The text and illustrations of US patents published before March 1, 1989 are in the public domain unless the patent text contains a specific notice that portions are copyrighted. See
37 CFR 1.71(d),
37 CFR 1.84(s)
The original patent contains no such notice, so its contents are in the public domain.
Note: This only applies to images published before March 1, 1989. Patents published after that date are most likely copyrighted, unless in the public domain for another reason, such as
{{PD-ineligible}}.
这张图片属于美国政府专利号3789832 filed 17 March 1972, issued Feb 5, 1974. 图片来自美国专利商标局。
Summary
This image belongs to a US govt Patent number 3789832 filed 17 March 1972, issued Feb 5, 1974. Image is from the US Patent and Trademark Office.