JP5030295B2 - Door opener - Google Patents

Description

  The present invention relates to an upper feed for storing a door constituted by door slats that are guided by guide rails provided on the left and right sides of the opening to open and close vertically, and that is fed into a guide groove extending horizontally from the upper end of the guide rail. The present invention relates to a built-in door opening and closing device.

  In homes where there are elderly people and wheelchair users, various doors for closing living rooms, bathrooms, toilets, closets and the like are automatically or manually opened and closed. In this case, if the door is a sliding door such as a shutter, a wide opening and a wall surface for drawing the sliding door are required. For this reason, there may be a case of double door opening, but a large space is required to ensure the movement of the door.

  Therefore, in Patent Document 1 below, the door (shutter) is constituted by a continuous combination of door slats (panels) that are guided by guide rails provided on both sides of the opening to open and close, and the door slats are formed from the upper ends of the guide rails. Proposals have been made to send an oval spiral guide groove (storage rail) provided in the horizontal direction and store it above the opening (upper feed shutter). The ceiling space can be used effectively as a space. However, the drive parts such as the rotating shaft and gearbox provided on the uppermost door slat are configured to move together as the door slat opens and closes. A large force is required for opening and closing operations regardless of electric operation.

For this reason, a balance spring that constantly biases the door slat toward the open (upward) side is interposed in the shaft of the drive unit, but the spring itself also moves, thereby increasing the weight of the door slat. become. In addition, since the drive motor is moved when it is electrically driven, it is necessary to provide a wiring space in the guide rail for supplying electric power in addition to adding the weight of the motor to the moving part. However, there is a problem that the space has to be enlarged so that the wiring can move as the door slat is opened and closed. Furthermore, in the example of Patent Document 1, since the guide groove is formed in a spiral shape, the formation of the guide groove is complicated, and the curvature radius of the curved portion at the end of the spiral portion is gradually reduced. When the width in the height direction cannot be reduced, the door slat passing through the curved portion in a bent state cannot be moved smoothly, and a very large driving force is required.
JP-A-6-330678

  The present invention employs an upper feed-type door in which a single oval guide groove is provided above the opening, and a door slat is fed into the guide groove, thereby improving the efficiency of the drive mechanism and the balance mechanism. Is.

  Under the above-mentioned problems, the present invention provides a door slat according to claim 1 in which doors comprising a plurality of door slats connected vertically so as to be opened and closed by opening and closing the opening are provided on both left and right sides of the opening. The guide rail is guided from the upper end of the guide rail and is stored in a guide groove extending in a long oval shape in the horizontal direction, and the unwinding force according to the delivery amount of the door slat sent to the opening by the tightening amount. In an upper feeding type door opening and closing device in which a coil spring to be exhibited is provided and winding or unwinding of the coil spring is interlocked with the movement of the door slat, the guide groove includes at least a first bending portion connected to the guide rail, and a guide A second bending portion on the side away from the rail, an upper straight portion connecting the two bending portions at the upper portion, and a lower straight portion extending from the lower portion of the second bending portion toward the guide rail. The first and second feed wheels are provided on the axes passing through the respective bending centers of the first and second curved portions, and the endless circulator is wound around the first and second feed wheels, and the door slat is provided on the endless circulator. On the other hand, a door opening and closing device is provided, in which a coil spring is wound and unwound by rotation of a first or / and second feed wheel.

  According to the present invention, the radius of the first and second feed wheels described in claim 2 is smaller than the bending radius of the first and second curved portions of the guide groove, and the door slat is fully filled. Means for rotating the connection point between the endless circulation body and the door slat as far as one turn in the guide groove when fully fed out from the fed state, and in these, the first or When a coil spring drive system for winding and unwinding a coil spring is provided between one feed wheel of the second feed wheel and the coil spring, and the feed wheel rotates from the fully fed door slat to the door slat delivery side. Provided is a means for incorporating a delay mechanism in the coil spring drive system, in which the coil spring starts tightening with a delay of a predetermined rotation angle.

