JP7568191B2 - Article lifting device - Google Patents

Description

The present invention relates to an article lifting device that lifts and lowers articles on multiple upper and lower levels of a shelf system.

As an article lifting device for use in a rack facility with multiple upper and lower levels to raise and lower articles on the levels, there is one in which an upper sprocket is provided on the top of the article lifting device, a carriage is attached to one end of a hanging chain hung on the upper sprocket, a counterweight is attached to the other end of the hanging chain, and the upper sprocket is driven by a drive device to raise and lower the carriage in a bucket-like manner (see, for example, Patent Document 1. Hereinafter, this will be referred to as an "upper drive type article lifting device").

In addition, there is an article lifting device in which an upper sprocket is provided at the top of the article lifting device and a lower sprocket is provided at the bottom of the article lifting device, a chain is stretched in a loop shape, and the lower sprocket is driven by a drive device to raise and lower the carriage in a bucket-type manner (for example, see Patent Document 2. Hereinafter, this will be referred to as a "bottom-drive type article lifting device").

For example, a bottom-drive type article lifting device has a carriage and a counterweight attached to one end and the other end of a hanging chain hung on an upper sprocket, and a carriage and a counterweight attached to one end and the other end of a return chain hung on a lower sprocket.

In an upper drive type article lifting device, tension is always applied to the hanging chain even if it stretches, so the hanging chain is always in a taut state. In contrast, in a lower drive type article lifting device, the hanging chain is always in a taut state, but tension is not always applied to the return chain. Therefore, in a lower drive type article lifting device, the return chain slackens as the hanging chain and the return chain stretch.

Since loosening of the return chain can lead to a very serious accident in which the return chain comes off the lower sprocket driven by the drive device, bottom-drive type item lifting devices are provided with a take-up mechanism that applies tension to the return chain.

For example, the take-up mechanism in the prior art of the invention of Patent Document 2 is provided at the point where the return chain is connected to the carriage, which is the attachment point of the chain tensioned in a loop shape (such as a spring for pulling up the chain). Also, the take-up mechanism (28) in the invention of Patent Document 2 is not an attachment point of the chain tensioned in a loop shape, but rather, the return chain (11B, 12B) is hung on a movable sprocket (19, 20) provided on the carriage (9) side of the drive sprocket (17, 18), and tension is applied to the return chain (11B, 12B) via the movable sprocket (19, 20) by biasing the movable sprocket (19, 20) with a spring (31).

JP 2019-48700 A Special Publication No. 6-562

In an article lifting device equipped with a counterweight, the main factor in determining the capacity of the drive unit (the capacity of the motor and reducer, or the capacity of the geared motor) is the power required by the load. The power required by the load is determined by the conveying speed and the unbalanced load. In other words, the capacity of the drive unit can be minimized by minimizing the unbalanced load. Here, the unbalanced load is the difference in weight between the carriage side and the counterweight side.

In an upper drive type article lifting device, in order to minimize the unbalanced load and minimize the capacity of the drive unit, the appropriate weight of the counterweight, Wcw, is the weight of the carriage Wc plus half (Ww/2) of the weight Ww of the goods (cargo) to be placed on the carriage. In other words, Wcw = Wc + Ww/2. As a result, the unbalanced load becomes Ww/2 whether there is a load or not, and since the unbalanced load is minimized, the capacity of the drive unit can be minimized. The ability to minimize the capacity of the drive unit in this way is an advantage of an upper drive type article lifting device.

However, with an upper drive type goods lifting device, heavy objects such as the drive device must be installed on top of the goods lifting device, which is at a high altitude. Installation and maintenance work of heavy objects at high altitudes is dangerous, reducing workability. Furthermore, it is necessary to install walkways and handrails for work involving handling heavy objects above the goods lifting device, which increases costs. Furthermore, it is necessary to provide a work space above the goods lifting device for workers to install heavy objects and perform maintenance and inspection work, which limits the lifting height of the goods lifting device.

Because bottom-drive type item lifting devices do not have heavy objects such as the drive device located at a high place, they do not have the problems mentioned above with top-drive type item lifting devices, meaning that the building can be used more effectively and maintainability can be improved.

