Tensioning device for metal mesh belts

Abstract

The present invention provides a tensioning device for a metal mesh belt that can maintain the appropriate tension on the metal mesh belt and easily and accurately equalize the tension in the width direction of the belt. [Solution] The tension-applying device 10 comprises a pair of moving mechanisms 20 that hold the driven roller 4 so that it can move closer to and away from the drive roller 3, and a pair of biasing force generating mechanisms 30 that bias the driven roller 4 in a direction away from the drive roller 3. The moving mechanism 20 consists of bearings 21 provided at both ends of the driven roller 4, and an upper sliding member 23 and a lower sliding member 24 that hold the bearings 21. The biasing force generating mechanism 30 consists of an air spring 31, a fixing member 32 that fixes the air spring 31 to the frame 2, and a connecting member 35 that connects the air spring 31 and the bearing 21. The pressure of the compressed air stored inside the air springs 31 of the pair of biasing force generating mechanisms 30 is made equal, thereby equalizing the tension applied to the metal mesh belt 5 in the width direction.

Description

Technical Field

[0001] The present invention relates to a tension applying device for a metal mesh belt in a belt conveyor that loads and continuously conveys loose materials such as raw materials ( conveyed materials) on an endless metal mesh belt.

Background Art

[0002] A belt conveyor that loads and continuously conveys loose materials such as raw materials ( conveyed materials) has a belt wound around a driving roller and a driven roller, and the conveyed material is loaded on this belt and conveyed from the driven roller side toward the driving roller side.

[0003] For example, in a belt conveyor used in a food steamer or cooler, when the conveyed material becomes hot or when it is necessary to ventilate and cool the conveyed material, a metal mesh belt formed with a mesh using a stainless steel wire or a steel belt formed with through holes in a metal belt is selected. The metal mesh belt can configure the device more compactly than the steel belt and is widely used because it is inexpensive. Therefore, we decided to study a device for applying tension specialized for a metal mesh belt.

[0004] When the temperature of the metal mesh belt changes during operation, such as in a steamer or cooler, thermal expansion and contraction of the belt occur and the tension of the belt fluctuates. When the tension of the belt weakens, the frictional force between the belt and the driving roller decreases, causing the belt to slip and unable to convey the conveyed material. Also, if the degree of thermal expansion and contraction is different in the width direction of the belt, a difference in tension occurs in the width direction of the belt, causing the belt to meander. Furthermore, when the difference in tension in the width direction of the belt becomes large, the mesh structure of the metal mesh belt may be permanently deformed partially. Therefore, in a metal mesh belt, it is necessary to maintain an appropriate belt tension and equalize the tension in the width direction of the belt.

[0005] Regarding the application of tension to a metal mesh belt, Patent Document 1 discloses that a driven roller 52 is movable in the axial direction by a tensioner 55, and that a predetermined tension is applied to the conveyor 4 by moving the driven roller 52 (paragraph

[0021] ). According to Figure 1 of the same, the tensioner 55 is presumed to be an air cylinder or a hydraulic cylinder.

[0006] Patent Document 2 discloses that the outer surface of the belt 1 is pressurized in a direction approximately normal to the belt by a tension roller 6, and the tension of the belt 1 is maintained by the tension roller 6 (paragraph

[0011] , Figures 6, 7). In other words, the tension roller 6 applies force along the direction approximately normal to the belt while maintaining a constant distance between the drive roller and the driven roller, thereby applying tension to the belt. Although the type of belt is not described, a mechanism similar to the tension adjustment device described in Patent Document 2 has conventionally been used in metal mesh belts. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2002-199986 [Patent Document 2] Japanese Patent Application Publication No. 10-273212 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, using an air cylinder or hydraulic cylinder, as in the tensioning device for a metal mesh belt described in Patent Document 1, requires high precision in the manufactured parts because the direction and surface of the cylinder's pressure are strictly defined, which increases costs. Furthermore, if assembly errors occur and the cylinder is pressed while slightly tilted, there is a risk that the intended biasing force cannot be applied.

[0009] Furthermore, if the cylinder remains slightly tilted and pressed continuously, lateral loads, i.e., loads in a direction intersecting the expansion and contraction direction, will cause uneven wear of the piston packing and rod packing, eventually leading to air or oil leakage. If the biasing force applied to one of the pair of cylinders mounted on the axis of the driven roller decreases, a difference in biasing force will occur in the width direction, causing the belt to meander, and if the difference in biasing force becomes even larger, the mesh structure of the belt may deform.

