JP2004258149A - Opening and closing mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an opening and closing mechanism for setting the open limit of an opening and closing member at a desired angle from a front side in simple operation. <P>SOLUTION: The opening and closing mechanism 4 is provided with a hinge 40, an engaging member 41, a locking pin 42, and an operation lever 43 being an open limit operation member. The hinge 40 is provided between the body 2 of an image forming apparatus 1 and a platen cover 3 serving as the opening and closing member. The operation lever 43 is provided on the side of the image forming apparatus 1 as the neighborhood of the hinge 40 is a support point. The engaging member 41 is a plate-like shape, attached to a shaft 43a at the support point of the operation lever 43, and engaged with the locking pin 42 provided on the side of the platen cover 3. When the angle of the operation cover 43 is changed, the angle of the engaging member 41 is changed, and the engaged position with the locking pin 42 is changed. Consequently, the open limit of the platen cover 3 can be set. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an opening / closing member provided substantially horizontally on the upper surface of a device, with a hinge provided on the back side of the device serving as a fulcrum, and a hand placed on the free end located on the front side of the device to substantially open the vertical surface. The present invention relates to an opening / closing mechanism that can be opened and closed with a switch.
[0002]
[Prior art]
For example, an image forming apparatus such as a copying machine or a scanner is provided with a document holder for holding a document placed on a document table. This document holder is provided on the upper surface of the image forming apparatus, and there is a document holder having an automatic document feeder in the document holder itself. An opening / closing mechanism for opening / closing the document in a substantially vertical plane with a hinge provided on the back side of the image forming apparatus as a fulcrum, with a hand on a free end located on the front side of the image forming apparatus. The opening / closing operation is made possible. The user performs an opening / closing operation by placing a hand on the front side of the document holder and pushing up and down the document holder.
[0003]
A toggle mechanism is incorporated in the hinge of the opening / closing mechanism. Thus, when the document presser is opened to a predetermined angle and then released, the document presser is opened by itself and reaches its limit and maintains that state. When the document holder is closed to an angle different from the above and the hand is released, the document holder is brought into close contact with the upper surface of the image forming apparatus by itself to be completely closed.
[0004]
Here, when the user is a short person or a person with a disability due to illness or injury and cannot reach a high place, the document holder is closed when the document holder is opened and reaches the limit. A problem arises that it is not possible.
[0005]
As a countermeasure, the opening limit of the document press is restricted by using a member such as a stopper, and as seen in Patent Document 1, the opening limit of the document press is adjusted by using a lock member in addition to this stopper. An opening / closing mechanism that can be operated has been proposed.
[0006]
[Patent Document 1]
JP 2001-296710 A
[Problems to be solved by the invention]
However, the opening limit of the document press that allows the user to hook the free end of the document press differs depending on the user. For this reason, restricting the opening limit to a predetermined angle by the stopper as in the above opening / closing mechanism causes a problem that operability is deteriorated. In addition, the operation of adjusting the opening limit of the document press requires the user to move to the rear side of the apparatus or to reach the rear side of the apparatus for operation, which is very time-consuming. This is even more inconvenient for people with disabilities such as illness or injury.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has an opening / closing member provided substantially horizontally on the upper surface of a device, and a hinge provided on the back side of the device serving as a fulcrum. Provided is an opening / closing mechanism that can be opened and closed in a substantially vertical plane by putting a hand on an end, wherein the opening limit of the opening / closing member can be set to a desired angle by a simpler operation than the front side of the device. With the goal.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an opening / closing member provided substantially horizontally on the upper surface of a device, with a hinge provided on the back side of the device as a fulcrum, at a free end located on the front side of the device. In an opening / closing mechanism which can be opened and closed in a substantially vertical plane by hand, an opening limit setting means for the opening / closing member is provided, and an operating means for operating the opening limit setting means is arranged on the front side of the device.
[0010]
According to this configuration, the opening limit of the opening / closing member can be set to a desired angle from the front side of the device. As a result, the user himself / herself can set the opening limit of the opening / closing member to a desired angle, thereby making it possible to solve the problem that the user cannot access the opening / closing member. In addition, since the user does not need to move to the back side of the device or reach his hand to set the opening limit of the opening / closing member, it is very convenient because it does not take much time.
