JP2783931B2 - Floppy disk transport and recovery device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floppy disk transport device, that is, an autoloader for a floppy disk.
More specifically, the floppy disks stacked in the hopper are sent one by one to a floppy disk drive, and the floppy disks are read by the drive to read data.
It is transported to a predetermined position for writing or copying, etc., and then a suitable floppy disk on which proper reading, writing or copying has been completed, and a suitable reading, writing or The present invention relates to a floppy disk transport / recovery device that identifies an improper floppy disk on which copying or the like cannot be performed, and separates and collects each floppy disk into an appropriate floppy disk storage location and an inappropriate floppy disk storage location.

[0002]

2. Description of the Related Art As a floppy disk transfer device or autoloader used for reading, writing or copying operations of a floppy disk, a clamp which operates in the front-rear direction by passing below a hopper accommodating the floppy disks in a stacked state. When the clamp advances toward the floppy disk drive mechanism, the clamp pushes out the lowest disk of the floppy disk housed in the hopper to the drive mechanism, and completes the copying operation and the like. There is known a structure in which a floppy disk is grasped by the clamp, and the disk is taken out of a drive mechanism and transported so as to drop into a predetermined storage portion (Japanese Patent Application Laid-Open No. 60-50781).
issue).

Further, the floppy disk which is further conveyed toward the drive mechanism side and is conveyed from the drive mechanism toward the collection section after the copying operation or the like is completed is not brought into contact with another floppy disk remaining in the hopper. The floppy disks having been copied are pushed up sequentially from below into a storage section, ie, a stacker, which is installed above the transport passage, and the floppy disks are stored in a stacked state, and the disk generated at the time of transport or collection is removed. There is also known a floppy disk transporting device for preventing damage (JP-A-63-160056).

[0004]

Problems to be Solved by the Invention JP-A-60-5078
In the floppy disk transport device according to No. 1, the floppy disks pushed and run from the hopper come into contact with the lowermost floppy disks stacked in the hopper, so that the floppy disks rub against each other. There was a problem that there was a risk of damaging the disk.

On the other hand, in the floppy disk transport device disclosed in Japanese Patent Application Laid-Open No. 63-160056, the floppy disks for which copying has been completed are sequentially pushed up from the lower part of the stacker and accommodated therein, so that the order of the floppy disks set in the hopper and the stacker There was a problem that the order of the floppy disks stored in the storage was reversed. Therefore, when different types of floppy disks are read, it is necessary to rearrange the floppy disks. Furthermore, since the hopper and the stacker are arranged side by side in a plane, there is a problem that the size of the entire apparatus, particularly the dimension in the depth direction, becomes extremely large.

Further, in these known floppy disk transport devices, a proper floppy disk having no data failure or the like from among the floppy disks stacked in the hopper and an improper one which cannot be read due to a scratch or a defective input. It is not possible to discriminate and collect these floppy disks separately and collect them separately.Therefore, the floppy disks recovered in the stacker after reading or copying work will have the correct floppy disk and the incorrect floppy disk. Was miscellaneously accommodated, and subsequent processing was difficult.

[0007]

SUMMARY OF THE INVENTION In order to solve such problems, the present invention takes out a floppy disk stacked on a hopper from a lower portion and discharges the floppy disk downward from the hopper. From a floppy disk drive to be transported to the floppy disk drive, a floppy disk discharge position identification device to sort the floppy disks that have completed the work with the floppy disk drive, and a stacker to individually drop and collect the separated floppy disks. Means.

[0008]

According to the means of the present invention, the apparatus for discharging a floppy disk from the hopper completely separates the floppy disks stacked in the hopper one by one and supplies the floppy disks to the floppy disk drive. In this way, the discharge device works to completely prevent the rubbing between the floppy disks. The floppy disks stacked on the hopper are taken out from the lower part, and then discharged to a stacker disposed below the hopper and collected. Thus, in the present invention, the floppy disks are moved only from the top to the bottom, so that the stacking order of the floppy disks does not change. In addition, the stackers are arranged side by side on the front of the apparatus so as to reduce the size of the entire apparatus. In addition, the floppy disk ejection location device acts to distribute the floppy disks by angle control, thereby facilitating further processing of the floppy disks.

