Palletized coil transport

Abstract

The present application relates to a kind of tray type steel coil transport device, comprising: double-row narrow roller way, including first heavy roller way and first light roller way, first heavy roller way is located at the side of first light roller way, and height is equivalent, interval is first threshold value;Double-row wide roller way, including second heavy roller way and second light roller way, second heavy roller way is located at the side of second light roller way, and height is equivalent, interval is second threshold value;First rotary roller way is set at the junction of double-row narrow roller way and double-row wide roller way;Wherein, first heavy roller way is connected with second heavy roller way, and height is equivalent, first light roller way is connected with second light roller way by first rotary roller way, and height is equivalent, second threshold value is greater than first threshold value.By the process type of the combination of various roller ways, various difficult situations encountered in the field are solved, so that tray transport system replaces traditional walking beam transport system more efficiently, meets the urgent needs of reconstruction time during annual repair construction.

Description

Technical Field

[0001] This invention relates to the field of steel coil transportation, and in particular to a pallet-type steel coil transportation device. Background Technology

[0002] In the transportation of steel coils in steel rolling mills, traditional walking beam and chain conveyors are gradually being replaced by palletized steel coil transport devices. These retrofit projects are typically completed during annual maintenance periods; however, due to unfavorable on-site factors, the modification of the foundation pit is challenging, and failure to complete it within the stipulated time will affect subsequent production. Summary of the Invention

[0003] Therefore, it is necessary to provide a pallet-type steel coil transport device to address the above problems, adapt to different on-site conditions and requirements, and make pallet-type transport more convenient and efficient than walking beam transport.

[0004] A palletized steel coil transport device, the device comprising:

[0005] The double-row narrow roller conveyor includes a first heavy-load roller conveyor and a first light-load roller conveyor. The first heavy-load roller conveyor is located on one side of the first light-load roller conveyor and has a similar height and a spacing of a first threshold.

[0006] The double-row wide roller conveyor includes a second heavy-load roller conveyor and a second light-load roller conveyor. The second heavy-load roller conveyor is located on one side of the second light-load roller conveyor and has a similar height and a spacing of a second threshold.

[0007] The first rotary roller conveyor is located at the connection between the double-row narrow roller conveyor and the double-row wide roller conveyor;

[0008] The first heavy-load roller conveyor is connected to the second heavy-load roller conveyor and has a similar height. The first light-load roller conveyor is connected to the second light-load roller conveyor through the first rotary roller conveyor and has a similar height. The second threshold is greater than the first threshold.

[0009] In one embodiment, the device further includes a double-row high-low roller conveyor and an elevator. The double-row high-low roller conveyor includes a third heavy-load roller conveyor and a third light-load roller conveyor. The third heavy-load roller conveyor is located on one side of the third light-load roller conveyor and is higher than the third light-load roller conveyor. The third light-load roller conveyor is connected to the first light-load roller conveyor and is at a similar height. The third heavy-load roller conveyor is connected to the first heavy-load roller conveyor via the elevator.

[0010] In one embodiment, the distance between the third heavy-load roller conveyor and the third light-load roller conveyor is a third threshold, which is equal to the first threshold.

[0011] In one embodiment, the apparatus further includes a third rotary roller conveyor, the distance between the third heavy-load roller conveyor and the third light-load roller conveyor being a third threshold value, wherein when the third threshold value is not equal to the first threshold value, the third rotary roller conveyor is connected between the first light-load roller conveyor and the third light-load roller conveyor.

[0012] In one embodiment, the apparatus further includes a double-layer roller conveyor and a second rotary roller conveyor. The double-layer roller conveyor includes a fourth heavy-load roller conveyor and a fourth light-load roller conveyor. The fourth light-load roller conveyor is located above the fourth heavy-load roller conveyor and is at a height comparable to that of the third light-load roller conveyor. The fourth heavy-load roller conveyor is connected to the third heavy-load roller conveyor via the second rotary roller conveyor and is at a similar height.

[0013] In one embodiment, the apparatus further includes a fourth rotary roller conveyor connected between the first heavy-duty roller conveyor and the second heavy-duty roller conveyor.

