Roll screen

Abstract

To provide a roll screen that can further suppress vertical movement of a weight member when adjusting the amount of light entering through relative movement of front and rear double screens, even when switching between lifting and lowering operations.SOLUTION: A roll screen of the present invention comprises two winding shafts 4a, 4b and a rotation direction switching mechanism 30. In the rotation direction switching mechanism, during light control operations for adjusting an overlap between front and rear double screens 5a, 5b, when one winding shaft 4a winds one screen 5a, the other winding shaft 4b unwinds the other screen 5b, and when one winding shaft 4a unwinds one screen 5a, the other winding shaft 4b winds the other screen 5b, thereby enabling rotation directions of the two winding shafts 4a, 4b to be switched. The rotation direction switching mechanism 30 comprises a rotation direction switching type driven gear unit 20 that has a speed conversion transmission function using a two-stage planetary gear 24.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a roll screen that is suspended and supported with a plurality of screens overlapped, and particularly to a roll screen that can adjust the amount of sunlight entering a room by adjusting the way the screens overlap.

Background Art

[0002] Conventionally, a roll screen has been known that can adjust the amount of sunlight entering a room by relatively moving a screen overlapped in a double layer in the vertical direction.

[0003] In such a roll screen, a light-transmitting portion that partially transmits light and a light-shielding portion that blocks light are alternately formed in stripes on the screen, and the screen is suspended and supported in a state where it is overlapped in a double layer. Then, by relatively moving the front and rear screens in the vertical direction by the operation of the operating means and adjusting the overlapping state of the light-transmitting portion and the light-shielding portion, the amount of sunlight can be adjusted.

[0004] In particular, two screens are formed by attaching the lower ends of two fabrics, each having a light-transmitting portion and a light-shielding portion, to a weight member and overlapping them. The upper ends of the respective screens are wound around separate winding shafts, or wound back, so that the screens can be raised and lowered. A roll screen is disclosed (see, for example, Patent Document 1). In this case, the weight member is mainly configured to include a single weight bar that attaches the lower ends of the two fabrics and allows rotation, and a single bottom cover that houses the weight bar. In the roll screen disclosed in Patent Document 1, by operating an operation string, each winding shaft always rotates in the same direction synchronously, and the two screens are raised and lowered simultaneously. Also, when adjusting the amount of sunlight, after the raising and lowering operation of the screen, if the operation string is operated in the reverse direction, only one of the winding shafts rotates within a predetermined rotation angle, and the light-transmitting portion and the light-shielding portion move relative to each other in the vertical direction, so that the overlapping width of the light-shielding portion with respect to the light-transmitting portion can be adjusted to adjust the amount of sunlight. However, in the technique disclosed in Patent Document 1, there is a problem that the height of the weight member provided at the lower limit of the screen moves up and down during the dimming operation of adjusting the overlapping width of the light-shielding portion with respect to the light-transmitting portion to adjust the amount of sunlight. When such up and down movement of the height of the weight member occurs, problems such as light leakage from the lower end portion of the weight member and impairment of airtightness occur.

[0005] To improve this problem, a technique is disclosed that suppresses the up and down movement of the height of the weight member by rotating the two winding shafts in reverse so that when one winding shaft winds one screen, the other winding shaft unwinds the other screen, or when one winding shaft unwinds one screen, the other winding shaft winds the other screen during the dimming operation (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the technique disclosed in Patent Document 1, when adjusting the amount of light collection by adjusting the overlapping width of the light-shielding part with respect to the light-transmitting part, there is a problem that the height of the weight member provided at the lower limit of the screen moves up and down. When such up and down movement of the height of the weight member occurs, problems such as light leakage from the lower end part of the weight member and deterioration of airtightness occur.

[0008] On the other hand, in the technique disclosed in Patent Document 2, during the dimming operation, by rotating two winding shafts in the reverse direction, the up and down movement of the height of the weight member can be suppressed.

[0009] However, in the embodiment disclosed in this Patent Document 2, in the relationship of the internal gear, sun gear, and planetary gear of the carrier used as a mechanism for rotating two winding shafts in the reverse direction, there is room for improvement in principle to minimize the up and down movement of the weight member. Therefore, from a principle point of view, a technique that enables the amount of up and down movement of the weight member to be substantially zero when each of the two winding shafts is rotated in the opposite direction to each other is desired. If the amount of up and down movement of the weight member can be made substantially zero, it is possible to further prevent light leakage from below in a manner that the amount of light collection can be adjusted, and to enhance airtightness in a manner that the amount of ventilation can be adjusted.

[0010] Therefore, an object of the present invention is to provide a roll screen that can more effectively suppress the up and down movement of the weight member when adjusting the amount of light collection by the relative movement of the front and rear double screens, and further when switching the lifting operation, in view of the above problems.

Means for Solving the Problems

[0011] The roller screen of the present invention is a roller screen that suspends front and rear double screens, and has two winding shafts. When adjusting the light by adjusting the overlapping degree of the front and rear double screens, when one winding shaft winds up one screen, the other winding shaft winds back the other screen, and when the one winding shaft winds back the one screen, the other winding shaft winds up the other screen, so that the rotation direction of the two winding shafts can be switched. The rotation direction switching mechanism is provided with a drive gear that rotates in synchronization with the rotation of the one winding shaft, and a rotation direction switching type driven gear unit for switching the rotation direction of the other winding shaft and causing it to rotate in conjunction based on the rotation of the drive gear during the light adjustment operation and the lifting operation. The rotation direction switching type driven gear unit has a speed conversion transmission function of converting the rotation speed transmitted from the drive gear and rotatingly transmitting it in the reverse rotation direction to the other winding shaft so that each rotation speed of the two winding shafts rotates at a substantially same speed also during the light adjustment operation as during the lifting operation in which each rotation speed of the two winding shafts rotates at the same speed.

[0012] Further, in the roller screen of the present invention, the rotation direction switching type driven gear unit, as the speed conversion transmission function, includes a carrier base having a first protrusion, an internal gear that rotates in conjunction based on the rotation of the drive gear for rotating the one winding shaft and rotates integrally with the carrier base, a sun gear that is connected to the other winding shaft so as to rotate the other winding shaft, a two-stage planetary gear having a second protrusion that engages and disengages with the first protrusion by a rotational action, a first tooth portion that meshes with an inner tooth portion formed in the internal gear, and a second tooth portion that meshes with the sun gear with fewer teeth than the first tooth portion, and is rotatably supported coaxially with the internal gear and the sun gear, and a braking member that applies a predetermined braking torque to the rotation of the carrier. By switching the engagement and disengagement between the first protrusion on the carrier base and the second protrusion on the carrier, the light adjustment operation and the lifting operation can be continuously switched.

[0013] In addition, in the roll screen of the present invention, when the number of teeth of the inner tooth portion formed on the internal gear is Na, the number of teeth of the sun gear is Nb, the number of teeth of the first tooth portion in the two-stage planetary gear is Nc, and the number of teeth of the second tooth portion in the two-stage planetary gear is Nd, it is set so as to satisfy 0.99 ≦ Na / Nb × Nc / Nd ≦ 1.01.

Advantages of the Invention

[0014] According to the present invention, when relatively moving the front and rear double screens, particularly when adjusting the amount of sunlight received due to the relative movement of the front and rear double screens, and further when switching the lifting operation, it is possible to further suppress the vertical movement of the weight member.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0016] Hereinafter, with reference to the drawings, a roll screen according to an embodiment of the present invention will be described. In the present specification, with respect to the front view of the roll screen shown in FIG. 1, the upper side and the lower side in the drawing are defined as the upward direction (or upper side) and the downward direction (or lower side) according to the hanging direction of the screen, respectively, and the left direction in the drawing is defined as the left side of the roll screen, and the right direction in the drawing is defined as the right side of the roll screen for explanation. Also, in the examples described below, with respect to the front view of the roll screen shown in FIG. 1, the visible side is defined as the front side (or indoor side), and the opposite side is defined as the rear side (or outdoor side).