[0009]

1 is a schematic side view of a floppy disk transport device 10 according to the present invention. This transfer device 10
A hopper 14 for accommodating a known floppy disk 12 as shown in FIG. 8, a known floppy disk drive device 16 for performing operations such as reading, writing or copying of data, and a sheet supplied from the hopper 14 one by one. The floppy disk drive device 18 which transports the floppy disk 12 to the floppy disk drive device 16 and receives the floppy disk 12 therefrom after a predetermined operation such as reading and copying, and discharges it to the stacker. A floppy disk ejection position specifying device 20 for confirming whether or not the work has been properly performed by an error message or the like and specifying the discharge position of the floppy disk 12 accordingly;
The first stacker 22, which collects only the floppy disk on which the appropriate read / write copying operation has been completed, and the adjacent first stacker 22, as shown in FIG. Missing Floppy Disk 12
And a second stacker 24 that houses only the second stacker 24.

As shown in FIGS. 5 and 6, the hopper 14 has an entire upper surface and a part of the front surface (left side in FIGS. 1 and 6) in an open state, so that the floppy disk 12 can be freely moved. It can be supplied into the hopper 14 one by one or in a stacked state. As shown in FIGS. 5 and 6, the floppy disk 12 supplied into the hopper 14 is formed by a pair of chucks 30, a holder plate 32, and an inward bent portion 34 provided at the lower end of the front wall of the hopper. 14.

That is, the rear surface of the hopper 14 (FIGS. 1 and 6)
A motor 36 is disposed on the right side in FIG. The motor 36 rotates an eccentric cam 40 via a gear box 38. The eccentric cam 40 has a pin 42.
The pin 42 rotates in a hole 46 provided at the center of a fixing plate 44 (FIGS. 6 and 7) fixed to the rear wall of the hopper 14. A pair of grooves 48 extending in the front-rear direction is formed on both sides of the hole 46 provided in the fixing plate 44. Pins 50 (FIG. 5) are slidably received in these grooves 48. The lower end of the pin 50 is fixed to the holder plate 32, and the upper end of the pin 50 is
2 (FIG. 5), the chuck 30 is slidably received and held in an elongated hole 54 provided at one end of the chuck 30 rotatably attached to the fixed plate 44. Note that the chuck 3
The other end of the disk 0 has a floppy disk 12 as shown in FIG.
The distal end portion 55 that enters the pair of recesses 13 provided near both sides of the front end portion is fixed by screws 57 as shown in FIG. Further, an elongated hole 56 is provided at the center of the holder plate 32 disposed below the fixing plate 44 so as to slidably receive the lower end of the eccentric pin 42 and extend in the left-right direction. . A pair of floppy disk receiving pieces 58 which are bent forward are provided at the front portion of the holder plate 32. On one side in front of the hopper 14, an alarm device 60 is provided for notifying an operator of an error in setting the floppy disk 12 when the floppy disk 12 is set in the hopper. Therefore, the corner 15 of the floppy disk 12 (FIG. 8) is always located at the rear right portion A (FIG. 5) of the hopper 14.

When the pin 42 is at the position shown in FIG. 5, since the holder plate 32 is drawn most toward the hopper 14, the floppy disk receiving piece 58 of the holder plate 32 is moved toward the hopper 14 as shown by a broken line in FIG. Is inside. On the other hand, the tip portion 55 of the chuck 30 is
, And is located outside the hopper 14 as shown by the solid line in FIG. For this reason, as shown in FIG. 6, the lowermost floppy disk 12a of the laminated floppy disks stacked in the hopper 14 by the operator has a bent portion 34 and a holder plate 32.
The front and rear portions thereof are supported by the floppy disk receiving piece 58 of the present embodiment, and the floppy disks are held in the hopper 14 in a stacked state.