[0014] The aforementioned pallet-type steel coil transport device has a small distance between the first heavy-duty roller and the first light-duty roller of the double-row narrow roller conveyor, making it suitable for foundation pits with small installation spaces. The double-row wide roller conveyor is connected to the double-row narrow roller conveyor through the first rotary roller conveyor. The distance between the second heavy-duty roller conveyor and the second light-duty roller conveyor is greater than the safety distance of the lifting device, so that the lifting device can clamp the steel coil on the second heavy-duty roller conveyor. This device can adapt well to foundation pits with small installation spaces. When the pallet-type steel coil transport device is used to replace the traditional walking beam chain conveyor, the installation of the pallet-type steel coil transport device can be achieved without modifying the foundation pit or with only minor modifications, which is convenient for modification and less time-consuming. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a combination of a double-row narrow roller conveyor and a double-row wide roller conveyor according to an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the structure of a double-row high and low roller conveyor according to an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram of the structure of a double-layer roller conveyor according to an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of a combination of a double-layer roller conveyor and a double-row roller conveyor according to an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of the structure combining a double-row narrow roller conveyor and a double-row wide roller conveyor, according to another embodiment of the present invention.

[0021] Figure label:

[0022] 110. Double-row narrow roller conveyor; 111. First heavy-load roller conveyor; 112. First light-load roller conveyor; 113. First rotary roller conveyor; 120. Double-row wide roller conveyor; 121. Second heavy-load roller conveyor; 122. Second light-load roller conveyor; 123. Fourth rotary roller conveyor; 130. Double-row high-low roller conveyor; 131. Third heavy-load roller conveyor; 132. Third light-load roller conveyor; 133. Third rotary roller conveyor; 140. Double-layer roller conveyor; 141. Fourth heavy-load roller conveyor; 142. Fourth light-load roller conveyor; 143. Second rotary roller conveyor; 210. Elevator; 50. Steel coil; 60. Lifting device. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0028] The following is combined with Figures 1-5 The present invention describes the process and method for modifying the pallet transport system.

[0029] like Figure 1 As shown, in one embodiment, a pallet-type steel coil transport device includes a double-row narrow roller conveyor 110, a first heavy-load roller conveyor 111, a first light-load roller conveyor 112, a double-row wide roller conveyor 120, a second heavy-load roller conveyor 121, a second light-load roller conveyor 122, and a first rotary roller conveyor 113, a steel coil 50, and a lifting device 60.

[0030] The double-row narrow roller conveyor 110 includes a first heavy-load roller conveyor 111 and a first light-load roller conveyor 112. The first heavy-load roller conveyor 111 is located on one side of the first light-load roller conveyor 112 and has a similar height and a spacing of a first threshold.

[0031] The double-row wide roller conveyor 120 includes a second heavy-load roller conveyor 121 and a second light-load roller conveyor 122. The second heavy-load roller conveyor 121 is located on one side of the second light-load roller conveyor 122 and has a similar height and a spacing of a second threshold.

[0032] The first rotary roller conveyor 113 is located at the connection between the double-row narrow roller conveyor 110 and the double-row wide roller conveyor 120;

[0033] The first heavy-load roller conveyor 111 is connected to the second heavy-load roller conveyor 121 and has a similar height. The first light-load roller conveyor 112 is connected to the second light-load roller conveyor 122 through the first rotary roller conveyor 113 and has a similar height. The second threshold is greater than the first threshold.

[0034] A double-row narrow roller conveyor 110 is arranged in front of the coiler. To ensure a safe distance for the lifting device 60 during unloading by the overhead crane, the roller conveyor in the storage area is adjusted from the double-row narrow roller conveyor 110 to a double-row wide roller conveyor 120. Specifically, the first heavy-duty roller conveyor 111 transports pallets containing steel coils 50, and at the turning point, the pallets containing steel coils 50 are transported to the second heavy-duty roller conveyor 121; the first light-duty roller conveyor 112 transports empty pallets, and the empty pallets are transferred to the second light-duty roller conveyor 122 via the first rotary roller conveyor 113. By adjusting the position of the first rotary roller conveyor 113, the second threshold distance between the second heavy-duty roller conveyor 121 and the second light-duty roller conveyor 122 can be adjusted. By adjusting the second threshold, the original double-row narrow roller conveyor 110 is transformed into a double-row wide roller conveyor 120.

[0035] In this embodiment, the pallet-type steel coil transport device has a small distance between the first heavy-duty roller 111 and the first light-duty roller 112 of the double-row narrow roller conveyor 110, which is suitable for foundation pits with small installation space. The double-row wide roller conveyor 120 is connected to the double-row narrow roller conveyor 110 through the first rotary roller conveyor 131. The distance between the second heavy-duty roller conveyor 121 and the second light-duty roller conveyor 122 is greater than the safety distance of the lifting device 60, so that the lifting device 60 can clamp the steel coil 50 on the second heavy-duty roller conveyor 121. This device can adapt well to foundation pits with small installation space. When the pallet-type steel coil transport device is used to replace the traditional walking beam chain conveyor, the installation of the pallet-type steel coil transport device can be achieved without modifying the foundation pit or with only minor modifications, which is convenient for modification and less time-consuming.