As an example of a bottom drive type article lifting device, consider one equipped with the take-up mechanism (28) in the invention of Patent Document 2. As with the top drive type article lifting device, the weight Wcw of the counterweight (W) is assumed to be the weight Wc of the carriage (9) plus half the weight Ww of the load (Ww/2). In other words, Wcw = Wc + Ww/2. Also, assume Wcw = 900 kg, Wc = 500 kg, and Ww = 800 kg.

When there is no load, the unbalanced load (Wcw-Wc=Ww/2=400 kg) causes the carriage (9) to be pulled upward. In this case, the drive sprockets (17, 18) are controlled by the motor (40) to rotate, so they try to prevent the carriage (9) from being pulled upward. However, the spring (31) of the take-up mechanism (28) only has a small spring force that is enough to take up the slack in the return chain (11B, 12B) under normal conditions, so the tensile force (400 kg) of the carriage (9) is greater, and the spring (31) is compressed.

As a result, the take-up movable sprockets (19, 20) are pulled to the left in FIG. 2 of Patent Document 2, the carriage (9) is pulled upward by the counterweight (W), and the counterweight (W) moves downward. This causes the return side chain (11B, 12B) between the bottom end of the counterweight (W) and the drive sprockets (17, 18) to slacken, which can lead to an accident where the chain comes off the drive sprockets (17, 18).

To prevent such accidents, the weight Wcw of the counterweight (W) must be less than the weight Wc of the carriage (9) (carriage weight - α) so that the carriage (9) is not pulled upward by the counterweight (W) even when there is no load. Here, α is a load that takes into account the unbalanced load of the chain when the carriage (9) is at its upper limit and the inertial load when accelerating from start.

In a bottom-drive type goods lifting device, if the carriage weight Wc = 500 kg, the load weight Ww = 800 kg, and the counterweight weight Wcw is less than the carriage weight (Wcw < Wc), for example Wcw = 450 kg, then the unbalanced load (Wc + Ww - Wcw) when there is a load is 850 kg, and the unbalanced load (Wc - Wcw) when there is no load is 50 kg. Therefore, the capacity of the drive unit must be selected based on the maximum unbalanced load of 850 kg. Therefore, a bottom-drive type goods lifting device has the problem that the capacity of the drive unit that drives the lower sprocket (the capacity of the motor and reducer, or the capacity of the geared motor) is large (almost twice the capacity of the drive unit in a top-drive type goods lifting device).

The present invention aims to reduce the capacity of the drive device in a bottom-drive type article lifting device.

The gist of the present invention is as follows.
[1]
In an article lifting device that lifts and lowers an article on a carriage,
The carriage and the counterweight are suspended in a suspending manner by a suspending chain that engages with an upper driven sprocket disposed on an upper portion of the article lifting device;
One end of a drive chain that engages with a drive sprocket arranged at a lower portion of the article lifting device is connected to a lower end of the carriage or a lower end of the suspension chain that suspends the carriage;
The other end of the drive chain is connected to the counterweight,
An article lifting device that lifts and lowers the carriage and the counterweight along a guide column by driving the drive sprocket with a drive device,
the drive chain between the drive sprocket and the carriage;
A take-up device is provided on the carriage side,
the drive chain between the drive sprocket and the counterweight;
A counterweight side take-up device is provided ,
The carriage side take-up device and the counterweight side take-up device are
a take-up sprocket that engages with the drive chain and is movable in a direction to apply tension to the drive chain and in a direction opposite thereto;
a biasing member that biases the take-up sprocket in a direction that applies tension to the drive chain; and
a take-up stopper that restricts the movement of the take-up sprocket in a direction against the biasing force of the biasing member at a predetermined position;
Equipped with
Goods lifting device.

[2]
a first lower driven sprocket is provided at a lower end of the drive chain that depends from the carriage, and a second lower driven sprocket is provided at a lower end of the drive chain that depends from the counterweight;
The drive sprocket is disposed between the drive chain that is suspended from the carriage and redirected by the first lower driven sprocket and the drive chain that is suspended from the counterweight and redirected by the second lower driven sprocket;
the carriage side take-up device is provided on the drive chain between the first lower driven sprocket and the drive sprocket;
The counterweight side take-up device is provided on the drive chain between the second lower driven sprocket and the drive sprocket.
An article lifting device as described in [1].

[ 3 ]
The weight of the counterweight is equal to or greater than the weight of the carriage.
The article lifting device according to [1] or [ 2] .

