Shielding device

Abstract

To improve operability when moving a shield.SOLUTION: A shielding device comprises a winding portion that raises and lowers a slat suspended from a head box, an operation cord that is operated to move the slat, and a driving force transmission portion 31 that transmits the rotational force from the operation cord to the winding portion. The driving force transmission portion 31 is provided with a plurality of transmission systems 35, 36, and 37 for transmitting the driving force to the winding portion by gears, and an output portion 38 for outputting the driving force from one of the transmission systems to the winding portion. The transmission systems include, at least, a first transmission system 35 that transmits the driving force to the winding portion at a first reduction gear ratio in the first period from the start of operation, and a second transmission system 36 that transmits the driving force to the winding portion at a second reduction gear ratio that is different from the first reduction gear ratio by continuously being switched from the first transmission system 35 in the second period following the first period.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a shielding device that moves a shielding material. [Background technology]

[0002] In horizontal blinds, a lifting cord hangs down from a head box, and a bottom rail hangs down from the lifting cord. When the operating cord is pulled, a winding cone in the head box rotates in one direction and the lifting cord is wound up on the winding cone. This causes the bottom rail to rise, with the slats stacked on top of it. When the winding cone in the head box rotates in the other direction, the lifting cord is pulled out and the bottom rail is lowered (see Patent Document 1).

[0003] When the bottom rail starts to rise from its lowest position, there are still few slats piled up on the bottom rail and the load is small. On the other hand, as the bottom rail approaches its upper limit position, the number of slats piled up on the bottom rail increases and the load increases.

[0004] In this type of horizontal blind, the drive force transmission unit, which transmits the drive force generated by operating the operating cord to the winding cone, has a reduction ratio set so that the output torque matches the maximum load during lifting, i.e., the maximum load when the bottom rail approaches the upper limit position. This reduces the operating force required for the drive force transmission unit, allowing the bottom rail and slats to be lifted smoothly. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-143312 A Summary of the Invention [Problem to be solved by the invention]

[0006] When starting to raise the bottom rail at its lowest position, the load is small, so although it would be possible to select a reduction ratio that would reduce the output torque and increase the ascent speed, the ascent speed is set to a reduction ratio with a large output torque that matches the maximum load during ascent. For this reason, when starting to raise the bottom rail at its lowest position, the operator may feel that the ascent speed of the bottom rail is slow.

[0007] In addition to horizontal blinds, there are also pleated screens and vertical blinds as shading devices. Even with these shading devices, the load increases when the amount of shading material that moves increases when the shading material is opened. For this reason, the reduction ratio of the driving force transmission mechanism is set to match the maximum load, and the same problem occurs as with horizontal blinds. [Means for solving the problem]

[0008] The shielding device for solving the above problem includes a moving unit that moves a shielding material suspended from a head box, an operating unit that is operated to move the shielding material, and a driving force transmission unit that transmits a driving force from the operating unit to the moving unit, the driving force transmission unit including a plurality of transmission systems that transmit the driving force to the moving unit by gears, and an output unit that outputs the driving force from any one of the transmission systems to the moving unit, and the plurality of transmission systems are arranged to transmit the driving force from the moving unit to the driving unit at least from the start of operation. First Section a first transmission system that transmits the driving force to the moving part at a first reduction ratio; First Section Second to Second Section and a second transmission system that is continuously switched from the first transmission system to transmit the driving force to the moving part at a second reduction ratio different from the first reduction ratio.

[0009] In the above shielding device, the operating unit can be operated to move the shielding material in a first direction and a second direction opposite to the first direction, and the driving force transmission unit transmits the driving force to the moving unit through the first transmission system when moving the shielding material in the first direction, and then continuously transmits the driving force to the moving unit through the second transmission system. 。

[0010] In the above shading device, when the shielding material is moved in the second direction, the driving force transmission unit transmits the driving force to the moving unit through the first transmission system. 。 The above-mentioned shielding device may be configured to include a switching unit that enables the driving force to be transmitted to the first transmission system and the second transmission system when the shielding material is moved in the first direction, and enables the driving force to be transmitted to the first transmission system when the shielding material is moved in the second direction.

[0011] In the above shielding device, the first transmission system may include a first switching clutch that disconnects the first transmission system when a first load is applied, and the second transmission system may include a second switching clutch that disconnects the second transmission system when a second load different from the first load is applied, and a one-way clutch that rotates freely with respect to the output section when the first direction operation is being performed and the first switching clutch connects the first transmission system.

[0012] In the above shading device, the first direction is, for example, an ascending direction of the shielding material, the second direction is a descending direction of the shielding material, and the first reduction ratio is smaller than the second reduction ratio. Effect of the Invention

[0013] According to the present invention, it is possible to improve operability when moving the shielding material. [Brief description of the drawings]

[0014] [Figure 1] Front view of horizontal blinds. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a perspective view of the internal structure of the driving force transmission unit as viewed from the input side. [Figure 4] FIG. 4 is an exploded perspective view of the driving force transmission unit as viewed from the input side. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] 1A and 1B are diagrams showing the operation of the clutch drum, in which (a) shows the state when the bottom rail and slats are being raised, (b) shows the state when the operation is reversed from (a), and (c) shows the state when the bottom rail and slats are being lowered. [Figure 8] 13A and 13B are diagrams showing the operation of the clutch drum, in which (a) shows the state when the bottom rail and slats are being lowered, (b) shows the state when the state is reversed from (a), and (c) shows the state when the bottom rail and slats are being raised. [Figure 9] FIG. 11 is a cross-sectional view of the input portion and the switching portion, showing a state when the bottom rail and the slat are lowered. [Figure 10] FIG. 11 is a cross-sectional view of the input portion and the switching portion, showing the state when the bottom rail and the slat are raised. [Figure 11] FIG. [Figure 12] FIG. 4 is an exploded perspective view of the switching clutch as viewed from one side. [Figure 13] FIG. 4 is an exploded perspective view of the switching clutch as viewed from the other side. [Figure 14] FIG. 4 is a cross-sectional view at the position of an operating piece of the switching clutch. [Figure 15] 4 is a diagram showing the relationship between the first to third transmission gears and the first to third output gears when the first transmission system transmits rotation to an output section. FIG. [Figure 16] 4 is a perspective view of the driving force transmission portion when the first transmission system is transmitting rotation to the output portion. FIG. [Figure 17] 5 is a diagram showing the relationship between the first to third transmission gears and the first to third output gears when the second transmission system transmits rotation to an output portion. FIG. [Figure 18] 13 is a perspective view of the driving force transmission portion when the second transmission system is transmitting rotation to the output portion. FIG. [Figure 19] 6 is a diagram showing the relationship between the first to third transmission gears and the first to third output gears when the third transmission system transmits rotation to an output portion. FIG. [Figure 20] 13 is a perspective view of the driving force transmission portion when the third transmission system is transmitting rotation to the output portion. FIG. [Figure 21] FIG. 13 is a diagram showing the relationship between the height of the bottom rail and the rotational speed of the winding section during ascent. [Figure 22] 13 is a diagram showing the relationship between the height of the bottom rail and the rotational speed of each switching clutch during ascent. FIG. [Figure 23] 13 is a diagram showing the relationship between the height of the bottom rail during lifting and the operating force pulling the operating cord downward. FIG. [Figure 24] 13 is a diagram showing the relationship between the height of the bottom rail and the rotation speed of the winding section during lowering and ascending. FIG. [Diagram 25] 13 is a diagram showing the relationship between the height of the bottom rail and the rotational speed of each switching clutch during a downward movement. FIG. [Figure 26] 13 is a diagram showing the relationship between the height of the bottom rail and the operating force pulling the operating cord downward when the bottom rail is lowered. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a horizontal blind to which the present invention is applied will be described with reference to the drawings. [Overall configuration] As shown in Fig. 1, a horizontal blind 10, which is an example of a shading device, includes a head box 11, a ladder cord 12, slats 13, a bottom rail 14, and a lifting cord 15. The head box 11 has a U-shape in a side view with an open top. The head box 11 is attached to a mounting portion such as a ceiling, a window frame, or a curtain box.

[0016] The ladder cord 12 hangs down from the head box 11. The ladder cord 12 includes a pair of warp threads and a weft thread that is suspended between the pair of warp threads. A plurality of weft threads are provided between the pair of warp threads along the lifting direction, which is the height direction of the horizontal blind 10. Each row of weft threads provided between the pair of warp threads along the lifting direction supports the slats 13.