[0017] (Configuration of the roll screen) First, a roll screen according to an embodiment of the present invention will be described with reference to the drawings. In the roll screen of an embodiment shown in FIGS. 1 and 2, support brackets 3 are attached to both ends of a frame 2 that is attached to an attachment surface such as a window frame via an attachment bracket 1, and two winding shafts 4a and 4b are rotatably supported by the support brackets 3.

[0018] The winding shafts 4a and 4b are supported by the support brackets 3 at a predetermined interval in the vertical direction and are supported in a slightly offset state in the front-rear direction.

[0019] The upper end of the first screen 5a on the outdoor side is attached to the winding shaft 4a, and the upper end of the second screen 5b on the indoor side is attached to the winding shaft 4b. The first and second screens 5a and 5b are respectively suspended so as to be overlapped close to the winding shafts 4a and 4b.

[0020] In the winding shafts 4a and 4b illustrated in FIG. 2, the first and second screens 5a and 5b are supported from the outdoor side thereof.

[0021] Inside the winding shafts 4a and 4b, a spring motor 41 that reduces the operating force when the first and second screens 5a and 5b are wound up, a brake unit 42 that applies a predetermined braking force to the rotational torque of each winding shaft 4a and 4b, and the like are accommodated.

[0022] And each lower end of the first and second screens 5a and 5b is attached to a weight bar 6 (see FIG. 2), and both longitudinal ends (left and right directions) of the weight bar 6 are rotatably supported by a bottom cover 7 with an upward opening. And the first and second screens 5a and 5b are guided upward from inside the bottom cover 7 through its opening. Such a weight bar 6 and bottom cover 7 are configured as a weight member. Therefore, this weight member does not simply fix each lower end of the first and second screens 5a and 5b to produce a weight effect, but when pulling out the lower end of the first screen 5a from the bottom cover 7 according to the lifting and lowering operation and dimming operation, the lower end of the second screen 5b is pulled into the bottom cover 7, and conversely, when pulling out the lower end of the second screen 5b from the bottom cover 7, the lower end of the first screen 5a is pulled into the bottom cover 7, so as to suspend and support the weight bar 6 and produce a weight effect.

[0023] The first and second screens 5a and 5b have a light-transmitting part 8 that transmits light and a light-shielding part 9 that shields light formed in a striped pattern at equal intervals in the vertical direction. And when the light-transmitting parts 8 of the first and second screens 5a and 5b overlap in the front-rear direction, outside light can be taken in from the light-transmitting part 8, and when the light-transmitting part 8 of the first screen 5a overlaps with the light-shielding part 9 of the second screen 5b and the light-shielding part 9 of the first screen 5a overlaps with the light-transmitting part 8 of the second screen 5b in the front-rear direction, outside light can be blocked.

[0024] In addition, the light-transmitting part 8 provided on the first and second screens 5a and 5b can be configured to have high air permeability, and the light-shielding part 9 can be configured to have low air permeability. Therefore, the air permeability can also be adjusted by adjusting the overlapping width of the light-shielding part 9 with respect to the light-transmitting part 8.

[0025] An operating device 10 is attached to the right support bracket 3 shown in FIG. 1, and an endless ball chain 11 hangs down from the operating device 10. The operating device 10 has a pulley 15 for hanging the ball chain 11. By operating the ball chain 11, the winding shafts 4a and 4b can be synchronously rotated in the same direction at the same speed, enabling a lifting and lowering operation to lift and lower the first and second screens 5a and 5b together.

[0026] The ball chain 11 is formed into an endless shape with the ends of the finite shape connected by a connector 12, and restricting members 13a and 13b for restricting the lifting and lowering ranges of the first and second screens 5a and 5b are attached.

[0027] When the first and second screens 5a and 5b are pulled up to the upper limit, the restricting member 13a abuts against the rear side of the case 14 of the operating device 10, preventing further operation of the ball chain 11 in the same direction. Also, when the first and second screens 5a and 5b are lowered to the lower limit, the restricting member 13b abuts against the front side of the case 14, preventing further operation of the ball chain 11 in the same direction.

[0028] The connector 12 is composed of a ball locking portion for locking the balls of the ball chain 11 and a connecting portion for connecting the ball locking portion. When pulled with a force greater than a preset tensile force, the ball locking portion becomes detached from the connecting portion.

[0029] Incidentally, in the roller screen of this embodiment, after lifting and lowering the first and second screens 5a and 5b, when the ball chain 11 is pulled in the reverse direction, the winding shafts 4a and 4b can be synchronously rotated in opposite directions at substantially the same speed within a predetermined rotation angle, enabling the first and second screens 5a and 5b to be relatively moved up and down in opposite directions to each other. This allows a dimming operation to adjust the overlapping degree of the light transmitting portion 8 and the light shielding portion 9 and adjust the amount of sunlight intake.

[0030] The lifting operation for rotating the take-up shafts 4a and 4b in the same direction and the switching to the dimming operation for rotating the take-up shafts 4a and 4b in opposite directions can be performed continuously. This is achieved by providing a rotation direction switching mechanism 30 for the rotation axes of the take-up shafts 4a and 4b, which will be described in detail later. That is, the rotation direction switching mechanism 30 rotates the take-up shafts 4a and 4b in the same direction synchronously during the lifting operation of the first and second screens 5a and 5b, and rotates the take-up shafts 4a and 4b in opposite directions synchronously during the dimming operation of the first and second screens 5a and 5b, enabling the continuous operation switching between the lifting operation and the dimming operation.

[0031] Therefore, in the roller screen of the present embodiment, during the lifting operation, the first and second screens 5a and 5b are both wound up or unwound by the same-direction rotation of both take-up shafts 4a and 4b, and during the dimming operation, the unwinding operation of one shaft is performed in response to the winding operation of the other shaft among the take-up shafts 4a and 4b (it may also be paraphrased as the winding operation of one shaft is performed in response to the unwinding operation of the other shaft), and the lifting operation and the dimming operation can be switched in a continuous operation.

[0032] (Rotation Direction Switching Mechanism) More specifically, with reference to FIGS. 3 to 7, the configuration of the rotation direction switching mechanism 30 will be described. FIG. 3 is a cross-sectional side view showing the schematic configuration of an operating device 10 including a rotation direction switching mechanism 30 according to an embodiment of the roller screen according to the present invention. FIGS. 4(a), (b), and (c) are perspective views schematically showing the configuration of a rotation direction switching mechanism 30 according to an embodiment of the present invention. FIG. 5 is an exploded perspective view showing the schematic configuration of an operating device 10 including a rotation direction switching mechanism 30 according to an embodiment of the roller screen according to the present invention as viewed from the indoor side. FIG. 6 is an exploded perspective view showing the schematic configuration of an operating device 10 including a rotation direction switching mechanism 30 according to an embodiment of the roller screen according to the present invention as viewed from the outdoor side. FIGS. 7(a) and (b) are cross-sectional side views simply showing the operation of the gears related to the reverse switching of a rotation direction switching mechanism 30 according to an embodiment of the present invention.

[0033] In the example of this embodiment, as shown in FIGS. 3 and 4, the rotation direction switching mechanism 30 is incorporated into the operating device 10 having the pulley 15 for mounting the ball chain 11. However, the rotation direction switching mechanism 30 may be provided separately from the operating device 10 having the pulley 15. For example, when the operating device 10 is provided on the right end side of the winding shafts 4a and 4b as shown in FIG. 1, the rotation direction switching mechanism 30 may be provided on the left end side of the winding shafts 4a and 4b.

[0034] First, in this embodiment, as shown in FIG. 1, a pulley 15 is rotatably supported in the case 14 of the operating device 10, and the ball chain 11 is mounted on the pulley 15. Then, the pulley 15 is rotated in the forward and reverse directions by operating the ball chain 11.

[0035] The rotation direction switching mechanism 30 in this embodiment includes a drive gear 16, a transmission gear 17, and a rotation direction switching type driven gear unit 20. However, the rotation direction switching mechanism 30 may be configured without the transmission gear 17 or may be configured with a plurality of them. For example, when changing the distance or position of the winding shafts 4a and 4b, or the hanging positions of the first and second screens 5a and 5b from the winding shafts 4a and 4b (both hanging from the outdoor side in this embodiment), the necessity, number, and position of the transmission gear 17 are set as appropriate.