When the motor 36 rotates and the eccentric pin 42 moves in the hole 46 of the fixing plate 44, the holder plate 32 starts moving backward in the direction away from the hopper 14 with the movement of the pin 42. . Holder plate 3
The pin 50 starts moving backward in the groove 48 with the backward movement of the second. Further, as the pin 50 moves backward, the chuck 30 rotates around the pin 52, and the tip 55 of the chuck 30 moves from the solid line position in FIG.
It comes into the position of 4. And hopper 14
Disk receiving piece 5 of the holder plate 32 holding the lowermost floppy disk 12a in the inside.
Before the disk 8 is completely disengaged from the lowermost floppy disk 12a, the tip 55 of the chuck 30 is moved to a position above the lowermost floppy disk 12a.
Of the floppy disk 12b is held in the hopper 14. For this reason,
Further, the motor 36 rotates to move the eccentric pin 42 to the rearmost part of the hole 46, the floppy disk receiving piece 58 of the holder plate 32 is completely removed from the inside of the hopper 14, and the lowermost floppy disk 12a is
Even if the floppy disk stacked in the hopper does not fall from the hopper, the whole floppy disk does not fall from the hopper.

When the eccentric pin 42 is further rotated, the holder plate 32 moves to a position shown by a broken line in FIG. 5 on the hopper 14 side, and the distal end 55 of the chuck 30 moves from a position shown by a broken line in FIG. Move outward from the inside of the hopper 14 to the position indicated by. For this reason, the floppy disk 12b in the hopper 14
Of the holder plate 32 waiting just below, and held by the bent portion 34 and the floppy disk receiving piece 58 of the holder plate 32. Thereafter, the floppy disks housed in the hopper 14 are separated from the hopper 14 one by one and fall by the same procedure. The position of the holder plate 32 can be detected by a sensor (not shown) in which the rising member 33 attached to the holder plate is fixed at a predetermined position.
The presence of the floppy disk 12 in the hopper 14 is detected by the sensor 49.

Below the hopper 14, a pair of floppy disk receiving members 62 are arranged as shown in FIG. The receiving member 62 has rail portions 64 extending in the longitudinal direction on both left and right sides, and each is fixed to the left and right sheet metals. The distance between the left and right rail portions 64 is slightly larger than the width of the floppy disk 12, or the side wall of the rail portion 64 extends upward, and the floppy disk 12 falling from the hopper 14 It is easy to accept.

Thus, the floppy disks 12 supplied one by one from the hopper 14 are reliably received by the upper surface of the rail portion 64 of the receiving member 62.

The floppy disk 12 received by the receiving member 62 is then driven by the floppy disk drive 18.

The floppy disk drive device 18 grips the right and left portions of the trailing edge of the floppy disk 12 received by the receiving member 62, supplies it to the floppy disk drive device 16, and performs predetermined operations by the device 16. Again, the floppy disk 12
And take it out of the device 16 and pull it back to the position where it is released to the stacker.

The floppy disk drive 18 is a pair of left and right devices connected to each other by a carriage plate 19 (FIG. 3). However, since both the left and right devices have the same configuration, the following description will focus on one side. Only the device will be described. This floppy disk drive 18
As shown in FIG. 1, a carriage 68 moves on a shaft 66 extending in the front-rear direction, a solenoid 70 fixed to the carriage 68 and moving with the carriage, a spring 73, and a solenoid 70 together with an elastic load by the spring. A catch lever 72 receiving a linear load due to
An elbow member 74 having an L-shape, one end of which supports one end of a spring 73, the other end of which is rotatably supported by a catch lever 72, and an intermediate portion attached to a solenoid 70.

When the floppy disk 12 is supplied to the rail portion 64 of the floppy disk receiving member 62, the sensor 67 senses the supply of the floppy disk 12, and the stepping motor 76 shown in FIG. The carriage 68 moves to the floppy disk receiving member 62 side (the right side in FIG. 1 and the left side in FIG. 2) via the timing belt 78. At this time, the solenoid 70 is in the operating state and the catch lever 7
2 is downward as shown by the solid line in FIG. Therefore, the front end of the catch lever 72 moves along the rail portion 64 along the rear end of the floppy disk 12 on the rail portion 64 of the floppy disk receiving member 62, and then moves to the position shown by the solid line in FIG. Guide table 90 (see FIG. 10)
Along the rail portion 91 of the floppy disk 12
To a predetermined position inside the known floppy disk drive device 16 against the spring force in the device 16. Immediately after the catch lever 72 pushes the floppy disk 12 into the device 16, the solenoid 70 is deenergized, and the catch lever 72 assumes an upward position as shown by a broken line in FIG. To stop. The deenergization of the solenoid 70 can be achieved by the action of a sensor (not shown). In the floppy disk drive 16, the floppy disk 12
A predetermined operation such as reading or copying is performed.