[0017] The slats 13 are shielding materials for blocking out sunlight and the like. The slats 13 are elongated rectangular thin plates. The slats 13 are supported by weft threads arranged along the lifting direction between a pair of warp threads so that the tilt of the slats 13 can be adjusted. A bottom rail 14 is provided below the slat 13 located at the lowest level among the multiple slats 13.

[0018] The bottom rail 14 is a weight member for maintaining the multiple slats 13 in a lowered state. The bottom rail 14 has approximately the same longitudinal length and lateral width as the slats 13. The bottom rail 14 is connected to the lower ends of a pair of warp threads in the ladder cord 12. Note that, although FIG. 1 illustrates a configuration in which two ladder cords 12 are provided, the number of ladder cords 12 is not limited, and it is sufficient to provide the number necessary to support the slats 13.

[0019] The lifting / lowering cord 15 hangs down from the head box 11 near the ladder cord 12. The lifting / lowering cord 15 is inserted into an insertion hole (not shown) provided in the center of the short side of each slat 13, and the lower end is connected to the bottom rail 14. When the lifting / lowering cord 15 is pulled up, the bottom rail 14 is pulled up, and the multiple slats 13 rise so as to be stacked on the bottom rail 14. Note that while FIG. 1 shows a configuration in which one lifting / lowering cord 15 is provided, the number of lifting / lowering cords 15 is not limited, and it is sufficient to provide the number necessary to raise and lower the slats 13.

[0020] The head box 11 has therein a drive shaft 20, an operation unit 21, a cord support unit 22, and a tilt section 27. The drive shaft 20 is a square shaft extending in the longitudinal direction of the head box 11. The drive shaft 20 is connected to a drive force transmission section 31, the cord support unit 22, and the tilt section 27, and transmits a rotational force, which is a drive force applied from the operation unit 21, to each section.

[0021] The operation unit 21 is a part that constitutes the operation section, and is located at one end inside the head box 11. The operation unit 21 is connected to a driving force transmission unit 31. The operation unit 21 includes a circular operation cord 21a such as a ball chain, and a pulley around which the operation cord 21a is wound. The operation cord 21a is led outward from the head box 11. The operation unit 21 rotates the drive shaft 20 by continuously operating the operation cord 21a. Specifically, when the hanging portion on the near side as viewed from an operator positioned in front of the horizontal blind 10 is pulled downward, the operation cord 21a raises the bottom rail 14, and when the hanging portion on the far side is pulled downward, the bottom rail 14 is lowered.

[0022] The cord support unit 22 is connected to the drive shaft 20 and includes a tilt section 23, a winding section 24, an obstacle detection section 25, and a delay unit 26. Tilt portion 23 is connected to drive shaft 20 so as not to rotate relative to it, and has a groove into which ladder cord 12 is engaged. Tilt portion 23 rotates in conjunction with drive shaft 20. As tilt portion 23 rotates, one warp thread of ladder cord 12 rises and the other warp thread descends, adjusting the angle of slat 13. Incidentally, tilt portion 27 has the same configuration as tilt portion 23, and is attached to head box 11 without being mounted on cord support unit 22.

[0023] The winding unit 24 has as its main component a winding cone around which the lifting / lowering cord is wound, and is connected to the drive shaft 20 via an obstacle detection unit 25 and a delay unit 26. The lifting / lowering cord 15 is wound around the outer periphery of the winding cone. The winding cone rotates in conjunction with the drive shaft 20 to unwind or wind up the lifting / lowering cord 15. In other words, the winding cone is a moving unit that moves the slat 13 in the lifting / lowering direction by unwinding or winding up the lifting / lowering cord 15.

[0024] The obstacle detection unit 25 is connected to the winding unit 24 and the delay unit 26. When no tension in the pull-out direction is applied to the lift-up cord 15, the obstacle detection unit 25 stops the rotation of the winding unit 24 supporting the lift-up cord 15. In addition, if the bottom rail 14 collides with an obstacle when the slats 13 are being lowered, the obstacle detection unit 25 stops the rotation of the winding unit 24, thereby stopping the descent of the slats 13 and the bottom rail 14.

[0025] The delay unit 26 is connected to the drive shaft 20 so as not to rotate relative to the drive shaft 20. The delay unit 26 is provided with a stopper that restricts the rotation of the drive shaft 20 to prevent the slats 13 and the bottom rail 14 from descending due to their own weight. In addition, the delay unit 26 rotates the winding section 24 in conjunction with the drive shaft 20 when the drive shaft 20 rotates an amount of rotation required for the tilt operation to adjust the angle of the slats 13 or more.

[0026] Specifically, when the drive shaft 20 rotates in a direction to wind up the lift-up cord 15, first, the tilt unit 23 raises the warp threads on the outdoor side of the ladder cord 12 and lowers the warp threads on the indoor side. This changes the slats 13 from a fully closed state in which the long side on the outdoor side is tilted downward to a fully closed state in which the long side on the indoor side is tilted downward. The winding unit 24 then winds up the lift-up cord 15. When unwinding the lift-up cord 15, the slats 13 are changed from a fully closed reverse state to a fully closed normal state, and then the winding unit 24 unwinds the lift-up cord 15. Regarding the rotation direction of the drive shaft 20, the upward direction in which the slats 13 are raised is the first direction, and the downward direction in which the slats 13 are lowered is the second direction.

[0027] [Drive force transmission section] As shown in Figs. 1 and 2, the driving force transmission section 31 is connected to the operation unit 21. In the horizontal blind 10 as described above, when the hanging part on the front side of the operation cord 21a is pulled downward, the bottom rail 14 and the slats 13 are raised. At this time, the more the bottom rail 14 rises, the more the slats 13 are piled up. Therefore, the load applied to the winding section 24 also increases with the rise of the bottom rail 14, and the load on the rotation in the upward direction also increases. Therefore, the driving force transmission section 31 has a configuration that switches the reduction ratio according to the degree of rise of the bottom rail 14, that is, the magnitude of the load on the rotation in the upward direction. That is, when the bottom rail 14 is close to the lower limit position, the reduction ratio is reduced to relatively increase the rising speed, and when the bottom rail 14 is close to the upper limit position, the reduction ratio is increased to increase the output torque and reduce the operating force.

[0028] 2 to 4, the driving force transmission unit 31 includes an input unit 33, a switching unit 34, a first transmission system 35, a second transmission system 36, a third transmission system 37, an output unit 38, and a brake 39 in a case 32. This allows the reduction ratio to be switched in three stages. The reduction ratios of the first transmission system 35, the second transmission system 36, and the third transmission system 37 increase in this order. The output unit 38 and the brake 39 are connected to the drive shaft 20.

[0029] [Input section] As shown in FIG. 4, the input unit 33 is connected to the operation unit 21. The switching unit 34 switches the transmission system connecting the input unit 33 and the output unit 38. The first transmission system 35 is a transmission system for the initial ( First Section ), and when the bottom rail 14 and the slats 13 are lowered, the second transmission system 36 transmits the rotational force from the input unit 33 to the output unit 38. Second Section) to transmit the rotational force from the input portion 33 to the output portion 38. The third transmission system 37 transmits the rotational force from the input portion 33 to the output portion 38 in the later period ( Section 3 ) transmits the rotational force from the input portion 33 to the output portion 38.

[0030] As shown in FIGS. 5 and 6, the input portion 33 includes a first input shaft 41, a delay plate 42, an input gear 43, and a second input shaft 44. The first input shaft 41 includes an input protrusion 41a, a flange 41b, and a connecting protrusion 41c. The input protrusion 41a has a polygonal shape such as a hexagonal column. The connecting portion of the operation unit 21 is connected to the input protrusion 41a so as not to rotate relative to the input protrusion 41a. A recess 41d is formed on the inside of the input protrusion 41a. The flange 41b is located at the base end of the input protrusion 41a, and the connecting protrusion 41c protrudes from the flange 41b on the opposite side to the input protrusion 41a. The connecting protrusion 41c is provided with a fitting recess 41e into which the second input shaft 44 is fitted. The fitting recess 41e is a rectangular recess. The corner formed by the base end of the connecting protrusion 41c and the flange 41b is provided with a pair of first engaging protrusions 41f sandwiching the connecting protrusion 41c.