[0010] In the tensioning device described in Patent Document 2, in light of the relatively frequent occurrence of the belt 118 breaking due to a decrease in the rigidity of the belt 118 caused by temperature changes, a system that is easy to replace is disclosed (paragraphs

[0006] ,

[0008] ). However, in a configuration in which the belt 1 is bent inward by two tension rollers 6 to maintain tension (paragraph

[0011] As shown in Figures 6 and 7, compared to a configuration without tension rollers, the belt 1 is more prone to bending and friction, which is likely to shorten its lifespan. In addition, the device configuration becomes more complex, and it is expected that adjusting the tension will take more time.

[0011] The present invention solves the conventional problems of increased costs due to the use of cylinders as described above, and of meandering and deformation of the mesh structure caused by differences in tension in the width direction on the metal mesh belt, thereby extending the life of the belt. In other words, the present invention aims to provide a tensioning device for a metal mesh belt that can accurately and easily equalize the tension on the metal mesh belt in the width direction while responding to tension fluctuations due to thermal expansion and contraction of the metal mesh belt, and does not place an excessive load on the metal mesh belt. [Means for solving the problem]

[0012] The tensioning device for a metal mesh belt of the present invention is provided on a belt conveyor having a frame, a drive roller and a driven roller provided on the frame, and a metal mesh belt wrapped around the drive roller and the driven roller, wherein the tensioning device for a metal mesh belt is provided on a belt conveyor having a frame, a drive roller and a driven roller provided on the frame, and a pair of biasing force generating mechanisms that bias the driven roller in a direction away from the drive roller, wherein the movement mechanism is composed of bearings provided at both ends of the driven roller and an upper slide member and a lower slide member fixed to the frame that hold the bearings, wherein the biasing force generating mechanism is composed of an air spring, a fixing member that fixes the air spring to the frame, and a connecting member that connects the air spring and the bearing, wherein the pressure of the compressed air stored inside the air springs of the pair of biasing force generating mechanisms is made the same, thereby equalizing the tension applied to the metal mesh belt in the width direction. [Effects of the Invention]

[0013] The tensioning device for a metal mesh belt of the present invention reduces costs by employing a pair of moving mechanisms and a pair of biasing force generating mechanisms. Furthermore, by simply adjusting the pressure of the compressed air stored inside the air springs of the pair of biasing force generating mechanisms to be the same, the tension applied to the metal mesh belt can be accurately and easily equalized in the width direction while responding to tension fluctuations due to thermal expansion and contraction of the metal mesh belt, thereby preventing meandering and deformation of the mesh structure. In addition, since excessive load is not placed on the metal mesh belt, the lifespan of the metal mesh belt is extended. [Brief explanation of the drawing]

[0014] [Figure 1] Side view of a belt conveyor used in a cooling machine equipped with a tension-applying device according to one embodiment of the present invention. [Figure 2] Cross-sectional view along line II-II in Figure 1 [Figure 3]A side view of one of the pair of tension-applying devices shown in Figure 2. [Figure 4] Enlarged side view showing the main parts of the tension-applying device shown in Figure 3. [Figure 5] Cross-sectional view along line VV in Figure 4. [Modes for carrying out the invention]

[0015] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The present invention relates to a tensioning device for a metal mesh belt installed on a belt conveyor. The belt conveyor can be any belt having a metal mesh belt. For example, a belt conveyor used in a steamer or cooler for food products can be used, and more specifically, a belt conveyor used in a rice steamer or cooler can be used. First, an overview of a belt conveyor equipped with the metal mesh belt tensioning device of the present invention will be described with reference to Figures 1 and 2. Figure 1 shows a side view of a belt conveyor 1 used in a cooler equipped with a tensioning device 10 according to one embodiment of the present invention. Note that only the main parts of the belt conveyor 1 are shown in Figure 1, and the external case and structural components such as the drive motor are not shown.

[0016] As shown in Figure 1, the main part of the belt conveyor 1 is formed by a frame 2, a drive roller 3 and a driven roller 4 provided on the frame 2, and an endless metal mesh belt 5 wrapped around the drive roller 3 and the driven roller 4.