[0036] In this embodiment, as shown in FIG. 3, the drive gear 16 is rotatably supported by the columnar shaft portion 141 in the case 14 of the operating device 10. The drive gear 16 rotates integrally with the pulley 15. The rotation direction switching type driven gear unit 20 is rotatably supported by the columnar shaft portion 143 in the case 14. Then, the transmission gear 17 is rotatably supported by the columnar shaft portion 142 in the case 14 and transmits the rotation of the drive gear 16 to the rotation direction switching type driven gear unit 20.

[0037] The central axis of the drive gear 16 is coaxial with the central axis of the take-up shaft 4b, and the drive gear 16 is positioned on the right end side of the take-up shaft 4b and is engaged therewith in a non-rotatable manner. Further, the central axis of the rotation-direction switching type driven gear unit 20 is coaxial with the central axis of the take-up shaft 4a, and a member (the sun gear 22 described later) that constitutes a part of the rotation-direction switching type driven gear unit 20 is positioned on the right end side of the take-up shaft 4a and is engaged therewith in a non-rotatable manner.

[0038] The number of teeth of the drive gear 16 and the rotation-direction switching type driven gear unit 20 is the same, and the tooth portions (tooth portion 211 of the internal gear 21) in the drive gear 16, the transmission gear 17, and the rotation-direction switching type driven gear unit 20 are respectively meshed to form a structure. Based on the operation of the ball chain 11, a rotational force is applied from the drive gear 16 that rotates to the rotation-direction switching type driven gear unit 20 via the transmission gear 17.

[0039] As shown in FIG. 4(b), the transmission gear 17 has a central axis hole 171, and the central axis hole 171 is rotatably supported by a columnar shaft portion 142 extending from the case 14 (see FIG. 5).

[0040] In this example, the drive gear 16 is integrally formed with the pulley 15 as shown in FIG. 4(c), has a central axis hole 161, and the central axis hole 161 is rotatably supported by a columnar shaft portion 141 extending from the case 14 (see FIG. 5). Incidentally, a pair of fan-shaped engagement recesses 162 are formed on the circumferential surface of the central axis hole 161, and the pair of engagement recesses 162 engage with a pair of engagement protrusions 43 formed on the right end side of the take-up shaft 4b (see FIG. 5). Thereby, the take-up shaft 4b is connected to the drive gear 16 in a non-rotatable manner and can rotate integrally with the pulley 15.

[0041] (Rotation-direction switching type driven gear unit) The rotation direction switching type driven gear unit 20 has a speed conversion transmission function that converts the rotational speed transmitted from the drive gear 16 that rotates in synchronization with the rotation of the winding shaft 4b rotated by the rotation operation of the pulley 15 so as to rotate the two winding shafts 4a and 4b at substantially the same speed even during the dimming operation, as compared to the lifting operation that rotates the rotational speeds of the two winding shafts 4a and 4b at the same speed, and transmits the rotation to the winding shaft 4a in reverse rotation. As this speed conversion transmission function, as shown in Fig. 4(a) (in Fig. 4(a), some members are shown in a simplified perspective view), the rotation direction switching type driven gear unit 20 is composed of an internal gear 21, a sun gear 22, a carrier 23, three two-stage planetary gears 24, a brake spring 25, a spring case 26, and a carrier base 27, and its details will be described with reference to Figs. 5 and 6.

[0042] Referring to Fig. 5, the rotation direction switching type driven gear unit 20 is disposed in the accommodating portion 144 of the case 14. And a cylindrical spring case 26 formed of a hard material (for example, a metal material or a hard resin material) is fixed to the inner wall of the braking holding portion 145 provided at the central portion within the accommodating portion 144 of the case 14, such that the shaft portion 143 of the case 14 is positioned on the axis center of the spring case 26. Here, two recesses 262 are formed in the cylindrical spring case 26 (see Fig. 6), and these two recesses 262 are engaged with respective convex portions (not shown) formed at corresponding positions on the inner wall of the braking holding portion 145 in the case 14, and are fitted to be non-rotatable relative to the case 14. The brake spring 25 is abutted against the inner wall 261 side of the spring case 26 and accommodated so as to generate a predetermined braking force.

[0043] 5 and 6, the carrier base 27 has a substantially disk-shaped base body 271, and in the center of the base body 271, a substantially semicircular central shaft hole 272 is provided, and in the present embodiment, a substantially semicylindrical piece-shaped protrusion 273 protrudes from the base body 271 toward the case 14 along the central shaft hole 272. The base body 271 also has a substantially semicircular central shaft hole 274 that is connected to the outer wall of the substantially semicylindrical piece-shaped protrusion 273 and opens with a larger diameter than the central shaft hole 272. The central shaft hole 272 and the central shaft hole 274 allow the columnar shaft portion 143 extending from the case 14 to pass through. In the present embodiment, the protrusion 273 is relatively wide in the rotation direction, so that the shaft portion 143 is stably supported for rotation. However, the predetermined rotation angle related to the dimming operation can be changed by changing the rotational width of the protrusion 273, and even if the protrusion 273 is relatively narrow in the rotational direction to increase the predetermined rotation angle, it can be stably supported by the shaft 143 by providing a sufficient length protruding from the base body 271. In addition, the base body 271 is provided with a slightly protruding annular step 277 surrounding the outer wall of the protrusion 273 and the central shaft hole 274, and this annular step 277 is fitted to the annular end of the spring case 26 so as to be relatively rotatable. For this reason, the outer wall of the approximately semi-cylindrical piece-shaped protrusion 273 of the carrier base 27 is positioned inside the brake spring 25 housed on the inner wall 261 side of the spring case 26. Also, the brake spring 25 is configured to be rotatably supported between the annular step 277 of the carrier base 27 and the inner wall of the brake retaining portion 145 of the case 14, stabilizing the braking action of the brake spring 25 abutting against the inner wall 261 side of the spring case 26. Therefore, the carrier base 27 is supported rotatably relative to the spring case 26 at its annular step 277, and is also fitted to the internal gear 21, which will be described in detail later, so as to rotate integrally therewith, so that the carrier base 27 is indirectly supported rotatably relative to the case 14. For this reason, even if the rotational width of the protrusion 273 is changed to be narrower, the carrier base 27 is stably supported rotatably relative to the case 14.

[0044] In this carrier base 27, convex portions 275 are provided at three rotationally symmetric positions on the periphery of the base body 271. The base body 271 is fitted into a circumferential recess 215 formed on the surface of the case 14 side of the internal gear 21, and the convex portions 275 provided on the base body 271 correspond to and engage with recesses 216 provided at three rotationally symmetric positions on the periphery of the circumferential recess 215. For this reason, the carrier base 27 always rotates in the same direction as the internal gear 21 rotates.

[0045] Further, on the side of the carrier base 27 opposite to the surface on which the protrusion 273 is formed, an annular convex portion 277 that slightly protrudes to rotatably support the flange of the disc portion 231 formed on the carrier 23 is formed.

[0046] The carrier 23 generally has an outer shape in which a substantially cylindrical cylindrical wall 234 is integrally formed on the disc portion 231, and the periphery of the disc portion 231 forms a flange with respect to the cylindrical wall 234. A central shaft hole 232 is provided at the center of the disc portion 231, and a columnar shaft portion 143 extending from the case 14 is passed through the central shaft hole 232 so that the carrier 23 is rotatably supported with respect to the case 14.

[0047] Further, in a part of the region along the central shaft hole 232 of the carrier 23, a substantially six-sector cylindrical sheet-like protrusion 233 as shown in the figure in this example protrudes from the disc portion 231 toward the case 14 side. This protrusion 233 is sandwiched between the bent end portions 25a and 25b of the brake spring 25 and is engaged and inserted into the region of the central shaft hole 274 of the carrier base 27 so as to be relatively rotatable. Since the brake spring 25 is accommodated in contact with the inner wall 261 side of the spring case 26 to generate a predetermined braking force, the brake spring 25 and the spring case 26 are configured as a braking member that applies a predetermined braking torque to the rotation of the carrier 23.

