Article transfer device

Abstract

To provide an article transfer device that can reduce the generation of particles.SOLUTION: An article transfer device (1) has a lifting platform (20) movable along a pillar (10), a toothed belt (30) stretched from the lifting platform along the pillar, a first pulley (41) provided on one side in the vertical direction to the lifting platform, a second pulley (42) provided on the other side, and a drive unit (50) that rotationally drives the first pulley. The second pulley is a flat pulley.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an article transport device that transports articles. [Background technology]

[0002] Patent Document 1 discloses an article transport device for transporting articles. In this article transport device, a lifting platform that is guided by four lifting guide masts and can be raised and lowered is suspended and supported by four cords. Toothed belts as the four cords are wound around toothed pulleys that are provided at the upper ends of the lifting guide masts and serve as driven rotors, and toothed pulleys that are provided at the lower ends of the lifting guide masts and are driven by lifting drive devices. [Prior art documents] [Patent documents]

[0003] Japanese Patent Application Laid-Open No. 2014-97858 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have found that in such an article transport device, the toothed belt wears as the driving time increases, causing the problem of particles being generated from the material of the toothed belt.

[0005] An object of one aspect of the present invention is to provide an article transport device that can reduce particle generation. [Means for solving the problem]

[0006] In order to solve the above problem, an item transport device according to one embodiment of the present invention comprises a support pillar whose longitudinal direction is the vertical direction, a lifting platform that is movable in the vertical direction along the support pillar, a toothed belt that is stretched in both the upward and downward directions from the lifting platform along the support pillar, a first pulley that is mounted on the support pillar on one side of the lifting platform in the vertical direction and around which the toothed belt is wound, a second pulley that is mounted on the support pillar on the other side of the lifting platform in the vertical direction and around which the toothed belt is wound, and a drive unit that rotates and drives the first pulley, wherein the first pulley is a toothed pulley that meshes with the toothed belt and the second pulley is a flat pulley. [Effects of the Invention]

[0007] According to an aspect of the present invention, the item transport device can reduce particle generation. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a front view showing an outline of an article transport device according to a first embodiment. [Figure 2] FIG. 3 is a cross-sectional view of the vicinity of a first pulley. [Figure 3] FIG. 3 is a cross-sectional view of the vicinity of a second pulley. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment 1] An embodiment of the present invention will be described in detail below. In the following description, for convenience of explanation, the up-down direction and the left-right direction are defined as shown by arrows in FIG. 1 and the like. In this embodiment, the up-down direction corresponds to the vertical direction. The left-right direction is a direction perpendicular to the up-down direction. Furthermore, "A to B" indicating a numerical range means "greater than or equal to A and less than or equal to B" unless otherwise specified.

[0010] FIG. 1 is a front view showing an outline of an article transport apparatus 1 according to a first embodiment. The article transport apparatus 1 is an apparatus that transports an object in the vertical direction. Specifically, the article transport apparatus 1 may be an article lifting device provided in a stocker or automated warehouse, or a stacker crane installed in an automated warehouse. As shown in FIG. 1, the article transport apparatus 1 includes a support 10, a lifting platform 20, a toothed belt 30, a first pulley 41, a second pulley 42, a drive unit 50, and a counterweight 60. Furthermore, the article transport apparatus 1 includes a known configuration (not shown) for controlling the elevation of the lifting platform 20.

[0011] The pillars 10 are columnar members whose longitudinal direction is the up-down direction when the item transport apparatus 1 is in use. The item transport apparatus 1 is provided with two pillars 10. The two pillars 10 are spaced apart from each other in the left-right direction. However, the number of pillars 10 provided in the item transport apparatus 1 is not limited to two. An upper frame 11 is provided above the two pillars 10. The upper frame 11 is provided so as to connect the upper ends of the two pillars 10.

[0012] The lifting platform 20 is a member on which an object to be transported by the article transport device 1 is placed. The lifting platform 20 is located between two support columns 10. The lifting platform 20 is provided so as to be movable up and down along the support columns 10. In FIG. 1, the lifting platform 20 located at the bottom of the movable range is shown by a solid line. Also in FIG. 1, the lifting platform 20 located at the top of the movable range is shown by a dashed dotted line.

[0013] The toothed belt 30 is stretched upward and downward from the lifting platform 20 along the support columns 10. Specifically, the lifting platform 20 has a lifting frame 21 on each of its left and right sides. The lifting frame 21 has a structure that can clamp the ends of the toothed belt 30 at the top and bottom. The toothed belt 30, with its ends clamped by the lifting frames 21, is stretched upward and downward. The toothed belt 30 is provided on each of the two support columns 10. The toothed belt 30 is driven around the support columns 10, causing the lifting platform 20 to rise and fall along the support columns 10.

