BLIND

Abstract

This invention provides a blind that can improve shading performance in the fully closed state without requiring a new cord to tilt the slats more vertically. [Solution] The blind has multiple lifting cords that can raise and lower multiple slats which are tiltably supported by ladder cords. Among the multiple lifting cords, there is a lifting member 41 that is connected to the bottom rail and is provided to be able to pull up a lifting cord that can be relaxed when the slats are fully closed. When the lifting cord becomes relaxed as the drive shaft rotates in the downward direction of the slats at the upper limit position of the slats, the lifting member 41 moves from a first position where the rotation of the drive shaft cannot be transmitted to a second position where the rotation of the drive shaft can be transmitted, and the lifting mechanism 14 operates the lifting member 41 located in the second position to pull up the lifting cord as the drive shaft rotates in the downward direction of the slats, thereby tilting the bottom rail upward.

Description

Technical Field

[0001] The present invention relates to a blind, and particularly to a horizontal blind that raises and lowers slats by means of lifting cords.

Background Art

[0002] Conventionally, a blind disclosed in Patent Document 1 below is known. This blind includes a shielding cord capable of lifting either end in the front-rear direction of a number of slats supported by a ladder cord, and a slat angle adjusting device configured to be able to raise and lower this shielding cord with an operating device. The shielding cord hangs down on either one of the front-rear directions of the number of slats and is connected to each of the number of slats.

[0003] According to such a configuration, in the fully closed state, the slats can be tilted more vertically. In particular, since the slats near the bottom rail that are difficult to tilt vertically can also be tilted more vertically, the shielding property in the fully closed state of the slats can be improved.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional blind, it is necessary to perform the work of connecting the shielding cord provided for lifting the end of the slat to each of the number of slats. Specifically, the shielding cord and each slat are connected by inserting each slat through a loop formed in the shielding cord, or the shielding cord formed with a spherical locking portion is inserted through a small-diameter insertion hole formed in the slat to connect the shielding cord and each slat.

[0006] Therefore, there was an installation challenge in that connecting the shading cords to the slats was time-consuming. In addition, there were concerns that the newly installed shading cords, hanging down in front of and behind the slats, might interfere with other cords, and that the exposed shading cords on the blind surface would reduce the aesthetic appeal.

[0007] Therefore, the problem that the present invention aims to solve is to provide a blind that can improve the shielding performance in the fully closed state without requiring a new cord to tilt the slats more vertically. [Means for solving the problem]

[0008] The inventors believed that the above problems could be solved by using a lifting cord that allows multiple slats to be raised and lowered to tilt the bottom rail upward, and based on this, they invented the following new blind.

[0009] (1) The blind according to the present invention is a blind having a plurality of lifting cords that can raise and lower a plurality of slats that are tiltably supported by a ladder cord, and has a lifting member provided to be able to pull up a lifting cord that is connected to a bottom rail and can be relaxed when the slats are in a fully closed state, and when the lifting cord that can be relaxed becomes relaxed as the drive shaft rotates in the downward direction of the slats at the upper limit position of the slats, the lifting mechanism moves the lifting member from a first position where the rotation of the drive shaft cannot be transmitted to a second position where the rotation of the drive shaft can be transmitted, and operates the lifting member located at the second position to pull up the relaxed lifting cord as the drive shaft rotates in the downward direction of the slats, thereby tilting the bottom rail upward.

[0010] (2) In the above (1), the lifting mechanism further comprises a rotation transmission member that is rotatably mounted integrally with the drive shaft and capable of transmitting the rotation of the drive shaft to the lifting member located at the second position, wherein the lifting member has a slackening lifting cord routed around a part of it, and preferably rotates integrally with the rotation transmission member to lift the slackening lifting cord.

[0011] (3) In (1) or (2) above, the lifting mechanism further comprises a biasing means for biasing the lifting member from the first position to the second position, wherein the lifting member is held in the first position by the tension of the slacken lifting cord routed to a part of it when the slacken lifting cord is in a taut state, and moves to the second position by the biasing force of the biasing means when the slacken lifting cord becomes slack.

[0012] (4) In the above (2), it is preferable to further include a restricting means for restricting the rotation of the lifting member by a predetermined amount or more, and an idler mechanism that operates to prevent the rotation input from the drive shaft from being transmitted to the lifting member when the drive shaft rotates in the slat downward direction with a torque of a predetermined amount or more while the rotation of the lifting member is restricted by the restricting means.

[0013] (5) In (1) above, it is preferable that the slacken lifting cord is connected to the front side or the rear side of the bottom rail. [Effects of the Invention]

[0014] The blind according to the present invention has a configuration that allows the bottom rail to be tilted upward using a lifting cord that can raise and lower multiple slats. Therefore, it is possible to provide a blind that can improve the shielding performance in the fully closed state without requiring a new cord to tilt the slats more vertically. [Brief explanation of the drawing]

