Shutter opening / closing mechanism of upper conveyer of circulation type grain dryer

Abstract

To provide a shutter opening / closing mechanism of an upper conveyer of a circulation type grain dryer, whose production cost can be suppressed by simplifying the structure thereof relative to conventional structure.SOLUTION: The shutter opening / closing mechanism is characterized by comprising a discharge shutter support arm 551 attached to a discharge shutter 55, a discharge side cam 552 abutting the discharge shutter support arm 551 to open / close the discharge shutter 55, a release shutter support arm 581 attached to a release shutter 58, a release side cam 582 abutting the release shutter support arm 581 to open / close the release shutter 58, and a motor 59 rotating / driving the discharge side cam 552 and the release side cam 582.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a shutter opening and closing mechanism in an upper conveying device of a circulating grain dryer, which enables grain transported by the upper conveying device of a circulating grain dryer to be equally divided into grain storage sections by an equalizer installed at the end of the upper conveying device, or to be fed into the grain storage section without passing through the equalizer, or to be discharged outside the machine from the start end of the upper conveying device. [Background technology]

[0002] Patent Document 1 discloses a circulating grain dryer which has a storage section installed at the top into which grain is stored, a drying section installed below it for drying grain that falls from the storage section, and an elevator connecting the bottom of the drying section to the top of the storage section, in which grain discharged from the bottom of the drying section is lifted by the elevator to the storage section, and circulatory drying is performed until the grain reaches a predetermined moisture content.

[0003] An upper conveying device is hung above the storage section, the start end of the upper conveying device is connected to the upper end of the elevator, and a grain drop port is formed at the end of the upper conveying device. An equalizer is suspended below the grain drop port so that the grain conveyed by the upper conveying device is divided into equal portions and piled up in the grain storage section. In addition, a discharge port that is opened and closed by a switching shutter is provided at the bottom of the start end of the upper conveying device, so that when drying is completed, the switching shutter can be opened and the grain can be removed from the machine through the discharge port.

[0004] When drying rice, wheat, corn, etc., passing the grains through a separator does not cause any particular problems, but when drying beans, buckwheat, etc., using a separator to rotate and disperse the grains will cause them to collide with the surrounding machine walls, resulting in damaged grains. In order to avoid such damaged grains, Patent Document 1 forms a discharge port that opens and closes with a shutter on the bottom surface of the part of the upper conveying device located inside the machine, and when drying beans, buckwheat, etc., the shutter is opened to release the grains from the discharge port into the storage section without passing them through the separator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3512727 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the upper conveying device described in Patent Document 1, the output shafts of the motors are connected to the rotating shaft of the switching shutter that opens and closes the discharge port and the rotating shaft of the shutter that opens and closes the ejection port using a transmission wheel, chain, etc. With this configuration, the switching shutter and the shutter are opened and closed separately, which causes problems such as a large number of parts, a complex structure, a bulky device, and increased manufacturing costs.

[0007] In view of the above-mentioned problems, the present invention aims to provide a shutter opening and closing mechanism for an upper conveying device of a circulating grain dryer, which has a simpler structure than conventional shutter opening and closing mechanisms and reduces manufacturing costs. [Means for solving the problem]

[0008] The present invention comprises a grain storage section for storing grain, a drying section provided below the storage section, and an upper conveying device disposed above the grain storage section and capable of conveying the grain to an equalizer, the upper conveying device comprising a grain drop port for dropping grain into the equalizer, a discharge port for discharging grain outside the machine and a discharge shutter for opening and closing the discharge port, a discharge port between the discharge port and the grain drop port for dropping grain into the grain storage section and a discharge shutter for opening and closing the discharge shutter, and a shutter for opening and closing the discharge shutter and the discharge shutter. and a shutter opening and closing mechanism in an upper conveying device of a circulating grain dryer, the shutter opening and closing mechanism comprising: a discharge shutter support arm provided on the discharge shutter, a discharge side cam that abuts against the discharge shutter support arm to open and close the discharge shutter, a discharge shutter support arm provided on the discharge shutter, a discharge side cam that abuts against the discharge shutter support arm to open and close the discharge shutter, and a motor that rotates and drives the discharge side cam and the discharge side cam.

