JP3672291B2 - Stacker crane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stacker crane for transferring workpieces between a storage shelf of a three-dimensional warehouse and a loading / unloading device, and more particularly, when the take-up drum is brought to an emergency stop while the carriage is being raised at a high speed. It prevents the excessive tension from being applied to the cable body that suspends the cable.
[0002]
[Prior art]
Conventionally, an example of this type of stacker crane is shown in FIG. The pair of cords 1, 2 are wound around the take-up drum 3, and one end of each cord 1, 2 is connected to the carriage 6 via the lower sheave 4 and the upper sheave 5, The other ends of the cords 1, 2 are connected to the counterweight 9 via the lower sheave 7 and the upper sheave 8, and the cords 1, 2 are rotated by rotating the winding drum 3 forward and backward. The carriage 6 is moved up and down via the. Reference numeral 10 denotes a slide fork disposed on the carriage 6 on which the work W is placed.
[0003]
[Problems to be solved by the invention]
In the above-described conventional configuration, since the entire weight of the carriage 6 is applied to the winding drum 3, the winding drum 3 is emergency-stopped while the winding drum 3 is rotationally driven to raise the carriage 6 at a high speed. However, there is an advantage that the carriage 6 hardly floats due to inertia and there is no fear that an excessive tension is applied to each of the ropes 1 and 2, but the cost of the ropes 1 and 2 is increased. There is a drawback of becoming.
[0004]
In order to eliminate the above drawbacks, as shown in FIG. 7, the leading ends of the cords 1 and 2 wound around the winding drum 3 are connected to the carriage 6 through a pair of upper and lower sheaves 12 and 13, and A counterweight 9 for canceling the weight of the carriage 6 is connected between the upper and lower sheaves 12, 13 of the bodies 1, 2, and the winding drum 3 is rotated forward and backward so It is considered to raise and lower the carriage 6.
[0005]
According to the above configuration, there is an advantage that each cord body 1 and 2 can be shortened to reduce the cost. However, since the weight of the carriage 6 is reduced by the counterweight 9 and rests on the winding drum 3. If the take-up drum 3 is brought to an emergency stop while the carriage 6 is being raised at a high speed, the carriage 6 once floats due to inertia and falls.
[0006]
Here, assuming that the weight of the carriage 6 is 600 kg, the weight of the counterweight 9 is 300 kg, and the winding speed of each of the ropes 1 and 2 is 80 m / mm, the carriage 6 is dropped after being lifted by about 0.26 m by approximate calculation. Then, excessive tension is applied to each of the cords 1 and 2 in a shocking manner, and the cords 1 and 2 may be broken.
[0007]
SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a stacker crane that prevents excessive tension from being applied to a cable body that suspends the carriage when the take-up drum is stopped in an emergency while the carriage is being raised at a high speed. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a pair of front and rear masts are erected on a carriage, and a workpiece loading / unloading carriage is disposed between the masts so that the carriage can be raised and lowered. The tip of the cable body pulled out from the take-up drum is connected to the carriage via sheaves provided at the upper and lower ends of each mast, and a counterweight for canceling the weight of the carriage is connected between the upper and lower sheaves of the cable body. In a stacker crane that moves the carriage up and down by rotating the winding drum forward and backward, a rotation lever with a roller that is rotatably supported by the carriage, A tension device having pressing means for pressing the roller against the cable body via the rotating lever is provided between the winding drum and the counterweight. Are, the pressing means has a hydraulic cylinder the ends coupled to the tip and carriage of the auxiliary arm, and a spring biasing the piston of the hydraulic cylinder extending direction, of the hydraulic cylinder cylinder A check valve and a throttle valve are disposed in parallel in a hydraulic circuit that communicates the extension side chamber and the reduction side chamber provided in the body, and pressure oil is supplied from the reduction side chamber to the extension side chamber through the check valve. At the same time, it is characterized in that pressure oil is supplied from the expansion side chamber to the reduction side chamber through the throttle valve .