[0017] The drive roller 3 is a roller fixed in position to the frame 2 and rotatably mounted, and is driven by a drive motor (not shown). The driven roller 4 is mounted so that its central axis is parallel to the central axis of the drive roller 3 and rotatably mounted. When the drive roller 3 is driven, the metal mesh belt 5 circulates between the upper and lower sides (arrows A and B). In the belt conveyor 1 used in the cooling machine, the conveyed material (e.g., steamed rice) loaded on the metal mesh belt 5 is cooled by supplied air as it is conveyed downstream (in the direction of arrow A).

[0018] The shapes of the drive roller 3 and the driven roller 4 may be those generally used for a belt conveyor. For the drive roller 3, a roller with a lining process or groove process in which the roller surface is covered with rubber to prevent slippage of the metal mesh belt 5 may be used. The driven roller 4 may be a cylindrical roller or a roller having a shape in which the diameters of both ends are slightly shorter.

[0019] Hereinafter, the structure of the tension applying device 10 according to an embodiment of the present invention will be described with reference to FIGS. 2 to 5. FIG. 2 is a cross-sectional view taken along the line II-II of the belt conveyor 1 shown in FIG. 1. FIG. 3 is a side view of one of the pair of tension applying devices 10 shown in FIG. 2. FIG. 4 is an enlarged side view showing the main part of the tension applying device 10 shown in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4. In FIGS. 4 and 5, a part of the frame 2 is omitted, and in FIG. 5, the metal mesh belt 5 is omitted. In the following description, the conveying direction of the metal mesh belt 5 will be described as the front-rear direction, the drive roller 3 side as the front (right side in FIG. 1) when viewed from the driven roller 4, and the driven roller 4 side as the rear (left side in FIG. 1) when viewed from the drive roller 3.

[0020] As shown in FIG. 2, the tension applying device 10 of the present embodiment includes a pair of moving mechanisms 20 that hold the driven roller 4 so as to be able to approach and separate from the drive roller 3 whose position is fixed to the frame 2, and a pair of biasing force generating mechanisms 30 that bias the driven roller 4 in a direction away from the drive roller 3. The pair of moving mechanisms 20 and the pair of biasing force generating mechanisms 30 are provided at both ends of the driven roller 4, respectively. For the sake of convenience, the configuration of the moving mechanism 20 and the biasing force generating mechanism 30 on the right side of the driven roller 4 in FIG. 2 will be described as a representative.

[0021] As shown in FIG. 3, the moving mechanism 20 is composed of a bearing 21 provided at the end of the driven roller 4, an upper slide member 23 and a lower slide member 24 fixed to the frame 2 that holds the bearing 21. The biasing force generating mechanism 30 is composed of an air spring 31, a fixing member 32 that fixes the air spring 31 to the frame 2, and a connecting member 35 that connects the air spring 31 and the bearing 21.

[0022] As shown in FIGS. 4 and 5, the bearing 21 of the moving mechanism 20 rotatably holds the shaft end of the driven roller 4, and concave grooves are formed as upper rail receivers 21a and lower rail receivers 21b at the upper and lower ends of the bearing 21. The upper slide member 23 and the lower slide member 24 are respectively fitted into the concave grooves of the upper rail receiver 21a and the lower rail receiver 21b of the bearing 21, and hold the bearing 21 in a state where it can move in the front - rear direction. The cross - sectional shapes of the upper slide member 23 and the lower slide member 24 and the cross - sectional shapes of the upper rail receiver 21a and the lower rail receiver 21b of the bearing 21 may be angular or arc - shaped as long as the slide member and the rail receiver are in a shape where they can slide - contact and move, and the slide member can be inserted into the rail receiver.

[0023] Also, a take - up type bearing that can move the driven roller 4 smoothly and stably is adopted for the bearing 21 of the present embodiment. The bearing is not limited to the take - up type bearing, and any bearing that can move smoothly and stably in the front - rear direction while being held by the upper slide member and the lower slide member is acceptable. For example, guide grooves or the like may be provided along the front - rear direction on the lower surface of the upper slide member and the upper surface of the lower slide member, and the upper and lower ends of the bearing may be accommodated in these grooves so that the bearing can move in the front - rear direction.

