Abstract: Lock including at least one latch (2) which can move against a spring (8) between a locked position and a retracted position, this displacement of the latch taking place against the spring which thus passes from a position known as the rest position to a position known as the tension position, this also including a means (6, 7) for holding the spring (8) in its so-called tension position, and a means (17) actuated by the keeper when it engages with the latch and actuating this holding device so as to release the spring, the lock being characterized in that it includes a means (26) actuated when the door is being opened so as to play a part in tensioning the spring (8).