[0009] Furthermore, the present invention is characterized in that the shutter opening and closing mechanism has a cam position detection unit that detects the rotational positions of the discharge side cam and the discharge side cam using a plurality of proximity switches, and the motor is controlled based on the detected rotational positions of the discharge side cam and the discharge side cam.

[0010] In a further aspect of the present invention, the motor is a reversible motor. Effect of the Invention

[0011] According to the present invention, the discharge side cam and the discharge side cam that open and close the discharge shutter and the discharge shutter, respectively, can be driven and controlled by a single motor, making it possible to simplify the structure of the shutter opening and closing mechanism compared to conventional methods and reduce manufacturing costs. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of a circulation type grain dryer according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a perspective view of an upper transport device according to the embodiment of the present invention. [Diagram 3] FIG. 2 is a front view of a main part of an upper conveying device according to the embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view of a main part of an upper transport device according to the embodiment of the present invention. [Diagram 5] 1A and 1B show an upper transport device according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional view in a state where a discharge shutter is closed, and FIG. 1B is a cross-sectional view in a state where a discharge shutter is closed. [Figure 6] 1 is a front view of an upper transport device according to an embodiment of the present invention with a discharge shutter and a release shutter closed; [Figure 7] 1A and 1B show an upper transport device according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional view in a state where a discharge shutter is closed, and FIG. 1B is a cross-sectional view in a state where a release shutter is open. [Figure 8] 1 is a front view of an upper transport device according to an embodiment of the present invention with a discharge shutter closed and a release shutter open. [Figure 9] 1A and 1B show an upper transport device according to an embodiment of the present invention, in which FIG. 1A is a cross-sectional view in a state where a discharge shutter is open, and FIG. 1B is a cross-sectional view in a state where a discharge shutter is open. [Figure 10] 1 is a front view of an upper transport device according to an embodiment of the present invention with a discharge shutter and a release shutter both open. FIG. [Figure 11] 1 is a cross-sectional view of a discharge port portion of an upper transport device according to an embodiment of the present invention in a state where a discharge shutter is closed and a motor is locked. [Figure 12] 1 is a cross-sectional view of a discharge port portion of an upper transport device according to an embodiment of the present invention in a state where a discharge shutter is open and a motor is locked. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the embodiment.

[0014] FIG. 1 is a cross-sectional view of a circulation type grain dryer according to an embodiment, FIG. 2 is an oblique view of an upper conveying device according to an embodiment, FIG. 3 is a front view of a main part of the upper conveying device according to an embodiment, FIG. 4 is an oblique view of a main part of the upper conveying device according to an embodiment, FIG. 5 shows an upper conveying device according to an embodiment, where (a) is a cross-sectional view when the discharge shutter is closed and (b) is a cross-sectional view when the discharge shutter is closed, FIG. 6 is a front view of the upper conveying device according to an embodiment with the discharge shutter and the discharge shutter closed, and FIG. 7 shows an upper conveying device according to an embodiment, where (a) is a cross-sectional view when the discharge shutter is closed and (b) is a cross-sectional view when the discharge shutter is open. FIG. 8 is a front view of the upper conveying device of the embodiment with the discharge shutter closed and the discharge shutter open, FIG. 9 shows the upper conveying device of the embodiment, (a) being a cross-sectional view with the discharge shutter open and (b) being a cross-sectional view with the discharge shutter open, FIG. 10 is a front view of the upper conveying device of the embodiment with the discharge shutter open and the discharge shutter open, FIG. 11 is a cross-sectional view of the discharge outlet portion of the upper conveying device of the embodiment with the discharge shutter closed and the motor stopped, and FIG. 12 is a cross-sectional view of the discharge outlet portion of the upper conveying device of the embodiment with the discharge shutter open and the motor stopped.

[0015] A cross-sectional view of a circulation type grain dryer according to an embodiment is shown in Figure 1. As shown in the figure, the circulation type grain dryer 1 includes a grain storage section 2, a drying section 3, a grain lifter 4, and an upper conveying device 5. The grain storage section 2 is installed at the upper part of the circulation type grain dryer 1, and grain to be dried is charged therein.

