Lock for sliding doors

Claim 1

A LOCKING DEVICE FOR A PAIR OF ADJACENT OVERLAPPING SLIDE TRACK PANELS COMPRISING A VERTICALLY ELONGATED HOUSING, MEANS FOR SECURING THE HOUSING TO ONE OF THE PANELS, SAID HOUSING HAVING AN OPENING THROUGH ITS OUTER WALL, A BLOCK MEMBER MOUNTED IN THE BOTTOM OF THE HOUSING AND PROJECTING THROUGH SAID OPENING FOR HORIZONTAL MOVEMENT BETWEEN OPEN AND CLOSED POSITIONS OF THE LOCKING DEVICE, A RIGID PIN SECURED TO THE BLOCK AND PROJECTING THROUGH AN APERTURE OF THE INNER SIDE OF THE HOUSING, A SPRING WITHIN THE HOUSING URGING THE BLOCK AND PIN TO A RETRACTED POSITION, A VERTICAL SLIDE WITHIN THE HOUSING HAVING AN UNDERCUT SLANT EDGE IN CONTACT WITH A CORRESPONDING PARALLEL SLANT EDGE OF THE BLOCK IN THE RETRACTED POSITION OF THE BLOCK SPRING MEANS URGING THE SLIDE DOWNWARDLY TO A POSITION OF ENGAGEMENT WITH THE BLOCK, RACK TEETH CARRIED BY THE BLOCK, A PAWL SECURED TO SAID VERTICAL SLIDE FOR ENGAGING THE RACK IN AN ELEVATED POSITION OF THE VERTICAL SLIDE, A FINGER INTEGRAL WITH AND PROJECTING OUTWARDLY FROM SAID VERTICAL SLIDE, SAID HOUSING HAVING A VERTICALLY ENLARGED OPENING THROUGH WHICH THE FINGER PROJECTS AND IN WHICH IT IS MOVABLE TO PERMIT MANUAL ENGAGEMENT AND VERTICAL ACTUATION THEREOF, SAID VERTICAL SLIDE HAVING AN EXTENSION AT ITS UPPER END PASSING THROUGH AN OPENING IN THE TOP OF THE HOUSING, SAID EXTENSION BEING SUFFICIENTLY LONG TO THE JUXTAPOSED IN RELATION TO A DOWNWARDLY FACING STATIONARY MEMBER WHEN THE VERTICAL SLIDE IS IN ITS UPPERMOST POSITION.