Conveying device

Abstract

The present invention provides a conveying device that allows for smooth movement of the conveyor belt even when the radius is reduced in curved sections. [Solution] A conveying device in which multiple conveyor belts 3 run parallel in a curved section, comprising a first winding section 6 around which each conveyor belt 3 is wrapped to form a first folded section 4 of the conveyor belt 3, and a second winding section around which each conveyor belt 3 is wrapped to form a second folded section of the conveyor belt 3, wherein each conveyor belt 3 has a conveying section 8 above the first folded section 4 and a return section 9 below, the portion adjacent to the first folded section 4 in the conveying section 8 is a first upper transition section 11, and the portion adjacent to the first folded section 4 in the return section 9 is a first lower transition section 13, and the first upper transition section 11 and the first lower transition section 13 are composed of a straight section 15.

Description

Technical Field

[0001] The present invention relates to a conveying device in which a plurality of conveyor belts run side by side in a curved portion.

Background Art

[0002] Among the conveying devices using endless conveyor belts, there are some having a curved portion in the conveying path (see Patent Document 1 and Patent Document 2). In the conveying device in Patent Document 1, a plurality of conveyor belts run side by side in the curved portion. Each conveyor belt is configured with a folded-back portion at both ends. Each conveyor belt meshes with a sprocket at one folded-back portion and runs by the rotation of the sprocket.

[0003] The upper side of each conveyor belt serves as a conveying portion for conveying a workpiece. Also, the lower side serves as a return portion. And in the conveying portion, the conveyor belt runs from one first folded-back portion toward the other second folded-back portion. In the return portion, it runs from the second folded-back portion toward the first folded-back portion. In the curved portion of the conveyor belt, the radius of the conveying portion and the radius of the return portion are configured to be the same. Among the conveyor belts running side by side, the conveyor belt on the inner peripheral side has a smaller radius than the conveyor belt on the outer peripheral side. That is, the curve becomes steeper. For this reason, the plurality of conveyor belts running side by side run at a faster speed on the outer peripheral side than on the inner peripheral side.

[0004] Also, in the conveying device in Patent Document 2, at both ends of the curved portion, the radius on the inner peripheral side is smaller than that on the outer peripheral side, that is, the curve becomes steeper. Therefore, a conical roller is used in the folded-back portion of the conveyor belt. The conical roller is configured such that the diameter of the inner peripheral side is larger than that of the outer peripheral side. Thereby, the contact angle between the conical roller and the conveyor belt is made equal on the inner and outer peripheries.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] International Publication No. 2022 / 211628 [Patent Document 2] International Publication No. 2019 / 177455 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the conveying device described in Patent Document 1, the conveyor belt enters the turnaround section directly from the curved section. As a result, the curve is sharper on the inner circumference of the conveyor belt than on the outer circumference, causing the angle of entry into the turnaround section to be acute. Consequently, the conveyor belt may get caught on the frame or other components. This catching of the conveyor belt on the frame or other components may cause damage to the conveyor belt.

[0007] Furthermore, Patent Document 2 states that conical rollers must be provided according to the radius of the curved section. Also, the conveyor belt will twist as it is guided by the conical rollers. As a result, fatigue will accumulate in the conveyor belt over time, which may lead to breakage. [Means for solving the problem]

[0008] A conveying device for solving the above problems is a conveying device in which a plurality of conveyor belts run parallel in a curved section, comprising a first winding section in which each conveyor belt is wound to form a first return section, and a second winding section in which each conveyor belt is wound to form a second return section, wherein each conveyor belt has a conveying section above the first winding section and a return section below the first winding section and the second winding section, the portion of the conveying section adjacent to the first winding section is a first upper transition section, the portion of the conveying section adjacent to the second winding section is a second upper transition section, the portion of the return section adjacent to the first winding section is a first lower transition section, and the portion of the return section adjacent to the second winding section is a second lower transition section, and at least one of the first upper transition section, the second upper transition section, the first lower transition section, and the second lower transition section has a straight section.

[0009] According to the above configuration, the conveyor belt stabilizes in the straight section before entering the winding or curved section. As a result, the conveyor belt can travel smoothly. Furthermore, even if the radius of the curve is made smaller and sharper, the conveyor belt can still travel smoothly. For example, it is possible to prevent the components of the conveyor belt from getting caught on adjacent parts such as frames. In addition, the conveyor belt can be engaged with the drive sprocket without causing tooth skipping.

