Abstract: A door lock comprising a block having a slot into which a locking arm moves when the door is shut. A pivot arm is resiliently biassed to extend into the slot and, a separate locking element is resiliently biassed to slidably extend into the slot. While a rotatable element is resiliently biassed to rotate clockwise to bring a roller directly under the locking element, the pivot arm abuts the roller and is itself resiliently biassed to prevent the roller from reaching a position fully under the locking element. Entry of the locking arm into the slot depresses the pivot arm forcing the locking element downward to permit full entry of the locking arm into the slot. As the locking element descends, the roller is urged counter-clockwise and the locking element engages a channel in the locking arm. The depressed pivot arm will not abut the roller at this point thereby allowing it to reach a position fully under the locking element which locks the locking element in the locking arm channel.