[0016] The drying section 3 is installed below the grain storage section 2, and uses hot air to dry the grain that flows down from the grain storage section 2. The lifting machine 4 is erected on one side of the circulating grain dryer 1, and its lower end is connected to the end in the conveying direction of the lower conveying device 6 that is arranged at the bottom of the drying section 3. The upper end of the lifting machine 4 opens above the grain storage section 2. The lifting machine 4 lifts the grain that has passed through the drying section 3 and been conveyed by the lower conveying device 6 above the grain storage section 2.

[0017] As shown in Figures 1 and 2, the upper conveying device 5 is formed by housing a screw conveyor 51 inside a conveying gutter 50, and is installed horizontally above the grain storage section 2. A grain supply port 40 formed at the upper end of the grain lifter 4 is connected to the starting end of the upper conveying device 5 in the conveying direction, and grain discharged from the bottom of the drying section 3 is lifted by the grain lifter 4 and supplied to the starting end of the upper conveying device 5. The end of the upper conveying device 5 in the conveying direction reaches the center of the grain storage section 2, where a grain drop port 52 is formed. In addition, an equalizer 53 is suspended below the grain drop port 52.

[0018] Below the grain supply port 40 of the grain lifter 4, a grain discharge port 54 is formed at the bottom of the conveying gutter 50, and a discharge shutter 55 is provided to open and close the discharge port 54. Below the discharge port 54, a discharge chute 56 is installed to send the discharged grain outside the machine, and around the discharge port 54, a discharge port guide slope 540 is provided that is sloped so that its diameter gradually decreases downward.

[0019] In the portion of the upper conveying device 5 located above the grain storage section 2 (the portion between the grain drop port 52 and the discharge port 54), a grain discharge port 57 is formed at the bottom of the conveying gutter 50, and a discharge shutter 58 is provided for opening and closing the discharge port 57. A discharge port guide slope 570 is provided around the discharge port 57, sloped so that the diameter gradually decreases downward.

[0020] As shown in FIG. 5(a), the discharge shutter 55 opens and closes the discharge port 54 by rotating a discharge-side rotating shaft 550 provided along a side edge of the upper transport device 5 parallel to the transport direction about a central axis.

[0021] 5(b), the discharge shutter 58 opens and closes the discharge port 57 by rotating about the central axis of the discharge side rotation shaft 580 provided along the side edge parallel to the conveying direction of the upper conveying device 5. As shown in FIG. 3, the discharge side rotation shaft 550 and the discharge side rotation shaft 580 are not connected to each other and are arranged on a single straight line.

[0022] The discharge shutter 55 and the discharge shutter 58 are opened and closed by a shutter opening and closing mechanism connected to the discharge-side rotating shaft 550 and the discharge-side rotating shaft 580. As shown in Figures 3 and 4, the shutter opening and closing mechanism includes a discharge shutter support arm 551 attached to the discharge-side rotating shaft 550, a discharge shutter support arm 581 attached to the discharge-side rotating shaft 580, a discharge-side cam 552, a discharge-side cam 582, and one motor 59 that drives the discharge-side cam 552 and the discharge-side cam 582 to rotate in both forward and reverse directions.

[0023] The support arm 551 for the discharge shutter extends from the end of the discharge side rotating shaft 550 on the discharge port 57 side, and a first roller 553, which is a cam follower that moves in contact with the outer periphery of the discharge side cam 552, is provided on one surface of the support arm 551 for the discharge shutter.

[0024] The support arm 581 for the discharge shutter extends from the end of the discharge side rotating shaft 580 on the discharge port 54 side, and a second roller 583, which is a cam follower that moves in contact with the outer periphery of the discharge side cam 582, is provided on one surface of the support arm 581 for the discharge shutter.

[0025] The discharge-side cam 552 and the discharge-side cam 582 are arranged parallel to each other and fixed to the outer periphery of the output shaft 590 of the motor 59. As shown in Figures 5, 7 and 9, a proximity switch sensor 591 is provided on the outer periphery of the output shaft 590 of the motor 59, and three proximity switches 592a, 592b, and 592c are installed at positions facing the track of the proximity switch sensor 591. The proximity switch sensor 591 and the proximity switches 592a, 592b, and 592c form a cam position detection unit that detects the positions of the discharge-side cam 552 and the discharge-side cam 582.

