| 摘要 |
A security lock for a double-hung sash window assembly which is to be mounted in a stile of a sash frame to limit movement of a lower sash frame relative to an upper sash frame. The lock includes a casing adapted to be mounted within a recess formed in the upper sash frames, and a faceplate on the casing having an opening therein communicating with an interior casing cavity. A tumbler pivots in the cavity and is spring biased by a leaf spring to normally project through the opening to engage the lower sash in a locking position. The leaf spring is mounted completely within the casing cavity normally to bias the tumbler into its extended, locking position, but permitting the tumbler to be completely retracted within the casing cavity so that the lower sash frame can be raised and moved past the tumbler. The tumbler and casing wall include interlocking protrusions to prevent over-rotation of the tumbler during engagement with the lower sash frame. The lock can be supplied as an assembled unit for installation.
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