[0048] Here, although it will be described later with reference to FIG. 7, the protrusion 273 of the carrier base 27 is configured such that a state of engagement and a state of non-engagement with respect to the protrusion 233 of the carrier 23 occur in the rotational direction. For example, when the carrier base 27 rotates in the same direction as the rotation of the internal gear 21, the protrusion 273 of the carrier base 27 abuts against the protrusion 233 of the carrier 23 via the end portions 25a or 25b in the rotational direction of the brake spring 25 due to the rotation of the carrier base 27, thereby entering a state of engagement. On the other hand, when the carrier base 27 rotates in the same direction as the rotation of the internal gear 21, within a predetermined relative rotation angle between the carrier base 27 and the carrier 23, the protrusion 273 of the carrier base 27 does not abut against either of the both end portions 25a and 25b in the rotational direction of the brake spring 25, that is, a non-engagement state where the protrusion 273 of the carrier base 27 does not engage with the protrusion 233 of the carrier 23 is obtained. Although a specific description will be given later, in the relationship between the protrusion 273 of the carrier base 27 and the protrusion 233 of the carrier 23, the rotation operation of the pulley 15 in the state of engagement in the rotational direction enables the lifting and lowering operation of the weight member, and the rotation operation of the pulley 15 in the state of non-engagement in the rotational direction enables a dimming operation that suppresses the vertical movement of the weight member.

[0049] In addition, it is preferable to sandwich the protrusion 233 of the carrier 23 between the both end portions 25a and 25b of the brake spring 25 with a predetermined play. That is, when the protrusion 273 of the carrier base 27 and the protrusion 233 of the carrier 23 engage in the rotational direction, a force acts in a direction in which the distance between the both end portions 25a and 25b narrows. Thereby, a force can be applied in the direction of reducing the diameter of the brake spring 25, the predetermined braking force of the brake spring 25 against the spring case 26 can be relaxed, and the rotation operation in the state of engagement in the rotational direction can be performed smoothly.

[0050] In the cylindrical wall 234 of the carrier 23, three planetary gear support portions 235 for rotatably symmetrically arranging three two-stage planetary gears 24 are formed at three positions in this example. The planetary gear support portions 235 penetrate the cylindrical wall 234, and a pair of pin holes 236 are formed in each planetary gear support portion 235. By pivotally supporting the two-stage planetary gear 24 with a shaft pin (not shown) inserted into the shaft hole 243 of the two-stage planetary gear 24 with respect to the pair of pin holes 236, each two-stage planetary gear 24 is pivotally supported rotatably by each planetary gear support portion 235.

[0051] Here, the two-stage planetary gear 24 has a first tooth portion 241 that meshes with the inner tooth portion 212 formed on the internal gear 21, and a second tooth portion 242 that meshes with the sun gear 22 with fewer teeth than the first tooth portion 241. And each two-stage planetary gear 24 rotatably supported by the cylindrical wall 234 of the carrier 23 is such that both the first and second tooth portions 241 and 242 slightly protrude inside and outside the cylindrical wall 234.

[0052] The sun gear 22 has a central shaft hole 221, and the central shaft hole 221 is rotatably supported by a columnar shaft portion 143 extending from the case 14. A pair of fan-shaped engaging recesses 222 are formed continuously on the circumferential surface of the central shaft hole 221, and the pair of engaging recesses 222 engage with a pair of engaging protrusions 44 formed on the right end side of the winding shaft 4a. Thereby, the winding shaft 4a is connected to the sun gear 22 so as not to be relatively rotatable and is integrally rotatable.

[0053] Further, the sun gear 22 is disposed inside the cylindrical wall 234 of the carrier 23 and is relatively rotatable with respect to the carrier 23. And the sun gear 22 has a shape in which a tooth portion 224 that meshes with the second tooth portion 242 of the two-stage planetary gear 24 and a circular portion 223 that extends in a cylindrical shape to avoid interference with the first tooth portion 241 of the two-stage planetary gear 24 are continuous.

[0054] The internal gear 21 has a substantially cylindrical outer shape in which a tooth portion 211 that meshes with the tooth portion of the transmission gear 17 and a cylindrical portion 214 formed in a cylindrical shape are continuous. Inside the substantially cylindrical outer shape, an inner tooth portion 212 that meshes with the first tooth portion 241 of the two-stage planetary gear 24 is formed. Further, the cylindrical portion 214 is rotatably supported with respect to a housing portion 144 having a substantially circular wall portion in the case 14. And the internal gear 21 houses the sun gear 22 and the carrier 23 that pivotally supports each two-stage planetary gear 24, and is placed so as to be covered with the carrier base 27. Specifically, a circumferential concave portion 215 is formed on the surface of the cylindrical portion 214 of the internal gear 21 on the side of the case 14, and the base body 271 of the carrier base 27 is fitted into this circumferential concave portion 215, and convex portions 275 provided on the base body 271 correspond to and engage with recesses 216 provided at three rotationally symmetric positions on the periphery of the circumferential concave portion 215. For this reason, the carrier base 27 always rotates in the same direction as the internal gear 21 rotates. In the example of the present embodiment, the rotational direction width of the recess 216 is set to be larger with a margin than the rotational direction width of the convex portion 275 (see FIG. 7(b)), thereby improving the assemblability when fitting the base body 271 of the carrier base 27 to the internal gear 21.

[0055] Then, the internal gear 21 is supported so as to be relatively rotatable individually with respect to both the sun gear 22 and the carrier 23 by the inner tooth portion 212 formed on the internal gear 21 meshing with the first tooth portion 241 of each two-stage planetary gear 24 that slightly projects outward from the carrier 23.

[0056] And the rotation direction switching type driven gear unit 20 is arranged such that the tooth portion 211 of the internal gear 21 meshes with the tooth portion of the transmission gear 17 with respect to the case 14 in which the tooth portion of the transmission gear 17 is housed by meshing with the tooth portion of the drive gear 16. For this reason, the internal gear 21 rotates in conjunction based on the rotation of the drive gear 16.

[0057] Thus, the rotation direction switching mechanism 30 of the present embodiment is configured to include a drive gear 16, a transmission gear 17, and a rotation direction switching type driven gear unit 20. The rotation of the pulley 15 is transmitted to the tooth portion 211 of the internal gear 21 in the rotation direction switching type driven gear unit 20 via the drive gear 16 and the transmission gear 17.

[0058] In the rotation direction switching type driven gear unit 20, a predetermined braking torque is generated on the carrier 23 with respect to the case 14 by the action of the braking members (brake spring 25 and spring case 26).

[0059] Therefore, when the carrier base 27 rotates forward and backward as the internal gear 21 rotates forward and backward, when the protrusion 273 of the carrier base 27 maintains a non-engaged state in the rotation direction with respect to the protrusion 233 of the carrier 23, even if the internal gear 21 rotates, the carrier 23 is in a fixed state where it is braked and held without rotating within the braking range of the predetermined braking torque with respect to the case 14. In this case, the two-stage planetary gear 24 provided on the carrier 23 rotates and the sun gear 22 operates to rotate synchronously in the opposite direction with respect to the internal gear 21.

[0060] That is, when the internal gear 21 rotates while the protrusion 273 of the carrier base 27 maintains a non-engaged state in the rotational direction with respect to the protrusion 233 of the carrier 23 in the direction of the solid arrow A shown in FIGS. 7(a) and 7(b), the carrier 23 does not relatively rotate with respect to the case 14 within the braking range of the predetermined braking torque due to the action of the braking member (the brake spring 25 and the spring case 26), and the two-stage planetary gear 24 rotates so that the sun gear 22 synchronously rotates in the direction of the solid arrow B opposite to the internal gear 21. Further, the two-stage planetary gear 24 is configured such that the first tooth portion 241 meshes with the inner tooth portion 212 formed on the internal gear 21, and the second tooth portion 242 meshes with the sun gear 22 with fewer teeth than the first tooth portion 241, thereby reducing the rotational speed difference between the internal gear 21 and the sun gear 22 when they rotate in opposite directions. By adjusting these tooth numbers, the rotational speed difference can be substantially eliminated. As a result, the take-up shafts 4a and 4b rotate synchronously in opposite directions at substantially the same speed, enabling the first and second screens 5a and 5b to relatively move up and down in opposite directions. That is, a dimming operation is possible in which the overlapping state between the light-transmitting portion 8 and the light-shielding portion 9 is adjusted while suppressing the vertical movement of the weight member, thereby adjusting the amount of light received.

