Does anyone know where to check the legal status of American patents?

On the homepage of the government website of the United States Patent and Trademark Office (website: http://www.uspto.gov/), enter the "patent" item on the left, and select the small item "Search for patent" to enter the "Patent Electronic Commerce Center" page (website: http://www.uspto.gov/patft/index.html).

On the page of Patent Electronic Commerce Center, select "Patent Application Information Retrieval" to enter the legal status inquiry page.

There are five digital selection boxes on the retrieval interface: application number, patent number, publication number, etc. Only one digital form can be selected for each retrieval; Usually we choose the patent number.

There are 10 buttons at the top of the patent description data recording page, namely:

(1). Select a new case: return to the search page;

(2). Application data: application data page;

(3). Transaction history: apply for viewing the transaction history;

(4) Image file package: communication files between the examiner and the applicant and various files written by the examiner when examining and approving this patent;

(5) History of patent extension: the history of patent extension;

(6). Continuation data: the continuation data of the patent, which determines whether the patent has related information such as continuation application, partial continuation application and divisional application;

(7). Foreign priority: foreign priority;

(8) Fees: payment of patent fees;

(9) Published documents: showing the full-text page of this patent;

(10). Address & Lawyer/Agent: displays the address of the patent applicant and the relevant information of the lawyer or agent.

Check the patent payment.

To view the patent payment, you can click the "Fee" button in the patent description data page to enter the patent payment query database (which contains the payment data of all authorized patents published on the latest publication date).

The basis for the expiration of American patent rights:

After the US patent is granted, the maintenance fee will be paid in three installments: the fourth year, the eighth year and the twelfth year after the grant. At the same time, the latest payment time before the search date is determined to obtain the payment year.