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
Bicycle saddle forward and backward and to tilt up and down around the axis of the bolt. There are two common types of built-in saddle clamps for standard rails, both associated with genericized trademarks: I-beam rails are long and allow a wide fore-aft adjustment range. I-beam saddle clamps use two clamping bolts for grab pieces holding the single rail. Other historical saddle clamp variations included the Ideale saddle/Zeus post combination, which used a special seat post designed to forgo the need for a clamp in order maximize weight savings. A saddle may contain one or more suspension components to improve rider comfort