Locking system for a double hung window

A mounting and locking structure for a sash of a double hung window, said sash being movable in a planar path relative to a window frame, comprising:

• a jamb liner securable to a window frame and extending in a longitudinal direction adjacent one side of the window sash, said liner defining a guide track for said one sash side during planar movement of the sash relative to the frame;
• and
• means for selectively biasing said jamb liner against said sash side, wherein said biasing means includes
• a first cam secured between the frame and liner;
• and
• a second cam movable between the frame and liner and cooperating with the first cam to selectively adjust the spacing between said frame and said liner.

An apparatus for selectively securing a window sash to a window frame, comprising:

• a longitudinally extending jamb liner secured to said frame adjacent one side of the sash;
• means for selectively exerting a force between the frame and the liner in a lateral direction relative to the longitudinal direction of the liner said exerting means being selectively adjustable for adjusting the spacing between the frame and the liner to bias the liner into securing engagement with the sash, said exerting means including
• a first cam secured relative to the frame and liner;
• and
• a second cam movable between the frame and liner cooperating with the first cam.

An apparatus for selectively securing a window sash to a window frame, comprising:

• a longitudinally extending jamb liner secured to said frame adjacent one side of the sash;
• means for selectively adjusting the spacing between the frame and the liner in any position of the sash relative to the frame;
• and
• frictional locking surfaces on said liner and said sash whereby the adjusting means selectively increase the spacing between the frame and the liner to bias the liner surfaces against the sash surfaces to frictionally lock said sash against movement relative to said liner.