DOGLEG STAIRS

Abstract: The invention relates to a dogleg stairs construction comprising a stairs run (1) as well as a landing (2) forming an extension for it. For reducing the space required by the stairs, the uppermost step (8) of the stairs run is displaced under the landing and the nose of the landing is notched (5) according to the stair pattern. In the inner edge, the notching is decreased to an inner turn point (A') for maintaining the stair pattern on the side of the inner curve.

Description: Dogleg stairs The invention relates to a dogleg stairs comprised of at least a stairs run as well as of a 90° landing forming an extension for it. Said dogleg stairs is conventionally constructed in such a way that the stairs run is extended close to the nose of the landing, whereby the rear edge of the uppermost run step is essentially in the same vertical plane as the nose of the landing, but one step-riser below it. However, a detrimental feature of said construction is the need of space required by it. The "tread-depth" of the landing, i.e. its dimension from the nose to the op¬ posite edge is usually the same as the width of the stairs run extending from the landing. This dimension is essentially larger than the tread-depth dimension of the stairs runs. As an alternative construction for the said dogleg stairs is in fact usually used the spiral stairs, which from the point of view of the space required is more advantageous. However, this construction has its own disadvantages, one of which is essentially a decreasing tread-depth from the outer curve toward the inner curve. The object of the invention is to decrease the space re¬ quired by the said dogleg stair unit, whereby the const- ruct-ion is very competitive against the spiral stairs from the point of view of the space required without the detriments related thereto. According to the invention the said saved space for the stairs construction is taken from the landing in such a way that the head of a stairs run preceding at least one landing of the stairs construction is displaced, with respect to the inner turning point of the landing, essen¬ tially by the tread-depth dimension of the run under the landing in the tread direction of the stairs run, and that the nose of the landing is notched essentially cor¬ responding to the displacement, which notching is extend¬ ed by its full depth from the outer edge of the landing to a distance from the inner edge corresponding to the notching depth, as well as directed therefrom toward the inner turning point. The invention is described on the basis of an embodiment related to the accompanying drawing figures, which embo¬ diment is not intended to limit the patent protection defined in the patent claims. In the enclosed drawing Fig. 1 shows a stairs seen from the top, Fig. 2 shows the stairs seen from the side, Fig. 3 shows the fastening of the head of a stairs stringer to the landing, Fig. 4 shows the fastening of a stair step to the stairs stringer seen on the step plane, and Fig. 5 shows the fastening according to Fig. 4 seen from below. The stairs shown in the Fig. 1 and 2 contains a first stairs run 1, a first landing 2, further a second stairs run 3, a second landing 6 as well as a third stairs run 7. The invention is illustrated essentially by means of a basic unit formed by a run and a landing following it. As perhaps is best illustrated in Fig. 2, the head of the first stairs run 1 is displaced under the following landing 2. This requires, as shown in Fig. 1, that the nose of the stairs landing 2 be notched for achieving a continuous step pattern. The depth of the notching of the nose of the landing 2 is essentially the same as that by which the uppermost step 8 of the stair run 1 is underneath relative to the landing, i.e. the same as the tread-depth of the stair run. The notching is extended from the edge on the outer side of the landing by its full depth dimension near the inner curve point A' of the stair unit. The notching is exten - ed towards the inner edge essentially to a distance measured from the inner edge and corresponds to the depth of the notching, from which distance the notching is es¬ sentially directed to the inner curve point, i.e. the notching is decreased to the original front edge of the landing. The reason for decreasing this notching is the forming of a step area in the area of the inner curve in such a way that when coming from the next stairs run 3 following the landing 2, it is not possible to directly enter the uppermost step 8 of the first stairs run. The decrease of the notching can be performed rectilinearly according to Fig. 1, or alternatively as convex or conca¬ ve or other curve forms. As mentioned above, the applica¬ tion primarily describes a basic unit formed by a stairs run and a landing following it. These units can be com- bined according to the applications desired, and the turn direction can be varied according to the application de¬ sired. It is further to be taken into account that the under- swing of the stairs run and the landing following it does not necessarily have to be of the same dimension as the tread-depth, but it can be considerably smaller than that, if the circumstances so allow. In some special ca¬ ses, an underswing greater than the tread-depth can be considered, as much as about one and a half times the tread-depth. However, these greater underswings are used in especially narrow spaces, since the solution is con¬ nected with a partial discontinuity problem in the step pattern on the side of the inner curve of the stairs. It has frequently been observed that when the stairs con- struction, described above and requiring less space in comparison with a conventional dogleg stairs constructi¬ on, is installed, the space reserved for the stairs does in practice not correspond to the dimensioning accurately desired. Said factor has caused problems in the installa- tion of prefabricated stairs, and in some cases also an unsatisfactory working result because of installation borings, notchings and the like made in the construction. These actions requiring installation adjustments have been facilitated by means of an additional feature, as shown in Fig. 3 of the invention. In accordance with this additional feature, the stringer 9 of the stairs is fas¬ tened to the lower surface of the landing 2 by means of two groove rails 10 and 11 forming with each other a notch locking. The groove rail 10 provided with a downwardly directed open groove is fastened to the upper end of the stringer 9, to the level of the top end of the stringer. One of the groove rails, the rail 11, is similarly fastened to the lower surface of the landing 2, the groove being up¬ wardly directed. The dimensions of the grooves in contact with each other have been selected in such a way that when the fastening of the groove 11 to the lower surface of the landing 2 is loose, the grooves can be mutually longitudinally slided, i.e. the upper end of the stringer can be horizontally pushed for support under the landing. Tightening the fastening of the groove rail 11 to the lower surface of the landing presses the upper surface of the groove rail 10 fastened to the stringer as well as the end of the stringer against the lower surface of the landing 2. The location of the upper end of the stringer can thus be adjusted in place relative to the landing 2 before locking the stringer in place. By means of the fastening, the construction can also be readily after¬ wards disassembled, when necessary. The installation solution of the steps and the landing adapted to the assembly and disassembly of the stairs is shown in Fig. 4 and 5. The fastening is based on a hook¬ like element 12, which is mounted on the groove 13 made on the lower surface of the step (or landing) and on a boring 14 located at its inner end. The hook-like ele¬ ment 12 essentially extends outside the end of the step by the thickness of the stringer 9. The protruding end of the hook-like element 12 is provided with a thread for fastening the end with a barrel nut to a corresponding boring made in the bridgeboard. The hook end of the ele¬ ment 12 is correspondingly fastened to the boring 14 of the step 8 by means of a plug made of plastic or a cor¬ responding material, in which plug the hook end is preli¬ minary embedded or which is provided with a suitable bo- ring for the hook end. It is preferable to slightly tilt the hook end in the tightening direction, e.g. about 15° for ensuring the gripping of the hook.

