JPS5936016A - Abnormal rotation detector for rotary rack - Google Patents

Abstract

PURPOSE:To improve the accuracy of detecting abnormal rotation in an endlessly-rotated rotary rack with a tray by outputting an abnormal signal when with a tray driving motor turned on electricity, a signal proportional to the tray moving speed is not input within a fixed time. CONSTITUTION:While a tray is driven, a timer 18 is operated by a motor turn- on state detecting signal F. When the tray is moved at a normal speed, before a preset time passes, a detection signal from a photoelectric switch PHS-F is input as a reset signal G to the timer 18, and the timer is set at 0. Accordingly, an abnormal rotation detection signal M with the lapse of the preset time is not output. If the moving speed decreases, and a reset signal G is not input within the preset time, however, the timer 18 is not set at 0, so that an abnormal rotation detection signal H is output with the lapse of time, and a motor-off command is provided to stop the driving of a motor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation abnormality detection device (so-called locked state, etc.) of a rotating rank, which includes multiple trays that are connected in an endless manner and move on a circulation path.

Generally, in this type of rotary rack, if the tray becomes unable to drive for some reason and stops abnormally while the drive motor is energized, a The system was configured to detect abnormal rotation using a thermal relay for overload detection, cut off power to the motor, and display an abnormal stop if necessary. However, although this thermal relay is effective for abnormal stoppages such as when an overload is applied to the motor, it is not suitable for use when, for example, a chain used as a transmission means from a motor to a tray drive chain or the tray is connected in an endless manner. It just doesn't work at all for abnormal stoppages caused by breakage of the chain etc. (
If a variable motor is used and the rotation speed drops due to a failure in the control means or voltage drop, and the tray movement speed drops abnormally, this situation can be detected (emergency). I can't make it stop.

In view of the above-mentioned problems, the present invention reliably detects as an abnormal rotation state when the moving speed of the lulu drops below a certain level while the tray drive motor is energized, regardless of the cause. The present invention provides a rotational abnormality detection device that obtains the following results.

Hereinafter, one embodiment of the present invention will be explained based on the attached illustrative drawings. In FIG. ! 6
4 is a tray attached to the endless chain 1 in an equidistant manner, and 5 is interlockingly connected to the drive gear 2 through a chain transmission means 6. This is a tray drive motor. As shown in FIGS. 2 and 3, each rule 4 includes a detection plate 7, a support guide roller 8, a support guide rail 9, a steady rest guide roller 10, and a steady rest guide rail 11. It is supported so that it can circulate in a fixed posture on a horizontal circulation path. PIIS-F and PHS-R are a pair of photoelectric switches ζ for detecting the detection target plate 7, and are attached to a fixed location beside the tray movement path at an interval that allows both ends of the detection target plate 7 to be detected simultaneously.

Of the series of trays 4, the origin tray 4a, which is tray No. 0.1, is equipped with an origin detection plate Fj7a, and an origin detection photoelectric switch 2 that detects only this origin detection plate 7a.もP I-I S-X is the pair of photoelectric switches P II S-F, P 11 S-R
placed in between.

Next, the structure and operation of the entire control device will be explained based on FIG. F, PH3-[? Utilizing the detection signal from the machine, an addition/subtraction counter function that apologizes during forward rotation and subtracts when reverse rotation outputs a unique tray number for each tray passing through the cargo handling position. In addition, the photoelectric switch P
The detection signal of HS-X is based on the counter value as the origin (positive 1
) Used to return. Reference numeral 15 denotes a comparison circuit, which compares the call I/Lux inputted thereto with the detection tray inputted manually from the above-mentioned Lu tooth detection means 12;
It outputs a deceleration command A when the previous tray on the 1-roux movement direction side passes the calling tray, and outputs a coincidence signal C when the calling tray positive and the detection tray floor match. .

14 is an OR gate element, 15 is an AND gate element, and by the action of these two gate elements, when the n;1 deceleration command A is being output, the photoelectric switch lll
When any of the detection signals 5-F, PI-(S-R) is output, a stop command B is output. 16 is a stop position check circuit, and after the stop command (3) is output, a stop command B is output. After a certain period of time (a time set slightly longer than the expected time required for stopping) has passed, a coincidence signal C is output, and a detection signal is output from both the photoelectric switches PIIS-F and PIIS-R. Then, a stop completion signal, which is used as a start signal for the automatic load transfer device at the load handling position, is output, and otherwise the drive device 17 including the tray drive motor 5 is in the stopped state. When the inching operation is started, a stop position correction command E is output.

Reference numeral 18 is a timer that can set an arbitrary time, and here, when the rule 4 is being driven at a normal speed,
A time slightly longer than the time interval at which the detection signal is output from the photoelectric switch PIIS-FIJ (i.e., the time required for the tray 4 to move one pitch per tray) is set, and the It operates at 61 o'clock only when there is an energization state detection signal F, and the photoelectric switch P HS
-F is received as a reset signal G to be reset to zero, and when the set time has elapsed, a rotation abnormality detection signal (1) is output as a motor power supply circuit OFF command.

