bultsammansaettning med that roterande laosande bulthuvud och that flytande bultelement foer automatiska eldvapen.

摘要

A bolt assembly for an automatic firearm which operates using kinetic recoil energy that includes a floating bolt element, a rotatable locking bolt head and a return spring interposed between them, all in communication with the barrel. The bolt head is formed with a cylindrical portion having two crescent shaped projections located at diametrically opposite points along the circumference of the cylindrical portion. The barrel is formed with two diametrically opposite recesses associated with and shaped to correspond to the projections. The barrel is also formed with a pair of grooves, each groove associated with a recess such that the projections may enter and exit the grooves through the recesses. The grooves are staggered with respect to the recesses and have an angular extension such that the projections may enter and be retained within the grooves. The barrel is additionally formed with projecting edge guide grooves and the bolt element is formed with projecting edges that are guided by the projecting edge guide grooves. The bolt head is also formed with a shank and a cavity is formed in the bolt element for receiving the shank. The shank carries a pin that is adapted to impart a rotary movement to the bolt head by engaging a helical slot formed in the bolt element. Upon firing, the return spring is compressed which momentarily keeps the bolt head in a locked position which causes a delay to allow for the dissipation of pressures in the barrel.