[0031] The delay plate 42 is an annular member that is fitted onto the connecting protrusion 41c. The inner peripheral surface of the delay plate 42 is provided with an inner protrusion 42a that determines the relative rotation amount between the first input shaft 41 and the delay plate 42. A pair of inner protrusions 42a are provided facing each other on the inner peripheral surface of the delay plate 42. When the delay plate 42 is fitted onto the connecting protrusion 41c, the first engagement protrusion 41f is located between the pair of inner protrusions 42a. The first input shaft 41 and the delay plate 42 are capable of relative rotation until the first engagement protrusion 41f and the inner protrusion 42a are engaged with each other.

[0032] The input gear 43 includes a cylindrical portion 43a and a gear portion 43b. The input gear 43 includes a through hole 43c. The through hole 43c is located at the center of the gear portion 43b and at the center of the bottom surface of the cylindrical portion 43a. The cylindrical portion 43a is a circular recess, and the delay plate 42 is housed inside. The outer peripheral surface of the delay plate 42 includes an outer protrusion 42b that determines the relative rotation amount between the delay plate 42 and the input gear 43. The outer protrusions 42b are provided in pairs facing each other on the outer peripheral surface of the delay plate 42. The inner peripheral surface of the cylindrical portion 43a includes a second engagement protrusion 43d that determines the relative rotation amount between the delay plate 42 and the input gear 43. When the delay plate 42 is fitted to the cylindrical portion 43a, the outer protrusion 42b is located between the second engagement protrusions 43d. The delay plate 42 and the input gear 43 are capable of relative rotation until the outer projection 42b engages with the second engagement projection 43d. A first input gear 61 of the first transmission system 35, a second input gear 64 of the second transmission system 36, and a third input gear 67 of the third transmission system 37 are connected to the gear portion 43b.

[0033] The second input shaft 44 includes a fitting shaft portion 44a, a flange 44b, and a shaft portion 44c. The fitting shaft portion 44a is a shaft portion that is fitted into the fitting recess 41e of the first input shaft 41 and has a rectangular prism shape. The fitting shaft portion 44a is fitted into the fitting recess 41e and is further fixed by a fixing member 45 such as a washer and a screw. As a result, the first input shaft 41 and the second input shaft 44 are integrated and cannot rotate relative to each other. The flange 44b is located at the base end of the fitting shaft portion 44a, and the shaft portion 44c protrudes from the flange 44b on the opposite side to the fitting shaft portion 44a. The outer circumferential surface of the shaft portion 44c includes a guide groove 44e that extends parallel to the rotation axis.

[0034] The input unit 33 configured as above rotates the directly connected second input shaft 44 when the first input shaft 41 rotates. On the other hand, when the first input shaft 41 rotates, the input gear 43 does not rotate until both the first engaging protrusion 41f and the inner protrusion 42a and the outer protrusion 42b and the second engaging protrusion 43d are engaged, and starts to rotate after both are engaged. That is, the input gear 43 to which the first input gear 61 of the first transmission system 35, the second input gear 64 of the second transmission system 36, and the third input gear 67 of the third transmission system 37 are connected starts to rotate with a delay relative to the rotation of the first input shaft 41. During this delay time, the switching unit 34 operated by the second input shaft 44 can be reliably switched from a position to lower the bottom rail 14 and the slats 13 to a position to raise them. That is, as will be described in detail later, the second transmission gear 54 and the third transmission gear 55 are switched from a disconnected state to a connected state with respect to the transmission shaft 53. Then, it becomes possible to transmit the rotational force from the input gear 43 to the first transmission system 35, the second transmission system 36, and the third transmission system 37.

[0035] [Switching section] As shown in FIG. 4, the switching unit 34 includes a clutch drum 51, a first transmission gear 52, a transmission shaft 53, a second transmission gear 54, and a third transmission gear 55.

[0036] The clutch drum 51 is a cylindrical body into which the shaft portion 44c of the second input shaft 44 is inserted. The inner peripheral surface of the clutch drum 51 is provided with a guide protrusion 51a that engages with the guide groove 44e. As a result, the clutch drum 51 is movable in the direction in which the rotation axis extends, but is unable to rotate relative to the shaft portion 44c and rotates integrally with it.

[0037] As shown in FIG. 7(a) to (c), the outer peripheral surface of the clutch drum 51 is provided with a first cam groove 51b and a second cam groove 51c. The first cam groove 51b and the second cam groove 51c are continuous grooves that are continuous in the circumferential direction of the clutch drum 51 and meander at a predetermined period in the direction in which the rotation axis extends, and are parallel grooves that are substantially parallel to each other. Here, the first cam groove 51b and the second cam groove 51c are connected at a plurality of points. The first cam groove 51b and the second cam groove 51c extend in the circumferential direction of the outer peripheral surface of the clutch drum 51, and are displaced so as to pass through positions A, B, and C that are parallel to each other. That is, the first cam groove 51b is displaced between positions A and B. The second cam groove 51c is displaced between positions B and C. The first cam groove 51b and the second cam groove 51c have a common portion at position B.

[0038] A ball 56 is engaged with the first cam groove 51b and the second cam groove 51c. The ball 56 is, for example, a steel ball, and is supported by a ball receiver 56a fixed to the case 32. The ball receiver 56a has a support groove 56b that supports the ball 56. The support groove 56b is a linear groove that extends perpendicular to the circumferential direction in which the first cam groove 51b and the second cam groove 51c extend. The support groove 56b supports the ball 56 so that it can move between the first cam groove 51b and the second cam groove 51c. The ball 56 moves in the support groove 56b in accordance with the meandering of the first cam groove 51b and the second cam groove 51c.

[0039] As shown in FIG. 7(a), when the bottom rail 14 and the slat 13 are raised, the clutch drum 51 usually rotates in the upward direction. The ball 56 travels in the first cam groove 51b while moving in the support groove 56b according to the meandering of the first cam groove 51b passing through the A position and the B position. At this time, the clutch drum 51 is biased toward the output portion 38 side (left side in the figure) located on the opposite side to the input portion 33. As shown in FIG. 7(b), when the bottom rail 14 and the slat 13 are lowered, the clutch drum 51 rotates in the reverse direction (downward direction). The ball 56 moves toward the second cam groove 51c and travels in the support groove 56b according to the meandering of the second cam groove 51c. As shown in FIG. 7(c), the ball 56 travels in the second cam groove 51c. At this time, the clutch drum 51 is biased toward the input portion 33 side (right side in the figure). The bias of the clutch drum 51 from the output portion 38 side to the input portion 33 side is completed before the delay period generated by the input portion 33 and the delay periods generated by each of the transmission systems 35 to 37 described below have elapsed.

[0040] As shown in FIG. 8(a), when the bottom rail 14 and the slat 13 are lowered, the clutch drum 51 usually rotates in the downward direction. The ball 56 travels in the second cam groove 51c while moving in the support groove 56b according to the meandering of the second cam groove 51c passing through the B position and the C position. At this time, the clutch drum 51 is biased toward the input portion 33 side (right side in the figure). As shown in FIG. 8(b), when the bottom rail 14 and the slat 13 are raised, the clutch drum 51 rotates in the reverse direction (upward direction). The ball 56 moves toward the first cam groove 51b and moves in the support groove 56b according to the meandering of the first cam groove 51b. As shown in FIG. 8(c), the ball 56 travels in the first cam groove 51b. At this time, the clutch drum 51 is biased toward the output portion 38 side (left side in the figure). The bias of the clutch drum 51 from the input portion 33 side to the output portion 38 side is completed before the delay period generated by the input portion 33 and the delay periods generated by each of the transmission systems 35 to 37 described below have elapsed.

[0041] 4, the first transmission gear 52 is disposed adjacent to the end of the clutch drum 51 on the opposite side to the input portion 33. The first transmission gear 52 has a first central opening 52a. The inner peripheral surface of the first central opening 52a has a guide groove 52b that engages with an input side guide ridge 53e of the transmission shaft 53. The input side guide ridge 53e engages with the guide groove 52b, so that the first transmission gear 52 is unable to rotate relative to the transmission shaft 53 and rotates integrally with it.