[0061] On the other hand, when the carrier base 27 rotates forward and backward as the internal gear 21 rotates forward and backward, when the protrusion 273 of the carrier base 27 maintains an engaged state in the rotational direction with respect to the protrusion 233 of the carrier 23, the internal gear 21 rotates such that the carrier 23 also rotates in the same direction at the same speed. The two-stage planetary gear 24 provided on the carrier 23 becomes non-rotating, and the sun gear 22 operates to synchronously rotate in the same direction at the same speed with respect to the internal gear 21.

[0062] That is, when the internal gear 21 rotates while maintaining the state in which the protrusion 273 of the carrier base 27 engages with the protrusion 233 of the carrier 23 in the rotational direction along the solid arrow A shown in FIGS. 7(a) and 7(b), the rotation of the two-stage planetary gear 24 is blocked, and the carrier 23 and the sun gear 22 operate integrally against the predetermined braking torque to synchronously rotate in the same direction as the internal gear 21 in the direction of the broken-line arrow A. Thereby, the take-up shafts 4a and 4b can be synchronously rotated in the same direction at the same speed, enabling a lifting operation to lift the first and second screens 5a and 5b together.

[0063] And the protrusion 273 of the carrier base 27 can be continuously changed from the state of engaging with the protrusion 233 of the carrier 23 in the rotational direction to a disengaged state, or from a disengaged state to an engaged state. For this reason, the rotation direction switching mechanism 30 of the present embodiment can not only continuously switch from the lifting operation to the dimming operation by switching the forward and reverse rotations of the pulley 15, but also when the pulley 15 continuously rotates in the forward or reverse direction after switching the forward and reverse rotations, the rotation of the sun gear 22 can be switched between forward and reverse without stopping with respect to the rotation of the internal gear 21 (always rotating), thereby enabling continuous switching from the dimming operation to the lifting operation without causing an undesired slack in the first and second screens 5a and 5b.

[0064] Therefore, the rotation direction switching mechanism 30 of the present embodiment synchronously rotates the take-up shafts 4a and 4b in opposite directions to each other during the dimming operation, and synchronously rotates the take-up shafts 4a and 4b in the same direction to each other during the lifting operation, with respect to the rotation of the pulley 15 related to the dimming operation and the lifting operation. When continuously shifting from the dimming operation to the lifting operation and from the lifting operation to the dimming operation, the rotation directions of the take-up shafts 4a and 4b can be continuously switched without stopping the rotation of the take-up shafts 4a and 4b.

[0065] As can be understood from FIG. 7(b), since a predetermined rotation angle D at which the protrusion 273 of the carrier base 27 is disengaged from the protrusion 233 of the carrier 23 in the rotation direction is within the range of the dimming operation, the predetermined rotation angle D can be changed by adjusting the widths of the protrusion 233 and the protrusion 273.

[0066] Here, referring to FIG. 8, the point that the rotation direction switching mechanism 30 of the present embodiment enables dimming operation while suppressing the vertical movement of the weight members (the weight bar 6 and the bottom cover 7) more than the prior art will be described. First, as shown in FIG. 8(a), the lower ends of the first screen 5a hanging from the winding shaft 4a and the second screen 5b hanging from the winding shaft 4b are attached to the weight bar 6, and both ends in the longitudinal direction (left - right direction) of the weight bar 6 are rotatably supported by a bottom cover 7 having an upward opening. It is assumed that the bottom cover 7 is at a height h (≧0) from the floor surface.

[0067] First, as shown in FIG. 8(a), when performing a dimming operation, in order to suppress the vertical movement of the weight member at a height h from the floor surface, it is preferable to rotate the winding shafts 4a and 4b in opposite directions to each other. This is because, for example, when the winding shafts 4a and 4b are not rotated in opposite directions to each other during the dimming operation as disclosed in Patent Document 1, for example, when the rotation of the winding shaft 4a is stopped and only the winding operation by the winding shaft 4b is performed for dimming, the height h from the floor surface moves upward by the amount of movement of the second screen 5b due to the winding operation by the winding shaft 4b. Also, when the winding shafts 4a and 4b are rotated in opposite directions to each other, it is preferable that the difference between the moving speed V1 of the first screen 5a depending on the rewinding speed of the winding shaft 4a and the moving speed V2 of the second screen 5b depending on the winding speed of the winding shaft 4b is small. This is because the height h from the floor surface moves vertically by the difference between the amount of movement due to the moving speed V1 and the amount of movement due to the moving speed V2.

[0068] Therefore, as shown in FIG. 8(b), in the rotation direction switching type driven gear unit 20 of the rotation direction switching mechanism 30 according to an embodiment of the present invention, when the number of teeth of the inner tooth portion 212 formed on the internal gear 21 is Na, the number of teeth of the sun gear 22 is Nb, the number of teeth of the first tooth portion 241 in the two-stage planetary gear 24 is Nc, and the number of teeth of the second tooth portion 242 in the two-stage planetary gear 24 is Nd, it is set to satisfy 0.99 ≦ Na / Nb × Nc / Nd ≦ 1.01. That is, based on the example shown in FIG. 8(a), with respect to the moving speed V2 of the second screen 5b depending on the winding speed of the winding shaft 4b, the moving speed V1 of the first screen 5a depending on the rewinding speed of the winding shaft 4a rotating in the reverse direction with respect to the winding shaft 4b is given by V1 = (Na / Nb × Nc / Nd) × V2. Therefore, the closer (Na / Nb × Nc / Nd) is to 1, the more preferable it is. For example, when 50 mm is set as the relative movement amount of the first and second screens 5a and 5b by the dimming operation, the difference between the movement amount 50 mm corresponding to the movement speed V2 and the movement amount 50 mm × 0.99 = 49.5 mm or 50 mm × 1.01 = 50.5 mm corresponding to the movement speed V1 is 0.5 mm. Since this 0.5 mm corresponds to the fluctuation amount of the height h from the floor surface, it is a fluctuation amount that can be sufficiently ignored, and the vertical movement of the weight member hardly occurs. Practically, if the vertical movement of the weight member is 1 mm or less, a sufficient effect can be obtained. In an example of the rotation direction switching mechanism 30 of the present embodiment, Na = 69, Nb = 50, Nc = 8, Nd = 11, and (Na / Nb × Nc / Nd) = 1.003636. When 50 mm is set as the relative movement amount of the first and second screens 5a and 5b by the dimming operation, the fluctuation amount of the height h is about 0.18 mm. Therefore, the vertical movement of the weight member can be suppressed to almost zero.

[0069] As a comparative example, Fig. 8(c) shows a configuration example of a rotation-direction switching type driven gear unit 20' in a rotation-direction switching mechanism disclosed in Patent Document 2. In this rotation-direction switching type driven gear unit 20', when the number of teeth of the inner tooth portion 212' formed on the internal gear is Na', the number of teeth of the sun gear 22' is Nb', and the number of teeth Nc'(=Nd') of the tooth portion in the planetary gear 24' are set as Na' = 70, Nb' = 46, Nc' = Nd' = 12, (Na' / Nb' × Nc' / Nd') = 1.521739. When the relative movement amount of the first and second screens 5a and 5b by the dimming operation is set to 50 mm, the variation amount of the height h is about 26 mm. Although it is an improvement over the technique of Patent Document 1, it can be seen that there is still room for improvement in suppressing the vertical movement of the weight member.