[0010] In the above-described conveying device, the first winding section is on the drive side and includes a drive sprocket between the first upper transition section and the first lower transition section that engages each conveyor belt, the second winding section is on the driven side and includes an idler between the second upper transition section and the second lower transition section around which each conveyor belt is wound, each conveyor belt travels in the direction from the first winding section to the second winding section in the return section and in the direction from the second winding section to the first winding section in the conveying section, and the straight section is preferably provided at least in the first upper transition section.

[0011] According to the above configuration, the straight section provided in the first upper transition section can stabilize the posture of the conveyor belt just before it enters the first winding section from the curved section of the conveying section. This allows, for example, the conveyor belt to be reliably engaged with the drive sprocket.

[0012] In the above-described conveying device, it is preferable that the straight section is also provided in the first lower transition section. With this configuration, the straight section can stabilize the posture of the conveyor belt sent out from the first winding section before sending it to the curved section of the return section. This makes it possible to smooth the movement of the conveyor belt.

[0013] In the above-described conveying device, it is preferable that the straight section is also provided in the second lower transition section. With this configuration, the straight section provided in the second lower transition section can stabilize the posture of the conveyor belt just before it enters the second winding section from the curved portion of the return section. As a result, the straight section can reliably engage the conveyor belt with the idler, for example.

[0014] In the above-described conveying device, it is preferable that the straight section is also provided in the second upper transition section. With this configuration, the straight section provided in the second upper transition section can stabilize the posture of the conveyor belt sent out from the second winding section before sending it to the curved section of the conveying section. This makes it possible to smooth the movement of the conveyor belt.

[0015] In the above-described conveying device, the first winding section comprises a first upper guide section provided adjacent to the first upper transition section and a first lower guide section provided adjacent to the first lower transition section, the second winding section comprises a second upper guide section provided adjacent to the second upper transition section and a second lower guide section provided adjacent to the second lower transition section, the first lower guide section is offset toward the curved section side from the first upper guide section, the second lower guide section is offset toward the curved section side from the second upper guide section, and it is preferable that the straight section is provided in at least one of the first lower transition section and the second lower transition section.

[0016] With the above configuration, since the first lower guide section and the second lower guide section are offset towards the curved section, the length of the conveyor belt's travel path on the return section side becomes shorter than the length of the conveyor belt's travel path on the transport section side. In other words, the length of the travel path in the curved section between the first lower guide section and the second lower guide section in the return section becomes shorter than the length of the travel path in the curved section between the first upper guide section and the second upper guide section in the transport section. As a result, the radius of the curved section on the return section side becomes smaller than the radius of the curved section on the transport section side, resulting in a sharper curve. Even in such a case, the straight section allows for stable operation of the conveyor belt and smoother travel. For example, it prevents components of the conveyor belt from getting caught on adjacent frames or other parts.

[0017] In the above-described conveying device, the shape of the curved portion between the first upper guide portion and the second upper guide portion of each conveyor belt is different from the shape of the curved portion between the first lower guide portion and the second lower guide portion, and it is preferable that the curved portion of the return portion has a smaller radius than the curved portion of the conveying portion. With the above configuration, even if the curved portion of the return portion has a smaller radius than the curved portion of the conveying portion, the conveyor belt can be driven smoothly.

[0018] In the above-described conveying device, each conveyor belt is a modular chain including a plurality of belt constituent members and a connecting shaft that connects adjacent ones of the belt constituent members. When the distance between adjacent ones of the connecting shafts is defined as one pitch, it is preferable that the length of the straight portion is set to be at least longer than the one pitch. According to the above configuration, by setting the length of the straight portion to be at least one pitch, the posture of one belt constituent member that constitutes the conveyor belt can be stabilized.

[0019] In the above-described conveying device, it is preferable that at least the conveyor belt positioned on the outermost periphery includes an intermediate straight portion between the first lower transition portion and the second lower transition portion. According to the above configuration, by including the intermediate straight portion, on the return portion side, the shape is such that bulging toward the outer periphery is suppressed, and the device can be miniaturized.

[0020] In the above-described conveying device, it is preferable that all of the plurality of conveyor belts running side by side include an intermediate straight portion between the first lower transition portion and the second lower transition portion, and a driving sprocket with which each conveyor belt meshes is disposed at the position of the intermediate straight portion. According to the above configuration, since the driving sprocket with which each conveyor belt meshes is disposed at the position of the intermediate straight portion, the conveyor belt can run stably in either the forward or reverse direction.

Effects of the Invention

[0021] According to the present invention, in the curved portion, even if the radius is reduced, the running of the conveyor belt can be made smooth.

