Safety Design of Stacker

1. Status switch

The status switch is used as the execution part and the information feedback part of the stacker. The quality of the status switch directly affects the normal operation of the stacker. The status switch includes the left middle position, the right middle position, the left end position and the right end. Switches such as position, lift address recognition, lift alignment, speed change, walking address recognition, stock availability, cargo detection, etc., as the execution part, while executing instructions, it also feeds back the execution progress to the PLC in real time for analysis by the PLC. Issue appropriate instructions.

2. Protection switch

The protection switch is used as the protection part of the stacker. The quality of the protection switch affects whether the stacker can operate safely within the controllable range. The protection switch includes fork over, cargo over, limit, loose For switches such as ropes and stalls, the stacker can be controlled to operate within a controllable range only when the protection switch is in good condition, so as to avoid unnecessary loss of property and personnel due to the loss of control of the stacker.

1. Schematic diagram of switch installation The following figure shows the installation diagram of partial state switches and protection switches:

Installation diagram of up and down speed change and limit switch
Middle and end installation diagram
Schematic diagram of loading platform switch installation

Switch and device function description

Serial number
Device name
Device type
Device model
Function Description
1
Upper and lower limit
Automatic stop device for upper and lower limit
Photoelectric switch
When the cargo platform exceeds the upper limit or lower limit of the working stroke during the lifting process, the main circuit contactor is automatically cut off, and the lifting frequency converter and the lifting motor are forcibly cut off.
2
Inside and outside limit
Automatic stop device for inside and outside limit
Limit switch
When the cargo platform exceeds the limit position of the inner or outer limit of the working stroke during the traveling, the main circuit contactor is automatically cut off, and the traveling inverter and traveling motor are forcibly cut off.
3
Loose rope overload
Overweight protection device
Limit switch
When the chain or wire rope of the stacker loading platform is loose, or the stacker loading platform is overweight, the main circuit contactor is automatically cut off.
4
Elevator stall
Stall protection device
Proximity switch
When the chain or wire rope of the loading platform breaks, or the loading platform is stuck on the shelf, the loading platform slides down at a high speed and automatically cuts off the main circuit contactor.
5
Fork over protection
Fork protection device
Photoelectric switch
If the left or right side of the stacker fork exceeds, the stacker PLC does not give output and the motor stops rotating.
6
Cargo protection
Cargo protection device
Photoelectric switch
If the left or right side of the stacker cargo exceeds, the stacker PLC will not give output and the motor will stop rotating.
7
Cargo Detector Switch
Cargo check device
Photoelectric switch
In the case of warehousing, if there are already stocks at the destination address, it will be notified that there are stocks, and the alarm will be “double warehousing” to avoid collision.
8
Change speed
Automatic speed reduction device at the end of lifting
Photoelectric switch
During the lifting and lowering process of the cargo platform, if the low-end or high-end speed changing device of the column is located, the high-speed is automatically turned off and the low-speed is connected to prevent the lifting and over-limit device from being exceeded at high speed.
9
Speed ​​change
Automatic speed reduction at the end of walking
Photoelectric switch
During the traveling of the cargo platform, if the speed changing device is at the inner or outer end of the traveling, the high-speed is automatically turned off and the low-speed is connected to prevent the traveling overrun device from being exceeded at high speed.
10
Fork change speed
Change speed from high speed to low speed
PLC program
When the fork is extended to the end or neutral position, the program automatically changes the high speed to low speed operation to prevent the cargo from collapsing due to inertial impact.
11
End switch
Fork end stop device
Photoelectric switch
When the fork extends to the end position, the power supply of the fork inverter and the fork motor is automatically cut off.
12
Neutral switch
Fork center stop device
Photoelectric switch
When the fork returns to the neutral position, the power supply of the fork inverter and the fork motor is automatically cut off.
13
Lift address
Lifting address recognition device
Photoelectric switch
During the automatic lifting process of the stacker, it is used to memorize and judge which layer is currently located.
14
Lift stop
Lift stop device
Photoelectric switch
When the stacker reaches the target floor, the lifting stop device will automatically stop when it is judged to be in a low or high position.
15
In stock switch
Checking device for goods on loading platform
Photoelectric switch
It is mainly used to detect whether there is goods on the loading platform. During the pickup operation, if the pickup process is completed and no goods are detected, the alarm will be “empty pickup”.
16
Way of working
Mode interlocking device
Way button
Only one of the four modes of online, stand-alone, manual, and overhaul can be selected.
17
Address exceeds
Automatic job address overrun detection
PLC program
If the address received by the stacker does not match the actual address during operation, the PLC will not act.

Leave a Reply