Kinematic pair

A joint in the art, such as in animals a movable connection between the two parts.

In contrast to animal joints exist in the art in addition to the joints for rotation (rotary joints) and which for displacement ( sliding or thrust joints). The bone joints of vertebrates are enveloped by the soft tissues (muscles, blood and nerve - tracks ), so that the interconnected bone does not rotate freely around each other, but can rotate only in a limited range of angles relative to one another. Therefore, the wheel does not occur in nature.

Joints in the art to distinguish the type f according to the relative movement and the number of degrees of freedom. It twists and thrusts can be combined together in a joint. A self-contained chain of four joints and four permanent members ( four-bar chain ) can be seen in every gear.

• Figure 2: pivot ( hinge ), f = 1
• Figure 3: screw joint, f = 1
• Figure 5: sliding pivot ( hinge plate ), f = 3
• Figure 6: sliding pivot, f = 2
• Figure 7: ball joint, f = 3