Brief Description of the Drawings

[0022] [Figure 1] FIG. 1 is a plan view showing a conveying unit in the conveying device described in the first embodiment. [Figure 2] FIG. 2 is a bottom view showing a return unit in the conveying device described in the first embodiment. [Figure 3]FIG. 3 is a front view showing the first winding portion and the first winding portion in the conveying device described in the first embodiment. [Figure 4] FIG. 4 is a side view showing the first winding portion in the conveying device described in the first embodiment. [Figure 5] FIG. 5 is a front view showing the second winding portion in the conveying device described in the first embodiment. [Figure 6] FIG. 6 is a perspective view showing the conveyor belt in the conveying device described in the first embodiment. [Figure 7] FIG. 7 is a plan view showing the conveying device described in the second embodiment.

Embodiments for Carrying out the Invention

[0023] Hereinafter, a belt-type conveying device to which the present invention is applied will be described with reference to the drawings. 〔First Embodiment〕 〔Overall Configuration〕 As shown in FIGS. 1 and 2, the belt-type conveying device 1 in the present embodiment is a device installed in a curved portion 2 with a central angle of 90° in the conveying path. The conveying device 1 includes a plurality of conveyor belts 3 running side by side. Each conveyor belt 3 is an endless belt. A first folding portion 4 is formed at one first end of the curved portion 2 for each conveyor belt 3, and a second folding portion 5 is formed at the other second end.

[0024] The first folding portion 4 includes a first winding portion 6 around which each conveyor belt 3 is wound. The second folding portion 5 includes a second winding portion 7 around which each conveyor belt 3 is wound. Between the first folding portion 4 and the second folding portion 5, the upper side is a conveying portion 8 on which the workpiece is placed and conveyed (see FIG. 1), and the lower side is a return portion 9 of the conveyor belt 3 (see FIG. 2). The conveying portion 8 and the return portion 9 are planes parallel to each other and are configured, for example, as horizontal planes. The first folding portion 4 and the second folding portion 5 are portions connecting the portions between the conveying portion 8 and the return portion 9 and are vertical portions.

[0025] In this embodiment, there are six parallel conveyor belts 3. Each conveyor belt 3 has a longer travel path on its outer circumference than on its inner circumference. The length of each conveyor belt 3 increases sequentially from the inner circumference towards the outer circumference. The innermost conveyor belt 3 has the shortest travel path, while the outermost conveyor belt 3 has the longest.

[0026] In the conveying section 8, each conveyor belt 3 has a first upper transition section 11 adjacent to the first winding section 6, and a second upper transition section 12 adjacent to the second winding section 7 (see Figure 1). That is, in the conveying section 8 of the curved section 2, both ends are the first upper transition section 11 and the second upper transition section 12.

[0027] Furthermore, in the return section 9, the conveyor belt 3 has a first lower transition section 13 adjacent to the first winding section 6, and a second lower transition section 14 adjacent to the second winding section 7 (see Figure 2). In other words, in the return section 9 of the curved section 2, both ends are the first lower transition section 13 and the second lower transition section 14.

[0028] The first upper transition section 11, the second upper transition section 12, the first lower transition section 13, and the second lower transition section 14 are the sections that transition from the curved section 2 to the folded sections 4 and 5. They are also the sections that transition from the folded sections 4 and 5 back to the curved section 2. These transition sections 11 to 14 have a straight section 15.

[0029] In each conveyor belt 3, the straight sections 15 configured in each transition section 11 to 14 include straight sections of the same length. For example, the straight section 15 of the first upper transition section 11 and the straight section 15 of the first lower transition section 13 are the same length. For example, the straight section 15 of the second upper transition section 12 and the straight section 15 of the second lower transition section 14 are the same length. For example, the straight section 15 of the first upper transition section 11 and the straight section 15 of the second upper transition section 12 are the same length. For example, the straight section 15 of the first lower transition section 13 and the straight section 15 of the second lower transition section 14 are the same length. For example, all straight sections 15 are the same length. In this embodiment, the length of the straight section 15 is longer than the distance (1 pitch) between the connecting shafts 32 that connect the belt components 31 constituting the conveyor belt 3, which will be described later (see Figure 6).

[0030] [Wrap-around section] In this embodiment, the first winding portion 6 corresponding to each conveyor belt 3 is the driving side for running the conveyor belt 3, and the second winding portion 7 is the driven side.

[0031] As shown in Figures 3 and 4, the first winding section 6 includes a drive sprocket 16 that engages with the conveyor belt 3, and a first upper guide section 17 and a first lower guide section 18 around which the conveyor belt 3 is wound. The first upper guide section 17 and the first lower guide section 18 are, for example, rollers, or are composed of, for example, guide curved surfaces. The space between the first upper guide section 17 and the first lower guide section 18 is the first folding section 4.

