Patent ID: 8807607
Filing Date: 2014-08-19
Classification: E05B,E05C,Y10T

Abstract:
1. In a window sash lock of the type having a housing adapted for mounting on an upper rail of a window sash and having a cavity therein, a rotatable locking member received in said cavity for rotational movement, an operating lever mounted at a top of said housing, passing through an upper wall of said housing and connected to said locking member underneath said upper wall for effecting rotation of said locking member, said locking member including a partially cylindrical detent cam rotatably engaged and supported by a partially cylindrical bearing portion associated with said housing, said partially cylindrical detent cam having opposed cylindrical surface portions separated by opposed recessed portions forming opposed detent surfaces, said partially cylindrical bearing portions comprising opposed arcuate bearing surfaces positioned to engage and rotatably support opposite sides of said partially cylindrical detent cam, said opposed arcuate bearing surfaces having an arcuate extent such that said rotary locking member is rotatably supported by said arcuate bearing surfaces in all rotary positions of said locking member, and a detent member acting in a space between said opposed arcuate bearing surfaces with a resilient force directed radially inward toward an axis of said partially cylindrical detent cam and positioned be bear against said detent surfaces to releasably retain said rotary locking element in predetermined “lock” or “unlock” positions, the improvement characterized by said detent member comprising a one-piece detent spring of closed configuration, having side elements and end elements defining an open center portion, said detent spring being formed of a resilient plastic material and having spaced-apart, opposed side elements and spaced-apart, opposed end elements integrally connected at ends thereof to respective ends of said side elements, said detent spring being positioned in surrounding relation to said partially cylindrical detent cam, said housing having locating walls, associated with said cavity, engaging and fixing the location of said detent spring with respect to said cavity and with respect to said partially cylindrical detent cam, said spaced-apart side elements having contact portions spanning the spaces between said arcuate bearing surfaces and resiliently engaging opposite outer surface portions of said partially cylindrical detent cam in said spaces, said side elements being configured in a normally inwardly bowed shape, with center portions thereof comprising said contact portions and positioned to engage said opposed detent surfaces when said detent cam is in said “lock” or “unlock” positions, said contact portions being outwardly resiliently displaced by said detent element from said inwardly bowed configuration to an outwardly bowed configuration during rotation of said detent cam between said “lock” and “unlock” positions and functioning, when not so resiliently displaced, to retain said detent element in said “lock” or “unlock” positions, said locating walls including wall portions positioned to engage surfaces of the end elements of said detent spring to limit outward separating movement of said end elements during outward displacement of the contact portions of said side elements.