Abstract: The present invention relates to an inertial device to permit and to prevent motion between two members, for example, the tubing and the body of a central reactor in a thermal or nuclear power station.

Abstract: Device for inhibiting relative movement between two articles in dependence on the speed of said movement comprises a box connected to one of said articles, a screw connected to the other article and mounted to slide freely in the box, and a nut rotatably mounted on the screw. If the screw is rapidly accelerated, the nut thereon is forced against a friction surface so that it cannot rotate, and this prevents further longitudinal movement of the screw. If, on the other hand, the screw moves slowly, the nut will turn on it, and permit continued movement by the screw.

Abstract: A shock absorber for automatic weapons of the kind where all the shots in a burst with the exception of the first are fired during the return movement to the initial position of the weapon. The weapon has a recoil member movable with respect to a fixed member to absorb the impact and resilient restoring means for restoring the recoil member to its initial position. Braking means brake the movement of the recoil member during recoil. The braking means are inoperative or of reduced effect during the recoil movements relative to all the shots in the burst other than the first shot.