Braking system for manual foldable wheel chair: we design a brake for wheel chair locking brake for parking how to get dimension from wheel chair.for brake model we have which type of analysis or formulas used to get the dimension for brake and design a model.for example shear force but not neccesary for brake my point of view so we have which type of work done for it .just explain his method and write his formulas must. explain in detail and take an example for explaining this should be very good. so I am design a locking brake how can we do for its dimension the analysis explain.