|
US2948299A
|
|
Detector unit valve construction
|
|
US2965732A
|
|
Detector unit switch construction
|
|
US2996652A
|
|
Battery charging and supervisory apparatus for closed circuit alarm systems
|
|
US2938197A
|
|
Automatic alarm transmitter
|
|
US2842758A
|
|
Detector unit
|
|
US1983740A
|
|
Thermostat
|
|
US1962926A
|
|
Electric gong
|
|
US1795843A
|
|
Alarm signal apparatus
|
|
US851775A
|
|
Electric attachment for tanks.
|
|
US845894A
|
|
Thermostat.
|
|
US792237A
|
|
Automatic alarm and controller for sprinkler-tanks, &c.
|
|
US800472A
|
|
Alarm system.
|
|
US667728A
|
|
Talking-machine.
|
|
US667727A
|
|
Automatic alarm system.
|
