First of all, one of the connecting rod and the frame must be the shortest rod.

Second, the sum of the lengths of the shortest bar and the longest bar must be less than or equal to the sum of the lengths of other bars.

Definition of crank-rocker mechanism: A hinged four-bar mechanism with a crank and a rocker is called crank-rocker mechanism. Usually, the crank is the driving part and rotates at the same speed, the rocker is the driven part and swings back and forth at variable speed, and the connecting rod does plane compound motion. The rocker is also used as the active component in the crank-rocker mechanism, which converts the reciprocating swing of the rocker into the rotation of the crank. Crank and rocker mechanism is the most basic form of four-bar mechanism.

A four-bar mechanism refers to a linkage mechanism with four members (including a frame).

English name: four? Rod mechanism

Applied disciplines:

Mechanical engineering (first-class discipline), mechanism (two disciplines), linkage mechanism (third-class discipline)

Refer to Baidu Encyclopedia crank rocker mechanism.