US3791485A

US3791485A - Mountable staircase, ladder or the like

Info

Publication number: US3791485A
Application number: US00190707A
Authority: US
Inventors: L Norlander
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-10-20
Filing date: 1971-10-20
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12

Abstract

A mountable staircase or ladder comprises at least two elongated beams and a plurality of treads, which are pivotally connected to each other by means of links, adapted at the ends of the treads and connecting the front portion of one tread with the rear portion of an adjacent tread, at least some of said links having extended portions, serving as support posts for arm rests and said treads being also provided near their ends with openings for the beams, said openings having a dimension in the length direction of the tread, which is approximately equal to the corresponding dimension of the beam, its dimension prependicular thereto however exceeding the corresponding dimension of the beam. At least the extended link portions are preferably removable and may be shifted from one side of the ladder to the other.

Description

United States Patent 1191 Norlander 14 1 Feb. 12, 1974- 1 MOUNTABLE STAIRCASE, LADDER OR Primary ExaminerReinaldo P. Machado THE LlKE [76] Inventor: Lars Ake Wilhelm Nor-lander, 9

Skogsliden, Stocksund, Sweden 1571 ABSTRACT [22] Fi d; O 20, 1973 A mountable staircase 0r ladder comprises at least two elongated beams and a plurality of treads, which are [2]] Appl' l90707 pivotally connected to each other by means of links, adapted at the ends of the treads and connecting the 52 us. Cl 182/106, 182/156, 182/194, front portion of one tread with the rear portion of an 132/228 adjacent tread, at least some of said links having ex- 51 Int. Cl. 1306c l/38 tended portions, serving as pp Posts for arm ram [58] Field of Sea h 182/156 41 228 194 195 and said treads being also provided near their ends [56] References Cited UNITED STATES PATENTS 2,269,364 1/1942 Farrand 182/41 2,812,528 11/1957 Odell 182/156 3,085,651 4/1963 Rich 182/228 with openings for the beams, said openings having a dimension in the length direction of the tread, which is approximately equal to the corresponding dimension of the beam, its dimension prependicular thereto however exceeding the corresponding dimension of the beam. At least the extended link portions are preferably removable and may be shifted from one side of the ladder to the other.

6 Claims, 3 Drawing Figures mam En 1 231914 3, 79 1 485 INVENTOR L/ms AKE WILHEL/M NORLHNOER BY m zw ATTORNEY MOUNTABLE STAIRCASE, LADDER OR THE LIKE This invention refers to a mountable staircase, ladder or the like, preferably intended for temporary use.

Staircases and ladders used in housebuilding are difficult to transport between different building yards owing to the fact that they are quite bulky. Frequently damages occur during such transports as the ladders are transported together with construction material of different kinds. In order to avoid loading, transport and storage of assembled staircases and ladders it is therefore common practice to make them in the building yard. After having been used such ladders are disassembled and the parts are transported to another building yard. The staircases and'ladders will consequently be assembled in a temporary and provisional way by nailing which in turn leads to accident risks owing to lacking rigidity in the construction.

The main purpose of the invention is to provide a mountable staircase or ladder, which has an arm rest and which may be easily assembled to a,rigid unit as well as it may be easily and rapidly disassembled to a compact unit, easy to transport and store.

The invention will now be described more in detail with reference to the accompanying drawing in which FIG. 1 is a perspective view of a ladder or staircase according to the invention in its assembled condition.

FIG. 2 is a horizontal section through one of the treads and FIG. 3 is a plan view of the tread shown in FIG. 2.

The treads, designated 1 respectively 1', consist of extruded profiles made from aluminium, plastic or similar material. The longitudinal edge portions of said treads are in the shape of cylindrical fittings 2, 2' receiving rods 3, 3' the length of which exceeding the width of the treads. The portions of the rods which project outside the tread serve as pivots for links 4, 4' which connect the rear end of a lower tread with the front end of a tread, situated thereabove. The ends of the rods are threaded for co-operation with nuts. Some of the links, 4', are extended for a purpose to be described. Each tread is near each of its end portions provided with a rectangular opening 5, 5' through which the side beams 6, 6 of the ladder may be introduced. The length of said openings is such that said beams may take an inclined position as clearly shown in the drawing, while their width approximately corresponds to the width of the beam in question. The treads l, 1' may be provided with a plurality of mutually parallel ridges 7, 7 intended to make the ladder slip-free and they may also have openings 8, 8' for letting through rain, snow and the like. The uppermost of the treads may at its end portions be provided with attachment plates 9 provided with holes for screws by means of which latter said uppermost tread may be secured to the beam 6, 6 which is preferably made from wood.

