KR20080027726A - Transfer system - Google Patents

Abstract

A transfer system is provided to reduce transferring time and a space of a product stand side by reducing a stroke to lift an arm at low speed. A transfer system includes a shelf receiving unit(30) and a slide fork(16). A pair of linear marks(31,32) are formed up and down in parallel with a loading surface of the shelf receiving unit. The slide fork is composed of a base unit, a middle unit(34), and a top unit(35). The base unit of the slide fork is fixed to a lift(2). A pair of image sensors(36,37) are installed at both ends of the top unit. A titling apparatus tilts the lift according to forward and backward movements of the slide fork to correct a gradient of the top unit of the slide fork into zero.

Description

Transport system {TRANSFER SYSTEM}

The present invention relates to a system in which a stacker crane or a overhead traveling car, a tracked trolley, an unmanned transport vehicle, or the like is combined with article racks such as shelves. The invention relates, in particular, to a system adapted to correct the tilt of the conveying device.

When conveying an article with a slide fork or the like, it is known that the slide fork bends by its own weight and load from the article. Therefore, Patent Document 1 proposes correcting the deflection of the slide fork by tilting the lift table on which the slide fork is mounted. In order to perform the correction correctly, it is necessary to accurately detect the deflection of the slide fork. However, in sensors such as strain gauges, acceleration due to forward / retract and vibration of the slide fork becomes an error, and thus it is difficult to accurately detect the warpage.

[Patent Document 1] Japanese Utility Model Publication Hei 7-98l1

An object of the present invention is to enable an article to be conveyed at high speed, space saving, and low impact. A further object of the invention of claim 2 is to enable the transfer device to detect the inclination without waiting for the forwarding / retracting to complete. A further problem in the invention of claim 3 is to make it possible to detect the inclination of the transfer device more accurately.

The present invention provides a conveying apparatus having a forwarding and retracting arm, and a transport system in which goods are transported by the transport device, wherein the transport platform has at least two positions of the article storage surface. The conveying apparatus is formed such that a mark having the same height is formed, a detecting means for detecting a difference between the heights of the at least two marks on the arm of the conveying apparatus, and the difference of the height position determined by the detecting means is eliminated. It characterized in that the tilt means for tilting (tilt) in the forward / backward direction of the arm.

Preferably, the mark consists of a continuous line parallel to the article loading surface. Also preferably, the detection means may comprise at least one pair of optical sensors arranged at intervals along the forward / retract direction of the arm.

(Effects of the Invention)

In the present invention, the arm is advanced toward the article base side to detect the difference in the heights of at least two marks. If the arm is parallel to the article loading surface, there is no difference in the height of the mark seen from the detection side, and if it is not parallel, there is a difference in height in the mark. Thus, by tilting the transfer device to eliminate this difference, the arm can be transferred parallel to the article loading surface. If the arm is parallel to the article loading surface, the impact when receiving the article between the article stage and the arm is reduced. In addition, since the stroke for raising and lowering the arm to the slow speed can be shortened, the transportation time can be shortened and the space on the side of the article can be saved. These can be transported with low impact, high speed and space saving.

By making the mark a continuous line parallel to the article loading surface, the mark can be detected in a wide range of advancing / retracting the arm. When the mark is detected at at least one position, the height is stored, and the change in the height of the mark can then be detected to detect the inclination of the arm. Therefore, the inclination can be detected even if the arm does not advance to the correct position. In the detection of the inclination due to the difference in the height of the mark, the detection accuracy is improved as the interval between positions for detecting the mark is wider. Therefore, if the detection means are arranged at intervals along the arm forward / retract direction, the inclination of the arm can be detected more accurately.

Best Mode for Carrying Out the Invention The following shows an optimal embodiment.

EXAMPLE

1-8, the transfer system of an Example is shown as an example of a stacker crane. In the angular plane, 2 is a lifting platform, for example, it moves up and down along a pair of masts 4 and 4, and there are bogies not shown by a stacker crane at its lower part, and travel on a running rail not shown. Moreover, the trolley | bogie and the lifting motor of the lifting platform 2 are provided in the trolley | bogie. The lifting platform 2 is elevated along the mast 4 by the left and right guide units 6 and 6 and the linear motion guide (LM guide) 7, for example, 8 is an upper frame of the lifting platform 2. The pin 10 is pivotally attached to the guide unit 6 with the pins 10 and 12 as the pivot center.