  Further, in this case, the coil spring according to claim 4 has one end as a fixed end and the other end fixed to a spring shaft that is rotatably provided by extrapolating the coil spring, and the spring shaft is a spring shaft wheel as a rotation end. The coil spring drive system is configured by supporting one feed wheel with the mounting shaft, fixing the winding wheel to the mounting shaft, and winding the endless circulation body around the winding wheel and the spring shaft wheel, A pin is provided on the winding wheel so that the pin is inserted into a groove having a discontinuous portion on the circumference formed on the side of one feed wheel, and one feed wheel is loosely fitted to the mounting shaft to delay the mechanism. The discontinuous portion described in claim 5 is a weir that closes the groove, and the weir is provided so as to be fixed at an arbitrary position on the circumference. Bending radius and door slat up and down The relationship Sato, is obtained by providing a means of bending angle of the door slats between the upper and lower is set to be greater than 90 degrees over the entire circumference curved portion when passing through the curved portion.

  According to the configuration of the first aspect, the portion that moves with the movement of the door slat is only the member that constitutes the door slat. Therefore, the force required for driving may be small. In this regard, the manual operation is light, and the automatic operation can reduce the capacity of the motor or the like that is the driving source. In the case of an upper-feeding type door, the weight associated with the amount of door slats sent (hanging into the guide rail) is positive for the driving force in the sending direction and the driving force in the feeding direction. It works negatively. For this reason, a coil spring (balance spring) corresponding to the delivery amount of the door slat with a rewinding force based on the winding amount is provided, and in claim 1, the feed rotates at a rotation angle corresponding to the delivery amount of the door slat. The coil spring is wound or unwound by the wheel.

  Therefore, since these coil springs and their drive systems can be fixedly provided, the moving weight of the door slat does not increase. Further, at the portion where the door slats reach the curved portion of the guide groove, the door slats are bent up and down, and the door slats are rotated so as to be lifted to increase the resistance. Although this resistance is reduced by reducing the vertical length of the door slat, the amount of members used increases, and there are cases where it cannot be made extremely small due to design restrictions. Therefore, according to the configuration of the second aspect, the bending radius of the curved portion of the guide groove is not reduced more than necessary, and accordingly, the movement resistance is suppressed to a small value even if the vertical length of the door slat is increased.

  In the above case, when the feed wheel and the coil spring are directly connected, the door slat starts to feed out and the coil spring is wound at the same time, and the delivery amount of the door slat sufficiently adds to the driving force in the delivery direction. During this time, a winding torque of the coil spring is required, and a large driving force is required in combination with a large driving torque required at the time of starting. Therefore, if the delay mechanism of claim 3 is adopted, when the coil spring starts to be wound, the door slat has already been sent out to some extent and this reduces the driving force, so that it can be moved with a light force regardless of whether it is manual or automatic. . In particular, when the electric motor is used automatically, the capacity can be reduced, which contributes to cost reduction and space saving. According to the means of claim 4, the delay mechanism is simplified, and according to the means of claim 5, the winding tightening start can be adjusted to an arbitrary angle in one rotation of the feed wheel (360 °), Adjustment according to settings such as the size and weight of the door slat, the strength of the coil spring, and the radius of curvature of the curved portion of the guide groove becomes easy. Furthermore, according to the means of claim 6, the bending angle between the upper and lower door slats moving in the bent state at the first curved portion and the second curved portion of the guide groove does not become too small, and this is moved. Can be used without requiring large torque.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 are cross-sectional views corresponding to AA in FIG. 5 showing the delivery and delivery of door slats, FIG. 4 is a cross-sectional view along BB in FIG. 2, and FIG. 5 is a cross-sectional view along CC in FIG. 6 is a front view showing a connection state of door slats, FIG. 7 is a side view of the same, and FIG. 8 is an enlarged view of a main part of FIG. 1, but the door according to the present invention is a plurality of doors made of horizontally long rectangular panels. The slat 1 is composed of a guide roller 2 provided on a side surface of the slat 1 so as to be able to be bent with a rotation shaft as a hinge. The vertical length (short width) of the door slat 1 is set to about 300 to 500 mm. In the following description, the direction in which the guide groove 11 moves away from the guide rail 28 is the back (rear), and the direction in which the guide groove 11 approaches the guide rail 28 is the front (front).

