JP2013234494A - Opening and closing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening and closing device which is provided with a lateral displacement preventing member, can reduce a width dimension of a case and achieve compactification and cost reduction.SOLUTION: A torque transmission shaft 17 for transmitting a torque to a shaft 6 is connected to the shaft 6 so as to rotate around a rotation center line 6a of the shaft 6. Both ends of the torque transmission shaft 17 are projected from both end surfaces of the shaft 6. Both ends of the torque transmission shaft 17 are each rotatably mounted to a bearing member 22 mounted to a bracket 21 fixed to a skeleton 14 of a building. The end surface of the shaft 6 is arranged so as to be located closer to the center of an opening part than the inner bottom surface 5e of a guide rail 5. A lateral displacement preventing member 41, which restricts the lateral displacement of an opening/closing body wound up by the shaft 6, is mounted to the shaft 6 so as to be located in flush with the inner bottom surface 5e of the guide rail 5 and at a position with a distance X from the end surface of the shaft 6 in a direction along the rotation center line 6a of the shaft 6.

Description

  The present invention relates to an opening / closing device provided with a lateral displacement prevention member at the end of a shaft for preventing lateral displacement of an opening / closing body such as a shutter curtain wound around a shaft.

  A shutter curtain as an opening / closing body is mounted on a shaft so that the shutter curtain can be wound and unwound, and the shutter curtain is wound and unwound while being guided by guide rails at both ends. The rotational force transmission shaft that transmits rotational force to the shaft is connected to the shaft so as to rotate about the rotational center line of the shaft, and both ends of the rotational force transmission shaft protrude from both ends of the shaft, and the rotation A disk shape as a side slip prevention part that is rotatably attached to a bearing member attached to a bracket fixed to the building's housing at both ends of the force transmission shaft and regulates the side slip of the shutter curtain wound around the shaft The member is fixed around the rotational force transmission shaft so that it is flush with the inner bottom surface of the guide rail. It is known configuration of the shutter device (see Patent Document 1 for example).

JP 2010-156115 A

However, in the above-described conventional opening / closing device, the lateral slip prevention portion is fixed around the rotational force transmission shaft so as to be positioned on the same plane as the inner bottom surface of the guide rail.
Therefore, as shown in FIG. 4 (the parts corresponding to the components shown in FIG. 2 described later in FIG. 4 are given the same reference numerals), the movement in the direction along the axis of the rotational force transmission shaft 17 is performed. A shaft movement restricting member 23 called a collar for restricting the rotation is provided on the peripheral surface of the rotational force transmitting shaft 17 located between the bearing member 22 attached to the bracket 21 fixed to the housing 14 and the lateral slip prevention member 41. The dimension of the interval Y between the bracket 21 and the lateral slip prevention member 41 must be fixed, and the thickness dimension of the bearing member 22 in the direction along the rotation center line 6a of the shaft 6 + the shaft movement restriction. Since the thickness of the member 23 must be larger than the thickness of the shaft 6 along the rotation center line 6a, the width of the case 2 of the shutter device becomes large. Further, the thickness dimension in the direction along the rotation center line 6a of the shaft 6 is increased, resulting in an increase in cost.
The present invention provides an opening / closing device provided with a lateral slip prevention member, which can reduce the width of the case, can be made compact, and can be reduced in cost.

An opening / closing apparatus according to the present invention is an opening / closing apparatus in which an opening / closing body is attached to a shaft so that the opening / closing body can be wound and unwound, and the opening / closing body opens and closes by being wound and unwound while being guided by guide rails at both ends. A rotational force transmission shaft that transmits rotational force to the shaft is connected to the shaft so as to rotate about a rotational center line of the shaft, and both ends of the rotational force transmission shaft protrude from both end surfaces of the shaft, Both ends of the rotational force transmission shaft are rotatably attached to a bearing member attached to a bracket fixed to a housing of a building, and the end surface of the shaft is located at the center of the opening rather than the inner bottom surface position of the guide rail A lateral slip prevention member that is installed so as to come close to the shaft and regulates lateral displacement of the opening / closing body wound around the shaft is the guide rail. It is located on the same plane as the inner bottom surface or at a position closer to the center of the opening than the inner bottom surface position of the guide rail and at a distance in the direction along the end surface of the shaft and the rotation center line of the shaft. Thus, it is attached to the shaft.
The interval is set in the direction along the rotation center line of the shaft in the shaft movement restricting member that is attached to the peripheral surface of the torque transmission shaft and regulates movement in the direction along the shaft of the torque transmission shaft. It is also characterized by being formed at an interval larger than the thickness dimension.
The lateral slip prevention member is also attached to the peripheral surface of the shaft via a connecting member.
The lateral shift prevention member is also characterized in that it is formed by a disc having a through hole through which the rotational force transmission shaft passes.

