This application relates to an attic access unit with folding stairs, which are unfolded downstairs to the room below the attic, and folded inside the frame, where the frame is used for mounting the attic access unit on the building slab.

State of the art. There is known solution of attic access unit with folding stairs from document FR2770550A1. Said attic access unit comprising a frame, hatch and stairs supported on artiulated lever device in the frame. The articulated lever device comprising two parallel articulated levers connected to the frame and to other articulated lever which connect those parallel levers with the hatch. Furthermore one of the parallel lever is connected with the hatch by another articulated lever attached to said parallel lever on its middle height such that said hatch support is adjustable in relation to the frame in closed hatch position. The artiulated lever device can be offset in a row of a mounting holes located on the frame such that the position of the hatch can be adjusted depending on the user requirements.

Disclosure. An attic access unit comprising a slab mounted frame and a hatch covering the frame from underneath. The hatch is supported by at least a single pair of swivel joints, which forms a four - bar linkage with the hatch and the attic access unit, where the means of hatch support is adjustable in relation to the frame in closed position. The attic access unit comprises the folding stairs, specifically pull-down stairs with hinged joints, scissor stairs or other type of stairs.

One embodiment of the attic access unit comprises folding stairs with hinged joints, the folding stairs are rotatably mounted in the frame, and the hatch is fixed to the top section of the folding stairs with two pairs of swivel joints. At least one pair comprises swivel joints joined with the frame with rotatably mounted adjustable length bars. The stairs are rotatably mounted in the frame, and a top section of folding stairs comprises a main axis seated in the bearings of the top section of folding stairs. Preferably, the main axis has the first pair of fixed arms directly at the frame, and each arm cooperates with a swivel joint of the means of hatch support with adjustable length bar. The adjustement, in the bar length of the connection of the one pair of the swivel joints with said bar allows for adjustment of the hatch position in vertical direction, and since the bars are installed on both sides of the unit, the adjustment also allows correction of the hatch position in lateral direction.

The swivel joints of the first and second pair have spacers in the joints between the arms and the top section of stairs to adjust horizontal position, lateral to the stairs. Horizontal adjustment along the stairs is provided by the fixtures in oval holes, sliding in relation to the hatch, with fasteners fixing the fixtures to the hatch.

In the second embodiment, the hatch is supported directly by the frame with two pairs of swivel joints, forming a four-bar linkage with the hatch, where the connection of the bar with one swivel joint from each pair of the swivel joints is adjustable in the bar length. Folding stairs are mounted on the top surface of the hatch. Folding stairs comprise a set of hinged sections, where the top section is mounted on the hatch and its position in relation to the hatch does not change during operation. Folding stairs further include scissor type mechanism with two parallel pantographs joined with treads. Scissor stairs are rotatably mounted on the top edge of the hatch and joined with flat bars rotatably mounted on the bottom edge of the hatch. Flat bars in folded position are positioned in the direction of the rotary joint in the top section of stairs and the hatch, and in unfolded position are positioned diagonally downwards, along the stairs.

Embodiments. The attic access unit with folding stairs of the present invention shown as embodiments in the following drawings, where the following figures shows:

• Fig. 1 - Attic access unit comprising the frame, three - section folding stairs supporting the hatch - axonometric view.
• Fig. 2 - Attic access unit of Fig. 1 in closed position (diagram with a single segment of folding stairs) - longitudinal section.
• Fig. 3 - Attic access unit of Fig. 2 in the initial opening stage - longitudinal section.
• Fig. 4 - Attic access unit of Fig. 2, completely open, with unfolded stairs (top and part of a middle section) - longitudinal section.
• Fig. 5 - Swivel joint (first pair - cooperating with adjustable length bar) with the arm of the main axis of folding stairs - top view.
• Fig. 6 -Swivel joint (second pair) with the top section of folding stairs - top view.
• Fig. 7 - Sliding fixtures (for hinged joint) to the hatch - longitudinal section.
• Fig. 8 - Frame with hatch and hinged mechanism with adjustable rotation axis joining the hatch with the frame - longitudinal section.
• Fig. 9 - Hinge with adjustable rotation axis of Fig. 9, in closed hatch position - axonometric view.
• Fig. 10 - Hinge with adjustable rotation axis of Fig. 9, in open hatch position - axonometric view.

Embodiment 1. - Figs. 1 to 7. Attic access unit with the hatch supported by the folding stairs, rotatably mounted in the frame. Main parts and components of the attic access unit: frame 1, folding stairs 2, comprising: top section 21, main axis 22, main axis arm 23; hatch 3, hinged joint, first pair 4, adjustable bar 41, hinged joint, second pair 42, spacers 43, sliding fixture 44. The attic access unit of the first embodiment is a fire rated unit comprising a box type hatch lined with fire resistant and low thermal conductivity material and with an intumescent seal inside the frame in a closed hatch position. Embodiment 2. - Figs. 8 to 10. Attic access unit with the hatch supported by the frame with stairs mounted on the hatch.

Main components and parts of the attic access unit: frame 5, hatch 6, adjustable hinge 7, flat bar 71, adjustable bar 72, fixed fixture 73, sliding fixture 74.The hatch comprises pull-down stairs or scissor stairs (not shown in the figure), with standard joints that are well known from existing solutions.