[0009]
According to the above configuration, the roller is pressed against the cable body that suspends the carriage by the pressing unit of the tension device via the rotation lever, so that the winding drum is stopped in an emergency while the carriage is being raised at high speed. As a result, when the carriage is lifted by inertia and the cord body is slackened, the roller is moved by the amount of the slack and pressed against the cord body, and the slackness of the cord body is absorbed. Therefore, once the carriage is lifted by inertia, it is supported by the pressing means and does not fall, and it is possible to prevent an accident that the cable body is excessively tensioned and the cable body is broken as in the prior art. it can.
[0010]
In the invention of claim 1, the pressing means includes a hydraulic cylinder having both ends connected to the tip of the auxiliary arm and the carriage, and a spring that biases the piston of the hydraulic cylinder in the extending direction, A check valve and a throttle valve are interposed in parallel in a hydraulic circuit that communicates the extension side chamber and the reduction side chamber provided in the cylinder body of the hydraulic cylinder, and pressure is applied from the reduction side chamber to the extension side chamber through the check valve. A feature is that oil is supplied and pressure oil is supplied from the extension side chamber to the reduction side chamber through the throttle valve.
[0011]
According to the above configuration, the pressing means has the hydraulic cylinder and the spring that urges the piston of the hydraulic cylinder in the extending direction, and makes the winding drum perform an emergency stop while raising the carriage at a high speed. When the carriage is lifted by inertia and the cable body is slackened, the piston is rapidly moved in the extending direction by the spring, and the pressure oil is supplied from the reducing side chamber of the cylinder body to the extending side chamber. It moves and is pressed against the cord, and the slack of the cord is absorbed. Next, once the carriage that has lifted up due to inertia begins to fall, the spring is compressed by the piston, and the pressure oil in the expansion side chamber of the cylinder body is supplied to the reduction side chamber via the throttle valve, so that the roller returns to its original position. Accordingly, the accident that the carriage falls and the cable body is broken as in the prior art can be prevented.
[0012]
According to a second aspect of the present invention, in the first aspect of the present invention, the rotating lever includes a long lever main body, and a base end of the lever main body in a direction orthogonal to the longitudinal direction of the lever main body. The base end portion of the lever body is rotatably supported by the carriage via a support shaft, and the tip end portion of the lever body is A roller is rotatably attached, and the pressing means is connected to the tip of the auxiliary arm.
[0013]
According to the above configuration, the length of the auxiliary arm is shorter than the length of the lever body, and the rotation stroke of the auxiliary arm is enlarged by the lever body and transmitted to the roller attached to the tip of the lever body. Therefore, it is possible to use a small pressing means for rotating the auxiliary arm, the manufacturing cost is low, and the reduced pressing means can be easily incorporated in a narrow space on the carriage. Can do.
[0014]
According to a third aspect of the present invention, in the first or second aspect of the invention, a guide frame having substantially the same width as the roller is attached to the rotating lever, and a rope is inserted into the guide frame. It is characterized by having.
[0015]
According to the said structure, a rope can be prevented from removing from a roller with a guide frame.
[0016]
A fourth aspect of the invention is characterized in that, in the invention according to any one of the first to third aspects, a slack detecting device for detecting slack of the cord body is provided.
[0017]
According to the above configuration, the take-up drum is brought to an emergency stop while the carriage is being raised at high speed, so that the carriage is caught on the receiving shelf of the storage shelf as well as when the carriage is lifted by inertia and the cable body is slackened. In the state where the carriage is in contact with the workpiece stored below, the carriage continues to descend, and when the cable body is slackened, the slackness is detected by the slackness detecting device. It is possible to immediately detect a descending abnormality of the.
[0018]
According to a fifth aspect of the present invention, in the fourth aspect of the invention, the slack detecting device includes a light projector and a light receiver that are opposed to each other with a rotation lever interposed therebetween.