According to the opening / closing apparatus according to the present invention, the lateral slip prevention member is mounted on the shaft so as to be positioned at a distance from the end surface of the shaft, thereby being located inside the lateral slip prevention member and between the spacings. Since the shaft movement restricting member and the bearing member can be arranged on the peripheral surface of the rotational force transmission shaft, the width of the case can be reduced in the switchgear provided with the lateral slip prevention member, and the size can be reduced and the cost can be reduced. A switchgear can be provided.
Since the distance is formed at a distance larger than the thickness dimension of the shaft movement restricting member attached to the peripheral surface of the rotational force transmission shaft, the axial movement restriction is performed on the peripheral surface of the rotational force transmission shaft located between the distances. Since the members can be arranged, in the opening / closing device provided with the lateral slip prevention member, the length of the shaft and the sleeve size of the case of the opening / closing device can be reduced, and the opening / closing device can be provided which can be made compact and reduced in cost.
Since the lateral slip prevention member is attached to the peripheral surface of the shaft via a connecting member, the interval can be easily formed.
Since the lateral displacement prevention member is formed by a disc having a through hole in the center, lateral displacement of each slat member of the shutter curtain as an opening / closing body can be regulated.

The perspective view which shows the shutter apparatus by embodiment. The figure which looked at the composition of the shutter device by the embodiment except a shutter curtain from the upper part in a case (part cross section). The perspective view which shows the lateral slip | shift prevention means by embodiment. The figure which looked at the composition of the conventional shutter device except a shutter curtain from the upper part in a case (part cross section).

  As shown in FIG. 1, a shutter device 1 as an opening / closing device includes a shutter case (hereinafter abbreviated as a case) 2 as an opening / closing body housing case, an opening / closing mechanism 3, a shutter curtain 4 as an opening / closing body, a guide rail 5, and a lateral displacement. The prevention means 40 (refer FIG. 2) is provided. 1 and 4, the configuration around the shaft 6 is shown as a cross-sectional view on one side with the rotation center line 6 a of the shaft 6 as a boundary, and the other side is shown as an external view.

The case 2 is formed by a box that houses the opening / closing mechanism 3 and the shutter curtain 4, and is fixed to a building housing 14 located above the opening 13 of the building by a fixing tool such as an anchor bolt or fixing means such as welding. Is done.
The guide rails 5; 5 are members for guiding the side ends 4a; 4a (both ends) of the shutter curtain 4 that open and close the opening 13, and are separated from each other in the opening width direction (left-right direction) of the opening 13. The guide grooves 5a and 5a are provided respectively so as to stand on the left and right sides of the opening 13 and extend in the vertical direction of the opening 13. The guide rails 5; 5 are fixed to the housing 14 via a fixing member (not shown).
The left and right side ends 4a; 4a of the shutter curtain 4 which are both ends in the longitudinal direction of the slat member 10a in the shutter curtain 4 pass through the guide grooves 5a; 5a opposite to each other in the guide rail 5; The shutter curtain 4 moves up and down to open and close the opening 13 by being guided in the up and down direction, which is the opening and closing direction. That is, the shutter curtain 4 of the shutter device 1 is wound around the shaft 6 to open the opening 13 of the building, and the shutter curtain 4 is unwound from the shaft 6 (unwinded) to close the opening 13. .

