US1655769A - Stair structure - Google Patents

Description

Patented Jan. 10, 1928.

UNITED STATES 1,655,769 PATENT OFFICE.

MORRIS LERNER, OF CHELSEA, MASSACHUSETTS, ASSIGNOR TO A. L. SMITH IRON VJ'ORKS, OF CHELSEA, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

STAIR STRUCTURE.

Application filed September 26, 1925. Serial No. 58,817.

.This invention pertains to stair structures and more particularly to structures of that type in which forms made of sheet material, for example, sheet steel, and each comprising a tread and a riser portion, are assembled to make the stair structure, the sheet metal tread portions of the forms usually supporting treads proper consisting of concrete, wood, rubber or the like which are clamped to or interlocked with the form.

Commonly the tread and riser portion of the form are integrally united at the rear angle of the stair and adjacent forms are attached to one another by bolts, rivets or the 15 like at the forward angle or nosing of the stair.

' In order to provide a suitable pocket or receptacle for the concrete filler or other tread proper of the stair, it is customary to extend the upper part of the riser above the level of the tread of the next higher form so as to provide what may be termed a nosing flange, but while the desired receptacle for the concrete tread is thus provided, the upwardly extending nosing flange of the riser is a constantsour ce of annoyance and danger since it is very difficult to anchor it rigidly in position and as soon as the concrete begins to wear, this upwardly projecting nosing flange is exposed, constituting a menace to the safety of the user. Since this nosing portion is subject to rapid wear it is desirable that it may be replaced readily, but in the usual construction such replace ment of the nosing portion or the attachment of a wear plate at this point is extremely diflicult since the space immediately to the rear of the nosing is completely filled with concrete which cannot easily be drilled and which will not hold screw threads.

The riser supports the load applied to the rear part of the next tread below and the connections uniting it to the next tread above are thus called upon to sustain this load. Since in the usual construction these con nections are relatively few in number the riser frequently pulls away from the tread next above to such an extent as to elevate the nosing flange of the riser above the level of the concrete surface and to produce cracks in the concrete adjacent to the nosing.

Moreover, with usual constructions two or more workmenare required to assemble the stair forms and in some arrangements van aasiliary arrangements in additioiit i the tread and risers must be prepared, carried in' stock by. the manufacturer, and htandled by the workmen in assembling the s am The principal object of the present invention is to provide a stair structure having great strength and durability and in which the nosing of the stair is unusually strong and wear resistant, provides additional stiflness to the stair structure as a whole, and is capable of ready renewal when worn; to provide a structure wherein the tread and riser are integrally united at the nosingso that the tread and riser cannot separate at this point; to provide a structure wherein ample provision is made for interlocking the concrete or other tread proper with the metal parts and wherein wear of the concrete will not expose dangerously sharp portions of the metal sub-structure; to provide a structure of such character as to permit ready assemblage of the parts by a single workman; and to provide a form having a riser of great strength, considering the material employed and which is adapted to form a sanitary angle with the treads next below.

In the accompanying drawings in which a preferred embodiment of the invention is illustrated, by way of example:

Fig. 1 is a longitudinal sectional View of a portion of a staircase embodying this invention;

Fig. 2 is asection on the line 22 of Fig. 1;

Fig. 3 is a perspective view of a portion of one of the improved stair forms;

Fig. 4 is a view similar to Fig. 1 showing a modification of the invention;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a view similar to Fig. 1 showing stilil another modification of the invention; an

Fig. 7 is a fragmentary vertical section to large scale showing the application of a wear plate to the nosing.

Referring now to the drawings in detail, 1 denotes stringers consisting of channels to which are bolted or otherwise fastened angle irons or carriers 2. These angle irons form the immediate supporting means for the stair forms 3.

Each form 3 comprises a riser portion 4 and a tread portion 5 integral therewith. Atthe juncture of the riser and trad I pro ride a nosing 7 of substantially U or channel shape. Thisnosing rises appreciably above the level of the tread and the rear wall 8 of the nosing preferably inclines downwardly and forwardly so that the nosing and tread meetin an acute angle. The rear edge portion 9 of the tread is bent upwardly and forwardly to form an angle, preferably acute,

. with the main body of the tread. The lower 'with the holes 13 and 1 1 alined.

other fastening means passes through each pair ofthese holes and also through the angle iron 2 supporting the tread.

