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(11) | EP 0 354 634 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Improvements in mortice latches |
| (57) A mortice latch which largely overcomes the problems of wear and breakdown in operation
comprises a casing consisting of a top case (2) and a bottom case (1); a latch bolt
assembly reciprocally mounted in the casing and comprising a bolt head (7), a bolt
lathe (8) and a bolt end-stop (9); a latch bolt follower (23), pivotally mounted in
the casing, and a return spring (33). The follower (23) has a first curved arm (25)
provided at its end with an arcuate surface (26) which is engageable with the latch
bolt end-stop (9) and a second curved arm (28) which is provided with a cylindrical
socket (29). A roller (31) is freely pivotally mounted in the socket (29) and the
return spring (33) is mounted on a shaft (32) which extends from the roller (31).
The shaft (32) extends through an aperture in a strip (17) projecting from the bottom
case (1) and one end of the spring (33), which takes the form of a coil spring, bears
against the strip (17) while the other end of the spring bears against a stop (34)
on the shaft (32). The engagement of the roller (31) in the socket (29) of the follower
provides a ball and socket type action and is such that very little wear takes place
and any that does is fully compensated. The latch bolt can still be operated even
in the event of failure of the return spring (33). A dead bolt assembly may also be
fitted to the mortice latch if desired. |