See this example properly formatted in the QUT Cite tool.
In the text, cite the inventor and the year the patent was issued.
Inventor, I.I. (Year). Title of patent (Patent number). Official source.
Bell, A. G. (1876). Telegraphy (U.S. Patent No. 174,465). U.S. Patent and Trademark Office. https://patentimages.storage.googleapis.com/10/ab/a3/b4f5c6e5826640/US174465.pdf
Harbison, A. & Somerville, D. (2014). Clamp. (2013261258). AusPat.
Author is the name of the inventor to whom the patent was issued.
Year is the year the patent was issued (not when filed).
Source is the name of the official source of the patent information (usually the name of the patent office).
If the patent is found online, include the URL.