  The guide roller 2 is attached by attaching brackets 3 and 4 that overlap and overlap each other on both upper and lower side surfaces of the door slats 1 adjacent to each other in the vertical direction. The pin 5 is passed through the position of the first joint, and the guide roller 2 is rotatably attached to the protruding portion of the pin 5. In this case, when the upper and lower door slats 1 are joined in a vertical state, the upper and lower end surfaces of the brackets 3 and 4 are in contact with each other to regulate the position. , A convex portion 6 and a concave portion 7 are formed on each of them to fit each other. This is to prevent a gap from being formed between the door slats 1 and to restrict the bending so as to maintain the rigidity of the door. The mounting position of the guide roller 2 is offset to the back side (right side in FIG. 1) with respect to the thickness direction of the door slat 1, and according to this, the upper and lower door slats 1 can be bent in a direction sandwiching the guide roller 2 become.

  In the door slat 1 described above, the left and right end portions (guide rollers 2) are inserted into the guide rails 28 on both the left and right sides of the opening, and the uppermost door slat 1 is provided in front of and behind the opening. The first feed wheel 8 and the second feed wheel 9 having the same diameter are wound around the outer circumference of the first feed wheel 8 and the second feed wheel 9 and connected to an endless circulator 29 that is elongated in the longitudinal direction. For the connection, a connecting tool 36 provided with a guide roller 2 is used and is connected to the uppermost door slat 1 in this example, but can be connected to another door slat 1. The endless circulator 29 uses a toothed belt or chain that does not cause any slippage, and the feed wheel 8 and the feed wheel 9 are provided with tooth shapes and meshed with each other.

  Therefore, when one of the feed wheels 8, 9 is driven, the endless circulation body 29 rotates, and at the same time, the uppermost door slat 1 is accompanied by the guide groove along the circulation track of the endless circulation body 29 with the other door slats 1. The first feed wheel 8 is placed on the front surface side of the opening, and the door slat 1 to be fed is lowered while being guided by the guide rail 28 to close the opening. The first feed wheel 8 and the second feed wheel 9 are accommodated in a box 10 (may be a frame) provided in the upper part of the opening, and usually the box 10 is installed in the ceiling space. . And the guide groove 11 which the guide roller 2 of the door slat 1 rushes and rolls in the inner surface of the right and left of the box 10 is formed.

  The guide groove 11 extends so as to have an oval shape as a whole at a position offset from the circulation track of the endless circulator 29 to the outer peripheral side by a predetermined interval. Specifically, from the upper end of the guide rail 28 located at the front, the quadrant-shaped first curved portion 37 is followed by the upper horizontal straight line portion 38, and the semicircular second curved portion 39 is formed from the rear end thereof. After that, the third curved portion 41 having a circular arc shape less than a quadrant extends from the front end of the lower straight portion 40 and extends upward. As shown in FIG. 1, the third bending portion 41 in this case is a portion that accommodates the uppermost door slat 1 in a state where all the door slats 1 have been fed, and the total extension and accommodation of the guide groove 11. Depending on the length relationship of the door slat 1 to be used, it may be omitted. The turning radii of the curved portions 37, 39, 41 of this example are all set to be the same, and the first and second mounting shafts 12 that support the first and second feed wheels 8, 9 on the axis of the curved center, respectively. , 17 are provided. In this way, the guide roller 2 can smoothly travel in the guide groove 11 as the endless circulator 29 rotates.

  The first feed wheel 8 is fixedly fitted to both ends of the first mounting shaft 12 extending to the left and right of the box 10, and the drive wheel 13 is fixedly fitted to one end side (left side in FIG. 5) of the first mounting shaft 12. It is driven by an endless circulator 16 from an output wheel 15 attached to an output shaft of a drive motor 14 provided nearby. The second feed wheel 9 is loosely fitted with bearings 18 to both ends of the second mounting shaft 17 extending to the left and right of the box 10, and a winding wheel 19 is firmly fitted to both ends of the second mounting shaft 17. Yes. Further, a coil spring 20 for balancing the weight of the door slat 1 is provided in the vicinity of the second feed wheel 9 so as to be externally attached to the spring shaft 21, and a spring is provided on one end side (the left side in FIG. 5) of the spring shaft 21. The shaft wheel 22 is fixedly fitted. In this case, one end of the coil spring 20 is fixed (fixed end), and the other end is fixed to the spring shaft 21 so as to be rotatable (rotating end). The winding wheel 19 and the spring shaft wheel 22 of the second mounting shaft 17 are connected by an endless circulator 23. These endless circulators 16 and 23 use toothed belts or chains that do not cause slippage as in the case of the endless circulator 29 described above, and the winding wheel 19 and the spring shaft wheel 22 are provided with tooth shapes and meshed with each other. To.

