PREVENTATIVE MAINTENANCE:
VERTICAL CAROUSEL - SERIES 2400

Overview:

The 2400 (aka: Vertical Carousel, VC2400, etc) uses a conveyor/load chain type mechanical assembly to rotate vertically up or down via top sprockets and lower sprockets (attached via a torque shaft) on the left and right sides. These load chains hold the pan assemblies (aka: shelves, tubs, etc) with which all types of material is stored. The load chain is rotated similar to a theme park ferris wheel via a motor, gear box and motor drive chain connected to the torque shaft. The 230 VDC motor is run via an electronic control system that handles the conversion of AC to DC power. There are also 230 VAC motors powered via an AC inverter. Furthermore the electronic controls monitor the stopping position, safety circuits and over current draw from load deviation in the 2400. Like any other mechanical device similar to an automobile, the 2400 requires periodic maintenance based on: age, usage and weight load. Assuming the unit has been installed properly, i.e. shimmed, leveled and plumbed; the moving parts as well as the electronic parts require periodic attention A.K.A. - Preventative Maintenance.

Conveyor/Load Chains:

• The conveyor/load chains similar to a bicycle chain (only on a very large scale) will “wear in” (a.k.a. stretch) and become loose. Age, usage, and weight load has a great bearing on the amount of wear the load chain can incur.
  
• Scissors arm weldments are suspended upon extended pins on the load chains, which have load chain chain guide rollers attached to them (on both sides of the chain) to allow uniform travel up and down the internal vertical chain track. The scissors arm weldments can wear (egg out) at the point of attachment on the pins if the chains become loose and/or dry.
  
• Trunnion plate scissors arm assemblies have the pans attached to them on both sides. Each trunnion plate assembly has a stabilizing arm with roller. This roller is used as a guide to maintain stability and levelness of the pans as they are rotated through the tracking system.

Motor Chain:

• Connects the gear reducers drive sprocket to the driven sprocket on the torque shaft.
• Will become loose over time.
  

Lower and Upper Curved Stabilizing Tracks:

• Located at the top and bottom on both the left and right sides, allowing the cam arm rollers to travel smoothly throughout it's rotation.
  

Chain Tracks:

• Guides the load chain guide rollers on the extended pins to ride smoothly up and down in a vertical path.
  

Upper Load Chain Bearing/Sprocket Assemblies:

• Allows the load chains to rotate smoothly and efficiently in a vertical path.

Torque Shaft:

• Enables the load chains to rotate uniformly in a vertical path. The hardened bolts that connect the torque shaft on the left and right sprocket weldments must be inspected and re-torqued if necessary.
  

Motor Control Enclosure:

• Houses the input and output wiring for the motor control voltage, system control voltage, PCB I/O-Processor, Safety I/O, Regen Motor Controller, as well as other integral circuitry.
  

Product Protect/access Safeties:

• Require periodic inspection for the safe operation of the 2400.
  

Computer Interface Devices:

• All have electrical connections and power supplies which will require inspection.

Possible Failures Due to Lack of Maintenance:

When the load chain stretches, all other components are affected. The cam arms cannot move smoothly through and around the curved stabilizing tracks. The load chain guide rollers cannot effectively pass through the chain track. The upper sprockets bearings may wear and possibly fail. The motor chain will stretch and become sloppy. When the load chains stretch the cam arm rollers as well as the load chain guide rollers are “forced” through the tracking system, no longer riding smoothly and efficiently.

• The cam arm rollers will soon wear irregularly. When this happens the roller will possibly get caught on, or bumped out of the tracks causing the pan to jam or flip shutting down the machine. This will cause damage to the pan and possibly other numerous parts.
• With the cam arm rollers being forced through the curved tracks, the load chains will over wrap the lower sprockets causing the guide rollers to buckle, eventually breaking the vertical guide track(s). Over time the rollers can get caught on the damaged vertical guide track and break the extended pin(s). When this happens the scissors arms weldments will fall and the pan will flip at the top/bottom or get stuck at the bottom on the floor, thereby shutting the machine down. A flipped pan may become damaged as well as the scissors arm weldments and require replacement.
  
• The attachment point or hole of the scissors arm weldments where they fit over the pins on the load chains will “egg out” a.k.a. - become oval and loose. If this happens the trunnion plates and pans will rock as they travel through the tracks. This will cause disruption of the continuous flow of the conveyor system and cause failure to the other above mentioned components.
  
• The motor chain as it wears will become loose. With the weight distribution and erratic condition of the worn load chains and associated parts, can possibly skip over the drive sprocket on the motors gear box. This can cause a safety concern as if the chain skips the pans will not stop properly and will drift until the chain catches again. The chain can possibly break and get jammed inside the machine, causing additional damage even allowing the pans to “free wheel”.
  
• Lack of lubrication will cause stiffness in all moving parts, premature wear and eventual failure.
• The cam arm rollers as well as the load chain guide rollers being forced through the the tracking system will become worn and loose over time; therefore possibly getting caught on the tracking system. If they get caught and stuck, the system will shut down and potentially flip a pan damaging numerous parts.
  
• With loose load chains and other fatigued components, product may creep out of the pan(s) and get caught on other pans, causing potential damage and down time.
  
• If the hardened bolts on the lower torque shaft connections become loose, the torque shaft bolts can shear. This can allow the left and right load chains to be come out of sync with each other causing the pans to jam and possible damage to other moving parts.

Preventative/Corrective Maintenance:

1. Visually and audibly observe the operation of the machine.
   
2. Remove pans if required for 3, 4, 5, 6 & 7.
   
3. Re-torque the conveyor chains to factory specifications if required.
   
4. Adjust lower curve track to factory specifications in order for the stabilizing cam arm rollers as well as the guide rollers to track properly, if necessary.
   
5. Inspect lower and upper curved stabilizing tracks for wear. Replace as necessary.
   
6. Check the bolts on the torque shaft. Tighten (re-torque) if loose.
   
7. Inspect the vertical guide track for wear, and repair as necessary. Welding may be required
   
8. Check for level and plumb.
   
9. Inspect guide rollers and replace as necessary.
   
10. Inspect cam arm rollers for looseness/wear. Replace as necessary.
    
11. Inspect a sample scissors arm weldment for wear. May require all to be replaced if excessive wear is shown.
    
12. Tighten the motor drive chain if required.
    
13. Lubricate all wear points, chains.
    
14. Inspect/test all product protect safeties, and wiring. Repair, replace, re-secure as required.
    
15. With a DVM test all input and output voltages.
    
16. Adjust motor control voltage and current output as necessary.
    
17. Inspect floor as the pan bottom passes through for clearance. Re-level if too close.
    
18. Replace any removed pans and test run.
    
19. Inspect any options, peripherals, etc. added to the 2400. Adjust, clean, etc. as necessary.
    
20. Clean the debris and lubricants from the floor inside the machine. This will allow observation of wear during the next regularly scheduled maintenance.

Follow Up Maintenance:

The 2400 has been a tried and true work horse for many decades. Based on usage and weight load in the 2400, a maintenance program should be in effect to promote it's longevity with minimal down time. Machines with long term neglect will benefit greatly from a comprehensive PM to extend the life of them. With a regularly scheduled maintenance program there will be less down time. Properly working 2400's will improve product picking and improved efficiency in other areas as well. Regularly scheduled maintenance permits “scheduled” down time for the maintenance. Always schedule follow up maintenance after completing a regularly scheduled maintenance. Always have failing or weak components replaced as soon as reported, especially the product protect and access safeties.

This document or any of its contents may not be copied or reproduced in any way without the written consent from: Logic Level Technologies, Inc.