Securitron UNL-24 UNLATCH - Manual (Page 5)

PN# 500-18300
Page 5 Rev. D, 08/11
FIG 5: UNLATCH VIEW FROM ABOVE IN REST (SECURE) POSITION
SPRING LATCH
DEAD LATCH
PIN
DEAD LATCH
PLUNGER
SPRING LATCH PLUNGER
DOOR FRAME
DOOR STOP
DOOR
IN THE REST (SECURE) POSITION, THE SPRING LATCH IS ALLOWED TO COME OUT BY THE SPRING
LATCH PLUNGER THEREBY SECURING THE DOOR. THE DEAD LATCH PLUNGER HOWEVER PUSHES
IN THE DEAD LATCH PIN WHICH "FREEZES" THE SPRING LATCH FOR BEST SECURITY.
FIG 6: UNLATCH IN OPERATION
SPRING LATCH
PLUNGER
DEAD LATCH
PLUNGER
DEAD LATCH
PIN
SPRING LATCH
SPRING LATCH
PLUNGER
DEAD LATCH
PLUNGER
DEAD LATCH
PIN
SPRING LATCH
IN THE FIRST OPERATIONAL STEP, THE DEAD LATCH
PLUNGER WITHDRAWS WHICH ALLOWS THE DEAD
LATCH PIN TO COME OUT. THIS "UNFREEZES" THE
SPRING LATCH FINALLY, BOTH PLUNGERS MOVE
FORWARD TOGETHER. THIS PUSHES OUT
THE SPRINGLATCH AND DEADLATCH PIN
AND THEREBY RELEASES THE DOOR.
Note that if the door is heavily pre-loaded (by someone trying to pull it open before the UnLatch
has released it for example), the UnLatch may not possess enough power to release the door.
This is termed a stall condition for the motor. When a motor is stalled for a period of time, it
can be damaged by heat build up as motors draw heavy current when they’re not permitted to
move. The UnLatch automatically detects any stall condition that persists for more than
1.5 seconds and shuts itself off. To operate, the UnLatch must simply be triggered again (which
is the normal action for anyone who has failed to enter) and it will operate normally.