[0042] The transmission shaft 53 includes a first shaft support portion 53a, a second shaft support portion 53b, a third shaft support portion 53c, and a connection portion 53d. The first shaft support portion 53a is a portion that supports the first transmission gear 52, and includes an input side guide ridge 53e along the direction in which the rotation axis extends. The first transmission gear 52 has the first shaft support portion 53a inserted into the first central opening 52a, and the input side guide ridge 53e engaged with the guide groove 52b. As a result, the first transmission gear 52 is movable along the first shaft support portion 53a in the direction in which the rotation axis extends, but is not rotatable relative to the transmission shaft 53, and can rotate integrally with the transmission shaft 53.

[0043] The tip of the first shaft support portion 53a is provided with an annular groove 53h. The edge of a central through hole of a partition plate provided inside the clutch drum 51 engages with the annular groove 53h. As a result, the transmission shaft 53 is prevented from coming off the clutch drum 51 and is rotatable relative to the clutch drum 51. The transmission shaft 53 moves integrally with the clutch drum 51 in the direction in which the rotation axis extends.

[0044] The second shaft support portion 53b is a portion that supports the second transmission gear 54, and is provided with a locking claw 53f formed on a flange at the boundary with the first shaft support portion 53a. A plurality of locking claws 53f are provided in the circumferential direction, and the tip of each locking claw 53f is an inclined end inclined in one direction. The second transmission gear 54 is provided with a second central opening 54a. The inner peripheral surface of the second central opening 54a is provided with engagement recesses 54b to which the locking claws 53f are engaged. The same number of engagement recesses 54b are provided in the circumferential direction as the locking claws 53f. The tip of the partition portion that forms the boundary between adjacent engagement recesses 54b is configured with an inclined end that is inclined parallel to the inclination of the locking claws 53f so that it can move smoothly into the engagement recesses 54b when it abuts against the locking claws 53f. When the locking claw 53f is disengaged from the engagement recess 54b, the second transmission gear 54 is in a free-wheeling state and can rotate relative to the second shaft support portion 53b, and when the locking claw 53f is engaged with the engagement recess 54b, the second transmission gear 54 is in a non-rotatable state and can rotate integrally with the second shaft support portion 53b. When the inclined end of the locking claw 53f abuts against the inclined end of the partition portion, the second transmission gear 54 rotates slightly and shifts, and the locking claw 53f engages with the engagement recess 54b. The slight rotation of the second transmission gear 54 at this time is absorbed by the one-way clutch of the second output gear 66 connected to the second transmission gear 54.

[0045] The third shaft support portion 53c is a portion that supports the third transmission gear 55, and includes a locking claw 53g formed on a flange at the boundary with the second shaft support portion 53b. A plurality of locking claws 53g are provided in the circumferential direction, and the tip of each locking claw 53g is an inclined end inclined in one direction. The third transmission gear 55 includes a third central opening 55a. The inner peripheral surface of the third central opening 55a includes engagement recesses 55b with which the locking claws 53g are engaged. The number of engagement recesses 55b is the same as that of the locking claws 53g in the circumferential direction. The tip of the partition portion that forms the boundary between adjacent engagement recesses 55b is configured with an inclined end that is inclined parallel to the inclination of the locking claws 53g so that it can move smoothly into the engagement recesses 55b when it comes into contact with the locking claws 53g. The third transmission gear 55 is rotatable relative to the third shaft support portion 53c when the locking claw 53g is disengaged from the engagement recess 55b, and is non-rotatable relative to the third shaft support portion 53c when the locking claw 53g is engaged with the engagement recess 55b. When the inclined end of the locking claw 53g abuts against the inclined end of the partition portion, the third transmission gear 55 rotates slightly and shifts, and the locking claw 53g engages with the engagement recess 55b. The slight rotation of the third transmission gear 55 at this time is absorbed by the one-way clutch of the third output gear 69 connected to the third transmission gear 55.

[0046] The connection portion 53d is a portion that supports the output gear 81 that constitutes the output portion 38, and is provided with an output-side guide ridge 53i that extends in the direction in which the rotation axis line extends. When the bottom rail 14 and the slat 13 are lowered, the ball 56 is located in the second cam groove 51c (see FIG. 8(a)). Therefore, as shown in FIG. 9, the clutch drum 51 and the transmission shaft 53 are biased toward the input portion 33, the locking claws 53f and 53g are disengaged from the engagement recesses 55b and 54b, and the second transmission gear 54 and the third transmission gear 55 are separated from the transmission shaft 53 and are in an idling state.

[0047] When the bottom rail 14 and the slat 13 are raised, the ball 56 is located in the first cam groove 51b (see FIG. 7(a)). Therefore, the clutch drum 51 and the transmission shaft 53 are biased toward the output portion 38 as shown in FIG. 10, and the locking claws 53f and 53g engage with the engagement recesses 55b and 54b, so that the second transmission gear 54 and the third transmission gear 55 can rotate integrally with the transmission shaft 53.

[0048] [First transmission system] 4, the first transmission system 35 is a mechanism that connects the input part 33 and the output part 38 at the beginning of the upward movement of the bottom rail 14 and the slats 13 and at the downward movement of the bottom rail 14 and the slats 13, and has a first reduction ratio. Among the three transmission systems 35, 36, and 37, the first transmission system 35 has the smallest output torque and outputs a rotational force to the output part 38 at the highest rotation speed.

[0049] Specifically, the first transmission system 35 includes a first input gear 61, a first switching clutch 62, and a first output gear 63. The first input gear 61 includes a first central opening 61a into which an input member 71 of the first switching clutch 62 is inserted. The inner peripheral surface of the first central opening 61a includes a first protrusion 61b for delaying the rotation of the first switching clutch 62 relative to the first input gear 61. A pair of the first protrusions 61b are provided at opposing positions. The first input gear 61 is always connected to the gear portion 43b of the input gear 43 constituting the input portion 33. The first switching clutch 62 starts to rotate after the first protrusion 61b hits a restricting protrusion 71c of the input member 71 of the first switching clutch 62. The first switching clutch 62 has a configuration substantially similar to that of the second switching clutch 65 and the third switching clutch 68, and will be described in detail later.

[0050] The first output gear 63 is connected to the output member 76 of the first switching clutch 62 so as to rotate integrally with but not rotate relative to the output member 76, and is connected to the first transmission gear 52 constituting the switching unit 34. That is, in the first transmission system 35, a rotational force input from the input unit 33 is input to the first input gear 61, and the rotational force is transmitted from the first output gear 63 to the first transmission gear 52 of the switching unit 34. Unlike the second transmission gear 54 and the third transmission gear 55 described later, the first output gear 63 does not include a one-way clutch.

[0051] [Second transmission system] The second transmission system 36 is a mechanism that connects the input part 33 and the output part 38 in the middle of the rise of the bottom rail 14 and the slats 13, and has a second reduction ratio that is greater than the first reduction ratio. The second transmission system 36 has the middle output torque and rotation speed among the three transmission systems 35, 36, and 37.

[0052] Specifically, the second transmission system 36 includes a second input gear 64, a second switching clutch 65, and a second output gear 66. The second input gear 64 includes a second central opening 64a into which an input member 71 of the second switching clutch 65 is inserted. The inner peripheral surface of the second central opening 64a includes a second protrusion 64b for delaying the rotation of the second switching clutch 65 relative to the second input gear 64. The second protrusion 64b is provided in a pair at opposing positions. The second input gear 64 is constantly connected to the gear portion 43b of the input gear 43 constituting the input portion 33. The second switching clutch 65 starts to rotate after the second protrusion 64b hits the restricting protrusion 71c of the input member 71 of the second switching clutch 65. The second switching clutch 65 has a configuration substantially similar to that of the first switching clutch 62 and the third switching clutch 68, and will be described in detail later.

[0053] The second output gear 66 is connected to the output member 76 of the second switching clutch 65 and is connected to the second transmission gear 54 constituting the switching unit 34. That is, in the second transmission system 36, the rotational force input from the input unit 33 is input to the second input gear 64, and the rotational force is transmitted from the second output gear 66 to the second transmission gear 54 of the switching unit 34. Here, the second output gear 66 is provided with a one-way clutch. The second output gear 66 transmits only the rotation in the direction that lifts the bottom rail 14 and the slats 13 to the second transmission gear 54, and the one-way clutch rotates idly during the reverse rotation. Specifically, when the first output gear 63 transmits the rotation to the first transmission gear 52 during the lifting of the bottom rail 14 and the slats 13, the second output gear 66 does not transmit the rotation to the second transmission gear 54 because the one-way clutch rotates idly.

