Troubleshooting   Small size conveyor chain

When there is significant damage or breakage to the chains or sprockets, carry out the following remedies or replace with new chains and sprockets as necessary.

General

1 Chain is riding up on the sprocket
2 Unusual noises
3 The chain winds onto the sprocket. (Poor separation from sprocket teeth.)
4 Wear on the inside surfaces of the link plates and sides of the sprocket teeth.
5 Excessive wear on the link plate side surfaces and pin heads
6 Poor chain articulation
7 Spreading of link plates

Plate related

8 Sudden link plate fracture
9 Cracks form in the link plate (fatigue) that are perpendicular to the direction of pull
10 Deformation of link plate holes
11 Corrosion stress cracks appear (bow-shaped cracks in the link plate)

Pin related

12 Breakage of pin
13 Pin rotates or begins to protrude

Bush/roller related

14 Roller and/or bush cracks (falls off)
15 Roller does not rotate, or unsymmetrical roller wear
16 Roller is opening up
17 Roller is becoming hourglass shaped
 Answers

General

1
[ Click to enlarge ]
Chain is riding up on the sprocket
Cause 1 Chain and sprocket do not match Solution Replace the chain or sprocket with the correct size.
Cause 2 Excessive load Solution Decrease the load (and consider pump lubrication), or increase the number of strands or size of the chain.
Cause 3 Chain wear elongation or excessively worn teeth Solution Replace with new chains and sprockets.
Cause 4 Insufficient chain winding angle Solution Set angle to 120o or more, or for three teeth or more.
Cause 5 Insufficient back tension Solution Set or adjust the catenary and take-up.
Cause 6 Center distance between chain and sprocket shaft Solution Inspect and adjust.
Back to list
2 Unusual noises
Cause 1 Improper installation of the sprocket or shaft Solution Inspect and correct
Cause 2 Chain casing or bearings are loose Solution Tighten all bolts and nuts.
Cause 3 Excessive/insufficient slack in chain Solution Adjust the distance between shafts to obtain the proper amount of slack
Cause 4 Excessive chain or sprocket wear Solution Replace with new chains and sprockets.
Cause 5 Lack of or unsuitable lubrication Solution Provide proper lubrication according to the operating conditions
Cause 6 Chain or drive area interfering with the casing. Solution Inspect and adjust.
Cause 7

Guard rail not properly installed


[ Click to enlarge ]

Solution Inspect and adjust.
Back to list
3
[ Click to enlarge ]
The chain winds onto the sprocket. (Poor separation from sprocket teeth.)
Cause 1

Excessive chain slack

Solution Adjust the chain length or distance between shafts
Install a tensioner
Cause 2 Chain wear elongation or excessively worn teeth Solution Replace with new chain or sprocket
Cause 3 Chain and sprocket do not match Solution Replace with new chains and sprockets.
Cause 4 Poor articulation due to rust
Insufficient lubrication or poor environment
Solution Replace the chain and protect the chain from the environment through lubricating or installing a casing.
Back to list
4 Wear on the inside surfaces of the link plates and sides of the sprocket teeth.
Cause 1 Improper installation Solution Correct sprocket and shaft installation
Cause 2

Chain is being pushed laterally.


[ Click to enlarge ]

Solution Remove the cause of the lateral forces and switch to a chain with guide rollers.
Back to list
5 Excessive wear on the link plate side surfaces and pin heads
Cause 1

Improper installation of guides, etc.


[ Click to enlarge ]

Solution Check the condition of the guide and widen the space between guide and chain.
Back to list
6
[ Click to enlarge ]
Poor chain articulation
Cause 1 Deformation of chain due to inproper installation Solution Inspect the installation and correct as necessary
Cause 2 Contamination from wear dust or dirt due to improper lubrication (grease, etc.) Solution Remove the chain, clean, and lubricate appropriately.
Cause 3 Overload, pin bending, bush cracking Solution Reduce the load, or increase the chain size or number of strands.
Cause 4 Corrosion or rusting Solution Install a casing to protect the chain
Cause 5 Insufficient lubrication Solution Lubricate sufficiently.
Cause 6 Foreign matter or conveyed goods caught in the clearances between pins, bushes, and rollers. Solution Install a casing to protect the chain
Cause 7 Usage in high temperatures Solution Contact a Tsubaki representative to ensure that the clearances are appropriate.
Back to list
7 Spreading of link plates
Cause 1

Uneven or excessive loading caused by improper installation


[ Click to enlarge ]

Solution Replace with a new chain and adjust the installation.
Back to list

Plate related

8
[ Click to enlarge ]

1. Static fracture

Pulling a link plate with a tensile load beyond its breaking load will cause it to stretch and then break


[ Click to enlarge ]

2. Fatigue fracture

There is a load in excess of the fatigue limit (fatigue strength), causing fatigue from the inside of the plate hole and sudden fracture midway.


