JP7737320B2 - Pallet lifting mechanism, multi-story parking device, and pallet lifting method - Google Patents

Description

The present invention relates to a pallet lifting mechanism, a multi-story parking system equipped with the same, and a pallet lifting method.

The lifting pallets that move up and down in a multi-story parking system are raised and lowered by a pallet lifting mechanism 100, such as the one shown in Figure 6. This pallet lifting mechanism 100 raises and lowers the lifting pallet by winding and unwinding four wire ropes that suspend the lifting pallet, and is equipped with a drum shaft 110 and a motor 120 installed on the beam 130 of the multi-story parking system. The drum shaft 110 includes two drums 112, 114, a connecting shaft 116 that coaxially connects them, and a sprocket 118, with a chain 122 wound around the sprocket 118.

The rotational force generated by the motor 120 is transmitted to the drum shaft 110 via the chain 122 and sprocket 118, causing the two drums 112, 114 to wind and unwind the four wire ropes. Patent Document 1 discloses the drum structure used in such a pallet lifting mechanism. Note that reference symbol D5 in Figure 6 indicates the drum diameter of the drum 114, and reference symbol S5 indicates the sprocket diameter of the sprocket 118. Reference symbol C5 indicates the distance from the lateral center of the pallet lifting mechanism 100 (equivalent to the lateral center of the beam 130) to the lateral center of the wire rope winding portion of the drum 114, and reference symbol L5 indicates the required length in the depth direction (left-right direction in Figure 6(b)).

Patent No. 6512678

6, which uses wire ropes to suspend the lifting pallet, has the problem of requiring more space than a chain-type pallet lifting mechanism that uses chains to suspend the lifting pallet. In particular, the required length L5 in the depth direction is also larger due to the use of a sprocket 118 with a sprocket diameter S5 large enough to obtain a large reduction ratio regardless of the drum diameter D5 in order to ensure the necessary torque.
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to reduce the space required for a pallet lifting mechanism.

(Aspects of the invention)
The following embodiments of the present invention are examples of the configuration of the present invention and are described in terms to facilitate understanding of the various configurations of the present invention. Each term does not limit the technical scope of the present invention. Therefore, while taking into consideration the best mode for carrying out the invention, some of the components of each term may be replaced or deleted, or other components may be added, and these may also be included in the technical scope of the present invention.

(1) A pallet lifting mechanism for a multi-story parking system equipped with multiple pallets for accommodating vehicles, which lifts and lowers at least each of the lifting pallets that move up and down via four wire ropes suspending the lifting pallet, including a first drum for winding and unwinding two of the four wire ropes suspending one side of the lifting pallet in the lateral direction corresponding to the width of the vehicle, a second drum for winding and unwinding two of the four wire ropes suspending the other side of the lifting pallet in the lateral direction, a motor for generating rotational force, and a drive shaft for transmitting the rotational force, wherein a drive sprocket is provided for the drive shaft for receiving the rotational force from the motor, and a drum sprocket is provided for each of the first drum and the second drum for receiving the rotational force from the drive shaft.

The pallet lifting mechanism described in this section lifts and lowers a lifting pallet via four wire ropes and includes a first drum, a second drum, a motor, and a drive shaft. The first drum winds and unwinds two of the four wire ropes, and these two wire ropes suspend one side of the lifting pallet in the lateral direction corresponding to the width direction of the vehicle. In contrast, the second drum winds and unwinds the remaining two of the four wire ropes, and these two wire ropes suspend the other side of the lifting pallet in the lateral direction. The motor generates a rotational force to rotate the first and second drums.

The drive shaft transmits the rotational force generated by the motor to the first and second drums, and is provided with a drive sprocket for receiving the rotational force from the motor. Furthermore, each of the first and second drums is provided with a drum sprocket for receiving the rotational force from the drive shaft. Therefore, the rotational force generated by the motor is transmitted to the drive shaft via the drive sprocket provided on the drive shaft, and is further transmitted from the drive shaft to the first and second drums via the drum sprockets provided on the first and second drums. In other words, the rotational force is transmitted separately from the motor to the first drum and from the motor to the second drum via the drive shaft.

Compared to conventional structures in which rotational force is transmitted from a motor to a drum shaft connected to two drums, this reduces the torque required to rotate each of the first and second drums by half, allowing for a smaller sprocket diameter for the drum sprockets provided on the first and second drums. Additionally, the adoption of a two-stage reduction structure via the drive shaft reduces the required reduction ratio of the motor, allowing for a more compact motor gear case. These features result in a space-saving design for the entire pallet lifting mechanism, and the resulting space can be used for a variety of purposes. Furthermore, the smaller motor gear case allows for the use of a geared motor with a brake, similar to that used in chain-type pallet lifting mechanisms, allowing for the sharing of components.

Furthermore, because the first and second drums are supported individually, the required precision for shaft center wobble is relaxed compared to conventional structures in which both ends of the drum shaft to which the two drums are connected are supported. Furthermore, because the connecting shaft that previously connected the two drums is no longer necessary, the welding required for such a connection is also no longer necessary, reducing the manufacturing and component costs of the individual drums. Furthermore, because the elimination of the connecting shaft that previously connected the two drums simplifies the drum structure, for example, even if the lateral size of the lifting pallet changes, the first and second drums can be flexibly adjusted by adjusting their installation positions without requiring design changes to the drums themselves.

(2) A pallet lifting mechanism according to the above item (1), wherein the drum diameters of the first drum and the second drum and the sprocket diameter of the drum sprocket are the same or approximately the same.
In the pallet lifting mechanism described in this section, the drum diameters of the first and second drums and the sprocket diameters of the drum sprockets provided thereon are the same or approximately the same. Therefore, as described in section (1) above, if the sprocket diameter of the drum sprockets is made smaller than conventional, the drum diameters of the first and second drums and the sprocket diameter of the drum sprockets are set to, for example, approximately the same as the drum diameter of conventional drums. The space thus secured can then be used for any purpose.

Here, at least a portion of the space obtained as described above may be used to increase the drum diameter of the first and second drums. That is, the drum diameter of the first and second drums is made larger than that of conventional drums, and the sprocket diameter of the drum sprockets provided thereon is adjusted to match the drum diameter. This increases the amount of wire rope taken up compared to conventional drums without changing the lateral size or installation space of the first and second drums, thereby increasing the lifting stroke of the first and second drums. This allows for the lifting and lowering of lifting pallets located higher than conventional drums, meeting the needs for taller multi-story parking systems. Note that as the drum diameter of the first and second drums increases, the required torque also increases accordingly; however, because a two-stage reduction mechanism via the drive shaft is used, there are no problems with generating the required torque.

