US2736482A

US2736482A - Disappearing stairway system

Info

Publication number: US2736482A
Application number: US263544A
Authority: US
Inventors: Clayton B Borden; Jr James T Borden
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-12-27
Filing date: 1951-12-27
Publication date: 1956-02-28
Anticipated expiration: 1973-02-28

Description

Feb 28, 1956 c. B. BORDEN x-:TAL

n DISAPPEARING STAIRWAY SYSTEM Filed Deo. 27, 1951 DEN MJ.

SPE f www mmf n vw WA AM BY @uw United States Patent 2,736,482 DISAPPEARING STAIRWAY SYSTEM Clayton B. Borden and James T. Borden, r., Plantersville, Miss.

Application December 27, 1951, Serial No. 263,544

3 Claims. (Cl. 228-50) The present invention relates to disappearing stairways of the type providing for ceiling installation and for the stairway to be pulled down into the position for use, and to be closed and restored to .its position in the ceiling for storage out of the way.

Stairways for this purpose have heretofore been constructed in a variety of forms. In some instances, the stairway has comprised two or more hinged parts, arranged to be folded together upon the hinged ceiling door. This type when folded and restored to its position of rest in the attic occupies appreciable space above the ceiling door. In addition, it requires appreciable space when being unfolded or folded, and there are serious problems in providing means to insure that the sections are locked in rigid alignment, to prevent the sections from folding at the hinges While the stairway is being used.

Another form in which ceiling-storage stairways have been constructed is with a single rigid stairway or ladder unit arranged to travel in longitudinal guides aixed to the ceiling door, the stairway unit being Vraised to its highest point while the ceiling door is slanted downward, and being then permitted to tip the door upward to its closed position. While this type of stairway system is free from danger of folding while in use, it requires a maximum amount of clearance space in the attic, and seriously interferes with the normal free use of the attic space other than that directly above the ceiling door.

Attempts have heretofore been made to overcome these limitations by constructing the stairway in sections, and arranging the sections to slide together for storage above the ceiling door, .the lower section to be slid downward for extension of the stairway linto its position for use. To arrange for such sections to be in alignment when eX- tended, the Stringer members of the lower section have heretofore been .positioned adjacent the inner surfaces of the stringers for the upper section. Extensive guide brackets designed for minimum friction drag were required, and it was necessary for the steps of the lower section to be 'appreciably shorter than the steps of the upper section, due to the positioning of the stringers vof the lower section within the space between the stringers of the upper section. In such construction, the steps of the upper section were hinged, and were bumped out of their normal positions by direct contact of the upper ends of the stringers against the steps.

An object of the present invention :is to provide an improved stairway system of maximum safety and maximum compactness in its stored condition on the ceiling door.

It is a further object to provide an improved disappearing stairway combining the features of freedom from any danger of untimely folding with the desired retention of uniform maximum length of the stair treads.

Yet a further object is to provide a sliding sectional stairway system providing the maximum usable stairway width for the amount of storage area, and for the overall width of the ceiling door, and to provide therewith a rerice rugged, economical construction characterized by smooth, positive action in extension and retraction.

These objects are met in the present invention by the provision of an extensible and contractible stairway wherein hollow stringers are employed in at .least the upper section, and the respective stringers of the upper and lower sections are arranged for telescopic sliding 'engagement. The stringers of the upper section thus serve as full-length conformal guides for the stringers of the lower section, and 'the treads for both sections are Vmade in the maximum length. Extension pins of the hinged treads of the upper section are arranged to project into the space within the hollow upper Stringer, and are engaged by the upper ends of the stringers of the lower section, folding the upper-section treads out Yof the way as the lower section is moved upward.