The shutter curtain 4 includes a slat 10, a drainer 11, and a suspension base 12, and is formed of a metal such as steel.
The slat 10 is formed by a plurality of slat members 10a. The slat member 10a is formed by a long member that is long in a direction along a rotation center line 6a of the shaft 6 described later. The slats 10 have both longitudinal positions of adjacent slat members 10a such that the plurality of slat members 10a are continuous in a direction orthogonal to the longitudinal direction of the slat members 10a (the direction along the long side of the slat members 10a). And the long sides are connected to each other by an engaging portion (not shown) and formed into a rectangular plate shape that can be bent at the connecting portion.
The drainer 11 is connected to the long side of the slat member 10a positioned at one end of the slat 10 in the direction orthogonal to the longitudinal direction of the slat member 10a, and the suspension base 12 is in the direction orthogonal to the longitudinal direction of the slat member 10a. It is connected to the long side of the slat member 10a located at the other end.
The drainer 11 is formed by a long member having a reverse T-shaped cross section that is long in the direction along the center line 6a of the winding shaft 6 and perpendicular to the longitudinal direction (the direction along the long side of the drainer 11). The portion corresponding to the lateral side of the inverted T-shaped cross section located at the lower end is the horizontal portion 11b. The length in the longitudinal direction of the drainer 11 is shorter than the length in the longitudinal direction of the slat member 10a, and the center position in the longitudinal direction of the drainer 11 is aligned with the center position in the longitudinal direction of the slat member 10a. The long side of the vertical part 11a and the long side of the slat member 10a positioned at one end of the slat 10 are connected to each other by an engaging part (not shown).
The suspension base 12 is a connecting member provided intermittently along the long side of the slat member 10a located at the other end of the slat 10, and is positioned above the opening 13 of the building as will be described later. The shutter 2 is connected to the shaft 6 via an outlet hole (not shown) of the shutter curtain 4 in the case 2 fixed to the casing 14.

  The opening / closing mechanism 3 provided in the case 2 includes a shaft 6 on which the shutter curtain 4 is mounted so that the shutter curtain 4 can be wound and unwound, and a rotation driving mechanism 15 that rotates the shaft 6 around the rotation center line 6a of the shaft 6 ( 2).

  The rotation drive mechanism 15 supports a rotation drive source 16 such as a motor, a rotation force transmission shaft 17; 17 called a core that transmits the rotation force to the shaft 6, and a rotation force transmission shaft 17; A mechanism 18 and a power transmission mechanism 19 that transmits the rotational driving force of the rotational driving source 16 to one rotational force transmission shaft 17 are provided.

  The support mechanism 18 includes brackets 21; 21 fixed to the housing 14 so as to be positioned at both ends of the shaft 6, bearing members 22; 22 attached to the brackets 21; 21, and the rotational force transmission shaft 17. And a shaft movement restricting member 23 for restricting movement in the direction along the rotation center line 6a. The shaft movement restricting member 23 includes a cylindrical member 24 having a through-hole through which the rotational force transmission shaft 17 passes in the center, and a fixing bolt 25 as a fixing means for fixing the cylindrical member to the rotational force transmission shaft 17. And is fixed to the outer peripheral surface of one rotational force transmission shaft 17 positioned between one end surface 6x of the shaft 6 and the bearing member 22, and is in contact with one end surface of the shaft 6 or the bearing member 22. Thus, the movement in the direction along the axis of the rotational force transmission shaft 17 is restricted.

The shaft 6 is formed of, for example, a hollow circular steel pipe. The rotational force transmission shafts 17 and 17 are provided at both ends of the shaft 6, and are connected to the shaft 6 by the connecting member 26 inside the shaft 6 so as to protrude from both ends of the shaft 6. The rotational force transmission shaft 17 is constituted by, for example, a circular steel rod having a smaller diameter than the inner diameter of the circular steel pipe constituting the shaft 6. That is, the rotational force transmission shaft 17 and the shaft 6 are provided coaxially so that the rotational center line 6 a of the rotational force transmission shaft 17 and the rotational center line 6 a of the shaft 6 coincide with each other. The rotational force transmission shaft 17 and the shaft 6 are connected via a connecting member 26 by fixing means such as welding or screwing so as to rotate about the rotation center line 6a. In addition, the opening material of the both ends of the circular steel pipe which is the both ends of the shaft 6 has the through-hole which penetrates the rotational force transmission shaft 17, and the lid | cover material which closes the opening of the both ends of the said shaft is attached. The outer surface forms the end surface of the shaft 6.
Then, one rotational force transmission shaft 17 projecting from one end surface 6x of the shaft 6 is rotatably supported by one bearing member 22, and the other rotational force transmission shaft 17 projecting from the other end surface 6y of the shaft 6 is the other. The bearing member 22 is rotatably supported.

