Bar stock silencer tube

Claim 2

A sound attenuating bar stock feed tube comprising in combination an elongated inner tube, the inner tube including on its exterior a covering of non-metallic sound-absorbing material, a concentrically disposed elongated outer tube having an internal diameter greater than the external diameter of the inner tube to thereby define with the inner tube an annular space, closure means for said annular space at each end, a layer of lead shot in said annular space, said lead layer having a thickness of between approximately 0.090 to 0.120 inches, said layer of lead shot being formed of a particle size in the range of approximately 0.030 to 0.050 inch whereby it forms a loose layer of between 2 and 3 courses of particles.

Claim 3

A sound attenuating bar stock feed tube comprising in combination an elongated inner cylindrical feed tube, an outer cylindrical tube concentric about and of substantially the same length as said inner tube, said outer tube having an inner diameter greater than the diameter of an outer surface of the inner tube whereby an annular space is formed between the inner and outer tubes, closure means at each end of said annular space, at least one layer of woven fabric in contact with and wrapped about said outer surface of said inner tube, the thickness of said woven fabric layer being selected in relation to the outside diameter of said inner tube and the inside diameter of said outer tube to leave a radial clearance zone in said annular space of about 0.090 to 0.120 inch between said fabric layer and the inside surface of said outer tube, a layer of lead shot in said annular space, said shot being provided with a particle size in a range of about 0.030 to 0.050 inch whereby it forms a sound-absorbing layer of approximately 2 to 3 courses of loose particles.

Claim 4

A sound attenuating bar stock feed tube comprising in combination an elongated inner cylindrical feed tube, an outer cylindrical tube concentric about and of substantially the same length as said inner tube, said outer tube having an inner diameter greater than the diameter of an outer surface of the inner tube whereby an annular space is formed between the inner and outer tubes, closure means at each end of said annular space, at least one layer of woven fabric in contact with and wrapped about said outer surface of said inner tube, the thickness of said woven fabric layer being selected in relation to the outside diameter of said inner tube and the inside diameter of said outer tube to leave a radial clearance zone in said annular space of about 0.090 to 0.120 inch between said fabric layer and the inside surface of said outer tube, a layer of lead shot in said annular space, said shot being provided with a particle size in a range of about 0.030 to 0.050 inch whereby it forms a sound-absorbing layer of approximately 2 to 3 courses of loose particles.