[0054] [Third transmission system] The third transmission system 37 is a mechanism that connects the input part 33 and the output part 38 in the latter stage of the rise of the bottom rail 14 and the slats 13, and has a third reduction ratio that is greater than the second reduction ratio. Among the three transmission systems 35, 36, and 37, the third transmission system 37 has the largest output torque and outputs a rotational force to the output part 38 at the slowest rotation speed.

[0055] Specifically, the third transmission system 37 includes a third input gear 67, a third switching clutch 68, and a third output gear 69. The third input gear 67 includes a third central opening 67a into which an input member 71 of the third switching clutch 68 is inserted. The inner peripheral surface of the third central opening 67a includes a third protrusion 67b for delaying the rotation of the third switching clutch 68 relative to the third input gear 67. A pair of the third protrusions 67b are provided at opposing positions. The third input gear 67 is always connected to the gear portion 43b of the input gear 43 constituting the input portion 33. The third switching clutch 68 starts to rotate after the third protrusion 67b hits the restricting protrusion 71c of the input member 71 of the third switching clutch 68. The third switching clutch 68 has a configuration substantially similar to that of the first switching clutch 62 and the second switching clutch 65, and will be described in detail later.

[0056] The third output gear 69 is connected to the output member 76 of the third switching clutch 68 and is meshed with the third transmission gear 55 constituting the switching unit 34. That is, in the third transmission system 37, the rotational force input from the input unit 33 is input to the third input gear 67, and the rotational force is transmitted from the third output gear 69 to the third transmission gear 55 of the switching unit 34. Here, the third output gear 69 is provided with a one-way clutch. The third output gear 69 transmits only the rotation in the direction that lifts the bottom rail 14 and the slats 13 to the third transmission gear 55, and the one-way clutch rotates idly during the reverse rotation. Specifically, when the first output gear 63 transmits the rotation to the first transmission gear 52 during the lifting of the bottom rail 14 and the slats 13, the third output gear 69 does not transmit the rotation to the third transmission gear 55 because the one-way clutch rotates idly. Furthermore, even when the second output gear 66 transmits rotation to the second transmission gear 54 , the third output gear 69 rotates idly and does not transmit rotation to the third transmission gear 55 .

[0057] [Switching clutch] The first changeover clutch 62, the second changeover clutch 65, and the third changeover clutch 68 will be described with reference to Figures 11 to 13. The first to third changeover clutches 62, 65, and 68 each include an input member 71, a first biasing member 72, a changeover member 73, a changeover shaft 74, a second biasing member 75, an output member 76, and a third biasing member 77.

[0058] The input member 71 includes a shaft portion 71a and a cylindrical portion 71b. The shaft portion 71a is a cylindrical portion, and supports the first to third input gears 61, 64, and 67 on its outer circumferential surface. The base end of the shaft portion 71a includes a restricting protrusion 71c with which the first to third protrusions 61b, 64b, and 67b engage. A pair of restricting protrusions 71c are provided at opposing positions. When the first to third input gears 61, 64, and 67 are inserted into the shaft portion 71a, the restricting protrusion 71c is disposed between the first to third protrusions 61b, 64b, and 67b. The first to third input gears 61, 64, and 67 and the input member 71 are relatively rotatable until the first to third protrusions 61b, 64b, and 67b engage with the restricting protrusion 71c. The input member 71 starts to rotate after the first to third projections 61b, 64b, 67b engage with the restricting projection 71c.

[0059] One end of a first biasing member 72 is disposed inside the cylindrical portion 71b. The first biasing member 72 is, for example, a coil spring. The first biasing member 72 elastically biases the switching member 73 in the direction of the switching shaft 74 relative to the input member 71. An inner peripheral surface of the cylindrical portion 71b is provided with an insertion recess 71e.

[0060] The switching member 73 includes a connection portion 73a and a switching piece 73b. The connection portion 73a has a cylindrical shape, and its outer circumferential surface includes an insertion protrusion 73c that engages with the insertion recess 71e. The connection portion 73a includes an insertion hole 73d in the center, into which the other end of the first biasing member 72 is inserted. The connection portion 73a includes a partition wall 73e on the inside against which the other end of the first biasing member 72 abuts. As a result, the switching member 73 is constantly biased in the direction of the switching shaft 74.

[0061] The switching piece 73b is an arcuate wall extending toward the switching shaft 74, and is provided over a range of approximately 100° from the center. A partition wall 73e located at the base end of the switching piece 73b includes a first irregularity 73f.

[0062] The switching shaft 74 includes a substrate 74a, a first shaft 74b, a second shaft 74c, and an operating piece 74d. The first shaft 74b is a shaft extending from the substrate 74a toward the switching member 73, passes through an insertion hole 73d, is inserted into the shaft portion 71a, and is fixed by a fixing member 74e such as a screw or a washer. The substrate 74a is a circular plate portion facing the partition wall 73e, and the surface facing the partition wall 73e includes a second uneven portion 74f that meshes with the first uneven portion 73f. The partition wall 73e is pressed against the substrate 74a by the biasing force of the first biasing member 72. In a state in which the convex portion of the first uneven portion 73f and the concave portion of the second uneven portion 74f, and the concave portion of the first uneven portion 73f and the convex portion of the second uneven portion 74f are meshed, the switching member 73 and the switching shaft 74 rotate integrally without being rotated relative to each other. In a state in which the convexities of the first unevenness 73f ride on the convexities of the second unevenness 74f against the biasing force of the first biasing member 72, the switching member 73 and the switching shaft 74 are able to rotate relative to each other.

[0063] The second shaft 74c extends in the opposite direction to the first shaft 74b with respect to the base plate 74a. The second shaft 74c is a connecting shaft with the output member 76. The base plate 74a is provided with an operating piece 74d on the outer side of the second shaft 74c. The operating piece 74d is an arc wall extending toward the output member 76 and is provided over a range of approximately 100° with respect to the center.

[0064] The second biasing member 75 is, for example, a torsion coil spring, and includes a coil portion, an arm portion extending from one end of the coil portion, and an arm portion extending from the other end of the coil portion. The output member 76 includes a first support portion 76a and a second support portion 76b. The first support portion 76a is a cylindrical portion, and the second shaft 74c is inserted into a central hole so as to be capable of relative rotation. The coil portion of the second biasing member 75 is supported on the outer periphery of the first support portion 76a. As shown in FIG. 14, when the switching shaft 74 and the output member 76 are connected, the switching piece 73b and the operating piece 74d are arranged so as not to overlap each other, and two gaps are provided between the switching piece 73b and the operating piece 74d. One of the two gaps is located in one of the gaps, and the other arm portion of the second biasing member 75 is located in the other gap.

[0065] The second support portion 76b has a different configuration between the first transmission system 35 and the second and third transmission systems 36, 37. The second support portion 76b of the first transmission system 35 is formed as a square pole and is inserted into the square central hole 63a of the first output gear 63. The second and third output gears 66, 69 are attached to the second support portion 76b of the second and third transmission systems 36, 37 so that they cannot rotate relative to each other. The second and third output gears 66, 69 have a rotation restriction groove 76d in the central hole 76c. The second support portion 76b has a rotation restriction protrusion 76e that is engaged with the rotation restriction groove 76d of the second and third output gears 66, 69. The second and third output gears 66, 69 are linked to the second support portion 76b by the rotation restriction protrusion 76e engaging with the rotation restriction groove 76d. The second and third output gears 66, 69 are equipped with one-way clutches, so that the second and third output gears 66, 69 and the output member 76 are connected when rotating in a direction that raises the bottom rail 14 and the slats 13, and are disconnected when rotating in a direction that lowers the bottom rail 14 and the slats 13.

[0066] The second support portion 76b of the second and third transmission systems 36, 37 further has a third biasing member 77 disposed at its base end. The third biasing member 77 is, for example, a torsion coil spring, and includes a coil portion, an arm portion extending from one end of the coil portion, and an arm portion extending from the other end of the coil portion. The coil portion of the third biasing member 77 is supported on the outer periphery of the second support portion 76b. A restricting wall provided on the case 32 is located between the pair of arms. The third biasing member 77 is provided on the second changeover clutch 65 and the third changeover clutch 68, in which a one-way clutch is provided on the output gear, and is not provided on the first changeover clutch 62, in which a one-way clutch is not provided on the output gear.

