The sketch below shows the forces acting on the latch hook at the moment of unlatching when all the forces are concentrated at the edge of the detent.
Summing moments about the latch hook axle,
From the point of view of the air cylinder, at the moment of unlatching, Fr is broken into 2 components, the load the cylinder needs to exert and the load transmitted to the walls of the latch housing.
The force required to be exerted to unlatch is
We have a 2" bore cylinder. When it is unlatching, the effective area of the piston is 2.7 in2. The latching effective area is 3 in2. The pressure required to exert the unlatching load comes from:
This should be considered a bore minimum unlatch pressure. I would like to see 90 psi or better. (Latching requires more pressure. We discovered this experimentally. LB 8/20/97) BR>
Last modified 04/28/99