A hinge is a type of bearing that’s used to join two objects while allowing one or both objects to partially rotate. Kitchen cabinets, for example, often feature a hinge that allows the door to open and close. The hinge typically won’t allow the door to open all the way. Rather, the door can only open within a specific degree of rotation. When connecting larger and heavier objects together, a special type of hinge, known as a geared continuous hinge, is used.
Like other hinges, a geared continuous hinge is used to connect two objects. It differs from other hinges, however, by featuring gear teeth inside a vertical cap. When a geared continuous hinge closes, these teeth mesh together.
Geared continuous hinges also support an array of fasteners that are used to distribute the weight of the joined objects. As shown in the image here, a typical geared continuous hinge contains a dozen or more holes for fasteners like screws.
Origins of the Geared Continuous Hinge
The origins of the modern geared continuous hinge can be traced back to the 1960s when MIT engineer Austin Baer received a patent from the United States Patent and Trademark Office (USPTO) for a hinge featuring meshed gears. Later, in 1968, Baer received a second patent for another hinge design that featured thrust bearings.
How a Geared Continuous Hinge Works
A geared continuous hinge works by securing two objects together using two flat pieces of metal. With that said, it offers greater support than other types of hinges thanks to its embedded teeth as well as support for an array of fasteners. In applications where the hinge will be exposed to stress, such as the weight of a heavy exterior door, geared continuous hinges are often used.
The Different Types of Geared Continuous Hinges
There are several types of geared continuous hinges. While all of them feature gear teeth inside a vertical cap, each type has its own unique design. Mortise geared continuous hinges, for example, are designed to fit into a shallow cut in the objects on which they are installed. For doors, this style is preferred because it allows the door to rest flush with the jamb, ensuring the door opens and closes properly.
There are also “swing clear” geared continuous hinges. Unlike other types of hinges, swing clear geared continuous hinges are able to completely rotate. In other words, doors or objects on which they are used can fully open.