When were sunbeds first invented or developed was it by Wolff or Kellogg or neither?

Sunbeds were first developed in the 1970s, primarily by German inventor Friedrich Wolff, who created the first commercial tanning bed. While John Harvey Kellogg is known for his health and wellness contributions, he did not invent sunbeds. Thus, it was Wolff who played a pivotal role in the invention of sunbeds.