Meanings of is no patent in английском

As there is no patent on the contrivance, anybody can make the boxes for himself.

There is no patent on the thing, and I don't mind letting you all into it.

There is no patent medicine we can feed the American people and cure it of its diseases.

When the American virologist Jonas Salk was asked who owned the patent to the polio vaccine he invented, he famously replied: There is no patent.