a desired position, the user can urge the switching actuator 306 to slide upward in a direction V2 so that the switching actuator 306 is switched from the second position to the first position. As a result, the braking spring 216 can recover the engaged state, and the movable rail 104 can be held in the desired position relative to the head rail 102. Moreover, the upward sliding displacement of the switching actuator 306 from the second position to the first position switches the detent mechanism 320 from the second biasing state to the first biasing state, whereby the detent mechanism 320 can apply the first biasing force Fl (as shown in FIG. 10) that assists in keeping the switching actuator 306 in the first position.

[0084] For retracting the window shade 100 shown in FIGS. 19 and 20, the movable rail 104 can be raised by pulling and releasing the handle 312 like previously described.

[0085] Advantages of the structures described herein include the ability to provide an actuating system that is conveniently operable to lower and raise a movable rail of a window shade with reduced effort. Moreover, the actuating system is adaptable for use with different types of window shades, which can simplify the manufacture of window shades.

[0086] Realization of the structures have been described only in the context of particular embodiments. These embodiments are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Structures and functionality presented as discrete components in the exemplary configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of the claims that follow.