A latch including a housing having side members each having an elongated slot, a bolt mounted rotatably to the housing and positioned between the side members of the housing, an adjustment mechanism, and a pin and roller positioned slidably within the elongated slots of the side members of the housing. The adjustment mechanism includes a compression spring, a central cap for receiving the pin and roller therethrough, and a nut for adjusting the load on the compression spring. The bolt is moveable between a first, closed position, in which the pin and roller are engaged with the bolt, and a second open position, in which the pin and roller are disengaged from the bolt. The latch can be opened automatically when a defined load, as adjusted by the adjustment mechanism, is provided on the bolt to disengage the pin and roller from the bolt.

Methods of emergency opening of manholes in emergency situations, devices and systems for their embodiment and methods of assembling devices for emergency opening of movable elements installed in manholes.

A latch including a housing having side members each having an elongated slot, a bolt mounted rotatably to the housing and positioned between the side members of the housing, a trigger mounted rotatably to the housing, and a pin and roller positioned slidably within the elongated slots of the side members of the housing. The bolt is moveable between a first, closed position and a second open position. The trigger is moveable between a first position, in which the pin and roller are engaged with the bolt when the bolt is in its first position, and a second position, in which the pin and roller are disengaged from the bolt. The latch can be opened automatically when a defined load is provided on the bolt, or manually by depressing the trigger to disengage the pin and roller from the bolt.

A pressure relief latch includes a housing, a bolt, a cam, and a spring assembly. The housing includes a door panel, a first lateral panel, and a second lateral panel. The first lateral panel and the second lateral panel extend outward from the door panel. The bolt includes a bolt body and a roller bearing. The bolt body is pivotably mounted to the first lateral panel and the second lateral panel at a bolt pivot axis. The bolt body is pivotable about the bolt pivot axis between a latched position and an unlatched position. The roller bearing is rotatably mounted to the bolt body. The cam is pivotably mounted to the first lateral panel and the second lateral panel. The spring assembly is pivotably mounted to the cam. The spring assembly is configured to bias the cam toward the bolt.

An electronic lockset assembly is configured to determine whether or not a door is open or closed before the lockset actuates a bolt. In one aspect, a wireless electronic lockset is disclosed. The wireless electronic lockset includes a processing unit, a bolt movable between a locked position and an unlocked position, a motor actuatable by the processing unit to move the bolt between the locked and unlocked positions, and a sensor communicatively connected to the processing unit and configured to detect air pressure. The processing unit is configured to execute instructions to receive, from the sensor, air pressure signals, and determine whether a door is closed based at least in part on a change in the air pressure reflected in the air pressure signals.