I sure wish there was. Perhaps one day HubPages can add a document download feature. I write lesson plans and I'd like to include a document or handout on some of my Hubs.
My current solution: Create your chart/doc on Power Point or Keynote and save as a photo. Upload that to your photo capsule. Your readers can save and print if needed by right clicking. It isn't a perfect solution, but it sort of works. (make sure the capsule is set to full size)
Another option (this one is debatable because it leads readers away from the site) Some blogs offer document file boxes for readers to download your docs. I know wordpress has it. You can direct your readers with a link to your file box and have them download the document.
Suggestion: make sure any links are relevant to your Hub and no more than two links per domain. Also, Sinea Pies has a hub called, Readers, How to Keep Them. The Hub will provide you with the html code that has the link open into another window. It is pretty easy. This way the reader does not leave your Hub.
Best wishes to you - I hope this helps. :)