JPH01303209A - Pallet extrusion detection device for stacker crane - Google Patents

Abstract

PURPOSE:To prevent a wrong action by changing the stop positiono of the fork center position of a stacker crane according to the extrusion quantity of a pallet, and dividing the extrusion quantity in the right and left in the captioned device for an automatic warehouse. CONSTITUTION:A projector 7 and a light receiver 8 are arranged in the outer side of the width of a frame 4, and the stop position of a fork 5 is changed according to the extrusion quantity of a pallet 6 by providing a certain width in the right and left. For example, the fork 5 is corrected so as to be stopped to the right of a mechanical center. The division of the extrusion quantity to the right and left of the frame 4 in this way enables an extrusion acceptance quantity to be approximately two times the former quantity and the interval 12 between the frame 4 add a rack 1 reduced. Thus a wrong action and the lowering of workability can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to automated warehouses, and particularly to a pallet protrusion detection device suitable for a safety device of a stacker crane.

[Conventional technology]

Conventionally, detectors have been installed on the left and right sides of stacker cranes to prevent collisions between racks and pallets caused by pallets protruding from the stacker crane.

Incidentally, related devices of this type include, for example, JP-A-51-120565, JP-A-61-2602, and JP-A-61-64604.

[Problem to be solved by the invention]

In the prior art, in order to prevent collision accidents between racks and pallets due to pallets protruding from the stacker crane, a method was adopted in which detectors were installed on the left and right sides of the stacker crane. However, the method of installing the detector within the width of the stacker crane results in predictive detection, which lacks reliability. Also.

If the detector is installed in the gap between the rack and the rack outside the width of the stacker crane, detection will be ensured, but if the gap between the detector and the rack is small, a collision will occur between the detector and the rack, and if this gap is made large, the warehouse building will be damaged. becomes less space efficient. To prevent space efficiency from decreasing, move the detector closer to the stacker crane.

Deformation of pallets, tolerances of racks, etc., wear of rails, etc. can cause unnecessary detection operations, which increases the number of times the system goes down and deteriorates work efficiency.

An object of the present invention is to solve the above three problems in the method of installing a detector outside the width of the stacker crane.

[Means to solve the problem]

The above object is achieved by changing the stopping position at the fork center position to the left and right according to the amount of pallet protrusion, and dividing the amount of protrusion into the left and right sides of the stacker crane.

[Effect]

The pallet protrusion detection device operates when the fork of the stacker crane takes out a load from the left or right rack and returns to near the center position. The stop position at the center of the fork should be a little wider to the left and right than the mechanical center position.
The stop position is changed by the signal from the detector. If the pallet protrudes, move the stop position away from the mechanical center to reduce the amount of protrusion. At this time, the end of the fork protrudes on the opposite side of the protrusion by the amount that absorbs the amount of protrusion, but by dividing the protrusion into the left and right sides of the stacker crane, the protrusion dimension of the detector from the stacker crane can be halved.

If the amount of protrusion is one larger than the allowable amount, after performing the above operation, either the left or right detector is still detecting the end of the pallet, and the stacker crane is brought down to ensure safety.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. The stacker crane 3 stores or takes out the cargo 2 to or from the adjacent rack 1 separated by 722 in the left and right directions.

This operation is performed by extending the fork 5 provided on the frame 4 of the stacker crane 3 to the left or right rack 1. Immediately before the load 2 is stored or taken out, the fork 5 is located at the mechanical center of the stacker crane 3, and the pallet 6 is loaded on the fork 5 at approximately the same position as the fork 5.

However, if the pallet 6 is deformed or defective, the position of the pallet 6 may shift from the position of the fork 5 and protrude toward the rack 1, resulting in a collision between the rack 1 and the pallet 6. For this reason, a pallet 6 protrusion detector is installed,
In the case of protrusion, a safety device such as cutting off the main power supply of the stacker crane 3 is required.

An example of a method for detecting protrusion is shown in FIGS. 2 and 3. 1st
The figure shows a method in which a light emitter/receiver 9 for detection is housed inside the width of the frame 4 of a stacker crane.

FIG. 3 shows a method in which a detection light emitter 7 and a light receiver 8 are mounted at positions projecting outward from the width of the frame 4.

The former method is an indirect method in which the amount of protrusion Q, 8 is predicted using the detection dimension Q4, and therefore has the disadvantage that detection is not reliable. The latter directly detects the protruding pallet 6, so
It has the advantage of being able to detect reliably without being affected by defects in the shape of the pallet 6, but because it protrudes outside the frame 4, the projector 7. If the distance Q1 between the receiver 8 and the rack 1 is small,
The rack will collide with the light emitter 7 and the light receiver 8, and if a detection device is attached, the distance between the rack 1 and the frame 4 must be increased, which impairs space efficiency.

In the present invention, in order to solve the latter drawback, the conventional fork 5
The stop position of the fork 5 is mechanically centered at the center position of the fork 5, but a certain range of width is provided to the left and right, and the stop position of the fork 5 is changed according to the amount of protrusion of the pallet 6. According to the above configuration, even in the case where the conventional method shown in FIG. 3 would have lowered the stacker crane 3 due to overhang, as shown in FIG. 4, by stopping the fork 5 to the right of the mechanical center, The amount of protrusion on the left side can be kept below the allowable amount. That is, conventionally, the amount of protrusion was detected only on the left side or the right side, but in this embodiment, the amount of protrusion is divided into the left and right sides of the frame 4, and the allowable amount of protrusion is approximately doubled. In other words, if the allowable amount is the same, the projector 7. The amount of protrusion of the detector of the light receiver 8 from the frame 4 can be reduced to about half that of the conventional one, the distance Ω2 between the frame 4 and the rack 1 can be reduced, and deterioration of space efficiency can be prevented.

If the amount of protrusion exceeds the allowable amount, as shown in FIG. 5, even if the fork 5 protrudes from the right emitter 7.degree.
Since it protrudes from the light receiver 8, safety measures such as cutting off the main power supply of the stacker crane 3 are taken.

Note that FIGS. 2 to 5 are only examples, and the same effect can be obtained even if the direction of protrusion is reversed left and right.

〔Effect of the invention〕

According to the present invention, it is possible to reduce the gap between the rack and the stacker crane and detect the same amount of protrusion, which improves the space efficiency of automated warehouses, and even if the amount of pallet protrusion is the same, the fork center position Since the stopping position at the stacker crane is changed, the allowable amount of protrusion can be increased, which has the effect of reducing work efficiency loss due to the stacker crane going down.

[Brief explanation of the drawing]

FIG. 1 is a side view of an automated warehouse according to an embodiment of the present invention, FIGS. 2 and 3 are side views of a stacker crane section showing a conventional example of protrusion detection, and FIGS. 4 and 5 are side views of an automated warehouse according to an embodiment of the present invention. It is a side view of the stacker crane part of one Example.

Claims (1)

[Claims] 1. A rack that stores cargo, a stacker crane that is installed between the racks to move goods in and out of the rack, and a detector that is installed outside the width of the stacker crane on the left and right sides of the stacker crane to detect when pallets protrude from the stacker crane. A pallet protrusion detection device for a stacker crane, characterized in that the stop position at the fork center position of the stacker crane is changed according to the protrusion amount of the pallet, and the pallet protrusion amount is divided into the left and right sides of the stacker crane.