I tried searching on The Lens and Google Patents for "plug" and "Thyco" as the assignee. I got no hits on either. This is not surprising as it is possible that the patent, if one exists, could be assigned to the inventor or a different company's name. If you search the web, however, you do find some vintage lamps with Thyco plugs from the 1930s and '40s. Beyond this, I don't think we can help you very much short of searching every patent relating to electrical plugs. If you are driven to learn more, you should try searching the patent sites yourself. I'll warn you that using "electrical plug" as the search term on The Lens yields 965,713 hits. I did find similar images on Google Image Search using "Thyco Plug Electric Cord Lamp" as the search term.