Sheet shutter

Abstract

To provide a sheet shutter capable of preventing adjacent engaging elements from interfering with each other when a sheet curtain bends in an opposite direction to a curvature direction during moving along a circumferential direction of a gear member.SOLUTION: A sheet shutter includes:a plurality of engaging elements that are attached to side end portions on both ends of the sheet curtain; and gear members that rotate forward and backward in a state engaged with the engaging elements to move the sheet curtain along a gear circumference to thereby wind or unwind the sheet curtain onto or from a winding roll. In the engaged state, each of the plurality of engaging elements: has a pair of side surfaces that face in the gear circumferential direction and are in contact with each other; a top surface facing radially outward of the gear member in the engaged state; and a flat or curved inclined surface from each of the pair of side surfaces to the top surface. Assuming that a radial dimension from an attachment center of the engaging element to the sheet curtain to the top surface is LA and a dimension from the attachment center to an intersection of the side surface and the inclined surface is LB, LA / 2≥LB.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to a sheet shutter.

Background Art

[0002] Patent Document 1 discloses a sheet shutter having a frame composed of an upper frame and side frames, a rotating shaft rotatably provided in the upper frame and connected to drive means, a sheet suspended from the rotating shaft so as to be freely wound and unwound, and a plurality of guide blocks provided at both left and right ends of the sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a sheet shutter, for example, a sheet curtain wound around a winding roll, a plurality of engaging members attached to both side end portions of the sheet curtain along the winding direction by the winding roll, and a forward and reverse rotation in an engaged state with the engaging members to move the sheet curtain along the circumferential direction of the gear, so that the sheet curtain is wound around or unwound from the winding roll to move the sheet curtain up and down. A configuration including a gear member is conceivable.

[0005] In this configuration, when an object is sandwiched between the sheet curtains of the sheet shutter and the sheet curtain is bent, it is conceivable that adjacent engaging members interfere with each other and the engaging members and the sheet curtain are damaged.

[0006] In particular, when the sheet curtain bends in the direction opposite to the direction in which it bends when moving along the circumferential direction of the gear member, adjacent engaging elements are likely to interfere with each other, and the engaging elements and the sheet curtain are likely to be damaged.

[0007] An object of the present disclosure is to suppress interference between adjacent engaging elements when the sheet curtain bends in the direction opposite to the direction in which it bends when moving along the circumferential direction of the gear member.

Means for Solving the Problems

[0008] The sheet shutter according to the first aspect includes a sheet curtain wound around a winding roll, a plurality of engaging elements attached to both side end portions of the sheet curtain along the winding direction by the winding roll, and an engaging state engaged with the engaging elements. A gear member that rotates forward and backward to move the sheet curtain along the circumferential direction of the gear, thereby winding or unwinding the sheet curtain around the winding roll and moving the sheet curtain up and down. Each of the plurality of engaging elements faces the circumferential direction of the gear in the engaged state, has a pair of side surfaces that contact each other, a top surface that faces the outside in the radial direction of the gear member in the engaged state, and from each of the pair of side surfaces to the top surface. It has an inclined surface that is inclined in a planar or curved shape. When the dimension along the radial direction from the attachment center of the engaging element to the top surface with respect to the sheet curtain is LA, and the dimension along the radial direction from the attachment center to the intersection of the side surface and the inclined surface is LB, LA / 2≧LB.

[0009] According to the above configuration, the gear member rotates forward and backward in the engaged state with the engaging element, and moves the sheet curtain along the circumferential direction of the gear, thereby winding or unwinding the sheet curtain around the winding roll and moving the sheet curtain up and down.

[0010] Furthermore, each of the plurality of engaging elements has, in the engaged state, a pair of side surfaces facing the circumferential direction of the gear and contacting each other, a top surface facing radially outward of the gear member in the engaged state, and inclined surfaces that are inclined in a planar or curved shape from each of the pair of side surfaces to the top surface.

[0011] When the dimension along the radial direction from the attachment center of the engaging element to the top surface is defined as LA, and the dimension along the radial direction from the attachment center to the intersection of the side surface and the inclined surface is defined as LB, LA / 2 ≧ LB.

[0012] Therefore, compared with the case where LA / 2 < LB, the edge formed by the side surface and the curved surface is located closer to the attachment center side than the top surface.

[0013] As a result, even when the seat curtain bends in the direction opposite to the direction in which it curves when moving along the circumferential direction of the gear member, compared with the case where LA / 2 < LB, the edges of adjacent engaging elements are less likely to get caught, and interference between the engaging elements is suppressed. As a result, damage to the engaging elements and the seat curtain is suppressed.

[0014] In the seat shutter according to the second aspect, in the first aspect, each of the plurality of engaging elements is formed symmetrically with respect to a center line along the radial direction passing through the attachment center when viewed along the axial direction of the gear member, and is formed symmetrically with respect to an orthogonal line passing through the attachment center and perpendicular to the center line.

[0015] According to the above configuration, each of the plurality of engaging elements is formed symmetrically with respect to the center line and symmetrically with respect to the orthogonal line. Therefore, for example, it is possible to use the engaging element by inverting it with respect to the center line. For this reason, it is possible to attach the engaging element to the seat curtain without checking the orientation of the engaging element, and the manufacturing process and manufacturing equipment can be simplified.

[0016] In the sheet shutter according to the third aspect, in the first aspect or the second aspect, the gear member has a plurality of engaging recesses formed side by side in the circumferential direction of the gear, and the engaging state is achieved by the engaging recesses engaging with the engaging elements. In the engaging recesses, a pair of side planes facing each other in the circumferential direction of the gear and a bottom surface sandwiched between the pair of side planes are formed. In the engaging elements, a pair of engaging planes that are in surface contact with the side planes and a contact surface that contacts the bottom surface are formed.

[0017] According to the above configuration, in the engaging recesses, a pair of side planes facing each other in the circumferential direction and a bottom surface sandwiched between the pair of side planes are formed. Further, in the engaging elements, an engaging plane that is in surface contact with the pair of side planes and a contact surface that contacts the bottom surface are formed.

[0018] As a result, when the gear member rotates, the side plane of the engaging recess is in surface contact with the engaging plane of the engaging element, and the force is transmitted from the rotating gear member to the engaging element. Therefore, compared with the case where the engaging recess of the gear member and the engaging element are in contact with each other on an arc surface, the movement of the engaging element in the circumferential direction of the arc surface is suppressed, so that the posture of the engaging element with respect to the gear member can be stabilized.

