Latch for use in window constructions

A latch for use in window constructions of the horizontally or vertically sliding type wherein a window frame includes guide rails to permit reciprocal sliding movement of a sash in the window frame while the latch is cooperatively engaged with a slot in the guide rail, the sash being a rectangular sash adapted to receive the latch internally so that an end segment of the latch projects to engage the slot and the latch is manually operable from externally of the sash so that the latch may be released from its engagement to permit the sash to be pivoted away from the frame, the latch comprising:

• a flat latch base plate having a smooth flat top surface, a flat underside and opposed square ends with an upstanding boss which is transversely centered on each end region, each boss including a vertical bore which pierces the boss and the base plate, a longitudinal slot to permit the insertion of a compression coil spring from a front end of the underside of the base plate, said slot being located inwardly of the boss on that end of the base plate, a groove in the top surface of the base plate for receiving the spring, which groove is continuous with an inner end of the slot, and upstanding side walls disposed along longitudinal edges of the base plate on opposite sides of the groove, said sidewalls including inwardly protruding wedge-shaped portions along a respective top edge thereof;
• and
• an elongated latch bolt having an outer end with an angled face, an inner end and flat side surfaces, the latch bolt being longer than the base plate and at least as wide as the base plate on each of the outer end and the inner end, the bolt including a first and second spaced apart vertical opening for respectively accommodating the bosses on the base plate to permit limited reciprocal movement of the bolt on the base plate, the first and second openings including a narrow slot on a bottom surface of the latch bolt, the narrow slot having a vertical side wall with a height which is less than the height of the bosses, and a wider superimposed slot for slidably accommodating the head of a screw fastener driven through the vertical bore in the boss, said first and second openings being located such that the outer end of the bolt overhangs the base plate for engaging the slot in the guide rail of a window frame when the latch is installed in a window sash, the bolt further including a cavity for accommodating the spring, which cavity is located in the bottom surface of the latch bolt between the first and second openings, and further including an opposed recess in each side wall of the latch bolt for accommodating the upstanding side walls of the base plate, each recess including a rail for slidably accommodating the wedge-shaped portions of the side walls, whereby the wedge-shaped portions of the side walls engage the rails of the latch bolt when the latch bolt is pressed against the base plate, to slidably retain the base plate and the latch bolt together as a latch unit, and the latch unit is affixed to a window sash by a screw fastener driven through the vertical bore in each boss and into the window sash frame.