[0011]
Further, an operation member is provided on a side surface of the device, with the vicinity of the hinge as a fulcrum, the front side of the device as a free end, and an opening limit of the opening / closing member set by changing its own angle.
[0012]
According to this configuration, it is possible to easily set a desired opening limit of the opening / closing member only by directly changing the angle of the operation member by hand. As a result, the opening limit setting means for the opening / closing member can be obtained with a simpler configuration. As a result, the structure can be simplified and an increase in manufacturing cost can be suppressed. In addition, since the operation can be easily performed from the front side of the device, no labor is required and this is convenient.
[0013]
Further, the tension point of the string-shaped member connected to the opening / closing member is the opening limit of the opening / closing member, and the extension amount adjusting member of the string-shaped member is arranged on the front side of the device.
[0014]
According to this configuration, it is possible to easily adjust the opening limit of the desired opening / closing member only by adjusting the amount of feeding of the cord-shaped member. As a result, the opening limit setting means for the opening / closing member can be obtained without forming a complicated configuration. In addition, since the operation can be performed from the front side of the device, it is convenient and time-consuming.
[0015]
Further, the cord-like member is fed out from the electric reel, and the operation means of the electric reel is arranged on the front side of the device.
[0016]
According to this configuration, it is possible to automatically and quickly adjust the amount by which the cord-shaped member is extended. As a result, for example, if a button in which a predetermined opening limit is set in advance is provided in the operation means, the opening limit of the opening / closing member can be set more easily by pressing one of the buttons, thereby shortening the working time. And operability can be improved. Further, since it is only necessary to connect the electric reel and the operation means with a signal cable, the opening / closing mechanism can be made more compact.
[0017]
In addition, the point at which the rack projecting from the device engages with the opening / closing member is the opening limit of the opening / closing member, and a pinion rotation operating member for changing the amount of projection of the rack is arranged on the front side of the device. .
[0018]
According to this configuration, it is possible to easily adjust the opening limit of the desired opening / closing member only by adjusting the protruding amount of the rack. As a result, the opening limit setting means for the opening / closing member can be obtained without forming a complicated configuration. In addition, since the operation can be performed from the front side of the device, it is convenient and time-consuming.
[0019]
Further, the pinion is rotated by a motor, and operation means for the motor is arranged on the front side of the device.
[0020]
According to this configuration, the protrusion amount of the rack can be automatically and quickly adjusted. As a result, for example, if a button in which a predetermined opening limit is set in advance is provided in the operation means, the opening limit of the opening / closing member can be set more easily by pressing one of the buttons, thereby shortening the working time. And operability can be improved. Further, since it is only necessary to connect the motor and its operating means with a signal cable, the opening and closing mechanism can be made more compact.
[0021]
Further, the time at which the crank rod protruding from the device is engaged with the opening / closing member is the opening limit of the opening / closing member, and the rotating operation member of the crank for changing the projecting amount of the crank rod is provided on the front side of the device. Placed.
[0022]
According to this configuration, it is possible to easily adjust a desired opening limit of the opening / closing member only by adjusting the protrusion amount of the crank rod. As a result, the opening limit setting means for the opening / closing member can be obtained without forming a complicated configuration. In addition, since the operation can be performed from the front side of the device, it is convenient and time-consuming.
[0023]
Further, the crank is rotated by a motor, and operation means for the motor is arranged on the front side of the device.
[0024]
According to this configuration, the protrusion amount of the crank rod can be automatically and quickly adjusted. As a result, for example, if a button in which a predetermined opening limit is set in advance is provided in the operation means, the opening limit of the opening / closing member can be set more easily by pressing one of the buttons, thereby shortening the working time. And operability can be improved. Further, since it is only necessary to connect the motor and its operating means with a signal cable, the opening and closing mechanism can be made more compact.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, it is assumed that the device provided with the opening / closing mechanism is designed as an image forming apparatus such as a copying machine or a scanner.
[0026]
FIG. 1 is a top perspective view of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 includes a main body 2 and a document holder 3, and an opening / closing mechanism 4 is provided therebetween.