[0067] 14, the second biasing member 75 disposed on the first support portion 76a of the output member 76 has a pair of arms that open at approximately 130° with respect to the center of the coil portion. The second biasing member 75 divides the circumference of the coil portion into two sections by the two arms, with the switching piece 73b of the switching member 73 disposed in one section and the operating piece 74d of the switching shaft 74 disposed in the other section.

[0068] When the first concave-convex 73f and the second concave-convex 74f engage with each other and the switching shaft 74 rotates together with the switching member 73 in the upward direction to raise the bottom rail 14 and the slat 13, one arm 75a of the arm portions 75a and 75b of the second biasing member 75 abuts against one end of the operating piece 74d. Then, when the switching shaft 74 continues to rotate in the same direction, the coil portion of the second biasing member 75 contracts in diameter, and friction with the first support portion 76a of the output member 76 increases. This causes the rotation of the switching shaft 74 to be transmitted to the output member 76. Then, when a load of a predetermined value or more is applied, the first concave-convex 73f and the second concave-convex 74f are released from the engaged state against the biasing force of the first biasing member 72. Then, one end of the switching piece 73b abuts against the other arm portion 75b. As the switching shaft 74 continues to rotate in the same direction, the coil portion of the second biasing member 75 expands in diameter and rotates freely relative to the first support portion 76a. As a result, the rotation of the input member 71 and the switching member 73 is no longer transmitted to the switching shaft 74.

[0069] The load here is the load for winding when the bottom rail 14 and the slats 13 are raised, and increases as the slats 13 are piled up on the bottom rail 14 as they are raised. The load for disengaging the first unevenness 73f from the second unevenness 74f increases in the order of the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68. This is because the first switching clutch 62 functions in the early stage of raising the bottom rail 14 and the slats 13, the second switching clutch 65 functions in the middle stage, and the third switching clutch 68 functions in the later stage. That is, the clutches are harder to disengage in the order of the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68.

[0070] The ease of disengagement of the clutch is set by the biasing force of the first biasing member 72 and the shapes of the first and second unevennesses 73f and 74f. Here, the biasing force of the first biasing member 72 of the first shift clutch 62 increases in this order, followed by the biasing force of the first biasing member 72 of the second shift clutch 65 and the biasing force of the first biasing member 72 of the third shift clutch 68. Also, the first and second unevennesses 73f and 74f of the first shift clutch 62, the first and second unevennesses 73f and 74f of the second shift clutch 65, and the first and second unevennesses 73f and 74f of the third shift clutch 68 are shaped in this order to make it difficult for the meshing to come off by adjusting the inclination angles of the inclined surfaces. In addition, the first unevenness 73f and the second unevenness 74f may have the same shape as long as the biasing force of the first biasing member 72 in the first changeover clutch 62, the second changeover clutch 65, and the third changeover clutch 68 is in the above-mentioned order.

[0071] On the other hand, when the bottom rail 14 and the slats 13 are rotated in a downward direction to lower them, in the second switching clutch 65 and the third switching clutch 68, when the input member 71 and the switching member 73 rotate, the first unevenness 73f of the switching member 73 rotates in the downward direction and returns to a state in which it meshes with the second unevenness 74f. The second unevenness 74f does not rotate because the rotation of the output member 76 is restricted by the third biasing member 77, and it meshes with the first unevenness 73f. In the first switching clutch 62, the second unevenness 74f does not rotate because the rotation is restricted by the brake 39 (see FIG. 2) that suppresses the bottom rail 14 and the slats 13 from falling due to their own weight, and it meshes with the first unevenness 73f.

[0072] [Output section] As shown in Fig. 4, the output section 38 includes an output gear 81, a first reduction gear 82, and a second reduction gear 83. The output gear 81 includes a shaft hole 81a into which the output side guide rib 53i of the transmission shaft 53 is inserted. As a result, the output gear 81 is attached in a state in which it cannot rotate relative to the transmission shaft 53. The first reduction gear 82 is a two-stage gear, and a first stage surface meshes with the output gear 81 and a second stage surface meshes with the second reduction gear 83. The first reduction gear 82 and the second reduction gear 83 are journaled on a shaft portion provided in the case 32. The second reduction gear 83 is connected to the brake 39.

[0073] [Operation of the embodiment] The horizontal blind 10 configured as above has the following effects. [When raising the bottom rail and slats] When the bottom rail 14 and the slats 13 are raised from their lowest positions, the front hanging portion of the operating cord 21a is pulled downward. Then, in the input section 33, when the first input shaft 41 is rotated in the upward direction, the directly connected second input shaft 44 also rotates in the same direction, and the clutch drum 51 also rotates in the same direction. Then, the clutch drum 51 located on the input section 33 side (state of FIG. 9) is biased toward the output section 38 side (state of FIG. 10). As a result, the locking claw 53f of the transmission shaft 53 engages with the engagement recess 54b of the second transmission gear 54, and the locking claw 53g of the third transmission gear 55 engages with the engagement recess 55b of the third transmission gear 55. As a result, the second transmission gear 54 and the third transmission gear 55 are in a state in which they can rotate integrally with the transmission shaft 53.

[0074] On the other hand, the rotational force is transmitted from the input portion 33 to the first transmission system 35 to the third transmission system 37 with a delay with respect to the transmission shaft 53. That is, when the first input shaft 41 rotates, the input gear 43 does not rotate until both the first engaging protrusion 41f and the inner protrusion 42a and the outer protrusion 42b and the second engaging protrusion 43d are engaged, and starts to rotate after both are engaged. Furthermore, the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68 start to rotate after the first to third protrusions 61b, 64b, and 67b of the first input gear 61, the second input gear 64, and the third input gear 67 engage with the regulating protrusion 71c. In this way, the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68 start to rotate with a delay with respect to the rotation of the first input shaft 41. As a result, once the second transmission gear 54 and the third transmission gear 55 are able to rotate integrally with the transmission shaft 53, the rotational force is transmitted to each of the first to third transmission systems 35-37. In other words, the bias of the clutch drum 51 from the input portion 33 side to the output portion 38 side is completed before a delay period generated by the input portion 33 and a delay period generated by each of the transmission systems 35-37 described below have elapsed.

[0075] Incidentally, the reduction ratios of the first transmission system 35 to the third transmission system 37 are larger in this order. Therefore, the first rotation speed of the first output gear 63 of the first transmission system 35, the second rotation speed of the second output gear 66 of the second transmission system 36, and the third rotation speed of the third output gear 69 of the third transmission system 37 are slower in this order. As shown in FIG. 15, in the transmission shaft 53, the rotation of the first rotation speed is input from the first output gear 63 to the first transmission gear 52, the rotation of the second rotation speed is input from the second output gear 66 to the second transmission gear 54, and the rotation of the third rotation speed is input from the third output gear 69 to the third transmission gear 55. Here, the second output gear 66 and the third output gear 69 are provided with one-way clutches. Therefore, the one-way clutch portion of the second output gear 66 rotates idly relative to the second transmission gear 54, and the one-way clutch portion of the third output gear 69 rotates idly relative to the third transmission gear 55. Therefore, the transmission shaft 53 rotates at the first rotation speed, which is the fastest rotation speed. In other words, the second transmission gear 54 rotating at the second rotation speed and the third transmission gear 55 rotating at the third rotation speed do not collide with the transmission shaft 53 rotating at the first rotation speed.

[0076] As shown in FIG. 16, in the initial stage of raising the bottom rail 14 and the slats 13 from their lowermost positions, the rotation input to the input section 33 is transmitted to the output section 38 through the first input gear 61, the first switching clutch 62, the first output gear 63, and the first transmission gear 52, which constitute the first transmission system 35. Then, the winding section 24 connected through the drive shaft 20 starts winding the lifting cord 15. In the initial stage of winding, the load for winding is about the sum of the weight of the bottom rail 14 and the weight of several slats 13, which is relatively light. For this reason, the reduction ratio is set to prioritize the rising speed over the output torque. As the bottom rail 14 rises, the number of slats 13 piled up on the bottom rail 14 also increases, and the load also increases accordingly.

