US3927518A

US3927518A - Site assembled multi-story stair

Info

Publication number: US3927518A
Application number: US501804A
Authority: US
Inventors: Smith H Simmons; Otho A William; Arthur E Miller
Original assignee: METAL SERVICE CO Inc
Current assignee: METAL SERVICE CO Inc
Priority date: 1974-08-29
Filing date: 1974-08-29
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23
Also published as: GB1496604A; BR7505518A

Abstract

A prefabricated multi-story, site assembled stair is disclosed in which the temporary supporting members are all confined within the stairwell and in which the platforms are pivotally mounted on the prefabricated stair unit for rocking movement between an unobstructed raised position to normal horizontal position to form the landing.

Description

[ Dec. 23, 1975 ABSTRACT United States Patent 1191 Simmons et a].

[ SITE ASSEMBLED MULTI-STORY STAIR 3,788,018 1/1974 Simmons et al.

[75] Inventors: Smith H. Simmons; Otho A.

William, both of Largo; Arthur E. v Miller, Tampa, all of Fla. [73] Assignee: Metal Service Company, Inc.,

Primary ExaminerJ. Karl Bell Attorney, Agent, or Firm-McDougall, Hersh & Scott Clearwater, Fla.

1 7 5 .l 9 l 9 4 0 1 l 0 A5 0 N mm. D. FA 1] 21 22 [.I.

References Cited UNITED STATES PATENTS 3,720,024 Theisen................................. 52/185 5 Claims, 12 Drawing Figures may US. Patent Dec. 23, 1975 Sheet 1 of5 3,927,518

U.S. Patent Dec. 23, 1975 Sheet 2 of 5 3,927,518

FIG, 4

US. Patent 1166.23, 1975 Sheet4of5 3,927,518

U.S. Patent Dec. 23, 1975 Sheet 5 of5 3,927,518

SITE ASSEMBLED MULTI-STORY STAIR This invention relates to prefabricated stairs for multi-story buildings adapted to be manufactured at a common site for efficiency in mass production and to be transported as an unassembled unit to a distant site for assembly and installation in the construction of multistory buildings, such as homes, apartments, motels, office or factory buildings.

It will be apparent that commercial success of such prefabricated, multi-story stairway units depends upon the ability to effect material savings in the cost of materials and assembly, and to minimize weight to enable economical handling and transportation of the unassembled units. Shipment in an'unassembled state enables economical transportation of multiple units on conventional transports from the manufacturing site to the building construction site. Another advantage is the ability to stack. one unit onto another in building up the stairway as a sequential function in advance of building construction whereby use can be made of the preinstalled stairway as a means for gaining access to upper floor levels in advance of their construction.

In the latter connection, the prefabricated, multistory stair unit of .this invention is pre-installed in position of use in advance of the construction of the corresponding levels of the building'whereby the pre-installed stairs become available as a means for gaining access to the upper floor levels by members of the building trades thereby to avoid the necessity to construct expensive scaffolding, temporary ladders, elevators or the like, while providing increased safety by reason of the greater stability and more space available with the prefabricated, pre-installed, multi-story stair unit of this invention.

As the floors are completed, including the masonry defining the stairwell, the structural elements of the prefabricated,prednstalled stair assembly are incorporated into the masonry and other structural elements of the building permanently to incorporate the multistory,'pre-installed'unit in the stairwell of the building to become a permanent part thereof. It will be apparent that as the building construction catches up withthe upper levels of the multi-story stair unit, additional units can be stacked one on top of the other to rise above the current level of the building until the stairway rises continuously to the ultimate height of the building. In existing construction of multi-story stair units, use is made of continuous structural members for support In another system presently in use, stair runs and supporting masts are stacked into position as the building progresses. This method does not provide access to the upper working level until such level is in place and requires much more time for erection as erection crews must be brought to the stair location at least twice per story, whereas our stair provides access to upper levels as they are being worked on and two, three, four or more stories of our prestacked stairs can be erected as a unit.

-It has been found that oftentimes the foundation or slab on which the prefabricated unit is pre-installed is not perfectly flat or level. As a result, perfect vertical alignment of the stacked stair units is difficult to achieve or to adjust, especially if the stairs have been assembled and stacked but before they are incorporated as a permanent part of the building. This often leads to instability of the stairs and the need to make major reconstructions or repairs.

