JP2000142910A - Article elevating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an article elevating device which can allow a pair of article carriers to surely abut against the road surface on which the elevating device is installed, even though the road surface is bumpy more or less, and which can smoothly transfer an article with the use of a hand lifter. SOLUTION: In an article elevating device comprising a pair of article carriers 16 adapted to be elevate between a position on the road surface F side and a position thereabove, a pair of elevatable bodies 34 provided corresponding respectively to the article carriers 16, for supporting the article carriers 16 and moving them up and down, and an elevation drive means for driving, for elevation, the pair of elevatable bodies 34 in a synchronized condition so as to elevate the pair of article carriers 16 while the they are held at substantially the same height, the pair of carriers 16 are supported respectively to the associated elevatable bodies 34 so as to be unmovable downward relative to each other but movable upward relative to each other, and when the pair of article carriers 16 are lowered to the road surface F side, they abut against the road surface F so as to check and regulate the lower limit thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pair of article supports which are vertically moved up and down over a roadside position and a position above the roadside, and each of the article supports is individually corresponding to each of the article supports. Provided, a pair of elevating bodies that support the article support and move up and down, and the pair of elevating bodies are moved up and down while maintaining the same or substantially the same height. The present invention relates to an article lifting / lowering apparatus provided with lifting / lowering driving means for vertically lifting / lowering in synchronization.

[0002]

2. Description of the Related Art An article elevating apparatus having such a configuration is used in an automatic warehouse or the like. An article is placed between a pair of article supports and driven up and down by an elevating drive means.
The article placed on the article support is raised and lowered. By the way, when it is attempted to transfer an article to the article support of the article elevating apparatus by the hand lifter, the up and down movement of the article by the hand lifter is an extremely limited distance. It is desirable to configure so that it can be transferred in a state where it is located nearby.

Therefore, conventionally, an X-shaped link rotatably and pivotally connected by a pin is located below a pair of elevating frames functioning as an elevating body, and the link and the elevating frame are linked and connected. By rotating the pair of helical shafts in a synchronized state, the lifting frame is raised and lowered via the X-shaped link, and the article supports are fixed to the inside of the pair of lifting frames, respectively. In addition, there has been proposed a configuration in which the pair of article supports are extended to below the lifting frame so that the pair of article supports can be stopped in a state where the pair of article supports are in contact with a road surface (for example, Japanese Unexamined Patent Application Publication No. No. 9-12284).

[0004]

However, according to the above-mentioned publication, if the road surface on which the elevating device is installed is flush with the whole surface, the pair of article supports are brought into contact with the road surface together. Although it can be stopped, there is a problem that if the road surface on which the elevating device is installed has irregularities, the pair of article supports cannot be brought into contact with the road surface.
That is, since the article supports are respectively fixed to the pair of lifting frames, if there is unevenness on the road surface, one of the article supports comes into contact with the road surface first and stops, and the other article support is stopped. You will stop when your body is lifted off the road.

Therefore, when an article is to be transferred while moving a hand lifter on a road surface on which an elevating device is installed, the article is placed in an inclined state with respect to a pair of article supports, or There is a problem that it is difficult to insert the fork of the hand lifter into a desired position with respect to the article on the article support, and there is a disadvantage that the article cannot be smoothly transferred by the hand lifter.

The present invention focuses on such a conventional problem. The object of the present invention is to ensure that a pair of article supports can be securely connected to a road surface even if there is some unevenness on the road surface on which the elevating device is installed. It is an object of the present invention to provide an article lifting / lowering device which can be stopped by contacting the upper side thereof, whereby the article can be smoothly transferred by a hand lifter.

[0007]

According to the first aspect of the present invention, each of a pair of article supports has a lower relative position with respect to a corresponding elevating body. The pair of article supports are immovably supported so as to be relatively movable upward, and when the pair of article supports is lowered to the road surface side, the lower surface is configured to be received and regulated by contact with the road surface. Because there is unevenness on the road surface,
Even if one article support comes in contact with the road surface first, the lifting body corresponding to that article support moves downward as it is,
After that, the other article support is also brought into contact with the road surface and received, so that regardless of the presence or absence of unevenness on the road surface, the pair of article supports can always be reliably brought into contact with the road surface and stopped. The article transfer operation by the hand lifter, which is performed while moving on the upper side, can be performed smoothly.