[0014] The first pulley 41 and the second pulley 42 are pulleys around which the toothed belt 30 is wound. The first pulley 41 and the second pulley 42 are provided on each of the two support columns 10. The first pulley 41 is provided on the support column 10 on one side in the up-down direction relative to the lifting platform 20. The second pulley 42 is provided on the support column 10 on the other side in the up-down direction relative to the lifting platform 20.

[0015] Fig. 2 is a cross-sectional view of the vicinity of the first pulley 41. Fig. 3 is a cross-sectional view of the vicinity of the second pulley 42. As shown in Fig. 2, the first pulley 41 is a toothed pulley that meshes with the toothed belt 30. On the other hand, as shown in Fig. 3, the second pulley 42 is a flat pulley.

[0016] The driving device 50 drives and rotates the first pulley 41. The driving device 50 is provided on each of the two support columns 10. As described above, the first pulley 41 meshes with the toothed belt 30. Therefore, in conjunction with the rotational driving of the first pulley 41 by the driving device 50, the toothed belt 30 is driven, and the lifting platform 20 moves up and down along the support columns 10.

[0017] The article conveying apparatus 1 does not include a drive device that rotates the second pulley 42. In other words, the second pulley 42 is a driven pulley that rotates by power transmitted from the first pulley 41 via the toothed belt 30. As described above, the second pulley 42 is a flat pulley. Therefore, the second pulley 42 rotates due to friction with the tips of the teeth of the toothed belt 30.

[0018] The contact area between the second pulley 42, which is a flat pulley, and the toothed belt 30 is smaller than the contact area between the second pulley 42 and the toothed belt 30 when the second pulley 42 is a toothed pulley that meshes with the teeth of the toothed belt 30. This reduces wear of the toothed belt 30 due to friction with the second pulley 42. This reduces the generation of particles from the material of the toothed belt 30 due to wear of the toothed belt 30 on the second pulley 42. Furthermore, by using a flat pulley for the second pulley 42, the manufacturing cost of the second pulley 42 is reduced compared to when the second pulley 42 is a toothed pulley.

[0019] In this embodiment, the first pulley 41 is provided on the support 10 on the lower side of the lifting platform 20. In other words, the second pulley 42 is provided on the support 10 on the upper side of the lifting platform 20. Therefore, by reducing the generation of particles at the second pulley 42, the falling of the particles onto the transported object placed on the lifting platform 20 is also reduced.

[0020] When the platform 20 moves, the counterweight 60 moves along the support 10 in the opposite direction to the movement direction of the platform 20. In the article conveying device 1, the platform 20, toothed belt 30, and counterweight 60 form a closed loop. The platform 20 and counterweight 60 are arranged in opposite positions to each other in the loop. Here, "opposite positions" do not need to be completely opposite positions, but may be considered to be substantially opposite positions.

[0021] By providing the article transport apparatus 1 with the counterweight 60, the energy required to move the lifting platform 20 is reduced compared to when the article transport apparatus 1 does not include the counterweight 60. The weight of the counterweight 60 may be determined appropriately by the designer of the article transport apparatus 1, taking into consideration the weight of the lifting platform 20 and the weight of the expected object to be transported. However, the counterweight 60 is not essential for the article transport apparatus 1 and may be omitted.

[0022] The toothed belt 30 may include a first toothed belt 31 and a second toothed belt 32. The first toothed belt 31 is wound around a first pulley 41 to connect the lifting platform 20 and the counterweight 60. The second toothed belt 32 is wound around a second pulley 42 to connect the lifting platform 20 and the counterweight 60. As described above, in this embodiment, the first pulley 41 is located below the lifting platform 20, and the second pulley 42 is located above the lifting platform 20. Therefore, the first toothed belt 31 is tensioned downward from the lifting platform 20 along the support 10. The second toothed belt 32 is tensioned upward from the lifting platform 20 along the support 10.

[0023] In the article conveying apparatus 1, because the toothed belt 30 includes the first toothed belt 31 and the second toothed belt 32, the length of each belt can be shortened compared to, for example, when the toothed belt 30 is a single toothed belt. Therefore, the first toothed belt 31 and the second toothed belt 32 can be procured more easily compared to the toothed belt 30, which is a single toothed belt. Furthermore, when one of the first toothed belt 31 or the second toothed belt 32 wears out, only the worn belt needs to be replaced, which reduces the maintenance costs of the article conveying apparatus 1 compared to replacing the entire toothed belt 30.