(3) In the above items (1) and (2), a pallet lifting mechanism including a first support member that pivotally supports one side of the first drum, a second support member that pivotally supports the other side of the first drum and one side of the drive shaft, a third support member that pivotally supports the one side of the second drum and the other side of the drive shaft, and a fourth support member that pivotally supports the other side of the second drum.
The pallet lifting mechanism described in this section further includes a first support member, a second support member, a third support member, and a fourth support member, wherein the first support member pivotally supports one lateral side of the first drum, the second support member pivotally supports the other lateral side of the first drum and one lateral side of the drive shaft, the third support member pivotally supports the other lateral side of the drive shaft and one lateral side of the second drum, and the fourth support member pivotally supports the other lateral side of the second drum.

As a result, the first drum, drive shaft, and second drum are arranged from one side to the other in the order described above. The first drum has a drum sprocket on its other side, adjacent to one side of the drive shaft in the lateral direction, and the second drum has a drum sprocket on its one side, adjacent to the other side of the drive shaft in the lateral direction. This structure ensures that the first drum and second drum are positioned in appropriate lateral positions for winding up the four wire ropes, while ensuring that rotational force is transmitted to them from the motor via the drive shaft.

(4) In the above (3), the first drum and the second drum are supported by the first support member, the second support member, the third support member, and the fourth support member via sliding bearings.
In the pallet lifting mechanism described in this section, the first drum and the second drum are journaled to the first to fourth support members via slide bearings. By journaling with such a simple structure, the number and size of components used can be reduced, and the first drum and the second drum can be positioned as far outward as possible in the lateral direction while maintaining the same lateral installation range as conventional drums. In other words, the first drum can be positioned as far to one side as possible in the lateral direction, and the second drum can be positioned as far to the other side as possible in the lateral direction.

If the newly gained space in the lateral direction is used to expand the lateral size of the first and second drums, the amount of wire rope wound by the first and second drums will increase, thereby increasing the lifting stroke. Alternatively, by shifting the first and second drums outward in the lateral direction, the suspension position of the lifting pallet by the four wire ropes will also shift outward, thereby increasing the width of the vehicle that can be accommodated on the lifting pallet. Furthermore, the use of self-lubricating resin sliding bearings makes handling easier.

(5) In the above items (3) and (4), the second support member and the third support member support the drive shaft above the first drum and the second drum when viewed from the side, and the motor is a pallet lifting mechanism installed below the drive shaft between the second support member and the third support member.
In the pallet lifting mechanism described in this section, the second support member and the third support member support the drive shaft above the first drum and the second drum when viewed from the side. Therefore, a chain is wound around the vicinity of one lateral end of the drive shaft and the drum sprocket of the first drum located below, and torque is transmitted from the drive shaft to the first drum via this chain. Similarly, a chain is wound around the vicinity of the other lateral end of the drive shaft and the drum sprocket of the second drum located below, and torque is transmitted from the drive shaft to the second drum via this chain.

In addition, since the motor is installed below the drive shaft between the second and third support members, a chain is looped around the motor's rotating shaft and the drive sprocket of the drive shaft located above it, and rotational force is transmitted from the motor to the drive shaft via this chain. This arrangement consolidates the positions of the components in the depth direction, which is perpendicular to the lateral direction in a plan view, thereby saving space particularly in the depth direction. Furthermore, by installing the motor below the drive shaft, the motor can be installed in a lower position than before, simplifying the structure of the motor's base.

(6) In the above items (3) and (4), the second support member and the third support member are fixed to a beam extending in the lateral direction, and support the first drum and the second drum above the beam when viewed in the lateral direction, and support the drive shaft below the beam, and the motor is a pallet lifting mechanism installed above the beam between the second support member and the third support member.
In the pallet lifting mechanism described in this section, the second support member and the third support member are fixed to a beam extending in the lateral direction and pivotally support each member. That is, when viewed in the lateral direction, the second support member and the third support member pivotally support the first drum and the second drum above the beam and pivotally support the drive shaft below the beam, thereby arranging the beam between the first drum and the second drum and the drive shaft in the height direction.

For this reason, a chain is looped around the vicinity of one lateral end of the drive shaft and the drum sprocket of the first drum located above it, sandwiching the beam, and rotational force is transmitted from the drive shaft to the first drum via this chain. Similarly, a chain is looped around the vicinity of the other lateral end of the drive shaft and the drum sprocket of the second drum located above it, sandwiching the beam, and rotational force is transmitted from the drive shaft to the second drum via this chain. In addition, the motor is installed above the beam between the second and third support members, resulting in a beam being positioned between the motor and drive shaft in the height direction. For this reason, a chain is looped around the motor's rotating shaft and the drive sprocket of the drive shaft located below it, sandwiching the beam, and rotational force is transmitted from the motor to the drive shaft via this chain.

This arrangement consolidates the positions of each component in the depth direction, which is perpendicular to the lateral direction in a plan view, thereby saving space particularly in the depth direction. Furthermore, by locating the drive shaft below the beam, the space below the beam is effectively utilized while minimizing the height-wise space required for components installed above the beam. Furthermore, by installing the first and second drums as high as possible within the limited installation space, the wire rope is unwound from a higher position, thereby increasing the lifting pallet's suspension position. Furthermore, by placing beams between the first and second drums and the drive shaft, and between the motor and the drive shaft, the height-wise distance between the drum sprocket and the drive shaft and the height-wise distance between the motor's rotating shaft and the drive sprocket of the drive shaft are increased. This increases the length of the chain wound around them, stabilizing the chain drive.

(7) A multi-story parking system including a plurality of pallets for accommodating vehicles, and equipped with a pallet lifting mechanism described in any one of (1) to (6) above for at least each of the lifting pallets that move up and down.
The multi-story parking system described in this paragraph includes a plurality of pallets for accommodating vehicles, and is provided with a pallet lifting mechanism described in any one of paragraphs (1) to (6) above for each of the lifting pallets that move up and down among the plurality of pallets. This provides the same effect as the pallet lifting mechanisms described in paragraphs (1) to (6) above, thereby improving the added value of the multi-story parking system.

