Bird swing detector

Claim 1

Apparatus for inspecting containers for ''''bird swings'''' comprising, a horizontal, moving belt conveyor for supporting a plurality of containers to be inspected, a vertical light beam source mounted at one side of said conveyor, a multi-faceted mirror mounted in front of said light source and adapted to reflect a beam of light impinging thereon, a pair of spaced-apart vertical plates extending parallel to the conveyor adapted to maintain containers in line in series, one of said plates having a vertical slit formed therein extending from a position slightly above the surface of the belt conveyor to a point corresponding to the shoulder height of the tallest container to be inspected, said mirror and light beam being so positioned relative to said slit that the beam of light is reflected from said mirror through said slit in a direction substantially normal to the plates, a pair of spaced-apart, vertically extending photosensitive elements positioned opposite to said slit in an opening in said other plate, said elements being out of direct line-of-sight of said reflected beam of light, means covering said elements to limit the field of illumination of said elements to vertical paths of reflected or deflected light from a ''''bird swing'''' connection to the adjacent wall of said container and illuminated by said beam of light.