when I go looking for ideas,
first I usually have a need or desire, that I would like to have a machine or an attachment to fulfill a need,
usually I look for machines that I could buy, (most seem out of my price range), then I look at the completed machines for Ideas, and most of the time I find that blending the different ideas are helpful, many times I will look up the patents and down load to see what they feel is so special, most instances the patens is expired, and usually do a search for other patens that have expired,
(most ideas are not that good, IMO) and remember most patens are the first draft of the machine, usually not that refined, I draw up some sketches of the desired unit with the different variants of the idea used, chose the ones I like, then usually order the parts I think I will need or collect them if used and on hand, then start to put the final measurements on the drawings and start to build, most of the time I start with the part that really has the least flexibility for changes and work out from there, many things are made to fit, even tho I have rough over view, but normally do not take the time to come up with a final drawing of exact fit, as the working parts many times evolve a little in the process of actual fit, (and some thing are just trial and error).
If I am under standing correctly patens are good for 20 years, or less,
Term of patent in the United States - Wikipedia, the free encyclopedia