[0036] The double-row narrow roller conveyor 110 is widened to a double-row wide roller conveyor 120, which not only meets the need for convenient and quick unloading of the steel coil 50, but also avoids equipment damage caused by collisions during unloading.

[0037] like Figure 2 As shown, in one embodiment, the pallet-type steel coil transport device further includes a double-row high-low roller conveyor 130 and an elevator 210. The double-row high-low roller conveyor 130 includes a third heavy-load roller conveyor 131 and a third light-load roller conveyor 132. The third heavy-load roller conveyor 131 is located on one side of the third light-load roller conveyor 132 and is higher than the third light-load roller conveyor 132. The third light-load roller conveyor 132 is connected to the first light-load roller conveyor 112 and is at a similar height. The third heavy-load roller conveyor 131 is connected to the first heavy-load roller conveyor 111 through the elevator 210.

[0038] The distance between the third heavy-load roller conveyor 131 and the third light-load roller conveyor 132 is a third threshold value, which is equal to the first threshold value. The pallet-type steel coil transport device also includes a third rotary roller conveyor 133. When the third threshold value is not equal to the first threshold value, the third rotary roller conveyor 133 is connected between the first light-load roller conveyor 112 and the third light-load roller conveyor 132.

[0039] When unloading the steel coil 50 from the roller conveyor, to avoid the impact of the narrow roller conveyor spacing on the unloading operation, the double-row narrow roller conveyor 110 is combined with the double-row high-low roller conveyor 130. Specifically, the first heavy-duty roller conveyor 111 of the double-row narrow roller conveyor 110 is connected to the elevator 210. The steel coil 50 transported by the first heavy-duty roller conveyor 111 passes through the elevator 210, and the elevator 210 transports the steel coil 50 upward to the third heavy-duty roller conveyor 131. At this time, the first light-duty roller conveyor 112 is connected to the third light-duty roller conveyor 132 and the heights are equal. The first heavy-duty roller conveyor 111 and the first light-duty roller conveyor 112 are at the same heights, and the third heavy-duty roller conveyor 131 is higher than the third light-duty roller conveyor 132. The double-row narrow roller conveyor 110 is adjusted to the double-row high-low roller conveyor 130. When the first threshold is not equal to the third threshold, the distance between the heavy-load roller conveyor and the light-load roller conveyor is adjusted by the third rotary roller conveyor 133. The third light-load roller conveyor 132 passes through the third rotary roller conveyor 133 during operation. After the third rotary roller conveyor 133 adjusts the position of the third light-load roller conveyor 132, it is connected to the first light-load roller conveyor 112.

[0040] In this embodiment, the pallet-type steel coil transport device connects the double-row narrow roller conveyor 110 with the double-row high and low roller conveyor 130. When the crane unloads the steel coil 50, the heavy-load roller conveyor is higher than the light-load roller conveyor, making it easier to unload the steel coil 50 on the pallet, thus improving production efficiency and reducing the risk of unloading.

[0041] like Figure 3 Figure 4 As shown, in one embodiment, the pallet-type steel coil transport device further includes a double-layer roller conveyor 140 and a second rotary roller conveyor 143. The double-layer roller conveyor 140 includes a fourth heavy-load roller conveyor 141 and a fourth light-load roller conveyor 142. The fourth light-load roller conveyor 142 is located above the fourth heavy-load roller conveyor 141 and its height is approximately the same as that of the third light-load roller conveyor 132. The fourth heavy-load roller conveyor 141 is connected to the third heavy-load roller conveyor 132 through the second rotary roller conveyor 143 and their heights are approximately the same.