[0015] [Figure 1] This is a front view showing a blind according to one embodiment of the present invention. [Figure 2] This is a perspective view showing an example of a lifting and rotating device applied to a blind according to one embodiment of the present invention. [Figure 3] This is an exploded perspective view showing an example of a lifting and rotating device applied to a blind according to one embodiment of the present invention. [Figure 4] This is an exploded perspective view showing an example of a freewheeling mechanism applied to a blind according to one embodiment of the present invention. [Figure 5] This is a cross-sectional view AA in Figure 2. [Figure 6] Figure 2 is a cross-sectional view of BB, where (a) shows the lifting member in the first position, (b) shows the lifting member in the second position, (c) shows the lifting member in the middle of rotation, and (d) shows the lifting member after rotation. [Figure 7] This is a side view showing an example of a lifting and rotating device applied to a blind according to one embodiment of the present invention, where (a) shows the state in which the lifting member is in the first position, (b) shows the state in which the lifting member is in the second position, (c) shows the state in which the lifting member is in the process of rotating, and (d) shows the state after the lifting member has rotated. [Figure 8] This is a side view showing the lower end of a blind according to one embodiment of the present invention, where (a) shows the state before the lifting mechanism is operated and (b) shows the state after the lifting mechanism is operated. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[0017] As shown in Figure 1, the blind 1 of this embodiment is installed, for example, in an opening such as a window frame of a building. The blind 1 is installed in a room separated from the outside of the building by a windowpane or the like. The blind 1 of this embodiment is typically a horizontal blind and has multiple lifting cords 4 that can raise and lower multiple slats 3 which are tiltably supported by multiple ladder cords 2. In this specification, when the blind 1 is installed, the longitudinal direction of the slats 3 is defined as the left - right direction, the up - down direction is perpendicular to the left - right direction, and the front - back direction is perpendicular to both the left - right and up - down directions. Also, regarding the front - back direction, the indoor side is the front, and the outdoor side is the back.

[0018] The blind 1 includes a C - shaped channel - like head box 5 at the top. The head box 5 is fixed to a window frame, wall, ceiling, etc. via brackets not shown. Thereby, the blind 1 is arranged inside the window.

[0019] A drive shaft 6 is rotatably provided inside the head box 5. When the drive shaft 6 is provided inside the head box 5, the axial direction J1 of the drive shaft 6 is along the longitudinal direction of the head box 5. The drive shaft 6 is rotatable about its own axis when provided inside the head box 5. One end of the axial direction J1 of the drive shaft ⑥ is connected to an operation unit 7 arranged inside the head box 5. A pulley 8 is rotatably provided on the operation unit 7 on the side opposite to the side where one end of the drive shaft 6 is connected. A loop - shaped operation cord 9 is wound around the pulley 8. The operation unit 7 can transmit the rotation of the pulley 8 caused by the operation of the operation cord 9 to the drive shaft 6. Therefore, the blind 1 can rotate the drive shaft 6 about its own axis by operating the operation cord 9.

[0020] The drive shaft 6 penetrates through a plurality of lifting and rotating devices 10 provided inside the head box 5. In the illustrated example, the blind 1 has three lifting and rotating devices 10. The three lifting and rotating devices 10 are arranged along the longitudinal direction of the head box 5 at intervals from each other. Here, the lifting and rotating device 10 located in the center among the three lifting and rotating devices 10 will be described. As shown in FIGS. 2 to 7, the lifting and rotating device 10 includes a rotating drum 11, a winding drum 12, a differential shaft 13, a pulling mechanism 14, an idling mechanism 15, and a drum receiver 16. <>

[0021] The rotating drum 11 has a drum portion 17, a first shaft portion 18, and a second shaft portion 19. The drum portion 17 is cylindrical and aligns with the axial direction J1 of the drive shaft 6. The outer diameter of the central part of the drum portion 17 in the axial direction J1 is smaller than the outer diameters of both ends of the drum portion 17 in the axial direction J1. The first shaft portion 18 is provided at one end of the drum portion 17 in the axial direction J1. The first shaft portion 18 is cylindrical and protrudes from the drum portion 17 along the axial direction J1 of the drive shaft 6. The outer circumferential surface of the first shaft portion 18 is provided with an annular recess 20 that is recessed radially inward. The recess 20 is located midway along the axial direction J1 of the first shaft portion 18. The second shaft portion 19 is provided at the other end of the drum portion 17 in the axial direction J1. The second shaft portion 19 is a stepped cylindrical shape and protrudes from the drum portion 17 along the axial direction J1 of the drive shaft 6. The second shaft portion 19 has a large-diameter portion 21 located at one end of the axial direction J1 and a small-diameter portion 22 located at the other end of the axial direction J1. A pair of protrusions 23, 23 are provided on the outer circumferential surface of the small-diameter portion 22 of the second shaft portion 19. The pair of protrusions 23, 23 are opposite each other in the radial direction of the small-diameter portion 22 of the second shaft portion 19 and protrude outward from the outer circumferential surface of the small-diameter portion 22 of the second shaft portion 19. The rotating drum 11 with this configuration has a through hole 24 along the axial direction J1. The through hole 24 penetrates the axis of the drum portion 17, the axis of the first shaft portion 18, and the axis of the second shaft portion 19. In the illustrated example, the vertical cross-sectional shape of the through-hole 24 is rectangular, but it is not limited to this and can be any non-circular shape.

[0022] One end of the ladder cord 2 is moored to the rotating drum 11. As shown in Figure 1, multiple slats 3 are attached to the ladder cord 2. Specifically, the slats 3 are attached to the ladder cord 2 so that their longitudinal direction is aligned with the left-right direction. With the multiple slats 3 attached to the ladder cord 2, the multiple slats 3 are spaced apart in the vertical direction. In this way, the multiple slats 3 are suspended from the headbox 5. The other end of the ladder cord 2 is connected via the ladder holder 25 to the bottom rail 26, which is located below the lowest slat 3.

[0023] The winding drum 12 is cylindrical and oriented along the axial direction J1 of the drive shaft 6. A circular flange 27 is provided at one end of the winding drum 12 along the axial direction J1. A circular plate-shaped lifting cord receiver 28, which extends in a flange-like manner, is provided at the other end of the winding drum 12 along the axial direction J1. A projection 29 is provided on the lifting cord receiver 28 on the other end side of the winding drum 12 along the axial direction J1. The projection 29 is substantially arc-shaped and protrudes from the lifting cord receiver 28. A pair of ribs (not shown) are provided on the inner circumferential surface of the winding drum 12. This pair of ribs are opposite each other in the radial direction of the winding drum 12 and protrude inward from the inner circumferential surface of the winding drum 12.