[0026] The outer periphery of the discharge-side cam 552 has a large diameter curved portion 5520 that is far from the center of the output shaft 590, a small diameter portion 5521 that is continuous with one side of the large diameter curved portion 5520 and is far from the center of the output shaft 590, a straight portion 5522 that is continuous with one side of the small diameter portion 5521, and a rotation stopper portion 5523 that protrudes from the other end of the large diameter curved portion 5520. In addition, the discharge-side cam 552 is formed with a circular hole 5524 and a recess 5525 for manually rotating the discharge-side cam 552.

[0027] The outer periphery of the discharge side cam 582 has a large diameter portion 5820 that is distant from the center of the output shaft 590, a small diameter curved portion 5821 that is continuous with one side of the large diameter portion 5820 and is distant from the center of the output shaft 590, a straight portion 5822 that is continuous with one side of the small diameter curved portion 5821, and a rotation stopper portion 5823 that protrudes from the other end of the large diameter portion 5820. The discharge side cam 582 also has a circular hole 5824 formed therein for manual rotation operation.

[0028] When drying rice, wheat, corn, etc., the drying of rice, wheat, or corn is selected using an operation panel not shown, which drives motor 59 to rotate discharge side cam 552 and release side cam 582, and motor 59 stops when proximity switch sensor 591 attached to output shaft 590 reaches the position of proximity switch 592a, as shown in Figure 5.

[0029] At this time, as shown in (a) of Figure 5, the first roller 553 provided on the support arm 551 for the discharge shutter comes into contact with and is pressed against the large diameter curved portion 5520 of the discharge side cam 552, and the support arm 551 for the discharge shutter receives a clockwise rotational force around the central axis of the discharge side rotating shaft 550 in the figure, causing the discharge shutter 55 to close.

[0030] Also, as shown in (b) of Figure 5, the second roller 583 provided on the support arm 581 for the release shutter comes into contact with and is pressed against the large diameter portion 5820 of the release side cam 582, and the support arm 581 for the release shutter receives a clockwise rotational force around the central axis of the release side rotation shaft 580 in the figure, causing the release shutter 58 to close.

[0031] Then, as shown in Figure 6, the discharge outlet 54 of the upper conveying device 5 is closed by the discharge shutter 55, and the discharge outlet 57 is closed by the discharge shutter 58, so that the grains (rice, wheat, corn, etc.) supplied from the grain lifter 4 to the starting end of the upper conveying device 5 are transported to the end, fall through the grain drop port 52, and are evenly distributed within the grain storage section 2 by the equalizer 53.

[0032] On the other hand, when drying of beans, buckwheat, etc. is selected on the operation panel, the motor 59 is driven to rotate the discharge side cam 552 and the release side cam 582, and as shown in Figure 7, the motor 59 stops when the proximity switch sensor 591 attached to the output shaft 590 reaches the position of the proximity switch 592b.

[0033] At this time, as shown in (a) of Figure 7, the first roller 553 abuts against and is pressed against the large diameter curved portion 5520 of the discharge side cam 552, and the discharge shutter support arm 551 receives a clockwise rotational force around the central axis of the discharge side rotation shaft 550, causing the discharge shutter 55 to close.

[0034] On the other hand, as shown in FIG. 7(b), the small diameter curved portion 5821 of the discharge side cam 582 reaches the position of the second roller 583, so that the pressing force applied to the second roller 583 disappears and the discharge shutter 58 opens by its own weight.

[0035] As shown in Figure 8, the discharge outlet 54 of the upper conveying device 5 is closed by the discharge shutter 55 and the discharge outlet 57 is opened, so that the grains (beans, buckwheat, etc.) supplied from the grain lifter 4 to the starting end of the upper conveying device 5 are loaded into the grain storage section 2 from the discharge outlet 57, which is located upstream of the grain drop port 52 in the conveying direction, without passing through the equalizer 53.