[0019] In the sheet shutter according to the fourth aspect, in the third aspect, when viewed from the axial direction of the gear member, the angle formed by a reference line passing through the outermost point in the radial direction of the gear member and the axial center point of the gear member in the side plane and a straight line extending along the side plane is smaller than the angle formed by the reference line and the tangent line at the outermost point of the arc surface when the engaging recess is an arc surface that contacts the bottom surface and passes through the outermost point.

[0020] According to the above configuration, the angle formed by the reference line passing through the outermost point of the side plane and the axial center point of the gear member and the straight line extending along the side plane is smaller than the angle formed by the reference line and the tangent line at the outermost point of the arc surface.

[0021] Therefore, among the forces exerted on the engaging element by the rotating gear member, the force acting in the circumferential direction of the gear member becomes stronger compared to the case where the engaging recess is an arcuate surface. In other words, compared to the case where the engaging recess is an arcuate surface, the force attempting to move the engaging element in the circumferential direction of the gear member can be efficiently transmitted from the gear member to the engaging element.

[0022] In the sheet shutter according to the fifth aspect, in the fourth aspect, as viewed from the axial direction of the gear member, a contact block that is disposed on the opposite side of the gear member with the engaging element interposed therebetween and that comes into contact with the engaging element when the engaging element engaged with the engaging recess moves outward in the radial direction of the gear member is provided.

[0023] According to the above configuration, the contact block disposed on the opposite side of the gear member with the engaging element interposed therebetween comes into contact when the engaging element engaged with the engaging recess moves outward in the radial direction of the gear member, and restricts the movement of the engaging element in the radial direction of the gear member.

[0024] Here, the angle formed by the reference line passing through the outermost point of the side plane and the axial center point of the gear member and the straight line extending along the side plane is smaller than the angle formed by the reference line and the tangent line at the outermost point of the arcuate surface. Therefore, among the forces exerted on the engaging element by the rotating gear member, the force acting in the radial direction of the gear member becomes weaker compared to the case where the engaging recess is an arcuate surface. In other words, compared to the case where the engaging recess is an arcuate surface, the frictional force generated between the engaging element and the contact block can be weakened.

[0025] In the sheet shutter according to the sixth aspect, in any one of the aspects described in the third aspect to the fifth aspect, in a state where the engaging element is engaged with the engaging recess and the sheet curtain is moved up and down, one of the side planes and one of the engaging planes are in surface contact, and the other side plane and the other engaging plane are separated from each other.

[0026] According to the above configuration, in a state where the engaging member is engaged with the engaging recess and the sheet curtain is moved up and down, one side plane and one engaging plane are in surface contact, and the other side plane and the other engaging plane are separated. Therefore, when the gear member rotates and engages the engaging member approaching from the tangential direction with the engaging recess, it is possible to suppress interference between the contact surface of the engaging member and the outer peripheral surface of the gear member.

[0027] In the sheet shutter according to the seventh aspect, in the aspect according to any one of the third aspect to the sixth aspect, in a state where the engaging member is engaged with the engaging recess and the sheet curtain is moved up and down, the contact surface formed on the engaging member is in surface contact with the bottom surface formed in the engaging recess.

[0028] According to the above configuration, in a state where the engaging member is engaged with the engaging recess and the sheet curtain is moved up and down, the contact surface formed on the engaging member is in surface contact with the bottom surface formed in the engaging recess. Therefore, compared with the case where the contact surface formed on the engaging member is in point contact with the bottom surface formed in the engaging recess, the posture of the engaging member with respect to the gear member can be stabilized.

Effect of the Invention

[0029] Since the present disclosure has the above configuration, when the sheet curtain bends in a direction opposite to the direction in which it bends when moving along the circumferential direction of the gear member, interference between adjacent engaging members can be suppressed, which has an excellent effect.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

MODE FOR CARRYING OUT THE INVENTION

[0031] Hereinafter, an example of an embodiment according to the present invention will be described with reference to the drawings.

[0032] (Seat shutter 10) First, the configuration of the seat shutter 10 according to the present embodiment will be described. FIG. 1 is a perspective view showing the schematic configuration of the seat shutter 10 according to the present embodiment.

[0033] Note that the arrow UP in each figure including FIG. 1 indicates the upper side (specifically, vertically upward) of the sheet shutter 10. Hereinafter, the direction indicated by the arrow LH in each figure including FIG. 1 is defined as the left side of the sheet shutter 10, and the opposite direction of the direction indicated by the arrow LH is defined as the right side of the sheet shutter 10 for explanation. Also, the direction indicated by the arrow RR in each figure including FIG. 1 is defined as the rear side of the sheet shutter 10, and the opposite direction of the direction indicated by the arrow RR is defined as the front side of the sheet shutter 10 for explanation.

[0034] Further, when the left - right direction of the sheet shutter 10 is referred to as the "shutter width direction", and when the front - rear direction of the sheet shutter 10 is referred to as the "shutter depth direction". Note that the above - mentioned left side, right side, front side, and rear side are directions defined for convenience of explanation, so the configuration of the sheet shutter 10 is not limited to these directions.

[0035] The sheet shutter 10 shown in FIG. 1 is, for example, applied to the loading entrance 102 (an example of an opening) of a room such as a freezer, a refrigerator, and a warehouse, and is a shutter capable of opening and closing the loading entrance 102. Note that in FIG. 1, the sheet shutter 10 in the state of closing the loading entrance 102 is shown. Hereinafter, closing the loading entrance 102 may be referred to as "closing", and opening the loading entrance 102 may be referred to as "opening".

[0036] The sheet shutter 10 may be applied to the entrance and exit of a building, the opening of a window, etc., and can be applied to an opening to be opened and closed. Specifically, the opening to which the sheet shutter 10 is applied is formed in a side wall of a structure or the like and is an opening that opens laterally (sideways).

[0037] In the present embodiment, the sheet shutter 10 is configured symmetrically with respect to the center line CL11 of the sheet shutter 10 in the shutter width direction. That is, the sheet shutter 10 is configured symmetrically left - and - right.

[0038] Specifically, as shown in FIG. 1, the sheet shutter 10 includes a frame 12, a curtain unit 30 having a sheet curtain 32, a winding roll 20, and a driving roll 60. Further, as shown in FIG. 2, the sheet shutter 10 includes a gear member 64 and a contact block 80. Hereinafter, the configuration of each part of the sheet shutter 10 will be described.

