Pallet lifting device, transport device

Abstract

To simultaneously realize both a support of a fed pallet and a sending out of another pallet which has been lifted and lowered in a pallet lifting device.SOLUTION: A pallet lifting device includes a plurality of support parts for supporting, and lifting and lowering a pallet. Each of the support parts has: an arm that extends in a direction perpendicular to a first axis which is a horizontal axis, and rotates around the first axis; and a pair of rollers provided on both ends of the arm. Each of the rollers is configured to be capable of assuming a first position for the rollers to support the pallet, in which the roller axis is perpendicular to a second axis along a longitudinal direction of the arm and the roller axis is parallel to the first axis.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a pallet lifting device that lifts and lowers a pallet loaded with cargo, and a conveying device that includes the pallet lifting device and conveys cargo by conveying the pallet. [Background technology]

[0002] Patent document 1 describes a descending path section and an ascending path section for transporting a cart (pallet) along a guide rail between a conveying path section and a return path section located above and below the cart. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-193480 Summary of the Invention [Problem to be solved by the invention]

[0004] When a conveying device is equipped with a mechanism for raising and lowering pallets, such as the ascending path section described in Patent Document 1, the mechanism cannot load pallets until it returns to a position where it can receive the pallets after raising and lowering the pallets. For this reason, the conveying device requires time to transport multiple pallets up and down. [Means for solving the problem]

[0005] A pallet lifting device according to one embodiment of the present disclosure is a pallet lifting device that raises or lowers a pallet that has been fed at a first height to a second height before sending it out, and is equipped with a plurality of support parts for supporting and raising and lowering the pallet, each of which has an arm that extends in a direction perpendicular to a first axis that is a horizontal axis and rotates around the first axis located in the center of its longitudinal direction, and a pair of rollers provided at both ends of the arm, and each of the rollers is configured so that the roller axis is perpendicular to a second axis along the longitudinal direction of the arm and the roller axis is parallel to the first axis, so that the roller can take a first position for supporting the pallet. [Effects of the Invention]

[0006] To simultaneously realize both the support of a fed pallet and the sending out of another pallet that has been lifted and lowered in a pallet lifting device. [Brief explanation of the drawings]

[0007] [Figure 1] 1A and 1B are enlarged perspective views of a conveying device and a support part according to a first embodiment of the present disclosure. [Figure 2] 1A to 1C are a schematic perspective view, a schematic plan view, and a schematic side view of a conveying device according to a first embodiment of the present disclosure. [Figure 3] FIG. 2 is an enlarged perspective view of a support portion in which one of the rollers is in a second position according to the first embodiment of the present disclosure. [Figure 4] 2A and 2B are a schematic side view and a schematic plan view of a part of a support part according to the first embodiment of the present disclosure. [Figure 5] 4 is a schematic diagram of a part of a support portion and a part of an auxiliary roller guide, illustrating a state in which the roller according to the first embodiment of the present disclosure transitions from a first position to a second position. FIG. [Figure 6] 5 is a schematic diagram of a part of a support portion and a part of an auxiliary roller guide, illustrating a state in which the roller according to the first embodiment of the present disclosure transitions from the second position to the first position. FIG. [Figure 7]10 is a side view of a part of the process of the transport unit, the return unit, and the pallet lifting device in the transfer of the pallet between the transport section or the return section and the pallet lifting device according to the first embodiment of the present disclosure. FIG. [Figure 8] 2 is a schematic side view of each drive roller and each pallet, illustrating the positional relationship between each drive roller and each pallet of the pallet lifting device according to the first embodiment of the present disclosure. FIG. [Figure 9] 1 is an enlarged perspective view of a pallet lifting device showing an example in which a plurality of support parts are connected by a belt according to the first embodiment of the present disclosure. FIG. [Figure 10] FIG. 10 is an enlarged perspective view of a support part according to a second embodiment of the present disclosure. [Figure 11] FIG. 10 is an enlarged side view of one of the support parts and a part of the pallet in a state where the pallet is supported and raised and lowered by a pallet lifting device according to a second embodiment of the present disclosure. [Figure 12] 10A and 10B are enlarged perspective views of a conveying device and a support part according to a third embodiment of the present disclosure. [Figure 13] FIG. 11 is an enlarged side view of a part of a pallet lifting device and a pallet in a state in which the pallet is supported and lifted by the pallet lifting device according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] <Transportation equipment: Overview> In this embodiment, a conveying device that conveys cargo by conveying a pallet loaded with cargo along a fixed route will be described. In particular, the conveying device according to this embodiment is a conveying device that loads a vehicle body such as an automobile on a pallet and conveys the vehicle body. The conveying device according to this embodiment will be described with reference to FIG. 2.

[0009] 2 is a diagram showing a schematic perspective view 202, a schematic plan view 204, and a schematic side view 206 of the conveying device 2 according to this embodiment. Also shown in FIG. 2 is a vehicle body X conveyed by the conveying device 2. The schematic plan view 204 and the schematic side view 206 show enlarged views of the vicinity of a descending section 10 and an ascending section 12, which will be described later, and also omit a portion of the conveying device 2, which is shown in its entirety in the schematic perspective view 202.

[0010] The conveying device 2 includes a pallet 4, a conveying section 6, a return section 8, a descending section 10, and an ascending section 12. The conveying device 2 conveys the pallet 4 along a fixed route using the conveying section 6, the return section 8, the descending section 10, and the ascending section 12. The conveying device 2 also conveys the vehicle body X by using the conveying section 6 to convey the pallet 4 loaded with the vehicle body X, using a method described below.

[0011] <Transportation device: pallet> The pallet 4 is, for example, a plate-like member having a plurality of treads fitted into openings in a frame body. For example, the pallet 4 may be configured so that it can hold the vehicle body X via a jig attached to the frame body, while allowing a worker or the like to move onto the treads and perform work such as assembling parts to the vehicle body X.

[0012] <Transportation device: Transport section> The conveying section 6 conveys the pallet 4 in the conveying direction DT along a conveying path 6W extending in the conveying direction DT. The conveying device 2 loads the vehicle body X on the pallet 4 and conveys the pallet 4 in the conveying direction DT using the conveying section 6, thereby conveying the vehicle body X in the conveying direction DT. The conveying section 6 includes, for example, a plurality of conveying units 6U arranged in the conveying direction DT. The conveying section 6 transports the pallet 4 in the conveying direction DT by repeatedly transferring the pallet 4 from one conveying unit 6U to an adjacent conveying unit 6U in the conveying direction DT.

[0013] A vehicle body X transported by a loading device (not shown) is loaded onto a pallet 4 located at the start of the conveying path 6W. A vehicle body X is removed from a pallet 4 located at the end of the conveying path 6W by a removal device (not shown). A pallet 4 without a vehicle body X is transported to the start of the conveying path 6W by a method described below. The conveying device 2 may, for example, sequentially transport pallets 4 loaded with a vehicle body X located at the start of the conveying path 6W by the conveying unit 6. By this method, the conveying device 2 may simultaneously transport multiple vehicle bodies X by the conveying unit 6. As described above, a worker may transfer onto the pallet 4 transported by the conveying unit 6, and the worker may perform work such as assembling parts onto the transported vehicle body X.

[0014] <Transportation device: Return section> The return unit 8 transports the pallets 4 in the return direction DR along a return path 8W that extends in the return direction DR, which is the opposite direction to the conveying direction DT. For example, the return path 8W is located below the conveying path 6W, and at least a portion of it overlaps with the conveying path 6W in a plan view. Therefore, one of the conveying unit 6 and the return unit 8 transports the pallets 4 at a first height, and the other of the conveying unit 6 and the return unit 8 transports the pallets 4 at a second height.

[0015] The conveying device 2 conveys the pallet 4 to the upstream side of the return path 8W by conveying the pallet 4 in the return direction DR using the return section 8. The return section 8, for example, includes a plurality of return units 8U arranged in the return direction DR. The return section 8 transports the pallet 4 in the return direction DR by repeatedly handing over the pallet 4 from one return unit 8U to an adjacent return unit 8U in the return direction DR.

