Abstract: A lock has a body for extending through the sash and frame of a closed window. A head attached to a first end of the body bears on the outside of the sash. A movable abutment attached to a second end of the body may be positioned (a) so as to bear against the inside of the frame when the window is latched or locked or (b) so as to be able to pass through a hole in the frame to allow the window to be opened. Optionally, the body may have a variable length. Optionally, a plug or seal may be provided in the frame to close a hole in the frame when the window is open. Optionally, the abutment may slide and rotate on a pin in a slot at the second end of the body. Optionally, the abutment may slide and rotate on a pin in a slot at the second end of the body. Optionally, a spring may be provided over the body which, in an extended position, extends across a portion of the abutment.

Abstract: A lock has a body for extending through the sash and frame of a closed window. A head attached to a first end of the body bears on the outside of the sash. A movable abutment attached to a second end of the body may be positioned (a) so as to bear against the inside of the frame when the window is latched or locked or (b) so as to be able to pass through a hole in the frame to allow the window to be opened. Optionally, the body may have a variable length. Optionally, a plug or seal may be provided in the frame to close a hole in the frame when the window is open. Optionally, the abutment may slide and rotate on a pin in a slot at the second end of the body. Optionally, the abutment may slide and rotate on a pin in a slot at the second end of the body. Optionally, a spring may be provided over the body which, in an extended position, extends across a portion of the abutment.