Bob Ploskunak, a retired Woodland Hills teacher, has invented a safety device that can prevent shooters from entering school classrooms.
WTAE-TV reports that Ploskunak's invention, JAMBLOCK, a lightweight piece of steel, can be slipped under a classroom door and secure it in place, preventing intruders from entering. While it doesn't directly protect students, it does buy more time until police arrive at the scene.
Ploskunak, who had been an industrial arts teacher at Woodland Hills High School, retired from the school district in 2011 after 35 years of service,
For more about Ploskunak and the device, click here for WTAE's story.