JP4873262B2 - Stacker crane - Google Patents

Description

  The present invention relates to a stacker crane, and more particularly to detecting the size of an item to be loaded.

  A stacker crane for conveying pallets of different sizes is known (for example, Patent Document 1: Japanese Patent Laid-Open No. 5-208708). When loading a pallet, the extension amount of the transfer means is shortened for a small pallet, and the extension amount is increased for a large pallet. Here, if a large pallet is mistaken for a small pallet, the extension amount is short, and thus there is a possibility that the large pallet cannot be supported by the transfer means.

Therefore, in Patent Document 1, an optical sensor is provided at the tip of the slide fork to monitor the pallet. Apart from this, a length sensor composed of a phototube or the like is provided on the slide fork to detect the size of the pallet. However, when an optical sensor is provided at the tip of the slide fork, it is necessary to provide a cable bear (registered trademark) or the like inside the slide fork. If a plurality of photoelectric sensors are arranged in parallel to form a length sensor, the structure becomes complicated.
JP 5-208708

  It is an object of the present invention to reliably detect the size of an article, reliably detect whether the extension amount of the slide fork matches the size of the article, and simplify the wiring in the slide fork. There is.

  The present invention includes a carriage, a mast, a lift, and at least two types of articles having different bottom shapes, and at least a base portion fixed to the lift and a top portion that moves forward and backward with respect to the base portion. In the stacker crane provided with a slide fork, a protruding member that protrudes from the height position of the top surface of the top portion so as to be freely retractable and a detected member whose position changes due to the protruding and retracting of the protruding member. The base member is provided with a sensor for selectively operating the member to be detected due to a difference in bottom shape of the at least two kinds of articles and detecting the position of the member to be detected. Features.

In this case, since the member to be detected selectively operates depending on the difference in the shape of the bottom of the article, the type of the article can be easily detected, and whether or not the extension amount of the slide fork and the size of the article match each other can be easily detected. Can be detected. Further, since there is no need to perform wiring from the protruding member or the member to be detected to the base side, there is no need to provide a cable bear (registered trademark) or the like on the top portion.

Preferably, the sensor is a photoelectric sensor,
When the protruding member moves backward from the height position of the top surface of the top portion and the position of the detected member changes, a reflector is provided on the top portion so as to be blocked by the detected member,
The at least two kinds of articles are a large article and a small article,
The protruding member selectively comes into contact with the bottom of a large article and moves backward to move the member to be detected from a position where the reflecting plate is not blocked with respect to the photoelectric sensor.
In this way, when picking up large articles, the reflector will be blocked and the photoelectric sensor will not be able to detect the reflected wave, and even if there is a failure in the sensor, the signal from the photoelectric sensor will be the same. Since it is judged as a large article, it becomes fail-safe.

Preferably, the slide fork is stretched with a relatively large stroke to load one of the at least two kinds of articles, and is stretched with a relatively small stroke to obtain the at least two kinds of articles. The other is configured to scoop the other, and after extending the slide fork with the relatively small stroke, the slide fork is raised, and the position of the detected member is detected by the sensor, and the detected When the position of the member is abnormal, a control means is provided for stopping the slide fork from rising.
In this way, the type of the article can be reliably detected before the article is actually loaded.

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  The stacker crane 2 of an Example is shown in FIGS. In each figure, 4 is a cart, which has a pair of masts 5, 5, for example, and travels along a travel rail 7. The elevator 8 is raised and lowered along the masts 5 and 5, and the slide fork 10 is supported by the elevator 8. The slide fork 10 has a base portion 12 fixed to the lifting platform 8, a middle portion 14 that slides in the left-right direction in FIG. 1 with respect to the base portion 12, and a left-right direction in FIG. And a top portion 16. The control unit 18 controls the stacker crane 2 and particularly controls the operation of the slide fork 10.

  For example, shelves 20 and 20 are provided on the left and right sides of the traveling rail 7, and 21 is a pillar for supporting the pallets 22 to 24 by a shelf holder 25. The pallet 22 is a large pallet, and the pallets 23 and 24 are small pallets having the same structure. When delivering the large pallet 22, the slide fork 10 extends the top portion 16 by the full stroke, and when delivering the small pallet 23 near the stacker crane 2 of the shelves 20, 20, the slide fork 10 moves the top portion 16 by half stroke. Stretch. When delivering a pair of small pallets 23 and 24 arranged in the depth direction, the top portion 16 is extended by a full stroke as in the case of the large pallet 22.

  2 to 4 show the structure of the slide fork 10. For example, there are a pair of photoelectric sensors 30 at both the left and right ends of the base portion 12, and an ultrasonic sensor or the like may be used as long as it is a reflective position sensor. In this specification, the left and right are the forward and backward directions of the slide fork 10. A pair of switches 28 and 28 are provided near the center of the top portion 16, for example, symmetrically with respect to the center of the top portion 16. The switch 28 includes a protruding portion 31 protruding to a height position higher than the upper surface of the top portion 16, a shaft 32 that rotates the protruding portion 31, and a detected member 34 that rotates together with the protruding portion 31. Reference numeral 36 denotes a reflection plate, which is covered by the detection member 34 when the projecting portion 31 rotates and does not reflect the light from the photoelectric sensor 30. When the projecting portion 31 is not rotated, the reflected light is transmitted to the optical sensor 30. return. The optical sensor 30 detects the position of the detected member 34 from the presence or absence of reflected light. The member 34 to be detected is urged by the urging member 35 toward a position where the reflecting plate 36 is not covered, and 38 is a housing of the switch 28. Further, the protruding portion 31 may be freely raised and lowered instead of rotating about the shaft 32, and the biasing member 35 may be any member that biases the protruding portion 31 in a direction protruding from the height of the upper surface of the top portion 16. Good. Further, the switch 28 may be provided inside the top portion 16 or may be provided on the side portion of the top 16 as shown in FIG.