A preferred embodiment of the present invention is shown in the appended drawings, wherein- Fig. l is a perspective view-of the stairway system open and extended, in position for use;

Fig. 2 is a detail view of the junction between upper and lower stringers at maximum stairway extension;

Fig. 3 is a cross-sectional view through a pair of telescoped stringers of the upper and lower sections;

Fig. 4 is a detail view showing the hinged connection at `one end of a tread to a stringer of the upper section, the latter being shown in section;

Fig. 5 is a detail view showing the rigid connection at one end of a tread to a Stringer of the lower section, the latter being shown in section; and

Fig. 6 is a longitudinal sectional view through a portion of the partially telescop'ed upper and lower sections of the stairway, showing the action of the Stringer of the lower section in raising the rear edge of a hinged tread of the upper section.

Referring now principally to Fig. 1, the stairway systern comprises a box frame 11, a hinged ceiling door 13 attached thereto and arranged to 'swing down to an inclined position as shown, and upper and lower stairway sections 15 and 17. The upper stairway section 15 comprises left and right

parallel stringers

19 and 21, .respectively, xedly attached to cross-pieces 71, 73 yand 75 on the door 13. Between these stringers are arranged one xed tread or step element 29, and a series of

steps

31, 33, 35, 37 and 39 which are 'hin'g'e-pivoted at their front edges by a pin at each tread-end extending through the adjacent Stringer. Preferably, each of these `treads includes a bracket at each end, and the .hinge pins are connected into the respective brackets, as illustrated in detail in Figs. 4 and 6.

The lower stairway section 17 comprises a. :pair of

parallel stringers

41 and 43 spaced apart on centers by a dimension substantially equal to the center-to-cen'ter spacing dimension 'of the

stringers

19 and 21 yof the upper section 15. Between the stringers -41 and 43 of the `lower section 'are lixedly supported a series of treads or

steps

45, 47, 49, 51 and 53, spaced at 'intervals substantially equal to the intervals of 'the treads or steps of the upper section.

The

stringers

19 and 21 of the upper section are formed of sheet metal, bent along four parallel lines by' means of a brake, to form cross-sections corresponding to channel members with anges partially closing the normally open `channel face. The stringers of the lower section preferably are also formed as hollow tubular members, with their cross-sectional outlines similar to those of the upper stringers. The transverse outside dimensions of the lower section stringers are designed for a slip it .in the upper section stringers, with suicient space being reserved in the upper stringers for the tread hinge pins as heretofore described. The manner in which each lower Stringer slides telescopically .in the corresponding upper Stringer is illustrated in Figs. 2 and 3. Throughs bolts with

roller sleeves

55 and 57 thereon are provided in the lower end of each upper stringer, to facilitate the accurately guided movement of the lower Stringer in the upper one, and to insure accurate alignment of the lower Stringer with the upper one when the stairway is fully extended, as in Fig. 2. These rollers so guide the lower section stringers as to have them pass freely by the hinge bolts of the upper section stringers.

As is apparent in Figs. 1, 2 and 6, the lower section treads are disposed at an appreciable angle to the longitudinal axes of the stringers, e. g., at O-degree angles thereto. Upper section tread 29 is similarly positioned. The remaining upper section treads are free to move about the pivotal axes of the hinge pins, between a position of corresponding angular relation to the stringer axes, and a position substantially parallel to the Stringer axes. Referring particularly to Fig. 6, the hinge action and limits of movement of the upper section treads are illustrated by the positions of

treads

39 and 37, the raising of the lower section having just been commenced, and the upper end of Stringer 43 being at a position intermediate tread 39 and tread 37. The upper ends of the lower section stringers are bias-cut, for engagement with the lift pins of the hinged treads. The hinge

pins connecting treads

37 and 39 to Stringer 21 are illustrated at 61 and 63, respectively, and the lifting pins thereof are illustrated at 65 and 67, respectively.

As shown in Fig. 6, the upper end of Stringer 47 has already engaged pin 67 and has deflected tread 39 .into

the outward position parallel with the longitudinal axes of the stringers, the lifting pin 67 being conned to the position retaining the tread 39 so deected by the front surface of the Stringer 43 which remains in sliding contact therewith. Slots 69 and 71 are provided in the upper inside iiange of Stringer 21 to accommodate the

lifting pins

65 and 67, respectively, as the treads are lifted into their parallel positions, and similar slots are provided in both upper stringers for all of the other tread lifting pins.