[0024] A lifting cord 4, which is a separate component from the ladder cord 2, is connected to the winding drum 12 in a way that allows it to be wound up and unwound. The lifting cord 4 can be wound onto the outer surface of the winding drum 12 and can be unwound from the outer surface of the winding drum 12. One end of the lifting cord 4 is anchored to the winding drum 12. In the illustrated example, one end of the lifting cord 4 is connected to the lifting cord receiver 28. The other end of the lifting cord 4 is connected to the front end of the bottom rail 26, which is in a nearly horizontal state before tilting upward, via a ladder holder 25.

[0025] The differential shaft 13 is cylindrical and aligns with the axial direction J1 of the drive shaft 6. A pair of ribs 30, 30 are provided on the outer circumferential surface of the differential shaft 13. The pair of ribs 30, 30 are facing each other radially on the differential shaft 13 and protrude outward from the outer circumferential surface of the differential shaft 13. The pair of ribs 30, 30 protrude beyond the differential shaft 13 towards one end of the axial direction J1 of the differential shaft 13. The pair of ribs 30, 30 are provided on the outer circumferential surface of the differential shaft 13, leaving the other end of the axial direction J1 of the differential shaft 13 untouched. A circular flange portion 31 is provided on the differential shaft 13 at the other end of the axial direction J1 where the pair of ribs 30, 30 are not provided. The flange portion 31 is provided at the other end of the axial direction J1 of the differential shaft 13, in the middle of the axial direction J1 of the differential shaft 13.

[0026] A hollow stopper housing portion 32 is provided on the flange portion 31 at the other end side in the axial direction J1 of the differential shaft 13. The stopper housing portion 32 protrudes from the upper end of the flange portion 31 and has an arc-shaped outer surface that follows the circular flange portion 31. The stopper housing portion 32 opens in a direction perpendicular to the axial direction J1 of the differential shaft 13. Specifically, the stopper housing portion 32 has openings 33, 33 at one end and the other end of the arc-shaped outer surface. A notched slit 34 is provided in the stopper housing portion 32 at one end side in the axial direction J1 of the differential shaft 13, connecting the inside and outside of the stopper housing portion 32. That is, the slit 34 is formed in the flange portion 31. The stopper housing section 32 is provided with a slit 35 that connects the inside and outside of the stopper housing section 32 at the other end of the differential shaft 13 in the axial direction J1.

[0027] The stopper housing section 32 houses the stopper 36 and the stopper spring 37. The stopper 36 is a roughly rectangular block. The stopper 36 is provided with a claw portion 38. The claw portion 38 protrudes outward from the stopper 36. The stopper 36 is provided with a projection 39 that is inserted into the slit 34 and a projection 40 that is inserted into the slit 35. Both projections 39 and 40 protrude outward from the stopper 36. The stopper spring 37 is typically a coil spring.

[0028] The stopper 36 is movably provided within the stopper housing 32. Specifically, the stopper 36 is provided within the stopper housing 32 with its projection 39 inserted into the slit 34 and its projection 40 inserted into the slit 35. This allows the stopper 36 to move along the slit 35. In this way, the stopper 36 is movable within the stopper housing 32 in a direction perpendicular to the axial direction J1 of the differential shaft 13. With the stopper 36 positioned within the stopper housing 32, the stopper spring 37 is provided between the stopper 36 and a protrusion (not shown) within the stopper housing 32. One end of the stopper spring 37 is in contact with the stopper 36, and the other end of the stopper spring 37 is in contact with the protrusion of the stopper housing 32.

[0029] The lifting mechanism 14 can tilt the bottom rail 26 upward by pulling up the lifting cord 4 through the rotation of the drive shaft 6. In the blind 1 of this embodiment, the lifting mechanism 14 includes a lifting member 41, a rotation transmission member 42, and a biasing means 43.

[0030] The lifting member 41 has a shaft insertion piece 44, an extension piece 45, and a roller 46. The shaft insertion piece 44 is plate-shaped, with its plate surface facing the axial direction J1 of the drive shaft 6. The shaft insertion piece 44 has an insertion hole 47 that penetrates the axial direction J1 of the drive shaft 6. The insertion hole 47 is elongated in shape, for example, roughly oval. An extension piece 45 is provided on the shaft insertion piece 44. The extension piece 45 is elongated in shape, along the axial direction J1 of the drive shaft 6. The extension piece 45 extends from the end of the shaft insertion piece 44 to the other end of the axial direction J1 of the drive shaft 6. The extension piece 45 has an engaging portion 48 that engages with a rotation transmission member 42, which will be described later. The engaging portion 48 protrudes inward from the inner surface of the extension piece 45. A roller 46 is provided on the extension piece 45 via a bifurcated roller support portion 49. The roller 46 is positioned to span the space between the bifurcated portions of the roller support portion 49. When the roller 46 is supported by the roller support portion 49 on the extension piece 45, the axis of the roller 46 is aligned with the axial direction J1 of the drive shaft 6. In this way, the roller 46 provided on the extension piece 45 is rotatable around its own axis.

[0031] The rotational transmission member 42 is gear-shaped with multiple teeth 50. The axial direction J1 of the rotational transmission member 42 is aligned with the axial direction J1 of the drive shaft 6. The rotational transmission member 42 has a circular recess 51 that opens to the other end of the drive shaft 6 in the axial direction J1. Multiple grooves 52 extending in the axial direction J1 of the drive shaft 6 are formed on the inner circumferential surface of the recess 51. The multiple grooves 52 are arranged in the circumferential direction of the inner circumferential surface of the recess 51. A circular through hole 54 penetrating through the axial direction J1 of the drive shaft 6 is formed in the bottom wall 53 of the recess 51.