When the operation by the floppy disk drive device 16 is completed, the floppy disk discharge position specifying device 20 starts operating. As shown in FIG. 3, the floppy disk ejection position specifying device 20 includes a reversible rotatable motor 80 fixed to a frame, and one-way clutches 82 and 83, which rotate in opposite directions to each other, on a drive shaft driven by the motor 80. , A substantially elliptical eject cam 84 and a cam plate 92 having a complicated shape, a substantially U-shaped floppy disk guide table 90 (FIG. 10), and a cam plate 92 and a floppy disk guide. And an eject link 94 connecting a rising portion 96 rising from the front end portion of the table 90.

When the completion of the operation in the floppy disk drive 16 is notified to the motor 80, the motor 8
0 starts the rotation operation in one direction (for example, clockwise). Due to this rotation operation, after the eject cam 84 is rotated by about 180 degrees from a solid line position which is long in the vertical direction in the direction of arrow a in FIG. The position of the motor 8 is sensed.
0 and the rotation of the eject cam 84 are stopped. The eject cam 84 pushes the reset switch 86 of the floppy disk drive 16 to the position shown by the broken line in FIG. 1 when it reaches the position shown by the broken line in FIG. For this reason, the floppy disk 12 in the device 16 is ejected from the device 16. The ejected floppy disk 12 enters the lower side of the catch lever 72 located at the upward position shown by the broken line in FIG. Thereafter, the operation of the sensor 87 (FIG. 1) activates the solenoid 70 to lower the catch lever 72, and thus the catch lever 72 grips the floppy disk 12. Next, when the stepping motor 76 (FIG. 2) rotates in the opposite direction (for example, counterclockwise), the catch lever 72 pulls the floppy disk 12 back from the floppy disk drive device 16 to the intermediate position in FIG. Thereafter, the motor 80 rotates in the opposite direction, and rotates the cam plate 92 in the direction of arrow b. The cam plate 92
Causes the eject link 94 to rotate the floppy disk guide table 90. The floppy disk guide table 90 has a rear end held by a frame by a rotating shaft 95 and a front end attached to an eject link 94 via an upper end of a rising portion 96. A portion that responds to the sensors 98 and 99 and a portion that does not respond are provided around the cam plate 92. This cam plate 92 is used for the device 1
Information on whether or not the work such as reading / writing or copying in 6 has been properly performed is received from the command host in advance by an error message or the like using a known electric or magnetic signal, and in response to this signal, 92 is two sensors 9
Rotation to a specific angle by the interaction of 8,99. The position sensors 100 and 101 shown in FIG.

When the catch lever 72 moves the floppy disk 12 pulled out of the apparatus 16 to the intermediate position in FIG. 1, that is, the floppy disk 12 is moved to a position on the rail portion 91 of the floppy disk guide table 90, the timing belt 78 (FIG. 2) once stops at that position. Next, the cam plate 92 rotates to the aforementioned predetermined position. Therefore, the eject link 94 rotates the floppy disk guide table 90 around the rotation axis 95 until a predetermined angle is reached. Next, the solenoid 70 is deenergized and the pulled-out floppy disk 12 is moved to the rail portion 9.
Leave on 1.

If the floppy disk guide table 9
When 0 is inclined to the first angular position T _1, floppy disk 12 slides the rail portion 91, sequentially are stacked therein falls into it in the first stacker 22 via the fixed stacker table 102. On the other hand, if the floppy disk guide table 90 is tilted to the _second angular position T2 due to an error message or the like, the floppy disk 12 slides on the rail portion 91 and the back of the first stacker 22 via the movable stacker table 104. (FIG. 11). At this time, the motor 106 is driven by the operation of the sensor. Therefore, the pinion 108 rotates, and the rack 110 screwed to the pinion 108 and fixed to the back side of the movable stacker table 104 moves from the first stacker 22 to the second stacker 24 in FIG. At this time, the floppy disk 12 housed and held on the movable stacker table 104 moves rightward on the slider rail 112 together with the movable stacker table 104 while sliding on the back surface of the first stacker 22 (see the broken line 116 in FIG. 11). . The floppy disk 12 in the movable stacker table 104 moves away from the back of the first stacker 22,
When the floppy disk 12 reaches the upper portion of the second stacker lower than the stacker 22, the floppy disk 12 falls from the movable stacker table 104 into the second stacker 24 and is sequentially stacked there, while the movement of the movable stacker table 104 stops. The movement position of the rack 110 is the sensor 11
4 (FIG. 1), and after releasing the floppy disk 12 to the second stacker 24, the movable stacker table 104 is immediately returned to the initial position. Of course, Stacker 2
Conversely, the floppy disks stored in the second and fourth stackers 24 and 24 can store the floppy disk in which the first stacker 22 has generated an error message and the second stacker 24 in which no error message has been generated. is there.

