Construction and Kinematics of Automotive Side Door Latch Mechanisms

Automotive side door latches are considered safety-critical systems due to both federal and automotive OEM regulations. The paper presents a kinematical study, in terms of degrees of mobility, and the basic construction for an example mechanism utilized as an automotive side door latch. This system is represented and approximated with mechanisms with articulated bars, cams and gears. Mobility calculations for such type of mechanisms involve both the determination and the investigation of all involved kinematical elements and the nature of their mobile restraints (called kinematical couples). By applying the principles and the methods described in this paper similar investigations in terms of the degree of mobility for other side door latch design applications can be investigated.