  The power transmission mechanism 19 projects from one end face 6 x of the shaft 6 and passes through one bearing member 22. The power transmission mechanism 19 is attached to the end of one rotational force transmission shaft 17 and the rotation of the rotational drive source 16. A drive-side sprocket 29 attached to the output shaft 16a and a roller chain 30 spanned between the drive-side sprocket 29 and the passive-side sprocket wheel 28 are provided, and the rotational force from the rotational drive source 16 is applied to the rotational output shaft 16a. Are transmitted to one of the rotational force transmission shafts 17 via the drive side sprocket 29, the roller chain 30, and the passive side sprocket wheel 28, and the rotational force transmission shafts 17; 17 are supported by the bearing members 22; , The shaft 6 coupled to the rotational force transmission shaft 17; 17 rotates the rotational center line 6a. Rotate as mind.

The lateral displacement prevention means 40; 40 provided on both ends of the shaft 6 include lateral displacement prevention members 41 and connecting members 42 for connecting the lateral displacement prevention members 41 to the outer peripheral surface 6f of the end portion of the shaft 6, respectively.
The lateral slip prevention member 41 is formed of, for example, a disc having a through hole 47 at the center.
The diameter of the through hole 47 of the disk forming the lateral displacement prevention member 41 is such that the rotational force transmission shaft 17 passes through the through hole of the cylindrical member 24 of the shaft movement restricting member 23 and the fixing bolt 25 is loosened. The fixing bolt 25 protruding from the outer periphery of the cylindrical member 24 is formed to have a size larger than twice the length dimension b1 + cylindrical outer peripheral radius dimension b2 (that is, 2 (b1 + b2)). Therefore, the shaft movement restricting member 23 mounted on the peripheral surface of the one rotational force transmission shaft 17 can pass through the through hole 47 of the lateral deviation preventing member 41, and the shaft movement restricting member 23 is installed inside the through hole 47. It becomes possible.
The outer peripheral diameter of the disc forming the lateral slip prevention member 41 is formed to be larger than the outer peripheral diameter of the shaft 6, and the diameter of the through hole 47 is formed to be larger than the outer peripheral diameter of the shaft 6. Therefore, the lateral displacement prevention member 41 comes into contact with the left and right side edges of the shutter curtain 4 wound around the shaft 6, and the lateral displacement of the shutter curtain 4 can be reliably controlled.

In the connecting member 42, the disc surface 43 of the lateral displacement prevention member 41 and the one end surface 6x of the shaft 6 are parallel, and the distance X between the disc surface 43 of the lateral displacement prevention member 41 and the one end surface 6x of the shaft 6 is axially moved. This is a member for attaching the lateral displacement prevention member 41 to the outer peripheral surface 6f of the shaft 6 so as to be larger than the thickness dimension a2 in the direction along the rotation center line 6a of the shaft 6 of the regulating member 23.
The connecting member 42 is, for example, a shaft side flat plate portion 45 fixed to the outer peripheral surface 6f of the shaft 6 by fixing means such as welding or screwing, and one end of the shaft side flat plate portion 45 to the shaft side flat plate portion 45. It is constituted by a so-called angle fitting having an L-shaped cross section, which is provided with a disk side flat plate portion 46 that extends vertically and is fixed to the disk surface 43 of the lateral slip prevention member 41 by fixing means such as welding or screwing. (See FIG. 3).
The discs constituting the lateral slip prevention member 41 are connected to the outer peripheral surface 6f of the shaft 6 by the connecting member 42 at several positions on the circumference of the disc surface 43 centered on the center of the disc at a predetermined angle. Fixed. For example, it is fixed to the outer peripheral surface 6f of the shaft 6 by the connecting member 42 at four positions, for example, 90 ° apart from each other on the circumference of the disc surface 43 centered on the center of the disc.

  That is, the lateral displacement prevention means 40 is not configured in such a manner that a disc as the lateral displacement prevention member 41 is directly attached to the shaft 6, but between the disc surface 43 of the disc of the lateral displacement prevention member 41 and one end surface 6 x of the shaft 6. In addition, in order to form an interval X larger than the thickness dimension a2 in the direction along the rotation center line 6a of the shaft 6 in the shaft movement restricting member 23 attached to the peripheral surface of the rotational force transmission shaft 17, a lateral slip prevention member is formed. 41 is the structure attached to the outer peripheral surface 6f of the shaft 6 via the connection member 42. FIG.