(8) A pallet lifting method for a multi-story parking system equipped with multiple pallets for accommodating vehicles, in which at least each of the lifting pallets that moves up and down is lifted and lowered via four wire ropes suspending the lifting pallet, comprising: a first drum, a second drum, a motor, and a drive shaft; the first drum winds and unwinds two of the four wire ropes suspending one side of the lifting pallet in the lateral direction corresponding to the width direction of the vehicle; the second drum winds and unwinds two of the four wire ropes suspending the other side of the lifting pallet in the lateral direction; a drive sprocket provided on the drive shaft receives the rotational force generated by the motor; and drum sprockets provided on each of the first and second drums receive the rotational force from the drive shaft.

(9) A pallet lifting method according to the above item (8), wherein the drum diameters of the first drum and the second drum and the sprocket diameter of the drum sprocket are made the same or approximately the same.
(10) In the above items (8) and (9), a pallet lifting method is provided in which the one side of the first drum is supported by a first support member, the other side of the first drum and the one side of the drive shaft are supported by a second support member, the one side of the second drum and the other side of the drive shaft are supported by a third support member, and the other side of the second drum is supported by a fourth support member.
(11) A pallet lifting method according to the above item (10), in which the first drum and the second drum are pivotally supported on the first support member, the second support member, the third support member, and the fourth support member, respectively, via sliding bearings.

(12) In the above items (10) and (11), the drive shaft is supported above the first drum and the second drum by the second support member and the third support member when viewed from the side, and the motor is installed below the drive shaft between the second support member and the third support member.
(13) In the above items (10) and (11), a pallet lifting method is provided in which the second support member and the third support member are fixed to a beam extending in the lateral direction, and the first drum and the second drum are supported above the beam when viewed from the lateral direction, and the drive shaft is supported below the beam, and the motor is installed above the beam between the second support member and the third support member.
Furthermore, the pallet lifting methods described in paragraphs (8) to (13) are each performed using the pallet lifting mechanisms described in paragraphs (1) to (6) above, and thus have the same effect as the pallet lifting mechanisms described in paragraphs (1) to (6) above.

This configuration of the present invention makes it possible to reduce the space required for the pallet lifting mechanism.

1A and 1B are schematic diagrams showing the configuration of a pallet lifting mechanism for a first embodiment of the present invention, in which (a) is a front view, (b) is a partial side view showing the rotational force transmission portion from the drive shaft to the second drum together with the fourth support member, and (c) is a partial side view showing the rotational force transmission portion from the motor to the drive shaft together with the third support member. 10A and 10B are schematic diagrams showing the configuration of a pallet lifting mechanism for a second embodiment of the present invention, in which (a) is a front view, (b) is a partial side view showing the rotational force transmission portion from the drive shaft to the second drum together with the fourth support member, and (c) is a partial side view showing the rotational force transmission portion from the motor to the drive shaft together with the third support member. 10A and 10B are schematic diagrams showing the configuration of a pallet lifting mechanism for a third embodiment of the present invention, in which (a) is a front view, (b) is a partial side view showing the rotational force transmission portion from the drive shaft to the second drum together with the fourth support member, and (c) is a partial side view showing the rotational force transmission portion from the motor to the drive shaft together with the third support member. 1 is a perspective view schematically illustrating a lifting pallet that is lifted and lowered by a pallet lifting mechanism according to an embodiment of the present invention. 1 is a perspective view showing an example of the configuration of a multi-story parking system to which a pallet lifting mechanism according to an embodiment of the present invention is applied; 1A and 1B are schematic diagrams showing the configuration of a conventional pallet lifting mechanism, in which FIG. 1A is a front view and FIG. 1B is a partial side view showing a portion for transmitting rotational force from a motor to a drum.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, identical or corresponding parts will be designated by the same reference numerals throughout the drawings. Furthermore, detailed descriptions of parts that are identical or corresponding to those in the prior art will be omitted.
The pallet lifting mechanism according to the embodiment of the present invention lifts and lowers at least the lifting pallet 72 that moves up and down among a plurality of pallets 72 (72a to 72i) that store vehicles V in a multi-story parking system 70 as shown in Fig. 5. Each of these lifting pallets 72 is suspended by four wire ropes 52 (52a to 52d) as shown in Fig. 4, and is raised and lowered in the multi-story parking system 70 by winding and unwinding these four wire ropes 52.

As shown in FIG. 1, the pallet lifting mechanism 10 according to the first embodiment of the present invention is installed on a beam 50 provided in a multi-story parking system 70, and includes a first drum 12, a second drum 14, a motor 20, a drive shaft 30, a first support member 38, a second support member 40, a third support member 42, and a fourth support member 44. Hereinafter, unless otherwise noted, the left-right direction in FIG. 1(a) will be referred to as the lateral direction, the left side in FIG. 1(a) as one side of the lateral direction, the right side in FIG. 1(a) as the other side of the lateral direction, and the left-right direction in FIGS. 1(b) and (c) as the depth direction (the same applies to FIGS. 2 and 3 described below).

The first drum 12 winds and unwinds two of the four wire ropes 52 shown in FIG. 4 , and has grooves formed on its outer periphery to guide and position the wire ropes 52. One side of the first drum 12 is supported by the first support member 38, and the other side is supported by the second support member 40. In this embodiment, plain bearings 46 are embedded in both lateral ends of the first drum 12, and support shafts corresponding to the plain bearings 46 are inserted into the plain bearings 46 at both ends of the first drum 12 while being fixed to the first support member 38 and the second support member 40, respectively. It is preferable that the plain bearings 46 be oil-free plastic plain bearings. A drum sprocket 16 is provided on the other side of the first drum 12, and a chain 62 is looped around the drum sprocket 16. The first drum 12 is not limited to this, but may be, for example, a cast product that does not require welding.

The second drum 14 winds and unwinds two of the four wire ropes 52 shown in FIG. 4 , separate from the wire ropes on the first drum 12, and has a shape symmetrical to the first drum 12. One side of the second drum 14 is supported by the third support member 42, and the other side is supported by the fourth support member 44. In this embodiment, similar to the first drum 12, plain bearings 46 are embedded in both lateral ends of the second drum 14, and support shafts corresponding to the plain bearings 46 are inserted into the plain bearings 46 on both ends of the second drum 14 while being fixed to the third support member 42 and the fourth support member 44, respectively. A drum sprocket 16 is provided on one side of the second drum 14, and a chain 64 is looped around the drum sprocket 16. Similar to the first drum 12, the second drum 14 may be a cast product. Furthermore, the drum diameter D1 of the second drum 14 and the sprocket diameter S1 of the drum sprocket 16 are the same or approximately the same size, and in this embodiment, the drum diameter D1 is slightly larger than the sprocket diameter S1. This relationship also applies to the first drum 12, which has a symmetrical shape to the second drum 14.

