loose collet

I have a table mounted Triton router which has a ½ inch (12.7mm) collet. I often use a collet converter to take it from ½" (12.7mm) inch down to ¼" (6.35mm). I've repeatedly experienced issues with the ¼" becoming loose and effecting my work. :sad: Is there a trick to preventing the bit becoming...

Any suggestions on easy way to tighten the collet chuck on the arbor short of dis-assembly? Thanks, Jim