[0077] Then, the first unevenness 73f and the second unevenness 74f of the first changeover clutch 62 are disengaged, the coil portion of the second biasing member 75 expands in diameter, and the first output gear 63 integrated with the output member 76 stops rotating. As a result, rotation is no longer transmitted from the first transmission system 35 to the transmission shaft 53. At the same time, rotation is transmitted to the transmission shaft 53 through the second transmission system 36. That is, as shown in FIG. 17, rotation at the second rotation speed is input from the second output gear 66 to the second transmission gear 54, and rotation at the third rotation speed is input from the third output gear 69 to the third transmission gear 55. In the first transmission system 35, rotation is no longer transmitted to the first output gear 63 because the first changeover clutch 62 is disengaged, and the one-way clutch portion of the third output gear 69 rotates idly relative to the third transmission gear 55. Therefore, the transmission shaft 53 is rotated at the second rotation speed which is the second fastest.

[0078] As shown in FIG. 18, in the middle stage of lifting the bottom rail 14 and the slats 13, the driving force transmission unit 31 also switches from the first transmission system 35 to the second transmission system 36, and a considerable number of slats 13 are piled up on the bottom rail 14. In the middle stage, the rotation input to the input unit 33 is transmitted to the output unit 38 through the second input gear 64, the second switching clutch 65, the second output gear 66, and the second transmission gear 54 that constitute the second transmission system 36. Then, the winding unit 24 connected through the drive shaft 20 winds up the lifting cord 15. Then, as the bottom rail 14 rises, the number of slats 13 piled up on the bottom rail 14 gradually increases, and the load also gradually increases accordingly.

[0079] Then, the first concave-convex 73f and the second concave-convex 74f of the second switching clutch 65 are disengaged, the coil portion of the second biasing member 75 expands in diameter, and the second output gear 66 integrated with the output member 76 does not rotate. As a result, rotation is not transmitted to the transmission shaft 53 from the second transmission system 36 in addition to the first transmission system 35. At the same time, rotation is transmitted to the transmission shaft 53 through the third transmission system 37. That is, as shown in FIG. 19, rotation at the third rotation speed is input from the third output gear 69 to the third transmission gear 55, and rotation at the third rotation speed is input from the third output gear 69 to the third transmission gear 55. In the first transmission system 35, the first switching clutch 62 is disengaged, so that rotation is not transmitted to the first output gear 63. In the second transmission system 36, the second switching clutch 65 is disengaged, so that rotation is not transmitted to the second output gear 66. Therefore, the transmission shaft 53 is rotated at the third rotation speed which is the slowest rotation speed.

[0080] As shown in FIG. 20, in the latter stage of lifting the bottom rail 14 and the slats 13, almost all of the slats 13 are piled up on the bottom rail 14. In the latter stage, the rotation input to the input unit 33 is transmitted to the output unit 38 through the third input gear 67, the third switching clutch 68, the third output gear 69, and the third transmission gear 55, which constitute the third transmission system 37. Then, the winding unit 24 connected through the drive shaft 20 winds up the lifting cord 15. In the later stage of winding, the load on the winding is the weight of the bottom rail 14 plus the weight of several slats 13, which is the largest. For this reason, the reduction ratio is set to prioritize the output torque over the lifting speed.

[0081] In addition, when an excessive load is applied because the rising bottom rail 14 or the stacked slats 13 get caught on an obstacle, the first unevenness 73f and the second unevenness 74f of the third switching clutch 68 are disengaged. Then, the coil part of the second biasing member 75 expands in diameter, and the third output gear 69 integrated with the output member 76 does not rotate. Also, when the upper limit is reached by the upward operation, the first unevenness 73f and the second unevenness 74f of the third switching clutch 68 are disengaged, and the coil part of the second biasing member 75 expands in diameter, and the third output gear 69 integrated with the output member 76 does not rotate. In this respect, the third switching clutch 68 also realizes a fail-safe function. In addition, the failure of the driving force transmission unit 31 is suppressed.

[0082] FIG. 21 is a diagram showing the relationship between the height of the bottom rail 14 during ascent and the rotational speed when the speed at which the operating cord 21a of the winding unit 24 is pulled is constant. In the initial stage when the bottom rail 14 starts to rise from the lower limit position, the winding unit 24 rotates at a rotational speed according to the reduction ratio of the first transmission system 35. The rotational speed at this time is the fastest, and the output torque is the smallest. Then, in the middle stage, the winding unit 24 rotates at a rotational speed according to the second transmission system 36 having a second reduction ratio greater than the first reduction ratio. The rotational speed at this time is one step slower than in the initial stage, and the output torque is one step higher than in the initial stage. In the later stage, the winding unit 24 rotates at a rotational speed according to the third reduction ratio of the third transmission system 37 having a greater than the second reduction ratio. The rotational speed at this time is the slowest, and the output torque is the largest.

[0083] 22 is a diagram showing the relationship between the height of the bottom rail 14 during ascent and the rotational speed of each of the switching clutches 62, 65, 68. In the early stage when the bottom rail 14 starts to rise from the lower limit position, the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68 are all rotating. In the middle stage, the first switching clutch 62 is disengaged, and the second switching clutch 65 and the third switching clutch 68 are rotating. Then, in the later stage, the first switching clutch 62 and the second switching clutch 65 are disengaged, and only the third switching clutch 68 is rotating.

[0084] 23 is a diagram showing the relationship between the height of the bottom rail 14 during ascent and the operating force pulling the operating cord 21a downward. In the early stage when the bottom rail 14 starts to rise from the lowest position, the operating force gradually increases until it switches from the first transmission system 35 to the second transmission system 36, and then decreases as it switches to the second transmission system 36. In the middle stage, the operating force gradually increases until it switches from the second transmission system 36 to the third transmission system 37, and then decreases as it switches to the third transmission system 37. In the later stage, the operating force gradually increases until the bottom rail 14 reaches the upper limit position.

[0085] The output torque of the first transmission system 35, the second transmission system 36, and the third transmission system 37 increases in this order, so that the bottom rail 14 can be raised to the upper limit position with a similar operating force from the early stage to the later stage. However, the raising speed becomes slower as it approaches the upper limit position.

[0086] [When lowering the bottom rail and slats] When the bottom rail 14 and the slats 13 are lowered from the upper limit position, the hanging portion at the rear side of the operating cord 21a is pulled downward. Then, in the input section 33, when the first input shaft 41 is rotated in the downward direction, the directly connected second input shaft 44 also rotates in the same direction, and the clutch drum 51 also rotates. Then, the clutch drum 51 located on the output section 38 side (state of FIG. 10) is biased toward the input section 33 side (state of FIG. 9). As a result, the engagement state of the locking claw 53f of the transmission shaft 53 and the engagement recess 54b of the second transmission gear 54 is released, and the engagement state of the locking claw 53g of the transmission shaft 53 and the engagement recess 55b of the third transmission gear 55 is released. The second transmission gear 54 and the third transmission gear 55 are in an idling state with respect to the transmission shaft 53.

[0087] Furthermore, the rotational force is transmitted from the input unit 33 to the first transmission system 35 to the third transmission system 37 with a delay relative to the transmission shaft 53. That is, the rotational force is transmitted to the switching clutches 62, 65, and 68 of the first transmission system 35 to the third transmission system 37 after the second transmission gear 54 and the third transmission gear 55 are disconnected from the transmission shaft 53.

[0088] The transmission shaft 53 rotates only by the first transmission gear 52, and the second transmission gear 54 and the third transmission gear 55 are in an idling state with respect to the transmission shaft 53. Therefore, the second transmission gear 54 rotating at the second rotational speed and the third transmission gear 55 rotating at the third rotational speed do not collide with the transmission shaft 53 rotating at the first rotational speed. Only the rotation of the first changeover clutch 62 is transmitted to the first transmission gear 52, and the transmission shaft 53 rotates in the downward direction at the first rotational speed.

[0089] At this time, the first unevenness 73f and the second unevenness 74f of the first changeover clutch 62 return from a disengaged state to an engaged state. The first unevenness 73f and the second unevenness 74f of the second changeover clutch 65 and the third changeover clutch 68 return from a disengaged state to an engaged state.

[0090] Thus, the bottom rail 14 and the slats 13 are lowered from the upper limit position to the lower limit position by only the first transmission system 35. That is, the rotation input to the input part 33 is transmitted to the output part 38 through the first input gear 61, the first switching clutch 62, and the first output gear 63 that constitute the first transmission system 35 (see FIG. 16). Then, the winding part 24 connected through the drive shaft 20 winds out the lifting cord 15, and the bottom rail 14 is lowered.