[0019]
According to the said structure, the slack of a cord can be reliably detected with a light projector and a light receiver using a rotation lever.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a stacker crane according to an embodiment of the present invention, the basic structure of which is the same as that shown in FIG. 7, and is arranged along a storage shelf (not shown) of a three-dimensional warehouse. A carriage 17 that is guided and moved by a pair of upper and lower guide rails 15 and 16 is provided. A pair of rotation levers 18b with rollers 18a supported rotatably on the carriage 17 and the respective rotation levers 18b. A tension device 18 having a pair of pressing means 18c for pressing the rollers 18a against the cords 1 and 2 and a slack detection device 19 for detecting slack of the cords 1 and 2 are provided. A pair of front and rear square cylindrical masts 20, 21 are erected on the carriage 17, and a winding drum 3 that is rotationally driven by a drive motor 22 is provided on one side of the mast 20. The carriage 6 is disposed between the masts 20 and 21 so that the sheaves 12 and 13 are rotatably provided. The counterweight 9 is inserted into the masts 20 and 21 so as to be movable up and down. .
[0021]
In the above configuration, when the work W is carried into the storage shelf, the carriage 17 is moved to a predetermined position, and then the winding drum 3 is rotated by the drive motor 22 so that each of the ropes 1 and 2 is interposed. When the carriage 6 is raised to a predetermined height (see the phantom line in FIG. 1), the slide fork 10 on the carriage 6 is moved horizontally, and the work W on the slide fork 10 is carried into a predetermined section of the storage shelf. Good. Moreover, what is necessary is just to perform in the reverse procedure to the above, when carrying out the workpiece | work W from a storage shelf.
[0022]
2 to 4, the rotating levers 18b are long levers disposed on both side surfaces of a vertical plate 23b fixed to the lower end portion of the winding drum 3 side mast 20 via a cross beam 23a. The main body 24a and a short auxiliary arm 24b extending substantially along the direction orthogonal to the longitudinal direction of the lever main body 24a from the base end portion of the lever main body 24a are formed in a substantially L shape. The base end portion is supported by the vertical plate 23b via the support shaft 25 so as to be rotatable in the directions of arrows a and b, and the roller 18a is rotatably attached to the distal end portion of the lever main body 24a. The pressing means 18c is connected to the front end portion.
[0023]
According to the above configuration, the length h of the auxiliary arm 24b is shorter than the length H of the lever main body 24a, and the rotation stroke L of the auxiliary arm 24b is enlarged by the lever main body 24a and transmitted to the roller 18a. Therefore, a small pressing means 18c for rotating the auxiliary arm 24b can be used, and the manufacturing cost is low, and the reduced pressing means 18c can be easily placed in a narrow space on the carriage 17. Can be incorporated.
[0024]
As shown in FIGS. 2, 3 and 5, the pressing means 18c has a hydraulic cylinder 27. The cylinder body 27a of the hydraulic cylinder 27 is connected to the vertical plate 23b via a connecting pin 28. The piston rod 27b of the hydraulic cylinder 27 is connected to the tip of the auxiliary arm 24b via a connecting pin 29, and a spring 30 for urging the piston 27c in the extending direction is disposed in the extending side chamber 31 in the cylinder body 27a. A check valve 34 and a throttle valve 35 are disposed in parallel in a hydraulic circuit 33 that allows the extension side chamber 31 and the reduction side chamber 32 in the main body 27a to communicate with each other. The extension side chamber 31 passes from the reduction side chamber 32 through the check valve 34. The pressure oil is supplied from the extension side chamber 31 to the reduction side chamber 32 through the throttle valve 35.
[0025]
In the above-described configuration, when the work W is being carried in and out, the rollers 18a of the tension device 18 are pressed against the cords 1 and 2, and the winding drum is in the middle of raising the carriage 6 at a high speed. When the carriage 6 is lifted by inertia and the cords 1 and 2 are slackened by emergency stop, the piston 27b is rapidly moved in the extending direction by the spring 30, and the expansion side chamber is moved from the reduction side chamber 32 of the cylinder body 27a. Pressure oil is supplied to 31, thereby causing the piston rod 27 b to rapidly extend and move (see the phantom line in FIG. 5), and the rotation lever 18 b is rotated about the support shaft 25 in the direction of arrow a. The roller 18a moves by the amount of the slack of the bodies 1 and 2 and is pressed against each of the cords 1 and 2, and the slack of the cords 1 and 2 is absorbed (see the phantom line in FIG. 2).