[0036] When the grains reach a predetermined moisture content, the operator operates the operation panel to discharge the grains, which starts the motor 59 to rotate the discharge side cam 552 and the release side cam 582 in the reverse direction, and when the proximity switch sensor 591 attached to the output shaft 590 reaches the position of the proximity switch 592c as shown in FIG.

[0037] At this time, as shown in FIG. 9(a), the small diameter portion 5521 of the discharge side cam 552 reaches the position of the first roller 553, and the pressing force applied to the first roller 553 disappears, so that the discharge shutter 55 opens by its own weight.

[0038] As shown in FIG. 9B, the position of the second roller 583 coincides with the small diameter curved portion 5821 of the discharge side cam 582, and the second roller 583 is not pressed by the discharge side cam 582, so that the discharge shutter 58 opens by its own weight.

[0039] As shown in Figure 10, the discharge outlet 54 and discharge outlet 57 of the upper conveying device 5 are opened, and the grain that has been dried to a predetermined moisture content and supplied from the lifting machine 4 to the starting end of the upper conveying device 5 falls from the discharge outlet 54 located below the grain supply inlet 40 of the lifting machine 4 and is discharged outside the machine via the discharge chute 56.

[0040] 11, if the proximity switch sensor 591 fails to react and the grain is rotated too far in the direction of stacking the grain in the grain storage section 2, i.e., in the direction of closing the discharge shutter 55, the first roller 553 hits the anti-rotation portion 5523 of the discharge side cam 552 and the motor 59 stops, and as a result, the first roller 553 passes through the large diameter curved portion 5520 of the discharge side cam 552 and the discharge shutter 55 opens, preventing the grain from being discharged outside the machine. Although not shown in the figure, at this time the second roller 583 also hits the anti-rotation portion 5823 of the discharge side cam 582, stopping the motor 59.

[0041] 12, if the proximity switch sensor 591 fails to react and rotates too far in the direction in which the grain is discharged outside the machine, i.e., in the direction in which the discharge shutter 55 opens, the first roller 553 comes into contact with the straight portion 5522 of the discharge side cam 552 and the motor 59 stops. At this time, although not shown, the second roller 583 comes into contact with the straight portion 5822 of the release side cam 582 and stops the motor 59.

[0042] In the event of a breakdown in the motor 59, the discharge side cam 552 is rotated manually by placing fingers in the hole 5524 and the recess 5525, or the discharge side cam 582 is rotated manually by placing fingers in the hole 5824.

[0043] According to the above embodiment, the discharge shutter 55 and the discharge shutter 58 are opened and closed by driving one motor 59 to rotate the discharge side cam 552 and the discharge side cam 582. As a result, depending on the type of grain, the discharge shutter 55 and the discharge shutter 58 can be closed and the grain can be equally divided into the grain storage section 2 by the equalizer 53 provided at the grain drop port 52, or the discharge shutter 55 can be closed and the discharge shutter 58 can be opened to pile the grain into the grain storage section 2 from the discharge port 57 without passing through the equalizer 53. Furthermore, when drying of the grain is completed, the discharge shutter 55 and the discharge shutter 58 can be opened to discharge the grain to the outside of the machine through the discharge port 54.

[0044] The discharge side rotating shaft 550 and the discharge side rotating shaft 580 are arranged on a single straight line, a discharge shutter support arm 551 is provided at the end of the discharge side rotating shaft 550 on the discharge port 57 side, a discharge shutter support arm 581 is provided at the end of the discharge side rotating shaft 580 on the discharge port 54 side, and a discharge side cam 552 that abuts against the discharge shutter support arm 551 and a discharge side cam 582 that abuts against the discharge shutter support arm 581 are attached to an output shaft 590 of a single motor 59. Therefore, the number of parts is significantly reduced compared to the conventional art, and the lengths of the output shaft 590, the discharge shutter support arm 551, and the discharge shutter support arm 581 are short, making the shutter opening and closing mechanism compact, and therefore the manufacturing cost is low.