According to the second aspect of the present invention, the elevating drive means for vertically driving the pair of elevating bodies drives the respective driving means for vertically elevating the pair of elevating bodies, and operates the driving means in a synchronized state. Since it is composed of the control means, one of the article supports, the corresponding lifting / lowering body and the lifting / lowering driving means can be treated as one unit, and the other can be treated as another unit. Work and the like become easy, but synchronization between the pair of elevating bodies is reliably maintained.

According to the third aspect of the present invention, since the elevating body is constituted by a cord-like body wound in the vertical direction, it is constituted by a telescopic rod-like body such as a cylinder. The structure is simpler and the manufacturing cost is lower than that of the first embodiment.

According to the fourth aspect of the present invention, each of the pair of article supports is formed in a long shape, and both ends of the pair of article supports in the longitudinal direction can be freely moved in the vertical direction. Guide means for guiding and supporting is provided, and the elevating body,
Since it is configured to support the central portion in the longitudinal direction of the article support, only one elevating body is required for each of the pair of article supports, and furthermore, the guide of the guide means at both ends in the longitudinal direction. In operation, each article support can be raised and lowered smoothly without any twisting.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an article lifting / lowering apparatus according to the present invention will be described with reference to the drawings. Such an article elevating apparatus is used for an automatic warehouse or the like, and as shown in FIGS. 1 and 2, an article storage shelf 2 provided with a plurality of article storage units 1 in a vertical direction and a horizontal direction is connected to each other. A pair of rails 3 for a stacker crane are laid in a straight line on the floor F between the paired article storage shelves 2 with the fronts facing each other. A stacker crane 4 that moves along the rail 3 is provided so as to be able to automatically travel along the frontage of the article storage shelf 2. The stacker crane 4 is provided with an elevating platform 5 which can be raised and lowered in the vertical direction, and the elevating platform 5 expands and contracts toward the article storage unit 1 located on both sides, and a pallet P on which an article A is placed.
Is provided with a fork-type transfer device 6 for transferring the pallets P together.

On one side of the carry-in / out side of the article storage shelf 2, a pair of right and left relay truck rails 7 are laid in a straight line on the floor F in a state parallel to the stacker crane rails 3. A relay truck 8 that automatically travels on the pair of left and right rails 7 is provided, and the relay truck 8 is configured to reciprocate between a shelf-side transfer position X and an external-side transfer position Y. I have. The relay truck 8 includes a pair of left and right drive wheels 9 and a free wheel 10 that rolls on a pair of left and right rails 7, and the traveling electric motor 1 for driving the drive wheels 9 to rotate forward and reverse.
1 are provided, and at the four corners of the upper surface thereof, an article support table 12 in the form of a fixed pedestal which spreads outward upward and guides and supports the pallet P is provided.

At the shelf-side transfer position X, the fork-type transfer device 6 provided on the stacker crane 4 expands and contracts, and the articles A placed on the article support table 12 of the relay truck 8 are moved. The pallet P is scooped and transferred onto the lift 5 of the stacker crane 4, and thereafter, the self-propelled movement of the stacker crane 4, the vertical movement of the lift 5, and the expansion and contraction of the fork-type transfer device 6, The articles A are placed and carried in the article storage sections 1 of the article storage shelves 2 together with the pallets P, or conversely, the articles A are taken out of the article storage sections 1 and transported. The pallet P is transferred onto the article support table 8 of FIG.

The rail 7 for the relay truck is extended to the side of the control box 13 which is installed substantially at the center of the pair of article storage shelves 2 on the loading / unloading side.
3 is set to the external transfer position Y,
At the outer transfer position Y, there is provided a relay elevating device 14 as an article elevating device that mounts and supports the article A together with the pallet P and moves up and down. As shown in FIG. 3 and FIG. 4, the relay elevating device 14 includes two columns 15 on the left and two columns 15 on the right in a state along the rail 7 when viewed from the direction along the rail 7 for the relay truck. The left and right 2
Article support 1 vertically moving up and down with respect to book support 15
6 are provided. Note that the left and right article supports 16 and the devices attached thereto are selfishly different between the left and right, but structurally, there is almost no change. Only the differences between the left and right structures will be described each time.