[0039] (Frame 12) As shown in FIG. 1, the frame 12 includes a pair of side frames 22, a shutter case 18, and a pair of guide rails 14 (see FIG. 2). The pair of side frames 22 extend along the vertical direction on the left and right sides with respect to the loading entrance 102. The pair of side frames 22 have their rear surfaces 22B fixed, for example, to the wall surfaces (not shown) of the side edges on the left and right sides with respect to the loading entrance 102.

[0040] The side frame 22 has a U-shaped cross section that is cut in a direction perpendicular to its longitudinal direction and has an opening on the inner side in the shutter width direction (that is, the side closer to the center line CL11 in the shutter width direction of the sheet shutter 10) (see FIGS. 2 and 6).

[0041] As shown in FIG. 2, each of the pair of guide rails 14 is disposed inside each of the pair of side frames 22 along the vertical direction. The guide rail 14 has a U-shaped cross section that is cut in a direction perpendicular to its longitudinal direction and has an opening on the inner side in the shutter width direction. Further, a pair of flange portions 16 are formed on the inner side portion of the guide rail 14 in the shutter width direction so as to narrow the opening width (see FIG. 6). Also, the upper ends of the guide rail 14 and the side frame 22 are open upward.

[0042] Inside the guide rail 14, a plurality of engaging elements 40 (described later) provided in the curtain unit 30 are inserted so as to be movable in the vertical direction. The pair of guide rails 14 guide the plurality of engaging elements 40 in the vertical direction so that the curtain unit 30 (specifically, the sheet curtain 32) moves in the vertical direction.

[0043] As shown in FIG. 1, the shutter case 18 is arranged along the shutter width direction so as to connect the upper ends of a pair of side frames 22. This shutter case 18 projects forward with respect to the pair of side frames 22. In the present embodiment, the rear surface 18B of the shutter case 18 is fixed to, for example, the wall surface (not shown) of the upper edge of the loading entrance 102.

[0044] Furthermore, the shutter case 18 is formed in a box shape, and the inside of the shutter case 18 is hollow. The inside of the shutter case 18 communicates with the inside of the pair of side frames 22 and the inside of the pair of guide rails 14 through the openings at the upper ends of the pair of side frames 22 and the upper ends of the pair of guide rails 14.

[0045] (Take-up roll 20) The take-up roll 20 shown in FIG. 2 is a roll for winding up the sheet curtain 32. As shown in FIG. 2, this take-up roll 20 is arranged along the shutter width direction on the front side inside the shutter case 18. Further, the take-up roll 20 is rotatably supported with respect to a support portion (not shown) such as a side plate arranged inside the shutter case 18, with the shutter width direction as the axial direction. Furthermore, one end of the sheet curtain 32 is attached to the take-up roll 20. The one end is the upper end in a state where the sheet curtain 32 closes the loading entrance 102 (hereinafter referred to as the "closed state").

[0046] Then, the take-up roll 20 is biased by a biasing member (not shown) so as to rotate in the direction of winding up the sheet curtain 32 (hereinafter referred to as the "take-up direction"). As a result, a force in the take-up direction (specifically, upward) acts on the sheet curtain 32 by the take-up roll 20.

[0047] (Curtain unit 30) The curtain unit 30 shown in Fig. 1 has a function as an opening / closing part that can open and close the loading entrance 102. Specifically, as shown in Fig. 2, the curtain unit 30 has a sheet curtain 32, a pair of wires 36 (see Fig. 9), and a plurality of engaging elements 40. Hereinafter, the configuration of each part of the curtain unit 30 will be described.

[0048] (Sheet curtain 32 and wire 36) The sheet curtain 32 shown in Fig. 2 functions as an opening / closing part that can open and close the loading entrance 102 by moving vertically below the drive roll 60 and the gear member 64. Hereinafter, the moving direction of the sheet curtain 32 will be referred to as the "sheet moving direction".

[0049] The sheet curtain 32 is formed in a rectangular shape having a length in the winding direction (i.e., the sheet moving direction). As described above, one end in the longitudinal direction is attached to the winding roll 20. In the state of being unwound from the winding roll 20, this sheet curtain 32 hangs down due to its own weight and closes the loading entrance 102. In the closed state, the sheet curtain 32 is disposed between the pair of side frames 22 as shown in Fig. 1.

[0050] Furthermore, the sheet curtain 32 is formed in a sheet shape in which the depth direction of the shutter in the closed state is the thickness direction. This sheet curtain 32 is formed of, for example, a resin material and has flexibility that can be deformed into a roll shape along the outer periphery of the winding roll 20 around which it is wound. Note that as long as the sheet curtain 32 has such flexibility, the material of the sheet curtain 32 is not limited to the resin material, and various materials can be used.

[0051] In addition, the side end portions on both sides of the sheet curtain 32 are specifically folded back as shown in FIGS. 6 and 9. In other words, the sheet curtain 32 has folded-back portions 35 where the side end portions on both sides are folded back. In the folded-back portions 35, the folded-back side end portions are fused to other portions that overlap in the sheet curtain 32. As a result, a cavity portion 32a is formed in the side end portion (i.e., the folded-back portion 35) of the sheet curtain 32. Note that FIGS. 6 and 9 show the right-end side portion of the sheet curtain 32, but the left-end side portion of the sheet curtain 32 is configured in the same manner.

[0052] The wire 36 is an example of a reinforcing member and is disposed in the cavity portion 32a. Therefore, the wire 36 is provided at each of the side end portions on both sides of the sheet curtain 32. This wire 36 is formed by twisting a plurality of elementary wires such as steel wires. In this way, since the wire 36 is disposed in the cavity portion 32a, the side end portions on both sides of the sheet curtain 32 bulge in the thickness direction of the sheet curtain 32 as compared with other portions.

[0053] An example of the reinforcing member is not limited to the wire 36 and may be formed of a resin material, and various materials and shapes can be used.

[0054] (Engaging element 40, screw 38) The engaging element 40 is attached to the side end portions (i.e., the folded-back portions 35) on both sides of the sheet curtain 32 and is arranged in a plurality in the moving direction of the sheet curtain 32 as shown in FIGS. 3 and 9. In other words, the engaging elements 40 are arranged in a plurality in the winding direction of the sheet curtain 32. Note that FIGS. 3 and 9 show the right-end side portion of the sheet curtain 32, but the left-end side portion of the sheet curtain 32 is configured in the same manner.

