Patents are not what you think, and there is no way to limit them to your county-level cities.
In this case, it is good to apply for appearance or utility model. It doesn't cost much The agency fee plus handling fee, plus all other fees, including the annual fee for the first year, should be able to apply for a patent for utility model of about 3,000 yuan (provided that the application fee is reduced and it is easier to apply). This design may be cheaper.
However, for the record, the application of this thing is only effective for some small workshops. If a really powerful manufacturer wants to use your patent, he can try to make it invalid.
That's all, I hope to adopt it, but I don't know how to keep asking.