Hi John - those pics are taken from Henry Dreyfuss' very important book, 'Designing for People'. If you don't have a copy of this, it's essential reading - you can find it on eBay very reasonably priced. It's a general overview of the concept of ergonomics and people-centred design, his personal philosophies, and his methods of working. It has some amazing anecdotes in it, and provides a wonderful insight into the mind of the man who 'sculpted' Hoover for so many years!
My own copy is slightly later than the version printed above, and features a different design case-study (a sewing machine, possibly made by Singer - someone's borrowing my copy at the moment!) Look for the earlier edition if you want the Hoover case study.
I photocopied the pics I posted above from the copy owned by the Surrey Institute of Art and Design, where I studied for two years after leaving college. I'd do my assignments at home at night, and spent the days reading through their library's vast catalogue of graphic and industrial design books - they had some amazing stuff! I learnt more that way than I did from any of my tutors!