[0070] As described above, the rotation-direction switching type driven gear unit 20 has a speed conversion transmission function that converts the rotation speed transmitted from the drive gear 16 that rotates in synchronization with the rotation of the winding shaft 4b rotated by the rotation operation of the pulley 15 so that the rotation speeds of the two winding shafts 4a and 4b are substantially the same even during the dimming operation as during the lifting operation in which the rotation speeds of the two winding shafts 4a and 4b are rotated at the same speed, and rotates the winding shaft 4a in reverse rotation. As this speed conversion transmission function, the rotation-direction switching type driven gear unit 20 includes a carrier base 27 having a protrusion 273, an internal gear 21 that rotates in conjunction with the rotation of the drive gear 16 for rotating the winding shaft 4b and rotates the carrier base 27 integrally, a sun gear 22 connected to the winding shaft 4a so as to rotate the winding shaft 4a, a two-stage planetary gear 24 having a protrusion 233 that engages and disengages with the protrusion 273 by a rotational action, a first tooth portion 241 that meshes with the inner tooth portion 212 formed on the internal gear 21, and a second tooth portion 242 that meshes with the sun gear 22 with fewer teeth than the first tooth portion 241, and is rotatably supported, and a carrier 23 disposed coaxially rotatable with the internal gear 21 and the sun gear 22, and a braking member (brake spring 25 and spring case 26) that applies a predetermined braking torque to the rotation of the carrier 23.

[0071] (Overall operation of the roller screen) Here, the overall operation of the roller screen will be described with reference to FIGS. 9 to 12. Here, an example of continuously shifting from a lowering operation, through a dimming operation, to a raising operation will be described.

[0072] [During the lowering operation] First, as an explanation regarding the lowering operation for lowering the weight member, it will be described with reference to FIG. 9. FIG. 9 is an exploded perspective view showing the rotational state of the gears during the operation of the lowering operation with respect to the schematic configuration of the rotation direction switching mechanism 30 of the present embodiment. In order to lower the weight member, when the drive gear 16 integrally formed with the pulley 15 rotates in the direction of the arrow shown in FIG. 9 as the rewinding operation of the winding shaft 4b, the transmission gear 17 transmits the rotation of the drive gear 16 to the rotation direction switching type driven gear unit 20. The input in this rotation direction switching type driven gear unit 20 is the internal gear 21, and the output is the sun gear 22 connected to the winding shaft 4a. The internal gear 21 rotates in the same direction as the rotation of the drive gear 16 (the A direction shown in FIG. 7, and here it is denoted as CW corresponding to FIG. 2). As described above, along with the rotation of the internal gear 21, the carrier base 27 also rotates in the same direction. The protrusion 273 of the carrier base 27 is in a state of engaging with the protrusion 233 of the carrier 23 in the rotation direction, and since the carrier base 27 rotates while maintaining this state, the carrier 23 also rotates in the same direction. In this case, the rotation of the two-stage planetary gear 24 is blocked, and the sun gear 22 operates to rotate synchronously in the same direction with respect to the internal gear 21 integrally with the carrier 23 against the predetermined braking torque by the action of the braking member (brake spring 25 and spring case 26). For this reason, the rewinding operation of the winding shaft 4b and the rewinding operation of the winding shaft 4a are synchronized in the same direction at the same speed, and the weight member can be lowered.

[0073] And FIG. 11(a) schematically shows the operation during the lowering operation of the rotation direction switching mechanism 30 of an embodiment according to the present invention, and FIG. 12(a) schematically shows the operation during the lowering operation of the roller screen of the present embodiment.

[0074] During the downward operation of the first and second screens 5a and 5b shown in Fig. 11(a), the drive gear 16 rotates integrally with the rotation of the pulley 15 (see Fig. 4(c)), and the winding shaft 4b engaged with the drive gear 16 rotates in the rewinding direction of the second screen 5b (see Fig. 12(a)). The rotation of the drive gear 16 is transmitted to the internal gear 21 in the rotation direction switching type driven gear unit 20 via the transmission gear 17, and the internal gear 21 rotates in synchronization with and at the same speed as the drive gear 16 in the same direction.

[0075] At this time, in the rotation direction switching type driven gear unit 20, due to the action of the braking members (brake spring 25 and spring case 26), a predetermined braking torque is generated on the carrier 23 with respect to the case 14 (see Figs. 5 and 6). However, the protrusion 273 of the carrier base 27 maintains an engaged state with the protrusion 233 of the carrier 23 in the rotation direction. Since the carrier base 27 rotates, the carrier 23 also rotates in the same direction. In this case, the rotation of the two-stage planetary gear 24 is blocked, and against the predetermined braking torque, the carrier 23 and the sun gear 22 rotate synchronously in the same direction with respect to the internal gear 21.

[0076] Therefore, during the downward operation of the first and second screens 5a and 5b shown in Fig. 11(a), the sun gear 22 rotates in synchronization with and at the same speed as the drive gear 16 in the same direction, and the winding shaft 4a engaged with the sun gear 22 rotates in the rewinding direction of the first screen 5a (see Fig. 12(a)).

[0077] When the first and second screens 5a and 5b are lowered, as shown in Fig. 12(a), the light-transmitting portion 8 of the first screen 5a and the light-shielding portion 9 of the second screen 5b overlap in the front-rear direction, and the light-shielding portion 9 of the first screen 5a and the light-transmitting portion 8 of the second screen 5b overlap in the front-rear direction. While maintaining this state, as the first and second screens 5a and 5b are lowered, the weight members (weight bar 6 and bottom cover 7) are lowered to a lower limit position at a height h (≧0) from the floor surface, thereby enabling a shielding state.

[0078] 〔During dimming operation〕 First, as an explanation regarding the dimming operation of changing the overlapping state of the light-transmitting portion 8 and the light-shielding portion 9 in each of the first and second screens 5a and 5b to adjust the amount of sunlight received, reference will be made to FIG. 10 for explanation. FIG. 10 is an exploded perspective view showing the rotational state of gears when shifting from the lowering operation (lower limit position as an example) to the dimming operation regarding the schematic configuration of the rotation direction switching mechanism 30 of the present embodiment. In order to shift from the lowering operation (lower limit position as an example) to the dimming operation, when the drive gear 16 integrally formed with the pulley 15 rotates in the direction of the arrow shown in FIG. 10 as the operation of the winding shaft 4b (reverse rotation from the direction shown in FIG. 9), the transmission gear 17 transmits the rotation of the drive gear 16 to the rotation direction switching type driven gear unit 20. The input in this rotation direction switching type driven gear unit 20 is the internal gear 21, and the output is the sun gear 22 connected to the winding shaft 4a. The internal gear 21 rotates in the same direction as the rotation of the drive gear 16 (herein, denoted as CCW corresponding to FIG. 2). As described above, along with the rotation of the internal gear 21, the carrier base 27 also rotates in the same direction. Since the protrusion 273 of the carrier base 27 is in a state of non-engagement with respect to the protrusion 233 of the carrier 23 in the rotation direction, the carrier 23 does not rotate due to the action of the braking member (brake spring 25 and spring case 26). In this case, since the two-stage planetary gear 24 rotates, the sun gear 22 operates to rotate synchronously in the reverse direction (CW) with respect to the internal gear 21.

[0079] FIG. 11(b) schematically shows the operation during the dimming operation switched from the lowering operation of the rotation direction switching mechanism 30 according to an embodiment of the present invention, and FIG. 12(b) schematically shows the operation during the dimming operation switched from the lowering operation of the roll screen of the present embodiment. In particular, FIG. 12(b) schematically shows the operation during the dimming operation from the lower limit positions of the first and second screens 5a and 5b shown in FIG. 12(a).

[0080] During the dimming operation of the first and second screens 5a and 5b shown in Fig. 11(b), as a switching from the lowering operation shown in Fig. 11(a), a drive gear 16 that rotates in the reverse direction rotates integrally with the rotation of the pulley 15 (see Fig. 4(c)). A winding shaft 4b that engages with this drive gear 16 rotates in the winding direction of the second screen 5b (see Fig. 12(b)). The rotation of the drive gear 16 is transmitted to an internal gear 21 in a rotation-direction switching type of driven gear unit 20 via a transmission gear 17. The internal gear 21 rotates in synchronization with the drive gear 16 in the same direction and at the same speed.

