Abstract: A fuel cell stack compression system in which a spring assembly and mechanical linkage assembly are used in conjunction with tie rods and tie bars to apply a compressive load to a fuel cell stack. The linkage assembly includes a lever and three pins to redirect the force or movement generated by the spring assembly into a movement or force for the tie rods. The tie rods, in turn, connect to the tie bars which span the top end plate of the fuel cell stack and transfer the load to the stack. The linkage also includes a slotted bearing which compensates for the circular arc formed by the lever and allows the spring assembly to be rigidly mounted under the bottom end plate. The spring assembly comprises multiple springs arranged in parallel and designed to provide a non-linearly decreasing load as the stack compresses due to cell consolidation. This load profile reduces overall stack shrinkage while providing high pressure at the beginning of life to insure proper cell-to-cell contact.

Abstract: A shutter mechanism comprising an aperture through which ambient light is passed to cause a film exposure, a pair of shutter blades supported for pivotal opening movement in opposite opening directions away from one another to uncover the aperture to permit ambient light to pass through the aperture and for pivotal closing movement in return closing directions towards one another to re-cover the aperture and supported to allow them to be pivoted simultaneously in the same direction to cause accidental shutter opening when a physical shock is applied to the shutter blades in the opening direction of one of the shutter blades, is characterized in that each one of the shutter blades completely covers the aperture in order that both of the shutter blades must be removed from the aperture to uncover the aperture to permit ambient light to pass through the aperture, and a single fixed stop is positioned between the shutter blades to prevent either one of the shutter blades from pivoting in the same direction as the