Concrete insert for poured concrete floors

A device for disposing in concrete structures for attachment of support fasteners comprising:

• a shaft having a head at a first end and a hole therein at a second end, a plurality of slots disposed in an external surface oriented parallel to said shaft longitudinal axis and extending to said second end, a plurality of retaining recesses disposed in said external surface intermediate said slots and approximately parallel to said slots wherein said retaining flats do not extend to said second end, and a plate groove circumferentially formed in said external surface intermediate said first end and said second end wherein said plate groove intersects said slots and said retaining recesses;
• a plate having an aperture that is the approximate form of a lateral cross section of said shaft wherein said aperture at an edge having a plurality of projections extending radially inward disposed to engage said slots when said shaft is slidably inserted in said aperture;
• a spring disposed on said shaft retained between said head and said plate slidably disposed on said shaft;
• and
• said plate retained on said shaft against said spring force by rotating said plate in said plate groove from said slots to position said projections in said retaining recesses.