Many mechanical applications involve the use of springs with specifically designed load-displacement characteristics. This paper presents a new mechanical concept, that uses prestressed nonlinear plate springs that can be designed for various load-displacement characteristics for the end effector of parallelogram linkages. An intuitive method is proposed to design the global geometry of the nonlinear plate springs within the given set of boundary conditions from the parallelogram. The results from this method enhance understanding in the design of nonlinear springs and can be used as initial condition for structural shape optimization methods. Three distinct spring characteristics are found using this method to show its applicability. The springs are modelled by a finite element model and validated with a protoype.