[0045] The discharge shutter 55 is supported by a discharge shutter support arm 551 provided at the end on the discharge port 57 side, and the discharge shutter 58 is supported by a discharge shutter support arm 581 provided at the end on the discharge port 54 side. As a result, even if the grain being transported by the upper conveying device 5 toward the end is pressed against the closed discharge shutter 55 and discharge shutter 58, the discharge shutter 55 and discharge shutter 58 will not open at the boundary between the discharge port 54 and the discharge port 57, and it is possible to prevent the grain that is piled up and dried in the grain storage section 2 from being accidentally discharged outside the machine.

[0046] (Another embodiment) The present invention is not limited to the above-mentioned embodiment, and may also include the following, for example.

[0047] For example, the shapes of the discharge side cam 552 and the release side cam 582 are not limited to those shown in the figure, so long as they are shapes that open and close the discharge shutter 55 and the release shutter 58 when the first roller 553 and the second roller 583, respectively, move to a specified position.

[0048] In the above-described embodiment, the cam position detection device formed by the proximity switches 592a, 592b, 592c and the proximity switch sensor 591 detects the positions of the discharge-side cam 552 and the discharge-side cam 582 to control the operation of the motor 59, but the positions of the discharge-side cam 552 and the discharge-side cam 582 may be controlled by the operating time set by the motor 59 to open and close the discharge-side cam 552 and the discharge-side cam 582. Alternatively, the positions of the discharge-side cam 552 and the discharge-side cam 582 may be controlled by a stepping motor.

[0049] Although the embodiment and another embodiment of the present invention have been described above, the above-mentioned embodiment of the invention is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention includes equivalents thereof. Furthermore, the components described in the claims and the specification may be combined or omitted within the scope of solving at least part of the above-mentioned problems or achieving at least part of the effects.

[0050] 1 Circulating grain dryer 2 Grain storage section 3 Drying section 4 Grain frying machine 40 Grain Supply Inlet 5. Upper conveyor 50 Conveyor Tunnel 51 Screw Conveyor 52 Grain Drop Hole 53 Equalizer 54 Outlet 540 Discharge port guide inclined part 55 Discharge shutter 550 Discharge side rotating shaft 551 Support arm for ejection shutter 552 Discharge side cam 5520 Large diameter curved section 5521 Small diameter section 5522 Straight section 5523 Anti-rotation part 5524 hole 5525 Recess 553 First Roller 56 Ejection Chute 57 Outlet 570 Outlet guide slope part 58 Emission Shutter 580 Discharge side rotating shaft 581 Support arm for ejection shutter 582 Discharge Cam 5820 Large diameter section 5821 Small diameter curved section 5822 Straight section 5823 Anti-rotation part 5824 hole 583 3rd Roller 59 Motor 590 Output shaft 591 Proximity Switch Sensor 592a, 592b, 592c Proximity Switches 6 Lower conveyor

Claims

1. The grain storage unit includes a grain storage section for storing grain, a drying section provided below the storage section, and an upper conveying device disposed above the grain storage section and capable of conveying the grain to an equalizer. The upper conveying device is A grain drop port through which the grain falls into the equalizer; a discharge port for discharging the grain outside the machine and a discharge shutter for opening and closing the discharge port; a discharge port between the discharge port and the grain drop port for dropping the grain into the grain storage section, and a discharge shutter for opening and closing the discharge port; a shutter opening / closing mechanism that opens and closes the discharge shutter and the release shutter, The shutter opening and closing mechanism includes: The ejection shutter has a support arm for the ejection shutter provided on the ejection shutter, an ejection side cam that contacts the support arm for the ejection shutter to open and close the ejection shutter, a support arm for the ejection shutter provided on the ejection shutter, an ejection side cam that contacts the support arm for the ejection shutter to open and close the ejection shutter, and one motor that rotates and drives the ejection side cam and the ejection side cam. A shutter opening and closing mechanism for an upper conveying device of a circulating grain dryer.

2. The shutter opening and closing mechanism includes: A cam position detector is provided that detects the rotational positions of the discharge side cam and the release side cam using a plurality of proximity switches, and the motor is controlled based on the detected rotational positions of the discharge side cam and the release side cam.

2. A shutter opening / closing mechanism for an upper conveying device of a circulation type grain dryer according to claim 1.

3. The motor is a reversible motor.

3. A shutter opening / closing mechanism for an upper conveying device of a circulation type grain dryer according to claim 1 or 2.

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