[0016] <Transportation device: descending section, ascending section> The descending section 10 descends the pallet 4 that has been transported to the end of the transport path 6W, and transfers the pallet 4 from the end of the transport path 6W to the start of the return path 8W. The ascending section 12 ascends the pallet 4 that has been transported to the end of the return path 8W, and transfers the pallet 4 from the end of the return path 8W to the start of the transport path 6W. In this way, the transport device 2 circulates the pallets 4 using the transport section 6, the return section 8, the descending section 10, and the ascending section 12.

[0017] The descending section 10 includes a pallet lifting device 24 adjacent to the transport unit 6U located at the end of the transport path 6W and the return unit 8U located at the start of the return path 8W. The ascending section 12 also includes a pallet lifting device 24 adjacent to the transport unit 6U located at the start of the transport path 6W and the return unit 8U located at the end of the return path 8W. The descending section 10 and the ascending section 12 may be equipped with pallet lifting devices 24 of the same configuration, except for the method of controlling the attitude of the rollers 42, which will be described later.

[0018] <Transportation device: transport unit and return unit> The conveying section 6, the returning section 8, and the pallet lifting device 24 will be described in more detail with reference to Fig. 1. Fig. 1 shows an enlarged perspective view 102 of a portion of the conveying device 2 and an enlarged perspective view 104 of a support section 32, which is part of the pallet lifting device 24 and will be described later.

[0019] The enlarged perspective view 102 is a perspective view particularly showing an enlarged view of the pallet lifting device 24 provided in the ascending section 12 of the conveying device 2, and the conveying unit 6U and the return unit 8U adjacent to the pallet lifting device 24. Each of the conveying section 6 and the return section 8 may be provided with a plurality of conveying units 6U and return units 8U having the same configuration as the conveying unit 6U and the return unit 8U shown in the enlarged perspective view 102. Furthermore, the descending section 10 may be provided with a pallet lifting device 24 having the same configuration as the pallet lifting device 24 shown in the enlarged perspective view 102.

[0020] The transport unit 6U of the transport section 6 has rails 26, rollers 28, and a friction drive unit 30. The rails 26 are arranged along the transport direction DT. The transport unit 6U has two rails 26 arranged at a distance from each other in a direction perpendicular to the transport direction DT and the up-down direction. A plurality of rollers 28 are formed on each rail 26 along the transport direction DT. The rollers 28 are arranged on each rail 26 so that the rollers 28 of the two rails 26 face each other.

[0021] A friction drive unit 30 is disposed on each of the two rails 26. Each friction drive unit 30 has a drive roller 30R with a rotation axis extending in the vertical direction. The two drive rollers 30R are disposed so that the pallet 4 being transported is located between them. In particular, the two drive rollers 30R are disposed so that they sandwich the pallet 4 from the sides and rub against each other against the side surfaces of the pallet 4.

[0022] The rollers 28 are rotatably constrained to a rotation axis extending in a direction perpendicular to the conveying direction DT and the up-down direction. The conveying unit 6U places the pallet 4 on the rollers 28 of each of the two rails 26, thereby supporting the pallet 4 on the rollers 28.

[0023] In this state, the friction drive unit 30 of the transport unit 6U rotates the two drive rollers 30R about their rotation axes while sandwiching the pallet 4 between them. As a result, the friction drive unit 30 sends out the pallet 4 sandwiched between the two drive rollers 30R in the transport direction DT. Here, the friction between each roller 28 and the pallet 4 it supports causes each roller 28 to rotate about its rotation axis. In this way, the transport unit 6U transports the pallet 4 supported by the rollers 28 along the transport path 6W in the transport direction DT.

[0024] The return unit 8U of the return section 8 is located below the transport unit 6U and has the same configuration as the transport unit 6U, except that the rotation direction of each drive roller 30R is opposite. Therefore, the return unit 8U transports the pallet 4 supported by the rollers 28 in the return direction DR along the return path 8W. The transport unit 6U and the return unit 8U may be formed as a single unit by fixing their rails 26 to each other.

[0025] <Pallet lifting device: Overview> As shown in enlarged perspective view 102, pallet lifting device 24 includes a plurality of support parts 32 and a plurality of friction drive units 30. The friction drive units 30 included in pallet lifting device 24 may be the same as the friction drive units 30 included in transport unit 6U and return unit 8U.

[0026] The pallet lifting device 24 provided in the lowering section 10 lowers the pallet 4 sent from the conveying section 6 and sends it to the return section 8. The pallet lifting device 24 provided in the ascending section 12 raises the pallet 4 sent from the return section 8 and sends it to the conveying section 6. In other words, the pallet lifting device 24 is a device that raises or lowers the pallet 4 sent at a first height to a second height and then sends it out.

[0027] In particular, the pallet lifting device 24 supports and raises and lowers the pallets 4 sent from the conveying section 6 or the return section 8 using a plurality of supports 32, and sends them out to the conveying section 6 or the return section 8. Receiving the pallets 4 sent from the conveying section 6 or the return section 8 and sending out the pallets 4 to the conveying section 6 or the return section 8 are performed by the friction drive unit 30.

[0028] The friction drive unit 30 provided in the pallet lifting device 24 drives the pallet 4, for example, as described above, by rotating the drive rollers 30R included in the friction drive unit 30 while the pallet 4 is clamped between them.

[0029] In particular, in this embodiment, the friction drive unit 30 provided in the pallet lifting device 24 includes a drive roller 30R as a first drive roller that drives the pallet 4 sent from either the conveying section 6 or the return section 8. In addition, the friction drive unit 30 provided in the pallet lifting device 24 includes a drive roller 30R as a second drive roller that drives the pallet 4 sent from the other of the conveying section 6 or the return section 8.

[0030] The pallet lifting device 24 has a plurality of pairs of support parts 32 that face each other in a direction perpendicular to the conveying direction DT and the up-down direction of the pallet 4. The plurality of pairs of support parts 32 are aligned in substantially the same direction as the conveying direction DT of the pallet 4. The pairs of support parts 32 are arranged so that their sides of rollers 42, which will be described later, face each other. Each support part 32 is arranged so that, in a plan view, the pallet 4 fed into the pallet lifting device 24 by a method which will be described later, overlaps only with the rollers 42 and roller shafts 44, which will be described later.

[0031] Hereinafter, unless otherwise specified, the pallet lifting device 24 according to this embodiment refers to the pallet lifting device 24 provided in the lifting section 12.

[0032] <Pallet lifting device: Support unit: Overview> The support part 32 will be described in more detail with reference to an enlarged perspective view 104 of the support part 32. Note that in order to more simply and clearly explain each part of the support part 32, some of the members included in the support part 32 may be omitted in each drawing including FIG.

[0033] The support unit 32 includes a shaft 34 extending along a first axis, which is a horizontal axis; a shaft bearing 36 that restrains the shaft 34 so that it can rotate about its longitudinal axis; and a shaft drive unit 38 that includes a motor or the like that drives the rotation of the shaft 34. The shaft 34 extends in a direction perpendicular to the conveying direction DT and the up-down direction. The shaft bearing 36 is fixed, for example, via bolts 36B or the like to a base (not shown) that is fixed to the ground. As a result, the shaft 34 is driven by the shaft drive unit 38 and can rotate in a direction perpendicular to the conveying direction DT and the up-down direction, while its position is fixed relative to the ground.

[0034] <Pallet lifting device: support part: arm and roller> Furthermore, the support unit 32 has an arm 40 fixed to the end of the shaft 34 on the conveying path 6W side, and a pair of rollers 42 provided on both ends of the arm 40. In this embodiment, the support unit 32 has a pair of roller shafts 44 which are rotation axes of the rollers 42, and roller shaft support units 46 on which the roller shafts 44 are formed and which are formed on both ends of the arm 40.

[0035] The arm 40 extends in both the direction of extension of the shaft 34 and the direction perpendicular to the direction of extension of the shaft 34. Therefore, the shaft 34 is located at the center of the arm 40 in the longitudinal direction, and the arm 40 rotates around the direction of extension of the shaft 34 as the shaft 34 rotates. Note that the enlarged perspective view 104 shows the support part 32 in a state in which the arm 40 extends in the vertical direction.

[0036] Each roller 42 is constrained to be rotatable around a roller shaft 44. Each roller shaft 44 is perpendicular to a second axis along the longitudinal direction of the arm 40. Each roller shaft support portion 46 is constrained to the arm 40 to be rotatable around the longitudinal direction of the arm 40. Therefore, the roller shaft 44 of each roller 42 is rotatable around the arm 40, and therefore each roller 42 is also rotatable around the arm 40.