[0027]
The main body 2 is provided with a document reading section 20, a copy operation section 21, and a copy paper discharge section 22. The document reading section 20 is provided on the upper surface of the main body 2, the copy operation section 21 is provided on the front side, and the copy paper discharge section 22 is provided in the lower body of these. A document is placed on the document reading unit 20, the document holding unit 3 is closed, and a predetermined operation is performed by the copy operation unit 21 so that the copied sheet is discharged to the copy sheet discharge unit 22.
[0028]
The document presser 3 serving as an opening / closing member is opened and closed in a substantially vertical plane by holding a free end located on the front side of the image forming apparatus 1 with a hinge 40 provided on the back side of the image forming apparatus 1 as a fulcrum. (Arrow A). The document presser 3 is opened to place or remove a document on the document reading unit 20, and is closed to press the document during copying. When performing this opening / closing operation, the user places his / her hand on the opening / closing operation section 3 a of the document holder 3. Since the automatic document feeder 30 is provided in the document holder 3, continuous copying can be performed by placing a plurality of documents here.
[0029]
The opening / closing mechanism 4 is provided with a hinge 40, an engagement member 41, a locking pin 42, and an operation lever 43 that is an operation means of an opening limit setting means.
[0030]
Two hinges 40 are provided, one on each side, between the main body 2 and the document holder 3 on the back side of the image forming apparatus 1. The toggle mechanism described above is incorporated in the hinge 40. Thus, when the document holder 3 is opened to a predetermined angle and then released when the document holder 3 is opened, the document holder 3 opens by itself, reaches the limit, and maintains that state. When the document holder 3 is closed to a different angle from this and the hand is released, the document holder 3 comes into close contact with the upper surface of the main body 2 and is completely closed.
[0031]
An operation lever 43, which is an operation unit of the opening limit setting unit, is provided on a side surface of the image forming apparatus 1 with the vicinity of the hinge 40 as a fulcrum and the front side of the image forming apparatus 1 as a free end. The engagement member 41 has a plate shape, is attached to a shaft 43 a at a fulcrum of the operation lever 43, and engages with a locking pin 42 provided on a side surface of the document holder 3. The engagement member 41 plays a role as opening limit setting means.
[0032]
Here, when the angle of the operation lever 43 is changed up and down (arrow B), the angle of the engagement member 41 changes, and the engagement position with the locking pin 42 provided on the document holder 3 changes. Therefore, the opening limit of the document holder 3 can be set by changing the angle of the operation lever 43. The fulcrum of the operation lever 43 has such a frictional force that the angle cannot be easily changed even if the hand is released from the operation lever 43.
[0033]
In this way, the opening limit of the document holder 3 serving as the opening / closing member can be set to a desired angle from the front side of the image forming apparatus 1. As a result, since the user can set the opening limit of the document holder 3 at a desired angle, it is possible to solve the problem that the document holder 3 cannot be reached by the user. In addition, since the user does not need to move to the back side of the image forming apparatus 1 or reach out to set the opening limit of the document holder 3, it is very convenient because it does not require any trouble.
[0034]
Further, the desired opening limit of the document holder 3 can be easily set only by directly changing the angle of the operation lever 43 which is the operating means of the opening limit setting means by hand. As a result, the structure can be simplified and an increase in manufacturing cost can be suppressed.
[0035]
FIG. 2 is a side view of the image forming apparatus according to the second embodiment of the present invention. In the second embodiment, the main body 2 of the image forming apparatus 1 includes a wire 44 as a string member, a rear pulley 45, a front pulley 46, a tension adjustment pulley 47, and a wire feeding amount adjustment member. An operation lever 48 is provided.
[0036]
One end of the wire 44 which is a string-shaped member is connected to the front side of the hinge 40 of the document holder 3 which is an opening / closing member, and the other end is connected to the lowermost end of an operation lever 48 which is a member for adjusting the amount of feeding of the wire 44. ing. The wire 44 is hung between the back side pulley 45 attached to the main body and the front side pulley 46 between the document holder 3 and the operation lever 48. The tension adjusting pulley 47 is attached to the main body 2 via a spring 49, and automatically adjusts the tension of the wire 44.
[0037]
The operation lever 48, which is a member for adjusting the amount of feeding of the wire 44, can rotate forward and backward around a fulcrum 48a within a predetermined angle range. As described above, the wire 44 is connected to the lowermost end of the operation lever 48.
