Hinge Hinge A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation: all other translations or rotations being prevented, and thus a hinge has one degree of freedom. Hinges may be made of flexible material or of moving components. In biology, many joints function as hinges like the elbow joint. There are many types of door hinges. The main types include: Other types include: Since at least medieval times there have been
Bell's hinge-back tortoise Bell's hinge-back tortoise Bell's hinge-back tortoise ("Kinixys belliana") is a species of African tortoise, from the family Testudinidae. It has the hinge that characterizes all tortoises in the genus "Kinixys". There are several subspecies (some of which may actually be separate species; see below) and the Bell's hinge-back tortoise is subject to wide variation throughout its extensive range. Both the specific name, "belliana", and the common name are in honor of English zoologist Thomas Bell. Bell's hinge-back tortoise is a medium-sized light brown tortoise. They can grow up to 22 cm. On the back of its shell, the tortoise has