[0055] The engaging element 40 is integrally formed using a resin material (in this embodiment, polyacetal (POM)). Further, as shown in FIGS. 6 and 7(A), with the engaging element 40 disposed inside the guide rail 14, when viewed from above, the engaging element 40 has a rectangular shape with a U-shaped groove portion 42 formed such that the inner side in the shutter width direction is open. Further, protrusions 44 are respectively formed at the open ends of the groove portion 42. Note that FIGS. 6 and 7(A) show the engaging element 40 disposed at the right end side portion of the sheet curtain 32, but the engaging element 40 disposed at the left end side portion of the sheet curtain 32 is similarly configured.

[0056] In the inner side portion of the groove portion 42 in the shutter width direction, when viewed from above, a gradually changing portion 42a is formed where the opening width gradually widens toward the inner side in the shutter width direction. Further, in the outer side portion of the groove portion 42 in the shutter width direction (the side away from the center line CL11 of the sheet shutter 10 in the shutter width direction), when viewed from above, an elliptical circular portion 42b with a widened opening width is formed. Both end side portions of the sheet curtain 32 that are swollen by the wire 36 in the shutter width direction are disposed in this circular portion 42b (see FIG. 6).

[0057] Further, the engaging element 40 is formed with a side surface 40a facing the outer side in the shutter width direction and a through hole 46 with a circular cross-section that penetrates from the side surface 40a to the circular portion 42b of the groove portion 42. In the outer side portion of this through hole 46 in the shutter width direction, a diameter expanding portion 46a is formed where the diameter dimension gradually widens toward the outer side in the shutter width direction. As shown in FIGS. 8 and 9, a screw 38 is inserted into this through hole 46 from the outer side in the shutter width direction, and the tip side portion of the screw 38 is twisted into the wire 36, whereby the engaging element 40 is attached to the side end portions on both sides of the sheet curtain 32 (see FIGS. 6 and 9).

[0058] Furthermore, as shown in FIGS. 5 and 7(B), the engaging element 40 is formed with a contact portion 50 that contacts the contact block 80 and an engaging portion 54 that engages with the engaging recess 66 of the gear member 64 provided on the drive roll 60. The specific configuration of the engaging element 40 including the contact portion 50 and the engaging portion 54 (such as the shape of the engaging element 40) will be described later.

[0059] The screw 38 is a dish-shaped tapping screw. As shown in FIG. 6, with the tip side portion of the screw 38 being twisted into the wire 36, the head of the screw 38 is disposed in the enlarged diameter portion 46a of the through hole 46. Thereby, the head of the screw 38 is received in the enlarged diameter portion 46a of the through hole 46 and does not protrude from the side surface 40a of the engaging element 40.

[0060] It is desirable that the attachment of the engaging element 40 to the sheet curtain 32 be performed while managing the pitch 40P (see FIG. 5) of the engaging element 40 using equipment such as an attachment jig or an attachment device. In this equipment, by attaching to the sheet curtain 32 with the engaging element 40 positioned, it is possible to make the pitch 40P of the engaging element 40 constant and a preset dimension. As a result, when the sheet curtain 32 is wound around the winding roll 20, etc., the plurality of engaging elements 40 are likely to bend between the engaging elements 40, reducing the load on the engaging elements 40 and the sheet curtain 32 and suppressing damage to the engaging elements 40 and the sheet curtain 32. When the width 40N (see FIG. 5) of the engaging element 40 is, for example, 12.9 mm, the pitch 40P (see FIG. 5) is set in a range of, for example, 12.98 mm or more and 13.00 mm or less. Note that the attachment of the engaging element 40 to the sheet curtain 32 may be performed manually.

[0061] (Drive Roll 60 and Gear Member 64) As shown in FIG. 2, the drive roll 60 is disposed on the rear side inside the shutter case 18 and above the pair of guide rails 14 along the shutter width direction. Further, the drive roll 60 is rotatably supported with respect to a support portion (not shown) such as a side plate disposed inside the shutter case 18 with the shutter width direction as the axial direction. A part of the sheet curtain 32 is wound around the drive roll 60 and is curved along the circumferential direction of the drive roll 60. Note that the drive roll 60 may be supported by the support portion that supports the take-up roll 20 or may be supported by another support portion.

[0062] As shown in FIG. 2, the pair of gear members 64 are disposed at one end side and the other end side in the axial direction of the drive roll 60, respectively. The gear member 64 is made of, for example, metal. As shown in FIGS. 3 and 4, a plurality of engagement recesses 66 with which the engagement portions 54 of the engagee 40 engage are formed side by side in the circumferential direction on the outer periphery of the gear member 64. The specific configuration of the engagement recess 66 of the gear member 64 will be described later.

[0063] Further, as shown in FIG. 3, a flange 68 protruding radially outward is formed outside the gear member 64 in the shutter width direction. This flange 68 restricts the movement of the sheet curtain 32 including the engagee 40 outward in the shutter width direction. Furthermore, the drive roll 60 and the gear member 64 are configured to be capable of normal rotation (K01 direction) and reverse rotation (K02 direction) by a motor (not shown). In the present embodiment, the gear member 64 rotates forward and backward in an engaged state with the engagee 40, and moves the sheet curtain 32 along the circumferential direction of the gear member 64, thereby winding or unwinding the sheet curtain 32 around the take-up roll 20 and moving the sheet curtain 32 up and down.

[0064] The gear member 64 is specifically fixed to a shaft (not shown) provided on a core (not shown) that rotates by a motor (not shown) by fitting and fastening. Thereby, the axis center of the shaft and the axis center of the gear member 64 can be made to coincide, and eccentricity of the gear member 64 can be suppressed.

[0065] (Contact block 80) A pair of contact blocks 80 are provided and are respectively arranged on the rear side and the left and right sides inside the shutter case 18 as shown in FIG. 2. Specifically, as shown in FIGS. 3 and 4, the contact blocks 80 are arranged on the opposite side of the gear member 64 with a plurality of engaging elements 40 interposed therebetween.

[0066] The contact block 80 is formed in an arc shape using a metal material (in this embodiment, for example, made of zinc die-cast) and is supported by a support portion (not shown) such as a side plate arranged inside the shutter case 18. And the contact block 80 has an inner peripheral surface 80a facing the gear member 64 side. Note that the contact block 80 may be supported by a support portion that supports at least one of the winding roll 20 and the drive roll 60, or may be supported by another support portion.

[0067] When a plurality of engaging elements 40 that mesh with the engaging recess 66 of the gear member 64 move radially outward of the gear member 64, the inner peripheral surface 80a of the contact block 80 contacts the engaging elements 40 and restricts the movement of the engaging elements 40. Thereby, the meshing state between the engaging recess 66 of the gear member 64 and the engaging elements 40 is maintained.