Incidentally, when the tray 4 is being driven at a low speed due to the deceleration command, the time set in the timer 18 is set to be slightly longer than the time required for the I-route 4 to move one tray by one bisodge during this low-speed movement. Automatically switched to time. To switch the set time, the deceleration command can be used as a set time switching command.

According to the above configuration, in order to call the trays 4 on the selected specific floor to the cargo handling position, the drive device 17 is operated with the call 1-route positive set at a constant state-the ζ motor 5 circulates the series of trays 4. When the tray 4 is moved, the detection means 12 sequentially outputs the calm of the tray 4 passing through the cargo handling position.
The comparator circuit 1i5 compares the rou yang and the loading tray 0, and when the rou 4, which is one tray before the loading tray 0, passes the cargo handling position, a deceleration command is output, and the drive device 17 receives this deceleration command. (The rotational speed of the motor 5 is automatically reduced to a predetermined low speed. In this way, after the ream 4 moves at a low speed, Photoelectric switch located in 1) IIS-F
When Plls-R () when moving forward) or Plls-R () when moving backward) detects the detection target plate 7 of the tray 4, a stop command B is output, and the drive device 17 receives the stop command B and drives the motor 5. The drive of the tray by the motor 5 is stopped, and the drive of the tray by the motor 5 is stopped.
switch to dynamic braking mode. Therefore, the series of i-rails will move a certain distance due to inertia and then stop. As a result, the call tray 4 is placed at the cargo handling position, and both ends of one detected object @ 7 are connected to a pair of photoelectric switches l) It S-F.
, I' II S-R will stop accurately within the range of, for example, ±IQ sm.

When the tray 4 is driven by the motor 5 (as described above), that is, when the motor 5 is in the energized state, the timer 18 is activated by the motor energization state detection signal F. When moving at normal speed, the photoelectric switch P is activated before the set time elapses.
Since the detection signal from HS-F is manually input to the timer 18 as the reset signal G and reset to zero, the abnormal rotation detection signal H is not outputted as the set time elapses.

However, if the moving speed of the tray 4 abnormally decreases for some reason even though the motor 5 is energized, or if the tray 4 becomes locked and stops abnormally, the reset signal G is activated by the timer 18. The set time elapses before the rotation abnormality detection signal II is input. This detection signal H switches the motor power supply circuit of the drive device 17 to OFF, and the power to the motor 5 is cut off. Of course, it is also possible to electrically indicate the emergency stop state due to abnormal rotation by means of an alarm, revolving light, or the like.

In the embodiment, a photoelectric switch PklS-, which is one of the detection switches for detecting the loop, is used as a means for outputting a detection signal at time intervals proportional to the moving speed of the loop as it moves. F and the detection target plate 7 provided on the tray 4 are used, but a dedicated means can also be provided separately. Furthermore, this means is not limited to the method of detecting the detection target part provided on the tray 4, but also a method of detecting the detection target part provided on a rotating member that rotates in conjunction with the tray 4. You can also do that.

Furthermore, although the embodiments use individual control means or circuits, it is actually possible to use a computer in conjunction with the program control method. FIG. 5 is a flowchart showing the flow of program control when implementing the present invention using a computer.

The rotational abnormality detection device of the present invention can be implemented as described above. and a means for outputting a rotation abnormality detection signal when the detection signal is not input within a preset time while the motor is energized and in a state of 1ζ. By setting the set time to a time slightly longer than the time interval at which the detection signal is output when the tray is being driven at a normal speed, the tray drive motor is energized. However, if the moving speed of the tray decreases abnormally or the tray stops abnormally due to a lock condition, the tray may stop abnormally due to a cause that cannot be detected by a thermal relay, or the rotation speed of the motor itself. If the motor decreases abnormally due to a failure in the rotation speed control system or voltage drop, regardless of the cause, a rotation abnormality detection signal will be output from the motor. Safety can be ensured by automatically turning off the circuit or taking other necessary measures.

[Brief explanation of drawings]

Figure 1 is a schematic perspective view illustrating the configuration of the rotary rack;
The figure is a plan view showing the relationship between the tray and the detection switch.
4 is a block diagram explaining the present invention in detail, and FIG. 5 is a flowchart showing the flow of control when executed by program control using a computer.
It is. DESCRIPTION OF SYMBOLS 1...Endless chain, 2...Drive gear, 6...Idle gear, 4...Rule, 5...Tray drive motor,
7゜7a...Detected plate (detected part), 12...Tray depth detection means, 15...Comparison circuit, 16...Stop position determination circuit, 17...Rule drive device, 18 ...
Timer,])]H3-F, IIIS-1? , PIIS
-X...Photoelectric switch (detection switch), A...Deceleration command, B...Stop command, I...Motor energization state detection signal, G...Re-Figure 4 If?

Claims (1)

[Claims] In a rotating rack equipped with a large number of trays that are connected in an endless manner and move on a circulation path, means for outputting a detection signal at time intervals proportional to the moving speed of the trays as the trays move; means for outputting a rotational abnormality detection signal when the detection signal is not input within a preset time while the motor for circulating the rotation is energized. rotational abnormality detection device.