Methodology to Improve the Performance of the End-stop Buffers of Suspension Seats

The aim of this study was to optimise the characteristics of the bottom end-stop buffers of compact suspension seats fitted to fork lift trucks with a load-lifting capacity of less than 3.5 tons, earthmoving equipment, farm tractors and plants intended for forestry work. This work required the development of a numerical model of a seat subject to movements likely to cause impact with the end-stop buffer. The model employs a global approach based on modelling the friction phenomenon of the suspension mechanisms by means of Bouc—Wen's behavior law. After validation, the model was used to calculate the optimal characteristics (stiffness, damping and height) of the bottom end-stop buffers of the seat. Prototypes of optimised end-stop buffers were produced from the optimal characteristics calculated. Comparisons between the nominal end-stop buffers and the optimised buffers were made in the laboratory using the excitation signals recorded in the field. The results show that when the optimised end-stop buffers were fixed to the seat instead of the nominal end-stop buffers, between 73% and 93% of the maximum achievable gain was obtained at the acceleration peaks.