clasp lock

from The Collaborative International Dictionary of English v.0.48

Clasp \Clasp\, n.
   1. An adjustable catch, bent plate, or hook, for holding
      together two objects or the parts of anything, as the ends
      of a belt, the covers of a book, etc.
      [1913 Webster]

   2. A close embrace; a throwing of the arms around; a
      grasping, as with the hand.
      [1913 Webster]

   {Clasp knife}, a large knife, the blade of which folds or
      shuts into the handle.

   {Clasp lock}, a lock which closes or secures itself by means
      of a spring.
      [1913 Webster]