[0068] (Opening and closing operation of the sheet shutter 10) With the loading entrance 102 blocked by the curtain unit 30 (specifically, the sheet curtain 32), when the drive roll 60 and the gear member 64 rotate in the forward direction (the K01 direction shown in FIG. 4) by a motor (not shown), the rotating gear member 64 sequentially engages the engaging elements 40 approaching from the tangential direction (F01 in the figure) with the engaging recesses 66. Further, the rotating gear member 64 sequentially disengages the engaging elements 40 that were engaged with the engaging recesses 66, and the disengaged engaging elements 40 move away in the tangential direction (F02 in the figure).

[0069] As a result, the sheet curtain 32 moves upward while being guided by the pair of guide rails 14, opening the loading entrance 102. At this time, the winding roll 20 biased in the winding direction by a biasing member (not shown) winds up the sheet curtain 32.

[0070] With the loading entrance 102 opened by the sheet curtain 32, when the drive roll 60 and the gear member 64 rotate in the reverse direction (the K02 direction shown in FIG. 4) by a motor (not shown), the rotating gear member 64 sequentially engages the engaging elements 40 approaching from the tangential direction (F11 in the figure) with the engaging recesses 66. Further, the rotating gear member 64 sequentially disengages the engaging elements 40 that were engaged with the engaging recesses 66, and the disengaged engaging elements 40 move away in the tangential direction (F12 in the figure).

[0071] As a result, the sheet curtain 32 moves downward while being guided by the pair of guide rails 14, closing the loading entrance 102. At this time, the sheet curtain 32 is unwound from the winding roll 20 against the biasing force acting on the winding roll 20 by a biasing member (not shown).

[0072] (Specific configuration of the engaging element 40) Next, the specific configuration of the engaging element 40 will be described. Regarding the shape of the engaging element 40, the direction in the state where the engaging element 40 is engaged with the engaging recess 66 of the gear member 64 is used.

[0073] Specifically, the arrow X shown in FIG. 7(B) indicates the radial direction of the gear member 64 (hereinafter referred to as the "gear radial direction"), and the arrow Y indicates the circumferential direction of the gear member 64 (hereinafter referred to as the "gear circumferential direction"). Further, the arrow X1 indicates the outer side in the radial direction of the gear member 64, that is, the side away from the rotation center of the gear member 64 (hereinafter referred to as the "outer side in the gear radial direction"), and the inner side in the radial direction of the gear member 64, that is, the side approaching the rotation center of the gear member 64 (hereinafter referred to as the "inner side in the gear radial direction").

[0074] As shown in FIG. 7(B), the engaging element 40 has a symmetrical shape with respect to the center line CL01 that passes through the center point of the through hole 46 and extends in the gear radial direction when viewed from the shutter width direction. And, a pair of side surfaces 40b facing the gear circumferential direction are formed on the engaging element 40. Among the plurality of engaging elements 40, the side surfaces 40b of adjacent engaging elements 40 contact each other. Then, the side surface 40b of the engaging element 40 moved by the gear member 64 pushes the side surface 40b of the adjacent engaging element 40, so that the plurality of engaging elements 40 move and the sheet curtain 32 moves. Thus, the side surface 40b is a contact surface that contacts the side surface 40b of the adjacent engaging element 40, and functions as a pressing surface that presses the side surface 40b of the adjacent engaging element 40.

[0075] Furthermore, in the engaging element 40, a contact portion 50 that contacts the contact block 80 (see FIG. 4) is formed in a portion on the outer side in the gear radial direction with respect to the pair of side surfaces 40b. Also, in the engaging element 40, an engaging portion 54 that engages with the engaging recess 66 (see FIG. 4) of the gear member 64 is formed in a portion on the inner side in the gear radial direction with respect to the pair of side surfaces 40b.

[0076] In the contact portion 50 of the engaging element 40, as shown in FIGS. 5 and 7(B) when viewed from the shutter width direction, a curved surface 50a formed at both end portions in the gear circumferential direction and a top surface 50b sandwiched between the pair of curved surfaces 50a and facing the outer side in the gear radial direction are formed. The top surface 50b is a surface orthogonal to the gear radial direction.

[0077] The curved surface 50a is an example of an inclined surface, and is a surface that is inclined in a curved shape from the side surface 40b to the top surface 50b. Specifically, the curved surface 50a is a curved surface that curves convexly toward the outer side in the gear diameter direction from each of the pair of side surfaces 40b to the top surface 50b.

[0078] In this configuration, when the engaging element 40 engaged with the engaging recess 66 moves outward in the gear diameter direction, the top surface 50b of the contact portion 50 of the engaging element 40 contacts the inner peripheral surface 80a of the contact block 80. As a result, the engagement state between the engaging portion 54 of the engaging element 40 and the engaging recess 66 of the gear member 64 is maintained.

[0079] As shown in FIGS. 5 and 7(B) when viewed in the shutter width direction, a pair of engaging planes 54a formed at both end portions in the gear circumferential direction and a contact surface 54b sandwiched between the pair of engaging planes 54a and facing the inner side in the gear diameter direction are formed on the engaging portion 54 of the engaging element 40.

[0080] The engaging plane 54a extends inward in the gear diameter direction from each of the pair of side surfaces 40b and is a surface that is in surface contact with the engaging recess 66. Further, the engaging plane 54a has a planar shape and is inclined when viewed in the shutter width direction. Specifically, the engaging plane 54a is inclined with respect to the center line CL01 so as to approach the center line CL01 as it goes from the outer side to the inner side in the gear diameter direction. Also, the contact surface 54b has a curved shape that is convex on the inner side in the gear diameter direction when viewed in the shutter width direction.

[0081] In the present embodiment, when the dimension along the gear diameter direction from the attachment center C1 (see FIG. 7(B)) of the engaging element 40 to the top surface 50b is LA (see FIG. 7(B)), and the dimension along the gear diameter direction from the attachment center C1 to the intersection point M1 of the side surface 40b and the curved surface 50a is LB (see FIG. 7(B)), LA / 2 ≥ LB. That is, when the dimension along the gear diameter direction from the intersection point M1 to the top surface 50b is LC (see FIG. 7(B)), LC ≥ LB.

