Abstract: A shock isolator apparatus of the pressurized air type having a plurality of cylinder chambers and a piston positioned for movement in the cylinder chambers. An air passage tube axially located in the piston permits air to flow between one end of the piston extending into a first end chamber in the cylinder and a chamber formed in the piston at an end opposite the one end. Air communication between the end chamber, the chamber formed in the piston, and a second end chamber in the cylinder is accomplished by air bypass ports extending between the air passage tube and the second chamber. Unidirectional pressurized valves positioned between chambers of the cylinder operate to equalize the pressure distribution throughout the cylinder.

Abstract: A viscous dampened sensitive pendulum carries a generally upwardly directed light source for indicating the gravity vertical. The sensitive pendulum is carried for two degrees of pivotal freedom by flexural pivots which are biased for operation at an error free or hysteresis free zero spring rate for small pivotal deflections. A drive pendulum coupled through the flexural pivots to the sensitive pendulum maintains a small pivotal deflection so that error free, zero spring rate, operation is achieved.