Stringer module for self-supporting stairs

Abstract

A stringer module for a self-supporting modular stairway in which each riser is composed of two modules (A), each module being manufactured from sheet metal, each module having an L-shape defining a base portion and a riser portion located at a first side of the base portion, whereby an overlap of the riser portion with an opposed part of the base portion of an adjacent like module defines a vertical riser of said stairway and the remaining base portion its tread. The riser portion is located above the base portion, the plane of the riser portion is folded to be offset relative to the base portion such that the base portions of adjacent modules are coplanar when overlapped. The overlapping portions of each module are provided with a series of horizontal slots on one portion and corresponding series of holes on the other portion, adjacent modules being secured in overlapping position by means of retractable pin-keys (B) engaging the holes and slots. The arrangement of slots and holes is such as to allow an adjustable positioning of the overlapping modules in both horizontal and vertical directions.

1 . A stringer module for a self-supporting modular stairway in which each riser is composed of two spaced-apart modules (A), each module being manufactured from sheet metal or an extruded aluminium alloy, each module having an L-snape of equal thickness defining a base portion and a riser portion located at a first side of the base portion, whereby an overlap of the riser portion with an opposed part of the base portion of an adjacent like module defines a vertical riser of said stairway and the remaining base portion its tread,
 characterised in that   the riser portion is located above the base portion, the plane of the riser portion is folded to be offset relative to the base portion such that the base portions of adjacent modules are coplanar when over-lapped, the overlapping portions of each module are provided with a series of horizontal slots on one portion and corresponding series of holes on the other portion, adjacent modules are secured In overlapping position by means of retractable pin-keys (B) located in said holes and cooperating with said slots, the arrangement of slots and holes being such as to allow an adjustable positioning of the overlapping modules in both horizontal and vertical directions, and the overlapping modules are locked together by means of fastening screws (D) and washers (C).   
     
     
         2 . Structure according to the preceding claims, characterised in that the folding is made towards the inner the structure itself and in the upper part of the lateral side. 
     
     
         3 . Structure according to  claim 2 , characterised in that the a riser portion, located at a first side of the base portion of a module, overlaps in a base portion of next module. 
     
     
         4 . Structure according to the preceding claims, characterised in that on the outer upper part are located the blind holes precision slots for the adjustment of the characteristic parameters. 
     
     
         5 . Structure according to  claim 4 , characterised in that on the inner bottom part of the lateral side are located the blind holes, for adjustment according to the regulations in force, of the structure thereof. 
     
     
         6 . Structure according to  claim 1 , characterised in that the pins-keys are in Steel. 
     
     
         7 . Structure according to  claim 1 , characterised in that the washers are in Steel. 
     
     
         8 . Structure according to  claim 1 , characterised in that the fastening screws are in Steel. 
     
     
         9 . Structure according to  claims 1 ,  4  and  6 , characterized in that the pins-keys are applied in two blind holes on the Inner lower part of the lateral side and coupled with the relating precision slots on the outer upper part of the next lateral side. 
     
     
         10 . Structure according to  claims 1 ,  5  and  6 , characterised in that the fastening screw is applied in the Inner part of the module and with the washer locking the two lateral sides together in the oval hole, positioned in the upper part of the module.