It is an object of this invention to provide prefabricated stair units which can be assembled at the building site; which are capable of economical production on a mass production basis to make available units at less cost at the construction site; which occupy minimum space and make use of a minimum amount of material in the prefabricated unit thereby to enable easier handling of the unit and transportation thereof by conventional transports; which are further characterized by a temporary supporting system which is contained entirely within the stairwell and therefore are not required to be embedded in the masonry walls with the resultant minimization of the amount of masonry work and elimination of unnecessary steel support parts; in which certain structural elements such as the landing platform can be folded to provide a prefabricated unit which occupies less space and in which less of the structural elements are exposed to possible damage; in

of the elements in their prefabricated arrangement with the thought that such continuous stair supports would be concealed within the masonry of the walls to tie the stairs into the-building as progress is made in building construction. This imposes a number of limitations with respect to the dimensional characteristics of the prefabricated unit as related to the construction of the stairwell, but theneed to provide structural supports that: fit into the masonry operates undesirably to increase the bulk' as well as the amount .of material required in the prefabricated unit with corresponding increase in weight as-well as the dimension and cost of the assembly. Since the support system remains for incorporation into the walls, building costs are increased by reason of the need to construct the perimeters to embed the support members, including the cutting of masonry blocks toembed the support system.

which a minimum amount of bracing is necessary thereby to reduce the cost and weight of the prefabricated unit, which embodies means for self-alignment thereby to permit proper alignment of the installed prefabricated unit substantially independently of the surface or foundation on which the unit is mounted.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments of the invention are shown in the accompanying drawings in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembled side elevational view of the prefabricated multi-story stair according to the present invention;

FIG. 2 is a plan view of the stair runs and temporary braces utilized in field construction of the present invention;

FIG. 3 is a plan view of the FIG. 2 components in their assembled positions; 4 I

FIG. 4 is an end view along the lines 4-4 of FIG. 3;

FIG. 5 is a plan view of the header channels and newels utilized in the invention;

FIG. 6 is a plan view of the components of FIG. 5 in their field assembled relationship;

FIG. 7 is an end view taken along the lines 7-7 of- FIG.6;-

FIG. 8 is a plan view of the additional stair runs and bracing members required to complete the assembly of the present invention; i

FIG. 9 is a plan view of the completed assembly;

3 FIG. is a view taken along the lines l010 of FIG.

FIG. 11 is a plan view similar to FIG. 9 indicating the manner of attachment of the platform; and

FIG. 12 is a view taken along the lines 12-12 of FIG. 11.

Referring now to the drawings, description will be made of a prefabricated three-story stair assembly embodying the features of this invention, but it will be understood that the concepts of this invention may equally be employed in one, two, four or other multistory units. Each assembled story section is formed with a platform 20, adapted to extend horizontally to provide a landing about midway between the floors 22 and 24. Two lower stair runs 26 and 28 extend angularly downwardly from about one-half of the inner edge of the platform to the floor below and two upper runs of

stairs

29 and 31 extend angularly upwardly from the other half portion of the same inner edge of the platform to the floor above, with the upper stair runs 29 and 31 offset laterally from the lower runs.

Each stair run can be of conventional construction. For example, the construction shown and described in U. S. Pat. No. 3,788,018 assigned to the present assignee may be utilized and such description is incorporated hereby.

The prefabricated multi-story stair unit is constructed with permanent supports in the form of a pair of

newels

40 and 42 represented in FIG. 1 as a pair of vertically disposed parallel metal members such as steel tubular members, angle iron members or the like which are longitudinally spaced by an amount corresponding to the horizontal distance covered by each run of stairs and dimensioned to have a length corresponding to the total height of the prefabricated, multi-story stair unit. The newels are connected by bolting, as will be described, to the adjacent stair runs to provide an assembled relationship therebetween.

At the approximate level where each upper and lower run of stairs meet,

headers

50 and 52 are secured as by bolting to the vertical edges defining the ends of the runs to extend crosswise thereof. The headers are dimensioned to have a length greater than the combined width of the joined stair sections to provide end portions which extend laterally beyond the staircase for anchorage into the wall of the stairwell, thereby to anchor the stair assembly in the installed position in the building.

The longitudinally spaced apart

newels

40 and 42 preferably, though not necessarily, can be allowed to remain as a permanent part of the prefabricated multistory stair unit, especially when prefabricated to receive railings 60 and 62 which are mounted to run parallel with the run of stairs in vertically spaced apart relation thereto. The railings are secured at their ends to vertically spaced portions of the newels. The railings, which do not form an essential part of the assembly, can be installed as by attachment to the newels after installation of the stair unit or by mounting the rails on the walls of the stairwell after the masonry has been completed.