[ 4 ]
a chain breakage detection device for detecting breakage of the drive chain is provided in one or both of the carriage side take-up device and the counterweight side take-up device;
An article lifting device according to any one of [1] to [ 3 ].

[ 5 ]
a chain end of the driving chain on the carriage side is connected to a chain end of the suspension chain on the carriage side;
the carriage is positioned relative to the carriage-side chain end of the suspension chain and the carriage-side chain end of the drive chain in a state in which the carriage abuts against a stopper member provided at the carriage-side chain end of the suspension chain or the carriage-side chain end of the drive chain,
The carriage is movable upward relative to the stopper member.
An article lifting device according to any one of [1] to [ 4 ].

According to the article lifting device of the present invention, since it is a bottom drive type, it is possible to effectively utilize the building and improve the maintainability. Moreover, in the bottom drive type article lifting device, a carriage side take-up device is provided on the drive chain between the drive sprocket and the carriage, and a counterweight side take-up device is provided on the drive chain between the drive sprocket and the counterweight, so that the weight of the counterweight can be made large like that of the top drive type article lifting device, and the capacity of the drive device can be reduced. Moreover, since a take-up stopper is provided that restricts the movement of the take-up sprocket in a direction against the biasing force of the biasing member at a predetermined position, the take-up stopper can suppress excessive compression of the biasing member, and the take-up stopper can resist the tension (tensile force) of the drive chain. Since the biasing member is not used to counter the tensile force of the drive chain alone, but the take-up stopper can be provided to reduce the size of the biasing member, the manufacturing cost can be reduced. Moreover, by reducing the size of the biasing member, the normal chain tension can be reduced.

1 is a schematic front view showing an example in which an article lifting device according to an embodiment of the present invention is used in a shelf system. 2 is an enlarged schematic front view of the main upper and lower parts of the article lifting device. FIG. 4 is a schematic front view in partial vertical section of a carriage-side take-up device and a counterweight-side take-up device; FIG. FIG. 2 is a schematic front view of the counterweight-side take-up device. FIG. 2 is a schematic right side view in partial vertical section of the counterweight-side take-up device. FIG. 4 is a left side view in partial vertical section showing the vicinity of the chain end on the carriage side of the hanging chain. FIG. 4 is a partial vertical sectional front view showing the carriage side chain end and its surroundings of the suspension chain. 11 is a left side view, partially in vertical section, showing the vicinity of the chain end on the carriage side of the hanging chain, in a state in which the carriage has moved upward relative to the stopper member. FIG. 11 is a schematic front view showing the operation of the take-up device when no article is loaded on the carriage. FIG. 11 is a schematic front view showing the operation of the take-up device when an article is loaded on the carriage. FIG. 11 is a schematic front view showing the operation of the take-up device when the carriage stops at each floor, leveling is performed using the level lock device, and the weight of the carriage is placed on the structure of the article lifting device. FIG. 10 is a schematic front view showing the operation of the take-up device. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

In the following embodiment, the direction perpendicular to the paper surface of FIG. 1 is referred to as the front, and the view from the front is referred to as the front view.

<Shelf equipment>
1 is a schematic front view showing an example in which an article lifting device 1 according to an embodiment of the present invention is used in a shelf system A. The shelf system A has a three-dimensional article storage space B with multiple upper and lower levels, and is equipped with the article lifting device 1 that lifts and lowers an article W placed on a carriage C.

<Article lifting device>
As shown in the schematic front view of Figure 1 and the enlarged schematic front view of essential parts of Figure 2, an article lifting device 1 according to an embodiment of the present invention has upper driven sprockets 6A-6C arranged at the top and lower driven sprockets 7A-7C arranged at the bottom.

(Hanging chain)
The hanging chain 2 engages with the upper driven sprocket 6A, and hangs a carriage C from a chain end 2A at one end of the hanging chain 2, and hangs a counterweight CW from a chain end 2B at the other end of the hanging chain 2.

The hanging chain 3 engages with the upper driven sprockets 6B, 6C, and hangs the carriage C from the chain end 3A at one end of the hanging chain 3, and hangs the counterweight CW from the chain end 3B at the other end of the hanging chain 3.

In this way, the article lifting device 1 suspends the carriage C and counterweight CW in a tethered manner using the suspension chains 2 and 3.

