It's already been discussed on here how to find internships/temporary research opportunities at universities and also when exactly to do an an internship at a company during one's PhD, but there doesn't seem to be much information on how someone goes about finding internship/temporary research opportunities at companies.
There are a few companies which do stuff which is very similar to what I'm researching, and a couple of those are even posting full-time jobs for work nearly identical to my own albeit looking for people who are more experienced in the field than I currently am. How can I approach said companies which are actively working on my own research topic (more or less) with a proposal to spend a period of time working with them?