a base unit including a base member; and

a pivotable unit coupled to the base unit by a shaft non-rotatably fixed to the pivotable unit, the pivotable unit is pivotable between a closed position and an open position, wherein the base unit includes a housing enclosing a locking mechanism, the housing including an angularly disposed slot therein, the locking mechanism comprising

a rolling member disposed in the slot, and

a cam non-rotatably fixed to a perimeter of the shaft,

wherein when the rolling member is located at a bottom of the slot, the rolling member abuts the cam and blocks the cam from rotating, thereby blocking the pivotable unit from pivoting to the open position,

wherein when the rolling member is located at a top of the slot, the cam is free from the rolling member to allow the pivotable unit to pivot to the open position

wherein the locking mechanism further comprising a manual release configured to manually move the rolling member to the top of the slot, the manual release comprises a cylinder having a lobe extending approximately perpendicularly from one end thereof, and a sliding member resting on top of the shaft and pivotably connects to the lobe, the sliding member interacts with the rolling member such that when the sliding member slides forwardly, it raises the rolling member to the top of the top of the slot.