(Drive chain)
A chain end 4A at one end of the drive chain 4 is connected to a chain end 2A at the lower end of the suspension chain 2, and a chain end 4B at the other end of the drive chain 4 is connected to a counterweight CW. Note that the chain end 4A at one end of the drive chain 4 may be connected to the carriage C instead of the chain end 2A at the lower end of the suspension chain 2.

A first lower driven sprocket 7A is provided at the lower end of the drive chain 4 hanging down from the carriage C, and a second lower driven sprocket 7B is provided at the lower end of the drive chain 4 hanging down from the counterweight CW. The drive chain 4 engages with the lower driven sprockets 7A and 7C, the take-up sprocket 8, the drive sprocket 5 driven by the drive unit D, the take-up sprocket 9, and the lower driven sprocket 7B.

(Counterweight weight)
In the present invention, a carriage-side take-up device TU1 and a counterweight-side take-up device TU2, the details of which will be described later, are provided. As a result, in the bottom-drive type article lifting device 1, the weight Wcw of the counterweight CW can be made large like that of the top-drive type article lifting device, so the weight Wcw of the counterweight CW is set to the weight Wc of the carriage C plus half the weight Ww of the article (cargo) W placed on the carriage C. In other words, Wcw = Wc + Ww/2.

For example, if the weight Wc of the carriage C is 500 kg and the weight Ww of the load W is 800 kg, then the weight Wcw of the counterweight CW is 500 + 800/2 = 900 kg. As a result, with the carriage C and counterweight CW suspended in a bucket-like manner, if there is load W, the carriage C side will be 400 kg (500 kg + 800 kg - 900 kg) heavier, and if there is no load W, the counterweight side will be 400 kg (900 kg - 500 kg) heavier. Note that the weight Wcw of the counterweight CW can be made equal to or greater than the weight Wc of the carriage C (Wcw ≧ Wc).

(Drive unit)
A drive sprocket 5 is disposed between a drive chain 4 that hangs down from the carriage C and has its direction changed by a first lower driven sprocket 7A, and a drive chain 4 that hangs down from the counterweight CW and has its direction changed by a second lower driven sprocket 7B. The carriage C and the counterweight CW are raised and lowered along a guide post H (FIG. 1) via the drive chain 4 by driving the drive sprocket 5 with a drive unit D, which is, for example, an orthogonal shaft geared motor.

As shown in this embodiment, by setting the weight Wcw of the counterweight CW to the weight Wc of the carriage C plus half the weight of the load W (Wcw = Wc + Ww/2), the unbalanced load, which is the difference in weight between the carriage side and the counterweight side, becomes the same when there is a load W and when there is no load W, so the capacity of the drive unit D can be reduced.

(Take-up device)
The article lifting device 1 is provided with a carriage-side take-up device TU1 on the drive chain 4 between the drive sprocket 5 and the carriage C, and a counterweight-side take-up device TU2 on the drive chain 4 between the drive sprocket 5 and the counterweight CW.

In this embodiment, the carriage-side take-up device TU1 is provided on the drive chain 4 between the first lower driven sprocket 7A, which is provided at the lower end of the drive chain 4 hanging down from the carriage C, and the drive sprocket 5. The counterweight-side take-up device TU2 is provided on the drive chain 4 between the second lower driven sprocket 7B, which is provided at the lower end of the drive chain 4 hanging down from the counterweight CW, and the drive sprocket 5.

With this configuration, compared to a configuration in which a take-up device is provided at the point where the drive chain 4 is connected to the carriage C, the strength of the spring in the carriage-side take-up device TU1 can be reduced because there is no need to pull up the weight of the drive chain 4 (see, for example, Figure 9) hanging down from the carriage C with a take-up device below the carriage C. This allows for cost reduction and compactness.

Next, the structure of the take-up device will be described with reference to the partial vertical sectional schematic front view of FIG. 3, the schematic front view of FIG. 4, and the partial vertical sectional schematic right side view of FIG. 5.

The carriage side take-up device TU1 applies tension to the drive chain 4 by engaging the take-up sprocket 8, which rotates around the support shaft 8A, with the drive chain 4. The counterweight side take-up device TU2 applies tension to the drive chain 4 by engaging the take-up sprocket 9, which rotates around the support shaft 9A, with the drive chain 4.