[0091] 24 is a diagram showing the relationship between the height of the bottom rail 14 during descent and the rotation speed when the speed at which the operating cord 21a of the winding part 24 is pulled is constant. When the bottom rail 14 is lowered, the first transmission system 35 is used until it reaches the lowest position. Therefore, the winding part 24 rotates at a rotation speed according to the reduction ratio of the first transmission system 35.

[0092] 25 is a diagram showing the relationship between the height of the bottom rail 14 and the rotational speed of each of the switching clutches 62, 65, 68. In each of the first switching clutch 62, the second switching clutch 65, and the third switching clutch 68, the rotation of the input gear 43 is input to the first input gear 61 of the first transmission system 35, the second input gear 64 of the second transmission system 36, and the third input gear 67 of the third transmission system 37, respectively, and rotates at a rotational speed according to each reduction ratio. However, the rotation transmitted to the output unit 38 is only the rotation via the first transmission system 35.

[0093] 26 is a diagram showing the relationship between the height of the bottom rail 14 and the operating force for pulling the operating cord 21a downward. When the bottom rail 14 moves from the upper limit position to the lower limit position, rotation is transmitted from the input unit 33 to the output unit 38 via the first transmission system 35, and the operating force at that time gradually increases.

[0094] [Effects of the embodiment] The horizontal blind 10 as described above can provide the following effects. (1-1) When the bottom rail 14 and slats 13 of the horizontal blind 10 rise from the lower limit position to the upper limit position, they become heavier as they rise, and the load on the operation of raising them increases. In the initial stage when the bottom rail 14 and slats 13, which are comparatively light in weight, start to rise, the driving force transmission unit 31 can increase the rising speed by selecting the first transmission system 35, which has a relatively small reduction ratio. Then, in the middle stage following the initial stage, the second transmission system 36, which has a larger reduction ratio than the first transmission system 35, is selected to slightly slow the rising speed and reduce the operating force. Then, in the later stage following the middle stage, the third transmission system 37, which has a larger reduction ratio than the second transmission system 36, is selected to slow the rising speed and reduce the operating force.

[0095] In this way, the horizontal blind 10 switches the transmission system in three stages when raising the bottom rail 14 and the slats 13. This allows the bottom rail 14 and the slats 13 to rise faster near the lowest position, and the operating force becomes lighter as they rise, improving the balance between operating force and operating time.

[0096] (1-2) The switch from the first transmission system 35 to the second transmission system 36 is performed continuously, i.e., instantly, by disengaging the first changeover clutch 62. The switch from the second transmission system 36 to the third transmission system 37 is also performed continuously, i.e., instantly, by disengaging the second changeover clutch 65. Therefore, by simply pulling the operating cord 21a continuously, the bottom rail 14 and the slats 13 can be continuously raised from the lower limit position to the upper limit position without temporary stops.

[0097] (1-3) When lowering the bottom rail 14 and the slats 13 from the upper limit position to the lower limit position, a large operating force is not required. Therefore, the first transmission system 35, which has the fastest rotation speed, is used. This makes it possible to prevent the lowering speed of the bottom rail 14 and the slats 13 from slowing down.

[0098] (1-4) The switching between raising and lowering the bottom rail 14 and the slats 13 can be achieved by using the clutch drum 51 to move the transmission shaft 53 and switch between connecting and disconnecting the second transmission gear 54 and the third transmission gear 55.

[0099] (1-5) When the bottom rail 14 and the slats 13 are raised, rotations at different speeds are input to the transmission shaft 53 from each of the first transmission system 35, the second transmission system 36, and the third transmission system 37. The second transmission system 36 has a second output gear 66 at a connection portion with the transmission shaft 53, and the third transmission system 37 has a third output gear 69 at a connection portion with the transmission shaft 53. The second output gear 66 and the third output gear 69 are equipped with one-way clutches.

[0100] Therefore, when the rotation of the first transmission system 35 is being transmitted to the transmission shaft 53, the slower rotation from the second and third transmission systems 36, 37 can be cut off by the one-way clutches of the second and third output gears 66, 69 rotating idly. In addition, when the rotation of the second transmission system 36 is being transmitted to the transmission shaft 53, the slower rotation from the third transmission system 37 can be cut off by the one-way clutch of the third output gear 69 rotating idly.

[0101] (1-6) When an excessive load is applied because the rising bottom rail 14 or the stacked slats 13 get caught on an obstacle, the third output gear 69 of the third switching clutch 68 stops rotating. Also, when the upper limit is reached during the raising operation, the third output gear 69 stops rotating. In this respect, the third switching clutch 68 can also realize a fail-safe function. Also, the failure of the driving force transmission unit 31 can be suppressed.

[0102] The horizontal blind 10 can also be modified as follows. In the driving force transmission unit 31 including the first transmission system 35, the second transmission system 36, and the third transmission system 37, the third transmission system 37 may omit the third switching clutch 68. This is because the fail-safe function can also be achieved by other components.

[0103] When lowering the bottom rail 14 and the slats 13, the second transmission system 36 or the third transmission system 37 may be used instead of the first transmission system 35.

[0104] The number of transmission systems is not limited to three, as long as there are at least two with different reduction ratios. If there are four or more, the transmission systems can be switched more precisely, and the change in the operating force required to raise the bottom rail 14 and the slats 13 from the lower limit position to the upper limit position can be reduced.

[0105] The switching between the first transmission system 35, the second transmission system 36, and the third transmission system 37 may be performed when the bottom rail 14 and the slats 13 are lowered. Also, it may be performed both when they are raised and lowered. In the case where it is performed both when they are raised and lowered, a driving force transmission unit for raising and a driving force transmission unit for lowering are provided.

[0106] The shading device may be one in which the load during operation changes as the shading material is moved. That is, in the case of vertical blinds, the load gradually increases when moving from a closed state in which the slats separate the space to an open state. Therefore, by providing a drive force transmission unit as described above, the change in the operating force required to move the slats in the opening direction can be reduced. In addition, the load increases as the screen rises for pleated screens and roller screens, so by providing a drive force transmission unit as described above, the change in the operating force required to raise the screen can be reduced. [Explanation of symbols]

[0107] 31...Drive force transmission section 33...Input section 34…Switching section 35…First transmission system 36...Second transmission system 37…Third transmission system 38...Output section 51…Clutch drum 52…First transmission gear 53...Transmission shaft 54…Second transmission gear 55…Third transmission gear 61…1st input gear 62…First changeover clutch 63…1st output gear 64…Second output gear 65…Second changeover clutch 66…Second output gear 67…Third input gear 68…Third changeover clutch 69…Third output gear 71... Input member 72...First biasing member 73...Switching member 74…Switching axis 75...Second biasing member 76...Output member 77...Third biasing member

Claims

1. A moving unit that moves the shielding material suspended from the head box; an operating unit that is operated to move the shielding material in a first direction in which the amount of the shielding material increases and in a second direction that is opposite to the first direction; a driving force transmission unit that transmits a driving force from the operation unit to the moving unit, the driving force transmission unit includes a plurality of transmission systems that transmit the driving force to the moving unit by gears; an output unit that outputs the driving force from any one of the transmission systems to the moving unit, The plurality of transmission systems include at least a first transmission system that transmits the driving force to the moving part at a first reduction ratio in a first section from a start of operation; a second transmission system that is continuously switched from the first transmission system in a second section subsequent to the first section to transmit the driving force to the moving part at a second reduction ratio different from the first reduction ratio; When the shielding material is moved in the first direction, the driving force transmission unit transmits the driving force to the moving unit through the first transmission system, and then continuously transmits the driving force to the moving unit through the second transmission system; When the shielding material is moved in the second direction, the driving force is transmitted to the moving part through the first transmission system. Shielding device.

2. a switching unit that enables the driving force to be transmitted to the first transmission system and the second transmission system when the shielding material is moved in the first direction, and enables the driving force to be transmitted to the first transmission system when the shielding material is moved in the second direction; The shielding device of claim 1 .

3. the first transmission system includes a first switching clutch that disconnects the first transmission system when a first load is applied; The second transmission system includes a second switching clutch that disconnects the second transmission system when a second load different from the first load is applied, and a one-way clutch that rotates idly relative to the output section when the operation in the first direction is being performed and the first switching clutch connects the first transmission system.

3. A shielding device according to claim 1 or 2.

4. The first direction is an ascending direction of the shielding material, The second direction is a downward direction of the shielding material, The first reduction ratio is smaller than the second reduction ratio. Shielding device according to any one of claims 1 to 3.

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