[0037] In this embodiment, each roller 42 is a driven roller that rotates around its roller shaft 44 due to an external force. For example, each roller 42 rotates around its roller shaft 44 due to friction with a pallet 4 that is transported by a method described below. Note that some of the rollers 42 may be drive rollers, but from the viewpoint of reducing the number of drive units for rotating the rollers 42, all of the rollers 42 may be driven rollers.

[0038] For example, the support unit 32 has two rollers 42, namely, roller 42A that rotates around roller shaft 44A and roller 42B that rotates around roller shaft 44B. In particular, the enlarged perspective view 104 shows the support unit 32 in a state in which roller 42A is located at the upper end of the arm 40 and roller 42B is located at the lower end of the arm 40. The support unit 32 also has two roller shaft support units 46, namely, roller shaft support unit 46A where roller shaft 44A is formed and roller shaft support unit 46B where roller shaft 44B is formed.

[0039] As the arm 40 rotates around the shaft 34, the two rollers 42 revolve around the first axis, in other words, around an extension line of the longitudinal direction of the shaft 34. For example, in this embodiment, the support unit 32 shown in the enlarged perspective view 104 rotates the shaft 34 counterclockwise when viewed in the direction from the rollers 42 to the shaft 34 by the shaft driving unit 38. Accordingly, the two rollers 42 revolve counterclockwise around the first axis when viewed in the direction from the rollers 42 to the shaft 34.

[0040] <Pallet lifting device: support part: roller position> Here, enlarged perspective view 104 shows a state in which two rollers 42 are in the first position. When roller 42 is in the first position, roller axis 44 of roller 42 is parallel to the first axis, in other words, parallel to the extension direction of shaft 34. Roller 42 in the first position always maintains the first position regardless of rotation of arm 40 around shaft 34, unless roller 42 rotates around the extension direction of arm 40.

[0041] Each roller 42 can also assume a second position in which the roller shaft 44 rotates together with the roller shaft support portion 46 from the first position around the second axis, in other words, around the extension direction of the arm 40. The rollers 42 in the second position will be described in detail with reference to Figure 3. Figure 3 is another enlarged perspective view of the support portion 32, showing the support portion 32 from the same direction as the enlarged perspective view 104.

[0042] FIG. 3 shows the support portion 32 in a state in which the arm 40 has rotated around the shaft 34 from a state in which it extends in the vertical direction. Therefore, of the two rollers 42, roller 42A has moved downward from the state shown in FIG. 1, and roller 42B has moved upward from the state shown in FIG. 1. Furthermore, as the roller shaft support portion 46A rotates around the arm 40, roller 42A shown in FIG. 3 assumes a second position in which the roller shaft 44A has rotated around the arm 40, while roller 42B maintains the first position. Particularly in this embodiment, roller 42A in the second position is positioned higher on the opposite side than on the side of the arm 40. The second position of roller 42A may be a position in which the roller shaft 44A has rotated about the arm 40 by approximately 90 degrees from the first position.

[0043] <Pallet lifting device: support part: auxiliary roller> The change in the position of the roller 42 according to this embodiment is realized by an auxiliary roller 48 provided in the support portion 32 and an auxiliary roller guide not shown in FIGS.

[0044] The auxiliary rollers 48 include a first auxiliary roller 50 and a second auxiliary roller 52 that are constrained by the roller shaft support portions 46 so as to be rotatable around the extension direction of the arm 40. Therefore, the first auxiliary roller 50 and the second auxiliary roller 52 revolve around the arm 40 in conjunction with the roller shaft 44 as the roller shaft support portions 46 rotate around the arm 40. The first auxiliary roller 50 may be formed directly on the roller shaft support portion 46, and the second auxiliary roller 52 may be formed on the roller shaft support portion 46 via an auxiliary roller support portion 48S.

[0045] In particular, a first auxiliary roller 50A and a second auxiliary roller 52A are formed on roller shaft support portion 46A, and a first auxiliary roller 50B and a second auxiliary roller 52B are formed on roller shaft support portion 46B. Therefore, the first auxiliary roller 50A and the second auxiliary roller 52A revolve around the arm 40 together with roller 42A, and the first auxiliary roller 50B and the second auxiliary roller 52B revolve around the arm 40 together with roller 42B. In enlarged perspective view 104, the first auxiliary roller 50B is shown by a dotted line to indicate that it is located on the far side of roller 42B when facing the plane of the page.

[0046] <Pallet lifting device: Support part: Auxiliary roller guide> The auxiliary roller guide guides the auxiliary roller 48 to alternately change the position of the roller 42 between the first position and the second position as the arm 40 rotates around the shaft 34. The specific configuration of the auxiliary roller guide will be described in further detail with reference to FIG. 4. FIG. 4 shows a schematic side view 402 and a schematic plan view 404 of one support unit 32, illustrating an extracted portion of the support unit 32. In particular, the schematic side view 402 and the schematic plan view 404 illustrate extracted portions of the shaft 34, the arm 40, the roller 42, the roller shaft support unit 46, the auxiliary roller 48, and the auxiliary roller guide 54 of one support unit 32. The schematic side view 402 illustrates a portion of the support unit 32 as viewed from the arm 40 side in the extension direction of the shaft 34.

[0047] The auxiliary roller guide 54 includes a first guide portion 56 , a second guide portion 58 , a third guide portion 60 , a fourth guide portion 62 , a first guide support portion 64 , and a second guide support portion 66 .

[0048] The first guide portion 56, the second guide portion 58, the third guide portion 60, and the fourth guide portion 62 are plate-like members whose surfaces rub against the outer circumferential surface of the auxiliary roller 48 as the arm 40 rotates around the shaft 34, as will be described later. In particular, the first guide portion 56, the second guide portion 58, the third guide portion 60, and the fourth guide portion 62 are positioned so as to overlap with the path trajectory of the outer circumferential surface of the auxiliary roller 48 when the arm 40 rotates around the shaft 34, when viewed from the arm 40 side in the extension direction of the shaft 34. For example, the first guide portion 56, the second guide portion 58, the third guide portion 60, and the fourth guide portion 62 have their longitudinal directions in the circumferential direction centered on the shaft 34.

[0049] The first guide portion 56 and the second guide portion 58 are fixed to the first guide support portion 64, and the third guide portion 60 and the fourth guide portion 62 are fixed to the second guide support portion 66. The first guide support portion 64 and the second guide support portion 66 are fixed in position relative to the ground. Therefore, the positions of the first guide portion 56, the second guide portion 58, the third guide portion 60, and the fourth guide portion 62 are fixed regardless of rotation of the arm 40 around the shaft 34.

[0050] The first guide part 56 has a first protrusion 68 at its upper longitudinal end that protrudes in the direction from the shaft 34 to the arm 40. The second guide part 58 has a second protrusion 70 at its lower longitudinal end that protrudes in the direction from the arm 40 to the shaft 34.

[0051] <Pallet lifting device: Support part: Guide of roller from first position to second position> The change of roller 42 between the first position and the second position via the guidance of auxiliary roller 48 by auxiliary roller guide 54 will be described with reference to Figures 5 and 6. Figure 5 is a schematic diagram showing how roller 42A changes from the first position to the second position, and Figure 6 is a schematic diagram showing how roller 42A changes from the second position to the first position. Both the schematic diagrams shown in Figures 5 and 6 are schematic diagrams of roller 42A and the vicinity of roller 42A viewed in the direction from roller 42A toward roller shaft support portion 46A in the longitudinal direction of roller shaft 44A.

[0052] 4 is in the vertical direction, and roller 42A is in the first position. Rotation of shaft 34 causes roller 42A to move leftward as viewed in schematic diagram 502. Here, first protrusion 68 of first guide part 56 is located on the path of first auxiliary roller 50A, which moves in conjunction with the movement of roller 42A due to rotation of shaft 34.

[0053] Schematic diagram 504 shows a state in which shaft 34 has rotated from the state shown in schematic diagram 502. As shown in schematic diagram 504, first auxiliary roller 50A comes into contact with first protrusion 68 as shaft 34 rotates and roller 42A moves.