In the prefabricated unit of this invention, it is desirable to provide temporary vertical supports for the sections as a supplement to the support provided by the

newels

40 and 42. Since such temporary supports become superfluous after the

headers

50 and 52 have been anchored into the masonry walls, such vertical supports can be removed after installation of the stair unit has been completed. By reason of their temporary nature, such additional supports are located within the framework of the stair unit so that the prefabricated multistory stair assembly can be constructed without external bracing of the type heretofore required, or as a multi-story stair unit in which the temporary supporting system is contained entirely within the framework and therefore free of the walls of the stairwell.

Such temporary supports are in the form of angle members 66 or other elongate structural elements which extend vertically between the extremities of the stair runs. Support for the bottom run is provided by short angle section 67 which extends vertically downward from the upper end of run 26. Such temporary bracing is secured to the stair runs by bolting through holes 65 and corresponding holes in the stair runs. After the described stair assembly has been installed and the headers have been anchored into the adjacent walls, the temporary bracing, as well as the newels other than those on which the railings are mounted, can be removed to provide full access to the stairway.

The basic unit described, with all of the bracing confined within the frame members enables the prefabricated unit to fit entirely within the stairwell, represents an important feature of this invention. The platforms 20 are desirably supplied as separate elements to be mounted crosswise of the inner ends of the upper and lower runs of stairs between the floors. As illustrated in FIG. 1, the platforms 20 are pivotally mounted to portions of the lower runs immediately above the headers 50 prior to placing the assembled unit in the stairwell. This enables rocking movement of the platform between raised position permitting the assembly to fit within the stairwell and lowered position of use.

Referring now to FIGS. 2-12, the prefabricated unassembled device is shown in a manner so as to illustrate the assembly steps required for on-site construction of the assembly. In the following description the required component parts are indicated in FIGS. 2, 5 and 8, respectively, while the parts indicated in these figures are shown in their assembled relationship to the entire structure in the corresponding FIGS. 3, 6 and 9. These views and the accompanying description are provided in recognition of the fact that one of the principal objects of this invention is to provide a prefabricated stair assembly which can be shipped in the unassembled condition and when ready for use, field assembled by semi-skilled personnel utilizing only bolts.

In prior prefabricated stairs, such as in the referenced US. patent, the stair units could not be assembled at the job site but only at a properly equipped factory. Thus, the assemblies were welded at the factory and shipped three or four stories to a truckload. By utilizing the unassembled configuration of this invention, as many as 24 floors of stairs can be shipped on a single truck. Further, no intermediate warehousing of stairs is necessary but the parts can be shipped directly to a job site from the factory.

In order to begin assembly, a field stacking jig is first prepared. The jig is indicated best in FIG. 4 wherein it comprises a pair of I-

beams

71 and 73. It will be recognized, of course, that the jig can be formed from any relatively level material, the only restraint being that the material should have a height of not less than 6 inches in order to keep the stair unit raised off the ground, and further, the length of the jig should not be less than the length of the stair unit. It will be recognized that the jig itself forms no part of the invention but is merely used to facilitate the stair assembly,

Referring to FIG. 2, the first elements to be installed include the stair runs 29 and 31 and the temporary bracing 66. As indicated in FIG. 3, these items are placed on the

field jig

71, 73 with theproper spacing between the runs. The temporary braces are then bolted to the runs and preferably, the bolting is made only finger-tight at this time. The bolting is accomplished by aligning bolt holes in the runs with corresponding holes 65 in the braces and then passing a threaded bolt therethrough to be secured by a nut. In a similar manner, as will be described, the remaining components of the stair unit are field bolted to the stair flights.

Referring to FIG. 4, the end view of this first assembly step is illustrated. In order to secure the temporary braces to the stair runs, a single bolt is utilized at each end of the temporary braces. Additionally, a cross strut 69 is utilized to maintain the proper width and add lateral rigidity.

Referring next to FIGS. 7, the second stage of assembly is illustrated. In this stage, a construction worker installs the

permanent newels

40, 42 as well as the

header channels

50, 52. In order to increase the clarity of the drawings, the temporary bracing which was installed in the first step is illustrated in FIG. 6 in dashed lines, while the positions of the newels and headers areindicated by solid lines. The newels are bolted in the position shown and then the

header channels

50, 52 are bolted to the end plates of the stair runs 29, 31. Additionally, the header channels are butted against and connected to clip angles 53 mounted on the newel posts to properly position them vertically. Again, the newels and the header channels are bolted fingertight only at this point in the construction. As indicated in FIG. 7, the

headers

50, 52 extend beyond the stair run 29, a short distance generally less than 6 inches, which extension is adapted to be embedded in the masonry for providing permanent anchoring. Similarly, the projections 63 on the header 52 are provided for a like purpose.

