immediately that any linear acceleration acting on the center of mass m1 which tends to cause the actuating member 1 to move in an anti clockwise direction can be ignored since this will tend to reinforce the grip between the hook 4 and the detent 5 thus preventing the buckle from becoming released thus any acceleration on the mass m1 capable of opening the buckle must be towards the left as shown in fig2 thus effectively the acceleration must have a component which acts in a direction to the left i e the acceleration vector must be directed at an angle u03b8 shown in fig2 which can have any value in the range of 90 u00b0 to 90 u00b0 in fig2 the acceleration direction is shown by the arrow accel the spring 9 applies an equal and opposite force to the actuating member and the latching member this force being ff the spring force ff is applied to the actuating member 1 and the latching member 2 at a distance h above the plane carrying the axes of rotation p1 and p2 it is assumed for the sake of the following mathematical analysis that the detent 6 contacts the projection 7 and an equal and opposite force p is exerted on the detent 6 and the projection 7 when subjected to a linear acceleration equilibrium for the actuator member is defined.