[0038]
In this configuration, the tension point of the wire 44 connected to the document holder 3 is the opening limit of the document holder 3. That is, the wire 44 functions as an opening limit setting unit. Here, when the angle of the operation lever 48 is changed up and down (arrow C), the feeding amount of the wire 44 connected thereto changes, so that the opening limit of the document holder 3 to which the wire 44 is connected can be set (arrow D). ). Therefore, the desired opening limit of the document holder 3 can be easily adjusted only by adjusting the feeding amount of the wire 44 as the string-shaped member by the operation lever 48. The fulcrum 48a of the operation lever 48 has such a frictional force that the angle cannot be easily changed even if the hand is released from the operation lever 48.
[0039]
Note that the wire 44 may be a member made of a material other than metal such as a synthetic fiber as long as the wire is in a string shape.
[0040]
FIG. 3 is a partial cross-sectional side view of an image forming apparatus according to a third embodiment of the present invention. In the third embodiment, similarly to the second embodiment, the knob 49 is set so that the tension point of the wire 44, which is a string-shaped member, is at the limit of opening of the document holder 3, which is an opening / closing member. 1 and is a member for adjusting the amount of feeding of the wire 44. The wire 44 is hung on the pulleys 50 to 52, and a tension adjusting spring 53 is attached between the pulleys 50 and 51.
[0041]
Also in this configuration, when the knob 49 is moved back and forth (arrow E), the feeding amount of the wire 44 changes, and the opening limit of the document holder 3 can be set (arrow F). Therefore, it is possible to easily adjust the opening limit of the desired document holder 3 simply by adjusting the feeding amount of the wire 44 as the string-shaped member by the knob 49 as the feeding amount adjusting member. Note that a frictional force is applied to the mounting portion of the knob 49 such that the knob 49 does not move and stays there even when the hand is released from the knob 49.
[0042]
FIG. 4 is a partial perspective view illustrating a hinge portion of an opening / closing mechanism of an image forming apparatus according to a fourth embodiment of the present invention. In the fourth embodiment, as in the second and third embodiments, the wire 44 is fed out such that the tension point of the wire 44 serving as the string-shaped member is equal to the limit of opening the document press serving as the opening / closing member. Is provided inside the main body 2 below the hinge 40.
[0043]
The drive unit of the electric reel 54 is configured by a stepping motor, and includes an electromagnetic brake for holding rotation when power is turned off (not shown). The operation means of the electric reel 54 is provided on the front side of the image forming apparatus 1 (not shown). This operating means is composed of, for example, a button group in which some opening limits are set in advance, and a numeric keypad for inputting a desired opening limit numerically. The other end of the wire 44 is connected to the document holding side hinge piece 40a.
[0044]
When the user sets the opening limit of the document holder 3 using the operating means provided on the front side of the image forming apparatus 1, the electric reel 54 moves the wire 44 at a predetermined angle based on the setting. (Arrow G in FIG. 4B). Here, when the power supply to the electric reel 54 is stopped, its rotation is held by the electromagnetic brake. Next, when the document holder 3 is opened (the same arrow H), the wire 44 fed from the electric reel 54 is gradually pulled up, and when the wire 44 is in a tension state, the document holder 3 reaches the opening limit.
[0045]
In this way, it is possible to automatically and quickly adjust the feeding amount of the wire 44, which is a string-shaped member. As a result, if a button in which a predetermined opening limit is set in advance as described above is provided as an operation means, the opening limit of the document holder 3 can be set more easily by pressing one of the buttons, The working time can be reduced and the operability can be improved. Further, since it is only necessary to connect the electric reel 54 and its operating means with a signal cable, the opening / closing mechanism 4 can be made more compact.
[0046]
The driving and control of the electric reel 54 may be performed by another member having the same function as that of the stepping motor or the electromagnetic brake. For example, the rotation angle control may be performed by an encoder using a servomotor.
[0047]
FIG. 5 is a main part side view showing an image forming apparatus according to a fifth embodiment of the present invention and an engaging portion of an opening / closing mechanism thereof. In the fifth embodiment, an operation pulley 55, a driven pulley 56, an endless belt 57, and a rack 58 are provided on the main body 2 of the image forming apparatus 1. The driven pulley 56 is provided with a pinion 59 so as to rotate in the same direction as the rotation.