[0032] The biasing means 43 is a means for biasing the lifting member 41. In the illustrated example, the biasing means 43 has a pressing member 55 and a spring 56. The pressing member 55 is an elongated plate shape with its plate surface oriented perpendicular to the axial direction J1 of the drive shaft 6. The spring 56 is typically a coil spring. In the illustrated example, the biasing means 43 has two springs 56, 56, but is not limited to this, and may have one or three or more.

[0033] The free-spinning mechanism 15 can prevent the rotation of the drive shaft 6 from being transmitted to the lifting member 41. As shown in Figures 3 and 4, the free-spinning mechanism 15 includes the aforementioned rotating drum 11, bearing 57, and spring 58.

[0034] The drum portion 17 of the rotating drum 11 is provided with an annular boss portion 59 at one end of the drum portion 17 in the axial direction J1. The boss portion 59 protrudes from the drum portion 17 to one end of the drum portion 17 in the axial direction J1. The first shaft portion 18 passes through this boss portion 59. Multiple inclined projections 60 are provided on the end face of the boss portion 59, protruding to one end of the drum portion 17 in the axial direction J1. The multiple inclined projections 60 are arranged in the circumferential direction of the annular boss portion 59. The width of each inclined projection 60 decreases as it protrudes in the direction of projection.

[0035] The bearing 57 is cylindrical. The axial direction J1 of the bearing 57 is aligned with the axial direction J1 of the drive shaft 6. One end of the bearing 57 in the axial direction J1 is open, and the other end of the bearing 57 in the axial direction J1 is partially closed by a wall portion 61. The wall portion 61 of the bearing 57 is provided with a circular through hole 62 that penetrates the bearing 57 in the axial direction J1. Multiple inclined projections 63 are provided on the outer surface of the wall portion 61 of the bearing 57, projecting toward the other end of the bearing 57 in the axial direction J1. The multiple inclined projections 63 are arranged in the circumferential direction of the cylindrical bearing 57. The width of each inclined projection 63 decreases as it extends in the direction of projection. Multiple plate-shaped insertion portions 64 are provided on the outer circumferential surface of the bearing 57, projecting radially outward from the bearing 57. The multiple insertion portions 64 are arranged in the circumferential direction of the outer circumferential surface of the cylindrical bearing 57. Spring 58 is typically a coil spring.

[0036] The drum support 16 is a box-shaped structure with an upward opening and is mounted on the headbox 5. As shown in Figure 5, the drum support 16 is provided with a cord guide 65 for the lifting cord 4. The cord guide 65 has a cord insertion hole 66 through which the lifting cord 4 passes. A roller 67 is rotatably mounted inside the cord insertion hole 66. The roller 67 is positioned to span the ends of the cord insertion hole 66. When the roller 67 is positioned inside the cord insertion hole 66, the axis of the roller 67 is aligned with the axial direction J1 of the drive shaft 6. In this way, the roller 67 provided on the cord guide 65 is rotatable about its own axis.

[0037] The rotating drum 11, the winding drum 12, the differential shaft 13, the lifting mechanism 14, and the free-spinning mechanism 15 are arranged within the drum holder 16. In this configuration, the rotating drum 11 and the differential shaft 13 are inserted into the winding drum 12, and the lifting mechanism 14 and the free-spinning mechanism 15 are assembled onto the rotating drum 11.

[0038] When the differential shaft 13 is inserted into the winding drum 12, the flange 31 of the differential shaft 13 abuts against the arc-shaped projection 29 formed on the lifting cord receiver 28 of the winding drum 12. When the differential shaft 13 is inserted into the winding drum 12, the pair of ribs 30, 30 formed on the outer circumferential surface of the differential shaft 13 and the pair of ribs formed on the inner circumferential surface of the winding drum 12 are able to engage with each other. When the rotating drum 11 is inserted into the winding drum 12, the other end of the drum portion 17 in the axial direction J1 abuts against the flange 27 of the winding drum 12. That is, the second shaft portion 19 of the rotating drum 11 is inserted into the winding drum 12. When the second shaft portion 19 of the rotating drum 11 is inserted into the winding drum 12, the pair of projections 23, 23 formed on the rotating drum 11 and the pair of ribs 30, 30 formed on the differential shaft 13 are able to engage with each other. As described above, the pair of ribs 30, 30 of the differential shaft 13 protrude from the end face of the differential shaft 13 toward one end in the axial direction J1 of the differential shaft 13. These protruding portions and the pair of projections 23, 23 of the rotating drum 11 are able to engage with each other.

[0039] With the first shaft portion 18 of the rotating drum 11 passing through the bearing 57, spring 58, rotation transmission member 42, and lifting member 41, the bearing 57, spring 58, rotation transmission member 42, and lifting member 41 are held by the first shaft portion 18 of the rotating drum 11. The bearing 57 is positioned inside the rotation transmission member 42, which is held by the first shaft portion 18, while it is held by the first shaft portion 18 of the rotating drum 11. The bearing 57 is positioned inside the recess 51 of the rotation transmission member 42. At this time, the insertion portion 64 of the bearing 57 is inserted into a groove 52 formed on the inner circumferential surface of the recess 51. With the bearing 57 positioned inside the rotation transmission member 42, the spring 58 is positioned between the bearing 57 and the rotation transmission member 42. One end of the spring 58 abuts against the bottom wall 53 of the recess 51 of the rotation transmission member 42, and the other end of the spring 58 abuts against the wall portion 61 located on the other end side of the bearing 57. When the bearing 57 and the rotation transmission member 42 are held on the first shaft portion 18, the bearing 57 and the rotation transmission member 42 are prevented from falling out of the first shaft portion 18 by an annular retaining ring 68. The retaining ring 68 is locked into the recess 20 of the first shaft portion 18. When the first shaft portion 18 is passed through the insertion hole 47 of the shaft insertion piece 44 of the lifting member 41, the lifting member 41 is held on the first shaft portion 18. In this way, when the bearing 57, spring 58, rotation transmission member 42, and lifting member 41 are held on the first shaft portion 18, the bearing 57 and the rotating drum 11 are engaged with each other. Specifically, the inclined projection 63 formed on the bearing 57 is positioned between the inclined projections 60, 60 formed on the rotating drum 11, and the inclined projection 60 formed on the rotating drum 11 is positioned between the inclined projections 63, 63 formed on the bearing 57.

