A refrigerator includes a cabinet, a main door, an auxiliary storage compartment provided to a rear surface of the main door, and a sub-door. The main door is rotatably connected to the cabinet, and the sub-door is rotatably connected to the main door. An access opening is provided in the main door to allow access to the auxiliary storage compartment. The refrigerator also includes a button exposed at a front surface of the sub-door to receive input provided by a user, a hook member having a pivot shaft mounted to its rear end, and a locking protrusion provided in a groove located on a front surface of the main door that can selectively couple to the hook member. The hook member protrudes backward from a rear surface of the sub-door and can rotate within the sub-door about the pivot shaft in response to receipt of user input at the button.

A preload mechanism for an actuator is disclosed that includes a rotating element configured to rotate about a pivot. The preload mechanism also includes a bias element with a first end that is coupled to a second contact point of the rotating element and a second end configured to be pinned relative to the pivot. The bias element has a line of action extending from the second end through the first end. The line of action has an offset distance that is the minimum distance between the line of action and the pivot. The offset distance has a first value when the rotating element is in the first position and a second value when the rotating element is the second position, the second value being smaller than the first value.

A preload mechanism for an actuator is disclosed that includes a rotating element configured to rotate about a pivot. The preload mechanism also includes a bias element with a first end that is coupled to a second contact point of the rotating element and a second end configured to be pinned relative to the pivot. The bias element has a line of action extending from the second end through the first end. The line of action has an offset distance that is the minimum distance between the line of action and the pivot. The offset distance has a first value when the rotating element is in the first position and a second value when the rotating element is the second position, the second value being smaller than the first value.

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.

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.