'l'i hen the forms are assembled,concrete I 15 is placed upon the treads. The parts 8 of the nosing and 11 of the riser together with the tread form a pocket or mould trapezoidal in front to rear section for the reception of th'e'concrete, and the concrete when set is locked in place by reason of the upward convergence of parts 8 and 11. As will be seen in Fig. 1, the rearward slope of part 10 provides an obtuse angle between the concrete surface and the riser and this makes for increased sanitation since the stairs are easier to clean and there are no cracks for the'dirt to collect/in. 7 I

The arrangement thus far described provides a stair whose metal parts are integrally connected at the nosing so that there is no possibility of their pulling-away from each other with consequent exposure of edges which may be dangerous to the user, whileat the same time furnishing a maximum strength at'the point where it is most desired; Moreover since the flange 9 of the tread is disposed at-the rear side of the lower part 11 of the next'riser, the latter is locked in "position so that it cannot be driven rear wardly by the impact of the feet of the user and the stair is greatly strengthened in a front to rear direction by this hook-like interengagement of the parts. Moreover,

the shape of the stair form is such that the concrete tread is firmly locked in position, while the double angle at the'lower part of the riser furnishes great strength in a transverse direction.

The provision of the hollow channel-like nosing has a further advantage in addition to those which have heretofore been men tioned. As illustrated in Fi 7 a wear plate 30 may be secured to the top surface 7 of the nosing when the nosing becomes worn through long use. This wear plate may readily be secured in position by means of screws 31 passing down through threaded holes drilled in the upper member 7 of the nosing. As'the chamber 32 within the nosing is empty it is an easy matter to drill these holes and to tap them for the reception of the screws, whereas if the nosing overlay theconcrete tread such drilling and tapping would be a difficult and unsatisfactory operation- The wear plat 230 may, as shown, cover merely the top edge of the nosing or may havean extension upon its front edge overlapping the upper part of the riser. Figs. 1 and 5 illustrates novel form of angle iron which facilitates the assembly of the stairs. This angle iron '16 is notched in its upper or horizontal, flange and the metal from these notches is bent perpendicular to the horizontal flange of the angle'to form locking lugs 17 preferably of wedge-like form. These lugs areapertured as at'18 to receive locking wedge pins.19.: The lug s'l'i pass up through the holes 13. and let in the assembled stair formsl and the wedgepins 19 are inserted in the apertures 18 to lock the forms to' the angle irons and to each other. 1

The great advantage in this type of angle iron'lies in the fact that it requires but one man to assemble the stairswhereas in the construction shownin Figs. 1 to 3, it requires two men, one to manipulate the bolt and another the nut. i lViththisimproved angle iron all that isnecessary is to aline'the holes with the locking lugs and insert thewedge pins. i

In Figs. l and Gareshown two slightly modified types of stair forms- In both of these modifications the-bent-up portion-f the tread, as .hereinbefore described,- is eliminated, the tread terminating in a horizontal plane. fin-Fig. 1 the rear of the tread is slightly elevated-asat 20 so that the horizontal' portion 12 of the riser may be received between the tread and the corresponding angle iron or carrier2 In Fig.

6 the rear end of the carrier or angle iron 2 is depressed'as at 21 so as to receive the horizontal portion 12- of the riser between it and the tread. In both of these modifica= tions the tread is supported upon theriser. It will be observed that by eliminating the portion 9 a saving in material iseffeeted without asacrifice of strength. \Vhile the lugs 18 are herein shown as integral with the angle iron, they may obviouslybe made as separate elements and suitably secured to the angles.

I claim: 7

1. A stair structure-comprising a riser, a nosing of double thickness, a tread portion. integral with the riser, said nosing extending upwardly above the tread portion and'having its rear wall inclined forwardly lilil lll) and downwardly and the lower portion of the riser being inclined baclrwardly and downwardly whereby a cementitious filler poured upon the tread portion will tend to be locked in place by the rear wall of the nosing.

2. In a stair structure, a plurality of stair forms each comprising a substantially channel-shaped nosing, and a riser and tread integral therewith, the rear wall of said nosing inclining forwardly and downwardly, the riser having a substantially horizontal flange at its lower part and a forwardly and upwardly inclined port-ion adjacent to said flange, whereby when said stair forms are assembled, the tread and forwardly inclined wall of the nosing of one form together with the forwardly inclined portion of the riser of the form nextabove provide a pocket for the reception of a plastic filler, said pocket positively locking said filler to the first named form.

3. In a stair structure, stringers, carriers fastened to said stringers, and stair forms each comprising a tread and a riser, each riser having a forwardly directed flange at its lower edge, each tread being supported upon a carrier and having its rear margin slightly elevated to provide a space between said thread and its carrier for the reception of the forwardly directed flange on the riser.

4. In a stair structure, a carrier comprising an angle iron having upstanding lugs on one of its flanges, said lugs being provided with apertures for the reception of locking pins.

5. A stair structure comprising a carrier having a horizontal supporting member, a lug projecting upwardly from said supporting member, said lug being a transverse aperture, a pair of stair forms, each form having a part resting upon said supporting member, said parts having aligned apertures for the passage of the lug, and a wedge pin passing through the aperture in the lug and thereby locking the forms to the carrier.

Signed by me at- Boston, Massachusetts, this 24th day of September, 1925.

MORRIS LERNER.

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