DeWalt and Stanley Black & Decker: patent first
DeWalt's support pages point inventors to Stanley Black & Decker's idea submission process. It only considers ideas covered by a granted utility patent or a published patent application, and submissions that don't meet its guidelines are returned without review. Check the current terms on stanleyblackanddecker.com before you send anything.
Klein Tools: no outside ideas
Klein Tools states that it does not accept unsolicited product ideas or improvement suggestions, citing legal risk. Physical materials are sent back and electronic files are deleted unreviewed. Klein does take feedback on its existing tools through its normal customer channels.
Milwaukee Tool: no published process
We couldn't find a public submission policy from Milwaukee. The company talks about working with users on jobsites, but if you want to pitch an idea, the only way to learn its current position is to ask its customer service directly, and to read whatever terms they send back before sharing details.
Why big brands are this cautious
A large brand usually has many products in development. If it reviews your idea and later releases something similar it built on its own, it risks a dispute. Requiring a patent, or refusing outside ideas entirely, is how they avoid that. It isn't a judgment on your idea.
What that means for you
Keep dated records of your design, sketches and tests. If you want a brand like DeWalt to look at it, you'll need a filed application that has published or a granted patent, so speak to a registered patent attorney or agent before disclosing it anywhere. Read any submission agreement in full: many say the company owes you nothing for reviewing it.
Some smaller tool companies and suppliers run their own suggestion forms or invention programs, so the brands you already buy from may be worth asking. Our earlier note on turning a homemade tool into a product covers the questions to answer before spending money.
Where we stand
We don't take ideas on commission or buy inventions either. What we do want is the problem: the last time a step on your jobs needed a second person or a rigged-up fix. That conversation never asks you to disclose a design.