As shown in FIG. 11, the stackers 22 and 24 are arranged side by side on the front or front side of the floppy disk carrier 10, and the first stacker 22 is longer than the second stacker 24 as described above. Is high. Also, the upper surface is open so that the floppy disk 12 can be freely dropped therein and accommodated therein. Further, a front plate 118 is provided on one side of the front surface of the stacker so as to prevent the falling floppy disk 12 from jumping out of the stacker upon dropping. Since the floppy disk 12 directly collides with the discs 118, the paddle 118 is lined with rubber or other shock absorbing material or made entirely of such a material so that the floppy disk 12 is not damaged by the collision. . The floppy disks stacked and accommodated in each of the stackers 22 and 24 are sequentially inserted into the gap 120 on the side of the plate by a predetermined number of sheets from the front position of the apparatus.
At any time, the device can be easily removed from the device without stopping the operation of the device. More preferably, Stacker 2
At the top of 2, 24, for example, a transmission type optical sensor 121 is provided as a stacker full sensor for confirming that a floppy disk has fallen into each stacker without fail. Thereby, it is possible to reliably know the timing of taking out the floppy disk stored in each stacker.

In order to prevent noise when the floppy disk is dropped and to improve the arrangement of the floppy disks, the contact plate 118 on the front surface of the stacker shown in FIG. 11 is completely removed, and instead, as shown in FIG. A stacker door 122 can be attached to the front portion of the stacker. In the illustrated example, the lower end of a stacker door 122 having a rubber or other shock absorbing material adhered to the inside is rotatably attached to the bottom of the stacker by a hinge 124, and the one-touch type mini-latch device 126 (known per se) is mounted on the upper end. For example, Mini Latch S (167
8) Spacer for TL-231 (1381, 138)
3)) is attached. As a result, when the button 128 attached to the door 122 is pressed, the stacker-door 122 is pressed.
Is engaged with the mini-latch device 126 in the upright position, and when the floppy disk is removed, the button 12
When the stacker 8 is pushed in, the stacker door 122 opens forward in the direction of arrow 129, so that the floppy disk can be easily taken out.
However, the stacker door can be of other types (for example, vertical or horizontal slide type).

[0027] The position of the floppy disk guide table 90 shown in T ₃ than is effectively used to the table 90 to the position in there present invention the largest position or bottom dead center of the tilting of the table 90 .

As described above, in the apparatus 10 of the present invention, the floppy disks 12 stacked in the hopper 14 are separated and supplied one by one to the floppy disk receiving member 62, and the floppy disk drive 18 drives the floppy disks 12 by the floppy disk drive 18. After being transported to the drive device 16 and performing a predetermined operation such as reading or copying in the device 16, the floppy disk 12 having no error message from the device 16 and the floppy disk 12 having the error message are respectively The floppy disks are separated by the floppy disk discharge position specifying device 20, and an appropriate floppy disk and an improper floppy disk are sequentially stacked and accommodated in different stackers 22, 24 adjacent to each other.

[0029]

According to the present invention, first, floppy disks are separated and supplied one by one from a hopper 14 in which the floppy disks 12 are stocked, and the separated floppy disks are transported backward to be read or copied. The hopper 14 is separated if necessary and stored in a first stacker 22 provided below the hopper 14. Further, it can be appropriately accommodated in a second stacker 24 juxtaposed with the first stacker 22. That is, by adopting a three-dimensional structure from the conventional planar structure, the dimensions of the entire device, particularly the depth direction, are significantly reduced, and the installation area is extremely reduced.