As shown in FIG. 9, the two columns 15 have a rectangular cross section and are formed of a hollow metal mold. A mounting base plate 17 is fixed to the lower end thereof. Through the anchor bolt B
And is fixed substantially vertically on a floor surface F as a road surface, and the upper ends thereof are connected to each other by a metal channel-like connecting member 18 arranged in a horizontal direction. Each column 15 is provided with a lifting frame 19 which moves up and down along the longitudinal direction of the column 15, and a plurality of idle-type guide rollers 20 provided on the lifting frame 19 are provided with a column 15 having a rectangular cross section. Rolls in contact with both short side surfaces of the
, A plurality of slide members 21 provided on the support member 15 are configured to contact and slide on the inner side surface of the long side of the column 15,
Both lifting frames 19 that move up and down along the pair of columns 15
The article support 16 described above is attached therebetween.

The article support 16 is formed of a sheet metal so as to be substantially L-shaped in a lateral side view and rectangular in a plan view, that is, an elongated shape. And a support member 15, a lifting frame 19, a guide roller 20, and a slide member 21 at both ends in the longitudinal direction.
The guide means G is configured to be movable in the vertical direction. As shown in FIGS. 5 to 8, a bracket plate 23 is fixed to the longitudinal center rear surface of the article support 16, and a pair of connecting members 24 is fixed to the bracket plate 23. A long connecting hole 25 having a length L1 in the up-down direction is formed in each of the two connecting members 24 so as to face each other.

A pair of brackets 26 are mounted on the upper surface of the connecting member 18 in the longitudinal direction, and bearings 27 are mounted on the respective brackets 26. It is freely held. The two bearings 27 are vertically movably held by bolts 30 inserted into four vertically long holes 29 formed in the bracket 26, and each bearing 27 is screwed to the connecting member 18. Adjustment bolt 31
Is forcibly moved upward. At a lower position corresponding to the idle sprocket 28, a pair of bearings 3 mounted on the base plate 17 is provided.
The drive sprocket 33 is rotatably held by the drive sprocket 2, and one endless chain 34 as a cord is wound around the drive sprocket 33 and the upper idle sprocket 28. Thus, the chain 34 is configured to be able to remove slack and apply a constant tension.

A connecting block 35 is interposed on the inner side of the endless chain 34, and connecting pins 36 are provided from both sides of the connecting block 35.
Are projected, and each connecting pin 36 is connected to the connecting member 2.
4 is inserted into a long connecting hole 25 formed in the hole. Then, the drive sprocket 33 is rotationally driven by a lifting / lowering electric motor 37 with a speed reducer as a driving means provided on the base plate 17, and the connection block 35 is moved upward with the movement of the chain 34. The two connecting pins 36 are configured to contact the upper ends of the two connecting long holes 25 to raise the article support 16. In addition, when the electric motor 37 for raising and lowering is reversely driven to move the connecting block 35 downward along with the movement of the chain 34, the article support 16 is lowered and the article support 16 is placed on the floor F. The connecting pin 36 is configured to be able to move downward in the connecting long hole 25 even in the contact state, so that the article support 16 is brought into contact with the floor surface F.

That is, the chain 34 functions as an elevating body that supports the article support 16 and moves up and down.
The connecting pin 36 of the connecting block 35 and the connecting member 24
Each article support 16 is formed by a connection slot 25 formed in
Are supported with respect to each chain 34 by disabling relative movement downward and allowing relative movement upward, and each article support 16 is brought into contact with the floor F by The descending range is configured to be received and regulated.

In the vertical movement path of the connecting block 35, a limit switch bracket 38 for restricting the downward movement of the connecting block 35 is located near the lower moving path. Installed. The limit switch bracket 38 includes a lowering limit switch 40 having an idler roller 40a, and an emergency stop lower limit switch 41 having an idler roller 41a. It is attached to the chain 34 with its position shifted vertically in a state where it is located above and with a length L2 shorter than the length L1 of the connecting long hole 25 therebetween. The connection block 35 is provided with a dog 42 which comes into contact with the idle rollers 40a, 41a of the limit switches 40, 41. Although not shown,
In the vicinity of the movement path above the connecting block 35, a limit switch for ascending limit and an upper limit switch for emergency stop similar to the lowering limit switch 40 and the lower limit switch 41 for emergency stop are provided. The dog 42 is also configured to be able to contact the idle roller of the switch.