The carriage side take-up device TU1 and the counterweight side take-up device TU2 have the same structure, so we will use the counterweight side take-up device TU2 as a representative and explain its structure.

The support shaft 9A is fixed to the support frame 10, and the take-up sprocket 9 is rotatably supported by the support shaft 9A via a bearing. The support frame 10 is supported by a guide member G so that it can slide vertically. This allows the take-up sprocket 9 to move in the direction that applies tension to the drive chain 4 (upward) and in the opposite direction (downward).

The lower end of a vertically long connecting shaft 11 is fixed to the top of the support frame 10. The connecting shaft 11 is inserted into a coil spring 13 in a support tube 12 located on the upper side of the take-up frame F, and into a circular member E fixed to the upper end of the support tube 12, and is screwed into a double nut K on the upper side of the circular member E.

With this configuration, when slack occurs in the drive chain 4 as described below, the coil spring 13 urges the support tube 12, connecting shaft 11, and take-up sprocket 9 upward and moves them, applying tension to the drive chain 4. In this case, as shown in FIG. 12, a gap SK is created between the take-up stopper S, which is the lower end surface 12A of the support tube 12, and the take-up frame F. In this way, instead of the coil spring 13, an air cylinder, for example, may be used as the urging member that applies tension to the drive chain 4.

Movement of the take-up sprocket 9 in a direction (downward) that resists the upward biasing force of the coil spring 13 is restricted at a predetermined position where the take-up stopper S, which is the lower end surface 12A of the support tube 12, abuts the take-up frame F. Such a take-up stopper S can suppress excessive compression of the coil spring 13, and can resist the tension (tensile force) of the drive chain 4. By providing the take-up stopper S, rather than resisting the tensile force of the drive chain 4 with only a spring, the spring can be made smaller, reducing manufacturing costs. Furthermore, by making the spring smaller, the normal chain tension can be reduced.

(Drive chain breakage detection device)
4 and 5, the counterweight side take-up device TU2 is provided with a chain breakage detection device I, e.g., a limit switch, which detects the breakage of the drive chain 4 by detecting the position of the support cylinder 12 which moves upward due to the biasing force of the coil spring 13 when the drive chain 4 breaks. Such a chain breakage detection device I is provided in one or both of the carriage side take-up device TU1 and the counterweight side take-up device TU2.

(Carriage side chain end of the suspension chain)
As shown in the partial vertical sectional left side view of Fig. 6 and the partial vertical sectional front view of Fig. 7, a chain end fitting 14 of the chain end 2A on the carriage C side of the hanging chain 2 is connected to a chain end fitting 18 of the chain end 4A on the carriage C side of the driving chain 4. A stopper member 15 is provided on the chain end fitting 14 of the hanging chain 2. The stopper member 15 provided on the chain end fitting 14 is cylindrical and has a coil spring 17 installed inside. The stopper member 15 may also be provided on the chain end fitting 18 of the driving chain 4.

In the state shown in the partial vertical cross-sectional left side view of Figure 6, the upper surface 15A of the stopper member 15 abuts against the abutment surface 16A of the plate 16 provided on the carriage C. In this state, the carriage C is supported and positioned in the height direction by the chain end fitting 14 of the chain end 2A on the carriage C side of the hanging chain 2.

The carriage C can move upward relative to the stopper member 15 from a state in which it is positioned on the chain end fitting 14 as shown in the partial vertical sectional left side view of FIG. 6 to a state in which it is positioned in the partial vertical sectional left side view of FIG. 8.

The structure of the chain end 2A on the carriage C side of the hanging chain 2 as shown in Figures 6 to 8 simplifies the structure of the carriage C and the stopper member 15 at the chain end in the article lifting device 1, which positions the carriage C in the vertical direction by stopping it by placing its load on each floor using a level lock device described below, compared to when the drive chain 4 is directly connected to the carriage C.

(Suspension chain breakage detection device)
6 to 8, a chain breakage detection device J, for example a limit switch, is provided to detect breakage of the hanging chain 2. When the hanging chain 2 breaks, the tip of the lever of the limit switch comes off the outer periphery of the stopper member 15 and the lever rotates, so that the breakage of the hanging chain 2 can be detected.