According to the embodiment, the one disk surface 43 serving as the lateral displacement regulating surface of the lateral displacement preventing member 41 facing the one end surface 6x of the shaft 6 and the inner bottom surface 5e of the guide rail 5 are positioned on the same plane, and the shaft 6 is installed so that both ends of the guide rail 5 are closer to the center of the opening portion 13 than the inner bottom surface 5e of the guide rail 5, and the lateral displacement prevention member 41 and the outer peripheral surface of the end portion of the shaft 6 are connected by the connecting member 42. Since the gap X having a dimension larger than the thickness dimension a2 of the shaft movement regulating member 23 is formed between the disc surface 43 serving as the lateral deviation regulating surface of the lateral deviation preventing member 41 and the end surface of the shaft 6, The shaft movement restricting member 23 can be disposed on the inner surface of the lateral displacement preventing member 41 and on the peripheral surface of the rotational force transmitting shaft 17 located between the intervals X. Therefore, the dimension of the interval Y between the bracket 21 and the lateral displacement prevention member 41 is set to the thickness dimension a1 of the bearing member 22 in the direction along the rotation center line 6a of the shaft 6 + the rotation center of the shaft 6 in the shaft movement restricting member 23. Since it can be made smaller than the thickness dimension a2 in the direction along the line 6a, the overall length of the steel pipe of the shaft 6 can be shortened, and the one disc surface 43 of the lateral slip prevention member 41 and the bracket 21 can be shortened by the shortened length. Since the facing distance Y can be shortened and the width dimension of the case 2 can be reduced by the shortened distance, the shutter apparatus having the same opening width dimension as the conventional shutter apparatus shown in FIG. In this case, the case 2 can be downsized and the cost can be reduced.
In other words, according to the embodiment, the sleeve dimension a of the shutter device 1 can be reduced. In the case of the conventional configuration shown in FIG. 4, the sleeve dimension a is the distance between the side surface 2X of the case 2 and the one end surface 6x of the shaft 6 + the depth dimension of the guide rail 5. Compared with the conventional configuration shown in FIG. 4, the sleeve dimension “a” can be shortened by the distance X between the disc surface 43 of the lateral deviation preventing member 41 and the one end surface 6 x of the shaft 6. If the sleeve dimension a can be shortened, there is an effect that the fit (installability) of the case 2 with respect to the building is improved.

Further, by disposing the shaft movement restricting member 23 on the inner surface of the through-hole 47 of the lateral deviation preventing member 41 and on the peripheral surface of the one rotational force transmission shaft 17 located between the intervals X, the sleeve size compared to the conventional configuration. a can be shortened, and movement in the direction along the axis of the rotational force transmission shaft 17 can be restricted.
In FIG. 2, an example in which two shaft movement restricting members 23; 23 are arranged side by side on the inner surface of the through hole 47 of the lateral shift prevention member 41 and the circumferential surface of one of the rotational force transmission shafts 17 located between the intervals X. Is shown. Thus, by arranging the plurality of shaft movement restricting members 23 on the inner surface of the through hole 47 of the lateral shift prevention member 41 and the circumferential surface of the one rotational force transmission shaft 17 located between the intervals X, the rotational force transmission shaft is arranged. Since the movement allowable range in the direction along the axis 17 can be made as small as possible, a high-quality rotation support mechanism for the torque transmission shaft 17 can be configured.
In addition, as shown in FIG. 2, it is preferable that a part of the bearing member 22 is positioned inside the through hole 47 of the lateral shift prevention member 41 because the sleeve dimension a can be further shortened.

  Further, since the lateral slip prevention member 41 is attached to the outer peripheral surface 6f of the shaft 6 via the connecting member 42, the interval X can be easily formed. The lateral displacement prevention member 41 may be attached to the inner peripheral surface of the shaft 6 via the connecting member 42.

  Further, the lateral displacement of the shutter curtain 4 may occur for each slat member 10a. However, as described above, the lateral displacement prevention member 41 is formed of a disk, so that the shutter wound around the shaft 6 is used. Even when the slat members 10a of the curtain 4 individually cause lateral displacement, the lateral displacement of each slat member 10a can be regulated by the lateral displacement prevention member 41.