The motor shaft 45 of the elevating electric motor 37 with the speed reducer extends beyond the driving sprocket 33 attached to the motor shaft 45 to the opposite side of the elevating electric motor 37, and its extending end. The disk 46 is attached to the portion, and the disk 46 is configured to rotate integrally with the motor shaft 45. As shown in FIG. 10, the outer periphery of the disk 46 is cut off at two places, and teeth 46 a and portions 46 b without teeth are alternately located on the outer periphery of the disk 46. It is configured as follows. Then, a horseshoe-shaped photo sensor 47 for detecting the tooth portion 46a and the toothless portion 46b of the disk 46 is disposed so as to straddle the disk 46,
The photo sensor 47 is fixedly held by a bracket 48 attached to the base plate 17, and turns on when the photo sensor 47 detects the tooth portion 46a and turns off when it detects the toothless portion 46b with the rotation of the disk 46, and the pulse is turned on. Is configured to occur.

As shown in FIG. 1 and FIG. 2, of both sides along the movement path of the relay truck 8, both sides of the outer transfer position Y are formed by a back plate 49 of the relay lifting device 14. On the side opposite to the control box 13, the wire mesh 50 is covered with the shelf-side transfer position X, and on the control box 13 side, the shelf-side transfer position X is set. The wire nets 50 are provided in a state where they are removed, respectively, and the relay truck 8 and the article A on the relay truck 8 are provided by the back plate 49 of the relay lifting device 14 and the guard member 51 composed of the wire mesh 50.
It is configured to cover the side surface. In other words, at the shelf-side transfer position X, the fork-type transfer device 6 of the stacker crane 4 transfers the articles from the side on the control box 13 side to the relay truck 8, and the outer-side transfer position Y
Is configured to transfer articles to the relay lifting device 14 from the front along the relay bogie rail 7, and the other side of the moving path of the relay bogie 8 is a guard member 5.
1 and the rear side of the shelf-side transfer position X is an article storage shelf 2
It is a configuration covered by

The operation of the automatic warehouse having such a configuration is entirely controlled by the control device H as control means using a microcomputer housed in the control box 13, and is also stored in the article storage shelf 2. Goods A
Is managing. Therefore, this control device H
As shown in the figure, the control device for the stacker crane that controls the stacker crane 4 and the control device for the relay truck that controls the relay truck 8 are configured to be able to communicate with each other, and are provided on the upper surface of the control box 13. Operating device and an operating panel 52 provided on the relay elevating device 14 (see FIG. 2).
Are configured to control various devices based on an operation command from
And the detection information of the photo sensor 47 and the like are all input.

Next, the control operation of the automatic warehouse by the control device H will be described. When storing the article A in the article management shelf 2, the fork 53 a of the hand lifter 53 is inserted into the fork insertion hole of the pallet P on which the stored article A is placed, and the article A is transferred by the hand lifter 53 to the relay lifting / lowering device 1.
4 and is operated by operating an operating device provided on the upper surface of the control box 13 to input necessary information on the stored article A. Then, based on the input information, the control device H selects the article storage shelf 2 that stores the article A and the article storage unit 1. Before and after the operation of the operating device, the stored articles A are placed by the hand lifter 53 together with the pallets P on the left and right article supports 16 of the relay lifting device 14. The mounting operation of the article A by the hand lifter 53 is performed by the two article supports 16 as described in detail later.
Since it is in contact with the floor F, the pallet P
Does not need to be raised very much and can be placed relatively easily.

When the placement on the article support 16 is completed, the hand lifter 53 is retracted, and when the start of operation is instructed by the operation panel 52 provided in the relay elevating device 14,
The left and right elevating electric motors 37 are driven synchronously. In other words, in order to raise and lower the pair of article supports 16 while maintaining the pair of article supports 16 at substantially the same height, the raising and lowering drive unit that drives the pair of chains 34 in a synchronized state by the raising and lowering electric motor 37 and the controller H is used. With the movement of the chain 34 due to the rotation of the drive sprocket 33, the connecting block 3
5 is moved upward, and both connecting pins 36 are connected to the connecting member 2.
4 is in contact with the upper surface of the long connecting hole 25. When the connecting block 35 is moved upward as it is, the left and right article supports 16 are lifted and rise in synchronization with each other, and in conjunction with the rise of the article supports 16, the relay cart 8 is moved.
The driving electric motor 11 is driven, and the trolley 8 moves to the outside transfer position Y side along the rail 7.