Now, referring to Figure 4, we will discuss the wire ropes 52 wound around the first drum 12 and the second drum 14. As shown in the figure, the first drum 12 winds up two wire ropes 52a and 52b, out of the four wire ropes 52a to 52d that suspend the lifting pallet 72, that suspend one lateral side of the lifting pallet 72 (the diagonally lower left side in Figure 4). Of these, wire rope 52a suspends the front depth side of the lifting pallet 72 (the diagonally lower right side in Figure 4) via sheave 56, and wire rope 52b suspends the rear depth side of the lifting pallet 72 (the diagonally upper left side in Figure 4). In contrast, the second drum 14 reels in two wire ropes 52c and 52d, out of the four wire ropes 52a to 52d that suspend the lifting pallet 72, that suspend the other lateral side of the lifting pallet 72 (diagonally upper right side in Figure 4). Of these, wire rope 52c suspends the front side of the lifting pallet 72 in the depth direction via sheave 56, and wire rope 52d suspends the rear side of the lifting pallet 72 in the depth direction.

Returning to FIG. 1, the motor 20 generates rotational force for rotating the first drum 12 and the second drum 14 by rotating the rotating shaft 22, and a chain 60 is wound around the rotating shaft 22. The motor 20 is mounted on a beam 50 via a base 24, laterally between the second support member 40 and the third support member 42. The motor 20 may have a smaller reduction ratio and a smaller gear case than, for example, a conventional motor 120 such as that shown in FIG. 6. A motor that can be used for such a motor 20 may be, for example, a geared motor with a brake used in a chain-type pallet lifting mechanism that lifts and lowers a lifting pallet 72 suspended by a chain.

The drive shaft 30 transmits the rotational force generated by the motor 20 to the first drum 12 and the second drum 14. Above the motor 20, one lateral side is supported by the second support member 40, and the other lateral side is supported by the third support member 42. More specifically, one end of the drive shaft 30 is supported above the first drum 12 so as to protrude from the bearing portion of the second support member 40, and the other end of the drive shaft 30 is supported above the second drum 14 so as to protrude from the bearing portion of the third support member 42. A gear 34 is provided at one end of the drive shaft 30 protruding from the second support member 40, a gear 36 is provided at the other end of the drive shaft 30 protruding from the third support member 42, and a drive sprocket 32 is provided at a position corresponding to the rotating shaft 22 of the motor 20.

Furthermore, a chain 62 that is wound around the drum sprocket 16 of the first drum 12 is wound around the gear 34, a chain 64 that is wound around the drum sprocket 16 of the second drum 14 is wound around the gear 36, and a chain 60 that is wound around the rotating shaft 22 of the motor 20 is wound around the drive sprocket 32. With this configuration, the rotational force generated by the motor 20 is transmitted from the rotating shaft 22 via the chain 60 and drive sprocket 32 to the drive shaft 30, from which it is transmitted to the first drum 12 via the gear 34 and chain 62 and to the second drum 14 via the gear 36 and chain 64. In other words, a two-stage reduction structure is formed between the motor 20 and the first drum 12 and second drum 14, which is why the reduction ratio of the motor 20 can be made smaller than conventional, as described above. The drive shaft 30 may be a drive shaft used, for example, in a chain-type pallet lifting mechanism.

The first support member 38 and the fourth support member 44 are erected at both lateral ends of the beam 50. The second support member 40 and the third support member 42 are attached to the beam 50 at appropriate positions depending on the lateral dimensions of the first drum 12 and the second drum 14 and the lateral length of the drive shaft 30. In this state, the distance C1 from the lateral center of the pallet lifting mechanism 10 (equivalent to the lateral center of the beam 50) to the lateral center of the wire rope winding portion of the second drum 14 (similar to the first drum 12) is longer than the distance C5 in the conventional pallet lifting mechanism 100 shown in Figure 6, even though the lengths of the beam 50 and the conventional beam 130 are the same. Furthermore, in the conventional pallet lifting mechanism 100 shown in Figure 6, the required depth length L5 was specified to correspond to the sprocket diameter S5 of the sprocket 118. In contrast, in the pallet lifting mechanism 10 of Figure 1, the required depth length L1 is determined by the depth length of the third support member 42 (similarly to the second support member 40), which is smaller than the sprocket diameter S5 of the sprocket 118.

Here, specific numerical values are provided below to clarify the size relationships of several elements between the pallet lifting mechanism 10 of FIG. 1 and the conventional pallet lifting mechanism 100 shown in FIG. 6. However, the sizes of each element of the pallet lifting mechanism 10 are not limited to these. First, in the conventional mechanism of FIG. 6, the drum diameter D5 is approximately 200 mm and the sprocket diameter S5 is approximately 385 mm, whereas in FIG. 1, the drum diameter D1 is approximately 200 mm and the sprocket diameter S1 is approximately 195 mm, resulting in a significantly smaller sprocket diameter S1 (almost half). Furthermore, the distance C1 in FIG. 1 is approximately 94 mm larger than the conventional distance C5 in FIG. 6. Furthermore, the required depth length L5 in the conventional mechanism of FIG. 6 is approximately 415 mm, whereas in FIG. 1, the required depth length L1 is approximately 288 mm, resulting in a significantly smaller required length L1.

Next, with reference to Figure 2, a pallet lifting mechanism 10' according to a second embodiment of the present invention will be described. In Figure 2, parts that are the same as or equivalent to those in the pallet lifting mechanism 10 according to the first embodiment of the present invention shown in Figure 1 are designated by the same reference numerals. Note that, with regard to the pallet lifting mechanism 10' according to the second embodiment of the present invention, only the parts that differ from the pallet lifting mechanism 10 according to the first embodiment of the present invention will be described, and a description of the configuration of the parts that are similar to those in the pallet lifting mechanism 10 according to the first embodiment of the present invention will be omitted.