[0032] The first lower guide portion 18 is offset inward from the first upper guide portion 17, i.e., towards the curved portion 2. As a result, the first lower guide portion 18 ensures that the travel path of the conveyor belt 3 between the first upper guide portion 17 and the drive sprocket 16 does not overlap with the travel path between the drive sprocket 16 and the first lower guide portion 18. Therefore, the amount of offset of the first lower guide portion 18 relative to the first upper guide portion 17 is at least the thickness of the conveyor belt 3.

[0033] The first upper guide section 17 is located adjacent to the first upper transition section 11. Furthermore, the first upper guide section 17 is located upstream of the drive sprocket 16 in the direction of travel of the conveyor belt 3 (direction of arrow D1). Six drive sprockets 16 are provided, one for each conveyor belt 3, and are mounted on the same drive shaft 19. The diameter of the drive sprockets 16 corresponding to the outermost conveyor belts 3 is larger than that of the innermost conveyor belts 3. For example, the drive sprocket 16 corresponding to the innermost conveyor belt 3 has the smallest diameter, and the drive sprocket 16 corresponding to the outermost conveyor belt 3 has the largest diameter.

[0034] The drive shaft 19 is connected to a drive source 19a, such as a drive motor, via a drive transmission mechanism consisting of multiple gears, pulleys, and an endless belt. Each conveyor belt 3 travels in one direction (direction of arrow D1) when the drive source 19a is driven. In this embodiment, it does not travel in the opposite direction of arrow D1 under normal use.

[0035] As shown in Figure 5, the second winding section 7 includes an idler wheel 21 around which each conveyor belt 3 is wound, and a second upper guide section 22 and a second lower guide section 23 around which each conveyor belt 3 is wound. The second upper guide section 22 and the second lower guide section 23 are, for example, rollers, or are composed of, for example, guide curved surfaces. The space between the second upper guide section 22 and the second lower guide section 23 is the second folding section 5.

[0036] The second lower guide portion 23 is offset inward, i.e., towards the curved portion, compared to the second upper guide portion 22. As a result, the second lower guide portion 23 ensures that the travel path of the conveyor belt 3 between the second upper guide portion 22 and the idler wheel 21 does not overlap with the travel path between the idler wheel 21 and the second lower guide portion 23. Therefore, the amount of offset of the second lower guide portion 23 relative to the second upper guide portion 22 is at least the thickness of the conveyor belt 3.

[0037] The second upper guide section 22 is located adjacent to the idler wheel 21 of the second upper transition section 12. The second upper guide section 22 is also located downstream of the tension section 25 in the direction of travel of the conveyor belt 3 (direction of arrow D1). Six idler wheels 21 are provided, corresponding to each conveyor belt 3, and are mounted on the same shaft member 24. For example, all idler wheels 21 have the same diameter.

[0038] [Tension section] The shaft member 24 is provided in the tension section 25. The tension section 25 applies appropriate tension to each conveyor belt 3 in order to suppress slack in each conveyor belt 3. The tension section 25 is provided in the second winding section 7, which is located downstream of the drive sprocket 16 in the direction of travel of the conveyor belt 3 (direction of arrow D1).

[0039] The tensioning unit 25 is equipped with a tensioning unit for adjusting the tension of the conveyor belt. The tension adjustment unit 26 is equipped with a cylinder mechanism that moves the idler wheel 21 relative to the conveyor belt 3 in directions that increase and decrease tension. The cylinder mechanism comprises a cylinder 26a and a shaft 26b to which the idler wheel 21 is attached. A biasing member, such as a coil spring, is arranged around the shaft 26b. Inside the cylinder, the biasing member biases the idler wheel 21 in the direction that increases tension with a predetermined biasing force.

[0040] The cylinder mechanism may be hydraulic or pneumatic. Furthermore, the tension unit 25 may be equipped with a tension detection unit that detects fluctuations in the load and rotational speed of the motor constituting the drive source 19a, and the shaft 26b may be moved in a direction that increases or decreases the tension of the idler wheel 21 according to the detected value.