2, the pin 12 is attached to the guide unit 6 and penetrates through the long hole 18 formed in the upper frame 8 and the tilt mechanism 14. 20 and the linear motion guide 24, the nut 20 is moved left and right along the ball screw 21 by the tilt motor 22. 26 is a guide unit for guiding the linear motion guide 24. When the tilt motor 22 is operated, the upper frame 8 and the tilt mechanism 14 move left and right with respect to the pin 12, and the upper frame 8 cannot move left and right with respect to the pin 10. ) Moves left and right with the pin 10 as a point. As a result, the platform 2 is inclined along the forward / retract direction of the slide fork 16.

3 and 4, 30 is a shelf, which is installed along the shelves of the automatic warehouse on which the stacker crane runs, and the support of the shelf 30 is omitted. In parallel with the longitudinal direction of the shelf 30, in other words, two linear marks 31 and 32 are formed up and down parallel to the article mounting surface of the shelf 30. As shown in FIG. The marks 31 and 32 are optical marks, such as a color tape, for example. The slide fork 16 has a base unit fixed to the platform 2, and includes a middle unit 34 and a top unit 35, and the image sensor 36 is provided near the left and right ends of the top unit 35 at the tip end. 37). The image sensors 36 and 37 are optical sensors having, for example, a vertical direction in the viewing direction, but may be a CCD camera or the like having a planar view.

In Fig. 4, inclination detection of the top unit with respect to the shelf 30 is shown, 40 and 41 represent the field of view of the image sensors 36 and 37 of Fig. 3, for example, two upper and lower marks 31 and 32. If can be recognized, the distances (d1, d2) to the center of view with respect to the average height is obtained. When only one of the marks 31 and 32 can be detected, the height distance between the detected mark and the viewing center may be obtained. When the top unit is horizontal, the differences d1 and d2 between the viewing center and the heights of the marks 31 and 32 are common. The difference between d1 and d2 represents the inclination of the top unit, tilts the platform 2 by the tilt mechanism 14 of FIG. 2, and corrects the inclination of the top unit of the slide fork to zero.

The platform control part 50 and its periphery are shown in FIG. 51 is a lifting motor, elevating a platform, 52 is a slide fork driving motor, and drives a slide fork. 22 is the tilt motor. The detection signals of the image sensors 36 and 37 are input to the inclination detection unit 54, and detect the inclination of the top unit of the slide fork from the difference between d1 and d2 in FIG. In addition, the remaining lifting distance from the distances d1 and d2 to carrying the article between shelves can be obtained. In the inclination detection using the image sensors 36 and 37, the inclination cannot be detected until at least one image sensor can detect the marks 31 and 32. Thus, the correction pattern storage unit 56 stores the tilt correction pattern when the top unit starts moving forward or backward on the platform or returns to the platform. The data of the correction pattern storage unit 56 is a target tilt angle of the lift table by distinguishing the forward / retracted position of the slide fork from the actual load or the empty load. In the area where the image sensors do not detect the marks 31 and 32, the platform is tilted by the data of the correction pattern storage unit 56.

6 shows a transfer algorithm in the embodiment. The image sensors 36 and 37 cannot detect the inclination of the slide fork until it advances into the shelf 30. In the case of the empty load and the actual load, the inclination of the slide fork 16 to the forward / retract amount is measured in advance, and the correction pattern is stored. At the start of advancement of the slide fork 16, the platform 2 is tilted in accordance with the data of the correction pattern storage unit 56 to move forward while keeping the top unit upper surface of the slide fork horizontal. When at least one of the pair of image sensors 36 and 37 detects the mark 31 or the mark 32, the height of the mark is stored. If the top surface of the top unit is horizontal, this height will not change even if the slide fork is advanced. Thus, the platform is tilted so that the upper surface of the slide fork is leveled so as to eliminate the change in height from the memory value. When both the left and right image sensors 36 and 37 detect the marks 31 and 32, the tilt of the top surface of the top unit can be accurately measured and the platform is tilted to eliminate the tilt.

When the forward end of the slide fork is finished, the tilt of the slide fork is detected by the image sensors 36 and 37, and the platform is changed from low to low speeds while the tilt is adjusted by tilting the platform 2 by a tilt motor. The article is received between the shelf 30 and then the platform is slowly lowered again to complete the transfer. Since the load applied to the slide fork is changed by the weight of the article, the tilt of the slide fork is changed, and the platform is tilted to correct this. Upon receipt of the article, the slide is retracted while correcting the tilt of the slide fork.