[0082] As shown in FIG. 10, which is a view of the engaging member 40 from above, recesses 40g and chamfered portions 40f (specifically, C chamfers) are formed on the side portions of each of the plurality of engaging members 40. The chamfered portion 40f is disposed on the outer side (specifically, the right side) in the shutter width direction on the side portion. Further, the recess 40g is disposed on the intermediate portion in the shutter width direction on the side portion, that is, on the inner side (specifically, the left side) in the shutter width direction with respect to the chamfered portion 40f.

[0083] Each of the plurality of engaging members 40 is non-contact with the adjacent engaging member 40 at the recess 40g and the chamfered portion 40f. Each of the plurality of engaging members 40 contacts the adjacent engaging member 40 between the recess 40g and the chamfered portion 40f and on the inner side (specifically, the left side) in the shutter width direction with respect to the recess 40g. That is, the side surfaces 40b where the adjacent engaging members 40 contact each other are formed between the recess 40g and the chamfered portion 40f and on the inner side (specifically, the left side) in the shutter width direction with respect to the recess 40g.

[0084] Note that FIG. 10 shows the engaging member 40 disposed at the right end side portion of the sheet curtain 32, but the engaging member 40 disposed at the left end side portion of the sheet curtain 32 is configured in the same manner.

[0085] (Specific configuration of the engaging recess 66 of the gear member 64) In the engaging recess 66 of the gear member 64, as shown in FIG. 5 when viewed from the shutter width direction, a pair of side planes 66a formed at both end side portions in the gear circumferential direction and a bottom surface 66b sandwiched between the pair of side planes 66a and facing the outer side in the gear radial direction are formed. The side plane 66a has a planar shape, and the bottom surface 66b has a curved shape with the inner side in the gear radial direction being convex.

[0086] Also, in a state where the engaging portion 54 of the engaging member 40 is engaged with the engaging recess 66 to move the curtain unit 30 up and down, the bottom surface 66b of the gear member 64 is formed to be in surface contact (hereinafter referred to as "surface contact") with the contact surface 54b of the engaging member 40.

[0087] Furthermore, in a state where the engaging portion 54 of the engaging member 40 is engaged with the engaging recess 66 to move the curtain unit 30 up and down, one side plane 66a and one engaging plane 54a are in surface contact, and the other side plane 66a and the other engaging plane 54a are spaced apart. In other words, a gap is formed between the other side plane 66a and the other engaging plane 54a.

[0088] Also, as shown in FIGS. 4 and 5, an angle formed by a reference line S01 passing through the outermost point P01 in the gear radial direction and the axis center point P02 of the gear member on the side plane 66a and a straight line L01 extending along the side plane 66a is defined as an angle R01. On the other hand, when the engaging recess is an arc surface 100 that contacts the bottom surface 66b and passes through a pair of outermost points P01, an angle formed by a tangent line L11 at the outermost point P01 of this arc surface 100 and the reference line S01 is defined as an angle R02. Then, the side plane 66a of the engaging recess 66 and the engaging plane 54a of the engaging member 40 are formed such that the angle R01 is smaller than the angle R02. In this embodiment, as an example, the angle R01 is 19.5 [degrees] and the angle R02 is 30.6 [degrees].

[0089] Here, the outermost point P01 is an intersection point where the side plane 66a and the outer peripheral surface of the gear member 64 intersect when viewed from the shutter width direction. Therefore, when the corner formed by the side plane 66a and the outer peripheral surface of the gear member 64 is rounded (R is formed), the outermost point P01 is a virtual point.

[0090] (Operation of this embodiment) Next, the operation of this embodiment will be described.

[0091] In this embodiment, when the dimension of the engaging member 40 along the gear radial direction from the mounting center C1 (see FIG. 7(B)) to the top surface 50b of the sheet curtain 32 is LA (see FIG. 7(B)), and the dimension along the gear radial direction from the mounting center C1 to the intersection point M1 of the side surface 40b and the curved surface 50a is LB (see FIG. 7(B)), LA / 2 ≥ LB.

[0092] Therefore, compared with the case where LA / 2 < LB, the edge 50e (see FIG. 7(B)) formed by the side surface 40b and the curved surface 50a is located closer to the mounting center C1 side than the top surface 50b.

[0093] As a result, even when the sheet curtain 32 bends in a direction opposite to the direction in which it bends when moving along the circumferential direction of the gear member 64, compared with the case where LA / 2 < LB, the edges 50e of the adjacent engaging elements 40 are less likely to catch on each other, and interference between the engaging elements 40 is suppressed. As a result, damage to the engaging element 40 and the sheet curtain 32 can be suppressed. Note that the sheet curtain 32 bending in the reverse direction means a case where the sheet curtain 32 in a state of closing the loading entrance 102 (see FIG. 1) bends so that the front side becomes convex.

[0094] It is also desirable to configure the edge 50h to be small (for example, the angle to be gentle) also at the intersection M2 of the side surface 40b and the engaging plane 54a.

[0095] (Operation of this Embodiment by Comparison with Comparative Form) In the comparative form, instead of the engaging element 40 and the gear member 64, the engaging element 240 and the gear member 264 shown in FIGS. 11 to 13 are used.

[0096] The engaging element 240 has an engaging portion 254 that is different in shape from the engaging portion 54 of the engaging element 40. The engaging portion 254 of the engaging element 240 is formed with a pair of inclined surfaces 254a formed at both end portions in the gear circumferential direction and an engaging surface 254b when viewed from the shutter width direction.

[0097] The inclined surface 254a is inclined with respect to the center line CL01 when viewed from the shutter width direction. Specifically, the inclined surface 254a is inclined with respect to the center line CL01 so as to approach the center line CL01 as it goes from the outer side to the inner side in the gear radial direction. The engaging surface 254b is an arcuate surface that is convex on the inner side in the gear radial direction.

[0098] The gear member 264 has an engaging recess 266 that is different in shape from the engaging recess 66 of the gear member 64. As shown in FIG. 12, an arcuate surface 266a is formed in the engaging recess 266 when viewed in the shutter width direction. This arcuate surface 266a is the same surface as the aforementioned arcuate surface 100, and when viewed in the shutter width direction, it is a surface that contacts the bottom surface 66b of the engaging recess 66 according to the embodiment and passes through a pair of outermost points P01.

[0099] Also, as shown in FIG. 12, in a state where the engaging portion 254 of the engaging element 240 is engaged with the engaging recess 266 of the gear member 264, the arcuate surface 266a of the gear member 264 is in surface contact with the engaging surface 254b of the engaging portion 254. In other words, the engaging recess 266 of the gear member 264 and the engaging portion 254 of the engaging element 240 are in contact with each other on an arcuate surface.