Dog 42 provided on connecting block 35
However, when it comes into contact with the idler roller of the limit switch (not shown), the electric motor 37 for lifting and lowering is stopped, and the left and right article supports 16 are stopped at predetermined upper positions. While the article support 16 is being lifted, the control device H compares the pulses from the left and right photosensors 47, and if there is a deviation of more than a fixed amount between both pulses, that is, for some reason, the left and right When the article support 16 stops rising at the same speed, an alarm device (not shown) is activated to stop the article support 16 from rising. And, despite that the dog 42 contacts the idle roller of the limit switch for ascending restriction,
When the lifting electric motor 37 does not stop, the control device H activates an alarm device and activates the lifting electric motor 37 with the contact of the upper limit switch for emergency stop of the dog 42 with the idle roller. To stop.

When the left and right article supports 16 stop at a predetermined upper position, the relay truck 8 enters below the pallet P raised by the article support 16 and receives a predetermined value based on information from a sensor (not shown). The pallet P is lowered together with the article support 16 by the reverse rotation of the electric motor 37 for elevating and lowering, and the controller H compares the pulses from the left and right photosensors 47 during the lowering. are doing. As shown in FIG. 4, the relationship between the article support 16 and the article support 12 is such that the length of the article support 16 in the front-rear direction is longer than the distance between the pair of article supports 12 positioned in the front-rear direction. Since it is configured to be short and to enter inside between the pair of front and rear article support tables 12, the four corners of the pallet P are guided by the article support table 12 of the relay truck 8 as the article support 16 descends. Thus, the article support 16 is placed and held on the article support base 12, and the article support 16 is lowered as it is. Thereafter, the dog 42 of the connection block 35 is moved to the idle roller 40 a of the lowering limit switch 40. By contact, the lifting electric motor 37 stops.

When the electric motor 37 for lifting and lowering is stopped by the information from the lowering limit switch 40, the connecting pin 36 of the connecting block 35 is connected to the connecting member 24.
Is set in advance so as to be located below and apart from the upper surface of the connection long hole 25 formed in the floor, so that even if the floor surface F has some irregularities, the left and right article supports 16 are surely secured to the floor surface. It stops at the lower position where it is in contact with F. When the electric motor 37 for lifting and lowering is not stopped by the information from the lowering limit switch 40, the control device is brought into contact with the emergency stop lower limit switch 41 of the dog 42 against the idle roller 41a. H activates the alarm device to stop the electric motor 37 for elevating. At that time, the connecting slot 25
The length L2 between the limit switches 40 and 41 is shorter than the length L1, and the connecting pin 36 is set so as not to contact the lower surface of the connecting long hole 25. The emergency stop is performed before the connecting pin 36 comes into contact with the lower surface of the connecting long hole 25.

The relay truck 8 on which the article A is placed and held together with the pallet P is moved to the shelf-side transfer position X by the reverse rotation of the electric motor 11 for traveling, and based on information from a sensor (not shown). It stops at a predetermined shelf side transfer position X. When the relay truck 8 stops, the fork-type transfer device 6 of the stacker crane 4 that has been waiting extends to below the pallet P, and as the elevator 5 rises, the article A is scooped together with the pallet P. In addition, the article A is transferred together with the pallet P onto the elevator 5 by the retreat of the fork-type transfer device 6.
Then, by the self-propelled movement of the stacker crane 4, the elevation of the elevating platform 5, and the expansion and contraction operation of the fork-type transfer device 6, the articles A are stored in the article storage unit 1 of the selected article storage rack 2.
Then, the loading operation of the article A is completed after being placed and stored together with the pallet P.