[ Click to enlarge ]

3. Offset link plate fatigue

Offset link plates are bent at the center, and the resulting concentration of stress at the bend can cause a fatigue break. Avoid using offset links in high-stress applications.

Cause 1 Excessively large shock load Solution Reduce shock loads by making the start-up, stopping, and other actions smoother (by installing a shock absorber, etc.).
Increase the chain size or increase the number of strands.
Cause 2 Chain vibration Solution Install an anti-vibration device (for example, a tensioner or idler sprocket).
Cause 3 Corrosion Solution Replace with a new chain, protect the chain with a casing, and clean and lubricate your chain regularly.
Back to list
9 Cracks form in the link plate (fatigue) that are perpendicular to the direction of pull
Cause 1 A load larger than the maximum allowable load is acting on the chain. Solution Eliminate the overload or the excessive repetitive load, or increase the chain size or number of strands.
Cause 2 A repetitive load is acting on the attachments. Solution Ensure there are no overloads, or increase the chain size/attachment allowable load.
Back to list
10
[ Click to enlarge ]
Deformation of link plate holes
Cause 1 Overload Solution Remove the cause of the excessive load and replace with a new chain.
Back to list
11
[ Click to enlarge ]
Corrosion stress cracks appear (bow-shaped cracks in the link plate)
Cause 1 The chain is being used in an acidic or alkaline environment.
(This is not caused by a repetitive load.)
Solution Replace with a new chain, and protect the chain from the ambient environment with a casing.
Consider specifications with greater resistance to stress corrosion fracturing.
Back to list

Pin related

12
[ Click to enlarge ]

1. Static fracture

How the chain shears when breaking
Occurs when a load greater than the chain's fracture strength acts on a chain in use.


[ Click to enlarge ]

2. Fatigue fracture

Occurs when the pin is repetitively subjected to loads greater than its fatigue limit. Re-check the size of the peak load and formulate a countermeasure.


[ Click to enlarge ]

3. Shock-induced bending fracture

The pin is subjected to a large shock load and breaks. The origin side receives the tensile load, and the fracture progresses from an origin point. A pin is especially susceptible to becoming weak with regard to bending when the surface of the pin has cor

Cause 1 Excessively large shock load Solution Reduce shock loads by making the start-up, stopping, and other actions smoother.
Cause 2 Pin subjected to a repetitive load greater than its fatigue limit Solution Eliminate the excessive repetitive load, or increase the chain size/number of strands.
Cause 3 Corrosion Solution Use a casing, and clean and lubricate your chain regularly.
Back to list
13
[ Click to enlarge ]
Pin rotates or begins to protrude
Cause 1 Excessive load or improper lubrication Solution Replace with new chain. Improve the lubrication or loading conditions.
Cause 2 When a chain is not lubricated properly under heavy loads, abnormal frictional force will develop between pins and bushes, causing the pins to quickly rotate. Operating a chain in this condition will cause the pins to extract and lead to chain breakage. Solution Replace with a new chain immediately. Never weld the pins or reuse old pins. (Always dispose of old chains to ensure that they are not reused.) Check the mounting condition of the chain if the pin heads and plate sides are worn as well.
Back to list

Bush/roller related

14
Cause 1 Inadequate lubrication Solution Replace the chain. Provide adequate lubrication according to the operating conditions
Back to list
15 Roller does not rotate, or unsymmetrical roller wear
Cause 1 RS25、RS35 Solution A bushed chain instead of a roller chain is being used
Cause 2 The inner plate is moving inward, or the bush is cracked Solution Replace the chain. Re-inspect the installation and load conditions
Cause 3 Foreign matter has gotten between the bush and roller Solution Remove regularly, and use a casing to protect the chain.
Cause 4 Roller load is excessive. Solution Lighten the load, or go a chain size up.
Cause 5 Conveyed goods or foreign matter is accumulating in the frame. Solution Remove regularly, and protect the chain with a divider system.
Cause 6 Rust on bushes/rollers. Solution Reselect for the appropriate specifications (or material)
Cause 7 Inner plate is moving inwards. Solution Replace, reexamine installation, and reexamine load.
Back to list
16 Roller is opening up
Cause 1

Overload


[ Click to enlarge ]

Solution Reduce the load, and provide adequate lubrication
Back to list
17 Roller is becoming hourglass shaped
Cause 1 Excessive load or inadequate lubrication Solution Replace with new chain. Improve the lubrication or loading conditions.
Back to list