Referring now to FIGS. 8-10, a third step in the construction of the field assembled stair is illustrated. In this assembly step the stair runs 26, 28 are installed together with the corresponding temporary bracing elements 66. As indicated in FIG. 9, the stair runs 26, 28 are positioned on top of the partially assembled structure supported on the newels and bolted in place. At this juncture, all the hand-tightened bolts for both sets of stair runs are fully tightened and all the temporary bracing secured in place. The final step in the assembly of the stair is the attaching of the platforms 20.

As indicated in FIGS. 11 and 12, the platforms are attached to a flat bar portion of the header channel 50. The end of the platforms have a curved rodportion 91 which is inserted into an opening in the fiat bar portion of header channel 50. The curvature of this rod permits the platform 20, after attachment, to be placed in the position indicated in dashed lines in FIG. 11. Thus, the platform is maintained flush against the newels and affixed thereto with chain, rope, or other means to hold it in place prior to installation of the unit in the stairwell. If utilized, the railings 60, 62 are next installed. Railings of the type illustrated in FIG. 1 are installed by fastening the railings to the newels preferably with self-tapping screws.

The platform 20 includes a corrugated steel deck 93 (FIG. 12-) fastened onto the upper surface of spaced apart beams 95' and 97 and a header 99 in the form of a steel channel or beam member which extends continuously crosswise beneath the outer end of the deck and beyond the platform. This header is embedded in the masonry walls for support of the platform in the installed position of use. The metal deck portion is conventionally covered with cement or paneling to provide the cross-over landing between the opposite runs of stairs between the floors.

Means are provided temporarily to support the platforms when rocked to their lowered positions during installation. The temporary supports are in the form of elongate rods 101 (FIG. 1) dimensioned to extend angularly between the outer end portion of the lowered platform 20 and the lower portion of one of the temporary supports 66. Additional 'details of the platform construction and deployment are contained in the above referenced U.S. Pat. No. 3,788,018 incorporated hereby. I

The support for the lowermost platform 20 comprises a pair of laterally spaced apart tubular members 103 fixed at their lower ends to a foot 102 in the form of a crosswise extending angle iron which rests on the floor while the platform rests on the upper ends of the vertical rods 103 when lowered to the position of use.

In practice, after the prefabricated multi-story stair unit has been installed in its proper upright position at the desired location, the pivotally mounted platforms are released to enable them to rock gravitationally about their pivot to the lowered position. The angular supporting rods 101 are braced at their lower ends against the vertical brace 66 while the upper end is engaged in a socket on the underside of the platform. The platform comes to rest on the end of the tubular support member which thereafter is effective to retain the platform in the desired horizontal position until the platform headers 99 become anchored in the'masonry of the adjacent walls. Thereafter, the tubular supports 101 can be removed and the stairway finished by covering the platforms landing material.

As previously pointed out, the prefabricated, multistory, stair ;units can be stacked one of the other to enable utilizationof such prefabricated units throughout the height ofa multi-story building. 1

It has been found that oftentimes the floor or slab on which the prefabricated unit is installed may be uneven or sometimes theunit or building settles after installation of the prefabricated stair assembly but before it is incorporated into the building, with the result that the installed unit is not in proper vertical alignment for permanent attachment to the building. Various means which have heretofore been employed to effect alignment, such as shims, have been difficult to install and angular adustment thereby has been difficult to control Thus, a simple and efficient means by which the prefabricated multi-story stair unit of this invention can be adjusted at the time of installation for effecting proper vertical alignment is desirable. For this purpose, the bottom angle irons 69 are provided with spaced openings therein. The openings themselves can be threaded but it is preferred to make use of a threaded nut member secured to the flanged portion in registry with each opening. Threadably engaged in each of said threaded nut members or openings in an elongate bolt. The prefabricated unit installed with a portion of the bolt extending downwardly beyond the opening so that the assembly will rest for support on the throughextending portion of the bolts. When the prefabricated unit has been installed, but before the headers are incorporated permanently into the masonry walls, angular adjustment of the unit is effected by turning one or more of the individual bolts in one direction or the other depending upon whether or not it is desired to raise or lower the particular section of the assembly to compensate for differences in level or angle. The through-extending end portions of the leveling bolts are preferably provided with shoes to distribute the load, as described and illustrated in the above referenced patent.

The assembled prefabricated stair unit is stood upright on a pad or foundation, as by means of a suitable gentry or crane, to position the prefabricated unit upright for installation. When properly positioned, the tradesmen can release the first platform which is then lowered onto the lower tubular supports 103 until the platform comes to rest on the support. The platform at the next level is then released and is lowered onto the next pair of tubular support members. This is continued until all of the platforms have been lowered to horizontal position to define the landings.