[0024] Next, as shown in Figures 4 and 5, the air spring 31 of the biasing force generating mechanism 30 is equipped with a rubber bellows 311 that stores compressed air inside, and an intermediate ring 312 is provided in the valley portion of the rubber bellows 311 to suppress expansion in the outer peripheral direction. A front end member 313 and a rear end member 314 are provided at both ends of the rubber bellows 311 in the direction of expansion and contraction. The fixing member 32 is fixed to the frame 2 so that its rear surface is perpendicular to the front-rear direction of the belt conveyor 1, and the front end member 313 of the air spring 31 is attached to this rear surface. In other words, the air spring 31 is provided so that its expansion and contraction direction is in the front-rear direction and the base point of its expansion and contraction is the rear surface of the fixing member 32. In this embodiment, the fixing member 32 and the front end member 313 are fixed by bolts, but this is not particularly limited.

[0025] The air spring 31 is connected to the bearing 21 via a connecting member 35. The connecting member 35 is a two-stage stepped shaft with a circular cross-section, fixed to the rear end member 314 such that its central axis is coaxial with the central axis of the air spring 31. Specifically, the connecting member 35 is formed from an insertion portion 35a that is inserted into the insertion hole 21c of the bearing 21, a contact portion 35b that abuts against the bearing 21, and a base end portion 35c that is fixed to the air spring 31. The shaft diameter of the insertion portion 35a is formed to be approximately the same as the inner diameter of the insertion hole 21c, making it less likely to shift radially when connected. In addition, the shaft diameter of the contact portion 35b is larger than the shaft diameter of the insertion portion 35a, so that the rear surface of the contact portion 35b abuts against the front end surface of the bearing 21 when connected. Furthermore, the shaft diameter of the base portion 35c is larger than the shaft diameter of the contact portion 35b, and it is bolted to the rear end member 314 of the air spring 31. Therefore, the bearing 21 can be moved stably along the expansion and contraction direction of the air spring 31. The method of connecting the bearing 21 and the connecting member 35 is not particularly limited, as long as the insertion portion 35a of the connecting member 35 can be inserted into and removed from the insertion hole 21c.

[0026] By providing a pair of moving mechanisms 20 and a pair of biasing force generating mechanisms 30 having the above configuration, the tension on the metal mesh belt 5 can be accurately and easily equalized in the width direction while responding to tension fluctuations due to thermal expansion and contraction of the metal mesh belt 5, simply by adjusting the pressure of the compressed air stored inside the air springs 31 of the pair of biasing force generating mechanisms 30 to be the same, thereby preventing meandering and deformation of the mesh structure. Furthermore, since excessive load is not placed on the metal mesh belt 5, the lifespan of the metal mesh belt 5 is extended.

[0027] The air spring 31 described above has an effective diameter defined as the diameter at which pressure is effectively applied when the rubber bellows 311 is held at a standard height and a constant amount of compressed air is stored. The effective diameter of the air spring 31 of the biasing force generating mechanism 30 is preferably 100 to 350 mm, and more preferably 120 to 330 mm. In addition, the amount of movement of the bearing 21 in the front-rear direction by the moving mechanism 20 is preferably 1 to 50 mm, and more preferably 1 to 30 mm. With this effective diameter and amount of movement, the expansion and contraction of the air spring 31 is performed appropriately, and even if tension fluctuations occur due to thermal expansion and contraction of the metal mesh belt 5 or if there is a misalignment between the air spring 31 and the bearing 21, the driven roller 4 can be moved stably and appropriate tension can be applied to the metal mesh belt 5.

[0028] The amount of movement of the bearing 21 in the front-rear direction by the moving mechanism 20 may be limited by using an air spring 31 whose maximum extension stroke is within the above range. Alternatively, as shown in Figures 3 and 4, a stopper 40 may be provided on the frame 2 that contacts the bearing 21 when it moves backward to limit its movement. In this configuration, the maximum amount of movement of the bearing 21 can be easily adjusted by adjusting the amount of protrusion of the stopper 40 that protrudes toward the bearing 21.