As shown in Figure 2, in the pallet lifting mechanism 10' according to the second embodiment of the present invention, the first drum 12, the second drum 14, and the drum sprocket 16 provided thereon are larger than those in the embodiment shown in Figure 1. Specifically, while the lateral dimensions of the first drum 12 and the second drum 14 are the same as those in Figure 1, the drum diameter D2 of the first drum 12 and the second drum 14 and the sprocket diameter S2 of the drum sprocket 16 are larger than the drum diameter D1 and sprocket diameter S1 in Figure 1. While not limited to these figures, specific numerical examples include a drum diameter D2 of approximately 345 mm and a sprocket diameter S2 of approximately 340 mm. Accordingly, the required depth length L2 of the pallet lifting mechanism 10' is approximately 355 mm to correspond to the drum diameter D2.

That is, the drum diameter D2 in FIG. 2 is larger than the conventional drum diameter D5 in FIG. 6 and the drum diameter D1 in FIG. 1. The sprocket diameter S2 in FIG. 2 is larger than the sprocket diameter S1 in FIG. 1 but smaller than the conventional sprocket diameter S5 in FIG. 6. Furthermore, the required depth length L2 in FIG. 2 is larger than the required depth length L1 in FIG. 1 but smaller than the conventional required depth length L5 in FIG. 6. Due to this increase in drum diameter D2, the length of the wire rope 52 wound by the first drum 12 and the second drum 14 increases. Furthermore, the distance C2 from the lateral center of the pallet lifting mechanism 10' in FIG. 2 to the lateral center of the wire rope winding portion of the second drum 14 remains the same as the corresponding distance C1 in FIG. 1, but is longer than the corresponding distance C5 in FIG. 6. Naturally, the length of the chains 62, 64 corresponds to the sprocket diameter S2.

Next, with reference to Figure 3, a pallet lifting mechanism 10" according to a third embodiment of the present invention will be described. In Figure 3, parts that are the same as or equivalent to those in the pallet lifting mechanism 10 according to the first embodiment of the present invention shown in Figure 1 are given the same reference numerals. Note that with regard to the pallet lifting mechanism 10" according to the third embodiment of the present invention, only the differences between it and the pallet lifting mechanism 10 according to the first embodiment of the present invention will be described, and a description of the configuration of the parts that are similar to those in the pallet lifting mechanism 10 according to the first embodiment of the present invention will be omitted.

As shown in FIG. 3, in a pallet lifting mechanism 10" according to a third embodiment of the present invention, the second support member 40 and the third support member 42 are attached to a beam 50 so that they extend both above and below the beam 50. The first drum 12 is supported above the beam 50 by the first support member 38 and a portion of the second support member 40 that extends above the beam 50. Similarly, the second drum 14 is supported above the beam 50 by the third support member 42 and a portion of the fourth support member 44 that extends above the beam 50. Meanwhile, the drive shaft 30 is supported below the beam 50 by the second support member 40 and the third support member 42. The motor 20 is installed on the beam 50 via a base 24, laterally between the second support member 40 and the third support member 42.

As a result, the beam 50 is positioned vertically between the first drum 12, the second drum 14, and the motor 20 and the drive shaft 30. The chain 60 is looped from the rotating shaft 22 of the motor 20, which is located above the beam 50, across the beam 50, to the drive sprocket 32 of the drive shaft 30, which is located below the beam 50. The chain 62 is looped from the gear 34 of the drive shaft 30, which is located below the beam 50, across the beam 50, to the drum sprocket 16 of the first drum 12, which is located above the beam 50. Similarly, the chain 64 is looped from the gear 36 of the drive shaft 30, which is located below the beam 50, across the beam 50, to the drum sprocket 16 of the second drum 14, which is located above the beam 50.

Note that, although not limited to these, the size of some of the components of the pallet lifting mechanism 10" includes the drum diameter D3 of the first drum 12 and the second drum 14, which is approximately the same as the drum diameter D1 in FIG. 1, and the sprocket diameter S3 of the drum sprocket 16, which is also approximately the same as the sprocket diameter S1 in FIG. 1. Furthermore, the distance C3 from the lateral center of the pallet lifting mechanism 10" in FIG. 3 to the lateral center of the wire rope winding portion of the second drum 14 is also approximately the same as the corresponding distance C1 in FIG. 1. Furthermore, the required depth length L3 of the pallet lifting mechanism 10" in FIG. 3 depends on various factors, but in the illustrated embodiment, it corresponds to the depth size of the motor 20. To give a specific example, it is approximately 255 mm, slightly smaller than the required depth length L1 in FIG. 1.

Next, Figure 5 shows an example of the configuration of a multi-story parking system 70 according to an embodiment of the present invention, which is equipped with a pallet lifting mechanism 10 (or 10', 10") according to an embodiment of the present invention. As shown, the multi-story parking system 70 has a structure in which multiple pallets 72 are movably supported on a substantially rectangular structure made up of multiple support columns and multiple beams. In the example of Figure 5, the multi-story parking system 70 has a four-tier, three-row structure on the ground (four tiers vertically and three rows horizontally), and is equipped with nine pallets 72a-72i as the multiple pallets 72, and further includes opening and closing gates 76 (76a-76c).

Of the multiple pallets 72a-72i, two pallets 72a and 72b only move laterally at a height position (entry/exit position) where vehicle V enters and exits, while four pallets 72c-72f can move vertically and sideways to the entry/exit position (the position where pallets 72a, 72b, and 72g are located in Figure 5) in response to a call operation by a user of the multi-story parking system 70. Meanwhile, the remaining three pallets 72g-72i only move up and down. The multi-story parking system 70 shown in Figure 5 has vehicles V stored on eight of the nine pallets 72a-72i, 72a-72f, 72h, and 72i, excluding pallet 72g. Furthermore, three pallets 72a, 72b, and 72g are in the entry/exit position, and the remaining six pallets 72c-72f, 72h, and 72i are in the storage position.

In a multi-story parking system 70 such as that shown in Figure 5, a pallet lifting mechanism 10 (10', 10") is provided for at least each lifting pallet 72 that moves up and down among the multiple pallets 72 provided in the multi-story parking system 70. That is, in the example of Figure 5, pallets 72c to 72f, which can move both vertically and laterally, and pallets 72g to 72i, which can move only vertically, correspond to the lifting pallets 72. Here, the pallet lifting mechanism 10 (10', 10") provided for the lifting pallets 72g to 72i that only move up and down basically has the positions of each component that do not change. In contrast, the pallet lifting mechanism 10 (10', 10") provided on the lifting pallets 72c to 72f, which perform both lateral movement and lifting, is installed so that each component follows the lateral movement of the lifting pallet 72, but does not follow the lifting and lowering of the pallet 72. Note that Figure 5 only shows the reference numeral for the pallet lifting mechanism 10 (10', 10") that lifts and lowers the lifting pallet 72g, and the configuration is also shown in a simplified form.