[0041] [Shape of the transport and return sections] Incidentally, the conveying section 8 has straight sections 15 at the first upper transition section 11 and the second upper transition section 12 at both ends, and a curved shape is formed in the area inside these sections (see Figure 1). In contrast, the return section 9 has straight sections 15 at the first lower transition section 13 and the second lower transition section 14 at both ends, and a curved shape is formed in the area inside these sections, but the curved shape inside differs between the inner circumference and the outer circumference (see Figure 2). In the return section 9, the innermost conveyor belt 3 is composed solely of a curved shape. The conveyor belts 3 on the outer circumference side of the innermost conveyor belt 3 have an intermediate straight section 27 in the central part. The intermediate straight section 27 is made longer as it moves towards the outer circumference. That is, in the curved section 2, the travel path of each conveyor belt 3 is shortest at the innermost circumference and becomes longer as it moves towards the outer circumference. Therefore, the innermost conveyor belt 3 has the shortest travel path, and no intermediate straight section 27 is provided there. Intermediate straight sections 27 are provided on the conveyor belt 3 further outwards. As the travel path of the conveyor belt 3 becomes progressively longer towards the outer circumference, the intermediate straight sections 27 also become progressively longer towards the outer circumference accordingly.

[0042] The shapes of the transport section 8 and the return section 9 are different. Firstly, the first lower guide section 18 and the second lower guide section 23 are offset from the first upper guide section 17 and the second upper guide section 22 towards the curved section 2. As a result, the length of the travel path of the return section 9 is shorter than the length of the travel path of the transport section 8, and consequently, the shapes of the transport section 8 and the return section 9 are different. Secondly, the transport section 8 does not have an intermediate straight section 27, while it is provided only in the return section 9. In this respect as well, the shapes of the transport section 8 and the return section 9 are different.

[0043] [Conveyor belt configuration] As shown in Figure 6, each conveyor belt 3 is a modular chain. Each conveyor belt 3 comprises a plurality of belt components 31 and a plurality of connecting shafts 32. Furthermore, the conveyor belt 3 is connected by the connecting shafts 32 in a circular fashion such that adjacent belt components 31 in the direction of arrow D1 have a predetermined length, thereby forming an endless belt.

[0044] Each belt component 31 includes a connecting portion 33 and a hinge piece 34. The hinge pieces 34 are paired by adjacent hinge pieces 34, and the hinge pieces 34 are connected by the connecting portion 33. The pair of hinge pieces 34 are spaced apart, forming a U-shaped space 35 between them. The tip of each hinge piece 34 is provided with an axial hole 36. In the direction of arrow D1, a hinge piece 34 of the belt component 31 that will be connected is inserted into the space 35. When a hinge piece 34 of the belt component 31 that will be connected is inserted into the space 35 between the hinge pieces 34 of one belt component 31, the axial holes 36 of each hinge piece 34 align and the connecting shaft 32 is inserted. The width of the space 35 between the pair of hinge pieces 34 is greater than the thickness of the hinge piece 34 being inserted. Therefore, the pair of hinge pieces 34 that constitute the space 35 and the hinge piece 34 inserted into the space 35 formed between the pair of hinge pieces 34 have play in the W direction. In addition, there is a similar amount of play equal to the gap between the connecting shaft 32 and the shaft hole 36. As a result, each conveyor belt 3 can bend in the W direction and travel along the curved section 2.

[0045] The conveyor belt 3 is guided by running rails 37 provided on the frame side. The running rails 37 are elongated plate members and are provided on the running path of each conveyor belt 3. The running rails 37 are located between the first return section 4 and the second return section 5, and are provided corresponding to the transport section 8 and the return section 9, respectively. Specifically, in the transport section 8, the running rails 37 are provided between the first upper guide section 17 and the second upper guide section 22. Also, in the return section 9, the running rails 37 are provided between the first lower guide section 18 and the second lower guide section 23.

[0046] The running rail 37 located in the transport section 8 has straight sections corresponding to the straight section 15 of the first upper transition section 11 and the straight section 15 of the second upper transition section 12. The running rail 37 located in the return section 9 also has straight sections corresponding to the straight section 15 of the first lower transition section 13 and the straight section 15 of the second lower transition section 14.

[0047] Each belt component 31 is provided with L-shaped engaging guide pieces 38 on both sides in the W direction. The pair of engaging guide pieces 38 engage with both sides of the running rail 37. This allows each conveyor belt 3 to travel along the running rail 37.

[0048] Furthermore, when the distance between adjacent connecting shafts 32 is defined as 1 pitch P, each of the straight sections 15 described above is set to a length of at least 1 pitch P. This allows the posture of the conveyor belt 3 to be stabilized in units of belt components 31 when each conveyor belt 3 enters the return sections 4 and 5 from the curved section 2 and when it enters the curved section 2 from the return sections 4 and 5.

[0049] With the conveyor belt 3 configured as described above, if, for example, a part of it is damaged, only the damaged belt component 31 needs to be replaced. This makes the conveyor belt 3 easy to repair and extends its lifespan. Furthermore, repair is performed by inserting the hinge piece 34 of the belt component 31 that is connected to the other belt component 31 into the space 35 between the pair of hinge pieces 34 and inserting the connecting shaft 32 into the shaft hole 36. Therefore, the repair work on the conveyor belt 3 is also easy.