[0042] The double-layer roller conveyor 140 is combined with the double-row high-low roller conveyor 130. Specifically, the fourth heavy-load roller conveyor 141 and the fourth light-load roller conveyor 142 of the double-layer roller conveyor 140 operate in two layers, one above the other. The fourth heavy-load roller conveyor 141 is located below the fourth light-load roller conveyor 142. Empty pallets on the fourth light-load roller conveyor 142 are transported to the fourth heavy-load roller conveyor 141 via the elevator 210. After the steel coil 50 is placed on the empty pallet, it is transported by the fourth heavy-load roller conveyor 141. When the fourth heavy-load roller conveyor 141 moves forward, it passes the second rotary roller conveyor 143. The second rotary roller conveyor 143 rotates the fourth heavy-load roller conveyor 141 to the side, and the distance between it and the light-load roller conveyor is the second threshold. The fourth light-load roller conveyor 142 runs along its original path. The elevation of the fourth heavy-load roller conveyor 141 is lower than that of the fourth light-load roller conveyor 142. At this time, the double-layer roller conveyor 140 is adjusted to a double-row high-low roller conveyor 130. At this time, because the fourth heavy-load roller conveyor 141 is lower than the fourth light-load roller conveyor 142, it will be extremely inconvenient to unload the steel coil 50. Therefore, a lift 210 is installed in the running path of the fourth light-load roller conveyor 142, and the fourth light-load roller conveyor 142 is lowered to the same height as the fourth heavy-load roller conveyor 141. The double-layer roller conveyor 140 is adjusted to a double-row wide roller conveyor 120.

[0043] In this embodiment, the pallet-type steel coil transport device first adjusts the double-layer roller conveyor 140 into a double-row high and low roller conveyor 130, and then adjusts it into a double-row wide roller conveyor 120 connected by a lift 210. This solves the problem of the deep foundation pit required for the double-layer roller conveyor 140, greatly reduces the amount of civil engineering construction, and meets the short-term and high-efficiency nature of annual maintenance projects.

[0044] like Figure 5 As shown, in one embodiment, the pallet-type steel coil transport device further includes a fourth rotary roller conveyor 123, which is connected between the first heavy-duty roller conveyor 111 and the second heavy-duty roller conveyor 121.

[0045] If the first heavy-duty roller conveyor 111 and the second heavy-duty roller conveyor 121 run in a straight line, then the fourth rotary roller conveyor 123 is not needed; if the first heavy-duty roller conveyor 111 and the second heavy-duty roller conveyor 121 do not run in a straight line, then the fourth rotary roller conveyor 123 is needed to connect them. Specifically, when the first heavy-duty roller conveyor 111 reaches the fourth rotary roller conveyor 123, the fourth rotary roller conveyor 123 changes the running direction of the roller conveyor and connects with the second heavy-duty roller conveyor 121.

[0046] The pallet-type steel coil transport device of this embodiment uses a fourth rotary roller conveyor 123 to connect the first heavy-duty roller conveyor 111 and the second heavy-duty roller conveyor 121, which increases the multi-scenario use of the double-row narrow roller conveyor 110 and the double-row wide roller conveyor 120, and meets the needs of arranging roller conveyors in complex situations in tunnels.

[0047] The installation method of the above-mentioned pallet-type steel coil transport device is described as follows:

[0048] Determine the size of the foundation pit in front of the coiler.

[0049] The arrangement of the roller conveyor in front of the coiler is determined based on the size of the foundation pit in front of the coiler.

[0050] The arrangement of roller conveyors within the storage area is determined based on the type of roller conveyor in front of the coiler.

[0051] Based on the size of the foundation pit in front of the coiler, the arrangement of the roller conveyor in front of the coiler is determined, including:

[0052] The foundation pit is wide enough to accommodate double rows of wide roller conveyors.

[0053] The foundation pit is too narrow, so double-row narrow roller conveyors should be installed.

[0054] The foundation pit is deep enough to accommodate a double-layer roller conveyor.

[0055] The foundation pit is too narrow and the foundation pit is not deep enough, so a single row of roller conveyors should be installed.

[0056] The arrangement of roller conveyors within the storage area is determined based on the type of roller conveyor in front of the coiler, including:

[0057] The foundation pit is equipped with double-row wide roller conveyors, and the warehouse area is also equipped with double-row wide roller conveyors.

[0058] The foundation pit is equipped with double-row narrow roller conveyors, and the warehouse area is equipped with double-row high and low roller conveyors.

[0059] The foundation pit is equipped with double-row narrow roller conveyors, and the warehouse area is equipped with double-row wide roller conveyors.

[0060] The foundation pit is equipped with a double-layer roller conveyor, and the warehouse area is equipped with a double-row high and low roller conveyor.

[0061] The foundation pit is equipped with a double-layer roller conveyor, and the warehouse area is equipped with a double-row wide roller conveyor.

[0062] The foundation pit is equipped with a single row of roller conveyors, while the warehouse area is equipped with a double row of wide roller conveyors.

