Abstract: A mechanism for latching a rotary shaft for, for example, a lift door, provided with a control arm connected to the rotary shaft and pivotally coupled by means of a coupling piece to an operating arm which is rotatable about a fixed shaft, coupling piece and operating arm being brought into line with each other for the latching of a rotary shaft, and a control mechanism being present for operating the latch. The operating arm bears a further shaft, upon which the control mechanism acts, and which can be actuated by a control unit, which can unlatch the mechanism while at the same time tensioning spring means, which on blocking of the rotary shaft are additionally tensioned, which additional tensioning still rotates the rotary shaft further when the blocking is removed, and in which the control unit can release the control mechanism, with the result that the spring means tensioned earlier will rotate the rotary shaft to the latched position.