[0054] Schematic diagram 506 shows a state in which the shaft 34 has rotated further from the state shown in schematic diagram 504. As the shaft 34 rotates further from the state in which the first auxiliary roller 50A and the first protrusion 68 are in contact, the end of the arm 40 on the roller 42A side continues to move, while the movement of the first auxiliary roller 50A is prevented by the first protrusion 68. As a result, as shown in schematic diagram 506, the first auxiliary roller 50A is pressed by the first protrusion 68, and as a result, the roller shaft support portion 46A rotates around the arm 40. As a result, the roller shaft 44A and roller 42A rotate around the arm 40 together with the roller shaft support portion 46A.

[0055] Schematic diagram 508 shows a state in which the shaft 34 has rotated further from the state shown in schematic diagram 506. As shown in schematic diagram 508, when the shaft 34 rotates until the first auxiliary roller 50A passes over the first protrusion 68, the outer peripheral surface of the first auxiliary roller 50A rubs against the side surface of the first guide portion 56, causing the first auxiliary roller 50A to start rotating on its axis.

[0056] Furthermore, as shown in schematic diagram 508, when the shaft 34 rotates until the first auxiliary roller 50A passes over the first protrusion 68, the roller shaft support portion 46A rotates around the arm 40 to a position where the longitudinal direction of the roller shaft 44A is perpendicular to the longitudinal direction of the shaft 34. As a result, the posture of the roller 42A changes from the first posture shown in schematic diagram 502 to the second posture shown in schematic diagram 508.

[0057] While the roller 42A is in the second position, the outer circumferential surface of the second auxiliary roller 52A rubs against the side surface of the second guide portion 58, causing the second auxiliary roller 52A to rotate. While the outer circumferential surface of the second auxiliary roller 52A rubs against the second guide portion 58, the position of the roller 42A is maintained in the second position.

[0058] <Pallet lifting device: Support part: Guide of roller from second position to first position> Schematic diagram 602 shows a state in which the shaft 34 has further rotated from the state shown in schematic diagram 508. As the shaft 34 continues to rotate from the state shown in schematic diagram 508, the second auxiliary roller 52A moves to the end of the second guide portion 58 on the side of the third guide portion 60. Here, the second protrusion 70 of the third guide portion 60 is positioned on the path of the second auxiliary roller 52A.

[0059] Schematic diagram 604 shows a state in which shaft 34 has rotated from the state shown in schematic diagram 602. As shown in schematic diagram 604, as shaft 34 rotates and roller 42A moves, second auxiliary roller 52A moves away from second guide portion 58 and comes into contact with second protrusion 70.

[0060] Schematic diagram 606 shows a state in which the shaft 34 has rotated further from the state shown in schematic diagram 604. As the shaft 34 rotates further from the state in which the second auxiliary roller 52A and the second protrusion 70 are in contact, the end of the arm 40 on the roller 42A side continues to move, while the movement of the second auxiliary roller 52A is prevented by the second protrusion 70. As a result, as shown in schematic diagram 606, the second auxiliary roller 52A is pressed by the second protrusion 70, and as a result, the roller shaft support portion 46A rotates around the arm 40. As a result, the roller shaft 44A and roller 42A rotate around the arm 40 together with the roller shaft support portion 46A.

[0061] Schematic diagram 608 shows a state in which the shaft 34 has rotated further from the state shown in schematic diagram 606, and in particular, shows a state in which the shaft 34 has rotated to a position in which the arm 40 again extends substantially in the vertical direction. As shown in schematic diagram 608, when the shaft 34 has rotated until the second auxiliary roller 52A passes over the second protrusion 70, friction occurs between the outer peripheral surface of the second auxiliary roller 52A and the side surface of the third guide part 60, causing the second auxiliary roller 52A to start rotating on its own axis.

[0062] Furthermore, as shown in schematic diagram 608, when the shaft 34 rotates until the second auxiliary roller 52A passes over the second protrusion 70, the roller shaft support portion 46A rotates around the arm 40 to a position where the longitudinal direction of the roller shaft 44A is parallel to the longitudinal direction of the shaft 34. As a result, the posture of the roller 42A changes from the second posture shown in schematic diagram 602 to the first posture shown in schematic diagram 608.

[0063] <Pallet lifting device: Support part: Additional information on roller attitude control> If the shaft 34 rotates further from the state shown in schematic diagram 608, the second auxiliary roller 52A continues to rub against the side surface of the third guide portion 60, and the first auxiliary roller 50A rubs against the side surface of the fourth guide portion 62. As a result, the roller shaft support portion 46A is sandwiched between the third guide portion 60 and the fourth guide portion 62 via the first auxiliary roller 50A and the second auxiliary roller 52A, and rotation around the arm 40 is fixed. Therefore, if the shaft 34 rotates further from the state shown in schematic diagram 608, the position of the roller 42A is maintained in the first position until the roller 42A reaches the position shown in schematic diagram 502.

[0064] When roller 42A is in the state shown in schematic diagram 502, roller 42B is in the state shown in schematic diagram 608. Therefore, while roller 42A changes from the state shown in schematic diagram 502 to the state shown in schematic diagram 608, in other words, while the posture of roller 42A changes from the first posture to the second posture and then from the second posture to the first posture, the posture of roller 42B is maintained in the first posture. Furthermore, while roller 42A changes from the state shown in schematic diagram 608 to the state shown in schematic diagram 502, the posture of roller 42B changes from the first posture to the second posture and then from the second posture to the first posture.

[0065] As a result, the postures of rollers 42A and 42B alternate between the first posture and the second posture as shaft 34 rotates. In particular, in support section 32 of pallet lifting device 24 provided in ascending section 12, as described above, as shaft 34 rotates, the posture of descending roller 42 changes from the first posture to the second posture and then back to the first posture, and the posture of ascending roller 42 is maintained at the first posture.

[0066] <Pallet transfer using a conveyor> The transfer of pallets 4 between the conveying section 6 and the return section 8 by the pallet lifting device 24 will be described in detail with reference to Fig. 7. Fig. 7 is a side view showing an enlarged process of the conveying section 6, the return section 8, and a portion of the pallet lifting device 24 when the pallet lifting device 24 provided in the ascending section 12 moves the pallet 4 from the return section 8 to the conveying section 6.

[0067] In particular, the side view of each process in Figure 7 is an enlarged view of the adjacent transport unit 6U and return unit 8U and the pallet lifting device 24 viewed in the direction DC shown in the enlarged perspective view 102, in other words, in the direction from one side to the other of two rails 26 described below. In the cross-sectional view of each process in Figure 7, the pallet 4 being transported is shown by a dotted line, and the members further back than the pallet 4 towards the plane of the paper are shown as being see-through through the pallet 4.

[0068] For example, as shown in a process side view 702 of Figure 7, suppose that the return section 8 has transported the pallet 4 to the return unit 8U adjacent to the ascending section 12, in other words, to the end side of the return path 8W. At this point, the pallet lifting device 24 controls the rotation of the shaft 34 so that the longitudinal direction of the arms 40 of each support section 32 is approximately aligned with the up-down direction. In this case, the height of the upper end of roller 42A is approximately aligned with the height of the upper end of roller 28 of transport unit 6U, and the height of the upper end of roller 42B is approximately aligned with the height of the upper end of roller 28 of return unit 8U.

[0069] Therefore, the return unit 8U can transport the pallet 4 from the return unit 8U onto the rollers 42B by sending out the pallet 4 using the friction drive unit 30. As a result, the conveying device 2 moves the pallet 4 from the return section 8 toward the pallet lifting device 24, as shown in the process cross-sectional view 704 in Figure 7.

[0070] As shown in process cross-sectional view 704, at least one set of friction drive units 30 included in the pallet lifting device 24 is positioned so that the drive rollers 30R included therein can laterally grip the pallet 4 sent from the return unit 8U. Therefore, the friction drive units 30 may further drive the pallet 4 sent from the return unit 8U so that the entire pallet 4 leaves the return section 8 and moves to the support parts 32 of the pallet lifting device 24. Alternatively, the friction drive units 30 may stop the rotation of the drive rollers 30R and stop the movement of the pallet 4 so that the pallet 4 sent from the return unit 8U comes to rest on the support parts 32.

[0071] As shown in the process side view 706, the conveying device 2 moves the pallet 4 from the rollers 28 of the return unit 8U onto the rollers 42B of the support section 32, thereby completing the transfer of the pallet 4 from the return section 8 to the pallet lifting device 24.

