The second photo shows the optional 'throw off' device as represented by the
lever on the right with the circular window that has the word OPEN on it. It
is in the disabled position in this photo.
In these photos the throw off device is in the enabled position and clearly
shows through the time lock door window to warn the user that the throw off
device is enabled. Yale used two styles of throw off device, this being the
earlier and less common version where the OPEN flag shows through the door
window as opposed to its own
opera window on the model Quad M.
This video shows a demonstration o f Yale's throw off device.
The the case has a small opera window on the upper left hand corner where a
throw off flag of a different configuration from the one in the example above
would show. In the second photo the plug shows where the throw off device would
have been mounted. The plug appears to be an OEM installation so it is possible
that that the owner of this lock at a later time asked Yale to take the device
Quad K aka K4, c. 1920's. This example uses the standard 72 hour
duration 'L' sized movements. It is equipped with what the Yale catalog calls a
"throw off" device; an option that allows the user to hold the lock 'off guard'
even after the time locks have been wound. This is represented by the flag that
has the word OPEN on it. When the device is activated the flag will show through
the door window so the operator is aware it is disarming the lock. Even if the
lock is left on inadvertently, it will automatically be disabled when the time
locks go off guard. 8"w x 4 1/2"h x 2 3/4"d. Case #278, movement #49653, #49818,
##49819, #49820. file 247
Quad-K aka K4, c. 1920's. A smaller and rare version of the Yale
four movement using longer duration 96 hour "L" sized movements made by Seth
Thomas. Seth Thomas made replacement movements that fit the cases originally
designed for the E. Howard movements after Howard exited the time lock business
in 1902. Another example of the longer duration option can be seen in the
Diebold examples. 8"w x 4
1/2"h x 2 3/4"d. Case #none, movement #55005, #55508, ##55569, #55816. file 100b