Each of the opening and closing gates 76a-76c opens after the desired pallet 72 is called to the entry/exit position behind it, and closes by user operation after the vehicle V has entered and exited the parking lot. Furthermore, while a detailed explanation will be omitted, the multi-story parking system 70 includes many other components in addition to the multiple pallets 72a-72i, opening and closing gates 76a-76c, and pallet lifting mechanism 10 (10', 10") described above. These components include, for example, a control panel through which users input inputs to operate the multi-story parking system 70; a control unit that controls the entire multi-story parking system 70; a drive unit that generates and transmits power to move the pallets 72 and open and close the opening and closing gates 76 in accordance with control by the control unit; and multiple photoelectric sensors that detect objects around each pallet 72 in the entry/exit position.

The pallet lifting mechanisms 10, 10', 10" according to embodiments of the present invention are not limited to the configuration shown in Figures 1 to 3 and can take various forms depending on the configuration and circumstances of the multi-story parking system 70 to which they are applied. For example, the first drum 12 and the second drum 14 may be supported via bearings other than the plain bearing 46. The shapes of the first support member 38, the second support member 40, the third support member 42, and the fourth support member 44 may be different from those shown in Figures 1 to 3. The multi-story parking system 70 according to embodiments of the present invention, which is equipped with the pallet lifting mechanisms 10, 10', 10", is also not limited to the configuration shown in Figure 5, and the number of pallets 72 and the number of opening and closing gates 76 may differ from the illustrated configuration. For example, the number of pallet 72 storage positions in the multi-story parking system 70 may be increased or decreased in the height or width directions from the configuration shown in Figure 5, and the multi-story parking system 70 may have two or more rows of storage positions in the depth direction.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained. That is, the pallet lifting mechanism 10, 10', 10" according to the embodiment of the present invention lifts and lowers the lifting pallet 72 via four wire ropes 52 as shown in FIG. 4, and includes a first drum 12, a second drum 14, a motor 20, and a drive shaft 30 as shown in FIGS. 1 to 3. As shown in FIG. 4, the first drum 12 winds and unwinds two of the four wire ropes 52, 52a and 52b, and these two wire ropes 52a and 52b suspends one lateral side of the lifting pallet 72, which corresponds to the width direction of the vehicle V. In contrast, the second drum 14 winds and unwinds the remaining two wire ropes 52c and 52d of the four wire ropes 52, and these two wire ropes 52c and 52d suspend the other lateral side of the lifting pallet 72. Returning to Figures 1 to 3, the motor 20 generates the rotational force to rotate the first drum 12 and second drum 14.

The drive shaft 30 transmits the rotational force generated by the motor 20 to the first drum 12 and the second drum 14, and is provided with a drive sprocket 32 for receiving the rotational force from the motor 20. Furthermore, each of the first drum 12 and the second drum 14 is provided with a drum sprocket 16 for receiving the rotational force from the drive shaft 30. Therefore, the rotational force generated by the motor 20 is transmitted to the drive shaft 30 via the drive sprocket 32 provided on the drive shaft 30, and is further transmitted from the drive shaft 30 to the first drum 12 and the second drum 14 via the drum sprockets 16 provided on the first drum 12 and the second drum 14. In other words, rotational force can be transmitted individually from the motor 20 to the first drum 12 and from the motor 20 to the second drum 14 via the drive shaft 30.

As a result, compared to a conventional structure in which rotational force is transmitted from the motor 120 to the drum shaft 110 to which two drums 112, 114 are connected, as shown in Figure 6, the torque required to rotate each of the first drum 12 and the second drum 14 is halved, making it possible to reduce the sprocket diameter S1 of the drum sprockets 16 provided on the first drum 12 and the second drum 14, as shown in Figures 1 and 3 in particular. In addition, by adopting a two-stage reduction structure via the drive shaft 30, the required reduction ratio of the motor 20 is reduced, allowing the gear case of the motor 20 to be made more compact. As a result, the pallet lifting mechanism 10, 10', 10" as a whole can be made more space-saving, and the space saved can be used for a variety of purposes.

For example, in the pallet lifting mechanism 10 according to the first embodiment shown in FIG. 1, the first drum 12 and second drum 14 may be installed at a lower position than shown, and other components may be moved downward accordingly, thereby further saving space. Furthermore, the free space may be used to install a drum for winding up a charging cable for an electric vehicle. In this case, by matching the drum diameters of the charging cable winding drum with the first drum 12 and second drum 14, it is possible to unwind the charging cable in accordance with the lifting stroke of the lifting pallet 72. Furthermore, by miniaturizing the gear case of the motor 20 as described above, it is possible to use a geared motor with a brake, the same as that used in chain-type pallet lifting mechanisms, as the motor 20, thereby enabling the sharing of components.

Furthermore, because the first drum 12 and the second drum 14 are individually supported, the required precision for axial runout can be relaxed compared to the conventional structure in which both ends of the drum shaft 110 to which the two drums 112, 114 are connected are supported, as shown in Figure 6. Furthermore, because the connecting shaft 116 that conventionally connected the two drums 112, 114 is no longer necessary, the welding required for such a connection is also no longer necessary, making it possible to reduce the manufacturing costs and component costs of the individual drums. Furthermore, because the elimination of the conventional drum connecting shaft 116 simplifies the drum structure, for example, even if the lateral size of the lifting pallet 72 changes, it can be flexibly accommodated by adjusting the installation positions of the first drum 12 and the second drum 14 without having to change the design of the drums themselves.

In addition, in the pallet lifting mechanisms 10, 10', 10" according to the embodiments of the present invention, the drum diameters D1, D2 of the first drum 12 and the second drum 14 and the sprocket diameters S1, S2 of the drum sprockets 16 provided thereon are the same or approximately the same. Therefore, when the sprocket diameter S1 of the drum sprocket 16 is made smaller than conventional, as in the first embodiment shown in Figure 1 and the third embodiment shown in Figure 3, the drum diameters D1 of the first drum 12 and the second drum 14 and the sprocket diameter S1 of the drum sprocket 16 are set to be approximately the same as the drum diameter D5 of the conventional drums 112, 114 shown in Figure 6, for example. The space secured in this way can then be used for any purpose.