[0072] Next, the pallet lifting device 24 rotates the shafts 34 of the supports 32, thereby lifting the rollers 42B and the pallet 4 on the rollers 42B, as shown in the process side view 708. While the rollers 42B are lifted, the rollers 42A are lowered, as shown in the process side view 708.

[0073] Here, the posture of the descending roller 42 changes from the first posture to the second posture as the auxiliary roller 48 is guided by the auxiliary roller guide 54 described above. In particular, in the second posture, the roller shaft 44A is oriented perpendicular to the extension direction of the shaft 34 and the roller 42A is positioned above the roller shaft support portion 46A. Therefore, interference between the roller 42A and the pallet 4 is avoided even while the pallet 4 on the roller 42B is rising. In other words, the second posture of the roller 42A is a posture in which the roller 42A retreats from the pallet 4 on the roller 42B.

[0074] As shown in process side view 710, pallet lifting device 24 rotates shafts 34 of each support section 32 until the extension direction of the shafts 34 substantially coincides with the up-down direction. In this case, the height of the upper ends of rollers 42B substantially coincides with the height of the upper ends of rollers 28 of transport unit 6U, and the height of the upper ends of rollers 42A substantially coincides with the height of the upper ends of rollers 28 of return unit 8U. As a result, pallet 4 rises from above rollers 42B until it can be transported onto rollers 28 of transport unit 6U.

[0075] In this embodiment, as shown in the process side view 710, before the ascent of the pallet 4 is completed, another pallet 4 may be transported to the return unit 8U on the ascending section 12 side. The transport of the other pallet 4 in the return unit 8U may be stopped before the ascending section 12 until the ascent of the pallet 4 is completed.

[0076] 7, after the pallet 4 has been lifted, each friction drive unit 30 rotates the drive roller 30R while laterally clamping the pallet 4 on the roller 42B, and sends the pallet 4 onto the roller 28 of the transport unit 6U. As a result, the transport device 2 moves the pallet 4 from the pallet lifting device 24 toward the transport section 6.

[0077] Furthermore, simultaneously with the movement of the pallet 4 from the pallet lifting device 24 to the conveying section 6, each friction drive unit 30 sends another pallet 4 on the rollers 28 of the return unit 8U onto rollers 42A, as shown in process cross-sectional view 712 of Figure 7. As a result, the conveying device 2 moves the pallet 4 from the pallet lifting device 24 toward the conveying section 6, while moving another pallet 4 from the return section 8 toward the pallet lifting device 24. As described above, the conveying device 2 can simultaneously transfer the pallet 4 from the pallet lifting device 24 to the conveying section 6 by the drive roller 30R, and transfer the other pallet 4 from the return section 8 to the pallet lifting device 24 by the other drive roller 30R.

[0078] Thereafter, by executing the above method with rollers 42A and 42B interchanged, pallet lifting device 24 lifts the other pallets 4. Thereafter, by repeatedly executing the same method, conveyance device 2 successively delivers pallets 4 from return section 8 to conveyance section 6 via pallet lifting device 24.

[0079] <Operation of the friction drive unit during pallet transfer> The operation of the friction drive unit 30 provided in the pallet lifting device 24 while the pallet 4 is being transferred from the return section 8 to the conveying section 6 will be described with reference to Fig. 8. Fig. 8 is a schematic side view of each drive roller 30R and each pallet 4, showing the positional relationship between each drive roller 30R of the friction drive unit 30 provided in the pallet lifting device 24 and each pallet 4. In particular, schematic side view 802 is a schematic side view while the transfer of the pallet 4 from the return section 8 to the pallet lifting device 24 and the transfer of the pallet 4 from the pallet lifting device 24 to the conveying section 6 are being performed simultaneously. Furthermore, schematic side view 804 is a schematic side view while the pallet lifting device 24 is raising the pallet 4 on roller 42B.

[0080] As shown in the schematic side view 802, when a pallet 4 is transferred between the conveying section 6 or the return section 8 and the pallet lifting device 24, the friction drive unit 30 of the pallet lifting device 24 causes the drive rollers 30R to clamp each pallet 4 from the side. In other words, the drive rollers 30R provided in the pallet lifting device 24 clamp the pallet 4 from the side while the pallet 4 is being transported. In the above case, in the direction perpendicular to the conveying direction DT of the pallet 4 and the up-and-down direction, the distance from the drive roller 30R on one end side to the drive roller 30R on the other end side is approximately the same as the distance from one end side to the other end side of the pallet 4.

[0081] On the other hand, as shown in the schematic side view 802, when the pallet 4 is raised by the pallet lifting device 24, the friction drive unit 30 of the pallet lifting device 24 retracts the drive roller 30R from the pallet 4. In other words, the drive roller 30R provided in the pallet lifting device 24 is separated from the pallet 4 while the pallet 4 is being raised or lowered, in other words, while the arm 40 is rotating around the shaft 34.

[0082] In particular, the friction drive unit 30 moves the drive roller 30R in a direction away from the pallet 4 in a direction perpendicular to the conveying direction DT and the up-down direction of the pallet 4. In the above case, the distance from the drive roller 30R on one end side to the drive roller 30R on the other end side in the direction perpendicular to the conveying direction DT and the up-down direction of the pallet 4 is longer than the distance from one end side to the other end side of the pallet 4.

[0083] As a result, the friction drive unit 30 provided in the pallet lifting device 24 can transfer the pallet 4 between the conveying section 6 or the return section 8 and the pallet lifting device 24 while reducing interference between the pallet 4 and the drive roller 30R.

[0084] <Coupling of shaft rotation> In this embodiment, the case where the shafts 34 of the support parts 32 all rotate counterclockwise when viewed from the rollers 42 to the shafts 34 has been described, but this is not limiting. For example, the shafts 34 of the support parts 32 may rotate clockwise when viewed from the rollers 42 to the shafts 34.

[0085] Between the multiple support parts 32 included in one pallet lifting device 24, the height of the upper rollers 42 and the height of the lower rollers 42 may be approximately the same, regardless of the rotation of the shafts 34 of each support part 32. This reduces the tilt of the pallet 4 supported by the multiple support parts 32 of the pallet lifting device 24. In particular, the multiple support parts 32 included in one pallet lifting device 24 may have their shafts 34 rotated in tandem, in other words, their arms 40 rotate in tandem.

[0086] An example of a method for interlocking the rotation of the shafts 34 of multiple support parts 32 will be described with reference to Fig. 9. Fig. 9 is a schematic perspective view showing two support parts 32 that are aligned in the conveying direction DT of the pallet 4, selected from the support parts 32 of the pallet lifting device 24.

[0087] The pallet lifting device 24 may further include a belt 72 stretched over the shafts 34 of the two support parts 32 aligned in the conveying direction DT of the pallet 4. The belt 72 may also be stretched over the shafts 34 of the other two support parts 32 that face the two support parts 32 shown in FIG. 9 in a direction perpendicular to the conveying direction DT of the pallet 4 and the up-down direction.

[0088] The belt 72 couples the rotation of the arms 40 between the two support parts 32 by transmitting the rotation of the shaft 34. This allows the pallet lifting device 24 to rotate the arms 40 of both support parts 32 simply by driving the rotation of the shaft 34 of one of the two support parts 32.

[0089] <Additional Notes> As described above, in all of the support parts 32 of the pallet lifting devices 24 provided in the ascending section 12, the position of the rollers 42 that descend as the shafts 34 rotate changes from the first position to the second position and then returns to the first position again. Also, as described above, in all of the support parts 32 of the pallet lifting devices 24 provided in the ascending section 12, the position of the rollers 42 that ascend as the shafts 34 rotate is maintained in the first position.

[0090] In contrast, in each of the support parts 32 of the pallet lifting device 24 provided in the descending section 10, the position of the rollers 42 that rise as the shaft 34 rotates changes from the first position to the second position and then back to the first position. Also, in each of the support parts 32 of the pallet lifting device 24 provided in the descending section 10, the position of the rollers 42 that fall as the shaft 34 rotates is maintained in the first position. This support part 32 may be achieved by appropriately changing the position of each guide part of the auxiliary roller guide 54.

