Can an invention patent have no circuit? A simple electromechanical device?

The mechanical structure diagram is given in the application, and the innovative explanation of the method and steps is given. The circuit diagram of measurement and control is complicated, so I don't want to draw it. Is it okay? You can apply for an invention patent, but now the integration of the circuit is very high. If a machine needs to add a lot of peripheral circuits in order to attach your patent, but it can't be integrated with the original high integration circuit, I'm afraid there won't be many manufacturers who want to adopt your patent. LCD TV, in particular, is also pursuing volume. Now they are a thin screen body, and there is no place to add additional circuits.