At least a portion of the space gained as described above may be used to increase the drum diameter D2 of the first drum 12 and the second drum 14, as in the second embodiment shown in Figure 2. That is, the drum diameter D2 of the first drum 12 and the second drum 14 is made larger than that of the conventional drums 112 and 114, and the sprocket diameter S2 of the drum sprockets 16 provided thereon is adjusted to match the drum diameter D2. This allows the winding length of the wire rope 52 to be increased compared to conventional systems without changing the lateral size or installation space of the first drum 12 and the second drum 14, thereby increasing the lifting stroke of the first drum 12 and the second drum 14. This allows for the lifting and lowering of lifting pallets 72 located higher than conventional systems, addressing the need for taller multi-story parking systems 70. For example, the winding length of a single wire rope 52 can be doubled from approximately 8 m to approximately 16 m, enabling the system to accommodate multi-story parking systems 70 with six to eight pallet storage levels.

Furthermore, the pallet lifting mechanism 10, 10', 10" according to an embodiment of the present invention further includes a first support member 38, a second support member 40, a third support member 42, and a fourth support member 44. The first support member 38 supports one lateral side of the first drum 12, and the second support member 40 supports the other lateral side of the first drum 12 and one lateral side of the drive shaft 30. The third support member 42 supports the other lateral side of the drive shaft 30 and one lateral side of the second drum 14, and the fourth support member 44 supports the other lateral side of the second drum 14.

As can be seen in Figures 1 to 3, the first drum 12, drive shaft 30, and second drum 14 are arranged from one side to the other in the order shown. The first drum 12 has a drum sprocket 16 on its other side, adjacent to one side of the drive shaft 30 in the lateral direction, and the second drum 14 has a drum sprocket 16 on its one side, adjacent to the other side of the drive shaft 30 in the lateral direction. This structure makes it possible to position the first drum 12 and second drum 14 in appropriate lateral positions for winding up the four wire ropes 52, while also ensuring that rotational force is transmitted to them from the motor 20 via the drive shaft 30.

Furthermore, in the pallet lifting mechanisms 10, 10', 10" according to the embodiments of the present invention, the first drum 12 and the second drum 14 are journalled to the first support member 38 to the fourth support member 44 via slide bearings 46. By journalling with such a simple structure, the number and size of the components used can be reduced. For this reason, while maintaining the same lateral installation range (length of the beam 50) as conventionally, the first drum 12 and the second drum 14 are positioned as far outward as possible in the lateral direction; in other words, the first drum 12 is positioned as far to one side as possible in the lateral direction, and the second drum 14 is positioned as far to the other side as possible in the lateral direction. For example, the distances C1, C2, C3 from the lateral centre of the pallet lifting mechanisms 10, 10', 10" shown in Figures 1 to 3 to the lateral centre of the wire rope take-up portion of the second drum 14 are greater than the distance C5 from the lateral centre of the conventional pallet lifting mechanism 100 shown in Figure 6 to the lateral centre of the wire rope take-up portion of the drum 114.

If the newly gained space in the lateral direction is used to expand the lateral size of the first drum 12 and the second drum 14, the amount of wire rope 52 wound by the first drum 12 and the second drum 14 will increase, making it possible to increase the lifting stroke. Alternatively, by shifting the first drum 12 and the second drum 14 outward in the lateral direction, the suspension position of the lifting pallet 72 by the four wire ropes 52 will also shift outward, making it possible to increase the width of the vehicle V that can be accommodated on the lifting pallet 72. Furthermore, using a self-lubricating resin sliding bearing as the sliding bearing 46 makes handling easier.

Furthermore, as shown in FIGS. 1 and 2, in the pallet lifting mechanisms 10, 10' according to the first and second embodiments of the present invention, the second support member 40 and the third support member 42 support the drive shaft 30 above the first drum 12 and the second drum 14 when viewed from the side. Therefore, a chain 62 is looped around the vicinity of one lateral end of the drive shaft 30 and the drum sprocket 16 of the first drum 12 located below it, and rotational force is transmitted from the drive shaft 30 to the first drum 12 via this chain 62. Similarly, a chain 64 is looped around the vicinity of the other lateral end of the drive shaft 30 and the drum sprocket 16 of the second drum 14 located below it, and rotational force is transmitted from the drive shaft 30 to the second drum 14 via this chain 64.

Furthermore, since the motor 20 is installed below the drive shaft 30 between the second support member 40 and the third support member 42, a chain 60 is looped around the rotating shaft 22 of the motor 20 and the drive sprocket 32 of the drive shaft 30 located above it, and rotational force is transmitted from the motor 20 to the drive shaft 30 via this chain 60. This arrangement allows the positions of the components to be concentrated in the depth direction, which is perpendicular to the lateral direction in a plan view, thereby enabling space savings, particularly in the depth direction. This is evident from the required depth length L1 in Figure 1, the required depth length L2 in Figure 2, and the required depth length L5 in Figure 6. Furthermore, since the motor 20 is installed below the drive shaft 30, the motor 20 can be installed at a lower position than before, simplifying the structure of the base 24 for the motor 20.

In addition, as shown in FIG. 3, in the pallet lifting mechanism 10" according to the third embodiment of the present invention, the second support member 40 and the third support member 42 are fixed to the beam 50 and support each component. That is, when viewed from the side, the second support member 40 and the third support member 42 support the first drum 12 and the second drum 14 above the beam 50, and support the drive shaft 30 below the beam 50, thereby positioning the beam 50 between the first drum 12 and the second drum 14 and the drive shaft 30 in the height direction. As a result, a chain 62 is looped around the vicinity of one lateral end of the drive shaft 30 and the drum sprocket 16 of the first drum 12 located above it, across the beam 50, and rotational force is transmitted from the drive shaft 30 to the first drum 12 via this chain 62.

Similarly, a chain 64 is looped around the vicinity of the other lateral end of the drive shaft 30 and the drum sprocket 16 of the second drum 14, which is located above the drive shaft 30 across the beam 50. Torque is transmitted from the drive shaft 30 to the second drum 14 via this chain 64. The motor 20 is installed above the beam 50 between the second support member 40 and the third support member 42, with the beam 50 positioned between the motor 20 and the drive shaft 30 in the height direction. Therefore, a chain 60 is looped around the rotation shaft 22 of the motor 20 and the drive sprocket 32 of the drive shaft 30, which is located below the motor 20 across the beam 50. Torque is transmitted from the motor 20 to the drive shaft 30 via this chain 60. This arrangement allows the positions of the components to be concentrated in the depth direction, which is perpendicular to the lateral direction in a plan view, thereby achieving space savings, particularly in the depth direction. This is also clear from the required depth length L3 in Figure 3 and the required depth length L5 in Figure 6.