[0050] [Operation of the First Embodiment] When the drive source 19a starts driving, each conveyor belt 3 travels in the direction of arrow D1. At this time, each conveyor belt 3 sent out from the drive sprocket 16 of the first winding section 6 stabilizes its posture in the straight section 15 of the first lower transition section 13 before being sent out to the curved section 2 of the return section 9. Furthermore, each conveyor belt 3 traveling through the curved section 2 of the return section 9 stabilizes its posture in the straight section 15 of the second lower transition section 14 before entering the second winding section 7. Moreover, each conveyor belt 3 sent out from the second winding section 7 stabilizes its posture in the straight section 15 of the second upper transition section 12 before being sent out to the curved section 2 of the transport section 8. Furthermore, each conveyor belt 3 traveling through the curved section 2 stabilizes its posture in the straight section 15 of the first upper transition section 11 before entering the first winding section 6. Each conveyor belt 3 traveling in the direction of arrow D1 has its tension adjusted by the tension section 25 of the second winding section 7, which is located downstream of the first winding section 6, which is the drive side, thereby suppressing slack.

[0051] [Effects of the First Embodiment] (1-1) In the straight section 15, the posture of the conveyor belt 3 is stable relative to the winding sections 6 and 7 located in front of or behind the straight section 15, and as a result, the movement of the conveyor belt 3 can be made smoother. Therefore, even if the radius of the curved section 2 is made smaller and sharper, the conveyor belt 3 can be made to move smoothly. For example, at the boundary between the folded sections 4 and 5 and the curved section 2, the belt components 31 can be made less likely to get caught on parts such as the frame 28.

[0052] (1-2) Specifically, the conveyor belt 3 sent out from the first winding section 6 can be stabilized in the straight section 15 of the first lower transition section 13 before being sent out to the curved section 2 of the return section 9. For example, the curved section 2 of the return section 9 has a smaller radius than the curved section 2 of the transport section 8. Even in such a location, the belt components 31 are less likely to get caught on parts such as the frame 28 at the boundary between the first folding section 4 and the curved section 2.

[0053] (1-3) The posture of the conveyor belt 3 can be stabilized before and after the drive sprocket 16. The straight section 15 provided in the first upper transition section 11 can stabilize the posture of the conveyor belt 3 just before it enters the first winding section 6 from the curved section 2 of the conveying section 8. This makes it possible to suppress tooth skipping on the drive sprocket 16 of the conveyor belt 3.

[0054] (1-4) The straight section 15 of the second lower transition section 14 can stabilize the posture of the conveyor belt 3 just before it enters the second winding section 7 from the curved section 2 of the return section 9. As a result, the straight section 15 of the second lower transition section 14 can reliably engage the conveyor belt 3 with the second winding section 7.

[0055] (1-5) The straight section 15 of the second upper transition section 12 stabilizes the posture of the conveyor belt 3 that has been fed out from the second winding section 7 before it is fed into the curved section 2 of the transport section 8. This makes it possible to smooth the movement of the conveyor belt 3. For example, in the transport section 8, the belt components 31 are less likely to get caught on parts such as the frame 28 at the boundary between the second folding section 5 and the curved section 2.

[0056] (1-6) The tension section 25 suppresses slack in each conveyor belt and maintains appropriate tension. This allows the conveyor belt 3 to run stably without slack.

[0057] (1-7) The first lower guide section 18 is offset relative to the first upper guide section 17 towards the drive sprocket 16 side or the curved section 2 side. Also, the second lower guide section 23 is offset relative to the second upper guide section 22 towards the idler wheel 21 side or the curved section 2 side. As a result, the length of the travel path on the return section 9 side of each conveyor belt 3 is shorter than the length of the travel path on the transport section 8 side.

[0058] In other words, the length of the curved section 2 between the first lower guide section 18 and the second lower guide section 23 of the conveyor belt 3 in the return section 9 is shorter than the length of the curved section 2 between the first upper guide section 17 and the second upper guide section 22 of the conveyor belt 3 in the transport section 8. As a result, the radius of the curved section 2 on the return section 9 side is smaller than the radius of the curved section 2 on the transport section 8 side, resulting in a sharper curve. Even in such a case, the straight section 15 provides stability to the conveyor belt 3 and facilitates smooth movement.

[0059] (1-8) By making the shape of the transport section 8 and the shape of the return section 9 different, the radius of the curved section 2 on the return section 9 side can be made smaller than the radius of the curved section 2 on the transport section 8 side, and the device can be made smaller by this amount.