Claims: AMENDED CLAIMS [received by the International Bureau on 5 February 1991 (05.02.91); original claim 3 cancelled; other claims unchanged (2 pages)] 1. A dogleg stairs comprised of at least a stairs run (1) as well as of a 90° landing forming an extension for it, whereby the head of a stairs run (1) preceding at least one landing (2) of the stairs construction is displaced, with respect to the inner turn point (A' ) of the landing, under the landing in the tread direction of the stairs essentially by the tread-depth dimension of the step (8) of the stairs run (1), and that the nose of the landing (2) is notched (4) essentially corresponding to the dis¬ placement, characterized in that the notching (4) is ex¬ tended by its full depth from the outer edge of the land¬ ing to a distance from the inner curve edge essentially corresponding to the notching depth (5), as well as di¬ rected therefrom toward the inner turn point (A' ). 2. A dogleg stairs according to claim 1, characterized in that the decrease in the notching depth is realized rectilinearly. 3. A dogleg stairs according to claim 1 or 2, characte¬ rized in that the distance, by which the head of the stairs run (1) is under the landing (2) is the tread- depth of the stairs run (1), at the highest. 4. A dogleg stairs according to any of the preceding claims 1-3, characterized in that the distance, by which the head of the stairs run (1) is under the landing (2) is larger than the tread-depth of the stairs run (1) . 5. A dogleg stairs according to claim 3 or 4, charac¬ terized in that distance, by which the head of the stairs run (1) is under the landing (2), is about 10-150% of the tread-depth of the stairs run. 6. A dogleg stairs according to any of the preceding claims 1-6, characterized in that the head of the stringers (9) of one stairs run (1, 3, 7) is fastened to the following landing (2, 6) by means of interacting groove lists (10, 11) of which one is fastened to the stringer (9) and the other to the lower surface of the landing (2, 6). 8. A dogleg stairs according to any of the preceding claims 1-7, characterized in that the steps (8) are fastened to the stringers by means of a hook bolt barrel nut fastening (12; 15) extending through the stringers.

Inventors: RIIHIMAEKI JUHA, RIIHIMAEKI, JUHA
Applicants: RIIHIMAEKI JUHA, RIIHIMAEKI, JUHA
Application year: 1990
Main classification: E04F11
IPC codes: E04F11