[0091] Therefore, the transfer of the pallet 4 from the conveying section 6 to the return section 8 by the pallet lifting device 24 provided in the lowering section 10 is also achieved in a manner similar to that described above. For example, the conveying device 2 moves the pallet 4 from the conveying section 6 to the pallet lifting device 24, lowers the pallet 4 by the pallet lifting device 24, and moves the pallet 4 from the pallet lifting device 24 to the return section 8, thereby transferring the pallet 4 from the conveying section 6 to the return section 8.

[0092] As described above, the conveying device 2 circulates the pallets 4 by transferring the pallets 4 in the order of the conveying section 6, the descending section 10, the returning section 8, and the ascending section 12. The conveying device 2 circulates the multiple pallets 4 and sequentially conveys the multiple vehicle bodies X by placing a vehicle body X on each of the multiple pallets 4 located in the conveying section 6.

[0093] In this embodiment, the shaft 34 and arm 40 of the support unit 32 of the pallet lifting device 24 both rotate in one direction, but this is not limited thereto, and the shaft drive unit 38 may be capable of reversing the rotation direction of the shaft 34. For example, the support unit 32 may raise and lower the pallet 4 by repeatedly rotating the arm 40 halfway in one direction and then halfway in the opposite direction from a state in which the arm 40 extends in the vertical direction. In this case, the rotation of the roller shaft support unit 46 around the arm 40 may be achieved by another drive unit such as a motor, and the support unit 32 may appropriately change the position of each roller 42 between a first position and a second position.

[0094] [Embodiment 2] <Flexible roller> Other embodiments of the present disclosure will be described below. For ease of explanation, in the following embodiments, components having the same functions as those described in the previous embodiment will be denoted by the same reference numerals, and their descriptions will not be repeated.

[0095] The transport device 2 according to this embodiment has the same configuration as the transport device 2 according to the previous embodiment, except that the pallet lifting device 24 has a support part 74 instead of the support part 32. The support part 74 according to this embodiment will be described with reference to Fig. 10. Fig. 10 is an enlarged perspective view of the support part 74.

[0096] Compared to the support part 32 of the previous embodiment, the support part 74 of this embodiment has a roller 76, a roller shaft 78, and a roller shaft support part 80 instead of the roller 42, the roller shaft 44, and the roller shaft support part 46, respectively.

[0097] Rollers 76 are formed on both ends of arm 40, and revolve around shaft 34 as shaft 34 rotates. Roller shafts 78 are formed on roller shaft support parts 80, and rollers 76 rotate around roller shafts 78. In this embodiment, roller shaft support parts 80 are fixed to arm 40. For this reason, roller shafts 78 always extend in a direction substantially parallel to the extension direction of shaft 34 unless an external force, which will be described later, is applied to rollers 76 and roller shafts 78.

[0098] The rollers 76 and roller shafts 78 according to this embodiment are both flexible and elastic. In particular, when a force perpendicular to the extension direction of the shaft 34 is applied to the rollers 76 and roller shafts 78, they bend from a state in which they extend substantially parallel to the extension direction of the shaft 34 to an axis on the side of the roller shaft support portion 80. Meanwhile, when the force is released, the rollers 76 and roller shafts 78 return to a state in which they extend substantially parallel to the extension direction of the shaft 34. The rollers 76 and roller shafts 78 do not need to be restored to a state in which they extend completely parallel to the extension direction of the shaft 34; they only need to be restored to a degree that does not interfere with the rotation of the rollers 76 around the roller shafts 78. The rollers 76 and roller shafts 78 may have a longer axial length than the rollers 42 and roller shafts 44.

[0099] The support unit 74 has, for example, two rollers 76, namely, roller 76A that rotates about roller shaft 78A and roller 76B that rotates about roller shaft 78B. In particular, Fig. 10 shows the support unit 74 in a state in which roller 76A is located at the upper end of the arm 40 and roller 76B is located at the lower end of the arm 40. The support unit 74 also has, as two roller shaft support units 80, roller shaft support unit 80A where roller shaft 78A is formed and roller shaft support unit 80B where roller shaft 78B is formed.

[0100] Except for the above points, the support section 74 according to this embodiment has the same configuration as the support section 32 according to the previous embodiment. Therefore, also in the pallet lifting device 24 according to this embodiment, the rollers 76 of the support section 74 can take the first position for supporting the pallet 4.

[0101] The raising and lowering of a pallet 4 by the pallet lifting device 24 according to this embodiment will be described with reference to Fig. 11. Fig. 11 is an enlarged side view of one of the support portions 74 and a portion of the pallet 4 in a state in which the pallet 4 is supported and raised and lowered by the pallet lifting device 24. In particular, Fig. 11 is a view showing one of the support portions 74 and a portion of the pallet 4 as viewed in the return direction DR.

[0102] In this embodiment, the transport of the pallet 4 from the conveying section 6 or the return section 8 to the pallet lifting device 24 is achieved by the same method as in the previous embodiment. In particular, the enlarged side view 1102 in Figure 11 shows a state in which the pallet 4 has been transported from onto roller 28 of the return section 8 to onto roller 76B of the support section 74, with the extension direction of the arm 40 being the vertical direction and roller 76B being below roller 76A.

[0103] In this embodiment, the rollers 76 and roller shafts 78 may have flexibility as described above, but may also have a degree of rigidity that prevents them from bending under a force equivalent to the weight of the pallet 4. For example, the rollers 76 and roller shafts 78 may have a degree of rigidity that allows them to support the pallet 4 without any problems when the pallet 4 is loaded on the rollers 76.

[0104] With a pallet 4 loaded on roller 76B located below roller 76A, when shaft 34 and arm 40 rotate, the pallet 4 and roller 76B rise, and roller 76A descends. As shaft 34 and arm 40 continue to rotate, roller 76A comes into contact with the pallet 4 on roller 76B.

[0105] As a result, roller 76A is pushed up by pallet 4 on roller 76B on the side opposite arm 40. As a result, as shown in enlarged side view 1104, roller 76A is bent upward together with roller shaft 78A.

[0106] As the shaft 34 and the arm 40 continue to rotate, the rollers 76A and 76B are released from contact with the pallet 4. As a result, the rollers 76A and the roller shafts 78A are restored to the first position in which they extend in substantially the same direction as the extension direction of the shaft 34, as shown in enlarged side view 1106.

[0107] In this embodiment, when the pallet 4 is raised or lowered, the shaft 34 and the arm 40 rotate until the arm 40 extends vertically and the roller 76B is positioned above the roller 76A. This completes the lifting of the pallet 4 on the roller 76B, as shown in the enlarged side view 1106. In this embodiment, the transport of the pallet 4 from the pallet lifting device 24 to the conveying section 6 or the return section 8 is achieved in the same manner as in the previous embodiment. In particular, as shown in the enlarged side view 1106 of FIG. 11, the pallet 4 on the roller 76B that has been raised is transported from the roller 76B of the support section 74 to the roller 28 of the conveying section 6.

[0108] As shown in enlarged side view 1106, when the lifting of pallet 4 on rollers 76B is completed, rollers 76A are restored to the first position. Therefore, the conveying device 2 according to this embodiment can convey another pallet 4 on rollers 28 of the return section 8 to rollers 76A of the support section 74 at this point. In other words, the conveying device 2 according to this embodiment can simultaneously convey a pallet 4 from the pallet lifting device 24 to the conveying section 6 and another pallet 4 from the return section 8 to the pallet lifting device 24.

[0109] In this embodiment, the transfer of pallets 4 from the conveying section 6 to the returning section 8 by the pallet lifting device 24 provided in the descending section 10 is also achieved in the same manner as described above. As described above, the conveying device 2 according to this embodiment circulates the pallets 4 by transferring the pallets 4 in the order of the conveying section 6, the descending section 10, the returning section 8, and the ascending section 12.

[0110] [Embodiment 3] <Rollers that go around the pallet> A further embodiment of the present disclosure will now be described with reference to Fig. 12. Fig. 12 shows an enlarged perspective view 1202 of a portion of the transport device 2 and an enlarged perspective view 1204 of a support section 82, which is part of the pallet lifting device 24 and will be described later.

[0111] As shown in an enlarged perspective view 1202, the conveying device 2 according to this embodiment is different from the conveying device 2 according to the first embodiment in that the pallet lifting device 24 includes a support part 82 instead of the support part 32. Furthermore, the pallet lifting device 24 according to this embodiment includes the support part 82 closer to the end in the conveying direction DT than the friction drive unit 30. Except for the above, the conveying device 2 according to this embodiment has the same configuration as the conveying device 2 according to the first embodiment.