[0040] The biasing means 43 is provided inside the drum holder 16. With the biasing means 43 provided inside the drum holder 16, a spring 56 is provided between the pressing member 55 and the bottom wall of the drum holder 16. The upper end of the spring 56 is in contact with the pressing member 55, and the lower end of the spring 56 is in contact with the bottom wall of the drum holder 16.

[0041] The rotating drum 11, winding drum 12, differential shaft 13, lifting mechanism 14, and free-spinning mechanism 15 are arranged in the drum support 16 in the assembled state described above. At this time, the drum support 16 supports the first shaft portion 18 of the rotating drum 11 and the portion of the differential shaft 13 that protrudes outward from the flange portion 31. With the lifting member 41 and biasing means 43 arranged in the drum support 16, the pressing member 55 is located below the extended piece 45 of the lifting member 41.

[0042] As mentioned above, a drive shaft 6 passes through the lifting and rotating device 10 with this configuration. The drive shaft 6 passes through the inner hole 69 of the differential shaft 13, the inner hole 70 of the winding drum 12, and the through hole 24 of the rotating drum 11. The drive shaft 6 is a rod-shaped object with a roughly rectangular cross-section. Therefore, the rotating drum 11 can rotate integrally with the drive shaft 6. In this embodiment of the blind 1, the two lifting and rotating devices 10,10 located on the left and right sides of the three lifting and rotating devices 10 have the same configuration. The two lifting and rotating devices 10,10 located on the left and right sides have a different configuration from the centrally located lifting and rotating device 10 mentioned above. The two lifting and rotating devices 10,10 on the left and right sides have a conventionally known configuration and do not have a lifting mechanism 14 and an idler mechanism 15. Specifically, the two left and right lifting and rotating devices 10,10 do not have a bearing 57, a spring 58, a rotation transmission member 42, a retaining ring 68, a lifting member 41, a pressing member 55, or two springs 56,56. The other configurations of the two left and right lifting and rotating devices 10,10 are the same as those of the centrally located lifting and rotating device 10.

[0043] As mentioned above, the lifting cord 4 is connected to the winding drum 12 of the central lifting and rotating device 10 so that it can be wound up and unwound. As shown in Figures 2 and 5, the lifting cord 4 connected to the winding drum 12 passes through the gap formed by the roller 46 and the bifurcated portion of the roller support 49, and then passes through the cord insertion hole 66 of the cord guide 65 to connect to the front side of the bottom rail 26. At this time, the lifting cord 4 is wrapped around the rollers 46 and 67 by the weight of the bottom rail 26. With the lifting cord 4 wrapped around the roller 46, a downward force is applied to the extension piece 45 of the lifting member 41 by the weight of the bottom rail 26. Therefore, the extension piece 45 of the lifting member 41 is biased upward by the biasing means 43.

[0044] In the two left and right lifting and rotating devices 10, 10, the lifting cord 4 is connected to the winding drum 12 so that it can be wound up and unwound. The lifting cord 4 connected to the winding drum 12 is connected to the bottom rail 26 via the drum support 16. At this time, the lifting cord 4 is connected to the rear end of the bottom rail 26 via the ladder holder 25. In the two left and right lifting and rotating devices 10, 10, the ladder cord 2 is connected to the rotating drum 11. Multiple slats 3 are attached to the ladder cord 2 in the same manner as in the case of the centrally located lifting and rotating device 10.

[0045] As shown in Figure 2, in the case of the centrally located lifting and rotating device 10, the lifting mechanism 14 and the free-spinning mechanism 15 are covered by the cover 72 when they are mounted on the drum support 16. Also, the stopper housing 32 provided on the differential shaft 13 is covered by the cover 73. In the case of the two lifting and rotating devices 10, 10 located on the left and right, although not shown, the stopper housings provided on the differential shafts are covered by covers.

[0046] Next, the operation of the blind 1 in this embodiment will be described. As the blind 1 has the configuration described above, by operating one side of the operating cord 9, the drive shaft 6 can be rotated in one direction via the operating unit 7. When the drive shaft 6 rotates in one direction, the pair of protrusions 23, 23 of the rotating drum 11 engage with the pair of ribs 30, 30 of the differential shaft 13, and the pair of ribs 30, 30 of the differential shaft 13 engage with the pair of ribs formed on the inner surface of the winding drum 12, causing the rotating drum 11, differential shaft 13, and winding drum 12 to rotate together. As a result, the lifting cord 4 is wound onto the winding drum 12, allowing the slats 3 and bottom rail 26 to be raised. By raising the slats 3 and bottom rail 26, the blind 1 can be opened.