[0081] At this time, in the rotation-direction switching type of driven gear unit 20, due to the action of a braking member (a brake spring 25 and a spring case 26), a predetermined braking torque is generated in the carrier 23 with respect to the case 14 (see Figs. 5 and 6). A protrusion 273 of the carrier base 27 becomes non-engaged with a protrusion 233 of the carrier 23 in the rotation direction. When the internal gear 21 rotates while maintaining this non-engaged state, the carrier 23 does not relatively rotate with respect to the case 14 within the braking range of the predetermined braking torque, and each two-stage planetary gear 24 rotates. The sun gear 22 rotates synchronously in the reverse direction with respect to the internal gear 21 via each two-stage planetary gear 24. In this case, as described with reference to Fig. 8, due to the configuration of the two-stage planetary gear 24, the sun gear 22 rotates synchronously in the reverse direction with respect to the internal gear 21 at substantially the same speed.

[0082] Therefore, during the dimming operation of the first and second screens 5a and 5b shown in Fig. 11(b), the sun gear 22 rotates synchronously in the reverse direction with respect to the drive gear 16 at substantially the same speed, and a winding shaft 4a that engages with this sun gear 22 rotates in the rewinding direction of the first screen 5a (see Fig. 12(b)).

[0083] In this way, since the first screen 5a is rewound according to the winding amount of the second screen 5b, the weight members (the weight bar 6 and the bottom cover 7) are suppressed from moving up and down to such an extent that the amount of variation is substantially 0. Then, the first and second screens 5a and 5b can be relatively moved up and down in opposite directions to each other, that is, a dimming operation is possible in which the overlapping state of the light-transmitting portion 8 and the light-shielding portion 9 can be adjusted to adjust the amount of sunlight.

[0084] In addition, as long as the protrusion 273 of the carrier base 27 is maintained in a non-engaged state with respect to the protrusion 233 of the carrier 23 in the rotational direction, even if the pulley 15 (that is, the drive gear 16) is rotated forward and backward, the weight members (the weight bar 6 and the bottom cover 7) hardly move up and down to such an extent that the amount of variation is substantially 0. Therefore, the usability of the dimming operation is improved.

[0085] Also, as described above, the lower end portions of the first and second screens 5a and 5b are attached to the weight bar 6, and both ends of the weight bar 6 are rotatably supported by a bottom cover 7 having an upward opening. The weight bar 6 and the bottom cover 7 are configured as weight members. These weight members do not simply fix the lower end portions of the first and second screens 5a and 5b to generate a weight action. When the lower end of the first screen 5a is pulled out from the bottom cover 7 in response to the lifting operation and the dimming operation, the lower end of the second screen 5b is pulled into the bottom cover 7. Conversely, when the lower end of the second screen 5b is pulled out from the bottom cover 7, the lower end of the first screen 5a is pulled into the bottom cover 7. In this way, the weight bar 6 is suspended and supported to generate a weight action.

[0086] The rotation amount related to the switching between engagement and non-engagement in the rotational direction between the protrusion 273 of the carrier base 27 related to the dimming operation and the protrusion 233 of the carrier 23, and the rotation amount (pull-in or pull-out amount) of the weight bar 6 correspond to one pitch of the light-transmitting portion 8 and the light-shielding portion 9 that are continuous at a predetermined interval in each of the first and second screens 5a and 5b. In this example, the vertical length of the light-shielding portion 9 is about twice the vertical length of the light-transmitting portion 8 to constitute one pitch.

[0087] [During the ascending operation] The operation during the ascending operation to raise the weight member is the reverse of the direction of the arrow shown in FIG. 9 showing the operation during the descending operation. Therefore, further illustration and description of the rotational state of the gears in the rotation direction switching mechanism 30 in that case are omitted.

[0088] FIG. 11(c) schematically shows the operation during the ascending operation continuously shifting from the dimming operation of the rotation direction switching mechanism 30 according to an embodiment of the present invention, and FIG. 12(c) schematically shows the operation during the ascending operation continuously shifting from the dimming operation of the roller screen of this embodiment.

[0089] First, during the ascending operation of the first and second screens 5a and 5b shown in FIG. 11(c), the drive gear 16 that rotates in the reverse direction to the descending operation shown in FIG. 11(a) rotates integrally with the rotation of the pulley 15 (see FIG. 4(c)), and the winding shaft 4b engaged with the drive gear 16 rotates in the winding direction of the second screen 5b (see FIG. 12(c)). The rotation of the drive gear 16 is transmitted to the internal gear 21 in the rotation direction switching type driven gear unit 20 via the transmission gear 17, and the internal gear 21 rotates in synchronization with the drive gear 16 in the same direction at the same speed.

[0090] At this time, in the rotation direction switching type driven gear unit 20, a predetermined braking torque is generated on the carrier 23 with respect to the case 14 by the action of the braking member (brake spring 25 and spring case 26) (see FIGS. 5 and 6), but the protrusion 273 of the carrier base 27 maintains an engaged state with the protrusion 233 of the carrier 23 in the rotation direction, and since the carrier base 27 rotates, the carrier 23 also rotates in the same direction. In this case, the rotation of the two-stage planetary gear 24 is blocked, and the carrier 23 and the sun gear 22 rotate synchronously in the same direction with respect to the internal gear 21 against the predetermined braking torque.

[0091] Therefore, during the ascending operation of the first and second screens 5a and 5b shown in FIG. 11(c), the sun gear 22 rotates synchronously and at the same speed as the drive gear 16 in the same direction, and the take-up shaft 4a engaged with the sun gear 22 rotates in the take-up direction of the first screen 5a (see FIG. 12(c)).

[0092] Then, the first and second screens 5a and 5b can be raised to a desired height to be in an open state.

[0093] As described above, the rotation amount related to the switching between the engagement and non-engagement in the rotation direction between the protrusion 273 of the carrier base 27 and the protrusion 233 of the carrier 23 related to the dimming operation, and the rotation amount (retraction or extraction amount) of the weight bar 6 correspond to one pitch of the light-transmitting part 8 and the light-shielding part 9 that are continuous at predetermined intervals on each of the first and second screens 5a and 5b. For this reason, when the take-up shafts 4a and 4b have the same diameter, referring to point A on the circumferential surface of the take-up shaft 4a shown in FIG. 12(a) and point B on the circumferential surface of the take-up shaft 4b, as shown in FIG. 12(b), for the take-up shaft 4a, the dimming operation rotates in the clockwise direction as shown, and in synchronization therewith, for the take-up shaft 4b, within the range of rotating in the counterclockwise direction as shown, the overlapping condition between the light-transmitting part 8 and the light-shielding part 9 can be adjusted. Also, in the ascending operation, as shown in FIG. 12(c), while maintaining the phase difference (rotation angle difference) between point A on the circumferential surface of the take-up shaft 4a and point B on the circumferential surface of the take-up shaft 4b, both the take-up shafts 4a and 4b rotate synchronously in the take-up direction of the first and second screens 5a and 5b. Therefore, during this ascending operation, without causing slack in the first and second screens 5a and 5b, each light-transmitting part 8 of the first and second screens 5a and 5b overlaps in the front-rear direction, and each light-shielding part 9 also overlaps in the front-rear direction, and the first and second screens 5a and 5b ascend.

[0094] Also, when shifting continuously from the dimming operation to the lowering operation, it operates in the same manner. Therefore, when performing the lowering operation, without causing slack in the first and second screens 5a and 5b, for example, up to the lower limit position of the weight members (weight bar 6 and bottom cover 7) shown in FIG. 12(a), the light-transmitting portion 8 of the first screen 5a and the light-blocking portion 9 of the second screen 5b overlap in the front-rear direction, and the light-blocking portion 9 of the first screen 5a and the light-transmitting portion 8 of the second screen 5b overlap in the front-rear direction, maintaining this state, the first and second screens 5a and 5b are lowered.

[0095] Thus, in this embodiment, after the first and second screens 5a and 5b are lifted and lowered together, when the ball chain 11 is operated in the reverse direction to rotate the drive gear 16 in the reverse direction, due to the action of the rotation direction switching mechanism 30, the winding shaft 4a is rotated in the opposite direction to the winding shaft 4b, enabling the dimming operation. Therefore, by the dimming operation in which this winding shaft 4a is rotated in the opposite direction to the winding shaft 4b, the first screen 5a is rewound according to the winding amount of the second screen 5b, or the first screen 5a is wound according to the rewinding amount of the second screen 5b. Due to the configuration of the two-stage planetary gear 24, the sun gear 22 rotates in synchronization with the internal gear 21 in the opposite direction at substantially the same speed. Therefore, it can be said that the vertical movement of the weight members (weight bar 6 and bottom cover 7) is suppressed to such an extent that the fluctuation amount is substantially 0.