[0112] As shown in enlarged perspective view 1204, the support unit 82 according to this embodiment has the same configuration as the support unit 32 according to the first embodiment, except that it includes the roller shaft support unit 80 according to the previous embodiment instead of the roller shaft support unit 46. In other words, the support unit 82 according to this embodiment has the same configuration as the support unit 32 according to the first embodiment, except that the roller 42 is always in the first position regardless of the rotation of the arm 40 around the shaft 34.

[0113] Note that the support unit 82 has, for example, two rollers 42, roller 42A that rotates around roller shaft 44A and roller 42B that rotates around roller shaft 44B. In particular, the enlarged perspective view 1204 shows the support unit 82 in a state in which roller 42A is located at the upper end of the arm 40 and roller 42B is located at the lower end of the arm 40. The support unit 82 also has, as two roller shaft support units 80, roller shaft support unit 80A where roller shaft 44A is formed and roller shaft support unit 80B where roller shaft 44B is formed.

[0114] The raising and lowering of the pallet 4 by the pallet lifting device 24 according to this embodiment will be described with reference to Fig. 13. Fig. 13 is an enlarged side view of a part of the pallet lifting device 24 and the pallet 4 in a state in which the pallet 4 is supported and raised and lowered by the pallet lifting device 24.

[0115] In particular, Figure 13 shows two support members 74 of the pallet lifting device 24 as viewed in a direction perpendicular to the conveying direction DT and the up-down direction. In Figure 13, the pallet 4 is shown with a dotted line, and the members further back than the pallet 4 are shown as transparent. In order to clearly illustrate the entire pallet 4, the scale of the pallet 4 in Figure 13 in the conveying direction DT has been reduced so that the entire pallet 4 fits within each view of Figure 13.

[0116] In this embodiment, the transport of the pallet 4 from the conveying section 6 or the return section 8 to the pallet lifting device 24 is achieved by the same method as in each of the previously described embodiments. In particular, the enlarged side view 1302 in Figure 13 shows a state in which the pallet 4 has been transported from onto roller 28 of the return section 8 to onto roller 42B of the support section 82, with the extension direction of the arm 40 being the vertical direction and roller 42B being below roller 42A.

[0117] As described above, the pallet lifting device 24 according to this embodiment has the support parts 82 located closer to the end in the conveying direction DT than the friction drive unit 30. Therefore, each support part 82 of the pallet lifting device 24 according to this embodiment supports the pallet 4 by supporting the end of the pallet 4 in the conveying direction DT with the rollers 42B.

[0118] When the shaft 34 and the arm 40 rotate with the pallet 4 loaded on the roller 42B located below the roller 42A, the pallet 4 and the roller 42B rise, and the roller 42A falls. Here, in this embodiment, as shown in the enlarged side view 1304, the arm 40 of each support unit 82 rotates so that the roller 42B supporting the pallet 4 moves toward the center of the pallet 4 in the conveying direction DT. For example, as shown in the enlarged side view 1304, the arm 40 of the support unit 82 on the left side as viewed in the drawing rotates counterclockwise, while the arm 40 of the support unit 82 on the right side as viewed in the drawing rotates clockwise.

[0119] As a result, in this embodiment, as shown in enlarged side view 1304, the rollers 42A of each support portion 82 descend while passing further to the periphery than the end of the pallet 4 in the conveying direction DT. As a result, the rollers 42A of each support portion 82 move around the pallet 4 and descend while maintaining the first posture.

[0120] In this embodiment, when the pallet 4 is raised or lowered, the shaft 34 and the arm 40 rotate until the arm 40 extends vertically and the roller 42B is positioned above the roller 42A. This completes the lifting of the pallet 4 on the roller 42B, as shown in the enlarged side view 1306. In this embodiment, the transport of the pallet 4 from the pallet lifting device 24 to the conveying section 6 or the return section 8 is achieved by the same method as in the previous embodiments. In particular, as shown in the enlarged side view 1306 of FIG. 13, the pallet 4 on the roller 42B that has been raised is transported from the roller 42B of the support section 82 to the roller 28 of the conveying section 6.

[0121] 13, regardless of the rotation of the arm 40, the position of the rollers 42A is in the first position. Therefore, the conveying device 2 according to this embodiment can convey another pallet 4 on the rollers 28 of the return section 8 onto the rollers 42A at the point when the lifting of the pallet 4 on the rollers 42B of the support section 82 is completed. In other words, the conveying device 2 according to this embodiment can simultaneously convey a pallet 4 from the pallet lifting device 24 to the conveying section 6 and another pallet 4 from the return section 8 to the pallet lifting device 24.

[0122] In this embodiment, the transfer of pallets 4 from the conveying section 6 to the returning section 8 by the pallet lifting device 24 provided in the descending section 10 is also achieved in the same manner as described above. As described above, the conveying device 2 according to this embodiment circulates the pallets 4 by transferring the pallets 4 in the order of the conveying section 6, the descending section 10, the returning section 8, and the ascending section 12.

[0123] <Summary> (1) A pallet lifting device according to aspect 1 of the present disclosure is a pallet lifting device that raises or lowers a pallet fed at a first height to a second height before feeding it out, and includes a plurality of support parts for supporting and raising or lowering the pallet, each of which has an arm extending in a direction perpendicular to a first axis, which is a horizontal axis, and which rotates around the first axis located in the center of the arm's longitudinal direction, and a pair of rollers provided at both ends of the arm, and each of the rollers is configured so that the roller axis is perpendicular to a second axis along the longitudinal direction of the arm and the roller axis is parallel to the first axis, and the roller can assume a first position for supporting the pallet.

[0124] With the above configuration, the pallet lifting mechanism can unload a pallet from one roller and load another pallet onto the other roller by placing both of a pair of rollers in the first position. Therefore, the pallet lifting device can unload a pallet and load another pallet without requiring time to load another pallet after unloading the lifted pallet, and can then move on to lifting or lowering the other pallet. Therefore, the pallet lifting device can lift and lower multiple pallets in a shorter time.

[0125] (2) In the pallet lifting device according to aspect 2 of the present disclosure, in aspect 1 above, the roller shaft of each of the rollers is rotatable around the second shaft, and is configured so that the roller shaft rotates around the second shaft from the first position and the roller can assume a second position in which it retreats from the pallet.

[0126] With the above configuration, even when the pallet is loaded on one of the rollers and the arm is rotated to raise or lower the pallet, the pallet lifting mechanism can reduce interference between the other roller and the pallet by switching the position of the other roller to the second position, which enables the pallet lifting mechanism to efficiently raise and lower the pallet regardless of the position of the support part relative to the pallet being raised or lowered.

[0127] (3) In a pallet lifting device according to aspect 3 of the present disclosure, in aspect 2 above, each of the support parts has an auxiliary roller that revolves around the second axis in conjunction with the roller axis of each of the rollers, and an auxiliary roller guide that guides the auxiliary roller and alternately changes the position of the roller between the first position and the second position as the arm rotates.

[0128] With the above configuration, the pallet lifting mechanism can switch the roller position between the first position and the second position simply by rotating the arm. Therefore, the pallet lifting device does not need to be equipped with a separate drive unit for changing the roller position, and the support unit can be realized with a simpler configuration.

[0129] (4) In a pallet lifting device according to a fourth aspect of the present disclosure, in the second or third aspect, the roller in the second position is positioned higher on the opposite side than on the arm side.

[0130] With the above configuration, the pallet lifting mechanism can reduce the likelihood of the roller being positioned lower than the lower end of the arm when the roller is in the second position. Therefore, the pallet lifting device can reduce interference between the ground and the roller even when the support portion is positioned lower from the ground. By lowering the support portion from the ground, the pallet lifting device can reduce the overall height of the device; in other words, the height at which the pallet is brought in and the height at which the pallet is taken out are reduced.

[0131] Reducing the height of the pallet lifting device leads to a lower height at which pallets are transported in a transport device equipped with the pallet lifting device. When a transport device transports a pallet loaded with an object such as a vehicle body, and a worker transfers onto the transported pallet to work on the object, lowering the height at which the pallet is transported reduces the burden on the worker getting on and off the pallet.