Owing to the fact that the links 4, 4' are diagonally pivoted to the ends of two adjacent treads the treads and the links together form a unit that may be folded together into a compact unit, easy to transport and store. Of course, this folding only can take place when the beams 6, 6' are removed from the treads. From this storage and transport condition in which the beams are separated from the folded tread-and-link unit the ladder is easily and rapidly assembled in that the beams are introduced into the

openings

5, 5 whereupon the treads l, 1 are displaced in direction away from each other until the short edges limiting the openings 5, 5' come into contact with the front and rear edges of the beams. When the ladder is loaded, for instance by a person climbing the ladder, the treads are locked relative to the beams in that said short edges, limiting the openings, are pressed into the wood material at the front portion of the ladder while the links 4, 4' support the rear portions of the treads. Said treads are thereby automatically secured to the side beams as also the higher situated treads are secured to the side beams owing to a pulling action transmitted by the links 4, 4. In order to secure the treads such that the ladder may be transported also in an unloaded condition the uppermost tread is preferably secured to the side beams by means of screws through the holes of the attachment plates 9.

The longitudinal edge portions of the treads are obliquely directed relative to the plance of the treads wich gives the treads the desired rigidity at the same time as the links receive a good seat against the ends of said edge portions. The bolt 3, 3' also add rigidity to the treads.

As shown in FIG. 1 the links 4' are longer than the links 4 and provided with holes for screws 10 and 1 1 by means of which an arm rest in the shape of a lower rail 12 and an upper rail 13 may be secured to said links. In this manner a ladder or staircase suitable for housebuilding purposes is established. The arm rest may be shifted from one side of the ladderto the other merely by removing the extended links 4' and the links 4 on the opposite side of the ladder and shifting them. It is of course also possible to substitute for the extended links 4' another link construction which in addition to the extended links 4' comprises inner links, having the same length as the links 4 but being provided with means for securing the extended links 4 outside to said inner links. The shorter links are permanently connected to the treads by means of the rods 3, which means that only the longer links have to be shifted when the arm rest is to be shifted from one side to the other and the ladder or staircase will not collapse during such shifting. Of course, it is also possible to arrange for arm rests at both sides of the ladder or stair case.

I claim:

1. A mountable staircase or ladder, comprising at least two elongated beams, forming the side beams of the staircase or ladder, and a plurality of elongated treads, each having near each of its ends an opening through which the corresponding side beam may be introduced, said opening having in the length direction of the tread a dimension, approximately equal to the corresponding dimension of the beam introduced therein, its dimension perpendicular to said length direction however exceeding the corresponding dimension of the beam, said treads being foldably connected to each other by means of links adapted at the ends of the treads and connecting the front portion of one tread with the rear portion of an adjacent tread, at least some of said links having extended portions forming supporting posts for elongated bars, parallel to the beams and serving as arm rests.

2. A mountable staircase or ladder as claimed in claim 1 having the longitudinal edges of the treads in the form of fittings for receiving rods, projecting outside the tread, the projecting portions serving as pivots for the links.

5. A mountable staircase or ladder as claimed in claim 1, the extended portions forming the supporting posts for the arm rests being integral with the links.

6. A mountable staircase 0r ladder as claimed in claim 1, the extended portions, forming the supporting posts for the arm rests being in the form of rails, removably connected to shorter links.

Claims

2. A mountable staircase or ladder as claimed in cLaim 1 having the longitudinal edges of the treads in the form of fittings for receiving rods, projecting outside the tread, the projecting portions serving as pivots for the links. 3 A mountable staircase or ladder as claimed in claim 1, the treads being in the form of extruded profiles having a plan step plate and inwardly and downwardly sloping front and rear edges, terminating in cylindrical fitting portions.

4. A mountable staircase or ladder as claimed in claim 1, at least the links having the extended portion being removably connected to the treads.

6. A mountable staircase or ladder as claimed in claim 1, the extended portions, forming the supporting posts for the arm rests being in the form of rails, removably connected to shorter links.