[0096] Therefore, compared with the prior art, the roll screen of this embodiment can suppress the vertical movement of the weight members (weight bar 6 and bottom cover 7) more during the dimming operation and perform the operation of adjusting the amount of sunlight received.

[0097] And the operation during the dimming operation of the roll screen of this embodiment operates in the same manner regardless of whether the weight members (weight bar 6 and bottom cover 7) are at the lower limit position. Therefore, a roll screen having a dimming function or a ventilation adjustment function at an arbitrary position of the weight members (weight bar 6 and bottom cover 7) can be realized.

[0098] In particular, when the weight members (weight bar 6 and bottom cover 7) are in the lower limit position during the dimming operation, the roll screen of the present embodiment can prevent light leakage from below the weight members (weight bar 6 and bottom cover 7) in a manner that allows adjustment of the light intake amount, and can enhance the airtightness from below the weight members (weight bar 6 and bottom cover 7) in a manner that allows adjustment of the ventilation amount, as compared with the prior art.

[0099] In addition, the roll screen of the present embodiment contributes to the miniaturization of the weight bar 6 and the bottom cover 7 rather than a configuration that allows the bottom cover 7 to move relative to the weight bar 6.

[0100] Further, in the present embodiment, the vertical movement of the weight members (weight bar 6 and bottom cover 7) can be more suppressed with a configuration that brings the front and rear double first and second screens 5a, 5b closer or into close contact, and the adjustment operation of the light intake amount can be performed without causing slack in the first and second screens 5a, 5b, thus improving usability.

[0101] As described above, the present invention has been described by giving examples of specific embodiments. However, the present invention is not limited to the examples of the above-described embodiments, and various modifications are possible without departing from the technical idea thereof. For example, in the examples of the above-described embodiments, the operation by the ball chain has been described as an example for the rotation operation of the winding shafts 4a, 4b, but a rotation operation by a string-like operation cord may also be used.

[0102] Also, in the examples of the above-described embodiments, mainly an example in which the rotation direction switching mechanism 30 is incorporated into the operation device 10 has been described. However, the rotation direction switching mechanism 30 may be provided separately from the operation device 10 having the pulley 15. For example, when the operation device 10 is provided on the right end side of the winding shafts 4a, 4b as shown in FIG. 1, the rotation direction switching mechanism 30 may be provided on the left end side of the winding shafts 4a, 4b.

[0103] Also, in the example of the above-described embodiment, mainly, the rotation direction switching mechanism 30 has been described as an example including the drive gear 16, the transmission gear 17, and the rotation direction switching type driven gear unit 20. However, the rotation direction switching mechanism 30 may be configured without the transmission gear 17 or may be configured to include a plurality of them.

[0104] Also, in the example of the above-described embodiment, mainly, the example in which the brake spring 25 and the spring case 26 are used as the braking members to generate a predetermined braking torque in the carrier 23 has been described. However, any member may be used as long as it can generate a predetermined braking torque in the carrier 23. For example, a rubber material may be used.

[0105] Also, in the example of the above-described embodiment, mainly, the rotation direction switching mechanism 30 is configured such that, with respect to the rotation of the pulley 15 related to the dimming operation and the lifting operation, the winding shafts 4a and 4b are synchronously rotated in opposite directions during the dimming operation, the winding shafts 4a and 4b are synchronously rotated in the same direction during the lifting operation, and when continuously shifting from the dimming operation to the lifting operation and from the lifting operation to the dimming operation, the main function of continuously switching the rotation directions of the winding shafts 4a and 4b without stopping the rotation of the winding shafts 4a and 4b is provided to the rotation direction switching type driven gear unit 20 associated with the rotation of the winding shaft 4a. However, the present invention is not limited to this. For example, the gear that rotates the winding shaft 4a is configured as a simple spur gear driven gear, and the rotation direction switching type driven gear unit 20 has the same function with respect to the rotation of the winding shaft 4b to configure the rotation direction switching mechanism 30, or the rotation of the drive gear 16 that rotates integrally with the rotation of the winding shaft 4b is transmitted to a transmission gear that transmits the rotation to a simple spur gear driven gear for rotating the winding shaft 4a, and the driven gear unit 20 has the same function as the driven gear unit 20 to configure the rotation direction switching mechanism 30.

Industrial Applicability

[0106] According to the present invention, when adjusting the amount of sunlight entering through the relative movement of the front and rear double screens, and further when switching the lifting operation, it is possible to further suppress the vertical movement of the weight member. Therefore, the present invention is useful for applications of a roller screen having front and rear double screens.

Explanation of Symbols

[0107] 1 Mounting Bracket 2 Frame 3 Support Bracket 4a, 4b Take-up Shaft 5a First Screen 5b Second Screen 6 Weight Bar 7 Bottom Cover 8 Translucent Portion 9 Light-Shielding Portion 10 Operating Device 11 Ball Chain 14 Case of Operating Device 16 Driving Gear 17 Transmission Gear 20 Rotation Direction Switchable Driven Gear Unit 21 Internal Gear 22 Sun Gear 23 Carrier 24 Two-Stage Planetary Gear 25 Brake Spring 26 Spring Case 27 Carrier Base 30 Rotation Direction Switching Mechanism

Claims

1. A roller screen for suspending a front and rear double screen, comprising: two winding shafts; When adjusting the light by adjusting the overlapping degree of the front and rear double screens, when one winding shaft winds one screen, the other winding shaft rewinds the other screen, and when the one winding shaft rewinds the one screen, the other winding shaft winds the other screen, and a rotation direction switching mechanism for switching the rotation directions of the two winding shafts; The rotation direction switching mechanism includes a drive gear that rotates in synchronization with the rotation of the one winding shaft, and a rotation direction switching type driven gear unit for switching the rotation direction of the other winding shaft and causing it to rotate in conjunction based on the rotation of the drive gear during the light adjustment operation and the lifting and lowering operation. The rotation direction switching type driven gear unit has a speed conversion transmission function of converting the rotation speed transmitted from the drive gear and rotatingly transmitting it in the reverse rotation direction to the other winding shaft so that each rotation speed of the two winding shafts rotates at substantially the same speed also during the light adjustment operation as during the lifting and lowering operation in which each rotation speed of the two winding shafts rotates at the same speed. A roller screen characterized by this.

2. The rotation direction switching type driven gear unit, as the speed conversion transmission function, a carrier base having a first protrusion; an internal gear that rotates in conjunction based on the rotation of the drive gear for rotating the one winding shaft and rotates integrally with the carrier base; a sun gear connected to the other winding shaft so as to rotate the other winding shaft; A two-stage planetary gear having a second protrusion that engages and disengages with the first protrusion by a rotational action, a first tooth portion that meshes with an inner tooth portion formed on the internal gear, and a second tooth portion that meshes with the sun gear with fewer teeth than the first tooth portion is rotatably supported on a shaft, and a carrier that is arranged to be coaxial and rotatable with the internal gear and the sun gear; a braking member that applies a predetermined braking torque to the rotation of the carrier; configured to include The roller screen according to claim 1, characterized in that the switching between the light adjustment operation and the lifting and lowering operation can be continuously switched by switching the engagement and disengagement between the first protrusion on the carrier base and the second protrusion on the carrier.

3. In the roller screen of the present invention, when the number of teeth of the inner tooth portion formed on the internal gear is Na, the number of teeth of the sun gear is Nb, the number of teeth of the first tooth portion in the two-stage planetary gear is Nc, and the number of teeth of the second tooth portion in the two-stage planetary gear is Nd, it is set so as to satisfy 0.99 ≦ Na / Nb × Nc / Nd ≦ 1.

01. The roller screen according to claim 2, characterized in that.

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