[0063] Specifically, the foundation pit in front of the coiler is analyzed based on the project site conditions, and different solutions are formulated according to the size of the foundation pit. If the foundation pit width is sufficient, a double-row wide roller conveyor is directly installed; if the foundation pit width is too narrow, a double-row narrow roller conveyor is installed; if the foundation pit depth is sufficient but the width does not meet the requirements for a double-row narrow roller conveyor, a double-layer roller conveyor is installed; if the foundation pit width is too narrow to meet the requirements for a double-row narrow roller conveyor and the depth does not meet the requirements for a double-layer roller conveyor, a single-row roller conveyor is installed.

[0064] If the roller conveyor in front of the coiler is a double-row wide roller conveyor, the roller conveyor layout in the storage area can also be directly arranged as a double-row wide roller conveyor. If the roller conveyor in front of the coiler is a double-row narrow roller conveyor, in order not to affect the unloading of steel coils, it can be adjusted to a double-row high-low roller conveyor using an elevator, or it can be converted into a double-row wide roller conveyor using a rotary roller conveyor. If the roller conveyor in front of the coiler is a double-layer spacing, the required pit depth will increase the amount of civil construction. It can be converted into a double-row high-low roller conveyor using a rotary roller conveyor in the storage area, or an elevator can be used to further convert the converted double-row high-low roller conveyor into a double-row wide roller conveyor. If the roller conveyor in front of the coiler is a single-row roller conveyor, it needs to be converted into a double-row wide roller conveyor at a suitable location using a rotary roller conveyor.

[0065] The pallet transport system modification method in this embodiment determines the space in the tunnel in front of the coiler by investigating different site conditions. The layout of the new pallet transport system in the foundation pit is determined by the space in the tunnel in front of the coiler. The roller conveyor in the warehouse area is then arranged based on the layout of the new pallet transport system in the foundation pit. Various on-site difficulties can be solved by combining multiple process types, reducing the amount of civil engineering foundation construction during the annual maintenance period, and saving more time for equipment installation and commissioning. It is suitable for the efficient and time-saving nature of annual maintenance and renovation projects.

[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A pallet-type steel coil transport device, characterized in that, The device includes: The lifting device, with double-row narrow roller conveyors arranged in front of the coiler, has a distance between the second heavy-duty roller conveyor and the second light-duty roller conveyor that is greater than the safe distance of the lifting device. The double-row narrow roller conveyor includes a first heavy-load roller conveyor and a first light-load roller conveyor. The first heavy-load roller conveyor is located on one side of the first light-load roller conveyor and has a similar height and a spacing of a first threshold. The double-row wide roller conveyor includes a second heavy-load roller conveyor and a second light-load roller conveyor. The second heavy-load roller conveyor is located on one side of the second light-load roller conveyor and has a similar height and a spacing of a second threshold. The first rotary roller conveyor is located at the connection between the double-row narrow roller conveyor and the double-row wide roller conveyor; Wherein, the first heavy-load roller conveyor is connected to the second heavy-load roller conveyor and has a similar height, the first light-load roller conveyor is connected to the second light-load roller conveyor through the first rotary roller conveyor and has a similar height, and the second threshold is greater than the first threshold. The device also includes a double-row high and low roller conveyor and an elevator. The double-row high and low roller conveyor includes a third heavy-load roller conveyor and a third light-load roller conveyor. The third heavy-load roller conveyor is located on one side of the third light-load roller conveyor and is higher than the third light-load roller conveyor. The third light-load roller conveyor is connected to the first light-load roller conveyor and is at the same height. The third heavy-load roller conveyor is connected to the first heavy-load roller conveyor through the elevator. The device further includes a double-layer roller conveyor and a second rotary roller conveyor. The double-layer roller conveyor includes a fourth heavy-load roller conveyor and a fourth light-load roller conveyor. The fourth light-load roller conveyor is located above the fourth heavy-load roller conveyor and its height is approximately the same as that of the third light-load roller conveyor. The fourth heavy-load roller conveyor is connected to the third heavy-load roller conveyor through the second rotary roller conveyor and their heights are approximately the same.

2. The pallet-type steel coil transport device according to claim 1, characterized in that, The distance between the third heavy-load roller conveyor and the third light-load roller conveyor is a third threshold value, which is equal to the first threshold value.

3. The pallet-type steel coil transport device according to claim 1, characterized in that, The device further includes a third rotary roller conveyor, the distance between the third heavy-load roller conveyor and the third light-load roller conveyor is a third threshold value, and when the third threshold value is not equal to the first threshold value, the third rotary roller conveyor is connected between the first light-load roller conveyor and the third light-load roller conveyor.

4. The pallet-type steel coil transport device according to claim 1, characterized in that, The device further includes a fourth rotary roller conveyor connected between the first heavy-duty roller conveyor and the second heavy-duty roller conveyor.

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