[0060] (1-9) By making the length of the straight section 15 at least one pitch P, the posture can be stabilized in units of one belt component 31 that makes up the conveyor belt 3. (1-10) In the return section 9, the intermediate straight section 27 is provided, which reduces the bulge toward the outer circumference, and as a result the device can be made smaller.

[0061] (1-11) As shown in Patent Document 2, the first upper guide portion 17, the first lower guide portion 18, the second upper guide portion 22, and the second lower guide portion 23 can be constructed from highly versatile materials without using a conical roller.

[0062] [Second Embodiment] Figure 7 shows a conveying device 51 of the second embodiment. In the second embodiment, all of the parallel conveyor belts 3 are provided with an intermediate straight section 52 between the first lower transition section 13 and the second lower transition section 14. A drive sprocket 54 is positioned at the location of the intermediate straight section 52, with which each conveyor belt 3 meshes.

[0063] In the curved section 2, the travel path of each conveyor belt 3 is shortest at the innermost circumference and becomes longer towards the outer circumference. The travel path of the innermost conveyor belt 3 is the shortest. In the second embodiment, an intermediate straight section 52 is also provided in the travel path of the innermost conveyor belt 3. The intermediate straight section 52 is configured to become longer towards the outer circumference. Accordingly, the intermediate straight section 52 also becomes progressively longer towards the outer circumference.

[0064] In the conveying device 51, the configuration of the conveying section 8 is the same as in the first embodiment, with straight sections 15 provided at each of the first upper transition section 11 and the second upper transition section 12, which are both ends of the curved section 2. Similarly, in the configuration of the return section 9, straight sections 15 are provided at each of the first lower transition section 13 and the second lower transition section 14.

[0065] The configuration of the first winding section 6 in the first folding section 4 and the second winding section 7 in the second folding section 5 is the same as the configuration of the second winding section 7 in the first embodiment. That is, the first winding section 6 comprises an idler wheel and a first upper guide section and a first lower guide section around which each conveyor belt 3 is wound. The second winding section 7 comprises a second upper guide section and a second lower guide section around which each conveyor belt 3 is wound.

[0066] The winding portion provided at the location of the intermediate straight section 52 is the drive-side winding portion 53. The drive-side winding portion 53 is provided at a location other than both ends of the intermediate straight section 52, for example, in the center. That is, the drive-side winding portion 53 is provided at a location where straight sections are formed on both sides of the drive-side winding portion 53. The drive-side winding portion 53 is provided on a virtual straight line that passes through the center of the curved section 2 and extends radially.

[0067] The drive-side winding section 53 is equipped with drive sprockets 54. Six drive sprockets 54 are provided, one for each conveyor belt 3, and are mounted on the same drive shaft 55. Each drive sprocket 54 has a larger diameter for the outer conveyor belt 3 than for the inner conveyor belt 3. The drive shaft 55 is connected to a drive source 56, such as a drive motor, via a drive transmission mechanism. A tension section may be provided in at least one of the first winding section 6 and the second winding section 7.

[0068] In the conveying device 51 configured as described above, the conveyor belt 3 can travel not only in the direction of arrow D1, but also in the direction of arrow D2, which is opposite to the direction of arrow D1. This is because, regardless of whether the conveyor belt 3 travels in the direction of arrow D1 or arrow D2, sufficient straight sections are provided before and after the drive sprocket 54, which suppresses the occurrence of tooth skipping in the drive sprocket 54.

[0069] [Variation] Furthermore, the above-described transport device may also be in the form of the modified examples shown below, or a combination of at least two mutually non-contradictory modified examples.

[0070] In the second embodiment, the position where the drive-side winding portion 53 is provided is on a virtual straight line that passes through the center of the curved portion 2 and extends radially, so the lengths of the straight portions on both sides of the drive sprocket 54 may be different.

[0071] In the first embodiment, the return section 9 may consist only of a curved shape and not have an intermediate straight section 27. The intermediate straight section 27 may be provided only on the travel path of the outermost conveyor belt 3, or it may be provided only in two sections on the travel path of the conveyor belt 3 from the outer side. Alternatively, an intermediate straight section 27 may also be provided on the travel path of the innermost conveyor belt 3.

[0072] In the first and second embodiments, the four straight sections 15 may all have different lengths, as long as they have a length of at least one pitch P. The length of the straight sections 15 can be set appropriately according to the layout of the conveying device 1 and the central angle of the curved section.

[0073] The length of each straight section 15 may be shorter than the length of one pitch P. For example, at least one of the straight sections 15 in the four transition sections 11 to 14 may be shorter than the length of one pitch P. Even in such a case, it is preferable that at least one straight section 15 has a length longer than one pitch P.