[0100] Also, the angle R02 formed by the tangent line L11 at the outermost point P01 of the arcuate surface 266a and the reference line S01 is, as described above, 30.6 [degrees] as an example.

[0101] Here, consider the force transmitted from the rotating gear members 64 and 264 to the engaging elements 40 and 240 that are engaged with the engaging recesses 66 and 266 of the gear members 64 and 264.

[0102] In the comparative form, as shown in FIG. 12, when viewed in the shutter width direction, the arcuate surface 266a of the engaging recess 266 is in an arcuate shape. Also, the angle R02 formed by the reference line S01 (see FIG. 11) connecting the outermost point P01 and the axis center point P02 of the gear member 264 and the tangent line L11 is 30.6 [degrees] as an example in this embodiment.

[0103] Then, for example, the force (F13 in the figure) transmitted from the gear member 264 rotating in the negative direction (direction K02 in the figure) to the engaging element 240 acts in the tangential direction of the gear member 264 at the outermost point P01 at the outermost point P01.

[0104] On the other hand, the force (F14 in the figure) pushing the engaging element 240 acts in a direction orthogonal to the tangent line L11 at the outermost point P01. Therefore, if the force F13 transmitted from the gear member 264 to the engaging element 240 is set to "100", the force F14 pushing the engaging element 240 becomes "86".

[0105] Further, when the force F14 pushing the engaging element 240 is decomposed into a force acting in the gear circumferential direction and a force acting in the gear radial direction, the force acting in the gear circumferential direction becomes "74", and the force acting in the gear radial direction becomes "44".

[0106] On the other hand, in the sheet shutter 10 according to the present embodiment, as shown in FIG. 5, when viewed from the shutter width direction, the side plane 66a of the engaging recess 66 has a planar shape. Further, the angle R01 formed by the reference line S01 (see FIG. 4) connecting the outermost point P01 and the axial center point P02 of the gear member 64 and the straight line L01 extending along the side plane 66a is smaller than the angle R02, and in the present embodiment, as an example, it is set to 19.5 [degrees].

[0107] Then, for example, the force (F03 in the figure) transmitted from the gear member 64 rotating in the negative direction (direction K02 in the figure) to the engaging element 40 acts in the tangential direction of the gear member 64 at the outermost point P01.

[0108] On the other hand, the force (F04 in the figure) pushing the engaging element 40 acts in a direction orthogonal to the straight line L01 at the outermost point P01. Therefore, if the force F03 transmitted from the gear member 64 to the engaging element 40 is set to "100", the force F04 pushing the engaging element 40 becomes "94".

[0109] Further, when the force F04 pushing the engaging element 40 is decomposed into a force acting in the gear circumferential direction and a force acting in the gear radial direction, the force acting in the gear circumferential direction becomes "88", and the force acting in the gear radial direction becomes "31".

[0110] Thus, in the sheet shutter 10, the force that attempts to move the engaging member 40 in the gear circumferential direction becomes stronger compared to the comparative form. Also, in the sheet shutter 10, the force that attempts to move the engaging member 40 in the gear radial direction becomes weaker compared to the comparative form.

[0111] In addition, in the above-described operation, the force transmitted from the gear members 64 and 264 rotating in the negative direction to the engaging members 40 and 240 has been described. However, the force transmitted from the gear members 64 and 264 rotating in the positive direction to the engaging members 40 and 240 is the same as the case where the gear members 64 and 264 rotate in the negative direction.

[0112] As described above, in the sheet shutter 10, in the engaging recess 66 of the gear member 64, a pair of opposing side planes 66a in the gear circumferential direction and a bottom plane 66b sandwiched between the pair of side planes 66a are formed. Further, in the engaging member 40, an engaging plane 54a that is in surface contact with the pair of side planes 66a and a contact surface 54b that contacts the bottom plane 66b are formed. For this reason, compared to the comparative form in which the engaging recess 266 of the gear member 264 and the engaging member 240 are in contact with an arc surface, the movement of the engaging member in the circumferential direction of the arc surface is suppressed, so that the posture of the engaging member 40 with respect to the gear member 64 can be stabilized.

[0113] Also, in the sheet shutter 10, as described above, the force that attempts to move the engaging member 40 in the gear circumferential direction can be strengthened compared to the comparative form. In other words, compared to the comparative form in which the engaging recess is an arc surface, the force that attempts to move the engaging member 40 in the gear circumferential direction can be efficiently transmitted from the gear member 64 to the engaging member 40.

[0114] Also, in the sheet shutter 10, as described above, the force that attempts to move the engaging member 40 in the gear radial direction can be weakened compared to the comparative form. In other words, compared to the case where the engaging recess 266 is an arc surface, the frictional force generated between the engaging member 40 and the contact block 80 can be weakened.

[0115] In the sheet shutter 10, in a state where the engaging element 40 is engaged with the engaging recess 66 to move the curtain unit 30 up and down, one side plane 66a and one engaging plane 54a are in surface contact, and the other side plane 66a and the other engaging plane 54a are separated. Therefore, when the engaging element 40 approaching from the tangential direction of the gear member 64 is engaged with the engaging recess 66 by the rotation of the gear member 64, it is possible to suppress interference between the contact surface 54b of the engaging element 40 and the outer peripheral surface of the gear member 64.

[0116] In the sheet shutter 10, in a state where the engaging element 40 is engaged with the engaging recess 66 to move the curtain unit 30 up and down, the contact surface 54b formed on the engaging element 40 is in surface contact with the bottom surface 66b of the engaging recess 66. Therefore, compared with the case where the contact surface formed on the engaging element is in point contact with the bottom surface of the engaging recess, the posture of the engaging element 40 with respect to the gear member 64 can be stabilized.

[0117] (Modification of the shape of the engaging element 40) As the engaging element 40, an engaging element 140 having the shape shown in FIG. 14 may be used. As shown in FIG. 14, the engaging element 140 has a symmetrical shape with respect to the center line CL01 that passes through the center point (attachment center) C1 of the through hole 46 and extends in the gear diameter direction when viewed from the shutter width direction. Further, the engaging element 140 has a symmetrical shape with respect to the orthogonal line CL02 orthogonal to the gear diameter direction (center line CL01). Thus, the engaging element 140 is formed to be line-symmetrical with the center line CL01 as the axis of symmetry and line-symmetrical with the orthogonal line CL02 as the axis of symmetry.

