Automatically retractable chalk and plumb line assembly

Claim 1

Automatically retractable chalk and plumb line assembly, comprising a housing in the form of a plumb bob having tapered lower and upper ends and being divided into two compartments, said housing being formed with a first and a second opening into one of said compartments, said second opening being located in an upper end of said one compartment, a reel disposed in said one compartment with a plumb line wound thereon and being unwindable so as to extend out of said housing through said second opening, said one compartment being fillable through said first opening with powdered chalk freely engageable with said reel and plumb line disposed within said one compartment, the other of said compartments being sealed against penetration by chalk from said one compartment and having a helical spring disposed therein for rewinding said plumb line on said reel, and including a wall disposed between said compartments, and a rotatable shaft disposed in said other compartment and extending therefrom into said one compartment, said helical spring being secured at one end thereof to said rotatable shaft in said other compartment and at the other end thereof to another location within said other compartment, said reel being mounted on said shaft in said one compartment, said other compartment being formed with an opening through which an end of said rotatable shaft extends, and including an L-shaped tongue having a rounded end and being engageable with said end of said rotatable shaft for inhibiting rotation thereof, said tongue being slidable in a groove formed in said housing and located adjacent said opening formed in said other compartment, and including means for locking said tongue against said end of said rotatable shaft, said end of said shaft being formed with at least one flat portion at the periphery thereof and including means for locking said tongue, in a fully extended position thereof, against one of said flat portions of said shaft, said tongue, in another position being disposed so that said rounded end thereof is alternately engageable with said flat portions and rounded peripheral portions of said shaft for gradually slowing down rotation of said shaft.