The speed pattern of the platform in an Example and a prior art example is shown in FIG. 7, Here, it raises a platform, but it is also the case of making it descend. The goods are received while the platform is rising in a short time. In the conventional example, the height of the slide fork cannot be precisely defined by the bending of the slide fork or the like. Therefore, in order to anticipate the ambiguity of the height of the slide fork tip due to bending, etc., it is necessary to increase the speed increase section. Thereby, conveyance time increases, the lifting stroke of the slide fork at the time of conveyance increases, and the storage efficiency of the article in a shelf side falls. In the embodiment, the tip of the slide fork is kept horizontal, so that the bottom surface of the article and the top surface of the slide fork are in surface contact from the beginning, so that the impact is small and the vibration of the slide fork after delivery can be reduced.

FIG. 8 schematically shows a process until the slide fork 16 is raised to load the article 17. In the embodiment, the platform 2 is tilted, but here, it is shown that the whole slide fork 16 is inclined by using two support parts which can adjust the height independently of the platform 2. Since the warp correction is performed on the platform side and the slide fork is held horizontally to come into contact with the article 17, the slide fork is in surface contact with the article. In addition, when loading from the slide fork to the shelf, the article is in surface contact with the shelf. For this reason, the impact by passing of an article can be made small. When the article is received, the load applied to the slide fork changes and warpage occurs. However, since the platform is tilted to eliminate the warpage, vibration caused by the warpage can be reduced. This allows the article to be delivered and received with a small impact, the short-speed lifting time can be shortened, the article can be transported in a short time, and the advancing / retracting is carried out while keeping the top unit of the slide fork horizontal. The efficiency is improved.

Although the stacker crane was shown as a conveying apparatus in the Example, it is the same also in the case of a ceiling traveling vehicle, a tracked trolley | bogie, an unmanned carrier vehicle, etc. Moreover, also in the case of the ground fixed conveyance system which combined the platform and the slide fork, the Example can be applied by providing the tilt mechanism of conveyance apparatuses, such as a slide fork. Although the slide fork was used as a conveying apparatus in the Example, a scalar arm etc. may be sufficient. Moreover, although one CCD camera with a wide horizontal field of view may be sufficient instead of a pair of left and right image sensors, the inclination detection accuracy falls.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the platform of the stacker crane of an Example,

2 is a view showing a tilt mechanism of the platform of the embodiment;

3 is a view showing the upper and lower marks formed on the shelf in the embodiment, and an image sensor installed on the top unit of the slide fork;

4 is a view showing a tilt detection method of a slide fork in the embodiment;

FIG. 5 is a block diagram showing a platform control unit, a lift motor, a slide fork driving motor, a tilt motor, and a storage unit of a tilt detection unit and a tilt correction pattern in an embodiment;

6 is a flowchart showing a transport method of an embodiment;

7 is a view showing the speed pattern of the platform of the embodiment (top) and the conventional example (bottom),

It is a figure which shows typically from the contact of the slide fork and an article to the lift up of the article from a shelf support in an Example.

<Description of Symbols for Major Parts of Drawings>

2: platform 4: mast

6: guide unit 7: linear motion guide (LM guide)

8: upper frame 10, 12: pin

14: tilt mechanism 16: slide fork

17: Item 18: long hole

20: Nut 21: Ball Screw

22: tilt motor 24: linear motion guide

26: guide unit 30: shelf support

31, 32: Mark 34: Middle unit

35: top unit 36, 37: image sensor

40, 41 Field of view 50: Platform control unit

51: lift motor 52: slide fork drive motor

54: tilt detection unit 56: correction pattern storage unit

Claims (3)

A conveying system having a forwarding / retracting arm and an article stage in which articles are received by the conveying apparatus, the conveying system comprising: forming at least two marks of the same height with respect to an article loading surface in two or more article stages; And detecting means for detecting a difference in height of the two or more marks on the arm of the conveying device, and moving the conveying device in the forward / retracting direction of the arm so as to eliminate the difference in the height position obtained by the detecting means. A conveying system, characterized in that a tilting means for tilting along the installation. The conveyance system of claim 1, wherein the mark is formed of a continuous line parallel to the article loading surface. The transfer system according to claim 1, wherein the detection means comprises at least one pair of optical sensors arranged at intervals along the forward / retract direction of the arm.

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