Abstract: This invention relates to a stair assembly to be arranged in a stairwell opening of an upper floor, comprising: —a girder assembly; —a plurality of steps mounted to the girder assembly; and —a guard structure, wherein the girder assembly is pivotably mountable to the upper floor to pivot about a pivot axis between an operational position, in which the girder assembly extends obliquely downwards, and a hidden position, in which the girder assembly extends horizontally, wherein the moveable guard structure is moveable between an operational position, in which the guard structure extends upwards, and a hidden position, in which the guard structure has moved downwards, and wherein the stair assembly is configured such that when the girder assembly and the guard structure are in their respective hidden positions a person is able to walk over the stair assembly as part of the upper floor.

Abstract: This invention relates to a stair assembly to be arranged in a stairwell opening of an upper floor, comprising: —a girder assembly; —a plurality of steps mounted to the girder assembly; and —a guard structure, wherein the girder assembly is pivotably mountable to the upper floor to pivot about a pivot axis between an operational position, in which the girder assembly extends obliquely downwards, and a hidden position, in which the girder assembly extends horizontally, wherein the moveable guard structure is moveable between an operational position, in which the guard structure extends upwards, and a hidden position, in which the guard structure has moved downwards, and wherein the stair assembly is configured such that when the girder assembly and the guard structure are in their respective hidden positions a person is able to walk over the stair assembly as part of the upper floor.

Abstract: A single revolution mechanism is disclosed in which a feed roll is mounted on a print lever which is attached rotatably to a pivot. By rotating the lever, the feed roll can be brought into contact with an external driving shaft. The feed roll is coupled to a ratchet mechanism comprising a pawl and ratchet. The pawl is engaged with a spring urged pressure lever so that when the feed roll is driven, the ratchet pushes itself away from the second lever to latch the print lever and roll in the operative position during a full revolution. After performing the revolution, the print lever reengages the ratchet to unlatch the device from the driving roll in preparation for another actuation.