Further, the floppy disks 12 housed in the hopper 14 and subjected to necessary treatment are sequentially discharged into the stackers 22 or 24 according to the order of taking out from the hopper 14. For this reason, the order of the floppy disks stacked on the hopper can be obtained as it is in the stacker, and handling is extremely easy.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a floppy disk transport device according to the present invention.

FIG. 2 is a view showing a driving relationship of the floppy disk transport device according to the present invention, and is a side view seen from a side opposite to FIG.

FIG. 3 is a front view showing a floppy disk ejection position specifying device of the floppy disk transport device according to the present invention.

FIG. 4 is a front view showing a first stacker and a second stacker of the floppy disk transport device according to the present invention.

FIG. 5 is a top view of a hopper of the floppy disk transport device according to the present invention.

FIG. 6 is a side view of a hopper of the floppy disk transport device according to the present invention.

FIG. 7 is an exploded perspective view of a floppy disk separation and supply device of the floppy disk transport device according to the present invention.

FIG. 8 is a perspective view of a floppy disk handled by the present invention.

FIG. 9 is a perspective view showing a floppy disk receiving member of the floppy disk transport device according to the present invention.

FIG. 10 is a perspective view showing a floppy disk guide table of the floppy disk transport device according to the present invention.

FIG. 11 is a perspective view showing a stacker for storing a floppy disk of the floppy disk transport device according to the present invention.

FIG. 12 is a front sectional view showing another embodiment of the stacker for storing the floppy disk of the floppy disk transport device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Floppy disk transfer device 12 Floppy disk 14 Hopper 16 Floppy disk drive device 18 Floppy disk drive device 20 Floppy disk discharge position specifying device 22 1st stacker 24 2nd stacker 30 Chuck 32 Holder plate 44 Fixing plate 58 Floppy disk receiving piece 62 Floppy Disk receiving member 68 Carriage 72 Catch lever 78 Timing belt 84 Eject cam 90 Floppy disk guide table 92 Cam plate 94 Eject link 102 Fixed stacker table 104 Movable stacker table 108 Pinion 110 Rack 112 Slider rail 118 This plate 120 Gap 121 Sensor 122 Stacker door

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tohru Sasaki 70 Ishigami Nishi, Masuda-cho, Hiraka-gun, Akita Prefecture Inside Juki Electronics Industry Co., Ltd. (72) Inventor Go Go Honma 70, Ishijin-Nishi, Masuda-cho, Hiraka-gun, Akita Prefecture (56) References JP-A-1-130358 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 17/22-17/30 G11B 15 / 68

Claims (1)

(57) [Claims] 1. A floppy disk stacked on a hopper is sent one by one to a lower floppy disk drive, and the floppy disk is transported by the drive to a floppy disk drive for data reading, writing or copying. Then, an appropriate floppy disk that has been properly read, written, or copied, and an inappropriate floppy disk that has not been properly read, written, or copied due to data failure or damage. Floppy disks are discriminated and discarded, and each floppy disk is separated and collected into an appropriate floppy disk storage location and an inappropriate floppy disk storage location.In a floppy disk transport and recovery device, an appropriate floppy disk and an inappropriate floppy disk Floppy disk to identify release location by sorting A discharge position specifying device 20; and a first stacker 22 disposed below the floppy disk discharge position specifying device 20 for receiving the one of the separated floppy disks sent from the floppy disk discharge position specifying device 20. A second stacker disposed below the floppy disk discharge position specifying device 20 for receiving the other of the separated floppy disks sent from the floppy disk discharge position specifying device 20; It has a second stacker 24 that is shorter than the stacker, and a stacker table 104 that transfers the other of the sorted floppy disks to the second stacker 24. The first stacker 22 and the second stacker 24 are At the front of the floppy disk transport and recovery device, There is no front side wall surrounding the stacker in front of these stackers, and the space 120 is just enough for a finger to enter, and the stacker is sent out from the floppy disk discharge position specifying device 20. A floppy disk transport / recovery device, characterized in that a plate 118 for preventing each floppy disk from jumping out of the space 120 forward of the stacker is provided on the front side wall portion of each stacker.