Resilient breech for microballistic printers

In a breech for use in microballistic printers in which projectiles having a predetermined cross-sectional diameter are successively fired through a gun, said breech comprising a resilient restricted projectile receiving opening of predetermined diameter through which projectiles of larger cross-sectional diameter are to be forced, the combination of a plurality of metallic elements, means confining said elements in a circulr array to define said projectile receiving opening, and a resilient plastic material embedding and filling all interstices between said elements to form a gaseous seal surrounding said projectile receiving opening.

In a breech for use in microballistic printers in which projectiles having a predetermined cross-sectional diameter are successively fired through a gun, said breech comprising a resilient restricted projectile receiving opening of predetermined diameter through which projectiles of larger cross-sectional diameter are to be forced, the combination of a plurality of metallic spheres, means for confining said spheres in a circular array in which the innermost points of said spheres define said projectile receiving opening, and a resilient plastic material embedding and filling all interstices between said spheres to form a gaseous seal surrounding said projectile receiving opening.

In a breech for use in microballistic printers in which projectiles having a predetermined cross-sectional diameter are successively fired through a gun, said breech comprising a resilient restricted projectile receiving opening of predetermined diameter through which projectiles of larger cross-sectional diameter are to be forced, the combination of a cup comprising a cylindrical wall and opposed end walls each having a central opening aligned with said projectile receiving opening, a plurality of spheres confined within said cup in a circular array, the innermost points of said spheres defining said projectile receiving opening, and a resilient plastic material embedding and filling all interstices between said spheres to form a gaseous seal surrounding said projectile receiving opening.

In a breech for use in microballistic printers in which projectiles having a predetermined cross-sectional diameter are successively fired through a gun, said breech comprising a resilient restricted projectile receiving opening of predetermined diameter through which projectiles of larger cross-sectional diameter are to be forced, the combination of a cup comprising a cylindrical wall having a predetermined inner diameter and opposed end walls each having a central opening aligned with said projectile receiving opening, six spheres each having a diameter greater than one-third of the inner diameter of said cylindrical wall, said six spheres being positioned by forcing into said cup in a circular array under stressed equilibrium in which the innermost points of said spheres define said projectile receiving opening with a diameter less than the diameter of each of said six spheres, and a resilient plastic material embedding and filling all interstices between said spheres to form a gaseous seal surrounding said projectile receiving opening.