Lock mechanism

An explosion proof lock mechanism for an enclosure, the lock mechanism comprising:

• a protrusion portion that is provided in one of a housing and a door, the door is configured to open and close a housing opening portion of the housing;
• a hook that is provided in the other one of the housing and the door, the hook configured to be rotatable around a rotation axis, the hook is engageable with the protrusion portion when the hook pivoted to an engaging position, and the hook is normally disengaged from the protrusion portion by its own weight maintaining the hook in a disengaging position due to gravity;
• and
• a pressing portion that extends separately from the hook and the pressing portion is configured to press the hook when engaged by a vertically extending lock rod element,
• wherein the hook includes a hook side engaging portion that is configured to engage with the protrusion portion with the rotation axis interposed between a hook side pressing portion and the hook side engaging portion, where the hook side pressing portion is configured to cause the protrusion portion to engage with the hook side engaging portion by the hook side pressing portion being pressed by the pressing portion when engaged by the vertically extending lock rod element, and where the hook side engaging portion includes a first restricting portion that is configured to restrict the hook side engaging portion from coming-off the protrusion portion in a protruding direction of the protrusion portion after engagement with the engaging portion, and a second restricting portion that is configured to restrict coming-off in a direction intersecting the protruding direction of the protrusion portion after engagement with the engaging portion.