[0047] The blind 1 can be rotated in the other direction via the operating unit 7 by operating the other end of the operating cord 9 when the slats 3 and bottom rail 26 are in the upper position. The weight of the bottom rail 26 and slats 3 acts on the winding drum 12 via the lifting cord 4, so that a pair of ribs formed on the inner surface of the winding drum 12 engages with a pair of ribs 30, 30 of the differential shaft 13, and a pair of ribs 30, 30 of the differential shaft 13 engages with a pair of protrusions 23, 23 of the rotating drum 11, causing the rotating drum 11, differential shaft 13, and winding drum 12 to rotate as a single unit. As a result, the lifting cord 4 is unwound from the winding drum 12, allowing the slats 3 and bottom rail 26 to be lowered. By lowering the slats 3 and bottom rail 26, the blind 1 can be closed. At this time, the slats 3 lower while closing in the fully closed direction, so when the bottom rail 26 and slats 3 are lowered to their lowest position, the blind is in a fully closed state.

[0048] When the rotation of the drive shaft 6 is stopped midway, the weight of the bottom rail 26 and slats 3 connected to the lifting cord 4 acts on the winding drum 12. As a result, a pair of ribs formed on the inner surface of the winding drum 12 engage with a pair of ribs 30, 30 of the differential shaft 13, and a pair of ribs 30, 30 of the differential shaft 13 engage with a pair of protrusions 23, 23 of the rotating drum 11. Therefore, the rotating drum 11, differential shaft 13, and winding drum 12 stop as a whole. Consequently, the bottom rail 26 and slats 3 are held at the height of the position where the winding drum 12 and other components stop, as described above.

[0049] If the slats 3 and bottom rail 26 hit an obstacle or the like during descent, preventing further descent, the weight of the bottom rail 26 connected to the lifting cord 4 will no longer act on the winding drum 12. If the operation is continued from this state and the drive shaft 6 is further rotated in the slat downward direction, the pair of ribs 30, 30 of the differential shaft 13 will not engage with the pair of protrusions 23, 23 of the rotating drum 11, causing the rotating drum 11 to rotate relative to the differential shaft 13. When the rotating drum 11 rotates relative to the differential shaft 13, after a predetermined amount of rotation, the pair of protrusions 23, 23 of the rotating drum 11 will engage with the pair of ribs 30, 30 of the differential shaft 13, causing the rotating drum 11 and the differential shaft 13 to rotate together. On the other hand, since the pair of ribs 30, 30 of the differential shaft 13 and the pair of ribs formed on the inner surface of the winding drum 12 will not engage, the winding drum 12 will not rotate. In other words, relative rotation occurs between the winding drum 12 and the differential shaft 13.

[0050] When relative rotation occurs between the winding drum 12 and the differential shaft 13, the projection 39 of the stopper 36, located in the stopper housing 32 provided on the differential shaft 13, comes into contact with a projection 29 formed on the lifting cord receiver 28 of the winding drum 12. As a result, the claw portion 38 of the stopper 36 protrudes outward from the stopper housing 32 through the opening 33. When relative rotation occurs between the winding drum 12 and the differential shaft 13, after a predetermined amount of rotation, the pair of ribs 30, 30 of the differential shaft 13 engage with the pair of ribs formed on the inner circumferential surface of the winding drum 12, causing the winding drum 12 to rotate together with the differential shaft 13. As a result, the lifting cord 4 is unwound excessively from the winding drum 12. Then, when the claw portion 38 of the stopper 36 engages with a projection (not shown) provided on the drum receiver 16, further rotation of the differential shaft 13 is restricted, and the rotation of the drive shaft 6 is forcibly stopped.

[0051] When the bottom rail 26 and slats 3 are lowered to their lowest positions, operating the control cord 9 to rotate the drive shaft 6 in the opposite direction to the downward operation causes the rotating drum 11 to rotate in the opposite direction to the downward operation. Since the pair of protrusions 23, 23 on the rotating drum 11 and the pair of ribs 30, 30 on the differential shaft 13 do not engage, the rotating drum 11 rotates relative to the differential shaft 13 by approximately 110 degrees. Since the pair of ribs 30, 30 on the differential shaft 13 and the pair of ribs formed on the inner circumferential surface of the winding drum 12 do not engage, the differential shaft 13 rotates relative to the winding drum 12 by approximately 110 degrees. In other words, the rotating drum 11 can rotate relative to the winding drum 12 by approximately 220 degrees. Within this range, the slats 3 can be angle-adjusted without winding or unwinding the lifting cord 4. During relative rotation, the winding drum 12 may rotate together with the rotating drum 11 due to frictional resistance. In that case, the winding drum 12 may rotate in the direction of winding up the lifting cord 4. As mentioned above, the lifting cord 4 is unwound extra from the winding drum 12. Therefore, even if the lifting cord 4 is wound up, it is possible to prevent the bottom rail 26 and slat 3 from rising.

[0052] As shown in Figure 8(a), when the slats 3 are fully closed, if the lifting cord 4 is excessively unwound from the winding drum 12, the bottom rail 26 will tilt forward. The lifting mechanism 14 can move the bottom rail 26 from the state in Figure 8(a), where it is tilted forward, to the state in Figure 8(b), where it is tilted upward. The operation of the lifting mechanism 14 will be explained using Figures 6(a) to 6(d) and Figures 7(a) to 7(d).