  As described above, when the second attachment shaft 17 is rotated by the rotation of the endless circulator 29, the spring shaft 21 is rotated and the coil spring 20 is wound or unwound. This winding torque is proportional to the winding amount of the coil spring 20 and may be small at the beginning when the winding amount is small (the start of feeding of the door slat 1 or the end of feeding), but at the end when the winding amount is large (the end of feeding of the door slat 1) It will be big at the beginning of sending). However, on the other hand, the weight due to the delivery amount of the door slat 1 acts positively in the direction in which the door slat 1 is delivered, and eventually the delivery amount and the winding torque are not perfect, but are balanced. However, in the case of the upper feeding type door, the guide roller 2 passes through the second curved portion 39 from the lower straight portion 40 of the guide groove 11 and rotates to the upper straight portion 38 while moving up and down. Since the force acting in the direction in which the door slat 1 bends and feeds out the door slat 1 becomes smaller, and the guide roller 2 is pressed against the guide groove 11, the door slat 1 is tightened while the coil spring 20 is tightened during this time. In order to move, generation of a large driving torque is required.

Therefore, the present invention is provided with a delay mechanism 24 that delays the drive of the spring shaft 21 when the door slat 1 starts to be fed, and the feed amount of the door slat 1 (from the first curved portion 37 of the guide groove 11 to the guide rail 28). At first, when the large number of door slats 1 hanging down is required and a large driving torque is required, the coil spring 20 is wound by rotating only the second feed wheel 9 without rotating the spring shaft 21. The door slat 1 is sent out without tightening. The delay mechanism 24 of the present example has a pin 25 protruding from the side surface of the winding wheel 19 fitted to the second mounting shaft 17, and the pin 25 is formed in a circular shape formed on the side surface of the second feed wheel 9. A dam 27 is provided at a predetermined position (one place in this example) of the groove 26 so as to enter the groove 26. The pin 25 is positioned in front of the weir 27 (second feed wheel 9) in the rotational direction. In this example, since the coil spring 20 is divided into two at the center, a pair of delay mechanisms 24 each including a pin 25 and a weir 7 are provided in the left and right second feed wheels in phase.

  According to this, at first, only the second feed wheel 9 is rotated in conjunction with the rotation of the endless circulator 29, so that the driving torque may be small. When the rotation is almost complete, the weir 27 pushes the pin 25 (see FIG. 2). State), after that, the winding wheel 19, that is, the spring shaft 21 is rotated to start winding the coil spring 20. At this time, the door slat 1 is fed out to some extent, and its weight is added to the feeding direction. It does not require a large driving torque. The coil spring 20 can be directly wound or loosened by the rotation of the second feed wheel 9, and in that case, the coil spring 20 is on the side opposite to the drive wheel 19 of the second mounting shaft 17 (right side in FIG. 5). A winding wheel 19 may be attached to the second feed wheel 9 at the end, and the spring shaft wheel 22 and the endless circulator 23 may be provided at a position where the left and right are reversed. Further, the delay mechanism 24 may not be provided. In this case, the coil spring 20 may be directly wound or loosened by the rotation of the first or second feed wheel 8 or 9.

  When the bending angle α (see FIG. 8) of the upper and lower door slats 1 is less than a certain limit (90 °), the component of the force acting in the direction of feeding the upper door slat 1 is reduced, and the guide roller 2 moves into the guide groove 11. A very large driving torque is required to cause strong rolling and rolling. Therefore, in this example, the drive torque is reduced by suppressing the minimum bending angle α to 110 °. The setting of the minimum bending angle α is determined by the relationship between the radius of rotation of the curved portion of the guide groove 11 and the vertical length of the door slat 1, but the larger the bending radius of the first and second curved portions 37, 39, As the vertical length of the door rat 1 is smaller, the minimum bending angle α can be increased. However, it is preferable that the bending radius is small in terms of space, and it is possible to reduce the number of members such as the guide roller 2 and the brackets 3 and 4 when the vertical length of the door slat 1 is set large. There is a need to.