When the article A is carried out, necessary information on the article A to be carried out is input by the operating device. Then, based on the input information, the control device H selects the article storage shelf 2 in which the articles A to be carried out are stored and the article storage section 1, and, contrary to the above-described carrying-in work, the stacker crane 4 Then, the article A is carried out together with the pallet P from the selected article storage unit 1 and is placed on the article support table 12 of the relay truck 8 at the shelf-side transfer position X. Then, the relay truck 8
The traveling electric motor 11 is driven to move the relay cart 8 to the external transfer position Y side, and the lifting electric motor 3
7 is also driven, and the article support 16 waiting on the floor F in contact with the floor F starts to rise.

In synchronization with the stop of the relay truck 8 at the predetermined external transfer position Y, the rising article support 16 moves the article A
The trolley 8 is returned to the original shelf-side transfer position X, and the dog 42 of the connecting block 35 is brought into contact with the idler roller of the limit switch for ascending. Stop rising as you do,
It is lowered by the reverse rotation drive of the lifting electric motor 37. As described above, the dog 42 of the connecting block 35 is moved downward by the lowering limit switch 40.
As it comes into contact with the idler roller 40a, it stops in a state where it is securely in contact with the floor surface F. Thereafter, the article support 16
The fork 53a of the hand lifter 53 is inserted into the fork insertion hole of the pallet P
To transport the article A together with the pallet P to a predetermined location, and the work of unloading the article A ends.

[Other Embodiments] (1) In the above-described embodiment, an example is shown in which a pair of chains 34 as an elevating body is provided with an electric motor 37 for elevating and lowering which constitutes an elevating driving means. , A pair of chains 34
Can be linked to one common electric motor 37 for raising and lowering, so that both chains 34 can be driven up and down in synchronization with each other.

(2) In the above embodiment, an example in which the chain 34 is used as the elevating member has been described. However, the elevating member may be configured by a rack, and the rack may be configured to be moved up and down by rotation of a pinion. In addition, the elevating body can be configured by using a telescopic cylinder.

(3) In the above embodiment, the article support 16
The configuration in which both ends in the longitudinal direction are guided and supported by the guide means G, and the central part in the longitudinal direction is supported by the chain 34. Conversely, the central part in the longitudinal direction of the article support 16 is guided by the guide means G. Guide and support, both ends side chain 3
4, the guide means G can be omitted.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of the entire automatic warehouse.

FIG. 2 is a perspective view of a main part of an automatic warehouse.

FIG. 3 is a front view of a relay elevating device.

FIG. 4 is a side view of the relay lifting device.

FIG. 5 is a front view of a main part of the relay elevating device.

FIG. 6 is a front view of a main part of the relay elevating device.

FIG. 7 is a plan view of a main part of the relay elevating device.

FIG. 8 is an exploded perspective view of a main part of the relay elevating device.

FIG. 9 is a plan view of a main part of the relay elevating device.

FIG. 10 is a front view of a main part of the relay elevating device.

FIG. 11 is a block diagram showing a control device.

[Explanation of symbols]

 Reference Signs List 14 Article lifting device 16 Article supporting body 34 Cable-like body as lifting body 37 Driving means constituting lifting driving means A Article F Road surface G Guide means H Control means configuring lifting driving means

Claims (4)

[Claims] 1. A pair of article supports which are vertically moved up and down over a position on a road surface side and a position above the road surface, and the article articles are provided separately for each of the article supports. A pair of elevating bodies that support the support and move up and down, and the pair of elevating bodies are driven up and down in synchronization with each other so that the pair of article supports are moved up and down while maintaining the same or substantially the same height. An article elevating device provided with an elevating drive means, wherein each of the pair of article supports is relatively immovable downward and relatively movable upward relative to the corresponding elevating body. An article lifting / lowering device configured to be supported by the apparatus and configured to receive and regulate a lowering range by contact with a road surface when the pair of article supports is lowered to a road surface side. 2. The article according to claim 1, wherein said lifting drive means comprises: a drive means for individually driving the pair of lifting and lowering members, and a control means for operating the drive means in a synchronized state. lift device. 3. The article lifting / lowering apparatus according to claim 1, wherein the lifting / lowering body is a cord-like body wound in a vertical direction. 4. A pair of article supports each having an elongated shape, and a guide means for guiding and supporting the longitudinal ends of each of the pair of article supports so as to be movable in the vertical direction. The lifting body is configured to support a central portion in the longitudinal direction of the article support.
The article lifting / lowering apparatus according to any one of claims 1 to 6.