[0053] As shown in Figures 6(a) and 7(a), when the lifting cord 4 is pulled downward by the weight of the bottom rail 26, a downward force is applied to the extension piece 45 of the lifting member 41 due to the weight of the bottom rail 26. Therefore, the extension piece 45 of the lifting member 41 is biased upward by the biasing means 43. In this state, the first shaft portion 18 of the rotating drum 11 is located at the upper end of the insertion hole 47 of the shaft insertion piece 44 of the lifting member 41, and the engaging portion 48 formed on the extension piece 45 of the lifting member 41 is not engaged with the rotation transmission member 42. When the lifting cord 4 is unwound from the winding drum 12 from the state shown in Figures 6(a) and 7(a), as shown in Figures 6(b) and 7(b), at the lowest position, the lifting cord 4 is no longer subjected to the weight of the bottom rail 26 and becomes slack. As a result, the downward force acting on the extension piece 45 of the lifting member 41 is eliminated, and the lifting member 41 moves upward due to the biasing means 43. When the lifting member 41 moves upward, the engaging portion 48 formed on the extension piece 45 of the lifting member 41 engages with the rotation transmission member 42. That is, the engaging portion 48 of the lifting member 41 fits between the adjacent teeth 50, 50 of the rotation transmission member 42. When the lifting member 41 moves upward, the first shaft portion 18 of the rotation drum 11 is positioned at the lower end of the insertion hole 47 of the shaft insertion piece 44 of the lifting member 41.

[0054] As described above, the inclined projection 60 of the rotating drum 11 and the inclined projection 63 of the bearing 57 located inside the rotation transmission member 42 are engaged, so the rotation transmission member 42 can rotate together with the rotating drum 11. Therefore, when the winding drum 12 is rotating in the direction of unwinding the lifting cord 4 by the rotating drum 11, which is rotated by the drive shaft 6, the rotation transmission member 42 is also rotated by the rotating drum 11 in the direction of unwinding the lifting cord 4 from the winding drum 12. As the rotation transmission member 42 rotates in this way, the engaging portion 48 of the lifting member 41 is engaged with the rotation transmission member 42, so as shown in Figures 6(c) and 7(c), the lifting member 41 rotates together with the rotation transmission member 42 in the direction of unwinding the lifting cord 4 from the winding drum 12. Subsequently, as shown in Figures 6(d) and 7(d), when the lifting member 41 rotates, the extended piece 45 of the lifting member 41 comes into contact with the restricting portion 71 formed in the drum receiver 16.

[0055] In this way, the lifting mechanism 14 moves the lifting member 41 from a first position where the rotation of the drive shaft 6 cannot be transmitted to a second position where the rotation of the drive shaft 6 can be transmitted. The movement of the lifting member 41 is performed by a biasing means 43. The biasing means 43 biases the lifting member 41 from the first position to the second position. After the lifting member 41 has moved, the lifting mechanism 14 can operate the lifting member 41 located at the second position to pull up the slackened lifting cord 4 by the rotation of the drive shaft 6 in the slat downward direction. At this time, as described above, a rotation transmission member 42 is used which is provided so as to be rotatable integrally with the drive shaft 6 and capable of transmitting the rotation of the drive shaft 6 to the lifting member 41 located at the second position. When the lifting member 41 rotates, the lifting cord 4 is pulled up by the lifting member 41 because it is wrapped around the roller 46 of the lifting member 41. By pulling up the lifting cord 4, the front end of the bottom rail 26 can be pulled upward. Therefore, by pulling up the lifting cord 4 with the lifting mechanism 14, the bottom rail 26 can be tilted upward.

[0056] When the bottom rail 26 tilts upward, as shown in Figure 8(b), the slats 3 located directly above the bottom rail 26 are pushed by the tilting bottom rail 26, causing multiple slats 3 in the vicinity of the bottom rail 26 to tilt almost vertically. Note that the slats 3 do not necessarily have to be directly pushed by the bottom rail 26 when the bottom rail 26 tilts upward. When the bottom rail 26 tilts upward, the downward pull on the ladder cord 2 is eliminated, causing the slats 3 in the vicinity of the bottom rail 26 to tilt upward.

[0057] When the extension piece 45 of the lifting member 41 is in contact with the restricting portion 71, even if the rotating drum 11 rotates further in the direction of unwinding the lifting cord 4, the rotation of the rotating drum 11 is not transmitted to the rotation transmission member 42 by the free-spinning mechanism 15, and the rotation transmission member 42 stops rotating. As mentioned above, a spring 58 made of a coil spring is arranged between the bearing 57, which can engage with the rotating drum 11, and the rotation transmission member 42. Also, the inclined projections 60 and 63 become narrower in width as they protrude. Therefore, when the rotating drum 11 is rotated by the drive shaft 6 while the extension piece 45 of the lifting member 41 is in contact with the restricting portion 71, the engagement between the rotating drum 11 and the bearing 57 is not maintained, and the rotation of the rotating drum 11 is not transmitted to the rotation transmission member 42. As a result, even if the rotating drum 11 rotates, the rotation transmission member 42 does not rotate.

[0058] The restricting portion 71, which the extended piece 45 of the lifting member 41 abuts against, is provided on the drum support 16. The drum support 16 has the function of supporting the rotating drum 11, the winding drum 12, the differential shaft 13, the lifting mechanism 14, and the free-spinning mechanism 15, and also functions as a restricting means to restrict the rotation of the lifting member 41 beyond a predetermined amount. When the rotation of the lifting member 41 is restricted by the restricting means and the drive shaft 6 rotates in the slat downward direction with a torque exceeding a predetermined amount, the rotation from the rotating drum 11 is not transmitted to the rotation transmission member 42. Therefore, the free-spinning mechanism 15 can be operated to prevent the transmission of rotation input from the drive shaft 6 to the lifting member 41.

[0059] In the case of the blind 1 of this embodiment, the lifting cord 4, which is connected to the centrally located lifting and rotating device 10, is wrapped around the roller 46 of the lifting member 41 from above. Therefore, the lifting member 41 is provided with a lifting cord 4 that is connected to the front side of the bottom rail 26 and can be lifted up when the slat 3 is in the fully closed state. In the case of the blind 1 of this embodiment, as described above, the lifting mechanism 14 can lift up the lifting cord 4 connected to the centrally located lifting and rotating device 10. The lifting mechanism 14 can automatically lift up the lifting cord 4 when the lifting cord 4 becomes loose due to the drive shaft 6 rotating in the downward direction of the slat at the upper limit position of the slat 3.