[0132] (5) In the pallet lifting device according to aspect 5 of the present disclosure, in aspect 1 above, while the arm rotates around the first axis with the pallet loaded on one of the pair of rollers formed on the arm, the other of the pair of rollers bends as it comes into contact with the pallet and then returns to its original position as it is released from contact with the pallet.

[0133] With the above configuration, even if the pallet comes into contact with the rollers, the pallet lifting mechanism deforms the rollers to avoid the pallet, and then returns to its original shape when the contact with the pallet is released, allowing another pallet to be carried onto the rollers. Therefore, the pallet lifting device does not require a mechanism for rotating the rollers around the arms, and can efficiently lift and lower pallets regardless of the position of the support part relative to the pallet being lifted or lowered.

[0134] (6) In a pallet lifting device according to aspect 6 of the present disclosure, in aspect 1 above, each of the rollers is in the first position regardless of the rotation of the arm around the first axis, and while the arm rotates around the first axis with the pallet loaded on one of the pair of rollers formed on the arm, the other of the pair of rollers moves around the pallet.

[0135] With the above configuration, the pallet lifting mechanism can lift and lower the pallet while causing the rollers to avoid the pallet, while keeping the rollers in the first position. Therefore, the pallet lifting device does not require a mechanism for rotating the rollers around the arms, and can efficiently lift and lower the pallet while suppressing a decrease in the rigidity of the rollers.

[0136] (7) In a pallet lifting device according to aspect 7 of the present disclosure, in any of aspects 1 to 6 above, the device is provided with a first drive roller that transports the pallet at the first height and a second drive roller that transports the pallet at the second height.

[0137] With the above-described configuration, the pallet lifting mechanism enables the pallet to be transported by the drive rollers and removed, and also enables the pallet being removed to be stopped at a specified position.

[0138] (8) In the pallet lifting device according to aspect 8 of the present disclosure, in the above-mentioned aspect 7, it is provided with a first drive roller that transports the pallet at the first height and a second drive roller that transports the pallet at the second height.

[0139] With the above configuration, the pallet lifting mechanism can more efficiently carry out the removal of a pallet and carry in another pallet at the same time, and can lift and lower multiple pallets in a shorter time.

[0140] (9) In a pallet lifting device according to aspect 9 of the present disclosure, in aspect 7 or 8 above, the first drive roller and the second drive roller each clamp the pallet from the side while the pallet is being transported, while moving away from the pallet while the arm rotates around the first axis.

[0141] With the above-described configuration, the pallet lifting mechanism can reduce interference between the pallet and the drive roller.

[0142] (10) In a pallet lifting device according to a tenth aspect of the present disclosure, in any one of the seventh to ninth aspects, at least one of the rollers is a driven roller.

[0143] With the above-described configuration, the pallet lifting mechanism can transport the pallet while reducing the number of drive units for rotating the rollers.

[0144] (11) In a pallet lifting device according to an eleventh aspect of the present disclosure, in any one of the first to tenth aspects, each of the arms rotates in only one direction around the first axis.

[0145] With the above-described configuration, the pallet lifting mechanism does not require a mechanism for switching the rotation direction of the arm, and the support section can be realized with a simpler configuration.

[0146] (12) In a pallet lifting device according to aspect 12 of the present disclosure, in any of aspects 1 to 11 above, each of the support parts has a shaft formed in the longitudinal center of the arm and extending along the first axis, and is equipped with a belt that is stretched between the shafts of the multiple support parts and links the rotation of the multiple arms.

[0147] With the above-described configuration, the pallet lifting mechanism can reduce the number of drive units that rotate the arms, while enabling the rotation of the arms to be linked among a plurality of support units.

[0148] (13) A conveying device according to aspect 13 of the present disclosure is a conveying device comprising: a conveying section that conveys a pallet in a conveying direction along a conveying path located at the first height; a return section that conveys the pallet in a direction opposite to the conveying direction along a return path located below the conveying path and at the second height; a descending section that transfers the pallet from the conveying path to the return path; and an ascending section that transfers the pallet from the return path to the conveying path, wherein at least one of the descending section and the ascending section is equipped with a pallet lifting device according to any one of aspects 1 to 12 above.

[0149] With the above configuration, the conveying device can circulate multiple pallets in a shorter time, thereby reducing the time required to convey multiple objects.

[0150] (14) A conveying device according to a fourteenth aspect of the present disclosure is the thirteenth aspect, wherein both the descending section and the ascending section are provided with the pallet lifting device.

[0151] With the above configuration, the conveying device can circulate multiple pallets in an even shorter time, further reducing the time required to convey multiple objects.

[0152] The present disclosure 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 disclosure. [Explanation of symbols]

[0153] 2. Conveyor equipment 4 palettes 6. Conveyor 8 Return Department 10 Descending part 12 Ascending section 24 Pallet lifting device 30R drive roller 32 Support part 34 Shaft 40 Arm 42 Laura 44 Roller shaft 48 Auxiliary roller 54 Auxiliary roller guide 72 Belt

Claims

1. A pallet lifting device that raises or lowers a pallet fed at a first height to a second height and then feeds the pallet out, a plurality of support parts for supporting and elevating the pallet; Each of the support portions is an arm extending in a direction perpendicular to a first axis, which is a horizontal axis, and rotating around the first axis located at the center of the arm in its longitudinal direction; a pair of rollers provided at both ends of the arm; Each of the rollers is The roller axis is perpendicular to the second axis along the longitudinal direction of the arm, A pallet lifting device, wherein the rollers are configured to be able to take a first position for supporting the pallet, with the roller axes being parallel to the first axis.

2. Each of the rollers is The roller shaft is rotatable around the second shaft, 2. The pallet lifting device according to claim 1, wherein the device is configured to be capable of assuming a second position in which the roller shaft rotates around the second shaft from the first position and the roller retreats from the pallet.

3. Each of the support portions is 3. A pallet lifting device as described in claim 2, further comprising: an auxiliary roller that revolves around the second axis in conjunction with the roller axis of each of the rollers; and an auxiliary roller guide that guides the auxiliary roller and alternately changes the position of the roller between the first position and the second position as the arm rotates.

4. 3. The pallet lifting device according to claim 2, wherein the roller in the second position is positioned higher on the opposite side than on the arm side.

5. A pallet lifting device as described in claim 1, wherein while the arm rotates around the first axis with the pallet loaded on one of the pair of rollers formed on the arm, the other of the pair of rollers bends as it comes into contact with the pallet and returns to its original position as it is released from contact with the pallet.

6. each of the rollers is in the first position regardless of rotation of the arm about the first axis; A pallet lifting device as described in claim 1, wherein while the arm rotates around the first axis with the pallet loaded on one of the pair of rollers formed on the arm, the other of the pair of rollers moves around the pallet.

7. 7. A pallet lifting device according to claim 1, comprising a first drive roller that transports the pallet at the first height, and a second drive roller that transports the pallet at the second height.

8. 8. A pallet lifting device according to claim 7, wherein the conveyance of the pallet by the first drive roller and the conveyance of another pallet by the second drive roller can be carried out simultaneously.

9. 8. The pallet lifting device according to claim 7, wherein each of the first drive roller and the second drive roller laterally holds the pallet while the pallet is being transported, but moves away from the pallet while the arm rotates about the first axis.

10. 8. A pallet lifting apparatus according to claim 7, wherein at least one of said rollers is a driven roller.

11. 7. A pallet lifting device according to claim 1, wherein each of said arms rotates in only one direction about said first axis.

12. Each of the support portions has a shaft formed at the center of the arm in the longitudinal direction and extending along the first axis, 7. A pallet lifting device according to claim 1, further comprising a belt that is stretched between the shafts of the plurality of support parts and links the rotation of the plurality of arms.

13. a conveying unit that conveys a pallet in a conveying direction along a conveying path located at the first height; a return unit that transports the pallet in a direction opposite to the transport direction along a return path located below the transport path and at the second height; a descending section that transfers the pallet from the conveying path to the return path; a lifting section that transfers the pallet from the return path to the conveying path, A conveying device, wherein at least one of the descending section and the ascending section is provided with the pallet lifting device according to any one of claims 1 to 6.

14. 14. The conveying apparatus of claim 13, wherein both the descending section and the ascending section are provided with the pallet lifting device.

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