[0024] In this embodiment, the first toothed belt 31 and the second toothed belt 32 are separate members having the same shape. Therefore, procurement of parts is easier than when the first toothed belt 31 and the second toothed belt 32 have different shapes. However, the first toothed belt 31 and the second toothed belt 32 do not necessarily have to have the same shape.

[0025] Furthermore, if a flat belt were used instead of the second toothed belt 32, which is a toothed belt, holes would need to be drilled in the flat belt in order to attach the second toothed belt 32 to the lifting frame 21 and the counterweight 60. In the article conveying device 1, by using the second toothed belt 32 and providing the lifting frame 21 and the counterweight 60 with a structure for clamping the second toothed belt 32, the above-mentioned hole drilling that was necessary when using a flat belt is no longer necessary.

[0026] However, the toothed belt 30 does not necessarily have to include the first toothed belt 31 and the second toothed belt 32, and may be, for example, a single toothed belt. In this case, the counterweight 60 may be attached by, for example, clamping the toothed belt 30 from both sides.

[0027] (Experimental example) The inventors of the present application prototyped article transport devices of an example and a comparative example and conducted trial runs. The article transport device of the example was equipped with the second pulley 42, which was the flat pulley described above. The article transport device of the comparative example was equipped with a toothed pulley that meshes with toothed belt 30, similar to first pulley 41, instead of second pulley 42, which was a flat pulley. In the trial runs, the article transport device was operated continuously for 2.5 years, assuming that it would be raised and lowered 1,440 times per day.

[0028] After the trial run, in the article transport device of the comparative example, generation of particles due to wear of the toothed belt 30 was observed around the toothed pulley used in place of the second pulley 42. On the other hand, in the article transport device of the example, generation of particles was not observed around the second pulley 42. Therefore, it can be said that in the article transport device of the example, by using a flat pulley for the second pulley 42, generation of particles was reduced compared to the article transport device of the comparative example.

[0029] Generally, belt-driven devices can have problems with belt meandering. However, in this test run, no significant difference was observed in the amount of meandering of the toothed belt 30 between the article conveying devices of the example and the comparative example. In other words, there was no problem with the amount of meandering of the toothed belt 30 in the article conveying device of the example being greater than the amount of meandering of the toothed belt 30 in the article conveying device of the comparative example.

[0030] [Embodiment 2] In the above-described embodiment, the first pulley 41 and the drive unit 50 are provided on the support 10 on the lower side of the lifting platform 20. However, the first pulley 41 and the drive unit 50 may be provided on the support 10 on the upper side of the lifting platform 20. In other words, the second pulley 42 may be provided on the support 10 on the lower side of the lifting platform 20. In this case as well, generation of particles at the second pulley 42 is reduced.

[0031] However, unlike the second pulley 42, particles may be generated in the first pulley 41 due to wear of the toothed belt 30, as in conventional article conveying devices. If the first pulley 41 and the drive unit 50 are provided above the lifting platform 20, particles generated in the first pulley 41 may fall onto the object being conveyed that is placed on the lifting platform 20. From the perspective of reducing the risk of particles falling onto the object being conveyed, it is preferable that the first pulley 41 and the drive unit 50 be provided below the lifting platform 20, as described in the first embodiment.

[0032] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0033] 1. Item transport device 10 posts 20 Lift Platform 30 Toothed belt 31 First toothed belt 32 Second toothed belt 41 First pulley 42 No. 2 pulley 50 Drive unit 60 Counterweight

Claims

1. A support column having a longitudinal direction as a vertical direction; a lift platform provided so as to be movable in the up-down direction along the support; a toothed belt stretched in an upward and downward direction from the lift platform along the support pillar; a first pulley provided on the support column on one side of the lift platform in the up-down direction, the first pulley being around which the toothed belt is wound; a second pulley provided on the support column on the other side in the up-down direction with respect to the lift platform, the second pulley being around which the toothed belt is wound; a drive device that rotates the first pulley, the first pulley is a toothed pulley that meshes with the toothed belt, An article transport device, wherein the second pulley is a flat pulley.

2. The article transport device according to claim 1 , wherein the first pulley is provided on the support column on a lower side in the up-down direction relative to the lifting platform.

3. A counterweight is further provided which moves in a direction opposite to the moving direction of the lift platform when the lift platform moves. The toothed belt is a first toothed belt that is wound around the first pulley and connects the lift platform and the counterweight; 3. The article transport apparatus according to claim 1, further comprising a second toothed belt that is wound around the second pulley and connects the lift platform and the counterweight.

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