[0048]
An endless belt 57 is hung between an operation pulley 55 attached to the front side of the main body 2 of the image forming apparatus 1 and a driven pulley 56 attached to the back side. The driven pulley 56 is provided with the pinion 59 as described above, and the pinion 59 rotates in the same direction as the driven pulley 56 rotates. Therefore, the operation pulley 55, the driven pulley 56, and the endless belt 57 are the rotation operation members of the pinion 59. A rack 58 meshes with the pinion 59, and the upper end of the rack 58 protrudes from the upper surface of the main body 2 of the image forming apparatus 1. At the upper end of the rack 58, a locking pin 60 is provided, which engages with an engaging member 61 provided on the document holder 3, which is an opening / closing member (see FIG. 5B).
[0049]
According to this configuration, the time when the locking pin 60 of the rack 58 protruding from the main body 2 of the image forming apparatus 1 engages with the engaging member 61 of the document holder 3 is the opening limit of the document holder 3. That is, the rack 58 functions as opening limit setting means. Here, when the operation pulley 55 is rotated back and forth (arrow I), the pinion 59 rotates together with the driven pulley 56 via the endless belt 57, and the amount of protrusion of the rack 58 meshing with the pinion 59 changes (arrow J). The opening limit of the document holder 3 that engages with the rack 58 can be set (arrow K). Therefore, it is possible to easily adjust the opening limit of the desired document holder 3 only by adjusting the amount of projection of the rack 58. It should be noted that a frictional force acts on the shaft of the operation pulley 55 to such an extent that the operation pulley 55 stops without rotating even when the hand is released from the operation pulley 55.
[0050]
Note that the rotating operation member of the pinion 59 does not have to be configured as the above-described two pulleys and the endless belt hung on these two pulleys. For example, the operation pulley may be replaced with an operation member such as a lever. Further, the pinion 59 may be rotated by a motor, and the operation means of the motor may be arranged on the front side of the image forming apparatus. The operating means is composed of, for example, a button group in which some opening limits are set in advance, and a numeric keypad for numerically inputting a desired opening limit.
[0051]
FIG. 6 is a partial perspective view showing a hinge portion of an opening / closing mechanism of an image forming apparatus according to a sixth embodiment of the present invention. In the sixth embodiment, a crank 62, a crank rod 63, and a locking pin 64 are provided at a hinge 40 of the opening / closing mechanism 4.
[0052]
The drive unit of the crank 62 is constituted by a stepping motor, and is provided with an electromagnetic brake for holding rotation when power is turned off (not shown). The crank 62 is provided inside the main body 2 below the hinge 40. The operation means of the crank 62 is provided on the front side of the image forming apparatus 1 (not shown). This operating means is composed of, for example, a button group in which some opening limits are set in advance, and a numeric keypad for inputting a desired opening limit numerically. A crank rod 63 is attached to the crank 62, and the upper portion of the crank rod 63 projects from the upper surface of the main body 2 of the image forming apparatus 1. A groove 63a is provided in the crank rod 63, and a locking pin 64 provided on the document holding side hinge piece 40a is inserted into the groove 63a.
[0053]
When the user sets the opening limit of the document holder 3 using operating means provided on the front side of the image forming apparatus 1, the crank 62 pushes the crank rod 63 at a predetermined angle based on this setting. (Arrow L in FIG. 6B). Here, when the energization of the motor is stopped, the rotation is held by the electromagnetic brake. Next, when the document presser 3 is opened (the same arrow M), the locking pin 64 provided on the document press side hinge piece 40a gradually rises along the groove 63a provided on the crank rod 63, and these are engaged. When the state is matched, the document holder 3 opens and reaches the limit. That is, the crank rod 63 functions as opening limit setting means.
[0054]
In this way, it is possible to easily adjust the desired opening limit of the document holder 3 only by adjusting the amount of projection of the crank rod 63. Further, the protrusion amount of the crank rod 62 can be automatically and quickly adjusted. As a result, if a button in which a predetermined opening limit is set in advance as described above is provided as an operation means, the opening limit of the document holder 3 can be set more easily by pressing one of the buttons, The working time can be reduced and the operability can be improved. Further, since it is only necessary to connect the motor and its operating means with a signal cable, the opening / closing mechanism 4 can be made more compact.
