Security door system

A security device, comprising:

• a hollow casing having a interior space with a longitudinal axis, and first and second casing ends;
• a first rod assembly positioned in the interior space, the first rod assembly comprising a first rod extending parallel to the longitudinal axis and having first and second rod ends, a first spring positioned at the first rod end, and a second spring positioned at the second rod end, wherein the first and second spring exert longitudinal compressive force;
• and
• a second rod assembly positioned in the interior space, the second rod assembly comprising second and third rods parallel to the first rod, and a third spring positioned between the second and third rods, wherein the third spring exerts longitudinal compressive force;
• wherein the third spring does not overlap the first or second springs with respect to a plane perpendicular to the longitudinal axis.

A security device, comprising:

• a hollow casing having a casing interior space with a longitudinal axis, and first and second casing ends;
• parallel first and second rods in the casing interior space;
• and
• a first spring in the casing interior space, the first spring positioned to exert longitudinal compressive force on the first rod;
• an end plug sized and shaped to fit in the casing interior space, and having a threaded opening;
• and
• a set screw received in the threaded opening, the compressive force adjustable by the set screw.