[0026]
Next, once the carriage 6 lifted by inertia starts to fall, the spring 30 is compressed by the piston 27c, and the pressure oil in the expansion side chamber 31 of the cylinder body 27a is gradually supplied to the reduction side chamber 32 via the throttle valve 35. As a result, the piston rod 27b is reduced and moved at a low speed, the rotation lever 18b is rotated about the support shaft 25 in the direction of the arrow b, and the roller 18a is gradually returned to the original position. Therefore, it is possible to prevent an accident that the carriage 6 is dropped and the cords 1 and 2 are broken as in the prior art.
[0027]
As shown in FIG. 3 and FIG. 4, a substantially U-shaped guide frame 37 having the same width as that of the roller 18a is attached to each of the rotating levers 18b. Is inserted so that the cords 1 and 2 are not detached from the roller 18a.
[0028]
As shown in FIGS. 2 and 4, the slack detecting device 19 is attached to a substantially L-shaped support frame 39 fixed to the upper cross beam 23a and faces each other through the through hole 40 of the vertical plate 23b. And a light receiver 19b.
[0029]
In the above configuration, as described above, not only is the case where the take-up drum 3 is brought to an emergency stop while the carriage 6 is being raised at a high speed, so that the carriage 6 is lifted by inertia and the cords 1 and 2 are slackened. When the carriage 6 is hooked on the receiving shelf of the storage shelf or the carriage 6 is in contact with the workpiece W stored below, the lowering operation of the carriage 6 continues, so When loosened, the rotating lever 18b is rotated in the direction of arrow a, and the projection light from the light projector 19a to the light receiver 19b is blocked by the auxiliary arm 24b of the rotating lever 18b (see the phantom line in FIG. 2). As a result, the slack of the cords 1 and 2 can be detected, and the lowering abnormality of the carriage 6 can be immediately detected.
[0030]
In the above embodiment, the hydraulic cylinder 27 incorporating the spring 30 is used as the pressing means 18c. However, the present invention is not limited to this, and the spring 30 may be provided outside the cylinder body 27a. Alternatively, the hydraulic cylinder 27 may be omitted and the rotating lever 18b may be urged in the direction of the arrow a by only the spring 30.
[0031]
【The invention's effect】
According to the first aspect of the present invention, since the roller is pressed against the cable body that suspends the carriage by the pressing means of the tension device via the rotation lever, the winding is performed while the carriage is being raised at high speed. If the carriage is lifted by inertia and the cable body is loosened by the emergency stop of the drum, the roller moves and is pressed against the cable body by the loose amount, and the slack of the cable body is absorbed. Therefore, once the carriage is lifted by inertia, it is supported by the pressing means and does not fall, and it is possible to prevent an accident that the cable body is excessively tensioned and the cable body is broken as in the prior art. it can.
[0032]
According to the first aspect of the present invention, the pressing means has a hydraulic cylinder and a spring for urging the piston of the hydraulic cylinder in the extending direction, and the winding drum is moved while the carriage is raised at high speed. When the carriage is lifted by inertia and the cable body is slackened by the emergency stop, the piston is rapidly moved in the extending direction by the spring, and the pressure oil is supplied from the reducing side chamber of the cylinder body to the extending side chamber. The roller moves so much that it is pressed against the cable body, and the slack of the cable body is absorbed. Next, once the carriage that has lifted up due to inertia begins to fall, the spring is compressed by the piston, and the pressure oil in the expansion side chamber of the cylinder body is supplied to the reduction side chamber via the throttle valve, so that the roller returns to its original position. Accordingly, the accident that the carriage falls and the cable body is broken as in the prior art can be prevented.