The

stringers

41 and 43 of the lower section are of substantially equal length to the

stringers

19 and 21 of the upper section, so that they telescope fully therein. The hinged treads of the upper section, being successively deflected upward as the lower section is telescopically raised, provide ample clearance for the xed treads of the lower section.

The stringers of the upper section are preferably spaced above the upper surface of the ceiling door by a spacing of the order of two inches, as by a series of cross-members 71, 73 and 75 xed to the door 13. This provides clearance room for the climber, so that the toe ends of his shoes may project beyond the treads.

Hinge-pin connected

limit straps

81, 83 and 85, 87 are arranged between the upper section stringers and the box frame 11, for defining the angle at which the door and the upper stairway section are to hang when pulled down for use. Counterbalance means are also provided for the stairway system, with suspension cords, pulleys and counterweights, or with countersprings, the latter being' illustrated at 91 and 93, extending from selected connection points on the upper section stringers to

bracket posts

95 and 97 attached tothe box frame 11.

As many changes could be made .in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended thatall matter contained in the above description or shown in the accompanying drawings shall be interpreted as .illustrative and not in a limiting sense.

What is claimed is:

1. Disappearing stairway apparatus comprising a hinged ceiling door, an upper stairway section rigidly tixed thereto in substantially parallel relation therewith, a lower stairway section slideably engaging said upper stairway section, said lower stairway section being of length and width substantially equal respectively to the length and width of said upper stairway section, said door being slightly longer and wider than said upper and lower stairway sections; said upper stairway section comprising a pair of hollow substantially tubular metal stringers each having a longitudinally extending slit therein, and a series of treads supported by said stringers therebetween; said lower stairway section comprising a pair of stringers each telescopically slideable within the respective stringers of the upper stairway section, a series of treads each anchored securely at both ends to said lower section stringers by fastening means registering with the longitudinal slits in said upper section stringers; means connected to said hinged ceiling door for swinging said door down to a position of a predetermined maximum inclination, the treads of said lower section being substantially horizontal when said door is at said position of maximum inclination, means for limiting said lower section to a range of travel from a fully telescoped position in said upper section to a position of maximum extension whereat telescopic alignment with said upper section is retained, a plurality of the treads of said upper section being hingepivoted at their noses into the respective upper section stringers and having lift pins extending through said longitudinal slits into the interiors of said upper section stringers, said last-named treads normally resting in substantially horizontal positions when said door is in its predetermined inclined position and said lower stairway section is'extended, and said lower section stringers having bias-cut upper ends for engaging the lift pins of successive ones of said upper section treads as said lower section is moved upward into its telescoped position and angularly shifting the successive treads into positions substantially parallel to longitudinal axes of said upper section stringers, the lower section stringers being of less width than the internal width dimension of the upper section stringers whereby said lift pins are accommodated in the intervening internal space above said lower section stringers after the respective treads have been raised into their positions substantially parallel to the axes of said upper section stringers.

2. Disappearing stairway apparatus as defined ,in claim 1, wherein said lift pins on said hinge-pivoted treads of said upper stairway section rest against the edges of said tubular upper stringers at the opposite borders of said longitudinal slits from the respective hinge pivot points, and thereby positively dene the positions of rest of said hinge-pivoted treads when said stairway apparatus is inclined and extended .in its position of use.

3. Disappearing stairway apparatus as defined in claim 1, wherein the uppermost tread of the upper section is rigidly anchored to the upper section stringers, and is substantially horizontal when said door is lowered to said predetermined inclination.

References Cited in the file of this patent UNiTED STATES PATENTS 1,088,056 Bessler Feb. 24, 1914 1,953,038 Bessler Mar. 27, 1934 2,163,142 Frazier June 20, 1939 2,551,208 Garnerv May 1, 1951 FOREIGN PATENTS 428,560 Great Britain May 15, 1935