  On the other hand, the operating range of the delay mechanism 24 is set to a range of almost one round from the position where the weir 27 contacts the pin 25 to the contact again with the pin 25 in this example. It is necessary to set in consideration of the balance of the vertical length and weight of the door rat 1 and the winding torque of the coil spring 20, and it is desirable that the operating range can be easily adjusted by changing the mounting position of the weir 27. It is preferable that the weir 27 is moved to an arbitrary position in the groove 26 and can be fixed again by means such as screw fixing. Further, by doing so, it becomes possible to set the optimum operating range in the case where a deviation occurs due to long-term use and the need for readjustment arises, or due to individual differences such as manufacturing errors. Even when the operating range of the delay mechanism 24 is set to be small, the weir 27 exists at a position away from the pin 25 in the fully open state of the door slat 1 (the state of FIG. 1).

  When the door slat 1 is fed out to the maximum and the opening is closed (in the state shown in FIG. 3), the coil spring 20 is also wound accordingly so that the unwinding force and the weight of the door slat 1 are balanced. In this respect, the drive motor 14 may have a small capacity all the time, and the cost can be reduced and the space can be reduced. On the other hand, when opening the opening, the drive motor 14 is driven to wind up the door slat 1. At this time, the pin 25 and the weir 27 are pressed against each other in a balanced state and stopped, and the weir 27 rotates in a direction away from the pin 25 by the forced rotation of the feed wheel 9, whereby the pin 25 is While pushing the weir 27 with the rewinding force of the coil spring 20, it rotates at the same speed and always generates a force that balances the weight of the door slat 1. Therefore, when the door slat 1 is completely wound, the coil spring 20 is returned to the initial state (before the delay mechanism 24 is activated).

  When the endless circulator 29 is loosened due to long-term use, the open / close operation may be hindered. In this example, an auto tension mechanism is provided so as not to cause this loosening. In this example, as shown in FIG. 5, both ends of a slide shaft 31 extending in the front-rear direction are fixed in the case 30 fixed to the left and right side surfaces of the box 10, and the thrust bearing 32 is attached to the slide shaft 31 as the auto tension mechanism. A movable case 33 is slidably mounted via a shaft, and a feed shaft 17 protruding from the left and right side surfaces of the box 10 is rotatably attached to the movable case 33 via an automatic alignment bearing 34. Then, the compression spring 35 is extrapolated to the portion of the slide shaft 31 between the thrust bearing 32 and the case 30 of the movable case 33, and the feed shaft 17 attached to the movable case 33 is always pressed to the back side by the repulsive force. Mechanism. According to this, since the second feed wheel 9 loosely fitted to the second mounting shaft 17 with the bearing 18 tends to always move rearward along the slide shaft 31, the endless circulator 29 is always kept in a tensioned state. Be drunk. Such an auto-tension mechanism can be omitted when a timing belt or the like with relatively little elongation is employed as the endless circulator 29.

  By the way, in this example, although the case where the 1st and 2nd feed wheels 8 and 9 were set to the same diameter was shown, naturally a thing with a different diameter can also be made (illustration omitted). In this case, the first and second curved portions 37 and 39 of the guide groove 11 have different diameters offset from the outer diameters of the first and second feed wheels 8 and 9 provided at the concentric positions by a certain width. That's fine. When the first and second feed wheels 8 and 9 having different front and rear diameters are used, of course, it is necessary to incline at least one of the upper and lower straight portions of the endless circulator 29, and the straight portions 38 of the upper and lower steps of the guide groove 11. , 40 are also provided at positions offset outward by a certain width from this, so that at least one of the upper and lower straight portions 38, 40 is similarly inclined. These settings may be determined in consideration of the balance relationship between the winding torque of the coil spring 20 and the weight of the door slat 1 and the minimum bending angle α between the door slats 1. Also, the front-rear relationship between the first feed wheel 8 and the second feed wheel 9, that is, the components of the drive system related to the drive motor 14 and the coil spring 20 can be interchanged before and after. Thus, it is preferable to arrange the drive motor 14 in the foreground because the distance of the wiring with the operation switches provided in the vicinity of the opening can be shortened.