<Operation of the take-up device>

(No load on the carriage)
As shown in the schematic front view of Figure 9, when no load W is loaded on the carriage C, the counterweight CW is heavier than the weight of the carriage C, so tension equivalent to the unbalance is generated in the drive chain 4 on the carriage C side. This causes the take-up sprocket 8 of the carriage-side take-up device TU1 to move downward. The downward movement of the take-up sprocket 8 is restricted at a predetermined position by the take-up stopper S (the lower end surface 12A of the support cylinder 12 in Figures 4 and 5 abutting against the take-up frame F), so it is possible to resist the tension (tensile force) of the drive chain 4.

The drive chain 4 on the counterweight CW side becomes loose due to wear and elastic elongation of the entire length of the hanging chain 2 and drive chain 4, but tension is applied to the drive chain 4 by moving the take-up sprocket 9 upward due to the upward biasing force of the coil spring 13 of the counterweight side take-up device TU2.

(Carriage loaded with cargo)
As shown in the schematic front view of Figure 10, when a load W is loaded on the carriage C, the weight of the carriage C and the load W is heavier than the weight of the counterweight CW, so tension due to the imbalance is generated in the drive chain 4 on the counterweight CW side. This causes the take-up sprocket 9 of the counterweight-side take-up device TU2 to move downward. The downward movement of the take-up sprocket 9 is restricted at a predetermined position by the take-up stopper S (the lower end surface 12A of the support cylinder 12 in Figures 4 and 5 abutting against the take-up frame F), so it is possible to resist the tension (tensile force) of the drive chain 4.

The drive chain 4 on the carriage C side becomes loose due to wear and elastic elongation of the entire length of the hanging chain 2 and drive chain 4, but tension is applied to the drive chain 4 by moving the take-up sprocket 8 upward due to the upward biasing force of the coil spring 13 of the carriage side take-up device TU1.

As described above, by providing the carriage side take-up device TU1 on the drive chain 4 between the drive sprocket 5 and the carriage C, and providing the counterweight side take-up device TU2 on the drive chain 4 between the drive sprocket 5 and the counterweight CW, the weight Wcw of the counterweight CW can be increased (Wcw≧Wc), and the weight Wcw of the counterweight CW can be made the same as that of an upper drive type goods lifting device (Wcw=Wc+Ww/2), for example. As a result, the unbalanced load, which is the difference in weight between the carriage C side and the counterweight CW side, becomes the same when there is a load W and when there is no load W, so the capacity of the drive device D can be reduced.

(The carriage stops at each floor to adjust the level.)
11 shows an example of a state in which the carriage C stops at each floor, the level is adjusted by a level lock device (not shown), and the weight of the carriage C is placed on the structure of the article lifting device 1. In this example, the level of the carriage C is adjusted to the floor level L of the top floor.

Level adjustment using the level lock device is performed as follows. That is, the level lock device adjusts the level when a carriage lift position sensor (not shown) installed on the carriage C side detects the stopping position of the carriage C, but the drive device D (Figs. 1 to 3) is not stopped immediately, but is operated for an additional predetermined time to lower the drive device D before being stopped.

When the carriage C is ascending or descending, the suspension chains 2, 3 are stretched (elastically stretched) by several tens of millimeters due to the weight of the carriage C and the counterweight CW. When the carriage C is stopped at each floor and the level is adjusted using the level lock device, the load of the carriage C is completely transferred to the structure of the goods lifting device 1 by the level lock device, and the carriage C is completely separated from the suspension chains 2, 3.

In this state where the level has been adjusted by the level lock device, as shown in FIG. 8, the upper surface 15A of the stopper member 15 attached to the chain end fitting 14 of the hanging chain 2 is separated from the abutment surface 16A of the plate 16 attached to the carriage C, and a gap is created between the upper surface 15A of the stopper member 15 and the abutment surface 16A of the plate 16 attached to the carriage C. As a result, the carriage C is separated from the hanging chains 2 and 3, and the carriage C is reliably positioned at the height of each floor by the level lock device.

In Figure 11, the weight of the carriage C is not acting on the hanging chains 2 and 3, so the weight of the counterweight CW causes the hanging chain 2 above the counterweight CW and the section of the drive chain 4 from the carriage C side chain end 4A to the drive sprocket 5 to be in a tensed state. This causes the take-up sprocket 8 of the carriage side take-up device TU1 to move downward. The downward movement of the take-up sprocket 8 is restricted at a predetermined position by the take-up stopper S (the lower end surface 12A of the support tube 12 in Figures 4 and 5 abutting against the take-up frame F), so it can resist the tension (tensile force) of the drive chain 4.