Thereafter, the assembly is leveled by proper adjustment of the leveling bolts and the field assembled, prefabricated multi-story stair unit is ready for permanent installation in the building by anchoring the lateral portions of the

headers

50, 52 and 99 in the masonry or walls which define the stairwell. After installation and anchorage of the leaders, the temporary supports are removed to leave the installed stairway free of exposed bracing.

In the meantime, the prefabricated, pre-assembled and pre-installed multi-story stair unit which extends vertically upwardly beyond the floor level is available for use by the tradesmen for access to construct the upper level of the building whereby the multi-story stair unit enjoys considerable utility of great value even before the walls of the stairwell are built for permanent installation of the stairway into the building.

As previously described, one unit can be stacked on another as the building progresses whereby a continuous stairway is provided which projects upwardly beyond the current level of the building for use in construction of such upper levels or to gain access to such upper levels as they are being built.

Thus, the stairs are set in position prior to the construction of the masonry walls thereby affording the various construction trades immediate access to all floor levels as the construction progresses.

lt will be apparent from the foregoing that the stairway assembly embodying the features of this invention represents a unit formed of a supporting system which is confined entirely within the stairwell walls thereby to reduce the amount of masonry work required for installation and minimize the amounts of steel structural supports required for the assembly. The temporary bracing members for the stair sections are all confined within the stairwell to provide unblocked accessibility for mounting the staircase. It will be understood that changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as'defined in the following claims.

We claim:

1. A prefabricated stair unit shipped disassembled to a construction site for field assembly and installation on a field jig, comprising:

a. at least one pair of prefabricated stair flights;

b. headers for bolting to the ends of each flight of stairs and dimensioned to provide an anchoring portion for permanently anchoring said unit in an installed position;

c. newels field bolted to saidpair of stair flights and extending vertically to provide permanent internal support for said unit;

. a platform for each pair of stair flights mounted by field bolting and movable between a vertical position maintained during installation and a horizontal position for permanent use as a landing; and

e. a plurality of temporary supports field bolted to said pair of stair flights during field assembly and removed after installation, said supports located wholly within the stair unit and extending vertically between the outer extremities thereof for temporarily supporting the stair flights in their assembled relation to permit permanent installation, said supports maintaining the flights in a laterally spaced opposite running relation with the upper end of one flight and the lower end of the other flight alongside one another at about midway between the height spanned by the flights.

2. The prefabricated stair unit of claim 1 wherein said platform is mounted to the upper end of one flight at about midway between the height .spanned by the flights by securing means including a curved rod integral with said platform having threads thereon and openings in said stair flight adapted to receive said curved rod for pivotally securing it thereto by bolting.

3. The prefabricated stair unit of claim 1 wherein said unit includes means for leveling said unit after assembly and before permanent installation.

4. The prefabricated stair unit of claim 1 in which the platform includes a header joined to the underside of the platform adjacent the end farthest from the pivotal support and dimensioned to have a length greater than the width of the platform to provide portions extending laterally beyond the platform for anchorage into a wall.

5. The prefabricated stair unit of claim 1 in which the platform comprises a metal deck plate" and bracing members underlying the deck plate and socket openings in the outward extremities of the platform for receipt of temporary bracing'members to support the platform when lowered to horizontal position.

Claims

1. A prefabricated stair unit shipped disassembled to a construction site for field assembly and installation on a field jig, comprising: a. at least one pair of prefabricated stair flights; b. headers for bolting to the ends of each flight of stairs and dimensioned to provide an anchoring portion for permanently anchoring said unit in an installed position; c. newels field bolted to said pair of stair flights and extending vertically to provide permanent internal support for said unit; d. a platform for each pair of stair flights mounted by field bolting and movable between a vertical position maintained during installation and a horizontal position for permanent use as a landing; and e. a plurality of temporary supports field bolted to said pair of stair flights during field assembly and removed after installation, said supports located wholly within the stair unit and extending vertically between the outer extremities thereof for temporarily supporting the stair flights in their assembled relation to permit permanent installation, said supports maintaining the flights in a laterally spaced opposite running relation with the upper end of one flight and the lower end of the other flight alongside one another at about midway between the height spanned by the flights.

2. The prefabricated stair unit of claim 1 wherein said platform is mounted to the upper end of one flight at about midway between the height spanned by the flights by securing means including a curved rod integral with said platform having threads thereon and openings in said stair flight adapted to receive said curved rod for pivotally securing it thereto by bolting.

5. The prefabricated stair unit of claim 1 in which the platform comprises a metal deck plate and bracing members underlying the deck plate and socket openings in the outward extremities of the platform for receipt of temporary bracing members to support the platform when lowered to horizontal position.