  As described above, since the door opening and closing device of the present invention balances the weight of the door slat 1 by the action of the coil spring 20, it does not necessarily require forced drive by the drive motor 14, and can be operated with a light force even if it is manual. Is possible. In the case of manual operation, it goes without saying that the configuration of the drive motor 14, the output wheel 15 and the endless circulator 16 can be omitted, and the cost can be reduced. In addition, even when forced driving is performed, in the event of a power outage or when a trouble occurs where the drive motor 14 does not move, it can be easily opened and closed manually without any special operation. Since there is no risk that the door rat 1 will descend without permission, it can be used with confidence.

FIG. 6 is a cross-sectional view corresponding to AA in FIG. FIG. 6 is a cross-sectional view corresponding to AA in FIG. FIG. 6 is a cross-sectional view corresponding to AA in FIG. It is BB sectional drawing sectional drawing in FIG. It is CC sectional drawing in FIG. It is a front view which shows the connection state of a door rat. It is a side view which shows the connection state of a door rat. It is a principal part enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Doslat 2 Guide roller 3 Bracket 4 Bracket 5 Pin 6 Protrusion 7 Concave 8 First feed wheel 9 Second feed wheel 10 Box 11 Guide groove 12 First mounting shaft 13 Drive wheel 14 Drive motor 15 Output wheel 16 Endless circulation body 17 Second mounting shaft 18 Bearing 19 Winding wheel 20 Coil spring 21 Spring shaft 22 Spring shaft wheel 23 Endless circulation body 24 Delay mechanism 25 Pin 26 Groove 27 Weir 28 Guide rail 29 Endless circulation body 30 Case 31 Slide shaft 32 Thrust bearing 33 Movable Case 34 Self-aligning bearing 35 Compression spring 36 Connector 37 First bending portion 38 Upper straight portion 39 Second bending portion 40 Lower straight portion 41 Third bending portion

Claims (6)

A door consisting of a plurality of door slats that can be bent vertically to open and close the opening is extended from an upper end of a guide rail that guides door slats provided on both the left and right sides of the opening into a long oval shape in the horizontal direction. A coil spring is provided that exhibits a rewinding force according to the feed amount of the door slat that is fed into the opening by the amount of tightening and is stored in the guide groove. In the upper feed type door opening and closing device linked to the movement,
The guide groove includes at least a first bending portion connected to the guide rail, a second bending portion on the side away from the guide rail, an upper straight portion connecting the two bending portions at the upper portion, and a lower portion of the second bending portion. A lower straight portion extending toward the guide rail,
First and second feed wheels are provided on axes passing through the respective bending centers of the first and second curved portions, and endless circulation bodies are wound around the first and second feed wheels, and door slats are connected to the endless circulation bodies. On the other hand, the door opening and closing apparatus characterized by winding and rewinding the coil spring by rotation of the first or / and second feed wheel.   When the radius of the first and second feed wheels is smaller than the bending radius of the first and second curved portions of the guide groove, and when the door slat is fully fed from the fully fed state, The door opening and closing device according to claim 1, wherein the connection point with the door slat is rotated up to one round in the guide groove.   A coil spring drive system that winds and unwinds the coil spring between one feed wheel of the first or second feed wheel and the coil spring is provided, and the feed wheel feeds the door slat to the door slat delivery side. The door opening and closing device according to claim 1 or 2, wherein a delay mechanism for starting the tightening with a delay of a predetermined rotation angle when the coil spring rotates is incorporated in the coil spring drive system.   The coil spring has one end fixed and the other end is fixed to a spring shaft that can be rotated by extrapolating the coil spring, and the spring shaft is fixed to the spring shaft as a rotation end, and one feed wheel is attached to the mounting shaft. The coiling wheel drive system is constructed by winding the endless circulator around the coiling wheel and the spring shaft wheel, and the pin is projected from the coiling wheel. 4. The door opening and closing device according to claim 3, wherein a delay mechanism is formed by inserting into a groove having a discontinuous portion on a circumference formed on a side surface of one feed wheel and loosely fitting one feed wheel to an attachment shaft.   The door opening and closing device according to claim 4, wherein the discontinuous portion is a weir that closes the groove, and the weir is provided so as to be fixed at an arbitrary position on the circumference.   Claim that the relationship between the bending radius of the bending portion and the vertical length of the door slat is set so that the bending angle between the upper and lower door slats when passing through the bending portion is larger than 90 degrees over the entire bending portion. Item 6. The door opening and closing device according to any one of items 1 to 5.

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