[0055]
The driving and control of the crank 62 may be performed by another member having the same function as that of the stepping motor or the electromagnetic brake. For example, the rotation angle control may be performed by an encoder using a servomotor. Further, the rotating operation of the crank 62 does not necessarily have to be automatically performed by a motor or the like, and as in the fifth embodiment, a rotating operation member such as two pulleys and an endless belt hanging on these pulleys is used. It may be used manually.
[0056]
Although the embodiment of the present invention has been described above, other various modifications can be made without departing from the gist of the present invention. For example, in the first embodiment shown in FIG. 1, the engagement member 41 constituting the opening / closing mechanism 4, the locking pin 42, and the operation lever 43 which is the operation means of the opening limit setting means are provided in the image forming apparatus 1. Although they are provided on the left side, they may be provided on the right side of the image forming apparatus 1. Further, in the second to sixth embodiments, the opening / closing mechanism 4 may be provided at any place such as the left side or the right side of the image forming apparatus 1 or inside the housing of the image forming apparatus 1.
[0057]
【The invention's effect】
According to the configuration of the present invention, the opening limit of the opening / closing member can be set to a desired angle from the front side of the device. As a result, the user himself / herself can set the opening limit of the opening / closing member to a desired angle, thereby making it possible to solve the problem that the user cannot access the opening / closing member. In addition, since the user does not need to move to the back side of the device or reach his hand to set the opening limit of the opening / closing member, it is very convenient because it does not take much time.
[Brief description of the drawings]
FIG. 1 is a top perspective view of an image forming apparatus according to a first embodiment of the present invention; FIG. 2 is a side view of an image forming apparatus according to a second embodiment of the present invention; FIG. FIG. 4 is a partial perspective view showing a hinge part of an opening / closing mechanism of the image forming apparatus according to a fourth embodiment of the present invention; FIG. FIG. 6 is a main part side view showing an image forming apparatus according to a fifth embodiment and an engaging portion of the opening / closing mechanism thereof. FIG. 6 is a view showing a hinge part of the opening / closing mechanism of the image forming apparatus according to a sixth embodiment of the present invention. Perspective view [Description of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Main body 3 Document holder 4 Opening / closing mechanism 40 Hinge 41, 61 Engaging members 42, 60, 64 Locking pins 43, 48 Operating lever 44 Wire 49 Knob 54 Electric reel 58 Rack 59 Pinion 62 Crank 63 Crank rod

Claims (8)

Opening / closing an opening / closing member provided substantially horizontally on the upper surface of a device in a substantially vertical plane using a hinge provided on the back side of the device as a fulcrum, with a hand on a free end located on the front side of the device. In the opening and closing mechanism that can
An opening / closing mechanism comprising: an opening limit setting unit for the opening / closing member; and an operating unit for operating the opening limit setting unit is disposed on a front side of the device. 2. An operation member provided on a side surface of the device, with a fulcrum near the hinge, a front end of the device as a free end, and an opening limit of the opening / closing member set by changing its own angle. 3. The opening and closing mechanism according to claim 1. 2. The device according to claim 1, wherein a tension point of the string member connected to the opening / closing member is a limit of opening of the opening / closing member, and a feeding amount adjusting member of the string member is arranged on a front side of the device. Opening and closing mechanism. 4. The opening / closing mechanism according to claim 3, wherein the string-shaped member is extended from an electric reel, and operation means of the electric reel is arranged on a front side of the device. The point at which the rack projecting from the device engages with the opening / closing member is the opening limit of the opening / closing member, and the pinion rotating operation member for changing the amount of projection of the rack is arranged on the front side of the device. The opening / closing mechanism according to claim 1, wherein: The opening / closing mechanism according to claim 5, wherein the pinion is rotated by a motor, and operating means for the motor is arranged on a front side of the device. The time at which the crank rod projecting from the device engages with the opening / closing member becomes the opening limit of the opening / closing member, and a crank rotation operating member for changing the amount of projection of the crank rod is arranged on the front side of the device. The opening / closing mechanism according to claim 1, wherein: The opening / closing mechanism according to claim 7, wherein the crank is rotated by a motor, and operation means for the motor is arranged on a front side of the device.

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