Study of “Special Positions” Using the Example of a Four-Bar Hinge Mechanism

This scientific article examines the types of "special provisions" of spherical four-link mechanisms, their features and conditions of their occurrence. It has been established that there are articulated four-link mechanisms with one, two and three special positions. At the same time, it is also determined that mechanisms with two special positions are divided into mechanisms with symmetrical and asymmetrical special positions according to the location of special positions relative to the inter-support distance. The influence of "special provisions" on the change in the law of movement of the links of the mechanism and the possibility of their use in the creation of vibration impact machines is considered in detail.