[0033]
According to the second aspect of the present invention, the length of the auxiliary arm is shorter than the length of the lever main body, and the rotation stroke of the auxiliary arm is enlarged by the lever main body and attached to the tip of the lever main body. Therefore, it is possible to use a small pressing means for rotating the auxiliary arm, and the manufacturing cost is low and the reduced pressing means is placed in a narrow space on the carriage. Can be easily incorporated.
[0034]
According to the invention described in claim 3, it is possible to prevent the cable body from being detached from the roller by the guide frame.
[0035]
According to the fourth aspect of the present invention , not only when the carriage is lifted by inertia and the cable body is slackened by the emergency stop of the winding drum while the carriage is being raised at a high speed, the carriage is mounted on the storage shelf. If the cable body is slackened by being caught on a receiving shelf or in a state where the carriage is in contact with the workpiece stored below, the slack is detected by the slack detecting device. Thus, it is possible to immediately detect an abnormality in the lowering of the carriage.
[0036]
According to the fifth aspect of the present invention, the slack of the cable body can be reliably detected by the light projector and the light receiver using the rotating lever.
[Brief description of the drawings]
FIG. 1 is a side view of a stacker crane according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of the main part.
FIG. 3 is a front view of the main part.
FIG. 4 is a horizontal sectional view of the main part.
FIG. 5 is a schematic longitudinal sectional view of the pressing means.
FIG. 6 is a schematic view showing an example of the prior art.
FIG. 7 is a schematic view showing another conventional example.
[Explanation of symbols]
1, 2 Rope 3 Winding drum 6 Carriage 12, 13 Sheave 17 Cart 18 Tension device 18a Roller 18b Rotating lever 18c Pushing means 19 Loosening detection device 19a Light projector 19b Light receiver 20, 21 Mast 24a Lever body 24b Auxiliary arm 27 Hydraulic pressure Cylinder 27a Cylinder body 27c Piston 30 Spring 31 Expansion side chamber 32 Reduction side chamber 33 Hydraulic circuit 34 Check valve 35 Throttle valve

Claims (5)

A pair of front and rear masts are erected on the carriage, and a workpiece loading / unloading carriage is disposed between the masts so that the carriage can be moved up and down. A counterweight for canceling the weight of the carriage is connected between the upper and lower sheaves of the rope body, and by rotating the winding drum forward and backward, In a stacker crane configured to raise and lower the carriage via the rope, a rotation lever with a roller supported rotatably on the carriage, and the roller is pressed against the rope via the rotation lever tensioning device having a pressing means, said provided between the winding drum and the counterweight, the pressing means, both ends of the auxiliary arm A hydraulic cylinder having a hydraulic cylinder connected to the end and the carriage, and a spring that biases the piston of the hydraulic cylinder in the extending direction, and communicates an extension side chamber and a reduction side chamber provided in the cylinder body of the hydraulic cylinder. A check valve and a throttle valve are arranged in parallel in the circuit, and pressure oil is supplied from the reduction side chamber to the extension side chamber through the check valve, and from the extension side chamber to the reduction side chamber through the throttle valve. The stacker crane is configured to be supplied .   The rotating lever is formed in a substantially L shape by a long lever body and a short auxiliary arm extending substantially along a direction orthogonal to the longitudinal direction of the lever body from a base end portion of the lever body. A base end portion of the lever main body is rotatably supported by the carriage via a support shaft, and the roller is rotatably attached to a tip end portion of the lever main body, and the tip end portion of the auxiliary arm is The stacker crane according to claim 1, wherein the pressing means is connected. 3. The stacker according to claim 1 , wherein a guide frame having substantially the same width as that of the roller is attached to the rotating lever, and a rope is inserted into the guide frame. crane. The stacker crane according to any one of claims 1 to 3 , further comprising a slack detecting device that detects slack of the cord. The stacker crane according to claim 4 , wherein the slack detecting device includes a light projector and a light receiver that are opposed to each other with a rotation lever interposed therebetween.

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