there are 1000s of hinge patents. Here is the abstract of one issued in 2015 "A hinge device for a door is provided. The hinge device has two hinge members whi

there are 1000s of hinge patents. Here is the abstract of one issued in 2015 "A hinge device for a door is provided. The hinge device has two hinge members which engage with each other and a hinge cap. A bearing with one or more tapered ends engages with the hinge members to allow easy opening and closing of a door attached to the hinge device." https://patents.google.com/patent/US9290974?oq=hinge+2018 https://patents.google.com/patent/US9290974?oq=hinge+2018