Furthermore, by locating the drive shaft 30 below the beam 50, it is possible to effectively utilize the space below the beam 50 while minimizing the required vertical space for components installed above the beam 50. Furthermore, by installing the first drum 12 and the second drum 14 as high as possible within the limited installation space, the wire rope 52 can be unwound from a higher position, allowing the lifting pallet 72 to be suspended at a higher position. Furthermore, by locating the beam 50 between the first drum 12 and the second drum 14 and the drive shaft 30, and between the motor 20 and the drive shaft 30, the vertical distance between the drum sprocket 16 and the drive shaft 30 and the vertical distance between the rotating shaft 22 of the motor 20 and the drive sprocket 32 of the drive shaft 30 are increased. This increases the length of the chains 60, 62, and 64 wound around them, enabling the chain drive to be stabilized.

On the other hand, as shown in Figure 5, the multi-story parking device 70 according to an embodiment of the present invention includes a plurality of pallets 72 for accommodating vehicles V, and is provided with a pallet lifting mechanism 10, 10', 10" as described above for each of the lifting pallets 72 that move up and down at least among the plurality of pallets 72.This allows for the same effects as the pallet lifting mechanisms 10, 10', 10" according to an embodiment of the present invention, thereby making it possible to improve the added value of the multi-story parking device 70.
On the other hand, the pallet lifting method according to the embodiment of the present invention can achieve the same effects as the pallet lifting mechanisms 10, 10', 10" by being carried out using the pallet lifting mechanisms 10, 10', 10" according to the embodiment of the present invention as described above.

10, 10', 10": pallet lifting mechanism, 12: first drum, 14: second drum, 16: drum sprocket, 20: motor, 30: drive shaft, 32: drive sprocket, 38: first support member, 40: second support member, 42: third support member, 44: fourth support member, 46: sliding bearing, 50: beam, 52 (52a to 52d): wire rope, 70: multi-story parking device, 72 (72a to 72i): multiple pallets (lifting pallets), V: vehicle, D1, D2, D3: drum diameter, S1, S2, S3: sprocket diameter

Claims (13)

A pallet lifting mechanism for lifting and lowering at least each of the lifting and lowering pallets that move up and down via four wire ropes suspending the lifting and lowering pallets in a multi-story parking device having a plurality of pallets for accommodating vehicles,
a first drum for winding and unwinding two of the four wire ropes that suspend one side of the lifting pallet in a lateral direction corresponding to the width direction of the vehicle;
a second drum for winding and unwinding two of the four wire ropes that suspend the other side of the lifting pallet in the lateral direction;
a motor that generates a rotational force;
a drive shaft for transmitting rotational force;
A pallet lifting mechanism characterized in that a drive sprocket is provided on the drive shaft to receive rotational force from the motor, and a drum sprocket is provided on each of the first drum and the second drum to receive rotational force from the drive shaft. A pallet lifting mechanism as described in claim 1, characterized in that the drum diameters of the first drum and the second drum and the sprocket diameter of the drum sprocket are the same or approximately the same. a first support member that pivotally supports the one side of the first drum;
a second support member that pivotally supports the other side of the first drum and the one side of the drive shaft;
a third support member that pivotally supports the one side of the second drum and the other side of the drive shaft;
3. The pallet lifting mechanism according to claim 1, further comprising: a fourth support member that pivotally supports the other side of the second drum. A pallet lifting mechanism as described in claim 3, characterized in that the first drum and the second drum are journaled to the first support member, the second support member, the third support member, and the fourth support member, respectively, via slide bearings. the second support member and the third support member support the drive shaft above the first drum and the second drum as viewed in the side direction,
5. The pallet lifting mechanism according to claim 3, wherein the motor is installed below the drive shaft between the second support member and the third support member. the second support member and the third support member are fixed to a beam extending in the lateral direction, and pivotally support the first drum and the second drum above the beam as viewed in the lateral direction, and pivotally support the drive shaft below the beam;
5. The pallet lifting mechanism according to claim 3, wherein the motor is installed above the beam between the second support member and the third support member. A multi-story parking system comprising a plurality of pallets for accommodating vehicles, characterized in that at least each of the lifting pallets that move up and down is equipped with a pallet lifting mechanism according to any one of claims 1 to 6. A pallet lifting method for lifting and lowering at least each of the lifting and lowering pallets that move up and down via four wire ropes suspending the lifting and lowering pallets in a multi-story parking device equipped with a plurality of pallets for accommodating vehicles, comprising:
a first drum, a second drum, a motor, and a drive shaft;
The first drum winds and unwinds two of the four wire ropes that suspend one side of the lifting pallet in a lateral direction corresponding to the width direction of the vehicle,
The second drum winds and unwinds two of the four wire ropes that suspend the other side of the lifting pallet in the lateral direction,
A pallet lifting method characterized in that a drive sprocket provided on the drive shaft receives the rotational force generated by the motor, and drum sprockets provided on each of the first drum and the second drum receive the rotational force from the drive shaft. A pallet lifting method as described in claim 8, characterized in that the drum diameters of the first drum and the second drum and the sprocket diameter of the drum sprocket are the same or approximately the same. The one side of the first drum is pivotally supported by a first support member,
the other side of the first drum and the one side of the drive shaft are pivotally supported by a second support member;
the one side of the second drum and the other side of the drive shaft are pivotally supported by a third support member;
10. A pallet lifting method according to claim 8, wherein the other side of the second drum is pivotally supported by a fourth support member. A pallet lifting method as described in claim 10, characterized in that the first drum and the second drum are pivotally supported on the first support member, the second support member, the third support member, and the fourth support member, respectively, via slide bearings. the drive shaft is supported by the second support member and the third support member above the first drum and the second drum as viewed in the side direction,
12. The pallet lifting method according to claim 10, wherein the motor is installed below the drive shaft between the second support member and the third support member. the second support member and the third support member are fixed to a beam extending in the lateral direction, and pivotally support the first drum and the second drum above the beam as viewed in the lateral direction, and pivotally support the drive shaft below the beam;
12. The pallet lifting method according to claim 10, wherein the motor is installed above the beam between the second support member and the third support member.