[0060] Therefore, according to the blind 1 of this embodiment, when the slats 3 are lowered to their maximum height and closed position, the excess unwinding and slackening lifting cord 4 is pulled up, raising the bottom rail 26. This causes the slats 3 near the bottom rail 26 to tilt more vertically, improving the shielding performance in the fully closed state (especially the shielding performance near the bottom rail 26). In other words, the shielding performance in the fully closed state can be improved by pulling up the lifting cord 4 connected to the end of the bottom rail 26 without providing a new cord to tilt the slats 3 more vertically. Furthermore, this also has the effect of preventing the slackening lifting cord 4 from hanging down from support members such as the headbox 5 and impairing the aesthetic appearance.

[0061] In the case of the blind 1 of this embodiment, a slackening lifting cord 4 is routed around a portion of the lifting member 41, and the slackened lifting cord 4 can be lifted by rotating integrally with the rotation transmission member 42. Therefore, in the blind 1 of this embodiment, since the lifting member 41 rotates to lift the slackened lifting cord 4, it is easy to increase the travel distance of the lifting member 41 to lift the slack portion of the lifting cord 4. For this reason, the lifting mechanism 14 can be made smaller compared to a configuration in which, for example, the lifting member 41 moves upward to lift the slackened lifting cord 4.

[0062] In the case of the blind 1 of this embodiment, the lifting member 41 is held in the first position by the tension of the slacken lifting cord 4, which is routed to a portion of the lifting member 41, when the slacken lifting cord 4 is in a taut state, and can be moved to the second position by the biasing force of the biasing means 43 when the slacken lifting cord 4 becomes slack. Therefore, according to the blind 1 of this embodiment, the lifting mechanism 14 is not operated when the lifting cord 4 is in a taut state (i.e., when the load of the bottom rail 26 and slat 3 is applied to the lifting cord 4 at an intermediate lifting position), and the lifting mechanism 14 is reliably switched to operate only when the lifting cord 4 becomes slack.

[0063] In the case of the blind 1 of this embodiment, the blind 1 has a free-spinning mechanism 15 that operates when the lifting member 41 comes into contact with the restricting part 71. Therefore, with the blind 1 of this embodiment, even if a large torque is input to the drive shaft 6 while the rotation of the lifting member 41 is restricted, the free-spinning mechanism 15 prevents damage to the parts.

[0064] It should be noted that the present invention is not limited to the embodiments described above, and any modifications or improvements that can achieve the objectives of the present invention are included within the scope of the present invention.

[0065] In the above embodiment, the lifting cord 4 that allows the bottom rail 26 to be tilted upward is connected to the front side of the bottom rail 26, but is not limited to this, and may also be connected to the rear side of the bottom rail 26. The lifting cord 4 that allows the bottom rail 26 to be tilted upward is not limited to being connected to the front side or the rear side of the bottom rail 26, but is only required to be connected to the bottom rail 26 in such a way that the bottom rail 26 can be tilted upward. That is, the lifting member 41 is provided with a lifting cord 4 among a plurality of lifting cords 4 that is connected to the bottom rail 26 and allows the bottom rail 26 to be tilted upward when the slats 3 are fully closed, so that it can be lifted up. [Explanation of Symbols]

[0066] 1 Blind 2 Ladder Code 3 Slats 4. Lifting cord 6 drive shafts 14 Lifting mechanism 15. Slip Mechanism 16 Drum receiver (regulating means) 26 Bottom Rail 41 Lifting member 42 Rotation transmission member 43. Biasing means

Claims

1. A blind having multiple lifting cords that allow multiple slats to be raised and lowered, which are tiltably supported by ladder cords, A blind comprising a lifting mechanism that includes a lifting member provided to pull up one of the plurality of lifting cords, which is connected to the bottom rail and can be relaxed when the slat is fully closed, and when the lifting cord becomes relaxed as the drive shaft rotates in the downward direction of the slat at the upper limit position of the slat, the lifting member moves from a first position where the rotation of the drive shaft cannot be transmitted to a second position where the rotation of the drive shaft can be transmitted, and the lifting member located at the second position is operated to pull up the relaxed lifting cord as the drive shaft rotates in the downward direction of the slat, thereby tilting the bottom rail upward.

2. The lifting mechanism further includes a rotation transmission member that is rotatably mounted integrally with the drive shaft and capable of transmitting the rotation of the drive shaft to the lifting member located at the second position. The blind according to claim 1, wherein the lifting member has a slacken lifting cord routed around a part of it, and rotates integrally with the rotation transmission member to lift the slackened lifting cord.

3. The lifting mechanism further includes a biasing means for biasing the lifting member from the first position toward the second position, The blind according to claim 1, wherein the lifting member is held in the first position by the tension of the slacken lifting cord routed to a portion thereof when the slacken lifting cord is in a taut state, and moves to the second position by the biasing force of the biasing means when the slacken lifting cord becomes slack.

4. A restricting means for restricting the rotation of the lifting member beyond a predetermined amount, The blind according to claim 2, further comprising: an idle mechanism that, when the rotation of the lifting member is restricted by the restricting means, the drive shaft rotates in the slat downward direction with a torque exceeding a predetermined value, and the drive shaft rotates in the slat downward direction, the idle mechanism that prevents the rotation input from the drive shaft from being transmitted to the lifting member.

5. The blind according to claim 1, wherein the slacken lifting cord is connected to the front or rear of the bottom rail.

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