[0074] In the second embodiment, at least one of the first winding portion 6 and the second winding portion 7 may consist only of a guide portion made up of rollers or guide curved surfaces. In the first embodiment as well, the second winding portion 7, which is the driven side, may also consist only of a guide portion made up of rollers or guide curved surfaces.

[0075] In the first and second embodiments, the tensioning portion 25 may be omitted. In the first and second embodiments, if a straight section 15 is provided in any one of the transition sections 11 to 14, the other straight sections 15 may be omitted.

[0076] The central angle of curved section 2 is not limited to 90 degrees. Furthermore, the radius of curved section 2 may be a combination of multiple values. The belt component 31 is not limited to being made of resin, but may also be made of metal.

[0077] The connecting shaft 32 is not limited to being made of resin; it may also be made of metal. The number of parallel conveyor belts 3 is not particularly limited, as long as there are multiple belts. [Explanation of Symbols]

[0078] 1…Conveyor device 2…Curved section 3…Conveyor belt 4…First turnaround section 5…Second turning point 6…First winding section 7...Second winding section 8…Conveyor Unit 9…Return section 11…First upper transition section 12...Second upper transition section 13...First lower transition part 14…Second lower transition part 15…Straight section 16… Drive sprocket 17…First upper guide section 18…First lower guide section 19…Drive shaft 21… Idler Wheel 22...Second upper guide section 23...Second lower guide section 24...Shaft member 25...Tension section 27...Intermediate straight section 28...frames 31... Belt component 32...Connection shaft 37… Rails 38…Engaging guide piece

Claims

1. In a conveying device in which multiple conveyor belts run parallel to each other in a curved section, Each conveyor belt is wrapped around a first winding section which forms a first folding section, Each conveyor belt is wrapped around a second winding section which forms a second folded section, Each conveyor belt has a conveying section on the upper side and a return section on the lower side with respect to the first and second folding sections. The portion adjacent to the first winding portion in the transport section is the first upper transition section, the portion adjacent to the second winding portion in the transport section is the second upper transition section, the portion adjacent to the first winding portion in the return section is the first lower transition section, and the portion adjacent to the second winding portion in the return section is the second lower transition section. At least one of the first upper transition section, the second upper transition section, the first lower transition section, and the second lower transition section has a straight section. Conveying device.

2. The first winding portion is on the drive side and includes a drive sprocket between the first upper transition portion and the first lower transition portion, with each conveyor belt engaging. The second winding section is on the driven side and includes an idler around which each conveyor belt is wound, between the second upper transition section and the second lower transition section. Each conveyor belt travels in the direction from the first winding section to the second winding section in the return section, and travels in the direction from the second winding section to the first winding section in the transport section. The straight portion is provided at least in the first upper transition portion. The conveying device according to claim 1.

3. Furthermore, the straight portion is also provided in the first lower transition portion. The conveying device according to claim 2.

4. Furthermore, the straight section is also provided in the second lower transition section. The conveying device according to claim 2.

5. Furthermore, the straight section is also provided in the second upper transition section. The conveying device according to claim 2.

6. The first winding portion comprises a first upper guide portion provided adjacent to the first upper transition portion, and a first lower guide portion provided adjacent to the first lower transition portion. The second winding portion comprises a second upper guide portion provided adjacent to the second upper transition portion, and a second lower guide portion provided adjacent to the second lower transition portion. The first lower guide portion is offset towards the curved portion side compared to the first upper guide portion. The second lower guide portion is offset towards the curved portion compared to the second upper guide portion. The straight portion is provided in at least one of the first lower transition portion and the second lower transition portion. The conveying device according to claim 1.

7. The shape of the curved portion between the first upper guide portion and the second upper guide portion in each conveyor belt is different from the shape of the curved portion between the first lower guide portion and the second lower guide portion. The curved portion of the return section has a smaller radius than the curved portion of the transport section. The conveying device according to claim 6.

8. Each conveyor belt is a modular chain comprising multiple belt components and connecting shafts that connect adjacent belt components. When the distance between adjacent connecting shafts is defined as one pitch, the length of the straight section is set to be at least longer than one pitch. A conveying device according to any one of claims 1, 2, or 6.

9. At least the outermost part of the conveyor belt has an intermediate straight section between the first lower transition section and the second lower transition section. The conveying device according to claim 1.

10. All of the parallel conveyor belts are provided with an intermediate straight section between the first lower transition section and the second lower transition section. At the location of the aforementioned intermediate straight section, drive sprockets that engage with each conveyor belt are positioned. The conveying device according to claim 1.

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