Technical Data Top chain Handling
4-1. Handling sprockets
In general, square shafts are recommended for the drive and driven shafts used with plastic modular chains, except for special cases (such as mold-to-width type chains and right-angle transfers using TOD).
Because changes in temperature will cause the chain to expand and contract, sprockets must be mounted so that they are free to move laterally in the across-the-width direction.
However, to prevent meandering (snaking) of the chain, one (or two) sprocket(s) should be locked in position in the center of both the drive and driven shafts using setscrews or set collars and hexagonal socket head cap screws.
When installing the sprockets on the square shaft, the inscribed markings or identification marks should be used to orient the sprockets so that they all face the same direction and to keep the position of the teeth aligned.
4-1-1. Phase Matching of Sprockets
Install the sprockets on the shaft in such a manner that the direction and the position of all the inscribed markings or identification marks on the sprockets are aligned.
Split Sprockets
Solid Sprockets
4-1-2. Chain Expansion/Contraction
Plastic modular chain is made of polymer resin, and will expand and contract with changes in temperature.
A rough estimate for linear chain expansion is 12×10-5 (/°C) using 20°C as the reference temperature.
The expansion per nominal width (⊿W) is found using the following formula:
⊿W = chain nominal width × (Operating Ambient Temperature - 20) × 12 × 10-5
(Example) For K60 chain (1,524 mm wide) used in an environment where the temperature rises from 20°C to 60°C:
⊿W = 1524 × (60 - 20) × 12 × 10-5 = 7.3mm
4-1-3. Locking Sprockets
The sprockets and the shaft are loosely fitted in order to absorb differences in thermal expansion between the chain and the conveyor and also installation errors of the chain and the sprockets. However, a setscrew, a hexagonal socket head cap screw, or a set-collar should be mounted on each side of a sprocket installed around the center with about 0.5 mm (1.6 mm for WT) clearance with the sprocket in order to prevent meandering motion in the chain.
* Fix the sprocket to be installed between the tab guide attachments when using a chain equipped between tab guide attachments.
4-1-4. Chain Installation
Wind the chain onto the sprockets installed at the given intervals.
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If the sprockets are installed at the wrong interval, the chain may run over the sprocket and break. Make certain of the center distance between the sprockets.
