1941 1 July 22/7 Compulsory attendance time is not paid for, only actual working time ‘on the clock’.
2002 June 74 Oh no, you can't go down there. You'll be there for hours and we're on the clock here.
2015 J. Braun vii. 155 ‘Oh, no wine for me. I'm on the clock.’ She winked. ‘What would my boss say?’