  FIG. 5 shows the bottom shape of the large pallet 22 and the bottom shape of the small pallet 23, and the bottom shape of the small pallet 24 is the same as that of the small pallet 23. The pallets 22 and 23 are respectively provided with ridges 41 to 43 and 51 to 53 parallel to the depth direction at the bottom, and concave portions 45 and 55 are provided between the ridges. The slide fork 10 delivers, for example, by supporting the protrusions 42 and 42 and the protrusions 52 and 52 with the top portion 16. And the protrusion 42 of the large pallet 22 is wider than the protrusion 52 of the small pallet 23, and the protrusion 31 is pressed downward by the protrusion 42, but does not contact the protrusion 52.

  FIG. 6 shows an algorithm for picking up the small pallet 23. The slide fork 10 is moved forward by a half stroke, and the slide fork is slightly lifted together with the lift 8 from here. Here, when the slide fork 10 comes into contact with the small pallet 23, the protruding portion 31 does not come into contact with the protrusion 52, so that the photoelectric sensor 30 receives the reflected light from the reflecting plate 36. On the other hand, when the slide fork is in contact with the large pallet 22, the protrusion 31 is rotated by the protrusion 42, the reflection plate 36 is covered by the detection member 34, and the photoelectric sensor 30 does not receive the reflected light. . In addition to this, a normal light reception signal cannot be obtained even if the reflecting plate 36 is dirty or the photoelectric sensor 30 is defective.

  Therefore, if a normal light reception signal cannot be obtained, the loading operation is stopped, for example, the elevator is slightly lowered to wait for maintenance. When the photoelectric sensor 30 receives the reflected light from the reflecting plate 36, it can be confirmed that the pallet is a small pallet. Therefore, the slide fork is further raised, and the small pallet is transferred from the shelf holder 25 onto the top portion 16. Then, the top portion 16 is moved backward to complete the loading.

  When the object to be loaded is the large pallet 22 or the small pallet 24, the slide fork 10 expands by the full stroke, so that there is no problem that the expansion amount is insufficient. Further, when unloading the pallets 22 to 24 onto the shelf support 25, the type of pallet is known to the control unit 18 of the stacker crane 2, so it is not necessary to confirm the type of pallet with the switch 28.

In the embodiment, the following effects can be obtained.
(1) The type of pallet can be easily detected by the combination of the switch 28 and the photoelectric sensor 30, and the small pallet 23 and the large pallet 22 are not mistaken.
(2) If the photoelectric sensor 30 is defective, the switch 28 is defective, or the reflector 36 is dirty, a normal light reception signal cannot be obtained.
(3) There is no need to perform wiring between the switch 28 and the base portion 12, and a cable bear (registered trademark) or the like is not required.
(4) When the switch 28 is provided on the side portion of the top portion 16, the switch 28 can be easily attached.
(5) When the switch 28 is arranged so as to be positioned on the front side of the small pallet 23 when the top portion 16 is extended by a half stroke, the interval between the photoelectric sensor 30 and the switch 28 can be shortened, and the detection becomes easy. .

In the embodiment, the detection of the size of the pallet is taken as an example. However, the detection can be similarly performed by detecting the bucket or the like. The photoelectric sensor 30 and the switch 28 may be provided only on the left or right side of the slide fork 10. Furthermore, instead of detecting the large pallet 22, the switch 28 may be arranged to detect the small pallet 23.

The top view which shows the stacker crane and surrounding shelf of an Example The side view which shows the slide fork which extended the half stroke in the Example. Side view of main part of slide fork Cross section of the main part of the top of the slide fork Bottom view of large and small pallets The flowchart which shows the algorithm at the time of picking up a small pallet in an Example.

Explanation of symbols

2 Stacker crane 4 Carriage 5 Mast 7 Traveling rail 8 Lifting base 10 Slide fork 12 Base part 14 Middle part 16 Top part 18 Control part 20 Shelf 21 Pillar 22 Large pallet 23, 24 Small pallet 25 Shelf holder 28 Switch 30 Photoelectric sensor 31 Projection Portion 32 Shaft 34 Detected member 35 Energizing member 36 Reflecting plate 38 Housings 41 to 43 Projections 51 to 53 Projections 45 and 55 Recess

Claims (3)

A slide fork including a carriage, a mast, a lift, and at least two kinds of articles having different bottom shapes, and at least a base portion fixed to the lift and a top portion that moves forward and backward with respect to the base portion; In stacker cranes with
The top portion is provided with a projecting member projecting freely from a height position of the top surface of the top portion, and a detected member whose position is changed by the projecting and retracting of the projecting member. With the shape difference, the detected member is selectively operated,
A stacker crane, wherein a sensor for detecting a position of the detected member is provided in the base portion. The sensor is a photoelectric sensor,
When the protruding member moves backward from the height position of the top surface of the top portion and the position of the detected member changes, a reflector is provided on the top portion so as to be blocked by the detected member,
The at least two kinds of articles are a large article and a small article,
The projecting member is selectively brought into contact with the bottom of a large article and moved backward to move the member to be detected from a position where the photoelectric sensor is not shielded from a reflecting plate to a position where it is shielded. The stacker crane according to claim 1. The slide fork is stretched with a relatively large stroke to load one of the at least two types of articles, and the slide fork is expanded with a relatively small stroke to load the other of the at least two types of articles. As well as
After extending the slide fork with the relatively small stroke, the slide fork is raised, the position of the detected member is detected by the sensor, and if the position of the detected member is abnormal, The stacker crane according to claim 1 or 2, further comprising a control means for stopping the ascent.

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