A Time Travel novel with Unregulated use of a Time device by a middle aged(?) man.

I've read this book so long ago and was young it's hard to remember what hapoened and what didn't. This is what i believed happened. A middle aged man who used to work for a time patrol agency ends up using the device without permission and visits different time periods where they're clearly marked with a year like a sort of train station. I think the device was a suitcase but i'm not sure. He changes into the years' clothes and stays with some people who take him in for some time. I think he wasn't the only one to be freely moving around time. I've been looking for this book for ages now have near given up.