Patents are part of the US constitution! The right to protect intellectual property of inventors is included in the original document as a way to encourage innovation.
U.S. Constitution - Article I Section 8 | Clause 8 – Patent and Copyright Clause of the Constitution.
[The Congress shall have power] “To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries.”
In order to be patentable, an invention must meet three criteria:
Patents are legal documents, so as you might expect, they describe inventions in legal terms. But since they are about inventions they incorporate engineering terms as well.This creates a special language hybrid that can make searching less straightforward than one might hope. Depending on the era the invention was patented, you also need to consider how language changes over time–spelling, meaning, usage, etc. can be very different to how you might describe something now.
For example, you might recognize this patent drawing as the "Skip-It" toy from your childhood. But you know it by it's brand name rather than the title of its patent "Skipping toy and method of playing same."
On this patent, there is a lot of helpful information, such as the  Inventors,  Assignee,  References Cited,  International Classification number for the patent,  additional US patent classification numbers. Additionally, detailed technical drawings accompany all patents.