Further, since the lateral slip prevention means 40 is provided on both end sides of the shaft 6, it is possible to prevent both lateral slips of the shutter curtain 4 wound around the shaft 6.
Note that the lateral slip prevention means 40 may be provided only on one end side of the shaft 6, and the lateral slip prevention member 41 having the configuration shown in FIG. 4 may be provided on the other end side of the shaft 6.

  It should be noted that the disc surface 43 serving as the restricting surface of the lateral deviation prevention member 41 may be installed so as to be closer to the center of the opening 13 than the inner bottom surface 5 e of the guide rail 5. In this way, since the sleeve dimension a can be further reduced, the case 2 can be further downsized.

Moreover, although the example using the disc with a hole in which the through-hole 47 was formed in the center was shown as the lateral slip prevention member 41, the lateral slip prevention member 41 is connected to the shaft by the connecting member 42 so as to form the interval X. 6 and a part of the shaft movement restricting member 23 and the bearing member 22 can be arranged on the inner surface of the lateral slip prevention member 41 and on the circumferential surface of the rotational force transmission shaft 17 located between the intervals X. What is necessary is just to be comprised.
For example, when a disc with a through-hole 47 is used as the lateral displacement prevention member 41, the rotational force transmission shaft 17 must be passed through the disc through-hole 47, so that the disc cannot be retrofitted. Therefore, by using a lateral displacement prevention member 41 that can be attached later (for example, a semicircular shape) in which a disk is divided so that it can be attached to the rotational force transmission shaft 17 from a direction intersecting the rotational force transmission shaft 17. Also good.

  In the above description, the electric shutter device has been described as an example, but the present invention can also be applied to a manual shutter device.

  When the opening / closing body of the opening / closing device to which the present invention is applied is the shutter curtain 4, the configuration is not limited to a mode in which a plurality of so-called slats are arranged in the vertical direction, but also a pipe, a panel, a sheet-like object, or a net. A shutter curtain having an aspect in which one or a plurality of objects are continuously provided, or a shutter curtain in which slats, panels, pipes, sheets, and nets are appropriately combined may be used. The present invention can also be applied to a so-called overhead type shutter curtain.

  The present invention can also be applied to an opening / closing device such as a blind, a roll screen device, and a smoke proof curtain provided with a guide rail, the opening / closing body being guided by the guide rail.

4 Shutter curtain (opening and closing body),
5 guide rail, 5e inner bottom surface of guide rail, 6 shaft, 6a rotation center line,
13 opening, 14 housing, 17 rotational force transmission shaft,
21 Bracket, 22 Bearing member, 23 Axial movement restricting member, 41 Side slip prevention member,
42 connecting member, 47 through-hole.

Claims (4)

In the opening and closing device that opens and closes the opening by winding and unwinding the opening and closing body is attached to the shaft so that it can be wound and unwound, and the both ends of the opening and closing body are guided by the guide rail,
A rotational force transmission shaft for transmitting rotational force to the shaft is connected to the shaft so as to rotate about the rotational center line of the shaft, and both ends of the rotational force transmission shaft protrude from both end surfaces of the shaft, Both ends of the rotational force transmission shaft are rotatably attached to bearing members attached to brackets fixed to the building frame,
The shaft end surface is installed so as to be closer to the center of the opening than the inner bottom surface position of the guide rail,
A lateral slip prevention member that regulates lateral slip of the opening / closing body wound around the shaft is on the same plane as the inner bottom surface of the guide rail or at a position closer to the center of the opening than the inner bottom surface position of the guide rail, The switchgear is attached to the shaft so as to be positioned at an interval in the direction along the end surface of the shaft and the rotation center line of the shaft.   The interval is set in the direction along the rotation center line of the shaft in the shaft movement restricting member that is attached to the peripheral surface of the torque transmission shaft and regulates movement in the direction along the shaft of the torque transmission shaft. The switchgear according to claim 1, wherein the switchgear is formed at an interval larger than a thickness dimension.   The switchgear according to claim 1 or 2, wherein the lateral slip prevention member is attached to a peripheral surface of the shaft via a connecting member.   4. The switchgear according to claim 1, wherein the lateral slip prevention member is formed by a disc having a through hole that allows the rotational force transmission shaft to pass through in the center. 5.

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