[0118] In the engaging element 40, a pair of side surfaces 40b facing the gear circumferential direction are formed on the outer side and the inner side in the shutter width direction with respect to the orthogonal line CL02. The side surface 40b of the engaging element 140 has a dimension along the gear diameter direction that is smaller than the side surface 40b of the engaging element 40.

[0119] In the contact portion 50 of the engaging element 140, an inclined surface 150a is formed instead of the curved surface 50a. The engaging element 40 is a surface that is inclined in a planar shape from the side surface 40b to the top surface 50b.

[0120] Similar to the engaging portion 54 of the engaging element 40, the engaging portion 54 of the engaging element 140 is formed with a pair of engaging planes 54a formed at both end portions in the gear circumferential direction as viewed from the shutter width direction, and a contact surface 54b sandwiched between the pair of engaging planes 54a and facing the inner side in the gear diameter direction.

[0121] Also in the engaging element 140, similar to the engaging element 40, when the dimension along the gear diameter direction from the mounting center C1 (see FIG. 14) to the top surface 50b with respect to the sheet curtain 32 is LA (see FIG. 14), and the dimension along the gear diameter direction from the mounting center C1 to the intersection M1 of the side surface 40b and the curved surface 50a is LB (see FIG. 14), LA / 2 ≧ LB.

[0122] In the engaging element 140, since it is formed symmetrically with respect to the center line CL01 as the target axis and also symmetrically with respect to the orthogonal line CL02 as the target axis, for example, it can be used by being inverted with respect to the center line CL01 (specifically, inverted vertically in FIG. 14). Therefore, it is possible to attach the engaging element 140 to the sheet curtain 32 without checking the orientation (vertical position in FIG. 14) of the engaging element 140, and the manufacturing process and manufacturing equipment can be simplified.

[0123] (Other modifications) The angles of the angle R01 and the angle R02 described in the above embodiment are examples, and other angles may be used. It is only necessary that the angle R01 is smaller than the angle R02.

[0124] Also, in the above embodiment, although not particularly described, the pair of gear members 64 may be integrally formed as one gear member extending in the shutter width direction.

[0125] Also, in the above-described embodiment, although not particularly described, for the switching between the operation and non-operation of the motor that generates the driving force transmitted to the driving roll 60, a remote control or the like may be used.

[0126] Also, in this embodiment, although no concave portions or the like were formed on the contact surface 54b formed on the engaging member 40, concave portions or the like may be formed on the contact surface.

[0127] Also, in this embodiment, although no concave portions or the like were formed on the engaging plane 54a formed on the engaging member 40, concave portions or the like may be formed on the engaging plane.

[0128] Also, in this embodiment, although no concave portions or the like were formed on the bottom surface 66b formed in the engaging recess 66 of the gear member 64, concave portions or the like may be formed on the bottom surface.

[0129] Also, in this embodiment, although no concave portions or the like were formed on the side plane 66a formed in the engaging recess 66 of the gear member 64, concave portions or the like may be formed on the side plane.

[0130] The present invention is not limited to the above-described embodiment, and various deformations, changes, and improvements are possible without departing from the gist thereof. For example, a plurality of the above-described modification examples may be appropriately combined and configured.

Explanation of Reference Numerals

[0131] 10 Sheet shutter 20 Take-up roll 32 Sheet curtain 40 Engaging member 40a Side surface 50a Curved surface (an example of an inclined surface) 50b Top surface 54a Engaging plane 54b Contact surface 64 Gear member 66 Engaging recess 66a Side plane 66b Bottom surface 80 Contact block 100 Arc surface 150a Inclined surface 266a Arc surface C1 Mounting center CL01 Center line CL02 Orthogonal line L01 Straight line L11 Tangent line M1 Intersection point P01 Outermost point P02 Axis center point R01 Angle R02 Angle S01 Reference line

Claims

1. A sheet curtain wound around a winding roll, a plurality of engaging members attached along the winding direction of the winding roll to both side end portions of the sheet curtain, a gear member that rotates forward and backward in an engaged state with the engaging member and moves the sheet curtain along the circumferential direction of the gear, thereby winding or unwinding the sheet curtain around the winding roll to move the sheet curtain up and down, comprising: each of the plurality of engaging members, in the engaged state, faces the circumferential direction of the gear and has a pair of side surfaces that contact each other, in the engaged state, has a top surface facing radially outward of the gear member, and has an inclined surface that inclines in a planar or curved shape from each of the pair of side surfaces to the top surface, and has: when the dimension along the radial direction from the attachment center of the engaging member to the top surface with respect to the sheet curtain is LA, and the dimension along the radial direction from the attachment center to the intersection of the side surface and the inclined surface is LB, LA / 2 ≥ LB a sheet shutter.

2. each of the plurality of engaging members, when viewed along the axial direction of the gear member, is formed symmetrically with respect to a center line along the radial direction passing through the attachment center as an axis of symmetry, and is formed symmetrically with respect to an orthogonal line passing through the attachment center and orthogonal to the center line as an axis of symmetry The sheet shutter according to claim 1.

3. The gear member, has a plurality of engaging recesses formed side by side in the circumferential direction of the gear, and the engaging recesses engage with the engaging members to be in the engaged state, the engaging recess has a pair of side planes facing each other in the circumferential direction of the gear and a bottom surface sandwiched between the pair of side planes, and the engaging member has a pair of engaging planes in surface contact with the side planes and a contact surface in contact with the bottom surface The sheet shutter according to claim 1.

4. when viewed from the axial direction of the gear member, the angle formed by a reference line passing through the outermost point in the radial direction of the gear member and the axial center point of the gear member and a straight line extending along the side plane is smaller than the angle formed by the reference line and the tangent at the outermost point of the arc surface when the engaging recess is an arc surface that contacts the bottom surface and passes through the outermost point, The sheet shutter according to claim 3.

5. When viewed from the axial direction of the gear member, with the engaging element sandwiched therebetween, the engaging element that is disposed on the opposite side of the gear member and engaged with the engaging recess moves radially outward of the gear member, and includes a contact block with which the moved engaging element comes into contact. The seat shutter according to claim 4.

6. In a state where the engaging element is engaged with the engaging recess and the seat curtain is moved up and down, one of the side planes is in surface contact with one of the engaging planes, and the other side plane is spaced apart from the other engaging plane. The seat shutter according to claim 3.

7. In a state where the engaging element is engaged with the engaging recess and the seat curtain is moved up and down, the contact surface formed on the engaging element is in surface contact with the bottom surface formed in the engaging recess. The seat shutter according to claim 3.

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