In a dual joystick mechanism, regardless of which joystick serves as the active component, there will always be two dead center positions. In order to avoid dead center positions, in practice, the rocker should be restricted from reaching its limit position. In hyperbolic mechanisms, due to the lack of reciprocating components, the mechanism has no limit position, so there is no dead center.
The existence of institutional dead points is generally unfavorable, and efforts should be made to avoid or pass them smoothly. But in some cases, people use the characteristics of the dead center position of the mechanism to achieve certain work requirements. For example, the suspension and compression devices of FA401 and FA506 fine yarn machines both use the dead center position of the mechanism to lock the suspension.
Although the four-bar mechanism has a simple structure and convenient design, it is sometimes difficult to meet the complex design requirements of modern machinery in various aspects. At this point, it is necessary to rely on a multi rod mechanism. A multi bar mechanism can be seen as composed of two or more four-bar mechanisms.
Due to the large number of dimensional parameters of multi bar mechanisms, they can meet more complex or precise motion and trajectory requirements. There are many types and structural forms of it, generally divided into five bar, six bar, eight bar mechanisms, etc. according to the number of bars.