The portion of the drive chain 4 from the chain end 4B on the counterweight CW side to the drive sprocket 5 is in a relaxed state, but the upward biasing force of the coil spring 13 of the counterweight side take-up device TU2 causes the take-up sprocket 9 to move upward, applying tension to the portion of the drive chain 4 from the chain end 4B on the counterweight CW side to the drive sprocket 5.

The above description of the embodiments is merely illustrative and is not intended to be limiting. Various improvements and modifications may be made without departing from the scope of the present invention.

Reference Signs List 1: Article lifting device 2, 3: Suspension chain 2A, 2B, 3A, 3B: Chain end 4: Drive chain 4A, 4B: Chain end 5: Drive sprocket 6A, 6B, 6C: Upper driven sprocket 7A, 7B, 7C: Lower driven sprocket 8, 9: Take-up sprocket 8A, 9A: Support shaft 10: Support frame
1 1 Connecting shaft 12 Support tube 12A End surface 13 Coil spring 14 Chain end fitting 15 Stopper member 15A Top surface 16 Plate 16A Contact surface 17 Coil spring 18 Chain end fitting A Shelf equipment B Item storage space C Carriage CW Counterweight D Drive device E Circular member F Take-up frame G Guide member H Guide pillar I, J Chain breakage detection device K Double nut L Top floor floor level S Take-up stopper SK Gap TU1 Carriage side take-up device TU2 Counterweight side take-up device W Item (load) to be placed on the carriage
Wc Weight of carriage Wcw Weight of counterweight Ww Weight of cargo

Claims (5)

In an article lifting device that lifts and lowers an article on a carriage,
The carriage and the counterweight are suspended in a suspending manner by a suspending chain that engages with an upper driven sprocket disposed on an upper portion of the article lifting device;
One end of a drive chain that engages with a drive sprocket arranged at a lower portion of the article lifting device is connected to a lower end of the carriage or a lower end of the suspension chain that suspends the carriage;
The other end of the drive chain is connected to the counterweight,
An article lifting device that lifts and lowers the carriage and the counterweight along a guide column by driving the drive sprocket with a drive device,
the drive chain between the drive sprocket and the carriage;
A take-up device is provided on the carriage side,
the drive chain between the drive sprocket and the counterweight;
A counterweight side take-up device is provided ,
The carriage side take-up device and the counterweight side take-up device are
a take-up sprocket that engages with the drive chain and is movable in a direction to apply tension to the drive chain and in a direction opposite thereto;
a biasing member that biases the take-up sprocket in a direction that applies tension to the drive chain; and
a take-up stopper that restricts the movement of the take-up sprocket in a direction against the biasing force of the biasing member at a predetermined position;
Equipped with
Goods lifting device. a first lower driven sprocket is provided at a lower end of the drive chain that depends from the carriage, and a second lower driven sprocket is provided at a lower end of the drive chain that depends from the counterweight;
The drive sprocket is disposed between the drive chain that is suspended from the carriage and redirected by the first lower driven sprocket and the drive chain that is suspended from the counterweight and redirected by the second lower driven sprocket;
the carriage side take-up device is provided on the drive chain between the first lower driven sprocket and the drive sprocket;
The counterweight side take-up device is provided on the drive chain between the second lower driven sprocket and the drive sprocket.
An article lifting device as claimed in claim 1. The weight of the counterweight is equal to or greater than the weight of the carriage.
An article lifting device according to claim 1 or 2 . a chain breakage detection device for detecting breakage of the drive chain is provided in one or both of the carriage side take-up device and the counterweight side take-up device;
An article lifting device according to any one of claims 1 to 3 . a chain end of the driving chain on the carriage side is connected to a chain end of the suspension chain on the carriage side;
the carriage is positioned relative to the carriage-side chain end of the suspension chain and the carriage-side chain end of the drive chain in a state in which the carriage abuts against a stopper member provided at the carriage-side chain end of the suspension chain or the carriage-side chain end of the drive chain,
The carriage is movable upward relative to the stopper member.
An article lifting device according to any one of claims 1 to 4 .

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