[0029] One embodiment of the present invention has been described, but the present invention is not limited thereto and may be modified in any way as appropriate. For example, the air spring 31 may have a flat, membrane-like diaphragm without bellows instead of a rubber bellows 311. Any member that stores compressed air can be used as an air spring if it is expandable and contractible along the axial direction and has a structure that does not easily bend or deform when expanding and contracting in the axial direction. Furthermore, if the air spring 31 has a rubber bellows 311, the number of peaks in the rubber bellows 311 and the number of intermediate rings 312 provided in the valleys are not particularly limited, and the intermediate rings 312 do not necessarily have to be provided. [Examples]

[0030] The present embodiment will be described in more detail below, with reference to examples of the present invention. In this embodiment, the effectiveness of the tensioning device 10 for the metal mesh belt 5 of the present invention was confirmed by using the belt conveyor 1 of the cooling machine shown in Figures 1 to 5 to cool the steamed rice immediately after steaming.

[0031] The specifications for belt conveyor 1 are as follows: Metal mesh belt 5 (stainless steel wire): Net width 1800mm Driven roller 3 and driven roller 4: Width 1850 mm, Diameter 400 mm Distance L between the axes of the drive roller 3 and the driven roller 4: 8000 mm

[0032] The specifications of the air spring 31 of the tensioning device 10 for the metal mesh belt 5 are as follows: Effective diameter: 220mm Number of peaks on rubber bellows 311: 2 Movement (extension / contraction) of bearing 21: 15 mm Pressure of compressed air stored in air spring 31: 0.15 MPa

[0033] Furthermore, when the temperature of the metal mesh belt 5 was measured, it was 25°C before operation, and the temperatures at the inlet and outlet sides during operation were 90°C and 32°C, respectively. One hour after the end of operation, the temperature was 27°C.

[0034] As a result of the operation, no deflection or loosening (tension reduction) occurred due to thermal expansion and contraction of the metal mesh belt 5 caused by temperature changes during operation, and no slippage occurred due to a decrease in frictional force between the metal mesh belt 5 and the drive roller 3. In addition, since the biasing force applied to both ends of the driven roller 4 was maintained at the same level, no meandering of the metal mesh belt 5 occurred. Furthermore, after the operation ended, the compressed air stored in the air spring 31 was released to remove the tension applied to the metal mesh belt 5, and the condition of the metal mesh belt 5 was checked, and there was no deformation of the mesh structure compared to before operation. As described above, no problems such as poor conveyance of steamed rice occurred during the operation of the cooling machine. From this, it can be inferred that the tension-applying device 10 for the metal mesh belt 5 of the present invention was able to equalize the tension applied to the metal mesh belt 5 in the width direction at all times during operation.

[0035] Therefore, by employing the tension-applying device 10 for the metal mesh belt 5 of the present invention, the tension applied to the metal mesh belt 5 can be accurately and easily equalized in the width direction while responding to tension fluctuations due to thermal expansion and contraction of the metal mesh belt 5, thereby preventing meandering and deformation of the mesh structure. Furthermore, since excessive load is not placed on the metal mesh belt 5, the lifespan of the metal mesh belt 5 is extended. [Explanation of Symbols]

[0036] 1. Belt conveyor 2 frames 3 Drive rollers 4 Driven rollers 5. Metal mesh belt 10. Tension-applying device 20 Moving mechanism 21 Bearings 21a Upper rail support 21b Lower rail support 21c Insertion hole 23 Upper sliding member 24 Lower sliding member 30. Mechanism for generating biasing force 31 Air spring 311 Rubber bellows 312 Intermediate ring 313 Front end member 314 Rear end member 32 Fixing member 35 Connecting member 35a Insertion part 35b Contact part 35c proximal end 40 Stopper A Arrow B Arrow L distance

Claims

[Claim 1] Frame and, The frame includes a drive roller and a driven roller, A belt conveyor having a metal mesh belt wrapped around the drive roller and the driven roller is provided, A tensioning device for a metal mesh belt, The tensioning device for the aforementioned metal mesh belt is A pair of moving mechanisms that hold the driven roller so that it can move toward and away from the drive roller, which is fixed in position on the frame, The system includes a pair of biasing force generating mechanisms that bias the driven roller in a direction away from the drive roller, The aforementioned moving mechanism is Bearings provided at both ends of the driven roller, It consists of an upper sliding member and a lower sliding member fixed to the frame that holds the bearing, The aforementioned biasing force generation mechanism is Air springs and, A fixing member for fixing the air spring to the frame, It consists of a connecting member that connects the air spring and the bearing, A tensioning device for a metal mesh belt, characterized by equalizing the pressure of compressed air stored inside the air springs of a pair of biasing force generating mechanisms, thereby equalizing the tension applied to the metal mesh belt in the width direction.

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